JPH0716925B2 - Modified wood - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention improves the characteristics such as aesthetics of a wood material by chemically treating the wood material and at the same time filling and curing the polymer compound in the voids of the wood. The present invention relates to a modified wood which has improved durability, hardness and toughness without being damaged.

[Prior art and its problems]

The method of combining the wood material and the synthetic resin is roughly classified into a method of filling the voids in the wood material with a polymerizable substance (so-called
What is called WPC) and a method of reacting oxides and acid anhydrides with functional groups such as hydroxyl groups in components of wood materials to etherify and esterify (so-called chemically modified wood). There are various types of the above-mentioned polymerizable substances and chemical modifiers, and at present, research on epoxy compounds having a strong chemical bond from the viewpoint of durability and physical property stability is under way. That is, in the former WPC, the epoxy acrylate is impregnated and cured in wood.
Although it is disclosed in Japanese Patent Publication No. 147303, the epoxy acrylate has a high viscosity in a prepolymer state and is difficult to be injected into a wood material, and separately diluted with a solvent having a low affinity with a wood component such as styrene. Need to be injected,
Hard to react with hydrophilic wood components. Therefore, most of the resin is only physically filled as a copolymer in the voids of the wood material, and the hardness increases, but since the adhesion to the wood structure is poor, the toughness and flexibility are reduced, and cracks However, there are problems such as whitening, whitening, and poor machinability.

On the other hand, there is a chemically modified wood of the latter which reacts an epoxy compound with a hydroxyl group in a wood material as in Japanese Patent Application No. 59-9041. The epoxy compound is a glycidyl ether type with bisphenol A-epichlorohydrin. It is possible to finally form a chemical bond with wood by kneading with a solid or high-viscosity small piece of wood such as wood powder, performing a roll operation, and hot pressing after forming. Therefore, it is difficult to impregnate a wood block or a wood thin plate, let alone chemically modify with a hydroxyl group in wood components in wood, and there is a drawback that it cannot be modified without impairing the cosmetic properties and processability of wood. there were.

Therefore, the inventor has invented to obtain a modified wood excellent in stain resistance and dimensional stability by a method of injecting and solidifying a polymerizable substance after being chemically modified in advance (JP-A-60-242002). However, there is a problem in terms of productivity because it requires a two-step treatment.

〔Purpose〕

The present invention has been made in view of the above-mentioned drawbacks, and the intended treatment thereof easily penetrates into the wood material and reacts with the active groups in the wood component to polymerize and polymerize by itself. Modified wood that can be hardened and solidified to chemically modify the wood material without impairing the original cosmetic properties of the wood material to have hardness and toughness, and that can maintain durability and aesthetics for a long period of time. To provide.

[Means for solving problems]

In order to solve the above problems, the present invention chemically modifies active groups such as hydroxyl groups in wood components with epoxidized higher fatty acid esters and polybasic acid anhydrides.

The epoxidized higher fatty acid ester and the esterified polymer compound of polybasic acid anhydride are produced in the voids in the wood and filled in the voids in the wood.

Is adopted as a technical means.

[Function] The epoxidized higher fatty acid ester used in the present invention is
Since it is an internal olefin epoxide, the mixture of polybasic acid anhydride or the mixture containing polybasic acid if necessary has low viscosity and is stable in the normal state, so it easily and uniformly penetrates into wood-based materials, The active groups in the component are brought into contact with each other.

After injection, the active groups such as hydroxyl groups in the wood component become initiators by heating and the like, and chemical modification occurs in the material, and the epoxy groups and acid anhydrides are esterified one after another to polymerize,
The chemical modification process and the resin injection process are efficiently performed simultaneously in the wood material.

The epoxidized higher fatty acid ester reacts with the wood component together with the polybasic acid anhydride, and it becomes as if a lubricant entered between the wood components, and flexibility and toughness are imparted.

The polymer compound of epoxidized higher fatty acid ester and polybasic acid anhydride solidified in the voids of wood becomes a state in which oil and fat are rubbed in, and exhibits water repellency like an oil finish without using a plasticizer as in the past. Along with it, it has a deep wet color appearance with suppressed fuzz.

