JP4898093B2 - Ceramic molding binder, green body, ceramic molded body, and ceramic bonding method - Google Patents

Description

  The present invention provides a ceramic molding binder, an aqueous ceramic slurry containing the binder and an aqueous kneaded material, a green body and a ceramic molded body obtained from the aqueous ceramic slurry or an aqueous kneaded material, and the ceramic slurry or the aqueous kneaded material as an adhesive. The present invention relates to a ceramic bonding method to be used.

  In general, a ceramic molded body is prepared by mixing ceramic powder and a molding binder in a solvent to prepare a ceramic slurry, and drying the resulting powder to form a green body. The green body is then fired. Conventionally, polyvinyl butyral, an acrylic resin, or the like has been used as the molding binder, and an organic solvent such as alcohol or an aromatic solvent has been used as the solvent. For this reason, it was necessary to install explosion-proof and fire-proof equipment against explosions and fires, and to ensure the safety and health of workers against odors and toxicity.

  In order to solve such a problem, an aqueous binder that does not use an organic solvent has been proposed. For example, Japanese Patent Publication No. 6-6504 discloses a vinyl alcohol obtained by saponifying a copolymer of a vinyl ester and a nonionic monomer having a (meth) allyl group capable of radical copolymerization with the vinyl ester. A ceramic molding binder comprising a polyvinyl alcohol-based water-soluble copolymer having a unit of 20 to 90 mol% is disclosed. However, when such a water-soluble polymer is used as a molding binder, there is a problem that the strength of the molded product is low, and in order to increase the strength, it is necessary to increase the amount of binder added. In addition, such a water-soluble polymer requires a large amount of water because the viscosity of the aqueous solution is high and difficult to handle unless the polymer content is reduced to several percent. Therefore, much energy is required for drying, which is inefficient. In addition, the toughness of the obtained green sheet is not necessarily sufficient.

  Therefore, it has been proposed to use an aqueous dispersion polymer having a low viscosity, that is, a latex. For example, JP 2000-63181 A discloses a binder containing a special acrylic emulsion and a water-soluble acrylic resin. However, when this binder is used, although the viscosity is improved, the toughness of the obtained green sheet is still not sufficient.

  Japanese Patent Application Laid-Open No. 10-120468 discloses an example in which a water-soluble polyvinyl acetal resin is modified with silane to increase the affinity with ceramic powder and to improve the toughness of the resulting green sheet. However, this binder cannot solve the increase in viscosity, which is a problem of the water-soluble polymer described above.

  On the other hand, ceramics and porcelain are often cracked or chipped by impact during the manufacturing process or distribution process. Ceramics and the like having such cracks and chips have been disposed of as industrial waste in the past because they are once baked and thus cannot be completely restored. However, in recent years, from the viewpoint of effective use of resources, it is desired to reuse these damaged ceramics.

Japanese Patent Publication No. 6-6504 JP 2000-63181 A Japanese Patent Laid-Open No. 10-120468

  The object of the present invention is that it is not necessary to use an organic solvent at the time of molding, it is possible to produce a green body having a low viscosity, excellent handling properties at the time of molding, high flexibility, sufficient toughness, and high strength. An object of the present invention is to provide a ceramic molding binder, an aqueous ceramic slurry and an aqueous kneaded material from which a fired product can be obtained.

  Another object of the present invention is to provide a green body and a ceramic molded body having sufficient toughness obtained from an aqueous ceramic slurry or an aqueous kneaded product having excellent characteristics as described above.

  Still another object of the present invention is to provide a ceramic molding binder, an aqueous ceramic slurry, an aqueous kneaded product, a green body, and a ceramic obtained by firing the green body, which are useful for reusing damaged ceramics and porcelain. The object is to provide a molded body.

  Still another object of the present invention is to provide a ceramic bonding method that is excellent in operability and workability and that provides high bonding strength.

  As a result of intensive studies to achieve the above object, the present inventors have found that a binder combining a polymer latex and a silicate compound does not require the use of an organic solvent and has low viscosity and excellent handling properties. In addition, the present inventors have found that a green body and a ceramic molded body having high strength can be produced, and the present invention has been completed.

