KR910001349B1 - Method for producing ceramic products - Google Patents

Abstract

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Description

Manufacturing method of cast ceramic product

The present invention relates to a composition for forming a ceramic, a method for forming a ceramic using the same, and a method for processing a molded body. In more detail, the present invention relates to ceramics or ceramic sojito [herein, so-called neo-ceramic sojito, such as ceramic sojitoran alumina, zirconia, silica, ferrite, silicon carbide, silicon nitride or sialon and the like. Means to add a hand-emulsion to a ceramic molding composition, a method of molding a ceramic from the composition, and attaching the bonding medium of the molding from two or more moldings obtained by the above method, and then firing the bonding medium. It relates to a molding processing method of a ceramic.

In the conventional molding slip casting method of ceramics, water, peptizing agent, etc. are added to small pieces of soil to prepare a slip, and the slip is introduced into a mold such as a gypsum mold, which is absorbed, and absorbed by the mold. Injection moldings have been formed by enhancing adhesion of ceramic particles on the mold surface and demolding after the ceramic particles have been completely strengthened. The molded product is then made into a ceramic product through processes such as drying, roasting, glazing and firing. However, in this case, the molded product is mechanically resistant to a degree that can be sufficiently tolerated in the processing such as finishing processing and transportation. You must have a robbery. It is inevitable that they can be easily demolded from their corresponding molds.

Conventionally, in order to give the mechanical strength required for the progress of slip casting during slip casting with sojito, it has been carried out by containing a large amount of gyro-clay, kibushi-clay, and the like. But. Castings made of such clay are required to give sufficient mechanical strength by preliminary roasting, and the use of clay is difficult to produce high-quality porcelain with transparency such as white porcelain, and also due to the depletion of quality clay resources. You face a difficult problem. For this reason, there has been a great demand for the development of a strength improving agent capable of imparting sufficient mechanical strength to a cast product without using a large amount of clay.

On the other hand, even if the conventional ceramic moldings can never be used in the industrial field, new ceramic products have been expected to find utility in the industrial field because of their excellent mechanical strength, heat resistance, abrasion resistance, and the like. However, under current conditions, their application cannot be said to proceed as expected. One of the main reasons for the limited application of new ceramic products can be said to be the difficulty of forming and processing processes.

Various molding methods have been proposed for molding ceramic products, including the slip casting method described above.

Using such a molding method, even a molded article having a complicated appearance can be easily obtained. In the case of new ceramics, their shaping should depend on sheet forming, extrusion, compression molding and the like. Therefore, it is not easy to obtain a complicated appearance product. In other words, these molding methods are only possible to provide products of simple appearance, such as plate-like products, tubular products, and the like. Therefore, as long as the slip mold can be applied to a new ceramic material, a complicated appearance product can be formed from them. However, it is impossible to form a cast product of sufficient strength when the ordinary sogi is applied as it is. Thus, there is an urgent need for improvement of strength enhancers that impart sufficient mechanical strength to cast products for successful handling during final processing and transportation.

The present inventors have studied extensively to solve the above problems. As a result, it was found that by using a resin emulsion as a strength enhancer, the mechanical strength of the cast product can be improved, whether used in ceramic earthenware or ceramic earthenware.

By the above-described method, it is possible to obtain new ceramic products of various shapes in addition to plate and tubular products. In order to obtain cast products of more complex appearance, two or more cast products were separated and partially molded by the above-described method, and these were joined with an adhesive, and then an attempt was made to fire the thus joined casting products. However, using any conventionally known adhesive is impossible to obtain the desired product, since these adhesives decompose upon firing and the bonded cast product separates it from the joint surface.

However, the present inventors bonded the above-described cast product with a ceramic medium and a resin emulsion instead of a conventionally known adhesive, and fired the thus-joined cast product, thereby performing a ceramic of a desired shape without performing the aforementioned separation. It has been found that a product can be obtained to complete the present invention.

The first object of the present invention is to form a cast product having a degree of mechanical strength that can be successfully performed in the casting of slips of porcelain or ceramic soil, and can be successfully finished without the need for basic roasting. It is to provide a slip composition that can be, and also to provide a slip casting method using such a composition.

A second object of the present invention is to provide a slip composition capable of achieving the first object of the present invention without using a large amount of clay component as a porcelain of porcelain in casting slip of sojito. It is to provide a casting method.

The third object of the present invention is to provide a slip composition that can be applied to ceramic sods, in addition to providing a slip casting method to impart sufficient mechanical strength to the molded casting product so that it can be successfully processed during finishing and transportation. It is to provide a slip casting method.

It is a fourth object of the present invention to provide a method for producing a new ceramic product having a complex appearance from ceramic raw materials which are basic raw material holding materials.

The above object of the present invention is achieved by the following aspects.

1. A ceramic molding composition formed by mixing a slip containing ceramic porcelain or ceramic clay as a main component with a resin emulsion.

2. Ceramic molding method characterized by slip casting the slip composition.

3. A) A slip containing ceramic earth as a main component is mixed into a resin emulsion to make a slip composition, and B) two or more cast products are formed from a slip composition according to the slip molding method, wherein the cast product is Bonding relations such that they have the same or different appearance and have at least one set of joining surfaces to which each of the cast articles will be bonded.) C) Bonding at least one side of the cast article with a bonding medium containing ceramic substrate and resin emulsion as the main component. Applying to the surface, and D) joining the joint surfaces of the cast products to join the cast products into an integrated cast product, and E) firing the integrated cast product.

