JPS586696B2 - Method for manufacturing mineral fiberboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a mineral fiberboard whose fiber components are mineral fibers such as rock wool, mineral wool, and glass wool, without using asbestos, which has an adverse effect on the human body. The present invention provides a method for producing mineral fiberboard with excellent properties such as hardness, strength, and fire resistance.

Generally, the manufacturing method of mineral fiberboard involves uniformly dispersing mineral fibers in a large amount of water equivalent to 10 to 100 times the amount of mineral fibers together with appropriate amounts of binders and additives to form an aqueous slurry.
After papermaking and molding, the wet papermaking method is used to dry and harden the paper, and 2 to 3 times as much water as the mixture is added to a mixture of mineral fibers and appropriate amounts of binders and additives. There is a paste method in which the material is kneaded into a paste, extruded or rolled to form a plate, and then dried and solidified.

In particular, the former wet papermaking method is characterized by its excellent productivity in mass production, and as one of its solid components, asbestos, which has extremely excellent retention and fixation effects for organic bond cutting, is It is necessary and essential to use the

This wet papermaking method reduces the amount of organic binder used and maintains the fire resistance of the resulting mineral fiberboard.
In addition, in order to satisfy the hardness and strength required for mineral fiberboards, the actual situation is that it is essential to use the above-mentioned asbestos as a retention and fixing material.

However, since asbestos is a natural product, the raw materials are depleted and the price is rising, and furthermore, asbestos dust may cause lung cancer, restrictions on the environment in which it can be used have been tightened. The Ministry of Labor also announced that the amount of
% or less, there is a desire for a method of obtaining mineral fiberboard using asbestos as little as possible, or without using it at all.

By having the configuration described in the claims, the present invention provides a mineral fiberboard that has excellent performance not only in fire resistance but also in hardness and strength, without using any asbestos. It provides a way to obtain

The configuration of the method for manufacturing a mineral fiberboard of the present invention will be explained below.

In the present invention, as a first step, 50 to 90% by weight of mineral fibers such as rock wool, mineral wool, and glass wool, organic binder such as pulp, raw starch, boiled starch, polyvinyl alcohol, gar gum, vinyl acetate emulsion, etc. 20% by weight, 1 to 40% by weight of attapulgite as a retention and fixing agent, and 3% by weight or less of a binding aid such as polyacrylamide, polyacrylamide modified product, aluminum sulfate, etc. as necessary. to 100 times as much water to form an aqueous slurry consisting of a dispersion of about 1 to 8% by weight of each of the aforementioned solid components dispersed in water.

As a second step, the aqueous slurry obtained in the first step is formed into paper and dehydrated using a paper making machine such as a paper mill, a circular mesh type, or the like.

Furthermore, as a final step, after the obtained paper sheet is molded, drying and curing are completed.

The method for manufacturing a mineral fiberboard of the present invention has the above-mentioned configuration, and in place of asbestos, which is used as a retention and fixing material in the conventional method for manufacturing a mineral fiberboard, acpulgite is used as a retention and fixing material. The feature is that it uses .

Acpulgite used as a retention and fixing material in the present invention is a natural product, so it is difficult to express it with a certain chemical formula, but for example, it has the chemical formula Mg5SiBO20.
It is a double-chain structure type clay represented by 4H20, etc., and has a diameter of 10
0A, it forms needle-shaped crystals with a length of about 1 to several micrometers, and has the property of dispersing colloidally in water, with a surface area of 2
It is extremely large at 10 m2/g and has high adsorption performance.

In the method for manufacturing mineral fiberboard of the present invention, the attapulgite forms a colloid in the aqueous slurry for wet papermaking, and its extremely large surface area and high adsorption performance improve the retention of the organic binder in the aqueous slurry. It has the effect of making the mineral fibers better, and it also has the effect of making the bond of mineral fibers by organic bonding even stronger.

Hereinafter, the specific structure of the method for manufacturing mineral fiberboard of the present invention will be explained with reference to Examples, and the properties of the mineral fiberboard obtained will also be explained. Compare and explain.

Examples 1 to 8 An aqueous slurry was prepared using a 4% by weight aqueous dispersion of the solid components consisting of the respective composition components listed in the Examples 1 to 8 columns of Table 1 below, and the resulting aqueous slurry was tested in a laboratory. Paper is made using a test paper making machine, dehydrated under reduced pressure, and then press molded using a press forming machine.

