JPS5932418B2 - Manufacturing method of extrusion molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an extrusion molding material used in continuous extrusion molding of lightweight calcium silicate building materials.

Calcium silicate glue materials have excellent heat resistance, are lightweight, and have high strength, so in recent years they have attracted attention and are widely used as fireproof and noncombustible building materials.

Among them, lightweight calcium silicate building materials with an apparent density of 1.1 i'/d or less have excellent workability and heat retention properties, are extremely practical, and are rapidly increasing in demand due to their usefulness.

Conventionally, such lightweight calcium silicate building materials have been manufactured by kneading a mixed material with water and casting or press-molding the kneaded plastic material, or by paper-making a slurry. However, both require complicated operations and are inefficient.

The method of using an extruder as a means of continuously molding plastic materials is well known, but in order to use it for the production of lightweight calcium silicate building materials, it is necessary to make the raw material mixture into a suitably viscous material and then extrude it. Due to its viscosity, the compounded raw materials are strongly suppressed by the extruder's screws and blades, and are highly compressed by applying strong shearing force and pressure. There was a problem with being exposed.

Furthermore, even if lightweight aggregates used in other manufacturing methods, such as perlite and shirasu balloons, are added to reduce the weight of calcium silicate building materials, the lightweight aggregates are destroyed and the weight reduction is reduced. It is difficult to achieve the objective, and if added in such a large amount that the weight reduction effect is achieved, the strength of the molded product will drop significantly, making it unusable.

Furthermore, as a method of using an extruder, a method was attempted in which the mixed raw materials were made into a slurry, heated to gel, and then applied to the extruder, but this added strong stress to the gelled calcium silicate. As a result, the water in the hydrated gel is liberated, which significantly changes the viscosity and plasticity of the raw material composition, which may cause die clogging or breathing during extrusion, or the adhesiveness between the gels may be weak, causing the gel to leak from the die opening. It has not been put to practical use because cracks occur in the molded product when the pressure is relieved after extrusion, making it impossible to obtain a product that can be put to practical use.

As described above, there are many problems to be overcome in manufacturing lightweight calcium silicate-based building materials using an extruder. Several methods for producing lightweight calcium silicate building materials have been proposed.

However, these methods involve separately manufacturing lightweight calcium silicate under high temperature and pressure, pulverizing it, adding it to cement or quartz lime raw materials, and then curing and hardening it.
Stage preparation is being carried out.

As described above, all of these methods require more labor and time than the weight reduction methods mentioned above, or are not satisfactory in terms of weight reduction, and it is difficult to produce lightweight calcium silicate building materials by direct extrusion. It was previously considered impossible to manufacture.

In view of these circumstances, the present inventors set out to develop an industrially advantageous production method of continuously molding a lightweight calcium silicate building material with excellent physical properties and high practicality using an extruder. As a result of extensive research, especially on raw materials and their blending composition, the basic composition was cement or a mixture of cement and silica sand with fine silicon dust added, and reinforcing fibers and water were added to this. The inventors discovered that a mixture obtained by heating an aqueous slurry to gel it, adjusting the water content, adding a sizing agent, and kneading the slurry can be smoothly extruded using an extruder, and based on this knowledge, the present invention was developed. Ta.

That is, the present invention has a basic composition in which silicon dust with an average particle size of 1 μm or less is added to cement or a mixture of cement and silica sand at a ratio of 10 to 80 parts by weight per 100 parts by weight of cement; 3-4 based on weight
An aqueous slurry is prepared by adding 0 weight reinforcing fibers, optionally 3 to 150 weight aggregate and 3 to 15 times the amount of water, and the aqueous slurry is gelled at a temperature of 80 to 100°C. The resulting calcium silicate gel is then dehydrated to reduce its moisture content to 5% based on the solid content.
To provide a method for producing an extrusion molding material, which comprises adjusting the material to a range of 0 to 150% by weight, and further adding and kneading 0.2 to 3% by weight based on the weight of the basic raw material composition. .

The raw material used in the method of the present invention is added to cement or a mixture of cement and silica sand in an amount of 10 to 10% per 100 parts by weight of cement.
The basic composition includes 30 parts by weight of silicone dust.

The silicon dust used in the present invention is a fine powder substance produced as a by-product during the production of ferrosilicon, and is extremely fine spherical amorphous SiO□ with an average particle size of 1 μm or less. is used in cement in an amount of 10 to 80 parts by weight per 100 parts by weight.

If the amount used is less than 10 parts by weight, when the raw material slurry is heated to gel the calcium silicate, the expansion effect will be small and it will not be possible to obtain a building material with a low specific gravity.

