JPH05140408A - Composition - Google Patents

Abstract

(57) [Summary] [Objective] To provide a composition effective as various industrial materials such as a sealer or the like which is applied to the surface of a porous inorganic plate in advance so that the surface of the inorganic plate can be effectively finished. That is. [Structure] Modified polyvinyl alcohol (A) containing 0.01 to 5 mol% of a silyl group in the molecule, and a glass transition temperature (Tg) of 5 ° C ≤ Tg ≤ 100 ° C and an average particle diameter of 0.2 µm or more. A composition comprising an aqueous emulsion (B) having a water-insoluble polymer as a dispersoid and having a solid content ratio (A) / (B) on a weight basis of 5/95 to 50/50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition comprising a specific modified polyvinyl alcohol (A) and a specific aqueous emulsion (B), and more specifically to various industries including sealer compositions for porous inorganic plates. It relates to a composition effective as a material. Inorganic boards such as calcium silicate board, gypsum board, lightweight aerated concrete (ALC) board and rock wool board are all porous and therefore have low surface strength and easily absorb water. Therefore, if the surface is finished with makeup as it is, the surface powder is mixed with the finishing material for a beautiful finish, the blemishes ooze out from the inorganic plate, or it peels off immediately even after a good finish, or freezes if it absorbs water or absorbs moisture. There is a problem in terms of beauty and durability, such as the finishing material peeling off due to repeated melting. For the purpose of preventing these troubles, a sealer is applied to the surface of such an inorganic plate before finishing it.
The application of this sealer may be performed in the inorganic plate manufacturing line of the factory, or may be performed during the finishing process of the construction site, but the present invention is a composition particularly effective when performing the sealer process in the inorganic plate manufacturing line of the factory. It is about things.

[0002]

2. Description of the Related Art Inorganic plates that have been subjected to a sealer treatment are left for several months as commercial products in that state, or after several months, rainwater, and outside air before being used for construction and makeup finishing. May be exposed to
Therefore, the properties required for such a sealer are roughly classified into three, namely, the effect of reinforcing the surface of the inorganic plate, the water-stopping performance, and the adhesion to the finishing material. Conventionally, solvent type sealers such as urethane resin type, epoxy resin type and vinyl chloride resin type have been mainly used, and as a typical one, a moisture curing type urethane resin type sealer is known.

[0003] This product has a good surface layer reinforcing effect and water blocking performance, but when left for a long time while being treated with a sealer, the coating film is excessively hardened and the adhesion to the finishing agent, which was initially good, is lowered. In addition to the problem that it comes up, there is a safety and health problem because it is a solvent system. Further, since the solvent used as the diluent is expensive and is a mixed solvent, there is a problem that the cost is inevitable even if recovery and reuse are taken into consideration.

On the other hand, as a typical water-based sealer, one having an acrylic emulsion as a main component is known. Although this has the advantage of not using a solvent at all, the surface layer reinforcing effect of the inorganic plate is extremely small,
When the finishing treatment is performed, there is no problem for a while, but after several months, the surface layer of the inorganic plate may be peeled off, and there is a problem that it cannot be used stably. Also, regarding water-stopping performance, it is difficult to obtain a sufficiently satisfactory one, even though it is a hydrophobic resin by nature. The cause is
The thickening agent used together reduces the water resistance of the coating film,
Defects during coating are more likely to occur than solvent-based sealers. That is, relatively large pores are scattered on the surface layer of the porous inorganic plate, and when the sealer liquid is applied, the sealant liquid concentrates and permeates into that part, so that it is difficult to form a uniform coating liquid film, and before drying. This is probably due to the holes.

As a method of improving the drawbacks of such an aqueous sealer, a method of using polyvinyl alcohol (hereinafter abbreviated as PVA) and an aqueous emulsion in combination has been proposed (see Japanese Patent Laid-Open No. 53-97018). . However, even with this method, the fact is that the above-mentioned inorganic plate reinforcing effect and water blocking performance have not been sufficiently improved. Further, an aqueous sealer made of a modified PVA having a silyl group in the molecule (see JP-A-58-167485) or an aqueous sealer made of a synthetic resin emulsion containing a modified PVA having a silyl group in the molecule as an emulsifier (Japanese Patent Application Laid-Open No. 2006-242242) Japanese Patent Laid-Open No. 58-171457) is also known. These water-based sealers, compared to conventional water-based sealers, are significantly improved in terms of the surface layer reinforcing effect of the inorganic plate or the adhesiveness with the inorganic plate, which is excellent in that respect, but the water-stopping performance is not always required. It is not sufficient, and when the surface decorative finishing material is an acrylic paint, there is a problem that the adhesion with the finishing treatment agent may be lowered.

Further, in order to solve such a problem, an aqueous sealer containing an epoxy emulsion as a main component has been proposed. However, since the sealer is a two-pack type sealer, there is a problem of workability and a possibility of deterioration. There is a limit on the usage time, which is a serious problem in practice. Besides, (1)
PVA (A) having 0.01 to 5 mol% of silyl group and acrylic emulsion (glass transition temperature 5 to 50 ° C) (B)
The solid content ratio (A) / (B) based on weight
= 5/95 to 50/50 Sealer composition for porous inorganic plate (see JP-A-62-161878),
(2) PVA (A) having 0.01 to 5 mol% of silyl group
And acrylic emulsion (glass transition temperature 5 ~ 50 ℃)
(B) and a water-proofing agent (C), and a solid content ratio (A) / (B) = 5/95 to 50/50 on a weight basis.
(A) / (C) = 99.5 / 0.5 to 10/90 Sealer composition for porous inorganic plates (JP-A-63-13908)
No. 3), (3) PVA (A) having 0.01 to 5 mol% of silyl group and acrylic emulsion (glass transition temperature exceeding 50 ° C. and 120 ° C. or less) (B), which is a solid by weight. Mixing ratio (A) / (B) = 5/95 ~
A sealer composition for a porous inorganic plate having a ratio of 50/50, a sealer composition obtained by using a waterproofing agent (C) in combination therewith (see JP-A-64-14182), and (4) a silyl group Porous inorganic plate comprising PVA (A) having 0.01 to 5 mol% and polyvinyl acetate emulsion (B), and having a solid content blending ratio (A) / (B) = 5/95 to 50/50 on a weight basis. Sealer compositions and water resistant agent (C) (A) / (C) = 99.5 / 0.5-10 / 9
Sealer composition used in combination at a ratio of 0 (Japanese Patent Laid-Open No. 63-
No. 139082) is known. All of these sealer compositions have excellent performance, but further high performance sealers are required in terms of surface layer reinforcing effect and water stoppage.

