JPH09235168A - Production of hard wood chip cement board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a hard wood chip cement board that has no such defects as warpage, and enables a substantial reduction of the production time. SOLUTION: This hard wood chip cement board is obtained by mixing a cement composition which contains a thermosetting component that contains alumina cement and anhydrous gypsum and/or semihydrate gypsum, and Portland cement with splintered wood chips and water, press-molding the mixture to a specified shape and successively setting the mixture by heating under pressure. This method enables rise of the temperature of the mixture up to the reaction start temperature of the cement in a short time as compared with conventional methods, and uniform temperature rise inside the mixture owing to uniform intrusion of steam into the mixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hard wood chip cement board which is mainly used for building materials such as outer walls. The present invention relates to a method for manufacturing a hard wood chip cement board that can be significantly shortened.

[0002]

2. Description of the Related Art As a method for manufacturing this kind of hard wood chip cement board, a method described in Japanese Patent Publication No. 59-18339 has been known. That is, this method comprises mixing a cement composition containing alumina cement and a thermosetting component containing anhydrous gypsum or / and hemihydrate gypsum as a main component and Portland cement with fragmented wood chips and water. In this method, a hard wood chip cement board was manufactured by press-molding the mixture into a predetermined shape and heat-curing the mixture with a heating and pressing means such as a heating plate.

[0003]

By the way, when a hard wood cement board of a normal size is produced by this conventional method, the method of supplying heat energy from a heating plate or the like raises the temperature up to the reaction start temperature of the cement. It took about 6 minutes, and it took about 12 minutes including the reaction time to complete the hard wood chip cement plate.

Further, since it is difficult to uniformly raise the temperature of the pressure-molded mixture with a heating plate or the like, it is caused by the difference in heat transfer rate in the thickness direction of the plate-shaped mixture. There is a problem that the manufactured hard wood chip cement board is likely to be warped.

The present invention has been made by paying attention to such a problem, and the problem is that the hard wood chip cement board produced does not have warp or the like and the production time can be greatly shortened. It is to provide a method for manufacturing a cement board.

Therefore, in order to solve the above problems, the present inventors have focused on a steam injection press device (see Japanese Patent Publication No. 5-57084) which has been conventionally applied to the production of wood boards such as particle boards and fiber boards. Then, we tried to convert it into a method for manufacturing hard wood cement boards. That is,
It has been found that the above problems can be improved by supplying high-temperature steam to the above mixture, which is a raw material for a hard wood chip cement plate, and performing heat curing treatment with a heating plate or the like. Further, as a result of repeating the experiment while appropriately selecting the above-mentioned steam supply conditions, it was found that a great effect can be obtained when set to a certain specific supply condition. The present invention has been completed through such experiments.

[0007]

Means for Solving the Problems That is, the present invention provides a cement composition containing alumina cement and a thermosetting component mainly composed of anhydrous gypsum and / or gypsum hemihydrate and Portland cement, and shredded wood chips. And mix with water,
Assuming a method of producing a hard wood chip cement board by press-molding these mixtures into a predetermined shape and heat-curing under pressure conditions, when heat-curing the above-mentioned pressure-molded mixture, in the mixture It is characterized in that steam is supplied to the mixture to raise the temperature of the mixture.

Further, according to the method for manufacturing a hard wood chip cement board according to the present invention, steam is supplied into the pressure-molded mixture before curing, and the temperature of the mixture is raised by the action of the thermal energy of the steam. Therefore, it is possible to raise the temperature of the above mixture to the cement reaction start temperature in a short time compared to the conventional method that does not use steam, and the steam enters the mixture uniformly, so that the inside of the mixture is evenly distributed. It is also possible to raise the temperature to.

For this reason, when the mixture is heated and cured by using a heating and pressurizing means such as a heating plate, the action of the above-mentioned steam shortens the heating time to the cement reaction start temperature,
It is possible to significantly reduce the manufacturing time of hard wood chip cement board, and because the temperature of the mixture can be uniformly increased in a short time by the action of steam, the heat transfer rate in the thickness direction of the mixture Variations are also improved, and it becomes possible to prevent warping of the hard wood cement plate.

