JPH0764658B2 - Sealer composition for porous inorganic plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a sealer composition which is applied in advance so as to effectively perform a surface cosmetic finish of a porous inorganic plate.

Since calcium silicate board, gypsum board, ALC board, rock wool board, etc. are all porous, the surface layer strength is low and it easily absorbs moisture. For example, it has a beautiful finish and peels off the inorganic plate, it peels off immediately even if it finishes well, and when it absorbs water or moisture, the finishing material peels off due to repeated freeze-thawing. There is a problem in terms.

The sealer is applied before finishing treatment in order to prevent these troubles. This sealer treatment may be performed on the inorganic plate manufacturing line of the factory, or may be performed at the finishing treatment on the construction site.

(B) Prior art and problems The sealer-treated inorganic plate is left as it is for several months as a commercial product, or is exposed to rainwater, outside air, etc. for several months before being used for construction and finished with makeup. There is. For this reason, three required properties are largely required: the reinforcing effect on the surface of the inorganic plate, the water stopping performance, and the adhesion to the finishing material.

Conventionally, solvent-based sealers such as urethane resin-based, epoxy resin-based, and vinyl chloride resin-based sealers have been mainly used, and as a typical one, a one-component moisture-curable urethane resin-based sealer is known. Although this one has a good surface layer reinforcing effect and water blocking performance, if it is left for a long time while being treated with a sealer, the coating film will be excessively hardened, and the initially good adhesion with the finishing agent will decrease. There are problems in terms of safety and hygiene because it is a solvent system, and there is a problem in that the solvent used as a diluent is expensive and it is expensive to collect because it is a mixed solvent.

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 that no solvent is used at all, since the surface layer reinforcing effect of the inorganic plate is extremely small, there is no problem for the time being when finishing treatment, but peeling occurs at the surface layer of the inorganic plate after several months. However, there is a problem that it cannot be used with confidence. In terms of water-stopping performance, it is difficult to obtain a sufficiently satisfactory product, even though it is originally a hydrophobic resin. The reason is that the thickener used together decreases the water resistance of the coating film, and defects during coating are more likely to occur than in 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, it is concentrated and permeates into that part, so that it is difficult to form a uniform coating liquid film. This is probably due to the holes.

Polyvinyl alcohol (hereinafter, polyvinyl alcohol is referred to as PVA
(Hereinafter abbreviated as ") and an aqueous emulsion have been proposed (JP-A-53-97018). However, the fact is that even with this method, the surface layer reinforcing effect and the water blocking performance of the above-mentioned inorganic plate have not been sufficiently improved.

Further, an aqueous sealer made of modified PVA having a silyl group in the molecule (JP-A-58-167485) or an aqueous sealer made of synthetic resin emulsion containing modified PVA having a silyl group in the molecule as an emulsifier (JP-A-58-167485). 171457)
Is also known. These methods are remarkably improved in the surface reinforcement effect of the inorganic plate or the adhesiveness with the inorganic plate as compared with the conventional water-based sealer and are excellent methods in that respect, but the water-stopping performance is insufficient in some cases. In addition, when the surface decorative finish is an acrylic paint, there is a problem in that the adhesion with the finishing agent may be low.

(C) Means for Solving the Problems As a result of intensive investigations by the present inventors to overcome the above drawbacks,
(A) Modified PV having 0.01 to 5 mol% of silyl groups in the molecule
A and (B) are blended with α-olefin emulsion, and the solid content weight ratio (A) / (B) of both is 5 /.
With a sealer composition consisting of 95-50 / 50,
Although it is an aqueous system with no safety and health problems, coating defects are unlikely to occur with a single coating, the surface reinforcement effect and water-stopping performance are comparable to solvent-based sealers, and finish even if left standing for a long time with sealer treatment. The inventors have found that the adhesiveness with the material does not decrease, and have completed the present invention.

