JPS5912616B2 - Wood chips, wood wool cement boards and their manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a wood piece obtained by shaping a material into a plate shape by adding a synthetic resin emulsion and/or rubber latex and water to wood pieces, wood wool, cement, and hardening the wood pieces. This invention relates to a wood wool cement board and its manufacturing method.

2. Description of the Related Art Conventionally, wood chips or wood-wool cement boards are known, which are obtained by shaping wood chips or a mixture of wood wool, cement, and water into a board shape and curing this.

The use of wood chips or wood wool cement boards is possible because they have the characteristic of being weak against tensile force, which is unique to cement boards, and are inferior in bending strength and impact resistance to plywood or particle board of the same thickness. There were restrictions on the construction site.

In addition, even after curing and hardening, these wood chips or wood wool cement boards have high water absorption or water permeability, so when they are used as exterior wall materials, for example, rainwater may infiltrate and cause the wood chips or wood cement boards to It also had the disadvantage of rotting the wood wool and the base material on which the cement board was constructed.

Conventionally, wood chips or wood wool cement boards are made by pouring wood chips or a mixture of wood wool, cement, and water into a formwork and cold-pressing them, then leaving them to naturally cure, or forming them into a board shape within the formwork. It is manufactured by steam curing, which accelerates the water hardening reaction of the cement by curing it to a degree that retains the cement, removing it from the mold, and exposing it to heated steam.

With this method, it is not possible to fill in the gaps that occur when the bond between the wood pieces or wood wool and cement is not sufficient during the manufacturing process, or the dents after drying of the mixed water that has accumulated in drops. There was a drawback that painting or printing for surface decoration could not be applied until after the remaining depressions were filled in advance with seals and the board surface was made smooth.

An object of the present invention is to eliminate such drawbacks and provide a wood piece, a wood wool cement board, and a method for manufacturing the same, which have a flat board surface, good waterproof properties, and excellent bending strength and impact resistance. .

That is, in the wood piece or wood wool cement board according to the present invention, the synthetic resin emulsion or cured rubber latex fills the recesses or gaps in the plate base material formed of the wood piece, wood hair, or cement on the board surface. This makes the board surface flat, and the synthetic resin emulsion or rubber latex that fills the recesses and gaps in the board surface becomes a dense solidified layer, which improves the waterproofing effect as well as impact resistance and bending strength. .

In addition, in this wood chip or wood wool cement board, the density of the synthetic resin emulsion or rubber latex decreases continuously from the board surface toward the center layer and is unevenly distributed.

This wood chip or wood wool cement board is made by molding a mixture of wood chips or wood wool and cement into a base material, a synthetic resin emulsion and/or rubber latex, and an appropriate amount of water in a mold into a board-like body. Rather than simply curing as in the example above, it is obtained by rapidly heating the substrate before curing to transfer the moisture in the substrate to the plate surface and evaporate it.

This will be explained below based on the illustrated embodiments.

The drawing schematically shows a cross section of a wood wool cement board that is an embodiment of the present invention.

In the figure, 1 is hardened cement, 2 is wood hair (or wood chips) scattered on the board, 3 is synthetic resin emulsion or rubber latex that fills the depressions and gaps on the board surface, and 4 is towards the center of the board. The synthetic resin emulsion or rubber latex is unevenly distributed so that the density decreases continuously.

In this wood cement board, the synthetic resin emulsion or rubber latex 2 migrates and fills the dents and gaps existing on the surface as water oozes out onto the board surface due to heating.
Moreover, since it is concentrated and solidified on the surface of the plate, the surface of the plate is flattened.

In addition, in this wood wool cement, the synthetic resin emulsion or rubber latex, which is present at a low density in the core layer inside the board, remains densely on the more hydrophilic wood chips, on the surface of the wood wool, and densely along the water migration path. and forms a network.

This cement board is manufactured as follows.

First, a material is prepared by mixing wood wool, wood chips or cement in place of it, an appropriate amount of water, and a synthetic resin emulsion, rubber latex, or one of them alone.

At this time, use a chipper or refiner to use wood chips or wood wool, such as waste wood, with a length of 10 to 45 inches! Eight width 1.5
~3.5m, thickness 0.3~Q, about 51L11L, and if it is a piece of wood, the length and width are 10~207ILrL, thickness 0
．． Appropriately crushed pieces of about 5 to 0.6 mm can be used.

As the cement, mainly Portland cement can be used, or alumina cement or blast furnace cement may also be used.

As the synthetic resin emulsion, vinyl chloride/vinyl acetate emulsion or simply vinyl acetate emulsion can be used, and as the rubber latex, methacryl butyl rubber (MBR) latex, chlorobrene latex, etc. can be used.

Regarding the mixing ratio of wood wool, wood chips, and cement, if the cement ratio is low, the bonding force between the wood chips and wood wool will be weak, and on the other hand, if the cement ratio is high, work such as cutting on hardened boards will be difficult. Therefore, the standard ratio is 3 parts of cement to 1 part of the bone dry weight of the wood wool or wood chips, but the amount can be varied within the range of 2 to 6 parts depending on the desired strength of the hardened board.

In addition, if the amount of water is too small, the fluidity of the cement will be poor and the adhesion of the wood chips and wool to the cement will be insufficient.On the other hand, if the amount of water is too large, it will be difficult to form a plate and it will take time to dry and cure. Therefore, the amount should be about 0.5 to 15 parts per 1 part of cement.

The synthetic resin emulsion or rubber latex can be mixed in an amount of 0.05 to 0.4 parts per part of cement, preferably in a range of 0.15 to 0.25 parts.

