JPH0668090B2 - Paint for porous building materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating material for porous building materials.

[Conventional technology]

Conventionally, there has been a paint composed of a moisture-curing urethane resin adjusted to have a constant viscosity as a paint for a porous building material such as lightweight foamed concrete, and there is a technique of applying this and allowing it to permeate the inside of a molded product to cure it (for example, JP-A-57-50578
Gazette).

[Problems to be solved by the invention]

However, this technique has a problem that it is difficult to obtain a product having a good finished appearance because the surface coverage is not sufficient, and yellowing or deterioration easily occurs due to the influence of ultraviolet rays or the like.

[Means for solving problems]

The present inventors have accomplished the present invention as a result of intensive research aimed at obtaining a coating material for a porous building material, which has a good finished appearance and is hardly yellowed or deteriorated by ultraviolet rays or the like.

A solvent, an acrylic copolymer (A) having a glass transition point of −20 to 50 ° C., and a polymer (B) different from the copolymer (A), and the copolymer (A) and the polymer (B) A coating material for a porous building material, characterized in that a vehicle is a dispersion formed by polymerization in the presence of the solvent and in which the polymer (B) is dispersed.

As the acrylic copolymer (A) in the present invention, an alkyl (meth) acrylate and optionally a mono (meth) acrylate of a hydroxyl group-containing monomer and / or another vinyl monomer which is copolymerizable with the above monomer Examples include (co) polymers from the body.

The alkyl (meth) acrylate has an alkyl group having 1 to 20 carbon atoms, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate. , n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Examples thereof include octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylate of a synthetic monoalcohol obtained by the oxo method and the Ziegler method, and a mixture of two or more thereof. Of these, preferred are (meth) acrylates having an alkyl group with 1 to 14 carbon atoms, and particularly preferred are methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl. (Meth) acrylate and lauryl (meth) acrylate.

As the mono (meth) acrylate of the hydroxyl group-containing monomer, glycols having 2 to 4 carbon atoms or alkylene oxides thereof (alkylene oxides having 2 to 4 carbon atoms such as ethylene oxide and propylene oxide) in low mole (eg, 1 to 6 mole) addition (Meth) acrylates of substances (ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, butanediol, etc.) and these 2 kinds or more. Of these, preferred is ethylene glycol,
Mono (meth) acrylates of diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and butanediol are preferred, with ethylene glycol and propylene glycol monomethacrylate being particularly preferred.

Other vinyl monomers copolymerizable with the above monomers include lipophilic monomers such as aromatic unsaturated hydrocarbons (styrene,
α-methylstyrene, vinyltoluene, etc.), vinyl ester (vinyl acetate, vinyl propionate, etc.), unsaturated polycarboxylic acid ester (dialkyl maleate, dialkyl itaconate, etc.), unsaturated halogenated hydrocarbons (vinyl chloride, chloride) Vinylidene, etc.), unsaturated nitriles ((meth) acrylonitrile, etc.), and hydrophilic monomers such as unsaturated carboxylic acids ((meth) acrylic acid, crotonic acid, etc.), unsaturated carboxylic acid amides ((meth) acrylamide, etc.) And mixtures of two or more of these. Of these, preferred are aromatic unsaturated hydrocarbons, vinyl ester unsaturated polycarboxylic acid esters and unsaturated carboxylic acids, and particularly preferred are aromatic unsaturated hydrocarbons, vinyl esters and unsaturated carboxylic acids.

Based on the weight of the copolymer, the content of each monomer of the acrylic copolymer (A) is usually 50 to 100% for the alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms,
Preferably 60-90%, hydroxyl group-containing monomer is usually 0-20
%, Preferably 5 to 15%, and other vinyl monomers are usually 0 to 30%, preferably 5 to 20% (when other vinyl monomers are lipophilic monomers, usually 0 to 30%, Preferably 5 to 20
%, In the case of a hydrophilic monomer, usually 0 to 5%, preferably 0
~ 2%).

Examples of the acrylic copolymer (A) include the following. However, the present invention is not limited to this.

