JP7024927B2 - Polycarbonate modified acrylic resin, paint and plastic molded products painted with the paint - Google Patents

Description

The present invention relates to a polycarbonate-modified acrylic resin, a paint, and a plastic molded product coated with the paint.

Conventionally, a polycarbonate-modified acrylic resin obtained by reacting an unsaturated monomer in the presence of a polyol has been proposed, and it is known that the cured coating film has excellent adhesion to a substrate, mechanical properties, and the like. (See, for example, Patent Document 1).

However, although the coating film obtained from this polycarbonate-modified acrylic resin has excellent scratch resistance and the like, it has a drawback that the fragrance resistance required for plastic paints and the like is insufficient in recent years. Therefore, there has been a demand for a material that can impart fragrance resistance in addition to the conventional adhesiveness.

International Publication No. WO2015 / 045562

The problem to be solved by the present invention is a polycarbonate-modified acrylic resin, a coating material, and a coating material, which have high adhesion to a plastic substrate and can obtain a coating film having excellent water adhesion resistance and fragrance resistance. It is to provide a plastic molded product that has been made.

As a result of diligent research to solve the above problems, the present inventors have made polycarbonate which is a reaction product of a specific polycarbonate diol and an unsaturated monomer mixture containing a specific unsaturated monomer as an essential component. We have found that by using a modified acrylic resin, it is possible to obtain a coating film having high adhesion to a plastic substrate and excellent water adhesion resistance and fragrance resistance, and completed the invention.

That is, the present invention comprises a polycarbonate diol (A) made from 1,5-pentanediol and 1,6-hexanediol as raw materials, a methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, and a non-polycarbonate having a carboxyl group. Polycarbonate modification which is a reaction product with an unsaturated monomer mixture (B) containing a saturated monomer (b2) and an unsaturated monomer (b3) having an alkyl group having 10 to 24 carbon atoms as an essential component. In the acrylic resin, the mass ratio of methyl methacrylate in the unsaturated monomer mixture (B) is 30 to 95% by mass, and the mass ratio of the unsaturated monomer (b2) is less than 10% by mass. The present invention relates to a polycarbonate-modified acrylic resin, a paint, and a plastic molded product coated with the paint.

The polycarbonate-modified acrylic resin of the present invention is useful for paints because it has high adhesion to a plastic base material and can obtain a coating film having excellent water adhesion resistance and fragrance resistance. Can be painted on molded products. Therefore, the polycarbonate-modified acrylic resin of the present invention is used as a housing for electronic devices such as mobile phones, smartphones, tablet terminals, personal computers, digital cameras, and game machines; and housings for home appliances such as televisions, refrigerators, washing machines, and air conditioners; It can be suitably used as a paint for painting various articles such as interior materials of various vehicles such as automobiles and railway vehicles.

The polycarbonate-modified acrylic resin of the present invention contains a polycarbonate diol (A) made from 1,5-pentanediol and 1,6-hexanediol, a methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, and a carboxyl group. A reaction product with an unsaturated monomer mixture (B) containing an unsaturated monomer (b2) having an unsaturated monomer (b2) and an unsaturated monomer (b3) having an alkyl group having 10 to 24 carbon atoms as essential components. In a certain polycarbonate-modified acrylic resin, the mass ratio of methyl methacrylate in the unsaturated monomer mixture (B) is 30 to 95% by mass, and the mass ratio of the unsaturated monomer (b2) is 10. It is less than% by mass.

First, the polycarbonate diol (A) will be described. The polycarbonate diol (A) is a polycarbonate diol made from 1,5-pentanediol and 1,6-hexanediol, and is, for example, 1,5-pentanediol and 1,6-hexanediol, and a carbonic acid ester or a carbonic acid ester. It is obtained by reaction with phosgene.

Next, the unsaturated monomer mixture (B) will be described. This unsaturated monomer mixture (B) contains methyl methacrylate, an unsaturated monomer (b1) having a hydroxyl group, an unsaturated monomer (b2) having a carboxyl group, and an alkyl group having 10 to 24 carbon atoms. It contains the unsaturated monomer (b3) having an essential component, the mass ratio of methyl methacrylate is 30 to 95% by mass, and the mass ratio of the unsaturated monomer (b2) is less than 10% by mass. Is what it is.

