JPH0575003B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention enables painting before curing in the production of ceramic building materials, and also enables curing of the inorganic base material and drying of the paint film at the same time by high-temperature, high-pressure steam curing. This invention relates to a coating material for ceramic building materials that has excellent appearance and coating performance and can be cured in an autoclave. In this specification, ceramic building materials refer to roofing and wall materials mainly made of inorganic materials such as cement, calcium silicate, gypsum, and asbestos. As a roofing material,
As wall materials such as thick slate and asbestos cement board,
Asbestos calcium silicate board, magnesium carbonate board,
There are asbestos cement boards, ALC boards, etc. [Technical background] In recent years, the industrialization (prefabrication) of residential building materials has shown remarkable growth, and industrialized building materials are lightweight,
Increased strength, productivity improvement, and labor saving are being pursued more and more. On the other hand, in terms of the cosmetic properties of industrialized building materials, designs are becoming more complex and sophisticated, and in terms of functionality, demands for durability, livability, etc. are becoming even stronger. For this reason, ceramic building materials are under pressure to improve productivity, including cost, and durability, including coatings. [Prior art and problems] For the purpose of aesthetics and protection, ceramic building materials have traditionally been coated with colored paint on the surface of an inorganic base material molded product that has been cured and cured and then dried, or colored cement is applied to the surface immediately after the inorganic base material is molded. A method is used in which a slurry is applied, cured and then a transparent paint or colored paint is applied and dried. Ceramic building materials obtained by these methods are coated after the inorganic base material molded product or colored cement slurry has cured and hardened, so the adhesion may be insufficient, and after long-term use, there may be a decrease in gloss, discoloration, or There were shortcomings in weather resistance such as the occurrence of cracks. Furthermore, there were problems with production costs and speed. Therefore, after molding the inorganic base material, we immediately applied colored paint, colored cement slurry, then transparent paint, applied a composite coating material of colored cement slurry and synthetic resin emulsion, and cured and dried. It was proposed to shorten the production process, reduce costs, and improve the performance of the coating by painting it before curing. However, ceramic building materials obtained by these methods have problems with the wet film-forming properties of the synthetic resin emulsion due to painting before curing, and deterioration of the paint film due to alkaline content generated during curing, and the expected adhesion is difficult. The consistency of the paint film is poor, and primary efflorescence occurs on the surface.
It is not possible to overcome these shortcomings by simply focusing on the coating method, such as the occurrence of deterioration or cracking after long-term use, and it is also necessary to pay attention to the composition of the synthetic resin emulsion used as the binder. Ta. On the other hand, as there is a growing demand for lighter weight and higher strength ceramic building materials, studies are underway on curing methods that incorporate high-temperature, high-pressure steam curing (autoclave curing) into the production process, and general-purpose acrylic emulsion However, the wet film forming properties and primary efflorescence prevention properties are poor, and the alkali deterioration of the coating film is significantly accelerated by heating, so it is said that it is impossible to apply the coating before autoclave curing. For example, there is JP-A-57-71884 which allows painting of uncured cement surfaces including autoclave curing, but autoclave curing is not illustrated at all in the examples. As described above, a synthetic resin emulsion that enables painting before curing, including autoclave curing, has not been specifically disclosed. [Object of the invention] The present invention has excellent mixing stability of inorganic admixtures (cement, aggregate, etc.), wet film-forming properties, primary and secondary efflorescence prevention properties, uniform color development, etc. Painting is possible, and autoclave curing allows
