JP2582834B2 - Papermaking method of non-asbestos calcium silicate plate - Google Patents

Description

The present invention relates to a method for manufacturing a non-asbestos extruded product of a calcium silicate plate used as an interior / exterior material for buildings and a material for ships.

[Prior art] Calcium silicate board is made by dispersing calcareous raw materials such as cement and slaked lime, siliceous raw materials such as silica paper and diatomaceous earth, and reinforcing fibers such as asbestos and pulp in water to form a slurry, and then into a round mesh papermaking. The product is dehydrated by the method, cured in an autoclave, and dried to produce a product. These products are widely used as interior and exterior materials for buildings and materials for ships because of their light weight, high strength, excellent dimensional stability, and good workability.

The use of asbestos in the papermaking process involves the adsorption of a fixed amount, the provision of drainage, and the improvement of the strength of semi-finished products (problems in handling).
It was said that stable continuous production was difficult without asbestos. In addition, asbestos plays an important role in physical properties such as strength, fire resistance, weather resistance, dimensional stability, and workability of products, and has been used as an inexpensive industrial material. However, in recent years, the carcinogenicity of asbestos has been pointed out, and its use has gradually started to be regulated, and there is also a problem of resource depletion in asbestos-producing countries. Is in a hurry. Recently, regarding the production of these round-mesh-type papermaking products, the manufacturing method of non-asbestos products consisting of pulp, wollastonite and polymer flocculant, beating pulp into fibrillated products, and using vinylon and acrylic as reinforcing fibers The same production method as above using synthetic resin, and two kinds of pulp with different beating degrees and a method using various synthetic fibers as reinforcing fibers have been proposed.

Conventionally, asbestos has been used for building materials manufactured by the round-mesh paper-making method. However, asbestos has not only been effective as a reinforcing fiber, but also has been used for continuous production such as adsorption of solids and adjustment of freeness during manufacturing. Technology that does not cause any problems has been established. At present, adsorption of solids by hydrophilic pulp, coagulation by polymer flocculant, use of wollastonite, glass fiber, and carbon fiber as reinforcing fibers are proposed. Large diameter and poor solids adsorption capacity. Therefore, there is a large amount of outflow of solids to the drainage, which hinders round-mesh papermaking because the wastewater is circulated and used. Although the use of a polymer flocculant is effective in coagulating the solid content of the slurry, it causes various problems such as stickiness of felt and contamination of drainage, and is not suitable for continuous operation. In addition, in the round-mesh type papermaking, the slurry concentration changes gradually, so it is difficult to control the amount of addition, and excessive addition has an adverse effect on the physical properties of the product. Glass fiber used as a reinforcing fiber deteriorates in a high alkali atmosphere due to autoclave curing, and its performance cannot be obtained. Carbon fiber has poor adhesion of matrix and is expensive. Not suitable for manufacturing products.

There have been proposals to beat pulp and use two types of pulp with different beating degrees together with reinforcing fibers and fillers, but these consist mainly of cement with a relatively large fineness (granularity) as a matrix. The use of slaked lime or diatomaceous earth with a small fineness (granularity) used in the manufacture of calcium silicate plates with low specific gravity and high strength is poor in solids absorption, Wastes are large and cannot withstand continuous operation.

[Problems to be Solved by the Invention] As a result of intensive studies to solve the problems related to the conventional non-asbestos calcium silicate plate production as described above, the present invention has been inexpensive and has impeded continuous production. Instead, a method for producing a non-asbestos calcium silicate plate having a high level of physical properties could be provided.

Accordingly, an object of the present invention is to provide a method for producing non-asbestos calcium silicate manufactured by a papermaking method.