[0007]

The object of the present invention is to provide a water-based system which has no problem in terms of safety and hygiene, moreover, coating defects are less likely to occur even in the case of a single coating, and the surface layer reinforcing effect and water-stopping performance are excellent. It is an object of the present invention to provide a composition which is comparable to a solvent-based sealer and whose adhesiveness to a finishing material is not deteriorated even if it is left for a long time while being treated with a sealer. Another object of the present invention is to coat a plate having a high water content with a sealer, and even when the plate and the sealer are dried at the same time, coating defects are less likely to occur, and the surface layer reinforcing effect and the water stopping performance are obtained. To provide a composition which is comparable to a solvent-based sealer and whose adhesion to a finishing material is not deteriorated even when left for a long time while being treated with a sealer. Still another object of the present invention is to prevent coating defects from occurring even in the case of a single coating, to further improve the surface layer reinforcing effect, the waterproof performance and the adhesion to the finishing material, and to improve the conventional sealer composition. It is an object of the present invention to provide a composition which can be applied to a high density porous inorganic plate which was difficult. The present inventors have earnestly studied to overcome the various drawbacks of the prior art and achieve the above-mentioned object. As a result, a modified polyvinyl alcohol containing a silyl group in the molecule, a glass transition temperature of 5 to 100 ° C., and an average particle size of 0.
A composition containing an aqueous emulsion containing a water-insoluble polymer having a size of 2 μm or more as a dispersoid as a main component, and a composition obtained by further adding a water-proofing agent to the composition have physical properties suitable for the above purpose. I found it. The present invention has been completed based on such findings.

That is, the present invention has a silyl group in the molecule.
A modified polyvinyl alcohol (A) containing 0.01 to 5 mol% and an aqueous emulsion (B) containing a water-insoluble polymer having a glass transition temperature of 5 to 100 ° C. and an average particle diameter of 0.2 μm or more as a dispersoid, The present invention provides a composition characterized in that a solid content ratio (A) / (B) on a weight basis is 5/95 to 50/50, and the composition has water resistance of the above component (A). It also provides a composition comprising the agent (C).

The modified polyvinyl alcohol (modified PVA) which is the component (A) of the composition of the present invention may be any one as long as it contains a silyl group in the molecule, but the silyl group contained in the molecule is alkoxyl. A group having a reactive substituent such as a group, an acyloxyl group, a silanol group which is a hydrolyzate of these groups, or a salt thereof is particularly preferably used. As a method for producing such modified PVA,
Method of introducing a silyl group into PVA or modified polyvinyl acetate containing a carboxyl group or a hydroxyl group by post-modifying with a silylating agent, and copolymerization of vinyl ester and silyl group-containing olefinically unsaturated monomer Examples thereof include a method of saponifying the combined product, and a method of saponifying a polyvinyl ester having a silyl group at the terminal obtained by polymerizing a vinyl ester in the presence of a mercaptan having a silyl group.

In the above method, for example, the silylating agent is dissolved in an organic solvent which does not react with the silylating agent (benzene, toluene, xylene, hexane, heptane, ether, acetone or the like), and the resulting solution is added. Powdered PVA or the above modified polyvinyl acetate is suspended under stirring, and the silylating agent is allowed to react with PVA or the above modified polyvinyl acetate at a temperature ranging from room temperature to the boiling point of the silylating agent, or further alkali A silyl group-containing modified PVA can be obtained by saponifying a vinyl acetate unit with a catalyst or the like.

Examples of the silicifying agent used in the post-modification include organohalogenosilanes such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, diphenyldichlorosilane and triethylfluorofuran, trimethylacetoxysilane, dimethyldiacetoxysilane. And other organosilyl esters, trimethylmethoxysilane, dimethyldimethoxysilane, and other organoalkoxysilanes, trimethylsilanol, diethylsilanediol, and other organosilanols, N-aminoethylaminopropyltrimethoxysilane, and other aminoalkylsilanes, trimethylsilylisoanate, etc. Organosilyl isocyanate and the like. The introduction rate of the silylating agent, that is, the degree of modification can be arbitrarily adjusted depending on the amount of the silylating agent used and the reaction time. Also, a modified PV containing a silyl group obtained
The degree of polymerization and saponification of A are the degree of polymerization of PVA used,
The degree of saponification or the degree of polymerization of the modified polyvinyl acetate and the saponification reaction can be arbitrarily adjusted.

In the above method, that is, in the method of saponifying a copolymer of a vinyl ester and a silyl group-containing olefinic unsaturated monomer, for example, the vinyl ester and the silyl group-containing olefinic unsaturated monomer are used in alcohol. By copolymerizing a monomer with a radical initiator, and then adding an alkali or acid catalyst to the alcohol solution of the resulting copolymer, and saponifying the copolymer, the desired silyl group-containing content is obtained. Modified PVA can be obtained. Examples of the vinyl ester used in this method include vinyl acetate, vinyl propionate, vinyl formate and the like, but vinyl acetate is preferable for practical use. Examples of the silyl group-containing olefinically unsaturated monomer used in the above method include vinylsilane represented by the following formula (I) and (meth) acrylamide-alkylsilane represented by the following formula (II).

