JP4849115B2 - Laminated body, liquid crystal display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a laminate in which protective films are laminated on both surfaces of a polarizing film, and more particularly to a laminate suitable as a polarizing film and a method for producing the same.

Polarizing films make use of various functions such as reflected light removal and light lockability, for example, sunglasses, camera filters, sports goggles, lighting gloves, anti-glare headlights for automobiles, light-shielding window glass, light quantity adjustment filters, fluorescence It is used in a wide range of fields such as display contrasters, translucent continuously changing plates, and polarizing films for microscopes. Recently, it has been used in liquid crystal displays (LCDs) and its functionality has been highlighted.
By the way, LCDs are rapidly spreading in notebook computers, mobile phones, car navigation systems, flat TVs and the like. And since it is lightweight and thin, it is used for portable use outdoors, and its use environment is severe. For this reason, there is a strong demand for polarizing films to improve durability and stabilize optical performance.

The polarizing film is composed of at least a thin film type polarizing film having a polarizing function and a protective layer for ensuring the durability and mechanical strength of the polarizing film. As the protective layer, a solution cast film of cellulose triacetate (hereinafter abbreviated as TAC) with low birefringence and good appearance is mainly used.
However, as LCDs become thinner, larger, and have higher brightness, the durability of polarizing films has been demanded more than ever, and the TAC protective layer has sufficient moisture resistance to satisfy it. There was a problem of not having.
Recently, it has been proposed to use a thermoplastic saturated norbornene resin sheet having excellent moisture resistance instead of TAC as a protective layer of a polarizing film.

  An object of the present invention is to provide a laminate having a polarizing function excellent in durability and mechanical strength under a severe use environment, and a method for producing the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the thermoplastic norbornene resin film has a thickness in a specific range, a moisture permeability of a specific value or less, and a maximum in-plane letter. A film having a foundation of a specific value or less is laminated as a protective layer on one surface of the polarizing film, and the other surface is a triacetyl cellulose film having a specific thickness and a moisture permeability of a specific value or less. It was found that the polarizing film formed was excellent in durability and mechanical strength under harsh use environments, and the present invention was completed based on this finding.

Thus, according to the present invention,
1. On one surface of the polarizing film (C), a resin film having a thickness of 5 to 200 μm, a moisture permeability of 0.3 to 2.9 g / m ² · 24 h, and an in-plane maximum retardation value of 4 nm or less A) is laminated, and a laminate in which a resin film (B) having a thickness of 20 to 200 μm and a moisture permeability of 50 to 1,500 g / m ² · 24 h is laminated on the other surface,
2. ^2. The laminate according to 1, wherein the resin film (A) has a moisture permeability of 0.6 to 2.9 g / m ² · 24 h.
3 . The laminate according to 1 or 2 , further comprising a vinyl alcohol polymer adhesive layer between the film (A) and the polarizing film (C) and between the film (B) and the polarizing film (C),
4 . The laminate according to any one of 1 to 3, wherein the film (A) comprises an alicyclic structure-containing polymer resin as a main component,
5 . The laminate according to any one of 1 to 4 , wherein the film (B) has triacetyl cellulose as a main component,
6 . One surface of the film (A) or one surface of the polarizing film (C) having a thickness of 5 to 200 μm, a moisture permeability of 0.3 to 2.9 g / m ² · 24 h, and an in-plane maximum retardation value of 4 nm or less And at least one surface of the film (B) having a thickness of 20 to 200 μm and a moisture permeability of 50 to 1,500 g / m ² · 24 h, or at least one surface of the polarizing film (C) other than the above. Applying a polymer solution, and then laminating the film (A) and the film (B) on both sides of the polarizing film (C), respectively, and maintaining the temperature at 2 to 150 ° C. for 0.5 to 200 hours The manufacturing method of the laminated body of 3 containing,
Are provided respectively.

  According to the present invention, it is possible to obtain a polarizer that is excellent in durability under harsh usage environments and stability in optical performance.

The laminate of the present invention has a thickness of 5 to 200 μm, a moisture permeability of 0.3 to 40 g / m ² · 24 h on one surface of the polarizing film (C), and an in-plane maximum retardation value of 4 nm or less. A certain resin film (A) is laminated, and a resin film (B) having a thickness of 20 to 200 μm and a moisture permeability of 50 to 1,500 g / m ² · 24 h is laminated on the other surface. To do.

