JP7244172B2 - Curable resin composition, film using same, and molded article using film - Google Patents

Description

The present invention relates to a curable resin composition. Furthermore, the present invention relates to a molded film and molded article using a cured coating obtained by curing the curable resin composition.

The surface of resin moldings and plastic moldings such as automobile interiors, automobile exteriors, electrical appliances, etc. is required to have scratch resistance so that it is not damaged by impact or is hardly damaged by impact. Therefore, for the purpose of improving the scratch resistance of the surface of these molded products, it is widely practiced to provide a scratch-resistant protective layer. In the past, a scratch-resistant protective layer was provided by coating a scratch-resistant component after obtaining a resin molded product or plastic molded product by an injection molding method or the like. However, if a resin molded article or plastic molded article having a scratch-resistant protective layer can be obtained at once by injection molding, it is economically advantageous because the number of molding processes can be reduced. Therefore, attempts have been made to develop a curable composition capable of forming a protective layer having both high elongation and scratch resistance that can withstand the injection molding method.

Japanese Patent No. 6123428 describes an active energy ray capable of forming a cured film having flexibility, breaking strength, mechanical strength, scratch repairability, scratch resistance, etc. that can follow deformation during three-dimensional processing. A curable resin composition is disclosed. The active energy ray-curable resin composition contains a polyisocyanate, a polycarbonate polyol, and a urethane (meth)acrylate oligomer that is a reaction product of a hydroxyalkyl (meth)acrylate, and the cured film has a predetermined tensile modulus. It is characterized by having a value.

The active energy ray-curable resin composition according to Patent Document 1 can form a cured film having flexibility and scratch resistance as described above, but has a problem of whitening upon contact with chemicals. Therefore, the present invention provides a curable resin composition capable of forming a cured film having both high elongation to withstand deformation in injection molding methods including insert molding methods, scratch resistance, and chemical resistance. intended to

The curable resin composition in the embodiment of the present invention comprises a polyurethane (meth)acrylate compound (A) having a urethane bond equivalent of 210 g/mol or less, a polymerization initiator (B), and an aprotic polar solvent (C ) is a curable resin composition containing. Here, the polyurethane (meth)acrylate compound (A) comprises the following compounds: a polyisocyanate compound (a1), a polyol compound (a2) having 1 to 6 carbon atoms, and a hydroxyalkyl (meth)acrylate compound (a3). It is characterized by being a compound formed by a reaction.
Another embodiment of the present invention is a molded film comprising a cured coating obtained by curing a curable resin composition and a substrate.
Still another embodiment of the present invention is a cured film obtained by curing a curable resin composition, and a molded article having a cured film obtained by curing a curable resin composition on its surface.

A molded film formed using the curable resin composition of the present invention has sufficient elongation in thermoforming such as injection molding. A molded product obtained by using the molded film of the present invention for processing the surface of a resin molded product or a plastic molded product has a cured coating adhered to the surface of the molded product, effectively protecting the surface.

Embodiments of the invention are described below. One embodiment of the present invention comprises a polyurethane (meth)acrylate compound (A) having a urethane bond equivalent of 210 g/mol or less, a polymerization initiator (B), and an aprotic polar solvent (C). It is a curable resin composition.

In the present embodiment, the curable resin composition is present in a liquid state at room temperature, and is triggered by irradiation with active energy such as ultraviolet rays, infrared rays, and X-rays, addition of heat energy, addition of chemical substances, etc. It is a mixture mainly composed of resins or plastics or these raw material monomers, which can form a cured product or a cured film. Curable resin compositions are used in a wide range of applications such as paints, sealants, encapsulants and adhesives, and must satisfy various performance requirements depending on the application. The cured product of the curable resin composition of the present embodiment is used as a film for processing or decorating the surface of molded articles such as resins, plastics, and metals, and the cured film adheres to the surface of the molded article. It is difficult to peel off and can prevent the formation of scratches due to impact from the outside.

