JPH0448322B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing particle board, and in particular, it has good cushioning properties, heat retention, sound insulation,
This invention relates to a cushion board (mat) with a three-layer structure that has excellent vibration-proofing effects and excellent performance as a flooring material for housing construction materials. [Prior art] Particle board, which is obtained by hot-pressing wood chips with adhesive, has the characteristics of high utilization of wood resources and the ability to obtain uniform long products.
In recent years, it has been widely used for building materials, furniture materials, automobile interior materials, etc. Conventionally, resin-based adhesives such as urea-based, phenol-based, melamine-based, and isocyanate-based resins have been used as adhesives for manufacturing particle boards (Japanese Patent Laid-Open No. 57-207058).
In some cases, a curing agent may be added to accelerate curing, and when applying the adhesive, it is necessary to apply the adhesive to the entire surface of the small piece so that a layer of minimum thickness is applied. One of the requirements for coating was to apply the product evenly [June 30, 1981, published by Maruzen Co., Ltd., "Wood Industry Handbook", pages 665-701]. Therefore, particle board has completely different properties such as flexibility, elasticity, cushioning properties, and durability, and has almost no application in fields requiring such properties. [Problems to be Solved by the Invention] The present invention is a particle board, in particular, a rubber-like particle board that is flexible, has excellent bending resistance, and has rebound elasticity,
The aim is to provide products with excellent durability. Another object of the present invention is to provide a wooden cushion pine that has both the properties of wood and the flexibility of rubber, has excellent heat retention, sound insulation (sound absorption) properties, and vibration proof properties, and is suitable as a housing building material. The above and other objects and novel features of the present invention will become apparent from the description herein. [Means to be Solved by the Invention] and [Operation] The present invention provides a method for manufacturing a laminated particle board made of wood material, in which a conjugated double bond is used as an adhesive before forming the surface layer of the board. The main ingredient is a mixed latex obtained by mixing one or more types of synthetic rubber latex obtained by copolymerization or homopolymerization by emulsion polymerization, or by replacing a part of the synthetic rubber latex with natural rubber latex, with the main composition being a monomer having As,
An adhesive (latex adhesive) made by adding at least an additive necessary for vulcanizing the rubber component in the latex to the base material (latex adhesive) is used, and the latex adhesive is applied to particles such as wood chips. Applying an excessive amount of coating to the chips in excess of the amount required for adhesion between the board raw materials (chips), while prior to forming the inner layer of the board,
As an adhesive, the latex adhesive may be used as it is, or one or more of a foaming agent, thickener, and filler may be added thereto and stirred at high speed to foam, followed by delayed gelling. applying a foamed latex adhesive mixed with a foamed latex adhesive to the inner layer chips, which include more coarse chips than the surface layer chips;
Next, using the inner layer chip coated with the foamed latex adhesive and one or more surface layer chips coated with the foamed latex adhesive, these chips are laminated into at least a two-layer structure, and then the laminate is laminated. The present invention relates to a method for manufacturing a laminated particle board made of wood material and having cushioning properties characterized by being formed by hot pressing. The effects of the present invention will be briefly explained as follows along with an overview of typical features of the present invention.
That is, in the present invention, when manufacturing particle board, a latex adhesive made of synthetic rubber latex or the like with a composition of 70% or more of monomers having conjugated double bonds (diene bonds) is used, and wood, which is the raw material of particle board, is used. By applying an excessive amount of adhesive to the chips, exceeding the amount required to bond the chips, the necessary adhesive layer is formed between the chips, and the excess adhesive is allowed to reach the inside of the chips. The surface layer of the particle board has a rubber elasticity that makes the chip wood flexible and has a resilient force.
Furthermore, durability can be increased by vulcanization of the latex adhesive, and a particle board surface layer similar to that of rubber products can be obtained. The particle board according to the present invention is of a laminated type, and is constructed into a laminated mat-like material using such surface layer parts.