Examples of the unsaturated monomer (b1) having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxy-n-butyl (meth) acrylate, and 2-hydroxy. Propyl (meth) acrylate, 2-hydroxy-n-butyl (meth) acrylate, 3-hydroxy-n-butyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, glycerin mono (meth) acrylate, Polyoxyethylene mono (meth) acrylate, polyoxypropylene mono (meth) acrylate, polyoxybutylene mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2 -Hydroxyethyl phthalate, polycaprolactone-modified hydroxyethyl mono (meth) acrylate and the like can be mentioned. Among these, 2-hydroxyethyl (meth) acrylate is preferable because the appearance of the obtained coating film, water adhesion resistance, and fragrance resistance are excellent. These unsaturated monomers (b1) can be used alone or in combination of two or more.

In the present invention, "(meth) acrylic acid" means one or both of methacrylic acid and acrylic acid, and "(meth) acrylate" means one or both of methacrylate and acrylate, and "(meth) acrylate". ) Acryloyl group means one or both of a methacryloyl group and an acryloyl group.

Examples of the unsaturated monomer (b2) having a carboxyl group include (meth) acrylic acid, crotonic acid, β-carboxyethyl (meth) acrylate, ω-carboxy-polycaprolactone mono (meth) acrylate, and 2-. Unsaturated monocarboxylic acids such as (meth) acryloyloxyethyl succinate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, or these unsaturated dicarboxylic acids. Examples include half ester. Among these, (meth) acrylic acid is preferable because the obtained coating film has more excellent fragrance resistance. In addition, these unsaturated monomers (b2) can be used alone or in combination of two or more.

Examples of the unsaturated monomer (b3) having an alkyl group having 10 to 24 carbon atoms include isobornyl (meth) acrylate, 4-tert-butylcyclohexyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. , Decyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate and the like. Since the fragrance resistance of the above is more excellent, an unsaturated monomer having an alkyl group having 10 to 18 carbon atoms is preferable. Further, these unsaturated monomers (b3) can be used alone or in combination of two or more.

Further, as the components of the unsaturated monomer mixture (B), the above-mentioned essential raw materials such as methyl methacrylate, unsaturated monomer (b1), unsaturated monomer (b2), and unsaturated monomer (b) Other monomers (b4) other than b3) may be used. Examples of the other monomer (b4) include methyl acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl ( Meta) acrylate, nonyl (meth) acrylate, benzyl (meth) acrylate; acrylamide, N, N-dimethyl (meth) acrylamide, (meth) acrylonitrile, 3- (meth) acryloyloxypropyltrimethoxysilane, N, N-dimethyl Aminoethyl (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, glycidyl (meth) acrylate, vinyl acetate, styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, ethyleneglycoldiacrylate, etc. Examples include diacrylate compounds. In addition, these unsaturated monomers can be used alone or in combination of two or more.

The unsaturated monomer mixture (B) has a mass ratio of methyl methacrylate of 30 to 95% by mass, but since the water adhesion resistance and fragrance resistance of the obtained coating film are further improved, 55 to 90 The mass% is preferable, and 75 to 90% by mass is more preferable.

The unsaturated monomer mixture (B) has a mass ratio of the unsaturated monomer (b2) of less than 10% by mass, but the fragrance resistance of the obtained coating film is further improved. The range of -8% by mass is preferable, and the range of 2 to 6% by mass is more preferable.

The unsaturated monomer mixture (B) contains the unsaturated monomer (b1) and the unsaturated monomer (b3) as essential components in addition to the methyl methacrylate and the unsaturated monomer (b2). Although it is contained, the mass ratio of the unsaturated monomer (b1) is in the range of 1 to 40% by mass because the obtained coating film has excellent fragrance resistance, and the unsaturated monomer is contained. The mass ratio of (b3) is preferably in the range of 1 to 30% by mass, the mass ratio of the unsaturated monomer (b1) is in the range of 3 to 30% by mass, and the unsaturated monomer (b1) is in the range of 3 to 30% by mass. It is more preferable that the mass ratio of b3) is in the range of 3 to 15 mass%.

Further, the glass transition temperature (hereinafter, abbreviated as "design Tg") calculated by the FOX formula of the unsaturated monomer mixture (B) improves the chemical resistance of the obtained coating film. , 60-110 ° C. is preferable.

