JP5053508B2 - Resin composition for coating - Google Patents

Description

  The present invention relates to a coating resin composition that forms a film having excellent drying and flexibility, a coating composition containing the resin composition, a coating method for coating the coating composition, and the coating composition applied It is related with the color sample card | curd characterized by being.

  Conventionally, in the field of paints, plasticizers such as phthalate plasticizers have been used from the viewpoint of painting workability, finished film finish, etc., but the inclusion of phthalate ester plasticizers in paints When the amount is large, it is known that physical properties of the coating film such as water resistance and weather resistance are lowered. In recent years, since a phthalate ester plasticizer may correspond to an environmental hormone substance, an alternative to a plasticizer is desired.

  As a plasticizer other than the phthalate ester type, Patent Document 1 discloses an acrylic copolymer obtained by a specific production method. The acrylic copolymer has excellent compatibility with thermoplastic resins such as vinyl chloride resin, ABS resin, and AXS resin, and can be suitably used for plasticizing those resins, sealing agents, and molded articles. It has excellent properties and weather resistance, and exhibits the effect of less stickiness on the surface, but when the plasticizer is applied to a paint, the flexibility of the coating film formed from the paint is not sufficient. When a thin base material such as paper or plastic is applied, the coating film may be damaged due to deformation or processing of the base material. Moreover, the improvement of the adhesiveness of the coating film with respect to a base material was calculated | required.

  Patent Document 2 discloses a curable composition containing a vinyl polymer having at least one crosslinking functional group and a polymer plasticizer. According to the composition, it has good heat resistance and weather resistance, and has good coating workability when a paint is applied thereon. There was a problem that the adhesion to the material was not sufficient.

WO01 / 83619 pamphlet JP 2000-178456 A

  An object of the present invention is to provide a coating resin composition suitable for forming a coating film having good coating workability and drying property and excellent adhesion and flexibility even under normal temperature or forced drying conditions.

As a result of intensive studies to solve the above problems, the present inventors have found that the present invention provides a coating resin composition containing a specific acrylic resin having a different molecular weight, cellulose acetate butyrate, and a high boiling point solvent having a specific boiling point. Reached.
That is, the present invention
1.
(A) Acrylic resin having a weight average molecular weight in the range of 10,000 to 100,000, (B) Weight average molecular weight in the range of 1,000 to 5,000, and used for the production of the acrylic resin (B). as monomers to be, n- butyl acrylate and ethyl acrylate containing as a copolymerization component, wherein n- butyl acrylate / use ratio of the ethyl acrylate is n- butyl acrylate / ethyl acrylate weight ratio 10 / 90-90 / Highly an acrylic resin within a range of 10, (C) cellulose acetate butyrate and (D) an ester organic solvent having a boiling point of 250 ° C. to 400 ° C. and / or an ether organic solvent having a boiling point of 250 ° C. to 400 ° C. A coating resin composition comprising a boiling solvent;
2.
The blending ratio of acrylic resin (A), acrylic resin (B) and cellulose acetate butyrate (C) is based on the total weight of resin solids of component (A), component (B) and component (C), The component (A) is in the range of 10 to 85% by weight, the component (B) is in the range of 5 to 80% by weight, and the component (C) is in the range of 10 to 85% by weight. ), The resin composition for coating according to 1, characterized in that it is in the range of 3 to 40% by weight based on the total weight of resin solids of component (B) and component (C),
3.
The coating resin composition according to 1 or 2, further comprising an alkyd resin (E),
4).
A coating composition comprising the coating resin composition according to any one of items 1 to 3,
5.
A coating method characterized by coating the coated surface with the coating composition according to item 4,
6).
Painted articles painted by the coating method according to item 5,
7).
A color sample card, wherein the paint composition according to item 4 is applied;
About.

  According to the coating resin composition of the present invention, a coating film having good coating workability and drying properties and excellent physical properties such as finishing properties and flexibility can be formed even under normal temperature or forced drying conditions. Since the coating composition containing the coating resin composition of the present invention has good coating workability and drying property and can form a coating film having excellent finish and the like, it can be suitably applied to automotive repair coating. In addition, since the formed coating film is excellent in flexibility, bending resistance, and resistance to warp, it can be applied to a deformable substrate, and the coated film after application is cut off. Since it is excellent in cracking properties, it can be suitably used for color sample cards and the like.

