JPH0528748B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a two-component urethane resin coating composition. More specifically, it is a two-component urethane containing an acrylic polyol that is useful for various uses such as paints and inks, and has a coating film with excellent drying properties, hardness, gloss, durability, weather resistance, and solvent resistance, and excellent workability. The present invention relates to a resin coating composition. (Prior Art) Conventionally, acrylic polyols, polyester polyols, oil-modified alkyd polyols, and the like are widely known as polyols used in two-component urethane resin paints. However, acrylic urethane resin paints using acrylic polyols have poor solvent dilutability and sprayability, and the resulting paint film has poor leveling during painting if dried quickly, and although it is glossy, it has poor durability. In addition, there are problems with solvent resistance in the early stage of curing and withering resistance during outdoor road conditions. In addition, urethane resin paints using polyester polyols or oil-modified alkyd polyols have good solvent dilutability and sprayability, and the resulting paint films have good gloss and durability, but they also have poor initial drying properties, chemical resistance, and outdoor road surface resistance. It has drawbacks such as contamination due to erosion. (Problems to be Solved by the Invention) As a result of intensive research to overcome these drawbacks, the present inventors have found that acrylic polyols containing cycloalkyl groups and specific functional groups have been developed for various uses such as paints and inks. In particular, the two-component urethane resin coating composition using this acrylic polyol and polyisocyanate compound has good solvent dilutability and sprayability, and the resulting coating film has a good balance between drying and leveling properties. The present inventors have discovered that they can form a coating film with good hardness, gloss, durability, weather resistance, solvent resistance, and gasoline resistance, and have completed the present invention. (Means and effects for solving the problems) That is, the present invention provides (1) 5.0 to 97.9% by weight of a polymerizable unsaturated monomer (a) containing a cycloalkyl group, a polymerizable unsaturated monomer containing a hydroxyl group; Monomer (b) 2.0 to 35.0% by weight, polymerizable unsaturated monomer containing acidic functional group (c) 0.1 to 5.0
Weight% and other polymerizable unsaturated monomers (d) 0.0
~92.9% by weight (however, the total of (a), (b), (c), and (d) is 100% by weight)) containing an acrylic polyol containing a cycloalkyl group. A two-component urethane coating composition comprising a hydroxyl group-containing compound and a polyisocyanate compound such that the hydroxyl groups in the hydroxyl group-containing compound and the isocyanate groups in the polyisocyanate compound are approximately the same in terms of compound stoichiometry. It is related to. The polymerizable unsaturated monomer (a) containing a cycloalkyl group used in the present invention improves the hardness, gloss, durability, solvent resistance, and gasoline resistance of the two-component urethane resin coating composition. , is an essential component for improving weather resistance, etc. Examples of the polymerizable unsaturated monomer (a) containing a cycloalkyl group include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate. One or more of these can be used. The monomer (a) is used in an amount of 5.0 to 97.9% by weight. If it is less than 5.0% by weight, the hardness, gloss, durability, solvent resistance, gasoline resistance,
If performance such as weather resistance is not sufficiently exhibited, and on the other hand, if a large amount exceeding 97.9% by weight is used, it becomes difficult to achieve both drying properties and leveling properties, which is not preferable. Examples of the polymerizable unsaturated monomer (b) containing a hydroxyl group used in the present invention include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, caprolactone-modified hydroxy (meth)acrylate (for example, trade name Plaxel FM (manufactured by Daicel Chemical Industries, Ltd.), mono(meth)acrylate of polyester diol obtained from phthalic acid and propylene glycol, mono(meth)acrylate of polyester diol obtained from succinic acid and propylene glycol, etc. Examples include (meth)acrylic monomers having the following, and one or more of these can be used. The polymerizable monomer (b) containing hydroxylation is an essential component for the reaction between the obtained acrylic polyol and polyisocyanate,
It is used in a range of 2.0 to 35.0% by weight, preferably 3.5 to 23.0% by weight. If it is less than 2.0% by weight, the amount of active hydrogen in the resulting acrylic polyol will decrease, and the amount of the isocyanate group-containing compound in the crosslinking agent used will also decrease, resulting in a crosslinking density that is too low and will not be able to achieve the desired coating film. Performance cannot be obtained. vice versa
If the amount exceeds 35% by weight, the stability with the crosslinking agent will deteriorate. Examples of the polymerizable unsaturated monomer (c) containing an acidic functional group used in the present invention include carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and maleic anhydride. Unsaturated monomers; unsaturated monomers containing sulfonic acid groups such as vinyl sulfonic acid, styrene sulfonic acid and sulfoethyl (meth)acrylate; 2-