In the present invention, the glass transition temperature calculated by the FOX equation is defined as the glass transition temperature.
FOX formula: 1 / Tg = W1 / Tg1 + W2 / Tg2 + ...
(Tg: glass transition temperature to be obtained, W1: weight fraction of component 1, Tg1: glass transition temperature of homopolymer of component 1)
It was calculated according to the above. The value of the glass transition temperature of the homopolymer of each component is determined by Polymer Handbook (4th Edition) J. Mol. Brandrup, E.I. H. Immunogut, E.I. A. The values described by Grulke (Wiley Interscience) were used.

As a method for obtaining the polycarbonate-modified acrylic resin of the present invention, a method of radically polymerizing the unsaturated monomer mixture (B) in the presence of the polycarbonate diol (A) and a solvent is preferable because it is simple.

The above-mentioned radical polymerization method is a method in which each monomer as a raw material is dissolved in a solvent and a polymerization reaction is carried out in the presence of a polymerization initiator. Examples of the solvent that can be used in this case include aromatic hydrocarbon compounds such as toluene and xylene; alicyclic hydrocarbon compounds such as cyclohexane, methylcyclohexane and ethylcyclohexane; acetone, methylethylketone, methylisobutylketone and cyclohexanone. Such as ketone compounds; ester compounds such as ethyl acetate, n-butyl acetate, isobutyl acetate, propylene glycol monomethyl ether acetate; alcohol compounds such as n-butanol, isopropyl alcohol, cyclohexanol; ethylene glycol monobutyl ether, propylene glycol monomethyl ether and the like. Glycol compounds; Examples thereof include aliphatic hydrocarbon compounds such as heptane, hexane, octane and mineral tarpen.

Examples of the polymerization initiator include ketone peroxide compounds such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (tert-butylperoxy) -3, 3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, 2,2-bis (4,4-di) tert-Butylperoxycyclohexyl) propane, 2,2-bis (4,4-ditert-amylperoxycyclohexyl) propane, 2,2-bis (4,4-ditert-hexylperoxycyclohexyl) propane, 2, Peroxyketal compounds such as 2-bis (4,4-ditert-octylperoxycyclohexyl) propane, 2,2-bis (4,54-dicumylperoxycyclohexyl) propane; cumenehydroperoxide, 2, Hydroperoxide compounds such as 5-dimethylhexane-2,5-dihydroperoxide; 1,3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di ( Dialkyl peroxide compounds such as tert-butylperoxy) hexane, diisopropylbenzene peroxide, tert-butyl cumyl peroxide, tert-butyl peroxide; decanoyle peroxide, lauroyl peroxide, benzoyl peroxide, 2,4- Diacyl peroxide compounds such as dichlorobenzoyl peroxide; peroxycarbonate compounds such as bis (tert-butylcyclohexyl) peroxydicarbonate; tert-butylperoxy-2-ethylhexanoate, tert-butylperoxybenzoate, 2 , 5-Dimethyl-2,5-di (benzoylperoxy) Organic peroxides such as peroxyester compounds such as hexane, 2,2'-azobis isobutyronitrile, 2,2'-azobis (2) Examples thereof include azo compounds such as -methyl) butyronitrile and 1,1'-azobis (cyclohexane-1-carbonitrile).

Further, the mass ratio [(A) / (B)] of the polycarbonate diol (A) and the unsaturated monomer mixture (B) has higher water adhesion resistance and fragrance resistance of the obtained coating film. From the viewpoint of improvement, the range of 2/98 to 80/20 is preferable, the range of 3/97 to 60/40 is preferable, and the range of 4/96 to 40/60 is more preferable.

The hydroxyl value of the polycarbonate-modified acrylic resin of the present invention is preferably in the range of 20 to 150, more preferably in the range of 60 to 130, because the fragrance resistance of the obtained coating film is further improved.

The weight average molecular weight (Mw) of the polycarbonate-modified acrylic resin of the present invention is preferably in the range of 2,000 to 50,000 because the water adhesion resistance and fragrance resistance of the obtained coating film are further improved. The range of 000 to 30,000 is more preferable. Here, the weight average molecular weight (Mw) is a value converted into polystyrene based on gel permeation chromatography (hereinafter, abbreviated as “GPC”) measurement.

