JPS63118247A - Composite woody board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a composite wood board constructed by sequentially laminating adhesive and synthetic resin on a wood board, and more specifically relates to a composite wood structural material. For example, when used as a building material or interior decoration material, a synthetic resin layer laminated on a wooden board exhibits excellent surface gloss and surface hardness, and each layer has properties such as strong adhesion. Furthermore, the present invention relates to a composite wood board that exhibits an excellent cement surface finish when used for concrete formwork.

(Prior Art) Conventionally, as a composite wood board made of a synthetic resin and a wood board, there is a composite wood board in which an adhesive is applied to a wood board and a polyolefin sheet is adhered to the coated surface.

(Problems to be Solved by the Invention) However, the composite wood board has problems in use as a building material and interior decoration because the synthetic resin layer has poor surface gloss, surface hardness, and bone adhesion between each layer. .

Furthermore, when this is used for concrete formwork, there is a problem that the adhesion between each layer is poor, so it is easy to peel off, and the synthetic resin layer and cement are not easy to peel, so the finish of the concrete surface is poor. There was a point.

(Means for Solving the Problems) The present inventors have discovered that the synthetic resin layer has excellent surface gloss and surface hardness, has strong adhesion between each layer, and has a high releasability from cement. As a result of intensive research aimed at obtaining superior composite wood boards, we have developed a composite wood board in which adhesive and synthetic resin are sequentially laminated on wood boards.
As the synthetic resin, a mixture of a saponified ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVOH) having an ethylene content of 20 mol% or more and another thermoplastic resin (hereinafter abbreviated as TP) is used, and the synthetic resin The inventors have discovered that the above object can be achieved by adjusting the vinyl alcohol content of the mixture to 3 to 50% by weight, and have thus arrived at the present invention.

Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings. The attached drawings show a composite wood board to which the present invention is applied.
This is a cross-sectional view of a wooden board 4 coated with an adhesive 3 and coated with a synthetic resin mixture 2 of EV OH and another TP. Examples of the wood board 4 include boards made of various types of wood, plywood, particle board, fiberboard, and the like. Further, as the adhesive 3, adhesive polyolefin resin, polyurethane resin, polyisocyanate resin, polyvinyl acetate resin, ethylene-vinyl acetate copolymer, acrylic ester resin,
Synthetic resins and rubbers such as polyvinyl chloride resin, polyvinylidene chloride resin, urea resin, melamine resin, epoxy resin, natural rubber, chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc. In addition to adhesives, there are tackifiers such as petroleum resins, hydrogenated petroleum resins, terpene hydrocarbons, coumaron-indene resins, and natural product adhesives such as protein and polysaccharide. Although mixtures of the above may also be used, it is desirable to use adhesive polyolefin resins from the viewpoint of workability. Furthermore, the E V OII used in the synthetic resin mixture layer 2 may have an ethylene content of 20 mol% or more, and is not particularly limited to other materials. It is fine as long as it falls within the range of %. If the ethylene content is less than 20 mol%, the wet peel strength and wet surface hardness may decrease, which is not preferable. On the other hand, as the TP used for the synthetic resin mixture layer 2, polyethylene (hereinafter abbreviated as PE),
Polyolefin resins such as polypropylene (hereinafter abbreviated as PP), polybutene, ethylene-vinyl acetate copolymer (
(hereinafter abbreviated as EVA), edylene-acrylic acid copolymer,
Ethylene-based copolymers such as ethylene-ethyl acrylate copolymer, ethylene-α-olefin copolymer, ionomer, polyamide-based resin (hereinafter abbreviated as PA), polyvinyl chloride-based resin, polyvinylidene chloride-based resin, polyacrylonitrile resins, natural rubbers, chloroprene rubbers, nitrile rubbers, styrene-butadiene rubbers, etc. Mixtures of two or more of these rubbers can also be used, but in consideration of workability and economy, polyolefin resins or ethylene rubbers are used. Preferably, copolymers are used.

The peel strength of the composite wood board must be about 3 Kg725 mm or more in order to have peel resistance when processing the composite wood board and durability for long-term use. In addition, in order to maintain commercial value, it is desirable that the surface hardness be resistant to scratches, that is, it should have excellent scratch resistance, in other words, it should have high surface hardness. Surface hardness is expressed by Young's modulus, which indicates stiffness, and Young's modulus is 7000.
It is desirable that the surface gloss is 130% or more in terms of commercial value.Also, if the cement peel strength is 12Kg or less, an excellent cement surface finish will be obtained. If the weight exceeds 12 kg, the cement surface will become rough, so it is desirable that the weight is 12 kg or less.

The adhesive was applied using a roll coater, and the amount applied was about 3 to 5 g/m' in terms of solid content. If the coating amount is too small, such as less than about 0.5 g/m'', no adhesive effect will be achieved, whereas if it is too large, such as 10 g/m! or more, economical efficiency will be impaired.