The obtained press moldings were dried and cured in a drying oven at 140°C for 4 hours to form 8 types of mineral fiberboards with a thickness of 12 mm (
1) to (■) were obtained.

In addition, "pulp cellulose", which is a type of organic binder in the solid component, is obtained by beating the pulp and making it into TAPPI Sta.
A stock solution of gel-like cellulose fiber with a filtration time of 400 seconds using a ndard Sheet Machine was added in an amount corresponding to a solid content of 2% by weight.

In addition, polyacrylamide as a binding agent has a molecular weight of 5
00,000 was used.

Comparative Examples 1 to 3 Aqueous slurries were prepared using 4% by weight aqueous dispersions of solid components consisting of the respective composition components listed in Comparative Examples 1 to 3 columns of Table 1 below, and thereafter operated in the same manner as in Examples. Types of mineral fiber boards (■) to (XI) were obtained.

Table 1 shows the moldability of the aqueous slurry used in the above Examples and Comparative Examples, as well as the density, bending strength, compressive strength, burning shrinkage rate, etc. of the obtained mineral fiberboard.

The moldability of each aqueous slurry was determined by molding each aqueous slurry into a wire mesh with a mesh size of 50 mesh and a wire mesh section size of 400 x 400.
This is the dewatering time when papermaking is performed using a test papermaking machine with a vacuum degree of 1500mm water column in the dewatering section during molding.

In addition, the bending strength of the obtained mineral fiberboard is JISA5
907, and the compressive strength is the value measured by compressing the fiberboard in the thickness direction at a rate of 0.5 mm/mm.
It is the value obtained by dividing the stress at 5% by the area, and the scorching shrinkage rate is the dimensional shrinkage rate (%) in the vertical and horizontal directions when the fiberboard is scorched at 800 ± 50 ° C for 1 hour. be.

From the results in Table 1, the drainage time during papermaking, which indicates the formability of aqueous slurry, increases rapidly as the amount of axapulgite added increases, but this means that the production rate decreases, and attapulgite It is clear that it is not preferable to add more than 40% by weight from the viewpoint of production efficiency.

Further, the bending strength of the obtained mineral fiberboard increases with the addition amount until the amount of acpulgite reaches 20% by weight, but conversely decreases as the addition amount exceeds 30% by weight.

It is thought that this result occurs because when the content of attapulgite exceeds 30% by weight, the ratio of mineral fibers in the fiberboard falls below 60% by weight.

The compressive strength increases as the amount of acpulgite added increases up to 40% by weight.

This is thought to be because the amount of attapulgite filled between the mineral fibers increases, making it difficult for the mineral fiberboard to be compressed.

The ignition shrinkage rate sharply improved when the amount of acpulgite added was 10% by weight.

This is thought to be because the addition of 10% by weight of attapulgite sufficiently exhibits the retention effect of the organic binder, making the bond between the mineral fibers sufficiently strong.

In addition, when compared with the case where asbestos is used as a retention and adhesion material, when the amount added is the same, the drainage time, which indicates the formability of the aqueous slurry, and the physical properties of the resulting mineral fiberboard are approximately the same. It is clear that a fully satisfactory mineral fiberboard can be obtained by using acpulgite as an alternative to asbestos retention and bonding material.

Furthermore, from the results in Table 1, it is clear that by using 20 to 30% by weight of acpulgite as a retention and fixing material, it can be used on an industrial scale without significantly deteriorating the freeness of aqueous slurry during papermaking. It is clear that it is possible to produce a mineral fiberboard having excellent properties such as bending strength and compressive strength while sufficiently maintaining high productivity.

The method for manufacturing mineral fiberboard of the present invention has the above-described structure, and does not use any asbestos, which is used as a retention and fixing material in the manufacturing of mineral fiberboard using the conventional wet papermaking method. Moreover, it is possible to produce mineral fiberboard with excellent properties such as hardness, strength, and fire resistance without reducing productivity, which is not only cost-effective but also improves the health and hygiene of operators. It also has the advantage of having multiple dogs.

Claims (1)

[Claims] 1 Mineral fiber 50-90% by weight, organic binder 2-2
An aqueous slurry obtained by dispersing in water a solid component containing 0% by weight, retention, 1 to 40% by weight of attapulgite as a fixing agent, and optionally 3% by weight or less of a binding aid. , after molding, drying,
A method for producing a mineral fiberboard, which comprises curing the mineral fiberboard.