JP3163443B2 - Resin composition for paint - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel and useful coating resin composition, and more particularly to, for example, an anti-reflective coating used as a top coat for painting an automobile body. A resin composition for coatings, such as a clear coating composition for top coating, which has excellent abrasion properties, and a glass transition temperature (hereinafter, referred to as Tg) in the presence of a polymer azo initiator having a specific chemical structure.
Abbreviated. ) An essential component comprising a block copolymer prepared by further polymerizing a vinyl monomer having a different Tg region onto an azo group-containing polymer obtained by polymerizing a vinyl monomer having a different region, and a curing agent. And a resin composition for paint.

[Problems to be solved by conventional technology and invention]

As a method of coating an automobile body, generally, a clear coat is applied by a wet-on-wet method on a base coat containing a coloring pigment and / or a metallic pigment, and the entire coating layer is simultaneously baked or cured at room temperature. The so-called two-coat, one-bake coating, which is called squeezing, is adopted and widely practiced.

In recent years, as solid-state paint, dark solid color paint and metallic paint have been particularly preferred and become popular.

Compared to white solid color paint and light color metallic paint, scratches caused by the car wash, that is, "car wash scratches" are very noticeable, and the ability to prevent scratches in mechanical car wash, that is, excellent scratch resistance The demand for coating films is increasing with the general public.

However, the present inventors have conducted intensive studies in order to find a resin composition for coating which provides excellent scratch-resistant coatings in accordance with the above-mentioned requirements of the industry, and as a result, the presence of the azo group-containing copolymer has been confirmed. The present invention is completed by finding that the purpose can be achieved by using a specific block copolymer obtained by polymerizing α, β-ethylenically unsaturated monomers having different Tg regions below. Reached.

[Means to solve the problem]

That is, the present invention uses, as an essential component, a general formula Compound (a-1-) having a repeating unit represented by
In the presence of 2 to 50% by weight of 1), 10 to 49% by weight of an α, β-ethylenically unsaturated monomer (a-1-2) whose glass transition temperature of the homopolymer is less than 0 ° C. Is obtained by polymerizing 1 to 77% by weight of an α, β-ethylenically unsaturated monomer (a-1-3) whose homopolymer has a glass transition temperature of 0 ° C. or more and less than 60 ° C. Group-containing polymer (a-
Α, β-ethylenically unsaturated monomer (a-1-4) whose homopolymer has a glass transition temperature of 60 ° C. or more in the presence of 1)
Of the monomer (a-1-3) and 10 to 49% by weight of
% By weight of a block copolymer (A)
-1) and / or 2- of the compound (a-1-1)
In the presence of 50% by weight, 10 to 10 of the monomer (a-1-4)
49% by weight and 1 to 77% by weight of the monomer (a-1-3)
Are polymerized, and then the monomer (a-1-2) is obtained in the presence of the azo group-containing polymer (a-2) thus obtained.
Of the monomer (a-1-3) and 10 to 49% by weight of
% By weight of a block copolymer (A)
-2) and a polyisocyanate compound (B-1) or a blocked isocyanate compound (B-2) and / or an amino resin (B-3). It is an object of the present invention to provide a resin composition for coatings to be provided.

Here, the compound (a-1-1) described above is
General formula A compound having a repeating unit represented by and having two or more azo groups and four or more ester bonds in one molecule, for example, a compound such as azobiscyanopentanoic acid chloride in one molecule A compound having one azo group and two acyl chloride groups, ethylene glycol,
Propylene glycol, dipropylene glycol, 1,4
-Butylene glycol, 1,3-butylene glycol, 1,6
-Hexanediol, polyethylene glycol, polypropylene glycol, neopentyl glycol, cyclohexanediol, trimethylolethane, trimethylolpropane, obtained by reaction with a polyol compound such as glycerin or pentaerythritol, for example, as shown below Is a compound having various repeating units.

Or With respect to the compound (a-1-1), the range of the number of repeating units (n) in the above general formula [I] is not particularly limited, but when the solubility in an organic solvent and the like are considered, , 200 is desirable.

The amount of the compound (a-1-1) used is appropriately in the range of 2 to 50% by weight, and when less than 2% by weight, the coating workability is extremely reduced. On the other hand, if the content exceeds 50% by weight, the abrasion resistance of the coating film will be reduced, which is not preferable.