The curable resin composition of the present embodiment contains a polyurethane (meth)acrylate compound (A) having a urethane bond equivalent of 210 g/mol or less. A polyurethane (meth)acrylate compound is a polymer having a urethane bond in the molecule and a polymerizable group selected from an acrylic group or a methacrylic group, that is, a polymer or an oligomer. The polyurethane (meth)acrylate compound (A) contains an acrylic group or a methacrylic group that is cleaved to initiate radical polymerization by irradiation with active energy rays, application of heat, or addition of a polymerization initiator. The urethane bond equivalent of the polyurethane (meth)acrylate compound (A) is 210 grams/mole or less. Here, the urethane bond equivalent means the weight average molecular weight of the polyurethane (meth)acrylate compound (A) (that is, the weight of 1 mol of the polyurethane (meth)acrylate compound (A)), and the weight of the polyurethane (meth)acrylate compound (A). is the ratio to the number of urethane bonds present in the unit of gram/mole. A small urethane bond equivalent value means that many urethane bonds are present in the molecule of the polyurethane (meth)acrylate compound (A).

When a polyurethane (meth)acrylate compound having a small urethane bond equivalent value is used as (A), many urethane bonds are present in the cured film polymer obtained by curing the curable resin composition. When the urethane bond equivalent of the polyurethane (meth)acrylate compound (A) is 210 g/mol or less, the number of urethane bonds sufficient to impart chemical resistance to the cured film can be ensured.

In the embodiment, the polyurethane (meth)acrylate compound as component (A) comprises a polyisocyanate compound (a1), a polyol compound (a2) having 1 to 6 carbon atoms, and a hydroxyalkyl (meth)acrylate compound (a3). A compound formed by a reaction is preferred. The polyisocyanate compound (a1) is a compound having two or more isocyanato groups (--N=C=O) in one molecule. As the polyisocyanate compound (a1), it is particularly preferable to use a diisocyanate compound having two isocyanato groups in the molecule. Here, as diisocyanate compounds, bis (isocyanatomethyl) cyclohexane, cyclohexane diisocyanate, diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (tolylene diisocyanate, TDI), xylylene diisocyanate (XDI), isophorone diisocyanate ( IPDI), cyclohexyl diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, etc., and one or more of these can be used.

The polyol compound (a2) is a compound having two or more hydroxyl groups (--OH) in one molecule. In embodiments, the polyol compound (a2) preferably has 1 to 6 carbon atoms. By using a relatively low-molecular-weight polyol compound as (a2), the number of urethane bonds in the polyurethane (meth)acrylate compound (A) can be increased. That is, the urethane bond equivalent of the polyurethane (meth)acrylate compound (A) can be adjusted by adjusting the carbon number of the polyol compound (a2). Examples of such polyol compounds include methanediol, ethanediol, n-propanediol, isopropanediol, n-butanediol, isobutanediol, t-butanediol, n-pentanediol, n-hexanediol, dihydroxycyclohexane, and the like. , aliphatic or alicyclic triol compounds such as 1,2,4-butanetriol, aromatic diol compounds such as catechol, resorcinol, and hydroquinone, hydroxyquinol, phloroglucinol, pyrogallol, etc. and one or more of them can be used.

The hydroxyalkyl (meth)acrylate compound (a3) is a compound having a hydroxyalkyl group (an alkyl group having a hydroxyl group) and an acryl group or a methacryl group in one molecule. Hydroxyalkyl (meth)acrylate compounds include hydroxymethyl acrylate, hydroxymethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, and the like. One or more of these can be used.

The isocyanato group present in (a1) above, the hydroxyl group present in (a2), and the hydroxyl group present in (a3) are reacted to form a urethane bond to obtain a polyurethane (meth)acrylate compound (A). can be generated. Preferably, the polyurethane (meth)acrylate compound (A) is produced by first reacting the (a1) component with the (a2) component and then adding the (a3) component. The polyurethane (meth)acrylate compound (A) has a radically polymerizable group (acrylic group or methacrylic group) derived from (a3). The reaction of this radically polymerizable group contributes to curing of the curable resin composition of the embodiment.

