JPH0525432A - Undercoating material for porous inorganic board - Google Patents

Abstract

PURPOSE:To provide the subject material which is based on polyvinyl alcohol, excellent in water resistance, workability, and handling properties as well as in capability to permeate into and reinforce a porous inorg. board such as a calcium silicate board, an inorg. cement board, etc., and suitable for undercoating the board. CONSTITUTION:The objective material comprises a silylated polyvinyl alcohol, an aq. emulsion of a synthetic polymer such as a polyacrylate, and a polyisocyanate such as a blocked polyisocyanate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base paint for porous inorganic plates. More specifically, the present invention relates to a polyvinyl alcohol-based undercoating material which can be suitably used as an undercoat for building materials and interior materials such as calcium silicate boards and cement inorganic boards, and has excellent penetration reinforcement, water resistance, workability and handleability.

[0002]

2. Description of the Related Art Conventionally, calcium silicate boards and cement-based inorganic boards have been widely used as building interior materials or exterior materials having excellent fire resistance and heat insulation properties. Undercoat paints for these inorganic boards have been widely used. As such, ones having various compositions of organic solvent type and water type are used.

Further, in recent years, in consideration of increasing social concern about environmental problems and risk of fire, etc., an organic solvent-based undercoat paint is being changed. These calcium silicate boards and cement-based inorganic boards are usually manufactured by extrusion molding, press molding, etc. in order to increase production efficiency or improve dimensional stability. Steam curing and autoclave curing are also performed. With the increase in the strength, the surfaces of calcium silicate plates and cement-based inorganic plates tend to become dense, and the water-based undercoating and organic solvent are used depending on the surface properties and the use of the inorganic plates. The reality is that different types of undercoat paints are used properly.

Conventional aqueous undercoat paints have been manufactured by blending an aqueous solution of a water-soluble polymer such as polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) or polyacrylic acid with an emulsion such as an acrylic emulsion. Regarding these manufacturing methods, for example, JP-A-2-219868, JP-A-2-107673, JP-A-62-161878 and JP-A-63-139.
No. 082, No. 63-139083, No. 63-
It is disclosed in Japanese Patent Nos. 139084 and 64-14182.

Other aqueous paints include undercoat paints using water-soluble polyester resins, polyurethane resins, polyolefin resins and the like. In addition, a water-soluble two-component epoxy resin or the like is commercially available or has been developed. further,
As water-soluble emulsion system, polyacrylic acid resin,
Methyl (meth) acrylate resin, vinyl acetate resin, ethylene-vinyl acetate resin, etc. are known.

[0006] At present, PVA is a water-based undercoating material that develops a surface layer reinforcing effect by penetrating from the surface of members such as calcium silicate plate (hereinafter referred to as "calcal plate") and cement inorganic plate to the inside and reacting with inorganic substances. Modified PVA containing a silyl group in the molecule is known. On the other hand, other water-based undercoat paints, such as polyacrylic emulsion and two-pack type epoxy resin, are adhered only by the adhesive force with the surface of the member and impregnated and permeated to develop the surface layer reinforcing effect. Can't expect.

In any case, the undercoating paints so far have not been sufficient in the reinforcing effect and have not been satisfactory in performance such as water resistance. On the other hand, as organic solvent-based undercoat paints, a large number of polyacrylic acid resins, polymethacrylic acid resins, poly (meth) acrylic acid methyl resins, solvent-type epoxy resins, solvent-type polyurethane resins, etc. are commercially available or developed. Since the solvent-type undercoating paint has a low viscosity, it is used for steam curing, autoclave curing products, etc. where the surface of the member is dense, and it exhibits impregnation reinforcement and water resistance. However, the use of these organic solvent-based paints has been withheld due to environmental problems and fire problems, and the demand for undercoat paints is shifting to water-based ones. From this point of view, it is necessary to develop a water-based base coating that penetrates from the surface and has the effect of reinforcing the surface layer of the member, has excellent water resistance, and is easy to work and handle.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, can be easily manufactured, and can penetrate into a surface layer portion of an inorganic substrate such as a calcium silicate plate. Another object of the present invention is to provide a new water-based base coating material which is excellent in surface layer reinforcement, water resistance, workability, and handleability.

[0009]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems. As a result, a composition or mixture comprising the silyl group-modified PVA (a), the synthetic polymer aqueous emulsion (b) and the polyvalent isocyanate compound (c) is used as an excellent porous inorganic plate capable of solving the above problems. We have found that it becomes a base paint. The present invention has been completed based on such findings.

