JPH05111904A - Manufacture of synthetic resin impregnated woody material - Google Patents

Abstract

PURPOSE:To carry out an impregnating/curing process to a woody material having little difference of shade of colors and void volume between a spring material and a summer material in a manner that the appearance shows the state in which the grain pattern remains as it is. CONSTITUTION:First, a woody material is impregnated and cured with resin liquid such as phenol resin or the like in a manner of leaving spaces such as cellular lumens or the like of a woody material to increase compression strength of the woody material, and then transparent addition polymerization type resin liquid is injected into spaces. At that time, the injection amount of addition polymerization type resin liquid is limited and reduced by thermosetting resin impregnated and cured on cell walls, and also impregnated evenly all over. When the woody material is thermoset and cured in said state, the woody material is not turned into transparent and thickened and shows the appearance in which the tone of grains leaves as it is.

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 synthetic resin-injected wood material which has improved physical properties such as desired hardness, scratch resistance and durability without substantially changing the original wood grain pattern.

[0002]

2. Description of the Related Art Conventionally, a wooden material is injected with a synthetic resin liquid,
The so-called modified hardness, scratch resistance, durability, etc.
A resin-injected wood material called WPC is known.
In order to produce such a resin-injection-treated wood material, an addition polymerization type resin liquid such as acrylic resin, styrene, or polyester resin is injected and filled in the voids in the wood material, and then radical polymerization is performed by heat or radiation. The method of hardening is adopted.

[0003]

However, if such a resin injection treatment method is applied to tree species such as cypress, spruce, and spruce, which have little difference in color between spring wood and summer wood, the whole is transparent and dense. When it is colored, it has an oil-paper-like appearance, and when it is used for tree species with large voids in the spring timber, such as pine and hemlock, the resin filling rate of the spring timber increases and the color becomes transparent and dark. However, there was a problem that the color tone of the wood grain was reversed and the color tone of the wood material was lost.

The reason why the whole wood material becomes dark and transparent in this way is that when the resin is filled in the voids of the wood material and the refractive index of light changes and the resin liquid injected into the wood material is hot pressed, Compared to dry wood, the wood material is more likely to be compressed and deformed due to wetting with resin liquid and heating at the time of hot pressing, and the resin injected in the compressed and hardened state is hardened, so that it becomes consolidated and the filling rate becomes high, resulting in transparency. It is thought that this will increase. In addition, the color tone of the grain is reversed because the resin liquid is selectively injected into the spring wood part with large wood voids,
It is presumed that, similarly to the above, a large amount of compressive deformation occurs in a portion having a large void at the time of hot pressing, and the resin is excessively filled and fixed. If the degree of heat and pressure is weakened or the material is heated and hardened in an oven, unevenness in hardening of the injected resin and uneven distribution of the resin occur, which causes problems in product stability and productivity.

Therefore, as described in Japanese Examined Patent Publication No. 62-1820, a wood material is impregnated with a thermosetting resin to which a non-copolymerizable low boiling point solvent is added, and the solvent is volatilized at the time of hot pressing. There is a thing to disperse the light by making air bubbles in the resin by doing so, but in the resin injection processing of such wood material, the whole is whitened and the color tone of the wood material is lost. , Uneven distribution of air bubbles depending on the curing method, curing failure due to the components of the wood material, etc.
There is a problem that adjustment during manufacturing is difficult.

The present invention has been made in view of the above problems, and in the conventional resin injection treatment method, the entire grain of the original wood material is not transparent to the tree species in which the whole is transparent or the color tone of the grain pattern is reversed. It is intended to provide a method for producing a synthetic resin-injected wood material, which is intended to perform a resin injection treatment so as to exhibit a color tone.

[0007]

In order to achieve the above object, a method for producing a synthetic resin-injected wood material according to the present invention comprises a wood material with little lightness between spring wood and summer wood, or a space between spring wood and summer wood. The wood-based material that has a large difference in porosity is impregnated with a thermosetting resin liquid such as phenol resin so that large voids such as the cell lumen of the wood-based material remain, and is then cured. It is characterized in that a resin liquid is filled in the above-mentioned voids and is heated and pressed to be cured.

[0008]

[Function] Since the thermosetting resin liquid is injected and cured before the addition polymerization type resin liquid is injected into the wood material, the thermosetting resin is cured while being filled in the cell wall which is the substantial part of the wood material. The compressive strength of the wood material is improved, and the impregnation of the addition polymerization type resin liquid to be injected next is reduced so that the excess addition polymerization resin liquid is not partially injected into the wood material and Liquid injection volume is reduced. Therefore, the wood material does not become transparent and dark as a whole, and the wood grain has an appearance in which the color tone remains as it is, and the resin-injection-treated wood material with improved hardness, scratch resistance, and durability can be obtained. ..

[0009]

EXAMPLES Next, the examples of the present invention will be described in detail. A heat content adjusted to a concentration of non-volatile components of 50% by weight or less, preferably 5 to 20% by weight by adding an appropriate amount of a solvent such as water or alcohol. The curable resin liquid is added to the water content below the fiber saturation point (50
Pour into undried wood with a water content of about%). In addition, as the thermosetting resin referred to here, in addition to polycondensation type resins such as phenol, melamine, and urea, resins such as epoxy resin, acrylic resin, and urethane resin, which are less likely to soften at the time of hot pressing described later, are used. To tell.