Modified PVA having a silyl group in the molecule used in the present invention
May be any as long as it contains silicon in the molecule, but the silyl group contained in the molecule may be an alkoxyl group, an acyloxyl group or a reactive substituent such as a silanol group or a salt thereof which is a hydrolyzate thereof. Those which have are particularly preferably used.

As a method for producing such modified PVA, PVA or modified polyvinyl acetate containing a carboxyl group or a hydroxyl group, a method of introducing a silyl group by post-modification using a silylating agent, vinyl ester and silyl group-containing olefinic unsaturated Examples include a method of saponifying a copolymer with a monomer, and a method of saponifying a polyvinyl ester having a silyl group at a terminal obtained by polymerizing a vinyl ester in the presence of a mercaptan having a silyl group. .

In the method of post-modifying PVA or modified polyvinyl acetate with a silylating agent, for example, the silylating agent is added to an organic solvent that does not react with the silylating agent, such as benzene, toluene, xylene, hexane, heptane, ether or acetone. Dissolve and suspend the powdered PVA or the above modified polyvinyl acetate in the solution with stirring, and at a temperature in the range of room temperature to the boiling point of the silylating agent, the silylating agent and PVA.
Alternatively, a silyl group-containing modified PVA can be obtained by reacting the modified polyvinyl acetate or by saponifying the vinyl acetate unit with an alkali catalyst or the like.

Examples of the silylating agent used in the post-modification include trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, diphenyldichlorosilane, organohalogensilanes such as triethylfluorosilane, trimethylacetoxysilane, and dimethyldichlorosilane. Organosilicon ester such as acetoxysilane, trimethylmethoxysilane, organoalkoxysilane such as dimethyldimethoxysilane, trimethylsilanol, organosilanol such as diethylsilanediol, aminoalkylsilane such as N-aminoethylaminopropyltrimethoxysilane, trimethylsilicon isocyanate. And organosilicon isocyanate.

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. The degree of polymerization and saponification of the obtained modified silyl group-containing PVA can be arbitrarily adjusted by the degree of polymerization of the PVA used, the degree of saponification or the degree of polymerization of the above-mentioned modified polyvinyl acetate, and the saponification reaction.

Further, in the method of saponifying a copolymer of a vinyl ester and a silyl group-containing olefinic unsaturated monomer, for example, a vinyl ester and a silyl group-containing olefinic unsaturated monomer in an alcohol are used as a radical initiator. A silyl group-containing modified PVA can be obtained by copolymerizing the copolymer with an alcohol and then adding an alkali or acid catalyst to the alcohol solution of the copolymer to saponify the copolymer. Examples of the vinyl ester used in the above method include vinyl acetate, vinyl propionate, vinyl formate, etc., but vinyl acetate is preferable from the economical viewpoint.

The silyl group-containing olefinic unsaturated monomer used in the above method is a vinylsilane represented by the following formula (I) or a (meth) acrylamide represented by (II).
An alkyl silane is mentioned.

[Here, n is 0 to 4, m is 0 to 2, R ¹ is an alkyl group having 1 to 5 carbon atoms (methyl, ethyl, etc.), and R ² is 1 to 40 carbon atoms.
Alkoxyl group or acyloxyl group (wherein 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 R ⁵ represents an alkylene group having 1 to 5 carbon atoms or a divalent organic residue in which chain carbon atoms are bonded to each other by oxygen or nitrogen. Note if R ¹ has two or more in the same monomer may be filed R ¹ is the same as, or shall apply different. Also, when R ² has two or more in the same monomer, 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 (Here, R ¹ and m are the same as above, and x is 1 to 20) and the like, and polyethylene glycolated vinyl silane and the like can be mentioned.

