JPS62160201A - Improved treatment method of woody material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a method for modifying wood materials, which can improve dimensional stability by imparting water resistance and moisture resistance to wood materials. .

(Prior art and its problems) Conventionally, as a method for modifying wood materials, so-called W2C conversion, in which synthetic resin liquid is injected into wood materials and hardened, has been known. Because of the use of hydrophilic wood materials, there is little penetration of the synthetic resin liquid into the wood cell walls, making it impossible to impart sufficient water and moisture resistance.

For this reason, as described in JP-A No. 55-25324, a method was developed in which a water-soluble compound such as polyethylene glycol methacrylate is impregnated or applied to a wood material and then hardened. There was a problem in that the crosslinks between the wood materials were weak and they easily melted when repeatedly immersed in water, reducing the effect of modifying the wood material by half.

The present invention provides a method for modifying wood materials that solves these problems.

(Means for Solving the Problems) In order to achieve the above object, the method for modifying wood materials according to the present invention comprises combining polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate and N-hydroxymethyl monoacrylate. Wood material is impregnated with a treatment solution prepared by mixing saturated amide or N,N-dihydroxymethyl unsaturated amide with a building agent at a molar ratio of 0.1 to 9 and adjusting the concentration to 10 to 70% by weight with a polar solvent. The wood material is characterized by being heated and hardened, and the mixture is bonded to each other within the wood material, and the hydroxyl groups in the wood component and the mixture are etherified to modify the wood material.

That is, N-hydroxymethyl unsaturated amide such as N-methylol acrylamide or N,N-dihydroxymethyl unsaturated amide is itself three-dimensionally crosslinked and copolymerized with polyethylene glycol methacrylate etc. It is presumed that the wood material is modified by an etherification reaction with hydroxyl groups.

In the method of the present invention, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate or monomethacrylate is used as the polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate.

In addition, as the N-hydroxymethyl unsaturated amide or NN-dihydroxymethyl unsaturated amide, acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, or methacrylic acid such as N-methylolacrylamide, N,N-dimethylolacrylamide, etc. These include N-methylol derivatives and N,N-dimethylol derivatives of acid dimer amides that are soluble in polar solvents.

The mixing ratio of polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate and N-hydroxymethyl unsaturated amide or N,N-dihydroxymethyl unsaturated amide is 0.1 to 9 in molar ratio, preferably 0. .5 to 4, and if this molar ratio is less than 0.1, sufficient water resistance will not be exhibited even if these solutions are impregnated into wood materials and cured, and if the molar ratio is 9 or more, The treated wood turns yellow and loses its flexibility, resulting in a significant decrease in strength.

As a crosslinking agent, a water-soluble radical reaction initiator such as a persulfate such as potassium persulfate or a hydroperoxide as a polymerization initiator for double bonds is used for polyoxylene glycol monoacrylate or polyoxylene glycol monomethacrylate. .005 to 1.0% by weight, and acidic catalysts such as condensation catalysts such as sodium bisulfate, ammonium chloride, mineral acid salts of amines, p-toluenesulfonic acid, oxalic acid, and butyric acid as crosslinking agents for methylol groups. It is used in an amount of 1 to 10% by weight based on the methyl unsaturated amide or N,N-dihydroxymethyl unsaturated amide.

This crosslinking agent is used together with the polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate and N-hydroxymethyl unsaturated amide or N,N-dihydroxymethyl unsaturated amide,
It is mixed with a polar solvent that swells wood, such as water or a lower alcohol, to form a polar solution. At this time, if the concentration of the polar solution is less than 10% by weight, the amount of filling into the wood material will be small and it will not work as expected. If it exceeds 70% by weight, the swelling of the wood material will be small and it will be difficult to uniformly impregnate the wood material.
~70% by weight, preferably 20-50% by weight.

In addition to wood veneers and wood fiberboards, cellulosic materials such as cotton and paper can also be used as wood materials that can be modified by impregnating them with polar solutions. Depending on the degree of penetration, methods such as application with a brush, dipping, reduced pressure, and pressurized injection may be used.

The impregnation rate of the polar solution into the wood material is 20-100% (
Solid content), and after impregnating, polymerization and hardening are carried out by hot pressure using a press or hot air at a temperature of 80 to 160°C.

