JP2011183560A - In-mold transfer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that when a base material provided with an UV cured hard coat coating film is machined, since the coating film cannot follow the stress by the machining, a crack and the like are caused, the interruption of the curing of the UV curing type hard coat on the way to improve machinability of the coating film is difficult since the UV curing is finished in a short period of time and the molding by the in-mold transfer has the same difficulty. <P>SOLUTION: The in-mold transfer film is capable of carrying out two-stage curing by adopting a resin having a specific structure as a coating material for the UV curing type hard coat coating film and then, an in-mold transfer foil is formed using a coating material composition for hard coat having excellent machinability. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an in-mold transfer film for hard coat.

  The casings of notebook computers and mobile phones are mainly manufactured by plastic injection molding. Since the surface of the plastic casing is easily damaged, a hard coating for preventing damage is indispensable as a candle for enhancing design. Therefore, various UV curable resins are generally employed as the hard coating agent.

  In forming the hard coat layer, first, the transfer foil is manufactured by applying this UV curable resin via a release layer provided in advance on the base film for the transfer foil. Since the hard coat layer of the cured transfer foil has high hardness in in-mold transfer during plastic injection molding, it has a low elongation rate and cannot follow the shape to be obtained by injection molding. The hard coat layer was cut and cracked, and the yield deteriorated.

  For this purpose, the amount of UV irradiation required for curing the UV curable hard coat layer during transfer foil production is reduced, and a relatively flexible film is formed by suppressing the UV radical polymerization reaction before complete curing. There is a method of obtaining the necessary surface hardness by completing UV polymerization again after transfer molding on the surface of the surface to complete the radical polymerization reaction.

However, since the UV radical polymerization reaction is completed at the moment of UV irradiation, advanced technology is required to control and suppress the reaction before complete curing, and this method eventually produces products of uniform quality. It was difficult to do.
And it is known to examine the method of obtaining a transfer foil by curing urethane (meth) acrylate and hard coat layer with ionizing radiation (Patent Documents 1 to 3).

  Also, for resin molded products in which a hard coat layer is provided on the resin, if the hard coat layer is hard and has a low elongation rate and a scratch-resistant hard coat layer, the shape of the product is changed by bending the resin molded product, Such a resin molded product could not be provided with a hard coat layer because it could not follow the change in shape and cracked.

JP 2006-0662206 A JP 2007-118465 A JP 2008-006708 A

As described above, when photocuring the UV curable hard coat layer, the curing is instantaneously completed. Therefore, the curing is interrupted in the middle, and the hardness suitable for the subsequent processing of the coating film. In order to obtain this coating film, it took time and effort to control the irradiation of light fairly carefully.
Further, when a process that applies stress to the coating film, such as processing the base material of the coating film after forming the hard coat coating film, inconveniences such as cracks in the hard coat coating film have occurred.
For this reason, since it was difficult to set the hardness in the middle for the purpose of smoothly bending the base material of the sheet such as the transfer foil on which the coating film was formed, it was optional during the curing. It was necessary to set the hardness so that the above-described processing could be performed.

In order to solve the above problems, the present invention contains a compound obtained by reacting a polyvalent isocyanate compound with a vinyl group-containing monohydric alcohol or a vinyl group-containing monovalent amine, and the NCO equivalent of the polyvalent isocyanate compound before the reaction. An in-mold transfer film obtained by applying a coating composition having a smaller hydroxyl group and amine equivalent of the vinyl group-containing monohydric alcohol or vinyl group-containing monohydric amine on the film, followed by primary curing, The monovalent isocyanate compound may be tolylene diisocyanate, a vinyl group-containing monohydric alcohol, and the amine may be a monohydric alcohol or monohydric amine containing an acryloyl group, or may contain a ketone solvent.
Furthermore, the coating film formed by applying such a coating composition and performing primary curing or secondary curing. A transfer foil obtained by applying the coating composition on a substrate and primary-curing, a transfer method of transferring the transfer foil to an article and secondary-curing, and an obtained article.

  According to the present invention, an in-mold transfer film for forming a hard coat layer does not require an uncontrollable UV radical reaction, and an elongation rate that follows the shape of a plastic product by a heat polymerization reaction that is easy to control. A cured film having a large thickness can be formed. When the obtained in-mold transfer film is used, a UV radical reaction is caused by UV irradiation after molding, and a hard coat film by in-mold transfer of uniform quality without defects such as cracks can be obtained with a high yield. it can.

