JPH06207142A - Composition for urethane resin coating - Google Patents

Abstract

PURPOSE:To obtain a composition for urethane resin coating having good gloss and apparent thickness, capable of forming a long-term weather resistant coating film excellent in gloss retaining property, discoloration resistance, crack resistance and blister resistance in long-term outdoor use without impairing physical and chemical properties such as solvent resistance and chemical resistance. CONSTITUTION:The composition for urethane resin coating contains an acrylic polyol obtained by copolymerizing a polymerizable monomer component consisting of (a) 0.1-10.0wt.% polymerizable ultraviolet ray stabilizing monomer, (b) 5.0-97.9wt.% polymerizable unsaturated monomer containing a crycloalkyl group, (c) 2.0-35.0wt.% polymerizable unsaturated monomer having hydroxyl group, (d) 0-10.0wt.% polymerizable ultraviolet ray-absorbing monomer and (e) 0-92.9wt.% other polymerizable unsaturated monomer [with the proviso that total amount of these components (a) to (e) is 100wt.%] and a polyisocyanate compound.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a urethane resin coating composition. More specifically, a urethane which contains an acrylic polyol useful for various applications such as paints and inks, and which forms a coating film which is particularly excellent in long-term weather resistance and is also excellent in drying property, hardness, luster, durability and solvent resistance. The present invention relates to a resin coating composition.

[0002]

2. Description of the Related Art Conventionally, a coating composition which is particularly required to have a beautiful appearance has 30% by weight to 60% by weight of an aromatic vinyl monomer from the viewpoint of gloss, fleshness and physical / chemical properties.
Compositions containing weight percent of the copolymer used have been commonly used. However, since a coating composition containing a copolymer containing a large amount of an aromatic unsaturated monomer has poor weather resistance, it has been improved by mixing and blending a known ultraviolet stabilizer or ultraviolet absorber. Recently, it has also been proposed to copolymerize an ultraviolet absorbing monomer (Japanese Patent Publication No. 61-42751). Although these are effective for improving the weather resistance to a certain level, they are not sufficient from the viewpoint of long-term weather resistance. On the other hand, a coating composition obtained by mixing and blending an ultraviolet absorber with a conventional copolymer obtained without using an aromatic unsaturated monomer or by copolymerizing an ultraviolet absorbing monomer has a long-term weather resistance. Although it has been improved considerably, the beautifulness such as gloss and fleshness was not sufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention has a good gloss and a long-lasting property, and is a gloss for outdoor use for a long period of time without deteriorating the physical and chemical properties such as solvent resistance and chemical resistance. An object of the present invention is to provide a composition for urethane resin coatings capable of forming a long-term weather-resistant coating film excellent in retention, discoloration resistance, crack resistance, blister resistance, and the like.

[0004]

Means for Solving the Problems That is, the present invention provides a polymerizable ultraviolet-stable monomer (a) 0.1 to 10.0% by weight, a polymerizable unsaturated monomer containing a cycloalkyl group (b) 5.0 to 97.9.
% By weight, and 2.0% of the polymerizable unsaturated monomer (c) having a hydroxyl group.
~ 35.0% by weight, polymerizable UV absorbing monomer (d) 0 ~ 10.0
% By weight and other copolymerizable polymerizable unsaturated monomer (e)
Polymerizable monomer component consisting of 0 to 92.9% by weight (however, (a),
The sum of (b), (c), (d) and (e) is 100% by weight. And a polyisocyanate compound, and a urethane resin coating composition containing a polyisocyanate compound.

[0005]

The inventors of the present invention have conducted extensive studies to overcome the above-mentioned problems of the prior art, and as a result, an acrylic polyol of a specific composition having a cycloalkyl group and an ultraviolet stable group was used as a paint,
It exhibits useful properties for various uses such as ink, and in particular, a urethane resin coating composition using the acrylic polyol and a polyisocyanate compound has good gloss and longevity, and physical properties such as solvent resistance and chemical resistance. And, without losing the chemical properties, gloss retention in long-term outdoor use,
The inventors have found that a coating film with long-term weather resistance, in which discoloration resistance, crack resistance, blistering resistance, etc. are remarkably improved, is formed, and have completed the present invention.

