JPS62299303A - Preparation of particle board - Google Patents

Abstract

PURPOSE:To impact excellent flexing resistance and impact resilience and to enhance a heat retaining property and a sound-proof property, by constituting a particle board of a skin layer consisting of wood chips excessively coated with a specific latex adhesive and an inner layer containing coarse wood chips coated with a specific foamed latex adhesive. CONSTITUTION:A latex type adhesive comprising synthetic rubber latex having a conjugated double bond is used and applied to wood chips in an excessive amount exceeding coating amount necessary for adhering wood chips to obtain a skin layer containing chips of which the woody tissue is made flexible and having a rubber elasticity showing a repulsion force. This skin layer part is used on front and back sides and an inner layer is interposed as an intermediate layer to constitute a three- layered structure. In the inner layer, a foaming agent is used in the same latex adhesive and the resulting mixture is foamed under stirring at a high temp. and a retarding gelling agent is added. The chips of the inner layer part are coarser than those of the skin layer and the gap parts between chips are filled with an elastic rubber foam composition. By this method, such a particle board can be obtained that has a good feeling and a good cushioning property, an excellent heat insulating property, a sound- proof property and a vibration damping property and is suitable for a house building material.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of manufacturing particle board, and in particular,
Good cushioning properties, excellent heat retention, soundproofing, and vibrationproofing effects.
This invention relates to a cushion port (mat) with a three-layer structure that has excellent performance as flooring material for housing construction materials.

(Conventional technology 1) Particle board, which is obtained by molding and hot pressing wood chips with adhesive, has the characteristics of high utilization of wood resources and the ability to obtain uniform long products. It is widely used in automobile interior materials, etc.

Conventionally, resin-based adhesives such as urea-based, phenol-based, melamine-based, and incyanate-based resins have been used as adhesives for manufacturing particle boards (Japanese Unexamined Patent Publication No. 57-207058). ), hardeners may also be added to accelerate curing, and when it comes to adhesive application, the adhesive must be applied to the entire surface of the piece and be uniform in a minimally thick layer. One of the requirements for coating was "Wood Industry Handbook" published by Maruzen Co., Ltd., June 30, 1981, pp. 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 that is flexible, has excellent bending resistance, and has a rubber-like particle board that has anti-resilience properties and has excellent durability. The purpose is to provide something.

The present invention also has wood-like characteristics and rubber-like flexibility,
The above-mentioned and other objects and novel features of the present invention, such as heat retention, soundproofing (sound absorption), and vibrationproofing properties, will become clear from the description in this specification.

[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 an adhesive having a conjugated double bond is used as an adhesive prior to forming the surface layer of the board. Obtained by mixing one or more types of synthetic rubber latex obtained by copolymerization or homopolymerization using an emulsion polymerization method, or by replacing a part of the synthetic rubber latex with natural rubber latex, with the main composition being Natsuma. Using an adhesive (tex adhesive) made of a mixed latex as a main ingredient and adding at least an additive necessary for vulcanizing the rubber component in the latex to the main ingredient,
and the latex adhesive is applied to the chips in excess of the amount required for adhesion between particle board raw materials (chips) such as wood chips, while forming the inner layer of the board. As an adhesive prior to
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, and then a delayed gelling agent is added and mixed. A foamed latex adhesive was applied to an inner layer chip that contained more coarse chips than the surface layer chip, and then the inner layer chip coated with the foamed latex adhesive and the latex adhesive were applied. A laminated particle board made of wood material with cushioning properties, characterized in that it is made by laminating at least two layers of chips using surface chips on one or a tool, and then hot pressing the laminate. It consists in the manufacturing method.

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 chips, which are the raw material for particle board, are used. On the other hand, by applying an excessive amount of adhesive in excess of the amount required to bond the chips, the necessary adhesive layer is formed between the chips, and the excess adhesive is deposited inside the chips. A particle board surface layer with rubber elasticity that is penetrated by the heat-pressing process, softens the chip wood, and has resilience is obtained, and is also highly durable due to the vulcanization treatment of the latex adhesive. , a particle board surface layer similar to that of a rubber product can be obtained. The particle board according to the present invention is of a laminated type, and the surface layer portion can be used to form a laminated mat-like product. It has a three-layer structure in which 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 (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 chip 2 chips coated with adhesive are hominated to form a three-layered mat, which is then hot-pressed using a press.

