JPS63118248A - Laminated wood board for concrete formwork - Google Patents

Abstract

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

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a laminated wooden board formed by laminating a synthetic resin on a wooden board. When used as an interior decoration material, the synthetic resin layer laminated on the wooden board exhibits excellent surface gloss and surface hardness, and each layer has properties such as strong adhesion. The present invention relates to a laminated wood board that exhibits an excellent cement surface finish when used for a frame.

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

(Problems to be Solved by the Invention) However, the laminated 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 adhesion between each layer. .

Furthermore, when this is used for concrete formwork, the adhesion between each layer is poor, so it is easy to peel off, and the synthetic resin layer and cement have poor peelability, resulting in poor concrete finish. 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 corroded laminated wood boards, we found that in laminated wood boards in which synthetic resin is laminated on wood boards, ethylene-vinyl acetate with an ethylene content of 120 mol% or more is used as the synthetic resin. A mixture of a saponified polymer (hereinafter abbreviated as EVO I) and another thermoplastic resin (hereinafter abbreviated as TP) is used, and the vinyl alcohol content of the synthetic resin mixture is reduced to 3.
The present invention has been achieved by discovering that the above object can be achieved by setting the weight ratio to 50%.

Hereinafter, the present invention will be described in detail based on specific examples shown in the accompanying drawings. The attached drawings show a laminated wood board to which the present invention is applied.
This is a cross-sectional view of a wooden board 3 coated with a synthetic resin mixture 2 of EV OH and Ike's TP. Examples of the wood board 3 include boards made of various types of wood, plywood, particle board, fiberboard, and the like. Furthermore, the E V OI used in the synthetic resin mixture layer 2 may be 20 mol % or more of ethylene, and is not particularly limited. It is acceptable as long as the ethylene content is within the range of 50% by weight.If the ethylene content is less than 20% by mole, the peel strength when wet and the surface hardness when wet are lowered, which is undesirable.On the other hand, the synthetic resin mixture layer The TP used for 2 is polyethylene (hereinafter abbreviated as PE),
Polypropylene (hereinafter abbreviated as PP), polyolefin resins such as polybutene, ethylene-vinyl acetate copolymer (
(hereinafter abbreviated as EVA), edylene-acrylic acid copolymer,
Ethylene copolymers such as ethylene-acrylic acid copolymer, ethylene-α-olefin copolymer, ionomer, polyamide resin (hereinafter abbreviated as PA), polyvinyl chloride resin, polyvinylidene chloride resin, polyacrylonitrile rubber, natural rubber, chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc.Although mixtures of two or more of these can be used, considering workability and economy, polyolefin resin or It is preferable to use an ethylene copolymer.

The peel strength of the laminated wood board must be about 3 kg/25 mm or more in order to have peel resistance when processing the laminated 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, excellent scratch resistance, or in other words, high surface hardness. Surface hardness is expressed by Young's modulus, which indicates stiffness, and Young's modulus is 7000.
Kg/cI is preferably 11" or more. Furthermore, from the viewpoint of commercial value, it is desirable that the surface gloss is 130% or more. Also, if the cement peel strength is 12 Kg or less, excellent cement surface finish will be achieved. If the weight exceeds 12 kg, the cement surface will become rough, so it is desirable that the weight is 12 kg or less.

In addition, the synthetic resin mixture is applied to a wooden board using a T-die to form a 0.3
After extrusion coating with a thickness of ~0.4n+m and bonding them together under heat, they were cold-pressed. 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.On the other hand, when the resin thickness is less than 0.5 mm,
The resin thickness should be set to 0. O1
It is preferably in the range of ~0.5+nm.

Tables 1 to 3 below show examples of test results with varying vinyl alcohol content (m).

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 is 3 to 5.
It was necessary that the content be in the range of 0% by weight.

Next, the relationship between the type of E V OI-1 and various physical properties was investigated in the second
Shown in the table.

As shown in Table 2, the ethylene content of EVOI is 2
When the ethylene content of EV OH was less than 0 mol%, the physical properties after wetting were significantly reduced, but when it was 20 mol% or more, no decline in the physical properties was observed, so the ethylene content of EV OH was 20 mol%. This was all that was needed.

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

As shown in Table 3, 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 laminated 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 it 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 Synthetic resin mixture (H
DPE: 100 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 0.3n++++, and cold-pressed. The resulting laminated wood board has a synthetic resin surface with a gloss level of 150%.
The Young's modulus of the synthetic resin layer was 8400 Kg/am" and the peel strength was 3.1 Kg/25 mm, indicating good physical properties. When a storage box for small items was manufactured using the above laminated wood board, peeling of the laminated wood board was observed. The appearance was good and there was no blemish at all.

Comparative Example-1 A laminated wood board was manufactured in the same manner as in Example-1 except that EVO11 was not used. The obtained laminated wood board had a gloss level of 100% on the synthetic resin surface and a Young's modulus of the synthetic resin layer of 4000 Kg/cm.
The peel strength was 0.5 kg/25 ml11, and when a storage box for small items was manufactured using this laminated wood board, the edges peeled off during processing.

Example-2 Synthetic resin mixture (14Dr'E:
100 parts, EVOH: ethylene content 32 mol%, 15 parts) was melted from a T-die to a thickness of 0.3 m at a resin temperature of 240°C.
It was applied by extrusion so as to have a thickness of m, and was cold-pressed. The obtained laminated wood board had a gloss level of 150% on the synthetic resin surface, a Young's modulus of the synthetic resin layer of 8400 Kg/cm', and a peel strength of 11.2 Kg.
/ 25 mm, and the cement peel strength was 10.5 kg, indicating good physical properties. When this laminated wood board was used for concrete formwork, there were no problems and the finish of the concrete surface was good even after repeated use 15 times.

Comparative Example-2 A laminated wood board was manufactured in the same manner as in Example-2 except that EVO11 was not used. The obtained laminated wood board has a gloss level of 100% on the synthetic resin surface and a Young's modulus of the synthetic resin layer of 4000 kg/
Cm" has a peel strength of 0.8 kg/25 mm, and a cement peel strength of 15.3 kg. When this laminated wood board was used for concrete formwork, the laminated wood board peeled off after the third use and was no longer used. It became impossible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a laminated wood board showing an embodiment of the present invention. l...Laminated wood board 2...Synthetic resin mixture layer 3...Wood board Applicant Okura Kogyo Co., Ltd. Agent Patent attorney Fu Ohama (Is/: Laminate Wooden board 2 Two synthetic resin mixture layers 3: Wooden board

Claims (1)

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