JPH0840761A - Production of thick plate for architecture - Google Patents

Abstract

PURPOSE:To produce a thick plate for architecture, having a high strength and a low specific gravity at low cost. CONSTITUTION:This is a method for producing a plate by dispersing a raw material containing pulp fibers and cured cement materials in water to prepare a slurry, forming a plate from the resultant slurry, dehydrating, pressing, curing and hardening it. In this production method, the raw material contains the pulp fibers in an amount of at most 30 to 60wt.% and the cured cement materials in an amount of at least 70 to 40wt.%. Pulp fibers subjected to beating treatment, e.g. by a refiner are used as the pulp fibers in the raw material and a high pressure of 100 to 300kgf/cm<2> is used in the pressing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a building plank such as a floor material, a concrete formwork, a floor or roofing base material.

[0002]

2. Description of the Related Art When manufacturing a fiberboard of a building plank by a wet method, a slurry of pulp fibers is made into paper, dehydrated, hot pressed,
The pulp fiber is bonded by raising the temperature of lignin and the like in the pulp fiber. Further, when the fiberboard is manufactured by a dry method, an adhesive is mixed with the pulp fiber and the pulp fiber is hot pressed to bond the pulp fiber with the adhesive.

Further, in the case of manufacturing a pulp cement board for building planks, a small amount of pulp fiber of 10% by weight or less and 80
A slurry is prepared by dispersing a raw material containing a large amount of cement hardening substance in an amount of not less than wt% in water, dehydrated, compressed under a low pressure of 30 kgf / cm ² or less, and cured to harden.

[0004]

It is desired that a building slab have high strength, light weight, and low cost.

However, when the above fiberboard is manufactured by a wet method, in order to increase the strength, in order to raise the core temperature of the thick plate to a predetermined high temperature, the hot pressing time becomes long, the manufacturing efficiency is poor, and the construction is poor. Cost plate becomes expensive. Further, when the fiberboard is manufactured by a dry method, a large amount of adhesive is required to increase the strength of the plank, the hot pressing time becomes long, and the plank for construction becomes expensive.

Further, in the case of manufacturing the above-mentioned pulp cement board, the pulp cement board has a large amount of light pulp fibers and a large amount of a heavy cement hardening substance, so that the specific gravity is large and heavy. Furthermore, since it has a structure in which pulp fibers are dispersed in the cement hardening material, it is heavy but not so strong.

An object of the present invention is to solve the above conventional problems.

[0008]

Attention and Experiments for Solving the Problems First of all, the present inventor uses a cement hardening substance, which is cheaper than an adhesive, as a binder for pulp fibers and heats it during pressing, as in the method for producing a pulp cement board. We decided to adopt a wet papermaking method that does not require it and that tends to make the plate thickness uniform.

Therefore, in order to reduce the weight of the building plank,
As a raw material, we tried to manufacture planks by increasing the mixing ratio of pulp fiber, which is lighter than the cement hardening material. However, if the mixing ratio of the pulp fiber in the raw material is increased, the mixing ratio of the cement hardening substance in the raw material decreases, so that the plank plate has pulp fibers dispersed in the cement hardening substance like a pulp cement board. Instead, the cement hardening substance is dispersed between the pulp fibers, the strength due to the hardening of the cement is not obtained, only the strength due to the entanglement of pulp fibers,
It was difficult to make a plate, and a thick plate with high strength could not be obtained. Also, many voids were formed between the pulp fibers.

Therefore, in order to eliminate the voids between pulp fibers and to increase the strength of the planks, the pressing pressure after papermaking dehydration was increased. However, when the clamping was released, springback occurred and the strength of the plank did not increase so much.

Then, the pulp fiber was used after being beaten with a refiner. Then, the springback after releasing the pressure was reduced, and the strength of the plank was increased.

The reason for this is presumed as follows. The beating pulp fibers have whisker-like minute fiber hairs branching on the surface, and the surface viscosity increases. Therefore, when the pressing pressure is high, the surfaces of the pulp fibers come into contact with each other, and the pulp fibers are easily bonded to each other due to the entanglement of the fine fiber hairs on the surface and the adhesion of the surfaces, and the bonding force between the pulp fibers is increased. Further, the amount of the cement hardening substance captured on the surface of the pulp fiber increases, and the binding force of the pulp fiber by the cement hardening substance increases. Further, the high-pressure compaction increases the amount of excess water squeezed out, the water-cement ratio becomes appropriate, and the hardening reaction of cement becomes active.

