JPH06184463A - Composition - Google Patents

Abstract

PURPOSE:To obtain a composition effectively usable as various industrial materials including sealers, etc., by precoating the surface of an inorganic board so as to enable the effective practice of surface decorative finish of the porous inorganic board. CONSTITUTION:This composition is composed of (A) a modified polyvinyl alcohol containing 0.01-5mol% silyl group in the molecule and (B) an aqueous emulsion containing a dispersed phase which is a (co)polymer composed of an acrylic acid ester-based, a methacrylic acid ester-based, a styrenic or a diene-based monomer and a dispersing agent that is a polyvinyl alcoholic polymer having mercapto group in the terminal at (5/95) to (50/50) solid blending ratio of the components (A) to (B) based on weight.

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 and the like. 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 have low surface layer 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 building 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 required properties for such a sealer are roughly classified into three, that is, the effect of reinforcing the surface layer of the inorganic plate, the waterproof performance, and the adhesiveness with 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, a water-based sealer containing an acrylic emulsion using a low-molecular-weight surfactant as a dispersant is known. Although this has the advantage of not using a solvent at all, since the surface layer reinforcing effect of the inorganic plate is extremely small, there is no problem for a while when finishing, but peeling may occur at the surface layer of the inorganic plate after several months. There is a problem that it cannot be used stably. Also regarding the water stop performance,
Although it is a hydrophobic resin by nature, it is difficult to obtain a sufficiently satisfactory one. The reason for this is that the thickener used together decreases the water resistance of the coating film, and defects during coating are more likely to occur than with 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), and solid on a weight basis. 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
A 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 higher performance sealers are required in terms of the effect of reinforcing the surface layer and the adhesion to the water-stop finishing material.

[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 It is an object of the present invention 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. 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. It is an object of the present invention to provide a composition that can be applied to a difficult high density porous inorganic plate.

The present inventors have conducted extensive studies to overcome the various drawbacks of the prior art and achieve the above object. As a result, the modified polyvinyl alcohol containing a silyl group in the molecule and the dispersoids of acrylic acid ester type and methacrylic acid ester type (hereinafter, acrylic acid ester and methacrylic acid ester are referred to as “(meth) acrylic acid ester”). , A homopolymer or copolymer composed of one or more monomers selected from styrene-based and diene-based monomers (hereinafter referred to as “(co)”).
Sometimes referred to as a polymer. ), And a composition having an aqueous emulsion whose main component is a polyvinyl alcohol-based polymer having a mercapto group as a dispersant, and
It has been found that a composition to which a water-proofing agent is added has physical properties suitable for the above purpose. The present invention has been completed based on such findings.

That is, the present invention has a silyl group in the molecule.
The modified polyvinyl alcohol (A) having 0.01 to 5 mol% and one or more of the dispersoids selected from (meth) acrylic acid ester-based monomer units, styrene-based monomer units and diene-based monomer units. Including monomer unit (co)
The polymer is an aqueous emulsion (B) in which the dispersant is a polyvinyl alcohol polymer having a mercapto group at the terminal, and the solid content ratio (A) /
(B) is 5/95 to 50/50, and a composition comprising the water-proofing agent (C) of the above-mentioned component (A) added thereto. Is also provided.

The modified polyvinyl alcohol (modified PVA) which is the component (A) of the composition of the present invention may be any as long as it contains a silyl group in the molecule, but the silyl group contained in the molecule is an alkoxyl group. Those 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 are 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 that does not react with the silylating agent (benzene, toluene, xylene, hexane, heptane, ether, acetone, etc.), and the resulting solution is added. By suspending powdered PVA or the above modified polyvinyl acetate with stirring and reacting the silylating agent with PVA or the above modified polyvinyl acetate at room temperature to a temperature in the boiling point range of the silylating agent, or by further adding an alkali A silyl group-containing modified PVA can be obtained by saponifying a vinyl acetate unit with a catalyst or the like.