Although the slip casting method of the present invention can produce a highly complicated new ceramic molded article, the new complicated ceramic article of the desired complicated external shape is applied to a processing method of a cast product, which is characterized by a series of processes described in the above paragraph 3. Under the condition of the present invention can be obtained according to the slip casting method of the present invention.

Before use herein, "pottery sojito" means sojito which is commonly used as porcelain sojito, and these sojito are feldspar and quartzite as its main components or ingredients. Toseki (magnet), kaolin and / or clay and the like.

Meanwhile, "ceramic sojito" means a raw material of ceramic, and metal oxides such as alumina, zirconia, ferrite, silica, beryllia, magnesia, titania, calssia and zinc oxide, and silicon carbide Carbides such as boron carbide, nitrides such as silicon nitride, aluminum nitride and boron nitride, borides such as aluminum boride, silicates, aluminates, zirconates, barium titanates and strontium titanates of various metals, Solid solution such as sialon and mixtures thereof.

The "resin emulsion" is, for example, an acrylic resin containing (meth) acrylic acid ester resin, (meth) acrylic acid ester-vinylacetate resin, (meth) acrylic acid ester-styrene resin or (meth) acrylic acid ester-vinylchloride resin as main components. Emulsion of vinyl acetate resin containing vinyl acetate resin as main component, emulsion of ethylene copolymer containing ethylene-acrylic acid ester resin or ethylene-vinyl chloride resin as main component, styrene-butadiene resin and methyl methacryl Synthetic rubber emulsion, natural rubber emulsion, etc. containing a late butadiene resin or an acrylonitrile butadiene resin are mentioned. Of these resin emulsions, emulsions of acrylic resins are preferred.

The amount of the resin emulsion to be added to the porcelain or ceramic soil is varied depending on the kind of porcelain or ceramic soil, its particle size and particle size distribution, the kind of resin emulsion, the kind of ceramic product to be formed, and the like. So you can't talk about usage uniformly. In general, however, it is appropriate to add to the resin emulsion in an amount of about 0.1 to 20 parts by weight as the solids of the emulsion per 100 parts by weight of dried ceramics or ceramics.

The resin emulsions used in the practice of the present invention can be prepared by emulsion polymerization known in the art. That is, after dispersing the corresponding monomers in a mixed solvent of water or a water-soluble organic solvent such as acetone as water and a medium (adding a surfactant as needed to homogenize the medium), the water-soluble radical polymerization initiator and Can be prepared by emulsion polymerizing monomers in the presence of molecular weight modifiers and other chemical additives.

As the polymerization initiator, conventional radical polymerization initiators such as peroxides, redox catalysts, persulfate salts or azo compounds can be used.

If a surfactant is used, any one of anionic, cationic, nonionic and zwitterionic surfactants or a combination of combinations of these surfactants may be used. As the molecular weight modifier, mercaptans such as t-dodecyl mercaptan or n-dodecyl mercaptan, carbon tetrachloride isopropyl alcohol and the like can be used.

The polymerization can generally be carried out at 40-90 ° C. in a reactor deoxygenated. Monomers, surfactants, molecular weight modifiers, polymerization initiators and other chemical additives may all be added to the reaction medium at the beginning of the reaction. Some or all of these may be added in small portions after the start of the reaction. It is also possible to change operating conditions such as temperature and stirring conditions required in the reaction path. The polymerization reaction may be carried out continuously or in batches.

The slip composition of the present invention, prepared by adding a resin emulsion to porcelain or ceramic soil, is very stable and has a low viscosity and good flowability, ie good formability. Products formed from slip compositions have good mechanical strength.

Slips containing porcelain or ceramic soybean as a main component and used in the preparation of the ceramic molding composition of the present invention, wherein at least one deflocculant, sintering agent, other than the above-described porcelain or ceramic soybean, Other ceramic raw materials, additives and the like may be added as necessary.

Examples of peptizing agents include inorganic peptizers such as water glass, sodium carbonate and phosphates such as sodium phosphate and sodium tripolyphosphate and organic peptizers such as sodium polyacrylate, naphthalenesulfonic acid-formaldehyde condensation products and sodium lignin sulfonate . These aliquots are generally from 0.02 to 2 parts by weight of solids per 100 parts by weight of dried ceramics or ceramics.

Examples of the sintering agent include oxides of rare earth metals such as magnesia, boron, yttrium, tantalum and the like. Its usage amount is 0.01 to 5.0 parts by weight per 100 parts by weight of dry porcelain or ceramic sojito.

As additives other than those mentioned above, release agents such as calcium stearate, zinc stearate and wax emulsions, pH adjusting agents such as organic amines such as ammonia and triethanolamine, organic acids such as oxalic acid and formic acid, silicone-base and polyether-based defoamers Defoamer is mentioned. These amounts are 0.01 to 10 parts by weight of solids per 100 parts by weight of dried ceramic or ceramic soil, respectively. In addition, a hydrating agent, an ion trapping agent plasticizer such as a chelating agent, etc. may be used as needed.

In the ceramic molding composition of the present invention, porcelain or ceramic earthenware amounts to 40 to 85 parts by weight as a solid per 100 parts by weight of the ceramic molding composition.

Each cast product molded in accordance with the method of the present invention has a green strength that can withstand handling and post-processing operations sufficiently without the need for an initial roasting process. Thus, glazing and firing are performed to produce cast ceramic products without the need for rough roasting. If necessary, the cast product may be colored, glazed, calcined, glazed and decorative fired. The composition of the present invention shows excellent results not only in the slip casting method but also in the extrusion process jiggering process, the jolleing process, the potters wheeling process and the like.