  When producing a pre-coated metal plate such as aluminum or iron, the coating composition of the present invention is applied, and the coated layer is heated to obtain a flexible and workable pre-coated metal plate, which is then pressed or the like. By irradiating with UV or electron beam after being bent by, a processed product using a pre-coated metal plate having a hard coat layer having no scratch on the surface and having excellent scratch resistance on the surface can be provided.

式２

（上記式中、Ｒ_１及びＲ_２は共に炭化水素基） Hereinafter, the present invention will be described in detail.
As shown in the following formula 1, the coating composition in the present invention is a urethane compound obtained by reacting a polyvalent isocyanate compound with a vinyl group-containing alcohol having an OH equivalent smaller than the NCO equivalent of the polyvalent isocyanate compound, or As shown in Formula 2, it contains a urea compound obtained by reacting a vinyl group-containing amine having an amine equivalent smaller than the NCO equivalent of the polyvalent isocyanate compound.
Formula 1

Formula 2

(In the above formula, R ₁ and R ₂ are both hydrocarbon groups)

  This urethane compound or urea compound is a group having a urethane bond or urea bond formed by a reaction of an isocyanate group with a vinyl group-containing monohydric alcohol or vinyl group-containing monovalent amine, and a vinyl group-containing monohydric alcohol or vinyl group-containing 1. The polyvalent amine has an unreacted isocyanate residue, and the isocyanate residue is contained in a proportion of 10 to 30%, preferably 13 to 25%, more preferably 15 to 20% of the isocyanate group before the reaction. Also good.

The following formula 3 is shown as an example of the reaction of the urethane compound.
Formula 3

（式３及び４に記載のＲは炭化水素基を示す。また、上記Zはイソシアネート基が結合している残基一般を示し、Zを有する化合物はトリイソシアネート化合物に限定されない。） As an example of the reaction of the urea compound, the following formula 4 is shown.
Formula 4

(R in the formulas 3 and 4 represents a hydrocarbon group. Further, Z represents a general residue to which an isocyanate group is bonded, and a compound having Z is not limited to a triisocyanate compound.)

When such a coating composition is applied on a film and heated, as shown in the following formula 5, the urethane bond and isocyanate residue of the urethane compound react to form an allophanate bond by the primary curing reaction. Alternatively, as shown in the following formula 6, the urea bond and the isocyanate residue react to form a burette bond.
The primary cured coating film after the primary curing reaction is not completely cured, and the coating film has high elongation and strength, and has sufficient flexibility.

Formula 5

Equation 6

Reactions that form allophanate bonds or burette bonds as shown in formulas 5 and 6 may form allophanate bonds or burette bonds between two molecules as shown in these formulas, but between three or more molecules. These bonds may be formed.
The coating film that has undergone the primary curing reaction is used as an in-mold transfer film due to this property, and even if it is transferred to the surface of the resin molded body by in-mold molding, the coating film is not cracked or cracked. Therefore, a hard coat layer having a smooth surface and high hardness can be formed.

  Further, when the primary cured film transferred to the surface of the resin molded body is irradiated with energy rays such as UV or electron beam, the urethane compound or urea compound in the coating film has, as shown in the following formulas 7 and 8. Vinyl groups react and crosslink by radical polymerization. The resulting coating film loses sufficient flexibility and forms a hard coat layer that is extremely hard and excellent in scratch resistance.

  For this reason, a photopolymerization initiator, its auxiliary agent, a weather resistance stabilizer, an ultraviolet absorber, etc. can be added to the coating composition in the present invention, and in addition, a filler, thixotropic agent, storage stability. Known paint additives such as property improvers (dehydrating agents) and colorants can be added.

Equation 7

Equation 8

The coating composition in this invention is demonstrated concretely.
A. Paint composition
[Polyisocyanate compound]
The polyvalent isocyanate compound in the present invention is not particularly limited, and examples thereof include aromatic, aliphatic, and alicyclic polyisocyanates, among which isocyanurate, tolylene diisocyanate, and diphenylmethane. Diisocyanate, hydrogenated diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate , Norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, phenylene dii Polyisocyanates such as cyanate, biphenylene diisocyanate, cyclohexylene diisocyanate, lysine diisocyanate, lysine triisocyanate, naphthalene diisocyanate, or the like, trimer compounds or tetramer compounds of these polyisocyanates, or prepolymers can be used. It is a prepolymer of tolylene diisocyanate or hexamethylene diisocyanate in consideration of handling properties, low viscosity and low thixotropy. It is also possible to select and use a plurality of polyvalent isocyanate compounds.