Since the inner layer (intermediate layer) chips are coarser than the surface layer chips, 1.
Filled with elastic rubber foam. The particle board thus obtained has cushioning properties with a good feel, 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.

Chips used in the present invention (particle board raw material)
Various types of materials used for general particle boards can be used. The raw material of particle board is generally.

In the present invention, it is preferable to use wood chips obtained by cutting or crushing wood as a raw material, and some of the wood chips are replaced with particulate or fibrous inorganic substances. It is preferable that the chips are dried to a moisture content of 10% or less.

It is preferable that the chips are matched in shape and size, and that the applied latex adhesive is evenly infiltrated and evenly softened during hot pressing, and that a homogeneous matrix layer is formed by stable forming. Preferably, the material has a strong elastic surface.

From these points of view, the surface layer chips are acicular or flaky 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 may have a length of 0.5 to 5 m/m and a thickness of 0.1 to 0.7 m/m.

The latex adhesive used in the present invention has synthetic rubber latex as its main ingredient.

Examples of the synthetic rubber latex include butadiene rubber,
Examples include imprene rubber, chloroprene rubber, styrene butadiene rubber (SBR), and acrylonitrile butadiene rubber latex.

Synthetic rubber latex has a composition of 70% or more of monomers having 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. The properties of the latex and the characteristics of the rubber components differ 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 anti-blow elasticity, and has improved properties such as durability, water resistance, heat resistance, and oil resistance, as well as workability in use and price. It is preferable to use a mixture of two or more types of rubber latex.

A part 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 to this 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 vulcanizing effect, and provide durability to the board, a vulcanizing agent with a vulcanizing effect must be added to the latex. A commercially available sulfur powder for rubber vulcanization can be used as the vulcanizing agent that is preferably dispersed therein. 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 is
It acts as a vulcanizing agent for BR, nitrile rubber, chloroprene rubber latex, etc.

Various types of vulcanization accelerators can be used; for example, thiazole-based Ichisaka products with the product symbol MZ, or dithiocarbamate-based Ichisaka products with product symbols EZ and Px are used. can do.

In the present invention, it is preferable to use an antiaging agent to prevent aging of the latex, and specific examples thereof include phenolic antiaging 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 manufacturing a latex adhesive and a preferred range of the amount of the additive used will be shown.

The order of manufacture is to put the required latex into a mixer. In case of mixed latex, 0.0% for latex.
Add 5-1% potassium oleate and mix with stirring. Add each additive while operating the mixer.
2%, vulcanization accelerator 1-5%, vulcanizing agent (sulfur) 2-3%,
A vulcanization aid (zinc white) is added in the order of 2 to 6% and mixed with stirring. (The percentage value is the usage ratio for latex (w)
t).

By completing stirring and mixing, a latex adhesive is obtained.

In order to make the particle board flame retardant,
It is good to add 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.

To apply latex adhesive to the surface layer part 2, for example, put the chip in a coating machine called a blender and apply it by spraying.Generally, in the particle board manufacturing method, the amount of application is based on the weight of the chip. Although the adhesive is applied at a solid content of 15% (wt) or less, in the present invention, the solid content of the adhesive is 2% (wt) or less.
It is effective to apply 0% or more, preferably 30% or more.
When applying 0 to 100%, the particle board can be made flexible and has excellent bending resistance and resilience.

Next, an example of a method for preparing an adhesive to be applied to the inner layer chip will be described. If necessary, add a foaming agent to the above latex adhesive (additives such as a vulcanizing agent are added), and operate a high-speed foaming stirrer to foam the adhesive to a foaming ratio of 3 to 5 times. It is effective to encourage them.

Examples of foaming agents include metal compounds such as potassium oleate and rosin acid.