That is, the present invention is a latex-like ceramic molding binder mainly composed of a polymer latex and 1 to 50% by weight of sodium orthosilicate or water glass in terms of SiO ₂ with respect to the entire nonvolatile content , Provided is a ceramic molding binder in which a polymer constituting the polymer latex has a quaternary ammonium base, and the polymer constituting the polymer latex is bonded to sodium orthosilicate or water glass.

The present invention also provides an aqueous ceramic slurry containing at least the ceramic molding binder and a powdered inorganic material having an average particle size of 0.1 μm to less than 500 μm .

The present invention further provides an aqueous kneaded material containing at least the binder for forming a ceramic and a particulate inorganic material having an average particle diameter of 500 to 5000 μm .

  The present invention further provides a green body obtained by molding the aqueous ceramic slurry or aqueous kneaded material.

  The present invention further provides a ceramic bonding method characterized in that a plurality of green bodies or ceramic molded bodies are joined using the aqueous ceramic slurry or aqueous kneaded material as an adhesive and then fired.

  According to the ceramic molding binder, the aqueous ceramic slurry and the aqueous kneaded material of the present invention, it is not necessary to use an organic solvent at the time of molding, the viscosity is low, the handling property at the time of molding is excellent, the flexibility is high, and the toughness is sufficient. Can be produced, and a fired product having high strength can be obtained.

  The green body of the present invention uses a water-based ceramic slurry or a water-based kneaded material having the above-described excellent characteristics, and thus is flexible and has sufficient toughness. Moreover, the ceramic molded body of the present invention has high strength.

  Moreover, according to this invention, the broken ceramics, porcelain, etc. can be reused by simple operation.

  According to the ceramic bonding method of the present invention, it is excellent in operability and workability, and one ceramic molded body bonded with high adhesive strength can be obtained from a plurality of green bodies or ceramic molded bodies.

  In the present specification, “ceramic slurry” means a slurry containing not only ceramic raw material powder but also a powdered inorganic material, and “green body” means an unsatisfactory ceramic slurry containing ceramic raw material powder. It means not only a fired molded body but also an inorganic molded body before firing a slurry or kneaded material containing a wide variety of powdered or granular inorganic materials (including those fired once). The “ceramic molded body” means a fired product of the “green body”.

[Ceramics binder]
The binder for ceramic molding of the present invention is mainly composed of a polymer latex (aqueous dispersion of polymer) and a silicate compound, and has a latex form. The binder can be produced by mixing a polymer latex and a silicate compound or an aqueous solution thereof. In such a binder, when an inorganic material such as ceramic raw material powder is added to the binder to form a water-based ceramic slurry or a water-based kneaded product, the affinity between the polymer and the inorganic material is improved through the silicate compound. Therefore, a green body that is flexible and has high mechanical strength can be obtained by molding the aqueous ceramic slurry or aqueous kneaded material. Further, the green body can be sintered at a relatively low temperature, and the vitreous formed by the condensation of silicate during firing strongly bonds the inorganic particles, so that a ceramic molded body having high strength can be obtained. Moreover, since the said aqueous ceramic slurry and aqueous | water-based kneaded material express high intensity | strength by baking, they can be utilized as a strong adhesive agent of a ceramic molded object.

  Examples of the polymer constituting the polymer latex include rubber in a broad sense including an elastomer. Examples of rubber include SBR (styrene-butadiene rubber), NBR (nitrile rubber), BR (butadiene rubber), IR (isoprene rubber), EPM (ethylene-propylene rubber), EPDM (ethylene-propylene-diene rubber), CR ( Chloroprene rubber), IIR (butyl rubber), halogenated butyl rubber, acrylic rubber, urethane rubber, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin rubber and other synthetic rubbers; NR (natural rubber); and modified products thereof (modified) Rubber) can be used. These rubbers can be used alone or in admixture of two or more.