The curable resin composition of the embodiment contains a polymerization initiator (B) in addition to the polyurethane (meth)acrylate compound (A). A polymerization initiator is a compound that initiates a polymerization reaction of a monomer in response to a stimulus such as irradiation of light or application of heat. In the curable resin composition of the embodiment, it is preferable to use a photopolymerization initiator that initiates polymerization upon irradiation with light including ultraviolet rays, electron beams, and visible light. As a photopolymerization initiator, a photoradical polymerization initiator that generates radical active species upon irradiation with light (e.g., acetylbenzene, dimethoxybenzyl, dibenzoyl, benzoin, benzophenone, benzoylbenzoic acid, bis(dimethylamino)benzophenone, bis(diethylamino) ) benzophenone, chlorothioxatone, ethylanthraquinone), photocationic polymerization initiators that generate cationic active species (e.g., bis(4-tert-butylphenyl)iodonium hexafluorophosphate, bis(4-fluorophenyl)iodonium triflate , diphenyliodonium hexafluorophosphate, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-triazine, 4-nitrobenzenediazonium tetrafluoroborate) , photoanionic polymerization initiators (acetophenone-O-benzoyloxime, 1,2-bis(4-methoxyphenyl)-2-oxoethyl cyclohexylcarbamate, nifedipine) that generate anionic active species can be used. Commercially available products such as Irgacure (BASF) can be used as the photopolymerization initiator. Irgacure 184 (1-hydroxycyclohexylphenyl ketone), Irgacure 907 (2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one), Lucirin TPO (2,4,6-trimethyl benzoyldiphenylphosphine oxide) and the like can be used. Moreover, these may be used alone or in combination of two or more.

The curable resin composition of the embodiment contains an aprotic polar solvent (C). An aprotic polar solvent is a polar solvent that does not have a proton-donating group in its molecule. Aprotic polar solvents include ethers such as diethyl ether and tetrahydrofuran, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, dimethyl sulfoxide, N,N-dimethylformamide and hexamethylphosphoric triamide. etc. The aprotic polar solvent (C) can be used by mixing one or more of these, but from the viewpoint of dielectric constant, it should contain at least one of N,N-dimethylformamide and dimethylsulfoxide. is preferred. By containing the aprotic polar solvent (C) in the curable resin composition, the intermolecular interaction of the polyurethane (meth)acrylate compound (A) contained in the curable resin composition is inhibited. be able to. Therefore, the polyurethane (meth)acrylate compound (A) is uniformly distributed in the curable resin composition. A uniform cured film can be formed by curing such a curable resin composition. The aprotic polar solvent (C) volatilizes during curing of the curable resin composition. Using the curable resin composition of the present embodiment, which is a combination of the polyurethane (meth)acrylate compound (A) having a predetermined urethane bond equivalent value as described above and the aprotic polar solvent (C), A strong cured film can be formed.

The curable resin composition of the embodiment may further contain an ethylenically unsaturated compound (D) having one or more radically polymerizable groups in the molecule. Here, the ethylenically unsaturated compound is a compound having at least one ethylenically unsaturated group (-C=C-). The ethylenically unsaturated compound (D) preferably has one or more radically polymerizable groups in its molecule. The radically polymerizable group is cleaved by irradiation with active energy rays, application of heat, or addition of a polymerization initiator, represented by vinyl group, acrylic group, methacrylic group, acryloyl group, methacryloyl group, allyl group, etc., as described above. is a double or triple bond that initiates radical polymerization as a Examples of such ethylenically unsaturated compounds (D) include ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, di Polyfunctional (meth)acrylate compounds typified by methylolpropane tetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate, typified by hydroxybutyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxyethyl (meth)acrylate and (meth)acrylamides represented by (meth)acryl-based monomers, (meth)acrylamide, and dimethyl(meth)acrylamide. In addition, a polymer having at least one ethylenically unsaturated group can be used as the ethylenically unsaturated compound (D) as long as it does not affect the embodiment. By changing the ethylenically unsaturated compound (D) variously, the elongation, hardness, adhesion to the substrate, etc. of the cured film can be changed. Accordingly, the ethylenically unsaturated compound (D) may or may not be used depending on the type of substrate to which the cured coating is applied, the molding method, the intended use of the finished molded product, and the like.

