JPH01174404A - Modified wood - Google Patents

Abstract

PURPOSE:To contrive to improve the durability, hardness and toughness of wood by a method wherein the active group such as hydroxyl group and the like in wood component is chemically modified by epoxidized higher fatty ester and, at the same time, said epoxy and novolak resin are polymerized on each other and cured in the voids in the wood. CONSTITUTION:Wood is impregnated, for example, under reduced pressure, with epoxidized higher fatty ester, which is internal olefin epoxide and consists of impregnating liquid produced by reacting epoxidized linseed oil with p-t-octyl phenol and formaline under acid conditions. Next, by heat-treating the resultant wood impregnated with the impregnating liquid for 2 hours at about 140 deg.C, the active group such as the hydroxyl group and the like in wood component is chemically modified by epoxidized higher fatty ester and, in succession, the epoxidized higher fatty ester and novolak resin are polymerized on each other and cured in the voids in the wood, resulting in imparting hardness and toughness to the wood.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention improves the aesthetic properties and other properties of wood materials by chemically treating the wood materials and at the same time filling and curing the wood voids with a polymer compound. It relates to modified wood that has improved durability, hardness, toughness, etc. without impairing it.

[Conventional technology and its problems]

Methods for combining wood materials and synthetic resins can be roughly divided into methods in which polymerizable substances are filled into the voids of wood materials (so-called WP).
C) and functional groups such as hydroxyl groups in wood components are reacted with oxides and acid anhydrides to form ethers.
There is a method of esterification called chemically modified wood.

There are various types of polymerizable substances and chemical modifiers, and research on epoxy compounds having strong chemical bonds is underway from the viewpoint of durability and stability of physical properties. That is, the former WPC
In this method, epoxy acrylate is impregnated into wood and cured, and is disclosed in JP-A-60-147303, but epoxy acrylate has a high viscosity in the prepolymer state and is difficult to inject into wood. However, it must be diluted with a solvent that has low affinity for wood components such as styrene and then injected, and it does not react with hydrophilic wood components ((
Therefore, most of the resin is only physically filled in the voids of the wood as a copolymer, increasing the hardness, but the adhesion to the wood structure is poor, resulting in a decrease in softness and flexibility. Unlike the prior art, if a plasticizer or the like is not added, there are problems in that cracks and whitening occur, and machinability deteriorates.

In addition, in the case of polymeric substances such as epoxy acrylate, the polymerization and curing of the nil monomer may be inhibited by the phenols and quinones in the wood material components. may not be applicable.

On the other hand, phenolic polymeric substances have high polarity (and can be used to swell and harden wood materials using water-based solvents, so they have long been used as reinforced rice, but phenolic resins themselves and these The strong acid catalyst used for polymerization weakens the wood material, causing cracks, discoloration, and color unevenness.

On the other hand, some of the latter types of chemically modified wood are made by reacting epoxy compounds with hydroxyl groups in the wood, as disclosed in Japanese Patent Application No. 59-9041, but the above epoxy compounds are of the glycidyl ether type with bisphenol A-epichlorohydrin. It is a solid or highly viscous material that can be chemically bonded to the wood by performing cross-roll operation with small pieces of wood such as wood flour, forming, and then hot pressing.

Therefore, it is difficult to impregnate wood blocks or thin wood boards, and it is even more difficult to chemically modify the hydroxyl groups in the wood components without impairing the cosmetic properties and workability of the wood. there were.

Therefore, the inventor invented a method of obtaining modified wood with excellent stain resistance and dimensional stability by chemically modifying it in advance and then injecting and solidifying it with a polymerizable substance (Japanese Patent Application Laid-open No. 60-242002). requires a two-step process,
There were problems in terms of productivity.

〔the purpose〕

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to easily penetrate into wood materials, react with the active groups in the wood components, and solidify by ring-opening polymerization. To provide modified wood that has both hardness and softness by fixing and solidifying inside the wood and chemically modifying the wood material without impairing the original cosmetic properties of the wood material, and which maintains durability and beauty for a long time. It is in.

[Means for solving problems]

In order to solve such problems, the present invention: (1) chemically modifies the epoxidized higher fatty acid ester of active groups such as hydroxyl groups in the wood component; is polymerized and cured.

; is adopted as a technical means.

[For production]

■ The epoxidized higher fatty acid ester used in the present invention is
Since it is an internal olefin epoxide, a mixture with novolacs or a mixture with a reaction catalyst added as necessary is
It has a low viscosity and is stable under normal conditions, so it can easily and uniformly penetrate wood-based materials.

(2) The epoxy group reacts with the phenolic hydroxyl group of the novolac resin, and since no strong acid catalyst is used at this time, the wood material is less discolored and less brittle. In addition, since the cured resin has flexibility and toughness, it makes the modified wood less prone to cracking and also improves impact resistance. Furthermore, polymerization is not inhibited even in wood species with a large amount of extracted components such as phenols and quinones in the wood components, and conventional W
Since it can be applied to materials that cannot be converted to 2C, decorative materials with new designs and low-grade materials can also be used.