  Among these rubbers, rubbers containing polar groups such as nitrogen atom-containing groups, oxygen atom-containing groups and sulfur atom-containing groups are preferred. In such a rubber, since a silicate compound having a high affinity with an inorganic material is easily accessible to the rubber molecule or can be bonded to the rubber molecule, the affinity between the rubber having a binder function and the inorganic material is improved as a result. In addition, the flexibility and strength of the green body and the strength of the ceramic molded body are further improved. A rubber containing a polar group is obtained by, for example, copolymerizing a monomer containing a polar group with a main monomer constituting the rubber, or grafting a monomer containing a polar group onto a rubber molecule. When the polar group can be ionized, it can be produced by ionizing the polar group by an appropriate means.

  Examples of the polar group include nitrogen atom-containing groups such as amino groups (primary, secondary, or tertiary amino groups); cations such as salts of the amino groups and onium bases such as quaternary ammonium bases. Sexual groups are preferred. As a method of introducing the cationic group into the rubber, a monomer having an amino group is subjected to copolymerization or grafting and then neutralized with an acid, and a monomer having an amino group is neutralized with an acid. A method of later subjecting to copolymerization or grafting, a method of subjecting a monomer having a quaternary ammonium base to copolymerization or grafting, and a monomer having a tertiary amino group (including -N =) Alternatively, after the grafting, a method in which an alkylating agent is reacted to quaternize the tertiary amino group can be mentioned. Examples of alkylating agents include methyl chloride, methyl bromide, methyl iodide, ethyl chloride, ethyl bromide, ethyl iodide, propyl chloride, propyl bromide, propyl iodide, butyl chloride, butyl bromide, butyl iodide. , Halogenated hydrocarbons such as benzyl chloride, benzyl bromide, epichlorohydrin or derivatives thereof (particularly alkyl halides, halogenated aralkyls, etc.). Since quaternary chlorination with an alkylating agent can be carried out in water, a polymer latex can be used for the reaction.

  As a typical example of a monomer having a nitrogen atom-containing group or a cationic group, for example, a nitrogen atom-containing heterocyclic vinyl compound such as vinylpyridine, vinylimidazole, vinylpyrrolidone or a salt thereof or a salt thereof; (2-dimethylaminoethyl) alkylaminoalkyl group-substituted aromatic vinyl compound or salt thereof such as styrene or a salt thereof; N- (dialkylaminoalkyl) such as N- (dimethylaminoethyl) (meth) acrylamide or a salt thereof ( (Meth) acrylamide or a salt thereof; and dialkylaminoalkyl (meth) acrylate or a salt thereof such as dimethylaminoethyl (meth) acrylate or a salt thereof.

  As the silicate compound, a water-soluble silicate is preferable, and typical examples thereof include sodium orthosilicate and water glass.

  In the present invention, the polymer (rubber) constituting the polymer latex and the silicate compound are uniformly dispersed or bonded from the viewpoint of improving the flexibility and strength of the green body and the strength of the ceramic molded body. Is preferred. The binder in which the polymer (rubber) constituting the polymer latex and the silicate compound are uniformly dispersed can be obtained by mixing the polymer latex and the aqueous solution of the silicate compound and sufficiently stirring them.

  The polymer in which the polymer and the silicate compound are bonded can be obtained, for example, by reacting (salt exchange) a polymer having a quaternary ammonium base and the silicate compound. The reaction can be carried out by mixing and stirring an aqueous dispersion (latex) of the polymer having the quaternary ammonium base and an aqueous solution of a silicate compound. More specifically, for example, a polymer having a pyridinium silicate group is obtained by reacting a polymer having a pyridinium halide group with water glass. In addition, as described above, the polymer having a quaternary ammonium base is a method in which a monomer having a quaternary ammonium base is copolymerized or grafted, and a monomer having a tertiary amino group is copolymerized. Alternatively, it can be obtained by grafting and then reacting an alkylating agent to quaternize the tertiary amino group. The polymer in which the polymer and the silicate compound are bonded is a reaction between a polymer having an amino group (particularly a tertiary amino group) and a silicate compound obtained by liberating the silicate compound with a strong acid (salt formation). Reaction).

