JPH09227196A - Production of hard wood chip-reinforced cement board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production process for hard wood chip-reinforced cement board which causes no warpage, cracking and delamination and can be produced in a largely shortened production time. SOLUTION: A cement composition containing a thermally hardening component, wood chips and water are mixed and they are compression-molded to form a hard wood chip-reinforced plate 3 and heat-hardened under pressurized conditions to give the objective hardened wood chip-reinforced cement plate. When the compression-molded product 3 is heat-hardened, steam is fed, as the molded product is exposed to the air at its side faces, to increase its temperature. According to this process, the temperature can be raised up to the reaction starting one in a shortened time, steam uniformly penetrates into the molded product to enable uniform temperature rising of the inside of the molded product. Moreover, since the molded product is degassed after steam treatment, spring back also can be prevented after completion of the hard wood chip- reinforced cement board.

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, and in particular, the manufactured hard wood chip cement board is free from warping, cracking, delamination and the like. The present invention relates to a method for manufacturing a hard wood chip cement board that can significantly reduce the manufacturing time.

[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. While pressure molding the mixture of to obtain a plate-shaped molded body,
The method was a method of producing a hard wood chip cement board by heating and curing the above-mentioned molded body under a pressure condition by a heating and pressing means such as a heating plate.

[0003] By the way, when a hard wood chip cement board of a normal size is manufactured by this conventional method, it takes about 6 minutes to raise the temperature of the cement up to the reaction start temperature by the method of supplying heat energy from a heating plate or the like. Therefore, there is a problem that it takes about 12 minutes including the reaction time to complete the hard wood cement board.

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

Under such technical background, the inventor of the present invention is
Focusing on the steam jet pressing method (see Japanese Patent Publication No. Sho 57-1416) that has been conventionally applied to the production of particle boards, the method is diverted to solve the above problems and a method for producing a hard wood chip cement board. Have already proposed. That is, this manufacturing method, a cement composition containing a thermosetting component, and the wood chips and water that have been shredded are mixed, to obtain a plate-shaped molded body by pressure molding the mixture, Assuming a method of manufacturing a hard wood chip cement board by heat-curing a molded body under pressure, when heat-curing the molded body that has been pressure molded, steam is supplied into this molded body to form a molded body. The method was characterized in that the temperature was raised.

Further, according to this manufacturing method, steam is supplied into the pressure-molded molded body before curing, and the temperature of the molded body is raised by the action of the thermal energy of this steam. As compared with the conventional method, it is possible to raise the temperature up to the cement reaction start temperature of the molded body in a short time compared to the conventional method, and to evenly heat the molded body because water vapor evenly enters the molded body. Will also be possible.

Therefore, when the molded body 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,
Variation in heat transfer rate in the thickness direction of the above-mentioned molded product because the manufacturing time of hard wood chip cement plate can be significantly shortened and the temperature inside the molded product can be uniformly raised by the action of water vapor. It was also a method that has the advantage of being able to prevent the warp of the hard wood chip cement plate in advance.

[0008]

By the way, when actually applying the above-mentioned manufacturing method developed by the present inventor,
Similar to the pressing method described in JP-A-7-1416, when a hard wood chip cement board is produced under a sealing condition using a steam seal or the like, cracks or delamination may occur in the obtained hard wood chip cement board. there were.

[0009] Therefore, as a result of continuous research to clarify the cause, phenomena such as cracking and delamination of the hard wood chip cement plate occur when the pressurizing conditions after completion of the hard wood chip cement plate are released. It turned out.

That is, there is a residual pressure due to the supplied steam in the completed hard wood chip cement plate, and when the above pressurizing condition is released, the springback (compressed and steam pressure due to this residual pressure is generated. Was released into the atmosphere, causing a swelling phenomenon in the thickness direction), which resulted in cracking or delamination of the cement plate.

The present invention has been made by paying attention to such a problem, and the problem is to avoid the above springback after the completion of the hard wood chip cement board and to warp the hard wood chip cement board to be manufactured. Another object of the present invention is to provide a method for manufacturing a hard wood cement plate, which is free from cracking, delamination, etc. and which can significantly reduce the manufacturing time.

[0012]

That is, the invention according to claim 1 is to mix a cement composition containing a thermosetting component with shredded wood pieces and water, and press-mold the mixture. Along with obtaining a plate-shaped molded body, on the premise of a method of producing a hard wood chip cement plate by heat curing the molded body under pressure conditions, when heat-curing the pressure-molded molded body, It is characterized in that 0.5 to 3.0 atm of steam is supplied into the molded body for 1 to 3 minutes while the side surface of the molded body is exposed to the atmosphere to raise the temperature of the molded body.