To this foamed adhesive, an appropriate amount of a retardant gelling agent, such as a dispersion of sodium silicofluoride, preferably 1 to 4 tX in terms of solid content, is added and stirred, taking into account the application time and temperature.

After addition and stirring, apply to the inner layer chip as soon as possible. The coating method is the same as the method for coating the latex adhesive on the first surface chip.

In the above case, it is effective to develop the gelling effect within a few minutes after application, and after gelling.

The inner chip surface 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 foaming 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 layer chips, the inner layer chips should also have a needle-like or flake-like shape and a size that will not pass through a 10-mesh sieve but a 30-mesh sieve. It is preferable that the material is mainly composed of carefully selected sieving 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 4~2h/false, and a thickness of 0°4~0
．． A relatively coarse tip of 8 m/ltr can be used.

The application of foamed latex adhesive to this inner layer chip is
It is preferable to perform this separately from the application of the latex adhesive to the surface layer 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 are coated with the adhesive.

Home.

Homing may be carried out, for example, by first uniformly scattering surface layer chips on a metal plate to form a mat, and then forming a mat with four or more layers of inner layer (middle layer) chips on top of this.

These mats are then 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 110-140℃, and the pressing force is 1-15 kg/
crn' is preferred.

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 inside 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 reduces the rigidity of the wood of the chip. change into flexibility.

Since the inner layer chips (intermediate layer) are coarse chips, there are gaps between the chips. In particular, when the applied pressure is low, there will be many voids. In this void, the solidified foam adhesive present on the surface of the inner layer chip does not collapse, but remains in the foam state, and is further accelerated by heat to solidify into a stable foamed rubber. As a result, the inner layer (middle layer) is rich in elasticity and cushioning properties.
can be formed.

In addition, the bubbles in the area where the chip contacts are crushed by pressure and become an adhesive layer, resulting in a strong adhesive area.

In the present invention, in order to further improve the durability and water resistance of the board and to improve the durability of good rubber elasticity, it is preferable to continue heating and vulcanizing after hot pressing. However, 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 Korean wood chips were applied to a grinder, and after drying the resulting wood chips, coarse pieces were removed using an air classifier in advance, and these were further divided into surface and center layers. Acicular strips having the following two classification ranges were prepared by passing through a vibrating sieve.

The size of the surface layer strip is such that it removes ultrafine powder that passes through 30 meshes, and the length that passes through 20 meshes is approximately 0.5~
5 m/s and a thickness of approximately 0.2 to 0.7 m/m, and the size of the strip for the center layer is approximately 4 to 20 m/m in length after passing through 10 meshes, and a thickness of approximately 0. 0.4 to 1.4+w/m was sieved to remove the wood flour and wood grains, as well as the crude juice that did not pass through a 10-mesh sieve.

The latex adhesive (binder) used for the surface layer has a monomer composition of about 72% butadiene and about 28% styrene, and its main ingredient is carboxyl-modified SBR latex with a solid content of 67%, and the additives are as follows. It was a combination.

Drug name Solid content Amount (%)
(Part) (vl:, "Me ■ Closed SBR latex (main agent) 67 100.0 Anti-aging agent S P
60 1.0 Sulfur 50
2゜Vulcanization accelerator MZ 50, 1.5 Zinc Flower 50
2.0 The amount of application is 10 pieces of wood chips for surface layer (dry amount)
0 parts to 75 parts of binder (approximately 50% as solid content)
was applied.

The adhesive (binder) used for the center layer is butadiene, approx.
6% solids with a monomer composition of approximately 24% styrene.
The main ingredient was SBR latex, and the additives were in the following formulation.

Drug name Solid content Amount (%)
(Part) SBR latex 65 1aO.

Anti-aging agent S P 60 1゜Sulfur
yellow 50 2
5 Vulcanization accelerator MZ 50 1°//// EZ 50 1° After the above mixing is completed, potassium oleate 0.7 is added and stirred at high speed to cause foaming.

When the foaming ratio increases to about 3 times, Zinc Flower 50
3 was added and mixed, and 50 1.5 of sodium silifluoride was further added and mixed.

The amount of coating 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 form three layers on a metal plate in the order of front, center and back to create a three-layer structure with an equal amount of layer composition between the front and back versus the center. Made matte.