Specific examples of the (meth) acrylamide-alkylsilane represented by the formula (II) include 3- (meth) acrylamide-propyltrimethoxysilane, 3- (meth) acrylamide-propyltriethoxysilane and 3
-(Meth) acrylamide-propyltri (β-methoxyethoxy) silane, 2- (meth) acrylamide-2
-Methylpropyltrimethoxysilane, 2- (meth) acrylamido-2-methylethyltrimethoxysilane,
N- (2- (meth) acrylamide-ethyl) -aminopropyltrimethoxysilane, 3- (meth) acrylamide-propyltriacetoxysilane, 2- (meth) acrylamide-ethyltrimethoxysilane, 1- (meth) acrylamide- Methyltrimethoxysilane, 3-
(Meth) acrylamide-propylmethyldimethoxysilane, 3- (meth) acrylamide-propyldimethylmethoxysilane, 3- (N-methyl- (meth) acrylamide) propyltrimethoxysilane, 3-((meth))
Acrylamide-methoxy) -3-hydroxypropyltrimethoxysilane, 3-((meth) acrylamido-methoxy) -propyltrimethoxysilane, N, N-dimethyl-N-trimethoxysilylpropyl-3- (meth) acrylamido-propyl Examples thereof include ammonium chloride and N, N-dimethyl-N-trimethoxysilylpropyl-2- (meth) acrylamido-2-methylpropylammonium chloride.

Further, in producing the modified PVA used in the present invention, in copolymerizing the vinyl ester and the silyl group-containing olefinic unsaturated monomer, the monomer other than the above two components is used. Other copolymerizable unsaturated monomers, for example, styrene, alkyl vinyl ether, vinyl versatate, olefins such as (meth) acrylamide, ethylene, propylene, α-hexene and α-octene,
Unsaturated acids such as (meth) acrylic acid, crotonic acid, maleic acid (anhydrous), fumaric acid, itaconic acid, and their alkyl esters, alkali salts, 2-acrylamido-2-
Sulfonic acid-containing monomers such as methylpropanesulfonic acid and alkali salts thereof, trimethyl-3- (1- (meth) acrylamide-1,1-dimethylpropyl) ammonium chloride, trimethyl-3- (1- (meth) acrylamide Propyl) ammonium chloride, 1-vinyl-2
It is also possible to allow a small proportion of cationic monomers such as -methylimidazole and quaternary compounds thereof to be present.

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, for example, when the vinyl ester is polymerized using a radical initiator, , A mercaptan having a silyl group is added to the polymerization system at once or in a divided or continuous manner so that the mercaptan having the silyl group is present in the polymerization system, and a polyvinyl ester having a silyl group at the terminal is formed by chain transfer to the mercaptan. After the formation, a modified PVA having a silyl group can be obtained by adding an alkali or acid catalyst to the alcohol solution of the polyvinyl ester to saponify the polyvinyl ester.

As the mercaptan having a silyl group used in this method, 3- (trimethoxysilyl) -propylmercaptan, 3- (triethoxysilyl) -propylmercaptan and the like can be used. Modified PVA with silyl group by this method
It is also possible to allow a small proportion of an unsaturated monomer copolymerizable with the vinyl ester used in the method of producing a.

Although the modified PVA containing a silyl group in the molecule has been described in detail above, the copolymerized PVA is more preferable than the post-modified one in terms of easiness of industrial production. Further, among the modified PVA by copolymerization, the saponification product of a copolymer with a silyl group-containing olefinic unsaturated monomer represented by the formula (I) is a solution having a viscosity stability of an aqueous solution and an alkali solution when an alkaline aqueous solution is used. It is preferably used because it is excellent in stability against water or water resistance when formed into a film.

The modification degree of the modified PVA obtained by the above three methods, that is, the silyl group content in the modified PVA is 0.01 to 5 mol% as a monomer unit containing a silyl group in the molecule, and preferably 0.1.
It is 1 to 1.0 mol%, more preferably 0.1 to 0.6 mol%.

When the content of the silyl group is less than 0.01 mol%, the effect of reinforcing the surface layer of the inorganic plate is not obtained, and when it is more than 5 mol%, the stability of the α-olefin emulsion used together becomes poor, so that the water-stopping property is poor. Alternatively, it is not preferable because the adhesiveness with the finishing material decreases. In order to cause the pseudo-collection of α-olefin emulsion as described below, 0.1 to 1.0 is required.
Mol%, more preferably 0.1 to 0.6 mol%.

