JP2773129B2 - 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, for example, to abrasion resistance as a top coat in painting an automobile body. A resin composition for coatings that can be used for clear top coatings, etc., which has excellent glass transition temperature ranges in the presence of a high molecular weight azo initiator having a specific chemical structure.
An ethylenically unsaturated monomer (also referred to as a vinyl monomer)
And then, in the presence of the specific azo group-containing polymer thus obtained, further polymerize a vinyl monomer in a region having a different glass transition temperature with a specific block copolymer prepared by a novel method. And a specific curing agent as an essential component.

[Conventional technology]

As a coating for an automobile body, 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 is baked at the same time or dried at room temperature at the same time to form a cured coating film. So-called 2 coats 1 to get
A baking type coating method is widely used.

Recently, as one trend in automotive painting,
Although there is a trend in which dark solid color paint and dark metallic paint are preferred, the scratches caused by the car washing machine, that is, "car wash scratches", are higher than white solid color paint and light metallic paint. Is very conspicuous, and there is a strong demand for the appearance of a paint which gives a coating having excellent scratch-preventing ability in a machine car wash, that is, a scratch-resistant coating.

[Problems to be solved by the invention]

Thus, as long as you follow the conventional technology,
It has been extremely difficult to obtain an extremely practical resin composition for coatings that gives a coating film having excellent scratch-preventing ability, that is, excellent scratch resistance.

Therefore, the problem to be solved by the present invention is, on the one hand, to provide, in particular, a highly practical resin composition for coatings having excellent scratch resistance and the like.

Therefore, the present inventors considered the actual situation in the industry as described above, and aimed at the problems to be solved by the invention as described above, first, a valuable paint having excellent scratch resistance and the like. As a result of earnest and repeated studies, here, in the presence of an azo group-containing vinyl polymer obtained using a polymer azo initiator having a specific structure,
The present invention has been completed by finding that a coating material satisfying such requirements can be obtained by polymerizing vinyl monomers having different glass transition temperature ranges.

[Problems to be solved by the invention]

That is, the present invention provides, as an essential component, a general formula (However, in the formula, R ₁ represents an alkylene group, or an alkylene group containing either a benzene ring or a cyclohexane ring or an alkylene group containing an amide bond, and R ₂ contains an alkylene group or a cyano group. It represents an alkylene group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group, and n is an integer of 2 or more. An α, β-ethylenically unsaturated monomer having a glass transition temperature of less than 0 ° C. in the presence of 2 to 50% by weight of a compound (a-1-1) having a repeating unit represented by the following formula: (A-
1-2) by 10 to 49% by weight, and 1 to 77% by weight of an α, β-ethylenically unsaturated monomer (a-1-3) having a glass transition temperature of a homopolymer of 0 ° C. or more and less than 60 ° C. %, And then, in the presence of the azo group-containing polymer (a-1) thus obtained, an α, β-ethylenically unsaturated monomer (having a glass transition temperature of 60 ° C. or higher of the homopolymer) a-1-4) 10 ~
49% by weight and 1 to 77% by weight of the monomer (a-1-3)
And / or 2 to 50% by weight of the block copolymer (A-1) and / or the compound (a-1-1) obtained by polymerizing
In the presence of 10 to 49% by weight of the monomer (a-1-4)
And 1 to 77% by weight of the monomer (a-1-3), and then the azo group-containing polymer (a
In the presence of -2), 10 to 49 of the monomer (a-1-2)
% By weight and a block copolymer (A-2) obtained by polymerizing 1 to 77% by weight of the monomer (a-1-3);
An extremely practical resin composition for coatings comprising a polyisocyanate compound (B-1) or a block polyisocyanate compound (B-2) and / or an amino resin (B-3). It is assumed that.

Here, representative examples of the compound (a-1-1) having a repetition represented by the above-mentioned general formula [I] include azobiscyanopropanol, azobiscyano-n-butanol, azobiscyano-i -Butanol or azobiscyanopentanol, or "VA-08
0, VA-082 or VA-086 "(product of Wako Pure Chemical Industries, Ltd.), a compound having one diazo bond and two or more hydroxyl groups in one molecule, isophorone diisocyanate, methylcyclohexane -2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate,
4,4'-methylenebis (cyclohexylisocyanate), 1,3-di (isocyanatomethyl) cyclohexane, 1,4-di (isocyanatomethyl) cyclohexane, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tolylene diisocyanate or Examples thereof include a reaction product with a diisocyanate compound such as xylene diisocyanate, and for example, those having a structural unit represented by the following formula [II] or [III].

[However, n in the formula is an integer of 2 or more. ] [However, n in the formula is an integer of 2 or more. With respect to the compound (a-1-1), the range of the number of repeating units (n) in the above-mentioned general formula [I] is not particularly limited. Is preferably in the range of about 200.