In addition to the above components, the curable resin composition of the embodiment contains additives that are usually contained in curable resin compositions (for example, dyes, pigments, plasticizers, dispersants, preservatives, matting agents, antistatic agents , flame retardants, ultraviolet absorbers, light stabilizers, antifouling agents, antiblocking agents, antibacterial agents, and inorganic particles).

The curable resin composition of the embodiment can be diluted by blending a protic polar solvent depending on the application. As the protic polar solvent, alcohols such as methanol, ethanol, 1-propanol, isopropanol, ethylene glycol methyl ether, and propylene glycol monomethyl ether can be used singly or in combination of two or more. In addition, what diluted the curable resin composition of embodiment with a protic polar solvent may also be called "curable resin composition" in this specification.

A suitable curable resin composition prepares a polyurethane (meth)acrylate compound (A), a polymerization initiator (B), and an appropriate amount of an aprotic polar solvent ( It can be produced by mixing C) and optionally an ethylenically unsaturated compound (D), and optionally diluting with a protic polar solvent.

Here, the content of the polyurethane (meth)acrylate compound (A) (nonvolatile matter) is the weight of the curable resin composition (that is, the weight of the component (A), the component (B), the component (C), and the component (D)). 15 to 50%, preferably 20 to 45%, based on the total weight).
The content of the polymerization initiator (B) is 0.5-5%, preferably 1-3%, based on the weight of the curable resin composition.
The content of the aprotic polar solvent (C) is 40% to 80%, preferably 45% to 75%, based on the weight of the curable resin composition.
The content of the ethylenically unsaturated compound (D) is 5-20%, preferably 10-20%, based on the weight of the curable resin composition.
The curable resin composition of the embodiment can be diluted by blending a protic polar solvent according to the application. In this case, the curable resin composition containing the component (A), the component (B), the component (C), and the component (D) is mixed with a protic polar solvent in an amount of 1.1 to 5 times, preferably 1.3 times. It can be diluted to double to triple the volume. That is, the content of the polyurethane (meth)acrylate compound (A) (nonvolatile matter) is the total weight of the curable resin composition containing the solvent (that is, component (A), component (B), component (C), component ( D), the total weight of the diluent solvent) can be 5 to 30%, preferably 10 to 25%.
The content of the polymerization initiator (B) is 0.1 to 3%, preferably 0.5 to 2%, based on the total weight of the solvent-containing curable resin composition.
The content of the aprotic polar solvent (C) is 20% to 60%, preferably 25% to 60%, based on the total weight of the solvent-containing curable resin composition.
The content of the ethylenically unsaturated compound (D) is 3 to 15%, preferably 5 to 10%, based on the total weight of the solvent-containing curable resin composition.

The curable resin composition of embodiments can be applied to a suitable substrate surface and cured thereon to form a cured coating. The thickness of the cured coating can be varied depending on the application, but is generally 1-20 μm, preferably 1-10 μm. Examples of substrates for curing the curable resin composition include glass, plastic, and metal. can be formed. As the substrate, for example, an acrylic resin or a polycarbonate resin whose outermost layer is covered with an acrylic resin can be used. Application of the curable resin composition to the surface of the base material can be carried out as appropriate by conventional coating methods. A cured film can be formed by heating the applied curable resin composition. Heating of the curable resin composition causes polymerization or copolymerization of the polyurethane (meth)acrylate compound (A) and optionally the ethylenically unsaturated compound (D) by the action of the polymerization initiator (B) in the curable resin composition. It may be heated to a temperature sufficient to initiate the polymerization reaction. Depending on the types of (A) and (D) and the polymerization initiator (B) used, the copolymerization reaction can be initiated by heating to about 80 to 150° C., preferably about 100 to 150° C. can. The curable resin composition-coated material can be heated by a heating device such as a burner or an oven, or by a heating method using hot air such as a dryer.