The required amount of mats having an average specific gravity of 0.65 kg/cm'' and a thickness of 4 m/a were hot-pressed under the following conditions.

Thickness gauge (thickness bar) 3.75+s/■Heating temperature 120
Partial pressure
7 kg/c pressure tightening time
30 sec/m/ra (r sea) Further, the board obtained by heating at 130° C. for about 30 minutes after hot pressing was a particle board with a surface layer and a back layer having a tensile effect.

Example 2 Using refined wood pieces for the surface layer and center layer of Examples 1 and 144, a mixed solution was prepared by adding 10% zinc white dispersion to the binder used for the surface layer of Example 1, This is applied at a ratio of 80 parts to 100 parts of surface wood chips (dry amount).

The binder used for the center layer is SDR latex copolymerized with a monomer composition of about 73% butadiene and about 27% styrene, with a solid content ratio of 69%, and 75 parts of a base material made of natural rubber latex, whose solid content ratio is 69%. is 65% of the main ingredient.
Using the mixed latex with 5 parts as the main ingredient, the additives were mixed as follows.

Drug name Solid content Amount (%)
(Part) SBI<-7Te1. , Kusu
6 ぢ 100 Anti-aging Agent S P
60 1.5 Sulfur 5
0 2 vulcanization accelerator MZ 50 1 tt tt //EZ 50 1 oleic acid soap -l was added and the foaming ratio became about 4 times.

Zinc flower 50
Add 4 and mix, and mix.
2φ is added and mixed into Z as a binder. The coating amount is 70 parts of the binder per 100 parts of the central layer wood chips (dry weight). 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 mat as in Example 1 was placed on one table,
The required amount of mat with a specific gravity of 0.80 kg/am' and a thickness of 8+s/m was hot-pressed under the following conditions.

Thickness gauge (thickness bar) 6. OOm/m heating temperature 1
30 parts pressure
After hot pressing at a pressure of 6 kg/crn' for a time of 25 sec/m/m, heat vulcanization treatment was performed at 130° C. for about 30 minutes.

The obtained board was an elastic particle board with rich cushioning properties, especially the surface of the board had a chestnut feel.

The selected wood strips for the surface layer and center layer were used, and the following mixed latex base material was used as the binder for the first surface layer.

SBR (copolymer of approx. 70% butadiene and approx. 30% styrene) / (solid content 67%) 65 parts NBR (copolymer of approx. 86% butadiene and approx. 14% acrylonitrile) /
(Solid content: 48%) 35 parts and added chemicals were mixed as shown below.

Drug name Solid content Amount (%)
(Parts) Mixed latex 60 /ρbe Anti-aging agent SP 60 1゜Sulfur 50
2゜Vulcanization accelerator MZ 50 1 tt tt //EZ 50 1.5
Lead Flower 50 2゜Tie 100 parts of the above binder to wood strips for the surface layer (dry weight).
Mixture 8
Apply at a ratio of 5 parts (approximately 50% solid content).

The binder used for the center layer was the same as in Example 1, and a solidified foam-like film layer was formed on the surface of the piece.

Furthermore, a three-layer structure mat having the same layer structure as in Example 1 was prepared, and the required amount of the mat, which had a specific gravity of 0.70 kg/cm on average and a thickness of 3 m/m, was hot-pressed using the following ratio.

Thickness gauge (thickness bar) 2.75 m/m
Heating temperature: 125℃ Pressure force
(1) 12kg/crn' X l Separation clamping time (2) 6kg/cnf X l
After heating and pressing, the pieces were heated and vulcanized at 130° C. for about 30 minutes.

The 3g+/m board obtained by the above method is as follows.

The result is an elastic particle board with viscoelasticity that has a glossy surface with a varnish finish, and can be used as a surface material that has the function of a curved surface material with heat and sound insulation properties.

[Effects of the Invention] According to the present invention, it was possible to provide a rubber-like particle board that is flexible, has excellent bending resistance, has good anti-shock elasticity, and has excellent durability.