  The present invention includes (A) an acrylic resin having a weight average molecular weight in the range of 10,000 to 100,000, (B) an acrylic resin having a weight average molecular weight of 500 or more and less than 10,000, (C) A coating resin composition comprising cellulose acetate butyrate and (D) a high-boiling solvent having a boiling point of 200 ° C. or higher.

Acrylic resin (A)
In the present invention, the acrylic resin (A) is used as a film-forming component, and examples thereof include acrylic resins obtained by polymerization of conventionally known monomers. As the monomer used for the production of the acrylic resin (A), any polymerizable monomer having an ethylenically unsaturated bond can be used, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl. (Meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.), etc. 1-18 linear or Polymerizable unsaturated monomer containing a branched hydrocarbon group; having a cycloalkyl group such as cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, etc. Polymerizable unsaturated monomer; polymerizable unsaturated monomer having an isobornyl group such as isobornyl (meth) acrylate; polymerizable unsaturated monomer having an adamantyl group such as adamantyl (meth) acrylate; styrene, α-methylstyrene, vinyltoluene, etc. (2-acryloyloxyethyl) acid phosphate, (2-methacryloyloxyethyl) acid phosphate, (2-acryloyloxypropyl) acid phosphate, (2-methacrylic acid monomer) Phosphoric acid group-containing polymerizable unsaturated monomers such as (liloyloxypropyl) acid phosphate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl (meta ) _C 2 -C ₈ hydroxyalkyl (meth) acrylates such as acrylate, allyl alcohol, hydroxyl group-containing such as ε- caprolactone modified products of the above _C 2 -C ₈ hydroxyalkyl (meth) acrylate (meth) acrylate; molecular terminal hydroxyl group A hydroxyl group-containing polymerizable unsaturated monomer such as (meth) acrylate having a polyoxyethylene chain which is a carboxyl group-containing polymerizable unsaturated monomer such as (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate; Alkoxysilyl group-containing polymerizability such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane Unsaturated monomers; perfluoroalkyl (meth) acrylates such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; fluorinated alkyl group-containing polymerizable unsaturated monomers such as fluoroolefins; glycidyl (meth) Acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxy Epoxy group-containing polymerizable unsaturated monomers such as cyclohexylpropyl (meth) acrylate and allyl glycidyl ether; Photopolymerizable functional group-containing polymerizable unsaturated monomers such as maleimide group; 1,2,2,6,6-pentamethylpiperidyl (Meth) acrylate, 2,2,2,6,6-tetramethylpiperidinyl (meth) acrylate, etc .; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; ) Acrylonitrile and the like; Amide group-containing polymerizable unsaturated monomers such as (meth) acrylamide and dimethylaminopropyl (meth) acrylamide; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, Nt-butylaminoethyl ( A) Amino group-containing polymerizable unsaturated monomers such as acrylates, adducts of glycidyl (meth) acrylates and amines; 2- (methacryloyloxy) ethyltrimethylammonium chloride, 2- (methacryloyloxy) ethyltrimethylammonium bromide, methacryloyl Aminopropyltrimethylammonium chloride, methacryloylaminopropyltrimethylammonium bromide, tetrabutylammonium (meth) acrylate, tetramethylammonium (meth) acrylate, trimethylbenzylammonium (meth) acrylate, 2- (methacryloyloxy) ethyltrimethylammonium dimethyl phosphate, etc. Quaternary ammonium base-containing polymerizable unsaturated monomer; (Meth) acrylate having a reoxyalkylene chain; 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its sulfonic acid group-containing polymerizable compounds such as sodium salt and ammonium salt Unsaturated monomer; acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) And the like, and these can be used alone or in combination of two or more.