In addition, the curable resin composition of the embodiment is applied to a substrate surface, and the applied surface is irradiated with an active energy ray to obtain a polyurethane (meth)acrylate compound (A) and optionally an ethylenically unsaturated compound (D). may initiate the polymerization or copolymerization reaction of Examples of active energy rays to be irradiated include visible light, ultraviolet light, infrared light, alpha rays, beta rays, gamma rays, and X rays.

In this manner, the curable resin composition of the embodiment can be cured on a plastic substrate to form a cured film, thereby forming a molded film. The molded film of the embodiment can be used as a film for processing the surface of molded articles such as plastics. The formed film of the embodiment may have patterns, designs, patterns, colors, etc., and may be transparent. A molded film having a pattern or the like is called a decorative film, and is suitably used for applying a pattern or the like to the surface of a molded product. The molded film of the embodiment can be loaded into an injection mold, and a cured coating can be attached to a molded product at the same time as the injection molding (insert molding method). Alternatively, the molded film of the embodiment can be adhered to the surface of a molded product, and the base material can be peeled off to transfer a cured coating having a pattern or pattern (transfer method). The cured film obtained by curing the curable resin composition of the embodiment has heat resistance to injection molding, sufficient elongation to conform to the surface of the molded product, and adheres to the surface of the molded product. can be used to form a strong coating.

(1) Preparation of curable resin composition (1-1) Synthesis of polyurethane (meth)acrylate compound (A-1) Into a 300 mL eggplant-shaped flask, dicyclohexylmethane-4,4'-diisocyanate 30 was added as component (a1). 0 parts by weight, 6.9 parts by weight of ethylene glycol as component (a2), 98.7 parts by weight of N,N-dimethylformamide as component (C), and 0.024 parts by weight of dioctyltin dilaunate as a catalyst. was charged and reacted at 70° C. for 6 hours while stirring. After completion of the reaction, 5.4 parts by weight of pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronix M-306) is added as the component (a3) and reacted at 60° C. for 6 hours to obtain a radically polymerizable group. A polyurethane acrylate (A-1) was obtained.
Weight average molecular weight = 12100, non-volatile content = 30%, urethane bond equivalent = 170 grams/mole

The polyurethane (meth)acrylate compound synthesized in Examples and Comparative Examples described below is a mixture of the polyurethane (meth)acrylate compound and an aprotic polar solvent as a reaction solvent. "Non-volatile matter" indicates a substantial proportion of the polyurethane (meth)acrylate compound contained in the mixture obtained by the reaction. For example, in the above polyurethane acrylate (A-1), "non-volatile content = 30%" means that a mixture of 30% polyurethane acrylate (A-1) and 70% N,N-dimethylformamide as a reaction solvent is obtained. , means that this was used as the (A-1) component. Syntheses of all polyurethane (meth)acrylate compounds below are similarly described.

(1-2) Synthesis of polyurethane (meth)acrylate compound (A-2) In a 300 mL eggplant-shaped flask, 30.0 parts by weight of dicyclohexylmethane-4,4'-diisocyanate as component (a1) and component (a2) were added. 6.6 parts by weight of ethylene glycol as component (C), 110.0 parts by weight of N,N-dimethylformamide as component (C), and 0.024 parts by weight of dioctyltin dilaunate as a catalyst were charged and stirred at 70° C. for 6 hours. time reacted. After completion of the reaction, 11.2 parts by weight of pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronix M-306) was added as the component (a3), and reacted at 60°C for 6 hours to obtain a radically polymerizable group. A polyurethane acrylate (A-2) was obtained.
Weight average molecular weight = 5600, non-volatile content = 30%, urethane bond equivalent = 179 grams/mole