The amount of the silicate compound in the binder is, for example, about 1 to 50% by weight, preferably about 5 to 20% by weight, based on the entire non-volatile content, in terms of SiO ₂ . When the amount of the silicate compound is less than 1% by weight in terms of SiO ₂ , the affinity with an inorganic material such as a ceramic raw material is low, and the reinforcing effect tends to be small. Moreover, when it exceeds 50 weight%, plasticity will fall and the toughness of a molded object will fall easily.

  Various additives may be blended in the binder as necessary.

[Water-based ceramic slurry]
The aqueous ceramic slurry of the present invention contains at least the binder for forming a ceramic and a powdered inorganic material. This aqueous ceramic slurry can be produced by mixing the ceramic-forming binder, the powdered inorganic material, and water as necessary using a mixer (such as a ball mill).

  Examples of the powdery inorganic material include metal or non-metal oxide or non-oxide powder (ceramic raw material powder; for example, porcelain clay) that can be used in the production of ceramics. The oxide includes a complex oxide containing a plurality of metals or non-metals. The powdery inorganic materials can be used alone or in combination of two or more.

  Typical examples of powdered inorganic materials include silica, alumina, zirconia, magnesia, calcium oxide, sodium oxide, potassium oxide, boron oxide, titanium oxide, zinc oxide, barium titanate, barium carbonate, aluminum silicate, sialon, spinel Examples thereof include, but are not limited to, powders such as mullite, crystallized glass, silicon carbide, silicon nitride, and aluminum nitride. The average particle size of the powdered inorganic material can be appropriately set according to the application, but when obtaining a thin green sheet, it is preferably 1 μm or less.

  The amount of the powdered inorganic material can be appropriately selected in consideration of handleability and dispersibility, but generally 5 to 99% by weight, preferably 10 to 95% by weight, more preferably 30 to 90% by weight of the entire aqueous ceramic slurry. It is about wt%. If the amount of the inorganic powder material is too small, the viscosity of the slurry becomes too low and the handling property when forming a green body tends to decrease, and if too large, the viscosity of the slurry increases and the dispersibility tends to decrease. .

  If necessary, additives such as glass frit, plasticizer, dispersant, lubricant, wetting agent, antistatic agent, antifoaming agent, and drying accelerator may be added to the aqueous ceramic slurry.

  According to the aqueous ceramic slurry of the present invention, since the binder is used, it is not necessary to use an organic solvent at the time of molding, and the viscosity is low and the handling property at the time of molding is excellent. In addition, a green body having high flexibility and sufficient toughness can be produced, and a fired product having high strength can be obtained.

[Water-based kneaded product]
The aqueous kneaded product of the present invention contains at least the ceramic molding binder and a powdery or granular inorganic material. This water-based kneaded product can be produced by kneading the ceramic molding binder, a powdered or granular inorganic material, and, if necessary, water with a kneader or the like.

  As the powdered or granular inorganic material, in addition to the powdered inorganic material such as the ceramic raw material powder, for example, a pulverized product of a material having no binding force or plasticity such as silica or ceramic waste once fired (crushing of ceramics or porcelain) Etc.). The average particle size of the powdered or granular inorganic material can be appropriately set according to the use, but is generally about 0.1 to 5000 μm.

  The amount of the powdery or granular inorganic material can be appropriately selected in consideration of handleability and dispersibility, but is generally about 50 to 99% by weight, preferably about 60 to 90% by weight, based on the entire aqueous kneaded material. If the amount of the powdery or granular inorganic material is too small, the energy required for drying increases and the cost is likely to increase, and if it is too large, the bonding strength is lowered and the strength of the green body and the fired product is likely to be reduced.

  If necessary, additives such as glass frit, plasticizer, dispersant, lubricant, wetting agent, antistatic agent, antifoaming agent, and drying accelerator may be added to the aqueous kneaded product.

  According to the aqueous kneaded material of the present invention, since the binder is used, it is not necessary to use an organic solvent at the time of molding, and the viscosity is low and the handling property at the time of molding is excellent. In addition, a green body having high flexibility and sufficient toughness can be produced.

