JP2503021B2 - 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 decorative 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 production line of the factory or may be performed at the finishing treatment on the construction site, but the present invention mainly relates to the case of performing the sealer treatment on the inorganic plate production line of the factory. .

(B) Prior art and problems The sealer-treated inorganic plate should be left as a product for several months in that state, or 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 type sealers such as urethane resin type, epoxy resin type, vinyl chloride resin type are mainly used,
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,
It is known that the main component is acrylic emulsion. Although this has the advantage that no solvent is used at all, the effect of reinforcing the surface layer of the inorganic plate is extremely small, so there is no problem for the time being when the finishing treatment is performed, 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. Regarding 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.

As a method of improving such a drawback of the water-based sealer, polyvinyl alcohol (hereinafter, polyvinyl alcohol is referred to as PV
A method in which abbreviated as A) and an aqueous emulsion are used in combination is 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). 17145
7) is also known. These methods are remarkably improved in the surface layer reinforcing effect of the inorganic plate or the adhesiveness with the inorganic plate as compared with the conventional water-based sealer, and they are excellent methods in that respect, but the water-stop performance is sometimes insufficient. 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.

Furthermore, the inventor of the present application has found that a modified PV having a silyl group in the molecule.
A and a sealer composition mainly composed of acrylic emulsion having a glass transition temperature of 5 to 50 ° C. (JP-A-61-00)
4059) and a sealer composition (Japanese Patent Application No. 61-287414) in which a water-proofing agent is also used.
When drying at the above high temperature, there is a problem that the surface layer reinforcing effect is low.

Furthermore, when a sealer is applied to a plate with a high water content of 20% or more immediately after papermaking and the plate and the sealer are dried at the same time, the conventional sealer has a problem that the surface layer reinforcing effect is extremely low. ing.

(C) Means for Solving the Problems As a result of intensive studies to overcome the above-mentioned drawbacks, the present inventors have found that (A) a modified PVA having 0.01 to 5 mol% of silyl groups in the molecule and (B) a glass transition. Temperature is higher than 50 ℃, 120 ℃
When a sealer composition containing the following acrylic emulsion as a main component and having a solid content weight ratio (A) / (B) of both in the range of 5/95 to 50/50 is used, there is no problem in safety and health. However, coating defects are unlikely to occur with a single coating, the surface layer reinforcing effect and water blocking performance are comparable to solvent-based sealers, and the adhesion with the finishing material is reduced even if left for a long time with the sealer treatment. I did not find it.

Further, (A) a modified PVA having a silyl group in the molecule of 0.01 to 5 mol%, (B) a glass transition temperature higher than 50 ° C., 120
Acrylic emulsion having a temperature of ℃ or less and (C) (A)
Water resistant agent as the main component, and solid content weight ratio (A) /
(B) is 5/95 to 50/50, (A) / (C) is 99.5 / 0.5 to 10 /
When a sealer composition having a range of 90 is used, a sealer coating is applied to a plate having a high water content of 20% or more, and even when the plate is dried and the sealer is dried at the same time, a coating defect occurs in one coating. It is difficult to generate, the surface layer reinforcing effect and water blocking performance are comparable to solvent-based sealers, and it was found that the adhesion with the finishing material does not decrease even if left for a long time while being treated with a sealer.
The present invention has been completed because the process can be greatly streamlined.

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

Examples of the silyl group-containing olefinic unsaturated monomer used in the above method include vinylsilane represented by the following formula (I) and (meth) acrylamide-alkylsilane represented by (II).

[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 two or more R ^2's are contained in the same monomer, R ^2's may be the same or different. ] Specific examples of the vinylsilane represented by the formula (I) include:
For example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris- (β-methoxyethoxy) silane, vinyltriacetoxysilane, allyltrimethoxysilane, allyltriacetoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiethoxy. Silane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, vinyldimethylacetoxysilane, vinylisobutyldimethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltrihexyloxysilane, vinylmethoxydihexyloxysilane, vinyltrioctyl Roxysilane, vinyldimethoxyoctyloxysilane, vinylmethoxydioctyloxysilane, vinylmethoxydilauryloxysilane, Cycloalkenyl 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.

Further, the (meth) acrylamide represented by the formula (II)
Specific examples of the alkylsilane include, for example, 3- (meth)
Acrylamido-propyltrimethoxysilane, 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) acrylamide-propyldimethylmethoxysilane, 3- (N-methyl- (meth) acrylamide) propyltrimethoxysilane, 3-((meth) acrylamide-methoxy ) -3-Hydroxypropyltrimethoxysilane, 3-((meth) acrylamide-methoxy) -propyltrimethoxysisilane, N,
N-dimethyl-N-trimethoxysilylpropyl-3-
(Meth) acrylamido-propylammonium chloride, N, N-dimethyl-N-trimethoxysilylpropyl-2- (meth) acrylamido-2-methylpropylammonium chloride and the like can be mentioned.

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 unsaturated monomers copolymerizable,
For example, styrene, alkyl vinyl ether, vinyl versatate, (meth) acrylamide, ethylene, propylene, α-hexene, olefin such as 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 its quaternary compound 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 PV with silyl group by this method
It is also possible to allow a small proportion of the unsaturated monomer copolymerizable with the vinyl ester used in the method of producing A to be copolymerized.

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. Among modified PVA by copolymerization, (I)
Saponified copolymer of silyl group-containing olefinic unsaturated monomer represented by the formula, viscosity stability of the aqueous solution, alkali stability when made into an alkaline aqueous solution, or water resistance when formed into a film It is excellent and is preferably used.

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, preferably
It is 0.1 to 1.0 mol%, more preferably 0.1 to 0.6 mol%.

If 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 if it is more than 5 mol%, the stability of the acrylic emulsion used in combination becomes poor.
It is not preferable because the water-stopping property or the adhesion to the finishing material is lowered. In order to cause pseudo-aggregation of acrylic emulsion as described later, 0.1 to 1.0 mol%, more preferably 0.1 to 0.6 mol% is preferable.

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

The silyl group-containing modified PVA thus obtained is dispersed in water, and in some cases, a small amount of alkali such as sodium hydroxide, potassium hydroxide, ammonium hydroxide or amine is added, and the mixture is heated with stirring. As a result, a uniform aqueous solution can be obtained.

Further, as the acrylic emulsion in the present invention,
Glass transition of the film with all acrylic resin emulsion mainly composed of acrylic acid or methacrylic acid alkyl ester monomer (alkyl group has 1 to 10 carbon atoms) and acrylic copolymer resin emulsion containing styrene and vinyl acetate. Temperature (abbreviated as Tg below) is higher than 50 ℃, 12
It should be 0 ° C or lower, preferably in the range of 60 to 100 ° C. When the water content of the plate is high and it is dried at high temperature, the surface layer reinforcing effect is low when the Tg of the emulsion is 50 ° C or less, and when the Tg exceeds 120 ° C, it is produced by high temperature drying of a normal inorganic plate coating line. It is not preferable because the film becomes defective and the water blocking property decreases. The ionicity of emulsion is preferably nonionic or anionic.

As the water resistant agent in the present invention, colloidal silica,
Water glass, borax, epoxy resin, polyamide resin, melamine resin, polyamide methylol resin, polyethyleneimine and the like are used, but colloidal silica is preferable.

The sealer composition of the present invention is mainly composed of (A) a modified PVA having 0.01 to 5 mol% of silyl groups in the molecule and (B) an acrylic emulsion having a glass transition temperature of more than 50 ° C and 120 ° C or less. , And the solid content weight ratio of both (A) /
It is necessary that (B) is in the range of 5/95 to 50/50.
Furthermore, when the water content of the plate is 20% or more, (A),
(B) and (C) (A) water resistant agent as a main component, and the solid content weight ratio (A) / (B) is 5/95 to 50/50,
It is necessary that (A) / (C) be in the range of 99.5 / 0.5 to 10/90, 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 as described above.
Modified PVA containing 0.01 to 5 mol% and Tg higher than 50 ℃, 1
An acrylic emulsion in the range of 20 ° C or less, and if necessary, a water-proofing agent as a main component. In the above three formulations, the acrylic emulsion contains a silyl group.
When the aqueous solution of PVA is mixed with stirring and the water resistant agent is also used in combination, it is preferable to mix the water resistant agent at the end, and it is particularly preferable to mix the water resistant agent immediately before coating the sealer. 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. The coating liquid concentration is 10 to 60% (solid content concentration), preferably 20 to 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,
It is composed mainly of inorganic materials such as sand and clay minerals. Specifically, 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., and organic components are also contained, but in each case, the main component is usually an inorganic component composed of compounds such as Si, Ca, Mg and Al.

As for the method of applying to the inorganic plate, any general applying method such as spray coating, roller coating, flow coater, and dipping can be used. The coating amount is 0.5 to 100 g / dry solid content.
m ² is preferred.

In the case of the present invention, the effect of the present invention is more remarkable when the drying is heating drying at 100 ° C. or higher.

(D) Action and Effect of the Invention The present invention provides (A) a modified PVA having a silyl group in the molecule of 0.01 to 5 mol%, and (B) an acrylic emulsion having a Tg of more than 50 ° C. and 120 ° C. or less. When the main component is used and the solid content weight ratio (A) / (B) is in the range of 5/95 to 50/50, and the water content of the plate is 20% or more, (A),
(B) and (C) (A) as a main component, and the solid content weight ratio (A) / (B) is 5/95 to 50/50,
(A) / (C) is a sealer composition for porous inorganic plates having a range of 99.5 / 0.5 to 10/90. It is water-based and does not easily cause coating defects. It is comparable to a solvent-based sealer in a single coating. It has extremely high utility value as an industrial material that has a surface layer reinforcing effect, waterproof performance, hot water resistance and hot water resistance, and can obtain excellent adhesion with finishing materials even if left for a long time after the sealer treatment. It is a thing.

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, microscopic observation of the sealer composition of the present invention revealed a phenomenon unique to the mixed state of the main component, modified PVA having a silyl group in the molecule, and acrylic emulsion. It is not that the particles of acrylic emulsion are uniformly dispersed as islands in the sea of the aqueous solution of silyl group-containing modified PVA, but it is several tens to several hundred times larger than the original particle size. Then, it was found that the pseudo-aggregation occurred. The term “pseudo-aggregation” is used here because when this aggregation state is diluted with water, a particle group is formed that forms a light structure that is dispersed to the order of the original primary particles. .

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. Acrylic emulsion, which is easy to permeate, is a component that forms an extremely large particle group than the pores on the surface of the inorganic plate, so it has little permeation, and a film with a composition rich in acrylic emulsion is formed on the surface layer. it is conceivable that. Moreover, silyl group-containing modification in the coating thickness direction
Since the compositions of both PVA and acrylic emulsion were continuously changing, it seems that the film of the surface layer did not easily peel off from the inorganic plate, and the water blocking performance was exhibited. That is, silyl group-containing modified PVA is a component of the inorganic plate, Si, C
Since there is an interaction that cannot be compared with conventional PVA for compounds such as a, Mg, Al, etc. (Japanese Patent Application No. 58-164604), the permeability to the inorganic plate can be adjusted appropriately, and the result is obtained. The surface reinforcement effect obtained was extremely good. On the other hand, acrylic emulsion is originally a hydrophobic resin, and it is considered that the water resistance of the coating film for the inorganic plate was obtained because the water resistance of the film was good. Moreover, the silyl group-containing modified PVA of the sealer composition of the present invention is mainly used for the large holes on the surface of the inorganic plate.
However, since this modified PVA has a strong interaction with the components of the inorganic plate, it has excellent water resistance at an appropriate depth from the surface layer of the inorganic plate. Since the gel film is formed, the coating solution does not excessively permeate, and accordingly, coating defects are less likely to occur, and it is considered that a better stopping star was obtained.

It is considered that the above-mentioned appropriate permeability to the inorganic plate is not the case, but is due to the degree of pseudo-aggregation obtained by the mixing ratio of the silyl group-containing modified PVA and the acrylic emulsion.

Furthermore, in the present invention, since the waterproofing agent is used in combination,
It is considered that the silyl group-containing modified PVA is made water resistant, and as a result, the hot water resistance and hot water resistance of the sealer coating film are further 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 observing the waterproof performance of a sealer, various porous inorganic plates were coated with the solid content of the composition of the present invention at 20 g / m ²
After drying at 20 ° C. 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 This is 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 topcoat finishing treatment. In the test described in (1), the topcoat finishing treatment is performed. Solvent type acrylic resin paint (Toa Paint Co., Ltd.)
Co., Ltd., acrylic DX for toilet, white) was applied, and before drying, 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
At the same time, 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 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. In a test to check the resistance to such outdoor exposure, the sample treated with the sealer described in (1) was irradiated with a xenon lamp (Shimadzu Corporation, XW-60V ₃ , 6KW) for 200 hours at 40 ° C and every 2 hours. 18
Water was sprayed for minutes, and changes in the surface treated with the sealer were 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 to see the stability of the liquid during coating of the sealer.
Marlon tester (manufactured by Shinsei Sangyo Co., Ltd .: MARON 1000rp
m), a shear force is applied to a 50 g coating liquid at a load of 25 kg and 1000 rpm for 10 minutes, and the amount of the gelled product generated (the gelled product is separated and dried with 100 mesh wire mesh, and the weight% relative to the solid content of the 50 g coating liquid)
Express with. ) Was checked.