  The copolymerization reaction of the above monomers can be carried out by a known method. For example, azo compounds such as azobisisobutyronitrile and azobis (2,4-valeronitrile); peroxides such as benzoyl peroxide; The reaction is carried out in an organic solvent using a radical polymerization catalyst such as persulfate such as ammonium sulfate. The resulting acrylic resin (A) has a weight average molecular weight in the range of 10,000 to 100,000, preferably in the range of 20,000 to 100,000.

  In this specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured by gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) based on the weight average molecular weight of polystyrene. Columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (both manufactured by Tosoh Corporation, trade names) ), Mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 cc / min, detector: RI.

  If the weight average molecular weight of the acrylic resin (A) is less than 10,000, defects such as a decrease in film properties such as bending resistance and elongation, and a decrease in drying property occur. Since the resin composition has a high viscosity, problems such as coating workability and a decrease in the finish of the formed coating film may occur, which is not preferable.

Acrylic resin (B)
In the present invention, the acrylic resin (B) is used as a plasticizer, and the weight average molecular weight is preferably in the range of 500 or more and less than 10,000 from the viewpoint of the finish of the formed coating film. Is preferably in the range of 1,000 to 5,000.

  In the present invention, the acrylic resin (B) can be composed of the same monomers as those listed in the description of the acrylic resin (A) as a copolymerization component, and particularly n-butyl acrylate and ethyl as monomers. It is desirable to contain acrylate as a copolymerization component from the viewpoint of the finish of the formed coating film.

  Here, the use ratio of n-butyl acrylate / ethyl acrylate is in the range of 10/90 to 90/10, preferably 20/80 to 80/20 in terms of weight ratio from the viewpoint of handling of the acrylic resin (B). It is desirable.

  Moreover, as for the said acrylic resin (B), it is desirable to comprise a double bond containing acrylic resin as a part of the component. By comprising a double bond-containing acrylic resin, the acrylic resin (B) can act as a reactive diluent as well as a role as a plasticizer.

  As a method for producing the acrylic resin (B), for example, the above monomers are copolymerized in the presence of a chain transfer agent, a polymerization initiator and a solvent as necessary, for example, at a high temperature of 180 ° C. to 350 ° C. The method of doing can be mentioned.

Cellulose acetate butyrate (C)
In the present invention, cellulose acetate butyrate (C) (hereinafter sometimes referred to as CAB) is a cellulose derivative obtained by further butyrylating a partially acetylated product of cellulose, and formed from the coating resin composition of the present invention. It is used in order to improve the drying property of the coating film. The acetyl group content is preferably 1 to 30% by weight, preferably 1 to 14% by weight, and the butyryl group content is preferably 16 to 60% by weight, preferably 35 to 60% by weight. ASTM-D1343- The viscosity when measured by the viscosity measuring method described in 54T (Formul A) is 0.005 to 5 seconds, preferably 0.005 to 1 second. The number average molecular weight is preferably in the range of 10,000 to 120,000, particularly 20,000 to 35,000.

  In this specification, the number average molecular weight is a value obtained by converting the number average molecular weight measured by gel permeation chromatography based on the number average molecular weight of polystyrene. The measurement conditions for gel permeation chromatography can be the same as the measurement conditions for the weight average molecular weight.

  Specific examples of the cellulose acetate butyrate (C) include a product of Eastman Chemical, Inc. of the United States, for example, a trade name [butyryl group content (% by weight) up to the second digit of the former number, and also three digits. The eye indicates the hydroxyl group content (% by weight), and the latter number indicates the viscosity (seconds)], CAB-171-2, CAB-381-0.5, CAB-381-2, CAB-531-1 , CAB-551-0.2, CAB-551-0.1, CAB-551-0.01 and the like are advantageously used.

High boiling point solvent (D)
In the present invention, a high boiling point solvent (D) is included in order to achieve both the drying property and flexibility of the coating film formed from the coating resin composition of the present invention, as well as the finish property. Specific examples of the high boiling point solvent (D) include volatile compounds having a boiling point of 200 ° C. or higher, preferably 250 to 400 ° C. When the boiling point is less than 200 ° C., the flexibility of the coating film formed using the coating composition of the present invention is not preferable.