The thickness of the resin film (A) is preferably 10 to 100 μm, more preferably 20 to 80 μm. When the thickness is less than 5 μm, the mechanical strength as a protective film is lowered, and warpage or the like is likely to occur when the laminate is placed in a high temperature and high humidity environment. When the thickness exceeds 200 μm, the light transmittance of the protective film is lowered, and further, the adhesive is not sufficiently dried when the respective films are bonded, and the durability of the polarizing film is lowered. Therefore, when the thickness of the film (A) is in the above range, a laminate excellent in mechanical strength and durability can be obtained.
The film (A) has a moisture permeability of preferably 0.6 to 20 g / m ² · 24 h, more preferably 1 to 10 g / m ² · 24 h. If the moisture permeability is too low, drying of the adhesive is insufficient as described above, and if it is too high, moisture absorption of the polarizing film in the use environment increases, and the durability of the polarizing film decreases in any case. Is in the above range, the durability of the polarizing film is improved. The moisture permeability is a value measured at a temperature of 40 ° C. and a humidity of 90% using a cup method according to JIS Z0280.
Further, the film (A) has an in-plane maximum retardation (Re _max ) of preferably 3 nm or less, more preferably 2 nm or less. When Re _max is in the above range, the optical performance when the laminate is used as a polarizing film is improved.

  The material constituting the film (A) used in the present invention may be a resin that satisfies the above characteristics when formed into a film having a thickness of 5 to 200 μm, but is a thermoplastic resin from the viewpoint of mechanical strength and molding processability. Preferably there is. Examples of such a thermoplastic resin include polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polymethylpentene, polysulfone, and alicyclic structure-containing polymer resin. Can satisfy alicyclic structure containing polymer resin.

The alicyclic structure-containing polymer resin contains an alicyclic structure in the repeating unit of the polymer, and the alicyclic structure may be in either the main chain or the side chain. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability. The number of carbon atoms constituting the alicyclic structure is usually 4 to 30, preferably 5 to 20, and more preferably 5 to 15. When the number of carbon atoms constituting the alicyclic structure is in this range, a protective layer excellent in heat resistance and flexibility can be obtained.
The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin may be appropriately selected according to the purpose of use, but is usually 50% by weight or more, preferably 70% by weight or more, more preferably Is 90% by weight or more. If the proportion of the repeating unit having an alicyclic structure is too small, the heat resistance is undesirably lowered. In addition, repeating units other than the repeating unit which has an alicyclic structure in an alicyclic structure containing polymer resin are suitably selected according to the intended purpose.

  Specific examples of the alicyclic structure-containing polymer resin include (1) a norbornene polymer, (2) a polymer of a monocyclic olefin, (3) a polymer of a cyclic conjugated diene, and (4) a vinyl alicyclic ring. And hydrides of (1) to (4). Among these, from the viewpoints of heat resistance, mechanical strength, and the like, norbornene polymer hydrides, vinyl alicyclic hydrocarbon polymers, and hydrides thereof are preferable.