As described above, the present invention exhibits the following excellent effects: 1) The initial roasting process can be omitted. 2) Easy post processing. 3) When ceramic porcelain is used, the clay component may be omitted or reduced. 4) Slip casting can be applied to ceramic sods, which can result in more complex new ceramic products. 5) Provide cast products with enhanced wet strength.

According to the present invention, in order to obtain a new ceramic product having a complex appearance, it is necessary to apply a processing step including the continuous steps A to E described above. Among these continuous processes, the A and B processes are the same as those described above for ceramic earth. Therefore, step C and subsequent steps are described in detail below.

That is, two or more new ceramic products molded through the A and B processes are applied to the surface to be bonded to each other with a bonding medium of the C process.

Joined in the process to form an integral cast product. If the bonding medium used in step C is anything other than that used in the practice of the present invention, the strength of the bonding portion is insufficient even after its firing. The product thus separates at the junction in use.

In the present invention, the bonding medium contains, as its main component, ceramic earthenware and a resin emulsion.

As an example of the ceramic material which comprises a joining medium, it is the same as that of the new ceramic material as mentioned above. Any of such new ceramics may be used. Although it is not absolutely necessary to use the same new ceramic sojito as used in process A, it is preferred to use the same new ceramic sojito. In general, ceramic earthenware contains fine ceramic earthenware having a small particle size of about 100 microns and a fairly coarse ceramic earthenite having a large particle size of about 5 mm. In the case of such coarse ceramic soil, it is preferable to use it by pulverizing to a desired size.

Examples of the resin emulsion which is another component of the bonding medium include the same ones as the resin emulsion described above. Any of such emulsions can be used. It is not absolutely necessary to use the same resin emulsion as used in step A, but here again, an emulsion of an acrylic resin is preferred. Two or more resin emulsions of different kinds may be used in combination.

The adhesive contains the above-mentioned ceramic resinous earth and a resin emulsion. Prior to its use, it may be dispersed in a dispersion medium as necessary. As a dispersion medium, water is preferable.

The amount of resin emulsion to be added to the ceramic clay depends on the type of ceramic clay, the type of resin, and the type of cast ceramic product to be produced. It is appropriate to add the resin emulsion by about 0.1 to 20 parts by weight.

The preferred proportion of ceramic substrate in the bonding medium is in the range of 20 to 90 per 100 parts by weight of the bonding medium.

The bonding medium thus obtained is applied to the surface of the cast product made through steps A and B (they were to be joined together). Here, it is preferable to wet the bonding portion of the product to be bonded with the same dispersion medium as contained in the bonding medium before using the bonding medium. Otherwise, the dispersion medium in the bonding medium causes the cast product to move, resulting in a reduction in the bond strength of the final product obtained after firing. Bonding media can be applied to both sides of the joint, but applying only one side is not a problem or inconvenience. Although there is no particular limitation on the amount of bonding medium to be applied, it is generally preferable to apply it as uniformly as possible with a coating thickness of 0.1 to 5 mm, and it is used as a conventional method such as a trowel. The cast articles coated with the bonding medium on the drawings to be joined are bonded together in step D, and then fired in step E under conditions appropriate to the ceramic material used to produce the desired ceramic product. As the firing conditions of the step E, the firing temperature is generally 1000 to 2500 ° C., the firing time is usually 0.1 to 200 hours, and the firing gas is usually air, but there are problems and disadvantages even when using an inert gas such as nitrogen. none.

Unlike conventional magnetic products, new ceramics are difficult to make as described above. In other words, since the lack of suitable binders for new ceramics, the resulting products have low strength before firing. Considering the various properties required for new ceramics, it was practically impossible to join and fire two or more cast products.

According to the present invention, a cast product having improved wet strength can be produced by slip casting by combining a resin emulsion with a slip containing ceramic soji as a main component. In addition, after bonding two or more cast products with a specific bonding medium, after firing, it is possible to obtain a new ceramic product having a complicated shape without reducing various properties according to mechanical strength. When slip casting the ceramic-generating composition of the present invention in gypsum molds, the demolding properties of the composition are important properties that determine whether slip casting can be successfully performed. The term " deformation property " here refers to the property that the cast product is easily demolded when demolded from the gypsum mold, and whether cutting or deformation occurs.

In order to have good demolding characteristics, the adhesive strength between the mold and the corresponding cast product is weak, the strength at the time of demolding of the slip cast product, that is, the wet strength is sufficiently high, and during the finishing work and movement of the cast product after demolding from the mold, and the subsequent drying It is considered necessary to have sufficient dry strength to withstand the handling of.

The demolding properties are related to two variables: the first variable is the wet strength of the slip cast product, and the second variable is the adhesive strength of the interface between the mold and the ceramic soil, that is, the force required to separate the slip cast product from the mold surface. Hereinafter referred to as "deformation strength"). This demolding strength is known to vary considerably with the type and amount of peptizing agent added to sojito. It is also known that the use of slip having good demolding properties significantly reduces the wall thickness of gypsum molds, i.e., the gypsum molds deteriorate more than when demolding from their rising cast products. In other words, the better the demolding properties of the slip, the shorter the service life of the gypsum mold. One of the reasons for this tendency is that the peptizing agent reacts with the gypsum mold at the interface of the gypsum mold so that the reactant weakens the adhesive strength between the surfaces, but the surface layer of the mold is destroyed by the reaction.