To provide an autoclave-curable coating material for ceramic building materials, which simultaneously cures an inorganic base material and dries the coating film, thereby imparting excellent coating appearance and coating performance. [Structure of the Invention] The present invention solves the above-mentioned problems in the production of ceramic building materials, and provides a synthetic resin that is coated before curing, undergoes primary curing by natural curing or steam curing, and then enables autoclave curing. As a result of extensive research into emulsions, we have discovered that through multi-step sequential emulsion polymerization, we have created a continuous polymer particle that contains a specific proportion of unsaturated carboxylic acid on the surface of the relatively hard polymer particle that controls the physical properties of the coating film. The present invention has been completed by discovering that a synthetic resin emulsion having a specific composition and structure, which is coated with a relatively soft polymer that dominates the pores, and whose surface is cross-linked with high density, can fully achieve the objective. That is, the present invention provides (A) an alkyl (meth)acrylate whose alkyl group has 1 to 8 carbon atoms as a main component as a first-stage polymerization component, and which is obtained by copolymerizing a first-stage monomer component. Monomer mixture (B) consisting of a copolymer with a theoretical glass transition temperature of 0° C. or higher; the second stage polymerization component is an alkyl (meth)acrylate whose alkyl group has 1 to 8 carbon atoms; 3-10% by weight of the step monomer component
A monomer mixture containing as an essential component an unsaturated carboxylic acid, and the theoretical glass transition temperature of the copolymer obtained by copolymerizing the second stage monomer component is 20°C or less (C) 3rd As step polymerization components, each step polymerization component comprises a hydrophobic polyfunctional monomer having two or more double bonds in one molecule and an unsaturated monomer containing a hydrolyzable silyl group in the entire polymer. (A) is 60～
80% by weight, (B) 15-35% by weight, (C) 5-15% by weight
The first and second stages are sequentially emulsion polymerized at a ratio of In addition to overlapping some of the
In the presence of the emulsion in which the polymerization rate of the first and second stage polymerization components has reached 90% by weight or more, the second and third stage polymerization components are
An autoclave-curable ceramic building material comprising a multi-step sequential emulsion polymerization emulsion obtained by partially overlapping the steps and having a structure in which the surface of the second-stage polymerization layer is cross-linked with high density. It is a painted material. The synthetic resin emulsion particles of the present invention contain a first-stage polymerization component forming a core layer that is effective for autoclave resistance and durability of a coating film, and an inorganic mixture stability, wet film-forming property, and prevention of primary efflorescence. It is composed of a second stage polymerization component which forms a shell layer which has an effect on properties, and a third stage polymerization component which forms a crosslinking part to promote the mutual effect between the core layer and the shell layer. In the present invention, in order to fully bring out the characteristics of the first and second stage copolymers, the theoretical glass transition temperature of the copolymer obtained by copolymerizing the first stage monomer components is 0. The monomer components are used in such a proportion that the theoretical glass transition temperature of the copolymer obtained by copolymerizing the second stage monomer component is 20°C or less. If the former is below 0℃, the coating film will soften significantly during autoclave curing and the appearance of the coating will deteriorate; if the latter exceeds 20℃, the wet film forming property will be poor.
This is not preferable because it deteriorates the primary efflorescence prevention property. Note that the theoretical glass transition temperature (Tg) of the copolymer obtained by copolymerizing the monomers used here is calculated by the following formula. 1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ +...+Wn/Tgn [However, Tg ₁ , Tg ₂ ,...Tgn is 1, 2,...n The glass transition temperature (K°) of the homopolymer of each component ), W ₁ ,
W ₂ ,...Wn is the weight fraction of each component of 1, 2,...n] Also, the proportion of each stage of polymerization in the entire polymer is (A)
60-80% by weight, (B) 15-35% by weight, (C) 5-15%
Used in percentage by weight. The first layer forming the core layer
If the stepwise polymerization component (A) is less than 60% by weight, paint film deterioration (paint whitening, softening and swelling, loss of gloss) will occur during autoclave curing, whereas if (A) exceeds 80% by weight, inorganic substances including cement will occur. This is not preferable because the mixing stability of the admixture deteriorates. It also forms a shell layer.