In addition, the pressure resistance is also improved.

Since the polymer compound is chemically bonded to the wood component at the side chain, the polymer compound does not elute with water or alcohol and has good durability.

In the production of this modified wood, chemical modification, resin injection, and reaction within the material are completed in one operation, so productivity is good, and by-products are not generated during the reaction, and the treatment liquid Does not need to be dewatered or washed.

〔Example〕

 Hereinafter, the present invention will be described in detail.

When a wood-based material is impregnated with a mixed solution of an epoxidized higher fatty acid ester and a polybasic acid anhydride or, if necessary, a mixed solution in which a polybasic acid is mixed, the mixed solution easily penetrates into the wood-based material. When the impregnating material is heated at room temperature or heated, or further heated under the use of a catalyst, water and hydroxyl groups in the wood-based material become an initiator, and the impregnating liquid is chemically bonded to the wood-based material,
It is fixed integrally. At this time, the present invention was completed by finding that there is no odor or leaching of by-product, and the wood texture is sufficiently retained. That is, in the present invention, the epoxidized higher fatty acid ester and the polybasic acid are used in order to efficiently perform the reaction of esterifying the epoxy group and the acid anhydride group one after another with the hydroxyl group as the initiator to increase the molecular weight in the wood-based material. Impregnation of a mixed solution of anhydride or a mixed solution of this mixed solution and a polybasic acid into a wood-based material or a wood material that has been carboxyesterified in advance, and at the same time chemical modification and WPC formation by causing an ester reaction in the wood-based material to solidify It is a "chemically modified wood material" that is characterized by what it does.

The wood-based material that can be used in the present invention may be in any form such as a small piece of wood, but the effect of the present invention can be remarkably utilized in a block shape, a plate shape, etc. From the viewpoint of productivity and productivity, a thin wooden plate is preferable. Regardless of the form, it is necessary to maintain the water content in the material at a constant level (water content of 10% or less) as much as possible industrially. This is because water promotes the reaction and also affects the physical properties of the cured product, and appropriate water plays a role of promoting the reaction even at room temperature. Further, the chemically modified wood preliminarily carboxyesterified with a dibasic anhydride such as maleic anhydride or succinic anhydride can be conveniently used even if it is subjected to the treatment of the present invention.

Epoxidized higher fatty acid esters include epoxidized linseed oil, triglycerides such as epoxidized soybean oil and linseed oil fatty acids, epoxidized higher fatty acid monoesters obtained by epoxidizing monoesters of soybean oil fatty acids, and these alone or It can also be used by mixing. Unlike the glycidyl ether type epoxy compound used in the conventional technology, this epoxy compound has a low viscosity, is particularly highly reactive with an organic carboxylic acid, and is also excellent in impregnating ability for wood materials. There is.

In addition, glycidyl ether of bisphenol, phenol novolac, glycidyl ether of cresol novolac, glycidyl phenol, allyl glycidyl ether, glycidyl methacrylate, and other coloring agents may be used in combination as long as the impregnation property into the wood material is not impaired.

The catalyst that promotes the chemical modification reaction is a Lewis acid, a tertiary amine, a phosphine, a stibine compound, or the like. For example,
Boron trifluoride, monoethylamine complex salt, dimethylbenzylamine, triethylamine, triphenylphosphine,
Such as triphenylstibine. These are used by preliminarily impregnating a wood-based material or by dissolving them in an epoxidized higher fatty acid ester. Further, metal alkoxides such as tetraisopropoxy titanate and aluminum triisopropoxyside are also effective.

Next, polybasic acid anhydride, maleic anhydride, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride,
It includes methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, and copolymers of maleic anhydride with 2-olefin such as ethylene, propylene, isobutylene, and styrene.