As the silylating agent used in the post-modification, organohalogenosilane 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, trimethylsilyl isocyanate, 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, 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. Copolymerization with a monomer using a radical initiator, then adding an alkali or acid catalyst to the alcohol solution of the resulting copolymer, and saponifying the copolymer to give the desired silyl group-containing content. 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).

[0014]

[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 C 1-5 group. 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 two or more R ² are contained 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

[0016]

[Chemical 2]

[Where 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 olefinic unsaturated monomer by the above method, another 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 Acids, unsaturated acids such as itaconic acid and their alkyl esters and alkali (earth) metal salts, sulfonic acid-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid and their alkali (earth) metal salts, 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 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%, there is no effect of reinforcing the surface layer of the inorganic plate,
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
In the aqueous emulsion, the dispersoid is a (co) polymer composed of at least one monomer selected from (meth) acrylic acid ester-based, styrene-based and diene-based (that is, one of these monomer units is (Including) (co) polymer
It is necessary that the dispersant is an aqueous emulsion which is a polyvinyl alcohol polymer having a mercapto group at the terminal. Examples of the (meth) acrylic acid ester-based monomer in the aqueous emulsion of the present invention include methyl (meth) acrylate, ethyl (meth) acrylate,
Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, (meth)
2-hydroxyethyl acrylate, dimethylaminoethyl (meth) acrylate and quaternary products thereof, glycidyl methacrylate and the like can be mentioned.

Examples of styrene-based monomers include styrene and α
-Methyl styrene, p-methyl styrene sulfonic acid and sodium, potassium salt, etc. are mentioned, and also as a diene type monomer, butadiene, isoprene, chloroprene are mentioned. Further, the aqueous emulsion in the present invention can copolymerize monomers other than the (meth) acrylic acid ester-based, styrene-based, and diene-based monomers as long as the performance is not impaired. As the copolymerizable monomer,
Olefins such as ethylene, propylene and isobutylene,
Vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, etc., halogenated olefins such as vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid Α, β-ethylenically unsaturated carboxylic acids such as acids, maleic acid and citraconic acid and salts thereof, (meth) acrylamide, N-methylol acrylamide, N, N′-dimethyl acrylamide, acrylamido 2-methylpropane sulfonic acid and the like (Meth) acrylamide-based monomers such as sodium salts, and other monomers such as vinylpyridine and N-vinylpyrrolidone.

In the aqueous emulsion of the present invention, the dispersant is
Polyvinyl alcohol having a mercapto group at the end (P
VA) -based polymer, and preferably, in the presence of the PVA-based polymer, one or more monomers selected from the above-mentioned (meth) acrylic acid ester, styrene-based and diene-based monomers are emulsified (co-polymerized). ) An aqueous emulsion obtained by polymerization. The PVA-based polymer having the above mercapto group is P
A polymer having a mercapto group in the main chain of the VA molecule also has a sufficient effect, but in this case, it may be insolubilized by forming a disulfide bond due to the oxidation of PVA itself, and therefore mercapto may be present only at one end of the molecule. A PVA-based polymer having a group is particularly desirable because it is easy to handle without concern about insolubilization.

The PVA-based polymer having a mercapto group only at one terminal of such a molecule is a polyvinyl ester-based polymer obtained by polymerizing a vinyl monomer mainly composed of a vinyl ester monomer in the presence of thiol acid. It can be obtained by saponification by a conventional method, and the production method will be described in detail below. First, the thiol acid used here is -COSH.
Including organic thiol acid having a group. Examples thereof include thiol acetic acid, thiol propionic acid, thiol butyric acid, and thiol valeric acid. Among them, thiol acetic acid is most preferable because of its degradability. As the vinyl ester, any vinyl ester capable of radical polymerization can be used. Examples thereof include vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, vinyl laurate, vinyl stearate, and the like. Among them, vinyl acetate is preferable because it has the highest polymerizability. It is also possible to copolymerize the vinyl ester with a copolymerizable monomer. For example, ethylene, propylene, isobutylene, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid or salts thereof, or their alkyl esters, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, trimethyl- (3-acrylamide-3) -Dimethylpropyl) -ammonium chloride, ethyl vinyl ether, butyl vinyl ether, N
-Vinylpyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, sodium allyl sulfonate and the like.

