JP6926433B2 - Laminated film and its manufacturing method - Google Patents

Description

The present invention relates to a laminated film in which a coating layer is laminated on a polymer film, and more particularly to a laminated film having good oligomer sealing performance when exposed to a high temperature and also having excellent antistatic performance. ..

Oligomer encapsulation performance is one of the film characteristics required for films used in applications such as flat panel displays. Here, the oligomer sealing performance means the performance of suppressing the precipitation of the oligomer derived from the base film on the surface of the film. Further, from the viewpoint of improving quality and processing / inspection speed, antistatic performance is also required in addition to the above-mentioned oligomer sealing performance.

When a film that does not have sufficient oligomer encapsulation performance is heated during the manufacturing process, the oligomers contained inside the film may precipitate and aggregate on the surface, degrading the optical properties. There is.
If the antistatic property is low (or absent), static electricity may cause dust to be adsorbed on the film in the process to cause defects.

As a technique for imparting oligomer-sealing performance to a film, the Applicant applies a coating agent containing a quaternary ammonium base-containing polymer having an oligomer-sealing action to one surface of the polymer film, and then heat-treats the film. Disclosed is a technique for forming an anchor layer by further applying a coating agent containing at least one metal element selected from aluminum, titanium and zirconium, and then performing heat treatment again to form an anchor layer. (Patent Document 1).

The technique of Patent Document 1 is to form a coating layer and an anchor layer by repeating a coating step and a heat treatment step as described above.

Therefore, from the viewpoint of improving production efficiency and reducing the environmental load, a technique for realizing a film having a function equivalent to that of Patent Document 1 with a smaller number of steps has been expected.

Japanese Unexamined Patent Publication No. 2011-93173

An object of the present invention is to provide a film that meets the above expectations and is obtained without undergoing a plurality of coating steps and a plurality of heat treatment steps, and is excellent in both oligomer encapsulation performance and antistatic performance. It is to be.

As a result of diligent studies to solve the above problems, the present inventors have solved the above problems by forming a metal oxide-containing layer having a specific structure as a coating layer on at least one surface of the polymer film. He found that it could be solved and completed the following invention. The present invention provides the following [1] to [11].
[1] A metal oxide-containing layer containing a metal oxide having an amorphous structure is provided on at least one surface of the polymer film, and the metal oxide-containing layer has a single-layer structure and is heat-treated at 150 ° C. for 2 hours. A laminated film in which the amount of oligomers extracted from the surface of the film is 5.0 mg / m ^{2 or less.}
[2] The laminated film according to [1], wherein the metal oxide-containing layer further contains a metal oxide having a crystal structure.
[3] The laminated film according to [1] or [2], wherein the thickness of the metal oxide-containing layer is 0.005 μm to 5.0 μm.
[4] The laminated film according to any one of [1] to [3], wherein the haze is 20% or less.
[5] The laminated film according to any one of [1] to [4], wherein the metal oxide-containing layer contains a zinc compound.
[6] The laminated film according to any one of [1] to [5], wherein the metal oxide-containing layer contains at least one selected from the group consisting of indium, tin, aluminum, zirconium, silicon, and titanium compounds. ..
[7] The laminated film according to any one of [1] to [6], wherein the polymer film is a polyester film.
[8] The laminated film according to any one of [1] to [7], wherein the metal oxide is zinc oxide.
[9] The laminated film according to any one of [1] to [8], which has an adhesive, a mold release, or other functional layer on the metal oxide-containing layer.
[10] A coating liquid containing a compound having a metal element is applied to at least one surface of a polymer film and then dried at a temperature of 200 ° C. or lower to contain a metal oxide-containing layer containing a metal oxide having an amorphous structure. A method for producing a laminated film.
[11] Production of the laminated film according to [10], wherein the coating liquid contains at least one selected from the group consisting of at least one low molecular weight amine compound, a pyridine compound, a diketone compound, a diol compound, and an acetylene compound. Method.

According to the present invention having the above structure, it is possible to realize a film having both excellent oligomer sealing performance and antistatic performance without going through a plurality of coating steps and a plurality of heat treatment steps.

It is the schematic of the laminated film.

Hereinafter, the laminated film according to the embodiment of the present invention will be described in detail.
As shown in FIG. 1, the laminated film of the present invention includes a polymer film 1 and a metal oxide-containing layer 2.

(Polymer film)
The polymer film may have a single-layer structure consisting of only the base film, or a multilayer structure in which a layer is layered on the base film.