No.1: Copolymer of n-butyl methacrylate, ethyl acrylate and hydroxyethyl methacrylate (60: 30: 1
0) No.2: Copolymer of n-butyl methacrylate and hydroxyethyl methacrylate (95: 5) No.3: Copolymer of methyl methacrylate, butyl acrylate and hydroxypropyl methacrylate (50:35:
15) No.4: Copolymer of methyl acrylate, methyl methacrylate and styrene (80:10:10) No.5: Copolymer of n-butyl methacrylate, methyl acrylate and acrylic acid (87: 10: 3) ) The numbers in parentheses indicate the weight content in the copolymer.

The glass transition temperature of acrylic copolymer (A) is -20 to 50 ° C.
It is preferably -15 to 40 ° C. When the glass transition point is lower than -20 ° C, the resin strength is lowered, and when it exceeds 50 ° C, the resin becomes hard and brittle, and both are not suitable as a vehicle for a coating, which is not preferable.

In the present invention, the polymer (B) different from the acrylic copolymer (A) preferably has low crystallinity, is soluble in an organic solvent, and has flexibility in a normal temperature range. Specific examples include the following resins and polymers.

Polymerizable resin (1) Ethylene / vinyl acetate copolymer Vinyl acetate content 10-46% by weight, melt index 3
~ 500, (for example, Evaflex # 220; Mitsui Polychemicals Co., Ltd. products, etc.).

(2) Ethylene / (meth) acrylate copolymer Ethylene / ethyl acrylate copolymer (for example, EEA; product of Nippon Unicar Co., Ltd.).

(3) Styrin / diene block copolymer or hydride thereof Styrene / butadiene block copolymer (for example, Tuffprene A; product of Asahi Kasei Co., Ltd.). Styrene-isoprene block copolymer (eg Kraton TR-110
7, Ciel Chemical Co., Ltd. products, etc.). Hydrogenated styrene-isoprene copolymer (eg Kraton G; product of Ciel Chemical Co., Ltd.).

(4) Isobutylene Polymer Polyisobutylene obtained by ion-polymerizing isobutylene (for example, Vistanetx LM; manufactured by Esso Petrochemical Co., Ltd.).

Condensation-type resin (5) Polyester resin Amorphous saturated linear polyester resin (for example, Byron # 200; manufactured by Toyobo Co., Ltd.) and saturated linear polyester resin are, for example, basic synthetic resin chemistry <new edition > (Published by Gihodo on November 20, 1975).

As an addition polymerization type resin, (1) polyurethane resin, high molecular weight polyol (molecular weight per hydroxyl group is usually 250 to 250)
0, preferably 300 to 1500 polyether polyol, polyester polyol, etc.), diisocyanate and optionally a chain extender and a compound selected from the group consisting of low molecular weight polyfunctional active hydrogen-containing compounds (Samprene TCM-310). , Sampren IB
-1700; Sanyo Kasei Co., Ltd., etc .; Japanese Patent Application No. 59 for polymer polyols, diisocyanates and chain extenders
-64208 and Japanese Patent Application No. 60-99148, and examples of low molecular weight polyfunctional active hydrogen-containing compounds include trifunctional or higher functional low molecular weight polyols (glycerin, trimethylolpropane, etc.), polyamines, aminos. Alcohol and the like; the terminal of the polyurethane resin is not particularly limited, and examples include those having an OH terminal.

Among these, ethylene / vinyl acetate copolymer, ethylene (meth) acrylate copolymer, polyester resin and polyurethane resin are preferable, and ethylene / vinyl acetate copolymer, polyester resin and polyurethane resin are particularly preferable. is there.

The dispersion in the present invention is a dispersion of the polymer (B) different from the copolymer in the organic solvent solution of the acrylic polymer (A) in the form of fine particles. The weight ratio of (A) to (B) in the dispersion is usually 50:50 to 95: 5, preferably
It is between 55:45 and 90:10. The weight ratio of (B) to (A) is
If it exceeds 50, the dispersion tends to be unstable, and if it is less than 5, the effect of the dispersion when used as a vehicle of a coating material for porous building materials is deteriorated.

The dispersion according to the present invention can be obtained by copolymerizing the above monomers in an organic solvent in the presence of the polymer (B) with a radical initiator. The organic solvent used at this time is not particularly limited, but those which can dissolve both the acrylic polymer (A) and the polymer (B) different therefrom are preferable, for example, benzene, toluene, xylene, cyclohexane, cyclooctane and the like. Hydrocarbons, acetic acid esters such as methyl acetate, ethyl acetate, n-butyl acetate and cellosolve acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclooctanone and mixed solvents of two or more of these can give. Preferred among these are toluene and cyclohexane for hydrocarbons, ethyl acetate and n-butyl acetate for acetates, methyl ethyl ketone and methyl isobutyl ketone for ketones, and particularly preferred are toluene, cyclohexane and
It is n-butyl acetate, methyl ethyl ketone, and a mixed solvent of two or more thereof.

