JPH03130102A - Treatment of lumber - Google Patents

Abstract

PURPOSE:To enhance hygroscopicity, coating properties and adhesive properties of a dimension stabilizing agent by treating lumber and ligneous material wherein ammonium compd. has been introduced thereinto at the temp. lower than the decomposition point of ammonium compd. CONSTITUTION:One part or all parts of hydrogen of NH4<+> are substituted by hydrocarbon group, etc. A compd. having this substituted HN4<+> is introduced into lumber and ligneous material. At a time of introduction or after introduction, this lumber and ligneous material are treated at the temp. lower than the decomposition point of this ammonium compd. Further the ammonium compd. such as alkyl ammonium salt, amide-bonded ammonium salt, ester-bonded ammonium salt, ether-bonded ammonium salt, hydroxyl ammonium salt, pyridinium salt and amine salt is shown. This ammonium compd. generally shows surface activity by substituting hydrogen of NH4<+> with hydrocarbon group, etc. Water absorption properties and hygroscopicity thereof are lowered in proportion to the degree of hydrophobic property. Thereby the stable dimension stability can be obtained in the whole relative temp. region.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for effectively adsorbing ammonium compounds to wood and essential materials, thereby stabilizing the dimensions of wood and wood materials.

[Problems with conventional technology] PEG (Polyethylene Gly-col) is used as a dimensional stabilizer for wood and wood materials that does not involve chemical reactions.
Non-volatile swelling agents with vapor pressure drop such as NaCl and NaCl are used.

When an aqueous solution of these chemicals is introduced into wood, the vapor pressure of the aqueous solution decreases, so during the dehumidification process, water does not evaporate and the wood shrinks until the relative humidity drops to the vapor pressure of a saturated aqueous solution of the agent. disappears. Therefore, the dimensional stabilizer must have a sufficient vapor pressure drop in its aqueous solution.

Wood treated with these chemicals becomes highly hygroscopic. In addition, when these chemicals have swelling properties in wood, they penetrate into the cell walls through the temporary voids in the cells created by swelling, and in low relative humidity regions, water and these chemicals are adsorbed into the walls. It maintains a swollen state and prevents shrinkage. However, because the adsorption force is small, water is preferentially adsorbed in a high relative humidity region, making it difficult for the drug to be adsorbed, forcing it through the space-time space into the internal cavity and eventually flowing out onto the wood surface.

Wood treated with conventionally used dimensional stabilizers has high hygroscopicity, which reduces the surface texture, and tends to cause poor adhesion and painting due to leakage onto the wood surface. The current situation is that we are forced to use it for specific purposes.

[Problems to be Solved by the Invention] Therefore, in view of the prior art as described above, the present inventor has developed a method for dimensional stabilization that does not change the surface texture of wood or wood materials and does not cause spillage. As a result of intensive research into chemical treatment of wood, we discovered for the first time a completely new wood treatment method that can solve all of these problems and exhibit stable dimensional stability in all relative humidity ranges, leading to the completion of the present invention. It is.

[Means for Solving the Problem] That is, the present invention introduces a compound in which part or all of the hydrogen of NH, ``'' is replaced with a hydrocarbon group, etc., into wood and wood materials, and at the time of or after the introduction, the ammonium compound is This invention relates to a method for treating wood, characterized by treating it at a temperature below its decomposition point.

[Function] The ammonium compound in the present invention refers to ammonium compounds such as alkylammonium salts, amide-bonded ammonium salts, ester-bonded ammonium salts, ether-bonded ammonium salts, hydroxylammonium salts, pyridinium salts, and amine salts. Ammonium compounds generally exhibit surface activity by replacing them with hydrocarbon groups, etc., and their water absorption and hygroscopicity decrease in proportion to the degree of hydrophobicity.When such ammonium compounds are introduced into wood or wood materials, dielectric It is advisable to use a highly polar solvent such as water or a lower alcohol to dissolve the cell wall.This is because the swelling property of the solvent against the cell wall forms temporary voids in the wall, making it easier for the drug to diffuse, and at the same time, the cell wall and This is because the negative charge generated on the cell wall due to the dielectric constant difference between the solvents strongly attracts the cation moiety of the ammonium compound and selectively adsorbs it.

However, sufficient dimensional stability cannot be expected simply by electrostatic adsorption into the cell wall. This is because the cation moiety of the ammonium compound is not effectively oriented to the hydroxyl group in the cell wall. In order to do this, wood and wood materials are exposed to temperatures near or above the glass transition point (thermal softening point) of polymers such as cellulose, hemicellulose, and lignin that make up cell walls, thereby activating the molecular movement of the polymers. This is done by facilitating the migration of ammonium compounds into the polymer.

However, since the thermal softening point of the polymer constituting the cells is high, in order to carry out the process efficiently, it is desirable to lower the PA softening point by intervening a polar substance when raising the temperature.

Since the wood and wood materials obtained in this way have a very high adsorption power for ammonium compounds, they will not be replaced by moisture and there is no risk of them leaking onto the wood surface.

Furthermore, by using an ammonium compound in which the hydrogen is replaced with an appropriate hydrophobic group, it becomes possible to perform treatment without leaving a woody texture with low hygroscopicity even at high temperatures.

In this way, the mechanism of dimensional stabilization using ammonium compounds is completely different from that of conventional dimensional stabilizers, and it is possible to produce treated wood that does not impair the texture, paintability, and bone attachment properties, which were the drawbacks of conventional methods. .