[Vinyl group-containing alcohol]
The vinyl group-containing alcohol used in the present invention is a hydroxyl group-containing vinyl compound having a photocurable vinyl bond and a hydroxyl group in one molecule.
Among them, the vinyl group-containing monohydric alcohol is not particularly limited as long as it is an acrylic acid partial ester of a polyhydric alcohol, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2 -Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethylacryloyl phosphate, 6-hydroxyhexyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2 -Hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, 3-hydroxy-2-ethylhexyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, tetramethylol methane Acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, trihydroxyethyl isocyanurate di (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, Caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, and the like can be used. Of these, 2-hydroxyethyl (meth) acrylate and pentaerythritol tri (meth) acrylate are preferable.

Examples of vinyl group-containing polyhydric alcohols include tetramethylolmethane diacrylate, trimethylolpropane (meth) acrylate, glyceryl (meth) acrylate, pentaerythritol di (meth) acrylate, dipentaerythritol tetra (meth) acrylate, and trihydroxyethyl isocyanate. Nurate (meth) acrylate, caprolactone-modified dipentaerythritol tetra (meth) acrylate, caprolactone-modified pentaerythritol di (meth) acrylate, ethylene oxide-modified dipentaerythritol tetra (meth) acrylate, ethylene oxide-modified pentaerythritol di (meth) acrylate, etc. A compound obtained by esterifying one hydroxyl group of trivalent or higher alcohol with (meth) acrylic acid can be used.
Moreover, each said vinyl group containing alcohol may superpose | polymerize by the unsaturated bond.

[Vinyl group-containing amine]
Examples of the vinyl group-containing amine used in the present invention include vinylamines, 1-vinylmethylamine, 2-vinylethylamine, vinylalkylamines such as 3-vinylpropylamine, aminomethyl (meth) acrylate, and aminoethyl (meth) acrylate. A (meth) acrylic acid ester of an aminoalkyl alcohol such as aminopropyl (meth) acrylate can be used.

[Reaction conditions]
In order to synthesize a urethane compound or a urea compound by reacting a polyvalent isocyanate compound with a vinyl group-containing alcohol and / or a vinyl group-containing amine, conditions used for a known reaction between an isocyanate and an alcohol or an amine can be employed.

  In such a reaction, a metal catalyst such as tin carboxylate such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin bis-acetoacetonate, tin octoate or the like is used as a reaction catalyst for the purpose of further promoting the reaction. , Tetramethylbutanediamine, triethylenediamine, and amine-based catalysts such as 1,8-diazabicyclo [5.4.0] undecene-7 are also preferably used, and the reaction temperature is 30 to 90 ° C., particularly 40 to 40 ° C. A range of 70 ° C. is preferred.

  In the reaction, the catalyst component is added in an amount of 0.001 to 5.0% by weight, preferably 0.001 to 0.1% by weight, more preferably 0.005 to 0.05% by weight, based on the solid content of the product. Used in quantity.

  The solvent used in the reaction may be any solvent that is not reactive with isocyanate groups, such as hydrocarbons such as toluene, xylene, isooctane and hexane, ketones such as MEK, acetone, butanone and MIBK, ethyl acetate and acetic acid. Esters such as butyl, tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, dimethylformamide and the like can be used, and ketones are particularly preferable from the viewpoint of the stability of the coating composition. It is thought that the isocyanate group is stabilized by associating with the isocyanate group.

  The photopolymerization initiator is not particularly limited as long as it generates radicals by the action of light. For example, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, 1- (4-isopropylenephenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2- Methylpropan-1-one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholinopropane-1, benzoin, benzoin methyl ether, benzoin ethyl Ether, benzoyl isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl -4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, camphorquinone, dibenzosuberone, 2-ethylanthraquinone, 4 ' , 4 ″ -diethylisophthalophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, α-acyloxime ester, acylphosphine oxa Id, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, benzoyl peroxide, di-t-butyl peroxide Among them, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl- 1-phenylpropan-1-one, benzoyl peroxide, and di-t-butyl peroxide are preferably used.

