JP2969473B2 - Method for manufacturing resin-impregnated wood - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a resin-impregnated wood, and more particularly, to a method for producing a wood / plastic composite material in which a resin solution is injected into wood and cured.

[Prior art] WPC (Wood Plastic Co.) in which vinyl monomer, unsaturated polyester, acrylic oligomer, etc. are injected into wood
Since the treatment material is injected with plastic, the wood becomes more transparent, becomes wet, and is in a state in which resin is injected. In other words, the texture of the wood is easily impaired.

Conventionally, a resin-treated wood having a material feeling by using a melamine resin or the like has been proposed, but there is a problem that crack resistance is poor.

Examples of patents that describe resin-treated wood having a material feel include JP-A-63-47102 and JP-A-63-98401.

[Problems to be Solved by the Invention] The present invention can improve the wet color by this WPC treatment, can perform a white wood-like resin treatment with high whiteness without impairing the material feeling, and can prevent the melamine resin from cracking. It is an object of the present invention to provide a technology capable of greatly improving the dimensional stability, improving the dimensional stability as compared with the case of the conventional WPC treatment, and keeping the hardness of the treated wood at the same level as the conventional example.

[Means for Solving the Problems] The present invention relates to a polyvalent resin having two or three hydroxyl groups in one molecule of 5 to 70% by weight based on the total weight of the reaction system when producing a melamine resin. Polyhydric alcohol-modified melamine resin obtained by blending and modifying alcohols in the system is impregnated and hardened in wood, or melamine resin 100
Impregnating and hardening wood with a polyhydric alcohol-melamine resin composition obtained by adding 5 to 70 parts by weight of a polyhydric alcohol having two or three hydroxyl groups in one molecule per part by weight. In the method for producing resin-impregnated wood characterized by the fact that, in particular, polyhydric alcohols, the average molecular weight 200
6000 polyethylene glycol.

Examples of the polyhydric alcohol having two or three hydroxyl groups in one molecule used in the present invention include dihydric alcohols (glycols) such as ethylene glycol and propylene glycol, and petriol (3-methylpentane-
Polyhydric alcohols (triol) such as glycerin and polyethylene glycol.

Polyethylene glycol has an average molecular weight of 200-6000
Are preferred. If the average molecular weight is less than 200, it is easy to obtain those having cracking resistance but lack of white wood tone,
On the other hand, if the average molecular weight exceeds 6000, the wood can be made white wood but impregnation into wood becomes difficult.

In the present invention, the above-mentioned polyhydric alcohols may be added to the reaction system in advance of the production of the melamine resin, and the polyhydric alcohol melamine resin modified with the polyhydric alcohol may be impregnated and hardened into wood. In the process,
Although the treatment may be performed using the resin composition obtained by adding the polyhydric alcohol to the melamine resin, as described in Examples below, in terms of improving crack resistance, the former is based on the former. Is preferred.

A melamine-based resin is generally a product mainly composed of methylolated melamine, which is produced by addition condensation of melamine and formalin. The present invention also includes a co-condensation resin co-condensed with urea or the like.

In addition, etherified melamine modified with butanol and propanol is also included.

In the present invention, 5 to 70% by weight, preferably 10 to 50% by weight of the total weight of the reaction system in the production of the melamine resin is added to the reaction system.
A polyhydric alcohol-modified melamine-based resin is obtained by blending the polyhydric alcohol by weight. As described above, the reaction system comprises, for example, a system of melamine, formalin, and a polyhydric alcohol.

By blending polyhydric alcohols, trimethylolmelamine reacts with polyhydric alcohols and is modified (etherified).

If the amount of the polyhydric alcohol is less than 5% by weight of the total 100% by weight, the crack resistance is insufficient, while if it exceeds 70% by weight, the curability of the melamine resin is insufficient.

In the present invention, as described above, the resin composition obtained by adding the polyhydric alcohol to the melamine resin may be used, and the polyhydric alcohol is added in an amount of 5 to 70 parts by weight based on 100 parts by weight of the melamine resin. Add by weight.

If the polyhydric alcohol is less than 5 parts by weight, the effect of improving the crack resistance is difficult, while if it exceeds 70 parts by weight, the curability upon curing is insufficient.