The base coating material according to the present invention includes the above-mentioned (a),
The components (b) and (c) are essential components.
There are various types of silyl group-modified PVA as the component (a), and there is no particular limitation as long as it is a PVA having a silyl group, but normally, the silyl group is 0.01 to 5 mol% in the molecule.
PVA having is preferred. The modified PVA may be a saponified product of a copolymer of vinyl ester and an olefinically unsaturated monomer having a silyl group in the molecule.

The viscosity average degree of polymerization (hereinafter simply referred to as the degree of polymerization) of the modified PVA may be appropriately determined according to various situations and is not particularly limited, but 100
〜4000 is preferable, and 100 to 2,000 is more preferable. When the degree of polymerization is too small, the impregnating property is high, but the adhesive force to the surface of members such as a calcareous plate, a gypsum board, and a cement inorganic plate is small, and the reinforcing effect may not be sufficiently exhibited. On the other hand, if the degree of polymerization is too large, the viscosity will increase and the permeability to the member will decrease, so that a sufficient surface layer reinforcing effect cannot be expected. The silyl group modification degree of PVA is preferably 0.01 to 5 mol% as described above.
~ 2 mol% is more preferred. If the degree of silyl group modification is too low, the amount of silyl groups in the PVA molecule will be small, and as a result, the adhesive force with the surface of the calcareous plate, cement inorganic plate, etc. will be weak, and a sufficient surface layer reinforcing effect will not be exhibited. On the other hand, if the degree of silyl group modification is too high, the solubility in water is lowered and the storage stability is deteriorated, which is not preferable.

Next, the component (b) of the base paint of the present invention is
It is an aqueous emulsion of synthetic polymers. As the synthetic polymer constituting this aqueous emulsion, various kinds can be applied, but preferred are polyacrylic acid ester, polymethacrylic acid ester, polyvinyl acetate, ethylene-vinyl acetate copolymer. , Polyacrylonitrile, polyurethane resin, etc. Moreover, the thing which made the emulsion of the graft polymer which used these as a raw material is also mentioned. For example, as a graft polymer of vinyl acetate, polyvinyl acetate (PVA
c) Macromonomer and methyl methacrylate (MMA)
And a saponified product thereof, a PVAc macromonomer and a polyethylene oxide (PEO) copolymer or a saponified product thereof, and a PVAc macromonomer and a lauryl methacrylate copolymer or a saponified product thereof. And so on. The particle size of the aqueous emulsion is not particularly limited, but is 0.0
It is preferably 5 to 100 μm, more preferably 1 to 5 μm. When the particle size of the aqueous emulsion is too small, the aqueous emulsion does not remain on the surface of the member when applied to the member, and the mixture of the silyl group-containing PVA and the aqueous emulsion is present on the member surface, so the adhesion tends to deteriorate. It is in. On the other hand, when the particle diameter of the aqueous emulsion is within the above range, the aqueous emulsion is retained on the surface of the member and impregnated with the silyl group-modified PVA to strengthen the reinforcing effect.
On the other hand, if the particle size of the aqueous emulsion is too large, the yield of the aqueous emulsion on the surface of the member is very good, but the film-forming property is deteriorated, which is not preferable.

The glass transition temperature (Tg) of the synthetic polymer constituting the aqueous emulsion which is the component (b) differs depending on the particle size of the emulsion and other conditions and cannot be uniquely determined, but it is 5 to 120. The thing of the range of (degreeC) is preferable, and that of 15-60 degreeC is more preferable. Tg
When the value is too low, the surface layer reinforcing effect of the emulsion is small when the water content of the calcareous plate or the inorganic plate is high and it is necessary to dry at high temperature. On the other hand, if the Tg is too high, high temperature drying of a usual inorganic plate coating line will result in poor film formation and a decrease in waterproofness, which is not preferable. The emulsifier of the above aqueous emulsion may not have ionicity, but as the ionicity, nonionic or anionic type is usually preferable.