  Further, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylamino as an auxiliary for the photopolymerization initiator Ethyl benzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthio It is also possible to use xanthone or the like together.

  The urethane compound in the present invention has, for example, the ratio of the equivalent of the polyvalent isocyanate compound to the hydroxyl group equivalent of the vinyl group-containing alcohol, the equivalent of the polyvalent isocyanate compound: the hydroxyl group equivalent of the vinyl group-containing alcohol = 1.02: 1-2. : 1, preferably 1.1: 1 to 1.3: 1, more preferably 1.13: 1 to 1.25: 1, and even more preferably 1.15: 1 to 1.2: 1. It can be obtained by mixing and reacting. The reaction is preferably performed at about 60 to 80 ° C. for about 5 to 12 hours. At that time, an organic solvent, a polymerization inhibitor such as hydroquinone monomethyl ether, or the like can be used as necessary. Examples of the organic solvent include organic solvents such as ester organic solvents such as ethyl acetate and butyl acetate, ketone organic solvents such as methyl ethyl ketone, and aromatic organic solvents such as toluene and xylene. These may be used alone or in combination of two or more.

  Similarly, the urea compound in the present invention has, for example, the ratio of the equivalent of the polyvalent isocyanate compound to the amine equivalent of the vinyl group-containing amine, the equivalent of the polyvalent isocyanate compound: amine equivalent of the vinyl group-containing amine = 1.02: 1 2: 1, preferably 1.1: 1 to 1.3: 1, more preferably 1.13: 1 to 1.25: 1, and even more preferably 1.15: 1 to 1.2: 1. Can be mixed and reacted to obtain.

  The weather resistance stabilizer is used to prevent oxidation, light deterioration, heat deterioration, etc. of the cured product, and to further improve not only the weather resistance but also the heat resistance, a hindered amine light stabilizer, a hindered Examples include phenolic antioxidants, UV absorbers, hindered amine light stabilizers alone, hindered phenolic antioxidants alone, or combinations of hindered amine light stabilizers and hindered phenolic antioxidants, that is, A hindered amine light stabilizer and / or a hindered phenol-based antioxidant is preferable in that the effect of improving weather resistance is high.

  Examples of hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-decanoate. Piperidyl) ester, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2, , 6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine and other low molecular weight light stabilizers having a molecular weight of less than 1000; dimethyl succinate, 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2, 4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], N, N ′ -Bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3 , 5-triazine compression In addition to the compound, a high-molecular weight light stabilizer having a molecular weight of 1000 or more such as a product of ADEKA, trade names Adeka tab LA-63P, LA-68LD and the like can be mentioned.

Hindered phenol antioxidants include pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl). -4-hydroxyphenyl) propionate], N, N'-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropioamide], benzenepropanoic acid 3,5- Bis (1,1-dimethylethyl) -4-hydroxy C ₇ -C ₉ side chain alkyl ester, 2,4-dimethyl-6- (1-methylpentadecyl) phenol and the like can be mentioned.

Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers such as 2- (3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (4,6-diphenyl-1, 3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol and other triazine ultraviolet absorbers, benzophenone ultraviolet absorbers such as octabenzone, 2,4-di-tert-butylphenyl- Examples thereof include benzoate ultraviolet absorbers such as 3,5-di-tert-butyl-4-hydroxybenzoate.
These can be used alone or in combination of two or more.

  The weather resistance stabilizer is preferably blended in an amount of 0.01 to 30 parts by weight, particularly 0.1 to 10 parts by weight, based on 100 parts by weight of the isocyanate group-containing urethane prepolymer.

  Fillers, thixotropic agents, adhesion improvers, storage stability improvers (dehydrating agents), and colorants reinforce and increase physical properties, prevent sagging (slump), improve adhesion, and improve storage stability. For coloring, etc., the hard coat coating composition used in the present invention can be blended and used.

  Fillers include mica, kaolin, zeolite, graphite, diatomaceous earth, white clay, clay, talc, slate powder, anhydrous silicic acid, quartz fine powder, aluminum powder, zinc powder, precipitated silica, synthetic silica, calcium carbonate, carbonic acid Inorganic powder fillers such as magnesium, alumina, calcium oxide, magnesium oxide; fibrous fillers such as glass fibers and carbon fibers; inorganic balloon fillers such as glass balloons, shirasu balloons, silica balloons, ceramic balloons, etc. Inorganic fillers; or fillers whose surfaces are treated with organic substances such as fatty acids; wood flour, walnut flour, rice husk flour, pulp flour, cotton chips, rubber powder, thermoplastic or thermosetting resin fine powder, Organic powder fillers such as polyethylene powder; polyethylene hollow bodies, saran microphones In addition to organic fillers such as balloon balloons and other organic balloon fillers, examples include flame retardant fillers such as magnesium hydroxide and aluminum hydroxide, and particles having a particle size of 0.01 to 1,000 μm. Is preferred.