For example, a three-layer structure is constructed in which the surface layer has two surfaces, front and back, and an inner layer as described below is interposed in the middle layer. A similar latex adhesive is used for the inner layer, but a foaming agent is used in the adhesive, and the adhesive is stirred at a high temperature to foam. At this time, a delayed gelling agent is added in order to develop an appropriate gelling effect and to coat the chip surface with a stable solidified (gelled) rubber foam layer. The inner layer chips and surface layer chips that have been coated with adhesive are hominated to form a three-layered mat, which is then hot pressed using a press. Since the chips for the inner layer (middle layer) are larger than the chips for the surface layer, the spaces between the chips are filled with an elastic rubber foam. The particle board thus obtained has cushioning properties that are pleasant to the touch, and has excellent heat retention, soundproofing, and vibrationproofing properties, and is suitable as a housing building material. Next, the structure and operation according to the present invention will be explained in further detail along with preferred embodiments. As the chips (raw material for particle board) used in the present invention, various types used for general particle boards can be used. The raw material for particle board is generally referred to as wood chips or particles. In the present invention, it is preferable to use wood chips obtained by cutting or crushing wood as the raw material. A part of the wood chips may be replaced with particulate or fibrous inorganic material. Chips are preferably dried to a moisture content of 10% or less. Preferably, the chips are matched in shape and size. It is also preferable that the applied latex adhesive be uniformly wetted and evenly softened during hot pressing, and that it forms a homogeneous matrix layer through stable forming and has a strong elastic surface. From this point of view, the surface layer chips are needle-like or flake-like in shape, and have a size selected to pass through a 30-mesh sieve but not pass through a 60-mesh sieve. It is preferable that it is mainly composed of. The surface layer chip uses a smaller chip than the inner layer chip described later. The surface layer chip has a length of 0.5 to 5 m/m and a thickness of 0.1 to 0.7
It may be m/m. The latex adhesive used in the present invention is mainly composed of synthetic rubber latex. Examples of the synthetic rubber latex include latexes of butadiene rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber (SBR), and acrylonitrile-butadiene rubber. Synthetic rubber latex has a composition of 70% or more of monomers with conjugated double bonds (diene bonds), and is obtained by copolymerization or homopolymerization using emulsion polymerization. When used, the flexibility and rubber elasticity of particle board can be obtained. . Synthetic rubber latexes have different latex properties and rubber component characteristics depending on the type of monomer having a conjugated double bond or the properties of other copolymerized monomers. Therefore, it has appropriate flexibility to suit the purpose of use, has excellent rebound resilience, and has improved durability, water resistance, heat resistance, oil resistance, etc., as well as workability and price. It is better to use a mixture of two or more types of rubber latex. A portion of the synthetic rubber latex may be replaced with natural rubber latex. In the present invention, synthetic rubber latex or a mixed latex obtained by mixing this with natural rubber latex as described above is used as the main ingredient, and various additives are added thereto as necessary. In the present invention, a latex adhesive is used, and in order to vulcanize the rubber component in the latex, obtain the necessary vulcanization effect, and give the board durability,
It is preferable to disperse a vulcanizing agent with a vulcanizing effect in the latex. As the vulcanizing agent, commercially available sulfur powder for rubber vulcanization and the like can be used. A vulcanization accelerator or vulcanization aid may be used in combination. Depending on the type of synthetic rubber latex, etc., these alone can have a vulcanizing effect. For example, a vulcanizing aid such as zinc white powder acts as a vulcanizing agent for carboxy group-modified SBR, nitrile rubber, chloroprene rubber latex, and the like. Various types of vulcanization accelerators can be used; for example, thiazole-based commercial products with the product symbol MZ, or dithiocarbamate-based commercial products with the product symbols EZ and PX can be used. Can be done. In the present invention, it is preferable to use an antiaging agent to prevent aging of the latex. Specific examples include phenolic anti-aging agents. It is preferable that the vulcanizing agent, vulcanization accelerator, vulcanization aid, and anti-aging agent be well dispersed in water before use. Next, an example of a method for producing a latex adhesive and a preferred range of the amount of the additive used will be shown. The manufacturing order is to put the required latex into a mixer. When preparing a mixed latex, 0.5 to 1% of potassium oleate is added to the latex and mixed with stirring. Add each additive while operating the mixer: 1% to 2% anti-aging agent, 1% to 1% vulcanization accelerator.