[0013]

Means for Solving the Problems The present invention provides a method for producing a plate in which a slurry in which a raw material containing pulp fibers and a cement hardening substance is dispersed is made into paper, dehydrated, pressed, cured and cured. The raw material has a pulp fiber content of 30 to 60% by weight and a cement hardening substance content of 70 to 40% by weight, and the pulp fiber in the raw material is subjected to a refining treatment such as being applied to a refiner. , Canadian standard freeness is 100 to 400 ml, and the pressure for clamping is 100 to 3
This is a method for manufacturing a building slab characterized by a high pressure of 00 kgf / cm ² .

[0014]

In the present invention, the pulp fiber content in the raw material is high and the cement hardening substance content in the raw material is low, so that a building plank having a small specific gravity can be obtained.

When the amount of pulp fibers in the raw material is small and the amount of cement hardening substance is small, it is difficult to obtain a thick plate having high strength. However, the pulp fibers in the raw material have been beaten, and the compression pressure is high. Therefore, a building board having high strength can be obtained.

Further, since a cement hardening substance, which is cheaper than an adhesive, is used for the binder of pulp fibers and heating is not required at the time of pressing, a building plank can be obtained at low cost.

Since it is a wet papermaking method, it is easy to obtain a building plank having a uniform thickness.

[0018]

According to the present invention, a building plank having high strength and low specific gravity can be obtained at low cost.

[0019]

EXAMPLE In the method for manufacturing a building slab of this example, pulp fiber is 30 to 60% by weight and cement hardening material is 70 to 40% by weight.

The pulp fibers in the raw material have been subjected to a beating treatment with a refiner and have a Canadian standard freeness (JIS P8121) of 100 to 400 ml, more preferably 150 to 300 ml. The pulp fiber has a Canadian standard freeness of 700 ml or more when it is not beaten. The pulp fiber in the raw material is a bleached pulp fiber and contains no unbleached pulp fiber, or the content of the unbleached pulp fiber in the raw material is 20% by weight or less.

The cement hardening substance in the raw material is cement and silica sand, or pearlite or the like is added to it. The weight ratio of cement and silica sand is 1.5: 1 to 1: 1.
It is 1.5.

The raw material slurry is prepared by dispersing the above raw materials in water to a concentration of 3 to 6%.

In the Fourdrinier papermaking machine, the raw material slurry is
It flows down from the flow box onto the paper making net, is dehydrated and made into a thin film to form a web. The web is
Each time the paper is taken up from the making net on a making roll and wound in multiple layers to a predetermined thickness, the web wound in multiple layers is cut and peeled off from the making roll, spread on a mat and placed on a conveyor. To fall. The mat body is inserted into a flat plate press by a conveyor and clamped at a high pressure of 100 to 300 kgf / cm ² . After that, it is cured through primary curing and secondary curing by an autoclave, and dried. 10 to 30 mm thick
Manufactures architectural planks.

When the autoclave is cured, the hardening reaction of the cement hardening material is promoted, and the strength of the building plank increases.

<Examples 1 to 3 and Comparative Example 1> By changing the blending ratio of the pulp fiber and the cement hardening substance in the raw material to each value,
Produced architectural planks. Pressure of mat body (250kg
f / cm ² ) and temperature of secondary curing by autoclave (18
Other conditions such as 0 ° C.) are constant. The specific gravity and bending strength of each building plank were measured. It shows in Table 1.

[0026]

[Table 1] As is clear from Table 1, in Examples 1 to 3, the raw materials contained a large amount of pulp fibers and a small amount of a cement hardening substance,
Building planks have low specific gravity and high bending strength. On the other hand, in Comparative Example 1, the raw material has a small amount of pulp fibers and a large amount of a cement hardening substance, and the construction plank has a large specific gravity and a low bending strength.

<Examples 4 to 7 and Comparative Example 2> By changing the clamping pressure to each value, a plank for construction was manufactured. Other conditions such as the mixing ratio (35:65) of the pulp fiber and the cement hardening material in the raw material and the temperature of the secondary curing by the autoclave (180 ° C.) are constant. The specific gravity and bending strength of each building plank were measured. It shows in Table 2.

[0028]

[Table 2] As is clear from Table 2, in Examples 4 to 7, the clamping pressure is high, and the construction plank has low specific gravity and high bending strength. On the other hand, in Comparative Example 2, the pressing pressure is low and the plate is not manufactured.

<Examples 8 to 11> Construction planks were manufactured by changing the amount of the cement hardening substance in the raw material to be replaced with pearlite to each value. Mixing ratio of pulp fiber in raw material (35
% By weight), clamping pressure (250 kgf / cm ² ), temperature of secondary curing by autoclave (180 ° C.), and other conditions are constant. The specific gravity and bending strength of each building plank were measured. It shows in Table 3.

