阅读说明：本技术 涂料组合物、装饰薄膜及装饰成形品 (Coating composition, decorative film and decorative molded article ) 是由 松山展也 于 2020-05-07 设计创作，主要内容包括：提供一种电离辐射线固化型的涂料组合物,其能够形成具有优异的加温伸展性(例如30％以上)、且耐溶剂性及耐化学药品性优异的固化膜,并且所述组合物可以含有醇类作为稀释溶剂。该电离辐射线固化型的涂料组合物含有：具有6个以上(甲基)丙烯酰基的、重均分子量为3000～50000的氨基甲酸酯(甲基)丙烯酸酯低聚物(A1),氨基甲酸酯(甲基)丙烯酸酯低聚物(A1)为有机硅改性低聚物,所述有机硅改性低聚物具有：源自具有羟基及3个以上(甲基)丙烯酰基的多官能(甲基)丙烯酸酯单体的结构单元(a)、源自具有2个以上羟基的分子量100以下的醇的结构单元(b)、源自异佛尔酮二异氰酸酯的结构单元(c)、和源自甲醇改性聚硅氧烷的结构单元(d)。(Provided is an ionizing radiation-curable coating composition which is capable of forming a cured film having excellent thermal stretchability (e.g., 30% or more) and excellent solvent resistance and chemical resistance, and which may contain an alcohol as a diluting solvent. The ionizing radiation-curable coating composition contains: a urethane (meth) acrylate oligomer (A1) having 6 or more (meth) acryloyl groups and a weight average molecular weight of 3000 to 50000, wherein the urethane (meth) acrylate oligomer (A1) is an organosilicon modified oligomer having: a structural unit (a) derived from a polyfunctional (meth) acrylate monomer having a hydroxyl group and 3 or more (meth) acryloyl groups, a structural unit (b) derived from an alcohol having a molecular weight of 100 or less and having 2 or more hydroxyl groups, a structural unit (c) derived from isophorone diisocyanate, and a structural unit (d) derived from a carbinol-modified polysiloxane.)

1. A coating composition of ionizing radiation curing type,

it comprises the following components: a urethane (meth) acrylate oligomer (A1) having 6 or more (meth) acryloyl groups and a weight average molecular weight of 3000 to 50000,

the urethane (meth) acrylate oligomer (a1) is an organosilicon modified oligomer having: a structural unit (a) derived from a polyfunctional (meth) acrylate monomer having a hydroxyl group and 3 or more (meth) acryloyl groups, a structural unit (b) derived from an alcohol having a molecular weight of 100 or less and having 2 or more hydroxyl groups, a structural unit (c) derived from isophorone diisocyanate, and a structural unit (d) derived from a carbinol-modified polysiloxane,

the urethane (meth) acrylate oligomer (A1) having a content of the structural unit (d) of 0.1 to 10% by mass based on the total of the structural units (a) to (c),

the content of the urethane (meth) acrylate oligomer (a1) is 50% by mass or more based on the solid content of the coating material.

2. The coating composition according to claim 1, wherein the weight average molecular weight of the methanol-modified polysiloxane is 3000 or less.

3. The coating composition according to claim 1 or 2, wherein the polyfunctional (meth) acrylate monomer is at least any one of pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate.

4. The coating composition according to any one of claims 1 to 3, wherein the alcohol is at least one of ethylene glycol and glycerol.

5. The coating composition according to any one of claims 1 to 4, further comprising an inorganic filler having an average primary particle diameter of 1 to 100nm,

the content of the inorganic filler is 1 to 50 mass% based on the solid content of the coating.

6. A decorative film comprising:

a plastic substrate in the form of a film, and

a cured film formed by curing a coating film formed from the coating composition according to any one of claims 1 to 5, provided on at least one surface of the plastic substrate.

7. A decorative molded article comprising:

a molded article body made of resin, and

a cured film formed by curing a coating film formed from the coating composition according to any one of claims 1 to 5, provided on at least a part of the surface of the molded article main body.

Technical Field

The present invention relates to an ionizing radiation curable coating composition, and a decorative film and a decorative molded article using the same.

Background

As a material for constituting interior and exterior trims of vehicles, demand for a decorative film is increasing. Under such circumstances, a protective film using an ionizing radiation curable coating composition for a thin film, which is free from yellowing and has excellent weather resistance and chemical resistance, has been widely used as a decorative thin film, and is regarded to have excellent hardness properties.