  The boiling point in the present specification means that a 100 ml sample is charged into a 200 ml flask equipped with a condenser and a thermometer in an atmosphere of 25 ° C. and 1 atm so that the distillation amount is 4 to 5 ml / min. The maximum temperature among the boiling points measured by distillation while adjusting the heating.

  Examples of the high boiling point solvent (D) include propylene glycol monomethyl ether acetate, isoamyl acetate, oxohexyl acetate, methyl methoxybutyl acetate, ethyl ethoxypropionate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono Butyl ether acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 2,2,4-trimethyl-1, Ester-based organic solvents such as 3-pentanediol mono 2-ethylhexanoate and 2,2,4-trimethyl-1,3-pentanediol di-2-ethylhexanoate; benzyl alcohol Alcohol, organic solvent such as dexanol, diethylene glycol, isotridecanol, 1,3-octylene glycol, glycerin; ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, Examples thereof include ether-based organic solvents such as diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, diethylene glycol mono 2-ethylhexyl ether, propylene glycol monophenyl ether, and tripropylene glycol methyl ether, which can be used alone or in combination. As the high boiling point organic solvent (D), an ester organic solvent and / or an ether organic solvent are suitable from the viewpoint of the drying property of the formed coating film. From the point of non-adhesiveness of the formed coating film, ester organic solvents, particularly 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3- From pentanediol diisobutyrate, 2,2,4-trimethyl-1,3-pentanediol mono 2-ethylhexanoate, 2,2,4-trimethyl-1,3-pentanediol di-2-ethylhexanoate At least one compound selected from the group consisting of

Coating Resin Composition The coating resin composition of the present invention comprises (A) an acrylic resin having a weight average molecular weight in the range of 10,000 to 100,000, and (B) a weight average molecular weight of 500 or more and less than 10,000. (C) Cellulose acetate butyrate and (D) High boiling point solvent having a boiling point of 200 ° C. or higher as essential components. Component (A), Component (B) and Component (C ) Is blended based on the total weight of resin solids of component (A), component (B) and component (C),
Component (A) is 10 to 85% by weight, preferably 15 to 70% by weight,
Component (B) is 5 to 80% by weight, preferably 5 to 60% by weight,
Component (C) is 10 to 85% by weight, preferably 25 to 80% by weight
It is desirable to be within the range.

  When the blending ratio of the component (A) is less than 10% by weight, the drying property, bending resistance, etc. of the coating film formed using the coating resin composition of the present invention may decrease, while 85% by weight. If it exceeds 1, the viscosity of the coating resin composition of the present invention will increase, and the coating workability may be lowered, or the flexibility of the formed coating film may be lowered. When the blending ratio of the component (B) is less than 5% by weight, the flexibility of the coating film formed by using the coating resin composition of the present invention and the adhesion to the material may be reduced, while 80% by weight. When it exceeds%, the drying property of the coating film formed using the coating resin composition of the present invention may be lowered. When the blending ratio of the component (C) is less than 10% by weight, the drying property of the coating film formed using the coating resin composition of the present invention may be deteriorated. The flexibility and finish (gloss) of the coating film formed using the coating resin composition may be lowered.

  In addition, the blending ratio of the high boiling point solvent (D) is the component (A) from the viewpoint of the flexibility of the coating film formed using the coating resin composition of the present invention, the adhesion to the substrate and the drying property. , Based on the total weight of the resin solids of component (B) and component (C), it is desired to be in the range of 3 to 40% by weight, preferably 5 to 30% by weight.

Alkyd resin (E)
The coating resin composition of the present invention can contain an alkyd resin (E) in order to further improve the adhesion to the substrate. The alkyd resin (E) includes ordinary alkyd resins, oil-free alkyd resins, epoxy-modified alkyd resins, amino-modified alkyd resins and the like. As raw materials used for the production of the alkyd resin (E), dry oil such as flax oil, soybean oil, castor oil, dehydrated castor oil, coconut oil, and fatty acids of the dry oil; phthalic acid, phthalic anhydride Monovalent and polyvalent carboxylic acids, such as isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid, succinic acid, adipic acid, sebacic acid, benzoic acid Multivalent such as ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, 1,3-butylene glycol, hydrogenated bisphenol, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, cyclohexanedimethanol, etc. Alcohol, and these alkylene oxides And epoxy resins. Selected from those suitably be used in any proportion.