Further, the component (c) of the base coating material of the present invention is a polyvalent isocyanate compound. Here, the polyvalent isocyanate compound is, for example, tolylene diisocyanate (TDI); hydrogenated TDI; trimethylolpropane-TDI adduct (for example, Bayer, trade name: De
smodur L); triphenylmethane triisocyanate; methylenebisdiphenylisocyanate (MD
I); hydrogenated MDI; polymerized MDI; hexamethylene diisocyanate; xylylene diisocyanate; 4,4-
Dicyclohexylmethane diisocyanate; isocyanates such as isophorone diisocyanate and blocked products thereof. Of these, blocked polyisocyanates are preferred. In addition, a prepolymer obtained by polymerizing a polyol in advance with an excess of polyisocyanate may have an isocyanate group as an end group. It is also possible to use so-called blocked isocyanates shielded with phenol, oxime, ethyleneimine and the like. Further, together with the polyvalent isocyanate compound, a metal salt,
It is also possible to use a polyvalent aldehyde, polyamide epichlorohydrin, etc. together. This metal salt has an atomic weight of 2
Salts of 6 or more metals, such as aluminum, chromium, iron,
Chlorides such as zirconium and tin and nitrates are preferable. As the polyvalent aldehyde, those typified by glyoxal and adipinedialdehyde are preferable. As the polyamide epichlorohydrin, a water-soluble resin obtained by quaternizing a polyamide synthesized from adipic acid and diethylenetriamine with epichlorohydrin is preferable.

The polyisocyanate compound as the above-mentioned component (c) acts as a so-called waterproofing agent,
In addition, colloidal silica, water glass, borax, epoxy resin, polyamide resin, melamine resin, polyamide methylol resin, polyethyleneimine, etc. can be used together. Of these, colloidal silica is preferable. Addition of this colloidal silica can significantly improve the water resistance. The addition amount is not particularly limited, but generally 10 to 100 relative to the total amount of the component (a) or the components (a) and (b) in terms of solid content.
It may be added in the range of wt% as a guide. If the amount added is too small, the water resistance is insufficiently improved, and if it is too large, the penetrability of the base coating material into the member is deteriorated and the surface layer reinforcing effect is reduced, and at the same time the water resistance is reduced.

The base paint of the present invention is composed of the components (a), (b) and (c) as described above, but the mixing ratio thereof is not particularly limited, and the mixing component, purpose of use and use. It may be appropriately selected according to the conditions and the like. However, the preferable mixing ratio is (a) component / (b) component = 1/99 to 90/10 (weight ratio), and particularly preferably (a) component / (b) component = 10/90 to 50. / 5
It is 0 (weight ratio). Also, (a) component / (c) component =
The ratio is preferably 99/1 to 80/20 (weight ratio), more preferably (a) component / (c) component = 95/5 to 90/10 (weight ratio).

The base coating material of the present invention is a calcareous board produced by a papermaking method, a calcareous board produced by extrusion molding, a cement inorganic board, or an inorganic board obtained by steam-curing or autoclaving the above-mentioned inorganic board, particularly a porous inorganic board. It is useful as an undercoat paint.

Further, in order to produce the base coating material of the present invention, the components (a), (b) and (c) may be blended as essential components as described above, and the blending order and blending method are not particularly limited. A conventional method may be used. As a preferable method, first, the silyl group-modified PVA as the component (a) is heated and dissolved by stirring, and then the aqueous emulsion as the component (b) is sequentially added and dissolved while stirring, and then the component (c) is added. A method of mixing a certain polyvalent isocyanate compound can be mentioned. In particular, the (c) polyvalent isocyanate compound that functions as a water resistance agent is
It is preferable to mix just before applying the base paint. In addition to the components (a), (b) and (c) described above, the base coating material of the present invention may be used as an inorganic pigment such as calcium carbonate, clay, titanium oxide, zinc oxide, red iron oxide, or as a stabilizer for coating liquid. It is also possible to disperse and mix the urea and the defoaming agent. Further, it may be diluted with water at the end so as to obtain a coating solution having an appropriate viscosity.

When the undercoating material of the present invention is used as an undercoating material for a porous inorganic plate, the concentration of the coating solution varies depending on various circumstances, but is generally 10 to 50% (solid content concentration), preferably It is applied at 20 to 40% (solid content concentration). The base coating material of the present invention is preferably used as a base coating material for a porous inorganic plate. The porous inorganic plate to be applied here is a cement type, calcium silicate type, gypsum type, sand, clay mineral type. It is a plate-shaped body whose main component is an inorganic material such as, and specifically, lightweight concrete, precast concrete, lightweight cellular concrete (AL
C), mortar, calcium silicate board, pulp cement board, gypsum board, hard board, etc., and organic components are also included, but all of them are mainly composed of inorganic components such as compounds of Si, Ca, Mg and Al. It will be. The method of applying to the inorganic board is spray coating, roller coating,
A general coating method such as a flow coater is possible. The coating amount is usually preferably selected in the range of 0.5 to 100 g / m ² . Note that the effects of the present invention are more remarkably exhibited when dried by heating at 100 ° C. or higher.