Note that the wood chips and wool are pretreated with calcium chloride (CaC1,
), ferric chloride (FeC13-6H,0), aluminum chloride (AlCl2), etc., can be mixed with other materials after immersion in an aqueous solution to speed up the setting time.

In addition, alkaline content such as sodium hydroxide (NaOH) in cement dissolves the hemicellulose of hardwood and makes it brittle, so when using hardwood as wood chips or wool, it is necessary to remove the alkali-dissolved components in advance. Alternatively, wood chips or wood wool can be treated with acid to easily neutralize alkali, or an alkali-resistant synthetic resin emulsion,
The wood chips and wool may be covered with rubber latex or the like.

On the other hand, in the case of coniferous trees, hemicellulose is not extracted with alkali unless delignification is performed, so there is no need for pretreatment as in the case of hardwoods.

The thus prepared mixed material is poured into a mold to have a uniform thickness, and then compressed and shaped using a cold press.

In this shaped board, the synthetic resin emulsion or rubber latex is uniformly dispersed within the board together with mixed water.

Thereafter, before the molded article in the mold is cured, heat treatment is applied in an infrared ray or hot air dryer to rapidly evaporate moisture in the mixture.

At this time, along with the evaporated water, the synthetic resin emulsion or rubber latex dispersed in the water moves toward the board surface and floats to the board surface, causing problems such as the distance between wood wool, wood chips, and cement, etc. It collects in the depression and becomes concentrated.

Further, the synthetic resin emulsion or rubber latex on the surface of the plate gradually loses water and solidifies, making the surface flat.

The particle size of this synthetic resin emulsion or rubber latex is about 0.25 to 2.5μ, with good quality ones being about 0.5 to 1.5μ, and the average particle size of cement is about 10μ. Therefore, it easily migrates through the interstices of cement particles.

As this synthetic resin emulsion or rubber latex moves toward the surface of the board, it remains little by little in the wall portion of the board along the migration route, forming a resin network structure.

This resin structure increases the antiseptic effect because the synthetic resin emulsion or rubber latex is more easily adsorbed to the surface of the wood chips and hair, which are more hydrophilic than cement particles, and remains covering the surfaces of the wood chips and hair.

In the plate-shaped body heated after being formed in this way, the moisture in the mixed material is evaporated, so that the water utilization reaction of the cement is interrupted and the plate-like body is in an unhardened state.

Therefore, moisture is ultimately supplied inside the plate to promote the hydration hardening reaction of the cement.

As this reaction progresses, the plate-like material becomes denser and more waterproof, and is completely cured.

In addition, even after water evaporates due to heating, the uncured cement board retains its form as a board due to the hardening of the synthetic resin emulsion or rubber latex itself, so it can be used as an exterior wall or roofing board after construction by watering or natural treatment. Rainfall may be used to cause the cement to undergo a water use reaction and harden.

In this case, cutting of the plate is easy and convenient for implementation.

Example length and width 10~20 mm, thickness 0.5~0.6 mrn
100 parts of wood chips, 300 parts of Portland cement, 1 part of water
00 parts and 60 parts of methacrylic butyl rubber latex were mixed, formed into a plate shape with a thickness of 20 mm, and then heated in an infrared drying oven at a temperature of 150 ° C for 15 minutes to evaporate moisture in the plate. After that, water was sprayed on the front and back of the board, and it was left to accumulate for 10 to 20 days and allowed to naturally cure.The wood piece had a flat surface, hardened resin parts on the front and back, and a network of resin crosslinked joints in the core layer of the board. I was able to get a cement board.

As described above, according to the present invention, it is possible to obtain a piece of wood or a wood wool cement board in which the depressions existing on the board surface are filled with resin and the board surface is flatly covered, and in addition, the board surface portion and surface layer Waterproof due to the presence of a high-density resin hardening section,
Wood chips and wood wool cement boards with increased impact resistance and bending strength can be obtained.

[Brief explanation of the drawing]

The drawing shows an enlarged sectional view of a wood wool cement board that is an embodiment of the present invention. Code explanation, 2: Wood wool (or wood chips), 3: Synthetic resin emulsion or rubber latex that fills the recesses and gaps on the board surface and leaches from the board surface, 4: Unevenly distributed in the board wall so that the density continuously decreases. synthetic resin emulsion or rubber latex.

Claims (1)

[Scope of Claims] 1. A wood piece or wood wool cement board in which a piece of wood or wood wool and cement are bonded via a synthetic resin emulsion and/or rubber latex, wherein the synthetic resin emulsion or cured rubber latex is Wood chips, wood wool on the surface,
A piece of wood or wood wool that fills the recesses and gaps of a plate base material made of cement, and is unevenly distributed such that the density continuously decreases from the surface of the board toward the center. cement board. 2 Add a synthetic resin emulsion and/or rubber latex and an appropriate amount of water to a base material of wood chips or wood wool and cement to obtain a mixture, shape this mixture into a plate in a mold, and then rapidly heat it. By this heating, the synthetic resin emulsion and rubber latex dispersed in the water inside the plate-like body are rapidly moved together with the water moving from the center of the plate-like body toward the plate surface, and a part of it is transferred to the plate-like body. The synthetic resin emulsion and rubber latex are leached from the gaps and depressions in the base material of wood chips, wood wool, and cement on the surface of the plate to fill them, and in the state of aging, the water in the plate disappears to form the synthetic resin emulsion and rubber latex. A method for producing wood chips and wood wool cement boards, which comprises curing and further adding appropriate moisture to the board to complete the water-hardening reaction of the cement.