JP2939886B2 - Manufacturing method of lightweight ceramic body molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a method for producing a lightweight ceramic body molded body useful as a building material such as a ceiling material, a wall material, a tile, or a toy.

[Prior art]

Lightweight concrete is known as a lightweight building material,
This lightweight concrete is excellent in heat insulation. On the other hand, in the case of manufacturing a lightweight ceramic, the resin was burned and dissipated by mixing a resin foam small piece and water with the ceramic base powder, kneading the clay, and firing the molded ceramic base. Only perforated porcelain can be obtained (JP-A-62-162665). It is also conceivable to obtain a lightweight ceramic by mixing an inorganic lightweight aggregate such as pearlite and vermiculite and water with the ceramic base powder, kneading the mixture, and firing the molded green ceramic base. Can't get a consistent pottery.

[Problems to be solved by the invention]

The present inventor tried to produce lightweight ceramics using a resin aqueous emulsion instead of resin foam pieces,
Only those with a specific gravity of 1.8 or more were obtained. This is because, in order for the ceramic green body to have sufficient strength to maintain its shape, the amount of the emulsion to be mixed with the ceramic body powder, in other words, the amount of water used is limited. Further, the inventor of the present invention intends to produce a lightweight ceramic green body by mixing a resin aqueous emulsion with a ceramic body powder (porcelain clay) to obtain a slurry, coagulating the slurry to obtain a water-containing molded product, and drying this. And the second of the attached drawings
As shown in the figure, the specific gravity of the resin emulsion (approximately 1.0
Due to the difference in specific gravity (2.1 to 4.2) between 2) and the ceramic body powder, the resin emulsion was separated into three layers: an upper layer 1, a water tank (intermediate layer) 2, and a lower layer 3 of the sedimented ceramic body powder. Accordingly, an object of the present invention is to provide a method for producing a lightweight ceramic body molded body having a specific gravity of 1.5 or less, preferably 1 or less. In the present invention, in order to obtain a uniform mixed slurry, a specific anionic resin aqueous emulsion is used, and an emulsion breaking agent is added to a mixed slurry of porcelain clay, water and an anionic resin aqueous emulsion to break the emulsion, A water-containing molded body is obtained by aggregating and adhering the emulsion resin particles onto the powder, and the molded body is removed and dried to obtain a lightweight ceramic body molded body having a specific gravity of 1.5 or less, preferably 1 or less.

[Means for Solving the Problems]