If (B) exceeds 15 to 35% by weight, the desired coating film appearance and coating performance will not be achieved. Furthermore, if the third stage polymerization component (C) is less than 5% by weight, mixing stability will be poor, resulting in poor coating performance such as autoclave resistance, adhesion, and water resistance, and if it exceeds 15% by weight, alkaline swelling of the shell layer will occur. Since the properties are significantly inhibited, the continuity becomes poor and primary efflorescence is likely to occur on the surface of the coating film, which also causes cracks in the coating film. Furthermore, unreacted double bonds remain, and coagulation is likely to occur accompanied by side reactions such as hydrolysis-condensation reactions, which is undesirable. Examples of the alkyl (meth)acrylates in which the alkyl group has 1 to 8 carbon atoms to be used in the first and second stage polymerization components of the present invention include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and propyl (meth)acrylate. ) acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate
Acrylate, amyl(meth)acrylate, hexyl(meth)acrylate, octyl(meth)acrylate
There are acrylates, 2-ethylhexyl (meth)acrylates, etc., and one type or a mixture of two or more types selected from these groups may be used. Most preferred are 2-ethylhexyl acrylate and methyl methacrylate. Note that throughout this specification, "(meth)acrylate" means "acrylate" or "methacrylate." Alkyl (meth)acrylates directly affect autoclave resistance and coating performance, and are selected depending on the desired physical properties. Alkyl (meth)acrylates whose alkyl group has more than 8 carbon atoms solidify during emulsion polymerization. It is unsuitable because it generates substances and the polymerization reaction deteriorates significantly. Furthermore, in some cases, aromatic vinyls such as styrene, vinyl esters such as vinyl versatate, amides of αβ unsaturated mono- or dicarboxylic acids, N-methylolamides, glycidyl esters, ethylene glycol esters, etc. May be used in combination. These are used to replace a part of the alkyl (meth)acrylate and improve coating film performance.The amount is preferably less than 40% by weight of the entire polymer, and if used in excess of 40% by weight, polymerization reaction will occur. properties may deteriorate, and a large amount of unreacted monomer may remain.
The emulsion thickens and becomes a gel. Moreover, it is not preferable because the durability of the coating film decreases. In the present invention, the second stage polymerization component contains an unsaturated carboxylic acid as an essential component in an amount of 3 to 10% by weight of the second stage monomer component. Examples of the unsaturated carboxylic acid include methacrylic acid, acrylic acid, crotonic acid, itaconic acid, maleic acid, etc., and one type or a mixture of two or more types selected from these groups may be used. Most preferred is methacrylic acid. The unsaturated carboxylic acid necessary for the second stage polymerization component contributes to the alkali swelling property of the shell layer and improves the wet film-forming property of the polymer _particles . It has the effect of preventing primary efflorescence that precipitates on the surface due to the movement of moisture immediately after painting or during curing and drying, and the effect of improving the mixing stability of inorganic admixtures. If this amount is less than 3% by weight, the primary efflorescence prevention property and mixing stability will be poor, and if it exceeds 10% by weight, the mixing stability will be poor, and 2
It is not preferred because it causes secondary efflorescence. Hydrophobic polyfunctional monomers having two or more double bonds in one molecule (hereinafter simply referred to as polyfunctional monomers) used as the third-stage polymerization component of the present invention include, for example, ethylene Glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)
Acrylate, 1.6 hexanediol di(meth)
Acrylate, Tetraethylene glycol di(meth)acrylate, 1.3butanediol di(meth)
Examples include acrylate, neopentyl glycol di(meth)acrylate, divinylbenzene, and allyl(meth)acrylate, and one or more selected from these groups may be used in combination. Most preferred are ethylene glycol dimethacrylate and divinylbenzene. It is important that the polyfunctional monomer is hydrophobic, and a sea-island structure of highly cross-linked parts is created on the surface of the shell layer formed by the second-stage polymerization component, and even though the content is large, the core layer There is a synergistic effect between the coating performance of the coating film and the film forming property of the shell layer, and significant improvements in inorganic mixing stability, autoclave resistance, and coating performance are observed. When used in combination with a hydrophilic polyfunctional monomer or a hydrophilic monomer, the monomer is uniformly distributed on the surface of the second stage polymerization layer to form a third stage polymerization layer on the particle surface. The desired coating film appearance and coating performance cannot be obtained. In addition, examples of unsaturated monomers containing a hydrolyzable silyl group (hereinafter simply referred to as organosilicon monomers) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and acetoxysilane,
Vinylpropoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc., and one type selected from these groups or a mixture of two or more types are used. You may. Most preferred is γ-methacryloxypropyltrimethoxysilane. It is essential to use organosilicon monomers as a third-stage polymerization component in combination with polyfunctional monomers, which improves autoclave resistance, coating film adhesion,
It is particularly effective in improving adhesion after water resistance and freeze-thaw tests. If this monomer is used alone, the stability of the inorganic admixture and the prevention of primary efflorescence will be significantly deteriorated, and cracks will occur in the coating film, which is not preferable. In the present invention, in order to produce a multistage sequential emulsion polymerization emulsion, the first stage polymerization components are continuously added and added dropwise in portions to carry out emulsion copolymerization using a conventionally known method. Examples of emulsifiers used in this case include nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyethylene oxide polypropylene oxide block copolymer, and polyoxyethylene sorbitan ester, or higher alcohol sulfuric esters. Anionic surfactants such as sodium alkylbenzine sulfonate, sodium dialkyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate are used, and reactive surfactants such as sodium allyl alkyl sulfosuccinate are used. It is more preferable to use an agent in terms of water resistance and adhesion. As a polymerization initiator, for example, persulfates such as ammonium persulfate, sodium persulfate, and sodium persulfate, hydrogen peroxide, etc. are used, and if necessary, redox catalysts such as sodium bisulfite, ascorbic acid, and sodium thiosulfate are used. Using a buffer such as sodium bicarbonate, ammonium carbonate, or disodium phosphate, emulsion copolymerization is carried out at a polymerization temperature of 50°C to 95°C until the polymerization rate of the first stage polymerization component is 90% by weight or more. At this time, if the polymerization rate is less than 90% by weight, the appearance of the coating film will be poor and the desired coating performance will not be obtained. Subsequently, polymerization of the second stage polymerization components is started in the presence of the emulsion, and the first stage and second stage polymerization are carried out in exactly the same manner as the first stage emulsion polymerization.
