JP7398964B2 - Manufacturing method of polarizing film - Google Patents

Description

The present invention relates to a method for producing a polarizing film, in which a transparent protective film is provided on at least one surface of a polarizer via an adhesive layer. The polarizing film can be used alone or as an optical film in which the polarizing film is laminated to form an image display device such as a liquid crystal display (LCD), an organic EL display, a CRT, or a PDP.

Liquid crystal display devices are rapidly expanding in the market for watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, and so on. A liquid crystal display device visualizes a polarized state by switching liquid crystal, and uses a polarizer due to its display principle. In particular, in applications such as TVs, higher brightness, higher contrast, and wider viewing angle are required, and polarizing films are also required to have higher transmittance, higher degree of polarization, and higher color reproducibility.

As a polarizer, an iodine-based polarizer with a stretched structure in which iodine is adsorbed to polyvinyl alcohol (hereinafter simply referred to as "PVA") is the most widely used polarizer because it has high transmittance and a high degree of polarization. It is used. Generally, polarizing films are made by laminating transparent protective films on both sides of a polarizer using a so-called water-based adhesive prepared by dissolving a polyvinyl alcohol-based material in water (see Patent Document 1 below). As the transparent protective film, triacetylcellulose or the like having high moisture permeability is used. When the water-based adhesive is used (so-called wet lamination), a drying step is required after the polarizer and the transparent protective film are bonded together.

On the other hand, active energy ray-curable adhesives have been proposed in place of the water-based adhesives. When manufacturing a polarizing film using an active energy ray-curable adhesive, a drying step is not required, so productivity of the polarizing film can be improved.

For example, Patent Document 2 discloses an active energy ray-curable adhesive composition that can easily bond a polyvinyl alcohol film and a plastic film with sufficient strength, and which includes (A) (meth)acrylic radical polymerizable composition; An active energy ray-curable adhesive composition containing a compound, (B) a cationically polymerizable compound, (C) a radical photopolymerization initiator, and (D) a cationic photopolymerization initiator has been proposed.

Japanese Patent Application Publication No. 2001-296427 Patent No. 5046721

In recent years, in the field of optical films such as polarizing films, displays have become thinner and have higher definition, and stricter appearance quality is required. Under such circumstances, measures are needed to suppress the generation of bubbles when bonding the polarizer and the protective film together with an adhesive. As a measure to suppress the generation of bubbles, it is effective to increase the thickness of the adhesive applied or to lower the viscosity of the adhesive, but increasing the thickness of the adhesive may cause the problem of color fading after humidification. There is also the problem that lowering the viscosity of an adhesive increases the constraints to satisfy optical properties and adhesive properties.

Further, as a means for reducing the viscosity of the adhesive, it is effective to incorporate water, which is a non-hazardous substance, into the adhesive. However, in the case of a cationic polymerization type adhesive as described in Patent Document 2, there is a problem that water inhibits the cationic polymerization reaction.

The present invention has solved the above problems, and is capable of continuously and stably producing a polarizing film that has excellent adhesive properties between a polarizer, a transparent protective film, and an adhesive layer, and in which the generation of bubbles is suppressed. The purpose is to provide a method.

The above problem can be solved by the following configuration.

That is, the present invention is a method for producing a polarizing film, in which a transparent protective film is provided on at least one surface of a polarizer via an adhesive layer,
A first coating step of coating an easily adhesive composition containing water and a hydrophilic monomer on the bonding surface of the polarizer while conveying the polarizer to form a wet first coating film;
A second step of forming a second coating film by applying an adhesive composition containing a radically polymerizable compound and a cationic polymerizable compound to the bonding surface of the transparent protective film while conveying the transparent protective film. coating process,
a first thickness measurement step of in-line measuring the thickness of the wet first coating film;
After the first thickness measurement step, a drying step of removing water in the wet first coating film using a dryer to form a dry first coating film;
After the drying step, a second thickness measurement step of in-line measuring the thickness of the dry first coating film;
Adjusting the temperature and/or air volume of the dryer so that the ratio of the thickness of the wet first coating film and the thickness of the dry first coating film obtained by the in-line measurement satisfies the following formula (A). A drying degree adjusting step of adjusting the drying degree of the newly formed dry first coating film,
A paste that forms an uncured adhesive layer by laminating the dry first coating film formed on the pasting surface of the polarizer and the second coating film formed on the pasting surface of the transparent protective film. A method for producing a polarizing film, comprising a step of bonding the polarizer and the transparent protective film through the adhesive layer obtained by curing the uncured adhesive layer, Regarding.
(Thickness of the first dry coating film/thickness of the first wet coating film) - (Content of water in the adhesive composition) ≦0.05 (A)

で表される化合物（ただし、Ｘは反応性基を含む官能基であり、Ｒ^１およびＲ^２はそれぞれ独立に、水素原子、置換基を有してもよい、脂肪族炭化水素基、アリール基、またはヘテロ環基を表す）及び／又は構造式中にＭ－Ｏ結合（Ｍはケイ素、チタン、アルミニウム、またはジルコニウムであり、Ｏは酸素原子である）を有する有機金属化合物を含有することが好ましい。なお、本発明においては、前記一般式（１）で表される化合物を「ホウ素含有化合物」ともいう。 In the above method for producing a polarizing film, the easily adhesive composition has the following general formula (1):

^A compound represented ^by , or a heterocyclic group) and/or an organometallic compound having an MO bond (M is silicon, titanium, aluminum, or zirconium, and O is an oxygen atom) in the structural formula. preferable. In the present invention, the compound represented by the general formula (1) is also referred to as a "boron-containing compound."

で表される化合物（ただし、Ｙは有機基であり、Ｘ、Ｒ^１およびＲ^２は前記と同じ）であることが好ましい。 In the method for producing a polarizing film, the compound represented by the general formula (1) is represented by the following general formula (1')

A compound represented by (where, Y is an organic group, and X, R ¹ and R ² are the same as above) is preferable.

In the above method for producing a polarizing film, the reactive group possessed by the compound represented by the general formula (1) is an α,β-unsaturated carbonyl group, a vinyl group, a vinyl ether group, an epoxy group, an oxetane group, an amino group, It is preferably at least one reactive group selected from the group consisting of an aldehyde group, a mercapto group, and a halogen group.

In the method for producing a polarizing film, the moisture content of the polarizer is preferably 15% by mass or less.

In the method for manufacturing a polarizing film, the first coating step and the second coating step are preferably coating steps using a post-metering coating method.

In the above method for producing a polarizing film, the post-metering coating method is preferably a gravure roll coating method using a gravure roll.

In the method for producing a polarizing film of the present invention, water is added to an easily adhesive composition to be applied to the bonding surface of a polarizer to suppress bubble generation by lowering the viscosity, while a transparent protective film is bonded to the adhesive composition. The adhesive composition applied to the surface is characterized by containing a radically polymerizable compound and a cationic polymerizable compound to improve adhesiveness.

In continuous production of polarizing films, if water remains in the first coating film obtained by coating the adhesive composition on the bonding surface of the polarizer, the first coating film and the adhesive Water remains in the uncured adhesive layer obtained by laminating the second coating film obtained by applying the composition. As a result, a problem occurs in that the cationic polymerization reaction of the uncured adhesive layer is inhibited, and the adhesiveness of the adhesive layer decreases. Therefore, water in the first coating film needs to be removed in the drying process. In the drying process, the initial set temperature and set air volume of the dryer are determined based on the amount of water blended into the easy-adhesive composition, and the water in the first coating film is It was assumed that it had been sufficiently removed to the extent that it did not inhibit the cationic polymerization reaction.

However, due to various factors such as deterioration and damage to the drying equipment piping, clogging of the air outlet, and temperature changes in the surrounding environment, variations in the degree of drying of the first coating film occur during the continuous production of polarizing films, and In some cases, water in the coating film was not sufficiently removed, and water remained in the first coating film after the drying process. As a result, as mentioned above, the cationic polymerization reaction of the uncured adhesive layer is inhibited by the remaining water, making it difficult to stably form an adhesive layer with uniform adhesive properties. Therefore, it may be difficult to continuously and stably produce a polarizing film with excellent adhesive properties.

According to the method for producing a polarizing film of the present invention, the temperature of the dryer is set such that the ratio of the thickness of the wet first coating film obtained by in-line measurement to the thickness of the dry first coating film satisfies the above formula (A). By adjusting the degree of drying of the newly formed dry first coating film by adjusting the air volume and/or by adjusting the degree of drying of the newly formed dry first coating film, the dry first coating film from which water has been sufficiently removed with small variations in the degree of dryness can be continuously produced. Moreover, it can be formed stably. Thereby, it is possible to prevent the cationic polymerization reaction of the uncured adhesive layer from being inhibited by residual water, and it is possible to continuously and stably form an adhesive layer with uniform adhesive properties.

As described above, according to the method for producing a polarizing film of the present invention, a polarizing film having excellent adhesion between the polarizer, the transparent protective film, and the adhesive layer, and having a high appearance quality with suppressed generation of bubbles can be continuously produced. It can be produced efficiently and stably.

It is preferable that the easily adhesive composition contains the boron-containing compound. The boron-containing compound can react with a functional group such as a hydroxy group included in the polarizer. This makes it possible to improve the adhesiveness between the polarizer and the adhesive layer, resulting in the effect of improving the water-resistant adhesiveness of the polarizing film. Here, if the moisture content of the polarizer is low, for example, if the moisture content of the polarizer is 15% by mass or less, the boron-containing compound and the functional group provided in the polarizer cannot sufficiently react, and this effect may not be sufficient. may not be obtained. However, even if the water content of the polarizer is low, the adhesion-promoting composition contains water, which increases the reactivity of the boron-containing compound to the functional groups of the polarizer, which causes it to adhere to the polarizer. Adhesion to the agent layer can be improved. As a result, even when the moisture content of the polarizer is low, it is possible to improve the water-resistant adhesion of the polarizing film, improve the coatability of the adhesive composition, and suppress the generation of bubbles in the polarizing film. .

It is preferable that the easily adhesive composition contains the organometallic compound. The organometallic compound becomes an active metal species through the presence of moisture, and as a result, the organometallic compound can form a strong bond with the polarizer. However, since the organometallic compound has a plurality of reactive points, the organometallic compound that has reacted with the polarizer still has unreacted points. The organometallic compound can form a strong bond with the curable component in the second coating film formed on the bonding surface of the transparent protective film. As mentioned above, since the organometallic compound can form a strong bond with both the polarizer and the adhesive layer, the water-resistant adhesion between the polarizer and the adhesive layer is dramatically improved.

The first coating step and the second coating step are preferably coating steps using a post-metering coating method. Thereby, while improving the adhesiveness of the polarizing film, it is possible to improve the coating properties when applying the easy-adhesion composition and the adhesive composition, and also to improve the coating properties of the first coating film and the second coating film. Thickness uniformity can be improved. In the present invention, the term "post-metered coating method" means a method in which an external force is applied to the liquid film to remove excess liquid to obtain a predetermined coating film thickness. Specific examples of the post-metering coating method include a gravure roll coating method, a forward roll coating method, an air knife coating method, and a rod/bar coating method.

It is a schematic diagram showing an example of the manufacturing method of the polarizing film of the present invention.

The present invention is a method for producing a polarizing film, in which a transparent protective film is provided on at least one surface of a polarizer via an adhesive layer,
A first coating step of coating an easily adhesive composition containing water and a hydrophilic monomer on the bonding surface of the polarizer while conveying the polarizer to form a wet first coating film;
A second step of forming a second coating film by applying an adhesive composition containing a radically polymerizable compound and a cationic polymerizable compound to the bonding surface of the transparent protective film while conveying the transparent protective film. coating process,
a first thickness measurement step of in-line measuring the thickness of the wet first coating film;
After the first thickness measurement step, a drying step of removing water in the wet first coating film using a dryer to form a dry first coating film;
After the drying step, a second thickness measurement step of in-line measuring the thickness of the dry first coating film;
Adjusting the temperature and/or air volume of the dryer so that the ratio of the thickness of the wet first coating film and the thickness of the dry first coating film obtained by the in-line measurement satisfies the following formula (A). A drying degree adjusting step of adjusting the drying degree of the newly formed dry first coating film,
A paste that forms an uncured adhesive layer by laminating the dry first coating film formed on the pasting surface of the polarizer and the second coating film formed on the pasting surface of the transparent protective film. and an adhesion step of adhering the polarizer and the transparent protective film via the adhesive layer obtained by curing the uncured adhesive layer.
(Thickness of the first dry coating film/thickness of the first wet coating film) - (Content of water in the adhesive composition) ≦0.05 (A)

Hereinafter, the method for producing a polarizing film of the present invention will be explained in detail.

<Easy adhesive composition>
The easily adhesive composition contains at least water and a hydrophilic monomer.

The hydrophilic monomer is not particularly limited as long as it is a water-soluble monomer, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, monobutyl hydroxy fumarate, and monobutyl monomer. Carboxy group-containing monomers such as hydroxyitaconate, and salts thereof; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, diethylene glycol mono(meth)acrylate, Hydroxyl group-containing monomers such as ethylene glycol mono(meth)acrylate and polyethylene glycol mono(meth)acrylate; Acrylamide monomers such as (meth)acrylamide, diacetone acrylamide, and N-methylol(meth)acrylamide; N-acryloylmorpholine, Heterocycle-containing (meth)acrylamide derivatives such as N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and polyethylene glycol di(meth)acrylate Examples include ester compounds at both ends of an ethylene glycol oligomer such as ester compounds at both ends of an ethylene glycol oligomer; and ester compounds at both ends of a propylene glycol oligomer. These may be used alone or in combination of two or more. Among these, it is preferable to use a hydroxyl group-containing monomer.