The resin solution is injected into the wood material by the depressurization and pressure injection methods, but it may also be applied by the dipping or diffusion method so that the resin solution is uniformly injected and impregnated into the wood material. The shape and size of the material, the permeability, the method and conditions suitable for the tree species may be appropriately selected. Further, as the thermosetting resin liquid to be injected, a low molecular weight resin having a molecular weight of 200 or less is preferably used in order to easily permeate the wood material into the cell wall.

On the other hand, the wood material to be injected is preferably a thin plate such as a veneer, and its tree species include coniferous trees such as cypress, pine, hemlock, and spruce, and even broadleaf trees such as spring wood and summer wood. It is applied to materials with little difference in lightness and darkness, and Nanyo wood with large resin liquid permeability with large voids in the spring material.

When the thermosetting resin liquid is injected into the wood material using the appropriate injection means as described above, when the thermosetting resin liquid is a hydrophilic resin liquid such as phenol resin, The treatment liquid easily penetrates into the cell walls of wood.

After injecting the thermosetting resin liquid into the wood material in this way, the resin-injected wood material is heated and dried by high frequency under reduced pressure while paying attention to the occurrence of warpage and cracks, and the thermosetting resin impregnated into the wood material is cured. Volatilize and eliminate the solvent, etc. in the liquid crystalline resin. A hot air dryer may be used as the heating and drying means.

When the solvent such as alcohol in the thermosetting resin liquid is volatilized in this manner, most of the solvent is mainly released from the large voids such as the cell lumen of the wood material to the outside of the material, and the resin is not filled. While a void (cell lumen) is formed, the resin remains in a state of being sealed on the wall surface of the cell wall or filled in a small void in the wall. Such heating and drying treatment is carried out at a temperature of 80 to 160 ° C. for several minutes to several hours depending on the type of resin.

When the weight increase rate of the wood material after the thermosetting resin is injected and cured is 5 to 40%, preferably 10 to 25%,
While maintaining the presence of voids such as cell lumens in the wood material, the cell surface is sealed and the resin is sufficiently injected and cured into the cell wall.

In this case, if the resin filling rate in the voids of the wood material becomes high, the resin may cause coloring and cost increase.
The concentration is adjusted within the range of 50% by weight or less.

Thus, when the thermosetting resin liquid is injected and cured into the cell walls of the wood material, the impregnation of the addition polymerization resin liquid to be injected next is reduced and the compressive strength of the wood material is improved. This compressive strength varies depending on the type of wood material, wood removal, and the coarse density of the wood grain, but when the wood grain surface or the grain surface is pressed, the compression proportional limit is 5 to 50 kg / cm ² =, which will be described later. The hot pressing condition may be selected according to the compression proportional limit.

After the above resin solution is injected into the cell wall of the wood material and hardened, the addition polymerization type resin solution is filled into the hollow space formed by removing the solvent in the wood material and cured. At this time, since the thermosetting resin has been injected and hardened in the cell wall portion of the wood material in the pretreatment, the overall injection amount of the addition polymerization type resin liquid is reduced and the excessive resin liquid is not injected. ..

In this filling and curing step, the above-mentioned thermosetting resin injection-hardening wood material is mainly added to a transparent resin liquid containing a hydrophobic addition polymerizable monomer alone or a hydrophobic addition polymerizable prepolymer as a main component. Or the resin solution is applied to the treated wood material and injected. This operation can be performed under reduced pressure or under pressure.

Examples of the hydrophobic addition-polymerizable monomer used in this step include styrene monomer, methyl methacrylate, styrene oxide, epichlorohydrin and divinylbenzene.

Examples of addition-polymerizable prepolymers include vinyl polymerization acrylates, melamine polymerization acrylic prepolymers, unsaturated polyester prepolymers, acrylic urethane prepolymers, and epoxy prepolymers. A reaction initiator, a plasticizer, a colorant and / or a flame retardant may be added to the addition polymerization type resin liquid.

The treated wood material impregnated with the addition polymerization type resin liquid by the above method is cured in the next step. In this curing step, if necessary, the wood material is pressed and heated by a hot platen press under the conditions of 80 to 250 ° C. and 5 to 50 kg / cm ² =. At the time of this heat and pressure, since the cell walls of the wood material are filled and cured with the thermosetting resin in advance, the cell wall, which is the substantial part of the wood material, is less likely to be softened and hardened in a large deformed state. In addition, as described above, since the injection amount of the addition polymerization type resin liquid is limited as described above, there is no excessive transparency darkening in the wood material, and the color tone of the wood grain may be reversed. Absent.