  Examples of the thixotropic agent include inorganic thixotropic agents such as colloidal silica and fatty acid-treated calcium carbonate, and organic thixotropic agents such as organic bentonite and fatty acid amide.

  Examples of the adhesion improver include a coupling agent, and examples of the coupling agent include various coupling agents such as silane-based, aluminum-based, and zircoaluminate-based compounds or partial hydrolysis condensates thereof. Of these, a silane coupling agent or a partially hydrolyzed condensate thereof is preferable because of its excellent adhesiveness.

  Specific examples of the silane coupling agent include vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane. Methoxysilane, vinylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane , 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and other alkoxysilyl group-containing molecular weights of 500 or less, preferably 400 or less, or these silane coupling agents It may include compounds having a molecular weight of 200 to 3,000 with one or more partially hydrolyzed condensate. These can be used alone or in combination of two or more.

Examples of the storage stability improver include vinyltrimethoxysilane, calcium oxide, p-toluenesulfonyl isocyanate and the like that react with moisture present in the composition.
In addition, p-toluenesulfonyl isocyanate is particularly preferable because it also serves as a curing accelerator when a compound that reacts with moisture to generate an active hydrogen-containing functional group is used.

Examples of the colorant include inorganic pigments such as titanium oxide and iron oxide, organic pigments such as copper phthalocyanine, and carbon black.
These can be used alone or in admixture of two or more.

  The total blending amount of the filler, thixotropic agent, adhesion improver, storage stability improver, and colorant is 0 to 500 parts by weight, particularly 5 to 100 parts by weight of the isocyanate group-containing urethane prepolymer. It is preferable that it is 300 mass parts.

  In the coating composition of the present invention, each of the additives can be used alone or in combination of two or more.

B. Method for forming a cured coating film using a coating composition
[Method for forming coating film]
Means for forming a coating film on a film using the coating composition in the present invention is a known coating apparatus such as spray, dipping, fountain coater, flow coater, curtain coater, roll coater, bar coater, gravure coater, blade coater, etc. Or a printing device can be used. Moreover, after apply | coating on another film and obtaining a coating film once, the formation method of the coating film by transferring the coating film is also employable.

The material of the object on which the coating film is formed is not limited as long as it is a film that can be a base film of an in-mold transfer film, and known substances such as paper, cloth, wood sheets, various synthetic resins, and the like are combined. It will not be limited.
However, a coating composition that is supplied as an in-mold transfer film into a mold, is deformed by being sandwiched between the molds, and does not change even when heated by supplying molten resin into the mold and is primarily cured. It is necessary that the base film be easy to peel off from the coating film which has been subjected to primary curing or secondary curing after molding, following the elongation of the coating film.

Furthermore, the resin molded body transferred by the in-mold transfer film should be widely used for publicly known applications such as buildings, ships / aircrafts, automobiles and other transportation equipment, electrical products, machines, devices, ornaments, containers, etc. Can do.
Among these materials and applications, applications that require the formation of a hard coat layer are preferred.

  The film in the present invention may be a film in which a base film and a release layer are sequentially laminated, and a printing ink layer and / or a heat seal layer may be provided on the laminated coating composition layer in the present invention. . Depending on the resin to be molded, it may be inferior in adhesion to the primary or secondary cured coating composition. In such a case, by providing a printing ink layer and / or a heat seal layer and a primer layer in particular. It is necessary to improve the adhesion.

