JPS616172A - Ceramic composition for injection molding - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a ceramic composition suitable for injection molding.

(b) Conventional technology It is generally well known that ceramic products are manufactured by blending an organic binder with ceramic raw materials to give them fluidity, obtaining a green molded body by injection molding, and then baking the green molded body with BS2 resin. ing.

Compared to other methods such as hollow press, rubber press, and paid molding, the injection molding method can produce products with complex shapes in large quantities, and hardly requires finishing machining.

(c) Problems to be Solved by the Invention In order to produce defect-free ceramic products using the injection molding method, the properties of the organic binder used, especially the fluidity, mold releasability, and binder removal properties, are important. However, in the injection molding process, if the selection or combination of binders is not good, Tadai's @Akebono binder is used to provide fluidity. As a result, the strength of the green molded product decreases, and cracks are likely to occur at the boundary between the thick part and the thin part of the mold opening 11,). Furthermore, depending on the selection of the organic binder, not only defects such as sink marks, weld lines, distortions, and cracks may occur in the green molded product, but also defects such as blisters, cracks, and surface layer peeling may occur in the degreased culm. The reality is that it is difficult to obtain conventional compositions that undergo injection molding without such defects.

The present invention has been made in order to eliminate the drawbacks found in the conventional compositions described above, and aims to provide a ceramic composition suitable for injection molding that is free from the above-mentioned defects. .

(d) Means for solving the problem The structure of the present invention for solving this problem consists of a ceramic powder serving as a base material of the composition, and a thermoplastic resin as an organic binder serving as a carrier for this powder. , a lubricant and a plasticizer are used, a polyamide resin is used as the thermoplastic resin, and the blend ω of this organic binder is 10 to 3 of the composition.
The gist is that the amount of 0W is %.

Ceramic powders include alumina, zirconia,
Silicon nitride, silicon carbide, etc. can be used. Examples of polyamide resins include nylon 6, nylon 66, nylon 10, nylon 11, vylon 12, and nylon 6.
10M, but those with a molecular ff of about 11,000 to 100,000 are preferable for use as a component of a ceramic composition. The lubricant and plasticizer are those that volatilize at a lower temperature than the polyamide resin used, and as a lubricant, 4-aralic acid is used,
As a plasticizer, for example, diactyl phthalate is used.

From the point of view of moldability, does it mean that the blending ratio of the organic binder to the entire composition is less than 10% by weight? IIy-, which makes it difficult to completely fill the green molded body and causes defects such as sink marks, weld lines, distortions, and cracks. Furthermore, if the blending ratio exceeds 300 layers, defects such as cracks and surface layer peeling may occur in the molded product after degreasing, and the density of the molded product decreases due to blistering, which causes a lack of strength.

When the blending ratio of polyamide resin is less than 9% for 5,
R1') of the ceramic and organic binder becomes difficult, and defects such as distortion and cracks occur in the green molded body. In addition, if the blending ratio exceeds 255, the time required to remove the organic binder becomes long, and the density of the compact after removing the organic binder becomes small, making it difficult to obtain a high-density sintered ceramic product. .

(e) After the active composition is kneaded, it is pulverized and injection molded to form a so-called green molded product, which is heated and degreased and further fired to obtain a sintered Hiramix product.

EXAMPLE The following is a detailed explanation of the present invention. 86% by weight of alumina powder was used as the lamic powder, and the following organic binder was used. In addition, 10% by weight of nylon 12 was used as the polyamide resin, 122 weight% of stearic acid was used as the lubricant, and 2% by weight of dioctyl phthalate was used as the replasticizer.

These compositions were kneaded at 150° C. to form a homogeneous mixture, which was then pulverized to obtain a composition for injection molding. Next, when molded into a mold using a screw-in-line type extrusion molding machine, no defects such as cracks, weld lines, cracks, or distortions were found in this green molded product. The compact was degreased by gradual heating to IF7.No defects such as blistering, distortion, cracks, or surface peeling were observed in this degreased compact.Subsequently, this compact was heated to 1550°C. After firing at ℃, a good sintered ceramic product was obtained.

(G) Effects of the Invention As mentioned above, according to the composition of the present invention, the green molded product has almost no defects such as sink marks, weld lines, distortions, and cracks, and there are no blisters, cracks, or surface peeling during the degreasing process. This has the effect that a sintered body with good properties can be obtained with almost no defects such as.

Patent applicant: Kuchiki Kogyo Co., Ltd. Representative name: Mankichi Tateno (Voluntary author of the procedural amendment) July 20, 1980

Claims (1)

[Claims] 1. Using a thermoplastic resin, a lubricant, and a plastic material as a ceramic powder and an organic binder serving as a carrier for the ceramic powder, and using a polyamide resin as the thermoplastic resin, A ceramic composition for injection molding, characterized in that the amount of the organic binder is 10 to 30% by weight of the composition. 2. The ceramic composition for injection molding according to claim 1, wherein the amount of polyamide resin is 5 to 25% by weight of the composition.