The decorative film is generally produced by various molding methods such as film insert molding and in-mold molding. However, with the diversification of the shape of the object to be decorated, the decorative film is required to have flexibility and stretchability (hereinafter, also referred to as "heating stretchability") in a heat molding step (under a temperature condition of several tens ℃ or higher). Therefore, the protective film of the decorative film is also required to have thermal stretchability.

In order to achieve both chemical resistance and thermal stretchability, for example, a method has been proposed in which a protective film is formed from an uncured or semi-cured film, and the protective film is completely cured after molding (patent document 1). Further, a method has been proposed in which a resin composition for forming a protective film contains components such as isocyanate and amine in advance, and is heated to completely cure a portion having a defective cure (patent document 2). Further, there have been proposed a method of blending a thermoplastic resin into an ionizing radiation curable coating composition (patent document 3) and a molding film having a hard coat layer in which crosslinking density is controlled by providing a blend of components such as a monomer (patent document 4).

Further, an active energy ray-curable composition containing a urethane acrylate oligomer having a characteristic composition, and a thin film having a cured film formed by curing the composition have been proposed (patent documents 5 and 6).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3233595

Patent document 2: japanese laid-open patent publication No. 57-126819

Patent document 3: japanese patent No. 5151179

Patent document 4: japanese patent laid-open publication No. 2011-148964

Patent document 5: japanese patent laid-open publication No. 2016-186039

Patent document 6: japanese patent laid-open publication No. 2018-111793

Disclosure of Invention

Problems to be solved by the invention

However, in the method proposed in patent document 1, the molding machine does not necessarily have a curing device, and thus the method is somewhat less versatile, and depending on the shape of the object to be decorated, a position where the object is not completely irradiated with the active energy ray may be generated, and poor curing may easily occur. In addition, in the method proposed in patent document 2, the pot life of the resin composition is easily shortened, and variation in final physical properties is easily caused. Furthermore, the chemical resistance of the films and the like proposed in patent documents 3 to 6 is not sufficient.

Resin materials such as polymethyl methacrylate (PMMA) and Polycarbonate (PC) are often used as the base material constituting the interior and exterior of the vehicle. However, since these resin materials have low solvent resistance, alcohols which are difficult to deteriorate substrates and the like need to be used as a diluting solvent in coating compositions for forming a coating film or a cured film which is in contact with substrates made of these resin materials. However, the curable resin component to be blended in a general coating composition (resin composition) for forming a coating film or a cured film of a decorative film is not necessarily easily dissolved in an alcohol.

The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide an ionizing radiation curable coating composition which can form a cured film having excellent thermal stretchability (for example, 30% or more) and excellent solvent resistance and chemical resistance, and which can contain an alcohol as a diluting solvent. Another object of the present invention is to provide a decorative film and a decorative molded article obtained using the ionizing radiation-curable coating composition.

Means for solving the problems

That is, the present invention provides the following coating compositions.

[1] A coating composition of an ionizing radiation curing type, which comprises: a urethane (meth) acrylate oligomer (A1) having 6 or more (meth) acryloyl groups and a weight average molecular weight of 3000 to 50000; the aforementioned urethane (meth) acrylate oligomer (a1) is an organosilicon modified oligomer having: a structural unit (a) derived from a polyfunctional (meth) acrylate monomer having a hydroxyl group and 3 or more (meth) acryloyl groups, a structural unit (b) derived from an alcohol having a molecular weight of 100 or less and having 2 or more hydroxyl groups, a structural unit (c) derived from isophorone diisocyanate, and a structural unit (d) derived from a carbinol-modified polysiloxane, wherein the content of the structural unit (d) in the urethane (meth) acrylate oligomer (a1) is 0.1 to 10 mass% with respect to the total of the structural units (a) to (c), and the content of the urethane (meth) acrylate oligomer (a1) is 50 mass% or more based on the coating solid content.

[2] The coating composition according to the above [1], wherein the weight average molecular weight of the methanol-modified polysiloxane is 3000 or less.

[3] The coating composition according to the above [1] or [2], wherein the polyfunctional (meth) acrylate monomer is at least one of pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate.

[4] The coating composition according to any one of the above [1] to [3], wherein the alcohol is at least one of ethylene glycol and glycerol.

[5] The coating composition according to any one of the above [1] to [4], further comprising an inorganic filler having an average primary particle diameter of 1 to 100nm, wherein the content of the inorganic filler is 1 to 50% by mass based on the solid content of the coating material.

The present invention can provide a decorative film and a decorative molded article described below.

[6] A decorative film comprising: a film-like plastic substrate, and a cured film which is provided on at least one surface of the plastic substrate and is obtained by curing a coating film formed from the coating composition according to any one of the above [1] to [5 ].