Next, the α, β-ethylenically unsaturated monomer (a-1-2) in which the above-mentioned homopolymer has a glass transition temperature of less than 0 ° C.
As typical examples, ethyl acrylate,
n-butyl acrylate, isobutyl acrylate, 2
-Ethylhexyl acrylate, β-hydroxyethyl acrylate, β-hydroxypropyl acrylate, 2
-Ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate or di-n-butyl fumarate, and these are block copolymers (A
In preparing (-1) or (A-2), each is used as an essential monomer component. Among them, first, in preparing this block copolymer (A-1), Is used in the step of obtaining the azo group-containing polymer (a-1). On the other hand, in preparing the block copolymer (A-2), the azo group-containing polymer (a- It is used in the step of polymerizing in the presence of 2), and the amount of the monomer (a-1-2) used is in the range of 10 to 49% by weight in any case. is there.

Α, β-ethylenically unsaturated monomer (a-1-3) wherein the glass transition temperature of the homopolymer is less than 60 ° C.
As typical examples, methyl acrylate,
n-butyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, β-methylglycidyl methacrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl methacrylate, mono (methacryloyloxyethyl) acid phosphate, vinyl acetate or di-i-butyl fumarate Yes,
These are each used as an essential monomer component when preparing the block copolymer (A-1) or (A-2). Among them, the block copolymer (A-1) is used. In preparing the azo group-containing polymer (a-1) and the subsequent step of performing a polymerization reaction in the presence of the polymer (a-1), In preparing the block copolymer (A-2), a step of obtaining an azo group-containing polymer (a-2) and a subsequent polymerization in the presence of the polymer (a-2) The monomer (a-1-3) is used in both the step of carrying out the reaction and the amount of the monomer (a-1-3) is suitably in the range of 1 to 77% by weight in any case.

Further, the above-mentioned homopolymer has a glass transition temperature of 60 ° C.
The α, β-ethylenically unsaturated monomer (a-1-
Typical examples of 4) include acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, itaconic acid, maleic acid, fumaric acid, and acrylonitrile, each of which is a block. It is used for preparing the copolymer (A-1) or (A-2), and the block copolymer (A-
In preparing 2), the azo group-containing polymer (a-
On the other hand, in preparing the block copolymer (A-1), the polymerization is carried out in the presence of the azo group-containing polymer (a-1). The amount of the monomer (a-1-4) used is suitably in the range of 10 to 49% by weight in any case.

Here, the term "in the presence of the compound (a-1-1) having a repeating unit represented by the general formula [I]" means that the compound (a-1-1) is prepared by adding an organic solvent The mixture of the monomers (a-1-2) and (a-1-3) as described above, or the monomers (a-1-3) and (a-1-3) as described above, a-1-4) may be added dropwise to the compound (a-1-1) or a system in which the compound (a-1-1) is present.
A method of dropping a mixture of 1-2) and (a-1-3) or a mixture of these monomers (a-1-3) and (a-1-4), or in a batch. Compound (a-1-1) and these monomers (a-1-2)
And the mixture of (a-1-3) and the monomer (a-1)
-3) and a mixture of (a-1-4) are used at the so-called initial stage of the polymerization reaction, and the method is used to carry out such a polymerization reaction. Of course, it is possible to freely select from these various methods.

Further, the polymerization reaction carried out for preparing the block copolymer (A-1) or (A-2), which is an essential component of the resin composition for a coating material of the present invention, has a polymerization temperature of 60 to 60. A temperature within the range of 140 ° C. and a polymerization time of about 6 to 15 hours are suitable.

Next, the above-mentioned polyisocyanate compound (B-1), which is another essential component of the coating resin composition of the present invention,
As the blocked isocyanate compound (B-2) or the amino resin (B-3), the following compounds are typical.

First, as the compound (B-1), aromatic diisocyanate such as tolylene diisocyanate, diphenylmethane diisocyanate or xylene diisocyanate; or isophorone diisocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 4,4 Alicyclic diisocyanates such as' -methylenebis (cyclohexylisocyanate) or 1,3-di (isocyanatomethyl) cyclohexane, and these various diisocyanate compounds and various polyhydric alcohols such as ethylene glycol, propylene glycol or trimethylolpropane Or a class having an extremely low molecular weight having a number average molecular weight of about 500 to 2,000 having a functional group capable of reacting with an isocyanate group, for example. Such adducts of the polyester compound (including an oil-modified type.) Is one representative, then the compound (B-2) The various polyisocyanate compounds as being supra (B-
1) is blocked with various (alkyl) phenols such as phenol or cresol, and various so-called active hydrogen-containing compounds such as aromatic secondary amines, tertiary alcohols, lactams or oximes. The abusive ones are typical.

In addition, it is needless to say that a known and commonly used organotin compound or the like can be used as the dissociation catalyst (dissociation accelerator) for the compound (B-2).

