JPH0368073B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for coatings that is curable at room temperature or low temperature and is composed of a silyl group-containing vinyl copolymer that has excellent adhesion, storage stability, and weather resistance, and an isocyanate compound. In recent years, vinyl resins containing hydrolyzable silyl groups at the terminal or side chain have been developed in order to improve adhesion to inorganic substances and weather resistance (for example, Japanese Patent Application Laid-open No. 55-129405, Japanese Patent Application Laid-open No. 129405, No. 57) −172917,
(Japanese Patent Publication No. 60-47076, etc.) However, these do not contain an acid as a copolymerization component, or even if they contain an acid, they gel or thicken to the point of gelatinization when the resin is synthesized using an acid other than maleic anhydride. Moreover, since γ-methacryloxypropyltrimethoxysilane is used as the silane compound, storage stability is poor, and alcohol is added as a solvent component.
A hydrolysable ester compound must be added. Furthermore, it has the disadvantage of poor interlayer adhesion when coated over and over again. As a result of intensive research on silyl group-containing vinyl resins as resins with excellent weather resistance, the present inventors discovered a resin composition that does not have the various drawbacks mentioned above and has good storage stability, topcoatability, and weather resistance. Ta. Furthermore, by curing with an isocyanate compound, it has excellent adhesion to inorganic and organic substances.
In particular, the inventors have found that secondary adhesion is improved, leading to the present invention. That is, the present invention provides the formula

