JPH06344308A - Production of resin treated wooden material - Google Patents

Abstract

PURPOSE:To produce a resin treated wooden material excellent in dimensional stability, durability, antistaining properties and rotproof and mothproof properties with good productivity. CONSTITUTION:A wooden material is impregnated with an aq. phenol resin soln. mixed with a proper amt. of an acid such as toluenesulfonic acid or benzenesulfonic acid and adjusted to 40% or less in resin content. At this time, the aq. phenol resin soln. is easily infiltrated into the cell walls of the wooden material by the presence of a large quantity of water. Subsequently, the impregnated wooden material is heated to temp. insulfficient to cure a phenol resin not only to evaporate the moisture in the cells of the wooden material but also to increase the viscosity of the aq. phenol resin soln. to eliminate the outflow of the resin from the wooden material and, in this state, the wooden material is inserted in a hot press to efficiently produce a resin treated wooden material generating no strain or warpage. Further, by preliminarily adjusting the impregnation amt. of the phenol resin to the wooden material to 15% by wt. of the wooden material, the resin treated wooden material excellent in dimensional stability and rotproof and mothproof properties is obtained.

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 a resin-treated wood material having excellent dimensional stability, durability, stain resistance, and antiseptic / insect resistance.

[0002]

2. Description of the Related Art Conventionally, a modified phenol has been prepared by injecting and filling a phenol resin solution into a minute void in the cell wall of a wood material to improve the dimensional stability and strength, which are the disadvantages of the wood material. A resin-injection treated wood material is known. In such a resin-treated wood material manufacturing method, if the resin is injected and hardened even in a large void portion such as the wood cell inner cavity, the machinability, which is a characteristic of the wood material, is reduced and the weight reduction is impaired. In addition, darkening and weakening will occur.

For this reason, the inventors of the present invention disclosed in Japanese Patent Laid-Open No. 4-2
As described in Japanese Patent No. 78302, the nonvolatile content is 40%.
% Or less and impregnate a wood material with an aqueous phenol resin solution obtained by adding an appropriate amount of acid, and volatilizing the water in the wood material to hollow the inside of the cell lumen and increase the phenol resin aqueous solution. We developed a method in which the resin is made to be viscous and left in a small void in the cell wall to be in a state, and then the impregnated resin is cured by heating with hot air.

[0004]

However, according to the above-mentioned method for producing a phenol resin-injection-treated wood material, the wood material impregnated with the phenol resin aqueous solution is heated while being left in a high temperature by a hot air dryer or the like. Since the impregnated resin is hardened, the material undergoes deformation such as distortion and warpage as the resin hardens, and heating with hot air requires a longer time to harden the impregnated resin, resulting in increased productivity. There is a problem that it decreases.

Further, the amount of the phenol resin impregnated with respect to the weight of the wood material is also indefinite depending on the variation of the water content of the wood, and therefore the dimensional stability varies, and a homogeneous resin-treated wood material cannot be obtained. There is a problem. The present invention has been made in view of such problems, and maintains the original appearance of wood despite the impregnation treatment with a phenol resin, and has dimensional stability, durability, stain resistance, antiseptic and insecticidal properties, etc. The present invention provides a method for producing a resin-treated wood material capable of efficiently obtaining a resin-treated wood material exhibiting comprehensively excellent physical properties.

[0006]

In order to achieve the above object, the method for producing a resin-treated wood material of the present invention has a water content of 15%.
The wood material adjusted to the following is impregnated with an aqueous phenol resin solution with a resin content of 40% or less obtained by adding an appropriate amount of acid, and then, in the wood material at a temperature at which the impregnated phenol resin is not cured. After the water content is dried to a predetermined amount or less, the wood material is inserted into a hot press and the resin is hardened by hot pressing. In such a method for producing a resin-treated wood material, it is desirable that the impregnated amount of the phenol resin is 15% or more of the weight of the wood material in terms of solid content, as described in claim 2. As described in No. 3, the hot pressing conditions by hot pressing are
It is preferable that the pressure is 80 to 140 ° C. and the pressure is 1 to ² kg / cm ² .

