JPH061949A - Coating composition - Google Patents

Abstract

PURPOSE:To provide the subject composition causing no spray and reversion unevennesses, excellent in coating workability and durability, useful for e.g. metallic base coating, comprising each specific graft copolymer and modified vinyl copolymer and a polyisocyanate compound. CONSTITUTION:The objective composition comprising (A) a graft copolymer 60-120 in hydroxyl value prepared by copolymerization between (1) 10-30wt.% of a macromonomer, (2) 0-30wt.% of styrene and (3) 40-90wt.% of another ethylenically unsaturated monomer, (B) a modified vinyl copolymer prepared by copolymerization between (a) 5-75wt.% of cellulose acetate butyrate and (b) 95-25wt.% of a vinyl monomer mixture of 1-50wt.% of at least one kind of OH-contg. functional vinyl monomer and 99-50wt.% of another vinyl monomer, and (C) a polyisocyanate compound, pref. in a weight ratio A/B of (10:90) to (90:10). The amount of the component C to be incorporated is pref. such that the equivalent ratio NCO/OH be 0.52 to 2.0 (where, OH is the sum of the respective hydroxyl groups in the components A and B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for coating, and more particularly, it is particularly effective for a metallic base coat containing a specific graft copolymer, a modified vinyl copolymer and a polyisocyanate compound. It relates to a coating composition.

[0002]

2. Description of the Related Art Conventionally, acrylic lacquers, acrylic urethane paints, and amino-acrylic resin paints have been used for repairing automobiles, painting industrial machinery, buildings, structures, furniture (including steel) and repairing them. However, acrylic urethane paints have become the mainstream in the field of automotive repair paints because of their dryness at room temperature, coating surface, weather resistance, etc.
In this field, a so-called metallic finish color in which a transparent clear is applied to a paint containing an aluminum paste (hereinafter referred to as a metallic base) has become mainstream in this field.

[0003]

The problems with the metallic finish color are that the distribution and orientation of aluminum becomes uneven during coating of the metallic base, resulting in unevenness (blow unevenness and below), and the metallic base at room temperature. After being left to dry to the touch, a clear coating is applied on top of it, but the clear coating causes uneven distribution and orientation of aluminum in the lower metallic base, resulting in unevenness (modorimura and the following description).

As a means for solving this problem, a part of a fibrin derivative such as nitrocellulose or cellulose acetate butyrate is contained in the metallic base resin composition to accelerate the drying property and control the orientation of aluminum, and the hydroxyl group. To make the viscosity of the coating film after coating relatively high by making the molecular weight of the contained graft polymer relatively high,
Further, although the SP value is made different from that of the resin used for clearing, the present situation is that it has not yet resolved flicker unevenness and moduli unevenness.

[0005]

Therefore, the present inventors have arrived at the present invention as a result of extensive studies to obtain a coating composition for metallic base which does not cause flicker and moduli unevenness.

That is, the present invention relates to "(1) [I] (a) macromonomers 10 to 3".
0% by weight (b) Styrene 0 to 30% by weight, and (c) 40 to 90% by weight of other ethylenically unsaturated monomer, and a hydroxyl group-containing graft copolymer having a hydroxyl value of 60 to 120. II] (a) Cellulose acetate butyrate 5-7
A vinyl monomer mixture 9 comprising 5% by weight and (b) at least 1 to 50% by weight of a functional vinyl monomer containing a hydroxyl group and 99 to 50% by weight of another copolymerizable vinyl monomer.
Coating composition characterized by containing a modified vinyl-based copolymer obtained by copolymerizing 5 to 25% by weight and [III] polyisocyanate compound (2) Mixing of [I] and [II] The ratio is [I] / [II]
= 10/90 to 90/10, the coating composition according to item 1, wherein the graft polymer [I] has a weight average molecular weight of 10,
000 to 60,000 and a glass transition temperature of 0 to 8
The coating composition according to item 1, wherein the temperature is in the range of 0 ° C. (4) (a) The macromonomer is an oligomer or polymer having a polymerizable unsaturated group at the terminal, 1 to 3.
The coating composition according to any one of items. (5) (a) Macromonomer has a carboxyl group having a mercaptan-based chain transfer agent. In the presence of a mercaptan-based chain transfer agent, the terminal carboxyl group of an oligomer or polymer having a terminal carboxyl group produced by polymerizing a radical polymerizable monomer is polymerizable with an epoxy group. The coating composition according to any one of items 1 to 3, which is a product obtained by reacting a compound having an unsaturated group. (6) The amount of polyisocyanate compounded is NCO / OH = 0.52 to the sum of hydroxyl groups in the copolymer in an equivalent ratio.
The coating composition according to any one of items 1 to 5, which is 2.0. Regarding