5%, vulcanizing agent (sulfur) 2 to 3%, and vulcanization aid (zinc white) 2 to 6%, and stir and mix. (The percentage value is the usage ratio (wt) to latex)
). By completing stirring and mixing, a latex adhesive is obtained. It is preferable to add a flame retardant to the adhesive in order to make the particle board flame retardant. Examples of flame retardants include antimony oxide-based, halogen compound-based, and phosphoric acid compound-based flame retardants. Further, a preservative, a waterproofing agent, an anti-termite agent, etc. may be added to the adhesive. Applying latex adhesive to the surface chip is as follows:
For example, the chips may be placed in a coating machine called a blender and applied by a spray method. Generally, in the manufacturing method of particle board, the amount applied is 15% of the solid content of the adhesive based on the weight of the chips.
(wt) Adhesive is applied at the following ratio,
In the present invention, it is effective to coat the chips with a solid content of 20% or more, preferably 30% or more, and preferably 30 to 100%.
%, it is possible to make a particle board that is flexible and has excellent bending resistance and rebound elasticity. Next, an example of a method for preparing an adhesive to be applied to the inner layer chip will be described. If necessary, a foaming agent is added to the latex adhesive (to which additives such as a vulcanizing agent are added), and a high-speed foaming stirrer is operated to cause foaming. It is effective to foam at a foaming ratio of 3 to 5 times. Examples of foaming agents include metal soaps such as potassium oleate and rosin acid. Adding an appropriate amount of a retarding gelling agent, such as a dispersion of sodium silicate, to this foam adhesive, preferably from 1 to 4 wt in terms of solid content, taking into consideration the application time and temperature.
% and stir. After addition and stirring, apply to the inner layer chips as soon as possible. For this application, a method similar to that used for applying latex adhesive to the surface chip is used. In the above case, it is effective to develop the gelling effect within a few minutes after application, and after gelling, the surface of the inner layer chip is covered with a stable coagulated rubber foam layer. Apply a gelling agent to the latex adhesive, such as salts such as ammonium chloride or ammonium phosphate, to the chip in advance, and then apply a foamed latex adhesive (not containing a delayed gelling agent). However, the same effect as above can be obtained. From the same point of view as mentioned above regarding the surface chips, the chips in the inner layer should also have a needle-like or flake-like shape, and be large enough to pass through a 10-mesh sieve but not pass through a 30-mesh sieve. It is preferable that the material is mainly composed of carefully selected sieve classification areas. The inner layer chip can be the same as the surface layer chip, as long as it is coarser than the surface layer chip. The inner layer chip has a length of 4 to 20 m/m and a thickness of
Relatively coarse chips of 0.4 to 0.8 m/m can be used. Preferably, the application of the foamed latex adhesive to the inner chip is carried out separately from the application of the latex adhesive to the surface chip. It is desirable that the coating devices are also different. The amount of foamed latex adhesive to be applied to the inner layer chip is preferably 20 to 80% by weight in terms of solid content based on the weight of the adhesive based on the weight of the inner layer chip. These chips coated with the adhesive home. In homing, for example, first, surface chips are uniformly spread on a metal plate to create the pine.
On top of this, chips for the inner layer (middle layer) are evenly sprinkled to form a mat for forming three layers. It may be a two-layered mat in which the surface layer mat and the inner layer mat are laminated, or it may be a mat with four or more layers. Next, these mats are inserted into a hot press and hot pressed. The heat and pressure conditions vary depending on the product thickness, etc., and cannot be generalized, but the heat and pressure temperature is 110 to 140℃, and the pressure is 1 to 15℃.
