JP2953808B2 - Manufacturing method of hard wood chip cement board - Google Patents

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 hard wood chip cement board mainly used for a building material such as an outer wall, and in particular, can improve various properties such as a density and a bending strength of the hard wood chip cement board. The present invention relates to a method for manufacturing a hard wood chip cement board.

[0002]

2. Description of the Related Art As this kind of hard wood cement board,
It is known that a shredded piece of wood is mixed with cement and water, the mixture is pressure-formed into a predetermined shape, and the mixture is hardened.

However, in the hard wood chip cement board, components eluted from the wood may cause the inhibition of the hardening of the cement depending on the type of the applied wood. A long time was required and the productivity was poor.

Therefore, a method of manufacturing a hard wood chip cement board which has solved these disadvantages is disclosed in Japanese Patent Publication No. 59-18339.
In the publication, a cement composition containing a portland cement and a thermosetting component mainly composed of alumina cement and anhydrous gypsum or (and / or hemihydrate gypsum) is mixed with fragmented wood chips and water. A method is described in which a mixture of the above is press-molded into a predetermined shape and heat-cured under pressurized conditions to obtain a hard wood chip cement board. In other words, in this production method, by applying the cement composition having a property that the curing speed is increased when heated to a certain temperature or more, the curing of the cement composition is performed before the hardening inhibiting component of the wood is substantially eluted. In this method, the types of wood that can be applied are expanded, the productivity is improved, and the production cost can be reduced.

[0005]

By the way, when a hard wood chip cement board is manufactured by a conventional method, as shown in the graph of FIG. 2, heat hardening is performed while maintaining the molding pressure at the highest value, or As shown in the graph of FIG. 3, when the thickness of the mixture reaches a predetermined value by pressure molding, the pressure is gradually lowered, and the mixture is heated and hardened in a state where the thickness is kept constant, so that a hard wood chip cement board is obtained. Has been adopted.

However, when a hard wood chip cement board is manufactured by such a method, a large amount of voids are present in the above-mentioned composition because a large amount of bulky wood chips are mixed therein, and the hard wood chip cement board thus manufactured is manufactured. There is a problem that air and the like are contained therein and various properties such as density and bending strength are deteriorated.

Although the characteristics can be slightly improved by setting the pressure at the time of heat curing to a higher pressure, there is a certain limit, and an expensive pressurizing device capable of generating a high pressure is newly required. There was a point.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. An object of the present invention is to provide a hard material which does not require an expensive pressurizing device and has excellent properties such as density and bending strength. It is an object of the present invention to provide a method capable of easily producing a wood chip cement board.

[0009]

That is, the present invention relates to a cement composition containing a portland cement and a thermosetting component mainly composed of alumina cement and anhydrous gypsum or (and / or hemihydrate gypsum). A method of manufacturing a hard wood chip cement board by mixing a piece of wood and water, press-molding the mixture into a predetermined shape and heat-curing under a pressurized condition. Before the mixture starts the curing reaction, the pressure is released or reduced for a short time.

When the pressure on the mixture is released or reduced by such technical means, it is desirable to heat the mixture within a temperature range in which the mixture does not undergo a curing reaction. This is because by heating, water and the like contained in the mixture can be removed with higher efficiency.

Here, as the Portland cement constituting a part of the cement composition, ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, white Portland cement and the like can be applied as in the prior art.

Further, any material can be applied to the woody material constituting the wood piece. In addition, waste materials such as chips at the end and scraps generated during the production of the hard wood chip cement board may be applied together with the woody material.

Further, slaked lime, lime, etc., which are thermosetting components, may be added as a cement composition.
A water repellent, a foaming agent, a wood chip corrosion inhibitor, a combustion inhibitor, etc. may be added. In addition to the wood chips, various aggregates, fibers and other substances may be mixed and applied for the purpose of reinforcing and increasing the amount of wood. Good.

[0014]

According to such technical means, the pressure is briefly released after the mixture of the cement composition, the fragmented wood chips and the water is press-molded and before the mixture starts the hardening reaction. Since the pressure or the pressure is reduced, moisture and air contained in the mixture can be efficiently removed from the mixture.

[0015]

Embodiments of the present invention will be described below in detail.

First, a flake having a thickness of 0.5 mm to 1.0 mm, a length of 20 mm or less, and a width of 10 mm or less is prepared from a wood chip using a flaker, and the flakes are mixed with a cement composition and water as shown below: Flake: water = 10: 3:
The mixture was mixed at a ratio of 4.5.

(Cement composition) Early strength Portland cement: 50 parts by weight Alumina cement: 15 parts by weight Hemihydrate gypsum: 9 parts by weight Slaked lime: 6 parts by weight Sodium citrate: 0.72 parts by weight The mixture was filled in a metal mold, and a hot plate having a width of 1300 mm and a length of 3000 mm heated to 80 ° C. was pressurized under the condition of 1000 ton and heated and pressurized for 3 minutes in this state. Thereafter, the pressure was released and the mixture was left for 30 seconds.

In addition, a large amount of water and the like contained in the mixture was removed by the decompression treatment, and the mixture could be filled in the mold at a higher density.

Then, the mixture was heated and pressed again at 80 ° C. and 1000 ton for 10 minutes, and then dried to obtain a hard wood chip cement board. FIG. 1 is a graph showing the change in the set pressure over time during the manufacturing process.

The obtained hard wood chip cement board was measured for its density and bending strength (according to the bending test method for building boards for JIS A1408). The density was 1.18 and the bending strength was 109 kg. /
It was cm ^2.

Comparative Example A hard wood chip cement board was manufactured under substantially the same conditions as in the example except that the same mixture as in the example was applied and the pressure was not released for 30 seconds.

When the density and bending strength of the obtained hard wood cement board were measured, the density was 1.0%.
7. The flexural strength was 87 kg / cm ² , which was inferior in characteristics as compared with the hard wood chip cement board according to the example.

[0023]

According to the present invention, after a mixture of a cement composition, a fragmented wood piece and water is molded under pressure, the pressure is released for a short time before the mixture starts a hardening reaction. Since the pressure is reduced, water and air contained in the mixture can be efficiently removed from the mixture.

Therefore, since air and the like hardly remain in the manufactured hard wood chip cement board, there is an effect that various properties such as density and bending strength of the hard wood chip cement board can be improved by a simple operation. I have.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a manufacturing time and a set pressure during the manufacturing time in Example.

FIG. 2 is a graph showing a relationship between a manufacturing time and a set pressure during the manufacturing time in the conventional example.

FIG. 3 is a graph showing a relationship between a manufacturing time and a set pressure during the manufacturing time in the conventional example.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 28/14 B28B 3/02 C04B 18/26 C04B 28/06

Claims (1)

(57) [Claims] 1. A cement composition comprising portland cement and a thermosetting component mainly composed of alumina cement, anhydrous gypsum or (and / or hemihydrate gypsum), and a fragmented wood chip and water are mixed. In a method of manufacturing a hard wood chip cement board by press-molding a mixture such as a predetermined shape and heat-curing under pressurized conditions, before the mixture starts press-curing after the mixture is subjected to a curing reaction, A method for producing a hard wood cement board, wherein the pressure is released or reduced for a short time.