Examples of the material of the base film include polyester, polystyrene, polycarbonate, polyether sulfone, polyamide, and polyimide having excellent heat resistance. Among them, the polyester film is particularly preferable because it is excellent in physical properties such as cost, heat resistance, flatness, optical properties, and strength.
Polyester is a dicarboxylic acid such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 4,4'-diphenyldicarboxylic acid, 1,4-cyclohexyldicarboxylic acid or an ester thereof and ethylene. It is a polyester produced by melt polycondensation with glycols such as glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol and 1,4-cyclohexanedimethanol. The polyester composed of these acid components and glycol components can be produced by using any of the usual methods.

For example, the transesterification reaction between the lower alkyl ester of the aromatic dicarboxylic acid and the glycol, or the direct esterification of the aromatic dicarboxylic acid and the glycol is carried out to substantially bisglycol the aromatic dicarboxylic acid. A method is adopted in which an ester or a low polymer thereof is formed, and then this is heated under reduced pressure to carry out polycondensation. Aliphatic dicarboxylic acids may be copolymerized according to the purpose.

Typical examples of the polyester include polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and the like, but in addition, polyester obtained by copolymerizing the above acid component and glycol component. It may contain other components and additives as needed.
When the polymer film is a polyester film having a multilayer structure, the surface layer and the inner layer, or both surface layers and each layer can be made of different polyesters depending on the purpose.

When the additive is added to the polymer film, it can be added to the single-layer film or only a part of the layers of the multilayer film. For example, by forming a polymer film into a three-layer structure and adding particles to one or both outer layers without adding particles to the inner layer, both slipperiness and transparency can be achieved.

As the base film constituting the polymer film, it is preferable to use a polyester film having a low oligomer content.
The polyester having a low oligomer content refers to a polyester having a cyclic trimer content of 0.7% by weight or less. Particularly preferably, the amount of the cyclic trimer is 0.5% by weight or less.
When the cyclic trimer is 0.7% by weight or less, the phenomenon that the oligomer is deposited on the surface of the polymer film when the polyester film is heated at a high temperature can be effectively suppressed.
It should be noted that simply reducing the oligomer content does not mean that the amount of precipitation decreases accordingly. For example, when heating is performed with an adhesive layer or the like provided on the surface of the polymer film, the amount of precipitation is significantly reduced at a boundary of about 0.5% by weight.

When the polymer film has a single-layer structure, the polymer film is preferably composed of 80% by weight or more of polyester having a content of cyclic trimers of 0.5% by weight or less.
When the polymer film has a multilayer structure, it is preferably composed of 80% by weight or more of polyester having a content of cyclic trimers of 0.5% by weight or less in the base film in contact with the undercoat layer.
In the present specification, the undercoat layer is a layer formed on the surface of a base film in a polymer film having a multilayer structure, and further improves adhesion with a layer laminated on the upper layer and prevents static electricity. It means a layer having a function of imparting properties and preventing low molecular weight components from seeping out from the polymer film. The undercoat layer is obtained by applying a coating liquid for forming an undercoat layer having a ratio of a cross-linking agent to all non-volatile components of 70% by weight or more to a base film and drying it. Other components may be contained in the coating liquid for forming the undercoat layer.

When the polymer film has a multilayer structure and the surface layer of the film is polyester having a low oligomer content, the thickness of the surface layer is preferably 4 μm or more, more preferably 5 μm or more. The thicker the surface layer, the more the precipitation of oligomers is suppressed. On the other hand, when the thickness of the surface layer is thinner than the above range, a sufficient effect of suppressing the precipitation of oligomers may not be obtained.

The polymer film can contain particles for the purpose of ensuring the runnability of the film and preventing scratches. Examples of such particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, calcium phosphate, kaolin, talc, aluminum oxide, titanium oxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and molybdenum sulfide. , Crosslinked polymer particles, organic particles such as calcium oxalate, and precipitated particles during the polyester production process can be used.

The particle size and content of the particles to be used are selected according to the intended use and purpose of the film, but the average particle size (d50) is usually 0.01 μm to 3 μm, preferably 0.02 μm to 2.5 μm, more preferably 0.02 μm to 2.5 μm. Is in the range of 0.03 μm to 2 μm. By setting the average particle size to 0.01 μm or more, it is possible to avoid the problem that the surface roughness is too small to obtain sufficient slipperiness. By setting the average particle size to 3.0 μm or less, it is possible to avoid the phenomenon that the surface roughness of the film becomes too rough and the particles easily fall off from the film surface.

The particle content is usually in the range of 0.0003 to 1.0% by weight, preferably 0.0005 to 0.5% by weight, based on the polyester layer containing the particles. By setting the particle content to 0.0003% by weight or more, sufficient slipperiness can be imparted to the film. By setting the particle content to 1.0% by weight or less, sufficient transparency can be imparted to the film.
If it is desired to particularly improve the transparency and smoothness of the film, the film may be configured to contain substantially no particles. Further, various stabilizers, lubricants, antistatic agents and the like can be added to the film as appropriate.