The content of the hydrophilic monomer in the adhesive composition is not particularly limited, but from the viewpoint of improving adhesiveness, it is preferably 20% by mass or more, more preferably 40% by mass or more, and preferably 80% by mass or less, more preferably Preferably it is 65% by mass or less.

^The easy-adhesive composition ^may contain ^{a polymerizable} compound good.

^{The polymerizable compound _} The following compounds can be used without limitation. Examples of the polymerizable compound X include N-methoxymethylacrylamide (SP value 22.9) and N-ethoxymethylacrylamide (SP value 22.3). Note that commercially available products can also be suitably used as the polymerizable compound Examples include Wasmer 3MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.4). These may be used alone or in combination of two or more.

Here, the method for calculating the SP value (solubility parameter) in the present invention will be explained below.

（ただしΔｅｉは原子または基に帰属する２５℃における蒸発エネルギー、Δｖｉは２５℃におけるモル体積である）にて計算して求めることができる。 (Calculation method of solubility parameter (SP value))
In the present invention, the solubility parameter (SP value) of the polymerizable compound , pages 148-154], that is,

(However, Δei is the evaporation energy at 25° C. attributed to the atom or group, and Δvi is the molar volume at 25° C.).

In the above formula, Δei and Δvi represent fixed numerical values given to i atoms and groups in the main molecule. Further, representative examples of numerical values of Δe and Δv given to atoms or groups are shown in Table 1 below.

The content of the polymerizable compound X in the adhesive composition is not particularly limited, but is preferably 0.5% by mass or less.

で表される化合物（ただし、Ｘは反応性基を含む官能基であり、Ｒ^１およびＲ^２はそれぞれ独立に、水素原子、置換基を有してもよい、脂肪族炭化水素基、アリール基、またはヘテロ環基を表す）を含有することが好ましい。前記脂肪族炭化水素基としては、炭素数１～２０の置換基を有してもよい直鎖または分岐のアルキル基、炭素数３～２０の置換基を有してもよい環状アルキル基、炭素数２～２０のアルケニル基が挙げられ、アリール基としては、炭素数６～２０の置換基を有してもよいフェニル基、炭素数１０～２０の置換基を有してもよいナフチル基などが挙げられ、ヘテロ環基としては例えば、少なくとも一つのヘテロ原子を含む、置換基を有してもよい５員環または６員環の基が挙げられる。これらは互いに連結して環を形成してもよい。一般式（１）中、Ｒ^１およびＲ^２として好ましくは、水素原子、炭素数１～３の直鎖または分岐のアルキル基であり、最も好ましくは、水素原子である。なお、一般式（１）で表される化合物は、最終的に形成される接着剤層中に未反応の状態で存在しても良く、各官能基が反応した状態で存在しても良い。 Further, the easily adhesive composition has the following general formula (1):

^A compound represented ^by , or a heterocyclic group). The aliphatic hydrocarbon group includes a linear or branched alkyl group which may have a substituent having 1 to 20 carbon atoms, a cyclic alkyl group which may have a substituent having 3 to 20 carbon atoms, and a carbon Examples of the aryl group include a phenyl group which may have a substituent having 6 to 20 carbon atoms, a naphthyl group which may have a substituent having 10 to 20 carbon atoms, etc. Examples of the heterocyclic group include a 5-membered or 6-membered ring group containing at least one heteroatom and which may have a substituent. These may be connected to each other to form a ring. In general formula (1), R ¹ and R ² are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, and most preferably a hydrogen atom. Note that the compound represented by the general formula (1) may exist in an unreacted state in the adhesive layer that is finally formed, or may exist in a state in which each functional group has reacted.

X possessed by the compound represented by general formula (1) is a functional group containing a reactive group, and is a functional group capable of reacting with the curable component constituting the adhesive layer. For example, hydroxy group, amino group, aldehyde group, carboxy group, vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, α,β-unsaturated carbonyl group, mercapto group, halogen group, etc. When the adhesive composition constituting the adhesive layer is active energy ray-curable, the reactive group contained in X is a vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy It is preferable that it is at least one reactive group selected from the group consisting of X, oxetane, and mercapto groups. The reactive group contained in is preferably at least one reactive group selected from the group consisting of a (meth)acryl group, a styryl group, and a (meth)acrylamide group, and is represented by general formula (1). When the compound has a (meth)acrylamide group, it is more preferable because the reactivity is high and the copolymerization rate with the active energy ray adhesive composition is increased. Further, since the (meth)acrylamide group has high polarity and excellent adhesive properties, it is also preferable from the viewpoint that the effects of the present invention can be efficiently obtained. Furthermore, since the adhesive composition of the present invention constituting the adhesive layer is cationically polymerizable, the reactive groups contained in X include hydroxy group, amino group, aldehyde, carboxy group, vinyl ether group, epoxy group, and oxetane group It is preferable that the adhesive has at least one functional group selected from , mercapto group, etc. In particular, when it has an epoxy group, it is preferable because it has excellent adhesion between the resulting adhesive layer and the adherend, and when it has a vinyl ether group, it is preferable that the adhesive has at least one functional group selected from This is preferred because the composition has excellent curability.

で表される化合物（ただし、Ｙは有機基であり、Ｘ、Ｒ^１およびＲ^２は前記と同じ）が挙げられる。さらに好適には、以下の化合物（１ａ）～（１ｄ）が挙げられる。 Preferred specific examples of the compound represented by general formula (1) include the following general formula (1')

(However, Y is an organic group, and X, R ¹ and R ² are the same as above). More preferred are the following compounds (1a) to (1d).

In the present invention, the compound represented by the general formula (1) may be one in which the reactive group and the boron atom are directly bonded, but as shown in the above specific example, the compound represented by the general formula (1) The compound represented by is preferably a compound in which a reactive group and a boron atom are bonded via an organic group, that is, a compound represented by general formula (1'). When the compound represented by general formula (1) is bonded to a reactive group via, for example, an oxygen atom bonded to a boron atom, the water-resistant adhesion of the polarizing film tends to deteriorate. On the other hand, the compound represented by the general formula (1) does not have a boron-oxygen bond, but has a boron-carbon bond and a reactive group due to the boron atom and an organic group bonding. (General formula (1')) is preferable because the water-resistant adhesiveness of the polarizing film is improved. The organic group specifically refers to an organic group having 1 to 20 carbon atoms, which may have a substituent, and more specifically, having a substituent having 1 to 20 carbon atoms. a linear or branched alkylene group which may have a substituent having 3 to 20 carbon atoms; a cyclic alkylene group which may have a substituent having 6 to 20 carbon atoms; a phenylene group which may have a substituent having 6 to 20 carbon atoms; Examples include a naphthylene group which may have 20 substituents.

In addition to the compounds exemplified above, compounds represented by general formula (1) include esters of hydroxyethyl acrylamide and boric acid, esters of methylol acrylamide and boric acid, esters of hydroxyethyl acrylate and boric acid, and hydroxybutyl acrylate. Examples include esters of (meth)acrylate and boric acid, such as esters of acrylate and boric acid.

If the content of the compound represented by general formula (1) in the easy-adhesive composition is too small, the proportion of the compound represented by general formula (1) present at the interface between the polarizer and the adhesive layer will decrease. However, the adhesion effect may be reduced. Therefore, the content of the compound represented by general formula (1) in the easily adhesive composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and 0.01% by mass or more, more preferably 0.05% by mass or more. It is more preferably 1% by mass or more, and particularly preferably 0.5% by mass or more. In addition, the content of the compound represented by general formula (1) in the easy-adhesive composition is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. .

Further, the easily adhesive composition preferably contains an organometallic compound having an MO bond (M is silicon, titanium, aluminum, or zirconium, and O is an oxygen atom) in the structural formula. Note that the organometallic compound may exist in an unreacted state in the adhesive layer that is finally formed, or may exist in a state in which each functional group has reacted.

The organometallic compound has an MO bond (M is silicon, titanium, aluminum, or zirconium, and O is an oxygen atom) in the structural formula. The organometallic compound is preferably at least one selected from the group consisting of organosilicon compounds, metal alkoxides, and metal chelates.

As the organosilicon compound, those having a Si--O bond can be used without particular limitation, but specific examples include organosilicon compounds that are curable with active energy rays or organosilicon compounds that are not curable with active energy rays. can be mentioned. In particular, it is preferable that the organic group contained in the organosilicon compound has 3 or more carbon atoms. Specific examples of active energy ray-curable compounds include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. , 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane Examples include roxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

Preferred are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

As the compound that is not curable with active energy rays, a compound having an amino group is preferable. Specific examples of compounds having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldimethoxysilane. Ethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2- aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(2-(2-aminoethyl)aminoethyl)aminopropyltrimethoxysilane, γ-(6- aminohexyl)aminopropyltrimethoxysilane, 3-(N-ethylamino)-2-methylpropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyl Trimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N- Amino group-containing silanes such as phenylaminomethyltrimethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine; N-(1,3 Examples include ketimine type silanes such as -dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine.

Only one type of compound having an amino group may be used, or a plurality of types may be used in combination. Among these, to ensure good adhesion, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane , γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)- 1-propanamine is preferred.

Specific examples of compounds other than those listed above that are not curable with active energy rays include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, Examples include (triethoxysilylpropyl)tetrasulfide, 3-isocyanatepropyltriethoxysilane, and imidazolesilane.

The metal alkoxide is a compound in which at least one alkoxy group, which is an organic group, is bonded to a metal, and the metal chelate is a compound in which an organic group is bonded or coordinated to a metal via an oxygen atom. Preferred metals are titanium, aluminum, and zirconium. Among these, aluminum and zirconium have faster reactivity than titanium, which may shorten the pot life of the adhesive composition and reduce the effect of improving water-resistant adhesion. Therefore, from the viewpoint of improving the water-resistant adhesion of the adhesive layer, titanium is more preferable as the metal of the organometallic compound.

When the easy-adhesion composition contains a metal alkoxide as an organometallic compound, it is preferable to use a metal alkoxide having an organic group having 3 or more carbon atoms, and more preferably 6 or more carbon atoms. When the number of carbon atoms is 2 or less, the pot life of the adhesive composition becomes short, and the effect of improving water-resistant adhesion may be reduced. An example of the organic group having 6 or more carbon atoms is an octoxy group, which can be preferably used. Suitable metal alkoxides include, for example, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetraoctyl titanate, tertiary amyl titanate, tetratertiary butyl titanate, tetrastearyl titanate, zirconium tetraisopropoxide, zirconium tetranormal Butoxide, zirconium tetraoctoxide, zirconium tetratertiary butoxide, zirconium tetrapropoxide, aluminum sec butyrate, aluminum ethylate, aluminum isoprepylate, aluminum butyrate, aluminum diisopropylate monosecondary butyrate, monosec butoxyaluminum diisopropylate rate, etc. Among them, tetraoctyl titanate is preferred.

When the easily bonding composition contains a metal chelate as an organometallic compound, it is preferable that the metal chelate contains an organic group having 3 or more carbon atoms. When the number of carbon atoms is 2 or less, the pot life of the adhesive composition becomes short, and the effect of improving the water-resistant adhesion of the polarizing film may be reduced. Examples of the organic group having 3 or more carbon atoms include an acetylacetonate group, an ethyl acetoacetate group, an isostearate group, and an octylene glycolate group. Among these, an acetylacetonate group or an ethyl acetoacetate group is preferable as the organic group from the viewpoint of improving the water-resistant adhesion of the adhesive layer. Suitable metal chelates include, for example, titanium acetylacetonate, titanium octylene glycolate, titanium tetraacetylacetonate, titanium ethylacetoacetate, polyhydroxytitanium stearate, dipropoxy-bis(acetylacetonato)titanium, dibutoxytitanium. -bis(octylene glycolate), dipropoxytitanium-bis(ethyl acetoacetate), titanium lactate, titanium diethanolaminate, titanium triethanolaminate, dipropoxytitanium-bis(lactate), dipropoxytitanium-bis(triethanol) aminato), di-n-butoxytitanium-bis(triethanolaminate), tri-n-butoxytitanium monostearate, diisopropoxy bis(ethyl acetoacetate) titanium, diisopropoxy bis(acetylacetate) Titanium, diisopropoxy bis(acetylacetone) titanium, titanium phosphate compound, titanium lactate ammonium salt, titanium-1,3-propanedioxybis(ethylacetoacetate), titanium dodecylbenzenesulfonic acid compound, titanium aminoethylaminoethano zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bisethyl acetoacetate, zirconium acetate, tri-n-butoxyethylacetoacetate zirconium, di-n-butoxybis(ethyl acetate) acetate) zirconium, n-butoxytris (ethylacetoacetate) zirconium, tetrakis (n-propylacetoacetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium, aluminum ethyl acetoacetate, aluminum acetylacetonate , aluminum acetylacetonate bisethylacetoacetate, diisopropoxyethylacetoacetate aluminum, diisopropoxyacetylacetonate aluminum, isopropoxy bis(ethylacetoacetate) aluminum, isopropoxy bis(acetylacetonate) aluminum, tris(ethylacetoacetate) acetate) aluminum, tris(acetylacetonate) aluminum, and monoacetylacetonato bis(ethylacetoacetate) aluminum. Among these, titanium acetylacetonate and titanium ethyl acetoacetate are preferred.