[0020]

EXAMPLES Next, the present invention will be explained more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In Examples and Comparative Examples, parts and% mean parts by weight and% by weight, respectively, unless otherwise specified. Moreover, the test method in an Example is as follows.

(Water permeability test) In a test for observing the water-stopping performance of a sealer (base paint), various porous inorganic plates were coated with the coating composition of the present invention at a solid content of 20 g / m ² at 100 ° 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 epoxy resin so as not to leak water, connect a burette to the end, add water so that the initial water head is 25 cm, and decrease the amount of water after 8 hours. Read The smaller the value, the better the waterproof performance. (Adhesion test) In a test for observing the surface layer reinforcing effect of the porous inorganic plate by the base paint and the adhesion between the inorganic plate surface layer and the topcoat paint, as a topcoat paint to the test body described in the above water permeability test, a solvent A type acrylic resin paint (Acrylic DX for Toa Tile, white, manufactured by Toa Paint Co., Ltd.) was applied, and before it was dried, a cotton cloth was placed on it and dried at room temperature for 2 days. After that, a cut was made in a width of 1 cm with a knife, the peeling resistance was measured with an autograph (Shimadzu Corporation, IM-100 type) at a peeling angle of 90 degrees, and a pulling speed of 50 mm / min, and the peeled state was observed. That is, those having poor adhesion to the topcoat paint are peeled off at the interface between the undercoat paint application 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. (Weathering test) Inorganic plates such as building materials may be left for several months or more after the base paint is applied and before the cosmetic finish. In this case, the inorganic plate coated with the undercoat used for construction is exposed to sunlight, rain, and snow. Due to such exposure, if the surface of the base paint is roughened or discolored, the cosmetic finish is impaired. Also, the adhesiveness with the decorative finish changes. In such a test for observing resistance to outdoor exposure, a sample treated with the undercoat paint described in the above water permeability test was subjected to a xenon lamp at 40 ° C. (Shimadzu Corporation, XW-6.
0V ₃ , 5KW) 200 hours irradiation and every 2 hours 18
Water was sprayed for minutes and changes in the surface of the undercoat paint were examined. (Marlon mechanical stability test) This is a test to check the stability of the liquid during the application of the base paint, and is 50 g using a Marlon tester (MARON, 1000 rpm, manufactured by Shinsei Sangyo Co., Ltd.)
A shearing force was applied to the coating solution of No. 1 under a load of 25 kg at 1000 rpm for 10 minutes to check the amount of gelled product generated (the gelled product was separated and dried with 100 mesh wire netting, and expressed in weight% relative to the solid content of 50 g of the coating solution). . (Hot water resistance test) The base paint 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 (manufactured by Toa Paint Co., Ltd.,
Acrylic DX for toilet, white) was applied and dried at room temperature for 2 days. This coated product was continuously immersed in warm water at 50 ° C. for 2 weeks, and swelling of the top coating composition was observed. (Heat resistance test) A base inorganic coating material 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 coating material (manufactured by Toa Paint Co., Ltd.,
Acrylic DX for toilet, white) was applied 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 PVA modified with silyl group (manufactured by Kuraray Co., Ltd., trade name: R-2)
105, polymerization degree 550, saponification degree 98.5 mol%, silyl group 0.5 mol modified 45% 10% aqueous solution, acrylic emulsion (polyacrylic acid methyl ester, Tg40)
℃, average particle size 110 nm, solid content concentration 50%) 55 parts,
Antifoaming agent 0.2 parts, blocked polyisocyanate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Elastron BN-69) 4.
Put 5 parts in a dissolution tank and stir-mix at room temperature to obtain a concentration of 23%.
The base paint of The base paint was applied to a calcareous plate (absolute dry specific gravity 1.1, water content 8%) to evaluate the performance. The results are shown in Table 1.

As is clear from the comparison with the comparative example in Table 1, the undercoating material of the present invention has no coating defects, water-proof performance,
It can be seen that the surface layer reinforcing effect and the adhesiveness with the topcoat paint (direct and application after the weathering test) are excellent.