  Moreover, resources can be effectively used by using a pulverized product of a ceramic molded body such as damaged ceramic or porcelain as a powdery or granular inorganic material. In this case, when a granular material having a relatively large diameter (for example, one having an average particle size of about 500 to 5000 μm) is used, it is molded into a green body, and further fired to form a porous molded body. Can be obtained. This porous molded body can be used as a water permeable block laid on a sidewalk or the like in a park. In addition, a large-diameter granular material among the pulverized material of the ceramic molded body and an unfired powdered inorganic material such as a ceramic raw material powder (for example, those having an average particle diameter of about 0.1 μm to less than 500 μm) are used in combination. In this case, a green body is formed and then fired to obtain a ceramic body having a rough surface and high strength. Such a ceramic molded body can be used as, for example, a tile having an uneven surface and an excellent design.

[Green body]
The green body of the present invention can be obtained by molding the aqueous ceramic slurry or the aqueous kneaded material. The shape of the green body is not particularly limited, and in addition to the sheet shape (green sheet), depending on the use of the final fired product (ceramic shaped body) such as a granule shape, a lump shape, a column shape (a prismatic shape, a cylindrical shape, etc.) It can be selected as appropriate. As the molding method, a general molding method (sheet molding (dip molding, reverse roll coater molding, doctor blade molding, etc.), press molding, extrusion molding, mud slurry for producing a molded product according to the shape of the green body. Cast molding, granulation, a combination of these, etc.] can be employed. After molding, it is subjected to drying as necessary.

  The green body of the present invention uses the above-mentioned water-based ceramic slurry or water-based kneaded material as a forming raw material, and is flexible and has sufficient toughness. Therefore, a high-strength fired product (ceramic compact) can be obtained.

[Ceramic compacts]
The ceramic molded body of the present invention can be obtained by firing the green body. Although a calcination temperature can be suitably selected according to the use etc. of a target object, generally it is 700-1500 degreeC, Preferably it is about 800-1400 degreeC.

  Since the ceramic molded body of the present invention uses the green body having the excellent characteristics as described above, it has high strength.

[Ceramic bonding method]
In the ceramic bonding method of the present invention, a plurality of green bodies or ceramic molded bodies are bonded using the ceramic slurry or aqueous kneaded material of the present invention as an adhesive, and then fired. In this method, the green bodies and the ceramic molded bodies may be joined, or the green body and the ceramic molded bodies may be joined.

  There are no particular limitations on the green body and the ceramic molded body that are the joined bodies, and any of a green body, a ceramic molded body, a green body of the present invention, and a ceramic molded body manufactured by a known method may be used. . Further, the shapes of the green body and the ceramic molded body, which are the joined bodies, are not particularly limited, and may be any of a granular shape, an indeterminate shape, a lump shape, a plate shape, a column shape (a prismatic shape, a cylindrical shape, etc.)

  The amount of the ceramic slurry or water-based kneaded material used as the adhesive is not particularly limited as long as it is an amount sufficient to join the objects to be joined. Moreover, the application method of the ceramic slurry or aqueous kneaded material used as the adhesive is not particularly limited, and a commonly used method such as an injection method or a method using a trowel can be employed.

  After joining to-be-joined bodies, it dries as needed and then bakes. The firing temperature can be appropriately selected according to the type of constituent material of the object to be bonded, the intended use of the object, etc., but is generally about 500 to 1500 ° C., preferably about 700 to 1400 ° C.

  According to the ceramic bonding method of the present invention, since the above ceramic slurry or water-based kneaded material is used, it is excellent in operability and workability, and is bonded from a plurality of green bodies or ceramic molded bodies with high adhesive strength. A ceramic molded body can be obtained.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.

