TW201514008A - Method for producing hard coat film - Google Patents

Abstract

A method for producing a hard coat film with high hardness, which includes a hard coat layer having excellent weather resistance and scratch resistance, is provided. The method is easy and simple, while reducing environmental load. The method for producing a hard coat film including a hard coat layer on at least one surface of a thermoplastic resin film is characterized by going through a step of in-line coating an aqueous hard coat agent on at least one surface of the thermoplastic resin film.

Description

Hard coating film manufacturing method

The present invention relates to a method of producing a hard coat film.

More specifically, it relates to a method of producing a hard coat film comprising a hard coat layer having excellent scratch resistance and high hardness on at least one surface of a thermoplastic film.

The thermoplastic film represented by the polyester film is excellent in various properties such as dimensional stability, mechanical strength, heat resistance, transparency, and electrical insulating properties, and thus is used as a base film for a wide range of applications. When the thermoplastic film is applied to, for example, a surface protective film of a flat panel display, a protective film of a solar cell, or the like, a cured film is formed on the surface of the film for the purpose of improving weather resistance and scratch resistance of the surface of the film. After use.

Forming a cured film on the surface of the film is known as a method in which a composition obtained by dissolving in an organic solvent and containing a film-forming component is applied onto the surface of the film, followed by heating or light irradiation, thereby performing film formation (patent Document 1 and Patent Document 2). These are excellent techniques for easily forming a cured film having a high hardness. However, since it is necessary to use an organic solvent, there is a disadvantage that inevitably responds to problems such as work environment management, waste liquid treatment, and environmental burden.

In order to solve the above problems, several methods using a curable composition in which an aqueous medium is used as the curable composition have been proposed. For example, in Patent Document 3 discloses a method of using an aqueous curable composition containing a bio-derived material as a main component; and Patent Document 4 discloses an aqueous curable composition using a partially alkalized polyvinyl alcohol as a binder component. The method of things. However, the cured film formed by the technique of Patent Document 3 is inferior in weather resistance; the hardness of the cured film formed by the technique of Patent Document 4 is poor; and the required performance as a hard coat agent cannot be satisfied.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-286925

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-122267

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-221457

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2004-272190

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2008-524402

The present invention has been made to improve the above-mentioned situation, and an object of the present invention is to provide a method for producing a hard coat film having a high hardness including a hard coat layer excellent in weather resistance and scratch resistance, which is simple and simple, and reduces environmental burden.

According to the present invention, the objects and advantages of the present invention can be achieved by the following methods: A method for producing a hard coat film, which is a method for producing a hard coat film comprising a hard coat layer on at least one side of a thermoplastic resin film, characterized in that it passes through at least one line of the thermoplastic resin film (in -line) a step of applying an aqueous hard coating agent.

According to the method of the present invention, it is possible to easily produce a hard coat film having a high hardness of a hard coat layer excellent in weather resistance and scratch resistance on at least one surface of a thermoplastic film by a simple and simple method.

Since the method of the present invention is a simple and simple method for reducing the environmental burden, it contributes to reducing the manufacturing cost of the hard coat film and also conforms to the concept of environmental protection.

The hard coat film obtained by the present invention is excellent in properties such as weather resistance, scratch resistance, heat resistance, transparency, and chemical resistance because of the high hardness of the hard coat layer, and therefore, in addition to the surface protective film use of, for example, a flat panel display, In addition to the protective film use of the solar cell, the use of the antireflection film, and the use of the protective film of the touch panel, it can be suitably applied to applications such as building materials and vehicles.

The method for producing a hard coat film of the present invention is a method of applying a step of applying an aqueous hard coat agent to at least one side of a thermoplastic resin film.

<Thermoplastic resin film>

In the present invention, a thermoplastic resin film is used as the substrate film.

Examples of the material constituting the thermoplastic resin film include polyester, polyolefin (for example, polypropylene), polyamine, polyphenylene sulfide, and (meth)acrylic resin (for example, polymethyl methacrylate). Alternatively, a triacetyl cellulose (TAC) film, a polyacrylonitrile (PAN) film, a film containing polyvinyl alcohol, or the like may be used. Among these, a polyester film is preferably used from the viewpoints of dimensional stability, transparency, mechanical strength and the like.

The thermoplastic resin film used in the present invention may include polyethylene terephthalate, polypropylene terephthalate, or polybutylene terephthalate. Poly(ethylene naphthalate), poly(propylene naphthalate), and polycarbonate, and copolymers of copolymers containing each of these as a main component For the ester film or the like, it is preferred to use one or more selected from the group consisting of, and more preferably, a polyethylene terephthalate, a polytrimethylene terephthalate or a polybutylene terephthalate. A polyester film of an ester, polyethylene naphthalate, and poly(naphthalene dicarboxylate).

The thermoplastic resin film in the present invention may be a laminate film comprising a plurality of layers. Each of the layers in the laminated body film may contain the same kind of thermoplastic resin, and may also contain different kinds of thermoplastic resins.

These thermoplastic resins may contain known additives such as a light stabilizer, an antioxidant, an ultraviolet absorber, a flame retardant, a slip agent (fine particles), a crystallization agent, and crystallization in a range that does not impair the effects of the present invention. Inhibitors, etc.

The thickness of the thermoplastic resin film in the present invention will be described later.