[0007]

[Function] Since the non-volatile content of the phenol resin aqueous solution is adjusted to 40% or less, the condensation polymerization reaction of the resin is suppressed by the water content of the aqueous solution, and the pot life of the resin aqueous solution can be improved and its viscosity is increased. The aqueous phenol resin solution easily penetrates into the cell walls of a wood material which is prevented from being hydrophilic. At this time, the water content of the wood material should be 15 in advance.
%, The impregnation is performed more smoothly. Next, the wood material impregnated with the aqueous phenol resin solution dries and dissipates the moisture in the wood at a temperature that does not cure before the impregnating resin is cured, so most of the water is released from the wood material. As a result, a void is formed in the cell lumen and the acid reacts with the resin as the water content decreases, and the resin liquid becomes highly viscous and remains in the wood without flowing out.

Then, when the wood material is inserted into a hot press and hot pressed, heat is efficiently transferred and the wood material is impregnated into the wood material while preventing warping and twisting by the hot platen. The resin-treated wood material, which is cured in a short time and has no dimensional stability even after curing, can be efficiently produced. In addition, the amount of the impregnated phenolic resin is calculated as 15% of the weight of wood based on the solid content.
%, It is possible to mass-produce a homogeneous resin-treated wood material with excellent antiseptic and dimensional stability. By setting the temperature at 1 ° C and the pressure to 1 to ² kg / cm ² , it is possible to prevent the coloring of wood materials from coloring components, the darkening of phenol resin, the dry cracking of the surface, the occurrence of puncture, etc. It is possible to obtain a treated wood material.

[0009]

EXAMPLES Next, the examples of the present invention will be described in detail. To a wood material, an appropriate amount of acid was added to a phenol resin aqueous solution whose resin content was adjusted to a concentration of 40% or less by adding an appropriate amount of water. A treatment liquid for impregnation is prepared. in this way,
Since the resin content of the phenolic resin aqueous solution is adjusted to 40% or less, the polycondensation of the phenolic resin is suppressed by the large amount of water even in the presence of acid, and the pot life of the treatment liquid can be extended and the wood material The impregnation becomes easy when impregnating the treatment liquid. As the acid, an acid such as toluene sulfonic acid, benzene sulfonic acid, phenol sulfonic acid, xylene sulfonic acid, oxalic acid, boric acid or phosphoric acid can be used.

Next, this treatment liquid is impregnated into a wood material. As the impregnation method, a pressure reduction method, a pressure method, or a pressure reduction pressure injection method is used. Further, the wood material impregnated with the treatment liquid may be a thick lumber product such as a lumber or a plate material or a hollow material, a laminated wood, a plywood or a thin plate such as a veneer, and its tree species is not particularly limited. However, the material whose water content is adjusted to 15% or less is used. Specifically, the water content is adjusted to 10% or less for plywood and veneer, and 15% or less for sawn timber. The lower the water content, the easier the impregnation with the treatment liquid.However, if the water content is too low, not only will it take a long time to dry the wood until the water content becomes low, but the wood will also warp or crack. Is not preferable. Also, the water content is 15%
In the above wood material, it takes a long time to impregnate the treatment liquid, and the impregnation of the treatment liquid tends to vary depending on the variation of the water content in the material.

When the wood material is impregnated with the treatment liquid using the impregnation means as described above, a large amount of water is present in the phenol resin aqueous solution. The increase in the viscosity of the acid and the phenol resin is suppressed, the pot life of the treatment liquid is prolonged, and the treatment liquid easily penetrates into the cell walls of the hydrophilic wood material.

The treatment liquid is impregnated so that the amount of the phenol resin impregnated into the wood material is 15% or more of the weight of the wood material in terms of solid content. The reason is that the anti-swelling (contraction) ability (hereinafter referred to as ASE) can be cited as one example of evaluating the dimensional stability of a resin-impregnated wood material.
This ASE is (volume swell (shrinkage) rate of untreated material-volume swell (shrinkage) rate of treated material) / volume swell (shrinkage) of untreated material)
This is because the higher the rate is shown by the rate x 100, the better the dimensional stability.