Example 1
Latex of styrene-butadiene-vinylpyridine terpolymer (VpSBR) [manufactured by Nippon Zeon Co., Ltd., trade name “Lx605”, solid content 40 wt%, monomer ratio (weight ratio): styrene / butadiene / vinylpyridine = 15/60/25] was diluted with distilled water to prepare a polymer latex having a solid content of 20% by weight. A solution of 1.2 g of propyl bromide in 15 g of tetrahydrofuran (THF) was added to 600 g of the above polymer latex in small portions while stirring, and the mixture was stirred for 2 hours at room temperature. The tertiary amino group of the ring was quaternized and a quaternary chloride VpSBR latex was obtained.
On the other hand, No. 3 water glass [manufactured by Fuji Chemical Co., Ltd., solid content 30 wt%] was diluted with distilled water to prepare a water glass solution having a solid content of 20 wt%.
To the quaternary chloride VpSBR latex, 120 g of a water glass solution having a solid content of 20% by weight was added little by little with stirring, and the mixture was stirred at room temperature for 1 hour to prepare a binder. The amount of silicate in the binder is about 16% by weight based on the entire non-volatile content (polymer + silicate) in terms of SiO ₂ .
20 parts by weight of the above binder and ceramic powder [porcelain clay, average particle size (primary particles) 25 μm, composition: SiO ₂ (about 73 wt%), Al ₂ O ₃ (about 16 wt%), CaO (about 2 % By weight), MgO (about 1% by weight), Na ₂ O + K ₂ O (about 6% by weight)] in a mortar and mixed with rubbing with a pestle to obtain a ceramic slurry. This slurry was spread on a water-permeable plate (unglazed ceramic plate), left at room temperature to remove moisture, and then passed through a 12-mesh sieve to obtain a powdery green body. The powdery green body is filled into a 60 mm × 60 mm × 5 mm mold, press-molded at a pressure of 300 kgf / cm ² (29.4 MPa), and dried in an oven at 120 ° C. for 24 hours to produce a green sheet. did. This green sheet was fired at a temperature of 1200 ° C. to obtain a ceramic molded body (fired product).

Reference example 1
Latex of styrene-butadiene-vinylpyridine terpolymer (VpSBR) [manufactured by Nippon Zeon Co., Ltd., trade name “Lx605”, solid content 40 wt%, monomer ratio (weight ratio): styrene / butadiene / vinylpyridine = 15/60/25] was diluted with distilled water to prepare a polymer latex having a solid content of 20% by weight.
On the other hand, No. 3 water glass [manufactured by Fuji Chemical Co., Ltd., solid content 30 wt%] was diluted with distilled water to prepare a water glass solution having a solid content of 20 wt%.
To 10 parts by weight of the polymer latex having a solid content of 20% by weight, 4 parts by weight of the water glass solution having a solid content of 20% by weight and 6 parts by weight of distilled water are added little by little while stirring, and the mixture is stirred at room temperature for 1 hour. A binder was prepared. The amount of silicate in the binder is about 16% by weight based on the entire non-volatile content (polymer + silicate) in terms of SiO ₂ .
20 parts by weight of the above binder and ceramic powder [porcelain clay, average particle size (primary particles) 20-30 μm, composition: SiO ₂ (about 73% by weight), Al ₂ O ₃ (about 16% by weight), CaO ( About 2 wt%), MgO (about 1 wt%), Na ₂ O + K ₂ O (about 6 wt%)] in a mortar and mixed with rubbing with a pestle to obtain a ceramic slurry. This slurry was spread on a water-permeable plate (unglazed ceramic plate), left at room temperature to remove moisture, and then passed through a 12-mesh sieve to obtain a powdery green body. The powdery green body is filled into a 60 mm × 60 mm × 5 mm mold, press-molded at a pressure of 300 kgf / cm ² (29.4 MPa), and dried in an oven at 120 ° C. for 24 hours to produce a green sheet. did. This green sheet was fired at a temperature of 1200 ° C. to obtain a ceramic molded body (fired product).

