JPH03288604A - modified wood - Google Patents

Abstract

PURPOSE:To obtain modified lumber having uniform durability, dimensional stability and beautiful appearance as a whole, by a method wherein a ligneous material is cured by impregnating the same with an aqueous solution consisting essentially of phenolic resin and amine acetate. CONSTITUTION:Modified lumber is formed by curing the lumber by impregnating the lumber with an aqueous solution consisting essentially of phenolic resin and amine acetate. Trans-1, 2-chlorohexane diamine tetraacetate, diethylenetriamine pentacetate, ethylene diamine biacetate, ethylene diamine tetraacetate, 3, 6-dioxane-1, 8-octane diamine tetraacetate, N-(2-hydroxyl ether) ethylene diamine triacetate, N-(2-hydroxyl ether) imino biacetate and triethylene tetramine hexaacetate are available as amine acetate mixed with phenolic resin. A compounding ratio of the amine acetate to the phenolic resin (solid content) is preferable to be within 0.1-20% and density of mixed resin aqueous solution is selected within 5-30%.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention provides a material with excellent dimensional stability, durability, and appearance that is suitable for use as building exterior materials, bathroom wall materials, and other construction materials. It concerns modified wood.

(Prior art) Modified wood, which is obtained by injecting and curing a synthetic resin liquid into wood, has been widely known.In particular, for the purpose of improving dimensional stability and durability, it has been widely known that wood has been injected and cured with a phenolic resin. Modified wood is used for construction materials, furniture materials, etc., and its properties are effectively demonstrated.

(Problem to be solved by the invention) However, natural wood materials have variations in the pores in their cell walls and other impurities that impede the penetration of the treatment solution. Although it has a moderate permeability into wood materials, its permeability decreases depending on the liquid quality of the phenol resin, storage conditions, etc., and it becomes unable to penetrate uniformly into the wood materials. It was not possible to obtain modified wood having physical properties such as overall durability and dimensional stability.

Further, this resin-infused wood material has a problem in that the surface becomes darkened by the phenol resin, which significantly impairs the appearance and has poor cosmetic properties.

The main cause of this deterioration is that the phenolic resin changes into a colored structure due to ultraviolet rays, oxygen, etc. during the injection of the phenolic resin aqueous solution into the wood material, during the heat curing process, or during the use of the resin-infused wood material. It seems that there is.

The present invention was made in view of such conventional problems, and
The object of the present invention is to provide modified wood that has uniform durability and dimensional stability as a whole and has a beautiful appearance.

(Another Means to Solve the Problems) In order to achieve the above object, the modified wood of the present invention is characterized in that it is made by impregnating and curing a wood material with an aqueous solution containing phenolic resin and amine acetate as essential components. That is.

(Function) A phenol resin aqueous solution to which amine acetates are added prevents coagulation and precipitation of the phenol resin, and increases the swelling of the wood material, resulting in a large amount of impurities that impede the penetration of the aqueous solution. Even if it is a wood material, or even a wood material with variations in internal void density, when injected, it penetrates evenly and well into the village, and the overall dimensional stability and durability are maintained. Modified wood that exhibits properties such as elasticity can be obtained.

In addition, the PH of the phenol resin in the aqueous solution changes to neutrality due to the amine acetate, making it difficult for the phenol resin itself to darken, preventing darkening.
Even if exposed outdoors, the coloring ingredients will not change in quality! This reduces darkening (staining) and maintains a beautiful appearance for a long period of time.

(Example) Next, an example of the present invention will be described in detail. Modified wood is formed by impregnating and curing an aqueous solution containing phenolic resin and acetic acid amines as essential components. be.

Wood materials into which the mixed resin liquid described above is injected include:
Thick lumber products such as square lumber, board material, and hollow lumber, as well as laminated lumber, are used, but even thin plates such as veneers can of course be treated with injection treatment.

In addition, the synthetic resin to be injected is a phenolic resin that penetrates into wood cell walls and forms an insoluble and infusible substance in the cell wall structure, and this resin can be used alone or mixed with formalin resin, or It may also be a co-condensed resin liquid.

When producing the modified wood described in Section 2, if amine acetate is mixed with the above phenolic resin and this mixed resin liquid is injected into the wood material, it will not be affected by differences in the wood species or density variations of the wood material. This is preferable because the mixed resin liquid penetrates deeply and uniformly into the cell walls of the woody moss without causing any damage, and it also becomes difficult to be washed away outside the plant in the solvent volatilization process described later, improving the syncytial rate.

This is thought to be because the amine acetate increases the swelling of the wood material, making it easier for the mixed resin solution to penetrate into the wood material.

In addition, the amine acetates act directly on the phenolic resin liquid to prevent it from discoloring (deepening) and agglomerating, and together with the good permeability of the mixed resin liquid into the wood material, it improves the appearance. Beautiful modified wood can be easily obtained.