The amount of the compound (a-1-1) used is suitably in the range of 2 to 50% by weight.

When the amount is less than 2% by weight, the coating workability at the time of coating is extremely reduced. On the other hand, when it exceeds 50% by weight, the abrasion resistance of the coating film is reduced. Is not preferred.

Then, α, at which the glass transition temperature becomes less than 0 ° C.,
As the β-ethylenically unsaturated monomer (a-1-2),
Representative examples include 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, β-hydroxyethyl acrylate, β-hydroxypropyl acrylate, and di-n-butyl fumarate. These are used in preparing the block copolymer (A-1) or (A-2), respectively. Among them, first, in preparing the block copolymer (A-1), First, it is used as an essential monomer component in the step of obtaining the azo group-containing polymer (a-1). On the other hand, in preparing the block copolymer (A-2), Used in the step of polymerizing in the presence of the azo group-containing polymer (a-2) And the monomer (a-
In any case, the usage amount of 1-2) is as follows.
The range of 10 to 49% by weight is appropriate.

Examples of the α, β-ethylenically unsaturated monomer (a-1-3) having a glass transition temperature of 0 ° C. or more and less than 60 ° C. include methyl acrylate, n-butyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, Typical examples are β-methylglycidyl methacrylate, dimethylaminoethyl methacrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl methacrylate, mono (methacryloyloxyethyl) acid phosphate, vinyl acetate and di-i-butyl fumarate. These are respectively used in preparing the block copolymer (A-1) or (A-2), and in preparing the block copolymer (A-1), the azo group-containing polymer is used. A step of obtaining a polymer (a-1), and subsequently, the polymer In both the step of performing a polymerization reaction in the presence of a-1) and the preparation of the block copolymer (A-2), the azo group-containing polymer (a-2) is obtained. It is used in both the step and the step of subsequently performing a polymerization reaction in the presence of the polymer (a-2). The amount of the monomer (a-1-3) used is In each case, 1 to 77% by weight
It is appropriate within the range.

Further, when the glass transition temperature is 60 ° C. or more,
As the β-ethylenically unsaturated monomer (a-1-4),
Acrylic acid, methacrylic acid, methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, itaconic acid, maleic acid,
Representative examples include fumaric acid and acrylonitrile, each of which is a block copolymer (A-
1) or (A-2), which is used in the step of obtaining the azo group-containing polymer (a-2) in preparing the block copolymer (A-2). On the other hand, the block copolymer (A-
In preparing 1), the azo group-containing polymer (a-
The monomer (a-1-4) is used in the step of carrying out the polymerization reaction in the presence of 1), and in any case, the range of 10 to 49% by weight is appropriate.

Here, the above-mentioned "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 the compound (a-1-1) to an organic solvent in advance. And then dissolved in the monomer (a-1-
A method of dropping a mixture of 2) and (a-1-3) or a mixture of the monomers (a-1-3) and (a-1-4) as described above, and a method of adding the compound (a −
In the system where 1-1) is present, these monomers (a-1-
2) and a method of dropping a mixture of (a-1-3) or a mixture of monomers (a-1-3) and (a-1-4), or the compound (a-1- 1)
And these monomers (a-1-2) and (a-1-3)
Or the monomers (a-1-3) and (a-
This method refers to a method in which the mixture of 1-4) is charged at the so-called initial stage of the polymerization reaction and the reaction is performed, and it goes without saying that the method can be freely selected from these various methods. No.

In addition, any polymerization reaction performed in preparing the block copolymer (A-1) or (A-2), which is one essential component of the resin composition for a coating material of the present invention, has a polymerization temperature of 60 to 60. A range of 140 ° C. is suitable for a polymerization time of about 6 to 15 hours.

Next, the above-mentioned polyisocyanate compound (B-1), which is another essential component of the coating resin composition of the present invention,
Representative examples of the blocked isocyanate compound (B-2) or the amino resin (B-3) are as follows.

First, as the compound (B-1), aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate or xylene diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate or trimethylhexane diisocyanate; or isophorone diisocyanate, methylcyclohexane-2 , 4-
Alicyclic diisocyanates such as diisocyanate, methylcyclohexane-2,6-diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate) or 1,3-di (isocyanatomethyl) cyclohexane, each of these diisocyanate compounds and ethylene glycol; Having a functional group capable of reacting with a polyhydric alcohol such as propylene glycol or trimethylolpropane, or an isocyanate group;
An extremely low molecular weight polyester compound having a number average molecular weight of about 2,000 (including oil-modified type)
And the like.