The paint of the present invention contains the polycarbonate-modified acrylic resin of the present invention, but it preferably contains a curing agent (C) because the physical properties of the obtained coating film are further improved.

Examples of the curing agent (C) include polyisocyanate compounds and amino resins, but polyisocyanate compounds are preferable because the obtained coating film is excellent in water adhesion resistance and fragrance resistance. Further, these curing agents (C) can be used alone or in combination of two or more.

Examples of the polyisocyanate compound include aromatic diisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, m-xylylene diisocyanate, and m-phenylenebis (dimethylmethylene) diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, and 1,3-bis. (Isocyanatomethyl) aliphatic or fats such as cyclohexane, 2-methyl-1,3-diisocyanatocyclohexane, 2-methyl-1,5-diisocyanatocyclohexane, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, etc. Examples thereof include cyclic diisocyanate compounds.

Further, as the polyisocyanate compound, a prepolymer having an isocyanate group obtained by subjecting the above diisocyanate compound to an addition reaction with a polyhydric alcohol; a compound having an isocyanurate ring obtained by cyclizing and triquantizing the above diisocyanate compound; Polyisocyanate compound having urea bond or buretto bond obtained by reacting the above diisocyanate compound with water; 2-isocyanatoethyl (meth) acrylate, 3-isopropenyl-α, α-dimethylbenzylisocyanate, (meth) acryloyl A homopolymer of an acrylic monomer having an isocyanate group such as isocyanate; the acrylic monomer having an isocyanate group and other acrylic monomers, vinyl ester compounds, vinyl ether compounds, aromatic vinyl monomers, fluoroolefins. A copolymer having an isocyanate group obtained by copolymerizing with a monomer such as the above can also be used.

The above polyisocyanate compound may be used alone or in combination of two or more.

When the curing agent (C) is a polyisocyanate compound, a high-strength coating film can be obtained. Therefore, the isocyanate group in the polyisocyanate compound and the hydroxyl group in the polycarbonate-modified acrylic resin of the present invention are used. The equivalent ratio (isocyanate group / hydroxyl group) is preferably in the range of 0.5 to 2.0, more preferably in the range of 0.7 to 1.3.

The above urethanization reaction can also be carried out in the presence of a urethanization catalyst in order to accelerate the progress of the reaction. Examples of the urethanization catalyst include amine compounds such as triethylamine, dibutyltin dioctate, dibutyltin dilaurate, dioctyltin dilaurate, octyltintrilaurate, dioctyltin dineodecanete, dibutyltin diacetate, dioctyltin diacetate, and tin dioctylate. Examples thereof include organotin compounds and organometal compounds such as zinc octylate (zinc 2-ethylhexanoate).

The paint of the present invention contains the polycarbonate-modified acrylic resin of the present invention and the curing agent (C), but other formulations include a solvent, a defoaming agent, a viscosity modifier, a light-resistant stabilizer, and a weather-resistant stabilizer. , Heat-resistant stabilizers, ultraviolet absorbers, antioxidants, leveling agents, pigment dispersants and the like can be used. Further, pigments such as titanium oxide, calcium carbonate, aluminum powder, copper powder, mica powder, iron oxide, carbon black, phthalocyanine blue, toluidine red, perylene, quinacridone, and benzidine yellow can also be used.

Since the paint of the present invention has high adhesion to a plastic base material, it can be suitably used as a paint for painting various plastic molded products, but as a plastic molded product to which the paint of the present invention can be painted. Is the housing of electronic devices such as mobile phones, smartphones, tablet terminals, personal computers, digital cameras, and game machines; the housing of home appliances such as TVs, refrigerators, washing machines, and air conditioners; Examples include interior materials.

Examples of the method for applying the paint of the present invention include spray, applicator, bar coater, gravure coater, roll coater, comma coater, knife coater, air knife coater, curtain coater, kiss coater, shower coater, wheeler coater, spin coater, dipping, and the like. Methods such as screen printing can be mentioned. Further, as a method of forming a coating film after painting, a method of drying in a range of room temperature to 120 ° C. can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The hydroxyl value of the polycarbonate-modified acrylic resin of the present invention was measured according to the JIS test method K 0070-1992. The weight average molecular weight (Mw) is measured under the following GPC measurement conditions.

