JPH07165456A - Fiber cement board - Google Patents

Abstract

PURPOSE:To obtain a fiber cement board having high strength and improved quality in high production efficiency and improved profitability by compounding cement, a specific pulp fiber material and aggregate as compounding materials. CONSTITUTION:This fiber cement board is produced by compounding a coniferous pulp fiber material with 0.5-3wt.% of a hardwood pulp fiber material having a CSF (freeness) of <=50ml to obtain a pulp fiber material, compounding the pulp fiber material with cement, silica, etc., by a compounding machine 1 to obtain a slurry 2a, supplying the slurry on a water-permeable conveyor 3 made of felt to remove excess water and form a deposit 2b on the conveyor plate, winding and laminating the deposit 2b on a making roll 4, extending the laminated fiber cement board substrate 2 and subjecting the substrate to pressing, curing, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber cement board used as a building material such as a roofing material and a wall material, and more specifically, a fiber cement board containing cement and pulp fiber material and aggregate as a compounding material. Regarding

[0002]

2. Description of the Related Art As a pulp fiber material, a pulp fiber material of coniferous wood having thick and long fibers (thickness ≈40 μm, length ≈1
5 mm) and a hardwood pulp fiber material with thin and short fibers (thickness ≈ 20 μm, length ≈ 0.2-2 mm),
The fiber material to be blended in the fiber cement board is generally a pulp fiber material of coniferous trees with thick and long fibers in consideration of the purpose of reinforcement. Conventionally, as this kind of fiber cement board, the pulp to be blended is used. Only softwood pulp fiber material was used as the fiber material.

[0003]

One of the methods for forming the fiber cement board is to supply slurry containing cement, pulp fiber material, aggregate and water onto a water permeable conveyor and pass through the conveyor. There is a flow-on method, which is a manufacturing method of removing excess water of the slurry and stacking and stacking a plurality of plate-like deposits remaining on the conveyor to form a fiber cement board. When manufacturing a fiber cement board by the conventional fiber cement board, since the pulp fiber material of thick and long softwood is used only as the pulp fiber material to be blended, excess moisture is removed through the conveyor. In addition to the water being removed, many of the active ingredients (cement and aggregates) in the slurry are also removed by passing through the pulp fiber material of the softwood. However, there is a problem that the thickness of the deposits remaining on the conveyor is thin and the strength is low. In order to manufacture a fiber cement board with a predetermined thickness, it is necessary to stack several layers. However, there is a drawback that the production efficiency is low due to the large number of laminations. Incidentally, if the slurry supply amount is increased in order to increase the thickness of the deposits remaining on the conveyor, or if the mixing ratio of the active ingredients in the slurry is increased, it takes time to remove the excess water in the former case, On the contrary, the production efficiency is lowered, and in the latter case, there is a problem that it is difficult to secure appropriate fluidity of the slurry, and it is difficult to fundamentally solve the problem.

In view of the above-mentioned drawbacks, an object of the present invention is to provide a fiber cement board which can be produced with high production efficiency.

[0005]

[Means for Solving the Problems] A characteristic constitution of a fiber cement board in the present invention for achieving this object is that a pulp fiber material of softwood and a pulp fiber material of hardwood are mixed as pulp fiber materials to be mixed. There is a place.

The hardwood pulp fiber material is C
SF is preferably 50 milliliters or less, and the blending amount of the hardwood pulp fiber material is 0.5 wt.
% To 3 wt% is preferable.

[0007]

According to the characteristic constitution of the fiber cement board in the present invention, as the pulp fiber material to be blended, the softwood pulp fiber material and the hardwood pulp fiber material are mixed, so that the softwood trees floating in the slurry are mixed. The thin and short hardwood pulp fiber materials are located between the pulp fiber materials of the above, and it becomes possible to make the gap between the pulp fiber materials of each softwood fine, and the fiber cement board is manufactured by the flow-on method. In this case, it becomes possible to make it difficult for the active ingredient in the slurry to be removed together with water. As a result, it is possible to increase the thickness of the deposit in a single slurry supply, and to manufacture a fiber cement board with a predetermined thickness, it can be carried out with a small number of laminations, improving production efficiency. It becomes possible. Moreover, by increasing the residual rate of the active ingredient in the deposit, it becomes possible to obtain a fiber cement board having high strength.