In the present invention, a polymerizable UV stable monomer
(a) is used in the range of 0.1 to 10.0% by weight in the polymerizable monomer component, but if it is less than 0.1% by weight, the weather resistance is not sufficiently exerted, and conversely, it is used in a large amount exceeding 10.0% by weight. If it is, the luster and fleshness will deteriorate and the appearance will be impaired.
It is preferably used in the range of 0.2 to 5.0% by weight. The polymerizable UV-stable monomer (a) is not particularly limited as long as it has at least one piperidinyl group having a sterically hindered nitrogen atom and a polymerizable unsaturated group in the molecule, In particular, the following general formulas (I) and (II)

[0007]

[Chemical 3]

[0008]

[Chemical 4] (However, in the general formulas (I) and (II), R ₁ is a hydrogen atom or a cyano group, R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R ₄ is hydrogen. An atom or an alkyl group having 1 to 18 carbon atoms, and X represents an imino group or an oxygen atom.)

The compound represented by the formula (1) is effective for obtaining an acrylic polyol having further excellent weather resistance.

Examples of the compounds represented by the general formulas (I) and (II) include 4- (meth) acryloyloxy-2,2,6,
6-Tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-
(Meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,
2,6,6-Pentamethylpiperidine, 4-cyano-4-
(Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth)
Acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyl Oxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-
Examples thereof include tetramethylpiperidine and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine.

The polymerizable unsaturated monomer (b) containing a cycloalkyl group used in the present invention is a coating film of a urethane resin coating composition having a hardness, gloss, durability, solvent resistance and gasoline resistance. It is an essential component for improving the properties and weather resistance. Examples of the polymerizable unsaturated monomer (b) containing a cycloalkyl group include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, tertiary butylcyclohexyl (meth) acrylate and cyclododecyl (meth) acrylate. And one or more of these can be used. The monomer (b) is used in the range of 5.0 to 97.9% by weight in the polymerizable monomer component. If it is less than 5.0% by weight, the coating film does not exhibit sufficient performance such as hardness, gloss, fleshness and weather resistance. Conversely, if it is used in excess of 97.9% by weight, it is dry and leveling. It is not preferable because it becomes difficult to satisfy both.

Examples of the polymerizable unsaturated monomer (c) having a hydroxyl group used in the present invention include, for example, hydroxyethyl (meth) acrylate and hydroxypropyl (meth).
Acrylate, caprolactone-modified hydroxy (meth)
Acrylate (eg, trade name Praxel FM, manufactured by Daicel Chemical Industries, Ltd.), polyester diol mono (meth) obtained from phthalic acid and propylene glycol
Examples thereof include (meth) acrylic monomers having a hydroxyl group such as acrylate, and one or more of these can be used. The polymerizable monomer having a hydroxyl group (c) is an essential component for the reaction between the resulting acrylic polyol and the polyisocyanate compound which is a crosslinking curing agent, and 2.0 to 35.0% by weight of the polymerizable monomer component, It is preferably used in the range of 3.5 to 23.0% by weight. When it is less than 2.0% by weight, the amount of hydroxyl groups of the obtained acrylic polyol is small, the reactivity with polyisocyanate is lowered, the crosslink density is lowered, and the desired coating performance cannot be obtained. On the other hand, if the amount exceeds 35.0% by weight, the storage stability after blending the polyisocyanate becomes poor.