In order to solve the above problem, a method of adding a wax-based emulsion to ceramics and ceramics has been proposed, but using such an emulsion is still insufficient to solve the problem.

As a method of improving the wet strength of the cast product, water-soluble natural polymer materials such as gum acacia, sodium alginate, water-soluble semi-synthetic polymer materials such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose and carboxymethyl cellulose, and Various studies have been conducted, such as adding water-soluble polymer materials such as water-soluble synthetic polymers such as polyvinyl alcohol and water-soluble acrylic polymers. In slip casting, the water-soluble polymer moves with water due to its inherent property, so that the water-soluble polymer moves with water to the surface layer of the gypsum mold. Therefore, the quality of the surface of the mold is degraded or fine pores of the mold surface are aggregated. For this reason, the service life of the mold is shortened.

During the subsequent casting of the slip cast or the resulting cast product, moisture migrates to the cast product surface. Thus, when slip casting, water is absorbed from the cast product surface to the corresponding gypsum mold. In the drying process, water is evaporated from the surface of the cast product. As described above, since the water-soluble polymer material moves with water, water-soluble polymer material gathers near the cast product surface while hardly exists near the center of the cast product, so that the cast product is hard only near the surface. Due to this non-uniformity of the force, there is a fear that the ceramic product may be warped or cracked after firing or sintering.

However, as a resin emulsion when making a composition for ceramic molding suitable for slip casting, it is as follows: A) 0.1 to 15% by weight of carboxyl-containing monomer units and / or B) substituted or unsubstituted with the following general formula: Carbamoyl-containing monomer unit 0.1 to 5% by weight:

[Wherein R ₁ and R ₂ are the same or different and each represent a hydrogen atom or a methyl group, and R ₃ represents a hydrogen atom, a C ₁ -C ₄ alkyl group or a hydroxymethylene or alkoxymethylene group having the general formula:

CH ₂ OR ₄

(Wherein R ₄ means a hydrogen atom or a C ₁ -C ₄ alkyl group): and C) a specific composition consisting of 85-99.9% by weight of one or more monomer units copolymerizable with the monomers A) and / or B). When the aqueous emulsion of the copolymer is added to the slip according to the invention, which contains porcelain or ceramic sojito as the main component, the use of an aqueous resin emulsion not only increases the mechanical strength of the mold soji, but also surprisingly improves the demolding properties and It has been found to extend the life of the plaster model.

Preferred examples of the carboxyl-containing monomer (hereinafter referred to as "monomer A") in the monomer unit constituting the specific copolymer are acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid and maleic acid, and ita Monoalkyl esters of choline and maleic acid. The proportion of such monomers in the copolymer component unit is about 0.1 to 15% by weight, preferably about 2 to 10% by weight. If the ratio is 15% by weight or more, the viscosity of the slip is so high that the fluidity deteriorates and a good cast product cannot be formed when an aqueous emulsion is added to the slip. On the other hand, if it is less than 0.1% by weight, it is not possible to mold a cast product having sufficient wet strength.

Preferred examples of the substituted or unsubstituted carbamoyl-containing monomer (hereinafter referred to as "monomer B") in the monomer unit constituting the specific copolymer described above are acrylamide, methacrylamide, dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, methoxymethylol (meth) acrylamide, butoxymethylol (meth) acrylamide, etc. are mentioned. The proportion of such monomers in the copolymer component unit is preferably 0.1 to 5% by weight, preferably 0.5 to 4% by weight. If the ratio is 5% by weight or more, the viscosity of the slip becomes high and the viscosity increases with time, and the fluidity is weakened when an aqueous emulsion is added to the slip. Therefore, it is impossible to stably mold high quality cast products. On the other hand, if the ratio is 0.1% by weight or less, it is impossible to mold a cast product having sufficient wet strength.

When using a combination of monomers A and B as constituent monomer units of the copolymer, the total proportion of these two monomers should be 0.1 to 15% by weight of the copolymer constituent monomers, and the proportion of each monomer should be within the respective ranges described above.

As monomers copolymerizable with monomer A and / or monomer B (hereinafter referred to as "monomer C"), hydroxyl-containing monomers can be used, and specific examples of such hydroxyl-containing monomers are 2-hydroxyethyl Acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate and the like. In the case where the amount of such monomers used as component units in the copolymer is 0.2 to 10% by weight, adding the copolymer thus produced to the slip lowers the viscosity of the slip, has good fluidity, and long-term stability of the viscosity (i.e., over time). Viscosity does not increase). If it is used more than 10% by weight, the demolding property during slip casting is degraded and the plaster mold is entangled, which shortens the life of the plaster mold. Therefore, it is not preferable to use monomer C outside the above range.

In addition to the above-mentioned compounds as the monomer C, for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, cyclohexyl Acrylic esters such as acrylate and furfuryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methoxyethyl methacrylate, ethoxy methacrylate, butoxyethyl methacrylate and benzyl methacrylate Methacrylic ester like a rate; Aromatic vinyl monomers such as styrene, α-methylstyrene and para-methylstyrene; Vinyl esters such as vinyl acetate and vinyl propionate; Nitriles such as acrylonitrile and methacrylonitrile; And vinyl chloride, ethylene, butadiene, etc. can also be used.