[Constitution of the invention] [Means for solving the problems] The gist of the present invention is that the freeness of shopper is 80 ゜ SR or more with respect to slaked lime and diatomaceous earth raw material having small fineness (granularity) and the total dry matter. Cellulose fibers beaten into 0.5 to 3
A first step of obtaining a slurry in which solids are adsorbed to fibers by adding water so that the slurry concentration becomes 15 to 30% in a slurry concentration; and a total dry matter in other lime and siliceous raw materials. For
0.5-3% by weight of natural cellulose fibers beaten to a shopper freeness of 50-70 ° SR, 5-20% by weight of inorganic additives, 0.5-2% by weight of organic synthetic fibers to a slurry concentration of 5-10% by weight. A second step of obtaining a slurry in which solids are adsorbed to the fibers by adding water; and combining the slurry prepared in the first step and the slurry prepared in the second step while adjusting the amount as desired. After
This is a method for producing a non-asbestos calcium silicate plate, which is produced by a round-mesh paper machine.

The present invention is intended to allow the solid material used in the production of calcium silicate plate to be sufficiently adsorbed on the fiber.
The papermaking method was devised. That is, a raw material having a relatively low fineness and a raw material having a relatively high fineness, respectively.
The raw material slurries were prepared by changing the slurry concentration in two different types of natural cellulose fibers having different fibering degrees and having different beating degrees. After that, it is a method of manufacturing calcium silicate plate which is manufactured by using a round mesh type paper machine.

To further illustrate the present invention, the natural cellulosic fibers used include pulp of softwood, hardwood, cotton, hemp, waste paper and the like, pulp beaten to 80 ° SR or more with a shopper freeness (SIS-P-8121), Two types of pulp beaten to 50-70 ゜ SR are required.

The pulp used in the first step is optimally soft fibrous short-fiber hardwood pulp to perform a high degree of beating, and the addition amount of 0.5 to 3% by weight based on the total dry matter is appropriate. . At less than 0.5% by weight, solid adsorption is poor, 3% by weight
If it is added in excess of, the problem of nonflammability arises in relation to the pulp used in the second step.

These pulp must be adjusted to a slurry concentration of 15 to 30% to sufficiently adsorb fine particles such as slaked lime and diatomaceous earth.

When the slurry concentration is less than 15%, the solid content is poorly adsorbed, and when the slurry concentration is 30% or more, the dispersibility of the pulp is poor.

The pulp used in the second step needs to keep the fiber length as long as possible so that a reinforcing effect can be expected, and pulp such as hemp and cotton having high tensile strength is suitable. The appropriate ratio of pulp added to the total dry matter is 0.5 to 3% by weight.

If it is less than 0.5% by weight, solids adsorption is poor, and if it exceeds 3% by weight, its effect cannot be expected much, and there is a problem in incombustibility in relation to the amount of pulp added. There is. Since the used pulp contains a mixture of raw materials and fibers having relatively poor fineness, it is necessary to adjust the slurry concentration to 5 to 10% by weight. That is,
If the slurry concentration is less than 5% by weight, solids adsorption is poor,
A large mixer is required, which causes problems in equipment. If the content is more than 10% by weight, the dispersion of the fiber component becomes poor.

Powdered wollastonite, mica, or the like can be used as the inorganic additive. The amount to be used is optimally 5 to 20% by weight based on the total dry weight. That is, when the content is less than 5% by weight, the effect is not seen, and when the content is more than 20% by weight, the bending strength decreases.

As the fibers to be used, there are organic synthetic fibers, which must be resistant to autoclaving, and acrylic fibers and rayon fibers can be used. If the price is acceptable, it is preferable to use carbon fiber or the like. The amount used is preferably from 0.3 to 2% by weight. That is, if the content is less than 0.5% by weight, this effect is not seen.

[Action] Cellulose fibers beaten to a shopper freeness of 80 ゜ SR or more are highly fibrillated and slurried with an appropriate amount of water, so that the fiber content is well dispersed and solids adsorption and adhesion are increased. In particular, fine particles can be easily adsorbed.