The radical initiator is preferably an oil-soluble one, for example, a peroxide initiator such as benzoyl peroxide, lauroyl peroxide, tertiary butyl hydroperoxide, cumene hydroperoxide, or azobisisobutyronitrile, azobis. Examples thereof include azo initiators such as isovaleronitrile and azobisisocyanovaleric acid. The amount of the radical initiator used is usually 0.01 to 5.0% based on the total weight of the monomers. The polymerization temperature needs to be selected depending on the decomposition temperature of the initiator, but is usually in the range of 50 to 150 ° C. The polymerization time is usually 1 to 24 hours. Further, a known chain transfer agent can be used if necessary for adjusting the polymerization degree of the copolymer. Examples of chain transfer agents include mercaptans such as dodecyl mercaptan and n-butyl mercaptan,
Alternatively, a halogen compound such as carbon tetrachloride can be used.

The solid content of (A) and (B) in the dispersion is usually 20-60.
%, Preferably 30 to 50%.

Inorganic pigments are usually used in the paint of the present invention. Examples of the inorganic pigment include titanium oxide, barium sulfate, calcium carbonate, alumina, silica, clay, talc, mica, asbestine, and mixtures of two or more thereof. Also, if necessary, solvent, colorant, dispersant,
Stabilizers, defoamers, thickeners, leveling agents, etc. may also be included.

In addition, the coating composition of the present invention may be used in combination with a crosslinking agent for the purpose of improving the strength and durability of the coating film (the monomer of (A) has a hydroxyl group and / or a carboxyl group-containing monomer). Is used). As the cross-linking agent, for example, polyisocyanate, or amino resin such as alkoxylated methylol melamine, alkoxylated methylol urea, or alkoxylated methylol guanamine can be used.

The formulation examples of the coating material of the present invention are as follows. % Is% by weight.

Polymer / polymer dispersion (per solid content) 10-50% (preferably 15-40%) Inorganic pigment 5-40% (preferably 10-35%) Solvent 30-30% (preferably 40-) 70%) Additives (dispersing agent, defoaming agent, etc.) Appropriate amount Curing agent Appropriate amount The coating material of the present invention uses a polymer / polymer dispersion as a vehicle, an inorganic pigment, and optionally other components in a usual mixing device ( For example, it can be obtained by dispersing and mixing using a ball mill, kneader or sand grinder.

As the porous building material to which the coating material of the present invention is applied, lightweight foamed concrete, silica board, asbestos board, slate board,
Examples include gypsum board or mortar board. It can also be used for the lightweight cellular concrete described in JP-A-57-50578.

The coating amount is usually 200 to 1000 g / m ^2, preferably 400 to 800 / m ²
Is.

Examples of the coating method of the paint of the present invention include brush coating,
It can be applied by a method such as roll coating, spray coating, flow coating, or dipping, and is not particularly limited.

Drying conditions are usually 1 to 2 days at room temperature and 30 minutes to 1 at 50 ° C.
It's time.

〔Example〕

The present invention will be further described below with reference to examples, but the present invention is not limited thereto. "Parts" in the examples are parts by weight.

Example 1 800 parts of toluene, ethylene, vinyl acetate copolymer (Evaflex # 220, vinyl acetate content 28%, melt) were placed in a 3 four-necked flask equipped with a stirrer, thermometer, cooling tube, dropping funnel and N ₂ gas introduction tube. 200 parts of Index 150; manufactured by Mitsui Polychemical Co., Ltd. was charged and melted at 80 ° C.
Then n-butyl methacrylate 610 in N ₂ gas stream
Parts, 290 parts of ethyl acrylate, 100 parts of 2-hydroxyethyl methacrylate and 5 parts of azobisisobutyronitrile were added dropwise at 80 to 90 ° C. over 4 hours.
The polymerization reaction is completed by stirring and aging at 90 to 95 ° C for 6 hours, and the semi-transparent syrup-like solid content is 45.2% and the viscosity is 2400 cps.
A dispersion solution of / 25 ° C was obtained. This dispersion was extremely stable with no change in appearance and properties even after storage at 40 ° C for 3 months.