For the polymerization of vinyl monomers mainly composed of vinyl esters such as vinyl acetate in the presence of thiol acid, any of bulk polymerization method, solution polymerization method, pearl polymerization method, emulsion polymerization method, etc. can be carried out in the presence of a radical polymerization initiator. However, the solution polymerization method using methanol as a solvent is industrially most advantageous. The amount and method of addition of the thiol acid present during the polymerization to the polymerization system are not particularly limited and should be appropriately determined according to the physical properties of the intended polyvinyl ester polymer. As the polymerization method, a known method such as a batch method, a semi-continuous method, or a continuous method can be adopted. As the radical polymerization initiator, known radical polymerization initiators such as 2,2′-azobisisobutyronitrile, benzoyl peroxide, and carbonate carbonate can be used.
Azo initiators such as 2,2′-azobisisobutyronitrile are preferable because they are easy to handle. Radiation, electron beam, etc. can also be used. The polymerization temperature is preferably an appropriate temperature depending on the type of initiator used, but is usually 3
It is selected from the range of 0 to 90 ° C. After polymerizing for a predetermined time,
By removing unpolymerized vinyl esters by a usual method, a polyvinyl ester polymer having a thiol ester group at the terminal can be obtained.

The polyvinyl ester polymer thus obtained is saponified by a conventional method, but it is usually advantageous to carry out the polymer as an alcohol solution, especially as a methanol solution. As the alcohol, not only an anhydride but also a small amount of a water-containing alcohol may be used according to the purpose, and an organic solvent such as methyl acetate or ethyl acetate may be optionally contained. The saponification temperature is usually selected from the range of 10 to 70 ° C. As the saponification catalyst, alkaline catalysts such as sodium hydroxide, potassium hydroxide, sodium methylate and potassium methylate are preferable, and the amount of the catalyst used is appropriately determined depending on the degree of saponification and the amount of water. It is desirable to use a molar ratio of 0.001 or more, preferably 0.002 or more. On the other hand, when the amount of alkali is too large, it becomes difficult to remove the residual alkali from the polymer, and the polymer is colored, which is not preferable, and the molar ratio is preferably 0.2 or less. When the polyvinyl ester-based polymer contains a component that reacts with an alkali catalyst such as a carboxyl group or its ester group and consumes an alkali, the amount of the alkali catalyst added should be used. .

This saponification reaction saponifies the terminal thiol ester of the polyvinyl ester polymer having a thiol ester group at the terminal and the vinyl ester bond in the main chain, and the polymer terminal becomes a mercapto group and the main chain becomes vinyl alcohol. However, the degree of saponification of the vinyl ester unit in the main chain can be changed according to the purpose of use. After the saponification reaction, the precipitated polymer can be usually obtained as a white powder by purifying by a known method such as washing with methanol and removing impurities such as residual alkali and alkali metal salt of acetic acid and drying. The method for producing the PVA-based polymer having a mercapto group at the terminal used in the present invention has been described above. The degree of polymerization of this PVA-based polymer is preferably 3500 or less. The degree of saponification differs depending on the types of other modifying groups and cannot be unambiguously stated, but from the viewpoint of water solubility, it is preferably 70 mol% or more.

The amount of the PVA-based polymer thus obtained used is 1 to 20 with respect to the amount of the (meth) acrylic acid ester-based, styrene-based, diene-based monomers and the like.
%, Especially 2 to 10% by weight is preferred. When the amount of the PVA-based polymer used is less than 1% by weight based on the amount of the monomer, the emulsion polymerization stability decreases, and a stable aqueous emulsion is difficult to obtain, which is not preferable. On the other hand, when the amount of the PVA-based polymer used is more than 20% by weight, the sealer composition may not sufficiently exhibit the waterproof performance and the adhesion to the finishing treatment material, which may cause a problem.