Examples of the polymerizable ultraviolet absorbing monomer (d) used in the present invention include the following monomers. 2,4-dihydroxybenzophenone or 2,
2-hydroxy-4- (3-methacryloxy-2-hydroxypropoxy) benzophenone obtained by reacting 2 ', 4-trihydroxybenzophenone with glycidyl acrylate or glycidyl methacrylate,
2-hydroxy-4- (3-acryloxy-2-hydroxypropoxy) benzophenone, 2,2'-dihydroxy-4- (3-methacryloxy-2-hydroxypropoxy) benzophenone, 2,2'-hydroxy-4 Examples include-(3-acryloxy-2-hydroxypropoxy) benzophenone and 2 (N-methacryloyl) aminobenzophenone. Polymerizable UV absorbing monomer
(d) is used to further improve the weather resistance of the coating film obtained from the urethane resin coating composition of the present invention, if necessary, in the range of 0 to 10.0% by weight in the polymerizable monomer component. use. If the amount used exceeds 10.0% by weight, the gloss, fleshness and workability deteriorate, and it is preferably used in the range of 0.2 to 5.0% by weight.

The other polymerizable unsaturated monomer (e) used in the present invention is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth).
Acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2
-(Meth) acrylic acid alkyl esters such as ethylhexyl (meth) acrylate, lauryl (meth) acrylate and stearyl (meth) acrylate; epoxy group-containing unsaturated monomers such as glycidyl (meth) acrylate; (meth) acrylamide, N , N'-Dimethylaminoethyl (meth) acrylate, vinylpyridine, vinylimidazole and other nitrogen-containing unsaturated monomers; Vinyl chloride, vinylidene chloride and other halogen-containing unsaturated monomers;
Aromatic unsaturated monomers such as styrene, α-methylstyrene, and vinyltoluene; vinyl esters such as vinyl acetate; vinyl ethers; unsaturated cyanide compounds such as (meth) acrylonitrile, and the like. One or two or more of them may be used.

Polymerizable unsaturated monomers containing an acidic functional group can also be used, for example, carboxyl groups such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid and maleic anhydride. Unsaturated monomers containing; sulfonic acid group-containing unsaturated monomers such as vinyl sulfonic acid, styrene sulfonic acid and sulfoethyl (meth) acrylate; 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyl Examples thereof include acidic phosphoric acid ester unsaturated monomers such as oxypropyl acid phosphate, 2- (meth) acryloyloxy-3-chloro-propyl acid phosphate, and 2-methacryloyloxyethylphenyl phosphoric acid. , One or more selected from these groups can be used .

The other polymerizable unsaturated monomer (e) is used, if necessary, within a range that does not impair the characteristics of the acrylic polyol for urethane resin coatings of the present invention. It can be 0 to 92.9% by weight in the monomer components. Among the other polymerizable monomers (e), the polymerizable monomer containing an acidic functional group acts as an internal catalyst when the acrylic polyol cross-links with the polyisocyanate compound, and the amount thereof is 0-5.0 in polymerizable monomer component
It may be wt%, preferably 0.1-3 wt%.

The acrylic polyol used in the urethane resin coating composition of the present invention is a polymerizable ultraviolet stable monomer (a), a polymerizable unsaturated monomer containing a cycloalkyl group (b), Polymerizable unsaturated monomer containing hydroxyl group
(c), the polymerizable unsaturated monomer containing an acidic functional group-containing polymerizable unsaturated monomer (d) and other polymerizable monomer (e) in the above-mentioned amounts, respectively It can be produced by polymerization by a known polymerization method. Examples of the solvent that can be used when the solution polymerization method is used include, for example, toluene, xylene and other high boiling aromatic solvents; ethyl acetate, ester solvents such as butyl acetate and cellosolve acetate; methyl ethyl ketone, methyl isobutyl ketone. Examples thereof include ketone solvents, and one kind or a mixture of two or more kinds thereof can be used. Also,
Examples of the polymerization initiator include usual radical polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, and di-tert-butyl peroxide. The reaction temperature is from room temperature to 200 ° C, preferably 40 to 1
It is in the range of 40 ° C.