An aqueous emulsion of a particular copolymer is an emulsion of a copolymer containing monomers C as a main component, as described above. Preferred aqueous emulsions are, in particular, copolymers obtained by copolymerization reaction using an acrylic ester, styrene-acrylic ester mixture, styrene-butadiene mixture, methyl methacrylate-butadiene mixture or styrene-methylmethacrylate-butadiene mixture as monomer C. Aqueous emulsion of is mentioned.

When the surfactant is added to the aqueous emulsion of the specific copolymer, the amount is preferably limited to 1.0% by weight or less based on the total weight of the monomers. The emulsion of the polymer particles is preferably 0.05 to 0.6 mu m, particularly 0.1 to 0.25 mu m. If the amount of the surfactant is 1% by weight or more, or the particle size of the emulsion is 0.6 µm or more, when the aqueous emulsion is added to the slip, the viscosity of the slip decreases, but the excellent mold release properties and the gypsum mold of the resulting cast product The effect of prolonging the lifespan is not sufficiently exerted. On the other hand, if the particle size of the emulsion is 0.05 µm or less, the slip added with such an aqueous emulsion has a high viscosity and thus decreases fluidity.

Ceramic molding compositions made by adding an aqueous emulsion of a specific copolymer to a slip containing porcelain sojito or ceramic sojito as a coarse component are quite stable, have low viscosity and good fluidity. In other words, it has excellent moldability. The resulting molded or cast product has good mechanical strength. Moreover, when the composition is used in the form of slips, in particular during mold casting, the demolding properties are improved while at the same time the life of the slip casting gypsum molds is significantly extended.

The above-mentioned excellent effect of the present composition using an aqueous emulsion of a specific copolymer is that a kind of interaction between the inorganic particles of porcelain or ceramics and the copolymer droplet of the aqueous emulsion proceeds in the composition so that the copolymer particles are inorganic particles. It is believed to be due to the fact that it is absorbed into. This implies two phenomena:

In a first phenomenon, solids concentration was diluted to about 50-70% by adding water to the composition, ie slip. When the diluted slip was left for 3 days to 1 week, a colorless clear water layer formed as a supernatant. The water layer contained almost no emulsion particles. It is assumed that the polymer particles of the emulsion were absorbed by the inorganic particles and thus precipitated together with the inorganic particles. On the other hand, similar slips were made using copolymer aqueous emulsions other than the aqueous emulsion of certain copolymers, ie, aqueous emulsions of homopolymers or copolymers that do not contain monomers A and / or monomer B as component monomer units. A similar test was made on this slip. Leaving this slip, the water layer produced by the supernatant was not cloudy and clear. It still contained significant amounts of polymer particles in the emulsion.

In a second phenomenon, a composition using an aqueous emulsion of a specific copolymer was pressed with a filter press. Colorless clear water actually oozed out. The water thus obtained did not contain the polymer particles of the emulsion. On the other hand, an aqueous emulsion of a copolymer in addition to the aqueous emulsion of a specific copolymer. That is, similar slips were made using aqueous emulsions of homopolymers or copolymers that did not contain monomer A and / or monomer B as component monomer units. When this slip composition is crimped with a filter press. Cloudy, unclear water containing significant amounts of polymer particles in the emulsion oozed out.

As suggested by the above phenomenon, the carboxyl group and / or alkoxy contained in the polymer particles, although the mechanism of interaction between the droplets of the specific copolymer of the aqueous emulsion of the inorganic particles of the porcelain or earthenware are not fully understood. Methylene groups may cause polymer particles to be absorbed into inorganic particles.

Next, the present invention will be described in detail by way of examples. Needless to say, the following examples illustrate only a part of the invention. In the examples, "%" and "parts" refer to parts by weight, respectively.

Example 1

Using clay clay sojito (Marui Paint Co., Ltd.) as a ceramic body, add 1 glass of water equivalent to 0.41% of dry solids of sojito, and add more water. Mixing and stirring with addition gives a slip having a solids content of 68.4%. Resin emulsion A (acrylic resin emulsion containing copolymer obtained from styrene and 2-ethylhexyl acrylate as the main monomer component; solid content: 43%) and B (styrene as the main monomer component) as shown in Table 1 on each slip. And a carboxyl-modified acrylic resin emulsion containing a copolymer obtained from 2-ethylhexyl acrylate; solids: 43%), C (copolymer obtained from main monomer component, styrene, methyl methacrylate and butadiene) Rubber emulsion; solid content: 43%) and D (vinylacetate resin emulsion containing polyvinyl acetate as the main monomer component; solid content: 43%) are added. The resulting mixture is mixed and stirred to obtain a uniform slip.

Each slip is poured into a gypsum mold, each 90 mm long, 20 mm wide and 5 mm thick. After the slip is left until a deposit of ceramic particles is formed on the surface of the corresponding mold, the molded cast product is demolded from the gypsum mold. The castings having the dry flexural strength shown in Table 1 are obtained by drying at room temperature and 110 ° C, respectively. Next, the slip cast product is fired to obtain an excellent ceramic product. Bending strength is measured using "Tensilon UTM-III-500" (trade name, manufactured by Toyo-Baldwin).

TABLE 1

On the other hand, slip casting is carried out without adding any resin emulsion. The resulting cast product is first roasted at 800 ° C. The flexural strength of the first roasted product is 36 kgf / cm 2.

