JP2001329212A - Cold-setting coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cold-setting coating composition capable of forming an elastic film excellent in weatherability and water resistance by using an oxidation curing urethane-modified vinyl resin. SOLUTION: The coating composition contains as the film-forming constituent a urethane-modified vinyl resin obtained by reacting an epoxidized vinyl copolymer (a) comprising a copolymer of an epoxidized polymerizable unsaturated monomer and other polymerizable unsaturated monomer copolymerizable therewith with a fatty acid component (b) containing an unsaturated fatty acid, and then reacting the reaction product with a compound (c) having an isocyanato group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room-temperature-curable coating composition which can form an elastic coating film excellent in weather resistance and water resistance using an oxidation-curable urethane-modified vinyl resin.

[0002]

2. Description of the Related Art Conventionally, alkyd resins using unsaturated fatty acids are well known as paint resins which have room temperature curability and are stable for a long time in a solution state. However, this alkyd resin is susceptible to deterioration in weather resistance due to ultraviolet rays, and is insufficient in performance for use in outdoor applications. As a method of solving this problem of weather resistance, for example, British Patent No. 79
Japanese Patent No. 3,776 proposes an acrylic resin modified with a fatty acid. However, the fatty acid-modified acrylic resin, although slightly improved in weather resistance, contains a low-polarity soft component fatty acid, so that the coating performance such as weather resistance, water resistance, and acid / alkali resistance is still low. It was not enough.

[0003]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, by using a resin obtained by further modifying a fatty acid-modified acrylic resin with a compound having an isocyanate group, The inventors have found that the weather resistance and water resistance of the coating film are improved, and that the lower coating film is excellent in crack followability, and have completed the present invention.

That is, the present invention relates to an epoxy group-containing vinyl copolymer (a) which is a copolymer of an epoxy group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable with the monomer. A reaction product with a fatty acid component (b) containing an unsaturated fatty acid and a urethane-modified vinyl resin obtained by further reacting a compound (c) having an isocyanate group as a film-forming component; A curable coating composition is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a urethane-modified vinyl resin comprises an epoxy group-containing vinyl copolymer (a),
An oxidation-curable resin obtained by reacting a compound (c) having an isocyanate group with a reaction product of a fatty acid component (b) containing an unsaturated fatty acid.

The above epoxy group-containing vinyl copolymer (a)
Examples of the epoxy group-containing polymerizable unsaturated monomer which is a copolymer component of glycidyl (meth) acrylate,
Β-Methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) acrylate, allyl glycidyl ether, and the like.

Other polymerizable unsaturated monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and t- (meth) acrylate. -Butyl, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate,
C1-C24 alkyl or cycloalkyl esters of acrylic acid or methacrylic acid such as stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2 -Hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-
Α, such as hydroxybutyl (meth) acrylate,
α, β-ethylenically unsaturated carboxylic acid esters having an alkylene oxide chain and a hydroxyl group such as hydroxyalkyl esters of β-ethylenically unsaturated carboxylic acid, and polyethylene glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate Hydroxyl-containing monomers such as; (meth) acrylic acid 1,2,2,
6,6-pentamethylpiperidyl, 2,2,6,6-tetramethylpiperidinyl (meth) acrylate, 2-
(2'-hydroxy-5'-methacryloxyphenyl) -2H-benzotriazole, styrene, vinylbenzene, vinyl acetate and the like.

[0008] In the epoxy group-containing vinyl copolymer (a), the copolymerization ratio of the epoxy group-containing polymerizable unsaturated monomer to the other polymerizable unsaturated monomer is usually in the range of the epoxy group-containing polymerizable unsaturated monomer. Is 3-70% by weight,
The content of the unsaturated fatty acid (b) is preferably in the range of 10 to 50% by weight, and the other polymerizable unsaturated monomer is in the range of 30 to 97% by weight, preferably 50 to 90% by weight. It is suitable from the viewpoints of addition reactivity at the time of the reaction and solubility of the obtained epoxy group-containing vinyl copolymer (a) in a solvent.

The epoxy group-containing vinyl copolymer (a)
In the determination of the amount of the hydroxyl group-containing monomer used, in the reaction with the polyisocyanate compound (c),
The amount should be determined so that gelling does not occur. Usually, it is appropriate that the amount of the hydroxyl group-containing monomer to be used is 30% by weight or less in the monomer component constituting the vinyl copolymer (a).