Preferably, it is Kg/cm ² . Although the cushioning properties are better when the pressure is relatively low, an appropriate pressure is applied in relation to the strength of the board. During hot pressing, the latex adhesive applied excessively to the surface layer of the chip penetrates into the interior of the chip through the cracks and fissures that exist in the chip due to heat and pressure, and the penetration of the rubber component softens the rigidity of the wood of the chip. Change to gender. The inner layer chip (middle layer) is a coarse chip, so
There is a void between the chips. In particular, when the pressing force is low, there will be many empty spaces. In this empty area, the solidified foam adhesive present on the surface of the inner chip remains in the empty area without collapsing the foam, and solidification is further promoted by heat to form a stable foamed rubber. This results in
An inner layer (intermediate layer) with high elasticity and cushioning properties can be formed. In addition, the bubbles in the area in contact with the chip are crushed by pressure and form an adhesive layer, creating a strong adhesive area. In the present invention, after hot pressing, heat vulcanization is preferably continued in order to further improve the durability and water resistance of the board and to improve the durability of good rubber elasticity. A method of continuing heating by hot pressure may be used, but in order to shorten the pressing time, it is preferable to perform heat treatment by placing the material in a heating chamber or passing it through a heating device. [Example] Next, the present invention will be explained in more detail with reference to Examples. Example 1 South Sea wood chips were applied to a grinder, and the wood chips obtained by grinding were dried, coarse pieces were removed in advance by an air classifier, and the pieces were further vibrated for the surface layer and the center layer. It was passed through a sieve to prepare acicular strips having the following two classification areas. The size of the surface layer strip is such that it removes ultrafine powder that passes through 30 meshes, and has a length of about 0.5 to 5 m/m and a thickness of about 0.2 to 0.7 m/m to pass through 20 meshes.
In addition, the size of the strip for the center layer is approximately 4 to 20 m/m in length after passing through 10 meshes, and approximately 0.4 to 1.4 m in thickness.
10 m of wood powder and wood grains are carefully selected by sieving and
Coarse pieces that did not pass through the mesh sieve were excluded. Latex adhesive (binder) used for surface layer
The main ingredient was carboxyl-modified SBR latex with a solid content of 67% and a monomer composition of about 72% phthalene and 28% styrene, and the following additives were added.

[Table] The coating amount was 75 parts of binder (approximately 50% solid content) per 100 parts of surface wood chips (dry weight). The adhesive (binder) used for the center layer was SBR latex with a monomer composition of approximately 72% phthalene and 28% styrene and a solid content of 65%, and the additives were in the following formulation.

[Table] Add and mix, then add sodium fluoride 50 1.5
Add and mix.
The coating amount was 65 parts of the binder per 100 parts of the central layer wood chips (dry weight). Approximately 3 minutes after application, a foamy film was formed as a gelled and solidified coating layer. Prepare equal amounts of these blend materials for the surface layer and the center layer, and perform 3-layer homing on the metal plate in the order of front-center-back.Three layers with equal amounts of layer composition between front and back versus center. The structure is made of pine. The required amount of mats with an average specific gravity of 0.65 Kg/cm ³ and a thickness of 4 m/m were hot-pressed under the following conditions. Thickness gauge (thickness bar) 3.75 m/m Heating temperature 120°C Pressure force 7 Kg/cm ² Pressing time 30 sec/m/m Furthermore, after hot pressing, heating was performed at 130° C. for about 30 minutes. The board obtained by the above method is a durable, resilient laminated board with a three-layer structure in which the front and back layers have high tensile and bending elastic strength, and the center layer has excellent elasticity and cushioning properties. , a particle board with anti-vibration effect was obtained. Example 2 Using carefully selected wood chips for the surface layer and center layer similar to those in Example 1, a mixed solution was prepared by adding 10% zinc white dispersion to the binder used for the surface layer in Example 1,
Apply this at a ratio of 80 parts to 100 parts of surface wood chips (dry weight). The binder used for the center layer is phthalene, approx.
%, SBR latex copolymerized with a monomer composition of about 27% styrene, whose solid content ratio is 75 parts, and natural rubber latex whose solid content ratio is 69%.
Using a mixed latex with 25 parts of 65% base as the base, additives were mixed as follows.

Add [Table] and mix.