Examples of the film to which the coating composition of the present invention is applied include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as nylon 6, polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, and polyvinyl chloride. Examples thereof include vinyl resins, (meth) acrylic resins such as polymethyl methacrylate, cellulose films such as polycarbonate, cellophane, and cellulose acetate. In view of heat resistance and mechanical strength, a polyester film such as polyethylene terephthalate or polyethylene naphthalate is preferably used as the base film, and among these, polyethylene terephthalate is most suitable.
These resins may be used alone, a plurality of resins may be blended or laminated, and known additives for resins such as antistatic agents, pigments, fillers, plasticizers and the like may be added. . The base sheet is preferably uniaxially stretched or biaxially stretched from the viewpoint of strength.
The thickness of these base materials may be the thickness used for normal in-mold transfer, and about 2.5 to 50 μm can be applied, but 4 to 25 μm is preferable in terms of transferability.
As described above, it is necessary to provide a certain degree of flexibility and elongation in consideration of being stretched in the mold.

  As the release layer, known release layers such as silicon oxide, a release resin, a release agent-containing resin, and a resin whose surface is cross-linked can be employed, and silicon oxide is particularly preferable. The release layer is obtained by dispersing or dissolving the release layer composition in a solvent and applying it to at least a part by printing or coating methods such as roll coating, gravure coating, comma coating, pre-coating and drying to form a coating film. To do. A release layer having antistatic properties is preferable. Further, if necessary, it may be heat-dried or aged at a temperature of 30 ° C. to 120 ° C. The thickness of the release layer is usually about 0.01 μm to 5 μm, preferably about 0.5 μm to 3 μm. The thinner the thickness is, the better. However, when the thickness is 0.1 μm or more, better film formation is obtained and the peeling force is stabilized.

The printing ink layer may be a layer made of a known printing ink, such as inorganic pigments and organic pigments such as carbon black and titanium oxide, resins such as rosin-modified phenol and alkyd resin, additives such as dryers and anti-backing agents, Known substances can also be used for solvents such as petroleum solvents and higher alcohols, and drying oils such as linseed oil, tung oil, and soybean oil.
As the printing method, known printing methods such as offset printing, letterpress printing, and gravure printing can be employed, and the printing ink can be any ink that is suitable for those printing methods.
The heat seal layer and the primer layer can be selected from known materials in consideration of the resin to be molded such as acrylic resin, olefin resin, rubber resin, polyvinyl chloride, polyvinylidene chloride, and the formation of these layers. The means is arbitrarily selected from known coating methods.

  In addition, it is also possible to provide a functional layer on the hard coat layer after transfer, and in that case, a weather resistant layer and a flame retardant layer are provided between the release layer and the layer comprising the coating composition in the present invention. Any layer such as an antifouling layer or an antibacterial layer can be formed.

[In-mold molding]
For in-mold molding, the transfer film for in-mold molding of the present invention is prepared, and the base film layer side adheres to the inner surface of the mold and faces the resin side on which the hard coat, printing ink layer and heat seal layer are molded. Thus, the resin is injected into the mold by injection molding or the like, and then the resin surface is molded and brought into close contact with the hard coat layer via the printing ink layer. By this means, the hard coat layer can be provided on the surface of the three-dimensional resin molded product without any defects.

  Although it does not specifically limit as molding resin, For example, well-known shaping | molding things, such as polyolefin resin, such as a polypropylene, (meth) acrylic resin, polystyrene resin, polyacrylonitrile styrene resin, polyacrylonitrile butadiene styrene resin, etc. Resin is used, and it can be used in general applications such as parts such as automobiles, home appliances, and OA products, packaging containers, and building materials in which resin molded bodies are conventionally used.

[Primary curing]
As shown in the above formulas 5 and 6, by the primary curing, the urethane bond and the isocyanate residue of the urethane compound react to form an allophanate bond, or the urea bond and the isocyanate residue react to form a burette bond. The coating film obtained by is sufficiently flexible.
Z represents a residue of a polyvalent isocyanate compound in general and does not represent only a cyclohexane ring, and the polyvalent isocyanate compound is not necessarily limited to a compound having a trivalent isocyanate group. .

The primary curing is performed at a drying temperature of 80 to 150 ° C., preferably 90 to 130 ° C., more preferably 100 to 125 ° C. If the drying temperature is lower than 80 ° C., the coating film is not sufficiently dried and sufficient. A hard coat with hardness cannot be obtained, and if it is higher than 150 ° C., problems such as difficulty in controlling drying occur.
Although depending on the dry film thickness, the drying time is about 20 to 60 minutes. If the drying time is insufficient, the solvent may remain in the coating film or the primary curing reaction may be insufficient.