In addition to the above, organic metal compounds that can be used in the present invention include metal salts of organic carboxylic acids such as zinc octylate, zinc laurate, zinc stearate, and tin octylate, zinc acetylacetone chelate, zinc benzoylacetone chelate, and zinc dibenzoylmethane. Chelates, zinc chelate compounds such as ethyl acetoacetate zinc chelate, and the like.

If the content of the organometallic compound in the adhesion-promoting composition is too small, the proportion of the organometallic compound present at the interface between the polarizer and the adhesive layer may decrease, and the adhesion-promoting effect may become low. Therefore, the content of the organometallic compound in the adhesive composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and 0.1% by mass or more. is even more preferable. Further, the content of the organometallic compound in the adhesive composition is usually 10% by mass or less.

The easily adhesive composition contains water as a solvent. Although an organic solvent may be blended into the adhesive composition within a range that does not impair the effects of the present invention, it is preferable not to blend an organic solvent.

The easily adhesive composition may contain additives.

Examples of the additives include binder resins, surfactants, plasticizers, tackifiers, low molecular weight polymers, polymerizable monomers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, and ultraviolet rays. Examples include absorbents, polymerization inhibitors, silane coupling agents, titanium coupling agents, inorganic or organic fillers, metal powders, particles, foils, and the like.

<Adhesive composition>
The adhesive composition of the present invention may be thermosetting or active energy ray curable. Examples of resins constituting the thermosetting adhesive composition include polyvinyl alcohol resins, epoxy resins, unsaturated polyesters, urethane resins, acrylic resins, urea resins, melamine resins, and phenolic resins, and if necessary, a curing agent may be added. Use in combination. As the resin constituting the thermosetting adhesive composition, polyvinyl alcohol resin and epoxy resin can be more preferably used. Active energy ray curable adhesive compositions can be broadly classified into electron beam curable, ultraviolet ray curable, and visible light curable based on active energy rays. Further, according to the curing reaction, adhesive compositions are classified into radically polymerizable adhesive compositions and cationically polymerizable adhesive compositions, and in the present invention, radically polymerizable and cationically polymerizable adhesive compositions are used. In the present invention, active energy rays with a wavelength range of 10 nm to less than 380 nm are referred to as ultraviolet rays, and active energy rays with a wavelength range of 380 nm to 800 nm are referred to as visible rays.

In the method for producing a polarizing film of the present invention, it is preferable that the adhesive composition is curable with active energy rays. Furthermore, it is particularly preferable that the material is visible light curable using visible light of 380 nm to 450 nm.

The adhesive composition of the present invention contains at least a radically polymerizable compound and a cationic polymerizable compound.

Examples of the radically polymerizable compound include compounds having a radically polymerizable functional group of a carbon-carbon double bond such as a (meth)acryloyl group and a vinyl group. Either a monofunctional radically polymerizable compound or a difunctional or more polyfunctional radically polymerizable compound can be used. Further, these radically polymerizable compounds can be used alone or in combination of two or more. As these radically polymerizable compounds, for example, compounds having a (meth)acryloyl group are suitable. In the present invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning hereinafter.

で表される化合物（ただし、Ｒ^３は水素原子またはメチル基であり、Ｒ^４およびＲ^５はそれぞれ独立に、水素原子、アルキル基、ヒドロキシアルキル基、アルコキシアルキル基または環状エーテル基であって、Ｒ^４およびＲ^５は環状複素環を形成してもよい）が挙げられる。アルキル基、ヒドロキシアルキル基、および／またはアルコキシアルキル基のアルキル部分の炭素数は特に限定されないが、例えば１～４個のものが例示される。また、Ｒ^４およびＲ^５が形成してもよい環状複素環は、例えばＮ－アクリロイルモルホリンなどが挙げられる。 Examples of the monofunctional radically polymerizable compound include the following general formula (2):

^A compound ^{represented by} R ⁴ and R ⁵ may form a cyclic heterocycle). The number of carbon atoms in the alkyl moiety of the alkyl group, hydroxyalkyl group, and/or alkoxyalkyl group is not particularly limited, and examples thereof include 1 to 4 carbon atoms. Examples of the cyclic heterocycle that R ⁴ and R ⁵ may form include N-acryloylmorpholine.

Specific examples of the compound represented by general formula (2) include N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-isopropyl ( N-alkyl group-containing (meth)acrylamide derivatives such as meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide; N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N- - N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as methylol-N-propane (meth)acrylamide; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; It will be done. Examples of the cyclic ether group-containing (meth)acrylamide derivatives include heterocycle-containing (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle, such as N-acryloylmorpholine, N-acryloylmorpholine, - Acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, etc.

Further, the adhesive composition may contain a monofunctional radically polymerizable compound other than the above as a curable component. Examples of the monofunctional radically polymerizable compound include various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Examples of the (meth)acrylic acid derivatives include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and 2-methyl-2-nitropropyl (meth)acrylate. , n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl- Examples include (meth)acrylic acid (1-20 carbon atoms) alkyl esters such as 2-propylpentyl (meth)acrylate and n-octadecyl (meth)acrylate.

The (meth)acrylic acid derivatives include, for example, cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, ) acrylate, polycyclic (meth)acrylates such as dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxy Ethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, alkylphenoxypolyethylene glycol (meth)acrylate, etc. Examples include (meth)acrylates containing an alkoxy group or a phenoxy group. Among these, dicyclopentenyloxyethyl acrylate and phenoxyethyl acrylate are preferred because they have excellent adhesion to various protective films.

In addition, examples of the (meth)acrylic acid derivatives include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, Hydroxyalkyl (meth)acrylate such as 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, etc. ) acrylate, hydroxyl group-containing (meth)acrylates such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate; glycidyl (meth) Acrylate, epoxy group-containing (meth)acrylate such as 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethyl ethyl (meth)acrylate , tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, etc. containing halogens. (Meth)acrylate; Alkylaminoalkyl (meth)acrylate such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate; ) acrylate, oxetane group-containing (meth)acrylates such as 3-butyl-oxetanylmethyl (meth)acrylate, 3-hexy-oxetanylmethyl (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, butyrolactone (meth)acrylate, etc. Examples include (meth)acrylates having a heterocycle, neopentyl glycol (meth)acrylic acid adducts of hydroxypivalate, and p-phenylphenol (meth)acrylate. Among these, 2-hydroxy-3-phenoxypropyl acrylate is preferred because it has excellent adhesion to various protective films.

In addition, monofunctional radically polymerizable compounds include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, ω-carboxy- Examples include carboxy group-containing monomers such as polycaprolactone mono(meth)acrylate.

Examples of monofunctional radically polymerizable compounds include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, Examples include vinyl monomers having a nitrogen-containing heterocycle such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

The adhesive composition of the present invention contains highly polar hydroxyl group-containing (meth)acrylates, carboxyl group-containing (meth)acrylates, phosphoric acid group-containing (meth)acrylates, etc. among monofunctional radically polymerizable compounds. By doing so, the adhesion to various base materials is improved. The content of the hydroxyl group-containing (meth)acrylate is preferably 1% by mass to 30% by mass based on the adhesive composition. If the content of the hydroxyl group-containing (meth)acrylate is too large, the water absorption rate of the cured product may become high and the water resistance may deteriorate. The content of the carboxy group-containing (meth)acrylate is preferably 1% by mass to 20% by mass based on the adhesive composition. If the content of the carboxy group-containing (meth)acrylate is too large, it is not preferable because the optical durability of the polarizing film decreases. As the phosphoric acid group-containing (meth)acrylate, 2-(meth)acryloyloxyethyl acid phosphate may be mentioned, and the content thereof should be 0.1% by mass to 10% by mass based on the adhesive composition. is preferred. If the content of the phosphoric acid group-containing (meth)acrylate is too large, it is not preferable because the optical durability of the polarizing film decreases.

Further, as the monofunctional radically polymerizable compound, a radically polymerizable compound having an active methylene group can be used. A radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the end or in the molecule, and also has an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, and a cyanoacetyl group. Preferably, the active methylene group is an acetoacetyl group. Examples of radically polymerizable compounds having an active methylene group include acetoacetoxy compounds such as 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, and 2-acetoacetoxy-1-methylethyl (meth)acrylate. Alkyl (meth)acrylate; 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N -(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide, and the like. The radically polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth)acrylate.

In addition, examples of polyfunctional radically polymerizable compounds having difunctionality or more include N,N'-methylenebis(meth)acrylamide, which is a polyfunctional (meth)acrylamide derivative, tripropylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. (meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, ) acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di (meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate (meth)acrylic acids such as acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerin tetra(meth)acrylate and polyhydric alcohols. Esterified products include 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include Aronix M-220 (manufactured by Toagosei Co., Ltd.), Light Acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), and Light Acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.). (manufactured by Sartomer), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer), etc. are preferred. Further, if necessary, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, and various (meth)acrylate monomers may be used. Note that the polyfunctional (meth)acrylamide derivative has a fast polymerization rate and excellent productivity, and also has excellent crosslinking properties when the adhesive composition is made into a cured product, so it is preferable to include it in the adhesive composition.

Radical polymerizable compounds should be used in combination with monofunctional radical polymerizable compounds and polyfunctional radical polymerizable compounds from the viewpoint of achieving both adhesion with polarizers and various transparent protective films and optical durability in harsh environments. is preferred. Note that since the monofunctional radically polymerizable compound has a relatively low liquid viscosity, the liquid viscosity of the adhesive composition can be reduced by including it in the adhesive composition. In addition, monofunctional radically polymerizable compounds often have functional groups that exhibit various functions, and by incorporating them into adhesive compositions, various types of monofunctional radically polymerizable compounds can be added to adhesive compositions and/or cured products of adhesive compositions. Function can be expressed. The polyfunctional radically polymerizable compound is preferably included in the adhesive composition because it can three-dimensionally crosslink the cured product of the adhesive composition. The polyfunctional radically polymerizable compound is preferably used in an amount of 10 to 1000 parts by mass based on 100 parts by mass of the monofunctional radically polymerizable compound.

The content of the radically polymerizable compound in the adhesive composition is preferably 55 to 80% by mass, more preferably 65 to 80% by mass, and even more preferably 67 to 75% by mass, from the viewpoint of improving the adhesiveness of the adhesive layer. %.

When an electron beam or the like is used as the active energy ray, it is not necessary for the adhesive composition to contain a photoradical polymerization initiator. However, when an ultraviolet ray or visible ray is used as the active energy ray, the adhesive composition Preferably, the material contains a photoradical polymerization initiator.

The photoradical polymerization initiator is appropriately selected depending on the active energy ray. When curing with ultraviolet rays or visible rays, a photoradical polymerization initiator cleaved by ultraviolet rays or visible rays is used. Examples of the photoradical polymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2 Aromatic ketone compounds such as -propyl)ketone, α-hydroxy-α,α′-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenylketone; methoxyacetophenone, 2,2-dimethoxy- Acetophenone compounds such as 2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, Benzoin alkyl ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; Aromatic ketal compounds such as benzyl dimethyl ketal; Aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; 1- Photoactive oxime compounds such as phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2, Examples include thioxanthone compounds such as 4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxide; acyl phosphonates.

The content of the photoradical polymerization initiator in the adhesive composition is preferably 20% by mass or less, more preferably 0.01 to 20% by mass, and more preferably 0.05 to 10% by mass. is more preferable, and particularly preferably 0.1 to 5% by mass.

When using the visible light curable adhesive composition of the present invention containing a radically polymerizable compound as a curable component, it is recommended to use a photoradical polymerization initiator that is particularly sensitive to light of 380 nm or more. preferable. A photoradical polymerization initiator that is highly sensitive to light of 380 nm or more will be described later.

（式中、Ｒ^６およびＲ^７は－Ｈ、－ＣＨ_２ＣＨ_３、－ｉＰｒまたはＣｌを示し、Ｒ^６およびＲ^７は同一または異なっても良い）を単独で使用するか、あるいは一般式（３）で表される化合物と後述する３８０ｎｍ以上の光に対して高感度な光ラジカル重合開始剤とを併用することが好ましい。一般式（３）で表される化合物を使用した場合、３８０ｎｍ以上の光に対して高感度な光ラジカル重合開始剤を単独で使用した場合に比べて接着性に優れる。一般式（３）で表される化合物の中でも、Ｒ^６およびＲ^７が－ＣＨ_２ＣＨ_３であるジエチルチオキサントンが特に好ましい。接着剤組成物中の一般式（３）で表される化合物の組成比率は、接着剤組成物の全量に対して、０．１～５質量％であることが好ましく、０．５～４質量％であることがより好ましく、０．９～３質量％であることがさらに好ましい。 As the photoradical polymerization initiator, a compound represented by the following general formula (3);

(wherein R ⁶ and R ⁷ represent -H, -CH ₂ CH ₃ , -iPr or Cl, and R ⁶ and R ⁷ may be the same or different), or the general formula ( It is preferable to use the compound represented by 3) in combination with a photoradical polymerization initiator that is highly sensitive to light of 380 nm or more, which will be described later. When the compound represented by the general formula (3) is used, adhesiveness is superior to when a photoradical polymerization initiator that is highly sensitive to light of 380 nm or more is used alone. Among the compounds represented by the general formula (3), diethylthioxanthone in which R ⁶ and R ⁷ are -CH ₂ CH ₃ is particularly preferred. The composition ratio of the compound represented by general formula (3) in the adhesive composition is preferably 0.1 to 5% by mass, and 0.5 to 4% by mass, based on the total amount of the adhesive composition. %, and even more preferably 0.9 to 3% by mass.

