JP2954748B2 - Method for producing synthetic resin-injected wood - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a synthetic resin-injected wood material having improved physical properties such as desired hardness, scratch resistance and durability without substantially changing the grain pattern of the wood material.

[0002]

2. Description of the Related Art Conventionally, wood materials are injected with a synthetic resin solution,
So-called hardness, scratch resistance, durability, etc. modified by curing
A resin-injected wood material called WPC is known.
In order to manufacture such a resin-injected wood material, an addition polymerization type resin liquid such as acrylic, styrene, or polyester resin is injected and filled into voids in the wood material, and then subjected to radical polymerization with heat or radiation. A curing method is employed.

[0003]

However, if such a resin injection treatment method is applied to a tree species such as cypress, spruce, spruce, etc., which has a small difference in color between spring and summer materials, the whole is transparent and dark. It is colored to give an oil-paper-like appearance, and when it is adopted for a tree species such as pine and hemlock with a large gap in the spring wood portion, the resin filling rate of the spring wood portion is increased, resulting in a transparent dark color. However, there has been a problem that the color tone of the wood is reversed and the color tone of the wood fabric disappears.

[0004] The reason why the entire wood material is made dark and transparent is that when the resin is filled in the voids of the wood material, the refractive index of light changes, and the resin liquid injected into the wood material is heated and pressed. The wood material is easily compressed and deformed compared to dry wood due to the wetting by the resin liquid and the heating at the time of heat and pressure, and the resin injected in the compressed and deformed state is hardened. Is thought to be raised. In addition, the color tone of the wood grain is inverted because the resin liquid is selectively injected into the spring wood part with a large wood void,
It is presumed that, similarly to the above, a large compressive deformation occurs in a portion having a large gap at the time of hot pressing, and the resin is fixed in an excessively filled state. If the degree of heat pressure is reduced or the resin is cured by heating in an oven, unevenness in the curing of the injected resin and uneven distribution of the resin occur, causing problems in product stability and productivity.

[0005] Therefore, as described in JP-B-62-1820, a wood material is impregnated with a thermosetting resin to which a non-copolymerizable low-boiling solvent is added, and the solvent is volatilized during hot pressing. There is a method in which light is dispersed by causing bubbles in the resin to generate light.However, in such a resin injection processing of a wooden material, the entire material is whitened and the color tone of the wooden material is lost. , Air bubbles are unevenly distributed depending on the curing method, poor curing may occur due to the components of the wood material,
There is a problem that adjustment at the time of manufacturing is difficult.

The present invention has been made in view of such a problem, and the conventional resin injection treatment method has been applied to a tree type in which the entire wood is transparent or the color tone of the wood grain pattern is reversed. An object of the present invention is to provide a method for producing a synthetic resin-injected wood material for the purpose of injecting a resin so as to exhibit a color tone.

[0007]

In order to achieve the above-mentioned object, a method for producing a synthetic-wood-injected wood material according to the present invention comprises the steps of: A wood-based material with a large difference in porosity is impregnated and cured with a thermosetting resin liquid such as a phenolic resin so that large voids such as cell cavities in the wood-like material remain. A resin liquid is filled in the gap, and the resin is cured by applying heat and pressure.

[0008]

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

[0009]

The present invention will now be described in more detail with reference to the following examples. The heat is adjusted to a concentration 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. When the curable resin liquid has a water content below the fiber saturation point (50
% Water content). In addition, as the thermosetting resin mentioned here, in addition to polycondensation type resins such as phenol, melamine, and urea, resins such as epoxy resin, acrylic resin, and urethane resin that do not easily soften at the time of hot-pressing described below are used. To tell.

The resin solution is injected into the wooden material by a reduced pressure or pressure injection method. However, the resin solution may be injected by a dipping or diffusion method so that the resin aqueous solution is uniformly injected and impregnated into the wooden material. A method and conditions suitable for the shape and size of the timber, permeability, and 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 penetrate 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 the species of the wood is coniferous, such as cypress, pine, hemlock, spruce, etc. It is applied to materials with a small difference in shading, and southern materials having a large gap in the spring material and good permeability of resin liquid.