In the present invention, the impregnation hardening can be performed by a known method.

Various methods can be adopted, such as injecting a resin into a material under reduced pressure or pressure and heat-treating it at a high temperature, or impregnating the resin in a veneer, drying, laminating, and hot-pressing at a high temperature and a high pressure.

Wood referred to in the present invention includes various forms such as a resin injection treatment material and a cured laminated material.

In the present invention, a diluting solvent can be used as necessary, and a curing agent and other various additives can be used as necessary.

[Examples] Next, the present invention will be described based on examples.

Example 1. Various modified melamine resins were synthesized by adding 30% of ethylene glycol, petriol, and polyethylene glycol 600, and a resin solution was adjusted with water so that the resin component became 30%.

This resin solution was used to impregnate hemlock and oak veneers under a reduced pressure of 20 Torr.

Next, the resin-treated veneer was applied on the surface of the rawan plywood, on which an aqueous vinyl urethane adhesive was uniformly applied, and was pressed under heat and pressure at 120 ° C. and 8 kg / cm ² for 3 minutes. .

Crack resistance and hardness of the obtained veneers treated with various modified melamine resins were measured according to the following test methods.

(1) Crack resistance A cold repetition test based on JAS was performed.

The test method is as follows:
The process of leaving in a thermostat at −20 ° C. ± 3 ° C. for 2 hours is repeated twice.

(2) Hardness A Brinell hardness test based on JIS Z2117 was performed.

Hardness = P / 10 (kg / mm ² ) Here, P is the load (kg) when the press-fit depth becomes 1 / πmm.

 The results are shown in Tables 1 and 2.

The obtained veneers treated with various modified melamine resins retained their texture.

It can be seen that the crack resistance is greatly improved as compared with the melamine resin.

Crack resistance can be improved by adding polyethylene glycol 600 to melamine resin after synthesis, but it is not as effective as the modified one.

 Hardness was equivalent to melamine resin.

Example 2 A modified melamine resin containing 10% and 30% of polyethylene glycol 1500 was synthesized, and the resin solution was adjusted with water so that the resin content was 30%.

In the same manner as in Example 1 using this resin liquid, a resin-impregnated veneer of hemlock was obtained.

The obtained impregnated resin veneer was measured for color difference according to the following measurement method.

Measurement of color difference A color difference was measured based on JIS Z8722.

ΔE (Lab) = [(ΔL) ² + (Δa) ² + (Δb) ² )] ^1/2 where ΔE (Lab) = color difference by Lab system, ΔL, Δa, Δb
= Difference between the tone index L and the chroma index index ab of the two object colors in the Lab system The results are shown in Table 3.

The unsaturated polyester resin-treated veneer was in a state in which plastic was injected in a transparent wet color.

On the other hand, the veneer treated with PEG600 15% modified melamine resin retained the texture.

In addition, the PEG 1500 30% modified melamine resin had a whitening at the summer eyes portion, and had a clear white wood tone during the summer and winter.

Thus, the color tone of the veneer can be adjusted by adjusting the molecular weight of PEG.

[Effects of the Invention] As described above, according to the present invention, it is possible to improve the wet color by WPC treatment, to perform a white wood-like resin treatment with high whiteness without impairing the texture, and to improve the crack resistance of the melamine resin. The technology has been greatly improved, and it has been possible to provide a technology capable of improving the dimensional stability as compared with the case of the conventional PWC treatment and also keeping the hardness of the treated wood at the same level as the conventional example.

Claims (2)

(57) [Claims] 1. A method for preparing a melamine resin, wherein a polyhydric alcohol having two or three hydroxyl groups in one molecule is modified by mixing 5 to 70% by weight based on the total weight of the reaction system. A method for producing resin-impregnated wood, comprising impregnating and hardening the resulting polyhydric alcohol-modified melamine resin into wood. 2. A polyhydric alcohol having two or three hydroxyl groups in one molecule per 100 parts by weight of a melamine resin.
A method for producing a resin-impregnated wood, comprising impregnating and hardening a polyhydric alcohol-melamine-based resin composition obtained by adding up to 70 parts by weight into the wood.