Moreover, it is preferable to add a polymerization initiation aid if necessary. Examples of polymerization initiation aids include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, etc. Ethyl 4-dimethylaminobenzoate is particularly preferred. When a polymerization initiation aid is used, the amount added is usually 0 to 5% by weight, preferably 0 to 4% by weight, and most preferably 0 to 3% by weight, based on the total amount of the adhesive composition.

Furthermore, a known radical photopolymerization initiator can be used if necessary. Since a transparent protective film having UV absorption ability does not transmit light of 380 nm or less, it is preferable to use a photo-radical polymerization initiator that is highly sensitive to light of 380 nm or more as the photo-radical polymerization initiator. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 , 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole- Examples include 1-yl)-phenyl)titanium.

（式中、Ｒ^８、Ｒ^９およびＲ^１０は－Ｈ、－ＣＨ_３、－ＣＨ_２ＣＨ_３、－ｉＰｒまたはＣｌを示し、Ｒ^８、Ｒ^９およびＲ^１０は同一または異なっても良い）を使用することが好ましい。一般式（４）で表される化合物としては、市販品でもある２－メチル－１－（４－メチルチオフェニル）－２－モルフォリノプロパン－１－オン（商品名：ＩＲＧＡＣＵＲＥ９０７ メーカー：ＢＡＳＦ）が好適に使用可能である。その他、２－ベンジル－２－ジメチルアミノ－１－（４－モルフォリノフェニル）－ブタノン－１（商品名：ＩＲＧＡＣＵＲＥ３６９ メーカー：ＢＡＳＦ）、２－（ジメチルアミノ）－２－［（４－メチルフェニル）メチル］－１－［４－（４－モルホリニル）フェニル］－１－ブタノン（商品名：ＩＲＧＡＣＵＲＥ３７９ メーカー：ＢＡＳＦ）が感度が高いため好ましい。 In particular, as a photoradical polymerization initiator, in addition to the photoradical polymerization initiator of general formula (3), a compound further represented by the following general formula (4);

(In the formula, R ⁸ , R ⁹ and R ¹⁰ represent -H, -CH ₃ , -CH ₂ CH ₃ , -iPr or Cl, and R ⁸ , R ⁹ and R ¹⁰ may be the same or different) It is preferable to use As the compound represented by general formula (4), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE907, manufacturer: BASF), which is also a commercial product, is suitable. It can be used for Others include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (product name: IRGACURE369 Manufacturer: BASF), 2-(dimethylamino)-2-[(4-methylphenyl) Methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE379, manufacturer: BASF) is preferred because of its high sensitivity.

In the above adhesive composition, when a radically polymerizable compound having an active methylene group is used as the radically polymerizable compound, it is preferably used in combination with a radical polymerization initiator having a hydrogen abstracting action. According to this configuration, the adhesiveness of the adhesive layer of the polarizing film is significantly improved even in a particularly high humidity environment or immediately after being taken out of water (non-dry state). Although the reason for this is not clear, the following causes are considered. In other words, the radically polymerizable compound having an active methylene group is incorporated into the main chain and/or side chain of the base polymer in the adhesive layer while polymerizing together with other radically polymerizable compounds constituting the adhesive layer. Form a layer of agent. In such a polymerization process, if a radical polymerization initiator with a hydrogen abstracting action is present, hydrogen is abstracted from the radically polymerizable compound having an active methylene group while the base polymer constituting the adhesive layer is formed, and hydrogen is converted into methylene groups. Radicals are generated. Then, the methylene groups generated by the radicals react with the hydroxyl groups of the polarizer such as PVA, and a covalent bond is formed between the adhesive layer and the polarizer. As a result, it is presumed that the adhesiveness of the adhesive layer of the polarizing film is significantly improved, especially even in a non-dry state.

In the present invention, examples of the radical polymerization initiator having a hydrogen abstracting action include thioxanthone radical polymerization initiators, benzophenone radical polymerization initiators, and the like. The radical polymerization initiator is preferably a thioxanthone radical polymerization initiator. Examples of the thioxanthone radical polymerization initiator include the compound represented by the above general formula (3). Specific examples of the compound represented by general formula (3) include thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, and chlorothioxanthone. Among the compounds represented by the general formula (3), diethylthioxanthone in which R ⁶ and R ⁷ are -CH ₂ CH ₃ is particularly preferred.

Cationically polymerizable compounds are classified into monofunctional cationically polymerizable compounds that have one cationically polymerizable functional group in their molecule and multifunctional cationically polymerizable compounds that have two or more cationically polymerizable functional groups in their molecule. .

Since the monofunctional cationic polymerizable compound has a relatively low liquid viscosity, the liquid viscosity of the adhesive composition can be reduced by including it in the adhesive composition. In addition, monofunctional cationic polymerizable compounds often have functional groups that exhibit various functions, and by incorporating them into adhesive compositions, various types of monofunctional cationic polymerizable compounds can be added to adhesive compositions and/or cured products of adhesive compositions. Function can be expressed.

The polyfunctional cationic polymerizable compound can three-dimensionally crosslink the cured product of the adhesive composition.

Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group, and a vinyl ether group.

Examples of the compound having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds, and alicyclic epoxy compounds are preferred from the viewpoint of excellent curability and adhesiveness.

Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, a caprolactone-modified product of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and trimethylcaprolactone. Examples include modified products and modified products of valerolactone. Specifically, Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085 (manufactured by Daicel Chemical Industries, Ltd.), Cylacure UVR-6105, Cylacure UVR-6107, Cylacure 30, R-6110 (all of the above) , manufactured by Dow Chemical Japan Co., Ltd.).

Examples of compounds having an oxetanyl group include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl) Examples include oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, and phenol novolac oxetane. Specific examples include aron oxetane OXT-101, aron oxetane OXT-121, aron oxetane OXT-211, aron oxetane OXT-221, and aron oxetane OXT-212 (all manufactured by Toagosei Co., Ltd.).

Examples of compounds having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol vinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclo Examples include decane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, and pentaerythritol type tetravinyl ether.

The content of the cationic polymerizable compound in the adhesive composition is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and even more preferably 15 to 25% by mass from the viewpoint of improving the adhesiveness of the adhesive layer. %.

Since the adhesive composition of the present invention contains a cationically polymerizable compound as a curable component, it preferably contains a cationic photopolymerization initiator. A photocationic polymerization initiator generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and starts the polymerization reaction of epoxy groups and oxetanyl groups. As the photocationic polymerization initiator, a photoacid generator and a photobase generator can be used, and the photoacid generator described below is preferably used. In addition, when the adhesive composition used in the present invention is used as a visible light curable adhesive composition, it is preferable to use a photocationic polymerization initiator that is particularly sensitive to light of 380 nm or more. Generally, it is a compound that shows maximum absorption in a wavelength range around 300 nm or shorter, so by incorporating a photosensitizer that shows maximum absorption in a longer wavelength range, specifically, a wavelength longer than 380 nm. , can be sensitive to light with a wavelength around this range, and can promote the generation of cationic species or acids from the photocationic polymerization initiator. Examples of photosensitizers include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, etc. You may use a mixture of two or more types. Anthracene compounds are particularly preferred because they have excellent photosensitizing effects, and specific examples include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). The content of the photosensitizer is preferably 0.1% by mass to 5% by mass, more preferably 0.5% by mass to 3% by mass.

（ただし、Ｌ^＋は、任意のオニウムカチオンを表す。また、Ｘ^－は、ＰＦ_６ ^－、ＳｂＦ_６ ^－、ＡｓＦ_６ ^－、ＳｂＣｌ_６ ^－、ＢｉＣｌ_５ ^－、ＳｎＣｌ_６ ^－、ＣｌＯ_４ ^－、ジチオカルバメートアニオン、ＳＣＮ^－よりからなる群より選択されるカウンターアニオンを表す。） Examples of the photoacid generator include compounds represented by the following general formula (5).
General formula (5)

(However, L ⁺ represents any onium cation. X ^- represents PF ₆ ^- , SbF ₆ ^- , AsF ₆ ^- , SbCl ₆ ^- , BiCl ₅ ^- , SnCl ₆ ^- , ClO ₄ ^- , dithiocarbamate Anion, SCN ^- represents a counter anion selected from the group consisting of.)

Next, the counter anion X ⁻ in general formula (5) will be explained.

The counter anion X ^- in general formula (5) is not particularly limited in principle, but is preferably a non-nucleophilic anion. When the counter ^anion It is possible to improve the stability over time of a compound or a composition using the same. The non-nucleophilic anion herein refers to an anion that has a low ability to cause a nucleophilic reaction. Examples of such anions include PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate anion, SCN ^−, and the like.

Specifically, "CylaCure UVI-6992", "CylaCure UVI-6974" (manufactured by Dow Chemical Japan Co., Ltd.), "Adeka Optomer SP150", "Adeka Optomer SP152", "Adeka Optomer SP152", "Adeka Optomer SP170'', ``ADEKA Optomer SP172'' (manufactured by ADEKA Co., Ltd.), ``IRGACURE250'' (manufactured by Ciba Specialty Chemicals), ``CI-5102'', ``CI-2855'' (manufactured by Nippon Soda Co., Ltd.), “SAN-AID SI-60L”, “SUN-AID SI-80L”, “SUN-AID SI-100L”, “SAN-AID SI-110L”, “SUN-AID SI-180L” (manufactured by Sanshin Kagaku Co., Ltd.), “CPI-100P”, "CPI-110P", "CPI-100A" (manufactured by Sun-Apro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (manufactured by Wako Pure Chemical Industries, Ltd.) are preferred specific examples of the photoacid generator of the present invention. It is mentioned as.

The content of the photoacid generator is 10% by mass or less, preferably 0.01 to 10% by mass, and preferably 0.05 to 5% by mass, based on the total amount of the adhesive composition. It is more preferable, and particularly preferably 0.1 to 3% by mass.

The photobase generator can function as a catalyst for the polymerization reaction of radically polymerizable compounds and epoxy resins when its molecular structure changes or its molecules cleave when irradiated with light such as ultraviolet rays or visible light. A compound that produces one or more basic substances. Examples of the basic substance include secondary amines and tertiary amines. Examples of the photobase generator include the above α-aminoacetophenone compound, the above oxime ester compound, an acyloxyimino group, an N-formylated aromatic amino group, an N-acylated aromatic amino group, a nitrobenzylcarbamate group, and an alkyloxyimino group. Examples include compounds having a substituent such as an oxybenzyl carbamate group. Among them, oxime ester compounds are preferred.

Examples of the compound having an acyloxyimino group include O,O'-succinic acid diacetophenone oxime, O,O'-succinic acid diacetophenone oxime, and benzophenone oxime acrylate styrene copolymer.

Examples of compounds having an N-formylated aromatic amino group or an N-acylated aromatic amino group include di-N-(p-formylamino)diphenylmethane, di-N(p-aceethylamino)diphenylmelane, Di-N-(p-benzamido)diphenylmethane, 4-formylaminotoluylene, 4-acetylaminotoluylene, 2,4-diformylaminotoluylene, 1-formylaminonaphthalene, 1-acetylaminotoluylene, 1,5 -diformylaminoanthracene, 1-formylaminoanthracene, 1,4-diformylaminoanthracene, 1-acetylaminoanthracene, 1,4-diformylaminoanthraquinone, 1,5-diformylaminoanthraquinone, 3,3'- Examples include dimethyl-4,4'-diformylaminobiphenyl and 4,4'-diformylaminobenzophenone.

Examples of compounds having a nitrobenzyl carbamate group or an alkoxybenzyl carbamate group include bis{{(2-nitrobenzyl)oxy}carbonyl}diaminodiphenylmethane, 2,4-di{(2-nitrobenzyl)oxy}toluylene, Examples include bis{(2-nitrobenzyloxy)carbonyl}hexane-1,6-diamine and m-xylidine{{(2-nitro-4-chlorobenzyl)oxy}amide}.

The photobase generator is preferably at least one of an oxime ester compound and an α-aminoacetophenone compound, and more preferably an oxime ester compound. Particularly preferred α-aminoacetophenone compounds are those having two or more nitrogen atoms.

Other photobase generators include WPBG-018 (product name: 9-anthrylmethyl N,N'-diethylcarbamate), WPBG-027 (product name: (E)-1-[3-(2-hydroxyphenyl)-2- propenoyl] piperidine), WPBG-082 (product name: guanidinium2-(3-benzoylphenyl) propionate), WPBG-140 (product name: 1-(anthraquinon-2-yl) ethyl imi Use a photobase generator such as dazolecarboxylate) You can also do that.

In the above adhesive composition, a photoacid generator and a compound containing either an alkoxy group or an epoxy group can be used together in the adhesive composition.

When using a compound having one or more epoxy groups in the molecule or a polymer (epoxy resin) having two or more epoxy groups in the molecule, two functional groups that are reactive with epoxy groups are added to the molecule. Compounds having more than one may be used in combination. Examples of the functional group having reactivity with an epoxy group include a carboxyl group, a phenolic hydroxyl group, a mercapto group, and a primary or secondary aromatic amino group. In consideration of three-dimensional curability, it is particularly preferable that one molecule contains two or more of these functional groups.

