JPH0354157A - Inorganic powdering oxide superconductor for body and burned material obtained by burning same composition - Google Patents

Abstract

PURPOSE:To provide high plastic forming properties to an inorganic powder in water system and simultaneously obtain a burned article having excellent strength and dimensional accuracy by blending substantially non-plastic inorganic powder with Paramilon. CONSTITUTION:The inorganic powder composition for body obtained by blending substantially non-plastic inorganic powder with paramilon. When other forming assistant is used together with paramilon, higher plastic forming properties can be preferably provided to the substantially non-plastic inorganic powder. As the such forming assistant, e.g. cellulose based compound, polyhydric hydroxy compound, polyvinyl polymer, etc., is preferably used. The paramilon is blended ordinarily at an amount of about 0.1-10pts.wt. based on 100pts.wt. inorganic powder. As the substantially non-plastic inorganic powder, fine ceramic powder, kaolinite, natural kaolin, talc and cebiolite, etc., is exemplified, but more effective when fine ceramic powder is used.

Description

[Detailed Description of the Invention] The present invention relates to an inorganic powder kneaded material and a burnable material obtained by burning the same. The present invention relates to an inorganic powder kneaded composition made by imparting plasticity to inorganic powder in an aqueous system, and an inorganic powder kneaded product obtained by baking such a composition.

Traditionally, a typical method for plastic shaping of inorganic powder was known as molding clay-based clay consisting of clay and water on a potter's wheel. Extrusion molding using molds has also come into practical use. Clay-based clay inherently has plasticity and can be easily shaped by plastic molding as described above.

However, in recent years, fine ceramic powders such as alumina and zirconia have come to be used as new materials in various fields, but these inorganic powders called fine ceramic powders are It does not have sufficient plasticity to be plastically molded, and therefore, as it is,
For example, it cannot be extruded.

In general, in order for an inorganic powder to be shaped into a plastic shape, for example, by extrusion, the inorganic powder has plasticity in the narrow sense of being able to be deformed and molded into a predetermined shape by stress, and the clay is removed from the die during shaping. Smoothness for smooth extrusion, shape retention for the extruded rod to maintain its shape during the process of drying, and shape retention for the obtained rod to be burned after drying. The fabric is required to have the strength to withstand the processing and other handling that occurs during the process. These are collectively referred to as plasticity in a broad sense, and the above-mentioned clay-monohydrous clay inherently has such plasticity. However, the fine ceramic powder mentioned above is
It does not substantially have such plasticity and is called a non-plastic clay, and therefore cannot be plastically shaped as it is.

For this reason, in order to impart plastic moldability to such fine ceramic powders, for example, "Ceramics" Vol. 22, No. 5, pp. 385-392 (198
7], various organic substances are added as peptizers, binders, lubricants, plasticizers, etc. For example, typically, the deflocculant is a polymer electrolyte such as an acrylic acid homopolymer, a copolymer thereof, or a salt thereof, and the binder is a water-soluble polymer such as polyvinyl alcohol. As lubricants, emulsions of wax and stearic acid are known, and as plasticizers, glycerin, polyethylene glycol, etc. are known for water-based clays, and phthalate esters are known for oil-based clays.

In the extrusion molding of fine ceramics, these organic substances are usually added in an amount of about 5 to 20% by weight based on the fine ceramic powder.

Furthermore, in products such as electronic parts and mechanical parts, which are important application fields for molded and fired products of fine ceramic powder, strict dimensional accuracy is required for large-sized objects, so injection molding is often used. will be honored at. This injection molding is made of fine ceramic powder, binders of thermoplastic resins such as polystyrene, polyethylene, polypropylene, cellulose acetate, acrylic resins, ethylene-vinyl acetate copolymers, plasticizers such as phthalate esters, and stearin. Add 10 to 30% by weight of organic substances such as lubricants such as acids, heat and knead,
This method involves preparing a non-aqueous clay composition and injecting it into a mold in the same manner as injection molding of a thermoplastic resin.

As described above, it is possible to impart plastic moldability to fine ceramic powder to some extent using conventional methods.・In order to mix it into ceramic powder, during firing after molding, the temperature is raised at a very slow rate to about 500°C, at which point these organic substances decompose, thereby completely eliminating the so-called degreasing. Productivity is extremely low as it requires a lot of work. Furthermore, since the precept form containing a large amount of organic material exhibits a large volumetric shrinkage upon burning, it is not easy to manufacture products that require dimensional accuracy.

Furthermore, in conventional plastic molding of fine ceramics, it has been necessary to mix as many as 5 to 10 types of organic substances depending on the role. It is necessary to prepare a composition, and it is not easy to design the composition of the dressing composition.