The polyisocyanate compound used in the urethane resin coating composition of the present invention is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, trimethylene diisocyanate, 1,6
Hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and adduct polyisocyanate compounds such as trimethylolpropane adducts, derivatives of these diisocyanates, burettes, isocyanurates, and isocyanate groups of these isocyanate compounds Can be mentioned as a blocked isocyanate compound which is blocked with a compound such as ε-caprolactam, phenol, cresol, oxime, alcohol and the like, and one or a mixture of two or more thereof can be used.

The urethane resin coating composition of the present invention further comprises a known catalyst for promoting the urethanization reaction between the hydroxyl group and the isocyanate group in the acrylic polyol (for example, an organic compound such as di-n-butyltin dilaurylate). A tin compound or a tertiary amine), an organic solvent, a filler, a leveling agent, a plasticizer, a stabilizer, a dye, a pigment, and various additives for coating materials may be appropriately contained.

[0020]

EXAMPLES The present invention will be described below with reference to production examples, examples and comparative examples. In the examples, parts or% means parts by weight or% by weight, respectively, unless otherwise specified. Production Example 1 (Production of Acrylic Polyol) 25 parts of toluene and 25 parts of butyl acetate were charged into a four-necked flask equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas introduction tube, and heated to 100 ° C. While warming, 4-
Methacryloyloxy-2,2,6,6-tetramethylpiperidine 1 part, cyclohexyl methacrylate 20 parts, hydroxyethyl methacrylate 9 parts, methyl methacrylate 10 parts, butyl methacrylate 5 parts, butyl acrylate 4.5 parts, methacrylic acid 0.5 Parts and 2 parts of a polymerizable monomer component consisting of 0.5 parts of azobisisobutyronitrile.
The solution was added dropwise over a period of time and kept at 100 ° C. for 4 hours to obtain an acrylic polyol solution having a nonvolatile content of 50.1% and a viscosity Y (referred to as acrylic polyol solution (1)).

Production Examples 2-7, Comparative Production Examples 1-6 The composition of the polymerizable monomer component used in Production Example 1,
The same procedure as in Production Example 1 was repeated except that the polymerization initiator, the solvent, and the polymerization temperature were as shown in Tables 1 and 2, and the acrylic polyol solutions (2) to (7) and the comparative acrylic polyol solution (1 ) ~ (6) were obtained.

[0022]

[Table 1]

[0023]

[Table 2]

Examples 1 to 3 and Comparative Examples 1 to 4 Acrylic polyol solutions (1) to (3) obtained in Production Examples 1 to 3 and Comparative Production Examples 1 to 4 and comparative acrylic polyol solutions (1) to Titanium oxide (Taipec R-820, manufactured by Ishihara Sangyo Co., Ltd.) was added to each of (4) so that the pigment concentration in the non-volatile content was 40% by weight, and well dispersed by a sand mill. For each of the resulting dispersions (hereinafter referred to as liquid I), a polyfunctional isocyanate (Sumidule N-
75, Sumitomo Bayer Urethane Co., Ltd. was weighed in an amount such that the equivalent ratio of isocyanate groups to the hydroxyl groups in the liquid I was 1: 1 to obtain liquid II. Paint containing the composition for urethane resin coating of the present invention as a vehicle component by mixing the liquid I and liquid II and further diluting with a thinner of toluene: butyl acetate = 1: 1 to a viscosity at which air spray is possible.
(1) to (3) and comparative paints (1) to (4) were obtained.