In order to achieve the above object, a method for producing a light-weight ceramic body molded product characterized by the present invention is a method for manufacturing a lightweight ceramic body powder (A) by using 100 parts by weight of an anionic copolymer aqueous emulsion (B). A mixed solution containing 3 to 50 parts by weight in terms of solid content, 15 to 150 parts by weight of an inorganic compound (C) which generates ions in water, and an appropriate amount of water (D) was heated to a temperature of (B). The temperature is higher than the glass transition point (Tg) of the copolymer in the aqueous emulsion of the component, and is maintained at a temperature not higher than + 45 ° C. by the ion derived from the compound of the component (C) and the anionic surfactant. A chelate is formed, the emulsion copolymer particles of the component (B) are aggregated by the formation of the chelate to form a molded body holding the powder (A) and water, and then the molded body is dried. is there. Next, the production of each component and the lightweight ceramic body molded article in the above configuration will be described. [Powder for ceramics] The powder for ceramics of the component (A), which is a clay such as kaolin, montmorillonite, mica, talc, pyrophyllite, jamonite, mudstone, silica, and wax In addition to general ceramic base such as non-plastic raw materials such as base powder, glass frit, alumina, silicon nitride,
Magnesia, zirconia, beryllia, thoria,
Spinel, Cordierite, Lisha, Iron lantern
Special ceramic bodies such as jammonite, steatite, titanium oxide, barium titanate, celsian, and ferrite are used. [Aqueous emulsion of anionic copolymer] The aqueous emulsion of anionic copolymer (B) is obtained by emulsion-polymerizing a vinyl monomer using an anionic surfactant which forms a chelate compound with calcium ions or magnesium ions. An aqueous copolymer emulsion obtained, wherein the carboxyl group concentration in the copolymer is 0%.
0.30.3% by weight of an anionic copolymerized water-resistant emulsion. However, the amount of the anionic surfactant used per 100 parts by weight of the copolymer is 0.6 to 2.5 parts by weight in solid form. Here, the carboxyl group concentration in the copolymer is represented by the weight% of the constituent unit based on α, β-unsaturated acid in the copolymer with respect to the total weight of the vinyl monomer forming the copolymer. As the α, β-unsaturated acid, acrylic acid, methacrylic acid, fumaric acid, itaconic acid, crotonic acid, maleic anhydride and the like are used. When the α, β-unsaturated acid is one that gives a copolymer having many carboxyl groups on the surface of the copolymer particles, such as acrylic acid, itaconic acid, fumaric acid, and maleic anhydride, When giving a copolymer having a concentration of less than 0.1% by weight and a copolymer having many carboxyl groups inside the copolymer particles such as methacrylic acid, the carboxyl group concentration is not more than 0.3% by weight. The amount of the α, β-unsaturated acid using emulsion polymerization is adjusted so as to obtain the following. (C) Ca ⁺⁺ and Mg ⁺⁺ generated from the calcium compound or the magnesium compound of the component react with an anionic surfactant to form a chelate compound, and copolymer particles of an emulsion having a carboxyl group are also used. It traps ions to form chelates. Therefore, the chelating reaction with the anionic surfactant is delayed, or (c)
When the component is gypsum, it causes the hydration-hardening reaction of the gypsum to be delayed. Therefore, the resin of the aqueous emulsion of the anionic copolymer for the component (B) should contain carboxyl groups as little as possible on the particle surface. It is preferable that the compound does not have an acid group. When α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic anhydride and crotonic acid are used as the vinyl monomer, the carboxyl group in the copolymer The base concentration is used so as to be lower than the above-mentioned concentration. If this concentration is exceeded, a large amount of Ca or Mg is eaten by the resin of the aqueous emulsion, and the time required for coagulation of the mixed slurry becomes long. (C) Ca ⁺⁺ and Mg ⁺⁺ generated from components, or (A) Ca ⁺⁺ and Mg ⁺⁺ in the component, ammonia emulsifiers ions and K ^+,
By chelating by ion exchange with metal ions such as Na ⁺ and Li ⁺ , for example, the emulsifier becomes an organic calcium sulfonate or a calcium organic carboxylate having a reduced hydrophilicity, the surface activity of the emulsifier is reduced, and the emulsion is destroyed. The copolymer particles agglomerate and coagulate, and adhere to solid powders such as the ceramic body powder of the component (A) to form a water-containing ceramic green body. Examples of such anionic emulsifiers include organic acids such as sodium laurate sulfonate, sodium stearate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfonate, sodium alkane sulfonate, and sodium alkylbenzene sulfonate. sulfonic acid soda salt, aliphatic soaps, fatty acid sarcosides, fatty acid metal salts such as rosin acid soap; these Na ⁺ in place of K ^+, NH ₄ ^+,