The norbornene polymer is a polymer of monomers mainly composed of norbornene monomers such as norbornene and derivatives thereof, tetracyclododecene and derivatives thereof, dicyclopentadiene and derivatives thereof, methanotetrahydrofluorene and derivatives thereof, and the like. Specifically, (1) a ring-opening polymer of a norbornene-based monomer, (2) a ring-opening copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization, and (3) an attachment of a norbornene-based monomer. Examples thereof include addition polymers, addition copolymers of (4) norbornene monomers and other monomers copolymerizable therewith, and hydrogenated products of (1) to (4). Among these, from the viewpoints of heat resistance, mechanical strength, and the like, a ring-opening polymer hydride of a norbornene monomer is most preferable.
The molecular weight of the norbornene-based polymer, the polymer of the monocyclic olefin or the polymer of the cyclic conjugated diene is appropriately selected according to the purpose of use, but the cyclohexane solution (toluene solution if the polymer resin does not dissolve) The polyisoprene or polystyrene-converted weight average molecular weight measured by gel permeation chromatography is usually 5,000 to 500,000, preferably 8,000 to 200,000, more preferably 10,000 to 100,000. When the thickness is in the range, the mechanical strength of the film (A) and the moldability are highly balanced, which is preferable.
The vinyl alicyclic hydrocarbon polymer is a polymer having a repeating unit derived from vinylcycloalkane or vinylcycloalkene. For example, a cycloalkane having a vinyl group such as vinylcyclohexene or vinylcyclohexane or a cyclohexane having a vinyl group. Alkenes, that is, polymers of vinyl alicyclic hydrocarbon compounds and hydrogenated products thereof; hydrogenated products of aromatic ring portions of polymers of vinyl aromatic hydrocarbon compounds such as styrene and α-methylstyrene; and the like can be used. Vinyl alicyclic hydrocarbon polymers are random copolymers and block copolymers of vinyl alicyclic hydrocarbon compounds and vinyl aromatic hydrocarbon compounds with other monomers copolymerizable with these monomers. Copolymers such as polymers and their hydrides may also be used. Examples of the block copolymer include diblock, triblock, or more multiblock and gradient block copolymers, but are not particularly limited.
The molecular weight of the vinyl alicyclic hydrocarbon polymer is appropriately selected according to the purpose of use, but it is determined by a gel permeation chromatographic method using a cyclohexane solution (a toluene solution when the polymer resin does not dissolve). When the weight average molecular weight in terms of isoprene or polystyrene is usually in the range of 10,000 to 300,000, preferably 15,000 to 250,000, more preferably 20,000 to 200,000, It is suitable because the mechanical strength and moldability are well balanced.

  The glass transition temperature (Tg) of the resin that is the main component of the film (A) may be appropriately selected according to the purpose of use, but is usually 80 ° C. or higher, preferably 100 ° C. to 250 ° C., more preferably 120 ° C. It is the range of ° C to 200 ° C. Within this range, heat resistance and moldability are highly balanced and suitable.

In the present invention, the above resin can be molded to obtain a film (A).
As a method for forming the film (A), for example, a heat melt molding method or a solution casting method can be used. The heat-melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method, a stretch molding method, etc. Among these methods, mechanical strength, surface In order to obtain a film excellent in accuracy and the like, the extrusion molding method, the inflation molding method, and the press molding method are preferable, and the extrusion molding method is most preferable. The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of the heat-melt molding method, the cylinder temperature is usually 150 to 400 ° C, preferably 200 to 350 ° C, more preferably 230 to 330 ° C. It is set as appropriate within the range. If the resin temperature is too low, fluidity will deteriorate, causing shrinkage and distortion in the film. If the resin temperature is too high, voids and silver streaks will occur due to thermal decomposition of the resin, and the film will turn yellow. Defects may occur.

In the present invention, in order to set the in-plane maximum retardation (Re _max ) of the film (A) to 4 nm or less in the above thickness range, for example, when the film is formed by extrusion, the temperature of the cast roll is used. And control the peripheral rotation speed, film temperature and the like. Specifically, when an alicyclic structure-containing polymer resin is used, the temperature of each roll when using a plurality of cast rolls is preferably controlled within Tg ± 30 ° C. of the resin used. The speed ratio of the roll is a ratio of the peripheral speed (R1) of the first roll and the peripheral speed (R2) of the second roll, and R2 / R1 = 0.9 to 1.0 is preferable. In this case, it is preferable that the variation in the peripheral speed of each roll is within 0.1%.
The ratio (drawing rate) between the target film thickness and the die slip opening degree is preferably 0.05 to 0.8 in terms of the film thickness / die slip opening degree, and is 0.08. -0.4 is more preferable.

  The film (A) may contain additives that can be generally blended into a plastic film, if necessary, in addition to the above-described resin. Examples of such additives include antioxidants, heat stabilizers, light-resistant stabilizers, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, fillers, and the like, the content of which is the object of the present invention. It can be selected within a range that does not damage.

