JPH07256610A - Production of modified wood - Google Patents

Abstract

PURPOSE:To obtain a method for industrially easily producing a modified wood exerting a water-resistant dimensional stability for a long term. CONSTITUTION:A wood material is impregnated with a aqueous solution prepared by adding a catalyst accelerating a reaction to a polyalkylene glycol glycidyl ether resin, thereafter being heated for curing the resin. Under this treatment, the groups of the polyalkylene glycol glycidyl ether are bonded to each other by epoxy linkages in the material to be charged in the material as a bonded substance having a water resistance. In the obtained modified wood material, even if the treated wood material comes into contact with water, the decomposition and removal of the charged resin is prevented by the ether reaction of the epoxy resin of the polyalkylene glycol glycidyl ether with a part of hydroxyl groups and carboxyl groups as components of the wood material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing modified wood capable of imparting water-resistant dimensional stability to wood over a long period of time.

[0002]

2. Description of the Related Art Since wood is hydrophilic, it absorbs water,
It is known that it expands and contracts upon release and has poor dimensional stability. This is because water enters and leaves the pores of the cell wall of wood, causing expansion and contraction,
In order to prevent this expansion and contraction, the treatment liquid is impregnated into the voids of the cell wall to expand it, and the treatment liquid is cured in the expanded state so that the water content can be adjusted regardless of the water content. Dimensional stabilizing means is adopted that has a mechanism that does not expand and contract.

In such a dimension stabilizing means for wood, the above-mentioned treatment liquid to be impregnated into the pores of the cell wall of wood must be a water-soluble one which penetrates into the minute pores of hydrophilic wood, Conventionally, polyethylene glycol or polyethylene glycol methacrylate obtained by radical polymerization of polyethylene glycol has been used as such a treatment liquid.

[0004]

However, since polyethylene glycol is hydrolyzed, it is easily dissolved in water, and is eluted from the voids of the cell wall to be raised on the wood surface, and when it is repeatedly immersed in water, dimensional stability is extremely high. However, there was a problem that Further, the latter polyethylene glycol methacrylate is polymerized between the side chains of the compound, but there is a problem that the side chains are likely to be fragmented and the dimensional stability of wood deteriorates when used for a long period of time.

The present invention has been made in view of the above problems. A first object of the present invention is to provide a method for producing modified wood capable of exhibiting water resistance and dimensional stability over a long period of time. To provide. Further, a second object of the present invention is to provide a method capable of industrially and easily producing the modified wood having stable quality. Still another object of the present invention is to provide modified wood having antiseptic and insect repellent properties.

[0006]

In order to achieve the above-mentioned first object, the method for producing modified wood of the present invention comprises, as described in claim 1, impregnating wood with an alkylene glycol glycidyl ether aqueous solution, It is characterized by heating to cure alkylene glycol glycidyl ether in wood.

In order to achieve the second object, the method for producing modified wood of the present invention is, as described in claim 2, wood, alkylene glycol glycidyl ether, amines, amides and ammonium. It is characterized in that an alkylene glycol glycidyl ether is cured in wood by impregnating with an aqueous solution prepared by mixing a catalyst composed of either a salt or a dicarboxylic acid compound and heating.

Further, as described in claim 3, in the invention described in claim 2, the third object can be achieved by using a quaternary ammonium salt as a catalyst.

[0009]

[Function] The alkylene glycol glycidyl ether aqueous solution has good penetrability into wood, and easily penetrates even fine pores of wood. When wood is impregnated with an aqueous solution of alkylene glycol glycidyl ether, the alkylene glycol glycidyl ether is epoxy-bonded to each other inside the wood, and the compound is filled in the wood voids as a water resistant compound. Furthermore, some of the hydroxyl groups or carboxyl groups in the wood component and the epoxy groups of the alkylene glycol glycidyl ether undergo an ether reaction, and after curing, even if they come into contact with moisture, decomposition or shedding from the wood is less likely to occur.

Furthermore, in the invention described in claim 2, an alkylene glycol glycidyl ether is impregnated with an aqueous solution prepared by mixing a catalyst comprising any of amines, amides, ammonium salts or dicarboxylic acid compounds, Since it is heated and cured in wood, curing is promoted by the above catalyst, uniform reaction and reduction of reaction time can be achieved, and quality is stabilized and productivity is improved.

Further, as described in claim 3, when a quaternary ammonium salt is used as a catalyst, since the quaternary ammonium is a cation, the quaternary ammonium salt is firmly bound to the anion site in the wood component. It exerts a strong antibacterial effect and imparts antibacterial and antifungal properties to wood. The modified wood treated with the above aqueous solution maintains the same workability and handleability as untreated wood when nailing or cutting.