[0007]

As described above, the present invention comprises [I] a hydroxyl group-containing graft copolymer, [II] a modified vinyl copolymer, and [II]
I] A coating composition comprising a polyisocyanate compound. Hereinafter, each component and action will be described in detail.

[I] Hydroxyl group-containing graft copolymer The macromonomer (a) for obtaining the [I] hydroxyl group-containing graft copolymer in the present invention has a weight average molecular weight of 1,
000 to 25,000 or 1,500 to 15,000
It is preferably in the range of 0. When the weight average molecular weight is less than 1,000, the resulting coating film tends to have reduced unevenness of fluffiness and moduli, while when it is greater than 25,000, it is copolymerized with (b) styrene and (c) other ethylenic unsaturation. Copolymerization reactivity with monomers tends to be poor.

In the present invention, the macromonomer means an oligomer or polymer having a polymerizable unsaturated group at the terminal, and is an abbreviation of Macromolecular Monomer. In the macromonomer in the present invention, as a method of introducing a polymerizable unsaturated group at the terminal, for example, a method of acting allyl chloride, methacrylic acid chloride or the like on the living polymer anion, epichlorohydrin on the living polymer anion to the polymer terminal A method of introducing a glycidyl group and reacting this with an unsaturated carboxylic acid such as (meth) acrylic acid. A mercaptan-based chain transfer agent having a carboxyl group, for example, mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid is polymerized with a radically polymerizable monomer in the presence of an oligomer or polymer having a terminal carboxyl group, Glycidyl methacrylate, glycidyl acrylate for the terminal carboxyl group,
Method of reacting a compound having an epoxy group and a polymerizable unsaturated group such as allyl glycidyl ether, a mercaptan chain transfer agent having a hydroxyl group, for example, by polymerizing a radical polymerizable monomer in the presence of 2-mercaptoethanol A method for obtaining an oligomer or polymer having a hydroxyl group, isocyanating this terminal hydroxyl group with a diisocyanate compound, and reacting this isocyanate group with a compound having a hydroxyl group such as hydroxyethyl (meth) acrylate and a polymerizable unsaturated group, or a terminal hydroxyl group A method of reacting a monoisocyanate having a polymerizable unsaturated group such as isocyanatoethylmethacrylate with an oligomer or polymer having a group, and the presence of a mercaptan chain transfer agent having an amino group such as 2-aminoethanethiol under Polymerizing the radical polymerizable monomer to obtain an oligomer or polymer having terminal amino groups, the ones in a method of reacting a compound having a polymerizable unsaturated group as well as epoxy groups described above can be utilized.

Among the above-mentioned methods for producing a macromonomer, the radical polymerization method which is advantageous in industrial production and the method which is easy to carry out the reaction are particularly preferable. In the above method, a tertiary amine or a quaternary ammonium salt can be used as a reaction catalyst used when reacting an oligomer or polymer having a terminal carboxyl group with glycidyl methacrylate or the like. In order to prevent coloring of the macromonomer, it is preferable to use a quaternary ammonium salt such as tetrabutylammonium bromide.