Example 2

As clay porcelain, water glass 1 (0.26%) was added to clay-containing sojito (Marui Paint Co., Ltd., No. 30) based on the dry solid content of sojito. A slip with a solid content is obtained. Resin emulsion A used in Example 1 was added to each slip as shown in Table 2 to obtain a cast product in the same manner as in Example 1. Next, these are dried to obtain a cast product having a dry bending strength shown in Table 2. It is possible to fire the cast product to obtain an excellent ceramic product.

TABLE 2

On the other hand, slip casting is carried out without adding a resin emulsion at all. The resulting cast product is first roasted at 800 ° C. The dry flexural strength of the roasted product is 41 kgf / cm 2.

Example 3

5 kg of aluminum powder ("A-l6SG", trade name; manufactured by ALCO) and 5 kg of aluminum powder ("A-32", trade name; manufactured by Nippon Light Metal Co., Ltd.) are weighed to obtain a 10 kg aluminum powder mixture. The aluminum powder mixture is added 60 g of peptizing agent ("Seruna D-305", trade name; manufactured by Chuo-O-Yushi Kabushiki Kaisha) and water. The resulting mixture is stirred to obtain a slip having a solids content of 81.4%.

In each slip, the resin emulsions A, B, C and D used in Example 1 and the resin emulsion E (acrylic resin emulsion containing a polymer obtained from n-butyl methacrylate as the main monomer component; solid content: 43%) were used. Each is added as shown in Table 3. A cast product is obtained in the same manner as in Example 1 and dried to obtain a cast product having a dry bending strength shown in Table 3. The cast product may be fired to obtain an excellent ceramic product.

TABLE 3

Example 4

To the silica (silica from China) is added a peptizing agent ("Ceruna D-305", trade name; manufactured by Chuo-O-Yu Kabushiki Kaisha Co., Ltd.) in an amount equivalent to 0.6% based on the dry solid content of the ceramic material. Water is added to the resulting mixture and stirred to obtain a slip having 68.9% solids. To each slip is added the resin emulsions B, C and D used in Table 1 as shown in Table 4. The method of Example 1 is carried out to obtain a cast product. By drying this, a cast product having a dry bending strength shown in Table 4 is obtained.

TABLE 4

Example 5

To 10 kg of zirconia ("TZ-3Y", trade name; manufactured by Toureda Co., Ltd.), 200 g of a peptizing agent ("Ceruna D-305", trade name; manufactured by Chuo-Oyu-shi Kabushiki Kaisha) and water was added to give 71.4% solids. Get slip. To each slip are added the resin emulsions A and D used in Example 1 as shown in Table 5. The method of Example 1 is carried out to obtain a cast product. This was dried to obtain a cast product having the dry flexural strength shown in Table 5. By firing the cast product, an excellent ceramic product can be obtained.

TABLE 5

Example 6

1000 g of β-type silicon carbide powder ("Betarundium Ulcrapine", trade name; manufactured by Ibiden Co., Ltd.), 3 g of boron (manufactured by Mitsuwa Chemical Co., Ltd.), 3 g of peptizing agent ("SMA 144OH", trade name; ARCO Chemicals Co., Ltd .; Ammonium salt of the styrene-monoester copolymer of maleic acid), 10 g of 70% aqueous monoethylamine solution (manufactured by Kishita Chemical Co., Ltd.) and water are added to obtain a slip having a solid content of 65%.

The resin emulsion A used in Example 1 is added to the slip as shown in Table 6. The method of Example 1 is carried out to obtain a cast product. It is heated to obtain a cast product having the dry flexural strength shown in Table 6.

TABLE 6

Example 7

A cast product is obtained in the same manner as in Example 6, except that 100 g of a phenol resin emulsion (the ratio of water of formaldehyde to phenol is 2, solid content: 50%) is used in the production of slips. Next, it is sintered at 2120 ° C. to obtain a sintered product having a density corresponding to 98% of theory.

Example 8

1000 g of abrasive iron oxide powder ("NSK-500", trade name: Morishita Bengara Kogyo Co., Ltd.), 20 g of peptizing agent ("SN Dispersant 5020", trade name; product of Sun Nopko Co., Ltd.) and Water is added, the resulting mixture is stirred to obtain a slip having a solid content of 70%.

To each slip is added the resin emulsions A. C and D used in Example 1 as shown in Table 7. The method of Example 1 is carried out to obtain a cast product. This was dried to obtain a cast product having the dry flexural strength shown in Table 7.

TABLE 7

Example 9

A slip having 81.4% solids is obtained by carrying out the same production method as in Example 3 using the same raw materials as described in Example 3.

The acrylic resin emulsion F prepared according to the preparation method described below is subjected to slip in an amount of 3% of the dry ceramic material. The resulting mixture is stirred to obtain a uniform slip. The slip is poured into the gypsum mold and left to stand for 0.5 hours to form deposits of ceramic particles on the mold wall. The resulting cast product was demolded from the mold and dried at 110 ° C. for 1 hour to obtain a cup molded product. The cast product has sufficient wet strength.

In the same way, a molded product of the handle part is obtained accordingly. The surfaces of the cup portion and the handle portion to be joined to each other are wetted with water, and immediately afterwards, the surfaces are covered with a trowel using the trowel. Glue the two together. The product so bound is then dried at 110 ° C. for 30 minutes and calcined at 1700 ° C. for 4 hours. Obtain an aluminum-based coffee cup. The bonding strength between the handle portion and the cup portion of the coffee cup is high. It also shows very high impact strength.