In such technical means, it is preferable to apply high temperature steam as the steam to be supplied to the mixture before curing.

The steam pressure of steam to be supplied into the above-mentioned mixture which is a raw material for hard wood chip cement board and the supply time thereof are basically arbitrary, but the steam pressure: 0.
When the range is 5 to 1.5 atm and the supply time is 5 to 10 seconds, it is preferable because the initial temperature raising function can be exhibited without excessive water being supplied to the mixture. The invention according to claim 2 has been made for such a technical reason.

That is, the invention according to claim 2 is premised on the method for manufacturing a hard wood cement board according to the invention according to claim 1, and 5 to 10 steam of 0.5 to 1.5 atm is added to the mixture. It is characterized by supplying for a second.

In the present invention, in order to prevent water vapor supplied into the mixture which is the raw material of the hardwood cement board from leaking outside from the mixture during the heat curing of the mixture, the inside of the mold material filled with this mixture is prevented. It is preferable to provide a vapor seal which also serves as a spacer for determining the plate thickness of the mixture.

Further, as the Portland cement which constitutes a part of the above cement composition in the present invention, ordinary Portland cement, early strength Portland cement, ultra-early strength Portland cement, white Portland cement and the like can be applied as in the prior art. .

Any material can be applied to the wood-based material forming the wood piece. In addition, waste materials such as chips and end materials generated at the end of production of the hard wood chip cement board may be applied together with the wood material.

Furthermore, slaked lime, lime, etc. which are thermosetting components may be added as a cement composition, and a waterproofing agent,
A water repellent, a foaming agent, a wood piece corrosion inhibitor, a combustion inhibitor, etc. may be added, and in addition to the wood piece, various aggregates, fibers and other substances may be mixed and applied for the purpose of reinforcement and weight increase. Good.

[0017]

According to the method of manufacturing a hard wood chip cement board according to the present invention, steam is supplied to the mixture which has been pressure-molded and before curing, and the temperature of the mixture is raised by the action of the thermal energy of the steam. Since it is performed, it is possible to raise the temperature of the above mixture to the cement reaction start temperature in a short time as compared with the conventional method that does not use water vapor, and since the water vapor evenly enters the mixture, It is also possible to raise the temperature uniformly.

Therefore, when the mixture is heated and hardened by using a heating and pressurizing means such as a heating plate, the action of the above-mentioned steam shortens the heating time to the cement reaction start temperature,
It is possible to significantly reduce the manufacturing time of hard wood chip cement board, and because the temperature of the mixture can be uniformly increased in a short time by the action of steam, the heat transfer rate in the thickness direction of the mixture Variations are also improved, and it becomes possible to prevent warping of the hard wood cement plate.

According to the method for manufacturing a hard wood chip cement board according to the second aspect of the present invention, 0.5 is added to the mixture.
Since ~ 1.5 atm of steam is supplied for 5 to 10 seconds, it is possible to exhibit the initial temperature raising function without excessively supplying water into the mixture.

[0020]

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

First, wood chips are cut and crushed by a flaker and a hammer mill to prepare wood flakes, which are cement composition: water: wood flakes = 5: 2: 3 for the following cement composition and water. Were mixed in the ratio. (Cement composition) Early strength Portland cement: 79.0% by weight Alumina cement: 10.5% by weight Calcined gypsum: 6.3% by weight Fossil ash: 4.2% by weight Sodium citrate: 0.72% by weight Next, the above-mentioned mixture, which is the raw material 3 for the hard wood chip cement board, was filled in the mold 5 of the manufacturing apparatus shown in FIG. In addition, as shown in FIG. 1, this manufacturing apparatus includes an upper heating plate 1 provided on the upper side of the apparatus and an injection hole 20 for injecting steam.
, A mold 5 and a lower heating plate 6 provided on the lower side of the apparatus constitute a main part of the steam injection plate 2, and the mold 5 includes a cement plate. A spacer 4 which determines the plate thickness and also serves as a vapor seal is provided.

