JPS6057469B2 - Resin composition for anticorrosion paint - Google Patents

Description

[Detailed description of the invention] The present invention relates to a resin composition for anticorrosive paint.

More specifically, the present invention relates to a resin composition for anticorrosion paint using an acrylic copolymer containing a silicone-containing monomer. Conventionally, oil-based resins, epoxy-based resins, and the like have been known as resins with excellent corrosion resistance.

However, although acrylic resins have excellent physical properties, no one with sufficient corrosion resistance has yet been obtained. Furthermore, many reports have already been made regarding silicone resins, but all of them have the drawback of poor anticorrosion ability. The present invention is aimed at improving the above-mentioned defects of acrylic resins and silicone resins, and relates to the use of a combination of a silicone-containing monomer copolymer and an acrylic copolymer as a resin composition for anticorrosive paints. There are things. That is, the present invention provides: (a) 0.1 to 5% by amount, preferably 2 to 3% by amount of at least one silicone-containing monomer represented by the following general formula;
, CH2:C-C-O-CnH2n-O-Si-0R3
1:1 (in the above formula, R is a hydrogen atom or a methyl group, R.

, R3 and R are alkyl groups having 1 to 4 carbon atoms,
n is an integer from 1 to 12. ) Styrene 5~marked weight%,
Preferably 5 to 50 parts by weight of an acrylic copolymer consisting of 15 to 94.1% by weight of (meth)acrylic acid ester and preferably 83 to 3% by weight, preferably 1
50-95 parts by weight, preferably 70 parts by weight of an acrylic copolymer containing 0-3 parts by weight and 5-5% by weight of styrene.
The present invention relates to a resin composition for anticorrosive paint containing 9 parts by weight. The silicone-containing monomer used in the present invention is a condensate of hydroxyalkyl (meth)acrylate and tetraalkoxysilane.

Examples of hydroxyalkyl (meth)acrylates include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate.
Examples include meth)acrylate and hydroxylauryl(meth)acrylate. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraproboxysilane, tetrabutoxysilane, trimethoxyethoxysilane, and dimethoxybutoxysilane. The above-mentioned silicone-containing monomer is generally obtained by an acid-catalyzed dealcoholization reaction between a hydroxyalkyl (meth)acrylate and a tetraalkoxysilane.

In addition to silicone-containing monomers and styrene, vinyl monomers to be copolymerized include vinyltoluene,
(meth)acrylic acid, (meth)acrylic acid ester [e.g. methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate Examples include acrylic monomers commonly used to obtain acrylic copolymers such as acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate], acrylonitrile, and vinyl acetate.

The acrylic copolymer containing 5 to 5 weight percent of styrene used in the present invention is a commonly used copolymer containing styrene in a limited range.

The method for producing the copolymers (a) and (x) used in the resin composition for anticorrosive paints of the present invention involves placing an organic solvent in a four-bottle flask, and heating the above vinyl monomer at a temperature of 100 to 140°C.
It is obtained by dropping the mixture at a constant temperature and copolymerizing it.

Organic solvents used include alcohols (methanol, ethanol, propanol, butanol, etc.), acetic 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 ketone, etc.), hydrocarbons (n-hexane, n-heptane, 2-octane, xylene, toluene, etc.).In the present invention, the silicone-containing monomer is a copolymer (a). If the amount is less than 0.1% by weight, a coating film with good anticorrosion properties cannot be obtained, while if it exceeds 5% by weight, the anticorrosion effect remains constant, which is disadvantageous in terms of cost.

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 on the other hand, if the amount of styrene exceeds 5% by weight, the anticorrosion effect will decrease. Furthermore, copolymer (mouth)
Also, if the amount of styrene is less than 5% by weight, the condition of the coated surface deteriorates, such as water marks, and on the other hand, if the amount of styrene exceeds 5% by weight, there are defects such as a decrease in the anticorrosion effect. Next, when using the acrylic copolymer (a) in combination with the acrylic copolymer (b), if the acrylic copolymer (a) is less than 5 parts by weight, the anticorrosion effect will decrease, and if it exceeds 5 parts by weight, they will not be compatible. It has defects such as poor performance.

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 Condensate of hydroxypropyl methacrylate and tetraethoxysilane 25 parts 2-butyl acrylate
45 parts methyl methacrylate
Part 5 tertiary butyl peroctate 0.0
5 parts Put 43 parts of butyl acetate into a 2e four-loaf flask,
The above mixture was added dropwise to the mixture heated to reflux temperature over 5 hours 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 is 60%, and W
(25°C), and the number average molecular weight was about 30,000. (
Mouth) Synthetic styrene made of acrylic resin
25 parts 2-butyl acrylate
35 parts 2-butyl methacrylate Whole part Azobisisobutyronitrile 0.05 parts 43 parts of n-butyl acetate was placed in a 2e four-neck flask, and heated to reflux temperature under stirring while nitrogen gas was introduced. The above mixture was added dropwise over 4 hours.