The constitutional unit of the (a) macromonomer in the present invention is a known ethylenically unsaturated monomer, and representative examples thereof include (A) methyl acrylate, ethyl acrylate, propyl acrylate, Isopropyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, (Meth) such as 2-ethylhexyl, octyl methacrylate, lauryl methacrylate
C ₁ -C ₁₆ alkyl ester of acrylic acid (B) Glycidyl acrylate, glycidyl methacrylate: methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, ethoxybutyl acrylate, ethoxybutyl methacrylate, etc. (meth) _C 2 _{~ 16} acrylic acid
Alkoxyalkyl ester (C) allyl acrylate, (meth) alkenyl esters of C ₂ ~ ₃ of acrylic acid (D) hydroxyethyl acrylate and allyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate,
Such as hydroxypropyl methacrylate (meth) and C ₂ ~ ₈ hydroxyalkyl esters (E) commercially available acrylic acid is Placcel FA-1 (2-hydroxyethyl 1 mol acrylic acid, a product of Daicel Chemical Industries, Ltd. ε- Monomers to which 1 mol of caprolactone was added, Praxel FM-1, Praxel FM-3, Praxel FM-5, (monomers obtained by adding 1 mol, 3 mol and 5 mol of ε-caprolactone to 1 mol of 2-hydroxyethyl methacrylate, respectively. ), A hydroxyl group-containing (meth) acrylate ester such as TONE M-100 (a monomer obtained by adding 2 mol of ε-caprolactone to 1 mol of 2-hydroxyethyl acrylate), which is a product of Union Carbide (US), and a lactone. Adduct with 1 to 5 moles (F) dimethylaminoethyl Acrylic unsaturated monomers such as acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other aminoalkyl esters of (meth) acrylic acid, acrylamide, methacrylamide: acrylic acid, and methacrylic acid: (G) Styrene , Α-methylstyrene, vinyltoluene, acrylonitrile, methacrylonitrile, acrolein, methacrolein, butadiene, isoprene and the like unsaturated monomers other than acrylic unsaturated monomers can be mentioned, these are desired physical properties. It is used as appropriate.

The macromonomer according to the present invention is obtained by the above-mentioned methods (1) to (3) using the above-mentioned ethylenically unsaturated monomer. In the method of radical polymerization of to, the above ethylenically unsaturated monomer can be polymerized by using a polymerization initiator, especially an azo initiator together with a mercaptan-based chain transfer agent.

In the present invention, the above-mentioned (a) macromonomer is copolymerized with (b) styrene and (c) other ethylenically unsaturated monomer to form a hydroxyl group-containing graft copolymer, but (c) other As the ethylenically unsaturated monomer, the ethylenically unsaturated monomer excluding styrene from the above-mentioned constituent units of the macromonomer (a) can be used.

The copolymerization of the above components (a) to (c) can be carried out by radical polymerization in the presence of a polymerization initiator such as a peroxide initiator or an azo type initiator by a solution polymerization method, A graft copolymer in which the components (b) and (c) form a trunk polymer and the component (a) forms a side chain is obtained. The graft copolymer obtained by copolymerizing the above components (a) to (c) is a main component forming a coating film and needs to have a hydroxyl value in the range of 60 to 120.
The component and / or component (c) having a hydroxyl group is used to obtain a graft copolymer within the above range. When the hydroxyl value is less than 60, the cross-linking density of the coating film is low and the physical properties of the coating film are poor. On the other hand, when the hydroxyl value is larger than 120, the viscosity of the graft copolymer becomes high and the non-volatile content at the time of coating becomes low, which adversely affects the coating workability.

The hydroxyl group-containing graft copolymer preferably has a weight average molecular weight of 10,000 to 60,000. When the weight average molecular weight is less than 10,000, it is difficult to obtain a satisfactory effect of preventing moduli unevenness, while when the weight average molecular weight exceeds 60,000, atomization during spray coating is poor, and the leveling property after coating is poor. Therefore, the occurrence of flicker unevenness tends to increase. Further, the hydroxyl group-containing graft copolymer has a glass transition temperature (Tg) of 0 to
It is desirable to be in the range of 80 ° C. If the Tg is less than 0 ° C, the initial drying property tends to be deteriorated and moduli unevenness tends to occur. On the other hand, if the Tg exceeds 80 ° C, the drying tends to be too fast to cause flicker unevenness.

