JPH01174402A - Modified wood - Google Patents

Abstract

PURPOSE:To improve the durability, hardness, toughness and the like of wood without impairing the pretty appearance of the wood by a method wherein the active group such as hydroxyl group or the like in the wood is chemically modified and polymerized by epoxidized higher fatty ester and polybasic acid anhydride. CONSTITUTION:Wood is treated, for example, under reduced pressure by being impregnated with epoxidized higher fatty ester which consists of impregnating liquid which is prepared by adding anhydrous maleic acid to epoxidized soybean oil, and the like. Next, by being heat-treated about one hour at 140 deg.C, the hydroxyl group and the like in the wood component acts as the starter, resulting in developing chemical modification in the wood and simultaneously, in succession, esterifying and polymerizing epoxy group anhydride in order to efficiently and simultaneously perform both the chemical modification treatment and resin pouring treatment. The epoxidized higher fatty eater together with polybasic acid anhydride react with the wood component, resulting in realizing the state as if lubricant enters in the wood component and giving flexibility and toughness to the wood.

Description

[Detailed Description of the Invention] [Industrial Application Field] 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. This invention relates to modified wood that has improved durability, hardness, toughness, etc. without impairing it.

(Prior art and its problems) Methods for combining wood materials and synthetic resins can be roughly divided into two methods: filling voids in the wood material with a polymerizable substance (so-called WPC), and methods for combining wood material and synthetic resin. A method of reacting functional groups such as hydroxyl groups with oxides and acid anhydrides to etherify and esterify wood (so-called chemically modified wood)
There is a way to say that. There are various types of polymerizable substances and chemical modifiers, and research is currently underway on epoxy compounds having strong chemical bonds from the viewpoint of durability and stability of physical properties. That is, in the former WPC, epoxy acrylate is impregnated into wood and cured, and is disclosed in JP-A-60-147303, but the epoxy acrylate has a high viscosity in the prepolymer state and is hardened by wood. It is difficult to inject into the material, and it must be diluted with a solvent that has low affinity for wood components such as styrene before injection, and it does not easily react with hydrophilic wood components. is simply physically filled as a copolymer in the voids of the wood material, and although it increases hardness, it has poor adhesion to the wood structure, resulting in decreased toughness and flexibility, causing cracks and whitening. There was a problem that cutting workability deteriorated.

On the other hand, there is also the latter type of chemically modified wood, as disclosed in Japanese Patent Application No. 59-9041, in which an epoxy compound is reacted with the hydroxyl group in the wood material. It is an ether-type product that is solid or highly viscous and can be chemically bonded with wood by kneading it with small pieces of wood such as wood flour, rolling it, forming it, and then applying heat and pressure. . 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 processability of the wood. There were drawbacks.

Therefore, the inventor devised a method to obtain 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 Unexamined Patent Publication 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 active groups in wood components, and polymerize by itself to form a polymer. By fixing and solidifying the wood material, it is possible to chemically modify the wood material without impairing its original cosmetic properties, thereby maintaining both hardness and toughness.Moreover, it is a modification that maintains durability and aesthetics over a long period of time. To provide wood.

(Means for Solving the Problems) The present invention solves the above problems by: (1) chemically modifying active groups such as hydroxyl groups in wood components with epoxidized higher fatty acid esters and polybasic acid anhydrides;

(2) The esterified polymer compound of the epoxidized higher fatty acid ester and polybasic acid anhydride is produced in the wood voids and filled into the wood voids.

; 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, the mixed solution of polybasic acid anhydride or the mixed solution with polybasic acid added as necessary has a low viscosity and is stable under normal conditions, so it can easily and uniformly penetrate into wood-based materials. It becomes available for contact with active groups in the components.

■ After injection, active groups such as hydroxyl groups in the wood components become initiators by heating, etc., chemical modification occurs in-house, and epoxy groups and acid anhydrides are successively esterified to form a polymer.
Chemical modification treatment and resin injection treatment are carried out simultaneously and efficiently within the wood material.