As an additional catalyst, 0.05 part of azobisvaleronitrile 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 an acrylic resin. The nonvolatile content of this resin is 60%, and it is S (25℃) by Gardner Holtz bubble viscometer.
, the number average molecular weight was about 25,000. A resin composition was prepared by mixing 25 parts of (a) and 75 parts of (a).

Example 2 (a) Synthesis of silicone-containing resin Styrene 5 parts; condensate of hydroxyethyl methacrylate and tetramethoxysilane 5 (2) 2-ethylhexyl acrylate 25 parts methyl methacrylate
2α■ Tertiary butyl peroctate 0
．． 05 Part i The above mixture was copolymerized in the same manner as in Example 1 to obtain a silicone-containing resin.

This resin had a nonvolatile content of 60%, a number average molecular weight of about 30,000, and a viscosity of U (25°C) as measured by a Gardner-Holtz bubble viscometer. (mouth) Synthetic styrene made of acrylic resin
(branch) part n-butyl acrylate
Inbe Azobispareronitrile
0.05 parts of 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. A resin composition was prepared by mixing 5 parts of (A) and 95 parts of (A).

Example 3 (a) Synthesis of silicone-containing resin Styrene 2-hydroxypropyl acrylate Condensate of 2-hydroxypropyl acrylate and tetraethoxysilane
0.1 part methyl methacrylate
29J 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 is 60%, the number average molecular weight is approximately 30,000,
The viscosity was R (25°C) using a Gardner Holtz bubble viscometer. (mouth) Synthetic styrene made of acrylic resin
5 parts ethyl acrylate
85 parts methacrylic acid
1 part of tert-butyl peroctoate The above mixture was reacted in the same manner as in Example 1, except that the mixture was mixed with 67 parts of cellosolve at a temperature of 135° C. to obtain an acrylic resin.

This resin had a nonvolatile content of 60%, a number average molecular weight of about 20,000, and a viscosity of T (25 viscosity C) as measured by a Gardner-Holtz bubble viscometer. A resin composition was prepared by mixing 95 parts of (A) and 5 parts of (A).

Comparative Example 1 (a) Synthetic styrene containing silicone resin 6Ciffri 2
-Condensation product of hydroxypropyl methacrylate and tetramethoxysilane 0.05 parts 2-hydroxypropyl acrylate 1α ■ Methyl methacrylate
29.95 parts Asobisbutyronitrile
A silicone-containing resin was obtained by reacting in the same manner as in Example 1, except that 1 part of the above mixture was used as cellosolve as a solvent and the temperature was 135°C.

This resin had a nonvolatile content of 60%, a number average molecular weight of about 20,000, and a viscosity of W (25°C) as measured by a Gardner-Holtz bubble viscometer. (b) Synthetic styrene in acrylic resin
4 parts n-butyl methacrylate
(branch) part n-butyl acrylate
44 parts tertiary butyl peroctate 0.05
An acrylic resin was obtained by reacting the above mixture in the same manner as in Example 1 except that the solvent was Cellosolve and the temperature was 135°C.

The nonvolatile content of this resin is 60%, the number average molecular weight is approximately 30,000,
The viscosity was S (25°C) using a Gardner Holtz bubble viscometer. A resin composition was prepared by mixing the seal part (a) and the round part (mouth). Comparative Example 2 (a) Synthesis of silicone-containing resin Styrene condensate of 4-part hydroxybutyl methacrylate and tetraethoxysilane
5 parts 2-ethylhexyl acrylate 8 metal methacrylate 1
1 part azobisbutyronitrile 1 part The above mixture was reacted in the same manner as in Example 1 except that the solvent was 67 parts cellosolve and the temperature was 135°C to obtain a silicone-containing resin.

This resin had a nonvolatile 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. (b) Synthetic styrene in acrylic resin
6(2) n-butyl methacrylate
4Cf azobisbutyronitrile
1 part of the above mixture, 67 parts of Cellosolve solvent, 1 part of temperature
An acrylic resin was obtained by reacting in the same manner as in Example 1 except that the temperature was 35°C.

This resin had a nonvolatile content of 60%, a number average molecular weight of about 20,000, and a viscosity of R (25° C.) as measured by a Gardner-Holtz bubble viscometer. A resin composition was prepared by mixing 4 parts of (A) and 96 parts of (A).

Experimental Examples Each resin composition obtained in Examples 1 to 3 and Comparative Examples 1 to 2 was applied to a polished mild steel plate (approximately 150 x 70 x 1 wm) so that the dry film thickness was 30 μm, and thoroughly dried. After that, a salt spray test was conducted (JISK54O
O).

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, ▲ mathematical formula, chemical formula,
There are tables etc. ▼ (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.) Styrene 5-50 Acrylic copolymer 5 consisting of 94.9% by weight or less of (meth)acrylic acid ester
A resin composition for an anticorrosive paint comprising 50 to 95 parts by weight of an acrylic copolymer containing 50 to 50 parts by weight of (b) styrene.