<hard coating agent>

The hard coating agent used in the present invention is an aqueous hard coating agent. That is, each component contained in the hard coating agent is a reagent in a state of being dissolved or dispersed in an aqueous medium. The aqueous medium is a medium containing only water or a medium comprising a mixture of water and a water-soluble organic medium.

The hard coat agent in the present invention preferably contains (A) a polyfunctional (meth) acrylate, (B) a surfactant, and (C) an aqueous medium, and optionally further contains (D) a polyester, ( E) a crosslinking agent, (F) a polymerization initiator, and the like.

[(A) Polyfunctional (meth) acrylate]

The (A) polyfunctional (meth) acrylate in the hard coating agent is more preferably an aliphatic polyol or a dimer (meth) acrylate thereof, and has two or more molecules in the molecule (methyl) A polyfunctional (meth) acrylate compound of an acrylonitrile group.

Specific examples of the polyfunctional acrylate compound include ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, and 1,4. - Butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(methyl) Acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, bis(2-hydroxyethyl)isocyanato Examples of the ester di(meth)acrylate; and the trifunctional compound may, for example, be trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerol tri(meth)acrylate, or the like. (2- Hydroxyethyl)isomeric isocyanate tri(meth)acrylate or the like; examples of the tetrafunctional or higher compound include pentaerythritol tetra(meth)acrylate, dipentaerythritol penta (meth)acrylate, and dipentaerythritol VI ( Methyl) acrylate, di-trimethylolpropane tetra(meth) acrylate, etc., and a compound having four or more functional groups, for example, may be used, for example, having four or more (meth) acrylonitrile groups in the molecule. An oligoester (meth) acrylate, an oligoether (meth) acrylate having four or more (meth) acryl fluorenyl groups in the molecule, and having four or more molecules in the molecule (A) A poly(meth)acrylate such as an acryloyl group-containing oligo-epoxy (meth) acrylate or the like, and a compound obtained by adding ethylene oxide or propylene oxide to a hydroxyl group of the compounds.

As the (A) polyfunctional (meth) acrylate in the invention, it is preferred to use dipentaerythritol hexa(meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol IV selected from the above. One or more kinds of (meth) acrylate and di-trimethylolpropane tetra(meth) acrylate.

Commercial products of the polyfunctional (meth) acrylate as described above, for example, Aronix M-208, M-210, M-211B, M-215, M-220, M-225 manufactured by Toagosei Co., Ltd. , M-270, M-240, M-309, M-310, M-321, M-350, M-360, M-313, M-315, M-306, M-305, M-303, M -452, M-450, M-408, M-403, M-400, M-402, M-404, M-406, M-405, M-460, M-510, M-520, M-1100 , M-1200, M-320, M-233, M-245, M-260, M-1210, M-1310, M-1600, M-221, M-203, TO-924, TO-1270, TO-1231, TO-595, TO-756, TO-1343, TO- 902, TO-904, TO-905, TO-1330, TO-1382, etc.; KAYARAD R-526, NPGDA, PEG400DA, FM-400, R-167, HX-220, HX- manufactured by Nippon Kayaku Co., Ltd. 620, R-551, R-712, R-604, R-684, GPO-303, TMPTA, THE-330, TPA-320, TPA-330, PET-30, T-1420, RP-1040, DPHA, MAX-3510, DPEA-12, DPHA-2C, DPHA-40H, D-310, D-330, DPCA-20, DPCA-30, DPCA-60, DPCA-120, DN-0075, DN-2475, TC- 120S, SR-295, SR-355, SR-399E, SR-494, SR-9041, SR-368, SR-415, SR-444, SR-454, SR-492, SR-499, SR-502, SR-9020, SR-9035, SR-111, SR-212, SR-213, SR-230, SR-259, SR-268, SR-272, SR-344, SR-349, SR-601, SR- 602, SR-610, SR-9003, KS-HDDA, KS-TPGDA, KS-TMPTA, etc.; A-9300, A-TMM-3, A-TMPT, AD-TMP, A manufactured by Shin-Nakamura Chemical Co., Ltd. -TMMT, A-9550, A-DPH, etc.; Light acrylate 1,9-ND-A, PE-4A, DPE-6A, etc. manufactured by Kyoeisha Chemical Co., Ltd.

The polyfunctional (meth) acrylate which is preferably used in the present invention preferably has a (meth)acrylic group equivalent of 1,000 g/eq or less, more preferably 50 g/eq to 600 g/eq. By using a polyfunctional (meth) acrylate having a (meth)acrylic group equivalent of 1,000 g/eq or less, the scratch resistance and hardness of the formed hard coat layer can be improved.

In the present invention, the (meth)acrylic group equivalent means a molecular weight per 1 mol of (meth)acryl fluorenyl group, and is a value represented by the following formula: (molecular weight of the polyfunctional acrylate compound) / ( The number of (meth)acrylonitrile groups per 1 molecular weight polyfunctional acrylate compound).

In the present invention, only a polyfunctional acrylate having the same (meth)acrylic group equivalent can be used, and a mixture of a plurality of polyfunctional acrylates having different (meth)acrylic group equivalents can also be used. In the latter case, the (meth)acrylic equivalent of the polyfunctional acrylate can be evaluated as the average of the total mixture.

In the present invention, in particular, a hard coat layer having an extremely high hardness can be obtained by using a polyfunctional (meth) acrylate having a (meth)acrylic group equivalent of 1,000 or less. In this case, it is preferred to use a polyfunctional (meth)acrylic group equivalent of 1,000 or less based on the total amount of the (A) polyfunctional (meth) acrylate (A). Base) acrylate.