The polybasic acid includes maleic acid, fumaric acid, succinic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, acrylic acid and methacrylic acid homopolymers and copolymers. However, the polybasic acid shortens the usable time of the impregnating solution, so the amount used should be as small as possible, or use such as impregnating wood materials in advance and then impregnating epoxidized higher fatty acid esters. The method may be used.

The embodiment of the present invention depends on the form of the wood material, but basically, the wood material to be treated is made to have a water content as constant as industrially possible (for example, 2 to 10%). In an impregnation tank, and impregnated with a mixed liquid of epoxidized higher fatty acid esters and polybasic acid anhydride or a mixed liquid of this mixed liquid and polybasic acid, and, if necessary, a reaction-promoting catalyst added to the above mixed liquid. To do. Various methods of impregnation are known, and examples thereof include a reduced pressure-normal pressure-pressurized method. The impregnation may be performed in the required amount. When the wood material is in a block shape, only the surface layer is impregnated, the adhering mixed liquid is wiped off, and the reaction is carried out for several minutes when heated in an oven at room temperature or at 60 to 150 ° C after covering with release paper or film. After a few hours, a chemically modified WPC material can be obtained. In the case of a block or a single plate, it is possible to use a hot press, and it is also possible to continuously heat and solidify with a continuous curing device for paints and the like.

The product here has the appearance of an oily finish with a beautiful luster.

Hereinafter, the present invention will be described in more detail with reference to the examples that best exhibit the effects of the present invention, but these do not encompass all of the present invention.

(Example 1) Ten veneer veneer veneers having a thickness of 1.5 mm, a width of 100 mm, and a length of 100 mm and ten veil pine veneers were dried in an oven at 105 ° C to adjust the water content to 2 to 5%. Next, to 500 g of epoxidized soybean oil (containing 6.9% of oxirane oxygen) was added maleic anhydride in an amount of 1/2 molar equivalent of the epoxy group, and the mixture was kept at 40 ° C. to dissolve it to obtain an impregnating solution. Each of the veiled hemlock veneer and the bay pine veneer were immersed in the impregnating solution and injected under reduced pressure. The impregnation rate was 130% for the venetian veneer veneer and 120% for the veil pine veneer.

The mixed liquid veneer was allowed to stand in an oven and kept at 140 ° C. for 1 hour to cure the impregnating liquid to be integrated with the veneer to obtain a treated veneer. The treated veneer has a wet color and a deep wood grain pattern, is as flexible and tough as untreated raw wood, and has a saw and
A sharp cutting surface can be formed with a knife, etc., and it has excellent workability, and it has characteristics that conventional WPC does not have.

(Example 2) 3 mm thick, 100 mm wide, 100 mm long rosewood, karin,
Cebra, walnut, and teak veneer each 3 sheets 105 ℃
The water content was adjusted to 2-3% by drying in an oven.

Epoxidized linseed oil (containing 9.2% oxirane oxygen) 500
An impregnating solution was obtained by dissolving an amount of methyltetrahydrophthalic anhydride equivalent to the epoxy in g. This impregnating liquid was injected into each of the above-mentioned single plates under reduced pressure. The injection rate was 65-75%.
The excess impregnating liquid was recovered and stored at room temperature, but it was confirmed that it had a pot life of 30 days or more, and was industrially convenient.

The impregnated veneer was left to stand in an oven for 1 hour at 140 ° C. to carry out a reaction, and the veneer and the impregnating solution were integrated and cured. Unlike polyester resin and MMA radical-curing resin, which are markedly poorly cured in wall nuts and teak materials,
In this example, uniform hardening proceeded very easily, was resistant to pressure, was rich in toughness, and was a treated veneer that had a beautiful wood grain with a wet color depending on the wood quality.