Emulsion copolymerization is carried out until the polymerization rate of the step polymerization components is 90% by weight or more. At this time, if the polymerization rate is less than 90% by weight, the film forming properties of the shell layer and the coating performance of the core layer cannot be obtained. Subsequently, polymerization of the third stage polymerization component is initiated in the presence of the emulsion, and emulsion polymerization is carried out in the same manner. In this way, each stage is sequentially emulsion polymerized in the presence of the polymer emulsion formed before the emulsion copolymerization is completed, and the first stage and the second stage, and the second stage and the third stage are formed. A multi-stage sequential emulsion polymerization emulsion is obtained, which has a structure in which the surface of the second stage polymerization layer is crosslinked with high density. In this case, it is necessary to conduct the polymerization without adding new surfactant from the second stage polymerization onwards in order to overlap the surface of the polymer particles at each stage without creating new polymer particles. Furthermore, if the polymerizable radicals have completely disappeared, it is necessary to newly start the polymerization reaction by adding a polymerization initiator. That is, in the second step, a relatively large amount of hydrophilic unsaturated carboxylic acid is coated on the surface layer, and in the third step, only a hydrophobic crosslinkable monomer is used to crosslink the surface with high density to form a polymer. A feature of the present invention is an acrylic emulsion in which the particle surface has a heterogeneous structure. [Effects of the Invention] The autoclave-curable coating material for ceramic building materials of the present invention has excellent mixing stability of inorganic admixtures, wet film forming properties, primary and secondary efflorescence prevention properties, and uniform color development. As a colored paint, transparent paint, and cement-emulsion composite coating material, it is possible to paint ceramic building materials before curing, and autoclave curing allows drying of the curing coating on inorganic base materials at the same time. can be used to create lightweight, high-strength ceramic building materials. The coating film created in this way has excellent durability such as adhesion, freeze-thaw resistance, and weather resistance, and is effective in strengthening the surface layer of ceramic building materials and improving their fragility. At the same time, it functions not only as a sealer but also as a top coat, and is also effective as a thick film paint that does not require a sealer. [Examples and Comparative Examples] Next, the present invention will be specifically explained, but it is not limited to these Examples. It should be noted that all percentages in the description represent percentages by weight, and parts represent parts by weight. Example 1 200 parts of deionized water and 2 polyoxyethylene octyl phenol ether surfactants were placed in a separable flask (1) equipped with a stirring bar, thermometer, monomer dropping funnel, nitrogen gas introduction tube, and cooling tube.
1 part, 0.2 part of sodium polyoxyethylene lauryl ether sulfate (20% of the total amount of surfactant), and 1 part of sodium bicarbonate, and the temperature was raised to 75°C in a water bath while purging with nitrogen. Next, as the first step, the first step monomer mixture shown in 1.
5% of ammonium persulfate aqueous solution
The polymerization reaction was carried out for 30 minutes. While controlling the internal temperature to 78-80℃, add the remaining 90% of the first stage monomer mixture for 3 hours.