The ratio of use of (A) polyfunctional (meth) acrylate in the hard coating agent used in the present invention is relative to (A) polyfunctional (meth) acrylate and (B) surfactant, and in use. In the case of the total of (F) polymerization initiator, it is preferably 5% by mass to 99% by mass, more preferably 10% by mass to 97% by mass, still more preferably 20% by mass to 95% by mass. quality%. By using the ratio of use in this range, the applicability of the hard coating agent can be maintained, and the hardness of the hard coat layer can be increased.

[(B) surfactant]

The hard coat agent in the present invention preferably contains (B) a surfactant.

The (B) surfactant contained in the hard coating agent is preferably an anionic surfactant containing an alkylene chain, and more preferably a compound represented by the following formula (1).

XO-(R ¹ O) _n -R ² (1)

(In the formula (1), X is a group having an aromatic ring, R ¹ is an alkylene group having a carbon number of 2 to 4, and R ² is a hydrogen atom, PO(OM) ₂ or SO ₃ M (wherein M Is a hydrogen atom, an ammonium ion or a metal ion), and n is an integer from 5 to 150)

Examples of the aromatic ring in X include a benzene ring, a naphthalene ring and the like, and a benzene ring is preferred. X is particularly preferably a group represented by the following formula (2).

(In the formula (2), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group, m is an integer of 1 to 3, and "*" represents a bond)

In the formula (2), the alkyl group of R ³ and R ⁴ is preferably an alkyl group having 1 to 3 carbon atoms, and each of them may independently be, for example, a methyl group, an ethyl group, a n-propyl group or the like. Particularly preferred for R ³ and R ⁴ are independently methyl or ethyl.

The alkylene group of R ¹ may, for example, be a 1,2-extended ethyl group, a 1,2-extended propyl group, a 1,3-propenyl group, a 1,4-tert-butyl group or a 1,3-butylene group. The metal ion in M in R ² is preferably a monovalent cation, and examples thereof include alkali metal ions such as sodium ion, potassium ion, and lithium ion.

The (B) surfactant in the hard coating agent may be a compound represented by the above formula (1), or a compound represented by the formula (1) may be used in combination with other surfactants.

As the other surfactant used herein, a known emulsifier can be suitably exemplified, and for example, a nonionic emulsifier, an anionic emulsifier, a reactive emulsifier, or the like can be used. Specific examples of the nonionic emulsifier include, for example, an alkyl ester of a polyethylene glycol or a polyalkylene glycol, a fatty acid ester, a sorbitan fatty acid ester, a sorbitan fatty acid ester, Examples of the anionic emulsifier include an alkali metal salt of rosin acid such as potassium rosinate or sodium rosinate; potassium oleate, potassium laurate, sodium laurate, sodium stearate, and the like. A sodium salt or a potassium salt of a fatty acid such as potassium stearate; a sulfate salt of an aliphatic alcohol such as sodium lauryl sulfate; an alkylarylsulfonate such as sodium dodecylbenzenesulfonate; and the like. Examples of the reactive emulsifier include, for example, Latemul S-180A (manufactured by Kao Corporation); Eleminol JS-2 (manufactured by Sanyo Chemical Industries Co., Ltd.); AQUALON KH-10 (first industry) Manufactured by Pharmaceutical Co., Ltd.; ADEKA REASOAP SE-10N, SR-10N (above manufactured by ADEKA); Antox MS-60 (manufactured by Nippon Emulsifier Co., Ltd.); Surfmer FP-120 ( Dongbang Chemical Industry Co., Ltd.) and so on.

The content ratio of the (B) surfactant in the hard coating agent used in the present invention is preferably 0.01 parts by mass to 99% by mass based on 100 parts by mass of the (A) polyfunctional (meth) acrylate. More preferably, it is 0.1 part by mass to 50 parts by mass, further preferably 0.5 part by mass to 25 parts by mass, particularly preferably 1 part by mass to 25 parts by mass, most preferably 3 parts by mass to 25 parts by mass. .

(B) The ratio of the compound represented by the formula (1) in the surfactant is preferably 20% by mass or more, and more preferably 50% by mass based on the total amount of the (B) surfactant. the above.

The content ratio of the (B) surfactant in the present specification is a value calculated based on the amount of the active ingredient when the surfactant is supplied in the form of a solution or a suspension.

[arbitrary ingredients]

The hard coat agent used in the present invention is preferably prepared by dissolving and dispersing the (A) polyfunctional (meth) acrylate and the (B) surfactant as described above in the (C) aqueous medium described later. The aqueous solution or aqueous dispersion obtained may contain any components other than those described above.

Here, examples of the other component to be used arbitrarily include (A) a polymerizable monomer component other than the polyfunctional (meth) acrylate, (D) a polyester, (E) a crosslinking agent, and (F) polymerization. Starting materials, organic particles, inorganic oxide particles, leveling agents, antifoaming agents, preservatives, antioxidants, thickeners, plasticizers, ultraviolet absorbers, pigments, and the like.

The hard coating agent used in the present invention may contain at least one selected from the group consisting of (D) polyester, (E) crosslinking agent, (F) polymerization initiator, and inorganic oxide particles. About hard coating agent The preferred content ratio of the (D) polyester, the (E) crosslinking agent, the (F) polymerization initiator, and the inorganic oxide particles will be described later.

