JPH02116662A - Pottery composition - Google Patents

Abstract

PURPOSE:To prolong a pot life of a pottery compsn. by specifying a components and amt. of an emulsion of a binder to be mixed with a powdery body for the pottery product. CONSTITUTION:A pottery compsn. is obtd. by mixing 100 pts.wt. (A) powdery body (potter's clay) for a material for a pottery product with 3-30 pts.wt. (B) (basing on solid content of resin) anionic aq. resin emulsion of an OH-group contg. acrylic copolymer prepd. by polymerizing 100 pts.wt. mixture of unsatd. monomers consisting of (a) 0.3-10% OH-group-contg. unsatd. monomer, (b) 40-55% alkyl acrylate (2-8C alkyl), (C) 30-55% monomer selected from methyl methacrylate, and acrylonitrile, (d) 1-10% unsatd. monomer selected from N- phenyl maleimide, N-methylol acrylamide, and (meth)acrylamide, and (e) 0-20% other unsatd. monomers, in the presence of 0.1-5 pts.wt. anionic emulsifier and 0-5 pts.wt. nonionic emulsifier. Thus, the pottery compsn. is obtd.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a composition for ceramics used for manufacturing ceramics.

[Conventional technology]

Traditionally, ceramic base powder (
Synthetic resin is added as a binder to china clay), and after mixing, press molding, extrusion molding,! A method is known in which the material is formed into a predetermined shape by 8-injection molding or the like, and then fired. In this case, it is desirable that the synthetic resin be completely decomposed at as low a temperature as possible during firing and be evaporated gently. For this purpose, especially methacrylic acid ester/α,β-unsaturated fatty acid copolymer (α,β-unsaturated fatty acid copolymer) The amount of unsaturated fatty acid to be used is 0.01 to 50 mol % in the copolymer component) particles or an aqueous emulsion or solution thereof has been proposed (see JP-A-61-251557). The emulsion of this binder has good infiltration and dispersibility with ceramic base powder, has strong adhesion, and has strong raw strength of the base, and can be used at low temperatures (400 to 450°C).
It decomposes completely and slowly, and has the advantage that no carbon or ash remains in the ceramic base obtained by firing. By the way, when styrene/acrylic acid alkyl ester copolymer aqueous emulsion, which is mainly composed of styrene, is fired. Styrene burns quickly and carbon tends to remain.

[Problem to be solved by the invention]

The base powder for ceramics, so-called china clay, is made of china clay such as pottery stone, feldspar, etc. of the kaolin group, montmorillonite group, mica group talc, pyrophyllite, jamonite, mudstone group, etc., and non-plastic raw materials such as silica stone and rouseki. In addition to general ceramic bases, glass frit, alumina, silicon nitride, magnesia, zirconia, beryllia, thoria, avinelle, cordierite, limestone, ferruginous jamonite, steatite, titanium oxide, Special ceramic bases such as barium titanate, Cersian, and ferrite are used. These china clays contain polyvalent metal ions such as Ca+1, Mg+", and Fe+". Therefore, JP-A-61
In the methacrylic acid ester/α,β-unsaturated fatty acid copolymer aqueous emulsion or aqueous solution disclosed in Publication No. 251557, the content of α,β-unsaturated fatty acids in the copolymer is 0.01 to 50 mol. %, it reacts with the polyvalent metal ions to form a chelate, increases in viscosity over time, and tends to aggregate or solidify on the surface of the china clay. For this reason, it is necessary to process (molding on a potter's wheel or press molding) as soon as possible after mixing with the ceramic base powder. Therefore, an object of the present invention is to provide a composition for ceramics that has good wettability and dispersibility, has high raw strength of the base material, and has a long pot life until molding and processing.