[GPC measurement conditions]
Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (Differential Refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection volume: 100 μL (sample concentration 4 mg / mL tetrahydrofuran solution)
Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

(Polystyrene monodisperse)
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

(Example 1: Synthesis of polycarbonate-modified acrylic resin (1))
Polycarbonate diol made from 1,5-pentanediol and 1,6-hexanediol ("Duranol T5650J" manufactured by Asahi Kasei Chemicals Co., Ltd., hydroxyl value) in a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer. 139.5, number average molecular weight 800; hereinafter abbreviated as "polycarbonate diol (A-1)"), 50 parts by mass and 500 parts by mass of propylene glycol monomethyl ether acetate were added, and the internal temperature was raised to 120 ° C. Then, 770 parts by mass of methyl methacrylate, 50 parts by mass of lauryl methacrylate, 100 parts by mass of 2-hydroxyethyl methacrylate, 30 parts by mass of methacrylic acid, 200 parts by mass of propylene glycol monomethyl ether acetate, and tert-butylperoxy 2-ethylhexanoate. 40 parts by weight of the mixture was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 5/95, weight. A solution of the polycarbonate-modified acrylic resin (1) having an average molecular weight of 13,000 was obtained.

(Example 2: Synthesis of polycarbonate-modified acrylic resin (2))
To a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 50 parts by mass of polycarbonate diol (A-1) and 500 parts by mass of propylene glycol monomethyl ether acetate were added, and the internal temperature was raised to 120 ° C. Then, 770 parts by mass of methyl methacrylate, 50 parts by mass of stearyl methacrylate, 100 parts by mass of 2-hydroxyethyl acrylate, 30 parts by mass of methacrylic acid, 200 parts by mass of propylene glycol monomethyl ether acetate, and tert-butylperoxy 2-ethylhexanoate. 40 parts by weight of the mixture was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 5/95, weight. A solution of a polycarbonate-modified acrylic resin (2) having an average molecular weight of 13,000 was obtained.

(Example 3: Synthesis of polycarbonate-modified acrylic resin (3))
To a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 50 parts by mass of polycarbonate diol (A-1) and 500 parts by mass of propylene glycol monomethyl ether acetate were added, and the internal temperature was raised to 120 ° C. Then, 770 parts by mass of methyl methacrylate, 50 parts by mass of isobornyl methacrylate, 100 parts by mass of 2-hydroxyethyl acrylate, 30 parts by mass of methacrylic acid, 200 parts by mass of propylene glycol monomethyl ether acetate, and tert-butylperoxy 2-ethylhexa. The mixture of 40 parts by mass of Noate was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 5/95, weight. A solution of a polycarbonate-modified acrylic resin (3) having an average molecular weight of 13,000 was obtained.

(Example 4: Synthesis of polycarbonate-modified acrylic resin (4))
To a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 300 parts by mass of polycarbonate diol (A-1) and 500 parts by mass of propylene glycol monomethyl ether acetate were added, and the internal temperature was raised to 120 ° C. Then, 500 parts by mass of methyl methacrylate, 50 parts by mass of isobornyl methacrylate, 100 parts by mass of 2-hydroxyethyl acrylate, 50 parts by mass of methacrylic acid, 200 parts by mass of propylene glycol monomethyl ether acetate, and tert-butylperoxy 2-ethylhexa. The mixture of 40 parts by mass of Noate was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 30/70, weight. A solution of a polycarbonate-modified acrylic resin (4) having an average molecular weight of 14,600 was obtained.

(Example 5: Synthesis of polycarbonate-modified acrylic resin (5))
To a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 50 parts by mass of polycarbonate diol (A-1) and 500 parts by mass of propylene glycol monomethyl ether acetate were added, and the internal temperature was raised to 120 ° C. Then, 770 parts by mass of methyl methacrylate, 80 parts by mass of isobornyl methacrylate, 100 parts by mass of 2-hydroxyethyl acrylate, 200 parts by mass of propylene glycol monomethyl ether acetate, and 40 parts by mass of tert-butylperoxy2-ethylhexanoate. The mixture (acrylic portion design Tg ° C.) was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 5/95, weight. A solution of a polycarbonate-modified acrylic resin (5) having an average molecular weight of 13,000 was obtained.