Conventionally, even though it has been possible to impart a certain degree of plasticity to fine ceramics, it is difficult to say that it is sufficient; It is necessary to select many kinds of organic substances and to mix them in large amounts according to the use and required physical properties, which makes it difficult to formulate or design the composition for clay. In this case, a degreasing process is required, and thus, as mentioned above, productivity is low, and cracks and dimensional changes occur during burning, which ultimately increases the product price.

The present inventors solve the above-mentioned problems in the plasticization of inorganic powders, such as the fine ceramic powders, which have substantially no plasticity, and in the burning of compositions so plasticized. As a result of intensive research, we found that by adding a small amount of paramylon to fine ceramic powder, it was possible to impart high plastic formability to a substantially non-plastic inorganic powder in an aqueous system. The present invention was developed based on the discovery that by firing a product, a fired product with excellent strength and dimensional accuracy can be easily obtained.

That is, the present invention provides an inorganic powder having substantially no plasticity,
In particular, an inorganic powder kneaded material made of the above-mentioned fine ceramic powder that has plastic moldability in an aqueous system, and an inorganic powder fired product made by baking such a composition. The purpose is to provide

13L Ikkei for "?" The present invention is characterized in that the Mi powder for clay is made of a substantially non-plastic inorganic powder containing paramylon.

Furthermore, the inorganic powder incineration material according to the present invention is characterized in that it is obtained by incineration of such a clay composition.

In the present invention, the substantially non-plastic inorganic powder is an inorganic powder that does not substantially have plasticity in the broad sense described above, and specific examples include alumina, zirconia, titania, and silica. , oxide-based inorganic powders such as magnesia, ferrite, barium titanate, and cordierite, carbide-based inorganic powders such as silicon carbide, boron carbide, and tungsten carbide, and nitrides such as silicon nitride, aluminum nitride, and boron nitride. Examples include physical inorganic powders, boride-based inorganic powders such as zirconium boride and titanium boride, and calcium phosphate compounds such as kaolinite, natural kaolin, talc, sepiolite, hekai clay, and hydroxyabartite. . The present invention is particularly suitable for producing clay compositions made of fine ceramic powders among the above-mentioned inorganic powders, and baked products thereof. Furthermore, in the present invention, the inorganic powder may be used alone or in combination with two
It is used as a mixture of more than one species. However, in the present invention, it is desirable that these inorganic powders in the clay composition have a particle size as small as possible, particularly 1 μm.
It is preferred to have a particle size of:

Paramylon used in the present invention is a polysaccharide mainly composed of β-1,3 glucosidic bonds, and is a type of storage polysaccharide that is accumulated in the cells of the microorganism Euglena. Such paramylons are, for example, Ca
rbohydrate Research+ 25+
231242 (1979) and Japanese Unexamined Patent Application Publication No. 1,37297.

Paramylon is a polysaccharide produced by microorganisms, and in the present invention, it may be used unpurified or highly purified. In addition, para-ξron powder usually does not have heat-coagulability, but in order to make it heat-coagulate, it may be treated with alkali if necessary.

In the present invention, the blending amount of paramylon is 10% of the inorganic powder.
It is usually in the range of 0.1 to 10 parts by weight, preferably in the range of 0.5 to 5 parts by weight.

In the present invention, by using paramylon together with other molding aids, even higher plastic moldability can be imparted to the virtually non-plastic inorganic powder. In addition, by molding the obtained clay composition using a conventional molding method and burning it, it is possible to obtain a baked article with even greater strength. As such a molding aid, for example, a cellulose compound, a polyhydric hydroxy compound, or a polyvinyl polymer is preferably used.

Examples of the above-mentioned cellulose compounds include cellulose derivatives such as methylcellulose, ethylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, and hydroxybutylated cellulose. Examples of polyvalent hydroxy compounds include alkylene glycols such as glycerin, ethylene glycol, propylene glycol, triethylene glycol, and 1,3-butylene glycol, and polyoxyalkylene glycols such as polyethylene glycol and polypropylene glycol. . Examples of polyvinyl polymers include polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid resins, polyacrylates, such as ammonium polyacrylate, acrylic acid-maleic acid 62 copolymer, and ammonium salts thereof. be able to. The polyacrylic acid resin may be crosslinked. Such cross-linked polyacrylic acid resins are already known and can be produced manually as commercially available products.

In addition to the above, various other formulation auxiliaries can be used, for example, carboxyl methyl starch can also be used as an auxiliary agent.

In the present invention, these adjuvants may be used alone, but they can also be used as a mixture of two or more. The molding aid is usually used in an amount of about 0.1 to 10 parts by weight, preferably about 0.1 to 10 parts by weight (when a mixture of two or more is used, as the total amount) per 100 parts by weight of the inorganic powder. 5～
It is blended in an amount of 5 parts by weight.

Furthermore, in the present invention, a surfactant known as a wetting agent such as an alkyl ether of polyethylene glycol, or a lubricant such as zinc stearate, aluminum stearate, or magnesium stearate may be used. It may also be included in the soil composition.

In the present invention, the method for preparing the composition for inorganic powder clay is not particularly limited. For example, paramylon and other forming aids as needed are added to the fine ceramics powder in powder form, or paramylon and other forming aids are added as needed to the fine ceramics powder in advance with water, Alternatively, dissolve it in a small amount of a water-soluble organic solvent such as methanol, ethanol, etc., add this to the fine ceramic powder, and then mix thoroughly to prevent paramylon and other molding aids from being unevenly distributed. The composition for clay according to the present invention, which is suitable for plastic molding, can be obtained by preparing a mixture, then adding an appropriate amount of water to the obtained mixture, and thoroughly kneading the mixture. However, paramylon and other molding aids may be mixed separately into the powder.

Furthermore, the inorganic powder kneaded composition prepared as described above may be subjected to injection molding, extrusion molding, roll extrusion, roll rolling, etc.
The inorganic powder fired product of the present invention, which has excellent strength and dimensional accuracy, can be obtained with high productivity by molding it into a desired shape according to a conventional method, drying it, and then firing it. The firing temperature is appropriately selected depending on the inorganic powder used.

The composition for inorganic powder clay according to the present invention is a water-based plastic moldable composition made of a substantially non-plastic inorganic powder containing a small amount of paramylon, and is an excellent material. It has plastic formability and can be formed into any shape by normal means.

Furthermore, according to the present invention, the inorganic powder kneaded composition is molded into a desired shape by, for example, extrusion or injection molding,
By drying and baking, an inorganic powder sintered product with excellent strength and dimensional accuracy can be obtained with high productivity.

The present invention will be explained below with reference to Examples and Reference Examples.
The present invention is not limited in any way by these Examples.

Reference example (alkali treatment of paramylon) 2g of paramylon powder was added to 20% of IN aqueous sodium hydroxide solution.
0m. After dissolving in I under stirring, 4N hydrochloric acid was added thereto to adjust the pH to 6.0 to neutralize and precipitate β-1,3-glucan. The resulting neutralized solution was transferred to a Tommy centrifuge (
The mixture was concentrated at 8,000 rpm for 10 minutes, and 200 ml of water was added to form a slurry again.

This slurry was concentrated by centrifugation in the same manner as above,
50 g of paste was obtained. Freeze this at -20''C, add twice the amount of ethanol, freeze, and use filter paper to
Suction filtration under vacuum yielded 8 g of dehydrate. This dehydrated product was vacuum dried at 60° C. to obtain about 2 g of porous powder.

When the gel strength of the β-1,3-glucan powder obtained as described above was measured using the method described below, it was 200 g/cffl at a 2% concentration, and it had gel-forming ability. Paramylon, the raw material, was not found to have any gel form.

Add 10 ml of water to the above-mentioned concentration of Kotori Kepi β-1,3-glucan, homogenize it with a bottle homogenizer, vacuum degas it, put it in a test tube (diameter 1.6 cm), and place it in a boiling water bath. and heated for 10 minutes. Next, after cooling in tap water for 30 minutes and cutting into low height pieces, the gel strength was measured using a card meter (Iio type). Hereinafter, the powder of Balamilon used as the raw material will be referred to as Baratanron A, and its alkali-treated product will be referred to as Haramilon B.

Next, the plasticity of clay kneaded soil is defined by the strength and number of hydrogen bonds caused by the interaction between the clay mineral surface and water, that is, the bound water, and the plasticity characteristic value CV defined by the following equation is the plasticity It is said that it can be used as a scale to express the degree of
Page (1984)).

However, here, W4. and WI0. is the plastic deformation ratio H. when plasticity is measured using the Petzferkorn test method. Drying temperature of 40℃ and 1
The weight of the sample at 00° C. is shown, and wit is the weight of the sample at room temperature.

Therefore, in the following examples, plasticity was evaluated by measuring the plasticity properties of clay compositions prepared from various inorganic powders using a simple method similar to the above test method.

That is, the predetermined amount of the prepared clay U (W R t )
was accurately weighed and first dried at 40°C for 3 to 4 days to obtain a constant weight.The sample weight (W4.) was measured.Then, this sample was heated and dried at 100°C for 1 day or more to obtain a constant weight. The sample weight! (W+...) was measured, and the plasticity characteristic value Cv was calculated from these measured values based on the following formula.

Example 1 As shown in Table 1, easily sinterable low soda alumina (AES-11 manufactured by Sumitomo Chemical Co., Ltd., BET specific surface area 6 to 7 m/
A predetermined amount of Baragoron A or B was added to 50 g (average particle size: 0.4 to 0.5, crm) and thoroughly mixed to obtain a homogeneous mixture.