A sulfate ester type anionic surfactant having an alkanolamine ion or a fatty acid derivative can be used. These anionic emulsifiers are used in a proportion of 0.6 to 2.5 parts by weight in solid content based on 100 parts by weight of the copolymer of the obtained aqueous emulsion. If the amount is larger than this, coagulation of the copolymer particles, which is expected to have a small destruction effect of the emulsifier, will not occur partially or at all, and the hydration hardening reaction of gypsum will be inhibited. On the other hand, when the amount is small, the polymerization stability and storage stability of the copolymer aqueous emulsion are low, and the aggregation of the copolymer particles is fast, so that there is a problem in the mixing stability with the ceramic base powder. That is, if the amount is less than 0.6 parts by weight, the rate of generation and agglomeration of the aggregates of the copolymer particles is high, and it is not possible to obtain a ceramic body molded body in which the ceramic base powder, the copolymer aqueous emulsion and water are uniformly mixed. Before that, the emulsion polymerization of the emulsion cannot be carried out stably. If it exceeds 2.5 parts by weight, aggregation of the copolymer particles of the emulsion,
In addition to the time required for coagulation, depending on the constituent parts of the copolymer of the emulsion, as shown in FIG.
An upper layer 12 is formed separately from the aqueous solution, and the aqueous emulsion of the anionic copolymer is not effectively used. A nonionic surfactant such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, or polyoxyethylated castor oil may be used in combination with the anionic emulsifier. This nonionic emulsifier has the ability to protect and stabilize the copolymer resin particles from Ca ⁺⁺ and Mg ⁺⁺ without being subjected to a coagulation action by Ca ⁺⁺ , Mg ⁺⁺ or the like. Further, it is stable and effective at the time of polymerization of the resin emulsion, and is effective as a dispersant for the base powder for ceramics and the inorganic compound as the component (C). However, if it is used in excess of 2%, a part of the resin emulsion cannot be aggregated, so that it is better to use as little as possible. Therefore, 0 to the copolymer particles of the component (B).
It is preferable to mix a nonionic emulsifier during or after polymerization in the range of 2%. Examples of the vinyl monomer that gives an anionic copolymer include alkyl acrylate and alkyl methacrylate (the alkyl group has 1 to 8 carbon atoms); 2-hydroxyethyl acrylate,
Hydroxypropyl acrylate and their methacrylate equivalents; acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, ethylene, acrylonitrile, esters such as methyl methacrylate, vinyl acetate,
Styrene, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, maleic anhydride, etc. can be used. Two or more of these vinyl monomers are selected, and the glass transition of the copolymer particles of the obtained aqueous emulsion is obtained. The point is preferably −30 ° C. to + 30 ° C., and the vinyl monomer is selected such that the amount of carboxyl groups in the copolymer falls within the range described above. In addition, what is called a reactive emulsifier, such as sodium vinyl sulfonate, is handled as an anionic emulsifier if it is an anion. Emulsion polymerization is carried out in a usual manner, and the resulting resin aqueous emulsion generally has a resin solids concentration of 20 to 65% by weight and a copolymer particle diameter of 0.03 to 3 microns. The amount of the aqueous anionic copolymer aqueous emulsion greatly depends on the type of the vinyl monomer constituting the copolymer. Generally, the component (A) is a ceramic base powder.
It is 3 to 50 parts by weight based on 100 parts by weight of the solid content of the copolymer. If the amount is less than 3 parts by weight, it is not possible to obtain a lightweight ceramic base material having a specific gravity of 1.5 or less, and the mixed slurry lacks stability. If the amount exceeds 50 parts by weight, the amount of the inorganic compound (C) required for coagulating the emulsion resin becomes large, and the ceramic properties of the obtained product are impaired. Emulsion of component (B) The amount of component (A) to be used with respect to the ceramic base powder depends largely on the type of the vinyl monomer constituting the copolymer of the emulsion as described above, and is generally an acid group, a hydroxyl group or an amide. Those having a functional group such as a group tend to have a lower upper limit of the amount used than a copolymer having no such functional group. [Inorganic compounds that generate calcium ions or magnesium ions in water] As the calcium compounds and magnesium compounds of component (C) that generate Ca ⁺⁺ and Mg ⁺⁺ in water, sulfates, oxides, and carbonates of calcium and magnesium are used. Substances, hydroxides, chlorides and the like are used. Specifically, gypsum, calcium oxide, magnesium oxide and the like are used. These compounds are used in an amount sufficient to destroy the emulsion. Particularly, gypsum and magnesium oxide are preferred because they themselves have hydration-hardening properties. Alum-like as forming chelate compound with anionic emulsifier