As a film-forming method for a polymer film, a generally known film-forming method can be adopted, and there is no particular limitation. For example, the sheet obtained by melt extrusion is first stretched 2 to 6 times at 70 to 145 ° C. by a roll stretching method to obtain a uniaxially stretched polyester film, and then in a tenter, perpendicular to the previous stretching direction. A film is obtained by stretching 2 to 6 times in the direction at 80 to 160 ° C. and further performing heat treatment at 150 to 250 ° C. for 1 to 600 seconds. Further, at this time, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the lateral direction in the heat treatment zone and / or the cooling zone at the heat treatment outlet is preferable.

The film thickness of the polymer film is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more, from the viewpoint of ease of handling during processing. Further, 500 μm or less is preferable, 300 μm or less is preferable, and 250 μm or less is more preferable.

As for the heat shrinkage rate of the polymer film, the shrinkage rate when heated at 180 ° C. for 5 minutes is preferably 2.0% or less, more preferably 1.5% or less in the MD (length) direction. , 1.0% or less is more preferable. The shrinkage rate when heated at 180 ° C. for 5 minutes is preferably 1.0% or less, more preferably 0.7% or less, and 0.5% or less in the TD (width) direction. Is even more preferable.

The undercoat layer may be formed by in-line coating. Although the number of processing steps is increased by forming the undercoat layer, it is possible to produce a laminated film having higher performance. The undercoat layer is preferably obtained by applying a coating liquid in which the ratio of the cross-linking agent to all non-volatile components is 70% by weight or more and drying. The coating liquid may contain other components.

The cross-linking agent described here is a cross-linking resin that reacts with heat in particular, and examples thereof include amino resin-based, isocyanate-based, oxazoline-based, and epoxy-based. Also included are polymer-type cross-linking reactive compounds in which other polymer skeletons have reactive groups.
In particular, by using an oxazoline-based cross-linking agent, it is possible to achieve both suppression of oligomer precipitation and an undercoat layer having a good appearance.

Further, it is particularly preferable to use two or more kinds of cross-linking agents in combination because the effect of suppressing oligomers precipitated from the polyester film during heating is enhanced. This is probably due to the presence of cross-linking agents with different reaction rates when the undercoat layer coating solution is applied and dried to form the undercoat layer, which more effectively fills the voids in the coating layer and is an oligomer. It is presumed that this is because it is a layer that suppresses the precipitation of.

As a result of examining various combinations, the effect obtained is particularly high when the oxazoline type and the epoxy type are used in combination, or when the amino resin type, the oxazoline type and the epoxy type are used in combination.

As the oxazoline-based cross-linking agent, a polymer containing an oxazoline group in the molecule is preferable, and it can be prepared by polymerization of an addition-polymerizable oxazoline group-containing monomer alone or with another monomer. Additive polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-Isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like can be mentioned, and one or a mixture of two or more thereof can be used. Of these, 2-isopropenyl-2-oxazoline is industrially readily available and suitable, but the other monomer may be a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer. The oxazoline-based cross-linking agent in the present invention has an oxazoline group content in the range of 0.5 to 10 mmol / g, preferably 3 to 9 mmol / g, and more preferably 5 to 8 mmol / g. In particular, when two or more kinds of cross-linking agents are used in combination, the effect obtained by selecting an oxazoline-based cross-linking agent within the above range is high.

An epoxy-based cross-linking agent is a compound having an epoxy group in the molecule. For example, a condensate of epichlorohydrin with a hydroxyl group or amino group such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, or bisphenol A. There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds and the like. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, Polytetramethylene glycol diglycidyl ether, Monoepoxy compounds include, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, glycidyl amine compounds N, N, N', N Examples thereof include'-tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like.

Among the amino resin-based cross-linking agents, those in which the amino group of the melamine resin is methylolated and a part of the methylol group is methylated are water-soluble, easy to handle, highly reactive, and have an undercoat layer and a group. A polymer film having excellent adhesion to a material film and durability of a coating layer can be obtained.

When such a cross-linking component is contained, a component for promoting cross-linking, for example, a cross-linking catalyst can be used in combination at the same time.

The coating liquid for providing the undercoat layer may contain components other than those described above, if necessary. For example, surfactants, other binders, particles, defoamers, coatability improvers, thickeners, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like. These additives may be used alone, or two or more thereof may be used in combination if necessary.

The thickness of the undercoat layer is usually in the range of 0.003 μm to 1 μm as the film thickness on the biaxially stretched polyester film. It is preferably in the range of 0.005 μm to 0.5 μm, more preferably 0.01 μm to 0.2 μm. By setting the thickness to 0.003 μm or more, the amount of oligomers precipitated from the film can be sufficiently reduced. By setting the thickness to 1 μm or less, problems such as deterioration of the appearance of the undercoat layer and easy blocking can be reliably avoided.