If the pulp beaten to a shopper freeness of 50 ゜ to 70 ゜ SR is slurried together with the solid content in the second step, the pulp is not cut, and is not only sufficiently effective in absorbing solid content but also has a reinforcing effect. It will increase. The inorganic additive is a thermally stable substance and contributes to weather resistance, fire resistance, and dimensional stability. Conventionally, inorganic fibrous materials have been used to facilitate adsorption and adhesion to beaten pulp, and at the same time to obtain a reinforcing effect. However, in the papermaking method of the present invention, fibrous materials are used. There is no need to carry out the process, and inexpensive granules are sufficient.

In the papermaking method of the present invention, the organic synthetic fiber is necessary in terms of strength physical properties, and particularly has an effect of improving impact resistance. However, these raw materials are sufficiently dispersed and mixed in a slurry state, and are adsorbed on the beaten fibers to achieve the papermaking method of the present invention.

Next, the papermaking method of the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

[Example 1] Using 15 g of diatomaceous earth, 22 g of slaked lime and 2 g of LBKP (hardwood bleached pulp), the slurry adjusted by changing the beating degree and the slurry concentration of the pulp shown in Table 1 and changing the slurry concentration was used. The fiber was made to flow on a 60-mesh wire mesh, and the dispersion of fibers was observed for the amount of solids flowing out under the mesh and the solids on the mesh.

[Example 2] Table 2 shows 22 g of silica sand, 15 g of cement, 10 g of wollastonite (granular), 2 g of hemp pulp, and 1 g of acrylic fiber. With the slurry prepared by changing the degree of beating of the pulp and the slurry concentration, the state of dispersion of the fibers with respect to the solid content under the wire mesh and the solid content on the mesh was observed by the test method shown in Example 1.

[Example 3] Diatomaceous earth, slaked lime, LBKP (beaten to 85 ° SR freeness) using diatomaceous earth, silica sand, slaked lime, cement, wollastonat, acrylic fiber, and two types of pulp with different beating degrees.
Calculate the specified amount and mix the slurry at a slurry concentration of 20% to obtain silica slurry, cement, wollastonite, acrylic fiber, cotton pulp (beaten to a shopper freeness of 55 ゜ SR)
Are weighed in a predetermined amount, and the slurries obtained by mixing at a slurry concentration of 8% are combined to produce plate-like molded products using a round-mesh type paper making machine. After drying, the physical properties were measured. The results are shown in Table 3, that is, the mixing ratio, the papermaking condition, and the physical properties are shown.

[Effects of the Invention] The method for papermaking a calcium silicate plate of the present invention is firstly capable of producing a siliceous-calcareous molded product having excellent cosmetic properties as a building material using a noance vest paperboard product. In addition, it is possible to provide a low-cost and highly durable finish. Thirdly, it has become possible to supply non-asbestos paper-made molded products that can omit the necessity of subsequent coating application after molding. The technical effect was obtained.

Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication C04B 111: 12 (72) Inventor Tadayasu Inoue 2-66-16 Nakadori, Tsurumi-ku, Yokohama-shi, Kanagawa-ken (72) Invention Person Kenichiro Nishioka 4-16-4 Okisho, Showa-ku, Nagoya-shi, Aichi (56) References JP-A-60-99100 (JP, A) JP-A-61-53141 (JP, A)

Claims (1)

(57) [Claims] 1. A slaked lime, diatomaceous earth raw material having a small fineness (particle size) and 0.5 to 3% by weight of cellulosic fibers beaten to a freeness of 80 ° SR or more with respect to the total dry matter in a slurry concentration of 15 to 30%. % To obtain a slurry in which the solid content is adsorbed to the fiber by adding water so as to obtain a slurry content of 50% with respect to the total dry matter in the other lime and siliceous raw materials. 0.5 to 3% by weight of natural cellulose fiber beaten to ~ 70 ° SR, 5 to 20% by weight of inorganic additives, and 0.5 to 2% by weight of organic synthetic fibers are added to water to make a slurry concentration of 5 to 10% by weight and added to the fibers. A second step of obtaining a slurry in which solids are adsorbed; and adjusting the amount of the slurry prepared in the first step and the slurry prepared in the second step as desired, and then mixing Non-aqueous machine characterized by being manufactured by a paper machine Preparation of the best calcium silicate plate.