[7] A decorative molded article comprising: a molded article body made of a resin, and a cured film which is provided on at least a part of a surface of the molded article body and is obtained by curing a coating film formed from the coating composition according to any one of the above items [1] to [5 ].

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide an ionizing radiation-curable coating composition which can form a cured film having excellent thermal stretchability (for example, 30% or more) and excellent solvent resistance and chemical resistance, and which can contain an alcohol as a diluting solvent. The present invention also provides a decorative film and a decorative molded article obtained using the ionizing radiation-curable coating composition.

Detailed Description

< coating composition >

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments below. The ionizing radiation-curable coating composition of the present invention contains: a urethane (meth) acrylate oligomer (A1) having 6 or more (meth) acryloyl groups and a weight average molecular weight of 3000 to 50000. The content of the urethane (meth) acrylate oligomer (a1) is 30% by mass or more based on the solid content of the coating material. The coating composition of the present invention will be described in detail below.

(urethane (meth) acrylate oligomer (A1))

The coating composition contains a urethane (meth) acrylate oligomer (a1) (hereinafter also referred to simply as "urethane acrylate oligomer") as a resin component. The urethane acrylate oligomer is a so-called silicone-modified oligomer having a structural unit (d) derived from a carbinol-modified polysiloxane in the molecular structure. In this way, the coating composition contains the silicone-modified oligomer embedded in the molecular structure thereof, not just the silicone component, and therefore, problems such as bleeding of the silicone component are unlikely to occur. Further, since the formed coating film or cured film can contain a silicone component as a water-repellent component, a coating composition capable of forming a coating film or cured film excellent in chemical resistance can be obtained. Further, since the coating composition contains a silicone-modified oligomer in which a silicone component is embedded in its molecular structure, it is expected that a coating film or a cured film having improved sliding properties and abrasion resistance can be formed.

The urethane acrylate oligomer is an oligomer having 6 or more (meth) acryloyl groups in its molecular structure. By using a urethane acrylate oligomer having 6 or more (meth) acryloyl groups, a coating composition capable of forming a cured film having excellent solvent resistance and chemical resistance can be obtained.

The weight average molecular weight of the urethane acrylate oligomer is 3000 to 50000, preferably 4000 to 40000. By using a urethane acrylate oligomer having a weight average molecular weight within the above range, a coating composition capable of forming a cured film having stretchability (for example, 30% or more) under heating and excellent solvent resistance and chemical resistance can be obtained. The weight average molecular weight in the present specification is a value in terms of polystyrene measured by Gel Permeation Chromatography (GPC).

The content of the urethane acrylate oligomer in the coating composition is 30% by mass or more, preferably 50 to 100% by mass, based on the solid content of the coating. When the content of the urethane acrylate oligomer based on the solid content of the coating material is too small, the solvent resistance and chemical resistance of the formed cured film are lowered, and when the cured films are brought into contact with each other, the bonding becomes easy, and the tack-free property is lowered.

[ structural Unit (a) ]

The urethane acrylate oligomer has: a structural unit (a) derived from a polyfunctional (meth) acrylate monomer having a hydroxyl group and 3 or more (meth) acryloyl groups. By having the structural unit (a), a urethane acrylate oligomer having 6 or more (meth) acryloyl groups can be produced. The polyfunctional (meth) acrylate monomer constituting the structural unit (a) is preferably at least one of pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate.

[ structural Unit (b) ]

The urethane acrylate oligomer has: a structural unit (b) derived from an alcohol having 2 or more hydroxyl groups and a molecular weight of 100 or less. The alcohol constituting the structural unit (b) is a so-called short-chain alcohol. By having the structural unit (b) derived from such a short-chain alcohol, a urethane acrylate oligomer having a structure in which the structural unit (c) derived from isophorone diisocyanate, which will be described later, is densely repeated and continuously formed can be obtained. The urethane acrylate oligomer having such a structure is easily dissolved in alcohols. Further, by using the urethane acrylate oligomer having such a structure, a coating composition capable of forming a cured film excellent in solvent resistance and chemical resistance can be obtained, and the tack-free chirality of the cured film can be improved. The alcohol constituting the structural unit (b) is preferably at least one of ethylene glycol and glycerol.