In particular, the plasticity of the moisture content-adjusting raw material mixture supplied to the extruder is lost, resulting in a lack of extrusion suitability.

On the other hand, if the amount is 80 parts by weight, the raw material gel becomes too bulky due to gelation and loses its plasticity, which is not preferable since it cannot be directly molded using an extruder.

When a mixture of cement and silica sand is used in the method of the present invention, 80 parts by weight or less of silica sand is used per 100 parts by weight of cement.

Addition of silica sand improves the crystallinity of calcium silicate hydrate produced by hydrothermal reaction, but if it exceeds 80 parts by weight, the specific gravity of the molded product increases and a lightweight building material cannot be obtained.

Therefore, silica sand is not necessarily required when a low-crystalline calcium silicate hydrate is to be produced by hydrothermal curing using steam or the like.

It is necessary to add 3 to 40 parts by weight of reinforcing fibers to the above-mentioned basic composition raw material used in the method of the present invention, based on its weight.

As the reinforcing fibers, for example, inorganic fibers such as asbestos and glass fibers, or organic fibers such as pulp and polypropylene are used.

If the amount added is less than 3 parts by weight, the reinforcing effect is insufficient, and even if it exceeds 400 parts by weight, no improvement in the reinforcing effect can be expected, and a decrease in extrudability is observed. Become.

In the present invention, such a mixed composition is mixed with water to create an aqueous slurry, and this is heated to gel. When forming the slurry, it is usually 3 to 15 times the weight of the mixed composition. , preferably 7 to 10 times the amount of water is used, and the heating temperature is selected to be in the range of 80 to 100°C.

The calcium silicate in the aqueous slurry is fully gelled in about 30 minutes to 4 hours under the above heating conditions.

The aqueous gelled composition thus obtained has a calcium silicate gel with a water content of 50 to 150, based on the solid content.
It is dehydrated at 0 to 150 parts by weight.

Any means may be used for dehydration, and suction filtration or centrifugal dehydration can be advantageously employed.

If the water content deviates from the above range, it is disadvantageous because a suitable viscosity for extrusion cannot be obtained.

The preferred water content is 50 to 1200 to 120 parts by weight.The calcium silicate gel whose water content is adjusted has a water content of 0.2 to 3 parts by weight based on the weight of the basic composition in order to impart appropriate viscosity. It is necessary to add some glue.

As this paste, synthetic pastes such as methyl cellulose and polyethylene oxide are suitable.

If this amount is less than 0.2% by weight, the resulting extrusion molding material will lack viscosity and a molded product with sufficient strength will not be obtained, and if 3% by weight is used, the viscosity will become too large and the extrudability will be decreases.

This thickening agent is usually added after gel formation, but
It can also be added to the mixture before gel formation if desired.

By adding the paste in this manner and sufficiently kneading, the desired extrusion molding material can be obtained.

The extrusion molding material obtained by the method of the present invention can be made into a lightweight calcium silicate building material by molding it into a desired shape using an extruder and then hydrothermally curing it.

For hydrothermal curing, steam curing at a temperature of 60 to 100℃
48 hours and 100-210℃ in autoclave
By curing at a temperature of 6 to 24 hours, a calcium silicate building material that is lightweight and has excellent strength can be obtained.

In the method of the present invention, the adjusted raw material gel can be used inside the machine depending on its water content, the amount of glue used, the material of the wall inside the extruder, its surface condition, and the structure of the extruder. The phenomenon of sticking to the wall surface is observed.

In the present invention, such an unfavorable tendency can be improved by blending coarse aggregate as desired.

This coarse aggregate is not particularly limited as long as it does not adversely affect the production of calcium silicate hydrate during steam curing or hydrothermal treatment using an autoclave.
Perlite, coarse silica sand, limestone powder, ceramic waste powder, etc. are used.

It is necessary to mix this material in a range of 3 to 150 kg by weight based on the weight of the product.If the amount is less than this, the extrudability will not be sufficiently improved, and if it is more than this amount, the product This causes a decrease in the physical properties of the material.

In addition, coarse aggregate has a particle size of 100 μm or less,
Since a sufficient effect cannot be obtained, it is preferable that the particle size is larger than 100 μm.

However, if the particles are too coarse, they may impede the rotation of the screw in the extruder or impair the surface smoothness of the molded product. Considering that, the average particle size is usually 1~
A range of about 4 mm is preferably used.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 100 parts by weight of cement, 50 parts by weight of silicon dust, and 16.7 parts by weight of silica sand were used as raw materials, and 18.5 parts by weight of asbestos (based on the total amount of raw materials) was added to this as reinforcing fibers.
．． 1% by weight) was added, and this was added to 1480 parts by weight of water and mixed to form a slurry.