Next, as the compound (B-2), various polyisocyanate compounds (B-1) as described above are used, for example, by using (alkyl) such as phenol or cresol.
Typical examples are those blocked with a compound containing active hydrogen such as phenols, aromatic secondary amines, tertiary alcohols, lactams or oximes.

In addition, as a compound (B-2), as a dissociation catalyst (dissociation accelerator), it is a matter of course that a known and commonly used organotin compound can be used.

And these polyisocyanate compounds (B-1)
Or of the blocked isocyanate compound (B-2)
The amount used for the above-mentioned block copolymer (A-1) and / or (A-2) is suitably in a range where the ratio of the hydroxyl group equivalent to the isocyanate group equivalent is 1: 1.2 to 1: 0.8.

Further, as the resin _{(B-3), C 1} ~C 4 comprising monohydric alcohol etherified melamine resins, acetoguanamine resins and benzoguanamine resins or urea resins are typical, weather resistance, etc. In view of the above, use of a melamine resin is preferable, and particularly, use of an n-butyl etherified melamine resin is preferable.

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

When the resin (B-3) is cured, as a curing aid (curing accelerator), for example, paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, or an amine-blocked product thereof is used. Needless to say, various kinds of catalysts and the like may be used.

The resin composition for a coating material of the present invention thus obtained is mainly used for a top coat in automotive body coating, but can also be used for a metal material such as an electric appliance, plastics or wood.

〔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 Compound (a-1-1)] In a reactor equipped with a stirrer, a thermometer, and a reflux condenser,
24.0 parts of azobiscyanopentanol, chloroform
28.0 parts and 0.015 part of di-n-butyltin dioctate were charged and cooled with ice. Next, 16.8 parts of hexamethylene diisocyanate was gradually added dropwise while paying attention to heat generation. After completion of the dropwise addition, the mixture was heated to 25 ° C., and the reaction was continued for 24 hours with stirring.

Thereafter, 10 parts of methanol was added, and the mixture was kept under stirring for 2 hours to complete the reaction.

After the reaction was completed, chloroform was removed by reducing the pressure in the system, the reaction product was transferred into a desiccator, and dried under reduced pressure for 24 hours to obtain the target compound.

This has a number average molecular weight of 6,100 in terms of polystyrene by gel permeation chromatography, and is therefore known to have an average of 14.2 azo groups in one molecule.

Reference Example (same as above) In the same reactor as in Reference Example 1, 18.6 parts of azobiscyanopentanol, 62.7 parts of methyl ethyl ketone and di-
0.015 parts of n-butyltin dioctate was charged and cooled with ice. Then 22.2 of isophorone diisocyanate
The mixture was gradually dropped while paying attention to heat generation. After dropping,
The reaction was warmed to 25 ° C. and allowed to continue under stirring for 2 hours.

Thus, the number average molecular weight determined by gel permeation chromatography in terms of polystyrene was 7,900, and therefore, the average number of azo groups in one molecule was 17.
As a result, 40.1% of nonvolatile solutions of 9 target compounds were obtained.

Reference Examples 3 and 4 (same as above) Except that the compound having one diazo bond and two or more hydroxyl groups in one molecule and the diisocyanate compound were changed to be used in the composition shown in Table 1 In the same manner as in Reference Example 1, the target compound was obtained.

Reference Examples 5 to 9 (same as above) Except that a compound having one azo group and two or more hydroxyl groups in one molecule and a diisocyanate compound were changed to be used in the composition shown in Table 1 ,
The target compound was obtained in the same manner as in Reference Example 2.

Reference Example 10 [Preparation Example of Block Copolymer (A-1)] 10 parts of the compound (ab-1) obtained in Reference Example 1, 20 parts of lauryl methacrylate, and
10 parts, 70 parts of toluene and 30 parts of N-methylpyrrolidone
A reactor equipped with a stirrer, a thermometer, and a reflux condenser was heated to 80 ° C. while stirring, and kept at the same temperature for 3 hours.

Next, a mixture of 18 parts of methyl methacrylate, 20 parts of styrene, 20 parts of β-hydroxy methacrylate and 2 parts of acrylic acid was added dropwise thereto over 2 hours. After the completion of the dropwise addition, the polymerization reaction was continued at the same temperature for 24 hours under stirring.

The target copolymer thus obtained has a non-volatile content of 50.0%, and has a polystyrene equivalent number average molecular weight of 18,000 as determined by gel permeation chromatography.
It was something.

Reference Examples 11 to 20 [Preparation Example of Block Copolymer (A-1) or (A-2)] Compound (a-1-1) as shown in Table 2 and two groups of α, β- A target copolymer (A-1) or (A-2) was obtained in the same manner as in Reference Example 10, except that an ethylenically unsaturated monomer was used.

