JPH0681684B2 - Modified wood and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention chemically treats a wood material and at the same time, fills and cures a polymer compound in the voids in the wood material to cure the wood material. The present invention relates to modified wood that improves the durability, hardness, toughness, etc. of wood-based materials without impairing properties.

[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
WPC), and a method of reacting oxides and acid anhydrides with functional groups such as hydroxyl groups in the wood material component 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, an epoxy acrylate is impregnated in wood and cured, and it is disclosed in JP-A-60-147303, but the epoxy acrylate has a high viscosity in the prepolymer state and is woody. It is difficult to inject it into the material, and it is necessary to separately dilute it with a solvent that has a low affinity for wood components such as xylene, and to inject it, and it is difficult to react with hydrophilic wood components, so most of the resin Although it is only physically filled as a copolymer in the voids of the wood material, the hardness increases, but the poor adhesion to the wood tissue reduces the toughness and flexibility, causing cracks and whitening, and cutting. There was a problem that workability deteriorates. or,
Teak wood, walnut wood, and the like had a drawback that extraction components in wood such as phenols and quinones interfere with the polymerization reaction of vinyl groups.

On the other hand, some of the former chemically modified woods react with an epoxy compound and a hydroxyl group in a wood-based 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 object of the invention is to easily penetrate into a woody material and radically polymerizable unsaturated monobasic acid or an epoxidized higher-order compound between monomers or oligomers copolymerized therewith. The fatty acid ester reacts and polymerizes and hardens, and the side chain of this resin bonds with the wood component through the epoxidized higher fatty acid, chemically modifying the wood material without impairing the original cosmetic properties and machinability of the wood material. It is an object to provide a modified wood which can be given a toughness as a quality and can maintain durability and aesthetics for a long period of time.

[Means for solving problems]

In order to solve the above problems, the first invention involves chemically modifying an active group such as a hydroxyl group in a wood component with an epoxidized higher fatty acid ester.

The epoxidized higher fatty acid ester and the radically polymerizable unsaturated monobasic acid are polymerized and cured in the voids in the wood.

In the second aspect of the invention, active groups such as hydroxyl groups in the wood component are chemically modified with epoxidized higher fatty acid ester.

Polymerization and curing of the epoxidized higher fatty acid ester with a radical-polymerizable unsaturated monobasic acid and / or a dibasic acid anhydride and / or a monomer or oligomer copolymerized with the radical-polymerizable unsaturated monobasic acid in the voids in the wood. Excuse me.

In addition, the third invention is to impregnate a wood material together with a polymerization catalyst into a liquid composition containing an epoxidized higher fatty acid ester and a radical-polymerizable unsaturated monobasic acid as essential components. .

The liquid composition impregnated in the wood material is polymerized and cured.

Is adopted as a technical means.

[Operation] The treatment liquid used in the present invention has a low molecular weight and a low viscosity,
It has a good affinity with the active groups of the wood material and easily penetrates into the wood material.

The epoxidized higher fatty acid ester in the above treatment is reacted with an active group such as a hydroxyl group in the wood component to be chemically modified.

Vinyl monomers because the epoxidized higher fatty acid ester reacts between the monomers and oligomers that copolymerize with radically polymerizable unsaturated monobasic acid and dibasic acid anhydride and / or radically polymerizable unsaturated monobasic acid to cause polymerization and curing. Less likely to be affected by the wood extraction component that inhibits the polymerization and curing, and less likely to cause hardening inhibition.

In addition, the side chain of the resin is bonded to the wood component through the epoxidized higher fatty acid.

In this way, the filling treatment liquid reacts with the wood component,
Polymerization occurs in the voids of the wood material.

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

Polymeric compounds such as epoxidized higher fatty acid ester solidified in wood voids and radical-polymerizable unsaturated monobasic acid or monomers and oligomers that copolymerize with it become as if oil and fat were rubbed in, resulting in water repellency like an oil finish. It exhibits a deep wet color appearance with suppressed fluff. In addition, the pressure resistance is also improved.

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

In the production of this modified wood, the injection of the treatment liquid and the reaction within the material are completed in a single operation, so the productivity is good, and by-products do not occur 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.