(1-3) Synthesis of polyurethane (meth)acrylate compound (A-3) In a 300 mL eggplant-shaped flask, 30.0 parts by weight of dicyclohexylmethane-4,4'-diisocyanate as component (a1) and component (a2) were added. 6.6 parts by weight of ethylene glycol as component (C), 110.0 parts by weight of N,N-dimethylformamide as component (C), and 0.024 parts by weight of dioctyltin dilaunate as a catalyst were charged and stirred at 70° C. for 6 hours. time reacted. After completion of the reaction, 37.6 parts by weight of pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronix M-306) is added as the component (a3) and reacted at 60° C. for 6 hours to obtain a radically polymerizable group. A polyurethane acrylate (A-3) was obtained.
Weight average molecular weight = 5000, non-volatile content = 40%, urethane bond equivalent = 181 grams/mole

(1-4) Synthesis of polyurethane (meth)acrylate compound (A-4) In a 300 mL eggplant-shaped flask, 30.0 parts by weight of dicyclohexylmethane-4,4'-diisocyanate as component (a1) and component (a2) were added. 9.6 parts by weight of 1,4-butanediol as component (C), 118.6 parts by weight of N,N-dimethylformamide as component (C), and 0.024 parts by weight of dioctyltin dilaunate as a catalyst were charged and stirred. The reaction was carried out at 70°C for 6 hours. After completion of the reaction, 11.2 parts by weight of pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronix M-306) was added as the component (a3), and reacted at 60°C for 6 hours to obtain a radically polymerizable group. A polyurethane acrylate (A-4) was obtained.
Weight average molecular weight = 5600, non-volatile content = 30%, urethane bond equivalent = 194 grams/mole

(1-5) Synthesis of polyurethane (meth)acrylate compound (A-5) In a 300 mL eggplant-shaped flask, 30.0 parts by weight of dicyclohexylmethane-4,4'-diisocyanate as component (a1) and component (a2) were added. 12.5 parts by weight of 1,6-hexanediol as component (C), 125.3 parts by weight of N,N-dimethylformamide as component (C), and 0.024 parts by weight of dioctyltin dilaunate as a catalyst were charged and stirred. The reaction was carried out at 70°C for 6 hours. After completion of the reaction, 11.2 parts by weight of pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronix M-306) was added as the component (a3) and reacted at 60° C. for 6 hours to form a polyurethane acrylate compound (A-5). ).
Weight average molecular weight = 5600, non-volatile content = 30%, urethane bond equivalent = 208 grams/mole

(1-6) Synthesis of polyurethane (meth)acrylate compound (A'-1) A polyurethane (meth)acrylate compound having a large urethane bond equivalent was synthesized. In a 500 mL eggplant-shaped flask, 30.0 parts by weight of isophorone diisocyanate, 57.2 parts by weight of polycarbonate diol (manufactured by Asahi Kasei Corporation, trade name: Duranol T4691), 4.3 parts by weight of 1,4-butanediol, 150.0 parts by weight of methyl ethyl ketone (MEK) as a reaction solvent and 0.005 parts by weight of dioctyltin dilaunate as a catalyst were charged and reacted at 80° C. for 9 hours while stirring. After the reaction was completed and cooled to 60° C., 0.03 parts by weight of dioctyltin dilaunate, 0.05 parts by weight of methylhydroquinone and 10.6 parts by weight of methyl ethyl ketone were added, and 8.1 parts by weight of 2-hydroxyethyl methacrylate was added dropwise. A reaction was carried out at 70° C. for 10 hours to obtain a polyurethane methacrylate compound (A′-1).
Weight average molecular weight = 4250, non-volatile content = 40%, urethane bond equivalent = 371 grams/mole