[Formula] (wherein, R is a monovalent hydrocarbon group selected from alkyl groups, aryl groups, and aralkyl groups having 1 to 10 carbon atoms, X is a hydrolyzable group, and n is an integer of 1, 2, or 3. 5 to 20% by weight of a silane compound shown in
Hydrolyzable silyl group-containing vinyl copolymer 100 obtained by copolymerizing 5 to 20% by weight of a hydroxyl group-containing vinyl monomer and 55 to 89.5% by weight of other copolymerizable vinyl monomers. The present invention relates to a coating resin composition that is curable at room temperature or low temperature and has excellent adhesion, storage stability, and weather resistance, and is comprised of 1 part by weight and 0.1 to 50 parts by weight of an isocyanate compound. Representative examples of the silane compound as component (A) used in the present invention include vinyltrimethoxysilane, vinyltriethoxysilane, vinylpropoxysilane,
Examples include vinyltris(β-methoxyethoxy)silane. Among these, vinyltriethoxysilane is particularly preferred. The hydrolyzable silane compound is preferably used in an amount ranging from 5 to 20% by weight in the vinyl copolymer from the viewpoints of adhesion to inorganic materials, weather resistance, and cost. If it is less than 5% by weight, the adhesion to inorganic substances and weather resistance will not be improved, and if it is more than 20% by weight, the price will be high and the polymerization reaction rate will be poor. Component (B), acrylic acid and/or methacrylic acid, is necessary to improve the pigment dispersibility of the copolymer and the adhesion to organic substances, and is used in the range of 0.5 to 5% by weight in the vinyl copolymer. It is preferable to do so. These acid components also function as internal catalysts when the hydrolyzable silyl groups are crosslinked by moisture in the atmosphere at room or low temperatures. Hydroxyl group-containing vinyl monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, addition polymer of 2-hydroxyethyl (meth)acrylate and ε-caprolactone, Aronix 5700 [Toagosei Kagaku Products manufactured by Kogyo Co., Ltd.] can be used. The amount used is 5 to react with the isocyanate compound.
A range of ~20% by weight is desirable. Furthermore, by copolymerizing with a vinyl monomer copolymerizable with the silane compounds and polar group-containing vinyl monomers mentioned above, it is possible to obtain an isocyanate compound containing a hydrolyzable silyl group. A reacting vinyl copolymer is obtained. Typical examples of such copolymerizable vinyl monomers include methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate.
(meth)acrylic acid esters such as acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate; aromatic vinyl compounds such as styrene and vinyltoluene; and vinyl acetate, vinyl versatate, Examples include vinyl propionate. The most preferred method for preparing the vinyl copolymer described above is solution radical polymerization. Typical solvents used in this case include hydrocarbons such as toluene, xylene, cyclohexane, and n-hexane; esters such as ethyl acetate, butyl acetate, or isobutyl acetate; or acetone, methyl ethyl ketone, methyl isobutyl ketone, There are ketone solvents such as cyclohexanone. Polymerization can be carried out by a conventional method using such a solvent and a polymerization initiator such as an azo type or a peroxide type, and a chain transfer agent such as lauryl mercaptan or n-dodecyl mercaptan can also be used during the polymerization. . The isocyanate compounds used in the present invention are preferably aliphatic polyisocyanates and alicyclic polyisocyanates from the viewpoint of weather resistance, and bifunctional diisocyanates such as hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate; trimethylol Addition compounds of polyhydric alcohols such as propane and bifunctional diisocyanates; water-denatured hexamethylene diisocyanates, etc. can be used; commercially available such compounds include "Burnock".
[Dainippon Ink and Chemicals Co., Ltd. product] "Dulanate"
[Asahi Kasei Industries, Ltd. products] etc. The amount of the isocyanate compound used in the present invention is not particularly limited, but the amount is 0.1 to 50 parts by weight per 100 parts by weight of the vinyl copolymer, and the number of hydroxyl groups in the copolymer component and the number of isocyanate groups in the isocyanate compound are The ratio is 1/
It is appropriate to use it in a range of 0.1 to 1/1.2, and weather resistance and adhesion can be ensured at such a blending ratio. Furthermore, during curing, a curing accelerator may or may not be used. When used, dibutyltin dilaurate, lead octylate, triethylenediamine, etc. are effective, and the amount added is usually 0.001 to 0.2% by weight based on the solid content of the resin. The composition of the present invention can be used as a clear paint or a colored paint. Typical examples of pigments that can be used as such colored paints include extender pigments such as calcium carbonate, kaolin, and talc; inorganic pigments such as titanium oxide, iron oxide, yellow lead, cadmium oxide, and carbon black. Pigments; or various organic pigments such as permanent red, phthalocyanine blue, phthalocyanine green, and quinacridone pigments. Furthermore, if necessary, dispersion stabilizers, leveling agents, color separation inhibitors, cellulose derivatives such as cererose acetate butyrate, etc. commonly used in paints can be added. The paint obtained using the resin composition of the present invention is
A cured coating film with excellent adhesion and weather resistance is obtained by applying the coating to various objects using conventional methods and drying it at room temperature for several days. A cured coating can also be obtained by baking for 30 minutes. Furthermore, it has good adhesion even when coated over and over again, providing workability similar to that of conventional acrylic/urethane paints. The composition of the present invention thus obtained can be used as a paint, primer, etc. for inorganic surfaces such as iron plates, galvanized iron plates, aluminum plates, roof tiles, slate plates, etc., and inorganic surfaces such as plastics and wood. Next, the present invention will be specifically explained with reference to Examples and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified. Reference Example 1 (Preparation example of vinyl copolymer containing silyl group) Into a reactor equipped with a stirring device, a thermometer, and a reflux condenser, 80 parts of toluene, 130 parts of isobutyl acetate,
and 2.5 parts of methacrylic acid (MAA).90
℃, and 200 parts of methyl methacrylate (MMA) and n-butyl acrylate (n-
BA) 80 parts, 2-hydroxyethyl methacrylate (HEMA) 30 parts, vinyltriethoxysilane (VTES) 35 parts, azobisisobutyronitrile (AIBN) 2.6 parts, 1,1-ditertiarybutylperoxy-trimethyl - A mixture of 2.6 parts of cyclohexane [Sanperox CY1.1, Sanken Kako Co., Ltd. product] and 40 parts of toluene was added dropwise over 1.5 hours, kept at the same temperature for 2 hours, and then
95-105 with 3.0 parts of AIBN and 50 parts of toluene
The mixture was kept at ℃ for 3 hours and diluted with 50 parts of toluene to obtain a vinyl copolymer solution. The nonvolatile content (hereinafter abbreviated as NV) of this copolymer solution was 46.8%,
The viscosity (25°C) was 6680 cps. Hereinafter, this will be abbreviated as copolymer (A-1). Reference Example 2 (Example of Preparation of Vinyl Copolymer Containing a Silyl Group) 70 parts of toluene, 120 parts of isobutyl acetate, and 2.0 parts of MAA were charged into the same reactor as in Reference Example 1, and
MMA165 parts, n-BA80 parts, HEMA30 parts,
35 parts of VTES, 35 parts of cyclohexyl methacrylate
part, AIBN2.4 part, Sanperox CY1・1 2.8
and 60 parts of toluene are added dropwise,
Add 3.0 parts of AIBN and 35 parts of toluene, react in the same way, dilute with 65 parts of toluene, and the NV is 47.3%.
A copolymer with a viscosity of 4050 cps was obtained. Hereinafter, this will be referred to as copolymer (A-2). Reference Example 3 (Preparation example of vinyl copolymer containing silyl groups) 90 parts of toluene and 100 parts of butyl acetate were charged into the same reactor as in Reference Example 1, and 2.5 parts of MAA,
MMA100 parts, n-BA60 parts, HEMA15 parts, 2-
15 parts of hydroxyfuropyl methacrylate, 120 parts of n-butyl methacrylate, 35 parts of VTES,
A mixture consisting of 2.6 parts of AIBN, 2.6 parts of Sanperox CY1・1 and 60 parts of toluene was added dropwise,
Add 3.0 parts of AIBN and 30 parts of toluene, react in the same way, dilute with 70 parts of toluene, and the NV is 47.5%.
A copolymer solution with a viscosity of 1150 cps was obtained. below,
This is referred to as copolymer (A-3). Reference Example 4 The raw material mixture of Reference Example 2 except for methacrylic acid reacted in the same manner as Reference Example 2, and the NV was 46.7% and the viscosity was
A copolymer of 2400 cps was obtained. This was made into a copolymer (B
−1). Comparative Example 1 A reaction was carried out in the same manner as in Reference Example 1, using 35 parts of γ-methacryloxypropyltrimethoxysilane in place of 35 parts of VTES in Reference Example 1, and gelation occurred 1 hour and 10 minutes after the completion of dropping. Examples 1 to 3 Copolymers (A-1) and (A-
2) and (A-3) using 470 parts each,
A white paint base composition was prepared by mixing 30 parts of toluene, 40 parts of isobutyl acetate, and 72 parts of "Taipiure-R-960" (rutin-type titanium oxide manufactured by DuPont). 100 parts of each paint base composition contains
24A−90CX” [isocyanate compound manufactured by Asahi Kasei Industries, Ltd.] was added, and toluene/xylene =
It was diluted to a spray viscosity using a mixed solvent of 60/40 (weight ratio), applied to various test plates, dried for one week at 20℃, and then tested for adhesion, secondary physical properties, and accelerated weathering resistance. The results are shown in Table 1. When the white paints of Examples 1 to 3 were stored in a closed container at 50°C for one month, none of them gelled and had good storage stability. Comparative Example 2 Table 1 shows the results of a similar performance test using a commercially available acrylic/urethane resin paint for slate roof tiles manufactured by Mizutani Paint Co., Ltd.