  The film (A) has a surface wetting tension of preferably 40 mN / m or more, more preferably 50 mN / m or more, and even more preferably 55 mN / m or more. When the surface wetting tension is in the above range, the adhesive strength between the film (A) and the polarizing film (C) is improved. In order to adjust the surface wetting tension, for example, corona discharge treatment, ozone spraying, ultraviolet irradiation, flame treatment, chemical treatment, and other known surface treatments can be performed.

Film (B)
The thickness of the film (B) is preferably 30 to 150 μm, more preferably 40 to 100 μm. When the thickness of the film (B) is less than 20 μm, the mechanical strength of the laminate is reduced, and when it exceeds 200 μm, warpage is likely to occur when the laminate is placed in a high temperature and high humidity environment, and the light transmittance is also increased. descend. Therefore, when the thickness of the film (B) is in the above range, a laminate excellent in durability, mechanical strength and optical performance can be obtained. Further moisture permeability of the film (B) is preferably 100~1,000g ^/ m 2 · 24h, more preferably 150~800g ^/ m 2 · 24h. If the moisture permeability is too low, drying of the adhesive that adheres the film (B) to the polarizing film (C) becomes insufficient, and if the moisture permeability is too high, the polarizing film absorbs moisture in the usage environment. Therefore, when the moisture permeability is in the above range, the reliability when the laminate is used as a polarizing film is improved.
The material constituting the film (B) may be a resin having a moisture permeability of the above range when the film is in the above film thickness range, and examples thereof include ethylene-vinyl alcohol copolymer and cellulose ester. . Examples of the acetylated cellulose ester include diacetyl cellulose and triacetyl cellulose. Of these, triacetyl cellulose is most preferable from the viewpoints of transparency, mechanical strength, and the like. The film (B) is subjected to alkali saponification treatment, plasma treatment, glow discharge treatment, corona discharge treatment, high frequency treatment, electron beam treatment, etc., in order to improve the adhesion to the polarizing film (C). It doesn't matter.

Polarizing film (C)
The polarizing film (C) used for this invention will not be specifically limited if it has a function as a polarizer. For example, (1) vinyl alcohol polymer (PVA) / iodine polarizing film, (2) PVA / dye polarizing film in which dichroic dye is adsorbed and oriented on PVA film, (3) dehydrated from PVA film A polyene polarizing film in which a polyene is formed by inducing a reaction or by dehydrochlorination reaction of a polyvinyl chloride film, (4) The surface and / or the inside of a PVA film comprising a modified PVA containing a cationic group in the molecule And a polarizing film having a dichroic dye. From the viewpoint of the initial polarizing performance of the polarizing film, (1) a PVA / iodine polarizing film is preferable, and from the viewpoint of heat resistance, (2) a PVA / dye polarizing film is preferable.
The manufacturing method of the polarizing film is not particularly limited. For example, (1) a method of adsorbing iodine ions after stretching a PVA film, (2) a method of stretching after dyeing a PVA film with a dichroic dye, (3) a dichroic dye after stretching a PVA film Well-known methods such as a method of dyeing, (4) a method of stretching a dichroic dye on a PVA-based film and then stretching, and (5) a method of stretching a PVA-based film and then printing a dichroic dye.
For example, in the method of (1), more specifically, iodine is dissolved in a potassium iodide solution to form iodine ions, the ions are adsorbed on a PVA film and stretched, and then dissolved in a 1 to 4% boric acid aqueous solution. A polarizing film is produced by dipping at a bath temperature of 30 to 40 ° C. More specifically, in the method of (2), the PVA film is immersed in a boric acid aqueous solution in the same manner as in (1), and then stretched about 3 to 7 times in a uniaxial direction, and 0.05 to 5% dichroism. A polarizing film is produced by immersing the dye in an aqueous dye solution at a bath temperature of 30 to 40 ° C. to adsorb the dye, drying at 80 to 100 ° C., and heat setting.