In addition, the synthetic resin mixture is applied to the adhesive-applied surface using a T-die.
After extrusion coating with a thickness of 0.3 to 0.4 mm and bonding them together under heat, cold pressurization was performed. When the resin thickness is less than 0.01 mm, the thickness of the synthetic resin is thin, so unevenness and cracks on the surface of the wooden board are likely to be exposed on the product surface.
If the resin thickness exceeds 0.0 mm, it will impair economic efficiency, so the resin thickness should be set to 0.
The thickness is preferably in the range of 0.01 to 0.5 mm.

Examples of test results with varying vinyl alcohol contents are shown in Tables 1 to 3 below.

As shown in Table 1, when the vinyl alcohol content of the synthetic resin mixture was 3% by weight or more, the surface gloss, surface hardness, and peel strength were excellent, but when the vinyl alcohol content was 50% by weight or more, Since a decrease in peel strength is observed, the vinyl alcohol content of the synthetic resin mixture should be 3 to 5.
It was necessary that the content be in the range of 0% by weight.

Next, Table 2 shows the relationship between the type of EV OH and various physical properties.

As shown in Table 2, the ethylene content of EVOH is 20
When it was less than mol%, the physical properties after wetting were significantly reduced, but when it was 20 mol% or more, no decrease in physical properties was observed, so the ethylene content of EVOH must be 20 mol% or more. there were.

Next, Table 3 shows the relationship between the type of adhesive, the type of TP, and each physical property.

As shown in Table 3, various adhesives and various TPs whose vinyl alcohol content was within the range of the present invention had excellent physical properties.

In addition, a coloring agent, an ultraviolet absorber, a stabilizer, etc. can be appropriately added to the synthetic resin mixture as necessary.

(Effects of the Invention) As described above, the composite wood board of the present invention has excellent surface gloss and surface hardness, and each layer is strongly bonded, and has excellent finishing properties, especially on concrete surfaces. Therefore, it is suitable as a building material and an interior decoration material, and can also be used for concrete formwork, making a great contribution to the building materials industry.

(Example) The present invention will be explained in more detail with reference to Examples. However, parts indicate parts by weight.

Example 1: Adhesive polyolefin (emulsion-type acid anhydride-modified PE) was applied to a particle board with a thickness of 12 mm using a roll coater to a solid content of approximately 3 g/m'', then dried, and a synthetic resin was applied on top of it. Mixture (HDPE: l 00 parts,
EVOH (ethylene content: 32 mol%, 15 parts) was extrusion coated from a T-die at a resin temperature of 240° C. to a thickness of 0.3 mm, and cold-pressed. The obtained composite wood board is
Gloss of synthetic resin surface 150%, Young's modulus of synthetic resin layer 8
Peel strength is 3.5K g/25 at 400Kg/am”
mm, indicating good physical properties. When a storage box for small items was manufactured using the above composite wood board, there was no peeling of the composite wood board and the appearance was good.

Comparative Example-1 A composite wood board was manufactured in the same manner as in Example-1 except that EVOH was not used. The obtained composite wood board has a gloss level of 100 on the synthetic resin surface.
%, the Young's modulus of the synthetic resin layer was 4000 Kg/am2, and the peel strength was 0.8 Kg/25 mm. When a storage box for small items was manufactured using this composite wood board, the edges were peeled off during processing.

Example 2 Adhesive polyolefin (emulsion-type acid anhydride-modified PE) was applied to plywood with a thickness of 12 mm using a roll coater so that the solid content was approximately 3 g/e'', then dried, and a synthetic resin mixture was applied on top of it. (HDPE: 100 copies, EV OII:
(Ethylene content: 32 mol%, 15 parts) was applied by extrusion from a T4 die at a resin temperature of 240° C. to a thickness of OJmm, and cold-pressed. The obtained composite wood board has a gloss level of 150% on the synthetic resin surface and a Young's modulus of the synthetic resin layer of 8400 kg/
The peel strength at cm2 was 6.3 kg and 725 mm, and the cement peel strength was 10.5 kg, indicating good physical properties. When this composite wood board was used for concrete formwork, there were no problems even after repeated use 15 times, and the finish of the concrete surface was good.

Comparative Example 2 A composite wood board was manufactured in the same manner as in Example 2 except that EV OH was not used. The resulting composite wood board has the same gloss level as the synthetic resin surface! 00%, Young's modulus of synthetic resin layer = 1000 Kg/c
The peel strength is 1.2 Kg/cm" and the peel strength of cement is 15.3 Kg. When this composite wood board was used for concrete formwork, the composite wood board peeled off after the third use. It became impossible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a composite wood board showing an embodiment of the present invention. l...Composite wood board 2...Synthetic resin mixture layer 3...Adhesive layer 4...Wood board

Claims (1)

[Claims] 1. In a composite wood board in which an adhesive and a synthetic resin are sequentially laminated on a wood board, the synthetic resin has an ethylene content of 20
1. A composite wood board comprising a mixture of a saponified ethylene vinyl acetate copolymer of mol % or more and another thermoplastic resin, and characterized in that the vinyl alcohol content of the synthetic resin mixture is 3 to 50% by weight.