Moreover, the laminated board obtained by the manufacturing method of the present invention is
It combines the wood characteristics of the raw material, rubber flexibility due to the use of latex, and layer structure characteristics such as the presence of elastic rubber foam in the center layer, and has excellent heat retention, sound absorption, and vibration damping properties, and has a medium specific gravity. As a material, it is suitable for housing construction materials such as flooring and wall materials, and as a port with viscoelastic strength, it is useful for new functionality and variety in 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.

Patent applicant: Oshika Shinko Co., Ltd. Takehara Industries Co., Ltd.

Claims (1)

[Claims] 1. In a method for manufacturing a particle board made of wood material, prior to forming the surface layer of the board, an adhesive is prepared by emulsion polymerization using a monomer having a conjugated double bond as the main composition. A mixed latex obtained by mixing one or more types of synthetic rubber latex obtained by copolymerization or homopolymerization or by replacing a part of the synthetic rubber latex with natural rubber latex is used as the main material, and the main material contains at least the above-mentioned latex. An adhesive (hereinafter referred to as "latex adhesive") made by adding the necessary additives to vulcanize the rubber component inside is used, and the latex adhesive is mixed with particle board raw materials such as wood chips (hereinafter referred to as "chips"). The latex adhesive is applied to the chip in excess of the amount required for adhesion between the boards, and the latex adhesive is stirred and foamed as an adhesive prior to forming the inner layer of the board. A foamed latex adhesive prepared by adding and mixing a retardant gelling agent therein is used, and the foamed latex adhesive contains many coarse chips compared to the chips (hereinafter referred to as surface chips). The foamed latex adhesive is applied to a chip (hereinafter referred to as an inner chip), and then, using the inner chip coated with the foamed latex adhesive and one or more surface chips coated with the latex adhesive, these chips are A method for producing a particle board made of a wood material and having cushioning properties, which comprises laminating at least a two-layer structure and then hot-pressing the laminate. 2. The manufacturing method according to claim 1, wherein the chips are wood chips obtained by cutting or crushing wood. 3. The surface layer chips are large enough to pass through a 30 mesh sieve but cannot pass through a 60 mesh sieve, and the inner layer chips are large enough to pass through a 60 mesh sieve.
The manufacturing method according to claim 1, wherein the manufacturing method has a size that allows it to pass through a 0 mesh sieve but not a 30 mesh sieve. 4. The amount of latex adhesive used is from 30% to 100% by weight based on the solid content of the adhesive based on the weight of the chip in the surface layer, and the amount of foamed latex adhesive used is less than the weight of the chip in the inner layer. The manufacturing method according to claim 1, wherein the solid content of the adhesive is 20% or more and 80% or less by weight. 5. The manufacturing method according to claim 1, wherein the retarded gelling agent is sodium silicofluoride. 6. When stirring and foaming the latex adhesive, a foaming agent,
The manufacturing method according to claim 1, wherein a thickener and/or a filler are added to cause foaming. 7. Claim 1, wherein the synthetic rubber latex has a composition of 70% or more of monomers having conjugated double bonds.
Manufacturing method described in section. 8. The manufacturing method according to claim 1, wherein the laminated particle board is a mat-like material having a three-layer structure, with an inner layer serving as an intermediate layer and surface portions laminated on both sides. 9. Claim 1, wherein the latex adhesive contains one or more additives selected from the group consisting of a vulcanizing agent, a vulcanization accelerator, and a vulcanization aid. manufacturing method. 10. The latex adhesive is formed by adding one or more additives selected from the group consisting of anti-aging agents, stabilizers, flame retardants, preservatives, waterproofing agents, and termiticides. A manufacturing method according to claim 1. 11. In the manufacturing method according to claim 1,
Claim 1: During hot pressing, the heating operation is continued to complete the vulcanization of the rubber component in the latex adhesive.
Manufacturing method described in section. 12. In the manufacturing method according to claim 1,
The manufacturing method according to claim 1, wherein a finishing operation is performed after hot pressing. 13. The manufacturing method according to claim 1, wherein the chips are made by replacing a part of wood chips with a particulate or fibrous inorganic substance.