The inventors of the present invention have conducted an experiment on the relationship between the weight increase rate of wood materials by impregnation with a phenol resin and ASE with wood materials of various tree species, but there are some changes depending on the tree species. It was confirmed that the relationship shown in 1 occurred. That is, as is clear from this diagram, the weight increase rate of the resin-impregnated and hardened wood material is
If the amount of phenolic resin impregnated is adjusted to 15% or more, ASE will increase to 50% or more, and even if it exceeds this, ASE will increase only to 60%, and resin impregnated wood with good dimensional stability. The material is obtained. Further, by increasing the amount of impregnated phenol resin, it is possible to impart excellent corrosion resistance and insect resistance to the wood material specified in JIS A9201.

Next, the wood material impregnated with the treatment liquid as described above is once dried at a temperature at which the impregnated phenol resin is not cured. At this time, if the drying temperature is a high temperature such as that of a hot air dryer, the impregnating resin is accelerated to be hardened, and the evaporation of water from the wood material is biased to cause cracking or deformation of the material, which is not preferable. Therefore, as described above, the resin is dried at a relatively low temperature such as vacuum drying where the resin does not harden, and as a result, most of the water in the material is diffused to the outside to form voids in the cell lumen, As the water content decreases, the acid reacts with the phenol resin aqueous solution to become highly viscous, and there is no risk of it flowing out from the wood material. The degree of drying is 15 to 25% in terms of water content.

The wood material impregnated with the treatment liquid in such a state is then inserted into a hot press and hot pressed by the hot platen to cure the impregnated resin to obtain a resin-treated wood material. At this time, if the heating temperature by hot pressing exceeds 140 ° C, coloring is caused by the coloring component of the wood material and the phenol resin is darkened to impair the appearance, and further, drying cracks occur on the surface, which is not preferable. Temperature is 80 ℃
In the following, since it takes a long time to cure the impregnated resin and the productivity is lowered, the impregnated resin is heated at a temperature of 80 to 140 ° C, preferably 100 to 120 ° C.

On the other hand, the higher the pressure of the hot press is, the more effectively the impregnating resin is effective, but on the other hand, the thickness is reduced, the product has a high specific gravity, and there is a high possibility that the residual water vaporizes to cause a flat tire. Therefore, it is desirable to carry out the pressure within the range of 1 to ² kg / cm ² , and the pressing time is suitably 3 to 4 minutes per mm. In this way, since the wood material impregnated with the phenol resin solution is hot pressed by the hot press, not only is heat transferred directly to the wood material and thermal efficiency is good, but also the curing time of the impregnated resin is shortened and the manufacturing efficiency is improved. Improved and on top of that
Since it is heat-pressed while being sandwiched between hot plates, the occurrence of warpage and twist due to dry hardening of the resin-impregnated wood material is suppressed, and a resin-impregnated hardened wood material that does not deform even after hardening is obtained. be able to.

Next, Table 1 shows the results of the decay resistance test of the resin-impregnated wood material (resin impregnation rate 16%) and the untreated wood material obtained as described above.

[0018]

[Table 1]

[0019]

[Table 2]

The above-mentioned decay resistance test was carried out by using brown rot fungus Pleurotus ostreatus and white rot fungus Kawaratake as test bacteria in accordance with JIS Z2119 and the Japanese Wood Preservation Association No. 3-1979 test method. It was For weather resistance operation, soak the specimen in water at about 10 times the room temperature (about 25 ℃) for 8 hours with stirring, and then in a dryer at about 40 ℃.
The operation of drying for 16 hours was repeated 10 times. As test specimens, 9 pieces of beech wood having a size of 2 × 2 cm and a thickness of 1 cm were used. As is clear from this table, the resin impregnated wood material of the present invention has an extremely small weight reduction rate and is excellent in decay resistance.