At the same time, 5 parts of 10% ammonium persulfate was continuously added over 4 hours and 20 minutes, and the remaining surfactant (80% of the total amount) was continuously added over 2 hours and 30 minutes to advance the polymerization reaction. After the first step monomer mixture was added dropwise (at this point, the polymerization rate was 98%), the second step monomer mixture shown in the table was continuously added dropwise for 50 minutes as the second step. The polymerization reaction was allowed to proceed. After the second step monomer mixture was added dropwise (at this point, the polymerization rate was 98%), the third step monomer mixture shown in the table was continuously added dropwise for 20 minutes to polymerize. The reaction was carried out. After the addition, the internal temperature was raised to 85℃, and the temperature was maintained for another 2 hours to ripen. After cooling to room temperature, the pH was adjusted to 8.5 with aqueous ammonia.
A stable synthetic resin emulsion was obtained by filtration through a mesh wire mesh. Examples 2 to 5 According to the emulsion manufacturing method described in Example 1, the monomer mixture at each stage was shown in Table 1,
A stable synthetic resin emulsion was obtained. Example 6 According to the emulsion manufacturing method described in Example 1, the monomer mixture at each stage was shown in Table 1,
A stable synthetic resin emulsion was obtained by continuously dropping the first stage monomer mixture over 2 hours and 40 minutes and the second stage monomer mixture over 1 hour and 20 minutes. Comparative Examples 1 and 2 200 parts of deionized water, surfactant polyoxyethylene octyl phenol ether 2 were placed in a separable flask (1) equipped with a stirring bar, thermometer, monomer dropping funnel, nitrogen gas introduction tube, and cooling tube.
1 part, 0.2 part of sodium polyoxyethylene lauryl ether sulfate (20% of the total amount), and 1 part of sodium bicarbonate were added, and the temperature was raised to 75°C in a water bath while purging with nitrogen. Next, as the first stage, 10% of the total amount of the first stage monomer mixture shown in
%, 5 parts of 10 ammonium persulfate aqueous solution was added to start polymerization, and the charging polymerization reaction was carried out for 30 minutes. While controlling the internal temperature to 78-80℃,
Remaining first stage weight monomer mixture 90% and 10%
5 parts of an aqueous ammonium persulfate solution was continuously added dropwise over 4 hours, and at the same time, the remaining surfactant (80% of the total amount) was added over 3 hours and 30 minutes to carry out a polymerization reaction. After the first stage polymerization monomer mixture was added dropwise, the internal temperature was raised to 85°C, and after aging while maintaining the temperature for another 2 hours, it was cooled to room temperature and adjusted to pH 8.5 with aqueous ammonia. , and filtered through a 100-mesh wire mesh to obtain a synthetic resin emulsion. Comparative Examples 3 to 8 According to the emulsion manufacturing method described in Example 1, the monomer mixture at each stage was shown in Table 1,
A synthetic resin emulsion was obtained. Comparative Example 9 According to the emulsion manufacturing method described in Example 1, the monomer mixtures for each stage of polymerization were shown in Table 1, and the first stage monomer mixture was continuously added dropwise over 2 hours and 10 minutes. Remaining surfactant (total amount
80%) was continuously added over a period of 2 hours, followed by continuous dropwise addition of the second stage monomer mixture over a period of 1 hour and 50 minutes to obtain a synthetic resin emulsion. Comparative Example 10 According to the emulsion manufacturing method described in Example 1, the monomer mixture of each stage was shown in Table 1, and the first stage monomer mixture was continuously added dropwise over 2 hours and 10 minutes, and at the same time the remaining monomer mixture was added dropwise. surfactant (80% of total amount)
was continuously added over 2 hours, followed by continuous dropwise addition of the second stage monomer mixture over 1 hour and 30 minutes, and then continuous dropwise addition of the third stage monomer mixture for 40 minutes to form a synthetic resin emulsion. Obtained. Comparative Example 11 200 parts of deionized water, surfactant polyoxyethylene octyl phenol ether 2 were placed in a separable flask (1) equipped with a stirring bar, thermometer, monomer dropping funnel, nitrogen gas introduction tube, and cooling tube.