The laminate of the present invention is obtained by laminating the film (A) on one surface of the polarizing film (C) and the film (B) on the other surface. Lamination of the polarizing film (C) and the film (A), and the polarizing film (C) and the film (B) may be simple superposition, but from the viewpoint of mechanical strength and durability, it is based on adhesion. Preferably there is. Specific examples of the bonding method include a method using an adhesive, a method using welding, and a method using coextrusion. In the present invention, an adhesive method is preferred from the viewpoint of adhesive strength, durability, and the like.
In the case of using the above adhesive, the adhesive layer that can be interposed between the polarizing film (C) and the film (A) includes a layer made of a vinyl alcohol polymer, a layer of silicone adhesive, a urethane type Examples include an adhesive layer, an adhesive layer containing a conjugated diene polymer having a cyclized structure therein or a hydrogenated product thereof, reliability as a polarizing film, mechanical strength, optical properties, etc. From the above viewpoint, a layer made of a vinyl alcohol polymer or a layer of an adhesive containing a conjugated diene polymer having a cyclized structure therein or a hydrogenated product thereof is preferred, and a layer made of a vinyl alcohol polymer is most preferred.

  A vinyl alcohol polymer (sometimes referred to as PVA) is a generally known polymer. This PVA is obtained by, for example, polymerizing a vinyl monomer mainly composed of a vinyl ester monomer by a conventionally known method to produce a vinyl ester polymer (that is, a vinyl ester monomer homopolymer, two or more kinds). A vinyl ester monomer copolymer and a copolymer of a vinyl ester monomer and another ethylenically unsaturated monomer), and then saponifying the vinyl ester polymer by a conventional method. Is obtained. The saponification degree of the PVA used in the present invention is preferably 70 to 99%, and the polymerization degree is 200 to 3000. The PVA used in the present invention may be one in which, for example, acrylic acid, crotonic acid, itaconic acid and the like are copolymerized to a few mol% within a range that does not impair the object of the present invention. Further, a compound having an epoxy group, a carbonyl group, a silanol group, a thiol group, or the like may be modified by graft addition or the like.

In the adhesive layer, for example, a curing agent; a coupling agent such as a silane coupling agent and a titanium coupling agent; terpene resin, phenol resin, terpene-phenol resin, rosin resin, xylene Tackifiers such as resins; inorganic fillers such as calcium carbonate, clay, titanium oxide, and carbon black; thixotropic agents such as aerosil and disbaron; UV absorbers, antioxidants, heat stabilizers, hydrolysis stabilizers A stabilizer such as may be contained.
The thickness of the adhesive layer is preferably from 0.01 to 20 μm, more preferably from 0.05 to 10 μm. When the thickness is less than 0.01 μm, it becomes difficult to control the thickness, and when it exceeds 20 μm, the durability of the polarizing film is lowered.

  The manufacturing method of the laminated body of the present invention using an adhesive includes at least one surface of one surface of the film (A) or the polarizing film (C), and one surface of the film (B) or the polarizing film (C) other than the above. A solution containing the component of the adhesive layer is applied to at least one surface of the film, and then the film (A) and the film (B) are bonded to both surfaces of the polarizing film (C).

The method is described in more detail below.
(1) The component of the adhesive layer is applied to at least one surface of the film (A) or at least one surface of the polarizing film (C) and at least one surface of the film (B) or the polarizing film (C) other than the above. A method in which a solution containing the coating is applied, the film (A) and the film (B) are bonded to both sides of the polarizing film (C) before the coating film is dried, and then the solvent is removed and bonded (so-called wet lamination). ,as well as,
(2) The component of the adhesive layer is applied to at least one surface of the film (A) or at least one surface of the polarizing film (C) and at least one surface of the film (B) or the polarizing film (C) other than the above. Apply the solution, and then remove the solvent and dry the coating film. Then, attach the film (A) and the film (B) on both sides of the polarizing film (C), pressurize and / or heat, etc. (So-called dry lamination).
In the case of wet lamination (1), the solution is applied or dropped onto a polarizing film or / and film using a Meyer bar, gravure coater, micro gravure coater, etc., and the solvent is heated while laminating the laminate with, for example, two rolls. Remove by etc.
In the case of dry lamination (2), the solution is applied to the polarizing film and / or film with a bar coater, roll coater, gravure coater, etc., and the solvent in the coating film is removed using means such as passing through a drying furnace. .

