WO2012144416A1

WO2012144416A1 - Coated film

Info

Publication number: WO2012144416A1
Application number: PCT/JP2012/060030
Authority: WO
Inventors: 児玉藍子; 神田俊宏; 藤田真人; 川崎陽一
Original assignee: 三菱樹脂株式会社
Priority date: 2011-04-18
Filing date: 2012-04-12
Publication date: 2012-10-26

Abstract

Provided is a coated film which comprises a coating layer having excellent durability with respect to solvents and exhibits excellent adhesiveness even after being treated with a solvent. A coated film that comprises a coating layer, which is formed from a coating liquid that contains a polyurethane, on the surface of a polyester film. The polyurethane contains, as a constituent, a polycarbonate polyol that is obtained by copolymerizing two kinds of carbonate diols having different main chain structures.

Description

Coating film

The present invention relates to a coating film having a coating layer that is excellent in durability against a solvent, in particular, adhesion after solvent treatment.

Biaxially stretched polyester film excels in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, gas barrier properties, chemical resistance, etc., packaging materials, plate making materials, display materials, transfer materials, window stickers In addition to materials, it is widely used for antireflection films used for membrane switches and flat displays, optical films such as diffusion sheets and prism sheets, and transparent touch panels. However, when other materials are applied and laminated on the polyester film in such applications, there is a drawback that the adhesiveness is poor depending on the materials used.

As one of the methods for improving the adhesiveness of the biaxially stretched polyester film, a method of applying various resins to the surface of the polyester film and providing a coating layer having easy adhesion performance is known. A technique for improving the adhesiveness by providing is also known as one of them. As the polyurethane resin, a water-soluble or water-dispersible urethane resin having an anionic group is recommended. As a method for producing such a urethane resin, a compound having an anionic group together with a polyol compound, a polyisocyanate compound, a chain extender and the like. Although the method using this is disclosed, as the polyol compound and polyisocyanate compound, general-purpose compounds are exemplified (Patent Document 1).

As the resin provided in the coating layer, a water-based material is attracting attention while a reduction in volatile organic substance concentration (VOC) is targeted as an approach to environmental problems in recent years. The coating film performance tends to be inferior to that of polyurethane, and the durability of the coating layer with respect to the solvent also tends to be inferior.

Japanese Patent Laid-Open No. 11-286092

The present invention has been made in view of the above circumstances, and a problem to be solved is to provide a coated film that is excellent in durability against a solvent and exhibits excellent adhesion even after solvent treatment.

As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be easily solved by adopting a specific configuration, and the present invention has been completed.

That is, the gist of the present invention is a coating film having a coating layer formed from a coating liquid containing polyurethane on the surface of a polyester film, wherein the polyurethane is a copolymer of two types of carbonate diols having different main chain structures. The coated film is characterized in that it is a polyurethane having a polycarbonate polyol as a constituent component.

According to the present invention, it is possible to provide a coated film having excellent durability against a solvent and exhibiting excellent adhesiveness even after solvent treatment, and the industrial value of the present invention is high.

The base film of the coated film of the present invention is made of polyester. Such polyesters include dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 4,4′-diphenyldicarboxylic acid, 1,4-cyclohexyldicarboxylic acid or esters thereof. It is a polyester produced by melt polycondensation with glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol. Polyesters composed of these acid components and glycol components can be produced by arbitrarily using a commonly used method. For example, a transesterification reaction between a lower alkyl ester of an aromatic dicarboxylic acid and a glycol, or a direct esterification of an aromatic dicarboxylic acid and a glycol, to form a substantially bisglycol of an aromatic dicarboxylic acid A method is employed in which an ester or a low polymer thereof is formed and then polycondensed by heating under reduced pressure. Depending on the purpose, an aliphatic dicarboxylic acid may be copolymerized.

Typical examples of the polyester include polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and the like. In addition, polyester obtained by copolymerizing the above acid component and glycol component. And may contain other components and additives as necessary.

The polyester film can contain particles for the purpose of ensuring the film runnability 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. Further, organic particles such as crosslinked polymer particles and calcium oxalate, and precipitated particles during the polyester production process can be used.

The particle size and content of the particles used are selected according to the application and purpose of the film, but the average particle size is usually in the range of 0.01 to 5.0 μm. If the average particle size exceeds 5.0 μm, the surface roughness of the film may become too rough, or the particles may easily fall off from the film surface. When the average particle size is less than 0.01 μm, the surface roughness is too small and sufficient slipperiness may not be obtained.