The above-mentioned epoxy group-containing vinyl copolymer (a)
The copolymerization method for obtaining the compound is not particularly limited, but from the viewpoint of easy reaction with the fatty acid component (b) and the compound having an isocyanate group (c), the radical polymerization in an organic solvent is carried out. A solution polymerization method performed in the presence of a polymerization initiator is preferred.

The above epoxy group-containing vinyl copolymer (a)
Examples of the radical polymerization initiator used in the synthesis by solution polymerization of azo-based polymerization include azo-based polymerization such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile). Initiators: peroxide-based polymerization initiators such as lauryl peroxide, t-butylperoxy-2-ethylhexanoate, and benzoyl peroxide. Further, as the organic solvent used in the synthesis by solution polymerization, for example, n-hexane,
Aliphatic hydrocarbon solvents such as n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane and methylcyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, xylene and ethylbenzene; mineral spirits , "Swazol 1000" (product of Cosmo Oil), petroleum solvents such as petroleum ether, petroleum benzene, petroleum naphtha; ketone solvents such as methyl isobutyl ketone; ester solvents such as isobutyl acetate; alcohol solvents such as isopropanol; Can be used alone or as a mixture of two or more, if necessary.

The above epoxy group-containing vinyl copolymer (a)
Has a number average molecular weight of 1,000 to 100,000, particularly 2,000 to 70,000, and a glass transition temperature (Tg) of 0 to 100 ° C.
It is suitable from the viewpoint of the physical properties and the quick drying property of the obtained coating film.

The above-mentioned fatty acid component (b) is a fatty acid component containing an unsaturated fatty acid essentially and, if necessary, a saturated fatty acid, and preferably has an iodine value in the range of about 50 to 200. is there. When the iodine value is less than about 50, the curability of the coating film is reduced. On the other hand, when the iodine value exceeds about 200, gelation may occur during resin production, which is not preferable.

Representative examples of unsaturated fatty acids which are essential components of the fatty acid component (b) include fish oil fatty acids, dehydrated castor oil fatty acids, safflower oil fatty acids, linseed oil fatty acids, soybean oil fatty acids, sesame oil fatty acids, poppy oil fatty acids, Eno oil fatty acids, hemp oil fatty acids, grape kernel oil fatty acids, corn oil fatty acids, tall oil fatty acids, sunflower oil fatty acids, cottonseed oil fatty acids, walnut oil fatty acids, rubber seed oil fatty acids, and the like.
The unsaturated fatty acid is an oxidatively curable fatty acid having a polymerizable unsaturated group, and imparts oxidative curability to the urethane-modified vinyl resin in the present invention.

The saturated fatty acid which the fatty acid component (b) can further contain, if necessary, in addition to the unsaturated fatty acid, may be, for example, coconut oil fatty acid, hydrogenated coconut oil fatty acid, palm oil fatty acid and the like. Drying oil fatty acids; caproic acid,
Examples thereof include capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid.

The proportion of the fatty acid component (b) is in the range of 1 to 60 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the resin solid content of the epoxy group-containing vinyl copolymer (a). Is preferable in terms of the curability and weather resistance of the obtained coating film.

In the present invention, the reaction between the epoxy group-containing vinyl copolymer (a) and the fatty acid component (b) is carried out by reacting the epoxy group in the copolymer (a) with the carboxyl group in the fatty acid component (b). This is generally based on the esterification reaction of this compound, and this reaction usually produces a secondary hydroxyl group. In this reaction, if necessary, a reaction catalyst such as a tertiary amine such as N, N-dimethylaminoethanol; and a quaternary ammonium salt such as tetrabutylammonium bromide can be used. When using a reaction catalyst, the amount used is
An appropriate amount is in the range of 0.01 to 100 parts by weight based on 100 parts by weight of the total of the copolymer (a) and the fatty acid component (b).

The reaction conditions between the copolymer (a) and the fatty acid component (b) are such that the epoxy group and the fatty acid component (b) in the copolymer (a) can be reacted without causing a problem such as gelation.
Any condition can be used as long as it can react with the carboxyl group in it,
Generally, heating at about 100 to 170 ° C. for about 2 to 10 hours is suitable.

Compound (c) having isocyanate reacted with the fatty acid-modified copolymer obtained as described above
Are, for example, tolylene diisocyanate, xylylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, bis (isocyanate methyl) cyclohexane, tetramethylene diisocyanate
, Hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylene diisocyanate
, Isophorone diisocyanate and other aromatic, alicyclic or aliphatic polyisocyanate compounds, isocyanurate and buret forms of these polyisocyanate compounds, and excess amounts of these polyisocyanate compounds Terminal isocyanate-containing compound, lysine triisocyanate obtained by reacting a low molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, trimethylolpropane, hexanetriol, castor oil, etc.
And the like.