Then, the raw material 3 filled in the mold 5 is
The upper and lower heating plates 1 and 6 respectively heated to 93 ° C. are compressed from above and below under the condition of 30 kg / cm ² and are compressed (pressed) to a required thickness to form a raw material molding (base material). ) Is obtained, 0.5 atm of steam (approximately 100 ° C.) is supplied from the steam jet board 2 into the base material for 5 seconds, and then compression (press) is maintained for 6 minutes under the above temperature and pressure conditions. As a result, an intended hard wood chip cement board was obtained.

Next, the specific gravity and the bending strength (according to the bending test method for building boards of JIS A1408) of the obtained hard wood chip cement plate were measured. As a result, the specific gravity was 1.17 and the bending strength. Is 91 (kg
/ Cm ² ). In addition, when the presence or absence of warpage of the obtained hard wood chip cement board was examined, it was not confirmed.

The temperature of the base material (mixture of raw materials) during the production of the hard wood chip cement board was also measured. The result is shown in FIG. [Comparative Example] The same mixture (raw material) used in this embodiment was applied, and the upper heating platen 1 and the lower heating platen 6 heated to 93 ° C. were used to apply a pressure of 30 kg /
A hard wood chip cement board was manufactured by a conventional method of compressing (pressing) for 12 minutes under a condition of cm ² and raising the temperature only by heat transfer from a heating plate (that is, without supplying steam).

The specific gravity and bending strength of the obtained hard wood chip cement board were measured under the same conditions as in the above-mentioned embodiment, and the specific gravity was 1.15.
And the bending strength was 90 (kg / cm ² ). A slight warp was confirmed in the obtained hard wood chip cement board.

The temperature of the base material (mixture of raw materials) during the production of the hard wood chip cement board was also measured. The result is shown in FIG. [Confirmation] By applying the present invention, the manufacturing time of the hard wood chip cement board is 6 minutes and 5 seconds, and the manufacturing time can be significantly shortened as compared with the comparative example (12 minutes). It was confirmed that there was no difference in specific gravity and bending strength, and that the hard wood cement board did not easily warp.

From the graphs of FIGS. 2A and 2B, the base material (mixture of raw materials) is applied by applying the present invention.
It is confirmed that the temperature of 1 is raised to the cement reaction start temperature in a short time.

[0028]

According to the method for manufacturing a hard wood chip cement board according to the first aspect of the present invention, the manufacturing time of the hard wood chip cement board can be significantly shortened, and the thickness of the mixture can be increased by the action of steam. The variation in heat transfer rate in the direction is also improved, and it has the effect of preventing warping of the hard wood cement plate.

According to the method for producing a hard wood chip cement board according to the second aspect of the present invention, there is an effect that the initial temperature raising function can be exerted without excessive water being supplied to the mixture. doing.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method of manufacturing a hard wood chip cement board showing an embodiment of the present invention.

FIG. 2 (A) is a graph showing a relationship between temperature and time of a base material (mixture of raw materials) according to a comparative example, and FIG. 2 (B) Base material (mixture of raw materials) when the present invention is applied. ) A graph showing the relationship between temperature and time.

[Explanation of symbols]

 1 Upper heating plate 2 Steam injection plate 3 Raw material 4 Spacer 5 Mold 6 Lower heating plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C04B 28/16 C04B 28/16 32/02 32/02 E

Claims (2)

[Claims] 1. A cement composition containing alumina cement and a thermosetting component mainly composed of anhydrous gypsum and / or hemihydrate gypsum and Portland cement, mixed with shredded wood chips and water, and the like. In the method of producing a hard wood chip cement board by press-molding the mixture of above into a predetermined shape and heat-curing under pressure conditions, when steam-curing the above-mentioned pressure-molded mixture, steam is supplied to this mixture. A method for producing a hard wood chip cement board, which is characterized in that the temperature of the mixture is raised. 2. A steam generator of 0.5 to 1.5 atm is supplied to the mixture for 5 to 10 seconds.
A method for producing the hard wood cement plate described.