The dry film thickness is 3 to 50 μm, preferably 4 to 20 μm, more preferably 5 to 10 μm. If it is thinner than 3 μm, it will be difficult to exhibit the performance as a coating film. It becomes difficult to cure the film.
When a layer made of the coating composition of the present invention is provided on a transfer foil and transferred to another object, it is necessary to adjust the film thickness and the like according to the surface properties of the other object.

[Secondary curing]
The coating composition in the present invention is capable of exhibiting desired properties such as a hard coat by completing a cured film by performing secondary curing subsequent to primary curing on the formed uncured coating film.

  Also, when using the in-mold transfer film of the present invention, the coating composition is applied to the transfer foil base sheet, and after temporarily drying, the mold is so that the coating surface faces the molding resin surface. Install in. Next, the resin is injection-molded or cast-molded in the mold, and a coating film is provided on the surface of the molded resin molded body.

Next, the resin molded body is taken out of the mold together with the in-mold transfer film and irradiated with ultraviolet rays for secondary curing. As described in the formulas 7 and 8, the secondary curing is specifically performed by the primary curing, and the vinyl group-containing compound having the allophanate bond or the burette bond is used to convert energy rays such as ultraviolet rays. Irradiates to secondary cure. At this time, radical polymerization occurs between the vinyl groups, whereby the vinyl group-containing compound is intermolecularly crosslinked.
As a result of this cross-linking, the hardness of the flexible coating film formed by primary curing is increased and a hard coat coating layer is formed.
The resin molded body thus obtained is still in a state where the in-mold transfer film itself is adhered to the surface. The film may be peeled off leaving the hard coat layer formed on the surface of the molded resin immediately after molding, but it is also possible to put the film in the state without peeling. In such a case, the film layer peeled off from the hard coat layer functions as a protective film on the surface of the molded body and the surface of the hard coat layer.

Formulation example of coating composition 1 Toluene 20 parts by weight Pentaerythritol triacrylate (PETA) 15 parts by weight Isocyanurate (TKA100) 30 parts by weight Dibutyltin dilaurate 0.05 parts by weight is mixed and stirred at 300 rpm at room temperature for 10 minutes. Thereafter, it was left at room temperature for 12 hours.
Further, 52 parts by weight of methyl ethyl ketone was added, and the mixture was further allowed to stand at room temperature for 12 hours.
In addition to this mixture
2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173) (photopolymerization initiator) 0.6 parts by weight (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819) ( 0.3 parts by weight of photopolymerization initiator) and 0.7 parts by weight of triethylenediamine (urethane reaction accelerating catalyst) 0.7 parts by weight of dibutyltin dilaurate were added and mixed and stirred at 300 rpm for 10 minutes to obtain a coating composition. .
In order to confirm the elongation percentage of the coating film by this coating composition, a coating film was formed on the PET film without using a release layer. This was first cured by heating, and the elongation percentage of the laminate of the obtained PET film and the first cured coating film was 200%. Furthermore, the elongation percentage of the laminated body in which the primary cured coating film was laminated with the secondary cured coating film irradiated with ultraviolet rays was 30%.
In addition, a commercially available hard coat agent was similarly applied on a PET film, and the elongation rate of the laminate having a coating film irradiated so that the cumulative amount of ultraviolet light was 80 mJ / cm ² remained at 30%. The elongation percentage of the laminate having the coating film obtained by irradiation so that the integrated light amount was 800 mJ / cm ² was 3% or less.
These elongation ratios were measured according to JIS C2318 by EZ test (manufactured by Shimadzu Corporation).

[Manufacture of transfer foil and in-mold molding]
A solution (AS-1000) of 3.5% ethyl silicate dissolved in a mixed solvent of ethanol and isopropyl alcohol was applied to one side of a 50 μm thick biaxially stretched polyethylene terephthalate film and dried at 120 ° C. for 30 seconds. After forming a release layer having a thickness of 0.2 μm, the coating composition 1 was applied and heated to a dry film thickness of 6 μm to primarily cure the layer made of the coating composition 1. Further, a heat seal layer made of an acrylic resin was applied and dried so as to have a thickness of 1 μm.

The obtained transfer foil was provided in a resin injection molding mold so that the printing ink layer was on the resin side, and molding was performed by injecting the resin. Since the transfer foil is attached to the surface of the resin molded body taken out from the mold, the polyethylene terephthalate film and the release agent layer are integrally peeled from the primary cured layer of the coating composition 1, A resin molded body was obtained in which a primary cured layer obtained from the coating composition 1 was formed on the surface via a printing ink layer.
Subsequently, the resin molding body surface is irradiated with ultraviolet rays to the layer formed of the coating composition 1 that has been primarily cured to perform secondary curing to obtain a resin molding body on which a desired hard coat layer is formed, Physical properties were measured. The results are shown in Table 1 below.