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. When the particle content is less than 0.0003% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 1.0% by weight, the transparency of the film is poor. It may be enough. In addition, when it is particularly desired to ensure transparency, smoothness, etc. of the film, it can also be configured so as not to substantially contain particles. In addition, various stabilizers, lubricants, antistatic agents and the like can be appropriately added to the film.

As the film forming method, a generally known film forming method can be adopted, and there is no particular limitation. For example, a 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 perpendicular to the previous stretching direction in a tenter. A film can be 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 transverse direction in the heat treatment zone and / or the cooling zone at the heat treatment outlet is preferable.

The base polyester film has a single layer or multilayer structure. In the case of a multilayer structure, the surface layer and the inner layer, or both the surface layer and each layer can be made of different polyesters depending on the purpose.

The coated film of the present invention has a coated layer on at least one side, but even if a similar or other coated layer or functional layer is provided on the opposite side of the film, it is naturally included in the concept of the present invention.

The coating layer in the present invention is obtained by coating a coating composition on a polyester film. Various methods can be applied to the coating, but a so-called in-line coating in which a coating layer is provided during film formation, particularly a coating stretching method in which stretching is performed after coating is preferably used.

In-line coating is a method of coating within the process of manufacturing a polyester film. Specifically, it is a method of coating at any stage from melt extrusion of polyester to biaxial stretching and then heat setting and winding. is there. Normally, it is coated on either a substantially amorphous unstretched sheet obtained by melting and quenching, then a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction), or a biaxially stretched film before heat setting. To do. In particular, as a coating stretching method, a method of stretching in the transverse direction after coating on a uniaxially stretched film is excellent. According to such a method, since film formation and coating layer coating can be performed simultaneously, there is an advantage in manufacturing cost, and since stretching is performed after coating, a uniform coating with a thin film is achieved, so that adhesion performance is stabilized. .

Also, the polyester film before biaxial stretching is first coated with an easy-adhesive resin layer, and then the film and the coating layer are stretched simultaneously, whereby the base film and the coating layer are firmly adhered. In addition, biaxial stretching of the polyester film is achieved by stretching the film in the lateral direction while holding the film edge with a tenter, so that the film is constrained in the longitudinal / lateral direction. High temperature can be applied while maintaining Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer is improved, and the coating layer and the polyester film are firmly adhered. For example, as an easily-adhesive polyester film, the uniformity of the coating layer, the improvement of the film-forming property, and the adhesion between the coating layer and the film often produce favorable characteristics.

In this case, the coating solution to be used is preferably an aqueous solution or an aqueous dispersion from the viewpoint of handling, working environment, and safety, but may contain an organic solvent.

Next, the coating layer provided on the film in the present invention will be described. This coating layer is formed from a coating solution containing a specific polyurethane.

The polyurethane in the present invention is a polyurethane having as a constituent component a copolymerized polycarbonate polyol having a structure in which two types of carbonate diols having different main chain structures are copolymerized.

Polycarbonate polyol is obtained, for example, by a reaction from diphenyl carbonate and diol, a reaction from dialkyl carbonate and diol, or a reaction from alkylene carbonate and diol.

For example, examples of the diol component used in the above reaction include the following. 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol 1,10-decanediol, neopentyl glycol, cyclohexanediol and the like.

The copolymerized polycarbonate polyol in the present invention is formed by, for example, adding carbonate to these diol components to form a monomer unit having carbonate at the terminal, and copolymerizing two or more of these monomer units, or two or more diols. It can be obtained by a method such as copolymerization while adding carbonate to the component. These copolymer polycarbonate polyols are used as a polyol component of polyurethane.

The copolymerized polycarbonate polyol constituting the copolymerized polycarbonate polyurethane is usually 100 to 3000, preferably 200 to 2500, and more preferably 400 to 2000 in terms of polystyrene-reduced number average molecular weight (Mn) by gel permeation chromatography (GPC). It is. When it is larger than this range, the blocking resistance is deteriorated, and when it is smaller than this range, the adhesion may be inferior.

Further, the structure of these copolymers is not particularly limited, such as random copolymerization, graft copolymerization, and block copolymerization.