[0012]

[Examples] Explaining in detail the examples of the present invention, as the wood to be modified, a veneer or a lumber with a thickness of about 0.5 to several tens mm can be adopted, and the water content thereof is not particularly limited. 15
% Or less is preferable because it can prevent the occurrence of cracks and the like. On the other hand, an alkylene glycol glycidyl ether having a molecular weight of 150 to 6000 is used as the agent for modifying the wood.

The alkylene glycol glycidyl ether may be either a polyalkylene glycol glycidyl ether or a monoalkylene glycol glycidyl ether, specifically, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol polyglycidyl ether, (Mono) ethylene glycol diglycidyl ether, (mono) propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether,
1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, sorbitol polyglycidyl ether and the like are used.

This alkylene glycol glycidyl ether is added to water or an organic solvent compatible with water such as alcohols to prepare an alkylene glycol glycidyl ether aqueous solution, and the pressure is reduced to 100 mmHg or less, or 3
Pressurize at kgf / cm ² , or combine them or repeat multiple times, depending on the shape and thickness of the wood, and forcefully inject and impregnate the wood. In this case, the alkylene glycol glycidyl ether aqueous solution may be injected alone into the wood, but a catalyst for accelerating the reaction may be added to the alkylene glycol glycidyl ether aqueous solution, and this mixed aqueous solution may be injected into the wood. . The concentration of the alkylene glycol glycidyl ether in the mixed aqueous solution is in the range of 5 to 30% by weight, and is set so that 10 to 60% based on the dry weight of the wood is obtained by injecting and impregnating the wood and drying.

As the catalyst, any of amines, amides, ammonium salts, and dicarboxylic acid compounds is used. Specifically, ethylenediamine and n are used.
-Amine such as butylamine, amide compound, quaternary ammonium salt such as tetraethylammonium chloride, sodium hydroxide, potassium hydroxide, oxalic acid, maleic anhydride, etc. can be used, and the concentration in the mixed aqueous solution is 0.1-10.
It is selected in the range of%.

The above alkylene glycol glycidyl ether aqueous solution has good permeability to wood, and easily permeates into the pores of the fine cell walls of wood in a short time by forced injection by the pressure reduction / pressure method. Wood that has been impregnated and impregnated with an aqueous solution of alkylene glycol glycidyl ether may be heated at 60 to 200 ° C for several minutes by hot air, high frequency, or hot pressure.
Heat for 1 day to cure the alkylene glycol glycidyl ether.

At this time, the alkylene glycol glycidyl ethers are epoxy-bonded to each other in the material and cured while being filled in the voids of the wood as a compound having water resistance. Part of the hydroxyl groups or carboxyl groups and the epoxy groups of alkylene glycol glycidyl ether undergo an ether reaction, and after curing, even if it comes into contact with moisture, the above-mentioned filling compound is unlikely to decompose or fall off from the wood.

When a catalyst comprising any of the above amines, amides, ammonium salts, or dicarboxylic acid compounds is mixed in the alkylene glycol glycidyl ether aqueous solution, these catalysts may be added during the curing treatment by heating. The catalyst accelerates the curing of the alkylene glycol glycidyl ether, and the uniform reaction and the shortening of the reaction time can be achieved, and the modified wood of excellent quality can be stably and efficiently produced.

Further, when a quaternary ammonium salt is used as a catalyst, the quaternary ammonium is a cation,
It strongly binds to an anion site in the wood component, exerts a strong antibacterial action, and can impart antibacterial and antifungal properties to wood. The modified wood thus obtained can be nailed or cut in the same manner as untreated wood, and is excellent in processability and handleability. Hereinafter, specific examples and comparative examples of the present invention will be shown.

Example 1 A 30% aqueous solution of polyethylene glycol diglycidyl ether (molecular weight: about 530) was applied to five test pieces of Betsuga lumber (width 30 mm × thickness 10 mm × length 30 mm).
Reduce the pressure below mmHg for 1 hour, pressurize at 5 kgf / cm ² for 12 hours,
After pouring, it was dried in an oven at 105 ° C for 12 hours to accelerate the reaction and cure. The weight increase rate of these five test pieces is 56% on average, 6.5% in the radial direction (width),
There was a so-called bulking phenomenon with 4.0% expansion in the tangential direction (thickness).

The above five test pieces were immersed in tap water, depressurized, and then pressurized to forcibly absorb water, and then dried at 105 ° C. for 12 hours. The treatment process from dipping to drying is set as one cycle, and each sample is repeatedly treated for 5 cycles to measure the radial dimension and shrinkage ratio at each time, and the untreated material is treated under the same conditions. Each anti-contraction ability ASE compared with the contraction rate
I asked. Further, the resin residual rate in each cycle was obtained. The results are shown in Table 1.

[Comparative Example 1] A 30% aqueous solution of polyethylene glycol (molecular weight: about 1000) was used as a treatment liquid, and the same shape and the same size of Bettsuga lumber as in Example 1 were treated under the same conditions. The ASE value of this treated veneer was determined under the same conditions as in Example 1. Further, the resin residual rate in each cycle was obtained. The results are shown in Table 1. The bulking rate of the treated veneer was 7.2% in the radial direction and 4.0% in the tangential direction.