Using the PVA polymer as a dispersant,
In carrying out emulsion (co) polymerization of one or more monomers selected from (meth) acrylic acid ester, styrene-based and diene-based monomers, the above-mentioned reaction is carried out in the presence of water, a dispersant and a polymerization initiator. Any ordinary emulsion polymerization method, in which an unsaturated monomer is added temporarily or continuously and then heated and stirred, can be carried out, and the unsaturated monomer is mixed with an aqueous PVA-based polymer solution in advance and emulsified. It is also possible to carry out a method of continuously adding the above. As the polymerization initiator, a redox system composed of a mercapto group at the PVA terminal and a water-soluble oxidizing agent such as potassium bromate, potassium persulfate, hydrogen peroxide can also be used. Among them, potassium bromate is It does not generate a radical by itself, but decomposes only by a redox reaction with a mercapto group at the PVA end to generate a radical, so that it effectively produces PVA and a block copolymer, and thus enhances the stabilizing effect. , A particularly preferred initiator. It is also possible to use potassium bromate at the start of the polymerization, and then to add another oxidizing agent, so that the oxidizing agent can be used in combination.

When emulsion (co) polymerization is carried out using a dispersant composed of a PVA-based polymer having a mercapto group at the terminal thereof in the present invention, it is important and desirable that the polymerization system is acidic. This is because the mercapto group, which is extremely active in radical polymerization, is ionically added to and disappears from the double bond of the monomer under basic conditions, resulting in a marked decrease in polymerization efficiency. , P depends on the type of unsaturated monomer
It is preferable to carry out at H6 or less, preferably at pH4 or less. In the present invention, P having a mercapto group is used.
The dispersant composed of a VA polymer is preferably used alone as described above, but if necessary, a conventionally known anionic, nonionic or cationic surfactant or water-soluble polymer may impair the performance. It is also possible to use them in combination as long as they are not present.

If desired, various aqueous emulsions can be added to the aqueous emulsion (B) of the present invention. Examples of the aqueous emulsion include polyvinyl acetate emulsion, ethylene-vinyl acetate copolymer emulsion, polychloroprene emulsion, polybutadiene emulsion, styrene-butadiene copolymer emulsion, butadiene-acrylonitrile copolymer emulsion, butyl rubber emulsion, polyacrylic ester. Examples include emulsions, polyvinyl chloride emulsions, polyvinylidene chloride emulsions, 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), and 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 type, a calcium silicate type, a gypsum type, sand, or a clay mineral type 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 an inorganic component composed of a compound such as Si, Ca, Mg and 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 unlikely to cause coating defects, and has a surface-layer reinforcing effect, water-stopping performance, wet water resistance and hot water resistance comparable to a solvent-based sealer in a single coating, and After being treated with a sealer, it is extremely useful as an industrial material that can obtain excellent adhesion to a finishing material even if it is left for a long time.

[0038]