(Meth)acryloyloxyethyl acid phosphate, 2-(meth)acryloyloxypropyl acid phosphate, 2-(meth)acryloyloxy-3-chloro-propyl acid phosphate, 2-methacryloyloxyethyl phenyl phosphate Examples include acidic phosphate unsaturated monomers such as acids, and one or more selected from these groups can be used. The monomer (c) acts as an internal catalyst for the reaction between the hydroxyl group in the acrylic polyol and the isocyanate in the polyisocyanate compound, and has a concentration of 0.1
Use in the range of ~5.0% by weight. If it is less than 0.1% by weight, it has no effect on drying properties when the resulting acrylic polyol is used as a two-component urethane resin paint, and when trying to speed up drying, it promotes the reaction between hydroxyl groups and isocyanate groups. A large amount of external catalyst is required for this purpose, and in this case, stability with the polyisocyanate compound is poor and painting workability is significantly impaired. On the other hand, if it is used in an amount exceeding 5.0% by weight, the reaction between hydroxyl groups and isocyanate groups will be significantly accelerated, resulting in poor stability and poor coating workability, as in the case of extensive use of external catalysts. Other polymerizable unsaturated monomers (d) used in the present invention include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, and butyl (meth)acrylate. (meth)acrylic acid alkyl esters such as acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate; glycidyl (meth)acrylate Epoxy group-containing unsaturated monomers such as (meth)acrylamide, N,N'-
Nitrogen-containing unsaturated monomers such as dimethylaminoethyl (meth)acrylate, vinylpyridine, vinyl imidasol; halogen-containing unsaturated monomers such as vinyl chloride and vinylidene chloride; styrene, α-
Aromatic unsaturated monomers such as methylstyrene and vinyltoluene; vinyl esters such as vinyl acetate;
Vinyl ethers; examples include unsaturated cyanide compounds such as (meth)acrylonitrile;
One or more types selected from these groups can be used. Other polymerizable unsaturated monomers
(d) is used as necessary within a range that does not impair the characteristics of the acrylic polyol for two-component urethane resin coatings of the present invention, and the amount used can be 0 to 92.9% by weight. The acrylic polyol used in the present invention includes the above-mentioned cycloalkyl group-containing polymerizable unsaturated monomer (a) and hydroxyl group-containing polymerizable unsaturated monomer (a).
(b), polymerizable unsaturated monomer containing acidic functional group (c)
It can be produced by polymerizing and other polymerizable monomers (d) using conventionally known polymerization methods. For example, solvents that can be used when employing the solution polymerization method include toluene, xylene, and other high-boiling aromatic solvents; ester solvents such as ethyl acetate, butyl acetate, and cellosolve acetate; methyl ethyl ketone, methyl isobutyl ketone For example, ketone solvents such as these can be used, and one or a mixture of two or more of these can be used. In addition, as a polymerization initiator, azobisisobutylnitrile, benzoyl peroxide, di-tert-
Usual radical polymerization initiators such as butyl peroxide can be mentioned. The reaction temperature is room temperature to 200℃, preferably 40 to 120℃
℃ range. In addition, the polyisocyanate compounds constituting the two-component urethane resin coating composition of the present invention include:
There is no particular restriction as long as it has two or more isocyanate groups, and examples include polyisocyanates such as trimethylene diisocyanate, 1,6-hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate. The amount of isocyanate groups in the compound is approximately the same stoichiometrically as the amount of hydroxyl groups in the acrylic polyol, preferably 0.7 to 1.4 equivalents (-
NCO/-OH). Too much of either of them is not preferable since the crosslinking reaction cannot be balanced, resulting in poor drying properties, hardness and solvent resistance of the coating film. Furthermore, the two-component urethane resin coating composition of the present invention can be prepared using a known catalyst (for example, an organic tin compound such as di-n-butyltin dilaurate or a tertiary It may contain various paint additives such as amines), organic solvents, fillers, leveling agents, plasticizers, stabilizers, dyes, and pigments. (Effect of the invention) The two-component urethane resin coating composition of the present invention provides a coating film with excellent drying properties, hardness, gloss, durability, weather resistance, and solvent resistance, and has excellent coating workability. It can be used for a wide range of applications such as large structures, automobile repair, and woodworking such as furniture painting. (Example) The present invention will be described below with reference examples and examples. In addition, parts or % in the examples are parts by weight or % by weight, respectively, unless otherwise specified. Example 1 Toluene was added to a four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube under a nitrogen gas stream.