(1-7) Synthesis of polyurethane (meth)acrylate compound (A'-2) A polyurethane (meth)acrylate compound having a large urethane bond equivalent was synthesized. In a 500 mL eggplant-shaped flask, 77.7 parts by weight of dicyclohexylmethane-4,4'-diisocyanate, 45.1 parts by weight of glycerin monomethacrylate (manufactured by NOF Corporation, trade name: Blemmer GLM), and a reaction solvent 204.8 parts by weight of ethyl acetate (EA) and 0.004 parts by weight of dioctyltin dilaunate as a catalyst were charged and reacted at 60° C. for 6 hours while stirring. After completion of the reaction, 14.6 parts by weight of pentaerythritol triacrylate (manufactured by Toagosei Co., Ltd., trade name: Aronix M-306) was added and reacted at 60°C for 6 hours to obtain a polyurethane acrylate compound (A'-2). .
Weight average molecular weight = 9200, non-volatile content = 40%, urethane bond equivalent = 222 grams/mole

The above (A-1) to (A-5) and (A'-1) and (A'-2), Irgacure 907 (BASF) as a polymerization initiator (B), and optionally an ethylenically unsaturated compound ( Pentaerythritol triacrylate (Toagosei Chemical Co., Ltd., Aronix M-306) as D) and propylene glycol monomethyl ether (PGM) or methyl ethyl ketone (MEK) as a solvent are blended in the weight ratios shown in Table 1. , curable resin compositions according to Examples 1 to 6 of the present invention and curable resin compositions according to Comparative Examples 1 to 4 were prepared. As described above, the above (A-1) to (A-5), (A'-1) and (A'-2) are a polyurethane (meth)acrylate compound and an aprotic polar solvent ( C) is a mixture. The numerical values of (A-1) to (A-5) and (A'-1) and (A'-2) in Tables 1 and 2 are the total of these components (that is, the aprotic polar solvent (C) ) is the weight ratio. The numbers in parentheses are the weight ratios of only the non-volatile matter (that is, polyurethane (meth)acrylate).

(2) Production of Cured Film of Curable Resin Composition As a substrate for forming a cured film of the curable resin composition, a polycarbonate film whose outermost layer was covered with an acrylic resin was used. Each of the above curable resin compositions was applied to a substrate by a bar coating method so that the film thickness after curing was 4 μm. The substrate coated with the curable resin composition was dried in an oven at 100° C. for 1 minute, and then irradiated with ultraviolet rays as active energy rays to cure the curable resin composition. This gave a molded film with a cured coating.

(3) Performance Evaluation of Molded Film (3-1) Appearance Evaluation For the molded film of each example, the haze value was measured using a haze meter conforming to JIS K7136. A larger haze value indicates more opaqueness, and a smaller haze value indicates more transparency.

(3-2) Evaluation of Adhesion According to JIS K 5600-5-6, the presence or absence of peeling of the cured coating on the formed film was visually evaluated as follows.
Pass: No peeling observed Fail: Partial or complete peeling

(3-3) Evaluation of Adhesion after Heating Further, each formed film was immersed in boiling water for 30 minutes, and the presence or absence of peeling of the cured coating on the formed film was visually observed in accordance with JIS K 5600-5-6. rated the street.
Pass: No peeling observed Fail: Partial or complete peeling

(3-4) Evaluation of Scratch Resistance For each molded film obtained, a load of 250 g/cm ² was applied to steel wool #0000 and reciprocated 10 times, and the haze value was measured using a haze meter. A difference in haze value before and after the scratch resistance test was determined. A smaller value means a higher scratch resistance.

(3-5) Evaluation of chemical resistance For each molded film obtained, 0.2 g of a commercially available sunscreen cream (Ultra Sheer Dry Touch Sunscreen SPF45, manufactured by Neutrogena) was applied to an area of 1 cm ² and 80 ℃ for 1 hour. After that, the applied sunscreen cream was washed with a large amount of water, and changes in the appearance of the cured film were visually observed.
High: No change in appearance is observed Medium: Changes such as whitening are observed in part of the appearance Low: Changes such as whitening are observed in the appearance

(3-6) Evaluation of stretchability Each molded film obtained was subjected to a tensile test (sample size: 200 mm × 10 mm, distance between chucks: 110 mm, pulling speed: 50 mm / min) at a high temperature (150 ° C.). The elongation at break was defined as the point at which cracks were visually observed in the cured film, and the extensibility of the formed film was evaluated from the results.