EXAMPLES The present invention will be specifically described below with reference to examples, but these examples do not limit the present invention in any way. 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 stop 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 burette to the end, 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 This is 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 toilet)
(X, white) was applied, and while the solvent-type acrylic resin coating 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 topcoat paint are peeled off at the interface between the sealer-coated surface and the topcoat paint. 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 being subjected to a sealer treatment and before being subjected to a 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 post-irradiation sample 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.
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 20 g / m 2 of solid content of the composition of the present invention on a porous inorganic plate.
^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. The 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 a saponification degree of the vinyl acetate unit was 98.5 mol%.
Modified PVA containing a silyl group in the molecule with a degree of polymerization of 500
Got This modified PVA was dissolved in water to prepare a 15% aqueous solution. On the other hand, in a 1 liter glass container equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen blowing port, PVA having a mercapto group at the end (PVA-1; degree of polymerization: 60).
0, saponification degree 88.5 mol%) 15 g of ion-exchanged water 28
It was dissolved by heating in 0 g and adjusted to pH = 3.5 with diluted sulfuric acid.
Next, while stirring at 140 rpm, 55 g of methyl methacrylate and 45 g of butyl acrylate were charged, and the temperature was 60 ° C.
After the temperature was raised to 10, a 10% aqueous solution of 5% ammonium persulfate was added to initiate polymerization. 15 minutes after starting the polymerization,
Methyl methacrylate 110g, butyl acrylate 90
g, 5 g of 2-hydroxyethyl methacrylate were continuously added over 2 hours. After 5 hours, polymerization rate 99.9%
And then cooled down. The pH of the produced emulsion was adjusted to 6.8 with aqueous ammonia, the solid content concentration was 51.0%, and the viscosity was 9
A 50 cp aqueous emulsion (I) was obtained. 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.

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 procedure of Example 1 was repeated, 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.

Example 2 12 g of PVA having a mercapto group at the end (PVA-2; degree of polymerization 400, degree of saponification 98.5 mol%) was dissolved in 290 g of ion-exchanged water by heating, and the solution was charged with a nitrogen inlet and a thermometer. It was placed in a pressure-resistant autoclave equipped with it. PH with dilute sulfuric acid
= 4.0 after charging 165 g of styrene and then 135 g of butadiene from a pressure meter, and heating to 70 ° C,
Polymerization was initiated by pressing in 10 g of a 2% aqueous solution of potassium persulfate. The internal pressure decreased from 4.8 kg / cm ^{2 as the} polymerization progressed, and after 15 hours reached 0.4 kg / cm ² , and the polymerization rate was determined to be 99.3%. The obtained emulsion was adjusted to pH = 6.0 with aqueous ammonia, and the solid content concentration was 49.0.
%, An aqueous emulsion (II) having a viscosity of 2600 cp was obtained. A sealer composition was obtained and tested in the same manner as in Example 1 except that the aqueous emulsion (I) of Example 1 was replaced with the aqueous emulsion (II). The results are shown in Table 1.

Comparative Example 6 PVA having a mercapto group at the end of Example 1 (PVA
-1), instead of a nonionic surfactant (Nonipol 2
00, manufactured by Sanyo Kasei Co., Ltd.)
As in Example 1, solid content concentration 50.8%, viscosity 75c
An aqueous emulsion (III) with p, pH = 6.8 was obtained. The aqueous emulsion (I) of Example 1 was replaced with the aqueous emulsion (II
A sealer composition was obtained and tested in the same manner as in Example 1 except that I) was used instead. The results are shown in Table 1.

Example 3 With respect to 100 parts of the composition of Example 1, a water-dispersible isocyanate compound (Coronate C-3 as a waterproofing agent was further added.
053; manufactured by Nippon Polyurethane Industry Co., Ltd.) was added and the same test as in Example 1 was performed. The results are shown in Table 1.

[0054]

[Table 1]

[0055]

[Table 2]

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

Examples 4 to 6 and Comparative Examples 7 and 8 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 2, and the same performance evaluation as in Example 1 was performed on this. The results are shown in Table 2.

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

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.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C09D 5/34 PRC 7211-4J 129/04 PFN 6904-4J

Claims (3)

[Claims] 1. A modified polyvinyl alcohol (A) containing a silyl group in an amount of 0.01 to 5 mol%, a dispersoid of which is an acrylic acid ester-based monomer unit, a methacrylic acid ester-based monomer unit, and styrene. A homopolymer or a copolymer containing one or more monomer units selected from a monomer unit and a diene monomer unit, wherein the dispersant is a polyvinyl alcohol polymer having a mercapto group at the terminal. A composition comprising a certain aqueous emulsion (B) and having a solid content blending ratio (A) / (B) on a weight basis of 5/95 to 50/50. 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.