The blending amount of each component with respect to the total amount of the components (a) to (c) in the production of the hydroxyl group-containing graft copolymer is within the following range. (A) component 10 to 30% by weight, preferably 10 to 20
% By weight (b) component 0 to 30% by weight, preferably 0 to 20% by weight (c) component 40 to 90% by weight, preferably 60 to 90%
% In the above blending amount, if the amount of the component (a) is less than 3% by weight, the effect of preventing flicker unevenness is not sufficient, and for the prevention of flutter unevenness, it is sufficient that the amount of the component (a) is 3 to 30% by weight Even if the component (a) is blended in an amount of more than 30% by weight, further prevention of flicker unevenness is hardly recognized, and the durability of the coating film is rather deteriorated. Also, the amount of component (b) is 10
If it is less than 10% by weight, the unevenness of the fluffiness is deteriorated, while the amount of the component (b) is 5
If it exceeds 0% by weight, the compatibility tends to deteriorate. Commercially available products of the (a) macromonomer in the present invention include products AA-2 and A of Toa Gosei Kagaku Co., Ltd. shown in Table 1 below.
A-6, AB-2, AB-6 etc. can be mentioned.

[0017]

[Table 1]

Next, the [II] modified vinyl copolymer of the present invention will be described below.

[II] Modified Vinyl Copolymer The modified vinyl copolymer used in the present invention is a graft copolymer of a mixture of cellulose acetate butyrate and a vinyl monomer, and controls the distribution and orientation of aluminum to prevent flicker and Although it has the effect of preventing moduli unevenness, this graft copolymer is also a component that forms a coating film.

Each component of the modified vinyl copolymer will be described, and then the copolymer will be described. (A) Cellulose Acetate Butyrate Cellulose acetate butyrate used in the production of the modified vinyl copolymer in the present invention (hereinafter, referred to as “CA
"B" is abbreviated as "B") is a cellulose derivative obtained by further butyl esterifying a partially acetylated product of cellulose, and CAB which can be preferably used in the present invention has an acetyl group content of generally 1 to 30% by weight, preferably 1 to
14% by weight, the butyl group content is generally 16-60% by weight, preferably 35-60% by weight, and the AST
The viscosity as measured by the viscosity measurement method described in M-D1343-54T (Formula A) is generally 0.
It is within the range of 005 to 5 seconds, preferably 0.005 to 1 second. Specifically, a product manufactured by Eastman Kodak Company in the United States, such as a trade name [the butyl group content (% by weight) up to the second digit of the former number, and also 3
The digit indicates the hydroxyl group content, and the latter number indicates the viscosity (seconds)], EAB-171-2, EAB-38
1-0.5, EAB-381-2, EAB-531
1, EAB-551-0.2, EAB-551-0.0
Grades such as 1 are advantageously used, among them compatibility,
From the viewpoint of solubility, viscosity, etc., EAB-381-0.
5, EAB-551-0.2 and EAB-551-
0.01 is particularly preferred.

(B) Vinyl Monomer Mixture The vinyl monomer mixture copolymerized with CAB according to the present invention comprises at least two different vinyl monomers, at least one of which is a functional vinyl monomer containing a hydroxyl group, Thereby, a functional group (hydroxyl group) can be introduced into the obtained modified vinyl copolymer. As the hydroxyl group-containing vinyl monomer,
For example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, C ₂ -C ₁₂ hydroxyalkyl esters of such acrylic acid or methacrylic acid such as hydroxypropyl methacrylate; N- methylol acrylamide, N- methylolacrylamide call methacrylamide , N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, N, N-dihydroxyethyl acrylamide, N, N-dihydroxyethyl methacrylamide, etc. mono- or di-C ₁ -C ₁₂ hydroxy of acrylic acid or methacrylic acid. Examples thereof include alkylamides. The above hydroxyl group-containing vinyl monomers can be used alone or in combination of two or more kinds.