Reference Example 21 [Preparation Example of Control Random Copolymer (A ')] A reactor equipped with a stirrer, a thermometer and a reflux condenser charged with 63 parts of toluene and 27 parts of N-methylpyrrolidone was stirred. While heating to 110 ° 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 and 2 parts of acrylic acid and 1.0 part of azobisisobutyronitrile was added dropwise over 5 hours, and after completion of the addition, the mixture was stirred at the same temperature for 24 hours. The polymerization reaction was continued while maintaining the temperature.

Thus, the number average molecular weight determined by gel permeation chromatography in terms of polystyrene was 16,0
A control random copolymer solution having a nonvolatile content of 50.2% of the target copolymer of No. 00 was obtained.

Reference Examples 22 to 24 (same as above) Toluene / N-methylpyrrolidone =
Using a mixture of 70/30 (weight ratio), non-volatile content is 50%
The objective copolymer was prepared in the same manner as in Reference Example 21, except that the control block copolymer solution was changed to use an initiator and a vinyl monomer as shown in Table 3. Was obtained.

Example 1 of the block copolymer (A-1-1) obtained in Reference Example
To 50 parts, 17.9 parts of "Super Beckamine L-117-60" (n-butyl etherified melamine resin manufactured by Dainippon Ink and Chemicals, Ltd .; nonvolatile content = 60%) was mixed, and the mixture was mixed with methyl ethyl ketone and a Ford cup. In # 4, dilute the solution to 25 seconds, then apply it by air spraying, apply a metallic paint on the electrodeposition plate, which is usually coated with an intermediate paint used for automobiles, and then apply it. Was.

Then, after setting for 10 minutes,
Baking was performed at 140 ° C. for 25 minutes to obtain a cured coating film.

Examples 2 to 13 and Comparative Examples 1 to 6 Using a block copolymer or a random copolymer and a curing agent as shown in Table 4, and 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 above procedure was changed.

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 for the coating film obtained by curing according to 1), the coating was performed 72 hours after forced drying. The abrasion resistance was evaluated using a gauze containing a cleanser.
The gloss retention (%) after 30 rounds of rubbing at 1 kg was measured.

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

Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI C08G 18/63 C08G 18/63 Z (56) References JP-A-57-192353 (JP, A) JP-A-53-116323 (JP, A ) Patent Akira 53-117089 (JP, a) JP flat 1-138207 (JP, a) patent 2661119 (JP, B2) US Patent 3909497 (US, a) (58 ) investigated the field (Int.Cl. ⁶ , DB name) C09D 175/00-175/16 C08G 18/00-18/87

Claims (2)

(57) [Claims] (1) As an essential component, a general formula (However, in the formula, R ₁ represents an alkylene group, or an alkylene group containing either a benzene ring or a cyclohexane ring or an alkylene group containing an amide bond, and R ₂ contains an alkylene group or a cyano group. It represents an alkylene group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group, and n is an integer of 2 or more. An α, β-ethylenically unsaturated monomer having a glass transition temperature of less than 0 ° C. in the presence of 2 to 50% by weight of a compound (a-1-1) having a repeating unit represented by the following formula: (A-
1-2) by 10 to 49% by weight, and 1 to 77% by weight of an α, β-ethylenically unsaturated monomer (a-1-3) having a glass transition temperature of a homopolymer of 0 ° C. or more and less than 60 ° C. %, And then, in the presence of the azo group-containing polymer (a-1) thus obtained, an α, β-ethylenically unsaturated monomer (having a glass transition temperature of 60 ° C. or higher of the homopolymer) a-1-4) 10 ~
49% by weight and 1 to 77% by weight of the monomer (a-1-3)
And / or 2 to 50% by weight of the block copolymer (A-1) and / or the compound (a-1-1) obtained by polymerizing
In the presence of 10 to 49% by weight of the monomer (a-1-4)
And 1 to 77% by weight of the monomer (a-1-3), and then the azo group-containing polymer (a
In the presence of -2), 10 to 49 of the monomer (a-1-2)
% By weight and a block copolymer (A-2) obtained by polymerizing 1 to 77% by weight of the monomer (a-1-3);
A resin composition for a coating, comprising a polyisocyanate compound (B-1) or a block polyisocyanate compound (B-2) and / or an amino resin (B-3). 2. The above general formula (However, in the formula, R ₁ represents an alkylene group, or an alkylene group containing either a benzene ring or a cyclohexane ring or an alkylene group containing an amide bond, and R ₂ contains an alkylene group or a cyano group. It represents an alkylene group, an alkylene group containing an amide bond, or an alkylene group having both an amide bond and a hydroxyl group, and n is an integer of 2 or more. (A-1-1) having a repeating unit represented by the formula:
The composition according to claim 1, wherein the compound is obtained by reacting a compound having one azo group and two or more hydroxyl groups in one molecule with a diisocyanate compound.