  The number average molecular weight of the alkyd resin (E) is preferably in the range of 1,000 to 100,000, particularly 1,500 to 50,000.

  As content of the said alkyd resin (E), it is 50 weight% or less in the resin solid content contained in the resin composition for coating | cover of this invention, Preferably it can exist in the range of 2-30 weight%.

Coating composition The present invention is a coating composition comprising the coating resin composition.

  The coating composition of the present invention may be a clear coating or an enamel coating, and can be used as a base coating and a top coating. It can also be used as an intermediate coating.

  As the pigment used in the case of enamel paint, conventionally known pigments can be used, and pigments such as luster pigments, colored pigments, extender pigments, and rust preventive pigments that are usually used in the paint field can be used without particular limitation. . Examples of bright pigments include metallic pigments such as aluminum powder, bronze powder, copper powder, tin powder, lead powder, and iron phosphide; pearl pigments such as pearl-like metal-coated mica powder and mica-like iron oxide, Color pigments include white pigments such as titanium oxide; black pigments such as carbon black, acetylene black, lamp black, bone black, graphite, iron black, aniline black; yellow iron oxide, titanium yellow, monoazo yellow, condensed azo yellow, Yellow pigments such as azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, permanent yellow; orange pigments such as permanent orange; red iron oxide, naphthol AS azo red, ansanthrone, anthra Quinonyl Red pigments such as cobalt, quinacridone violet, dioxazine violet; cobalt blue, phthalocyanine blue, sren blue, etc. Blue pigments; green pigments such as phthalocyanine green; and the like, as extender pigments, zinc powder, barita powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, silica, white carbon, diatomaceous earth, Examples include talc, magnesium carbonate, alumina white, gloss white, and mica powder. Examples of the rust preventive pigment include aluminum tripolyphosphate, aluminum phosphomolybdate, and zinc phosphate.

  In the coating composition of the present invention, the amount of the pigment is, when applied as a top coating, from the viewpoint of finish properties and concealing properties, coating properties such as water resistance, etc. 1 to 100% by weight, preferably 1 to 80% by weight, and more preferably 1 to 60% by weight. On the other hand, when the coating composition of the present invention is applied as an undercoat, the pigment is preferably 50 to 600% by weight, preferably based on the resin solid content in the coating, in order to achieve both coating properties such as abrasiveness and water resistance. Can be contained in the range of 100 to 500% by weight, more preferably 100 to 350% by weight.

  Moreover, the coating composition of this invention can contain a surface-control agent from the point which makes finishing property favorable. As such a surface conditioner, conventionally known ones can be used without limitation, and examples thereof include acrylic, silicone and fluorine copolymers. The surface conditioner may be contained in the range of 0.001 to 10% by weight, preferably 0.01 to 5% by weight, based on the resin solid content in the paint.

  The coating composition of the present invention further contains coating additives such as a dispersant, a drying agent, a thickener, an antifoaming agent, an antiseptic, and an organic solvent other than the high boiling point solvent (D) as necessary. Can do.

  It is desirable from the viewpoint of storage stability that the coating composition of the present invention has a viscosity of 60 to 140 KU, particularly 70 to 105 KU, adjusted to a temperature of 25 ° C. and measured with a Stormer viscometer.

  The method of the present invention is a coating method characterized in that the coating composition is applied to a surface to be coated.

  The coated surface is not particularly limited. For example, iron, aluminum, brass, copper plate, stainless steel plate, tin plate, galvanized steel plate, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) ) Metals such as plated steel sheets; Surface-treated metals that have been subjected to chemical conversion treatment such as zinc phosphate treatment or chromate treatment on the surface of these metals; Surfaces of materials to be coated such as plastic, wood, concrete, mortar, etc. For example, the surface of the material is a primer surface such as a primer and / or an intermediate coating and / or a top coating. Can do.