[Transcription]
Using the primary-cured transfer foil obtained in Example 1, the primary-cured coating composition 1 was transferred to polymethyl methacrylate and a glass plate. Each physical property other than the appearance of the coating film at the corner portion was measured on the surface of the transfer coating film after the transfer and the surface of the transfer coating film that had been secondarily cured by irradiation with ultraviolet rays. The results are shown in Table 1 below. The results were the same as in Example 1 except for the pencil hardness.

[Comparative Example 1]
As Comparative Example 1, a commercially available urethane acrylate hard coat composition was used to prepare the following transfer foil.
The base material used in Example 1 was used as the base material and the release layer.
As a commercially available urethane acrylate hard coat composition, Aurex 344 (Chinese Paint Co., Ltd.) was used. The thicknesses of the release layer and the layer composed of the urethane acrylate hard coat composition were as in Example 1. The thickness was the same as the release layer and the coating composition layer.
The urethane acrylate hard coat composition layer was pre-dried at 100 ° C. for 15 seconds, and then semi-cured by UV irradiation to obtain 80 mJ / cm ² to obtain a transfer foil.
This transfer foil was used by the same molding means as in Example 1 to mold a resin molded body by a blend of polycarbonate and ABS resin.
Next, the resin molded body on which the hard coat layer was formed was obtained by irradiating the layer made of the coating composition 1 on the surface of the resin molded body with ultraviolet rays and performing secondary curing.

表中、○は塗膜の状況に変化がみられないことを示す。

In the table, ○ indicates that there is no change in the state of the coating film.

  According to the coating composition of the present invention, it exhibits sufficient adhesion after transfer of the primary cured coating film, and also has sufficient adhesion, further scratch resistance and abrasion resistance after secondary curing. The comparative example using the conventional coating composition also has sufficient adhesion, scratch resistance, and abrasion resistance, but the pencil hardness after secondary curing is H, whereas in Examples 1 and 2, Although it varies depending on the substrate, it can be said that the present invention exhibits a higher effect as a coating composition for forming a hard coat layer having a hardness of 2H or more.

Further, the surface reflectance is 95% in Examples 1 and 2, whereas it is as low as 92% in Comparative Example 1, and according to the present invention, a coating film with more excellent gloss can be obtained. .
The visual appearance was good in the flat part and the corner part in the coating film of Example 1, whereas the coating film in Comparative Example 1 was good in the flat part, but cracks occurred in the corner part and good. A difficult coating film cannot be formed. In particular, this is because the transfer foil according to the present invention has a high elongation rate.

Regarding the boiling water resistance, in Examples 1 and 2, the coating film was not peeled off, but in Comparative Example 1, a part was peeled off. According to this, it can be said that the hard coat obtained from the coating composition used in the present invention does not deteriorate against boiling water and has a property of strongly adhering to the substrate.
Furthermore, the hard coat layers obtained in Examples 1 and 2 have sufficient heat resistance and warm water resistance, and the coating film does not change even in a temperature cycle test, and various chemical resistances are also good.

Claims (8)

  A coating composition containing a urethane compound or a urea compound obtained by reacting a polyvalent isocyanate compound with a vinyl group-containing alcohol or vinyl group-containing amine having an OH equivalent or amine equivalent smaller than the NCO equivalent of the polyvalent isocyanate compound. An in-mold transfer film that is applied on top and is primarily cured.   The in-mold transfer film according to claim 1, wherein the polyvalent isocyanate compound is tolylene diisocyanate.   The in-mold transfer film according to claim 1, wherein the vinyl group-containing alcohol is an acryloyl group-containing monohydric alcohol.   The in-mold transfer film according to claim 1, wherein the vinyl group-containing amine is an acryloyl group-containing monovalent amine.   The in-mold transfer film according to any one of claims 1 to 4, wherein the coating composition contains a ketone solvent.   The in-mold transfer film according to any one of claims 1 to 4, comprising a photopolymerization initiator.   The shaping | molding method using the in-mold transfer film in any one of Claims 1-6.   A molded article obtained by the method according to claim 7.