The degree of polymerization of modified PVA (both post-modified PVA and modified PVA by copolymerization) is usually 100 to 3000, preferably 300 to 2000, and the degree of saponification is selected from the range of 70 to 100 mol%.

The silyl group-containing modified PVA thus obtained was dispersed in water, and in some cases, a small amount of sodium hydroxide, potassium hydroxide, ammonium hydroxide, amine or another alkali was added, and the mixture was heated with stirring. By doing so, a uniform aqueous solution can be obtained.

As the α-olefin emulsion in the present invention, isoprene, isobutene, butadiene, styrene,
An emulsion containing one or more components selected from the group consisting of vinyl chloride, vinylidene chloride, acrylonitrile and the like. The ionicity of emulsion is preferably nonionic or anionic.

In the sealer composition of the present invention, the compounding composition of (A) the modified PVA having 0.01 to 5 mol% of silyl groups in the molecule and (B) the α-olefin emulsion is (A) / (solid content weight ratio). It is necessary that (B) = 5/95 to 50/50, and the purpose of the present invention is achieved only by doing so.

Further, the sealer composition of the present invention has a silyl group of 0.
The modified PVA containing 01 to 5 mol% and α-olefin emulsion are blended. In the above both blends, an aqueous solution of PVA containing a silyl group is stirred in α-olefin emulsion. The method of mixing is preferable. Further, inorganic pigments such as calcium carbonate, clay, titanium oxide, zinc oxide and red iron oxide, urea as a stabilizer for the coating liquid, defoaming agents and the like may be dispersed and mixed for use. Further, it can be diluted with water at the end so as to obtain a coating solution having an appropriate viscosity.

(A) PVA containing silyl group and (B) for general use
The α-olefin emulsion has sufficient hot water resistance, but in some cases, if a higher level of hot water resistance is required, it is necessary to further use (C) a water resistant agent in order to improve the heat resistance of the sealer coating film. It is preferable in improving the aqueous property. When (A) / (B) = 5/95 to 50/50, the compounding ratio of the water-proofing agent needs to be (A) / (C) = 99.5 / 0.5 to 10/90. As the water-proofing agent, colloidal silica, water glass, borax, epoxy resin, polyamide resin, melamine resin, polyamide methylol resin, polyethyleneimine, etc. are preferable. Among them, colloidal silica (A) /
When (C) = 70/30 to 20/80 is blended, a particularly remarkable effect is obtained.

Coating solution concentration is 10-60% (solid content concentration), preferably 20-40
% (Solid content concentration).

The porous inorganic plate to which the sealer composition of the present invention is applied, cement-based, calcium silicate-based, gypsum-based, sand,
Inorganic materials such as clay minerals are the main components, and concrete examples are 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, etc. are included, but organic components are also included, but in general, both are Si,
The main component is an inorganic component composed of a compound such as Ca, Mg and Al.

As a coating method for the inorganic plate, any general coating method such as brush coating, spray coating, roller coating, flow coater, and dipping can be used. The coating amount is 0 as dry solids.
5 to 100 g / m ² is preferable, and the drying can be air drying at room temperature or heat drying.

(D) Action and Effect of the Invention The present invention comprises (A) a modified PVA having a silyl group in the molecule of 0.01 to 5 mol% and (B) an α-olefin emulsion, and the solid content weight ratio of both ( A) / (B) is 5 /
A sealer composition for porous inorganic plates in the range of 95 to 50 / 50.Although it is a water-based composition, it is unlikely to cause coating defects. It has a very high utility value as an industrial material that has excellent adhesion to the finishing material even after being left for a long time after the sealer treatment.