The polyurethane in the present invention may contain other polyol (for example, polyether diol, polyester diol, etc.) as long as it contains the above-described copolymer polycarbonate polyol.

The polyisocyanate component of the polyurethane in the present invention is not particularly limited, but mainly comprises aliphatic and alicyclic groups. Specifically, it is preferable that 50 mol% or more of all the polyisocyanate components is an aliphatic or alicyclic polyisocyanate.

Examples of polyisocyanate components include isophorone diisocyanate, 1,6 hexamethylene diisocyanate, triene diisocyanate, hydrogenated diphenylmethane diisocyanate, trans-1,4-cyclohexylene diisocyanate, 4,7-dimer acid diisocyanate, lysine diisocyanate, 1,6 -Diisocyanato-2,2,4-trimethylhexane, cyclohexane-1,3-diyl diisocyanate, cyclohexane-1,4-diyl diisocyanate, cyclohexane-1,3-diylbis (methyl isocyanate), 1-methylcyclohexane-2,4 -Diyl diisocyanate, methyl 2,6-diisocyanatohexanoate, tetramethylene diisocyanate and the like.

When 50 mol% or more of all the polyisocyanate components is an aromatic polyisocyanate, the adhesiveness, appearance, and transparency may be inferior.

In the present invention, the polyurethane containing the copolymerized polycarbonate as a constituent component may be one using a solvent as a medium, but preferably using water as a medium. In order to disperse or dissolve polyurethane in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into a polyurethane resin, and a water-soluble type. In particular, the self-emulsification type in which a hydrophilic group is introduced into the skeleton of the polyurethane resin is preferable because of excellent storage stability of the liquid and water resistance and transparency of the resulting coating layer.

Further, examples of the hydrophilic group to be introduced include various groups such as a carboxyl group, a sulfone group, phosphoric acid, phosphonic acid, quaternary ammonium, and polyethylene glycol.

The amount of hydrophilic groups in the polyurethane is preferably 0.05% by weight to 8% by weight. When the amount of the hydrophilic group is small, the water solubility or water dispersibility of the polyurethane is poor, and when the amount of the hydrophilic group is large, the water resistance of the coating layer after coating is poor, or the film tends to stick to each other due to moisture absorption. Because there are things.

The coating liquid in the present invention may contain components other than those described above as necessary. For example, surfactants, other binders, crosslinking agents, antifoaming agents, coatability improvers, thickeners, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like. These additives may be used alone or in combination of two or more as necessary.

The coating layer formed using a crosslinking agent as a component of the coating solution is excellent in terms of easy adhesion to the top coat in addition to excellent adhesion after solvent treatment. Various crosslinking agents are used, and examples thereof include carbodiimide compounds, oxazoline compounds, melamine compounds, epoxy compounds, and isocyanate compounds. The amount of the crosslinking agent is usually 5 to 60% by weight, preferably 10 to 60% by weight, and more preferably 20 to 50% by weight as a ratio in the nonvolatile component of the coating solution. When outside this range, the appearance and adhesion of the resulting coating layer may be inferior.

The carbodiimide compound is a compound having a carbodiimide group in the molecule and a reaction product thereof. As the compound having a carbodiimide group in the molecule, a polycarbodiimide compound having two or more carbodiimide groups in the molecule is particularly suitable. For example, in JP-A-10-316930 and JP-A-11-140164 As shown, an organic polyisocyanate, particularly preferably an organic diisocyanate, is produced as the main synthetic raw material.

Examples of these diisocyanates include 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1-methylphenylene-2,4-diisocyanate, 1-methoxyphenylene-2,4-diisocyanate, and 2,4-tolylene diene. Isocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, biphenylene-4,4′-diisocyanate, 3,3′-dimethoxybiphenylene-4,4′-diisocyanate, 3,3′-dimethylbiphenylene-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate, 3,3′-dimethoxydiphenylmethane-4,4′-diisocyanate 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, naphthylene-1,5-diisocyanate, cyclobutylene-1,3-diisocyanate, cyclopentylene-1,3-diisocyanate, cyclohexylene-1,3 -Diisocyanate, cyclohexylene-1,4-diisocyanate, 1-methylcyclohexylene-2,4-diisocyanate, 1-methylcyclohexylene-2,6-diisocyanate, 1-isocyanate-3,3,5-trimethyl-5- Isocyanate methylcyclohexane, cyclohexane-1,3-bis (methylisocyanate), cyclohexane-1,4-bis (methylisocyanate), isophorone diisocyanate, dicyclohexylmethane-2,4′-diisocyanate, Cyclohexylmethane-4,4′-diisocyanate, ethylene diisocyanate, 2,6-diisopropylphenyl isocyanate, tetramethylene-1,4-diisocyanate, hexamethylene diisocyanate, dodecamethylene-1,12-diisocyanate, lysine diisocyanate methyl ester, 1, And 5-naphthalene diisocyanate.

In the production of polycarbodiimide, one or a mixture of two or more of these organic diisocyanates can be used. Moreover, organic polyisocyanate other than diisocyanate can also be used. Furthermore, monomers other than these may be included as a copolymerization component in the molecule.

An oxazoline compound is a compound having at least one oxazoline ring in the molecule. Also included are monomers having an oxazoline ring and polymers synthesized using an oxazoline compound as one of the raw material monomers. The compound having at least one oxazoline ring in the molecule is particularly preferably a polymer containing an oxazoline group, and can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition-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, Examples thereof include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like, and one or a mixture of two or more thereof can be used. Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not particularly limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, (Meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide (As the alkyl group, unsaturated amides such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); Vinyl esters such as vinyl and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; Halogen-containing α, β-unsaturated such as vinyl chloride, vinylidene chloride and vinyl fluoride Monomers: α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene can be used, and one or more of these monomers can be used.

A melamine compound is a compound having a melamine skeleton in the compound. For example, an alkylolated melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and a mixture thereof can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

An epoxy compound is a compound having an epoxy group in the molecule. Examples include condensates of epichlorohydrin with hydroxyl groups and amino groups such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, and bisphenol A, and polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. is there. 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, 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, poly Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N ′,-tetraglycidyl-m-. Examples include xylylenediamine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

An isocyanate compound is a compound having an isocyanate group in the molecule. In particular, it is preferable to use a polyfunctional isocyanate compound containing two or more isocyanate groups in one molecule. Examples of the polyfunctional isocyanate compound include low or high molecular aromatic, aliphatic diisocyanate, and trivalent or higher polyisocyanate. Examples of the polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate. , Hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate and trimers of these isocyanate compounds. Further, an excess amount of these isocyanate compounds and low molecular active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, poly Examples thereof include terminal isocyanate group-containing compounds obtained by reacting polymer active hydrogen compounds such as ether polyols and polyamides. In addition, when using an isocyanate compound as a crosslinking agent, it is also possible to use a block type isocyanate compound. The blocked isocyanate can be prepared by subjecting the above isocyanate compound and blocking agent to an addition reaction by a conventionally known appropriate method. Examples of the isocyanate blocking agent include phenols such as phenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; thiophenols such as thiophenol and methylthiophenol; oximes such as acetoxime, methyl etiketooxime, and cyclohexanone oxime. Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; tertiary alcohols such as t-butanol and t-pentanol ; Lactams such as ε-caprolactam, δ-valerolactam, ν-butyrolactam, β-propyllactam; aromatic amines; imides; acetylacetone, acetoacetate Active methylene compounds such as malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; sodium bisulfite, and the like.

In the present invention, particles may be contained in the coating solution in order to give the film slidability or reduce blocking. If the particle content is too large, the transparency of the coating layer may decrease, the continuity of the coating layer may be impaired, and the coating strength may decrease, or the easy adhesion may decrease. In the non-volatile component of the liquid, usually 15% by weight or less, further 10% by weight or less is suitable. Moreover, there is no limitation in particular about the minimum of particle content.

As the particles to be used, for example, inorganic particles such as silica, alumina, and metal oxide, or organic particles such as crosslinked polymer particles can be used. In particular, silica particles are suitable from the viewpoint of dispersibility in the coating solution and transparency of the resulting coating film.

If the particle diameter is too small, the effect of reducing blocking is difficult to obtain, and if it is too large, the film tends to fall off. The average particle size is preferably about 1/2 to 10 times the thickness of the coating layer. Furthermore, if the particle size is too large, the transparency of the coating layer may be inferior, so the average particle size is preferably 300 nm or less, and more preferably 150 nm or less. The average particle diameter of the particles described here can be obtained by measuring the 50% average diameter of the number average of the particle dispersion with Microtrac UPA (Nikkiso Co., Ltd.).