[Table] The white paints of Examples 1 to 3 were applied to a colored galvanized iron board, dried at 20°C for 24 hours, then overcoated with acrylic resin paint or acrylic/urethane resin paint, and the adhesion after drying for 3 days. The properties are shown in Table 2. Comparative Example 3 A commercially available silyl group-containing vinyl copolymer was applied to a colored galvanized iron plate, and after drying at 20°C for 24 hours,
Table 2 shows the adhesion after applying an acrylic resin paint or an acrylic urethane resin paint and drying it for 3 days.

[Table] Examples 4 to 5/Comparative Example 4 Copolymers (A-2) and (A-
3) and (B-1), using 96 parts by weight each, 48 parts by weight of butyl acetate, 40 parts by weight of Special Black (manufactured by Degussa), and 180 parts by weight of glass beads.
A paint paste was produced by mixing parts by weight and dispersing for a predetermined time using a high-speed disperser. The state of dispersion was observed using a particle size analyzer, and evaluated as ○ when uniformly and finely dispersed and × when not dispersed. The results are shown in Table 3.

[Table] 400 parts by weight of each copolymer and 120 parts by weight of toluene were added to the above black paint paste, and the main liquid of each black paint was left at room temperature for one day, and the state of varnish floating was observed. . The paints obtained in Examples 4 and 5 were in a uniformly dispersed state, but in the paint obtained in Comparative Example 4, the pigments aggregated and precipitated, and the resin layer floated on top and was separated. From these results, it is known that the resin composition of the present invention provides a coating film with excellent adhesion, pigment dispersibility, storage stability, and weather resistance.

Claims (1)

[Claims] 1 (A) Formula [Formula] (In the formula, R is a monovalent hydrocarbon group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group, and an aralkyl group, and X is a hydrolyzable group. , n is an integer of 1, 2, 3) 5 to 20% by weight (B) Acrylic acid and/or methacrylic acid
0.5-5% by weight (C) Vinyl monomer containing hydroxyl group 5-20% by weight (D) Other copolymerizable vinyl monomers
A resin composition for coatings comprising 100 parts by weight of a vinyl copolymer containing a hydrolyzable silyl group obtained by copolymerizing 55 to 89.5% by weight and 0.1 to 50 parts by weight of an isocyanate compound.