The reason why the sealer composition of the present invention exerts extremely excellent performance as described above is not clear, but it is presumed as follows. That is, by observing the sealer composition of the present invention under a microscope, a phenomenon peculiar to the mixed state of the main component, modified PVA having a silyl group in the molecule, and α-olefin emulsion was observed. It is not that the particles of α-olefin emulsion are dispersed uniformly as islands in the sea of an aqueous solution of silyl group-containing modified PVA, but several tens to several hundred times the original particle size. It was discovered that the size of was causing pseudo-collection. The term "pseudo-aggregation" is used here. When this aggregation state is diluted with water, it forms a light-structured particle group that is dispersed to the order of the original primary particles. Because.

Due to such a mixed state, when the sealer composition of the present invention is applied to the porous inorganic plate, a silyl group-containing modified PVA which is one component is mainly present inside the inorganic plate as compared with the case of a uniform mixed state. Easy to penetrate, another component α
It is considered that the olefin emulsion has a very small amount of permeation because it forms a group of particles extremely larger than the pores on the surface of the inorganic plate, and a film having a composition rich in α-olefin emulsion is formed on the surface layer. Moreover, since the composition of both the silyl group-containing modified PVA and the α-olefin emulsion in the coating thickness direction is continuously changing, the surface layer film does not easily peel off from the inorganic plate, and water blocking performance is demonstrated. It must have been done. 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 (JP-A-58-164604). The permeation into the inorganic plate could be adjusted appropriately, and the resulting surface reinforcement effect was extremely good. On the other hand, α-olefin emulsion is originally a hydrophobic resin, and it is considered that the water resistance of the coating film of the inorganic plate was obtained because the water resistance of the film was good. Further, the silyl group-containing modified PVA of the sealer composition of the present invention will always permeate into a large hole on the surface of the inorganic plate with some emulsions, but this modified PVA is a component of the inorganic plate. Since it has a strong interaction with the inorganic plate, it forms a gel film with excellent water resistance at an appropriate depth from the surface layer of the inorganic plate, so the coating solution does not penetrate excessively, and as a result, coating defects are less likely to occur. It is considered that good water stopping performance was obtained.

It is considered that the above-mentioned appropriate permeability to the inorganic plate is still caused, and it is considered to be due to the degree of pseudo-pseudo-collection obtained by the compounding ratio of the silyl group-containing modified PVA and the α-olefin emulsion.

Furthermore, by using a water resistant agent such as colloidal silica, water glass, borax, epoxy resin, polyamide resin, polyamide methylol resin, and polyethyleneimine together, the silyl group-containing modified PVA is made water resistant, and as a result, the resistance of the coating film is improved. It is considered that hot water and hot water resistance are significantly improved.

Hereinafter, the present invention will be specifically described with reference to examples, but these examples do not limit the present invention in any way. Unless otherwise specified, all parts or percentages are by weight. The test methods used in the examples are as follows.

(1) Water Permeability Test In a test for checking 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 at 80 ° C.
After drying for 20 minutes, it was left standing at 20 ° C. and 65% RH for 7 days.

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 the birelet to the end, add water so that the initial head is 25 cm, and decrease the amount of water after 8 hours. I read it. The smaller the value, the better the waterproof performance.

(2) Adhesion test A test for checking the reinforcing effect of the surface layer of the porous inorganic plate by the sealer and the adhesion between the surface layer of the inorganic plate and the top-coating finishing agent. The test body described in (1) was top-coating finishing agent. As a solvent type acrylic resin paint (manufactured by Toa Paint Co., Ltd.,
Acrylic DX for toilet, white) was applied, and while it was not dried, a cotton cloth was placed on it and dried at room temperature for 2 days. After that, make a cut in a 1 cm width with a knife, and use an autograph (manufactured by Shimadzu Corp., IM-100 type) to peel at 90 °,
The peeling resistance was measured at 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 of the inorganic plate have a 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 before being subjected to a cosmetic finish after being treated with a sealer. 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. In the test for observing weather resistance by such an outdoor exposure route, the sealer-treated sample described in (1) was irradiated with a xenon lamp (Shimadzu Corporation, XW-60V3, 6KW) for 200 hours at 40 ° C and every 2 hours. Water was sprayed for 18 minutes 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 This is a test to check the stability of the liquid during the coating of the sealer, and a Marlon tester (MARON 1000 rpm manufactured by Shinsei Sangyo Co., Ltd.) is used to shear a load of 50 kg with a load of 25 kg at 1000 rpm for 10 minutes. A force was applied to check the generation amount of the gelled product (expressed by weight% based on the solid content of 50 g of the coating liquid after separating and drying the gelled product with 100 mesh wire mesh).