As a method of applying the coating solution to the polyester film, for example, a coating technique as shown in “Coating system” published by Yuji Harasaki, Tsuji 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 roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, calendar coater And techniques such as an extrusion coater and a bar coater.

In addition, in order to improve the applicability of the coating agent to the film, the film may be subjected to chemical treatment, corona discharge treatment, plasma treatment or the like before coating.

The coating amount of the coating layer provided on the polyester film is usually from 0.002 to 1.0 g / m ² , preferably from 0.005 to 0.5 g / m as a final coating (as dry solid content). ² and more preferably 0.01 to 0.2 g / m ² . If the coating amount is less than 0.002 g / m ^2, sufficient adhesion performance may not be obtained. If the coating layer exceeds 1.0 g / m ² , the appearance / transparency deteriorates, film blocking, Cost may increase.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, the evaluation method in an Example and a comparative example is as follows.

(1) Measurement of intrinsic viscosity of polyester:
1 g of polyester from which other polymer components and pigments incompatible with polyester were removed was precisely weighed, 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added and dissolved, and measurement was performed at 30 ° C.

(2) Average particle diameter (d50) of particles added to the polyester film:
The particle size was measured by a sedimentation method based on Stokes' resistance law using a Shimadzu centrifugal sedimentation type particle size distribution analyzer SA-CP3 type.

(3) Adhesiveness after solvent treatment:
The coating layer of the polyester film was rubbed with cotton soaked with MEK (methyl ethyl ketone), and the solvent resistance adhesion between the coating layer after rubbing with MEK and UV ink was tested by the following method. That is, a cotton film in which MEK was sufficiently impregnated was placed on the polyester film coating layer, and a load of 450 g / cm ² was applied thereon to perform a rubbing test. The rubbing was performed under three conditions of 1 round trip, 3 round trips, and 5 round trips. A rubbing tester manufactured by Ohira Rika Kogyo Co., Ltd. was used for the rubbing test.

Next, on the coating layer subjected to the rubbing test with MEK, UV curable ink FD Carton X black M manufactured by Toyo Ink Manufacturing Co., Ltd. was applied with an RI tester manufactured by IHI Machine Systems Co., Ltd., and the coating thickness was 1 μm. And the ink was cured using a 160 W / cm metal halide lamp to prepare a laminated film. The integrated light quantity of the active energy ray applied when curing was 90 mJ / cm ² .

A crosscut was made in the ink layer of the laminated film prepared by the above method, and a peel test was performed using a cello tape (registered trademark), and the adhesion between the coating layer after rubbing with a solvent and the UV ink was evaluated. The evaluation of adhesiveness was performed in the following five stages A to E. A indicates the highest class and E indicates the lowest class.

A: UV ink does not peel off and is good B: UV ink partially peels off C: About half of UV ink peels off D: UV ink almost peels off E: UV ink peels off on the entire surface

(4) Adhesiveness to topcoat:
Three types of top coats having different characteristics shown below were coated on a polyester film coating layer to prepare a laminated film. After making a laminated film, the adhesiveness evaluation with respect to various topcoats was performed.

-Adhesion I:
On the polyester film coating layer, an acrylic HC adjustment liquid was applied to evaluate the adhesion. For adjustment of acrylic HC, “Karayad DPHA” (manufactured by Nippon Kayaku Co., Ltd.) / “Karayad R-128H” (manufactured by Nippon Kayaku Co., Ltd.) / “Irgacure 651” (manufactured by Ciba Specialty Chemicals) = 80/20/5 weight Mix in proportion and adjust to 30% solution with toluene. This coating solution was applied using an automatic coater (PI1210) manufactured by Tester Sangyo Co., Ltd. so that the dry film thickness was 5 μm. The coated film was dried under heating conditions at 80 ° C. for 1 minute, and then cured using a 120 W / cm metal halide lamp to prepare a laminated film. The integrated light quantity of the active energy ray applied when curing was 220 mJ / cm ² .

-Adhesion II:
On the polyester film coating layer, UV curable ink FD Carton X Black M and FD Carton X Indigo M manufactured by Toyo Ink Manufacturing Co., Ltd. are coated with an RI tester, an offset printing tester manufactured by IHI Machinery Systems. Then, a coating thickness of 1 μm was provided, and the ink was cured using a 160 W / cm metal halide lamp to prepare a laminated film. The integrated light quantity of the active energy ray applied when curing was 90 mJ / cm ² .