On the other hand, examples of other copolymerizable vinyl monomers used in combination with the hydroxyl group-containing vinyl monomer include radically polymerizable α, β-ethylenically unsaturated bonds of 1 to 2.
A compound containing only one, preferably one, is suitably used, and for example, one or more of the following (H) to (K) can be appropriately selected and used. (H) Vinyl aromatic compounds such as styrene, vinyltoluene, α-methylstyrene, or other vinyl monomers such as vinyl acetate, acrylonitrile, methacrylonitrile; (I) methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, ethyl Methacrylate, n-butyl acrylate, n-butyl methacrylate, 1-butyl acrylate, 1-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate,
2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, etc., alkyl or cycloalkyl esters having 1 to 24 carbon atoms of acrylic acid or methacrylic acid; (J) acrylamide, Methacrylamide, N-methylacrylamide, N-ethylmethacrylamide, N,
Acrylic or methacrylamide such as N-dimethyl acrylamide, N, N-diethyl methacrylamide. (K) Glycidyl group-containing vinyl monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, methacryl glycidyl ether, glycidyl methyl acrylate, and glycidyl methyl methacrylate.

These other copolymerizable vinyl monomers can be used alone or in combination of two or more. Of these vinyl monomers, 2-hydroxyethyl methacrylate is used as the hydroxyl group-containing vinyl monomer, and C ₁ -C ₆ alkyl ester of styrene and acrylic acid or methacrylic acid is used as another vinyl monomer that is copolymerizable, such as methyl acrylate and methyl methacrylate. , Ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate and the like are preferable.

According to the invention, when these other copolymerizable vinyl monomers are used in combination with the hydroxyl-containing vinyl monomer, the hydroxyl-containing vinyl monomer is from 1 to 50, based on the weight of the vinyl monomer mixture. %, Preferably 5 to 35% by weight, and thus the remaining 99 to 50% by weight, preferably 95 to 65% by weight.
% By weight may be the other copolymerizable vinyl monomer. If the proportion of the hydroxyl group-containing vinyl monomer in the vinyl monomer mixture is less than 1% by weight, the cross-linking reaction of the coating film formed becomes insufficient, so that the gasoline resistance, solvent resistance, chemical resistance, water resistance, etc. Decline, while
If it exceeds 50% by weight, the coating film becomes brittle, and further, chemical resistance, water resistance, weather resistance and the like are deteriorated.

Further, in the present invention, a carboxyl group-containing vinyl monomer may be used in combination with the vinyl monomer mixture for the purpose of improving adhesion, flexibility, pigment dispersibility, compatibility and the like. Examples of the carboxyl group-containing vinyl monomer include C3 to C6 unsaturated aliphatic groups such as acrylic acid, methacrylic acid, vinyl acetic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid and mesaconic acid. Alternatively, dibasic acids are preferred. The amount of the carboxyl group-containing vinyl monomer used is 5 based on the total amount of the hydroxyl group-containing vinyl monomer, another copolymerizable vinyl monomer and the carboxyl group-containing vinyl monomer (vinyl monomer mixture).
% Or less, preferably 0.2 to 2% by weight and 5
If it exceeds 5% by weight, water resistance, storage stability and the like are deteriorated.

(C) Modified Vinyl Copolymer The modified vinyl copolymer used as the vehicle main component in the present invention is obtained by copolymerizing the above CAB with the above vinyl monomer mixture. The copolymerization ratio of CAB and the vinyl monomer mixture can be changed depending on the composition of the vinyl monomer mixture to be used and the ratio thereof, but in general, based on the total amount of CAB and the vinyl monomer mixture, CAB5 75% by weight, preferably 10 to 50% by weight, more preferably 3
The vinyl monomer mixture may be added in an amount of 0 to 50% by weight, and the vinyl monomer mixture may be added in an amount of 95 to 25% by weight, preferably 90 to 50% by weight, and more preferably 70 to 50% by weight. If the content of CAB is less than 5% by weight, defects such as the above-mentioned acrylic enamel will occur, and the hardness, solvent resistance, chemical resistance, durability, etc. of the coating film will deteriorate.
If it is more than 5% by weight, the surface of the coated surface will be discolored, and the adhesion will tend to decrease.