[ structural Unit (c) ]

The urethane acrylate oligomer has a structural unit (c) derived from isophorone diisocyanate. By using the urethane acrylate oligomer having the structural unit (c), a coating composition capable of forming a cured film excellent in solvent resistance and chemical resistance can be obtained. When an aliphatic polyisocyanate such as Hexamethylene Diisocyanate (HDI) is used instead of isophorone diisocyanate, which is an alicyclic polyisocyanate, the crystallinity of the urethane acrylate oligomer becomes too high, and the synthesis is easily difficult at first. In addition, when an aromatic polyisocyanate is used, the weather (light) -resistance of the cured film formed is lowered.

[ structural Unit (d) ]

The urethane acrylate oligomer has a structural unit (d) derived from a carbinol-modified polysiloxane. Examples of the methanol-modified polysiloxane include compounds represented by the following general formula (1).

In the general formula (1), R^a～R^jEach independently represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or-R^k-OH (wherein, R^kIs alkylene). Wherein R is^a～R^jAt least 1 of which is-R^k-OH. m and n each independently represent 0 or a positive integer (wherein m + n.gtoreq.1). In addition, R is^a～R^jMay be bonded to each other to form a ring structure.

As the methanol-modified polysiloxane, commercially available products, newly synthesized products, and the like can be used. From the viewpoint of compatibility, viscosity, and the like, the weight average molecular weight of the methanol-modified polysiloxane is preferably 10000 or less, and more preferably 3000 or less.

(solvent)

The coating composition may further contain a solvent such as an organic solvent. That is, the urethane acrylate oligomer can be used in a diluted state by dissolving it in an appropriate organic solvent. Examples of the organic solvent include esters such as ethyl acetate, propyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; hydrocarbons such as benzene, toluene, xylene, and n-hexane; alcohols such as ethanol, isopropanol, n-butanol, and propylene glycol monomethyl ether; glycol ethers such as propylene glycol monomethyl ether and butyl cellosolve. Among these, alcohols are preferable, and propylene glycol monomethyl ether is more preferable, in view of the coating of a substrate having low solvent resistance, the influence on members and the like in contact with a formed cured film, the mixing with other resin components, and the like.

(inorganic Filler)

The coating composition may be made to further contain an inorganic filler. By containing the inorganic filler, physical properties such as abrasion resistance of the cured film to be formed can be improved. As the inorganic filler, for example, fine particles of alumina, nano silica, or the like can be used. Among them, alumina fine particles are preferably used. From the viewpoint of dispersibility and transparency, the average primary particle diameter of the inorganic filler is preferably 1 to 100nm, and more preferably 50nm or less. The content of the inorganic filler in the coating composition is preferably 1 to 50% by mass based on the solid content of the coating. The "average primary particle diameter" in the present specification means a 50% cumulative value (D) of a volume-based particle diameter distribution₅₀). The particle size distribution of the particles can be measured using a laser diffraction particle size distribution measuring apparatus.

(other Components)

If necessary, the coating composition may further contain a curable resin component having an ethylenically unsaturated double bond such as a (meth) acrylate polymer, a (meth) acrylate oligomer, and a (meth) acrylate monomer, which have a different number of functional groups and a different structure from those of the urethane acrylate oligomer. In addition to the above-mentioned curable resin component, various curable components having an ethylenically unsaturated double bond may be contained. Examples of such a curable component include an acryl (meth) acrylate having an acrylic equivalent of 150g/eq or more, a urethane (meth) acrylate oligomer having a (meth) acryl group, a polyester (meth) acrylate oligomer, an epoxy (meth) acrylate oligomer, and a (meth) acrylate monomer.

The coating composition may contain a photopolymerization initiator. Examples of the photopolymerization initiator include 2, 2-dimethoxy-1, 2-diphenylethane-1-one, 1-cyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, and mixtures thereof, 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, 4-methylbenzophenone, and the like. A known curing accelerator and a photopolymerization initiator may be used in combination. The amount of the photopolymerization initiator is preferably 3 to 10 parts by mass per 100 parts by mass of the curable resin composition containing the urethane acrylate oligomer.

Various additives may be included in the coating composition. Examples of the additive include a silane coupling agent, a leveling agent, an antifoaming agent, an antioxidant, a thermoplastic resin, an antistatic agent, a wax, a heat stabilizer, a flame retardant, a deodorant, an ultraviolet absorber (UVA), a radical scavenger (HALS), and a surfactant. The inclusion of an ultraviolet absorber or a radical scavenger is preferable because the weather resistance of the cured film to be formed can be further improved. Further, the addition of a silicone surfactant or a fluorine surfactant is preferable because the solvent resistance and the stain resistance of the cured film formed can be improved.

