JPH0467906A - Extrusion molding of inorganic product - Google Patents

Abstract

PURPOSE:To sufficiently keep shape retentivity after extrusion molding and to also enhance the strength of a product by adding needle-leaf tree pulp to an inorg. compound consisting of cement, silica and inorg. lightweight aerated aggregate such as pearlite and further adding water thereto to prepare a slurry with specific concn. and subjecting the slurry to extrusion molding. CONSTITUTION:5 - 20 wt.% of needle-tree pulp is added to an inorg. compound consisting of 35 - 50 wt.% of cement, 35 - 50 wt.% of silica and 5 - 10 wt.% of inorg. lightweight aerated aggregate such as pearlite and water is further added thereto to prepare a slurry with concn. of 50% or less and this slurry is subjected to extrusion molding to be formed into a predetermined product shape and the molded one is aged and cured according to a curing method. As a reinforcing fiber, 5 - 20 wt.% of needle-leaf tree pulp is added. The needle- leaf tree pulp is used because the fiber length thereof is larger than that of broadleaf tree pulp nd the strength of a product is enhanced. When the addition amount thereof is less then 5 wt.%, the strength of the product is not obtained and, when the addition amount is more than 20 wt.%, uniform mixing becomes difficult and no uniform strength of the product is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for extrusion molding of inorganic products, and more particularly to a method for extrusion molding of prize-winning products with improved extrusion performance.

[Conventional technology]

BACKGROUND ART Conventionally, extrusion molding of inorganic building materials made of cement mixtures has been very widely practiced.

Conventionally, asbestos has been commonly used as reinforcing fibers for products in this extrusion molding method, and asbestos has the advantage of not only imparting strength to the product but also imparting shape retention to the extruded product in its uncured state. Especially in extrusion molding, in addition to the above, it has various advantages such as imparting viscosity to the slurry and helping to reduce extrusion molding resistance.

However, in recent years, there has been a strong demand for restrictions on the use of asbestos or its complete abolition due to the fact that it causes pollution, and various asbestos-free cement formulations are being explored.

[Problems with conventional technology]

By the way, pulp is considered to be a promising alternative fiber for asbestos, and various proposals have been made to use the pulp fiber as a reinforcing fiber.

However, compared to asbestos, this pulp fiber is insufficient in imparting viscosity to cement slurry, and for this reason, there is a problem that an extrusion aid such as methylcellulose must be used in a larger amount than before.

In addition, it is inferior to asbestos in terms of shape retention, so to compensate for this, the concentration of cement slurry is increased, but increasing the slurry concentration impairs the fluidity of the material, making it difficult to uniformly mix the reinforcing fibers. Difficulty 4: Pulp fibers must be made using hardwood pulp fibers with a short fiber length, which is disadvantageous in terms of strength, especially Charpy impact strength, and extrusion resistance increases. The amount of addition must also be increased, which has the disadvantage that the above-mentioned problems are compounded.

(Problems to be Solved by the Invention) In view of the above-mentioned problems, this invention reduces extrusion resistance etc. when using pulp fibers in asbestos-free formulations, more easily achieves uniform mixing of pulp fibers, and The purpose of this invention is to provide an extrusion molding method for inorganic products that can maintain sufficient shape retention after molding and also has high product strength.

[Technology that led to solving the problem] That is, the extrusion molding method for inorganic products of this invention is based on 35 to 50% by weight of cement, 35 to 50% by weight of silica, and 5 to 10% by weight of inorganic lightweight foamed aggregate such as perlite. 5 to 20% by weight of softwood pulp is added to the inorganic mixture, water is added to make the slurry concentration 50% or less, the slurry is extruded and shaped into a predetermined product shape, and then according to a conventional method. It is characterized by curing and hardening.

[Function] In this invention, the amounts of cement, limestone, and inorganic lightweight foamed aggregate added are substantially the same as the amounts of the materials in the conventional extrusion molding method for inorganic products, and the following points are particularly expected in these blends: Dance.

In this invention, 5 to 241% of softwood pulp is added as the reinforcing fiber.

The reason why softwood pulp is used is that it has a longer fiber length than hardwood pulp, which is convenient for improving the strength of the product.

Further, if the amount added is less than 5% by weight, product strength cannot be obtained, and if it is more than 20% by weight, uniform mixing becomes difficult and uniform product strength cannot be achieved.

In the present invention, the slurry concentration is set to 50% or less in order to maintain uniform mixing of the above-mentioned softwood pulp into the slurry, improve fluidity of the slurry, and reduce extrusion resistance.

Note that shape retention decreases due to a decrease in the concentration of the slurry; however,
This is supplemented by the previously mentioned softwood pulp with long fiber length.

Therefore, although the slurry has a lower concentration than the conventional slurry, the addition of softwood pulp fibers improves the shape retention and increases the strength of the product.

〔Example〕

Next, this invention will be explained in detail.

40wt 1% ordinary portland cement as cement
, 40% by weight of silica sand as a silica content, 10% by weight of perlite as an inorganic lightweight foamed aggregate, and 10% by weight of softwood pulp fibers were mixed using a high-speed shear mixer, water was added to this, and the results are shown in Table 1. A concentrated slurry was produced.

As a comparative example, a slurry was produced by using a hardwood pulp instead of the above-mentioned softwood pulp, and adding 1% by weight of MC through uniformly mixed condensate and external scraping.

Table 1 The slurries of the above Examples and Comparative Examples were extruded and formed into a large number of test pieces with a thickness of 2 cm, a width of 25 cm, and a length of 30 cffl.Then, after natural curing for 12 hours, autoclave curing at 180°C for 6 hours was performed. went.

The extrusion performance, bending strength of the cured product, and Nyalpy impact test were conducted on the above Examples and Comparative Examples, and the results shown in Table 2 were obtained.

Table 2 Note 1 The unit of bending strength is dizziness/j [effect]

Claims (1)

[Claims] (1) 5 to 2% softwood pulp to an inorganic mixture consisting of 35 to 50% by weight of cement, 35 to 50% by weight of silica, and 5 to 10% by weight of inorganic lightweight foamed aggregate such as perlite.
Extrusion of an inorganic product characterized by adding 0% by weight and adding water to make the slurry concentration 50% or less, extruding the slurry to form a predetermined product shape, and then curing and hardening according to a conventional method. Molding method.