In the above, the type of the adhesive layer to be interposed and the method of laminating the film on the polarizing film (C) include the polarizing film (C) and the film (A), and the polarizing film (C) and the film (B). May be different from each other.
In this invention, when bonding a film (A) and a film (B) to a polarizing film (C), it is preferable to manufacture a laminated body by wet lamination using the solution of a vinyl alcohol polymer. In that case, the viscosity of the vinyl alcohol polymer solution used is preferably in the range of 10 to 20,000 cP (centipoise), more preferably 100 to 12,000 cP. When the pressure is less than 10 cP, the solution flows excessively out of the laminate due to pressurization during lamination, and the thickness of the adhesive layer is reduced. On the other hand, when the pressure exceeds 20,000 cP, the coating property is deteriorated.
In wet lamination, it is preferable to use water as a solvent because the adhesive strength between the layers of the laminate is excellent. Furthermore, the conventional manufacturing equipment for polarizing plates using a triacetyl cellulose layer can be effectively used as it is as an adhesive equipment. .

  In any of wet lamination and dry lamination, lamination of each film and the polarizing film (C) may be performed by any known means, but is preferable because it is easy to use a nip roll and is excellent in productivity. . As the nip roll, a rubber roll and a metal roll, or a rubber roll and a rubber roll can be combined. The pressure at the time of lamination is usually 1 to 100 kgf / cm, preferably 3 to 30 kgf / cm in terms of nip line pressure.

The laminate obtained above is cured, that is, maintained for a certain time at a certain temperature, thereby improving the adhesive strength between the polarizing film (C) and each film, the durability of the polarizing film, and in a high temperature and high humidity environment. Warpage of the laminate can be reduced. The curing conditions are such that the temperature is preferably 2 to 150 ° C, more preferably 20 to 80 ° C, and the holding time is 0.5 to 200 hours, preferably 48 to 100 hours. When the curing temperature and holding time are within the above ranges, a polarizing film excellent in durability, optical performance and the like can be obtained.
Moreover, when an adhesive layer contains a hardening | curing agent, the adhesive strength of an adhesive layer and each layer, durability of an adhesive layer, mechanical strength, etc. can be improved by heating and hardening an adhesive layer. The heating temperature of the coating film, the curing temperature, each time, etc. are set in an optimum range depending on the kind of the curing agent.
Moreover, after bonding each film and a polarizing film (C) through an adhesive layer, it is preferable to control the thickness of an adhesive layer by applying a pressure to this.

  Since the laminate of the present invention obtained by the above method has a polarizing function, for example, sunglasses, camera filters, sports goggles, illumination gloves, automotive antiglare headlights, light shielding window glass, light amount adjustment filters, The present invention can be used in a wide range of fields such as a fluorescent display contraster, a light transmission continuous change plate, and a polarizing film for a microscope. Furthermore, since the laminate of the present invention is excellent in optical performance and durability, it can be suitably used particularly for a polarizing film and a polarizing plate of a liquid crystal display (LCD). In particular, when used as a polarizing film or a polarizing plate, the film (A) functions as a protective film. The polarizing film and the protective film in the polarizing plate have a function of maintaining the durability of the polarizing film, particularly the degree of polarization, and are provided on at least one side of the polarizing film (preferably the LCD side surface for LCDs). There is a need.

Hereinafter, although a manufacture example, an Example, and a comparative example are given and this invention is demonstrated more concretely, the scope of the present invention is not limited to these examples.
In these examples, [parts] and [%] are based on weight unless otherwise specified. Moreover, the measuring method of various physical properties is as follows.