■ The epoxidized higher fatty acid ester reacts with the wood components together with the polybasic acid anhydride, as if a lubricant had penetrated between the wood layers, imparting flexibility and toughness.

■ The polymeric compound of epoxidized higher fatty acid ester and polybasic acid anhydride solidified in the wood voids becomes a state as if oil and fat have been rubbed in, and it is difficult to use plasticizers as in the past.
It is like an oil finish (it exhibits water damage properties and has a deep, wet-colored appearance with less fluff.

In addition, pressure resistance is also improved.

(2) Since the above-mentioned polymer compound is chemically bonded to wood components through side chains, it is not eluted by water, alcohol, etc., and has good durability. .

■ In addition, in manufacturing this modified wood, chemical modification, resin injection, and in-house reaction are completed in a single operation, so productivity is high, and no by-products are produced during the reaction, and treatment liquid is Since all the reactions are carried out in-house, there is no need to remove excess processing liquid or clean it.

〔Example〕

The present invention will be explained in detail below.

When a wood-based material is impregnated with a mixed solution of an epoxidized higher fatty acid ester and a polybasic acid anhydride, or a mixed solution in which a polybasic acid is mixed as necessary, the mixed solution easily penetrates into the wood-based material. When the impregnated material is heated at room temperature or heated, or further heated with the use of a catalyst, water and hydroxyl groups in the wood material act as initiators, and the impregnating liquid is chemically bonded to the wood material.
integrated and fixed. At this time, it was discovered that there was no bad odor or leaching of by-products, and the woody texture was sufficiently maintained, and the present invention was completed. That is, in the present invention, an epoxidized higher fatty acid ester and a polybasic material are used to efficiently esterify an epoxy group and an acid anhydride group using a hydroxyl group as an initiator to increase the molecular weight in a wood-based material. Chemical modification and W2C conversion are carried out by impregnating a mixed solution of an acid 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 converted into a carboxyester in advance, and causing an ester reaction in the wood-based material to solidify. This is a wood material 1 that has been chemically modified.

The wood-based material that can be used in the present invention may be in any form such as small pieces of wood, but the effects of the present invention can be particularly effectively utilized in blocks, plates, etc. Wood thin plates are preferable from the viewpoint of performance and productivity. Regardless of the form, the moisture content in the wood must be maintained at a constant level (moisture content of 10% or less) as far as industrially possible. This is because water accelerates the reaction and also affects the physical properties of the cured product, and an appropriate amount of water plays a role in promoting the reaction even at room temperature. Furthermore, chemically modified wood that has been previously carboxyesterified with a dibasic acid anhydride such as maleic anhydride or succinic anhydride can be advantageously used by applying the treatment of the present invention.

Epoxidized higher fatty acid esters include triglycerides such as epoxidized linseed oil and epoxidized soybean oil, and epoxidized higher fatty acid monoesters, which are obtained by epoxidizing monoesters of linseed oil fatty acids and soybean oil fatty acids. They can also be used in combination. Unlike the glycidyl ether type epoxy compounds used in conventional technology, this epoxy compound has a low viscosity, is highly reactive with organic carboxylic acids, and has excellent impregnation properties into wood materials. ing.

In addition, glycidyl ether of bisphenol, phenol novolac, glycidyl ether of talesol novolak, glycidyl phenol, allyl glycidyl ether, glycidyl methacrylate, and other coloring agents may be used in combination as long as they do not impede the impregnation into the wood material. .

Catalysts that promote chemical modification reactions include Lewis acids, tertiary amines, phosphine, and stibine compounds. for example,
Boron trifluoride, monoethylamine complex salt, dimethylbenzylamine, triethylamine, triphenylphosphine,
Such as triphenylstibine. These are used by impregnating wood-based materials in advance or by dissolving them in epoxidized higher fatty acid esters. Also effective are metal alkoxides such as tetraisopropoxy titanate and aluminum triisopropoxide.

Next, polybasic acids include maleic anhydride, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. Copolymers of maleic anhydride and 2-olefins such as ethylene, propylene, isobutylene, and styrene are encapsulated.