-Adhesion III:
“Diabeam UR-6530” (manufactured by Mitsubishi Rayon Co., Ltd.), which is an active energy ray curable resin, is dropped on a flat SUS plate, and the evaluation surface of the polyester film is in contact with the active energy ray curable resin from above. The laminated film was prepared by using a 160 W / cm high-pressure mercury lamp and curing the ink using a roller having a load of 4 kg and a width of 50 mm so that the thickness after curing was 15 μm. The integrated light quantity of the active energy ray applied when curing was 160 mJ / cm ² .

For the above adhesives I to III, a cross-cut was made in the top coat layer of the resulting laminated film so that there were 100 grids in a 1-inch width, and a quick peel test with cello tape (registered trademark) was conducted to peel off The adhesion was evaluated by area. Evaluation was performed in five stages A to E shown below.

A: Number of cross-cuts peeled = 0
B; 1 ≦ number of cross-cuts ≦ 10
C: 11 ≦ number of cross cuts ≦ 20
D: 21 ≦ Number of cross-cuts peeled E: Full peel

(5) Transparency-1:
The turbidity (haze) of the film was measured using a turbidimeter “NDH2000” (manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K 7136 (ISO14782). It can be said that the lower the haze, the better the transparency.

(6) Transparency-2:
In the transparency-1 evaluation method, the turbidity (haze) of a film provided with a coating layer was measured, and the increase in haze relative to a film without the coating layer measured in the same manner was determined. It can be said that the transparency of a coating layer is excellent, so that the raise of the haze by providing a coating layer with respect to the film which does not provide a coating layer is small. The evaluation of transparency was performed in the following two stages A and B.
A: Haze increase is less than 0.3% B: Haze increase is 0.3% or more

(7) Blocking resistance:
Two polyester films to be measured are prepared, and the surface of one film provided with the coating layer is overlapped with the surface of the other film not provided with the coating layer, and an area of 12 cm × 10 cm is pressed. The conditions are 40 ° C., 80% RH, 10 kg / cm ² , 20 hours. Thereafter, the films are peeled off according to the method specified in ASTM-D-1893, and the peel load is measured. It can be said that the lighter the peeling load, the better the blocking. When the load exceeds 150 g / 10 cm, there may be a problem in practice. In addition, when the coating layer is provided on both surfaces, a film without another coating layer can also be used.

The polyester raw materials used in Examples and Comparative Examples are as follows.
(Polyester 1): Polyethylene terephthalate having an intrinsic viscosity of 0.66 substantially containing no particles (Polyester 2): Intrinsic viscosity containing 0.6 parts by weight of amorphous silica having an average particle diameter (d50) of 2.5 μm 0.66 polyethylene terephthalate (polyester 3): polyethylene terephthalate having an intrinsic viscosity of 0.65 containing 0.3% by weight of amorphous silica having an average particle diameter (d50) of 1.6 μm

Moreover, the following was used as a coating composition. However, “part” in the text represents the weight ratio of the active ingredient.

(U1): 400 parts of a polycarbonate polyol composed of 1,6-hexanediol and diethyl carbonate having a number average molecular weight of 2000, 10.4 parts of neopentyl glycol, 58.4 parts of isophorone diisocyanate, and 74. parts of dimethylolbutanoic acid. Water dispersion of polyurethane resin obtained by neutralizing 3 parts of prepolymer with triethylamine and extending chain with isophoronediamine

(U2): Prepolymer comprising 320 parts of polycarbonate polyol composed of 1,6-hexanediol and diethyl carbonate having a number average molecular weight of 800, 505.7 parts of hydrogenated diphenylmethane diisocyanate, and 148.6 parts of dimethylolbutanoic acid. Water dispersion of polyurethane resin obtained by neutralization with triethylamine and chain extension with isophoronediamine

(U3) Ether polyurethane product "Takelac WS6021" (Mitsui Chemicals)
(U4) 160 parts of polycarbonate diol having a number average molecular weight of about 800 obtained by copolymerizing structural units of the following formulas (2) and (3) at a ratio of 50 mol% / 50 mol%, hydrogenated diphenylmethane An aqueous dispersion of urethane resin obtained by neutralizing a prepolymer comprising 78.6 parts of diisocyanate and 6.7 parts of dimethylolpropionic acid with triethylamine and extending the chain with 8.4 parts of isophoronediamine.