[0013]

[Chemical 1]

[Wherein n is an integer of 0 to 4, m is an integer of 0 to 2, R ¹ is an alkyl group having 1 to 5 carbon atoms (methyl, ethyl, etc.), and R ² is an alkoxyl having 1 to 40 carbon atoms. A group or an acyloxyl group (the alkoxyl group and the acyloxyl group may have a substituent containing oxygen), R ³ is a hydrogen atom or a methyl group, R ⁴ is a hydrogen atom or a carbon number of 1 to 5 Alkyl group, R ⁵ has 1 to ⁵ carbon atoms
Represents a divalent organic residue in which chain carbon atoms are linked to each other by oxygen or nitrogen. When R ¹ has two or more in the same monomer, each R ¹ may be the same or different. Also, when R ² has two or more in the same monomer, each R ² may be the same or different. Specific examples of the vinylsilane represented by the formula (I) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris- (β-methoxyethoxy) silane, vinyltriacetoxysilane, allyltrimethoxysilane, and allyltriacetoxysilane. , Vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, vinyldimethylacetoxysilane, vinylisobutyldimethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyl Trihexyloxysilane, vinylmethoxydihexyloxysilane, vinyltrioctyloxysilane, vinyldimethoxyoctyloxysilane, vinylmethoxydioctyl Kishishiran, vinyl methoxy dilaurate Lilo silane, vinyl dimethoxy Lau Lilo silane, vinyl methoxy geo Ray B silanes, vinyl dimethoxy I acetoxyphenyl silane, more general formula

[0015]

[Chemical 2]

[Wherein R ¹ and m are the same as above, x is 1 to
Indicates an integer of 20. ] Polyethylene glycolated vinyl silane and the like represented by Further, specific examples of the (meth) acrylamide-alkylsilane represented by the formula (II) include 3- (meth) acrylamide-propyltrimethoxysilane and 3- (meth) acrylamide-
Propyltriethoxysilane, 3- (meth) acrylamide-propyltri (β-methoxyethoxy) silane,
2- (meth) acrylamido-2-methylpropyltrimethoxysilane, 2- (meth) acrylamido-2-methylethyltrimethoxysilane, N- (2- (meth) acrylamido-ethyl) -aminopropyltrimethoxysilane, 3 -(Meth) acrylamide-propyltriacetoxysilane, 2- (meth) acrylamide-ethyltrimethoxysilane, 1- (meth) acrylamide-methyltrimethoxysilane, 3- (meth) acrylamide-propylmethyldimethoxysilane, 3- ( (Meth) acrylamido-propyldimethylmethoxysilane, 3-
(N-methyl- (meth) acrylamide) propyltrimethoxysilane, 3-((meth) acrylamide-methoxy) -3-hydroxypropyltrimethoxysilane, 3-((meth) acrylamide-methoxy) -propyltrimethoxysilane; N, N-Dimethyl-N-trimethoxysilylpropyl-3- (meth) acrylamido-propylammonium chloride; N, N-Dimethyl-N-trimethoxysilylpropyl-2- (meth) acrylamido-2-methylpropylammonium chloride Etc.

In carrying out the copolymerization of the vinyl ester and the silyl group-containing olefinically unsaturated monomer by the above-mentioned method, other unsaturated monomer copolymerizable with the monomer other than the above two components is used. Polymers such as styrene, alkyl vinyl ether, vinyl versatate, (meth) acrylamide, or olefins such as ethylene, propylene, α-hexene, α-octene, (meth) acrylic acid, crotonic acid, (anhydrous) maleic acid, fumaric acid Unsaturated acids such as acid and itaconic acid and their alkyl esters and alkali (earth) metal salts, sulfonic acid-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid and alkali (earth) metal salts thereof, Trimethyl-3- (1- (meth) acrylamide-1,1-dimethylpropyl) ammonium chloride, tri It is also possible to allow a small amount of a cationic monomer such as methyl-3- (1- (meth) acrylamidopropyl) ammonium chloride, 1-vinyl-2-methylimidazole and a quaternary compound thereof to be present.

Further, in the above method, that is, in the method of saponifying a polyvinyl ester having a silyl group at the terminal, which is obtained by polymerizing a vinyl ester in the presence of a mercaptan having a silyl group, the following operation is carried out. .. For example, when polymerizing a vinyl ester using a radical initiator, a mercaptan having a silyl group is added to the polymerization system all at once or separately or continuously,
A mercaptan having a silyl group is allowed to exist in the polymerization system, and a polyvinyl ester having a silyl group at the terminal is produced by chain transfer to the mercaptan, and then an alkali or acid catalyst is added to an alcohol solution of the polyvinyl ester to give the polyvinyl ester. By saponifying the ester, a modified PVA having a desired silyl group can be obtained. Examples of the silyl group-containing mercaptan used in this method include 3- (trimethoxysilyl) -propyl mercaptan and 3- (triethoxysilyl) -propyl mercaptan. When the modified PVA having a silyl group is produced by this method, it is possible to allow a small amount of an unsaturated monomer copolymerizable with the vinyl ester used in the above method to be present.

As described above, the modified P containing a silyl group in the molecule
Although the method for producing VA has been described in detail, of these, the method by copolymerization (that is, the method) is more preferable than the method by post-modification in terms of easiness of industrial production. Further, in the method for producing a modified PVA by copolymerization, the saponified copolymer of the silyl group-containing olefinically unsaturated monomer represented by the formula (I) and the vinyl ester, which is produced according to the method, It is preferably used because it is excellent in the viscosity stability of the aqueous solution, the stability to alkali when made into an alkaline aqueous solution, and the water resistance when formed into a film. Above 3 methods (method ~)
Denatured degree of modified PVA obtained by
The silyl group content in A is 0.01 to 5 mol% as a monomer unit containing a silyl group in the molecule, preferably 0.1 to
The amount is 1.0 mol%, more preferably 0.1 to 0.6 mol%.