The hard coat agent used in the present invention is characterized in that it does not need to contain a (meth)acrylic resin or a water-soluble polymer (polyethylene) which is generally used as a binder component or a dispersant in a known aqueous coating agent. Alcohol, etc.). In the case where the hard coat agent does not substantially contain a polymer component, the hardness of the formed hard coat layer becomes higher and more preferable. Here, the "polymer component" means a high molecular weight body having a polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography of about 10,000 or more.

-(D) Polyester -

(D) The polyester is a component having a function of improving the adhesion between the formed hard coat layer and the substrate.

The (D) polyester in the present invention can be obtained, for example, by a condensation reaction of a polybasic acid and a polyhydric alcohol.

Examples of the polybasic acid include phthalic acid, isophthalic acid, terephthalic acid, adipic acid, succinic acid, and the like; and examples of the polyhydric alcohol include ethylene glycol, propylene glycol, and 1,3-butylene glycol. 1,6-hexanediol, polyethylene glycol, polypropylene glycol, and the like.

With respect to the (D) polyester, the polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography may be, for example, 3,000 to 500,000, preferably 5,000 to 100,000.

The (D) polyester preferably has a small amount of a carboxyl group. By making (D) poly The ester has a carboxyl group, and a crosslinked structure can be formed by the (E) crosslinking agent, and a film having more excellent adhesion can be obtained, which is preferable. The content ratio of the carboxyl group in the (D) polyester can be represented by an acid value, and is, for example, 1 KOHmg/g to 30 KOHmg/g.

As a commercial item of the (D) polyester which can be used suitably in this invention, KA-5071S, KZT-8803, KT-8701, and KZT-9204 (The ;VYLONAL MD1200, MD1245, MD1480, MD1930, MD2000 (above manufactured by Toyobo Co., Ltd.); High-Tech PE series (such as PES-H001, manufactured by Toho Chemical Industry Co., Ltd.); Newtrack 2010 (made by Kao Co., Ltd.) ), Superflex 210 (manufactured by First Industrial Pharmaceutical Co., Ltd.), and the like.

The (D) polyester in the hard coating agent used in the present invention is preferably used insofar as it does not impair the hardness of the formed hard coat layer. The content ratio thereof is preferably 15 parts by mass or less, more preferably 0.1 parts by mass to 10 parts by mass, per 100 parts by mass of the (A) polyfunctional (meth) acrylate.

The (D) polyester is preferably a preparation of an aqueous hard coating agent which is supplied to the present invention as an aqueous solution or an aqueous dispersion (suspension). The content ratio of the (D) polyester in the present specification is a value calculated by using the amount of the active ingredient as a reference when the polyester is supplied in the form of a solution or a suspension.

- (E) crosslinker -

The (E) crosslinking agent is a component having a function of crosslinking the hard coating agent in the case where the (D) polyester is contained.

The (E) crosslinking agent in the present invention preferably has a reaction with a carboxyl group to form a bond. The part of the base. Examples of such a site include a site containing an amine group (especially a melamine-based amine group), an oxazoline, a carbodiimide, an epoxy group, an isocyanate or the like. The (E) crosslinking agent may be a low molecular weight compound or a high molecular weight body.

Commercial products of the (E) crosslinking agent which can be preferably used in the present invention are, for example, EPOCROS WS-500, WS-700, K-2000 (above manufactured by Nippon Shokubai Co., Ltd.); CARBODILITE V- 02, SV-02, V-02-L2, V-04, E-01, E-02 (above manufactured by Nisshinbo Chemical Co., Ltd.); NIKALAC MW-30M, MW-30, MW-11, MX-035 MX-45, BX-4000 (manufactured by Sanwa Chemical Co., Ltd.); ELASTRON series (for example, H-3, MF-9, etc., manufactured by Daiichi Kogyo Co., Ltd.) and the like.

The content ratio of the (E) crosslinking agent in the hard coating agent used in the present invention is preferably 10 parts by mass or less based on 100 parts by mass of the (A) polyfunctional (meth) acrylate. Preferably, it is 0.1 part by mass to 5 parts by mass. (E) The content ratio of the crosslinking agent is a value calculated based on the amount of the active ingredient when the crosslinking agent is supplied in the form of a solution or a suspension.

- (F) polymerization initiator -

(F) The polymerization initiator is a component which produces an active material which initiates polymerization of (A) a polyfunctional (meth) acrylate by light irradiation or heating. The (A) polyfunctional (meth) acrylate used in the present invention preferably can be spontaneously initiated by heating only by heating, so that even if the hard coating agent does not contain (F) a polymerization initiator High quality A hard coat layer, but may optionally contain (F) a polymerization initiator.

The (F) polymerization initiator may be water-soluble or oil-soluble.

Specific examples of the (F) polymerization initiator are as follows, for example.