The copolymerization of CAB and the above vinyl monomer mixture is advantageously carried out by a solution polymerization method in the presence of a radical polymerization initiator. Examples of the solvent that can be used in the solution polymerization include alkylbenzene derivatives such as benzene, toluene, and xylene; butyl acetate, ethyl acetate, propyl acetate, amyl acetate, methoxybutyl acetate, methyl acetoacetate, ethyl acetoacetate, and methyl cellosolve acetate. Acetate ester solvents such as cellosolve acetate, diethylene glycol monomethyl ether acetate, carbitol acetate; ether solvents such as dioxane, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone Examples include system solvents, which may be used alone or in combination of two or more. Also,
The polymerization temperature can be generally in the range of about 50 to about 200 ° C, preferably about 80 to about 150 ° C.

Among the radical polymerization initiators, organic peroxide type ones such as benzoyl peroxide,
Peroxide-based polymerization initiators such as lauroyl peroxide and dicumyl peroxide, and hydroperoxide-based polymerization initiators such as tert-butyl hydroperoxide and cumene hydroperoxide are preferably used, and
A ketone peroxide-based or perester-based polymerization initiator can also be used. These polymerization initiators are added singly or in combination of two or more kinds to the polymerization reaction system.
Furthermore, in addition to the above-mentioned peroxides, hydroperoxides, etc., an azo-based polymerization initiator such as azobisiso-butyronitrile may be used in combination. Benzoyl peroxide is particularly preferable. In the copolymerization reaction using the organic peroxide as a polymerization initiator as described above, generally, the free radicals of the organic compound generated by thermal decomposition of these polymerization initiators cause a so-called chain transfer agent in the hydrocarbon compound. It is believed that the free radical generated on the hydrocarbon compound initiates the polymerization of the vinyl monomer and the vinyl compound grows in the hydrocarbon compound in a branched form to form a graft copolymer. Even in the copolymerization of the present invention using CAB and a vinyl monomer mixture, it is considered that a graft copolymer of CAB and a vinyl monomer mixture is formed by such a reaction mechanism.

The modified vinyl-based copolymer thus formed, that is, the CAB graft copolymer is remarkably excellent in solubility in an organic solvent and compatibility with other resins. In the present invention, it is desirable that substantially all of the blended CAB is copolymerized with the vinyl monomer mixture, but a small amount of the CAB and / or vinyl monomer mixture remains unreacted, and the copolymer is not reacted. There is no problem even if it remains inside.

[III] Polyisocyanate Compound The polyisocyanate compound has a function of crosslinking and curing the hydroxyl group-containing copolymer and the modified vinyl copolymer. The [III] polyisocyanate compound in the present invention is
In particular, non-yellowing type polyisocyanate compounds are preferable in terms of weather resistance, for example, aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexamethylene diisocyanate, organic diisocyanates themselves such as cyclic aliphatic diisocyanates such as xylylene diisocyanate or isophorone diisocyanate. Or an adduct of each of these organic diisocyanates with a polyhydric alcohol, a low molecular weight polyester resin, water or the like, a polymer of each of the organic diisocyanates mentioned above, and further an isocyanate burette. Typical examples of these commercially available products include "Bernock DN-950 and Dono-980" (all manufactured by Dainippon Ink and Chemicals, Inc.) and "Sumijour N-".
3200, same-3500, death module Z-437
0 "(Product of Sumitomo Bayer Urethane Co., Ltd.)," Duranate 24A-90CX, TPA-100 "(Product of Asahi Kasei Corporation)," Takenate D-110N, Dome-1 "
40N "(product of Takeda Pharmaceutical Co., Ltd.)," Coronate HL, EH "(product of Nippon Polyurethane Industry Co., Ltd.)
Etc.