As a result of various studies up to now on modified wood, epoxidized higher fatty acid ester has good impregnation property into wood materials,
In addition, it was found that the epoxy group undergoes a ring-opening addition reaction with the active group of the wood material, and a radical-polymerizable unsaturated monobasic acid is further reacted with a part of this epoxy group, or mixed for radical polymerization. When a curing agent is added, heat, light,
The present invention has been achieved by finding that it is easily polymerized in a wood material with an electron beam or the like.

That is, the present invention uses a radical polymerizable unsaturated monobasic acid in combination with an epoxidized higher fatty acid ester, if necessary, a dibasic acid anhydride, and mixes or reacts a composition with a curing agent for radical polymerization to produce a woody product. It is a modified wood that is characterized by being impregnated into wood and being hardened and integrated into a wood material by heat, light, electron beams, etc. The treatment liquid used in the present invention is excellent in impregnation property into wood materials, and also excellent in grafting reactivity to wood materials and polymerization reaction, and provides an economical method for treating wood materials. is there. Since the treated wood material has an excellent wood appearance, it is more flexible and adhesive than conventional WPC, and thus can be used in a wide range of applications.

The wood material that can be used in the present invention may be in any form such as block, veneer, chip, fiber, wood powder, etc., but veneer-like material is particularly preferable in view of productivity, workability and economy. Is. In order to promote the graft reaction of the reactant efficiently, the wood material should have a constant water content (0.
2-10%) is desirable.

The epoxidized higher fatty acid ester includes triglyceride such as epoxidized linseed oil and epoxidized soybean oil, and epoxidized monoester of these unsaturated fatty acids.
However, bisphenol-based, phenol novolak-based, cresol novolak-based epoxy compounds or liquid butadiene epoxides, glycidyl methacrylate polymers, copolymers, etc. are used in combination within the range that does not impair the impregnation property of the composition into the wood material. Things don't matter.

As the radically polymerizable unsaturated monobasic acid, acrylic acid,
Examples include methacrylic acid and propionic acid.

Furthermore, styrene, vinyltoluene, divinylbenzene, diallylphthalate, methacrylic acid esters such as methylmethacrylate, ethylmethacrylate as a monomer copolymerizable with the double bond residue of radically polymerizable unsaturated monobasic acid. Acrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate and unsaturated polyester oligomers, bisphenol epoxy methacrylate, glycidylphenol novolac methacrylate, cresol novolac methacrylate, trimethylolpropane trimethacrylate, tri Methylol propane dimethacrylate, glycol dimethacrylates, polyethylene glycol dimethacrylate, polypropylene Glycol monomethacrylate, polypropylene glycol monomethacrylate,
Polyfunctional methacrylates such as polypropylene glycol dimethacrylate, oligomers and the like can be blended as necessary.

Further, as the dibasic acid anhydride, when maleic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride or the like is used, the reaction with free hydroxy in the reaction solution proceeds, so that water resistance and heat resistance are improved. It is preferable because it is further improved.

Further, the dibasic acid anhydride and the monomer or oligomer copolymerizable with the radical-polymerizable unsaturated monobasic acid may be mixed and used, and in adjusting the treatment liquid, the mixing order is appropriately changed or room temperature curing is performed. , Heat treatment, etc.

Examples of the curing agent for radical polymerization include cyclohexanone peroxide, cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, lauroyl peroxide, and t which are ordinary organic peroxides.
-Butyl peroxybenzole, dicumyl peroxide and their accelerators and UV curing accelerators.

Although there are various embodiments of the present invention, basically, the wood material to be treated is dried as industrially as possible, and the epoxidized higher fatty acid ester is added with a radically polymerizable unsaturated monobasic acid (if necessary, Basic acid anhydride), a total of equimolar to 2
Mixed or added to about twice the molar amount and added to the composition with a curing agent for radical polymerization, and then impregnated or dipped into the wood material at room temperature and atmospheric pressure,
Alternatively, after injecting and impregnating by a depressurization method or the like, the composition is continuously irradiated with ultraviolet rays or electron beams to be cured, or heat-cured, or ultraviolet rays or electron beams and heat-curing are used together to complete the curing reaction. Thus, the present invention can be completed. The dibasic acid anhydride can be impregnated into the wood material in advance and reacted with the active hydroxy groups of the wood material.

Hereinafter, the present invention will be described in detail with reference to Examples, but it goes without saying that these do not represent all of the present invention.