(5) Warm water resistance test A porous inorganic plate was coated with the composition of the present invention at a solid content of 20 g / m ² ,
It was dried at room temperature for 2 days. This coating was immersed in warm water at 50 ° C. for 2 consecutive weeks, and swelling of the top coating 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 and} dried at 130 ° C. for 20 minutes, and then a solvent-based acrylic resin paint (Toa Paint Co., Ltd., for tore tiles) Acrylic DX,
White) was applied and dried at room temperature for 2 days. 80 this coating
It was immersed in hot water at 0 ° C. for 2 hours, and swelling of the top-coat paint was observed.

Example 1 A copolymer of bilyltrimethoxysilane and vinyl acetate was saponified to contain a silyl group as a vinylsilane unit in an amount of 0.5 mol%. The vinyl acetate unit had a saponification degree of 98.5 mol% and a polymerization degree of 500. A modified PVA containing groups was obtained. This modified PVA was dissolved in water to prepare a 15% aqueous solution.

Vinyl chloride emulsion (made by Nippon Zeon Co., Ltd., Geon
576, anionic, solid content 55%) 92 parts of the modified PVA 15% aqueous solution described above was mixed with stirring, and correction water was added to obtain a sealer composition having a concentration of 25%. Table 1 shows the results of evaluating the performance by applying this sealer to a calcareous plate (apparent density 1.0).

Example 2 Instead of the vinyl chloride emulsion of Example 1, a vinylidene chloride emulsion (Yukaka Verdishyu Co., Ltd.) was used.
Manufactured by Diffon 207DC, anionic, solid content 55%) was used in the same manner as in Example 1. The results are shown in Table-1
Shown in.

Example 3 The same procedure as in Example 1 was repeated except that 110 parts of acnylonitrile-butadiene copolymer emulsion (manufactured by Nippon Zeon Co., Ltd., Hycar 1551, solid content 50%) was used instead of the vinyl chloride emulsion of Example 1. Ivy. The results are shown in Table-1.

Example 4 The same as Example 1 except that 115 parts of a styrene-butadiene copolymer emulsion (manufactured by Japan Synthetic Rubber Co., Ltd., # 0680, solid content 48%) was used instead of the vinyl chloride emulsion of Example 1. I went to. The results are shown in Table-1.

Comparative Examples 1 to 6 The procedure of Example 1 was repeated, except that the following sealer was used instead of the sealer composition of Example 1. The results are shown together in Table 1.

Comparative Example 1: Only the modified PVA aqueous solution used in Example 1.

Comparative Example 2: A solution prepared by using the vinyl chloride emulsion used in Example 1 to a concentration of 25%.

Comparative Example 3: Instead of the modified PVA used in Example 1, PVA-
A solution using 105 (PVA manufactured by Kuraray Co., Ltd., polymerization degree 550, saponification degree 98.5 mol%).

Comparative Example 4: Vinyl acetate emulsion obtained by using the modified PVA used in Example 1 as an emulsion stabilizer (25%
liquid).

Comparative Example 5: Existing solvent-based urethane sealer ("Abestos Sealer # 20" manufactured by Toa Paint Co., Ltd.).

Comparative Example 6: No sealer applied.

As shown in Table 1, the sealer 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 (immediately and after weathering).