According to the method for manufacturing a hard wood cement plate according to the invention described in claim 1, as in the above-mentioned manufacturing method already proposed by the present inventor, pressure molding is performed before curing. Since steam is supplied to the molded body and the temperature of the molded body is raised by the action of the thermal energy of this steam,
When the molded body is heated and cured using a heating and pressurizing means such as a heating plate, the action of the above-mentioned steam shortens the time required to raise the temperature to the cement reaction start temperature, and the production time of the hard wood cement plate is greatly increased. Since it is possible to shorten the temperature, and the temperature of the molded body can be uniformly increased in a short time by the action of water vapor, the dispersion of the heat transfer rate in the thickness direction of the molded body is also improved and the hard wood chip cement board It is possible to prevent warpage and the like.

Further, in the method for manufacturing a hard wood chip cement board according to the first aspect of the present invention, the side surface of the plate-shaped molded body is exposed to the atmosphere, and 0.5 to 3 is contained in the molded body. Since steam of 0.0 atm is supplied for 1 to 3 minutes, it is difficult for steam pressure to remain in the molded body.

That is, the steam supplied to the molded body and having absorbed a part of its thermal energy by the molded body can be released from the side surface of the molded body into the atmosphere, and the steam is further supplied. The time is as short as 1 to 3 minutes, and the supply is completed before the side surface of the molded body is completely solidified, so that it is possible to reliably release the steam from the side surface.

Therefore, the steam pressure remaining in the completed hard wood chip cement board is reduced, and the springback after completion of the hard wood chip cement board is less likely to occur accordingly. It is also possible to prevent peeling and the like.

Next, the invention according to claim 2 relates to the invention in which the constitution of the cement composition is specified.

That is, the invention according to claim 2 is premised on the method for producing a hard wood chip cement board according to claim 1, wherein the cement composition comprises alumina cement and anhydrous gypsum or / and hemihydrate gypsum. It is characterized by containing a thermosetting component as a main component and Portland cement.

In such technical means, it is preferable to apply high temperature steam as steam to be supplied into the molded body before curing. Regarding the water vapor pressure of the water vapor to be supplied into the molded body and the supply time thereof, as described above, it is possible to release the water vapor from the side surface of the molded body, that is, the water vapor pressure: 0.5 to 3.0 atm. , Supply time: 1 to 3 minutes.

Next, in the manufacturing method of the present invention, the method of supplying water vapor into the molded body is basically arbitrary, but, for example, a steam injection board provided with a plurality of injection holes is used as an upper surface or a lower surface of the molded body. In the case of adopting a method in which the molded body is solidly adhered to the molded body, steam is supplied to the molded body by such a method, and then the steam injection pipe communicating with the injection hole of the steam injection board is released to the atmosphere to solidify the molded body. It is possible to release water vapor from the surface layer before completion through the pipe. Therefore, it becomes possible to more reliably reduce the residual pressure in synergy with the action of releasing water vapor from the side surface of the molded body.

In the invention according to claim 2, as the Portland cement constituting a part of the cement composition, as in the conventional case, ordinary Portland cement, early strength Portland cement, super early strength Portland cement, and white Portland cement are used. Etc. can be applied.

Further, any material can be applied to the woody 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.

Further, thermosetting components such as slaked lime and lime 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.

[0024]

According to the method for manufacturing a hard wood cement board according to the present invention, steam is supplied to the pressure-molded molded body before hardening, and the molded body is formed by the action of thermal energy of the steam. Since the temperature is raised, when heating and curing the molded body using the heating and pressurizing means, the heating time to the cement reaction start temperature is shortened by the action of the above-mentioned steam, and that much of the hard wood chip cement board. The manufacturing time can be significantly shortened, and the temperature of the molded body can be uniformly raised in a short time by the action of water vapor, which also improves the variation in heat transfer rate in the thickness direction of the molded body. It is possible to prevent warping of the hard wood cement plate.

Further, in a state where the side surface of the plate-shaped molded body is exposed to the atmosphere, 0.5-3.0 a
Since the water vapor of tm is supplied for 1 to 3 minutes, the steam that is supplied into this molded body and after part of its thermal energy is absorbed by the molded body is released into the atmosphere from the side surface of the molded body. Further, the supply time of water vapor is as short as 1 to 3 minutes, and the supply is completed before the side surface of the molded body is completely solidified, so that the water vapor can be surely released from the side surface.