The amount of the compound (c) having an isocyanate group used is such that the equivalent ratio (NCO / OH) of the isocyanate group in the compound (c) having an isocyanate group to the hydroxyl group in the fatty acid-modified copolymer is 0. 05-
It is preferable to determine the value so as to be in the range of 2.0, preferably in the range of 0.1 to 1.2 from the viewpoint of the weather resistance and physical properties of the formed coating film.

When the compound (c) having an isocyanate group is reacted with the fatty acid-modified copolymer by the reaction of the above (a) and (b), depending on the progress of the reaction,
For example, if the viscosity of the reaction system increases and exceeds the appropriate range, the reaction can be controlled by adding an appropriate amount of alcohols, phenols, lactams, oximes and the like.

The reaction between the fatty acid-modified copolymer and the compound (c) having an isocyanate group can be carried out, if necessary, in the presence of a reaction catalyst. The above reaction is based on the reaction between the hydroxyl group in the fatty acid-modified copolymer and the isocyanate group in the compound (c) having an isocyanate group. The hydroxyl group in the fatty acid-modified copolymer includes a hydroxyl group originally present in the copolymer (a) and a hydroxyl group generated by a reaction between the copolymer (a) and the fatty acid component (b).

Examples of the reaction catalyst include dibutyltin bis (acetylacetonate), dibutyltin diacetate, dibutyltin di (2-ethylhexylate), dibenzyltin di (2-ethylhexylate), and dibutyltin dilaurate. And organic metal compounds such as dibutyltin diisooctyl maleate and tetrabutyl titanate. These reaction catalysts can be used alone or in combination of two or more.

The reaction catalyst is used in an amount of 0.001 to 5 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the total of the fatty acid-modified copolymer and the compound (c) having an isocyanate group.
The use of 005 to 1 part by weight is appropriate from the viewpoint of the effect of accelerating the reaction. The coating composition of the present invention comprises the urethane-modified vinyl resin as a film-forming component, and further, if necessary, an oxidation curing reaction catalyst, pigments, an organic solvent,
Contains paint additives such as UV absorbers, light stabilizers, surface conditioners, pigment dispersants, rheology control agents, anti-skinning agents for coating liquids, fungicides, anti-algal agents, plasticizers, defoamers, etc. be able to.

Examples of the oxidative curing catalyst include organometallic compounds such as cobalt octylate, cobalt naphthenate, manganese octylate, manganese naphthenate, zirconium octylate, zirconium naphthenate, and lead octylate.

Further, as the rheology control agent,
Examples thereof include thickeners such as polyethylene oxide and fatty acid amide wax, alkoxysilyl compounds and condensates thereof, and non-aqueous dispersion type resins. These can be used alone or in combination.

The coating film obtained by using the composition of the present invention has very good appearance such as surface gloss, excellent weather resistance, chemical resistance, and alkali resistance. Can be cured in just a few hours after painting, and exhibits excellent room temperature curability.

The coating composition of the present invention comprises metal, slate,
It can be applied to the surface of materials such as mortar, the undercoating of these (sealing material, base adjustment agent, thickening material, etc.) or the surface of old paint film, etc., especially for inorganic building materials such as slate and mortar, and It is useful on the surface of a coated film having elasticity coated on the surface.

[0029]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. “Parts” and “%” mean “parts by weight” and “% by weight”, respectively.

Production Example 1 of Urethane-Modified Vinyl Resin Solution Preparation Example 1 100 parts of mineral spirits were charged into a flask, and the temperature was raised while stirring to 115 ° C. while passing nitrogen gas through. Next, a mixture of the following monomers and the like was added dropwise over 4 hours while maintaining the temperature at 115 ° C.

Styrene 20 parts n-butyl methacrylate 25 parts i-butyl methacrylate 10 parts 2-ethylhexyl acrylate 25 parts glycidyl methacrylate 20 parts 2,2′-azobisisobutyronitrile 1 part Then 2 at 115 ° C. After aging for 30 hours, the temperature was raised to 140 ° C., and 30 parts of linseed oil fatty acid and N, N
160 parts of dimethylaminoethanol
For 5 hours to carry out an addition reaction of the fatty acid. The resin acid value was traced by a KOH titration method, and the time when the resin acid value became 1.0 or less was defined as the end point. After completion of the reaction, 45 parts of xylene was added and diluted to obtain a brown transparent viscous fatty acid-modified copolymer solution (A-1) having a nonvolatile content of 50%.