The composition of the present invention contains the above-mentioned hydroxyl group-containing graft polymer, modified vinyl copolymer and the above polyisocyanate compound as essential components, and as a colorant, aluminum paste, pearl powder, graphite and MIO are used. , Organic and inorganic pigments, extender pigments, etc., and further contains additives such as acrylic polyol and paint additives such as UV absorbers, antioxidants, surface modifiers, dispersants, reaction accelerators, etc. May be included. In the composition of the present invention, the blending amount of the non-yellowing polyisocyanate compound is such that, when an additive resin such as a hydroxyl group and an acrylic polyol in the hydroxyl group-containing graft copolymer is further blended, the hydroxyl group of the resin is It is preferable to use an amount such that the equivalent ratio to the sum is within the range of NCO / OH = 0.5 to 2.0. The composition of the present invention thus obtained is generally used by mixing a main agent containing a hydroxyl group-containing graft copolymer and a modified vinyl copolymer and a curing agent containing a polyisocyanate compound immediately before coating. As the method for coating the composition of the present invention, spray coating, brush coating, roller coating and the like known in the coating coating field can be used, and usually a dry film thickness of about 10 to 80 μm, preferably about 20 to 50 μm is applied. The composition of the present invention, by containing a hydroxyl group-containing graft copolymer, a modified vinyl copolymer and a polyisocyanate compound, coating workability, the durability of the coating film is very excellent, especially in the field of automotive repair coatings. It is a very useful coating composition as a composition for a metallic base.

[0032]

EXAMPLES The present invention will be specifically described below with reference to examples.

Production of Hydroxyl Group-Containing Graft Copolymer Production Example 1 A reactor was equipped with a thermometer, a thermostat, a stirrer, a reflux condenser and a dropping pump, and 25 parts by weight of toluene and 43 parts by weight of xylene were charged and stirred. While 110
The temperature was raised to 0 ° C., and 101.2 parts by weight of a mixture of a monomer and a polymerization initiator shown in Table 2 below was added dropwise at 110 ° C. or less at a constant rate over 3 hours using a dropping pump. After completion of dropping, the temperature was kept at 110 ° C. for 60 minutes, and stirring was continued. afterwards,
A solution prepared by dissolving 0.5 parts by weight of azobisdimethylvaleronitrile as an additional catalyst in 10 parts by weight of xylene was added dropwise at a constant rate for 60 minutes. And 110 minutes after the dropping is completed
The reaction was terminated by keeping the temperature at 0 ° C. The obtained hydroxyl group-containing graft copolymer solution was a uniform and transparent solution having a nonvolatile content of 54.8% by weight and a Gardner viscosity Z ₂ . The weight average molecular weight of the copolymer was 32,400 the hydroxyl value was 82. Production Examples 2-3 and Comparative Production Example 4 In Production Example 1, a mixture of a monomer and a polymerization initiator,
And a hydroxyl group-containing copolymer solution was obtained in the same manner except that the additional catalyst had the composition shown in Table 2. Property values of the obtained copolymer solution and the copolymer are shown in Table 3.

[0034]

[Table 2]

[0035]

[Table 3]

Production of Modified Vinyl Copolymer Solution Production Example 5 The following components are charged in a reactor equipped with a thermometer, a stirrer, a reflux condenser and a dropping funnel. Toluol 30 parts by weight Butyl cellosolve acetate 20 parts by weight EAB-551-0.2 50 parts by weight (Eastman Kodak CAB) Total 100 parts by weight The above mixture is heated under a nitrogen gas atmosphere for about 1 hour. Heat to 100 ° C. 100 ° C, CAB
Was confirmed to be completely dissolved, the following mixture of vinyl monomer mixture and polymerization initiator was added to the CAB solution in an amount of 3
Drip over time. 2-Hydroxyethyl methacrylate 12 parts by weight Acrylic acid 1 part by weight Styrene 20 parts by weight Methyl methacrylate 20 parts by weight Methyl acrylate 47 parts by weight Xylol 50 parts by weight Benzoyl peroxide 2 parts by weight Total 152 parts by weight Azobis after 30 minutes from the end of dropping Add 0.5 parts by weight of isobutyronitrile, and then for 10 hours under nitrogen atmosphere for 10 hours.
Keep at 0 ℃, then add xylol, solid content 5
A 0 wt% modified vinyl copolymer solution A was obtained. The copolymer solution was colorless and transparent.