Examples 5 to 8 and Comparative Examples 7 to 8 The procedure of Example 1 was repeated, except that the modified PVA and vinyl chloride emulsion in Example 1 were mixed in the following weight ratios. The results are shown together in Table 2.

Example 9 A silyl group obtained by saponifying a copolymer of vinyltriacetoxysilane and vinyl acetate, which contains 0.2 mol% of a silyl group as a vinylsilane unit, and a saponification degree of the vinyl acetate unit of 98.5.
Modified PVA containing silyl group in the molecule with mol% and degree of polymerization of 1000
Got This modified PVA was dissolved in water to obtain a 15% aqueous solution. Using this modified PVA aqueous solution, a sealer composition was obtained in the same manner as in Example-1. Table 3 shows the results of evaluating the performance of this coating solution applied to a silica sheet (apparent density 1.0).

Examples 10 to 13 and Comparative Examples 9 to 10 Instead of the modified PVA used in Example 9, modified PVA obtained by saponifying a copolymer of vinyltrimethoxysilane and vinyl acetate as shown in Table-3. Example 9 was repeated except for using. The results are shown together in Table-3.

Examples 14 to 17 Except that 100 parts of the sealer composition of Example 1 was added with 35 parts of the following waterproofing agent (all prepared to a solid content of 20% and used), and the test was conducted. I went as well. The results are shown together in Table-4.

Example 14: When colloidal silica (manufactured by Catalysts & Chemicals Industry Co., Ltd., SI-500) was used as a water resistant agent.

Example 15: When a polyamide resin (Sumitomo EX70M manufactured by Sumitomo Chemical Co., Ltd.) is used as a water resistant agent.

Example 16: When a polyamide methylol resin (Sumitomo Chemical Co., Ltd., Sumireze 633) is used as a water resistant agent.

Example 17: Using polyethyleneimine (Nippon Shokubai Kagaku Co., Ltd., Epomin SP1000) as a waterproofing agent.

Comparative Example 11 When the hot water resistance test was additionally performed for Example 1. The results are shown in Table-4.

Examples 18 to 20, Comparative Examples 12 to 13 The procedure of Example 14 was repeated except that the modified PVA and colloidal silica in Example 14 were mixed in the following solid content ratios. The results are shown together in Table-5.

Example 21 The performance of applying a pigmented white sealer composition obtained by adding 0.27 part of urea and 10 parts of titanium dioxide powder to 100 parts of the sealer composition of Example 1 on a calcareous plate (apparent density 1.0) is shown in Table-6.
Shown in.

Example 22 A pigmented red sealer composition prepared by adding 0.27 part of urea, 10 parts of titanium dioxide powder and 0.2 part of red iron oxide to the sealer composition of Example 1 was applied to a calcareous plate (apparent specific gravity: 0.8). The results are shown in Table-6.

By adding the pigment, a sealer composition having a better waterproof property was obtained. In addition, the sealer-treated silica sheet has a coating value that is less noticeable due to the addition of a pigment, and the product value is improved because it is white or red.

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Claims (3)

[Claims] 1. A modified polyvinyl alcohol having a silyl group in the molecule of 0.01 to 5 mol%, and (B) an α-olefin emulsion are blended, and the solid content weight ratio (A) / (B) of the both. A sealer composition for a porous inorganic plate, which is in the range of 5/95 to 50/50. 2. (A) 0.01 to 5 mol% silyl group in the molecule
The sealer for a porous inorganic plate according to claim 1, wherein the modified polyvinyl alcohol has a saponified product of a copolymer of vinyl ester and an olefinically unsaturated monomer having a silyl group in the molecule. Composition. 3. (A) 0.01 to 5 mol% silyl group in the molecule
The modified polyvinyl alcohol, (B) α-olefin emulsion and (C) (A) water resistant agent are blended, and the solid content weight ratio (A) / (B) is from 5/95.
A sealer composition for a porous inorganic plate, characterized in that 50/50 and (A) / (C) are in the range of 99.5 / 0.5 to 10/90.