To determine the thickness of the undercoat layer, the coating film is dyed with a heavy metal such as a ruthenium compound or an osmium compound, the cross section of the coating film is adjusted by the ultrathin section method, and then the coating film cross section is coated with a transmission electron microscope. It can be confirmed by observing multiple layers and averaging the measured values.

As a method of applying the coating liquid for the undercoat layer to the base film, for example, a coating technique as shown in "Coating Method" by Yuji Harasaki, Maki Shoten, published in 1979 can be used. Specifically, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roll coater, transfer coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, calendar coater. , Extrusion coater and the like.

In addition, in order to improve the coatability and adhesiveness of the coating liquid for the undercoat layer to the base film, the base film may be subjected to chemical treatment, corona discharge treatment, plasma treatment or the like before coating.

(Metal oxide-containing layer)
A conductive metal oxide-containing layer is provided on at least one surface of the polymer film. This metal oxide-containing layer contains a metal oxide having an amorphous structure.

The method for forming the metal oxide-containing layer is not particularly limited, but for example, after applying a coating solution containing a compound having a metal element (hereinafter referred to as a precursor solution) to at least one surface of the polymer film, the temperature is 200 ° C. or lower. It can be formed by drying at the temperature of.

The metal element is preferably at least one metal element selected from Zn, Mo, In, Sb, Sn, Ga, Ge, Cu, Ag, Ti, Cd, Te, Se, W, and Ce. Only one type may be used, or two or more types may be mixed.
In particular, Zn has good reactivity, and it is easy to obtain high conductivity and oligomer-sealing property even in low-temperature processing. Further, by mixing two or more kinds of metal elements, it is expected to have an effect of increasing the conductivity of the metal oxide layer, suppressing excessive crystallization, and suppressing a decrease in conductivity and oligomer encapsulation.

Specific examples of the compound having Zn include zinc diacetate, zinc dinitrate, zinc diacetylacetone, diethyl zinc, zinc diisopropoxide, zinc hexafluoroacetylacetonate, zinc dihydroxyde, zinc dichloride, and the like. NS. Moreover, you may use the hydrate of the said compound.

At least one metal selected from In, Sn, Al, Zr, Si, and Ti in the above-mentioned precursor solution in order to improve the surface intrinsic resistance value and / or oligomer encapsulation property of the metal oxide-containing layer. Compounds having elements may be added. Only one of these may be used, or two or more may be mixed.
The surface intrinsic resistance is ^{preferably 1 × 10 13} Ω or less, ^{more preferably 1 × 10 12} Ω or less, and further preferably 1 × 10 ¹⁰ Ω or less. By setting the surface specific resistance to 1 × 10 ¹³ Ω or less, it is possible to avoid deterioration of transparency and visibility due to deterioration of the property of preventing foreign substances adhering to dust and the like. Further, by setting the surface specific resistance to 1 × 10 ¹³ Ω or less, it is possible to avoid a decrease in handleability, and more elaborate post-processing can be sufficiently performed.

Specific examples of the compound having In include indium acetate, indium tertiary butoxide, indium acetylacetone, indium trichloride, indium trihydroxyde and the like.

Specific examples of the compound having Sn include dibutin tinbis (acetylacetoneate), tinter-shaributoxide, tin chloride, tin hydroxide and the like.

Specific examples of the compound having Al include aluminum tris (acetylacetonate), aluminum monoacetylacetonate bis (ethylacetacetate), aluminum-di-n-butoxide-monoethylacetate, and aluminum-di-iso. -Propoxide-monomethylacetacetate, aluminum trichloride, aluminum trihydroxyde and the like are exemplified.

Specific examples of the compound having Zr include zirconium acetate, zirconium normal propyrate, zirconium normal butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium chloride and the like. ..

Specific examples of the compound having Si include vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltri. Methoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxipropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 5-hexenyltrimethoxysilane, p-styryltrimethoxy Examples thereof include silane, trifluoropropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and γ-glycidoxypropylmethyldiisopropenoxysilane.

Specific examples of the compound having Ti include, for example, titanium diisopropoxide bisacetate, titanium butoxide, titanium isopropoxide, titanium methoxyde, titanium oxide acetylacetonate, titanium propoxide, titanium tertiary butoxide, titanium tetrahydrofur. Frill oxide and the like are exemplified.