(Comparative Example 1: Synthesis of Comparative Resin (R1))
To a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 500 parts by mass of propylene glycol monomethyl ether acetate was added, and the internal temperature was raised to 120 ° C. Then, 770 parts by mass of methyl methacrylate, 50 parts by mass of isobornyl methacrylate, 150 parts by mass of 2-hydroxyethyl acrylate, 30 parts by mass of methacrylic acid, 100 parts by mass of propylene glycol monomethyl ether acetate, and tert-butylperoxy 2-ethylhexa. The mixture of 40 parts by mass of Noate was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 0/100, weight. A solution of the comparative resin (R1) having an average molecular weight of 12,600 was obtained.

(Comparative Example 2: Synthesis of Comparative Resin (R2))
To a flask equipped with a cooling tube, a thermometer, a dropping funnel, and a stirrer, 50 parts by mass of polycarbonate diol (A-1) and 500 parts by mass of propylene glycol monomethyl ether acetate were added, and the internal temperature was raised to 120 ° C. Then, 750 parts by mass of methyl methacrylate, 20 parts by mass of isobornyl methacrylate, 70 parts by mass of 2-hydroxyethyl acrylate, 110 parts by mass of methacrylic acid, 100 parts by mass of propylene glycol monomethyl ether acetate, and tert-butylperoxy 2-ethylhexa. The mixture of 40 parts by mass of Noate was added dropwise over 5 hours. After the reaction was continued at the same temperature for 17 hours after the completion of the dropping, the mixture was diluted with propylene glycol monomethyl ether acetate so that the non-volatile content was 60% by mass, and the mass ratio [(A) / (B)] was 5/95, weight. A solution of the comparative resin (R2) having an average molecular weight of 14,600 was obtained.

The compositions of the polycarbonate-modified acrylic resins (1) to (5) and the comparative resins (R1) to (R2) obtained above are shown in Tables 1 and 2.

The abbreviations in the table are as follows.
MMA: Methyl methacrylate HEMA: 2-Hydroxyethyl methacrylate MAA: Methacrylic acid LMA: Lauryl methacrylate SMA: Stearyl methacrylate IBXMA: Isobornyl methacrylate

(Example 6: Preparation and evaluation of paint (1))

[Preparation of paint]
The solution (nonvolatile content 60% by mass) of the polycarbonate-modified acrylic resin (1) obtained in Example 1 above, a leveling agent (“BYK-333” manufactured by Big Chemie Japan Co., Ltd.), dibutyltin dilaurate, and a curing agent ( "Sumijuru N-3300" manufactured by Sumika Cobestro Urethane Co., Ltd.) was uniformly mixed. The blending ratio of the polycarbonate-modified acrylic resin (1) and the curing agent is such that the equivalent of the hydroxyl group in the polycarbonate-modified acrylic resin (1) and the equivalent of the isocyanate group in the curing agent are 1: 1. The blending amount of the dilaurate was 0.1% by mass with respect to the polycarbonate-modified acrylic resin (1). Next, a mixed solvent (methyl isobutyl ketone / diacetone alcohol / ethyl acetate / isobutyl acetate = 30/30 /) so that the viscosity becomes 9 to 10 seconds (23 ° C) with "Viscosity Cup NK-2" manufactured by Anest Iwata Co., Ltd. The paint (1) was prepared by diluting with 30/10 (mass ratio)).

[Preparation of cured coating film X for evaluation]
The paint (1) obtained above is spray-coated on a PC (polycarbonate) base material (50 mm × 70 mm × 1 mm) so that the film thickness after drying is 20 to 30 μm, and 30 at 80 ° C. in a dryer. After heat-drying for 1 minute, it was dried at 25 ° C. for 7 days to prepare a cured coating film for evaluation.

[Preparation of cured coating film Y for evaluation]
The paint (1) obtained above is spray-coated on an ABS (acrylonitrile-butadiene-styrene copolymer) substrate (50 mm × 70 mm × 1 mm) so that the film thickness after drying is 20 to 30 μm, and dried. After heat-drying at 80 ° C. for 30 minutes in a machine, it was dried at 25 ° C. for 7 days to prepare a cured coating film for evaluation.

[Evaluation of adhesion]
A 1 mm wide notch was made on the evaluation cured coating film X obtained above with a cutter to set the number of grids to 100. Next, the cellophane tape was attached so as to cover all the grids, and the operation of quickly peeling it off was performed four times, and the adhesiveness was evaluated from the number of the remaining grids by the following criteria.
○: 100 pieces △: 70 to 99 pieces ×: 69 pieces or less

[Evaluation of water resistance]
After immersing the evaluation cured coating film X obtained above in water at 40 ° C. for 240 hours, the same operation as in the above adhesion evaluation was performed, and the water adhesion resistance was evaluated according to the following criteria.
○: 100 pieces △: 70 to 99 pieces ×: 69 pieces or less

[Evaluation of fragrance resistance]
On the evaluation cured coating film Y obtained above, a fragrance (Little Tree Air Freshener "Royal Pine") cut into 15 mm x 15 mm was placed, and a load was applied with a weight of 500 g at 74 ° C. 4 After drying for an hour, the fragrance was removed, the appearance was visually observed, and the fragrance resistance was evaluated according to the following criteria.
5: No trace on the coating film 4: Slight trace on the coating film 3: Trace on the coating film 2: The base material of the base material is exposed 1: The fragrance cannot be removed from the base material in an adhesive state

(Examples 7 to 10: Preparation and evaluation of paints (2) to (5))
A coating film was prepared by operating in the same manner as in Example 6 except that the polycarbonate-modified acrylic resin (1) of Example 6 was changed to the polycarbonate-modified acrylic resins (2) to (5), and then a cured coating film for evaluation was applied. It was prepared and evaluated.

(Comparative Examples 3 to 4: Preparation and evaluation of paints (R1) to (R2))
A paint film was prepared by operating in the same manner as in Example 6 except that the polycarbonate-modified acrylic resin (1) of Example 6 was changed to the comparative resins (R1) to (R2), and then a coating film for evaluation was prepared. , Each evaluation was performed.

Table 3 shows the evaluation results of the paints (1) to (5) and the paints (R1) to (R2) obtained above.

It was confirmed that the cured coating films obtained from Examples 1 to 5 of the polycarbonate-modified acrylic resin of the present invention were excellent in adhesiveness, water adhesion resistance, and fragrance resistance (Examples 6 to 10).

On the other hand, Comparative Example 1 is an example of an acrylic resin not modified with polycarbonate, but it was confirmed that the adhesiveness and water resistance of the obtained coating film were inferior (Comparative Example 3).

Comparative Example 2 is an example in which the mass ratio of the unsaturated monomer having a carboxyl group in the unsaturated monomer mixture is larger than the upper limit of 10% by mass of the present invention, but the obtained cured coating film has water resistance. It was confirmed that the adhesiveness was inferior (Comparative Example 4).

Claims (5)

In the presence of a polycarbonate diol (A) made from 1,5-pentanediol and 1,6-hexanediol, methyl methacrylate, an unsaturated monomer having a hydroxyl group (b1), and an unsaturated monomer having a carboxyl group. Polycarbonate obtained by reacting (b2) and an unsaturated monomer mixture (B) containing an unsaturated monomer (b3) having an alkyl group having 10 to 24 carbon atoms as an essential component with a radical polymerization initiator. In the modified acrylic resin, the mass ratio of methyl methacrylate in the unsaturated monomer mixture (B) is 30 to 95% by mass, and the mass ratio of the unsaturated monomer (b2) is 10% by mass. A polycarbonate-modified acrylic resin having a mass ratio of less than 1 to 15% by mass of the unsaturated monomer (b3) . The polycarbonate modification according to claim 1, wherein the mass ratio [(A) / (B)] of the polycarbonate diol (A) to the unsaturated monomer mixture (B) is in the range of 2/98 to 80/20. acrylic resin. The polycarbonate-modified acrylic resin according to claim 1 or 2, wherein the unsaturated monomer (b1) has a mass ratio of 1 to 40 % by mass in the unsaturated monomer mixture (B). A coating material containing the polycarbonate-modified acrylic resin according to any one of claims 1 to 3 and a curing agent (C). A plastic molded product characterized by being painted with the paint according to claim 4.