Preparation of Acrylic Resin Emulsion F

Stirring blade. 500 parts of water and 4 parts of anionic emulsifier are placed in a five necked flask equipped with a thermometer, reflux condenser, dropping funnel and nitrogen-feeding tube. The internal temperature of the crab is raised to 80 ° C. and 5 parts of potassium persulfate is added. Stir the contents until potassium persulfate is dissolved.

Next, a liquid mixture consisting of 240 parts of methyl methacrylate, 740 parts of ethyl acrylate, 20 parts of hydroxyethyl methacrylate, 1 part of anionic emulsifier and 500 parts of water is added dropwise through a dropping funnel. After complete dropwise addition, the contents were left to stand at 80 DEG C for 3 hours and then cooled. The internal temperature is 30 ° C. or lower, and the pH is adjusted to 9 by adding aqueous ammonia. Water is added to obtain an acrylic resin emulsion having 42% solids.

Comparative Example 1

The cup was obtained in the same manner as in Example 9 except for using slip without addition of the peptizer and the organic binder. The cup is separated from its adhesive area. Therefore, satisfactory plastic products cannot be obtained.

Example 10

The same manufacturing process as in Example 4 was carried out using the same raw materials as in Example 4 to obtain slips having a solid content of 68.9%.

The acrylic resin emulsion G prepared according to the process described below is applied to the slip in an amount corresponding to 3% based on the absolute dry ceramic material. The resulting mixture is stirred to obtain a uniform slip. In the same manner as in Example 9, a cast product is obtained. After these are combined, they are fired. A coffee cup having a high adhesive strength between the handle portion and the cup portion and exhibiting a very high impact strength is obtained.

(Production of Acrylic Resin Emulsion G)

An acrylic resin emulsion G is obtained by carrying out the same steps as the method for producing acrylic resin emulsion F, except that the monomer composition is changed to 500 parts of sterin and 500 parts of 2-ethylhexyl acrylate.

Example 11

A cupper cup was obtained by the same method as Example 10 except for using the synthetic rubber resin emulsion H prepared according to the production method described below as a resin emulsion. The coffee cup has a high adhesive strength between the handle portion and the cup portion and shows a very high impact strength.

Preparation of Synthetic Rubber Resin Emulsion H

1000 parts water, 10 parts sodium dodecylbenzenesulfonate, 7 parts potassium persulfate, 480 parts styrene, 200 parts methyl methacrylate, 300 parts in a polymerization pressure tank made of stainless steel and equipped with a stirring blade and thermometer Butadiene and 20 parts of acrylic acid are added. The contents are stored at 70 ° C. for 12 hours and then cooled. The internal temperature is lowered below 30 DEG C, the pH is adjusted to 9 by addition of aqueous ammonia, and then water is added to obtain a synthetic rubber resin emulsion H having a solid content of 42%.

Example 12

Using the same raw material as described in Example 5, the same manufacturing method as in Example 5 was carried out to obtain a slip having a solid content of 71.4%.

Acrylic resin emulsion F in an amount of 3% based on the absolute dry ceramic material is added to the slip. The resulting mixture is stirred to obtain a uniform slip. In the same manner as in Example 9, a cast product is obtained. These are combined and calcined at l550 ° C. for 3 hours. A coffee cup is obtained which has a high adhesive strength between the handle portion and the cup portion and shows a very large impact strength.

Example 13

Using the same raw material as described in Example 6, the same manufacturing method as in Example 6 was carried out to obtain a slip having a solid content of 65%.

A corresponding amount of acrylic resin emulsion G of 3%, 100 g of phenol resin emulsion (mole ratio of formaldehyde to phenol 2: solids: 50%) based on the absolute dry ceramic material is added to the slip. The resulting mixture is stirred to obtain a uniform slip.

In the same manner as in Example 9, a cast product is obtained. These are combined and calcined at 2150 ° C. for 5 minutes. A coffee cup is obtained which has a very high impact strength with a high adhesive strength between the handle part and the cup part.

Example 14

By carrying out the same production method as in Example 1 using the same raw material as described in Example 1, slip having a solid content of 68.4% is obtained. A copolymer aqueous emulsion (solid content: 43%) containing the monomers shown in Tables 8 (a) to 8 (c) as its structural units is added to each slip. The resulting mixture is stirred to obtain a uniform slip.

Each slip is poured into a plaster mold with a length of 90 mm, a width of 20 mm and a thickness of 5 mm. After standing until a deposit of ceramic particles is formed on the corresponding mold wall, the resulting cast product is demolded from the corresponding mold. In demolding cast products, each cast product is inspected and its demolding is good, and whether the cast product demolded in this way has good moldability (ie, whether it has been cut or deformed). Or not). It is left to stand at room temperature, dried and the strength is measured. In the strength, the flexural strength is measured using "Tensilon UTM-III-500" (trade name, manufactured by Toyo-Bolt Yarn). The cast product thus obtained is calcined to obtain a ceramic product. The ceramic products are very good when each ceramic product is obtained from a cast product obtained from a composition prepared by adding an aqueous emulsion of a copolymer composed of monomers satisfying the proportions specified in the preceding section of the specification, shown in Table 8.

As a method for evaluating the life of each plaster mold, the life of the plaster mold is evaluated according to the following five-step determination method based on the upper limit of the continuous casting operation of the slip for casting the corresponding slip.