Acetate amines to be mixed with the phenol resin include trans-1,2-cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetriacetic acid, ethylenediaminetetraacetic acid, 3,6 dioxer 1,8-octanediaminetetraacetic acid, N(2 -hydroxyethyl)ethylenediaminetriacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, triethylenetetraminehexaacetic acid, and the like.

The blending ratio of the amine acetate is preferably 0.1 to 20% based on 1 of the phenol resin (solid content), and the concentration of the aqueous solution of these mixed resins is selected between 5 and 30%.

Next, to describe a specific method for manufacturing the above-mentioned modified wood, first, the above-mentioned resin solution containing phenolic resin and acetic acid amines as essential components is injected into the wood material to impregnate it, and then this resin solution impregnation treatment is performed. A single piece of wood material, or in the case of a plurality of thin plates, are stacked and sandwiched between heating plates whose temperature can be adjusted.

At this time, in order to improve productivity, it is preferable to process the wood materials sandwiched between heating plates by stacking them in multiple stages.

In addition, it is desirable to provide a step of removing the solvent before heat curing with a heating plate in order to perform a homogeneous curing reaction, and as such a solvent removal means, vacuum drying, high frequency drying, and hot air drying are used in combination as appropriate.

If such a solvent removal process is performed before heating and curing the wood material, the initial condensation reaction of the injected mixed resin liquid will proceed as dehydration from the wood material progresses, and resin components will be deposited in the micropores of the wood material. remains and is difficult to flow out.

Next, we move on to the heat curing process of the resin-infused wood material.
In this step, the temperature of the heating plates sandwiching the wood material is raised to 100 to 160'C, and the injected resin is reacted. At this time, since amine acetate is contained, thermal discoloration of the phenol resin can be suppressed.

In this heat curing process, high-temperature heat treatment is performed with forced exhaust air, and the forced exhaust gas removes volatile components such as formalin and residual moisture remaining in the wood.
The moisture generated by the condensation reaction of the resin is evaporated and reduced, and the injected mixed resin is cured by high temperature heating.

The curing temperature of the injected resin is set within the above temperature range depending on the type of resin to be injected.

As described above, the reaction of the resin is completed by the step of evaporating the water in the wood material to remove volatile components and the step of heating the wood material to raise its temperature.

Note that hot air or a hot press may be used successively after the vacuum is released at the final heat curing temperature (100° C. or higher), the drying step, and the curing step.

Next, specific examples and comparative examples of the present invention will be shown.

(Example) Thickness 1.0+++m, width 100mm, length 200m
A mixed resin aqueous solution consisting of 10% phenolic resin (solid content 50%) and 0.1% ethylenediaminetetraacetic acid was injected into three types of veneers made of Japanese cedar, birch, and maple using the normal vacuum pressure injection method. After drying under reduced pressure, each modified wood veneer was obtained by heating and curing at 160°C for 30 minutes.

All of the modified wood veneers thus obtained had no darkening or dullness on their surface layers, and had a high yield without requiring sanding to remove contamination.

(Comparative example) 3 made of cedar, birch, and maple with the same dimensions as above
Type of veneer with 10% phenolic resin (solid content 50%)
The sample was injected under the same conditions as in the above example and cured by heating.

All of the modified wood veneers thus obtained had darkened surface layers, and significant contamination was observed.

Next, the physical properties of the modified wood veneers obtained in the above Examples and Comparative Examples will be shown.

In the above table, the dimensional stability is indicated by the anti-shrinkage ratio (ASE) determined by a water absorption test under reduced pressure.

As is clear from this table, the modified wood veneers in Examples of the present invention have excellent dimensional stability and a beautiful appearance with no darkening.

(Effects) As described above, the modified wood according to the present invention is obtained by impregnating and curing a wood material with an aqueous solution containing phenolic resin and amine acetate as essential components. When a mixed resin solution with amine acetates is injected into wood materials, the amine acetates can prevent the phenol resin from coagulating and settling, and at the same time increase the swelling of the wood material and prevent impurities from penetrating the treatment solution. Even if the wood is made of wood with a lot of porosity or has uneven internal void density, the resin liquid can be penetrated evenly and well into the wood, and the overall size is similar. Modified wood with performance such as stability and durability can be provided.

In addition, the amine acetate prevents darkening caused by the phenolic resin itself, so the modified wood does not darken.Furthermore, even when exposed outdoors, the coloring components are less likely to change in quality, resulting in less darkening. , which can maintain a beautiful appearance for a long period of time.

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Claims (1)

[Claims] 1. A modified wood characterized by impregnating and curing a wood material with an aqueous solution containing phenolic resin and amine acetate as essential components.