■ In addition, the polymerized hardened product of epoxidized higher fatty acid ester and novolak resin solidified in the wood voids looks as if oil has been rubbed in, giving it a deep wet-colored appearance similar to an oil finish with suppressed fuzz. exhibits.

(2) Furthermore, when the epoxidized higher fatty acid ester reacts with wood components, it appears as if a lubricant has penetrated between the wood components, imparting flexibility and toughness.

(2) Furthermore, since the side chains of the above-mentioned polymer compounds are reacted and integrated with wood components, they will not be eluted with water, alcohol, etc.

■ In addition, since the above chemical modification, oil injection, and in-house reaction are completed in one operation, productivity is good, and no by-products are generated during the reaction, and all processing liquids are reacted in-house. Therefore, there is no need to drain excess processing liquid or wash it.

As described above, modified wood having deeper toughness and better durability can be easily obtained, and can be used not only for exterior materials but also for building materials such as flooring materials and interior materials, furniture materials, and the like.

〔Example〕

The present invention will be explained in detail below.

As a result of various studies conducted so far on modified wood, it has been found that when wood-based materials are impregnated with a mixture of epoxidized higher fatty acid esters and uncured phenol novolaks, the mixture easily penetrates into the wood-based materials, and the impregnated material When heated, the epoxy group is activated and reacts with the active group of the wood material, and at the same time reacts with the active group of the novolak resin, so that it is cured as one with the wood material. As a result, there is no foul odor, no leaching or migration of low-molecular compounds, the wood texture is sufficiently maintained, the color tone does not darken like conventional phenolic resins, and it has a high degree of toughness. The present invention was completed by discovering that That is, the present invention involves chemical modification and WPC conversion, which is characterized by impregnating and reacting a mixed solution of epoxidized higher fatty acid ester and uncured phenol novolatu into a wood material, and solidifying it as one with the wood material. At the same time, we created a chemically modified wood composite material.

The mixed solution of an epoxy compound and a novolak used in the present invention is relatively stable at room temperature, and the curing reaction progresses upon heating, resulting in a cured product that is highly flexible and wear-resistant. In addition, since the phenolic hydroxyl group of novolacs reacts with the epoxy group, the modified wood has excellent color stability.

Unlike the vinyl monomer type used in conventional WPC, the above treatment liquid has good affinity with phenols, quinones, etc. in wood components and does not inhibit arsenization.

The wood-based material may be of any tree species and may have any form such as a piece of wood, but the present invention can be effectively used in the form of a plate or block, particularly thin wood boards, from the viewpoint of productivity, workability, and economy.

In addition, in order to maintain uniform properties of the solidified reactant in any form or tree species, it is desirable to keep the moisture content as low as possible below a certain level (water content 10% or below).

Epoxidized higher fatty acids used in the practice of the present invention include epoxidized triglycerides obtained by epoxidizing linseed oil, soybean oil, etc. with peracid, and unsaturated higher fatty acid monoesters or diesters such as linseed oil fatty acids and soybean oil fatty acids. There are monoesters and diesters of epoxidized higher fatty acids which are epoxidized with peracid, and these can be used alone or in combination. In addition, glycidyl ether of bisphenols, phenol novolak, glycidyl ether of talesol novolak, glycidyl phenol, allyl glycidyl ether, glycidyl methacrylate, and other coloring agents may be used in combination within a range that does not impede impregnation into wood materials. You can also do it. Next, novolaks include phenol novolak, talesol novolak, isobutylphenol novolak, nonylphenol novolak, and ρ-t octylphenol novolak. This is then neutralized or acidified and synthesized by dehydration condensation reaction. Phenols may be used alone or in combination, but preferred are alkyl-substituted phenols such as novolacs.

Catalysts that promote the reaction in the practice of the present invention include Lewis acids, tertiary amines, phosphines, stibine compounds, metal alkoxides, etc.For example, boron trifluoride, monoethylamine complex salts, dimethylbenzylamine, tritylamine,
These include triphenylphosphine, triphenylstibine, tetralinepropoxytitanate, tetrabutoxytitanate, aluminum triisopropoxide, and the like.

These are used by impregnating wood-based materials in advance or by dissolving them in epoxidized higher fatty acid esters.

Although the embodiment of the present invention depends on the form of the wood material,
Basically, the wood material to be treated is dried to below a certain level (moisture content 0.2 to 10%) as industrially possible, placed in an impregnating tank, and treated with epoxidized higher fatty acid esters. Impregnate with a mixed solution of novolacs, to which a reaction catalyst is added if necessary. The viscosity of the impregnation has good affinity with wood materials, so it has the advantage that it can be impregnated under normal pressure. Impregnate only the desired amount, and if the wood material is in the shape of a block or plate, wipe the surface thoroughly and leave it as it is, or cover it with release paper, film, etc. and then heat it to a temperature of 60 to 150℃ under normal pressure or pressure. After heating for several minutes to several hours, the reaction is completed and chemically modified WPC is obtained.

