JPS6234247B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a coating resin used for concrete, mortar buildings, tiles, etc.

Paints intended for waterproofing concrete, mortar buildings, tiles, etc. are required to have good alkali resistance, water resistance, weather resistance, and pigment dispersibility, depending on the nature of the object to be coated and the purpose of use. In response to these demands, vinyl acetate resin, epoxy resin,
Paints based on copolymers of methyl methacrylate and vinyl acetate have been developed and are commercially available, and copolymers of methyl methacrylate and vinyl acetate are widely used because they are relatively inexpensive. ,
Due to the lack of pigment dispersibility and weather resistance, there are drawbacks such as color separation of the paint and deterioration (cracks) of the paint film after painting. In other words, resins that have good dispersibility for black pigments such as carbon black have poor dispersibility for white pigments such as titanium oxide, while resins that have good dispersibility for white pigments have poor dispersibility for black pigments. There are disadvantages in that the selectivity is high, color separation occurs if the paint mixture is left for a while after stirring, and a coating film with insufficient color and gloss is obtained. In order to improve this drawback, attempts have been made to copolymerize methyl methacrylate and vinyl acetate with unsaturated carboxylic acids, but unsaturated carboxylic acids such as methacrylic acid, itaconic acid, and maleic anhydride cannot be used as pigments unless used in large quantities. The dispersibility cannot be improved, and as a result, the water resistance and alkali resistance of the obtained coating film decreases, which in turn leads to a decrease in weather resistance. At present, it is not possible to obtain a resin with a good balance. In view of the current situation, the present inventors conducted intensive studies on the components to be copolymerized with methyl methacrylate and vinyl acetate, and as a result, they copolymerized an acid anhydride with a specific structure and neutralized it with a base. The present invention was completed based on the discovery that the pigment has excellent pigment dispersibility without impairing water resistance, alkali resistance, and weather resistance.

The present invention relates to (a) general formula (In the formula, R and R' are hydrogen or an alkyl group (R and
The total number of carbon atoms in R' is 5 to 15. ) Alkenyl succinic anhydride 0.1 to 5
(b) 29.9-70% by weight of vinyl acetate, (c) 25-70% by weight of methyl methacrylate, and (d) copolymerizable with each monomer mixture of (a), (b), and (c). Weight average molecular weight obtained by radical polymerization of 0 to 20% by weight of other unsaturated monomers
30,000 to 100,000 copolymer is neutralized with a base, and at least a portion of the acid anhydride is obtained as a salt, and the resin has excellent pigment dispersibility.

Specific examples of alkenyl succinic anhydride represented by the general formula [] include octenyl succinic anhydride,
There is dodecenyl succinic anhydride. These acid anhydrides are used to improve pigment dispersibility and weather resistance (cracking resistance), and the amount used is 0.1 to 5% by weight, preferably 1 to 3% by weight in the copolymer. be. The amount of vinyl acetate to be copolymerized with alkenyl succinic anhydride is 29.9 to 70% by weight in the copolymer; if it is less than 29.9%, painting workability will be poor and the flexibility of the coating will be reduced. If the amount exceeds %, the weather resistance, water resistance, and alkali resistance of the coating film will decrease. The amount of methyl methacrylate used to copolymerize with these is 25 to 70% by weight; if it is less than 25%, the weather resistance will deteriorate and the toughness of the coating film will be impaired, and if it is more than 70%, the coating workability will be impaired. As the coating deteriorates, the coating becomes hard and brittle.

Furthermore, in order to impart various properties to the copolymer of the present invention, various monomers other than the above-mentioned monomers may be used in combination within the range of 0 to 20% by weight.