Next, specific examples and comparative examples of the present invention will be shown. Example 1 A thickness of 0.5 mm, a width of 10 cm, a length of 1 m, and a water content of 15% to a venetian hemlock veneer, and a phenol resin aqueous solution having a resin nonvolatile content of 15% by weight under a reduced pressure of 40 Torr for 30 minutes at 5 kg / cm ^2. Under pressure of 30
Min, pressure reduction and pressure injection were performed. Then, this resin-injected veneer is heated in a hot air dryer at 60 ° C. for half a day,
After drying, it was heated for 45 minutes by a hot platen press at 145 ° C. to obtain a phenol resin-injected cured veneer having a weight gain of 23%. Next, a resin solution prepared by adding a small amount of a polymerization initiator (benzoyl peroxide) to a mixed liquid of an unsaturated polyester: methyl methacrylate = 50: 50 addition polymerization type resin is depressurized / pressurized to the above-mentioned phenol resin injection cured veneer. Pressurized. After injection, hot plate press at 130 ℃, 10Kg / c
When heat-pressed at m ² for 30 minutes, a modified veneer was obtained in which the wet color was imparted to the whole, but the color tone of the natural wood was left as it was.

Example 2 A melamine resin aqueous solution having a resin nonvolatile content of 15% by weight was placed on a cypress veneer having a thickness of 0.5 mm, a width of 10 cm, a length of 1 m and a water content of 15%.
Decompression / pressurization injection was carried out for 30 minutes under a reduced pressure of 40 Torr and for 30 minutes under a pressure of 5 kg / cm ² . Next, this resin-injected veneer was heated and dried by the same treatment method as in Example 1 above to obtain a melamine resin-injected cured veneer having a weight increase rate of 20%. Next, when the mixed solution of the addition polymerization type resin shown in the above-mentioned Example 1 was injected into this single plate under reduced pressure / pressurization and subjected to hot pressure treatment under the same conditions as in Example 1, the wet color slightly increased. A modified veneer having a plain wood appearance was obtained.

Comparative Example 1 The mixture of addition polymerization type resins shown in Example 1 was directly injected and cured under the same conditions without injecting the phenol resin solution into the venetian hemlock veneer in Example 1. In the obtained resin-injection-cured veneer, the spring material was transparent, and there was a large amount of resin filling between the summer material and the spring material adjacent to this summer material. Had an inverted appearance pattern.

Comparative Example 2 Without adding the melamine resin solution to the cypress veneer in Example 2, the addition polymerization type resin mixture shown in Example 1 was directly injected and cured under the same conditions. The obtained resin-injection-cured veneer was dark-colored and transparent throughout, and had an oil-paper-like appearance with no obvious grain.

[0027]

As described above, according to the method for producing a synthetic resin-injected wood material of the present invention, a wood material with little lightness of the spring material and the summer material, or a difference in porosity between the spring material and the summer material can be obtained. After thermosetting resin such as phenol resin is impregnated and cured into a large wood material so that large voids such as cell lumen of the wood material remain, the addition polymerization type resin liquid having transparency is added to the voids. Since it is characterized in that it is filled and cured by hot pressing, thermosetting resin is preliminarily impregnated and cured into the cell wall, which is the substantial part of the wood, so that the compressive strength of the wood can be increased. At the same time, it is possible to reduce the impregnation of the addition polymerization type resin liquid to be injected next to reduce the injection amount of the addition polymerization type resin liquid, and it is possible to eliminate transparency due to excessive injection of the resin liquid, Transparency darkening even in lightly shaded wood such as cypress Can be avoided, it presented an appearance color tone of the natural wood grain Sonoma ゝ left behind, pressure resistance, it is possible to obtain scratch resistance, modified wood material having improved durability.

In addition, when the addition polymerization type resin liquid is injected and then heat-treated, the cell wall of the wood material is impregnated and hardened by the thermosetting resin, so that the softening phenomenon of the cell wall is prevented and the spring material voids and the like. In addition to reducing the possibility of compressive deformation at the time of injection, the injection amount of the addition polymerization type resin liquid described above is reduced, and the selectivity of injection of the addition polymerization type resin liquid by the thermosetting resin impregnated and cured into the cell wall is decreased. Thus, it is possible to obtain a modified wood material in which the excessive injection of the resin liquid is partially eliminated to cause partial transparency and darkening, and the color tone of the grain is not reversed.

Therefore, according to the present invention, a resin-injection-treated wood material having an appearance in which the natural wood grain of the wood material is left as it is, is stable without using a special whitening resin as in the prior art. In addition, it can be produced efficiently. or,
There is also an advantage that it is possible to obtain resin-injection-treated wood material with inverted wood grain called resin-like pine pattern and resin-injection-treated wood material without reversal in the same production line by using the same transparent resin liquid. It is a thing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Miura 2-3-3 Nakanoshima, Kita-ku, Osaka City Daiken Industry Co., Ltd.

Claims (1)

[Claims] 1. A thermosetting resin liquid such as a phenol resin is applied to a wood material having a small difference in density between spring wood and summer wood or a wood material having a large difference in porosity between spring wood and summer wood. After impregnating and curing so that voids such as cell lumens remain, the addition polymerization resin liquid having transparency is filled in the voids, and the mixture is heated and pressed to cure the synthetic resin-injected wood material. Production method.