When the silyl group content in the modified PVA is less than 0.01 mol%, the effect of reinforcing the surface layer of the inorganic plate is not obtained,
On the other hand, when it exceeds 5 mol%, the stability of the aqueous emulsion which is the component (B) used together becomes poor, and the water-stopping property or the adhesion to the finishing treatment material is deteriorated, which is not preferable. In order to cause pseudo-aggregation of an aqueous emulsion such as an acrylic emulsion as described below, it is preferable that
0.1-1.0 mol%, more preferably 0.1-0.6 mol%
Is. The degree of polymerization of the modified PVA (both post-modified PVA and modified PVA by copolymerization) is not particularly limited and may be appropriately determined according to various situations, but is usually 100-
3000, preferably 300 to 2000. The degree of saponification is also not particularly limited, but generally 70-
It is selected from the range of 100 mol%. The silyl group-containing modified PVA thus obtained is dispersed in water, and if necessary, a small amount of alkali such as sodium hydroxide, potassium hydroxide, ammonium hydroxide or amine is added, and the mixture is moistened with stirring. A uniform aqueous solution can be obtained.

On the other hand, the component (B) in the composition of the present invention
The aqueous emulsion having a glass transition temperature of 5 to 100
There is no particular limitation as long as it is an aqueous emulsion containing a water-insoluble polymer having a temperature of ℃ and an average particle diameter of 0.2 μm or more as a dispersoid. The glass transition temperature (hereinafter abbreviated as Tg) of the water-insoluble polymer in the aqueous emulsion is 5 to 100 ° C.
It is necessary to be, and preferably 10 to 60 ° C. Average particle size of dispersoid in aqueous emulsion is 0.2 μm
It is necessary to be above, and preferably 0.3 to 2μ.
m, more preferably 0.4 to 1.5 μm, even more preferably
It is 0.4 to 0.9 μm. When the Tg of the emulsion is less than 5 ° C, the surface layer reinforcing effect is low and the blocking property is poor.
On the other hand, when the Tg is higher than 100 ° C., it is not preferable because the high temperature drying of the ordinary inorganic plate coating line results in poor film formation. The average particle size of the aqueous emulsion is 0.2μ.
If it is less than m, the adhesion to the finishing material is reduced.

The constituent units of the water-insoluble polymer, which is the dispersoid of the aqueous emulsion, include acrylic acid esters such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, and decyl acrylate; methacrylic acid. Methacrylic acid esters such as ethyl acetate, butyl methacrylate, hexyl methacrylate, decyl methacrylate, lauryl methacrylate, stearyl methacrylate; vinyl acetate, vinyl propionate, vinyl pivalate, vinyl having an alkyl group with 8 to 10 carbon atoms. Ester (for example, Shell Chemical Co., Ltd., trade name: Veo
Va10), vinyl esters such as vinyl stearate;
Maleic acid esters such as diethyl maleate, dibutyl maleate and dioctyl maleate; Fumarate esters such as dibutyl fumarate and dioctyl fumarate; dimethyl itaconate, dibutyl itaconate and di2 itaconic acid
-Structural units derived from itaconic acid esters such as ethyl hexyl and the like. The number of units derived from these ethylenically unsaturated monomers may be one, or 2
It may be a combination of two or more species.

Among the above water-insoluble polymers, in particular, vinyl acetate units and ethylene, acrylic acid esters, methacrylic acid esters copolymerizable with vinyl acetate units,
A copolymer with a unit derived from at least one ethylenically unsaturated monomer selected from vinyl ester, maleic acid ester, fumaric acid ester and itaconic acid ester is preferable. The content of each constitutional unit in this copolymer is not particularly limited, but the content of vinyl acetate units relative to the entire copolymer is preferably 1 to 90% by weight,
80% by weight is more preferred. The content of the ethylenically unsaturated monomer unit is preferably 10 to 99% by weight, and 20 to 90% by weight.
Weight percent is particularly preferred. When the content of the ethylenically unsaturated monomer unit is too small, the water resistance of the obtained film becomes insufficient, the adhesion to the finishing material is insufficient due to water absorption or moisture absorption, and the calcium silicate etc. When applied to a strongly alkaline inorganic plate, hydrolysis of the water-insoluble polymer may occur easily.

Among the aqueous emulsions (B) in the composition of the present invention, the aqueous emulsion using PVA as a dispersant is preferable. PVA used as a dispersant
Is, for example, a saponification degree of 80 to 99 mol% and a polymerization degree of 200.
In addition to PVA of up to 8000, so-called modified PVA having a functional group introduced in the main chain, side chain or molecular end is also suitable.
In addition, as long as the performance of the aqueous emulsion is not impaired, P
An emulsion stabilizer other than VA can be used in combination with PVA. Aqueous emulsion (B) in the composition of the present invention
Can be manufactured in various ways. For example, PV
It is obtained by emulsion-copolymerizing vinyl acetate and an ethylenically unsaturated monomer copolymerizable therewith in the presence of A by a known method. The initiator in this emulsion polymerization is not particularly limited, but for example, hydrogen peroxide, cumene hydroperoxide, t-butyl hydroperoxide, persulfate (potassium, sodium or ammonium salt), peracetic acid t- Oxidizing substances such as butyl and t-butyl perbenzoate, and water-soluble initiators such as reducing substances such as Rongalit and 1-ascorbic acid are preferably used.

If desired, various aqueous emulsions (average particle size of dispersoids of less than 0.2 μm) can be added to the aqueous emulsion (B) of the present invention. As such an aqueous emulsion, a polyvinyl acetate emulsion,
Ethylene-vinyl acetate copolymer emulsion, polychloroprene emulsion, polybutadiene emulsion,
Examples thereof include styrene-butadiene copolymer emulsion, butadiene-acrylonitrile copolymer emulsion, butyl rubber emulsion, polyacrylic ester emulsion, polyvinyl chloride emulsion, polyvinylidene chloride emulsion and the like.