The (F) polymerization initiator which generates an active material by light irradiation may, for example, be acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1 ,2-diphenylethane-1-one, xanthone, anthrone, benzaldehyde, anthraquinone, anthracene, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorodiphenyl Ketone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzoin dimethyl ketal, 1-(4 -isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylsulfide Xanthone, 2-isopropylthioxanthone, 2-chlorothiazepinone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1 -ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1,4-(2-hydroxyethoxy)phenyl-(2-hydroxyl -2-propyl) ketone, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzylidene)-2,4,4- Trimethylpentylphosphine oxide, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)acetone), and the like. Examples of such commercially available products include Irgacure 127, 184, 369, 379, 651, 500, 819, 907, 784, 2959, OXE01, OXE02, CGI1700, CGI1750, and CGI1850 manufactured by BASF Japan Co., Ltd. CG24-61, Darocur 1116, 1173, Lucirin TPO, 8893; Ubecryl P36 manufactured by UCB; Esacure KIP150, KIP65LT, KIP100F, KT37, KT55, KTO46, KIP75/B manufactured by Fratelli Lamberti.

(F) a polymerization initiator which generates an active material by heating, for example, can be listed Examples of organic peroxides such as hydrogen peroxides, peroxyesters, dialkyl peroxides, dioxonium peroxides, peroxydicarbonates, peroxyketals, and ketone peroxides; Persulfate such as ammonium, sodium persulfate or potassium persulfate; azo compound such as azobisisobutyronitrile or the like.

The content ratio of the (F) polymerization initiator in the hard coating agent used in the present invention is preferably 20 parts by mass or less based on 100 parts by mass of the (A) polyfunctional (meth) acrylate. More preferably, it is 10 parts by mass or less. By using 100 parts by mass of the (A) polyfunctional (meth) acrylate, preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more of the (F) polymerization initiator, It can effectively exhibit its beneficial effects.

-Inorganic oxide particles -

The hard coating agent used in the present invention may contain inorganic oxide particles for the purpose of further improving the storage stability of the hard coating agent and the hardness of the obtained hard coat layer.

The inorganic oxide particles are, for example, at least one selected from the group consisting of cerium oxide, aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, cerium oxide, indium oxide, tin oxide, cerium oxide, and cerium oxide. It is preferable that the particles are at least one oxide selected from the group consisting of cerium oxide, aluminum oxide, zirconium oxide, and titanium oxide as a main component. These may also be surface-treated by a compound having an alkoxy group, a carboxyl group, a (meth) acrylonitrile group, an epoxy group or the like.

The average particle diameter of the inorganic oxide particles is preferably from 1 nm to 2,000 nm, more preferably from 5 nm to 500 nm.

Content ratio of inorganic oxide particles in the hard coating agent used in the present invention In the case of 100 parts by mass of the (A) polyfunctional (meth) acrylate, it is preferably 1,000 parts by mass or less, more preferably 400 parts by mass or less. It is effective to express the inorganic oxide particles in an amount of preferably 1 part by mass or more, more preferably 10 parts by mass or more, based on 100 parts by mass of the (A) polyfunctional (meth) acrylate. Out of its beneficial effects.

- Leveling agent -

The leveling agent in the hard coating agent used in the present invention is used for the purpose of preventing shrinkage when the hard coating agent is applied and improving the uniformity of the formed coating film. The surfactant (B) is different in function from the above.

Such a leveling agent may, for example, be a polyorganosiloxane oxide leveling agent, a fluorine-based leveling agent, an acrylic polymer-based leveling agent or the like.

Commercially available products which can be suitably used as the leveling agent in the present invention include, for example, Polyflow KL-401, KL-402, KL-403, and KL-404 (the above is manufactured by Kyoeisha Co., Ltd.); BYK -302, BYK-307, BYK-325, BYK-331, BYK-333, BYK348, BYK378, BYK-UV-3535, BYK-UV-3530, BYK-UV-3500, BYK-381, BYK-3441 (above) Manufactured from BYK-CHEMIE JAPAN Co., Ltd.; DAW CORNING TORAY 8019ADDITIVE, DOW CORNING TORAY 1313 ANTIFORM EMULSION (manufactured by Toray Dow Corning Co., Ltd.), etc., one type selected from the above The above, or used after condensation.

The content ratio of the leveling agent in the hard coating agent used in the present invention is preferably 0.01 parts by mass to 10 parts by mass, based on 100 parts by mass of the (A) polyfunctional (meth) acrylate. Preferably, it is 0.01 parts by mass to 5 parts by mass.

- polymerization inhibition material -

The polymerization inhibiting material in the hard coating agent used in the present invention is used for the purpose of improving the storage stability of the hard coating agent.

Commercially available products which can be suitably used as such a polymerization inhibiting material are, for example, p-methoxyphenol, phenothiazine, BHT (manufactured by Wako Pure Chemical Industries, Ltd.), IRGANOX 1010, IRGANOX 1035 (above manufactured by BASF), and Sumilizer GA- 80 or more (manufactured by Sumitomo Chemical Co., Ltd.), Quino Power QS-30, and Quino Power QS-W10 (manufactured by Kawasaki Kasei Co., Ltd.) may be used, and one or more selected from the group may be used.

The content ratio of the polymerization inhibiting material in the hard coating agent used in the present invention is preferably 1 part by weight or less based on 100 parts by weight of the (A) polyfunctional (meth) acrylate, and more preferably 0.5 parts by weight or less.

[(C) Aqueous medium]

The aqueous medium contained in the hard coating agent used in the present invention is a medium containing only water, or a medium containing a mixture of water and a water-soluble organic medium.

The water-soluble organic medium is not particularly limited as long as it is an organic medium which is soluble in water, and examples thereof include alcohols and ethers. Specific examples of the water-soluble organic medium include methanol, ethanol, n-propanol, isopropanol, n-butanol, second butanol, third butanol, isobutanol, and n-hexanol. Examples include n-octanol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, and diacetone alcohol; and examples of the ethers include ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether.