(Example 1) Epoxidized linseed oil (containing 9.2% of oxirane oxygen) 500
An approximately equimolar amount (250 g) of methacrylic acid to the epoxy group was dissolved in g and reacted for one week at room temperature, and then 7.5 g of benzoyl peroxide was dissolved to obtain a treatment liquid. The pot life of this treatment liquid was 3 weeks or more at room temperature.

Separately, a veneer with a thickness of 1.5 to 3.0 mm, a width of 100 mm, and a length of 100 mm, each of which is destined for two sheets of hemlock, zebrawood, karin, walnut, and cheek, is dried for 2 hours in an oven at 105 ° C to be a treated veneer did. These veneers were dipped in the treatment liquid and depressurized to promote impregnation. Impregnation rate is 120% Betuga, 75% Zebrawood, 60% Karin, 60% walnut, 45% cheek
Met. This impregnated single plate was covered with a release-treated aluminum foil, allowed to stand at room temperature for 24 hours, and then cured at 105 ° C. for 4 hours. Wall nuts and cheeks, which are usually difficult to cure with only radical-curable resins, were well cured, and the wood grain of each resin was beautiful and emphasized. Moreover, the treated veneer was as flexible as untreated raw wood, and was excellent in machinability.

(Example 2) The treatment liquid of Example 1 was dried at 105 ° C for 2 hours to have a thickness of 1.5 m.
Immersed in a Bay pine veneer of m, width 100 mm, length 100 mm. The impregnation rate was 130%. The impregnated plate was irradiated with ultraviolet rays to gel the treatment liquid on the surface, and then cured at 105 ° C. for 3 hours to obtain a treated veneer. This treated veneer was rich in flexibility with beautifully emphasized grain of bay pine and had excellent machinability.

(Example 3) 500 g of epoxidized soybean oil (containing 6.9% of oxirane oxygen)
In addition, an approximately equimolar amount of methacrylic acid (200
g) was dissolved and reacted at room temperature for 5 days, and then 7 g of benzoyl peroxide and 300 g of methyltetrahydrophthalic anhydride were dissolved to obtain a treatment liquid. The pot life of this treatment liquid was about 5 hours at room temperature.

Separately, 1.5-3.0 mm thick, 100 mm wide, 100 mm long bay pine, hemlock, zebrawood, quince, walnut, 2 each
Each veneer was dried in an oven at 105 ° C for 2 hours to obtain a veneer to be treated. These veneers were dipped in the treatment liquid and depressurized to promote impregnation. Impregnation rate is 130% Bay pine, 1
20%, Zebrawood 70%, Karin 60%, Walnut
It was 55%. This impregnated veneer is covered with a release-treated aluminum foil and left at room temperature for 2 hours, then at 80 ℃ for 30 minutes at 105 ℃.
Curing for 2 hours at 140 ° C. for 1 hour. Well-cured, including walnuts and cheeks, which are insufficiently hardened only with normal radical-curable resins, each resin has beautiful and emphasized wood grain, and is tough and has good machinability. It was also excellent in.

Example 4 A mixture of 71 parts by weight of epoxidized soybean oil (epoxy oxygen content: 6.9%) with 20 parts by weight of methacrylic acid (0.02 parts by weight of hydroquinone) was reacted at 95 ° C. for 3 hours, and then maleic anhydride. A composition comprising 85 parts by weight of a reaction product obtained by adding 9 parts by weight and further reacting at the same temperature for 2 hours, 5 parts by weight of a diallyl phthalate monomer, 10 parts by weight of 2-ethylhexyl acrylate, and 1 part by weight of benzoyl peroxide was prepared in advance. Next, a dry veneer of oak wood and teak wood with a thickness of 1.5 mm is dipped in the above composition, degassed under reduced pressure to impregnate the dry veneer with the composition, wrap with a tetron film and Let it harden for an hour. The hardened veneer has a beautiful oil-finished appearance and was not inferior to the conventional unsaturated polyester resin WPC in terms of physical properties, and was applicable to teak wood as well. . still,
Although the above composition was impregnated into a 2 cm x 1 cm x 1 cm prismatic material of Betsuga and cured, the saturated water absorption state-an ASE value due to the volume change rate between absolutely dry states, an unsaturated polyester resin of about 50% was obtained. It is superior to around 20% of WPC, and there is no change in appearance due to dryness and moisture, and a strong bond with wood is supported.