Next, 20 g of distilled water was added to this mixture, and after kneading it uniformly, it was sealed in a resin bag and placed in a constant temperature bath at 40°C, and left to ripen all day and night. , kneaded while sealed in the bag, aged again for a day and night, and used as a test clay according to the above.
Plastic property values were measured. The results are shown in Table 1.

For comparison in Table 1, a clay composition was prepared using polyethylene glycol instead of paramylon, and the plasticity properties were measured when the alumina was used alone.

The results are shown in Table I.

As is clear from the results shown in Table 1, according to the present invention, a clay composition having high plasticity in an aqueous system can be obtained by blending a small amount of Baradanron A or B with alumina. .

Example 2 As shown in Table 2, New Zealand Kaolin 50
A predetermined amount of paramylon B was added to g and thoroughly mixed to obtain a homogeneous mixture, and this mixture was then treated in the same manner as in Example 1 to obtain a test clay. Plasticity characteristic value CV was determined using the same method.

For comparison, the plastic property values when using the New Zealand kaolin alone were measured in the same manner as above,
The results are shown in Table 2. New Zealand kaolin is
Although the material itself has some plasticity, according to the present invention, even higher plasticity can be imparted.

Table 2 Example 3 After adding paramylon A or B and a formative aid to the various inorganic powders shown in Table 3 and thoroughly mixing them, using a 0.51 volume Niwa Niichi Gu, While mixing, an appropriate amount of water was added to the mixture and kneaded for 30 minutes to prepare a kandogumi kaimono. Methyl cellulose as a molding aid is a 2% aqueous solution with a viscosity of 400 cp at 20°C, and polyethylene glycol has an average molecular weight of 160 cp.
0 0 was used.

A certain amount of the obtained kadogumi ritual was loaded into a flow tester (CFT-500 manufactured by Shimadzu Corporation), and the extrusion load was 10~
The material was extruded into a string-like material having a diameter of 1 U in a range of 300 kgf, and extrusion moldability was examined. Extrusion moldability is considered excellent when a string-like object with a length of 1 m or more can be obtained without breaking during extrusion, and when a string-like object with a length of about 1 m can be obtained. The condition was judged as good, and the case where the bottom-shaped object broke before being given a string-like object with a length of 1 m was judged as poor formability.

The results are shown in Table 3.

Example 4 A predetermined amount of Paraξlon B is added to the AlξNa AES-11 powder.
and, if necessary, a forming aid, and after thorough mixing, a predetermined amount of water was added and kneaded for 30 minutes under reduced pressure to prepare an alumina plating composition.

This clay composition was extruded with a flow tester at a load of 200k.
It was extruded into a rod-shaped product with a diameter of 51 mm and a length of 50 m using gf. This was dried at room temperature for 24 hours, at 40°C for 24 hours, and then at 115°C for 24 hours.

Next, this dry molded product was loaded into an electric furnace and heated from room temperature to 8.
Heat at a rate of 3°C/min to 00°C, hold at 800°C for 3 hours, then heat at 2"C from 800°C to 1600°C.
The mixture was heated at a rate of 1/min, then held at 800°C for 3 hours, and then allowed to cool in the furnace.

The alumina calcined product thus obtained was tested using a Shimadzu autograph (AG-IQQO type).
Span length 20㎜1, crosshead a degree 0. 5/
The three-point bending strength was measured at 30 minutes. The results are shown in Table 4.

The three-point bending strength σ (kgf/mm") is determined by the following formula.

σ=8PL/πd3 Here, P is the maximum load at failure (kgf), L is the distance between fulcrums (am), and d is the diameter of the test piece.

For comparison, 400g of the alumina AES'-11
5 parts by weight of a commercially available binder was added to the mixture, an alumina calcined product was prepared in the same manner as above, and the three-point bending strength was measured.

As shown in Table 4, the baked product obtained by firing the clay composition according to the present invention can obtain greater three-point bending strength with less than half the amount of commercially available binder.

Claims (6)

[Claims] (1) An inorganic powder clay composition comprising paramylon contained in a substantially non-plastic inorganic powder. (2) The composition for an inorganic powder clay according to claim 1, wherein the inorganic powder is a fine ceramic powder. (3) The composition for inorganic powder kneaded clay according to claim 1, which contains other molding aids together with paramylon. (4) An inorganic powder fired product, which is obtained by firing an inorganic powder clay composition comprising paramylon contained in a substantially non-plastic inorganic powder. (5) The fired inorganic powder product according to claim 4, wherein the inorganic powder is fine ceramic powder. (6) The fired inorganic powder product according to claim 4, which contains other molding aids together with paramylon.