When a mixture of water and a water-soluble organic medium is used as the (C) aqueous medium, the use ratio of the water-soluble organic medium is preferably 10% by mass or less based on the total amount of the (C) aqueous medium. As the (C) aqueous medium in the present invention, it is preferred to use only water. Moreover, it is preferred that the hard coating agent in the present invention does not contain a medium other than the (C) aqueous medium.

[hard coating agent]

The hard coating agent containing the above components can be prepared by dispersing and mixing the above components by a known method.

The hard coating agent preferably contains at least (A) a polyfunctional (meth) acrylate and, in the case of use, (D) a polyester, (E) a crosslinking agent, (F) a polymerization initiator. An oil droplet is an emulsion in a state of being emulsified and dispersed in (C) an aqueous medium by the action of (B) a surfactant. The oil droplets preferably have a volume average particle diameter of 10 nm to 3 μm, more preferably 50 nm to 2 μm, still more preferably 100 nm to 1,500 nm, and particularly preferably 200 nm to 1,200 nm. By dispersing the oil droplets in the particle diameter of this range, the hard coating agent is excellent in storage stability, and exhibits good coatability, and a hard coat layer having a high hardness uniformity can be formed, which is preferable.

As the viscosity of the hard coating agent, the viscosity measured by the E-type viscometer at 25 ° C is preferably 1 mPa. s~200mPa. s, more preferably 1.5mPa. s~100mPa. s.

<Method for Producing Hard Coating Film>

The method for producing a hard coat film of the present invention is characterized in that the aqueous hard coat agent is applied in-line on at least one side of the thermoplastic resin film. Here, the term "in-line coating" refers to a coating step performed in the production step of the film or a coating step which is continuously performed after the film production step. In the present invention, it is preferred to carry out in-line coating in the production step of the film.

The method for producing a hard coat film of the present invention is a method of applying the aqueous hard coat agent (coating step) on a sheet-like resin at an arbitrary timing of the production of the stretched film; the production of the stretched film is

Forming a thermoplastic resin into a sheet shape (forming step) to make the sheet-like resin

Extending in the longitudinal direction (longitudinal direction) (first extension step), and further extending in the short side direction (width direction) (second extension step), preferably further thereafter

A heat treatment step is performed.

Hereinafter, each step of the method for producing a hard coat film of the present invention will be described in order.

[Molding step]

First, a preferred particulate thermoplastic resin is preferably sufficiently dried and then formed into a sheet shape by using a suitable molding apparatus. Examples of the method of forming the thermoplastic resin into a sheet form include a melt extrusion method, a melt casting method, a calender method, and the like. Among these, a melt extrusion method is preferred, and examples of the apparatus used in the melt extrusion method include a single screw extruder, a twin screw extruder, and the like.

The thermoplastic resin is melt extruded using the forming device, preferably The unstretched resin sheet was produced by cooling and solidification by an electrostatic application method. The sheet may be a single layer or a plurality of layers. The melting temperature is, for example, 200 ° C to 300 ° C, and the cooling temperature is, for example, 0 ° C to 50 ° C.

[1st extension step]

The obtained unstretched resin sheet was subjected to uniaxial stretching extending in the longitudinal direction (traveling direction).

The extension in the longitudinal direction can be carried out, for example, by heating a roller having a temperature of from 80 ° C to 120 ° C, preferably from about 80 ° C to 100 ° C. The stretching ratio in the traveling direction is preferably about 2 to 5 times to obtain a stretched film.

[2nd extension step]

Next, the coated film is subjected to a second stretching step extending in the short-side direction.

The extension in the short-side direction can be performed by holding an end portion of the film extending in the longitudinal direction by an appropriate method such as fixing by a jig, and extending to the hot air region. The temperature in the hot air region is, for example, 70 ° C to 140 ° C, preferably 80 ° C to 120 ° C. The stretching ratio in the short side direction is preferably 2.5 times to 5 times.

[heat treatment step]

It is more preferable to carry out the heat treatment step for the film which has passed through the second stretching step. The crystallization alignment of the film is promoted by the arbitrary heat treatment step to be completed.

The heat treatment can be carried out by, for example, adjusting the temperature of the film after the second stretching to a heat treatment zone of, for example, about 160 ° C to 240 ° C for, for example, 1 second to 60 seconds. In the domain.

[Coating step]

The aqueous hard coating agent is applied (in-line coating) at any time point in the production step of the stretched film as described above.

A suitable method can be employed for the coating method. Specific examples thereof include a gravure coating method, a die coating method, a spray coating method, a bar coating method, a reverse roll coating method, a curtain coating method, a dip coating method, and the like.

Preferably, the coating step is performed at any time before the first stretching step, after the first stretching step, before the second stretching step, and after the second stretching step, after the resin is formed into a sheet shape, more preferably It is performed after the first extension step and before the second extension step.

The hard coat film can be obtained as described above.

The thickness of the coating film in the final hard coat film is preferably from 0.1 μm to 30 μm, more preferably from 1 μm to 15 μm.

The thickness of the hard coat film obtained by the above method can be suitably set, and the total thickness of the final hard coat film can be, for example, in the range of 10 μm to 500 μm, particularly 20 μm to 300 μm.