In addition, the numerical value in the parenthesis in Table 1 is the component amount of a non-volatile matter. For example, the numerical value "46.1" described in the A-1 column of Table 1 Example 1 is the polyurethane acrylate of A-1 and the reaction solvent (that is, the aprotic polar solvent (C)) DMF is 46.1 parts by weight, of which the amount of polyurethane acrylate A-1 is 13.8 parts by weight. Polyurethane (meth)acrylate, which is component (A), is used in the form of a mixture of polyurethane (meth)acrylate and aprotic polar solvent (C) for the convenience of production. described in The curable resin composition of Example 1 contains 46.1 parts by weight of A-1 dissolved in an aprotic polar solvent (C), 0.9 parts by weight of a polymerization initiator (B), and an ethylenically unsaturated monomer. It was prepared by mixing 7.7 parts by weight of (D) and 45.3 parts by weight of a dilution solvent. Similarly, the numbers in parentheses in Table 2 are the amounts of non-volatile components. For example, the numerical value "53.9" described in the A'-1 column of Table 2 Comparative Example 1 is the polyurethane acrylate of A'-1 and the reaction solvent (that is, the aprotic polar solvent (C)). It means that the total amount with a certain MEK is 53.9 parts by weight, and the amount of polyurethane methacrylate A'-1 is 21.6 parts by weight. The curable resin composition of Comparative Example 1 contains 53.9 parts by weight of A'-1 dissolved in an aprotic polar solvent (C), 1.2 parts by weight of the polymerization initiator (B), and 44 parts of MEK. .9 parts by weight were mixed.

The abbreviations in the table have the following meanings:
Irgacure 907: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (BASF)
M-306: Pentaerythritol triacrylate (Toagosei)
PGM: propylene glycol monomethyl ether MEK: methyl ethyl ketone DMF: N,N-dimethylformamide EA: ethyl acetate

All of the cured films according to the examples of the present invention are excellent in adhesiveness and maintain the adhesiveness even after heating. The curable resin composition according to the examples of the present invention can form a cured coating excellent in scratch resistance and chemical resistance. The molded film using the curable resin composition according to the examples of the present invention has a high elongation at break, that is, stretchability, and has sufficient elongation to withstand insert molding and the like. is suggested. On the other hand, a molded film using a curable resin composition according to a comparative example using a polyurethane (meth)acrylate (A) whose urethane bond equivalent does not satisfy the stipulations of the present invention has adhesion, scratch resistance, and chemical resistance. However, either the elasticity or stretchability was not sufficient.

Claims (5)

A nitrogen atom -containing monofunctional monomer containing a polyurethane (meth)acrylate compound (A) having a urethane bond equivalent of 170 to 194 g/mol , a polymerization initiator (B), and an aprotic polar solvent (C) A curable resin composition that does not contain
The polyurethane (meth)acrylate compound (A) is a polyisocyanate compound (a1) selected from dicyclohexylmethane-4,4'-diisocyanate, a polyol compound (a2) having 1 to 6 carbon atoms, and a hydroxyalkyl (meth) A compound obtained by reacting an acrylate (a3),
Based on the weight of the curable resin composition, the polyurethane (meth)acrylate compound (A) is 15 to 50%, the polymerization initiator (B) is 0.5 to 5%, the aprotic polar solvent (C ), is contained 40 to 80%, curable resin composition . 2. The curable resin composition according to claim 1 , further comprising an ethylenically unsaturated compound (D) having one or more radically polymerizable groups in the molecule. 3. The curable resin composition according to claim 1, further comprising a protic polar solvent. A molded film comprising a cured coating obtained by curing the curable resin composition according to any one of claims 1 to 3 , and a substrate. A molded article having on its surface a cured film obtained by curing the curable resin composition according to any one of claims 1 to 3 .