(1) The glass transition temperature (Tg) was measured with a differential scanning calorimeter (DSC method).
(2) Unless otherwise specified, the molecular weight was measured as a polyisoprene equivalent value measured by gel permeation chromatography (GPC) using cyclohexane as a solvent.
(3) The moisture permeability of the films (A) and (B) was measured at a temperature of 40 ° C. and a humidity of 90% using the cup method of JIS Z0208.
(4) The thickness of each film was measured with a dial-type thickness gauge.
(5) The in-plane maximum retardation of the film (A) was measured with a Belek compensator having a wavelength of 550 nm.
(5) Regarding the mechanical strength of the polarizing film, the following 300 mm square laminated film was alternately folded 500 times on both sides along the diagonal line, and the film was checked for microcracks using an optical microscope. Evaluation was performed as follows.
A: No change B: Slight microcracks are generated at the end of the film, but there is no practical problem.
×: Microcracks are generated along the bent part (6) Durability test The laminated film is sequentially exposed to the following environment, and the appearance of the laminated film is visually observed for transparency, haze generation, discoloration, warpage, and the like. And evaluated.
(1) High temperature environment: 80 ° C, humidity 50%, 500 hours
(2) High temperature and high humidity environment 1: Temperature 60 ° C, humidity 90%, 500 hours
(3) High-temperature and high-humidity environment 2: temperature 80 ° C, humidity 90%, 100 hours
(4) Low temperature environment: -30 ° C, humidity 10%, 500 hours
(5) Water-resistant environment: A wet tissue is placed on the laminated film at a temperature of 80 ° C. and a humidity of 90% and left for 30 minutes.

[Production Example 1]
In a nitrogen atmosphere, 500 parts of dehydrated cyclohexane, 0.82 part of 1-hexene, 0.15 part of dibutyl ether and 0.30 part of triisobutylaluminum were mixed in a reactor at room temperature, and then kept at 45 ° C. 80 parts of tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (dicyclopentadiene, hereinafter abbreviated as DCP), 1,4-methano-1,4,4a, 9a-tetrahydrofluorene (Hereinafter abbreviated as MTF) 50 parts, and tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ] -dodec-3-ene (hereinafter abbreviated as TCD) 70 parts of a norbornene monomer mixture and 40 parts of tungsten hexachloride (0.7% toluene solution) were continuously added over 2 hours. And polymerized. To the polymerization solution, 1.06 part of butyl glycidyl ether and 0.52 part of isopropyl alcohol were added to deactivate the polymerization catalyst and stop the polymerization reaction.

  Next, 270 parts of cyclohexane is added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and further 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) is added as a hydrogenation catalyst. The mixture was heated to 200 ° C. while being pressurized and stirred, and then reacted for 4 hours to obtain a reaction solution containing 20% of a DCP / MTF / TCD ring-opening polymer hydrogenated polymer. After removing the hydrogenation catalyst by filtration, a soft polymer (manufactured by Kuraray Co., Ltd .; Septon 2002) and an antioxidant (manufactured by Ciba Specialty Chemicals Co., Ltd .; Irganox 1010) were both added to 0.1 parts per 100 parts of the polymer. Part was added to the resulting solution and dissolved. Next, while removing cyclohexane and other volatile components from the solution using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), the hydrogenated polymer is extruded in the form of a strand from the extruder in a molten state, recovered and pelletized after cooling. did. When the copolymerization ratio of each norbornene monomer in the polymer was calculated from the composition of residual norbornenes in the solution after polymerization (by gas chromatography method), it was almost charged at DCP / MTF / TCD = 40/25/35. The content of repeating units equal to the composition and having no norbornane ring structure was 65%. This hydrogenated ring-opened polymer had a weight average molecular weight (Mw) of 35,000, a hydrogenation rate of 99.9%, and a Tg of 134 ° C.

[Example 1]
The pellet obtained in Production Example 1 was dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated to remove moisture, and then a T-die type having a resin melt kneader equipped with a 65 mmφ screw. Using a film melt extrusion molding machine, a film (A) having a thickness of 40 μm was extrusion molded under molding conditions of a molten resin temperature of 220 ° C. and a T-die width of 300 mm.
The moisture permeability of the film (A) was 2.9 g / cm ² · 24 h, and the in-plane maximum retardation value was 1.9 nm.
The obtained film was cut in a length direction of 300 mm, and the corona discharge treatment was performed on the surface in the air with a discharge amount of 100 W / m ² · min. The wetting tension on the surface of the film (A) was 70 mN / m or more.
A 10% aqueous solution of a polyvinyl alcohol polymer (manufactured by Kuraray Co., Ltd .: PVA203, degree of saponification of 86.5-89.5%, average degree of polymerization of 300) is dropped on the surface of the film (A), and then the film (A ) Was bonded to an unstained PVA biaxially stretched film (C) of the same size (Nippon Gosei Chemical Co., Ltd. polarizing film: Boblon # 140 (film thickness: 14 μm)).
Next, one surface of a film (B) (moisture permeability of 270 g / cm ² · 24 h) made of triacetyl cellulose having the same size as the film (A) and a thickness of 80 μm is saponified with a 10% aqueous solution of caustic soda. Then, a 10% aqueous solution of the same polyvinyl alcohol polymer was dropped. Next, the laminated film obtained by bonding the polarizing film (C) and the film (A) and the film (B) were bonded so that the aqueous solution application surface and the polarizing film side surface face each other.
The three-layer laminated film was placed on a roll laminator and pressed before the PVA aqueous solution was dried. Next, the laminated film was left at 40 ° C. for 72 hours to completely adhere each layer. The thickness of the adhesive layer was 1 μm. The obtained laminated film was evaluated by performing the above durability test. The results are listed in Table 1.