< decorative film >

By using the coating composition, a decorative film suitable for decorating various molded articles such as vehicle interior and exterior trims can be obtained. That is, the decorative film of the present invention comprises: a film-like plastic substrate, and a cured film which is provided on at least one surface of the plastic substrate and is obtained by curing a coating film formed from the coating composition.

Examples of the plastic (resin) constituting the plastic substrate include polymethyl methacrylate (PMMA), Polycarbonate (PC), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), polyethylene terephthalate (PET), Triacetylcellulose (TAC), cycloolefin polymer (COP), and the like. Among them, PMMA and PC are preferable for decorative use of vehicle interior and exterior. The plastic substrate is also preferably a laminated film.

From the viewpoint of workability, processability, etc., the thickness of the film-like plastic substrate is preferably 25 to 500 μm.

For the purpose of improving the adhesion of the coating composition, the surface of the coating composition (surface on which the cured film is disposed) on which the plastic substrate is coated is preferably subjected to surface treatment. Examples of the surface treatment include surface roughening treatment such as primer treatment, sand blast treatment, and solvent treatment; oxidation treatment such as corona discharge treatment, chromic acid treatment, ozone/ultraviolet irradiation treatment, and the like. On the other hand, when the decorative film is used for in-mold transfer, it is preferable to release the surface of the plastic substrate with a melamine resin, a silicone component resin, a fluororesin or the like for the purpose of improving the releasability from the coating composition.

The decorative film can be produced by a conventionally known method. For example, the coating composition is applied to the surface of the plastic substrate by a known coating method such as roll coating, gravure coating, comma coating, knife coating, die coating, screen coating, or the like to form a coating film. Then, the formed coating film is irradiated with ultraviolet rays or electron beams at a predetermined dose to cure the coating film to form a cured film, whereby a decorative film can be obtained. As the device for irradiating ultraviolet rays and electron beams, known ultraviolet ray irradiation devices and electron beam irradiation devices such as xenon lamps, metal halide lamps, high-pressure mercury lamps, low-pressure mercury lamps, electrodeless lamps, LED lamps, xenon flash lamps, excimer lamps, and the like can be used.

The thickness of the coating film or the cured film may be set as appropriate depending on the application. Specifically, the thickness of the coating film or cured film is usually 100nm to 10 μm, preferably 3 to 5 μm. Further, a decorative film having an antireflection effect can be obtained by laminating and disposing a low refractive index layer having a thickness of about 100 nm.

< decorative molded article >

Various decorative molded articles can be obtained by using the coating composition and a decorative film produced by using the coating composition. That is, the decorative molded article of the present invention includes: a molded article body made of a resin, and a cured film which is provided on at least a part of a surface of the molded article body and is obtained by curing a coating film formed from the coating composition.

As described above, the coating composition of the present invention is a material capable of forming a cured film having excellent solvent resistance and chemical resistance while having excellent thermal stretchability. Therefore, a decorative molded article comprising a cured film obtained by curing a coating film formed from the coating composition has a cured film excellent in stretchability under heat, solvent resistance and chemical resistance on at least a part of the surface. Specific examples of the decorative molded article having such characteristics include vehicle interior and exterior, building material interior and exterior, home appliances, mobile applications, and the like.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "part(s)" and "%" are based on mass unless otherwise specified.

< production of urethane acrylate oligomer >

(urethane acrylate oligomer A)

Into a three-necked flask, 1696 parts of pentaerythritol triacrylate, 420 parts of ethylene glycol, 120 parts of methanol-modified polysiloxane (molecular weight 1000), 4 parts of dibutyltin laurate, 8 parts of 2, 6-tert-butyl-4-methylphenol (BHT), and 4000 parts of propyl acetate were charged. After uniformly stirring, 1883 parts of isophorone diisocyanate were added while controlling the temperature to 60 ℃. Thereafter, the reaction was terminated by stirring at 70 ℃ for 15 hours to obtain a solution (solid content: 50%) of urethane acrylate oligomer a (6-functional) having a weight average molecular weight of 5000. The content of the structural unit (d) in the obtained urethane acrylate oligomer a was 3.0% with respect to the total of the structural units (a) to (c). The obtained urethane acrylate oligomer a is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer B)