The composition of the present invention basically comprises the component (A).
And the component (B) as a main component, the water-proofing agent (C) of the component (A) can be blended if necessary. Here, as the water resistant agent which is the component (C),
Colloidal silica, water glass, borax, water-dispersible isocyanate compound, polyamide resin, melamine resin, polyamide methylol resin, polyethylene imide, etc. are used, and among them, colloidal silica or water-dispersible isocyanate compound is preferable. Here, as the water-dispersible isocyanate compound, a water-emulsifiable methylenebisdiphenyl isocyanate (water-emulsifiable MDI) (for example, Nippon Polyurethane Co., Ltd., trade name: Coronate C-3053) is used.
Or a water-emulsifiable blocked urethane prepolymer (for example, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Elastron E
-37) and other self-emulsifying isocyanate compounds. In addition, tolylene diisocyanate (TD
I); hydrogenated TDI; trimethylolpropane-TDI
Adduct (eg Bayer, trade name: Desmo
dur L); triphenylmethane triisocyanate; methylenebisdiphenyl isocyanate (MD
I); hydrogenated MDI; polymerized MDI; hexamethylene diisocyanate; xylylene diisocyanate; 4,4-
Dicyclohexylmethane diisocyanate; those obtained by forcibly emulsifying isophorone diisocyanate and the like in the presence of an appropriate emulsifier are mentioned.

As described above, the composition of the present invention contains the component (A) and the component (B) as main components, and the solid content weight ratio (A) / (B) of both is 5/95. ~ 50 /
It must be in the range of 50, preferably 7/9
It is in the range of 3 to 40/60. When the water content of the inorganic plate to be coated is 20% by weight or more, the composition of the present invention is
It is preferable to use the component (C) as the main component together with the components (A) and (B). In that case, the solid content weight ratio of each component is (A) / (B) 5/95 to 50/50. , (A) /
(C) is preferably in the range of 99.5 / 0.5 to 10/90, and particularly (A) / (B) is 7/93 to 40/6.
The optimum range of 0, (A) / (C) is 99/1 to 50/50. In the case of a high density porous inorganic plate, the component (C) is preferably a water dispersible isocyanate compound, and (A) / (B) is 5/95 to 50/50,
The range of (A) / (C) is preferably 99/1 to 50/50.

Further, the composition of the present invention contains the component (A), the component (B) and, if necessary, the component (C) as the main components as described above, but the mixing method of each of these components is not particularly limited. There is no. As a compounding method, for example, an aqueous emulsion of the silyl group-containing modified PVA, which is the component (A), is mixed into an aqueous emulsion that is the component (B) while stirring, and if desired, a water-proofing agent that is the component (C). Is preferably mixed at the end, and the component (C) is preferably mixed immediately before being applied as a sealer to the inorganic plate. In the composition of the present invention, in addition to the above components, inorganic pigments such as calcium carbonate, clay, titanium oxide, zinc oxide, red iron oxide, etc., urea as a stabilizer for coating liquid, defoaming agent, etc. are dispersed and mixed. You may. Further, it may be diluted with water at the end so as to obtain a coating solution having an appropriate viscosity. The coating liquid concentration is usually 10
-60% (solid content concentration), preferably 20-40% (solid content concentration).

The composition of the present invention is used for various purposes, and is particularly suitable as a sealer for porous inorganic plates.
When the composition of the present invention is used as a sealer, examples of the porous inorganic plate to be applied include those containing an inorganic material such as a cement-based, calcium silicate-based, gypsum-based, sand, or clay mineral-based material as a main component. Specific examples thereof include lightweight concrete, precast concrete, lightweight cellular concrete (ALC), mortar, asbestos cement board, calcium silicate board, pulp cement board, wood wool cement board, gypsum board, hard board and the like. These inorganic plates may contain an organic component, but the composition of the present invention is particularly suitable for a porous inorganic plate mainly composed of a compound such as Si, Ca, Mg or Al. Is suitable. As a coating method for the inorganic plate, any general coating method such as spray coating, roller coating, flow coater, and dipping can be used. Coating amount as dry solids
It is preferably 0.5 to 100 g / m ² . It is more effective to heat-dry at 100 ° C. or higher after applying the composition of the present invention.

The composition of the present invention is water-based, but it is hard to cause coating defects, has a surface layer reinforcing effect comparable to a solvent-based sealer in a single coating, water-stopping performance, wet water resistance and hot water resistance, and It is extremely useful as an industrial material that can obtain excellent adhesion to a finishing material even after being left for a long time after the sealer treatment.

The reason why the composition of the present invention exerts extremely excellent performance as described above is not clear, but
It is estimated as follows. That is, by observing the composition of the present invention with a microscope, a phenomenon peculiar to the mixed state of the main component, that is, the modified PVA having a silyl group in the molecule (component (A)) and the aqueous emulsion (component (B)) is recognized. Was given. It is not that the individual particles of the aqueous emulsion are uniformly dispersed as islands in the sea of the aqueous solution of the silyl group-containing modified PVA, but are several tens to several hundred times the size of the original particles. It was found that pseudo aggregation occurred. The term "pseudo-aggregation" as used herein means that, when diluted with water, the aggregated state forms a particle group having a light structure that is dispersed to the order of the original primary particles.