Therefore, the steam pressure remaining in the completed hard wood chip cement plate is reduced, and the spring back after the hard wood chip cement plate is completed is less likely to occur, so that cracking or delamination of the hard wood chip cement plate is caused. It is possible to prevent it in advance.

[0027]

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 make 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 composition, 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 plurality of steam jetting boards 2 are provided, and a die 5 and a lower heating board 6 provided on the lower side of the apparatus constitute a main part of the steam jetting board 2, and the steam jetting is communicated with the spray holes 20. Water vapor is supplied via the piping 21.

Then, the raw material 3 filled in the mold 5 is
The upper heating platen 1 and the lower heating platen 6 each heated to 93 ° C. were used to compress from the top and bottom under conditions of 30 kg / cm ² and to a required thickness to obtain a plate-shaped molded body. After that, with the side surface of the molded body open to the atmosphere, 1.5 atm of steam (about 100 ° C.) is supplied from the steam jet board 2 into the molded body for 3 minutes, and then the molded body is heated under the above temperature and pressure conditions for 6 minutes. The desired hard wood chip cement board was obtained by maintaining compression (press) for a minute.

After steam is supplied into the molded body through the steam injection pipe 21, the steam injection pipe 21 is exposed to the atmosphere while the compression (press) is maintained for 6 minutes under the above temperature and pressure conditions. The release was performed, and the adjustment was made so that the water vapor was also released from the surface layer of the molded body before the completion of solidification through the vapor injection pipe 21.

Then, the bending strength (according to the bending test method of JIS A1408 building boards) of the obtained hard wood chip cement plate was measured, and the bending strength was 108 (kg / cm ² ). Moreover, when the presence or absence of warp, cracking, delamination or the like was examined in the obtained hard wood chip cement plate, it was not confirmed.

The temperature of the molded product during the production of the hard wood chip cement board was also measured. This result is shown in FIG.
It shows in (B). [Comparative Example] The same composition (raw material) used in this embodiment was applied, and the upper heating platen 1 and the lower heating platen 6 heated to 93 ° C. applied 30 kg / up / down from above and below.
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 bending strength of the obtained hard wood chip cement board was measured under the same conditions as in the above-mentioned embodiment. The bending strength was 90 to 100 (kg).
/ Cm ² ). A slight warp was confirmed in the obtained hard wood chip cement board.

The temperature of the molded product during the production of the hard wood cement board was also measured. This result is shown in FIG.
It shows in (A). [Confirmation] By applying the present invention, the production time of the hard wood chip cement plate becomes 9 minutes, and the production time can be shortened as compared with the comparative example (12 minutes), and the bending strength of the obtained hard wood chip cement plate is good. It was also confirmed that warp, cracking, delamination and the like of the hard wood cement plate are unlikely to occur.

From the graphs of FIGS. 2A and 2B, it was also confirmed that the temperature of the molded body was raised to the cement reaction start temperature in a short time by applying the present invention.

[0036]

EFFECTS OF THE INVENTION According to the method for manufacturing a hard wood chip cement board according to the first and second aspects of the present invention, the manufacturing time of the hard wood chip cement board can be significantly shortened, and the molded product is formed by the action of steam. The unevenness of the heat transfer rate in the thickness direction is also improved, which has the effect of preventing the hard wood chip cement plate from warping.

Further, the steam pressure remaining in the completed hard wood chip cement plate is reduced, and the spring back after completion of the hard wood chip cement plate is less likely to occur so that cracking or delamination of the hard wood chip cement plate is caused. It has an effect that can be prevented.

[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 a molded body temperature and time according to a comparative example, and FIG. 2 (B) is a graph showing a relationship between a molded body temperature and time when the present invention is applied. Fig.

[Explanation of symbols]

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

Claims (2)

[Claims] 1. A cement composition containing a thermosetting component is mixed with shredded wood chips and water, and the mixture is pressure-molded to obtain a plate-shaped molded body. In the method of producing a hard wood chip cement plate by heating and curing under pressure, when heat-curing the above-mentioned pressure-formed molded body, the side surface of this molded body is exposed to the atmosphere while being molded. To 0.5
A method for producing a hard wood chip cement board, characterized in that steam of ~ 3.0 atm is supplied for 1 to 3 minutes to raise the temperature of the molded body. 2. The hard wood chip cement according to claim 1, wherein the cement composition contains an alumina cement and a thermosetting component mainly containing anhydrous gypsum and / or gypsum hemihydrate and Portland cement. Method of manufacturing a plate.