[Example 2]
A laminate was produced in the same manner as in Example 1 except that the thicknesses of the film (A) and the film (B) were changed to 100 μm and 50 μm, respectively. Remax of the film (A) was 3.5 nm. Evaluation similar to Example 1 was performed about this laminated body. The mechanical strength and transparency of the laminated film were slightly inferior to the mechanical strength and transparency of the laminated body of Example 1, but were at a satisfactory level with no practical problems. The results are listed in Table 1.

Example 3
A laminated film was produced and evaluated in the same manner as in Example 2 except that the standing condition of the laminated film after pressure bonding was changed to 20 ° C. for 4 hours. Although the transparency (light transmittance) of the film was slightly lower than that of Example 1, they were all good at a practical level, and there was no change in haze or discoloration. The results are listed in Table 1.

[Comparative Example 1]
As shown in Table 1, a laminated film was produced and evaluated in the same manner as in Example 1, except that the film (B) having a thickness of 80 μm was laminated on both surfaces of the polarizing film (C) as shown in Table 1. As a result, the polarizing film slightly discolored by the durability test. Moreover, the mechanical strength of the laminated film was lowered.

Claims (7)

On one surface of the polarizing film (C), a thickness of 5 to 200 [mu] m, moisture permeability 0.3~2.9g ^/ m 2 · 24h, and Ri maximum retardation value der following 4nm-plane, tricyclo [ 4.3.0.1 ^2,5 ] deca-3,7-diene, 1,4-methano-1,4,4a, 9a-tetrahydrofluorene, and tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] - dodeca-3 resin film ene polymer ing (A) is laminated on the other surface, a thickness of 20 to 200 [mu] m, moisture permeability at 50~1,500g ^/ m 2 · 24h A laminate in which a certain resin film (B) is laminated. The laminate according to claim 1, wherein the resin film (A) has a moisture permeability of 0.6 to 2.9 g / m ² · 24 h.   The laminate according to claim 1 or 2, further comprising a vinyl alcohol polymer adhesive layer between the film (A) and the polarizing film (C) and between the film (B) and the polarizing film (C). .   The laminate according to any one of claims 1 to 3, wherein the film (A) comprises an alicyclic structure-containing polymer resin as a main component.   The laminate according to any one of claims 1 to 4, wherein the film (B) contains triacetyl cellulose as a main component.   A liquid crystal display device comprising the laminate according to any one of claims 1 to 5,
  A liquid crystal display device in which the film (A) side of the laminate is provided facing the liquid crystal layer.   Thickness is 5 to 200 μm, moisture permeability is 0.3 to 2.9 g / m ² 24h and the in-plane maximum retardation value is 4 nm or less, and tricyclo [4.3.0.1 ^2,5 Deca-3,7-diene, 1,4-methano-1,4,4a, 9a-tetrahydrofluorene and tetracyclo [4.4.0.1] ^2,5 . 1 ^{7, 10} ] At least one surface of the film (A) or the polarizing film (C) made of a polymer of dodec-3-ene, and a thickness of 20 to 200 μm and a moisture permeability of 50 to 1,500 g / m. ² A solution of vinyl alcohol polymer is applied to at least one surface of the film (B) that is 24 h or one surface other than the above of the polarizing film (C), and then the film (A And the film (B) are bonded together and held at a temperature of 2 to 150 ° C. for 0.5 to 200 hours.