Into a three-necked flask, 2328 parts of pentaerythritol triacrylate, 262 parts of ethylene glycol, 120 parts of methanol-modified polysiloxane (molecular weight 1000), 4 parts of dibutyltin laurate, 8 parts of BHT, and 4000 parts of propyl acetate were charged. After uniformly stirring, 1410 parts of isophorone diisocyanate were added while controlling the temperature to 60 ℃. Thereafter, the reaction was terminated by stirring at 70 ℃ for 15 hours to obtain a solution (solid content: 50%) of urethane acrylate oligomer B (6-functional) having a weight average molecular weight of 3000. The content of the structural unit (d) in the obtained urethane acrylate oligomer B was 3.0% with respect to the total of the structural units (a) to (c). The obtained urethane acrylate oligomer B is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer C)

Into a three-necked flask, 1163 parts of pentaerythritol triacrylate, 393 parts of ethylene glycol, 96 parts of methanol-modified polysiloxane (molecular weight 1000), 4 parts of dibutyltin laurate, 8 parts of BHT, and 4800 parts of propyl acetate were charged. After uniformly stirring, 1643 parts of isophorone diisocyanate was added while controlling to 60 ℃. Thereafter, the reaction was terminated by stirring at 70 ℃ for 15 hours to obtain a solution (solid content: 40%) of urethane acrylate oligomer C (6-functional) having a weight average molecular weight of 7000. The content of the structural unit (d) in the obtained urethane acrylate oligomer C was 3.0% with respect to the total of the structural units (a) to (C). The obtained urethane acrylate oligomer C is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer D)

A solution (solid content: 40%) of urethane acrylate oligomer D (10 functional group) having a weight average molecular weight of 6000 was obtained in the same manner as in the case of the urethane acrylate oligomer a described above, except that dipentaerythritol pentaacrylate was used instead of pentaerythritol triacrylate. The content of the structural unit (D) in the obtained urethane acrylate oligomer D was 3.0% with respect to the total of the structural units (a) to (c). The obtained urethane acrylate oligomer D is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer E)

Into a three-necked flask, 1284 parts of pentaerythritol triacrylate, 290 parts of ethylene glycol, 72 parts of glycerol, 96 parts of methanol-modified polysiloxane (molecular weight 1000), 4 parts of dibutyltin laurate, 8 parts of BHT, and 4800 parts of propyl acetate were charged. After uniformly stirring, 1555 parts of isophorone diisocyanate was added while controlling the temperature to 60 ℃. Thereafter, the reaction mixture was stirred at 70 ℃ for 15 hours to complete the reaction, thereby obtaining a urethane acrylate oligomer E (9-functional) solution (solid content: 40%) having a weight average molecular weight of 37000. The content of the structural unit (d) in the obtained urethane acrylate oligomer E was 3.1% based on the total of the structural units (a) to (c). The obtained urethane acrylate oligomer E is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer F)

A solution (solid content 40%) of urethane acrylate oligomer F (6-functional) having a weight average molecular weight of 7000 was obtained in the same manner as in the case of the aforementioned urethane acrylate oligomer C, except that the methanol-modified polysiloxane was not used. The urethane acrylate oligomer F obtained does not contain the structural unit (d). The obtained urethane acrylate oligomer F is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer G)

A solution (solid content 40%) of urethane acrylate oligomer G (10 functional group) having a weight average molecular weight of 6000 was obtained in the same manner as in the case of the urethane acrylate oligomer D described above, except that the carbinol-modified polysiloxane was not used. The urethane acrylate oligomer G obtained does not contain the structural unit (d). The obtained urethane acrylate oligomer G is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer H)

Into a three-necked flask were charged 633 parts of hydroxyethyl acrylate, 615 parts of ethylene glycol, 120 parts of methanol-modified polysiloxane (molecular weight 1000), 4 parts of dibutyltin laurate, 8 parts of BHT, and 4000 parts of propyl acetate. After uniformly stirring, 2751 parts of isophorone diisocyanate was added while controlling the temperature to 60 ℃. Thereafter, the reaction was terminated by stirring at 70 ℃ for 15 hours to obtain a solution (solid content: 50%) of urethane acrylate oligomer H (2-functional) having a weight average molecular weight of 3000. The content of the structural unit (d) in the obtained urethane acrylate oligomer H was 3.0% with respect to the total of the structural units (a) to (c). The urethane acrylate oligomer H obtained is soluble in alcohols such as propylene glycol monomethyl ether.