Example 1 54.8 obtained in Production Example 1
The modified vinyl-based copolymer 27.4 obtained in Production Example 5 was added to 16.9 parts by weight of the hydroxyl group-containing graft copolymer.
11.0 parts by weight of aluminum paste K-9800 (Asahi Kasei Metals), 10.7 parts by weight of xylol,
Toluol (24.0 parts by weight) and butyl acetate (10.0 parts by weight) were added, and the mixture was stirred with a disper for 20 minutes to prepare a metallic base.

[Examples 2 to 4, Comparative Examples 1 to 3] Metallic bases having the compositions shown in Table 4 were prepared in the same manner as in Example 1.

[0039]

[Table 4]

Duranate T as a curing agent was added to 100 parts by weight of the metallic bases of Examples 1 to 4 and Comparative Examples 1 to 3.
PA-100 (HMDI manufactured by Asahi Kasei Corporation) 8
After addition by weight, the mixture was diluted with a thinner having a composition of toluene / xylol / ethyl acetate / butyl acetate = 50/20/10/20 to 11 to 12 seconds (Ford cup # 4/25 ° C.) and viscous. Furthermore, as clear paint, PG
-80 SU Clear (manufactured by Kansai Paint Co., Ltd.) 10
After adding 10 parts by weight of Retan PG-80 curing agent (manufactured by Kansai Paint Co., Ltd.) to 0 parts by weight, a thinner having the above composition was used for 13 to 14 seconds (Ford Cup # 4/25).
(° C) and the viscosity was adjusted. As a finish evaluation coated plate, a commercially available lacquer primer surfacer (40 μm) was coated on a tin plate, dried at room temperature for 30 minutes, and then polished with # 400 water resistant polishing paper. The metallic base was spray-coated thereon to a dry film thickness of 30 μm, and the flicker unevenness was investigated. Further, after the metallic base was dried by touch to the touch, the above-mentioned clear was coated so as to have a dry film thickness of 40 μ and 80 μ, and the moduli unevenness was evaluated by comparing both coating films.
The results are shown in Table 5.

[0041]

[Table 5] (Note) Good △ Very uneven × Uneven surface

[0042]

INDUSTRIAL APPLICABILITY The present invention relates to a hydroxyl group-containing graft polymer and C
By containing the AB graft copolymer and the polyisocyanate, it is an excellent coating composition which does not cause flicker or moduli unevenness.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobushige Numa 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd.

Claims (6)

[Claims] 1. An [I] (a) macromonomer 10
To 30% by weight (b) 0 to 30% by weight of styrene, and (c) 40 to 90% by weight of another ethylenically unsaturated monomer, and a hydroxyl group-containing graft copolymer having a hydroxyl value of 60 to 120. [II] (a) Cellulose acetate butyrate 5-7
95 to 25% by weight of a vinyl monomer mixture comprising 5% by weight and (b) at least one 1 to 50% by weight of a functional vinyl monomer containing a hydroxyl group and 99 to 50% by weight of another copolymerizable vinyl monomer. % Of a modified vinyl copolymer obtained by copolymerizing the same and [III] polyisocyanate compound 2. The mixing ratio of [I] and [II] is [I] /
The coating composition according to claim 1, wherein [II] is in the range of 10/90 to 90/10. 3. The coating composition according to claim 1, wherein the graft polymer [I] has a weight average molecular weight of 10,000 to 60,000 and a glass transition temperature of 0 to 80 ° C. 4. The coating composition according to claim 1, wherein (a) the macromonomer is an oligomer or polymer having a polymerizable unsaturated group at the terminal. 5. (a) An oligomer or polymer having a terminal carboxyl group formed by polymerizing a radical-polymerizable monomer in the presence of a mercaptan chain transfer agent having a macromonomer having a carboxyl group, and an epoxy group at the terminal carboxyl group. The compound according to claim 1, which is obtained by reacting a compound having a polymerizable unsaturated group.
The coating composition described in the item. 6. The compounding amount of polyisocyanate is NCO / OH = 0.5 in an equivalent ratio to the sum of hydroxyl groups in the copolymer.
The coating composition according to any one of claims 1 to 5, which is 2 to 2.0.