In the case where the hard coat film of the present invention is produced by a process accompanying elongation, the thickness of the coating film and the total thickness of the film are both extended values.

<hard coating film>

The hard coat film obtained by the method for producing a hard coat layer of the present invention as described above contains a hard coat layer on at least one side. The pencil hardness of the surface is usually HB or more, preferably F or more, more preferably 2H or more, and particularly preferably 3H or more. Further, the scratch resistance (steel resistance test) of the surface is preferably such that no damage occurs under the condition of a load of 200 kg/cm ² , and more preferably, it is not produced under the condition of a load of 300 kg/cm ² . Scars.

[Examples]

<General experimental method>

In the following examples and comparative examples, a polyethylene terephthalate (PET) film was used as a substrate film, and various hard coating agents were applied to one side of the film by an in-line process and thermally hardened. A hard coat layer was formed and evaluated.

The general experimental method is as follows.

The PET pellets (homopolymer) were sufficiently dried, and then supplied to a uniaxial extruder, melted at 250 ° C, and extruded from a T-die into a sheet shape, and then wound at 45 ° C by an electrostatic application casting method. On the cooling roll, cooling and solidification were carried out, whereby an unstretched film of PET was obtained.

The unstretched film was heated to 90 ° C and stretched 3.0 times in the longitudinal direction to prepare a uniaxially stretched film.

The hard coating agents prepared in the respective Examples and Comparative Examples were applied to one side of the film by a reverse roll coating method. The film coated with the hard coating agent was guided to a preheating zone and heated and dried at 130 ° C for 1 minute, and then extended by 3.0 times in the short side direction at 90 ° C (the total elongation was 3.0 times in the longitudinal direction). , the direction of the short side is 3.0 times). Next, the film was further guided to a thermosetting region and heated at 230 ° C for 30 seconds. The coating film was thermally hardened, whereby a hard coat film containing a hard coat layer having a thickness of 2.0 μm on one surface of a substrate film having a thickness of 188 μm was obtained.

Further, in the case where a photopolymerization initiator is used as the (F) polymerization initiator, the high pressure mercury lamp is used at 3,000 J/m before the film after the application of the hard coating agent is introduced into the thermosetting region. The irradiation amount of ² is irradiated with ultraviolet rays.

The following evaluation was performed about this hard coat film.

(1) Evaluation of coating appearance

The hard coat layer formed shortly after the observation was visually observed and evaluated by the following criteria.

Smooth surface and no whitening found: excellent coating appearance

The surface condition is slightly thicker or slightly whitened: the coating looks good

Poor surface condition: poor coating appearance

(2) Evaluation of pencil hardness

Regarding the hard coat forming surface of the obtained hard coat film, the pencil hardness was measured in accordance with JIS K 5600-5-4. In the application assumed in the present invention, when the pencil hardness is H or more, the hardness of the hard coat film is high, and when it is 2H or more, the hardness of the hard coat film is sufficiently high.

(3) Scratch resistance (steel resistance test)

Steel wool (Bonstar No. 0000, manufactured by Nippon Steel Wool Co., Ltd.) was attached to a vibration-type friction fastness tester ("AB-301", manufactured by TESTER SANGYO Co., Ltd.). The surface of the cured film was rubbed 10 times under the conditions of 300 g/cm ² , and the presence or absence of scratches on the surface of the film after the rubbing was visually confirmed, and the evaluation was performed according to the following evaluation criteria.

No damage (no injury) on the cured film: excellent

Produces several scratches on the cured film: good

Many scratches or hardened film peeling on the cured film: bad

Embodiment 1 to Embodiment 14

As a hard coating agent, the components and amounts of the components described in Table 1 were mixed with water, and dispersed and mixed using an ultrasonic disperser under ice cooling to prepare an aqueous dispersion having a solid concentration of 25% by mass. Further, in addition to the above, a hard coat layer was formed in the order of the "general experimental method", and various evaluations were performed.

The evaluation results are shown together in Table 1.

Comparative Example 1 to Comparative Example 4

A hard coat layer was formed in the order of the "general experimental method" except that the coating agent was used as described in Table 1, and various evaluations were performed.

The evaluation results are shown in Table 2.

In Tables 1 and 2, the abbreviations of the hard coating agent or its components are respectively the following meanings.

[Component of hard coating agent of the example]

-polyester-

PE1: a polyester resin emulsion (glass transition temperature = 66 ° C, number average molecular weight = 8,000) manufactured by Uniji Co., Ltd. under the trade name "KA5071S", and a solid content concentration = 30% by mass, as described in Table 1, The amount used is the amount of active ingredient.

PE2: The product name "VYLONAL MD1245", the water-dispersed polyester resin manufactured by Toyobo Co., Ltd., the solid content concentration = 34% by mass, and the usage amount described in Table 1 is the amount of the active ingredient.

-crosslinker -

A water-soluble polymer containing an oxazoline group: trade name "EPOCROS WS-500", manufactured by Nippon Shokubai Co., Ltd., solid content concentration = 35 mass%, and the use amount described in Table 1 is an active ingredient amount.

Methylated melamine resin: trade name "MW-30M", Sanhe Chemical Co., Ltd. Limited company manufacturing.

Carbonodiimide: Trade name "V-02", manufactured by Nisshinbo Chemical Co., Ltd., solid content concentration = 40% by mass, and the amount used in Table 1 is the amount of the active ingredient.