Polybasic acids include homopolymers and copolymers of maleic acid, fumaric acid, succinic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, acrylic acid, and methacrylic acid. However, since polybasic acids shorten the usable life of the impregnating liquid, the amount used should be as small as possible, or the use of polybasic acids should be impregnated into wood materials in advance and then impregnated with epoxidized higher fatty acid esters. law may be adopted.

The mode of implementation of the present invention depends on the form of the wood material, but basically the wood material to be treated has a moisture content as constant as industrially possible (for example, 2 to 10%).
This is placed in an impregnation tank, and a mixture of epoxidized higher fatty acid esters and polybasic acid anhydride, or a mixture of this mixture and polybasic acid, and if necessary, a reaction accelerating catalyst is added to the above mixture. Impregnate. Various methods of impregnation are known, such as a reduced pressure-normal pressure-pressure method. You only need to impregnate the required amount. If the wood material is in the form of a block, impregnate only the surface layer, wipe off the adhering mixture, and leave it at room temperature or cover it with release paper or film and then heat it to 60-150°C. When heated in an open state at a temperature of , the reaction is completed in several minutes to several hours, and a chemically modified WPC material is obtained. In addition, in the case of a block or a veneer, it is possible to use a hot press, and it is also possible to continuously heat and solidify the material using a continuous curing device for paints or the like.

The product then has a beautiful glossy oil finish appearance.

EXAMPLES Hereinafter, the present invention will be explained in detail using examples that best exhibit the effects of the present invention, but these do not encompass the entirety of the present invention.

(Example 1) 10 Hemlock veneers and 10 Douglas fir veneers with a thickness of 1.5 mm, a width of 100 fl, and a length of 100 mm were dried in an oven at 105°C and the moisture content was adjusted to 2 to 5%. 0 then epoxidized soybean oil (containing 6.9% oxirane oxygen) 500
A molar equivalent of maleic anhydride of the epoxy group was added to g, and the mixture was maintained at 40°C to dissolve it, thereby obtaining an impregnating solution. A hemlock veneer and a Douglas fir veneer were soaked in the impregnating solution and injected under reduced pressure. The impregnation rate was 130% for the Japanese hemlock veneer and 120% for the Douglas fir veneer.

The mixed solution veneer was placed in an oven and kept at 140° C. for 1 hour to harden the impregnating liquid and integrate it with the veneer to obtain a treated veneer. Treated veneer has a wet color and a deep wood grain pattern, and has the flexibility and toughness of untreated raw wood, and is suitable for sawing,
It was unique in that it could form a sharp cut surface with a knife and had excellent workability, which was not found in conventional WPC.

(Example 2) Rosewood with a thickness of 3 cranes, a width of 100 cranes, and a length of 1°00 cranes,
Three veneers each of quince, cebra, walnut, and teak were dried in an oven at 105°C to adjust the moisture content to 2 to 3%.

Epoxidized linseed oil (contains 9.2% oxirane oxygen)
An impregnating solution was obtained by dissolving methyltetrahydrophthalic anhydride in an amount equal to that of the epoxy in 500 g.

This impregnation liquid was injected into each of the above-mentioned veneers under reduced pressure. The injection rate was 65-75%. The excess impregnating liquid was collected and stored at room temperature, and it was confirmed that the product had a pot life of 30 days or more and was industrially easy to use. ``The impregnated veneer was placed in an oven and kept at 140° C. for 1 hour to carry out a reaction, and the veneer and the impregnating liquid were integrated and cured. Unlike polyester resins and MMA radical curing resins, which have remarkable curing defects in walnut and teak materials, this example cures uniformly very easily, has pressure resistance, and is rich in toughness. The treated veneer has a beautiful wood grain that is expressed in wet colors depending on the wood quality.

(Comparison example 1) ゛Execution using a glycidyl ether type treatment agent for epoxy The treated veneer of Bowl 2 was impregnated with a mixture of equal weights of bisphenol A-based liquid epoxy resin and methyltetrahydrophthalic anhydride, injected under reduced pressure, and injected in the same way. The pot life at room temperature of the zero-recovered liquid, in which the excess impregnating liquid was recovered at a ratio of 65 to 75%, was the same as in Example 2, but when it was cured at 140°C, it required more than 3 hours. The treated veneer had a dark color and was unfavorable in terms of appearance.