The fatty acid-modified copolymer solution (A-1) was
After cooling to 00 ° C., 5 parts of “Desmodur H” (manufactured by Sumitomo Bayer Urethane, hexamethylene diisocyanate), 14 parts of mineral spirit, 6 parts of xylene, and 0.05 part of dibutyltin dilaurate as a reaction catalyst
And react for 2 hours at the same temperature to obtain about 45% non-volatile content.
A brown transparent viscous urethane-modified vinyl resin solution was obtained.

Production Example 2 12 parts of “TPA-100” (produced by Asahi Kasei Corporation, isocyanurate of hexamethylene diisocyanate) was added to 275 parts of the 50% fatty acid-modified copolymer solution (A-1) obtained in Production Example 1, 30 parts of xylene and 0.05 parts of dibutyltin dilaurate as a reaction catalyst were added, and the temperature was adjusted to 100.
The reaction was carried out for 1 hour while the temperature was maintained at ° C. Next, 2 parts of n-butyl alcohol was added and the mixture was further reacted for 1 hour to obtain a brown transparent viscous urethane-modified vinyl resin solution having a nonvolatile content of about 45%.

Production Example 3 To 275 parts of the 50% fatty acid-modified copolymer solution (A-1) obtained in Production Example 1, "TSE-100" (available from Asahi Kasei Corporation, isocyanurate of hexamethylene diisocyanate) was softened. Modified) 23 parts, mineral spirit 30 parts, xylene 15 parts and dibutyltin dilaurate 0.05 part as a reaction catalyst were added, and the temperature was 100 ° C.
For 1 hour. Next, 2 parts of n-butyl alcohol was added and the mixture was further reacted for 1 hour to obtain a brown transparent viscous urethane-modified vinyl resin solution having a nonvolatile content of about 45%.

Production Example 4 100 parts of mineral spirits were charged into a flask, and the temperature was raised while stirring to 115 ° C. while passing nitrogen gas. Next, a mixture of the following monomers and the like was added dropwise over 4 hours while maintaining the temperature at 115 ° C.

Styrene 15 parts n-butyl methacrylate 25 parts i-butyl methacrylate 10 parts 2-ethylhexyl acrylate 25 parts glycidyl methacrylate 20 parts “RUVA-093” (Note 1) 5 parts 2,2′-azobis Isobutyronitrile 1 part After aging at 115 ° C for 2 hours, the temperature was raised to 140 ° C, and then linseed oil fatty acid 30 parts and N, N
160 parts of dimethylaminoethanol
For 5 hours to carry out an addition reaction of the fatty acid. The resin acid value was traced by a KOH titration method, and the time when the resin acid value became 1.0 or less was defined as the end point. After completion of the reaction, 45 parts of xylene was added and diluted to obtain a brown transparent and viscous fatty acid-modified copolymer solution (A-2) having a nonvolatile content of 50%.

The fatty acid-modified copolymer solution (A-2) was mixed with 1
After cooling to 00 ° C., 5 parts of “Desmodur H” (manufactured by Sumitomo Bayer Urethane, hexamethylene diisocyanate), 14 parts of mineral spirit, 6 parts of xylene, and 0.05 part of dibutyltin dilaurate as a reaction catalyst
And react for 2 hours at the same temperature to obtain about 45% non-volatile content.
A brown transparent viscous urethane-modified vinyl resin solution was obtained. (Note 1) “RUVA-093”: Otsuka Kagaku Co., Ltd. 2-
Preparation of (2'-hydroxy-5'-methacryloxyphenyl) -2H-benzotriazole coating composition Examples 1-4 and Comparative Example 1 Each of the 45% urethane-modified vinyl resin solutions obtained in the above Production Examples was Using, the composition shown in Table 1 (solid content indication)
Then, each component was added to a 1 liter mayonnaise bottle together with 250 parts of glass beads having a diameter of 2 mm, and stirred for 2 hours with a paint shaker to form a pigment paste, which was then mixed with the above 45% urethane-modified vinyl resin solution. And as a curing catalyst cobalt naphthenate, lead naphthenate is added as shown in the same table, and stirred until uniform,
The glass bead was removed to obtain each room temperature curable coating composition. In Comparative Example 1, a fatty acid-modified copolymer solution (A-1) was used instead of the urethane-modified vinyl resin solution.