Then, a zinc phosphate-treated plate was coated with air spray to a dry film thickness of 40 μm, and then 60
Forcibly dried at 30 ° C. for 30 minutes to prepare test pieces for various performance tests. The performance of the coating film was evaluated according to the following four performance test methods except for pencil hardness and weather resistance. The evaluation results are shown in Table 3. <Performance test method> Solvent dilutability; judged by the degree of ease of dilution with thinner. Spray workability; judged by the workability during spraying. Dryability: Judgment immediately after forced drying and judgment by masking test. Feeling of finish; Visual judgment of coating film. Gloss: Comparison of 60-degree specular reflectance measurement values. Adhesion: judged by the adhesion to the coated substrate. Pencil hardness: scratch hardness at Mitsubishi Uni. Solvent resistance: judged by observing the appearance after rubbing with urethane thinner. Weather resistance: Evaluated by the sunshine weatherometer irradiation time until the gloss retention rate reaches 80%.

[0026]

[Table 3]

Examples 4 to 7 and Comparative Examples 5 to 7 Acrylic polyol solutions (4) to (7) obtained in Production Examples 4 to 7 and Comparative Production Examples 3, 5 and 6 and an acrylic polyol solution for comparison (3 ), (5), and (6), a polyfunctional isocyanate (Sumidijur N-75, manufactured by Sumitomo Bayer Urethane Co., Ltd.) is used at an equivalent ratio of isocyanate group to hydroxyl group in the acrylic polyol solution of 1 :. The mixture is mixed in an amount of 1 and further diluted with a thinner of toluene: butyl acetate: ethyl acetate = 1: 1: 1 to a viscosity capable of air spraying, and the urethane resin coating composition of the present invention is used as a vehicle component. Including paints (4) to (7) and comparative paints
(5) to (7) were obtained.

Then, these paints were spray-coated on a white plate which had been precoated with a two-component urethane resin enamel on a zinc phosphate-treated plate, and dried at 80 ° C. for 30 minutes and at room temperature for 1 day to obtain a test piece. A coating performance test was conducted as described above. The film thickness was 30 μm. The evaluation results are shown in Table 4.

[0029]

[Table 4]

[0030]

The urethane resin coating composition of the present invention comprises:
By a coating method such as spray coating, roll coating, and brush coating, it can be applied to metals, plastics, woodworking products, etc. to form a coating film having excellent weather resistance. Furthermore, the urethane resin coating composition of the present invention is excellent in long-term weather resistance, and also has drying property, hardness, gloss, fleshness,
It has a coating film with excellent solvent resistance and excellent workability, and can be used for a wide range of applications such as large structures, automobile repairs, woodworking such as furniture painting, as well as construction and building materials.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08G 18/62 NEN 8620-4J C09D 4/00 PDQ 7921-4J (72) Inventor Shoji Hashiguchi Osaka 5-8 Nishiomitabicho, Suita-shi, Niigata In the Nihon Catalyst Suita Manufacturing Co., Ltd. (72) Inventor Takahiro Aoyama 5-8 Nishimitabicho, Suita-shi, Osaka Niigata Catalyst Suita Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A polymerizable ultraviolet-stable monomer (a) 0.1 to 1
0.0% by weight, a polymerizable unsaturated monomer containing a cycloalkyl group (b) 5.
0 to 97.9% by weight, hydroxyl group-containing polymerizable unsaturated monomer (c) 2.0 to 35.0% by weight, polymerizable UV absorbing monomer (d) 0 to 10.0% by weight, and other copolymerizable polymerizable monomers Saturated monomer (e) 0-92.9% by weight of a polymerizable monomer component (however, the total of (a), (b), (c), (d), and (e) is 100% by weight. And a polyisocyanate compound. 2. The composition for urethane resin coating according to claim 1, wherein the polymerizable ultraviolet absorbing monomer (d) is 0.1 to 5.0% by weight in the polymerizable monomer component. 3. The polymerizable ultraviolet-stable monomer (a),
The following general formula (I) and / or general formula (II): [Chemical 2] (However, in the general formulas (I) and (II), R ₁ is a hydrogen atom or a cyano group, R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R ₄ is The composition for a urethane resin coating according to claim 1, wherein a compound represented by a hydrogen atom or an alkyl group having 1 to 18 carbon atoms and X represents an imino group or an oxygen atom is used.