JPS6115104B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition for antirust paint. More specifically, the present invention relates to a resin composition for rust-preventing paint using an acrylic copolymer containing a silicone-containing monomer. Conventionally, oil-based resins, epoxy resins, and the like have been known as resins with excellent rust prevention properties. However, although acrylic resins have excellent physical properties, no one with sufficient rust prevention performance has been obtained. In addition, many reports have already been made regarding silicone resins, but all of them have the drawback of poor rust prevention ability. The present invention is aimed at improving the above-mentioned defects of acrylic resins and silicone resins, and uses a combination of a silicone-containing monomer copolymer and an acrylic copolymer as a resin composition for rust-preventing paint. It is related to. That is, the present invention provides (a) at least one silicone-containing monomer represented by the following general formula: 0.1 to 50
% by weight, preferably 2-30% by weight, (In the above formula, R ₁ is a hydrogen atom or a methyl group,
R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 4 carbon atoms, and n is an integer of 1 to 12. ) 5-50 parts by weight, preferably 10-30 parts by weight of an acrylic copolymer consisting of 5-50% by weight of styrene, preferably 15-40% by weight and 94.9% by weight or less, preferably 83-30% by weight of methanoacrylic acid ester (b) 50 to 95 parts by weight, preferably 70 to 90 parts by weight, of an acrylic copolymer containing 5 to 50 parts by weight of styrene. The silicone-containing monomer used in the present invention is a (meth)acryloalkyltrialkoxysilane or a derivative thereof. Specific examples include methacrylomethyltrimethoxysilane, acryloethylmethoxyethoxybutoxysilane, methacrylopropyltrimethoxysilane,
These include acrybutylmethoxydibutoxysilane, methacrylohexyltriethoxysilane, acrylooctylbutoxydimethoxysilane, methacrylolaurylpropoxydimethoxysilane, and the like. The above-mentioned silicone-containing monomer is generally obtained by dehalogenating a halogenated alkyltrialkoxysilane and an acrylate or a methacrylate. In addition to silicone-containing monomers and styrene, vinyl monomers to be copolymerized include vinyl toluene, (meth)acrylic acid, (meth)acrylic acid esters [for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl ( To obtain acrylic copolymers such as meth)acrylate, butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, lauryl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, etc. Commonly used acrylic monomers], acrylonitrile, vinyl acetate, etc. The acrylic copolymer (b) containing 5 to 50% by weight of styrene used in the present invention is a commonly used copolymer, except that it contains a limited amount of styrene. (a) Used in the resin composition for anticorrosive paint of the present invention
In the method for producing the copolymer (b), put an organic solvent into a four-necked flask, and add 100% of the above vinyl monomer.
It is obtained by dropping it dropwise at a constant temperature of ~140°C and copolymerizing it. The organic solvent used is
Alcohols (methanol, ethanol, propanol, butanol, etc.), acetate esters (ethyl acetate, propyl acetate, butyl acetate, etc.), alcoholic ethers (cellosolve, methyl cellosolve, etc.), ketones (methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, diethyl ketones, etc.), hydrocarbons (n
-hexane, n-heptane, n-octane, xylene, toluene, etc.). In the present invention, if the silicone-containing monomer is less than 0.1% by weight in the copolymer (a), a coating film with good rust prevention properties cannot be obtained, whereas if it exceeds 50% by weight, the rust prevention effect remains constant and the cost is reduced. becomes disadvantageous. Furthermore, if the amount of styrene in the copolymer (a) is less than 5% by weight, there will be drawbacks such as water marks on the coated surface, while if it exceeds 50% by weight, the antirust effect will decrease. Furthermore, in the copolymer (b), if the amount of styrene is less than 5% by weight, the condition of the coated surface will be poor, such as water marks, while if it exceeds 50% by weight, there will be defects such as a decrease in the antirust effect. Next, when using the acrylic copolymer (a) together with the acrylic copolymer (b), if the acrylic copolymer (a) is less than 5 parts by weight, the rust prevention effect will decrease, and if it exceeds 50 parts by weight. It has defects such as poor compatibility with Next, the present invention will be explained in more detail with reference to Examples. In the examples, all parts and percentages are expressed by weight. Example 1 (a) Synthesis of silicone-containing resin Styrene 25 parts Methacryloethyltrimethoxysilane 25 parts n-butyl acrylate 45 parts Methyl methacrylate 5 parts Tert-butyl peroctate 0.05 parts Acetic acid n- 43 parts of butyl was added, and the above mixture was added dropwise over 5 hours to the mixture, which was heated to reflux temperature under stirring while nitrogen gas was introduced. As an additional catalyst, 0.05 part of azobisisovaleronitrile was added dropwise over about 1 hour at the above temperature, and the reaction was further carried out at the above temperature for 3 hours to obtain a silicone-containing resin. The nonvolatile content of this resin was 60%, W (25° C.) measured by a Gardner-Holtz bubble viscometer, and the number average molecular weight was approximately 30,000. (B) Synthesis of acrylic resin Styrene 25 parts n-butyl acrylate 35 parts n-butyl methacrylate 40 parts azobisisobutyronitrile 0.05 parts Put 43 parts of n-butyl acetate into the four-necked flask from step 2, and introduce nitrogen gas. The above mixture was added dropwise to the mixture heated to reflux temperature over 4 hours while stirring. Azopisvaleronitrile as additional catalyst