100 times or more

Good 70-99 times

69-40 times each

39-20 defects

19 times or less

In each evaluation, the upper limit of the continuous casting operation of the slip was determined by comprehensively considering demolding of the cast product in demolding, shape retention of the cast product after demolding, and roughness of the gypsum mold surface after demolding. At the same time, prosthesis was judged as to whether the cast product contained cuts and deformations that could occur when demolding from the corresponding mold.

The judgment results are summarized in Table 9 (1) -Table 9 (3). In the table, A means an embodiment using an aqueous emulsion of the specific copolymer described above, and B means an embodiment using an aqueous emulsion of a copolymer of a monomer outside the above-described ratio range. In Table 8. The amount of surfactant contained in each aqueous emulsion added to the corresponding slip was based on 100 parts by weight of the total amount of monomer used to obtain the corresponding copolymer. The average particle hardness of each emulsion droplet is also shown.

TABLE 8a

TABLE 8b

TABLE 8c

Table 9a

TABLE 9b

TABLE 9c

In the above examples, prepared using anionic surfactants. By performing emulsion polymerization reaction to the same reaction mixture as a normal reaction mixture used for emulsion polymerization. The aqueous emulsion shown in Table 8 (3) can be prepared. It is a known method to adjust the radius of the droplet of each emulsion. That is, it can carry out by adjusting the density | concentration of a corresponding surfactant at the start of a polymerization reaction.

Example 15

As porcelain for ceramics, "No.22 Topdressing" and "No.30 Topdressing" (trade name: all manufactured by Marui Coating Co., Ltd.) and "New Ubon 57 No." Product), and then add water glass 1 in an amount of 0.26% based on the dry solid content of sojito, and then add more water. Each resulting mixture is stirred to produce a slip containing 69.1% solids. To each slip is added an aqueous emulsion (solid content: 43%) with the composition shown in Table 8 (1) (5) of Example 14 by an amount corresponding to 3% based on the absolute dry solids of sogitto. The method of Example 14 is carried out to obtain a cast product. It evaluated in the same manner as in Example 14, and the results are shown in Table 10.

TABLE 10

Example 16

A slip having 81.4% solids was obtained by carrying out the same production method as in Example 3 using the same raw material as in Example 3. An aqueous emulsion (solid content: 43%) of each composition shown in (1) to (43) of Example 14 was added to each slip in an amount equivalent to 3% based on the absolute dry aluminum powder mixture. The slip is slip cast in the same manner as in Example 14. After drying at 110 ° C., the dry flexural strength was measured and evaluated in the same manner as in Example 14 except that it was expressed as dry flexural strength. The results are shown in Tables 11 (a) to 11 (c). Table A shows the Example using the aqueous emulsion of the special copolymer mentioned above, B shows the Example using the aqueous emulsion of the copolymer which does not keep the fraction of the monomer mentioned above.

TABLE 11a

Table 11b

TABLE 11c

Example 17

Silica (silica silicate from China), Zirconier ("Tz-3Y", trade name; manufactured by Toyo Soda Co., Ltd.), and β-type silicon carbide ("Betarundum Ultrafine", trade name; manufactured by Ibiden Co., Ltd.) Using to produce a slip for use in slip casting according to the method described below. To each slip is added an aqueous emulsion (solid content: 43%) of the composition given in Example 14 (5) in an amount corresponding to 3% based on the dry ceramic somato. In the same manner as in Example 16, the slip thus produced was slip casted. Table 12 shows the results of the evaluation conducted in the same manner as in Example 16.

Manufacturing method of slip casting slip:

(a) Silica (silicone made in China): The amount of peptizing agent ("Seruna D-305", trade name; Zhuo Yushi Co.) ) Add water. The resulting mixture is stirred to give a slip with 68.9% cross.

(b) Zirconia: 10 kg of zirconia ("Tz-3Y", trade name; manufactured by Toureda Co., Ltd.), 200 g of peptizing agent ("Ceruma D-305", trade name; produced by Chuko Ohshi Co., Ltd.) and water Add. The resulting mixture is stirred to obtain a slip containing 71.4% solids.

(C) β-type silicon carbide

1000g β-type silicon carbide ("Betarundum Ultrafine", trade name; manufactured by Ibiden Co., Ltd.), 3g of boron (manufactured by Mitsuwa Chemical Co., Ltd.), 5g of peptizing agent ("SN Dispersant 5045", trade name, Sunnokko) Co., Ltd. product, 10 g of 10% monoethylamine aqueous solution (manufactured by Kishiga Chemical Co., Ltd.), and water are added. The resulting mixture is stirred to produce a slip having 65% solids.

TABLE 12

As shown in Examples 14-17, slip casting may be performed on a slip composition to which an aqueous emulsion of a special copolymer is applied to obtain a cast product having improved dry strength. Furthermore, when demoulding the cast product from its corresponding mold, excellent demolding and prosthesis are exhibited. Thus, the yield of the cast product can be increased to a considerable level, and also the life of each gypsum mold can be extended. Therefore, when producing using slip casting according to the casting process of the present invention, it is possible to produce an excellent cast product having a high efficiency.

Claims (1)

a) making a slip composition by mixing a slip containing a ceramic sojito as a main component and a resin emulsion; b) forming two or more cast articles with a slip composition according to the slip casting method, wherein the cast articles have the same or different appearance and are in a bonding relationship such that the mold moldings each have at least one set of joint surfaces to be joined; c) applying a bonding medium containing ceramic clay and a resin emulsion as the main component to at least one bonding surface of the cast product; d) joining the joining surfaces of the cast products to join the cast products to form an integrated cast product; And e) firing the integrated cast product.