  Also, since the formed coating film has good flexibility and crack resistance, the coating composition of the present invention is applied to a base material for a color sample card used in fields such as general industrial use, architectural use, and automobile repair. You can also

  The color sample card is generally used for presenting a desired color or placing it in the vicinity of the coating film during the painting operation to determine the color matching of the painted portion. As the color sample card base material, conventionally known ones can be used without limitation, and examples thereof include plastic, metal, paper, and the like, and it is desirable that the size is convenient for carrying. In addition, after the coating composition is applied to the color sample card substrate, a clear coating can be applied. The color sample card may be a color sample book in which a plurality of different color sample cards are collected by a combining unit.

  In the method of the present invention, the coating method of the coating composition is not particularly limited and can be appropriately selected from conventionally known methods. For example, when used for top coating of automobile repair coating, it is applied by spraying and dried at 20 to 80 ° C. for 5 to 60 minutes, and the resulting coating film has a dry film thickness of 1 to 300 μm, preferably 5 to 100 μm. Can be within.

  Hereinafter, the present invention will be described more specifically with reference to examples. “Parts” and “%” are “parts by weight” and “% by weight”.

Examples 1-6 and Comparative Examples 1-6
Each component was blended and mixed in the mixing composition shown in Table 1 below in a stirring and mixing container to obtain each coating composition. In addition, Table 1 shows the paint viscosities measured by a Stormer viscometer after adjusting each paint composition so that the temperature is 25 ° C.

(Note 1) 55% acrylic resin solution:
A reactor having a capacity of 4 liters equipped with a thermometer, a stirrer, a reflux condenser and a dropping pump was charged with 68 parts of butyl acetate (boiling point: 126.5 ° C.), heated to 110 ° C. with stirring, and the following monomer mixture: And a polymerization initiator mixture were added dropwise at a constant rate at 110 ° C. over about 3 hours.
i-butyl methacrylate 69.75 parts methyl methacrylate 10 parts 2-hydroxyethyl acrylate 20 parts methacrylic acid 0.25 parts azobis (2,4-dimethylvaleronitrile) 0.2 parts Continued. Thereafter, 0.5 part of azo (2,4-dimethylvaleronitrile) dissolved in 14 parts of butyl acetate as an additional catalyst was dropped at a constant rate over 1 hour. And after completion | finish of dripping, it maintained at 110 degreeC for 1 hour, and complete | finished reaction. The obtained acrylic resin solution was a uniform and transparent solution with a non-volatile content of 55.0%, and the weight average molecular weight of the resin was 50,000.
(Note 2) 60% alkyd resin solution: In a 4 liter flask equipped with a reflux condenser and a stirrer, 47.9 parts of coconut oil fatty acid, 64.5 parts of pentaerythritol, 138.4 parts of phthalic anhydride, benzoic acid 7.9 parts, 18.5 parts of ethylene glycol, 129.4 parts of toluene (boiling point 110.6 ° C.), 55.4 parts of xylene (boiling point 140 ° C.) are charged to 240 ° C. for 4 hours with stirring in a nitrogen atmosphere. The mixture was heated and reacted for 7 hours to obtain an alkyd resin solution having a number average molecular weight of 3000 and a solid content of 60%.
(Note 3) 25% CAB solution: (“CAB381-0.5” (trade name, manufactured by Eastman Chemical Co., Ltd., cellulose acetate butyrate having a number average molecular weight of 30,000) is butyl acetate / methyl isobutyl ketone (boiling point 116 ° C.) = 50/25 dissolved, solid content 25%)
(Note 4) Acrylic resin: A monomer mixture of 70 parts of n-butyl acrylate, 30 parts of ethyl acrylate, 20 parts of isopropyl alcohol (boiling point 82.3 ° C.) and 0.5 part of ditert-butyl peroxide is added to a 1 L container. Created. Next, a pressurized reaction vessel equipped with a 300 ml stirrer is filled with ethyl propionate (boiling point 99 ° C.), the temperature in the vessel is maintained at 230 ° C., and the pressure in the reaction vessel is adjusted to 2.45-2 by a pressure regulator. Adjusted to 65 MPa. While maintaining the pressure of the reactor, the monomer mixture is fed to the reactor so that the feed rate is 23 g / min, and a reaction product having a volume equal to the feed volume of the monomer mixture is continuously withdrawn from the outlet of the reactor. A low molecular weight acrylic resin was obtained. The resin had a weight average molecular weight of 1400 and contained an acrylic resin having a double bond at the end as a part of its components.
(Note 5) High boiling point solvent A: “CS-12” (trade name, manufactured by Chisso Corporation, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate boiling point 253 ° C.)
(Note 6) High boiling point solvent B: Diethylene glycol monobutyl ether (boiling point 255 ° C.)
(Note 7) Surface conditioner: “BYK-300” (trade name, polydimethylsiloxane copolymer produced by BYK).

Preparation of test coating plate Each coating composition obtained above was diluted with toluene / xylene / butyl acetate / methyl isobutyl ketone = 50/20/10/20 thinner. A sample that was adjusted to 13 seconds at 4/25 ° C. was used. “Silicon off” (trade name, manufactured by Kansai Paint Co., Ltd., degreasing agent) is coated with a plate coated with an automotive baking paint (Magiclon TC-71, manufactured by Kansai Paint Co., Ltd.) and polished with # 1000 sandpaper. Each sample was air spray-coated so that the dry film thickness was 80 μm and dried at 25 ° C. for 7 days as a test coated plate, and subjected to the following evaluation test. The results are also shown in Table 1.
(* 1) Finishing property About the finishing property of each test coating board, the degree of bubble breakage and the gloss were visually evaluated.
○: No broken bubble mark, △: Some broken bubble marks, x: Many broken bubble marks and gloss; ○: Very good gloss, Δ: Slightly good gloss, ×: No gloss ( * 2) In a temperature-controlled room with a non-adhesive temperature of 40 ° C., two sheets of 50 mm square gauze were stacked on the test coating plate, and a 500 g weight was placed thereon. After 24 hours, the gauze marks on the surface of the test coating plate were visually evaluated.
A: No change in coating film appearance, B: Almost no change in coating film appearance, B: Gauze trace clearly remains, X: Gauze sticks to the coating surface (* 3) Bending resistance After bending at an angle of °, the appearance was visually evaluated.
○: Good, △: Slightly peeled, ×: Peeled (* 4) Adhesion Cut each test coating plate with a cutter with 2 mm x 100 grids until reaching the surface to be coated, and apply adhesive tape on top The remaining number of grids remaining on the coating film was displayed.

Claims (7)

(A) Acrylic resin having a weight average molecular weight in the range of 10,000 to 100,000, (B) Weight average molecular weight in the range of 1,000 to 5,000, and used for the production of the acrylic resin (B). as monomers to be, n- butyl acrylate and ethyl acrylate containing as a copolymerization component, wherein n- butyl acrylate / use ratio of the ethyl acrylate is n- butyl acrylate / ethyl acrylate weight ratio 10 / 90-90 / Highly an acrylic resin within a range of 10, (C) cellulose acetate butyrate and (D) an ester organic solvent having a boiling point of 250 ° C. to 400 ° C. and / or an ether organic solvent having a boiling point of 250 ° C. to 400 ° C. A coating resin composition comprising a boiling point solvent. The blending ratio of acrylic resin (A), acrylic resin (B) and cellulose acetate butyrate (C) is based on the total weight of resin solids of component (A), component (B) and component (C), The component (A) is in the range of 10 to 85% by weight, the component (B) is in the range of 5 to 80% by weight, and the component (C) is in the range of 10 to 85% by weight. 2) The resin composition for coating according to claim 1, wherein the content is in the range of 3 to 40% by weight based on the total weight of resin solids of component (B) and component (C). The coating resin composition according to claim 1 or 2, further comprising an alkyd resin (E). A coating composition comprising the coating resin composition according to any one of claims 1 to 3. A coating method comprising applying the coating composition according to claim 4 to a surface to be coated. A coated article coated by the coating method according to claim 5. A color sample card, wherein the coating composition according to claim 4 is coated.