JPH0216201B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for dimensional stabilizing treatment of wood,
The purpose is to uniformly stabilize the dimensions of long materials. Wood has disadvantages such as expansion and contraction due to changes in the humidity of the outside air, causing it to warp and crack over time. Impregnation treatment with polyethylene glycol is known as a means of improving the expansion and contraction of wood due to moisture absorption and desorption and stabilizing its dimensions. On the other hand, the present inventors have already disclosed in JP-A-55-25324 that polyoxyalkylene glycol mono(meth)acrylate is effective as a dimensional stabilizer for fiber materials.
However, when the wood is small, it can be easily impregnated and uniformly dimensionally stabilized, but when the fiber direction becomes long, impregnation becomes difficult and it is difficult to uniformly stabilize the size. As a result of intensive research into methods for uniformly stabilizing the dimensions of long wood, the inventors of the present invention found that when wood is impregnated with an aqueous solution of polyoxyalkylene glycol mono(meth)acrylate, if ethylene carbonate or ethylene urea is used in combination, the impregnation will occur. The present inventors have discovered that the properties are uniquely improved, and that even long materials can be given uniform and high dimensional stability, leading to the completion of the present invention. That is, the present invention is based on the general formula (Here, R is a hydrogen atom or a methyl group, m is an integer of 2 to 4, and n is 2 to 20.) An aqueous solution of one or more types of polyoxyalkylene glycol monoacrylate or polyoxyalkylene glycol monomethacrylate represented by The method is characterized in that the wood is impregnated with ethylene carbonate or ethylene urea and then cured to stabilize the dimensions of the wood. The compound of formula (1) can be obtained, for example, by addition polymerizing one or more of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc. to acrylic acid or methacrylic acid. In the present invention, the number of moles of alkylene oxide added to the compound of formula (1) is preferably 2 to 20 moles. In other words, when the number of moles added is less than 2 moles, when cured, it becomes too hard and loses the characteristics inherent to wood, and sufficient dimensional stability cannot be obtained. Furthermore, if the number of moles added exceeds 20 moles, the permeability into wood decreases and sufficient dimensional stability cannot be obtained when hardened. In order to dimensionally stabilize wood with a compound of formula (1),
It is necessary to make an aqueous solution with a concentration of 5 to 90% by weight, depending on the tree species and material. In other words, if the concentration of the compound of formula (1) is less than 5% by weight, the impregnation rate is low and the dimensional stabilization effect is insufficient, and if it exceeds 90% by weight, it is difficult to impregnate uniformly due to the lack of water. However, a uniform dimensional stabilization effect cannot be obtained. Note that a water-soluble organic solvent such as methanol, ethanol, isopropanol, or acetone may be partially used in combination with the aqueous solution of the compound of formula (1) for impregnation. Ethylene carbonate or ethylene urea is used in an amount of 0.01 to 10 parts by weight per 100 parts by weight of the aqueous solution of the compound of formula (1). In other words, even if ethylene carbonate or ethylene urea is used in a small amount, a corresponding combined effect can be obtained, but from a practical standpoint, it is preferably 0.01 part by weight or more, and if more than 10 parts by weight is used, ethylene carbonate or ethylene urea will be removed from the treated material over time. It oozes out and is a practical problem. Methods for impregnating wood with the compound of formula (1) include coating methods, dipping methods, hot/cold bath methods, diffusion methods, end pressure injection methods, and pressure injection methods. In order to achieve uniform impregnation in a short period of time, a reduced pressure impregnation method, which is one of the pressurized injection methods, is preferable. That is, a tank containing wood is kept at a reduced pressure, a treatment liquid is introduced into the tank, the pressure is applied to impregnate the tank, and then the excess treatment liquid is recovered at normal pressure. with ethylene carbonate or ethylene urea
In order to harden the compound of formula (1) in wood impregnated with a mixed aqueous solution of the compound represented by formula (1), there are two methods: thermal polymerization by treating the impregnated wood at a temperature of 50°C or higher, or ionizing radiation. Although it is possible to initiate polymerization and cure by irradiation with electron beams, ultraviolet rays, etc., it is usually preferable to carry out the polymerization using a polymerization initiator such as a peroxide or an azo compound. The polymerization initiator used in this case is preferably a water-soluble one such as persulfate. If necessary, add 1 to 20% by weight of an aqueous solution of preservatives and insecticides, such as pentachlorophenol sodium salt, boric acid, and borax.
May be used together. The wood treated according to the present invention exhibits uniform and high dimensional stability, so it can be used in areas where dimensional stability is required.
For example, it is applied to furniture, building materials, chiyubo-related products, etc. The present invention will be explained below with reference to Examples and Comparative Examples. Note that % in the text indicates weight % unless otherwise specified. Examples 1 to 5 Using the compounds of formula (1) shown in Table 1 alone or as a mixture (each abbreviated as A, B, and C), as shown in Table 2, ethylene carbonate or ethylene urea and the above compound were used. A treatment solution was prepared by mixing with the compound of formula (1). Each treatment solution contained 0.3% by weight of potassium persulfate as a polymerization initiator. Using each treatment liquid, the test materials described below were impregnated, hardened, and dried.