(Comparison 1) As the epoxy-based glycidyl ether-type treating agent, the treated veneer of Example 2 was impregnated with an equal weight mixture of bisphenol A-based liquid epoxy resin and methyltetrahydrophthalic anhydride and injected under reduced pressure. The excess impregnation liquid was recovered as 65 to 75%. The pot life of the recovered liquid at room temperature was the same as in Example 2, but when it was cured at 140 ° C., it took 3 hours or more and the treated veneer was finished in a dark color, which is not preferable in appearance. It was

(Example 3) In advance, as an example using carboxyesterified wood, five oak veneers having a thickness of 3 mm, a width of 100 mm and a length of 100 mm were dried in an oven at 105 ° C for 2 hours to have a water content of 2%. Adjust and inject methyl tetrahydrophthalic anhydride under reduced pressure to increase the injection rate.
30% and kept at 80 ° C. for 3 hours to obtain partially carboxyalkylated wood. Then, a mixed solution obtained by dissolving 500 g of epoxidized linseed oil (containing oxirane oxygen, 9.2%) and phthalic anhydride in a molar equivalent of an epoxy group at 60 ° C. was injected under reduced pressure. The injection rate was adjusted to 70% in combination with the above methyltetrahydrophthalic anhydride. This impregnated veneer was kept at 105 ° C. for 5 hours to proceed with the reaction and obtain a treated veneer. This treated veneer has a beautiful grain of oak wood, which is as flexible as a raw material for a treatment agent with excellent scratch resistance.
It was also tough.

〔effect〕

As described above, the present invention chemically modifies an epoxidized higher fatty acid ester and a polybasic acid anhydride to an active group such as a hydroxyl group in a wood component, and at the same time, creates a normal epoxidized higher fatty acid ester and a polybasic acid anhydride in the voids in the wood. The present invention relates to modified wood in which an esterified polymer compound of the product is formed and filled in the voids in the wood.The epoxidized higher fatty acid ester used here is different from the conventional glycidyl ether type epoxy compound and the internal olefin epoxy. Since it is on the side, the mixed solution of polybasic acid anhydride or the mixed solution of polybasic acid added as needed has low viscosity, and is stable in the normal state, so that it easily and uniformly penetrates into wood-based materials. is there.

Furthermore, after injection, active groups such as hydroxyl groups in the wood component serve as initiators, and both the epoxidized higher fatty acid ester and polybasic acid anhydride are chemically modified in the material, and the epoxy group and polybasic acid anhydride are successively added. By esterifying and polymerizing and filling the voids in the wood, the chemical modification treatment and the resin injection treatment can be efficiently performed in the wood at the same time, and as a result, there is an advantage that the productivity is improved. Also, when the above epoxidized higher fatty acid ester reacts with the wood component together with the polybasic acid anhydride, it becomes as if a lubricant entered between the wood components, reducing the deformation stress of the wood material and at the same time imparting toughness. Therefore, there is an advantage that cracks are less likely to occur.

In addition, the polymer compound of epoxidized higher fatty acid ester and polybasic acid anhydride, which is solidified and integrated in the voids of wood, becomes a state in which oil and fat are rubbed in, exhibiting water repellency like an oil finish and suppressing fuzz. It has a deep wet appearance. In addition, since the hardened polymer compound itself is rich in toughness, there is an advantage that crack resistance and pressure resistance are improved.

As described above, according to the present invention, it is possible to easily obtain a wood material having good toughness and durability, and it is possible to provide a modified wood that can be used not only for exterior materials but also for construction materials such as interior materials and furniture materials. It is a thing.

Claims (5)

[Claims] 1. An active group such as a hydroxyl group in a wood component is chemically modified with an epoxidized higher fatty acid ester and a polybasic acid anhydride, and the epoxidized higher fatty acid ester and an ester of a polybasic acid anhydride are formed in the voids in the wood. Modified wood characterized in that it is formed by forming a modified polymer compound and filling the voids in the wood. 2. The modified wood according to claim 1, wherein the epoxidized higher fatty acid ester is an epoxidized linseed oil. 3. The epoxidized higher fatty acid ester is an epoxidized product of soybean oil.
Modified wood according to item. 4. The modified wood according to claim 1, wherein the polybasic acid anhydride is maleic anhydride or a maleic anhydride copolymer. 5. The modified wood according to claim 1, wherein the polybasic acid anhydride is methyltetrahydrophthalic anhydride.