Next, Table 3 shows the results of the field test of the phenol resin-impregnated wood material of the present invention and the untreated wood material.
As these test pieces, a 3 x 3 x 35 cm piece of hemlock was used, and a test was carried out by burying it in the soil in accordance with the Japan Wood Preservation Association Standard No. 11. As a result, the resin-impregnated woody material of the present invention showed almost no change in the color of its surface and no decay was observed, even though it was buried in the soil for three years outdoors.

[0022]

[Table 3]

[0023]

As described above, according to the method for producing a resin-treated wood material of the present invention, a wood material having a water content adjusted to 15% or less has a resin content of 40% or less obtained by adding an appropriate amount of acid. After impregnating the phenolic resin aqueous solution, and then drying the impregnated phenolic resin so that the water content in the wood is reduced to a predetermined amount or less at a temperature at which the phenol resin impregnated is not cured, then insert the wood into a hot press. However, the resin is characterized by being cured by heat and pressure, and since the phenol resin aqueous solution is adjusted to have a nonvolatile content of 40% or less, it is possible to suppress the condensation polymerization reaction of the resin by the water content in the aqueous solution. Along with improving the pot life of the resin aqueous solution, it is possible to prevent an increase in the viscosity of the resin solution and easily penetrate into the hydrophilic cell walls of the wood, and moreover, the water content of the wood in advance, Adjust to 15% or less Since it is, it is possible that the impregnation is carried out more smoothly by shortening the resin impregnation time.

Further, since the wood material impregnated with the phenol resin aqueous solution dries and dissipates the moisture in the wood material at a temperature at which it is not cured before the impregnating resin is cured, most of the wood material is removed. It is possible to release water and form a cell lumen in the void, and the acid reacts with the resin as the water content decreases, and the resin liquid becomes highly viscous and flows into the wood without flowing out. It can remain. Therefore, it is possible to improve the machinability of the resin-treated wood material obtained by the voids of the cells and to reduce the weight thereof, and moreover, the curing treatment of the resin liquid remaining in the material is promptly performed. You can do it.

Further, since the hardening treatment is carried out by hot pressing by hot pressing, the heat transfer is directly carried out to the resin-impregnated wood material and the heat efficiency is good, and the resin liquid impregnated in the wood material is Compared with the previous application example, it can be cured in a short time of 1/4 and productivity is improved.
It is possible to obtain a resin-treated wood material in which warp or twist is prevented from being generated in the wood material by the hot plate of the hot press and the resin material does not deform even after curing.

Further, by adjusting the impregnation amount of the phenol resin to 15% or more of the weight of the wood material in terms of the solid content in advance, a large amount of the homogeneous resin-treated wood material excellent in antiseptic and dimensional stability can be obtained. Production is possible, and in addition, the hot press conditions by the hot press are temperature 80-140 ℃, pressure 1-2.
By setting it to Kg / cm ² , it is possible to obtain a resin-treated wood material that is excellent in appearance while preventing coloring due to the coloring components of the wood material, darkening of the phenol resin, surface dry cracking, puncture, etc. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the anti-swelling (shrinkage) ability of a resin-treated wood material and the weight increase rate due to an impregnated resin.

Claims (3)

[Claims] 1. A wood material having a water content adjusted to 15% or less,
Impregnate an aqueous solution of phenol resin with a resin content of 40% or less by adding an appropriate amount of acid, and then reduce the water content in the wood material to a predetermined amount or less at a temperature at which the impregnated phenol resin is not cured After the drying, the wood material is inserted into a hot press, and the resin is hardened by heat and pressure, and a method for producing a resin-treated wood material. 2. The amount of impregnated phenolic resin is 15% or more of the weight of wood material in terms of solid content.
A method for producing a resin-treated wood material as described. 3. The hot-pressing condition by hot pressing is a temperature of 80-
The method for producing a resin-treated wood material according to claim 1 or 2, wherein the temperature is 140 ° C and the pressure is 1 to ² kg / cm ² .