(Example 3) As an example using carboxyesterified wood, an oak veneer 5 with a thickness of 3 layers, a width of 100 m, and a length of 100 fi was prepared in advance.
Dry the sheet in an oven at 105℃ for 2 hours to reduce the moisture content to 2.
%, methyltetrahydrophthalic anhydride was injected under reduced pressure to make the injection rate 30%, and the mixture was kept at 80'C for 3 hours to obtain partially carboxyalkylated wood. (contains oxygen, 9.2%)
A mixture obtained by dissolving phthalic anhydride in a molar equivalent of epoxy group in 500 g while maintaining the temperature at 60°C was injected under reduced pressure. The injection rate was adjusted to 70% including the above-mentioned methyltetrahydrophthalic anhydride. 20 Impregnated veneer at 105°C
The reaction mixture was maintained for 5 hours to advance the reaction, and a treated veneer was obtained. This treated veneer brought out the beautiful grain of the oak wood, was as flexible as treated raw wood with excellent scratch resistance, and was highly tough.

〔effect〕

The present invention involves chemically modifying active groups such as hydroxyl groups in wood components with epoxidized higher fatty acid esters and polybasic acid anhydrides as shown on the ridges, and pressurized air epoxidation of higher fatty acid esters and polybasic acid anhydrides in the voids within the wood. This relates to modified wood in which an esterified polymer compound is produced and filled into the voids within the wood.The epoxidized higher fatty acid ester used here is an internal olefin epoxide, unlike conventional epoxy compounds such as glycidyl ether type. Therefore, mixtures of polybasic acid anhydrides or mixtures with polybasic acids added as necessary have low viscosity and are stable under normal conditions, so they can easily and uniformly penetrate wood-based materials. .

Furthermore, after injection, active groups such as hydroxyl groups in the wood components act as initiators, and both the epoxidized higher fatty acid ester and polybasic acid anhydride are chemically modified in-house, and the epoxy group and polybasic acid anhydride are converted into esters one after another. By converting it into a polymer and filling it into the voids within the wood, chemical modification treatment and resin injection treatment can be carried out efficiently at the same time within the wood, which has the advantage of contributing to improved productivity. In addition, when the above-mentioned epoxidized higher fatty acid ester reacts with the wood component together with the polybasic acid anhydride, it becomes as if a lubricant has penetrated between the wood components, reducing the deformation stress of the wood material and at the same time imparting flexibility. This has the advantage that cranking is less likely to occur.

In addition, the polymeric compound of epoxidized higher fatty acid ester and polybasic acid anhydride solidified and integrated into the wood voids creates a state as if oil has been rubbed in, exhibiting water repellency like an oil finish and eliminating fuzz. It is pressed down and has a deep wet color appearance. In addition, since the hardened polymer compound itself has high toughness, it has the advantage of improving crack resistance and pressure resistance.

From the above, the present invention makes it possible to easily obtain a wood material with deep toughness and good durability, and to provide a modified wood that can be used not only for exterior materials, but also for construction materials such as interior materials, furniture materials, etc. It is something.

one

Claims (5)

[Claims] (1) Active groups such as hydroxyl groups in wood components are chemically modified with epoxidized higher fatty acid esters and polybasic acid anhydrides, and the epoxidized higher fatty acid esters and polybasic acid anhydrides are esterified in the voids within the wood. A modified wood characterized by forming a molecular compound and filling the voids within the wood. (2) The modified wood according to claim 1, wherein the epoxidized higher fatty acid ester is an epoxidized product of linseed oil. (3) The modified wood according to claim 1, wherein the epoxidized higher fatty acid ester is an epoxidized product of soybean oil. (4) Claim 1, characterized in that the polybasic acid anhydride is maleic anhydride or a maleic anhydride copolymer.
Modified wood as described in Section. (5) The modified wood according to claim 1, wherein the polybasic acid anhydride is methyltetrahydrophthalic anhydride.