Because of such a mixed state, when the composition of the present invention is applied to a porous inorganic plate, a silyl group-containing modification, which is one of the components, is mainly present inside the inorganic plate as compared with the case of a uniform mixed state. PVA is easily permeated, and the other component, the aqueous emulsion, forms a group of particles that are much larger than the pores on the surface of the inorganic plate, so it has little permeation and forms a film with a composition rich in aqueous emulsion on the surface layer. it is conceivable that. Moreover, the composition of both the silyl group-containing modified PVA and the aqueous emulsion in the direction of coating thickness is
It is considered that since the film on the surface layer does not easily peel off from the inorganic plate because of the continuous change, the water blocking performance is exhibited. That is, the silyl group-containing modified PVA interacts with compounds such as Si, Ca, Mg, and Al, which are components of the inorganic plate, to an extent unmatched with conventional PVA, and therefore has permeability to the inorganic plate. It is considered that the surface layer reinforcing effect can be remarkably improved as a result.
Further, when the average particle size of the dispersoid of the aqueous emulsion of the component (B) is 0.2 μm or more, good pseudo-aggregation is generated as compared with the conventional aqueous emulsion having a small particle size, and as a result, the inorganic substance is It is presumed that the yield on the surface of the plate is improved and the adhesion between the inorganic plate and the topcoat finishing material is improved.

The silyl group-containing modified PVA of the composition of the present invention permeates into the large holes on the surface of the inorganic plate together with a part of the emulsion. This modified PVA interacts with the components of the inorganic plate. Since it has a strong action, it forms a gel film with excellent water resistance at an appropriate depth from the surface layer of the inorganic plate, so the coating liquid does not excessively penetrate, and thus coating defects are less likely to occur, resulting in better stopping. It is considered that the aqueous solution was obtained. It is considered that the appropriate permeability to the inorganic plate is due to the degree of pseudo-aggregation obtained by the mixing ratio of the silyl group-containing modified PVA and the aqueous emulsion and the average particle diameter of the aqueous emulsion. Further, in the present invention, a water resistant agent can be added as a component (C), if necessary. The water resistant agent renders the silyl group-modified PVA water resistant, and a water dispersible isocyanate compound is used as the water resistant agent. When used, it is considered that both the silyl group-modified PVA and the aqueous emulsion are made water resistant, and as a result, the hot water resistance and hot water resistance of the sealer coating film are further significantly improved.

[0034]

EXAMPLES The present invention will be specifically described below with reference to examples, but these examples do not limit the present invention. All parts or percentages are by weight unless otherwise specified. The test methods used in the examples are as follows.

(1) Water Permeability Test In a test for measuring the water stopping performance of a sealer, the composition of the present invention was applied to various porous inorganic plates at a solid content of 20 g / m ^2.
Apply and dry at 150 ℃ for 20 minutes, then at 20 ℃, 65% R
It was left for 7 days under H (relative humidity) conditions. On the surface of this test piece, fix the open end of the triangular funnel with an epoxy adhesive so as not to leak water, connect a buret to the tip of the test piece, add water so that the initial head is 25 cm, and reduce the amount of water decrease after 8 hours. Read The smaller the value, the better the waterproof performance.

(2) Adhesion test A test for measuring the effect of reinforcing the surface layer of the porous inorganic plate by the sealer and the adhesion between the surface layer of the inorganic plate and the finishing treatment agent. The sealer is applied by the method of (1). Solvent-based acrylic resin paint (Toa Paint Co., Ltd., Acrylic D for toa tile)
(X, white) was applied, and while the solvent-type acrylic resin paint was not dried, a cotton cloth was placed on it and dried at room temperature for 2 days. Then, a cut was made in a 1 cm width with a knife, and the peeling resistance was measured with an autograph (Shimadzu Corporation, IM-100 type) at a peeling angle of 90 ° and a pulling speed of 50 mm / min, and the peeling state was observed. That is, those having poor adhesion to the top coat are peeled off at the interface between the sealer-coated surface and the top coat. Further, those having a large reinforcing effect on the surface layer of the inorganic plate have large peeling resistance, and many fractured parts of the inorganic plate adhere to the peeling surface.

(3) Weathering test Inorganic plates such as building materials may be left for several months or more after the sealer treatment and before the cosmetic finish. In this case, the sealer-treated plate used for construction is exposed to sunlight, rain, and wind. If the sealer-treated surface is roughened or discolored by such exposure, the cosmetic finish will be impaired. Also, the adhesiveness with the decorative finish changes. The weathering test is a test for measuring the weather resistance due to such outdoor exposure, and the sample treated with the sealer by the method (1) is
Xenon lamp (XW-60 manufactured by Shimadzu Corporation) under 40 ° C
(V ₃ , 6 kW) irradiation for 200 hours and water spraying for 18 minutes every 2 hours were performed, and the change of the sealer treated surface was examined. Further, the sample after irradiation was coated with a topcoat paint to examine the adhesion.

(4) Marlon Mechanical Stability Test This is a test for measuring the stability of the liquid at the time of coating the sealer, and is a Marlon tester (manufactured by Shinsei Sangyo Co., Ltd., MARO).
N, 1000 rpm) and load 25k on 50 g coating liquid
A shearing force was applied at 1000 rpm for 10 minutes, and the amount of gelled product generated (expressed in% by weight based on the solid content of 50 g of coating liquid after separating and drying the gelled product with a 100 mesh wire net).
I checked.

(5) Hot water resistance test The composition of the present invention was added to a porous inorganic plate at a solid content of 20 g / m 2.
^After coating and drying at 150 ° C. for 20 minutes, a solvent-type acrylic resin coating (Toa Paint Co., Ltd., acrylic DX for toilet, white) was coated and dried at room temperature for 2 days. This coated product was continuously immersed in warm water at 50 ° C. for 2 weeks, and swelling of the top coating composition was observed.

(6) Hot water resistance test The composition of the present invention was applied to a porous inorganic plate at a solid content of 20 g / m 2.
^After coating and drying at 150 ° C. for 20 minutes, a solvent-type acrylic resin coating (Toa Paint Co., Ltd., acrylic DX for toilet, white) was coated and dried at room temperature for 2 days. This coating was immersed in hot water at 80 ° C. for 2 hours, and the swelling of the top coating was observed.