The following are LBDs with heat absorbing properties comparable to wood and wood-based materials.
MAC (Laurylbenzyldin+ethyl
Although the present invention will be explained in Examples using am-monium Chloridel, the present invention is not limited to such Examples.

[Example 1 Treatment liquid A mixture of LBDIC (30 parts), isopropyl alcohol (5 parts), and pure water (65 parts).

Test piece 2 fiber direction 100mm, width 120n+m, thickness 2
5 pieces each of 1IIIn oak, white ash (hereinafter referred to as WA), and beech thin plates were left in a constant temperature FA oven (model DS-45, manufactured by Shimadzu Rika Kikai Co., Ltd.) kept at 105°C for 2 hours. What I did.

Pair of song pieces 2 Five pieces of each dog-sized thin plate IJj of the same size as the test piece of the above test piece at the adjacent part in the fiber direction were used in the same way as the test piece.

Example 1 All 15 of the above test pieces were inserted into a pressure vessel and heated to 50 torr.
After being allowed to stand still for 30 minutes at a pressure of , the treatment liquid was introduced into the pressure vessel, and the inside of the vessel was filled with the chemical solution. Thereafter, the test piece was allowed to stand at a pressure of 10 atm for 2 hours, and the chemical solution was introduced into the test piece. After that, in order to determine the total dimensions and total dry weight of this test piece, the test piece taken out from the pressure vessel was placed in a vacuum dryer (32℃, 2
It was left in Jtorrl for 36 hours to make an omnipotent test piece.

The 15 test pieces thus made were heated to 50°C.

95%RH+;: Constant temperature and humidity chamber (ADVANTEC
Made.

^E-204) for 3 days and nights, then vacuum drying with fsc
The sample was left at m < 4o C and 24 torrl for 19 hours to be used as an omnipotent test piece again.

At this time, the average of the width dimension increase rate and weight increase rate of the omnipotent specimen after drug injection (condition 1) and the omnipotent specimen after being left in a constant temperature incubator (condition 2) compared to the omnipotent specimen before drug injection. The values were as follows.

Example 2 After producing omnipotent test pieces for each tree species into which the treatment solution was introduced in the same manner as in Example 1, they were placed in a constant temperature incubator (35°C) together with a dry control piece (Net-92%RHf24hr).
, Dry-60% rlH + 24 hrl repeated dry-wet test was conducted to determine dimensional stability (ASEI and anti-hygroscopic ability).
MEEI was evaluated.

Table 2- Table 2-2 By the way, each 14f+ in Table 2! The weight increase rates during gold drying after injection of the treatment liquid were 47.8% for Buna, 38.7% for Nara, and 23.8% for WA.

In addition, the dimensional stability and anti-moisture absorption ability are calculated using the following formula (% formula) () After this, the temperature of the thermostatic chamber was further increased to 50°C, and the net
-95% old 1 f24hr), Dry-60%n+
Table 3 shows the results of a 1f24hrl dry temperature repeated test.

Table 3-1 Table 3-2 Example 1 shows that sufficient adsorption to hydroxyl groups is not achieved only by injecting the treatment liquid at room temperature. Moisture content 20
The thermal softening points of hemicellulose and lignin are said to be 54 to 142'C and 72 to 128C, respectively, and the softening point decreases by 50 to 100C in the presence of a highly polar substance such as water. In the case of wood, when the elastic modulus of omnipotent wood at 0°C is taken as 100%, the elastic modulus of wood swollen with water is 53% at 0°C, 50% at 20°C, 40% at 50°C, and 40% at 70°C.
It is said that the temperature decreases to 30% at about 50°C, which is around the thermal softening point of hemicellulose, and the intermolecular bonds between the polymers that make up the wood are weakened. i.e. 50℃
The reason why the degree of swelling of wood that has been injected with chemicals changes rapidly when it is left in high humidity conditions is because the bonds between molecules are further weakened, making it easier for the chemicals to move and increasing the amount of orientation toward hydroxyl groups. It seems to be.

Example 2 shows how the dimensional stability of wood injected with a chemical solution changes rapidly when the temperature reaches about 50°C. Moreover, the anti-hygroscopic ability also increases when the temperature reaches 50°C. This means that the moisture absorption rate of LBDMAC at 50℃, 95% RH and 60% RH is 45% and 14.5% respectively, and that of wood is about 22% and 9.5% respectively, and the hygroscopicity of the chemical is higher than that of wood. As can be seen from the fact that the wood into which the chemical has been introduced has a hygroscopicity lower than that of untreated wood, the adsorption of the chemical to the hydroxyl groups causes water to be absorbed by the chemical and the hydroxyl groups. As mentioned in 1iii, as the temperature increases, the orientation of this drug to the hydroxyl group becomes more advanced, improving the dimensional stability and anti-hygroscopic ability.6 [Invention [Effect] As described above, the present invention effectively adsorbs ammonium compounds to wood and wood materials, thereby improving the heat absorbing properties of dimensional stabilizers, which have been problems in the past, and improving paintability and paintability due to spillage. This invention is expected to provide high dimensional stability while solving problems such as poor adhesion, and is believed to be an epoch-making invention that will lead to the future of wood dimensional stabilization methods.

Claims (1)

[Claims] A method for treating wood, which comprises treating wood and wood materials into which an ammonium compound has been introduced at a temperature below the decomposition point of the ammonium compound.