(urethane acrylate oligomer I)

Into a three-necked flask, 1454 parts of pentaerythritol triacrylate, 492 parts of ethylene glycol, 120 parts of methanol-modified polysiloxane (molecular weight: 1000), 4 parts of dibutyltin laurate, 8 parts of BHT, and 4000 parts of acryloylmorpholine (ACMO, manufactured by KJ chemical). After uniformly stirring, 2054 parts of isophorone diisocyanate was added while controlling the temperature to 60 ℃. Thereafter, the reaction was terminated by stirring at 70 ℃ for 15 hours to obtain a solution of a urethane acrylate oligomer I (6-functional) having a weight-average molecular weight of 7700 (solid content 100% (solvent-free)). The urethane acrylate oligomer I contained 50% of a urethane acrylate oligomer C. The content of the structural unit (d) in the obtained urethane acrylate oligomer I was 3.0% with respect to the total of the structural units (a) to (c). The obtained urethane acrylate oligomer I is soluble in alcohols such as propylene glycol monomethyl ether.

< preparation of coating composition and production of decorative film (test piece) >

(example 1)

A solution of urethane acrylate oligomer A (solid content: 50%) was mixed with 100 parts of a photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, trade name: Irgacure184, manufactured by BYK Japan KK.) and 5 parts of an alumina fine particle dispersion (trade name: NANOBYK-3610, manufactured by BYK Japan KK., solid content: 37%) in terms of alumina content. Propylene Glycol Monomethyl Ether (PGME) was added thereto and diluted to obtain a coating composition having a coating solid content of 25%. The obtained coating composition was applied to (i) a 25 μm thick easy-to-mold PET film (manufactured by Dupont Tekken Co., Ltd.) and (ii) a 75 μm thick PMMA film (manufactured by Mitsubishi chemical Co., Ltd.) using a wire bar so that the film thickness after drying became 3 μm. After drying at 100 ℃ for 40 seconds, the resultant was dried at a high pressure mercury lamp of 80W/cm at a rate of about 300mJ/cm²And (3) curing the mixture to form a cured film, thereby obtaining 2 kinds of test pieces (decorative films).

(example 2)

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that the solution of the urethane acrylate oligomer B was used instead of the solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

(example 3)

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that the solution of the urethane acrylate oligomer C was used instead of the solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

(example 4)

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that a solution of the urethane acrylate oligomer D was used instead of the solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

(example 5)

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that the solution of the urethane acrylate oligomer E was used instead of the solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

(example 6)

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 3 except that a UV reactive silicone additive (trade name "BYK-UV 3500", manufactured by BYK Japan KK.) was further used in an amount of 0.2% in terms of solid content relative to the urethane acrylate oligomer C. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

(reference example 7)

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that a solution containing urethane acrylate oligomer I and ACMO (urethane acrylate oligomer I: ACMO: 65: 35 (mass ratio)) was used instead of the solution of urethane acrylate oligomer a. The content of the urethane acrylate oligomer C in the coating solid content of the obtained coating composition was 30% or more. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 1

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that a solution of the urethane acrylate oligomer F was used instead of the solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 2

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that a solution of the urethane acrylate oligomer G was used instead of a solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 3

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that a solution of the urethane acrylate oligomer H was used instead of the solution of the urethane acrylate oligomer a. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 4

A coating composition containing 25% of coating solid content was obtained in the same manner as in example 1, except that a solution of acryloyl acrylate (double bond equivalent weight 260g/eq, weight average molecular weight 30000) was used instead of the solution of urethane acrylate oligomer A. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 5

A coating composition containing 25% of coating solid content was obtained in the same manner as in example 1, except that a solution of acryloyl acrylate (double bond equivalent weight 830g/eq, weight average molecular weight 30000) was used instead of the solution of urethane acrylate oligomer A. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 6

A coating composition having a coating solid content of 25% was obtained in the same manner as in comparative example 1 except that a UV reactive silicone additive (trade name "BYK-UV 3500", manufactured by BYK Japan KK.) was further used in an amount of 0.2% in terms of solid content relative to the urethane acrylate oligomer F. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

Comparative example 7

A coating composition having a coating solid content of 25% was obtained in the same manner as in example 1, except that a solution containing urethane acrylate oligomer I and ACMO (urethane acrylate oligomer I: ACMO: 50 (mass ratio)) was used instead of the solution of urethane acrylate oligomer a. The coating composition obtained had a content of urethane acrylate oligomer C in the coating solid content of less than 30%. Then, 2 kinds of test pieces (decorative films) were obtained in the same manner as in example 1, except that the obtained coating composition was used.

< evaluation >

(1) Appearance of the product

The appearance (color tone/compatibility) of the cured film was visually observed and evaluated in 5 stages (poor 1 → · · · · · · · → · · · · → · · · · · → · · · → · · → · · · → · · · · · · · → · · → · · · · → · · · · · · · · 5 good) by which was good) by a), which was evaluated, a), the appearance of the cured films were evaluated, a, 5-good), and the appearance (color tone/compatibility). The results are shown in Table 1.