Example 1 A copolymer of vinyltrimethoxysilane and vinyl acetate was saponified to contain a silyl group as a vinylsilane unit in an amount of 0.5 mol%, and the saponification degree of the vinyl acetate unit was 98.5 mol%.
Modified PVA having a degree of polymerization of 500 and containing a silyl group in the molecule
Got This modified PVA was dissolved in water to prepare a 15% aqueous solution. On the other hand, 220 g of water and 20 g of unmodified PVA (polymerization degree 550, saponification degree 88.2 mol%) were added to a 1-liter four-necked flask equipped with a reflux condenser, and the unmodified PVA was dissolved at 95 ° C. to room temperature. Cooled down. Next, using 0.4 g of hydrogen peroxide and 2 g of Rongalit as an initiator, 100 g of vinyl acetate monomer (VAc), 50 g of methyl methacrylate (MMA) and n-butyl acrylate (n-
A mixture of 50 g of BA) was continuously added over 3 hours, and emulsion copolymerization was performed at 70 ° C. to obtain an aqueous emulsion (I) having a concentration of 50%. Tg of this aqueous emulsion is 1
The average particle diameter was 4 ° C. and 0.6 μm. To 100 parts of this aqueous emulsion (I), 85 parts of a 15% aqueous solution of the modified PVA prepared above was mixed with stirring, correction water was added, and a sealer composition having a concentration of 25% (modified PVA and aqueous emulsion (I) was added. Solid content mixing ratio: 20/80) was obtained. This composition was added to a calcium silicate plate (specific gravity 0.8).
5, water content 7%) to evaluate the performance. The results are shown in Table-1. The Tg of the aqueous emulsion is 90% of the modified PVA in the film obtained by forming the composition into a film.
It was extracted with hot water at 0 ° C., the water-insoluble polymer that was not extracted from the hot water was vacuum dried, and then measured using a differential scanning calorimeter (DSC). The average particle size was determined by taking an electron micrograph using a transmission electron microscope and calculating the number average particle size.

Comparative Example 1 The procedure of Example 1 was repeated, except that the modified PVA aqueous solution was used instead of the sealer composition of Example 1. The results are shown in Table-1.

Comparative Example 2 The procedure of Example 1 was repeated, except that the sealer composition of Example 1 was replaced with a solution prepared by adjusting the concentration of the aqueous emulsion (I) to 25%. The results are shown in Table-1.

Comparative Example 3 Instead of the modified PVA of Example 1, PVA-105
(Manufactured by Kuraray Co., Ltd., PVA, degree of polymerization 550, degree of saponification 9
The same procedure as in Example 1 was performed except that 8.5 mol%) was used. The results are shown in Table-1.

Comparative Example 4 The same procedure as in Example 1 was carried out except that the existing solvent type urethane sealer (manufactured by Toa Paint Co., Ltd., Asbestos Sealer # 20) was used in place of the sealer composition of Example 1. It was The results are shown in Table-1.

Comparative Example 5 Calcium silicate plate (specific gravity 0.85, water content 7%)
The performance was evaluated without applying the sealer composition. The results are shown in Table-1.

[0047]

[Table 1]

As shown in Table 1, the composition of the present invention has no coating defects, and is excellent in waterproof performance, surface layer reinforcing effect, and adhesion to the top coating (direct application and application after weathering).

Examples 2 to 4 In Example 1, vinyl acetate monomer (VAc) 10
0 g, 50 g of methyl methacrylate (MMA) and 50 g of n-butyl acrylate (n-BA), instead of Table-
Aqueous emulsions (II) to (IV) were obtained in the same manner as in Example 1 except that the monomer having the composition shown in 2 was used. Tg of these emulsions is 5 to 100
C., and the average particle size was 0.2 μm or more.
Next, a sealer composition was obtained in the same manner as in Example 1 except that the aqueous emulsions (II) to (IV) were used instead of the aqueous emulsion (I). I went. The results are shown in Table-3.

Example 5 A 1-liter four-necked flask equipped with a reflux condenser was charged with 220 parts of water.
g and unmodified PVA (polymerization degree 550, saponification degree 88.2
Mol%) 16 g and added at 95 ° C. to the unmodified PVA
Was dissolved and cooled to room temperature. Next, 100 g of vinyl acetate monomer (VAc) was added, and emulsion polymerization was carried out at 60 ° C. with a conversion rate of 95% by using 0.05 g of potassium persulfate as an initiator. Then, methyl methacrylate (MMA)
A mixture of 50 g and 50 g of n-butyl acrylate (n-BA) was added over 2 hours, and vinyl acetate (core) and (methyl methacrylate-n-butyl acrylate (shell)) were added by two-step polymerization. A core / shell type emulsion (V) consisting of Tg of emulsion (V) is 1
The average particle diameter was 5 ° C. and 0.7 μm. A sealer composition was obtained in the same manner as in Example 1 except that the above emulsion (V) was used in place of the emulsion (I), and the same performance evaluation as in Example 1 was performed. .. The results are shown in Table-3.

Example 6 Same as Example 1 except that 10 g of non-modified PVA and 5 g of Nonipol S-40 (manufactured by Sanyo Kasei Co., Ltd.) were used in combination in place of 20 g of non-modified PVA as a stabilizer. To obtain an aqueous emulsion (VI). This emulsion (VI) had a Tg of 13 ° C and an average particle size of 0.3.
was μm. In Example 1, emulsion (I)
Except that the above emulsion (VI) was used instead of
A sealer composition was obtained in the same manner as in Example 1, and the same performance evaluation as in Example 1 was performed. The results are shown in Table-3.