And these polyisocyanate compounds (B-
1) or blocked isocyanate compound (B-2)
Is used in the above-mentioned block copolymer (A-
It is suitable that the equivalent ratio of the hydroxyl group / isocyanate group (OH / NCO) to 1) and / or (A-2) is in the range of 1 / 0.8 to 1 / 1.2.

Further, as the resin (B-3), a melamine resin, an acetoguanamine resin, a benzoguanamine resin or a urea resin etherified with a C _{1 to} C ₄ monohydric alcohol is a typical one. From the point of view,
The use of melamine resins is preferred, especially the use of n-butyl etherified melamine resins.

The amount of the resin (B-3) used may be the same as that of the block copolymer (A-1) and / or (A-
10) to 100 parts by weight, preferably 15 to 100 parts by weight of 2)
It is appropriate to be within the range of ~ 65 parts by weight.

Further, in curing the resin (B-3), para-toluenesulfonic acid, a curing aid (curing accelerator),
It is a matter of course that various known catalysts such as dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and amine-blocked products thereof may be used.

The resin composition for paints of the present invention is mainly used for a paint top coat of an automobile body, but can also be used for various plastics and woods, including metal materials in electric machine products and the like. .

〔Example〕

Next, the present invention will be described more specifically with reference examples, examples and comparative examples. In the following, all parts and percentages are by weight unless otherwise specified.

Reference Example 1 [Preparation Example of Polymer Azo Initiator (a-1-1)] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 118 parts of 1,6-hexanediol and 2,2 parts of chloroform were added.
000 parts and 202 parts of triethylamine were charged and cooled with ice, and 317 parts of azobiscyanopentanoic acid chloride were added thereto.
A solution in which 3,000 parts of chloroform was dissolved in 3,000 parts of chloroform was gradually dropped while paying attention to heat generation.

After completion of the dropwise addition, the reaction was continued under stirring at 35 ° C. for 2 hours, and then the reaction product was washed with ion-exchanged water and dried in a desiccator under reduced pressure for 24 hours.

The obtained product is a brown viscous liquid, which has a number average molecular weight of 1,800 in terms of polystyrene by gel permeation chromatography and an average number of azo groups in one molecule of 4.5. It was confirmed to be an initiator compound.

Reference Examples 2 to 4 (same as above) Instead of using 118 parts of 1,6-hexanediol, a polyol compound as shown in Table 1 was used in an amount as shown in the table, except that it was changed to be used. Various target initiator compounds were obtained in the same manner as in Reference Example 1. The property values of each compound are as shown in the same table.

Reference Example 5 [Preparation Example of Block Copolymer (A-1)] 10 parts of the polymer azo initiator obtained in Reference Example 1, 20 parts of lauryl methacrylate, and
10 parts, 70 parts of toluene and 30 parts of N-methylpyrrolidone
A reaction vessel equipped with a thermometer, a stirrer and a reflux condenser was heated to 80 ° C. while stirring and held for 3 hours, and then 18 parts of methyl methacrylate, 20 parts of styrene, β- Hydroxyethyl methacrylate 20
And a mixture of 2 parts of acrylic acid and 2 parts of acrylic acid were added dropwise over 2 hours, and after completion of the addition, the mixture was kept at the same temperature for 24 hours and polymerized with stirring.

The solution of the target polymer thus obtained had a nonvolatile content of 50.1
%, And the copolymer had a number average molecular weight of 15,200 in terms of polystyrene determined by gel permeation chromatography. Hereinafter, this is abbreviated as block copolymer (A-1-1).

Reference Examples 6 to 8 [Block copolymer (A-1) or (A
Preparation Example of -2)] The high-molecular-weight azo initiators as shown in Table 2 and the α, β-ethylenically unsaturated monomers belonging to the respective groups are used in the amounts as shown in Table 2 Various block copolymer solutions were obtained in the same manner as in Reference Example 5, except that the composition was changed so as to be used in Example 5. The properties of the respective copolymers and their solutions are as shown in the table.

Reference Example 9 [Preparation Example of Random Copolymer for Control] 63 parts of toluene and 27 parts of N-methylpyrrolidone were charged into a reaction vessel equipped with a thermometer, a stirrer and a reflux condenser, and stirred while stirring. ° C., 18 parts of methyl methacrylate, 20 parts of styrene, 10 parts of isobutyl methacrylate, 20 parts of lauryl methacrylate, β-
A mixture of 20 parts of hydroxyethyl methacrylate, 2 parts of acrylic acid and 1 part of azobisisobutyronitrile was added dropwise over 5 hours.

After the completion of the dropwise addition, the mixture was kept at the same temperature for 24 hours and polymerized under stirring.