Examples of polymers having one or more epoxy groups in the molecule include epoxy resins, such as bisphenol A epoxy resin derived from bisphenol A and epichlorohydrin, and bisphenol F epoxy resin derived from bisphenol F and epichlorohydrin. Resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, Naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, multifunctional type epoxy resin such as trifunctional type epoxy resin and tetrafunctional type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin , isocyanurate type epoxy resins, aliphatic chain epoxy resins, etc., and these epoxy resins may be halogenated or hydrogenated. Commercially available epoxy resin products include, for example, JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000 manufactured by Japan Epoxy Resin Co., Ltd., and Epiclon manufactured by DIC Corporation. 830, EXA835LV, HP4032D, HP820, EP4100 series, EP4000 series, EPU series manufactured by ADEKA Corporation, Celoxide series manufactured by Daicel Chemical Co., Ltd. (2021, 2021P, 2083, 2085, 3000, etc.), Epolead series, EHPE series, YD series, YDF series, YDCN series, YDB series, manufactured by Nippon Steel Chemical Co., Ltd., phenoxy resin (polyhydroxy polyether synthesized from bisphenols and epichlorohydrin, having epoxy groups at both ends; YP series, etc.), Examples include, but are not limited to, the Denacol series manufactured by Nagase ChemteX and the Epolite series manufactured by Kyoeisha Chemical Co., Ltd. Two or more of these epoxy resins may be used in combination.

The compound having an alkoxyl group in the molecule is not particularly limited as long as it has one or more alkoxyl groups in the molecule, and known compounds can be used. Representative examples of such compounds include melamine compounds, amino resins, and silane coupling agents.

The compounding amount of the compound containing either an alkoxy group or an epoxy group is usually 30% by mass or less based on the total amount of the adhesive composition, and if the content of the compound in the composition is too large, the adhesive properties impact resistance to drop tests may deteriorate. The content of the compound in the composition is more preferably 20% by mass or less. On the other hand, from the viewpoint of water resistance, the composition preferably contains the compound in an amount of 2% by mass or more, more preferably 5% by mass or more.

The adhesive composition used in the present invention preferably contains the polymerizable compound X as a curable component. Since the SP value of the polymerizable compound X is close to the SP value of transparent protective films such as unsaponified triacetyl cellulose film and acrylic film, the polymerizable compound Contribute to

The content of the polymerizable compound % or less, preferably 25% by mass or more, more preferably 35% by mass or more.

In the present invention, the compound described in the general formula (1), preferably the compound described in the general formula (1'), and more preferably the compound described in the general formulas (1a) to (1d) is used as an adhesive. It can be blended into the composition. Furthermore, in the present invention, the organometallic compound can be blended into the adhesive composition. When these compounds are blended into the adhesive composition, it is preferable because the adhesiveness with polarizers and transparent protective films may be improved. From the viewpoint of improving adhesiveness and water resistance when bonding a polarizer and a transparent protective film via an adhesive layer, the content of the compound described in the general formula (1) in the adhesive composition is 0. It is preferably from .001 to 50% by weight, more preferably from 0.1 to 30% by weight, even more preferably from 1 to 10% by weight. Further, the content of the organometallic compound in the adhesive composition is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and 1 to 5% by mass. It is even more preferable that there be.

A bubble suppressor is a compound that can lower the surface tension of the adhesive composition by blending it into the adhesive composition, and has the effect of reducing bubbles between the adhesive composition and the transparent protective film to be bonded. Examples of bubble suppressants include silicone bubble suppressants having a polysiloxane skeleton such as polydimethylsiloxane, (meth)acrylic bubble suppressants having a (meth)acrylic skeleton obtained by polymerizing (meth)acrylic acid ester, etc. When added to adhesive compositions, such as polyether-based bubble suppressants made by polymerizing vinyl ethers and cyclic ethers, and fluorine-based bubble suppressants made of fluorine-based compounds with perfluoroalkyl groups, the surface tension is reduced. It is possible to use products that have the effect of

Preferably, the bubble suppressant has a reactive group in the compound. In this case, the generation of laminar bubbles can be reduced when the polarizer and the transparent protective film are bonded together. The reactive group possessed by the bubble suppressant includes a polymerizable functional group, specifically, a radically polymerizable functional group having an ethylenic double bond such as a (meth)acryloyl group, a vinyl group, an allyl group, and a glycidyl group. Examples include cationically polymerizable functional groups such as epoxy groups, oxetane groups, vinyl ether groups, cyclic ether groups, cyclic thioether groups, and lactone groups. From the viewpoint of reactivity in the adhesive composition, a bubble suppressant having a double bond as a reactive group is preferable, and a bubble suppressant having a (meth)acryloyl group is more preferable.

When considering the effect of suppressing laminated bubbles and the effect of improving adhesion, silicone-based bubble suppressants are preferred among the bubble suppressants. Also, among the bubble suppressants, those containing a urethane bond or an isocyanurate ring structure in the main chain skeleton or side chain are preferable when considering the adhesive properties of the adhesive layer. As the silicone bubble suppressant, commercially available products can also be suitably used, such as "BYK-UV3505" (manufactured by BYK Chemie Japan Co., Ltd.), which is an acrylic group-modified polydimethylsiloxane.

In order to achieve both the adhesive strength of the resulting adhesive layer and the effect of reducing lamination bubbles, the content of the bubble suppressant should be 0.01 to 0.0% when the total amount of the adhesive composition is 100% by mass. It is preferably 6% by mass.

The adhesive composition used in the present invention can contain, in addition to the curable component related to the radically polymerizable compound, an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer. By containing the acrylic oligomer in the adhesive composition, curing shrinkage when the composition is irradiated with active energy rays and cured is reduced, making it easier to adhere the adhesive to polarizers, transparent protective films, etc. The interface stress with the body can be reduced. As a result, a decrease in adhesiveness between the adhesive layer and the adherend can be suppressed. In order to sufficiently suppress curing shrinkage of the adhesive layer, the content of the acrylic oligomer is preferably 20% by mass or less, and 15% by mass or less based on the total amount of the adhesive composition. is more preferable. If the content of the acrylic oligomer in the adhesive composition is too large, the reaction rate when the composition is irradiated with active energy rays may be drastically reduced, resulting in poor curing. On the other hand, the content of the acrylic oligomer is preferably 3% by mass or more, more preferably 5% by mass or more, based on the total amount of the adhesive composition.

Considering workability and uniformity during coating, it is preferable that the adhesive composition has a low viscosity, so it is preferable that the acrylic oligomer obtained by polymerizing a (meth)acrylic monomer also has a low viscosity. . The acrylic oligomer that has a low viscosity and can prevent curing shrinkage of the adhesive layer preferably has a weight average molecular weight (Mw) of 15,000 or less, more preferably 10,000 or less, and particularly 5,000 or less. preferable. On the other hand, in order to sufficiently suppress curing shrinkage of the adhesive layer, the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more, and 1500 or more. is particularly preferred. Specific examples of the (meth)acrylic monomer constituting the acrylic oligomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and 2-methyl- 2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl ( (Meth)acrylic acid (1-20 carbon atoms) alkyl esters such as meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and N-octadecyl (meth)acrylate; ) acrylates (e.g., cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.), aralkyl (meth)acrylates (e.g., benzyl (meth)acrylate, etc.), polycyclic (meth)acrylates (e.g., 2-isobornyl (meth)acrylate, etc.) ) acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylate, etc. ) Acrylic esters (e.g., hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), (meth)acrylics containing alkoxy or phenoxy groups Acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxy ethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic esters (e.g., glycidyl (meth)acrylate, etc.), halogen-containing (meth)acrylic esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, ) acrylate, etc.), alkylaminoalkyl (meth)acrylate (for example, dimethylaminoethyl (meth)acrylate, etc.), and the like. These (meth)acrylates can be used alone or in combination of two or more. Specific examples of acrylic oligomers include "ARUFON" manufactured by Toagosei Co., Ltd., "Actflow" manufactured by Soken Kagaku Co., Ltd., and "JONCRYL" manufactured by BASF Japan.

When the adhesive composition used in the present invention is active energy ray curable, it is preferable to use an active energy ray curable compound as the silane coupling agent, but it is not necessary to use an active energy ray curable compound. Similar water resistance can be imparted.

Specific examples of silane coupling agents include active energy ray-curable compounds such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4epoxycyclohexyl)ethyltrimethoxysilane, and 3-glyside. Xypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane Examples include silane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

Preferred are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

As a specific example of a silane coupling agent that is not curable with active energy rays, a silane coupling agent having an amino group is preferable. Specific examples of silane coupling agents having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ-amino Propylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ- (2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(2-(2-aminoethyl)aminoethyl)aminopropyltrimethoxysilane, γ- (6-aminohexyl)aminopropyltrimethoxysilane, 3-(N-ethylamino)-2-methylpropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-phenyl-γ -Aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane , N-phenylaminomethyltrimethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine and other amino group-containing silanes; N-( Examples include ketimine type silanes such as 1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine.

The silane coupling agent having an amino group may be used alone or in combination. Among these, to ensure good adhesion, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane , γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)- 1-propanamine is preferred.

The blending amount of the silane coupling agent is preferably in the range of 0.01 to 20% by weight, preferably 0.05 to 15% by weight, and 0.1 to 10% by weight based on the total amount of the adhesive composition. % is more preferable. This is because if the amount exceeds 20% by mass, the storage stability of the adhesive composition deteriorates, and if the amount is less than 0.1% by mass, the effect of water-resistant adhesion is not sufficiently exhibited.

Specific examples of silane coupling agents other than those mentioned above that are not curable with active energy rays include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and 3-mercaptopropyltrimethoxysilane. Examples include silane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatepropyltriethoxysilane, and imidazolesilane.

When the adhesive composition used in the present invention contains a compound having a vinyl ether group, it is preferable because the water-resistant adhesion between the polarizer and the adhesive layer is improved. The reason why such an effect is obtained is not clear, but it is speculated that one reason is that the vinyl ether group of the compound interacts with the polarizer, thereby increasing the adhesive force between the polarizer and the adhesive layer. Ru. In order to further improve the water-resistant adhesion between the polarizer and the adhesive layer, the compound is preferably a radically polymerizable compound having a vinyl ether group. Further, the content of the compound is preferably 0.1 to 19% by mass based on the total amount of the adhesive composition.

The adhesive composition used in the present invention can contain a compound that produces keto-enol tautomerism. For example, in an adhesive composition containing a crosslinking agent or an adhesive composition that can be used with a crosslinking agent mixed therein, an embodiment containing a compound that causes keto-enol tautomerism can be preferably employed. This can achieve the effect of suppressing excessive viscosity increase, gelation, and generation of microgels in the adhesive composition after blending the organometallic compound, and extending the pot life of the composition.

Various β-dicarbonyl compounds can be used as the compound that causes keto-enol tautomerism. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane- β-diketones such as 3,5-dione; acetoacetates such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, and tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetate Propionyl acetate esters such as tert-butyl; isobutyryl acetate esters such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonic esters such as methyl malonate and ethyl malonate; Can be mentioned. Among these, suitable compounds include acetylacetone and acetoacetic acid esters. Such compounds that produce keto-enol tautomerism may be used alone or in combination of two or more.

The amount of the compound that causes keto-enol tautomerism to be used is, for example, 0.05 parts by mass to 10 parts by mass, preferably 0.2 parts to 3 parts by mass (for example, 0.3 parts by mass) per 1 part by mass of the organometallic compound. 2 parts by mass). If the amount of the compound used is less than 0.05 parts by mass per 1 part by mass of the organometallic compound, it may be difficult to achieve sufficient effects. On the other hand, if the amount of the compound used exceeds 10 parts by mass per 1 part by mass of the organometallic compound, it may interact too much with the organometallic compound, making it difficult to develop the desired water resistance.

The adhesive composition of the present invention can contain a polyrotaxane. The above polyrotaxane includes a cyclic molecule, a linear molecule penetrating through an opening of the cyclic molecule, and a blocker placed at both ends of the linear molecule to prevent the cyclic molecule from detaching from the linear molecule. It has a group. The cyclic molecule preferably has an active energy ray-curable functional group.

The cyclic molecule is not particularly limited as long as it is a molecule in which a linear molecule is included in the opening in a skewered manner, is movable on the linear molecule, and has an active energy ray polymerizable group. Note that in this specification, "cyclic" in "cyclic molecule" means substantially "cyclic." That is, the cyclic molecule does not need to be completely closed as long as it can move on the linear molecule.

Preferred examples of the cyclic molecules include cyclic polymers such as cyclic polyethers, cyclic polyesters, cyclic polyether amines, and cyclic polyamines, and cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. It will be done. Among these, cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are preferred because they are relatively easy to obtain and many types of blocking groups can be selected. Two or more types of cyclic molecules may be mixed in the polyrotaxane or adhesive.

In the polyrotaxane used in the present invention, the cyclic molecule has an active energy ray polymerizable group. Thereby, the polyrotaxane and the active energy ray-curable component react with each other, and an adhesive whose crosslinking points are movable even after curing can be obtained. The active energy ray polymerizable group possessed by the cyclic molecule may be any group that can be polymerized with the above active energy ray curable compound, for example, a radically polymerizable group such as a (meth)acryloyl group or a (meth)acryloyloxy group. Can be mentioned.

When using cyclodextrin as the cyclic molecule, the active energy ray polymerizable group is preferably introduced into the hydroxyl group of the cyclodextrin via any suitable linker. The number of active energy ray polymerizable groups that the polyrotaxane has in one molecule is preferably 2 to 1280, more preferably 50 to 1000, even more preferably 90 to 900.

Preferably, a hydrophobic modification group is introduced into the cyclic molecule. By introducing a hydrophobic modification group, the compatibility with the active energy ray-curable component can be improved. Moreover, since it is imparted with hydrophobicity, when used in a polarizing film, it is possible to prevent water from penetrating into the interface between the adhesive layer and the polarizer, thereby further improving water resistance. Examples of hydrophobic modification groups include polyester chains, polyamide chains, alkyl chains, oxyalkylene chains, and ether chains. Specific examples include groups described in [0027] to [0042] of WO2009/145073.