(Example 5) 300 parts by weight of methacrylic acid and 0.2 parts by weight of hydroquinone were added to 700 parts by weight of epoxidized linseed oil (epoxy oxygen content: 9.5%), preliminarily reacted at 120 ° C for 2.5 hours, and then 150 parts by weight of styrene monomer. Part and 10 parts by weight of benzoyl peroxide were used as a treatment liquid, and a 2 mm-thick bay pine veneer was impregnated with the treatment liquid for 1 hour under reduced pressure, 1 hour under pressure, and 2 hours under pressure. Then, the veneer and the treatment liquid were integrated and cured under contact pressure at 120 ° C. for 20 minutes. The cured veneer has a Yanmatsu pattern aesthetic with spring and autumn reversals, and there is no change in devitrification even after a heat test at 180 ° C for 20 minutes, and there is a large change in appearance even after repeated water absorption and drying. It was found that the veneer and the resin component were firmly bonded together.

〔effect〕

As described above, the first invention involves chemically modifying an epoxidized higher fatty acid ester with an active group such as a hydroxyl group in a wood component, and at the same time, the epoxidized higher fatty acid ester and a radical-polymerizable unsaturated group are formed in the voids in the wood material. A second aspect of the present invention is a modified wood obtained by polymerizing and curing a basic acid. The second invention is to chemically modify an epoxidized higher fatty acid ester with an active group such as a hydroxyl group in a wood component, and the above epoxidized higher fatty acid ester in a void in the wood material. And a radical-polymerizable unsaturated monobasic acid and a monomer copolymerizable with the radical-polymerizable unsaturated monobasic acid,
Since it is a modified wood that is polymerized and hardened with an oligomer,
Unlike conventional epoxy acrylate or polyester resin injected WPC, radical polymerizable unsaturated monobasic acid or monomer that copolymerizes with radical polymerizable unsaturated monobasic acid,
The epoxidized higher fatty acid ester reacts between the oligomers to be polymerized and cured, so that the polymerized resin itself is provided with plasticity properties, and toughness and impact resistance are provided.

In addition, all of the above fillers have low molecular weight and low viscosity,
It has a good affinity with the active groups of the wood material, can easily penetrate into the wood material, and since the side chain of the above resin will be bonded to the wood component via the epoxidized higher fatty acid, The surface sealing effect is increased, the infiltration of water and dyeing substances is reduced, and as a result, there are advantages such as excellent dimensional stability and stain resistance, and small peeling of the coating film even when it is applied to the surface. . In addition, as described above, since it reacts with the wood component and is polymerized in the wood voids, the performance can be maintained for a long period of time without elution with water or alcohol, and the durability is also good.

Further, as in the third invention, the injection of the treatment liquid and the reaction in the material are completed in one operation, so that not only the productivity can be greatly improved, but also by-products are not generated. The conventional solvent removal step and washing step are not required, and workability is improved.

As a result, the treated wood known by the treatment method of the present invention has a beautifully emphasized wood grain, is rich in flexibility and toughness, and has sufficient curability even in a tree species that is insufficiently cured with an unsaturated polyester resin. It was a thing.

Claims (4)

[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 the epoxidized higher fatty acid ester and a radically polymerizable unsaturated monobasic acid are polymerized and cured in voids in the wood. Modified wood that is characterized by 2. An active group such as a hydroxyl group in a wood component is chemically modified with an epoxidized higher fatty acid ester, and the epoxidized higher fatty acid ester and the radical-polymerizable unsaturated monobasic acid and dibasic acid anhydride are present in the voids in the wood. And / or a monomer or oligomer that is copolymerized with the radical-polymerizable unsaturated monobasic acid is polymerized and cured to obtain modified wood. 3. A modified wood material, characterized in that a liquid composition containing an epoxidized higher fatty acid ester and a radical-polymerizable unsaturated monobasic acid as essential components is impregnated into a wood material together with a polymerization catalyst to be polymerized and cured. Production method. 4. The method for producing modified wood according to claim 3, wherein a dibasic acid anhydride and / or a monomer or oligomer copolymerizable with a radical-polymerizable unsaturated monobasic acid is added to the liquid composition.