Comparative Example 1
No. 3 water glass [manufactured by Fuji Chemical Co., Ltd., solid content 30 wt%] was diluted with distilled water to prepare a water glass solution having a solid content of 20 wt%. To 4 parts by weight of the water glass solution having a solid content of 20% by weight, 16 parts by weight of distilled water was added little by little with stirring, and the mixture was stirred at room temperature for 1 hour to prepare a binder.
20 parts by weight of the above binder and ceramic powder [porcelain clay, average particle size (primary particles) 20-30 μm, composition: SiO ₂ (about 73% by weight), Al ₂ O ₃ (about 16% by weight), CaO ( About 2 wt%), MgO (about 1 wt%), Na ₂ O + K ₂ O (about 6 wt%)] in a mortar and mixed with rubbing with a pestle to obtain a ceramic slurry. This slurry was spread on a water-permeable plate (unglazed ceramic plate), left at room temperature to remove moisture, and then passed through a 12-mesh sieve to obtain a powdery green body. The powdery green body is filled into a 60 mm × 60 mm × 5 mm mold, press-molded at a pressure of 300 kgf / cm ² (29.4 MPa), and dried in an oven at 120 ° C. for 24 hours to produce a green sheet. did. This green sheet was fired at a temperature of 1200 ° C. to obtain a ceramic molded body (fired product).

Comparative Example 2
Latex of styrene-butadiene-vinylpyridine terpolymer (VpSBR) [manufactured by Nippon Zeon Co., Ltd., trade name “Lx605”, solid content 40 wt%, monomer ratio (weight ratio): styrene / butadiene / vinylpyridine = 15/60/25] was diluted with distilled water to prepare a polymer latex having a solid content of 20% by weight.
To 10 parts by weight of the polymer latex having a solid content of 20% by weight, 10 parts by weight of distilled water was added little by little with stirring, and the mixture was stirred at room temperature for 1 hour to prepare a binder.
20 parts by weight of the above binder and ceramic powder [porcelain clay, average particle size (primary particles) 20-30 μm, composition: SiO ₂ (about 73% by weight), Al ₂ O ₃ (about 16% by weight), CaO ( About 2 wt%), MgO (about 1 wt%), Na ₂ O + K ₂ O (about 6 wt%)] in a mortar and mixed with rubbing with a pestle to obtain a ceramic slurry. This slurry was spread on a water-permeable plate (unglazed ceramic plate), left at room temperature to remove moisture, and then passed through a 12-mesh sieve to obtain a powdery green body. The powdery green body is filled into a 60 mm × 60 mm × 5 mm mold, press-molded at a pressure of 300 kgf / cm ² (29.4 MPa), and dried in an oven at 120 ° C. for 24 hours to produce a green sheet. did. This green sheet was fired at a temperature of 1200 ° C. to obtain a ceramic molded body (fired product).

Comparative Example 3
20 parts by weight of distilled water and ceramic powder [porcelain clay, average particle size (primary particles) 20-30 μm, composition: SiO ₂ (about 73% by weight), Al ₂ O ₃ (about 16% by weight), CaO (about 2 wt%), MgO (about 1 wt%), Na ₂ O + K ₂ O (about 6 wt%)] in a mortar and mixed while rubbing with a pestle to obtain a ceramic slurry. This slurry was spread on a water-permeable plate (unglazed ceramic plate), left at room temperature to remove moisture, and then passed through a 12-mesh sieve to obtain a powdery green body. The powdery green body is filled into a 60 mm × 60 mm × 5 mm mold, press-molded at a pressure of 300 kgf / cm ² (29.4 MPa), and dried in an oven at 120 ° C. for 24 hours to produce a green sheet. did. This green sheet was fired at a temperature of 1200 ° C. to obtain a ceramic molded body (fired product).

Evaluation Test The viscosity and handling properties of the ceramic slurries obtained in the examples and comparative examples, the flexibility and strength of the green sheet, and the strength of the fired product were evaluated by the following methods. The results are shown in Table 1.

(Viscosity of ceramic slurry)
When the ceramic slurry was prepared, the degree of viscosity when mixing in a mortar was relatively compared using Comparative Example 3 as a standard.
○: The degree of viscosity is the same as or lower than that of Comparative Example 3.
X: The degree of viscosity is higher than that of Comparative Example 3.