(U5) F2967D (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which is a polyurethane mainly comprising an alicyclic polyisocyanate as a polyisocyanate component, having a copolymerized polycarbonate polyol as a constituent component
(U6) 202 parts of polycarbonate diol having a number average molecular weight of about 1000 obtained by copolymerizing structural units of the following formulas (1) and (3) at a ratio of 70 mol% / 30 mol%, and hydrogenated diphenylmethane An aqueous dispersion of urethane resin obtained by neutralizing a prepolymer comprising 78.6 parts of diisocyanate and 6.7 parts of dimethylolpropionic acid with triethylamine and extending the chain with 6.5 parts of dipropylenetriamine

(S) Silica sol aqueous dispersion having an average particle size of 0.07 μm

(C1): Carbodiimide group-containing crosslinking agent: Carbodilite V02 (Nisshinbo Co., Ltd.)
(C2): Carbodiimide group-containing crosslinking agent: Carbodilite E02 (Nisshinbo Co., Ltd.)
(C3): Melamine group-containing crosslinking agent: Becamine MAS (manufactured by Dainippon Ink & Chemicals, Inc.)
(C4): Isocyanate group-containing crosslinking agent: Elastolon MF25K (Daiichi Kogyo Seiyaku Co., Ltd.)
(C5): “Epocross WS-700” (manufactured by Nippon Shokubai Co., Ltd.), which is a polymer type crosslinking agent having an oxazoline group branched to an acrylic resin
(C6): “Epocross WS-500” which is a polymer type crosslinking agent having an oxazoline group branched to an acrylic resin (manufactured by Nippon Shokubai Co., Ltd., containing about 38% by weight of 1-methoxy-2-propanol solvent)
(C7): “Epocross WS-300” (manufactured by Nippon Shokubai Co., Ltd.), which is a polymer type crosslinking agent having an oxazoline group branched to an acrylic resin
(C8): “Denacol EX-521” (manufactured by Nagase ChemteX Corporation) which is polyglycerol polyglycidyl ether
(C9): A compound comprising 312.5 parts of hexamethylene diisocyanate trimer and 55.4 parts of methoxypolyethylene glycol having a number average molecular weight of 700, and containing a urethane bond and a terminal isocyanate group in the molecule, Blocked isocyanate compounds blocked with MEK oxime

Comparative Example 1:
Polyester 1 and polyester 2 are blended at a weight ratio of 95/5, dried thoroughly, melted by heating to 280-300 ° C, extruded into a sheet form from a T-shaped die, and the surface using an electrostatic adhesion method. An unstretched polyethylene terephthalate film was prepared by cooling and solidifying while closely contacting a mirror surface cooling drum having a temperature of 40 to 50 ° C. This film was stretched 3.7 times in the longitudinal direction while passing through a heating roll group at 85 ° C. to obtain a uniaxially oriented film. The coating composition as shown in Table 1 was applied to one side of this uniaxially oriented film. Next, this film was guided to a tenter stretching machine, and the coating composition was dried using the heat, and stretched 4.0 times in the width direction at 100 ° C., and further heat-treated at 230 ° C., and the film thickness was 38 μm. A laminated polyester film having a 0.05 g / m ² coating layer on a biaxially oriented polyethylene terephthalate film was obtained. Table 1 shows the coating solution composition and film characteristics of this film.

Comparative Examples 2 and 3:
In the same process as Comparative Example 1, a coating film was obtained in which the coating layer shown in Table 1 was provided on a base film having a film thickness of 38 μm. The properties of this film are shown in Table 1.

Comparative Example 4:
In the same process as Comparative Example 1, a film was obtained in which a coating layer was not provided on a base film having a film thickness of 38 μm. The solvent resistance was very poor.

Examples 1 to 4:
In the same process as Comparative Example 1, a coating film was obtained in which the coating layer shown in Table 1 was provided on a base film having a film thickness of 38 μm. The properties of this film are shown in Table 1. By applying the copolymer-type polycarbonate polyurethane, the properties of the coating layer were not lost even after the solvent treatment, and a result of excellent adhesion was obtained.