In addition, in the case of blocks or veneers, other than a hot press, the product is applied with a coating device such as paint, and then introduced into a continuous curing device.
Impregnation and curing can also be carried out continuously under heating. In either case, the product has a beautiful glossy oil finish appearance and has excellent pressure resistance, toughness, and water resistance, but the effects of the present invention are best demonstrated with veneer or block materials. be. Examples will be explained in more detail below, but these do not cover the entire scope of the present invention.

(Example 1) Five Douglas fir veneers with a thickness of 1.5 mm, a width of 100 M, and a length of 100 uni were dried at 105° C. for 2 hours to adjust the moisture content to 3%. Separately, 500 g of epoxidized linseed oil (containing 9.2% oxirane oxygen) was reacted with pt-octylphenol and formalin under acidic conditions.

200 g of solid novolac precondensate was heated and dissolved, and 3 parts by weight of tetraisopropoxy titanate was dissolved in 100 parts by weight of this mixed solution to obtain an impregnating liquid.

The impregnating solution was heated to 60° C. and impregnated into the dried veneer under reduced pressure to obtain a Douglas fir veneer with an injection rate of 120%. Excess impregnating liquid was collected and stored at room temperature.

It was found that the pot life of the impregnating liquid was 10 days or more, and that it could be used industrially.

On the other hand, the treatment liquid-impregnated veneer was cured by heating at 140°C for 2 hours.
The resulting treated veneer is light brown and does not turn dark brown like conventional phenolic resin treated rice, retains beautiful wood grain, and has the same flexibility and toughness as untreated raw wood. It was rich in

(Example 2) Using the impregnating solution of Example 1, the thickness was 3 days, the width was 100, and the length was 1.
A rosewood veneer having a diameter of 0.00 mm and a moisture content of 4% was impregnated in the same manner as in Example 1 at an injection rate of 62% to obtain a solidified veneer with an emphasis on the grain of the rosewood. This material had the same toughness as untreated raw material and was excellent in machinability.

〔effect〕

In the present invention, as shown in the ridges, active groups such as hydroxyl groups in wood components are chemically modified with epoxidized higher fatty acid esters, and the epoxidized higher fatty acid esters and novolac resin are polymerized and cured in the voids within the wood. Regarding modified wood, the epoxidized higher fatty acid ester used here is an internal olefin epoxide, unlike conventional epoxy compounds such as glycidyl ether type, so it can be mixed with novolacs or mixed as necessary. A mixed solution containing a reaction catalyst has a low viscosity, is stable under normal conditions, and has the advantage of easily and uniformly penetrating into wood-based materials.

The epoxy group reacts with the phenolic hydroxyl group of the novolac resin, but since no strong acid catalyst is used at this time, the wood material is less likely to discolor and become less brittle.

In addition, since this polymer compound has flexibility and toughness, it makes the modified wood less prone to cracking and also improves impact resistance. Furthermore, polymerization is not inhibited even in wood species that contain a large amount of phenols, quinones, etc. in the wood components, and it can be applied to materials that could not be converted into WPC in the past, so it can be used for cosmetic purposes in new designs and for low-grade materials.

In addition, the polymerized hardened product of epoxidized higher fatty acids and novolac resin solidified in the wood voids creates a state as if oil has been rubbed in, exhibiting water clarity similar to an oil finish, and suppressing fuzz to create a deep wet finish. exhibits the appearance of color.

In addition, when the above-mentioned epoxidized higher fatty acid ester reacts with the wood component together with the novolak resin, it is as if a lubricant has entered between the wood components, which reduces the deformation stress of the wood, imparts toughness, and has the advantage of being less prone to cranking. .

In addition, since the above-mentioned polymer compound reacts and integrates with the wood component in its side chain, it does not elute with water, alcohol, etc., and has good durability.

In addition, since the above chemical modification, resin injection, and in-house reaction are completed in one operation, productivity is high, and no by-products are generated during the reaction, and all of the processing liquid is reacted in-house, so there is no surplus. There is no need to drain or wash the processing solution. Modified wood with greater toughness and durability can be easily obtained, and can be used not only for exterior materials, but also for building materials such as flooring and interior materials, furniture materials, and the like.

Claims (4)

[Claims] (1) A modification characterized in that the epoxidized higher fatty acid ester of active groups such as hydroxyl groups in the wood component is chemically modified, and the epoxidized higher fatty acid ester and novolac resin are polymerized and cured in the voids within the wood. Quality wood. (2) The modified wood according to claim 1, wherein the epoxidized higher fatty acid ester is epoxidized linseed oil. (3) The modified wood according to claim 1, wherein the epoxidized higher fatty acid ester is epoxidized soybean oil. (4) The modified wood according to claim 1, wherein the novolac is an alkyl-substituted phenol novolak.