Examples of the monomer include (a) alkyl esters of α/β monoethylenically unsaturated carboxylic acids, such as methyl acrylate, ethyl (meth)acrylate, and (meth)acrylic acid n;
-butyl, i-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)
t-Butyl acrylate, (meth)acrylic acid 2
- Ethylhexyl, lauryl (meth)acrylate, sec-lauryl (meth)acrylate, stearyl (meth)acrylate (b) Vinyl aromatic compounds such as styrene, vinyltoluene, α-methylstyrene (c) Organic nitrile such as (meth) ) acrylonitrile (d) α/β monoethylenically unsaturated carboxylic acid amide or α/β monoethylenically unsaturated carboxylic acid amide alkyl-substituted, hydroxyalkyl-substituted and alkoxy-substituted products such as (meth)acrylamide, N-methylol (meta)
Acrylamide, N-butoxymethyl (meth)
Acrylamide (E) Hydroxyalkyl ester of α/β monoethylenically unsaturated carboxylic acid, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate (H) α・Monoalkyl or dialkyl esters of β-monoethylenically unsaturated dicarboxylic acids, such as diethyl fumarate, diptyl fumarate,
Monoethyl itaconate, diethyl itaconate,
Monobutyl itaconate, dibutyl itaconate,
Dibutyl maleate (t) Saturated branched fatty acid vinyl e.g. Veo Va10 (Ciel Chemical Co., Ltd.) (h) Adduct of glycidyl ester of tertiary synthetic saturated carboxylic acid and α/β monoethylenically unsaturated carboxylic acid (li) α - β-monoethylenically unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, itaconic acid, crotonic acid, etc.

The coating resin of the present invention is produced by radical copolymerization of the above-mentioned monomers using a conventional solution polymerization method to produce a copolymer with a weight average molecular weight of 30,000 to 100,000, which is then neutralized with a base to produce an acid-copolymer. At least a portion of the anhydride is obtained as a salt. Solvents used during solution polymerization include hydrocarbons such as toluene and xylene,
Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; acetic acid esters such as ethyl acetate and butyl acetate; cellosolve solvents such as methyl cellosolve, ethyl cellosolve, and cellosolve acetate; or alcohols such as ethanol, isopropyl alcohol, and n-butanol. can be used. As the polymerization initiator, organic peroxides such as lauroyl peroxide and benzoyl peroxide, and azo initiators such as azobisisobutyronitrile can be used. Furthermore, chain transfer agents such as mercaptans can also be used if necessary. The copolymer obtained by radical copolymerization has a weight average molecular weight of 30,000 to 100,000, particularly preferably 40,000 to 100,000.
It is 80000. If it exceeds 100,000, the viscosity of the paint becomes high and painting work becomes difficult, while if it is less than 30,000, the mechanical performance when formed into a coating film becomes insufficient. In order to further improve pigment dispersibility, the coating resin of the present invention is characterized in that a copolymer having the above-mentioned components is neutralized with a base to convert at least a portion of the acid anhydride into a salt. There is. The bases used at this time are ammonia, caustic soda,
Inorganic bases such as caustic potash, or alkylamines such as monomethylamine, diethylamine, triethylamine, trimethylamine, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, dimethylaminoethanol, diethylaminoethanol, or other nitrogen-containing Bases are used. The degree of neutralization may be appropriately selected from partial neutralization to complete neutralization depending on the required degree while checking the balance between pigment dispersibility and water resistance.

By appropriately blending a solvent, a pigment, a plasticizer, an anti-sagging agent, an anti-settling agent, an antifoaming agent, etc. with the resin for coating of the present invention, it can be used as a waterproof coating for exterior materials such as concrete, mortar buildings, and roof tiles. You can get something. The coating is performed by methods such as brush coating, roller coating, and spray coating.

In the following examples, "parts" indicate parts by weight.