A polarizing film using a resin composition containing polyrotaxane as an adhesive has excellent water resistance. The reason why the water resistance of the polarizing film is improved is not clear, but it is assumed to be as follows. In other words, the crosslinking point can move due to the mobility of the cyclic molecules of polyrotaxane (so-called pulley effect), which gives the adhesive flexibility after curing and increases its adhesion to the uneven surface of the polarizer. It is thought that as a result, water was prevented from entering the interface between the polarizer and the adhesive layer. Furthermore, it is believed that the fact that the polyrotaxane has a hydrophobic modification group imparts hydrophobicity to the adhesive, which also contributed to preventing water from entering the interface between the polarizer and the adhesive layer. The content of polyrotaxane is preferably 2% by mass to 50% by mass based on the resin composition.

<Polarizer>
In the present invention, from the viewpoint of improving optical durability in harsh environments under high temperature and high humidity, it is preferable to use a thin polarizer with a thickness of 3 μm or more and 15 μm or less, more preferably 12 μm or less, and Preferably it is 10 μm or less, particularly preferably 8 μm or less. Such a thin polarizer has less unevenness in thickness, has excellent visibility, and has less dimensional change, so it has excellent durability against thermal shock.

Note that thin polarizers generally have a low moisture content, and specifically, often have a moisture content of 15% by mass or less. Although such a thin polarizer with a low moisture content has the above-mentioned effects, it has low reactivity with the boron-containing compound or organometallic compound contained in the adhesive composition used in the present invention, and has a low reactivity with the polarizer and the organic metal compound contained in the adhesive composition used in the present invention. The effect of improving adhesion with the agent layer may not be sufficient. Therefore, in the method for producing a polarizing film of the present invention, when using a polarizer with a moisture content of 15% by mass or less, the water content is 5 to 90% when the total amount of the adhesive composition is 100% by mass. It is preferably 30-80% by weight, even more preferably 40-70% by weight.

A polarizer made of polyvinyl alcohol resin is used. As a polarizer, for example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, a partially saponified ethylene/vinyl acetate copolymer film, or a dichroic film such as iodine or a dichroic dye. Examples include polyene-based oriented films such as those obtained by adsorbing a substance and uniaxially stretched, and polyvinyl alcohol dehydrated and polyvinyl chloride dehydrochlorinated. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic substance such as iodine is suitable.

A polarizer made by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, etc., or it may be immersed in an aqueous solution such as potassium iodide. Furthermore, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. Washing a polyvinyl alcohol film with water not only removes dirt and anti-blocking agents from the surface of the polyvinyl alcohol film, but also swells the polyvinyl alcohol film to prevent uneven dyeing and other unevenness. be. Stretching may be carried out after dyeing with iodine, stretching may be carried out while dyeing, or stretching may be carried out before dyeing with iodine. Stretching can also be performed in an aqueous solution such as boric acid or potassium iodide or in a water bath.

It is preferable that the polarizer contains boric acid from the viewpoint of stretching stability and humidification reliability. Further, the boric acid content contained in the polarizer is preferably 22% by mass or less, more preferably 20% by mass or less based on the total amount of the polarizer, from the viewpoint of suppressing the occurrence of through cracks. From the viewpoint of stretching stability and humidification reliability, the boric acid content based on the total amount of the polarizer is preferably 10% by mass or more, and more preferably 12% by mass or more.

Typical thin polarizers are:
Patent No. 4751486 specification,
Patent No. 4751481 specification,
Patent No. 4815544 specification,
Patent No. 5048120 specification,
International Publication No. 2014/077599 pamphlet,
International Publication No. 2014/077636 pamphlet,
Examples include thin polarizers described in, etc., and thin polarizers obtained from the manufacturing methods described in these.

As for the thin polarizer, among the manufacturing methods that include the step of stretching and dyeing in the state of a laminate, it can be stretched to a high magnification and the polarization performance can be improved, so the method described in Patent No. 4751486 and the patent Preferably, those obtained by a manufacturing method including a step of stretching in a boric acid aqueous solution as described in Patent No. 4751481 and Japanese Patent No. 4815544, particularly those described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. Preferably, the material is obtained by a manufacturing method that includes an auxiliary step of stretching in air before stretching in a certain boric acid aqueous solution. These thin polarizers can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol resin (hereinafter also referred to as PVA resin) layer and a resin base material for stretching in the state of a laminate, and a step of dyeing. With this manufacturing method, even if the PVA resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin base material.

<Transparent protective film>
As the transparent protective film, one having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples include polycarbonate-based polymers and polycarbonate-based polymers. In addition, polyolefin polymers such as polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, ethylene-propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, and sulfone polymers. , polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above. Blends of polymers are also mentioned as examples of polymers forming the transparent protective film. The transparent protective film may contain one or more types of arbitrary appropriate additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by mass, more preferably 50 to 99% by mass, even more preferably 60 to 98% by mass, particularly preferably 70 to 97% by mass. . When the content of the thermoplastic resin in the transparent protective film is 50% by mass or less, there is a possibility that the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

In addition, as a transparent protective film, a polymer film described in JP-A-2001-343529 (WO01/37007), for example, a thermoplastic resin having (A) a substituted and/or unsubstituted imide group in the side chain, Examples include resin compositions containing thermoplastic resins having substituted and/or unsubstituted phenyl and nitrile groups in the chain. A specific example is a film of a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. A film made of a mixed extrusion product of a resin composition can be used as the film. Since these films have a small retardation and a small photoelastic coefficient, they can eliminate defects such as unevenness due to distortion of polarizing films, and also have low moisture permeability, so they have excellent humidification durability.

Further, in the present invention, it is preferable that the transparent protective film used has a moisture permeability of 150 g/m ² /24 h or less. According to this configuration, it is difficult for moisture in the air to enter the polarizing film, and a change in the moisture content of the polarizing film itself can be suppressed. As a result, curling and dimensional changes of the polarizing film caused by the storage environment can be suppressed.

The transparent protective film provided on one or both sides of the polarizer is preferably one with excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc., and particularly one with a moisture permeability of 150 g/m ² /24 h. The following is more preferable, 120 g/m ² /24 h or less is particularly preferable, and 5 to 70 g/m ² /24 h or less is even more preferable.

Examples of materials for forming the transparent protective film that satisfy the low moisture permeability include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; arylate resins; amide resins such as nylon and aromatic polyamide; polyethylene and polypropylene. , a polyolefin polymer such as an ethylene-propylene copolymer, a cyclic olefin resin having a cyclo or norbornene structure, a (meth)acrylic resin, or a mixture thereof. Among the resins, polycarbonate resins, cyclic polyolefin resins, and (meth)acrylic resins are preferred, and cyclic polyolefin resins and (meth)acrylic resins are particularly preferred.

The thickness of the transparent protective film can be determined as appropriate, but is generally preferably 5 to 100 μm in terms of strength, workability such as handleability, and thin layer property. In particular, the thickness is preferably 10 to 60 μm, more preferably 13 to 40 μm.

The transparent protective film that has a front retardation of less than 40 nm and a thickness direction retardation of less than 80 nm is usually used. The front phase difference Re is expressed as Re=(nx-ny)×d. The thickness direction phase difference Rth is expressed as Rth=(nx−nz)×d. Further, the Nz coefficient is expressed as Nz=(nx-nz)/(nx-ny). [However, the refractive indices in the slow axis direction, fast axis direction, and thickness direction of the film are respectively nx, ny, and nz, and d (nm) is the thickness of the film. The slow axis direction is the direction in which the refractive index within the film plane is maximum. ]. In addition, it is preferable that the transparent protective film has as little coloration as possible. A protective film having a retardation value in the thickness direction of -90 nm to +75 nm is preferably used. By using a film having a retardation value (Rth) in the thickness direction of -90 nm to +75 nm, coloring (optical coloring) of the polarizing film caused by the transparent protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably -80 nm to +60 nm, particularly preferably -70 nm to +45 nm.

On the other hand, as the transparent protective film, a retardation plate having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used. The frontal retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm. When a retardation plate is used as the transparent protective film, the retardation plate also functions as a transparent protective film, so that it is possible to reduce the thickness.

Examples of the retardation plate include a birefringent film formed by uniaxially or biaxially stretching a polymer material, an oriented film of a liquid crystal polymer, and a film in which an oriented layer of a liquid crystal polymer is supported by a film. The thickness of the retardation plate is also not particularly limited, but is generally about 20 to 150 μm. Examples of polymer materials include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbornene resin), or various binary or ternary copolymers and graft copolymers of these Examples include polymers and blends. These polymeric materials become oriented (stretched films) by stretching or the like.

Examples of liquid crystal polymers include various main chain type and side chain type polymers in which conjugated linear atomic groups (mesogens) that impart liquid crystal orientation are introduced into the main chain or side chain of the polymer. . Specific examples of main chain type liquid crystal polymers include, for example, nematically oriented polyester liquid crystal polymers, discotic polymers, cholesteric polymers, etc., which have a structure in which mesogenic groups are bonded to spacer portions that provide flexibility. Specific examples of side chain type liquid crystal polymers include para-substitution with a main chain skeleton of polysiloxane, polyacrylate, polymethacrylate, or polymalonate, and a spacer portion consisting of a conjugated atomic group as a side chain to impart nematic orientation. Examples include those having a mesogenic part consisting of a cyclic compound unit. These liquid crystal polymers are produced by applying a liquid crystal polymer solution onto an alignment-treated surface, such as one formed on a glass plate by rubbing the surface of a thin film made of polyimide or polyvinyl alcohol, or one coated with silicon oxide by oblique evaporation. This is done by rolling it out and heat treating it.

The retardation plate may have an appropriate retardation depending on the purpose of use, such as for the purpose of coloring due to birefringence of various wavelength plates or liquid crystal layers, or to compensate for viewing angle. It may also be one in which optical characteristics such as retardation are controlled by laminating retardation plates.

The retardation plate has the following relationships: nx=ny>nz, nx>ny>nz, nx>ny=nz, nx>nz>ny, nz=nx>ny, nz>nx>ny, nz>nx=ny. A satisfactory one is selected and used depending on the various uses. Note that ny=nz includes not only the case where ny and nz are completely the same, but also the case where ny and nz are substantially the same.

For example, for a retardation plate that satisfies nx>ny>nz, use one that satisfies the front retardation of 40 to 100 nm, the thickness direction retardation of 100 to 320 nm, and the Nz coefficient of 1.8 to 4.5. is preferred. For example, it is preferable to use a retardation plate (positive A plate) that satisfies nx>ny=nz and has a front retardation of 100 to 200 nm. For example, it is preferable to use a retardation plate (negative A plate) that satisfies nz=nx>ny and has a front retardation of 100 to 200 nm. For example, in a retardation plate that satisfies nx>nz>ny, it is preferable to use one that has a front retardation of 150 to 300 nm and an Nz coefficient of greater than 0 to 0.7. Further, as described above, for example, one that satisfies nx=ny>nz, nz>nx>ny, or nz>nx=ny can be used.

The transparent protective film can be appropriately selected depending on the liquid crystal display device to which it is applied. For example, in the case of VA (Vertical Alignment, including MVA and PVA), it is desirable that at least one transparent protective film (on the cell side) of the polarizing film has a retardation. As a specific phase difference, it is desirable that Re=0 to 240 nm and Rth=0 to 500 nm. In terms of three-dimensional refractive index, it is desirable to have nx>ny=nz, nx>ny>nz, nx>nz>ny, and nx=ny>nz (positive A plate, biaxial, negative C plate). For the VA type, it is preferable to use a combination of a positive A plate and a negative C plate, or a single biaxial film. When using polarizing films above and below a liquid crystal cell, both the upper and lower sides of the liquid crystal cell may have a retardation, or either the upper or lower transparent protective films may have a retardation.

For example, in the case of IPS (In-Plane Switching, including FFS), either one of the transparent protective films of the polarizing film may or may not have a retardation. For example, if there is no phase difference, it is desirable that there is no phase difference between the top and bottom (cell side) of the liquid crystal cell. If the liquid crystal cell has a phase difference, it is preferable that either the top or bottom of the liquid crystal cell has a phase difference (for example, if the top and bottom of the liquid crystal cell have a phase difference of nx>nz>ny). Biaxial film that satisfies the relationship, with no phase difference on the bottom, positive A plate on the top, and positive C plate on the bottom). When there is a phase difference, Re=−500 to 500 nm and Rth=−500 to 500 nm are desirable. In terms of three-dimensional refractive index, nx>ny=nz, nx>nz>ny, nz>nx=ny, nz>nx>ny (positive A plate, biaxial, positive C plate) are desirable.

The transparent protective film may further be laminated with a releasable base material in order to supplement its mechanical strength and handleability. The releasable base material can be peeled from the laminate including the transparent protective film and the polarizer before or after bonding the transparent protective film and the polarizer, during the process or in a separate process.

<Production method of polarizing film>
Each step in the method for manufacturing a polarizing film according to the present invention will be described below with reference to FIG.

<First coating process>
The first coating step is a step of coating the adhesive composition on the bonding surface of the polarizer 2 while conveying the polarizer 2 to form a wet first coating film. In addition, the easily adhesive composition may be applied to one side of the polarizer 2, or the easily adhesive composition may be applied to both sides of the polarizer 2.

<Second coating process>
The second coating step is a step of coating the adhesive composition on the bonding surface of the transparent protective film 3 while conveying the transparent protective film 3 to form a second coating film.

The polarizer 2 and the transparent protective film 3 may be subjected to surface modification treatment before the coating process. In particular, it is preferable to perform a surface modification treatment on the surface of the polarizer 2. Examples of the surface modification treatment include corona treatment, plasma treatment, excimer treatment and flame treatment, with corona treatment being particularly preferred. By performing the corona treatment, reactive functional groups such as carbonyl groups and amino groups are generated on the surface of the polarizer 2, and the adhesion with the adhesive layer is improved. In addition, the ashing effect removes foreign matter from the surface and reduces surface irregularities, making it possible to create a polarizing film with excellent appearance characteristics.

The coating machines 4 and 5 are not particularly limited, and include, for example, a reverse coater, a gravure coater (direct, reverse, and offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater, and the like.

The method of coating the adhesive composition on the bonding surface of the polarizer 2 and the method of coating the adhesive composition on the bonding surface of the transparent protective film 3 are based on the viscosity and the intended thickness of each composition. However, from the viewpoints of removing foreign substances from the surfaces of the polarizer 2 and the transparent protective film 3, coating properties, and controlling the thickness of the coating film, it is preferable to use a post-metering coating method. Specific examples of the post-metering coating method include a gravure roll coating method, a forward roll coating method, an air knife coating method, and a rod/bar coating method. Among these, the gravure roll coating method is particularly preferred from the viewpoints of removing foreign matter from the surfaces of the polarizer 2 and the transparent protective film 3, coating properties, and controlling the thickness of the coating film.

In the gravure roll coating method, various patterns can be formed on the surface of the gravure roll, such as a honeycomb mesh pattern, a trapezoidal pattern, a lattice pattern, a pyramid pattern, or a diagonal line pattern. In order to effectively prevent the appearance defects of the finally obtained polarizing film, the pattern formed on the surface of the gravure roll is preferably a honeycomb mesh pattern. In the case of a honeycomb mesh pattern, the cell volume is preferably 1 to 5 cm ³ /m ² , more preferably 2 to 3 cm ³ /m ² in order to improve the surface precision of the coated surface after coating. Similarly, in order to improve the surface precision of the coated surface after coating, the number of cell lines per inch of roll is preferably 200 to 3000 lines/inch. Further, it is preferable that the rotational speed ratio of the gravure roll to the advancing speed of the polarizer 2 and the transparent protective film 3 is 100 to 300%.

<First thickness measurement process>
The first thickness measurement step is a step of in-line measuring the thickness of the first wet coating film. As the film thickness meter 6 used for in-line measurement, it is preferable to use an optical (non-contact) film thickness meter. The optical (non-contact) film thickness meter is not particularly limited, and includes, for example, a spectral interference film thickness meter, a reflection spectroscopic film thickness meter, a confocal film thickness meter, and the like. In particular, a spectral interference type film thickness meter that can measure the thickness of the coating film over its entire width is preferred.

<Drying process>
Since the easily adhesive composition contains water, after the thickness of the wet first coating film is measured in-line, the water in the wet first coating film is removed using the dryer 7. If water remains in the dry first coating film, water will remain in the uncured adhesive layer obtained by bonding the dry first coating film and the second dry coating film together. As a result, problems such as segregation of the polymerization initiator in the uncured adhesive layer and inhibition of cationic curing of the uncured adhesive layer occur, resulting in a decrease in the adhesiveness of the adhesive layer. Therefore, a drying step is provided to remove as much water as possible from the wet first coating film. The drying step can be carried out by methods known to those skilled in the art, such as air drying, heat drying, or hot air drying.

The temperature of the dryer 7 is not particularly limited, but is preferably 15 to 40°C, more preferably 20 to 35°C. Further, the air volume of the dryer 7 is not particularly limited, but is preferably 3.8 to 30.0 m ³ /min, more preferably 6.0 to 15.5 m ³ /min per unit width (m).

<Drying degree adjustment process>
After the drying process, the thickness of the dry first coating film is measured in-line using a film thickness meter 8, and the ratio of the thickness of the wet first coating film and the thickness of the dry first coating film obtained by the in-line measurement is calculated by the following formula. By adjusting the temperature and/or air volume of the dryer 7 so as to satisfy (A), the degree of dryness of the newly formed dry first coating film is adjusted.
(Thickness of the first dry coating film/thickness of the first wet coating film) - (Content of water in the adhesive composition) ≦0.05 (A)

(Thickness of the first dry coating film/Thickness of the first wet coating film) - (Content of water in the adhesive composition) is preferably 0.04 or less, and preferably 0.03 or less. More preferably, it is 0.02 or less.

As the film thickness meter 8 used for in-line measurement, it is preferable to use an optical (non-contact) film thickness meter. The optical (non-contact) film thickness meter is not particularly limited, and examples include the above-mentioned film thickness meter. In particular, a spectral interference type film thickness meter that can measure the thickness of the dry first coating film over its entire width is preferred.

<Lamination process>
In the bonding step, the dry first coating film formed on the bonding surface of the polarizer 2 and the second coating film formed on the bonding surface of the transparent protective film 3 are bonded together to form an uncured adhesive layer. This is the process of forming. The bonding can be performed using a roll laminator 9 or the like.

<Adhesion process>
The adhesion step is a step in which the polarizer 2 and the transparent protective film 3 are bonded together to produce the polarizing film 1 via an adhesive layer obtained by curing an uncured adhesive layer.

After pasting the polarizer 2 and the transparent protective film 3 together, the uncured adhesive layer is cured by irradiation with active energy rays (electron beam, ultraviolet rays, visible light, etc.) or heating to form an adhesive layer. do. The active energy rays (electron beam, ultraviolet rays, visible light, etc.) can be irradiated from any suitable direction. Preferably, the irradiation is performed from the transparent protective film 3 side. When irradiated from the polarizer 2 side, there is a risk that the polarizer 2 will be deteriorated by the active energy rays (electron beam, ultraviolet rays, visible light, etc.).

As the irradiation conditions for electron beam irradiation, any appropriate conditions can be adopted as long as the uncured adhesive layer can be cured. For example, the acceleration voltage in electron beam irradiation is preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the uncured adhesive layer, resulting in insufficient curing. If the accelerating voltage exceeds 300 kV, the penetrating power is too strong and the transparent protective film or polarizer may cause damage. The irradiation dose is preferably 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the uncured adhesive layer will be insufficiently cured, and if it exceeds 100 kGy, it will damage the transparent protective film and polarizer, cause a decrease in mechanical strength and yellowing, and deteriorate the desired optical properties. tend not to be able to obtain it.

Electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or with a small amount of oxygen introduced. Although it depends on the material of the transparent protective film, by appropriately introducing oxygen, it is possible to create oxygen inhibition on the surface of the transparent protective film that is first hit by the electron beam, preventing damage to the transparent protective film, and preventing uncured adhesives. Only the layer can be efficiently irradiated with the electron beam.

In the method for producing a polarizing film according to the present invention, active energy rays containing visible rays in the wavelength range of 380 nm to 450 nm, particularly active energy rays that have the highest irradiation amount of visible rays in the wavelength range of 380 nm to 450 nm, are used. It is preferable. When using ultraviolet rays and visible light, and when using a transparent protective film with ultraviolet absorption ability (UV opaque transparent protective film), it absorbs light with wavelengths shorter than approximately 380 nm, so The wavelength of light does not reach the adhesive composition and contribute to its polymerization reaction. Furthermore, light with a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, causing defects such as curls and wrinkles in the polarizing film. Therefore, when using ultraviolet rays or visible light in the present invention, it is preferable to use a device that does not emit light with a wavelength shorter than 380 nm as an active energy ray generator. The ratio of illuminance to integrated illuminance in the wavelength range of 250 to 370 nm is preferably 100:0 to 100:50, more preferably 100:0 to 100:40. In the method for producing a polarizing film according to the present invention, the active energy ray is preferably a gallium-filled metal halide lamp or an LED light source that emits light in a wavelength range of 380 to 440 nm. Alternatively, ultraviolet rays such as low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, incandescent lamps, xenon lamps, halogen lamps, carbon arc lamps, metal halide lamps, fluorescent lamps, tungsten lamps, gallium lamps, excimer lasers, or sunlight A light source containing visible light can be used, and a bandpass filter can be used to block ultraviolet light having a wavelength shorter than 380 nm. In order to improve the adhesion performance of the adhesive layer between the polarizer and the transparent protective film and prevent the polarizing film from curling, a gallium-filled metal halide lamp that can block light with wavelengths shorter than 380 nm is used. It is preferable to use active energy rays obtained through a bandpass filter or active energy rays with a wavelength of 405 nm obtained using an LED light source.

It is preferable to heat the uncured adhesive layer before irradiating it with ultraviolet rays or visible light (pre-irradiation heating), in which case it is preferable to heat it to 40°C or higher, and it is preferable to heat it to 50°C or higher. More preferred. It is also preferable to heat the adhesive layer after irradiation with ultraviolet rays or visible light (post-irradiation heating), in which case it is preferable to heat it to 40°C or higher, more preferably to 50°C or higher. .

The adhesive composition used in the present invention can be suitably used particularly when forming an adhesive layer that adheres a polarizer and a transparent protective film having a light transmittance of less than 5% at a wavelength of 365 nm. Here, the adhesive composition used in the present invention contains the photoradical polymerization initiator of general formula (3) described above, and can be irradiated with ultraviolet rays through a transparent protective film having UV absorption ability to bond The agent layer can be cured and formed. Therefore, even in a polarizing film in which transparent protective films having UV absorption ability are laminated on both sides of a polarizer, the adhesive layer can be cured. However, as a matter of course, the adhesive layer can be cured even in a polarizing film laminated with a transparent protective film that does not have UV absorption ability. Note that the transparent protective film having UV absorption ability means a transparent protective film having a transmittance of less than 10% for light of 380 nm.

Examples of methods for imparting UV absorption ability to the transparent protective film include a method in which an ultraviolet absorber is contained in the transparent protective film, and a method in which a surface treatment layer containing an ultraviolet absorber is laminated on the surface of the transparent protective film.

Specific examples of ultraviolet absorbers include conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, triazine compounds, etc. .

In the method for producing a polarizing film according to the present invention, the line speed depends on the curing time of the uncured adhesive layer, but is preferably 1 to 500 m/min, more preferably 5 to 300 m/min, and still more preferably 10 to 100 m/min. It is min. If the line speed is too low, productivity is poor or damage to the transparent protective film is too great, making it impossible to produce a polarizing film that can withstand durability tests. If the line speed is too high, the uncured adhesive layer may not be sufficiently cured, and the desired adhesiveness may not be obtained.

<Adhesive layer>
The adhesive layer is formed by curing an uncured adhesive layer. The thickness of the adhesive layer is preferably 0.01 to 3 μm. If the thickness of the adhesive layer is too thin, the cohesive force of the adhesive layer will be insufficient and the peeling force will decrease, which is not preferable. If the thickness of the adhesive layer is too thick, it is not preferable because peeling is likely to occur when stress is applied to the cross section of the polarizing film, and peeling failures due to impact occur. The thickness of the adhesive layer is more preferably 0.1 to 2.5 μm, and even more preferably 0.5 to 1.5 μm.

<Optical film>
In practical use, the polarizing film of the present invention can be used as an optical film laminated with other optical layers. There are no particular limitations on the optical layer, but examples include retardation films (including 1/2 and 1/4 wavelength plates), visual compensation films, brightness enhancement films, and liquid crystals such as reflective plates and anti-transmissive plates. Examples include those that form optical layers that are sometimes used in forming display devices and the like.

As the retardation film, one having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used. The frontal retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm.

Examples of the retardation film include a birefringent film formed by uniaxially or biaxially stretching a polymeric material, an oriented film of a liquid crystal polymer, and a film in which an oriented layer of a liquid crystal polymer is supported by a film. The thickness of the retardation film is also not particularly limited, but is generally about 20 to 150 μm.

As a retardation film, the following formulas (1) to (3):
0.70<Re[450]/Re[550]<0.97...(1)
1.5×10-3<Δn<6×10-3...(2)
1.13<NZ<1.50...(3)
(In the formula, Re[450] and Re[550] are the in-plane retardation values of the retardation film measured with light with wavelengths of 450 nm and 550 nm at 23°C, respectively, and Δn is the slow phase of the retardation film. When the refractive index in the axial direction and the fast axis direction are nx and ny, respectively, nx-ny is the in-plane birefringence, and NZ is the refractive index in the thickness direction of the retardation film, An inverse wavelength dispersion type retardation film that satisfies the ratio of nx-nz, which is birefringence in the thickness direction, and nx-ny, which is birefringence in the plane, may be used.

An adhesive layer for adhering to other members such as a liquid crystal cell can also be provided on the polarizing film described above or an optical film in which at least one layer of polarizing film is laminated. The adhesive forming the adhesive layer is not particularly limited, but one whose base polymer is, for example, an acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is appropriately selected. It can be used as In particular, those having excellent optical transparency, such as acrylic pressure-sensitive adhesives, exhibiting suitable adhesive properties such as wettability, cohesiveness and adhesiveness, and having excellent weather resistance and heat resistance can be preferably used.

The adhesive layer can also be provided as a superimposed layer of different compositions or types on one or both sides of the polarizing film or optical film. Further, when provided on both sides, the adhesive layers can have different compositions, types, thicknesses, etc. on the front and back sides of the polarizing film or optical film. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, etc., and is generally 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing contamination until it is put into practical use. This can prevent contact with the adhesive layer during normal handling conditions. As a separator, other than the above thickness conditions, suitable thin materials such as plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils, and laminates thereof, silicone-based or long materials may be used as the separator. Any suitable conventional material may be used, such as one coated with an appropriate release agent such as chain alkyl, fluorine, or molybdenum sulfide.