(5) Warm 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 150 ° C. for 20 minutes, and then a solvent-type acrylic resin paint (Toa Paint Co., Ltd., for tore tiles) Acrylic DX,
White) was applied and dried at room temperature for 2 days. 50 of this coating
It was immersed in warm water at ℃ for 2 consecutive weeks, and the swelling of the top-coat paint was observed.

(6) Hot 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 and} dried at 150 ° C. for 20 minutes, and then a solvent-based acrylic resin coating (manufactured by 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 vinyltrimethoxysilane 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. Acrylic / styrene copolymer emulsion with a glass transition temperature (Tg) of 85 ° C (manufactured by High Pressure Gas Industry Co., Ltd., Pegal LY508,
To 100 parts of solid content (51%), 85 parts of the above modified PVA 15% aqueous solution was mixed with stirring, and correction water was added to obtain a sealer composition having a concentration of 25%. Use this sealer with a calcareous plate (specific gravity 0.
85, water content 7%)
It is shown in FIG.

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 liquid in which the acrylic-styrene copolymer emulsion used in Example 1 was prepared at 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 2 to 4 and Comparative Examples 7 to 9 The procedure of Example 1 was repeated, except that the acrylic emulsion used in Example 1 was replaced by an acrylic emulsion having Tg as shown in Table 2. The results are shown together in Table 2.

Examples 5 to 8 and Comparative Examples 10 to 11 The procedure of Example 1 was repeated, except that the modified PVA in Example 1 and the acrylic emulsion were mixed in the following weight ratios. The results are shown together in Table-3.

Example 9 0.2 mol% of silyl groups as vinylsilane units, obtained by saponifying a copolymer of vinyltriacetoxysilane and vinyl acetate, and a saponification degree of vinyl acetate units of 98.
Modified PVA containing silyl group in the molecule with 5 mol% and degree of polymerization of 1000
I 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. The results are shown in Table-4.

Examples 10 to 13 and Comparative Examples 12 to 13 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-4. Example 9 was repeated except for using. The results are shown together in Table-4.

Examples 14 to 17 Except that 100 parts of the sealer composition of Example 1 was added with 35 parts of a waterproofing agent shown below (prepared to have a solid content of 20%) to perform the test. I went as well. The results are shown together in Table-5.

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 14 When the hot water resistance test was additionally performed for Example 1. The results are shown in Table-5.

Examples 18 to 22, Comparative Example 15 Same as Example 14 except that the modified PVA and colloidal silica solid content ratios in Example 14 are changed as follows, and the water content of the silica sheet during sealer coating is changed. I went to. The results are shown together in Table-6.

Example 23 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 (extra-dry specific gravity 0.85, water content 7%). It shows in Table-7.

Example 24 A pigmented red sealer composition obtained by adding 0.27 parts of urea, 10 parts of titanium dioxide powder and 0.2 part of red iron oxide to the sealer composition of Example 1 was used as a calcareous plate (specific gravity 0.85, water content 7).
%). The results are shown in Table-7.

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)

(57) [Claims] 1. A silyl group in the molecule (A) is 0.01 to 5 mol%.
A modified polyvinyl alcohol having (B) and (B) an acrylic emulsion having a glass transition temperature of higher than 50 ° C. and lower than 120 ° C. as a main component, and a solid content weight ratio (A) of both.
/ (B) is the range of 5 / 95-50 / 50, The sealer composition for porous inorganic plates characterized by the above-mentioned. 2. (A) 0.01 to 5 mol% silyl group in the molecule
The sealer composition for a porous inorganic plate according to claim 1, wherein the modified polyvinyl alcohol has a saponification product of a copolymer of a vinyl ester and an olefinic unsaturated monomer having a silyl group in the molecule. . 3. (A) 0.01 to 5 mol% silyl group in the molecule
A modified polyvinyl alcohol having (B), an acrylic emulsion having a glass transition temperature of more than 50 ° C. and not more than 120 ° C., and (C) a waterproofing agent of (A) as a main component, and a solid content weight ratio (A) / (B) is 5/95 to 50/50, (A) /
(C) is the range of 99.5 / 0.5-10 / 90, The sealer composition for porous inorganic plates characterized by the above-mentioned.