[Means for Solving the Problems J] In order to achieve the above object, in the present invention, an aqueous anionic resin emulsion of an acrylic copolymer having a hydroxyl group is used as a binder. That is, the ceramic composition characterized by the present invention is based on 100 parts by weight of the ceramic base powder (A). (a) Hydroxyl group-containing unsaturated monomer 0.3 to 10% by weight (b) Acrylic acid alkyl ester (alkyl group has 2 to 8 carbon atoms) 40 to 55% by weight (c) Selected from methyl methacrylate and acrylonitrile (d) 1 to 10% by weight of an unsaturated monomer selected from N-phenylmaleimide, N-methylolacrylamide, acrylamide, and methacrylamide (e) Other unsaturated monomers Hydroxyl groups obtained by emulsion polymerization of 100 parts by weight of an unsaturated monomer mixture consisting of 0 to 20 parts by weight of monomers in the presence of 0.1 to 5 parts by weight of an anionic emulsifier and 0 to 5 parts by weight of a nonionic emulsifier. The anionic resin aqueous emulsion (B) containing an acrylic copolymer is blended in a proportion of 3 to 30 parts by weight (resin solid content). In the above configuration, the ceramic base powder (A) is as follows:
The aforementioned kaolin, feldspar, silica, clay, bentonite, etc. can be used. On the other hand, in order to obtain the anionic resin aqueous emulsion (B) by emulsion polymerization, a polymerization catalyst such as a persulfate is used. The film-forming temperature of the emulsion is preferably 10°C or higher, preferably 15 to 25°C, from the viewpoint of avoiding stains due to stickiness and workability. 〇H) improves the infiltration and adhesion to the ceramic base powder, improves the dispersibility of the powder, and also improves the adhesion with the glaze applied on the base to be processed. Make it. For this same purpose, a copolymer emulsion having acid groups is generally used, but there is a limit to the amount used because the introduction of acid groups is affected by the aggregation effect of polyvalent metal ions in the ceramic base powder. Furthermore, each component of the anionic resin aqueous emulsion (B) will be described. As the hydroxyl group-containing unsaturated monomer of component (a), acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, pentaerythritol tetraacrylate, and diethyleglycol monoacrylate, and their methacrylate equivalents can be used. From the viewpoint of storage stability, pigment dispersibility, adhesion, and water resistance, this unsaturated monomer is used in a proportion of 0.3 to 10% by weight. Component (b), acrylic acid alkyl ester, is a soft monomer that gives flexibility to the film, including ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, n-propyl acrylate, and acrylic acid. 2-ethylhexyl and the like are used. Component (c), methyl methacrylate or acrylonitrile, is a hard monomer that imparts toughness to the film, and a portion thereof may be replaced with ethyl methacrylate, isopropyl methacrylate, or isobutyl methacrylate. The component (d), an unsaturated monomer having 100NH2 groups and methylol groups, is used to impart adhesion and dispersibility to the ceramic base powder. Other unsaturated monomers of component (e) include α such as acrylic acid, methacrylic acid, itaconic acid, and maleic anhydride.
, β-unsaturated carboxylic acid, styrene, ethylene, butadiene, etc. can be used. When α,β-unsaturated carboxylic acid is used, the amount of α, β-unsaturated carboxylic acid in the copolymer is
It is used in a proportion of 8×10-' mol % or less. In order to prevent viscosity increase and gelation when mixed with china clay, this anionic resin aqueous emulsion uses a hydroxyl group-containing unsaturated monomer (component (a) that provides a copolymer) in an amount of 0.3
-10% by weight binding, film adhesion, water resistance, strength, emulsion storage stability, and china clay dispersibility were good.
Further, the types and amounts of the other components (b), (c), (d) and (e) are selected so that the film forming temperature of the emulsion reaches the desired value. Next, the preparation of the composition and the manufacture of ceramics will be described. The main ingredients of china clay, which is the base powder for ceramics, are 5i02, AQ, and 03, and kaolin, clay, mica, feldspar, bentonite, silica, talc, etc. are used.After these are weighed and mixed, they are crushed using a crusher in water. Then, 3 to 30 parts by weight (resin solid content) of the emulsion were mixed with 100 parts by weight of this ceramic base powder and kneaded into clay.
It is defoamed (soil kneading process). This refined clay is molded into the desired shape using a plaster mold or on a potter's wheel, and then dried (forming process). Then, the dried molded product green material is finished with a smooth surface (green material finishing process) and then bound.
After being fired at a high temperature of 1,200 to 1,300°C (firing process), it is transferred to the glazing process.゛In addition, after applying raw glaze to the ceramic base (molded product base),
After aging at about 400°C, a pattern layer formed on the transfer paper is transferred thereon and further fired at about 500 to 1000°C to produce ceramics. Furthermore, a ceramic base is glazed with a mixture of a glaze and an aqueous anionic resin emulsion, and then a pattern for transfer is transferred by a water slide method, or an aqueous glaze dispersion is overcoated for decoration, and then fired. By doing so, it is possible to manufacture ceramics by performing glaze and pattern firing at the same time. Note that the step of forming the clay may be press forming or extrusion forming. The anionic resin aqueous emulsion burns or decomposes due to the heating during the compaction and firing steps, and there is no residue such as carbide in the ceramic. If the amount of the anionic resin water-based emulsion CB) is less than 3 parts by weight in terms of solid content per 100 parts by weight of the ceramic base powder (A), the infiltration of the emulsion will be poor, and
Powder dispersibility is also poor. Furthermore, the molding process is difficult to work with, and the resulting ceramics may crack or become brittle. On the other hand, if the solid content exceeds 30 parts by weight, the weight loss after firing will be large, resulting in a rough green material. [Function] The copolymer of component (B) in the present invention has good infiltration and dispersibility with respect to the ceramic base powder, is easy to mold, has strong adhesive strength as a binder, and has good adhesion to the base powder for ceramics. It has high green strength, decomposes completely and gently at low temperatures (400 to 500°C), and moreover, carbon and ash are unlikely to remain in the ceramic base obtained by firing. Furthermore, since the pot life of the ceramic composition is long, a large amount of kneaded ceramic base can be prepared and mass production of ceramics is possible.

[Implementation examples, etc.]

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts and percentages in the examples are based on weight unless otherwise specified. Emulsion production example 1 Temperature controller, anchor stirrer, reflux condenser, supply container,
The following raw materials were charged into a reaction vessel equipped with a thermometer and a nitrogen inlet tube. water 2
00 parts 35% aqueous solution of the sodium salt of the sulfuric acid half ester of p-nonylphenol (anionic emulsifier) reacted with 20 moles of ethylene oxide 5 parts 20% solution of p-nonylphenol (nonionic emulsifier) reacted with 25 moles of ethylene oxide Then, after purging the reaction vessel with nitrogen gas, 10% of the feed I shown below was added and heated to 90°C. Supplies! water 2
00 parts 35% aqueous solution of the above anionic emulsifier 25 parts Methyl methacrylate 195 parts n-butyl acrylate 189 parts 2-hydroxypropyl acrylate
2 parts Acrylamide 8 parts Furthermore, after charging 10% of 2.5 parts of potassium persulfate dissolved in 85 parts of water (feed ■) into the reaction vessel, the remaining feed!
All and 90% of Feed I was fed into the reaction vessel over 3.5 hours, and after the feed was completed, the same temperature was maintained for 2 hours to polymerize Feed I to obtain an aqueous anionic resin emulsion. Emulsion Production Examples 2 to 12 Anionic resin aqueous emulsions were obtained in the same manner as in Production Example 1, except that the composition of the unsaturated monomer was changed as shown in Table 1 below. However, in Example 7, the amount of anionic emulsifier used was 0.05% by weight of the unsaturated monomer and 8% by weight in Example 8. Example 1 Pottery stone 47%, feldspar 6%, silica 10% as a base for ceramics
To 100 parts by weight of a base powder of 22% Frogme clay and 15% Honbushi clay, 20 parts by weight of the anionic resin aqueous emulsion with a solid content concentration of 50% obtained in Production Example 1 was added and kneaded. After mixing, the pot life of this mixture is 40℃
It was over 10 days. The kneaded mixture was then molded using an It/cJ press, and then fired at 1300°C to obtain porcelain tiles measuring 10 cm long, 10 pieces wide, and 3 mm thick. This product has good dispersibility of the base powder, strong green strength after press molding, easy handling, and excellent workability.Even after firing, there is no occurrence of deformation, collapse, or cracking, and carbide remains. There was no problem and the product was good. Examples 2 to 5, Comparative Examples 1 to 3 Porcelain tiles having the physical properties shown in Table 2 below were prepared in the same manner as in Example 1, except that the emulsions of Production Examples 2 to 8 were used instead of the emulsions of Production Example 1. Obtained. Examples 6-7, Comparative Examples 4-5 Porcelain tiles having the physical properties shown in Table 2 were obtained in the same manner as in Example 1, except that the amount of emulsion was changed as shown in Table 2 below. (Hereinafter, this page margin) Application example Add 70 parts by weight of water to 100 parts by weight of commercially available lead glaze, grind and mix in a ball mill (solids approximately 58%, pH 9.3).
) Make a dispersed glaze liquid, add 100 parts by weight of this dispersed glaze liquid,
10 parts by weight of the anionic resin aqueous emulsion (solid content 50% by weight, pH 6.0) obtained in Production Example 1 was blended to prepare a raw glaze. Rouseki 35 is used as a base powder for ceramics.
%, 15% feldspar, 40% frog's eye clay, and 10% silica powder were mixed with 30 parts by weight of the anionic resin aqueous emulsion of Production Example 1, formed into a slurry, cast and molded at 1200°C. Spray and paint the raw glaze that has been prepared for one day on the surface of the fired ceramic unglazed plate, 15
After pre-driing the glaze at 0°C, a pattern layer printed on transfer paper was transferred onto the surface of this raw glaze layer using the water slide method, and the plate with this decoration was fired for a second time (glaze firing) at 1250°C. The pattern was in good condition with a single outline and no fading or pinholes in the glaze.

【Effect of the invention】

The present invention is as described above, and can completely prevent deformation, collapse, cracking, etc. of the substrate due to insufficient thermal decomposition of the binder, the contamination of ash, and the sudden generation of decomposed gas, and can form thick walls. Even in these cases, ceramics with excellent appearance, performance, strength, etc. can be obtained. Further, since the base powder in the composition is well dispersed, it has excellent moldability, and even delicate and complicated shapes can be molded with high precision.

Claims (1)

[Scope of Claims] Based on 100 parts by weight of ceramic base powder (A), (a) 0.3 to 10% by weight of hydroxyl group-containing unsaturated monomer (b) Acrylic acid alkyl ester (the number of carbon atoms in the alkyl group is 2-8) 40-55% by weight (c) 30-55% by weight of a monomer selected from methyl methacrylate and acrylonitrile (d) Selected from N-phenylmaleimide, N-methylolacrylamide, acrylamide, and methacrylamide 100 parts by weight of an unsaturated monomer mixture consisting of 1 to 10% by weight of unsaturated monomers (e) 0 to 20% by weight of other unsaturated monomers, and 0.1 to 5 parts by weight of an anionic emulsifier and a nonionic emulsifier. Anionic resin aqueous emulsion (B) of an acrylic copolymer containing hydroxyl groups obtained by emulsion polymerization in the presence of 0 to 5 parts by weight of an emulsifier is blended at a ratio of 3 to 30 parts by weight (resin solid content). A composition for ceramics characterized by comprising: