JPS63134546A - Cement composition for extrusion 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 (Field of Industrial Application) The present invention relates to a cement composition for extrusion molding, and more specifically to an extrusion cement composition that does not contain toxic asbestos and has excellent moldability, surface smoothness, and curing properties. The present invention relates to a cement composition for molding.

(Prior art and its problems) Conventionally, a plasticizer such as methylcellulose to impart plasticity and glass fiber to improve impact resistance are added to a mixture of cement and aggregate, and furthermore, to improve surface smoothness, Various building materials are manufactured by extruding a cement composition made by adding an appropriate amount of water to a composition mixed with asbestos and kneading the mixture to give the same, and then curing and hardening the composition.

Such a cement composition has good extrusion moldability, and molded products manufactured from it have sufficient mechanical properties such as bending strength and impact strength, and are also excellent in surface smoothness. ' However, in recent years it has become clear that the asbestos mixed in such cement compositions is toxic (reported to be a source of lung cancer, stomach cancer, etc.). During the production of the composition, it has become clear that there is a significant health risk to workers by inhaling a layer of asbestos powder.

Therefore, although the above-mentioned conventional asbestos-containing cement compositions have excellent physical properties, they have serious drawbacks that are unacceptable.

(Objective of the Invention) The present invention enables the production of molded products that have excellent moldability and curing properties, excellent surface smoothness and mechanical properties, and that does not harm the health of workers in the manufacturing process. The purpose of the present invention is to provide a cement composition for extrusion molding that can be safely produced without causing any problems.

(Structure of the Invention) The present invention comprises 100 parts by weight of cement, 1 to 10 parts by weight of alkali-resistant glass fiber, 3 to 30 parts by weight of metamorphic serpentine short fibers, 5 to 50 parts by weight of aggregate, and 0.1 to 0.1 to 100 parts by weight of plasticity imparting agent. This is a cement composition for extrusion molding, which is made by adding an appropriate amount of water to a composition of 3 parts by weight and kneading the mixture.

(Effects of the Invention) The metamorphosed serpentine short fibers, which are one of the components of the cement composition of the present invention, are composed of antibolite, which is leaf-like and plate-like, which belongs to the rock genus, and small-grained noridite, which belongs to the rock genus. It is a mixed crystal, with an accumulation of short fibers in the form of nine-fiber lamellae, and is different from chrysotile asbestos, which belongs to the serpentinite style, amosite, blue asbestos, and anthohilite, which belong to the amphibole genus. It is more flexible than asbestos and is not itself toxic. Furthermore, by being present in the water-containing composition of the present invention, this metamorphic serpentinite can impart thixotropy, suspensory properties, thickening properties, solidifying properties, etc. to the composition. It can improve moldability and significantly improve the surface smoothness of molded products.

Furthermore, the uninvented compositions do not contain asbestos and can therefore be produced safely.

(Preferred Embodiment of the Invention) In the present invention, as the cement, portland cement, blast furnace slag cement, alumina cement, fly ash cement, sulfate cement, and other various cements can be used.

Examples of alkali-resistant glass fibers include glass fibers with improved alkali resistance, such as Mineron
Product name] is used. The amount of alkali-resistant glass fiber used is 1 to 10 parts by weight per 100 parts by weight. If the amount of glass fiber used is less than the above range, the strength of the extruded product will be reduced, and if it is more than the above range, the moldability of the composition will be reduced.

Further, metamorphosed serpentinite short fibers are a mixed crystal of undef9ite and rhizodite, and the initially formed serpentinite is processed through subsequent metamorphism to become metamorphosed serpentinite. Its main component has the following structural formula (%), and short fibers are accumulated to form a leaf-like antibolite shape.

Its solubility in inorganic acids is, for example, about 40 ts when boiled in 5-thihydrochloric acid for 60 minutes, which is about the same as that of clittile asbestos (about 38 ts), but its solubility in organic acids is, for example, 50 ts. When stirred in an acid aqueous solution for 60 minutes, the concentration is approximately 5%, which is higher than that of clittile asbestos (approximately 0.3%), and due to its solubility in organic acids, it is not toxic to the human body. I think that the. The metamorphic serpentine short fibers are preferably pulverized before being incorporated into the composition of the present invention.

Its membrane properties are as follows.

Chemical composition (1 example) SIO239.9% by weight Mg0 46.3 # Az2o5 4.2 # Na2O0,6' to 20 0.03〃'rto2 0.021 Hue Pale green gray Water content (ch) 0.5~ 1.6-(20 powder solution after 2 hours) 9.8-10.1 Oil absorption (flax $/100p) 40-80 Electron specific gravity (statement) 0.2-0.6 Particle size distribution (1 example) 74μ Keto 70.0A 46μ# 50.0% 20μtt 29.3% 10μtt 26.8% 5μ 7 21.0% 2μm 14.3 The amount of metamorphic serpentine short fiber used is 100 parts by weight. On the other hand, it is 3 to 30 parts by weight, preferably 5 to 20 parts by weight. If the amount of metamorphic serpentine short fibers used is less than the above range, the extrudability of the composition will be reduced and the surface smoothness of the molded product will be poor; becomes impossible.

Further, as the aggregate, ordinary aggregates such as river sand, silica sand, perlite, etc., which are passed through a Tyler standard 16-mesh sieve, and Schuander can be used. The amount of aggregate used is 5 parts per 100 parts by weight of cement.
50 to 50 parts by weight, preferably 10 to 30 parts by weight; if it is less than the above range, dimensional stability and weight reduction will not be achieved, and if it is more than the above range, extrudability and bending of the molded product will be impaired. Strength decreases.

Further, as the plasticity imparting agent, for example, polyvinyl alcohol; polyethylene glycol; polypropylene/glycol; cellulose derivatives such as methyl cellulose and carboxymethyl cellulose; polyacrylamide, etc. are used. The amount of plasticizer used is 0.1 to 3'M parts per 100 parts by weight of cement.

The cement composition for extrusion molding of the present invention is prepared by sufficiently mixing the above cement, alkali-resistant glass fibers, metamorphic serpentine short fibers, aggregate, and plasticizer in a dry state, adding an appropriate amount of water, and kneading. Manufactured by The amount of water used cannot be set uniformly because it varies depending on the usage ratio of each component and extrusion conditions, but it is generally 20 to 100 vf per 100 parts by weight of water.
It is preferably within the range of L parts.

The extrusion molding machine used for extrusion molding the cement composition of the present invention includes a twin-screw screw for kneading the raw material composition, a mixing part consisting of a cylinder and a cylinder, and a degassing part for degassing the air in the composition. It is composed of a round vacuum chamber for extrusion, a compression section for applying extrusion pressure, and a molding die for molding the composition into a predetermined shape. The cement composition of the present invention can be molded into a molded article having a desired shape by a method known per se using such an extrusion molding machine.

Example 1 The following ingredients Cement: Ordinary Portland cement Alkali-resistant glass fiber: Mineron [manufactured by Cria 71=, trade name] Metamorphosed serpentine short fiber Niikuton [Yuta Chikara Sangyo Co., Ltd.] Aggregate: No. 5 Silica sand malleable filler: Methyl cellulose is used in the amounts listed in Table 1, and thoroughly mixed in a dry state using a kneader. To this, 30 parts by weight of water is added and kneaded to obtain extrusion molding cement. A composition was produced.

These cement compositions are supplied to the raw material charging port of the extrusion molding machine, mixed at the cross-wire section, and then sent to the vacuum chamber at a pressure of 60
It was degassed under a reduced pressure of smH1r or less, then sent to a compression section, extruded from a die, placed on a roller conveyor, and taken back.A flat plate having a rectangular cross section of 10 mm long and 60 mm wide was manufactured. The molding conditions are shown in Table 1. After this plate was cured in steam at 65° C. for 4 hours and in water for 28 days, its physical properties were measured.

The results are shown in Table 1.

Comparative Example 1 A flat plate was produced in the same manner as in Example 1, except that the ingredients and the amounts used were changed as shown in Table 1. Table 1 shows the physical properties of the plate cured in the same manner as in Example 1.

Claims (1)

[Claims] (1) 100 parts by weight of cement, 1 part of alkali-resistant glass fiber
10 to 10 parts by weight, 3 to 30 parts by weight of metamorphic serpentine short fibers,
5 to 50 parts by weight of aggregate and 0.1 to 3 parts by weight of plasticizer
A cement composition for extrusion molding, characterized in that it is prepared by adding an appropriate amount of water to a composition consisting of parts by weight and kneading the mixture.