This slurry was heated to a temperature of 93±2° C. and kept at the same temperature for 2 hours to gel.

The resulting gelled liquid was dehydrated by suction filtration until the water content became 176 parts by weight (95% water content based on solid content).

1.3 parts by weight of methylcellulose (0.78% based on the total amount of raw materials) was added to the dehydrated gel composition, kneaded, and extruded using an extruder to continuously produce a plate-shaped molded product.

A part of the obtained molded product was subjected to a hydrothermal reaction at a temperature of 180°C for 8 hours in an autoclave, and the other part was heated to a temperature of 80°C using steam.
A lightweight calcium silicate building material was obtained by curing at a temperature of 18°C for 18 hours.

The properties of the products manufactured by each curing are as follows: autoclave curing has a bulk specific gravity of 0.84 (,9/ff1
), bending strength 86 floors/i, steam curing 0.86 (
, 9/) and 78tQ/ffl.

Examples 2 to 5 * Four types of extrusion molded products were produced by the same operation and treatment as in Example 1 using the blending amounts of raw materials and other components shown in Table 1 below, and each molded product was prepared in Example 1. Steam curing and autoclave curing were performed under the same conditions as above, and the physical properties of each obtained building material are also listed in the same table.

Incidentally, the whitebait used as the coarse aggregate has a particle size range of 4000 μm or less.

In addition, the water used in the slurry form was approximately 8 times the weight of the solid content, and the water content when the gelling solution was dehydrated is also shown in the table, and the gel water content is shown in parentheses in the water content column. Indicated.

Comparative Example 1 The same operation was carried out using the same composition as in Example 1, but heating and gelling of the slurry was omitted.

When the slurry was suction filtered, the water content was 59 parts by weight (water content 3 parts by weight).
2%) composition was obtained.

Add methyl cellulose to this, knead and extrude,
Building materials that were similarly cured had a bulk specific gravity of 1.8 after steam curing, and a bending strength of 110 Ky/, ff1).
Autoclave curing gives 1.6 and 152 9/i.

Comparative Examples 2 and 3 * Slurries with the two commonly used formulations shown in Table 2 were gelled in the same manner as in Example 1 to adjust the water content, and the mixture was fed to an extruder. When these materials were extruded, cracks occurred upon extrusion, and a satisfactory building material could not be obtained.

Therefore, it is virtually impossible to measure the bulk specific gravity and white discoloration on bending.

As is clear from the above description, the present invention has developed a technology that has been strongly desired in the technical field to produce lightweight calcium silicate building materials by direct extrusion molding using an extruder, but has not been able to solve the problem. This is an epoch-making invention that is extremely practical and industrially advantageous.

As a building material with excellent heat insulation and heat retention effects for energy saving,
In addition, the present invention provides a new method for molding and manufacturing calcium silicate-based structures using an extruder, which is expected to increase in demand as a non-combustible, high-strength, lightweight building material.This invention will greatly contribute to society. Thick.

Claims (1)

[Scope of Claims] 1. The basic composition is cement or a mixture of cement and silica sand, in which silicon dust with an average particle size of 1 μm or less is added at a ratio of 10 to 80 parts by weight per 100 parts by weight of cement; Based on the weight, 3 to 40 weights of reinforcing fibers and 3 to 15 times the amount of water are added to prepare an aqueous slurry, and this aqueous slurry is heat-treated at a temperature of 80 to 100°C until gelatinized, and then the obtained The obtained calcium silicate glue is dehydrated to reduce its moisture content to 50 to 50% based on the solid content.
1. A method for producing an extrusion molding material, which comprises adjusting the amount to a range of 150% by weight, and further adding and kneading 0.2 to 3 weight percent of a sizing agent based on the weight of the basic composition. 2. The basic composition is made by adding silicon dust with an average particle size of 1 μm or less to cement or a mixture of cement and silica sand at a ratio of 10 to 80 parts by weight per 100 parts by weight of cement, and based on this, 3 to 80 parts by weight based on the weight. An aqueous slurry was prepared by adding 40% by weight of reinforcing fibers, 3 to 150% by weight of aggregate, and 3 to 15 times the amount of water.
Heat-treated at a temperature of 0 to 100° C. until gelation, and then dehydrated the obtained calcium silicate gel to adjust its moisture content to a range of 50 to 150% by weight based on solid content, and further the above-mentioned base material. A method for producing an extrusion molding material, which comprises adding and kneading 0.2 to 3 weight thick paste based on the weight of the composition.