0.05 part was added dropwise over about 1 hour at the above temperature, and the reaction was further carried out for 3 hours to obtain an acrylic resin. The nonvolatile content of this resin was 60%, and the S (25°C) number average molecular weight was about 25,000 as measured by a Gardner-Holtz bubble viscometer. A resin composition was prepared by mixing 25 parts of (a) and 75 parts of (b). Example 2 (a) Synthesis of silicone-containing resin Styrene 5 parts Methacryloethyltrimethoxysilane 50 parts 2-ethylhexyl acrylate 25 parts Methyl methacrylate 20 parts Tert-butyl peroctate 0.05 parts The above mixture was mixed in the same manner as in Example 1. Let it polymerize,
A silicone-containing resin was obtained. This resin has a non-volatile content of 60
%, number average molecular weight was approximately 30,000, and viscosity was U (25° C.) using a Gardner-Holtz bubble viscometer. (b) Synthesis of acrylic resin Styrene 50 parts n-butyl acrylate 50 parts Azobisvaleronitrile 0.05 part The above mixture was reacted in the same manner as in Example 1 to obtain an acrylic resin. This resin had a nonvolatile content of 60%, a number average molecular weight of about 30,000, and a viscosity of T (25° C.) as measured by a Gardner-Holtz bubble viscometer. 5 parts of (a) and 95 parts of (b) were mixed to prepare a resin composition. Example 3 (a) Synthesis of silicone-containing resin Styrene 50 parts 2-hydroxypropyl acrylate 20 parts Methacrylopropyltrimethoxysilane
0.1 part Methyl methacrylate 29.9 parts Azobisvaleronitrile 1 part The above mixture was reacted with 67 parts of Cellosolve in the same manner as in Example 1 except that the temperature was 135°C to obtain a silicone-containing resin. The nonvolatile content of this resin was 60%, the number average molecular weight was about 30,000, and the viscosity was R (250°C) as measured by a Gardner-Holtz bubble viscometer. (B) Synthesis of acrylic resin Styrene 5 parts Ethyl acrylate 85 parts Methacrylic acid 10 parts Tertiary butyl peroctoate 1 part The above mixture was reacted in the same manner as in Example 1, except that the temperature was 135°C with 67 parts of cellosolve. An acrylic resin was obtained. This resin had a non-volatile content of 60%, a number average molecular weight of about 20,000, and a viscosity of T (25° C.) as measured by a Gardner-Holtz bubble viscometer. 95 parts of (a) and 5 parts of (b) were mixed to prepare a resin composition. Comparative Example 1 (a) Synthesis of silicone-containing resin Styrene 60 parts Methacryloethyltrimethoxysilane 0.05 parts 2-hydroxypropyl acrylate 10 parts Methyl methacrylate 29.95 parts Azobisbutyronitrile 1 part Cellosolve using the above mixture as a solvent and temperature
A silicone-containing resin was obtained by reacting in the same manner as in Example 1 except that the temperature was 135°C. This resin has a non-volatile content of 60
%, number average molecular weight was about 20,000, and the viscosity was W (25° C.) using a Gardner-Holtz bubble viscometer. (b) Synthesis of acrylic resin Styrene 4 parts n-butyl acrylate 96 parts tert-butyl peroctate 0.05 parts The above mixture was cellulsolved in a solvent and the temperature was 135°C.
An acrylic resin was obtained by reacting in the same manner as in Example 1, except that . The nonvolatile content of this resin was 60%, the number average molecular weight was about 30,000, and the viscosity was R (25°C) using a Gardner-Holtz bubble viscometer. A resin composition was prepared by mixing 60 parts (a) and 40 parts (b). Comparative Example 2 (a) Synthesis of silicone-containing resin Styrene 4 parts Methacrylopropyltrimethoxysilane 5 parts 2-ethylhexyl acrylate 80 parts Methyl methacrylate 11 parts Azobisbutyronitrile 1 part
A silicone-containing resin was obtained by reacting in the same manner as in Example 1 except that the temperature was 135°C. This resin has a non-volatile content of 60
%, number average molecular weight was approximately 20,000, and viscosity was R (25°C) using a Gardner-Holtz bubble viscometer. (b) Synthesis of acrylic resin Styrene 60 parts n-butyl methacrylate 40 parts azobisbutyronitrile 1 part
An acrylic resin was obtained by reacting in the same manner as in Example 1 except that the temperature was 135°C. This resin has a non-volatile content of 60%,
The number average molecular weight was approximately 20,000, and the viscosity was R (25°C) using a Gardner-Holtz bubble viscometer. 4 parts of (a) and 96 parts of (b) were mixed to prepare a resin composition. Experimental Example Each resin composition obtained in Examples 1 to 3 and Comparative Examples 1 to 2 was polished on a mild steel plate (approximately 150 x 70 x 1 mm).
The coating was applied to a dry film thickness of 30μ, and after sufficiently drying, a salt spray test was conducted (JIS K 5400). The results after the 100 hour test are shown in Table 1 (adhesion deterioration width, mm). 【table】

Claims (1)

[Scope of Claims] 1 (a) 0.1 to 50% by weight of at least one silicone-containing monomer represented by the following general formula, (In the above formula, R ₁ is a hydrogen atom or a methyl group,
R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 4 carbon atoms, and n is an integer of 1 to 12. ) 5 to 50 parts by weight of an acrylic copolymer consisting of 5 to 50% by weight of styrene and 94.9% by weight or less of (meth)acrylic acid ester; and (b) 50 to 95 parts by weight of an acrylic copolymer containing 5 to 50% by weight of styrene. A resin composition for anticorrosion paint consisting of: