JPS6049565B2 - Manufacturing method for inorganic molded products - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing an inorganic molded article.

BACKGROUND ART Conventionally, molding materials of various shapes have been formed by placing molding materials containing water and hydraulic inorganic substances such as cement, gypsum, and calcium silicate forming materials into molds. Molded articles made of these molding materials harden in the presence of an appropriate amount of moisture, but the presence of excess moisture impedes hardening, so excess moisture is removed from the molded articles. For this reason, a mold with many small holes is used, and dehydration is carried out by reducing pressure from the outside of the mold, but the molding material is not well distributed in the parts of the molded product. This causes localized dehydration passages and prevents uniform dehydration over the entire molded product, and the dehydration passages expand as dehydration progresses, causing a reduction in the strength of the molded product. The present invention solves the drawbacks of the above-mentioned conventional methods for producing inorganic molded products, and allows dehydration from the molded product to be uniformly performed over the entire molded product, without creating local dehydration passages in the molded product. It is an object of the present invention to provide a method for manufacturing an inorganic molded article that can quickly cure the molded article without any problems.

The gist of the present invention is to mold a molding material containing a hydraulic inorganic substance and water into a mold having a large number of small holes, and then to mold a stretchable sheet over the molding material. The method is characterized in that the sheet is brought into close contact with the surface of the molded product by applying reduced pressure from the outside of the mold, thereby dehydrating the molded product.

~It consists in a method for manufacturing an inorganic molded article. Next, the method for manufacturing the inorganic molded article of the present invention will be explained in more detail.

The hydraulic inorganic material that is a component of the molding material in the present invention is an inorganic material that hardens through a hydration reaction, such as cement, gypsum, and calcium silicate forming materials.

The molding material may contain inorganic fibers such as mineral fibers and glass fibers, organic fibers such as animal fibers, vegetable fibers, synthetic fibers, and semi-synthetic fibers, as well as aggregates such as sand and gravel. , a quick hardening agent, a pigment, etc. A mold 2 for molding a molded article 1 has, for example, a bottom wall and a peripheral wall, and a large number of small holes 3 are provided in a substantially uniform distribution over the entire mold surface.

The diameter of the small holes 3 is preferably large enough to hardly cause clogging with the molding material and to allow air and water to pass through, for example, a diameter of 1 to 5 Tf0n. . The total area of the small holes 3 in the entire surface area of the mold is made to account for, for example, 5 to 30% in order to improve the dehydration of the molded product 1 by reducing the pressure from the outside of the mold 2. To mold the molded article 1, for example, a spray molding method is used in which molding material is sprayed onto the mold surface to a constant thickness of S, or molding is performed in the gap between the mold 2 and the mold to be closed. A casting method, in which material is injected and molded, is suitable. However, the molded product 1 contains a large amount of water,
When a hydraulic reaction is caused in the molded article 1, if it is left as is, excess moisture remains and hardening is not done quickly.

In addition, when dehydrating the molded product 1 by reducing pressure through the large number of small holes 3 in the mold 2, local dehydration passages are created in places where the molding material distribution of the molded product 1 is relatively rough. ,
A uniform dehydration effect cannot be obtained from the entire molded product 1, and dehydration is difficult. The channels tend to expand as dehydration progresses, causing a decrease in the strength of the molded product 1. Therefore, in the present invention, a stretchable sheet 4 is placed over the molding material,
The pressure is reduced from the outside of the mold 2.

Sea with elasticity!卜4 is a sheet that has the property of being able to legally elongate and expand its area due to external force, such as rubber such as butyl rubber, urethane rubber, butadiene rubber, natural rubber, soft polyethylene resin, soft vinyl chloride resin, etc. 4. It is preferred to be formed from a soft synthetic resin. The degree of elongation is determined appropriately depending on the depth of the mold 2, etc., but it should be at least a degree that allows the sheet 4 to be brought into close contact with the surface of the molded product 1. It is preferable that the peripheral edge of the sheet 4 is fixed to the peripheral edge on the mold, and for this purpose, a fixing frame 5 is used and the peripheral edge of the sheet 4 can be pressed down with a fastener 9. The sheet 4 may be installed with the middle portion hanging downwards as in FIG. 1, and this is preferred if the degree of stretching is relatively small. In order to reduce the pressure from the outside of the mold 2, it is preferable to provide a vacuum box 6 on the outside of the mold 2. 7 is a suction passage, and 8 is a vacuum pump.

By applying reduced pressure from the outside of the mold 2, the sheet 4 is stretched and brought into close contact with the surface of the molded product 1. At this time, a pressing force can also be applied to the sheet 4 from the outside. Dehydration from the molded product 1 is achieved by reducing the pressure from the outside of the mold 2. When the pressure is reduced, the sheet 4 quickly adheres to the surface of the molded product 1, and the sheet 4 is dehydrated from the molded product 1. Dewatering is performed with the sheet 4 in close contact with the surface of the molded product 1.

When dehydration occurs with the sheet 4 in close contact with the surface of the molded product 1, a nearly uniform suction force acts over the entire molded product 1, and the molded product 1 is removed from the entire surface. The water shall be dehydrated in a similar manner without creating local dehydration channels. Since the molded article 1 is dehydrated to remove excess water, the molded article 1 is rapidly cured.

The molded product 1 may be cured after being removed from the mold 2, or may be cured while it is still in the mold 2. The molded article 1 may be cured at room temperature, but may also be cured by steam heating, autoclave curing, or the like. According to the present invention, the sheet placed over the molding material is expanded by reduced pressure from the outside of the mold and tightly adheres to the surface of the molded product, causing dehydration from the molded product. Almost uniform dehydration occurs throughout the product, excess water can be removed throughout the molded product, and the molded product is quickly cured.

Furthermore, since the formation of local dehydration passages is prevented, the mechanical strength of the molded product does not deteriorate. As an example mold 2, small holes with a hole diameter of 27WL are uniformly provided over the entire mold surface so as to occupy 15% of the total area of the mold surface, and the opening diameter is 300Tf! : m1 bottom diameter 150
Container-shaped containers were used with the order of height and depth of 200.

On the inner surface of this mold 2, 100 parts by weight of Bortland cement, 5 parts by weight of silica sand, 0.1 part by weight of methyl cellulose,
A mixture consisting of 1 part by weight of water reducing agent and 3 parts by weight of water and alkali-resistant glass fiber (37wn length) were sprayed to a thickness of 7W.
A molded product 1 of L was molded. From the top of the molding material, wall thickness 1T
A sheet 4 made of butyl rubber having an f0fL1 elongation rate of 450% and a tensile strength of 775 kg1d was covered. The sheet 4 was fixed to the periphery of the mold 2 by a fixing frame 5 with the middle portion slackened. A vacuum box 6 was provided outside the mold 2, and the pressure was reduced to 600 TWLHg for 3 minutes using a water ring vacuum pump. Due to the reduced pressure, the sheet 4 was brought into close contact with the surface of the molded product, and in this state, uniform dehydration occurred from the entire molded product.
After dehydration, the pressure was returned to normal, the sheet 4 was removed from the surface of the molded product, and the molded product was left in the mold for curing.
The molded product was cured quickly.

[Brief explanation of drawings]

The drawings show an embodiment of the method of the present invention, and Fig. 1 is a sectional view of the sheet covered from above the mold, and Fig. 2 is a cross-sectional view of the sheet brought into close contact with the surface of the molded product by reduced pressure. FIG.

Claims (1)

[Scope of Claims] 1. A molding material containing a hydraulic inorganic substance and water is placed in a mold having a large number of small holes and molded, and a stretchable sheet is placed over the molding material. . A method for producing an inorganic molded article, comprising: applying reduced pressure from outside of the mold to bring the sheet into close contact with the surface of the molded article, thereby dehydrating the molded article. 2. The method for producing an inorganic molded article according to claim 1, wherein the molding material contains a fibrous reinforcing material. 3. The method for producing an inorganic molded article according to claim 1 or 2, wherein the extensible sheet is made of rubber. 4. The method for producing an inorganic molded article according to any one of claims 1 to 3, wherein the extensible sheet is made of a soft synthetic resin. 5. The method for producing an inorganic molded article according to any one of claims 1 to 4, characterized in that a vacuum box is provided outside the mold. 6 Claims 1 to 5, characterized in that the peripheral edge of the stretchable sheet is fixed by a fixed frame.
A method for producing an inorganic molded article according to any one of paragraphs.