As is clear from this table, in Example 1 of the present invention, the ASE value in the first cycle was 62% and in the final cycle it was 57%. In Comparative Example 1, the bulking effect of polyethylene glycol was excellent and the ASE value of the anti-swelling ability was about 88% in the first cycle, but since the resin leaching was large, the AS in the final cycle was
The E value has dropped to 22%.

[0024]

[Table 1]

[Example 2] Polypropylene glycol diglycidyl ether (molecular weight: about 520) was used as a treatment liquid in an amount of 30.
Part, ethyl alcohol 23 parts, water 47 parts water mixed with 0.5 parts of tetraethylammonium bromide as a catalyst to prepare an aqueous solution of Batsuga lumber (width 30 mm × thickness 10 mm × length 30 m).
m) Five test pieces were injected by the vacuum / pressurization method as in Example 1, and then dried in an oven at 105 ° C for 12 hours to accelerate the reaction and cure. The weight increase rate of these five test pieces was 59% on average, and the so-called bulking phenomenon appeared due to expansion of 6.6% in the radial direction (width) and 3.9% in the tangential direction (thickness).

The above five test pieces were immersed in tap water, depressurized, and then pressed to force the test pieces to absorb water, and then dried at 105 ° C. for 12 hours. The treatment process from dipping to drying is set as one cycle, and each sample is repeatedly treated for 5 cycles to measure the radial dimension and shrinkage ratio at each time, and the untreated material is treated under the same conditions. Each anti-contraction ability ASE compared with the contraction rate
I asked. Further, the resin residual rate in each cycle was obtained. The results are shown in Table 2. For the treated material produced in Example 2, the antiseptic efficacy value was measured according to JISA9201 "Performance standard of wood antiseptic and production method", and Table 3
Got

Comparative Example 2 Example 2 was carried out by using an aqueous solution containing 30% polyethylene glycol methacrylate (molecular weight about 350) as a treatment liquid and 3% ammonium persulfate as a catalyst.
Batsuga lumber with the same shape and size was treated under the same conditions. The ASE value of this treated veneer was determined under the same conditions as in Example 2. Further, the resin residual rate in each cycle was obtained. The results are shown in Table 2. The bulking rate of the treated veneer was 6.9% in the radial direction and 4.1% in the tangential direction.

[0028]

[Table 2]

As is clear from this table, in Example 2 of the present invention, the ASE value in the first cycle was 49% and the final cycle was 47%, and almost no decrease in the ASE value was observed. The residual rate of the injected resin was 71% in the fourth cycle. On the other hand, in Comparative Example 2, the ASE value was 72% in the first cycle, but the ASE value decreased to 20% in the final cycle, and the residual resin ratio was also 5th cycle. It was only 35%.

[0030]

[Table 3]

Example 3 Example 3 was obtained by performing the same treatment as in Example 1 except that polyethylene glycol diglycidyl ether was changed to monoethylene glycol diglycidyl ether (molecular weight 142). Then, the anti-swelling rate and the resin residual rate were determined by the same test method and are shown in Table 4.

[0032]

[Table 4]

[0033]

As described above, according to the method for producing modified wood of the present invention, the wood is impregnated with the alkylene glycol glycidyl ether aqueous solution and heated to cure the alkylene glycol glycidyl ether in the wood. , Alkylene glycol glycidyl ether has good permeability to wood and can be easily penetrated into the fine voids of wood, and after hardening, it is firmly integrated with wood components in the wood to change the water content of wood. Despite this, it can exhibit excellent water resistance and dimensional stability over a long period of time, and in addition, it can be processed and handled in the same way as untreated wood, such as nailing and cutting. It is a thing.

Further, wood is impregnated with an aqueous solution prepared by mixing the above-mentioned alkylene glycol glycidyl ether with a catalyst consisting of alkylene glycol glycidyl ether and any of amines, amides, ammonium salts, or dicarboxylic acid compounds. The modified wood which promotes the treatment reaction and is stable in quality can be industrially easily produced. Furthermore, by using a quaternary ammonium salt as a catalyst, it is possible to impart antibacterial and antifungal properties to wood for a long period of time.

Claims (3)

[Claims] 1. A method for producing modified wood, which comprises impregnating wood with an aqueous solution of alkylene glycol glycidyl ether and heating the wood to cure the alkylene glycol glycidyl ether in the wood. 2. Wood is impregnated with an aqueous solution of alkylene glycol glycidyl ether mixed with a catalyst comprising any of amines, amides, ammonium salts, or dicarboxylic acid compounds, and heated to heat the alkylene in the wood. A method for producing modified wood, which comprises curing glycol glycidyl ether. 3. The method for producing modified wood according to claim 2, wherein the catalyst is a quaternary ammonium salt.