(2) Non-sticking to the chirality

The cured films of 2 test pieces were bonded to each other so as to be in contact with each other, and the test pieces were left under a load of 10kg for 30 seconds. Then, the tack-free chirality was evaluated according to the evaluation criteria shown below. The results are shown in Table 1.

O: there is no joint.

And (delta): slight bonding occurred during peeling, but no abnormality occurred in the contact surface.

X: failure to peel off or abnormality in the contact surface.

(3) Extensibility by heating

A tensile test was carried out using a tensile tester (trade name "AGS-X", manufactured by Shimadzu corporation) to evaluate the thermal stretchability of the cured film. Specifically, first, a test piece (width 10 mm. times. length 110mm) made of an easily moldable PET film was set to a tensile tester with a distance between jigs of 60 mm. Then, the test piece was pulled at a speed of 50 mm/min under a temperature condition of 120 ℃ to measure the elongation (degree of thermal expansion (%)) of the cured film at the time point of crack generation as an index of thermal extensibility. The elongation at the time point when the distance between the jigs became 120mm was defined as "elongation at heating ═ 100%". The measurement results of the degree of elongation (%) under heating are shown in Table 1.

(4) Solvent resistance

Using a dropper, 2 drops of xylene were dropped on the surface of the cured film of a test piece made of a PMMA thin film, and then the cured film was left at room temperature for 30 minutes. Then, the surface of the cured film was wiped with a cloth and visually observed to evaluate the solvent resistance in 5 stages (Difference 1 → 5 Excellent). The results are shown in Table 1.

(5) Chemical resistance

The surface of the cured film of a test piece made of a PMMA film was wiped with a cloth 20 times in a reciprocating manner under a load of 1 kg. Then, a cosmetic for hand (trade name "Neutrogena (registered trademark)", product of qiangsheng corporation) was applied to the wiped surface of the cured film with a cotton swab so as to draw a circle having a diameter of 30 mm. After being left in a drier at 80 ℃ for 6 hours, the surface of the cured film was wiped with a cloth and visually observed, and chemical resistance was evaluated in 5 stages (Difference 1 → · · → 5 Excellent). The results are shown in Table 1.

[ Table 1]

When examples 1 to 4 were compared with comparative examples 1 and 2, it was found that examples 1 to 4 were excellent in chemical resistance. In particular, the greater the molecular weight of the urethane acrylate oligomer, the more excellent the chemical resistance. By using a urethane acrylate oligomer having a structure in which an isophorone cyclic structure is continuously repeated, the thermal stretchability and chemical resistance of a cured film are improved, and since a urethane acrylate oligomer that is a silicone-modified oligomer is used, it is considered that a drug (cosmetic) does not penetrate into a substrate.

From the evaluation results of examples 1 to 3, it was found that the higher the molecular weight of the urethane acrylate oligomer, the higher the elongation at heating, but the slightly lower the chemical resistance. However, since a urethane acrylate oligomer as a silicone-modified oligomer is used, the chemical resistance is not greatly reduced. Further, from the evaluation results of example 5, it was found that when a urethane acrylate oligomer having a structural unit derived from glycerin is used, chemical resistance is not lowered even if the molecular weight is large. This is considered to be because a urethane acrylate oligomer having a structure in which the number of functional groups (acryloyl groups) is large and the isophorone cyclic structure is more densely repeated is used.

From the evaluation results of comparative example 3, it was found that when a urethane acrylate oligomer having a small number of functional groups (acryloyl groups) was used, sufficient thermal stretchability was exhibited, while solvent resistance and chemical resistance were remarkably reduced.

When example 3 and example 6 were compared, it was found that the solvent resistance was improved by using the silicone-based additive. However, when example 6 and comparative example 6 were compared, it was found that the use of the UV-reactive silicone additive instead of the urethane acrylate oligomer as the silicone-modified oligomer reduced the chemical resistance. In comparative example 6, it is considered that in the evaluation of chemical resistance, the surface of the cured film was wiped to wipe off the silicone-based additive on the surface of the cured film, and the sliding was reduced and the damage was slight, so that the chemical resistance was reduced.

When reference example 7 and comparative example 7 were compared, it was found that by containing a certain amount or more of the urethane acrylate oligomer, the coating composition was sufficiently cured to exhibit effective solvent resistance and chemical resistance.

Industrial applicability

The coating composition of the present invention is useful as a material for producing a decorative film or a decorative molded article.