(Function) ゛N-Hydroxymethyl unsaturated amides, etc. themselves undergo three-dimensional condensation polymerization of their methylol groups, so they do not easily leach out even if they absorb water, and polyoxyalkylenes, which easily leach out in water, Glycol monoacrylate etc. copolymerize with vinyl groups such as N-hydroxymethyl unsaturated amide in the wood material, and furthermore, hydroxyl groups such as polyoxyalkylene glycol monoacrylate and methylol groups such as N-hydroxymethyl unsaturated amide form ethers. Because it undergoes a chemical reaction, it firmly adheres within the wood.

Furthermore, since the treatment liquid of the present invention has polarity, it swells the wood material and brings the above-mentioned reactant into contact with the wood component. It undergoes a chemical reaction, making it difficult to adsorb external moisture, making it water and moisture resistant, and improving the dimensional stability of the wood material.

(Example) Next, examples of the present invention and comparative examples will be shown.

Example N - 100 parts by weight of methylol acrylamide and polyethylene glycol methacrylate (molecular weight 170-180)
) and 5 parts by weight of ammonium chloride were mixed in advance, and this mixture was diluted with a 0.5% potassium persulfate aqueous solution (polymerization initiator) to give a 30% concentration aqueous solution.

This aqueous solution was impregnated into an air-dried veneer with a moisture content of 10% by a vacuum and pressurization method, and then cured with hot air at 100° C. for 3 hours.

The modified wood thus obtained is designated as A.

Comparative Example 1 An air-dried veneer with a moisture content of 10% was impregnated with the aqueous solution and cured under the same conditions using an aqueous solution having the same concentration as in the above Example except for N-methylolacrylamide and ammonium chloride. Ta.

The modified wood thus obtained is designated as B.

Comparative Example 2 An air-dried veneer with a moisture content of 10% was impregnated with the aqueous solution and cured under the same conditions using an aqueous solution having the same concentration as in the above Example except for polyethylene glycol methacrylate.

The modified wood thus obtained is designated as C.

Modified wood A and B obtained in the above Examples and Comparative Examples
, C's weight increase rate, anti-swelling rate, anti-shrinkage rate, and dissolution rate are shown below.

The shrinkage rate and elution rate were calculated using the following formulas.

(weight increase rate) W, -Wo -X 100 O However, Wo: absolute dry weight of air-dried veneer before aqueous solution impregnation treatment.

Wl: Bone dry weight after treatment (anti-swelling coefficient) Indicates the length of bone dry treated materials, each of which has 10 fins and 11
g for 30 minutes, return to normal pressure, absorb water, and leave to soak at room temperature for 1 week to absorb water, each length L3.4
shall be.

(Anti-shrinkage rate) Let L2 be the length of the filling material, and L2 be the length of the treated material.

(elution rate) 1.-Expletive X 100 The absolute dry weight after treatment at the above anti-shrinkage rate is defined as W2.

As is clear from the above table, the modified wood impregnated and cured only with polyethylene glycol methacrylate of Comparative Example 1 showed a large amount of leaching during one water absorption or immersion in water, and the N-methylol of Comparative Example 2 Modified wood impregnated with only acrylamide and cured had low initial dimensional stability, yellowing, drying cracks, and brittleness of the wood.

In contrast, the modified wood according to the embodiment of the present invention was treated with
There is no g-liquid elution, excellent dimensional stability, and less yellowing and brittleness of the material.

(Effects of the Invention) As described above, according to the wood material modification method of the present invention, polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate and N-hydroxymethyl unsaturated amide or N,N −
and dihydroxymethyl unsaturated amide in a molar ratio of 0.1 to 9.
Mix with a crosslinking agent at a ratio of
Since the wood material is impregnated with the treatment solution adjusted to 70% by weight, the polar solvent allows the modification solution to sufficiently penetrate into the cell walls of the wood material, and also allows the modification solution to penetrate into the cell walls of the wood material with the polar solvent. are strongly bonded together to prevent the modification solution from leaching even after repeated water absorption, and can be modified into a wood material that exhibits good dimensional stability over a long period of time.

Furthermore, there is little yellowing or brittleness of the wood material, and excellent modification is possible without impairing the properties of the wood material itself.

Claims (1)

[Claims] Mixing polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate and N-hydroxymethyl unsaturated amide or N,N-dihydroxymethyl unsaturated amide together with a crosslinking agent at a molar ratio of 0.1 to 9, Concentration 10-70 in polar solvent
A method for modifying a wood material, which comprises impregnating the wood material with a treatment liquid adjusted to a weight percent and curing it by heating.