Sodium fluoride 50 2
The material that can be added and further mixed is used as a binder. The amount of application is 100 parts of the wood strips in the center layer (dry weight) and 70 parts of the binder. Four minutes after application, it gelled and a solidified foam-like binder film layer was formed on the surface of the wood strip. The same three-layer structure as in Example 1 was used, and the surface layer: center layer: back layer was distributed into three layers in the ratio of 1:4:1, and the specific gravity was set to 0.60 Kg/cm ^{3 and} the thickness was set to 6 m/m. The required amount was hot-pressed under the following conditions. Thickness gauge (thickness bar): 6.00 m/m Heating temperature: 130°C Pressing force: 6 kg/cm ² Pressing time: 25 sec/m/m After hot pressing, heat vulcanization treatment was performed at 130° C. for about 30 minutes. The obtained board was an elastic particle board with particularly rich cushioning properties and a soft feel on its surface. Example 3 Selected wood chips for the surface and center layers were used in the same manner as in Example 1, in which 30 to 50% of white birch wood chips were mixed with rice wood chips and milled. The binder used was the following mixed latex main ingredient. SBR (butadiene approx. 70% styrene approx. 30% copolymer) / (solid content 67%) 65 parts NBR (butadiene approx. 86% acrylonitrile approx. 14%)
Copolymer)/(Solid content: 48%) 35 parts The additives were mixed as follows.

[Table] Apply the above binder at a ratio of 100 parts wood chips (dry weight) for the surface layer and 85 parts binder (solid content approximately 50%). The binder used for the center layer was the same as in Example 1, and the amount applied was 70 parts per 100 parts of the center layer wood chips (dry weight). 4 minutes after application, it gelled and formed on the surface of the wood chips. A solidified foam-like film layer was formed. Further, a three-layered mat having the same layer structure as in Example 1 was prepared, and the required amount of the mat was hot-pressed under the following conditions, with specific gravity set to an average of 0.70 Kg/cm ³ and thickness 3 m/m. Thickness gauge (thickness bar) 2.75m/m Heating temperature 125℃ Pressure force (1) 12Kg/cm ² × 1 minute Pressure tightening time (2) 6Kg/cm ² × 1 minute Approximately 30 minutes at 130℃ after hot pressing , heated and vulcanized. The 3m/m board obtained by the above method is
The result is an elastic particle board with viscoelastic properties that has a glossy surface with a varnish finish, and can be used as a surface material that functions as a material for curved surfaces with heat and sound insulation properties. [Effects of the Invention] According to the present invention, it is flexible and has excellent bending resistance,
Moreover, it was possible to provide a rubber-like particle board with good rebound elasticity and excellent durability. In addition, the laminated board obtained by the manufacturing method of the present invention combines the wood characteristics of the raw material, the rubbery flexibility due to the use of latex, and the layer structure characteristics due to the presence of elastic rubber foam in the center layer. It has excellent heat retention, sound absorption, and vibration isolation properties, and is suitable as a medium-specific gravity surface material for flooring, wall materials, and other residential construction materials.It is also a board with viscoelastic strength.
It can provide new functionality and diversification to furniture, furnishings, decorative materials, box materials, packaging materials, etc.
Furthermore, conventional particle board production equipment can be used as is, and this can be produced economically and inexpensively, especially when using an endless press method.

Claims (1)

[Claims] 1. In a method for manufacturing particle board using wood chips as raw material for particle board, prior to forming the surface layer of the board,
As an adhesive, monomers with conjugated double bonds are used in
Synthetic rubber latex obtained by copolymerization or homopolymerization using an emulsion polymerization method with a composition of 1% by weight or more
A mixed latex obtained by mixing one or more kinds of rubber latex or replacing a part of the synthetic rubber latex with natural rubber latex is used as the main material, and the main material is subjected to vulcanization necessary to vulcanize at least the rubber component in the latex. An adhesive (hereinafter referred to as a latex adhesive) containing one or more selected from the group consisting of a vulcanization accelerator, a vulcanization aid, and a vulcanization aid is used, and the latex adhesive is Applying an excessive coating amount to the chip in excess of the amount required for adhesion between the raw materials of the particle board, while prior to forming the inner layer of the board,
As the adhesive, a foamed latex adhesive is used, which is made by stirring and foaming a latex adhesive and adding and mixing a delayed gelling agent thereto. (hereinafter referred to as inner layer chips), and then
After laminating these chips into at least a two-layer structure using an inner layer chip coated with the foamed latex adhesive and one or more surface layer chips coated with the latex adhesive, the laminate is hot-pressed. A method for manufacturing a particle board made of wood material and having cushioning properties characterized by its elasticity.