[0030]

[Table 3] As is clear from Table 3, in Examples 8 to 11,
As the amount of the cement hardening material in the raw material replaced with pearlite increases, the building plank has a lower specific gravity and a lower bending strength.

<Examples 12 to 14> The amount of the unbleached pulp fiber in the raw material to be replaced with the unbleached pulp fiber was changed to each value,
Produced architectural planks. Other conditions such as the mixing ratio (50% by weight) of the cement hardening material in the raw material, the pressing pressure (250 kgf / cm ² ) and the temperature of the secondary curing by the autoclave (180 ° C) are constant. The specific gravity and bending strength of each building plank were measured. It shows in Table 4.

[0032]

[Table 4] As is clear from Table 4, in Examples 12 to 14, even if the bleached pulp fiber in the raw material is replaced with the unbleached pulp fiber, the building plank has little change in specific gravity,
Bending strength changes. 10 unbleached pulp fibers in the raw material
In Example 13 in which the weight% is obtained, the flexural strength of the building plank is higher than that in Example 12 in which there is no unbleached pulp fiber, but the unbleached pulp fiber in the raw material is 15% by weight. In Example 14, the building plank has a low bending strength.

The unbleached pulp fiber has the advantage that the strength of the fiber is higher than that of the unbleached pulp fiber to increase the strength of the building plank and the strength of the building plank is lowered by inhibiting the hardening of cement. With disadvantages, the higher the proportion of unbleached pulp fiber, the more the disadvantages outweigh the advantages. The building board contains 20% by weight of unbleached pulp fiber in the raw material.
The following is desirable.

<Experimental example> The relationship between the pressing force of the mat body and the specific gravity of the building plank was determined. As is clear from FIG. 1 showing this relationship, even if the compression pressure of the mat body is increased to about 50 kgf / cm ² , the specific gravity of the building plank does not become so large, and springback occurs. It is guessed that.
However, when the clamping pressure increases beyond about 50 kgf / cm ^2, it is presumed that the building plank has a sharply increased specific gravity and no springback occurs.

The relationship between the pressing pressure of the mat body and the spring back ratio was determined for the case where the pulp fiber in the raw material was beaten and the case where it was not beaten. As is clear from FIG. 2 showing this relationship, when the pulp fibers are beaten, the springback rate of the pressed mat body is lower than when the pulp fibers are not beaten. Especially, the clamping pressure is 1
When it exceeds about 100 kgf / cm ² , the springback rate increases when the pulp fiber is not beaten, but when the pulp fiber is beaten, the springback rate does not increase and remains almost constant. is there.

The relationship between the pressing pressure of the mat body, the water content, and the water-cement ratio was determined when the content of pulp fiber in the raw material was 35% by weight and the content was 10% by weight. It shows in Table 5.

[0037]

[Table 5] As is clear from Table 5, when the content of pulp fiber in the raw material is as high as 35% by weight, the water-cement ratio of the mat body is too large when the pressing pressure of the mat body is about 50 kgf / cm ^2. It is not suitable for the hardening reaction of cement, but when the pressing pressure reaches 100-300 kgf / cm ² , the mat body
The amount of excess water squeezed out increases, the water-cement ratio becomes appropriate, and the hardening reaction of cement becomes active.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a pressing force of a mat body and a specific gravity of a building plank in a method of manufacturing a building plank.

FIG. 2 is a diagram showing the relationship between the pressing pressure of the mat body and the springback rate when the pulp fiber in the raw material is beaten and not beaten in the method for manufacturing a building slab.

Claims (3)

[Claims] 1. A slurry in which a raw material containing pulp fibers and a cement hardening substance is dispersed in water is made into paper, dehydrated, and compressed,
In the method for producing a plate that is cured and hardened, the raw material is 30 to 60% by weight of pulp fiber and 70 to 40% by weight of cement hardening substance, and the pulp fiber in the raw material is beaten. The method for manufacturing a building slab according to claim 1, wherein the clamping pressure is 100 to 300 kgf / cm ² . 2. The pulp fiber in the raw material is subjected to a refining treatment with a refiner to have a Canadian standard freeness of 100 to 400 ml.
The method for manufacturing a building slab according to claim 1, wherein: 3. The pulp fiber in the raw material is a bleached pulp fiber and contains no unbleached pulp fiber, or the content of the unbleached pulp fiber in the raw material is 20% by weight or less. The method for manufacturing a building plank according to claim 1 or 2.