Incidentally, the pulp fiber material plays a major role in increasing the strength by exerting the characteristics as a fiber in the compound material, and is one of the values expressing the physical properties of the pulp fiber material. , CSF (Canadian Standard Freen) indicating the beating degree according to the fluffing state of the fiber
ess = freeness, which is also expressed in the unit of milliliter), and the smaller the CSF, the higher the beating condition and the larger the specific surface area of the fiber, and the larger the CSF, the lower the beating condition. However, if the CSF of the hardwood pulp fiber material is 50 ml or less, it is possible to expect a large adhesive force with cement or aggregate due to its large specific surface area, and to exhibit high strength characteristics.

In addition, for example, in the case of a roofing material made by mixing pulp fiber material, it is necessary that the roofing material has sufficient strength, and the person who works the roofing material is required because it is laid on the base plate. It is also important to have a bending characteristic that it can flexibly receive the weight even when it is placed on the laying work, and the blending amount of the pulp fiber material of the hardwood is
If it is 0.5 wt% to 3 wt%, it becomes possible to obtain a fiber cement board having suitable strength characteristics and flexibility characteristics.

[0010]

Therefore, according to the fiber cement board of the present invention, it is possible to provide a fiber cement board which has excellent strength characteristics and can be produced with high production efficiency, and improves both quality and economical efficiency. It has become possible.

[0011]

EXAMPLES Examples of the fiber cement board according to the present invention will be described below.

The present embodiment is a pulp fiber reinforced cement board for roof material, which is an example of a fiber cement board, and is manufactured by the flow-on method. Cement, silica, which is an example of aggregate, and softwood pulp fiber. And a hardwood pulp fiber as a basic compounding material and made from a slurry kneaded with water. Incidentally, by adding the silica to the basic compounding material, the silica strongly bonds with the cement in the autoclave curing of the pulp fiber reinforced cement plate, and it becomes possible to increase the overall strength characteristics.

FIG. 2 shows the production process by the flow-on method. The raw material of the pulp fiber cement board consisting of cement, silica, softwood pulp fiber, hardwood pulp fiber, and water is prepared as slurry 2a by the blending device 1. After being prepared, it is supplied onto the water-permeable conveyor 3 made of felt. Then, while being conveyed by the conveyor 3, excess water in the slurry 2a is removed by forced suction from below the conveyor 3 through the conveyor 3, and the plate-like deposit 2b remaining on the conveyor 3 is wound up on a making roll 4. Pulp fiber cement board as a product is completed through the processes of pressing, natural curing, punching, undercoating, autoclave curing, topcoating, etc. in the subsequent steps by stacking and expanding the laminated fiber cement board substrate 2. To do.

The pulp fiber cement board of the embodiment is a pulp fiber material of softwood (CSF).
= 700 ml) N and a hardwood pulp fiber material (CSF = 50 ml or less) L are mixed and formed, and as the data showing the superiority of the physical properties, the drainage concentration (suction Concentration of the active ingredient in the water content), the number of times of making (the number of turns by a making roll to obtain a fiber cement board base material having a thickness of 5.5 mm), and the interlaminar strength of the sample (pulp fiber cement board laminated The measurement results of the strength between plate-like deposits are shown in FIG. In addition, as a comparative example, FIG. 1 also shows the measurement results for a pulp fiber material to be blended that is composed of only a softwood pulp fiber material N.

As shown in the figure, according to the pulp fiber cement board of the example, the drainage concentration at the time of production is lower than that of the comparative example, and as a result, the number of times of making is reduced,
A pulp fiber cement board with high production efficiency can be obtained, and a higher value can be obtained in terms of strength characteristics.

[Other Embodiment] Another embodiment will be described below.

The aggregate is not limited to the silica described in the above embodiment, but may be, for example, mountain sand, river sand, wash sand, artificial aggregate, etc. Called wood.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 Chart showing test results

FIG. 2 is a conceptual diagram showing a manufacturing process of a pulp fiber cement board of an example.

[Explanation of symbols]

 N Softwood pulp fiber L Hardwood pulp fiber

Claims (3)

[Claims] 1. A fiber cement board containing cement, pulp fiber material and aggregate as a compounding material, wherein the pulp fiber material is a softwood pulp fiber material (N).
And a hardwood pulp fiber material (L) mixed together. 2. The fiber cement board according to claim 1, wherein the pulp fiber material (L) of the hardwood has a CSF of 50 ml or less. 3. The fiber cement board according to claim 1, wherein the content of the hardwood pulp fiber material (L) is 0.5 wt% to 3 wt%.