Although Al ⁺⁺⁺ is generated in water, the emulsion is rapidly destroyed, and it is not possible to obtain a ceramic green body having a uniform structure. [Water] The water of the component (D) contributes to the hydration hardening reaction when the component (C) is gypsum, but the main purpose is to make the clay, resin particles and ( It serves as a dispersion medium for the inorganic compound as the component (C). Also,
Water is also a preparation agent for obtaining a lightweight ceramic body molded article having a desired specific gravity. [Optional Components] In addition, lightweight aggregates such as foamed shirasu balloons and foamed glass aggregates, extenders such as titanium oxide and clay, and coloring agents such as iron oxide and chromium oxide may be blended. [Manufacture of Light-Weight Ceramic Body Molded Body] In order to manufacture a light-weight ceramic body molded body, as shown in FIG. 1 (a) of the accompanying drawings, (A) component ceramic body powder (porcelain clay) and (B) The anionic copolymer aqueous emulsion of the component and the water of the component (D) are uniformly dispersed and mixed in a mold,
Next, as shown in FIG. 2 (b), an emulsion-disintegrating agent such as gypsum of the component (C) is added to form a uniform mixed slurry under stirring, and as shown in FIG. When the coalesced particles start to adhere to the clay, the stirrer is taken out of the mold, and the aggregation and adhesion of the copolymer particles of the emulsion to the clay are completed to obtain a molded body of hydrated ceramic green body. In this case, the time required for aggregation is 20-180 minutes,
Further, the aggregation temperature is higher than the glass transition point (Tg) of the copolymer particles of the emulsion of the component (B) and "Tg + 45".
° C ”or lower. This liquid temperature may be the temperature of water or the heating of the mixture. As a matter of course, when the inorganic compound of the component (C) is gypsum, the reaction generates heat and rises automatically. The liquid temperature of the component (C) at the time of mixing gypsum, for example, is an important factor in the present invention, and the fusion force of the aqueous emulsion copolymer particles of the component (B) is effectively utilized.
Therefore, the liquid temperature is higher than the Tg of the copolymer, and the Tg
Keep the temperature below + 45 ° C. At a temperature lower than Tg, the cohesive force of the copolymer particles is not exhibited, and at a temperature lower than Tg, even if the copolymer particles in the emulsion are subjected to an aggregating action by Ca ⁺⁺ or the like, the copolymer in the emulsion is not affected. Adhesive force (film-forming power) between the particles and between the copolymer particles and the clay and the various additional components cannot be expected, and the clay (C) and (C) from the mixture of the components (A), (B) and (C) cannot be expected. ) The sedimentation of the components proceeds,
Large separation of water will occur. However, even before the component (C) is mixed, even if the liquid temperature is lower than Tg, after the component (C) is mixed, heat is generated as the hydration reaction of the gypsum proceeds with the lapse of time, so that the liquid temperature of the mixed solution becomes Although it may rise and exceed Tg, it is impractical because it is necessary to stir the liquid so as not to cause separation to obtain a uniform mixed liquid. Next, when the temperature is higher than “Tg + 45 ° C.”, since the copolymer particles of the component (B) are too soft, the small particles of the copolymer are immediately aggregated when mixed, and at the same time, Cohesion of the copolymer particles, clay and gypsum occurs at the moment of fusion, resulting in the formation of a gum or a significant thickening of the liquid. I can't get my body. The temperature of the hydration hardening reaction of the mixed solution is preferably Tg + (10 to 30) ° C. Although the difference in Tg tends to be different depending on the conditions, in the present invention, the Tg was measured at a heating rate of 10 ° C./min using a model 1090 differential thermal analyzer manufactured by DuPont. In the gypsum of the component (C), the hydration reaction starts at the same time as the mixing, and Ca ⁺⁺ appears. Ca ⁺⁺ from gypsum replaces the metal or ammonium ions of the anionic emulsifier that controls the emulsification function in the emulsion, and the emulsifier becomes a hydrophobic salt to reduce or eliminate its emulsification function, and the emulsion copolymer At the same time as aggregating the particles, the copolymer particles and the clay, gypsum particles are linked,
The viscosity of the mixed slurry rises and solidifies to obtain a hydrous ceramic green body. During the coagulation and coagulation of the copolymer particles of this emulsion, excess water may be separated and become a supernatant. Then, the water-containing porcelain green body molded body solidified as shown in FIG. 1 (d) is taken out of the mold and dried as shown in FIG. 1 (e) to have a specific gravity of 0.4 to 1.
5, preferably 0.5 to 0.8 lightweight ceramic body molding. Next, as shown in FIG. 6F, a glaze is applied to the surface of the lightweight ceramic body molded body, glazed, and fired at a high temperature of 1000 to 1400 ° C., thereby obtaining a lightweight ceramic having a specific gravity of 0.34 to 1.6.