Comparative Example 5:
A blend of polyester 1 and polyester 3 at a weight ratio of 92/8 was used as the raw material for layer A, and polyester 1 alone was used as the raw material for layer B. To the outer layer (surface layer) and the B layer as an intermediate layer, and coextruded in a layer configuration of two types and three layers (A / B / A) using an electrostatic adhesion method. The film was cooled and solidified while being in close contact with a mirror-surface cooling drum having a surface temperature of 40 to 50 ° C. to prepare an unstretched polyethylene terephthalate film having a thickness composition ratio of A / B / A = 3/94/3. This film was stretched 3.7 times in the longitudinal direction while passing through a heating roll group at 85 ° C. to obtain a uniaxially oriented film. Next, this film was guided to a tenter stretching machine, stretched 4.0 times in the width direction at 100 ° C., further heat treated at 230 ° C., and then subjected to a relaxation treatment of 2% in the width direction. An axially oriented polyethylene terephthalate film was obtained. The properties of this film are shown in Table 2.

Reference example 1:
The coating composition as shown in Table 2 was applied to one side of the uniaxially oriented film obtained in Comparative Example 5. Next, the film was guided to a tenter stretching machine, and the coating composition was dried using the heat. Thereafter, in the same process as Comparative Example 1, the film thickness was 100 μm on a biaxially oriented film as shown in Table 2. A laminated polyester film provided with the coating layer shown was obtained. The properties of this film are shown in Table 2.

Examples 5-11:
In the same process as in Reference Example 1, a laminated polyester film was obtained in which the coating layer shown in Table 2 was provided on a base film having a film thickness of 100 μm. Adequate adhesion could be obtained by using in combination with a carbodiimide-based crosslinking agent.

Example 12:
A blend of polyester 1 and polyester 3 at a weight ratio of 92/8 was used as the raw material for layer A, and polyester 1 alone was used as the raw material for layer B. To the outer layer (surface layer) and the B layer as an intermediate layer, and coextruded in a layer configuration of two types and three layers (A / B / A) using an electrostatic adhesion method. The film was cooled and solidified while being in close contact with a mirror-surface cooling drum having a surface temperature of 40 to 50 ° C. to prepare an unstretched polyethylene terephthalate film having a thickness composition ratio of A / B / A = 3/94/3. This film was stretched 3.7 times in the longitudinal direction while passing through a heated roll group at 85 ° C. to obtain a uniaxially oriented film. The coating composition as shown in Table 3 was applied to one side of this uniaxially oriented film. Next, this film was guided to a tenter stretching machine, stretched 4.0 times in the width direction at 100 ° C., further heat treated at 230 ° C., and then subjected to a relaxation treatment of 2% in the width direction. On the axially oriented polyethylene terephthalate film, a laminated polyester film was obtained in which a coating layer having the coating amount shown in Table 3 was provided. The properties of this film are shown in Table 3.

Examples 13 to 22:
In the same process as Example 12, the coating solution was changed as shown in Table 3 to obtain a coated film in which the coating layer of the amount shown in Table 3 was provided on a base film having a film thickness of 100 μm. The properties of this film are shown in Table 3.

Examples 23-31:
In the same process as Example 12, the coating solution was changed as shown in Table 4 to obtain a coated film in which the coating layer of the amount shown in Table 4 was provided on a base film having a film thickness of 100 μm. The properties of this film are shown in Table 4.

The coated film of the present invention includes packaging materials, plate making materials, display materials, transfer materials, window paste materials, antireflection films used for membrane switches and flat displays, optical films such as diffusion sheets and prism sheets, transparent It can be suitably used for applications such as a touch panel.

Claims

A coating film having a coating layer formed from a coating solution containing polyurethane on the surface of a polyester film, wherein the polyurethane is a polycarbonate polyol in which two types of carbonate diols having different main chain structures are copolymerized. A coated film, characterized by being a polyurethane having.
The coated film according to claim 1, wherein the polyisocyanate constituting the polyurethane is an aliphatic or alicyclic polyisocyanate, and the proportion thereof is 50 mol% or more in the total polyisocyanate component.
The coating film according to claim 1 or 2, wherein the coating solution further contains a crosslinking agent.
The coated film according to any one of claims 1 to 3, wherein the crosslinking agent is a carbodiimide compound and / or an oxazoline compound.
The coated film according to claim 4, wherein the ratio of the crosslinking agent is 5 to 60% by weight as a ratio in the nonvolatile component of the coating liquid.