Comparative Example 6 Vinyl acetate monomer 100 g, methyl methacrylate 30
g and n-butyl acrylate 70 g were used as monomers to obtain an aqueous emulsion (VII) in the same manner as in Example 1. The Tg of this emulsion (VII) is -5.
C., and the average particle size was 0.5 μm. A sealer composition was obtained in the same manner as in Example 1 except that the above emulsion (VII) was used in place of the emulsion (I), and the same performance evaluation as in Example 1 was performed. .. The results are shown in Table-3.

Comparative Example 7 In Example 1, 10 g of Nonipol S-40 (manufactured by Sanyo Kasei Co., Ltd.) was used as the stabilizer in place of 20 g of unmodified PVA.
An aqueous emulsion (VIII) was obtained in the same manner as in Example 1 except that the monomers used were those having the composition shown in Table 2. Tg of this emulsion (VIII)
Was 12 ° C. and the average particle size was 0.15 μm. A sealer composition was obtained in the same manner as in Example 1 except that the above emulsion (VIII) was used in place of the emulsion (I), and the same performance evaluation as in Example 1 was performed on this. .. The results are shown in Table-3.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

Examples 7-9 and Comparative Examples 8 and 9 Modified PVA and aqueous emulsion (I) of Example 1
A sealer composition was obtained in the same manner as in Example 1 except that the compounding ratio with was changed as shown in Table 4, and the same performance evaluation as in Example 1 was performed for this. The results are shown together in Table-4.

[0058]

[Table 5]

Example 10 A copolymer of vinyltriacetoxysilane and vinyl acetate was saponified to give a silyl group as a vinylsilane unit of 0.2.
A modified PVA having a vinyl acetate unit content of 98.5 mol% and a polymerization degree of 1000 containing a silyl group was obtained. This modified PVA was dissolved in water to obtain a 15% aqueous solution (see Table-5). A sealer composition was obtained in the same manner as in Example 1 except that this modified PVA aqueous solution was used, and the same performance evaluation as in Example 1 was performed for this.
The results are shown together in Table-6.

Examples 11 to 14 and Comparative Examples 10 and 11 The same operation as in Example 10 was carried out except that the modified PVA used in Example 10 was replaced with the modified PVA shown in Table 5. .. The results are shown together in Table-6.

[0061]

[Table 6]

[0062]

[Table 7]

[0063]

[Table 8]

Example 15 100 parts of the sealer composition of Example 1 was mixed with colloidal silica (manufactured by Catalysts & Chemicals Industry Co., Ltd., S1-50) as a waterproofing agent.
35 parts (0) (prepared to a solid content of 20% and used) were added to obtain a composition, and the same performance evaluation as in Example 1 was performed. The results are shown in Table-7.

Example 16 The same operation as in Example 15 was carried out except that a polyamide resin (Sumitomo Chemical Co., Ltd., Sumireze EX70M) was used as the waterproofing agent. The results are shown in Table-7.

Example 17 In Example 15, a polyamide methylol resin (Sumitomo 633, manufactured by Sumitomo Chemical Co., Ltd.) was used as a waterproofing agent.
The same operation as in Example 15 was performed except that was used. The results are shown in Table-7.

Example 18 The same operation as in Example 15 was carried out except that polyethyleneimine (Epomin SP1000, manufactured by Nippon Shokubai Kagaku Co., Ltd.) was used as the waterproofing agent. The results are shown in Table-7.

Example 19 A hot water resistance test was conducted on the calcium silicate plate coated with the sealer composition of Example 1. The results are shown in Table-7.

[0069]

[Table 9]

Examples 20 to 23 The composition ratios of the modified PVA and colloidal silica in Example 15 were changed as shown in Table-8, and the water content of the calcium silicate plate at the time of coating the composition was shown in Table-8. The same operation as in Example 15 was performed except that the change was made as shown in 8. The results are shown together in Table-8.

[0071]

[Table 10]

[0072]

[Table 11]

Example 24 To 100 parts of the sealer composition of Example 1 (concentration 25%),
Water-emulsifiable MDI as water-dispersible isocyanate compound
(Nippon Polyurethane Co., Ltd., Coronate C-305
3) Add 10 parts to obtain the composition of which Example 1
The same performance evaluation as was performed. The results are shown in Table-9.

Example 25 As Example 24, except that a water-emulsifiable blocked urethane prepolymer (Elastron E-37 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used as the water-dispersible isocyanate compound. The same operation was performed. The results are shown in Table-9.

Examples 26 to 28 The solid content ratios of the sealer composition and the water-emulsifiable MDI in Example 24 were changed as shown in Table-9, and the calcium silicate plate was absolutely dried at the time of coating the composition. The same operation as in Example 24 was performed except that the ratio was changed as shown in Table-9.
The results are shown together in Table-9.

[0076]

[Table 12]

[0077]

[Table 13]

[0078]

Industrial Applicability As described above, the composition of the present invention is used for various purposes, but is particularly suitable as a sealer for porous inorganic plates. The composition of the present invention is a water-based composition and is unlikely to cause coating defects, and has a surface-layer reinforcing effect, water-stopping performance, moisture resistance and hot-water resistance comparable to a solvent-based sealer even in the case of a single coating, and a sealer. It is extremely useful as an industrial material that can obtain excellent adhesion to a finishing material even after being left for a long time after the treatment.
Further, the composition of the present invention can be used as an inorganic binder, a coating agent for an inorganic plate, and an antifogging agent in addition to the use as the sealer of the porous inorganic plate.

Claims (3)

[Claims] 1. A modified polyvinyl alcohol (A) containing 0.01 to 5 mol% of a silyl group in the molecule and a water-insoluble polymer having a glass transition temperature of 5 to 100 ° C. and an average particle diameter of 0.2 μm or more are dispersed. Quality water-based emulsion (B), solid content ratio (A) / weight basis
(B) is 5 / 95-50 / 50, The composition characterized by the above-mentioned. 2. The composition according to claim 1, which contains the water-proofing agent (C) as the component (A). 3. A sealer composition for a porous inorganic plate, which comprises the composition according to claim 1 or 2.