Example 1 225 parts of toluene and 250 parts of methyl methacrylate were placed in a reaction vessel equipped with a thermometer, reflux condenser, and stirrer.
1 part, 220 parts of vinyl acetate, 5 parts of octenyl succinic anhydride, and 2 parts of asobisisobutyronitrile, and the temperature was raised to 80°C, after which the polymerization rate was 100%.
Polymerization was carried out for 15 hours while adding azobisisobutyronitrile so that the weight average molecular weight was 58,000.
of resin was obtained. At the end of the polymerization, 1.7 parts of β-dimethylaminoethanol and 275 parts of toluene were added to obtain a transparent resin solution. The resulting resin solution has a viscosity of
8000cps (B type viscosity), heating residue 50.1%, acid value 2.4
It had To evaluate the pigment dispersibility of this resin, 2 parts of carbon black (Mitsubishi Kasei Corporation MA-100), 20 parts of xylene, and 100 parts of glass beads were added to 40 parts of the above resin using a paint shaker. Dispersion was allowed for 2 hours. The obtained coating material was applied onto a glass plate to a film thickness of 50 μm, and the dispersion state and gloss were measured. The dispersibility was good and the coating had a gloss value of 80 (60 degree gloss). In addition to this paint, a white paint (P/B=
0.8/1 titanium oxide) was spray-painted on a slate board to a film thickness of 50 μm, and after air drying, the water resistance, alkali resistance, and weather resistance were evaluated. It had alkali resistance and weather resistance.

Comparative Example 1 Polymerization was carried out in the same reaction vessel as in Example 1 using acrylic acid instead of the octenyl succinic anhydride in Example 1 to obtain a resin with a weight average molecular weight of 61,000. However, it was not neutralized with dimethylaminoethanol at the end of the polymerization. The resulting resin solution has a viscosity of
It had 12,000 cps, a heating residue of 49.7%, and an acid value of 3.8. Using the obtained resin, the pigment dispersibility was evaluated using carbon black as the pigment in the same manner as in Example 1. The dispersibility was poor and the gloss value was as low as 55, indicating that the resin was not useful as a building material.

Example 2 In a reaction vessel similar to Example 1, 225 parts of toluene,
250 parts of methyl methacrylate, 225 parts of vinyl acetate, n
17.5 parts of -butyl acrylate and 7.5 parts of dodecenyl succinic anhydride were charged and polymerized using azobisisobutyronitrile as a polymerization initiator in the same manner as in Example 1 to obtain a resin having a weight average molecular weight of 57,000. At the end of the reaction, 3 parts of triethylamine and 275 parts of toluene were added to obtain a transparent resin solution. The resulting resin solution had a viscosity of 10,000 cps, a heating residue of 49.8%, and an acid value of 3.2. When the pigment dispersibility of this resin in carbon black was evaluated in the same manner as in Example 1, the pigment dispersibility was good and the resin had a gloss value of 81.

Further, a white paint was prepared in the same manner as in Example 1, and the pigment dispersibility in titanium oxide was also good. In order to examine the film performance of this paint, evaluation was carried out in the same manner as in Example 1, and it was found to have good water resistance, alkali resistance, and weather resistance for use as a building material.

Comparative Example 2 Polymerization was carried out in the same reaction vessel as in Example 1 using methacrylic acid instead of dodecenyl succinic anhydride in Example 2 to obtain a resin with a weight average molecular weight of 63,000. However, it was not neutralized with triethylamine at the end of the polymerization. The resulting resin solution has a viscosity of
It had 13,000 cps, a heating residue of 50.1%, and an acid value of 4.8.

When this resin was evaluated for pigment dispersibility in carbon black in the same manner as in Example 1, the dispersibility was poor and the gloss value was as low as 50, indicating that the resin was not useful as a building material.

Claims (1)

[Claims] 1 (a) General formula (In the formula, R and R' are hydrogen or an alkyl group (R and
The total number of carbon atoms in R' is 5 to 15. ) Alkenyl succinic anhydride 0.1 to 5
(b) 29.9-70% by weight of vinyl acetate, (c) 25-70% by weight of methyl methacrylate, and (d) copolymerizable with each monomer mixture of (a), (b), and (c). Weight average molecular weight obtained by radical polymerization of 0 to 20% by weight of other unsaturated monomers
30,000 to 100,000 copolymer is neutralized with a base, and at least a portion of the acid anhydride is obtained as a salt. A method for producing a coating resin with excellent pigment dispersibility.