Amine compounds and pyridine compounds are added to the precursor solution for the purpose of increasing the solubility and dispersibility of the precursor solution and the solubility and dispersibility of the metal hydroxide formed by the hydrolysis of the compound in the precursor solution. , Diketone compounds, diol compounds, and acetylene compounds are preferably added.
The compound added here is preferably a small molecule that can be volatilized when the precursor solution is dried so as not to inhibit the formation of the metal oxide-containing layer. The boiling point of the compound to be added is preferably 200 ° C. or lower, more preferably 180 ° C. or lower, further preferably 170 ° C. or lower, and even more preferably 150 ° C. or lower. Specific examples of amine compounds, pyridine compounds, diketone compounds, diol compounds, and acetylene compounds include monoethanolamine, ethylenediamine, triethylamine, diisopropylethylamine, 2,6-lutidine, glycine, acetylacetone, ethylene glycol, and 2-proptin-1-. Examples thereof include all, 2-methyl-3-butin-2-ol, trimethyl (3-methyl-1-butin-3-oxy) silane, 1-ethynyl-1-cyclohexanol and the like. Only one type may be used, or two or more types may be mixed.
Mixing a low nucleophilic amine compound (such as diisopropylethylamine) and / or a pyridine compound (such as 2,6-lutidine) with a diol compound and / or an acetylene compound is a reaction in the next step, such as forming a silicone release layer. This is particularly preferable because it is less likely to inhibit the above and the solubility of the precursor solution can be increased.

At this time, it is preferable to use a catalyst in combination for the purpose of promoting the hydrolysis / condensation reaction. Specific examples of the catalyst include organic acids such as acetic acid, butyric acid, maleic acid and citric acid, inorganic acids such as hydrochloric acid, nitrate, phosphoric acid and sulfuric acid, basic compounds such as triethylamine, tetrabutyl titanate and dibutyltin dilaurate. Organic metal salts such as dibutyltin diacetate, dibutyltin dioctate, dibutyltin diolate, diphenyltin diacetate, dibutyltin oxide, dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dibutyltin benzylmalate, etc., KF, NH ₄ Examples thereof include a fluorine element-containing compound such as F. The catalyst may be used alone or in combination of two or more. Among them, organometallic salts are particularly preferable in terms of improving the durability of the coating film, and more preferably a tin catalyst is used in that the catalytic activity is sustainable for a long period of time. In addition to the tin catalyst, an alkoxide containing a metal such as titanium, zirconium, or lanthanoid, a chelate, an acylate, or the like may be used as the catalyst.

Further, inorganic particles may be contained for the purpose of improving the adhesiveness and slipperiness of the metal oxide-containing layer, and specific examples thereof include silica, alumina, kaolin, calcium carbonate, titanium oxide, and barium salt.
Further, for the purpose of improving the surface specific resistance value, a conductive metal, metal oxide particles, a filler, or the like may be contained. Impurities such as a boron compound and a phosphorus compound may be added as the dopant.

Further, if necessary, a defoaming agent, a coatability improving agent, a thickener, an organic lubricant, an ultraviolet absorber, a dye and the like may be contained.

In addition, an organic solvent can be used for the purpose of improving dispersibility, film forming property, etc., as long as the gist of the present invention is not exceeded. Only one kind of organic solvent may be used, and two or more kinds may be used as appropriate.

The amount of the precursor solution applied is adjusted so that the thickness after drying is in the range of 0.005 μm to 5.0 μm, preferably 0.010 μm to 2.0 μm, and more preferably 0.20 μm to 1.0 μm. .. By setting the coating amount to 0.005 μm or more, the uniformity of the coating thickness can be sufficiently ensured, and the amount of oligomers precipitated from the surface of the coating layer after the heat treatment can be surely reduced. By setting the coating amount to 5.0 μm or less, problems such as cracks can be reliably avoided, and the effect of cost reduction can be obtained.

The precursor solution can be applied in the same manner as the method of applying the undercoat layer coating solution. An in-line coating may be used, or a so-called offline coating, which is applied once on a manufactured film, may be used.