The copolymer solution thus obtained has a nonvolatile content of 50.2%
And the gel permeation of the copolymer
The number average molecular weight in terms of polystyrene by chromatography was 16,000. Hereinafter, this is abbreviated as (A'-1).

Reference Examples 10 to 12 (same as above) Except that the initiator and the α, β-ethylenically unsaturated monomer as shown in Table 3 were changed to be used in the amounts used as shown in Table 3, Various random copolymer solutions were obtained in the same manner as in Reference Example 9. However, in this series, as in Reference Example 9, a mixed solvent of toluene: N-methylpyrrolidone = 70: 30 (weight ratio) was used as the polymerization solvent, and the obtained random copolymer solution was used. The nonvolatile content is designed to be 50%.

Example 1 50 parts of the block copolymer solution of the copolymer (A-1-1) obtained in Reference Example 5 was charged with "Super Beckamine L-
117-60 "[n-butyl etherified melamine resin manufactured by Dainippon Ink and Chemicals, Ltd .; nonvolatile content = 60%], and then mixed with methyl ethyl ketone in a Ford cup # 4 for 25 seconds. To prepare a coating.

Next, the paint was applied by air spraying, and a metallic paint was further applied and set on an electrodeposited plate which was previously coated with an intermediate paint commonly used in automobiles. Then, after setting for 10 minutes, baking was performed at 140 ° C. for 25 minutes to obtain a cured coating film.

Examples 2 to 6 and Comparative Examples 1 to 6 Using a block copolymer or a random copolymer and a curing agent as shown in Table 4, and under curing conditions or forced drying conditions as shown in the same table Various cured coating films were obtained in the same manner as in Example 1 except that the modification was performed.

The performance of each cured coating film obtained in each of the examples and comparative examples described above was evaluated in the following manner.

 The results are summarized in Table 4.

The evaluation of the coating film performance was performed using a polyisocyanate compound (B-
Only in the case of the coating film obtained by the curing according to 1), it was performed 72 hours after the forced drying. The abrasion resistance was evaluated using a gauze containing a cleanser under a load of 1 kg. This method is based on a method of measuring the gloss retention (%) after rubbing the cured coating film 30 times back and forth.

[Effects of the Invention] As is clear from Table 4, it is known that the coating resin composition of the present invention is particularly excellent in scratch resistance of the coating film.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Susumu Nagai 3-5-5 Fujishirodai, Suita-shi, Osaka A27-209 (72) Inventor Akira Ueda 7-1-25, Nishitoriishi, Takaishi-shi, Osaka (56) Reference Document JP-A-1-234472 (JP, A) JP-A-2-167375 (JP, A) JP-A-2-229873 (JP, A) JP-A-2-67381 (JP, A) JP-A-1- 254775 (JP, A) JP-A-1-254774 (JP, A) JP-A-1-252611 (JP, A) JP-A-1-245066 (JP, A) JP-A-1-230604 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 175/00-175/16 C09D 153/00 C09D 161/20-161/32 C08F 293/00 C08G 18/00-18/87 CA ( STN) REGISTRY (STN)

Claims (2)

(57) [Claims] (1) General formula Compound (a-1-) having a repeating unit represented by
In the presence of 2 to 50% by weight of 1), 10 to 49% by weight of an α, β-ethylenically unsaturated monomer (a-1-2) having a glass transition temperature of a single monomer of less than 0 ° C. And 1 to 77% by weight of an α, β-ethylenically unsaturated monomer (a-1-3) having a glass transition temperature of 0 ° C. or higher and lower than 60 ° C. of the homopolymer, and then obtained. Azo group-containing polymer (a-
Α, β-ethylenically unsaturated monomer (a-1-4) whose homopolymer has a glass transition temperature of 60 ° C. or more in the presence of 1)
Of the monomer (a-1-3) and 10 to 49% by weight of
% By weight of a block copolymer (A-
1) and / or 2 to 50 of the compound (a-1-1)
In the presence of 10% to 49% of the monomer (a-1-4) in the presence of
% By weight of the monomer (a-1-3) and 1 to 77% by weight of the monomer (a-1-3), and then the monomer (a-1-3) in the presence of the azo group-containing polymer (a-2) thus obtained. a-1-2)
A block copolymer (A-A) obtained by polymerizing 10 to 49% by weight and 1 to 77% by weight of the monomer (a-1-3).
2) and a polyisocyanate compound (B-1) or a blocked isocyanate compound (B-2) and / or
Alternatively, a resin composition for a paint, comprising an amino resin (B-3) as an essential component. 2. The above general formula Compound (a-1-) having a repeating unit represented by
The composition according to claim 1, wherein 1) is obtained by reacting a polyol having a compound having one azo group and two acyl chloride groups in one molecule with a polyol.