-other-

SF1: Anionic surfactant prepared by Japan Emulsifier Co., Ltd., product name "Newcol 707SF", aqueous solution having a solid concentration of 10% by mass, and active ingredient polyoxyalkylene polycyclic phenyl ether. Sulfate. The ammonium salt and the amount used in Table 1 are the amount of the active ingredient.

CSi: Colloidal cerium oxide having a volume average particle diameter of 35 nm modified by 3-methyl propylene oxypropyltrimethoxy decane by a colloidal cerium oxide dispersion manufactured by Fuso Chemical Industry Co., Ltd. The aqueous dispersion having a solid content concentration of 20% by mass and the amount used in Table 1 are the amount of the active ingredient.

CZr: particle size distribution (dynamic light scattering method) of zirconia dispersion prepared by 堺Chemical Industries Co., Ltd. by 3-methyl propylene oxypropyltrimethoxy decane D50= A 5 nm zirconia dispersion, an aqueous dispersion having a solid concentration of 30%, and an amount used in Table 1 are effective component amounts.

Anthrone compound: trade name "8019ADDITIVE", polyether modified anthrone manufactured by Toray Dow Corning Co., Ltd.

Polymerization inhibiting material: p-methoxyphenol manufactured by Wako Pure Chemical Co., Ltd.

[Coating agent of Comparative Example]

In the comparative examples, the following were directly used as a coating agent by the concentrations described below.

Acrylic emulsion: an acrylic emulsion manufactured by E-TEC Co., Ltd., product name "AE373D", and an emulsion having a solid concentration of 50% by mass.

SiO: a decane resin manufactured by Shin-Etsu Chemical Co., Ltd., which was diluted with a product name "KR-500" (alkoxy oligomer) to a solid concentration of 30% by mass with propylene glycol monomethyl ether acetate .

coP1: A diluted solution of the copolymer solution obtained as shown in Comparative Synthesis Example 1 below.

Acrylic urethane: Acrylic urethane oligomer/peroxide initiator prepared according to Experimental Example 1 of Patent Document 5 (Japanese Patent Laid-Open Publication No. 2008-524402) / Melamine crosslinker is a hardening composition.

Comparative Synthesis Example 1

5 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) and 200 parts by mass of diethylene glycol ethyl methyl ether were placed in a flask equipped with a condenser and a stirrer. Then, 25 parts by mass of styrene, 20 parts by mass of methacrylic acid, 45 parts by mass of glycidyl methacrylate, and 10 parts by mass of tricyclo [5.2.1.0 ^2,6 ]decane-8-yl methacrylate were added. After the nitrogen exchange, the stirring was started slowly. The temperature of the solution was raised to 70 ° C, and the temperature was maintained for 5 hours to carry out polymerization, whereby a polymer solution containing a copolymer was obtained.

The solid content concentration of the obtained polymer solution was 33.0% by mass. The copolymer contained in the copolymer solution had a polystyrene-equivalent weight average molecular weight (Mw) of 4,000.

To the obtained polymer solution, propylene glycol monomethyl ether acetate will be added A diluted solution having a solid content concentration adjusted to 15% by mass was used as a coating agent (coP1).

Claims (10)

A method for producing a hard coat film, which is a method for producing a hard coat film comprising a hard coat layer on at least one side of a thermoplastic resin film, characterized in that it is applied in-line on at least one side of the thermoplastic resin film The step of an aqueous hard coating agent. The method for producing a hard coat film according to the first aspect of the invention, wherein the in-line coating is performed after extending the unstretched thermoplastic resin film in the longitudinal direction and extending in the width direction. The method for producing a hard coat film according to claim 1, wherein the aqueous hard coat agent comprises: (A) a polyfunctional (meth) acrylate, (B) a surfactant, and (C) Aqueous medium. The method for producing a hard coat film according to claim 3, wherein the (A) polyfunctional (meth) acrylate is a (meth) acrylate of an aliphatic polyol or a dimer thereof, Further, it is a polyfunctional (meth) acrylate compound having two or more (meth) acrylonitrile groups in the molecule. The method for producing a hard coat film according to claim 3, wherein the (B) surfactant comprises a compound represented by the following formula (1): XO-(R ¹ O) _n -R ² (1) (In the formula (1), X is a group having an aromatic ring, R ¹ is an alkylene group having 2 to 4 carbon atoms, and R ² is a hydrogen atom, PO(OM) ₂ or SO ₃ M ( Wherein M is a hydrogen atom, an ammonium ion or a metal ion), and n is an integer of 5 to 150). The method for producing a hard coat film according to claim 3, wherein the aqueous hard coat agent further comprises (D) a polyester. The method for producing a hard coat film according to claim 3, wherein the aqueous hard coat agent further comprises (E) a crosslinking agent. The method for producing a hard coat film according to any one of claims 1 to 7, wherein the aqueous hard coat agent is dispersed in (C) an aqueous medium and contains at least (A) polyfunctional An emulsion of oil droplets of (meth) acrylate. The method for producing a hard coat film according to any one of claims 1 to 7, wherein the aqueous hard coat agent further contains (F) a polymerization initiator. The method for producing a hard coat film according to any one of claims 1 to 7, wherein the thermoplastic resin film is selected from the group consisting of polyethylene terephthalate and polytrimethylene terephthalate. A polyester film of a diester, polybutylene terephthalate, polyethylene naphthalate, and poly(naphthalene dicarboxylate).