【Example】

Hereinafter, the present invention will be described in more detail with reference to examples. The parts and percentages in the examples are on a weight basis unless otherwise specified. First, a production example of the aqueous resin emulsion will be described. Production Example 1 The following materials were charged into a reaction vessel equipped with a temperature controller, a squirrel stirrer, a reflux condenser, a supply vessel, a thermometer, and a nitrogen inlet tube. 200 parts of water 35% aqueous solution of sodium salt of sulfuric acid half ester of p-nonylphenol (anionic emulsifier a) reacted with 20 mol of ethylene oxide 3.9 parts Then, the inside of the reaction vessel is replaced with nitrogen gas, and 10% of I was added and the mixture was heated to 90 ° C. Feed I water 200 parts 35% aqueous solution of the anionic emulsifier 19 parts Styrene 192 parts N-butyl acrylate 194 parts Acrylamide 14 parts Further, 2.5 parts of potassium persulfate dissolved in 85 parts of water (Feed II) ) Is charged into the reaction vessel, and all the remaining feed I and 90% of the feed II are fed into the reaction vessel over 3.5 hours. After the feed is completed, the temperature is maintained at the same temperature for 2 hours. Feed I was polymerized to give an aqueous anionic resin emulsion (Tg + 17 ° C.) having a —COOH content of 0% by weight. Production Examples 2 to 15 The aqueous emulsion of the copolymer particles having the physical properties shown in the table was obtained by changing the type of the vinyl monomer and the type and amount of the emulsifier as shown in Table 1. The nonionic emulsifier was initially charged in the reaction vessel. Example 1 310 parts by weight of a dispersed clay slurry composed of 10 parts by weight of feldspar, 60 parts by weight of clay, 30 parts by weight of silica, and water residue (solid fraction 33
%), 40 parts by weight of the aqueous emulsion of the anionic acrylic copolymer (solid content: about 50% by weight) obtained in Production Example 1 and 100 parts by weight of water were stirred and mixed to obtain a uniform mixed slurry. 150 parts by weight of α-gypsum was added to the mold containing the mixed slurry at 25 ° C., and after about 30 minutes, heat generation was observed, so the stirrer was taken out and left for 90 minutes to complete coagulation. Inside was one layer. Take out the hydrated ceramic green body from the mold and dry it in a 45 ° C constant temperature room for 12 hours.
m, a specific gravity of 0.75, and a compressive strength of about 0.8 kg / cm ² were obtained. Examples 2 to 11 and Comparative Examples 1 to 4 Lightweight ceramic body moldings shown in Table 2 below were obtained in the same manner except that the emulsions of Production Examples 2 to 15 were used instead of the emulsion of Production Example 1. Examples 12-15, Comparative Examples 5-6 Instead of α-gypsum as a breaking agent, β-gypsum, CaO, M
Molding was performed in the same manner as in Example 1 except that gO and Al ₂ SO ₄ .16H ₂ O were used, or that no breaking agent was used. The physical properties of the obtained molded product are shown in Table 3 below. Examples 16 to 21 In Example 1, the mixing ratio of each component and the temperature were set forth in Table 4 below.
A light-weight ceramic body molded article having the physical properties shown in the same table was obtained in the same manner except for the following changes. Application Example 70 parts by weight of water was added to 100 parts by weight of a commercially available lead glaze, and the mixture was ground and mixed by a ball mill (solid content: about 58%, pH 9.3). 10 parts by weight of the aqueous anionic resin emulsion (solid content 50% by weight, pH 6.0) obtained in Production Example 2 was blended with 100 parts by weight of the dispersed glaze liquid to obtain a raw glaze. This raw glaze was spray-painted on the surface of the lightweight ceramic body formed body obtained in Examples 1 to 11, and after pre-drying at 150 ° C., the pattern layer printed on the transfer paper on the surface of this raw glaze layer was water slide. Transferred by the method, the painted body was second fired (glazed) at 1250 ° C. to obtain a painted lightweight ceramic. The specific gravity of these lightweight ceramics was equal to or slightly lower than the specific gravity of the lightweight ceramic body before molding. Also,
The pattern of the lightweight porcelain was clear and good with no glaze collapse or pinholes.

【The invention's effect】

The present invention is as described above, a uniform mixed slurry can be obtained by using a specific anionic copolymer aqueous emulsion, there is no layer separation, and the strength is excellent. It can manufacture a green body.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a process for manufacturing a lightweight ceramic, FIG. 2 is a sectional view showing a state of a separation layer when a mixture of clay, resin emulsion and water is allowed to stand, and FIG. 3 is clay and resin emulsion. FIG. 4 is a cross-sectional view showing a state of a separation layer when a mixed solution of water, water, and a breaking agent is allowed to stand.

Claims (1)

(57) [Claims] 1. A ceramic base powder (A) of 100 parts by weight, an anionic copolymer aqueous emulsion (B) of 3 to 50 parts by weight in terms of a solid content of a copolymer, an inorganic compound which generates ions in water ( A mixed solution containing 15 to 150 parts by weight of C) and an appropriate amount of water (D) is heated at a temperature higher than the glass transition point (Tg) of the copolymer in the aqueous emulsion of the component (B). ,
While maintaining the temperature at the transition point + 45 ° C. or lower, a chelate is formed by the ion derived from the compound of the component (C) and the anionic surfactant, and the formation of the chelate allows the emulsion copolymer of the component (B) to be formed. A method for producing a lightweight ceramic body molded body, comprising agglomerating particles to form a molded body holding the powder (A) and water, and then drying the molded body.