(Ceramic slurry handling properties)
The handling property in preparing the ceramic slurry was evaluated according to the following criteria.
○: No debris (lumps) are formed and uniform.
Δ: A small amount of dama can be produced.
X: A large amount of balls can be formed, and it is difficult to make uniform.

(Green sheet flexibility)
The condition when the green sheet before drying was bent by hand was observed, and the flexibility was evaluated according to the following criteria.
A: Even if bent by hand, it is flexible and not cracked like rubber.
○: Although it has flexibility, it may crack when bent by hand.
(Triangle | delta): If it bends by hand, it will crack easily.
X: Cracked very easily when bent by hand.

(Green sheet strength)
The state when the dried green sheet was dropped from a height of 80 cm onto the floor was observed, and the strength was evaluated according to the following criteria.
A: There is no damage at all.
○: Cracking occurs.
Δ: Some chipping occurs.
X: It breaks apart.

(Strength of fired product)
The force required to break the fired product (ceramic molded body) with a steel hammer was relatively compared using Comparative Example 3 as a standard.
A: A greater force than that of Comparative Example 3 is required to break.
○: The same level of force as in Comparative Example 3 is required to break.
Δ: Breaking with a slightly smaller force than Comparative Example 3.
X: It is destroyed even with a considerably smaller force than Comparative Example 3.

Example 3
20 parts by weight of a binder prepared in the same manner as in Example 1 and a ground ceramic (Serbene, average particle size of about 1.5 mm, composition: SiO ₂ (about 75% by weight), Al ₂ O ₃ (about 16% by weight) , 100 parts by weight of CaO (about 2% by weight), MgO (about 1% by weight), Na ₂ O + K ₂ O (about 6% by weight) in a beaker, and mix evenly with a stir bar or spatula Thus, an aqueous kneaded product was obtained. This kneaded material was filled into a cardboard cylinder (inner diameter 30 mm, length 120 mm) and fired at 1200 ° C. as it was. The obtained fired product was porous and had a practically sufficient strength for a water-permeable block. The operability when filling the kneaded material into a cardboard cylinder was also good.

Example 4
100 g of the binder prepared in the same manner as in Example 1 and 20 g of glass powder (Na ₂ O—CaO—B ₂ O ₃ —SiO ₂ system, average particle size of about 90 μm) were mixed and stirred to obtain a ceramic slurry. It was. This slurry was applied to one side of a 25 mm square tile, pressed against one side of another square tile of the same size, allowed to stand for a while, and then dried at 120 ° C. At this point, the two tiles were firmly bonded. Next, when this was baked at 700 ° C., the two tiles were completely bonded. The bending strength of the obtained composite was measured according to JIS A 5209, and as a result, it was 194 N / cm. In addition, the bending strength (JIS A 5209) of the tile used at this time is 200 N / cm.

Example 5
In Example 4, the same operation as in Example 4 was performed except that the firing temperature was 800 ° C., and the two tiles were completely bonded. The bending strength of the obtained composite was measured in accordance with JIS A 5209. As a result, it was 186 N / cm.

Claims (5)

A latex-forming ceramic binder comprising, as a main component, a polymer latex and 1 to 50% by weight of sodium orthosilicate or water glass in terms of SiO ₂ with respect to the entire non-volatile content , the polymer constituting the polymer latex A binder for forming ceramics, wherein quaternary ammonium base is contained and the polymer constituting the polymer latex is bonded to sodium orthosilicate or water glass.   A water-based ceramic slurry comprising at least the ceramic molding binder according to claim 1 and a powdered inorganic material having an average particle size of 0.1 µm to less than 500 µm.   A water-based kneaded product comprising at least the ceramic molding binder according to claim 1 and a particulate inorganic material having an average particle size of 500 to 5000 µm.   A green body obtained by molding the aqueous ceramic slurry according to claim 2 or the aqueous kneaded material according to claim 3.   A ceramic bonding method comprising bonding a plurality of green bodies or ceramic molded bodies using the aqueous ceramic slurry according to claim 2 or the aqueous kneaded material according to claim 3 as an adhesive, followed by firing.