Performance Tests Each of the room temperature curable coating compositions obtained in the above Examples and Comparative Examples was subjected to various tests based on the following test methods. The test results are shown in Table 1 below.

Test method (* 1) Initial drying property: Each cold-curable coating composition was applied on a glass plate with a 300 μm applicator, and then applied at 20 ° C.
After being left at 70% RH for 6 hours, the coating film was examined for dryness to the touch and evaluated according to the following criteria.

◎: No fingerprints are formed at all. ○: Slight fingerprints are formed. Δ: Fingerprints are formed. X: Coating film adheres to fingers. (* 2) Gloss of coating film: Each room temperature curable coating composition on a glass plate. After coating with a 300 μm applicator,
After drying in a 0% RH room for one week, the 60 ° specular reflectance was measured and evaluated according to the following criteria.

◎: 90% or more ○: 80% or more, less than 90% Δ: 70% or more, less than 80% ×: less than 70% (* 3) Weather resistance: “Allethretan” (manufactured by Kansai Paint Co., Ltd., white gloss) Each of the room-temperature curable coating compositions is applied with a 300 μm applicator on a slate plate coated with an existing coating) and dried for 1 week in a room at 20 ° C. and 70% RH.
It was evaluated by the gloss retention when exposed for 1500 hours with a sunshine weatherometer.

◎: 90% or more ：: 80% or more, less than 90% Δ: 70% or more, less than 80% ×: less than 70% (* 4) Water resistance: Each cold-curable coating composition on a slate plate The product is coated with a 300 μm applicator and
% RH in a room for one week, and the coated plate was washed with tap water (2%).
(0 ° C.) for 3 days, the state of the coating film was observed and evaluated according to the following criteria.

：: No abnormality Δ: Slight swelling observed X: Severe swelling observed (* 5) Acid resistance: The coated plate obtained in the same manner as (* 1)
0.5 cc of a 0.1N aqueous sulfuric acid solution was added dropwise at 20 ° C.
After standing for 4 hours, the film was washed with water and the state of the coating film was observed.

：: No abnormality Δ: Slight whitening observed X: Remarkable whitening and surface etching observed (* 6) Hot / cold repetition test: "Ales rubber tile sealer" (manufactured by Kansai Paint Co., Ltd., sealer) applied 150g
/ M ^2, and then apply “Ales Rubber Tile Rough” (manufactured by Kansai Paint Co., Ltd., a base material for thickening the exterior) with a 2 mm blade. Then, each cold-curable coating composition is applied on the coated plate with a brush so as to have a coating amount of 120 g / m ^2, and after leaving for 4 hours, the same cold-curing coating composition is further applied at a coating amount of 120 g / m ² . A test coated plate was prepared by re-coating with a brush as described above. This test coated plate was subjected to JIS A-690.
According to the hot / cold repetition test of No. 9, <immersion in water for 18 hours
Cooling in a −20 ° C. incubator for 3 hours to heating in a 50 ° C. incubator for 5 hours> was regarded as one cycle, and the state of the coating film surface after the 15-cycle test was visually observed.

◎: No abnormality ○: Slight swelling is observed △: Cracks and swelling are partially observed ×: Marked swelling and swelling are observed throughout

[0046]

The coating composition of the present invention improves the weather resistance and water resistance of the coating film obtained by using an oxidation-curable urethane-modified vinyl resin as a film-forming component, and further improves the cracking of the lower coating film. It has the ability to follow. Therefore, the coating composition of the present invention is very useful for architectural exterior use, especially for inorganic building materials.

[0047]

[Table 1]

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroyuki Tsukadaira 3-12-1, Minamirokugo, Ota-ku, Tokyo Kansai Paint Co., Ltd. F term (reference) 4J038 CG141 CH171 CH191 CJ031 CJ051 CJ101 CJ131 DG191 DG261 GA07 GA11 LA02 NA03 NA04 NA11 PA18 PB05 PC02 PC04

Claims (2)

[Claims] 1. An epoxy group-containing vinyl copolymer (a) which is a copolymer of an epoxy group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable with the monomer.
And a reaction product of a fatty acid component (b) containing an unsaturated fatty acid and a urethane-modified vinyl resin obtained by reacting a compound (c) having an isocyanate group as a film-forming component. Room temperature curable coating composition. 2. An epoxy group-containing vinyl copolymer (a) comprising:
The room temperature curable coating composition according to claim 1, wherein the polymerizable unsaturated monomer having an epoxy group is copolymerized at a ratio of 3 to 70% by weight and another polymerizable unsaturated monomer at a ratio of 30 to 97% by weight.