1 part, 0.2 part of sodium polyoxyethylene lauryl ether sulfate (20% of the total amount), and 1 part of sodium bicarbonate were added, and the temperature was raised to 75°C in a water bath while purging with nitrogen. Next, as the first step, 10% of the total amount of the first step monomer mixture shown in No. 1 was charged, 5 parts of 10 ammonium persulfate aqueous solution was added to start polymerization, and the charging polymerization reaction was carried out for 30 minutes. While controlling the internal temperature to 78-80℃ and adding 10% of the first stage monomer mixture in portions every 25 minutes, at the same time 5 parts of a 10% ammonium persulfate aqueous solution was added for 4 hours and the remaining surfactant. (80% of the total amount) was continuously added over 2 hours and 30 minutes to advance the polymerization. After the final addition of the first-stage monomer mixture (at this point, the polymerization rate was 89%), 50% of the second-stage monomer mixture shown in the table was added as a second stage. After 25 minutes, the remaining 50% was added to allow the polymerization reaction to proceed. After the addition of the second stage monomer mixture (at this point the polymerization rate was 87%),
Subsequently, as a third step, the third step monomer mixture shown in the same table was continuously added dropwise for 20 minutes to carry out a polymerization reaction. After dropping, raise the internal temperature to 85℃, and then
After aging while maintaining the temperature, cool to room temperature and adjust the pH to 8.5 with ammonia water.
It was filtered through a 100-mesh wire mesh to obtain a synthetic resin emulsion. Coating Film Test Using the synthetic resin emulsions obtained in Examples and Comparative Examples, A and B were dispersed and mixed using a stirrer according to the following formulation to obtain a cement-emulsion composite coating material. 100 parts of Portland cement, 200 parts of No. 8 silica sand,
Place mortar paste containing 95 parts of water on the mold, 100Ks/
Apply a coating material of 200μ (dry film thickness) with a spray gun to the surface of the mortar molded plate immediately after pressure molding at cm ² , leave it to dry at room temperature for 1 hour, then dry at a temperature of 60℃ and humidity.
Steam curing was carried out for 8 hours in an atmosphere of 80% RH, and further autoclave curing was carried out for 8 hours in saturated steam at a temperature of 160 to 165°C to prepare painted molded plates and each test was conducted. [Cement-emulsion composite coating material formulation] (A) Emulsion composition Synthetic resin emulsion (Examples 1 to 6, Comparative Examples 1 to 11) 100 parts Butyl carbitol acetate 6 parts Nopco 8034 (manufactured by San Nopco) 0.5 part tap water 10 parts (B) Inorganic admixture silica powder (average particle size 12μ) 32 parts Portland cement 15 parts Bengara MM-20 (manufactured by Nihon Bengara Co., Ltd.) 3 parts The coating film test results are shown in Table 2. From these results, it can be seen that the inorganic admixture has excellent mixing stability, and the coating film appearance after autoclave curing and coating film performance such as adhesion, freeze-thaw property, and accelerated weather resistance.

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Claims (1)

[Scope of Claims] 1 (A) The first step polymerization component is an alkyl (meth)acrylate whose alkyl group has 1 to 8 carbon atoms as the main component, and the first step monomer component is copolymerized. A monomer mixture (B) in which the theoretical glass transition temperature of the resulting copolymer is 0° C. or higher; as a second-stage polymerization component, the main component is an alkyl (meth)acrylate in which the alkyl group has 1 to 8 carbon atoms; 3-10% by weight of total second stage monomers
A monomer mixture containing as an essential component an unsaturated carboxylic acid, and the theoretical glass transition temperature of the copolymer obtained by copolymerizing the second stage monomer component is 20°C or less (C) 3rd As step polymerization components, each step polymerization component comprises a hydrophobic polyfunctional monomer having two or more double bonds in one molecule and an unsaturated monomer containing a hydrolyzable silyl group in the entire polymer. (A) is 60～
80% by weight, (B) 15-35% by weight, (C) 5-15% by weight
The first and second stages are carried out in such a way that the emulsion polymerization is carried out sequentially at a ratio of In addition to overlapping some of the
In the presence of the emulsion in which the polymerization rate of the first and second stage polymerization components has reached 90% by weight or more, the second and third stage polymerization components are
An autoclave-curable ceramic building material comprising a multi-stage sequential emulsion polymerization emulsion obtained by partially overlapping the stages and having a structure in which the surface of the second stage polymerization layer is cross-linked with high density. Painting material.