The drying temperature at which the precursor solution is applied and then dried at a temperature of 200 ° C. or lower to form a metal oxide-containing layer is preferably 60 to 200 ° C., more preferably 80 ° C. to 190 ° C., still more preferably 100 ° C. It is ~ 180 ° C., particularly preferably 120 ° C. to 160 ° C.
The drying time is preferably 3 seconds to 600 seconds, more preferably 5 seconds to 300 seconds, still more preferably 10 seconds to 180 seconds, and particularly preferably 15 seconds to 120 seconds.
If necessary, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination.
If the thermal energy for forming the metal oxide-containing layer is insufficient, the reaction of the precursor in the precursor solution does not proceed sufficiently, the surface intrinsic resistance value increases, and the amount of oligomer precipitation increases. Not preferred.
On the other hand, when the thermal energy for forming the metal oxide-containing layer becomes excessive, the crystallinity of the metal oxide-containing layer becomes too high (that is, the ratio of the metal oxide in the crystal structure in the metal oxide-containing layer becomes too high. (Excess), cracks are likely to occur in the film, which increases the surface intrinsic resistance value and increases the amount of oligomers deposited, which is not preferable.
In the present invention, by adjusting the amount of heat applied so that the metal oxide-containing layer formed on the polymer film contains the metal oxide having an amorphous structure, the problem caused by the excess or deficiency of energy as described above ( The problem that the surface specific resistance value becomes high and the amount of oligomer precipitation increases) has been solved.
The degree of crystallization of the metal oxide-containing layer (that is, the ratio of the metal oxide in the crystal structure in the metal oxide-containing layer) is selected in consideration of the balance between conductivity and oligomer encapsulation.
The fact that the metal oxide-containing layer contains a metal oxide having an amorphous structure can be evaluated from the broadening of the X-ray diffraction peak and the surface shape observation by AFM.
The degree of crystallization is evaluated by comparing an uncrystallized sample in which a metal oxide-containing layer is formed on a quartz substrate or the like and the solvent is dried, and a sample in which crystallization is completed by high-temperature, long-term annealing. It is possible to do.

(Release layer)
As shown in FIG. 1, the release layer 3 may be provided on the metal oxide-containing layer 2.
As the release layer, a type containing a curable silicone resin as a main component may be used, or a modified silicone type or the like obtained by graft polymerization with an organic resin such as a urethane resin, an epoxy resin or an alkyd resin may be used.

As the type of the curable silicone resin, any curing reaction type such as addition type, condensation type, ultraviolet curable type, electron beam curable type, and solvent-free type can be used.

Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2422, X-62-2461, manufactured by Shin-Etsu Chemical Co., Ltd. DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210 manufactured by Dow Corning Asia Co., Ltd., YSR-3022, TPR-6700, TPR-6720, TPR- manufactured by Toshiba Silicone Co., Ltd. 6721, SD7220, SD7226, SD7229, etc. manufactured by Toray Dow Corning Co., Ltd. can be mentioned. Further, a peeling control agent may be used in combination to adjust the peelability of the release layer.

As a method of providing the release layer, a conventionally known coating method such as reverse roll coating, gravure coating, bar coating, and doctor blade coating can be used.

In addition to the release layer, other functional layers such as a hard coat layer, an adhesive layer, an antireflection film, a barrier film, and a self-assembled monolayer may be provided.

The amount of the release layer applied is usually in the range of ^{0.01 to 1 g / m 2 as a dry film after the release layer is formed.} The coating amount of the release layer can be calculated from the weight concentration and coating area of the paint and the amount of the paint used.
By setting the coating amount to 0.01 g / m ² or more, uniform releasability can be ensured. By setting the coating amount to 1 g / m ² or less, problems such as blocking can be avoided.

The thickness of the release layer can be confirmed from the cross section with a transmission electron microscope as described above, and the coating amount can be obtained by dividing by the specific gravity. Generally, the specific gravity of curable silicone is often about 0.9 to 1.2. The coating amount of the release layer having a thickness of 0.1 μm is 0.1 g / m ² when the specific gravity is 1.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(1) Measurement of surface specific resistance value:
Using a surface resistance tester (MC-HT800) manufactured by Mitsubishi Chemical Analytech, two measurements were performed by the following method, and the average value was adopted.
After adjusting the humidity of the sample for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH, the surface specific resistance value of the film surface after 1 minute is measured at an applied voltage of 500 V or 250 V. It can be said that the lower the surface specific resistance value, the better the antistatic property.

(2) Measurement of oligomers extracted from the surface of the laminated film:
The coating liquid for forming the metal oxide-containing layer is applied, and the dried polymer film is heated in air at 150 ° C. for 2 hours. After that, the heat-treated film is brought into close contact with the inner surface of a box having an open top of 10 cm in length and width and 3 cm in height to form a box shape. At this time, the coating layer should be inside the box. Next, 10 ml of DMF (dimethylformamide) is placed in the box prepared by the above method and left for 3 minutes, and then DMF is collected. The recovered DMF was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-2010C HT) to determine the amount of oligomers in DMF, and this value was divided by the area of the film in contact with DMF to obtain the amount of oligomers on the film surface (manufactured by Shimadzu Corporation: LC-2010CHT). It shall be mg / m ^2).

The amount of oligomers in DMF was determined from the peak area ratio of the standard sample peak area and the measured sample peak area (absolute calibration curve method). A standard sample was prepared by accurately weighing a pre-prepared oligomer (cyclic trimer) and dissolving it in accurately weighed DMF. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml. The conditions of the liquid chromatograph were as follows.