[Sample material]

Agatis square timber (length in the cutting direction 30 mm, radial length 100 mm, length in the fiber direction 300 mm, air dry specific gravity
0.40 to 0.48, water content 9%). [Impregnation with treatment liquid] The test material was placed in an impregnation tank and degassed for 2 hours under a reduced pressure of 30 mmHg or less, then the treatment liquid was added to it to return it to normal pressure, and then it was heated at 5 kg/cm ² for 48 hours. After pressure impregnation, the pressure was returned to normal and excess treatment liquid was collected. [Curing and Drying] The test material impregnated with the treatment liquid was wrapped in aluminum foil and cured by heating at 100°C for 2 hours. After that, remove the aluminum foil and store at 50℃ and 30% relative humidity for 4 days at 80℃.
Dry for 2 days at 30% relative humidity. [Evaluation of uniform impregnability] To evaluate the uniform impregnability of the treated sample material, cut out a wood end test piece to the dimensions shown in the drawing from the impregnation rate and the treated sample material, and then measure the dimensions as it absorbs moisture and dries. This was done by measuring the anti-shrinkage ratio in the tangential direction (hereinafter referred to as ASE). The results are shown in Table 2. Note that the impregnation rate and ASE were each calculated using the following formulas. Impregnation rate = (W ₂ − W ₁ )×R/W ₀ (%) W ₀ : Total dry weight of the sample material before treatment (W ₀ = W ₁ /1.09) W ₁ : Total dry weight of the sample material before treatment Air-dry weight _W2 : Weight of sample material after impregnation and before curing R: Concentration of compound of formula (1) (%) In addition, ASE in Table 2 shall be defined as follows. When the length of the end test piece cut from the treated material in the direction of the cut line when completely dry is L ₂ The length of the end test piece cut out from the treated material in the direction of the cut line when it absorbs water L _{is 1} , the shrinkage rate S is expressed by the following formula. S=L ₁ −L ₂ /L ₂ ×100 (%) The ASE of each end test piece is determined from the shrinkage rate So of the untreated end test piece using the following formula. ASE=So−S/So×100 Comparative Examples 1 to 6 The same test materials used in Examples 1 to 5 were
Examples 1 to 3 except that the treatment liquid shown in the table was used.
This treatment liquid was impregnated according to 5. The impregnated specimens were then dried in the same manner as in Examples 1 to 5 without being cured to obtain treated specimens. The impregnation rate and the change in ASE depending on the distance from the end of the wood were measured according to Examples 1 to 5 for the treated sample materials obtained, and the results are shown in Table 2.

[Table] From the results in Table 2, the method of the present invention has a high impregnation rate with the treatment liquid, and furthermore, because the treatment liquid is uniformly impregnated into the long material, each part of the long material has a high dimensional stabilization effect. It was recognized that it shows.

[Brief explanation of drawings]

The drawing is an explanatory diagram of end test pieces for determining various characteristic values of wood subjected to dimension stabilization treatment according to Examples and Comparative Examples.

Claims (1)

[Claims] 1. General formula (Here, R is a hydrogen atom or a methyl group, m is an integer of 2 to 4, and n is 2 to 20.) or 90
A dimensional stabilization treatment method for wood, which comprises impregnating wood with a treatment solution in which 0.01 to 10 parts by weight of ethylene carbonate or ethylene urea is added to 100 parts by weight of a % aqueous solution, followed by curing. 2. The method for dimensional stabilization of wood according to claim 1, wherein in the general formula (1), R is a hydrogen atom or a methyl group, m is 2, and n is 2 to 20.