25 parts of tert-butyl cyclohexyl methacrylate, 9 parts of hydroxyethyl methacrylate, 5 parts of styrene, 10 parts of methyl methacrylate, 5.5 parts of butyl acrylate, and 5 parts of butyl methacrylate were charged. A mixture of 0.5 parts of methacrylic acid and 0.5 parts of azobisisobutylnitrile was added dropwise over 2 hours, and the mixture was further maintained at 100°C for 4 hours to reduce the non-volatile content of the acrylic polyol of the present invention to 50.2 parts.
% and a viscosity of U to V (hereinafter referred to as acrylic polyol solution (1)). Examples 2-3, Comparative Examples 1-3 The same operations as in Example 1 were repeated except that the compositions of the polymerizable unsaturated monomer and polymerization initiator used were as shown in Table 1. Polyol solutions (2) to (3) and comparative polyols (1) to (3) were obtained.

[Table] Examples 4 to 6 and Comparative Examples 4 to 5 Acrylic polyol solutions (1) to (3) obtained in Examples 1 to 3 and Comparative Examples 1 to 2 and comparative polyol solutions (1) to (2) ) was blended with titanium oxide (Tiepeque R-820, manufactured by Ishihara Sangyo Co., Ltd.) so that the pigment concentration in nonvolatile matter was 40% by weight, and well dispersed with a sand mill. For each of the obtained dispersion liquids (hereinafter referred to as liquids), a polyfunctional isocyanate (Sumiyur N, Sumitomo Bayer Urethane Co., Ltd.) was added.
A liquid was prepared by weighing out an amount of the same amount of the isocyanate group equivalent to the hydroxyl group in the liquid as 1:1. These liquids are mixed and further diluted with a thinner of toluene:butyl acetate=1:1 to a viscosity that allows air spraying. ) to (3) and comparative paints (1) to (2) were obtained. Then, after painting the zinc phosphate treated board with air spray to a dry film thickness of 40μ, it was heated at 60℃.
Test pieces for various performance tests were prepared by force drying for 30 minutes. Comparative Example 6 Melamine resin (Cymel 303, manufactured by Mitsui Cyanamid Co., Ltd.; hexamethoxymethylolmelamine) was added to 100 parts of the comparative polyol (3) obtained in Comparative Example 3.
The same titanium oxide as in Example 4 was added to a resin solution containing 16.7 parts so that the pigment concentration in nonvolatile matter was 40% by weight, and the mixture was well dispersed with a sand mill. One part of a 50% n-butanol solution of para-toluenesulfonic acid was added to the resulting dispersion, and the mixture was diluted with xylene/n-butanol = 2/1 thinner to a sprayable viscosity to obtain a comparative paint (3 ) was obtained. Then air spray the zinc phosphate treated steel plate to a dry film thickness.
After coating to a thickness of 40μ, it was force-dried at 150°C for 40 minutes to prepare a test piece. The performance of the coating film was evaluated in four stages from ◎ to ○ to △ to × except for pencil hardness using the performance test method shown below.
The evaluation results are shown in Table 2. <Performance test method> Solvent dilutability: Judged by the degree of ease of dilution with thinner. Spray workability: Judged by workability during spraying. Drying property: Judgment using finger pressure and masking test immediately after forced drying. Finish appearance: Visual judgment of paint film. Gloss: Comparison of 60 degree specular reflectance measurements. Adhesion: Judged by adhesion to the painted base material. Pencil hardness: Scratch hardness at Mitsubishi Uni. Solvent resistance: Judging by observing the appearance after rubbing with urethane thinner. Weather resistance: Evaluation based on gloss retention after being exposed to outdoor conditions.

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Claims (1)

[Scope of Claims] 1. 5.0 to 97.9% by weight of a polymerizable unsaturated monomer (a) having a cycloalkyl group, and 2.0 to 97.9% by weight of a polymerizable unsaturated monomer (b) having a hydroxyl group.
35% by weight, polymerizable unsaturated monomer (c) containing acidic functional groups
0.1 to 5.0% by weight and 0.0 to 92.9% by weight of other polymerizable unsaturated monomers (d) (however, the total of (a), (b), (c) and (d) is 100% by weight). ) A hydroxyl group-containing compound and a polyisocyanate compound comprising an acrylic polyol containing a cycloalkyl group obtained by copolymerizing A two-component urethane resin coating composition which is blended in approximately the same amount as