Moving layer A: Acetonitrile Moving layer B: 2% aqueous acetic acid solution Column: "MCI GEL ODS 1HU" manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow velocity: 1 ml / min Detection wavelength: 254 nm

[Example 1]
A solution consisting of 1.0 g of zinc acetate dihydrate, 0.28 g of ethanolamine, and 10 g of 2-methoxyethanol was applied onto a 38 μm-thick biaxially stretched PET film using a bar coater (No. 4 bar). After that, it was dried in an oven at 150 ° C. for 30 seconds to prepare a PET film with a zinc oxide layer.
The obtained laminated film has high transparency, and it is considered that a zinc oxide-containing layer containing zinc oxide having a uniform amorphous structure was formed. When the film thickness of the zinc oxide layer was measured by a cross-sectional SEM, it was 90 nm on average at three points.

[Example 2]
A solution consisting of 1.0 g of zinc acetate dihydrate, 0.1 g of a silane coupling agent (3-glycidoxypropylmethyldimethoxysilane), 0.28 g of ethanolamine, and 10 g of 2-methoxyethanol was prepared by using a bar coater (No. After applying on a biaxially stretched PET film having a thickness of 38 μm using 4 bars), the mixture was dried in an oven at 150 ° C. for 30 seconds to prepare a PET film with a zinc oxide layer.

[Example 3]
A solution consisting of 1.0 g of zinc acetate dihydrate, 0.1 g of a silane coupling agent (3-glycidoxypropylmethyldimethoxysilane), 0.003 g of dibutyltin acetate, 0.28 g of ethanolamine, and 10 g of 2-methoxyethanol. , A bar coater (No. 4 bar) was applied on a biaxially stretched PET film having a thickness of 38 μm, and then dried in an oven at 150 ° C. for 30 seconds to prepare a PET film with a zinc oxide layer.

[Example 4]
Zinc acetate dihydrate 1.0 g, silane coupling agent (3-glycidoxypropylmethyldimethoxysilane) 0.1 g, dibutyltin acetate 0.003 g, aluminum trisacetylacetonate 0.04 g, ethanolamine 0.28 g, A solution consisting of 10 g of 2-methoxyethanol was applied on a biaxially stretched PET film having a thickness of 38 μm using a bar coater (No. 4 bar), dried in an oven at 150 ° C. for 30 seconds, and with a zinc oxide layer. PET film was prepared.
When the film thickness of the zinc oxide layer was measured by a cross-sectional SEM, it was 125 nm on average at three points.

[Example 5]
A PET film with a zinc oxide layer was prepared in the same manner as in Example 1 except that the drying temperature was set to 160 ° C.

[Example 6]
A PET film with a zinc oxide layer was prepared in the same manner as in Example 2 except that the drying temperature was set to 160 ° C.

[Example 7]
A PET film with a zinc oxide layer was prepared in the same manner as in Example 3 except that the drying temperature was set to 160 ° C.

[Example 8]
A PET film with a zinc oxide layer was prepared in the same manner as in Example 4 except that the drying temperature was set to 160 ° C.

[Comparative Example 1]
A PET film not coated with a zinc oxide layer was used as a comparative example for evaluating the oligomer encapsulation.

[Example 9]
A PET film with a zinc oxide layer was prepared in the same manner as in Example 1 except that the drying temperature was 130 ° C. and the drying time was 3 minutes.

[Example 10]
A solution consisting of 0.9 g of zinc acetate dihydrate, 0.1 g of aluminum chloride as a dopant, 0.28 g of ethanolamine, and 10 g of 2-methoxyethanol was prepared using a bar coater (No. 4 bar) to a thickness of 38 μm. After coating on a shaft-stretched PET film, it was annealed in an oven at 130 ° C. for 3 minutes.

Tables 1 and 2 summarize the evaluation results of the obtained PET film with zinc oxide layer (Table 1: Zinc oxide film surface specific resistance value, surface oligomer amount, haze value, Table 2: Zinc oxide film surface specific resistance value. Value, haze value).
The haze is preferably 20% or less. It is more preferably 10% or less, further preferably 5% or less, and particularly preferably 3% or less. If the haze becomes excessively large, it may be difficult to use in appearance in optical applications, but if it is 20% or less, a good appearance can be obtained. In the present specification, haze means a value measured by an integrating sphere type turbidity meter NDH-2000 manufactured by Nippon Denshoku Kogyo Co., Ltd. according to JIS-K7136.
When the surface specific resistance value of the prepared PET film with a zinc oxide layer was measured, the zinc oxide layer formed by coating showed conductivity. In addition, the amount of oligomers on the surface is kept low even after heating at 150 ° C. for 2 hours, and good antistatic properties and oligomer sealing properties can be obtained with a single coat and at a low drying temperature of 200 ° C. or lower. It turned out.

* 測定範囲外（＞10¹⁴Ω／□）

* Out of measurement range (> 10 ¹⁴ Ω / □)

The characteristics of the laminated film change depending on the drying conditions, and in the comparison between Example 1 heated at 150 ° C. for 30 seconds and Example 5 heated at 160 ° C. for 30 seconds, the surface specific resistance value was heated at 150 ° C. for 30 seconds. 1 was good. In addition, better results were obtained in Example 1 for the haze of the film.

The mechanism of the large difference in film properties due to different drying temperatures is not completely clear, but probably the film quality (crystallinity) of the metal oxide-containing layer (zinc oxide layer in the above example). It is considered that the difference in the coefficient of thermal expansion between the polymer film and the metal oxide-containing layer has an effect.
Normally, it is expected that the surface specific resistance value will be lowered by increasing the crystallinity of the metal oxide-containing layer and increasing the conductivity of the film by heating at a high temperature. However, it is considered that a highly crystalline film is mechanically weak against expansion and contraction, and if the temperature is too high, extremely small cracks occur in the metal oxide-containing layer, which increases the resistance of the surface intrinsic resistance value. It is considered that problems such as an increase in haze and a decrease in oligomer sealing performance will occur.
In the present invention, the above problem is solved by assuming that the metal oxide-containing layer contains an amorphous structure by adjusting the drying temperature, the drying time, and the precursor solution.

By adding a silane coupling agent, a tin catalyst, and an aluminum compound to the coating liquid, it is possible to change and improve the characteristics of the laminated film.
When the silane coupling agent (Example 2) was added, the surface specific resistance value increased slightly, but the oligomer encapsulation property was improved. On the other hand, the haze has risen significantly.
By further adding the tin catalyst (Example 3), the surface specific resistance value was slightly increased, but the oligomer encapsulation property was further improved. Haze didn't change much.
Further, by adding the aluminum compound (Example 4), the surface specific resistance value was increased, but the haze increased by the addition of the silane coupling agent was greatly reduced.

When the coating layer was dried at 160 ° C. for 30 seconds (Examples 5 to 8), the surface specific resistance value was lower with the additive. It is considered that the heat resistance is improved.

When the coating layer was dried at 130 ° C. for 3 minutes (Example 9), a lower surface intrinsic resistance was obtained. However, the haze increased, probably due to the lack of heat during drying.
On the other hand, in Example 10 to which the aluminum compound (aluminum chloride) was added, the haze increase was suppressed. In addition, the lowest surface intrinsic resistance value was obtained. The mechanism of lowering the resistance is not clear, but it is expected to be the effect of doping the metal oxide-containing layer with aluminum and / or chlorine.

1 Polymer film 2 Metal oxide-containing layer 3 Release layer

Claims (8)

A coating liquid containing a compound having a metal element is applied to at least one surface of the polymer film and then dried at a temperature of 200 ° C. or lower to form a metal oxide-containing layer containing a metal oxide having an amorphous structure. , A method for manufacturing laminated films,
The metal oxide-containing layer contains a zinc compound and a silicon compound, and contains
The compound having a metal element contains a compound containing zinc and a compound containing silicon, and contains
Compound Jin lottery acetate containing the zinc, Jin lottery nitrate, Jin lottery acetylacetonate, Jin lottery isopropoxide, zinc hexafluoroacetylacetonate, zinc dihydroxide, and Jinkujiku Lola Id and the hydrates of these compounds, At least one selected from
The metal oxide-containing layer has a single-layer structure.
The amount of oligomer extracted from the surface of the laminated film heat-treated at 150 ° C. for 2 hours is 5.0 mg / m ² or less.
A method for producing a laminated film, wherein the haze of the laminated film is 20% or less. The method for producing a laminated film according to claim 1, wherein the thickness of the metal oxide-containing layer is 0.005 μm to 5 μm. The method for producing a laminated film according to claim 1 or 2, wherein the metal oxide-containing layer contains at least one selected from a tin compound and an aluminum compound. The method for producing a laminated film according to any one of claims 1 to 3, wherein the metal oxide-containing layer contains at least one selected from an indium compound, a zirconium compound, and a titanium compound. The method for producing a laminated film according to any one of claims 1 to 4, wherein the polymer film is a polyester film. The method for producing a laminated film according to any one of claims 1 to 5, wherein the metal oxide is zinc oxide. The method for producing a laminated film according to any one of claims 1 to 6, which has a functional layer on the metal oxide-containing layer. The method for producing a laminated film according to any one of claims 1 to 7, wherein the coating liquid contains at least one kind of low molecular weight amine compound, a pyridine compound, a diketone compound, a diol compound, and an acetylene compound.

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