Comparative Examples 1 to 6 The performance was evaluated by coating in the same manner as in Example 1 except that the following base coating material was used in place of the base coating material of Example 1. The results are shown together in Table 1. Comparative Example 1: Only PVA Aqueous Solution Used in Example 1 Comparative Example 2: 2 Acrylic Emulsion Used in Example 1
Liquid adjusted to 5% Comparative Example 3: Silyl group-modified PVA used in Example 2 described later
Aqueous solution only Comparative Example 4: Silyl group-modified PVA used in Example 3 described later
Vinyl acetate emulsion (25% liquid) obtained by using as an emulsion stabilizer Comparative Example 5: Existing solvent type urethane sealer (manufactured by Toa Paint Co., Ltd., trade name: Asbestos Sealer # 20) Comparative Example 6: Base When not applying paint

Example 2 PVA modified with silyl group (manufactured by Kuraray Co., Ltd., trade name: R-2)
130, degree of polymerization 1750, degree of saponification 98.5 mol%, silyl group modification 0.6 mol%) 40 parts, acrylic emulsion similar to Example 1 54.8 parts, antifoaming agent 0.2 parts, blocked poly 4 parts of isocyanate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Elastron E-37) was put into a dissolution tank, and Example 1 was added.
The base paint was obtained by stirring and mixing under the same conditions as described above. The same performance evaluation as in Example 1 was performed. The evaluation results are shown in Table 1.

Example 3 PVA modified with silyl group (manufactured by Kuraray Co., Ltd., trade name: R-1)
130, polymerization degree 1750, saponification degree 98.6 mol%, silyl group-modified 0.2 mol%) 50% 10% aqueous solution, Example 1
The same acrylic emulsion (Tg 40 ° C., average particle size 110 nm) 44.8 parts, antifoaming agent 0.2 parts and blocked polyisocyanate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name:
5 parts of Elastron BN-44) was put into a dissolution tank and stirred to obtain a base coating material. This base paint was applied to a Caikal plate (extra-dry specific gravity of 1.0, water content of 8.0%) to evaluate the performance.
The results are shown in Table 1.

Example 4 PVA modified with silyl group (polymerization degree: 250, saponification degree: 88.7)
%, 0.5 mol% silyl group modified) 10% aqueous solution 50 parts,
The same acrylic emulsion as in Example 1 44.8 parts, antifoaming agent 0.2 parts and blocked polyisocyanate (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Elastron BN-69) 5
Parts and a curing agent (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Elastron Catalyst 64), 0.5 parts were put into a dissolution tank,
A base paint was obtained by stirring in the same manner as in Example 1. The same performance evaluation as in Example 1 was performed on this base paint. The evaluation results are shown in Table 1.

Example 5 A base coating material was obtained in the same manner as in Example 4 except that the silyl group of the silyl group-modified PVA was changed to 0.8 mol%. The same performance evaluation as in Example 1 was performed on this base paint. The evaluation results are shown in Table 1.

Example 6 Example 1 except that 2 parts of the same elastron catalyst 64 used in Example 4 were added to the formulation of Example 1.
A base paint was obtained in the same manner as. The evaluation results are shown in Table 1.

Example 7 A base coating composition was obtained in the same manner as in Example 1 except that 10 parts of colloidal silica was added to the composition of Example 1. The evaluation results are shown in Table 1.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

As shown in Table 1, the undercoating material of the present invention has no coating defects, water-stopping ability, surface layer reinforcing effect and adhesion to the topcoating material (immediately and after the weathering test).
Is excellent.

Examples 8-10 Instead of the acrylic emulsion used in Example 1, the second
The performance was evaluated in the same manner as in Example 1 using an acrylic emulsion having Tg as shown in the table. Second result
Shown in the table.

[0037]

[Table 5]

[0038]

[Table 6]

Examples 11 to 13 Instead of the acrylic emulsion used in Example 1, a third
The performance was evaluated in the same manner as in Example 1 using the aqueous emulsions shown in the table. The results are shown in Table 3.

[0040]

[Table 7]

[0041]

[Table 8]

[0042]

INDUSTRIAL APPLICABILITY As described above, the coating material of the present invention is particularly useful as a base coating material for a porous inorganic plate, has good workability and handleability, and is extremely excellent in permeation reinforcing property, water resistance and the like. It is excellent. Therefore, the coating material of the present invention is expected to be effectively and widely used as a base coating material for various porous inorganic plates.

Claims (1)

Claims: 1. A base coating material for a porous inorganic plate, which comprises a silyl group-modified polyvinyl alcohol (a), an aqueous emulsion of a synthetic polymer (b), and a polyvalent isocyanate compound (c).