JPS61112602A - Mold for molding ceramics - 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] [Field of Application of the Invention] The present invention relates to a mold for molding a ceramic molded product by injecting a slurry consisting of fine refractory particles and water, and particularly to a mold for molding ceramics suitable for a core. .

[Background of the invention]

Conventionally, in the so-called slip casting method, in which ceramic materials are formed by injecting slurry into a mold, water in the injected slurry is absorbed using a water-absorbing mold (for example, a plaster mold described in JP-A-57-176107). It is used to absorb and rapidly solidify. However, these molds (cores) have a high strength and are difficult to deform, so they have the disadvantage that they prevent shrinkage when the slurry dehydrates and solidifies, causing cracks in the ceramic material.

[Purpose of the invention]

An object of the present invention is to provide a ceramic mold that can provide sufficient shrinkability to the mold and prevent cracking of solidified ceramics.

[Summary of the invention]

The feature of the present invention is that the mold is made of soft foam plastic, which is impregnated with an aqueous solution of a water-soluble substance, and then cooled or dried to solidify or precipitate the water-soluble substance and harden the mold. By doing so, the desired shape of the mold is maintained.

A mold hardened by solidification or precipitation of a water-soluble substance has a smooth surface because the pores on the surface of the foam plastic are filled with the water-soluble substance. The surface of the ceramic mold becomes smooth. Furthermore, the mold becomes deformable when it absorbs water in the slurry and dissolves the water-soluble compound. Therefore, there is no resistance to shrinkage during solidification of the ceramic slurry, and cracking of the ceramic molded product can be prevented.

The mold that has absorbed water in this way is easily deformed and can be removed from the ceramic molded article, and the mold can be reused by impregnating a water-soluble substance with an aqueous solution and hardening it by cooling or drying.

[Embodiments of the invention]

Examples of the present invention will be described in detail below.

[Mold the core of the pump casing using 1 part polyurethane foam (soft), add 35 parts of sodium chloride, 100 parts of water
The core was impregnated with an aqueous solution consisting of 100% chloride, dried at 110°C, and sodium chloride was precipitated into the pores to harden the core.Then, a ceramic slurry was poured into the core using the core and a plaster mold. When the pump casing was molded, the core part softened due to moisture absorption and deformed as the ceramic solidified and shrunk, resulting in a ceramic molded product without any cracks.

[Mold the core of the combustion chamber of the gas combustor using two-part foamed polyvinyl alcohol, add 100 parts of potassium carbonate, and 90 parts of water.
The core was impregnated with an aqueous solution consisting of 50% and dried at 180°C to precipitate potassium carbonate into the pores and harden the core.6 Next, ceramic slurry was injected into the core using a plaster mold. Then, a ceramic molded product was formed. At this time, the core softened due to moisture absorption and deformed as the ceramic molded product solidified and shrunk, resulting in a crack-free ceramic molded product.

[A core for a pump casing was molded using three-part foamed polyamide resin (nylon), and 100 parts of potassium carbonate,
The core was impregnated with an aqueous solution consisting of 90 parts of water, dried at 200°C, and potassium carbonate was precipitated into the pores to harden the core.Then, a ceramic slurry was made using this core and a plaster outer mold. It was injected and a ceramic molded article was formed. At this time, the core softened due to moisture absorption and deformed as the ceramic solidified and shrunk, resulting in a crack-free ceramic molded product.

[A combustion chamber core made of 4-part foamed polypropylene was impregnated with a mixture of 50 parts of calcium chloride and 50 parts of water as an aqueous solution by heating to 40°C, and solidified by cooling to room temperature to harden the core. Ta. A ceramic slurry was injected into the core and a plaster outer mold to form a ceramic molded product. At this time, the core softened due to moisture absorption and deformed as the ceramic solidified and shrunk, resulting in a ceramic molded product without any cracks.

[5] Polyvinyl Al Sky-JL/ (PVA-1!
7) 20 parts, water 80 parts, starch 5 parts, formalin 12 parts
1 part of sulfuric acid was added thereto, thoroughly stirred, poured into a mold for molding, held at 50°C for 10 hours, taken out from the mold and washed with water to mold a foam for a pump casing core. Next, this foam was impregnated with an aqueous solution consisting of 100 parts of potassium carbonate and 80 parts of water and dried at 180° C. to harden the core by precipitation of potassium carbonate.

Ceramic slurry is made using this core and a plaster outer mold.
When injected, the core softened due to moisture absorption and deformed as the ceramic solidified and shrunk, resulting in a crack-free ceramic molded product.

As shown in this example, foam plastic of any shape can be molded and used as a core, and the porosity and
It is possible to change the hardness etc. arbitrarily, and by impregnating this with an aqueous solution of any water-soluble compound and precipitating a solid, it can be deformed in a dry or low temperature state to obtain a violet core.

[6] A foam plastic core was taken out from the ceramic molded product manufactured using the core produced in Example 5, washed with water, placed in a mold for shaping, and then mixed with 100 parts of potassium carbonate and 8 oz of water. The molded product was impregnated with a solution of 1.3%, dried and hardened, placed in an outer mold, and injected with ceramic slurry to obtain a crack-free molded product.

In this way, the foam plastic core can be used repeatedly 7 times, and because it has high tensile strength and bending strength in the hardened state, there is no damage to the core.

Since it does not deform in the hardened state, a ceramic molded product with an accurate shape can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, a water-soluble compound is precipitated in the pores of a soft foam plastic that is easily deformed when used as a mold, and is used as a mold. When the compound is dissolved, it is easily deformed and does not prevent the ceramic from shrinking during solidification, so it does not cause cracks in the ceramic. Again 1
The foamed plastic cured according to the invention has a high tensile strength.

It has high bending strength and can be reinforced by inserting metal wires, etc., so it is possible to manufacture 4-wall molds or large molds, and the surface of counterfeit ceramics will be smooth, making it practical. target and C

Claims (1)

[Scope of Claims] 1. For ceramic molding, characterized in that a soft foam plastic molding containing bubbles or pores is impregnated with a solution of a water-soluble compound and hardened by drying, cooling, etc. template. 2. The mold according to claim 1, wherein the foam plastic is polyurethane, polyethylene, vinyl chloride, polyamide, polypropylene, polyvinyl alcohol, or a derivative thereof. 3. In the mold according to claim 1, the water-soluble compound impregnated into the foam plastic is sodium chloride, potassium chloride, calcium chloride, sodium carbonate, potassium carbonate, trisodium phosphate, disodium hydrogen phosphate, sulfuric acid. A ceramic forming mold characterized by being made of either magnesium.