Next, 1000 parts of the above dispersion liquid, 180 parts of rutile type titanium oxide, 270 parts of precipitating barium sulfate, 20 parts of a dispersant (Tenro # 70; manufactured by San Nopco Ltd.) and 550 parts of butyl acetate were dispersed and mixed in a ball mill for 24 hours. Then, a coating solution was prepared.

Next, 1000 parts of this coating solution, isophorone diisocyanate derivative (Takenate D-140N; Takeda Pharmaceutical Co., Ltd.)
60 parts, methyl ethyl ketone 100 parts, and methyl isobutyl ketone 100 parts were uniformly mixed to prepare a paint. This paint is applied to the surface of lightweight foamed concrete (specific gravity of about 0.6) molded to a thickness of about 50 mm by the flow coating method, at about 50 ° C.
Dried in warm air for 30 minutes. The resulting coated surface had a very good finished appearance with almost no pinholes.

In order to check the water resistance of the coated surface of this coated product, the surface other than the coated surface was coated with a waterproof silicone caulking agent, immersed in water for 10 days, and the rate of weight increase was measured 1.
It was 08%, showing that it has excellent waterproofness. In addition, no change in appearance such as yellowing, cracking, and peeling was observed even after 1000 hours of exposure of the painted surface to a Sunshear weatherometer, indicating good weather resistance.

Example 2 A polytetramethylene glycol (molecular weight 2000), isophorone diisocyanate, 1.4-butanediol and trimethylolpropane was placed in a three-necked three-necked flask equipped with a stirrer, a thermometer, a cooling tube, a dropping funnel and a N ₂ gas introducing tube. A solution consisting of 200 parts of a polyurethane resin having an OH group at its end, 400 parts of toluene and 400 parts of methyl ethyl ketone was charged, and n-butyl methacrylate was added while passing N _2.
800 parts, methyl methacrylate 120 parts, 2-hydroxyethyl methacrylate 80 parts and azoisobutyronitrile 4
Part of the mixture was added dropwise at 80-90 ° C over 4 hours,
The polymerization reaction was completed by aging at ˜95 ° C. for 6 hours to obtain a dispersion having a solid content of 45.2% and a viscosity of 4200 cps / 25 ° C. This dispersion was also extremely stable with no change in appearance and properties even after storage at 40 ° C for 3 months.

Thereafter, in the same manner as in Example 1, preparation of a coating solution, preparation of a coating, coating on lightweight foam concrete and drying were carried out to obtain a coated article. The appearance of the painted surface was very good with almost no pinholes.

When the waterproofness and weather resistance of the coated surface were examined in the same manner as in Example 1, the weight increase rate after immersion in water for 10 days was 0.98%, indicating that the coating film remained exposed even after 1000 hours of the Sunshine Weatherometer. There was almost no yellowing and no cracking or peeling was observed.

〔The invention's effect〕

The coating material of the present invention has an effect that a coating having excellent waterproofness, finished appearance and weather resistance can be applied only by applying a single layer on the surface of a porous building material such as lightweight foamed concrete.

In addition, the coating with the paint of the present invention seems to be performed conventionally,
It is economically advantageous because the process can be simplified as compared with a method in which the surface of the porous building material is first treated with a sealer such as moisture-curing urethane and then a paint is applied on the surface to finish the surface.

Claims (3)

[Claims] 1. A solvent, an acrylic copolymer (A) having a glass transition point of -20 to 50 ° C., and a polymer (B) different from the copolymer (A), wherein the copolymer (A) is A coating material for a porous building material, characterized in that a dispersion is formed by polymerization in the presence of the polymer (B) and the solvent and in which the polymer (B) is dispersed as a vehicle. 2. A polyurethane resin, an ethylene / vinyl acetate copolymer, an ethylene / (meth) acrylate copolymer, a polyisobutylene resin, a polyester resin and a styrene / diene block copolymer or a hydride thereof. The coating composition according to claim 1, which is a polymer selected from the group consisting of: 3. The paint according to claim 1 or 2, wherein the weight ratio of (A) and (B) is 50:50 to 95: 5.