<Image display device>
The polarizing film or optical film of the present invention can be preferably used for forming various devices such as liquid crystal display devices. The liquid crystal display device can be formed in a conventional manner. That is, a liquid crystal display device is generally formed by appropriately assembling component parts such as a liquid crystal cell, a polarizing film or an optical film, and an illumination system as necessary, and incorporating a driving circuit. There is no particular limitation except that the polarizing film or optical film according to the invention is used, and conventional methods can be used. Any type of liquid crystal cell may be used, such as a TN type, STN type, or π type.

An appropriate liquid crystal display device can be formed, such as a liquid crystal display device in which a polarizing film or an optical film is disposed on one or both sides of a liquid crystal cell, or a liquid crystal display device in which a backlight or a reflector is used in the illumination system. In that case, the polarizing film or optical film according to the invention can be placed on one or both sides of the liquid crystal cell. When providing polarizing films or optical films on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, appropriate parts such as a diffusion plate, an anti-glare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight are placed in one layer or at appropriate positions. Two or more layers can be arranged.

Examples of the present invention are described below, but the embodiments of the present invention are not limited thereto.

<Polarizer>
First, a laminate in which a 9 μm thick PVA layer was formed on an amorphous PET base material was subjected to auxiliary stretching in the air at a stretching temperature of 130°C to produce a stretched laminate, and then the stretched laminate was dyed to produce a colored laminate. The colored laminate was further drawn in boric acid water at a drawing temperature of 65 degrees, so that the total drawing ratio was 5.94 times, including a 5 μm thick PVA layer that was drawn integrally with the amorphous PET base material. An optical film laminate was produced. Through such two-step stretching, the PVA molecules of the PVA layer formed on the amorphous PET base material are highly oriented, and the iodine adsorbed by dyeing is oriented in one direction as a polyiodine ion complex. An optical film laminate containing a 5 μm thick PVA layer constituting a thin polarizer was obtained. The moisture content of the thin polarizer (PVA layer) was 10% by mass.

<Transparent protective film>
As a transparent protective film, a cycloolefin polymer film (manufactured by Nippon Zeon Co., Ltd.: ZF-14) with a thickness of 13 μm was used.

<Active energy rays>
A polarizing film was produced by irradiating ultraviolet rays as active energy rays from the transparent protective film side with a maximum illumination intensity of 500 mW/cm ² and a cumulative light amount of 800 mJ/cm ² using a UV irradiation device (high-pressure mercury lamp manufactured by Toshiba Corporation).

<Preparation of easily adhesive composition>
An easily adhesive composition was prepared by mixing 54 parts by mass of 4-hydroxybutyl acrylate, 1 part by mass of 3-acrylamidophenylboronic acid (manufactured by Junsei Kagaku Co., Ltd.), and 45 parts by mass of water, and stirring the mixture at 25°C for 10 minutes. . In addition, the content rate of water in the easily adhesive composition is 0.45.

<Preparation of adhesive composition>
ω-Carboxy-polycaprolactone (n≒2) monoacrylate (manufactured by Toagosei Co., Ltd., M5300) 5 parts by mass, isobornia acrylate 10 parts by mass, acryloylmorpholine (manufactured by Kojinsha, trade name "ACMO", SP value: 22.9) 20 parts by mass, 10 parts by mass of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (manufactured by Daicel Chemical Industries, Ltd., Celloxide 2021P), 2,4,6-trimethylbenzoyl-diphenyl-phos 1 part by mass of fin oxide (manufactured by Ciba Specialty Chemicals, TPO) and 2 parts by mass of p-phenylthiophenyldiphenylsulfonium PF ₆ salt (manufactured by San-Apro, CPI-110P) were mixed and stirred at 50°C for 1 hour. An adhesive composition was prepared by.

Example 1
On a continuous line, using a gravure roll coating method equipped with a gravure roll, the prepared easy-adhesion composition was applied to the PVA surface of the optical film laminate containing a PVA layer with a thickness of 5 μm, to an initial setting thickness of 1190 nm. A wet first coating film was continuously formed.
Meanwhile, on another continuous line, using a gravure roll coating method equipped with a gravure roll, the prepared adhesive composition was applied to the bonding surface of the transparent protective film to an initial setting thickness of 1500 nm. A second coating film was continuously formed.
Then, on a continuous line, the thickness of the first wet coating film is measured in-line using a spectral interference film thickness meter (manufactured by Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). It was measured.
Furthermore, water in the wet first coating film was removed by drying on a continuous line using a dryer at 25°C and an air flow rate of 12.5 m ³ /min per unit width (m). The thickness of the obtained dry first coating film was measured in-line using a spectral interference film thickness meter (manufactured by Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). Based on the measurement results, the temperature and air volume of the dryer were adjusted to adjust the degree of dryness of the newly formed dry first coating film. In addition, the degree of drying of the dry first coating film is adjusted by appropriately adjusting the temperature of the dryer to 22 to 28°C and the air volume to 6.0 to 15.5 m ³ /min so as to satisfy the following formula (A). I went there.
(Thickness of the first dry coating film/thickness of the first wet coating film) - (Content of water in the adhesive composition) ≦0.05 (A)
Next, using a roll machine, the dry first coating film formed on the bonding surface of the optical film laminate and the second coating film formed on the bonding surface of the transparent protective film are bonded together to form an uncured adhesive. A coating layer was formed. After that, the above-mentioned ultraviolet rays are irradiated from the bonded transparent protective film side using an active energy ray irradiation device to bond the polarizer and the transparent protective film through the adhesive layer, and then hot air dried at 70°C for 3 minutes. Then, by peeling and removing the amorphous PET base material, a polarizing film having a transparent protective film on one side of the polarizer was obtained. The line speed for bonding was 25 m/min. A polarizing film was manufactured continuously for 15 hours through the series of steps described above.

Comparative example 1
On a continuous line, using a gravure roll coating method equipped with a gravure roll, the prepared easy-adhesion composition was applied to the PVA surface of the optical film laminate containing a PVA layer with a thickness of 5 μm, to an initial setting thickness of 1195 nm. A wet first coating film was continuously formed.
Meanwhile, on another continuous line, using a gravure roll coating method equipped with a gravure roll, the prepared adhesive composition was applied to the bonding surface of the transparent protective film to an initial setting thickness of 1500 nm. A second coating film was continuously formed.
Then, on a continuous line, the thickness of the first wet coating film is measured in-line using a spectral interference film thickness meter (manufactured by Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). It was measured.
Furthermore, the water in the first wet coating film was removed by drying on a continuous line using a dryer at 25°C and an air flow rate of 12.5 m ³ /min per unit width (m). A dry first coating was formed.
Next, using a roll machine, the dry first coating film formed on the bonding surface of the optical film laminate and the second coating film formed on the bonding surface of the transparent protective film are bonded together to form an uncured adhesive. A coating layer was formed. After that, the above-mentioned ultraviolet rays are irradiated from the bonded transparent protective film side using an active energy ray irradiation device to bond the polarizer and the transparent protective film through the adhesive layer, and then hot air dried at 70°C for 3 minutes. Then, by peeling and removing the amorphous PET base material, a polarizing film having a transparent protective film on one side of the polarizer was obtained. The line speed for bonding was 25 m/min. A polarizing film was manufactured continuously for 15 hours through the series of steps described above.

Comparative example 2
On a continuous line, using a gravure roll coating method equipped with a gravure roll, the prepared easy-adhesion composition was applied to the PVA surface of the optical film laminate containing a PVA layer with a thickness of 5 μm, to an initial setting thickness of 1200 nm. A wet first coating film was continuously formed.
Meanwhile, on another continuous line, using a gravure roll coating method equipped with a gravure roll, the prepared adhesive composition was applied to the bonding surface of the transparent protective film to an initial setting thickness of 1500 nm. A second coating film was continuously formed.
Then, on a continuous line, the thickness of the first wet coating film is measured in-line using a spectral interference film thickness meter (manufactured by Ocean Optics: spectrometer "USB2000+", light source "HL-2000", fiber "OCF-103995"). It was measured.
Furthermore, the water in the first wet coating film was removed by drying on a continuous line using a dryer at 25°C and an air flow rate of 12.5 m ³ /min per unit width (m). A dry first coating was formed.
Next, using a roll machine, the dry first coating film formed on the bonding surface of the optical film laminate and the second coating film formed on the bonding surface of the transparent protective film are bonded together to form an uncured adhesive. A coating layer was formed. After that, the above-mentioned ultraviolet rays are irradiated from the bonded transparent protective film side using an active energy ray irradiation device to bond the polarizer and the transparent protective film through the adhesive layer, and then hot air dried at 70°C for 3 minutes. Then, by peeling and removing the amorphous PET base material, a polarizing film having a transparent protective film on one side of the polarizer was obtained. The line speed for bonding was 25 m/min. A polarizing film was manufactured continuously for 15 hours through the series of steps described above.

(Evaluation of adhesive strength)
The polarizing film 5 minutes and 15 hours after the start of production was cut into a size of 200 mm in parallel to the stretching direction of the polarizer and 15 mm in the orthogonal direction, and the polarizing film was bonded to a glass plate. Then, a cut was made between the transparent protective film and the polarizer with a cutter knife, and the transparent protective film and the polarizer were peeled off in a 90 degree direction using a tensilon at a peeling speed of 1000 mm/min to determine the peel strength (N/15 mm). was measured, and the adhesive strength was evaluated based on the following criteria.
〇: When the peeling force is 1N or more ×: When the peeling force is less than 1N

(Evaluation of bubbles)
The number of bubbles was counted by optical microscopic observation on both sides of the polarizing film 5 minutes and 15 hours after the start of production. The number of bubbles was counted in a 5 cm x 5 cm area, and the case where the total number of bubbles on both sides was less than 3 was evaluated as ○, and the case where it was 3 or more was evaluated as ×.

From Table 2, in Example 1, since the drying degree adjustment step was performed, fluctuations in the drying degree of the dry first coating film were suppressed during continuous production, and the adhesive strength was excellent even 15 hours after the start of production. It can be seen that a polarizing film can be stably obtained. Moreover, it can be seen that the generation of bubbles in the obtained polarizing film is suppressed. On the other hand, in Comparative Examples 1 and 2, since the drying degree adjustment step was not performed, the drying degree of the dry first coating film greatly fluctuated during continuous production. It can be seen that the adhesive strength of the adhesive layer was low because the cationic polymerization reaction was inhibited by the water remaining in the film.

The polarizing film of the present invention can be used alone or as an optical film in which the films are laminated in an image display device such as a liquid crystal display (LCD), an organic EL display, a CRT, or a PDP.

1: Polarizing film 2: Polarizer 3: Transparent protective film 4, 5: Coating machine 6, 8: Film thickness meter 7: Dryer 9: Roll laminator

Claims (7)

A method for producing a polarizing film, in which a transparent protective film is provided on at least one surface of a polarizer via an adhesive layer,
A first coating step of coating an easily adhesive composition containing water and a hydrophilic monomer on the bonding surface of the polarizer while conveying the polarizer to form a wet first coating film;
A second step of forming a second coating film by applying an adhesive composition containing a radically polymerizable compound and a cationic polymerizable compound to the bonding surface of the transparent protective film while conveying the transparent protective film. coating process,
a first thickness measurement step of in-line measuring the thickness of the wet first coating film;
After the first thickness measurement step, a drying step of removing water in the wet first coating film using a dryer to form a dry first coating film;
After the drying step, a second thickness measurement step of in-line measuring the thickness of the dry first coating film;
Adjusting the temperature and/or air volume of the dryer so that the ratio of the thickness of the wet first coating film and the thickness of the dry first coating film obtained by the in-line measurement satisfies the following formula (A). A drying degree adjusting step of adjusting the drying degree of the newly formed dry first coating film,
A paste that forms an uncured adhesive layer by laminating the dry first coating film formed on the pasting surface of the polarizer and the second coating film formed on the pasting surface of the transparent protective film. A method for producing a polarizing film, comprising: a bonding step; and an adhesion step of bonding the polarizer and the transparent protective film via the adhesive layer obtained by curing the uncured adhesive layer.
(Thickness of the first dry coating film/thickness of the first wet coating film) - (Content of water in the adhesive composition) ≦0.05 (A) The easily adhesive composition has the following general formula (1):

^A compound represented ^by , or a heterocyclic group) and/or an organometallic compound having an MO bond (M is silicon, titanium, aluminum, or zirconium, and O is an oxygen atom) in the structural formula. 1. The method for producing a polarizing film according to 1. The compound represented by the general formula (1) is represented by the following general formula (1')

The method for producing a polarizing film according to claim 2, which is a compound represented by (wherein Y is an organic group, and X, R ¹ and R ² are the same as above). The reactive group possessed by the compound represented by the general formula (1) is an α,β-unsaturated carbonyl group, a vinyl group, a vinyl ether group, an epoxy group, an oxetane group, an amino group, an aldehyde group, a mercapto group, and a halogen group. The method for producing a polarizing film according to claim 2 or 3, wherein the reactive group is at least one kind selected from the group consisting of groups. The method for producing a polarizing film according to claim 1, wherein the polarizer has a moisture content of 15% by mass or less. The method for producing a polarizing film according to any one of claims 1 to 5, wherein the first coating step and the second coating step are coating steps using a post-metering coating method. 7. The method for producing a polarizing film according to claim 6, wherein the post-metering coating method is a gravure roll coating method using a gravure roll.

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