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

After injecting the thermosetting resin liquid into the wooden material in this way, the resin-injected wooden material is heated and dried by high frequency under reduced pressure while paying attention to the occurrence of warpage, cracks, etc., and the thermosetting resin impregnated in the wooden material is impregnated. Evaporates and eliminates solvents and the like in the hydrophilic resin liquid. In addition, you may perform using a hot-air dryer as a 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 inside a large space such as a cell cavity of a wooden material to the outside, and the resin is not filled. While the void (cell lumen) is formed, the resin remains sealed in the cell wall or filled in small voids in the wall. Such heating and drying treatments are performed at a temperature of 80 to 160 ° C. for several minutes to several hours depending on the type of the resin.

When the rate of weight increase 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 cavities in the wood material, the cell surface is sealed or the resin is sufficiently injected into the cell wall and hardened.

In this case, if the resin filling rate in the void portion of the wood material becomes high, adverse effects such as coloring and cost increase due to the resin occur.
The concentration is adjusted within the range of 50% by weight or less.

In this way, when the thermosetting resin liquid is injected and hardened on the cell wall of the wooden material, the impregnation of the next addition-polymerized resin liquid to be injected is reduced, and the compressive strength of the wooden material is improved. The compressive strength varies depending on the type of wood, the cutting of wood, and the coarse density of the grain. However, when the grain face or straight grain face is pressed, the compression proportional limit is 5 to 50 kg / cm ² =, which will be described later. What is necessary is just to select heat-pressure processing conditions according to the compression proportional limit.

After injecting and curing the above resin solution into the cell wall of the wood material, the addition polymerization type resin solution is then filled into the hollow space by removing the solvent in the wood material and hardened. At this time, since the thermosetting resin is injected and hardened into the cell walls 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 the filling and curing step, the above-mentioned heat-curable resin is injected and cured into a transparent resin liquid mainly containing a hydrophobic addition-polymerizable monomer alone or a hydrophobic addition-polymerizable prepolymer as a main component. Or by applying and injecting the resin solution onto the treated wood material, and this operation can be performed under reduced pressure or under increased pressure.

The hydrophobic addition-polymerizable monomer used in this step includes styrene monomer, methyl methacrylate, styrene oxide, epichlorohydrin, divinylbenzene and the like.

Examples of the addition polymerizable prepolymer include vinyl polymer acrylate, melamine polymerizable acrylic prepolymer, unsaturated polyester prepolymer, acrylic urethane prepolymer, epoxy prepolymer and the like. In addition, a reaction initiator, a plasticizer, a colorant, and / or a flame retardant can be appropriately 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 following step. In this hardening step, if necessary, the wooden material is pressed and heated by a hot plate press at 80 to 250 ° C. and 5 to 50 kg / cm ² =. At the time of this heat and pressure, the thermosetting resin is filled in the cell wall of the wood material in advance, and the cell wall is hardened. In addition, as described above, since the injection amount of the addition polymerization type resin solution is limited, the wood material is not excessively darkened with transparency, and the color tone of the grain may be inverted. Absent.

Next, specific examples and comparative examples of the present invention will be described. Example 1 A phenol resin aqueous solution having a resin nonvolatile content of 15% by weight was applied to a veneer veneer veneer having a thickness of 0.5 mm, a width of 10 cm, a length of 1 m and a water content of 15% under a reduced pressure of 40 Torr for 30 minutes at 5 kg / cm ^2. 30 under pressure
The pressure and pressure were injected for minutes. Next, this resin-injected veneer was heated in a hot air dryer at 60 ° C. for half a day,
After drying, the plate was heated by a hot plate press at 145 ° C. for 45 minutes to obtain a phenol resin injection cured veneer having a weight increase rate of 23%. Next, a resin solution obtained by adding a small amount of a polymerization initiator (benzoyl peroxide) to a mixed solution of an unsaturated polyester: methyl methacrylate = 50: 50 addition polymerization type resin is applied under reduced pressure and pressure to the phenol resin injection-cured veneer. Pressure injection. After injection, hot plate press at 130 ℃, 10Kg / c
When subjected to a heat and pressure treatment 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 grain was left as it was.

Example 2 A melamine resin aqueous solution having a resin nonvolatile content of 15% by weight was applied to 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%.
The reduced pressure / pressure injection was performed under a reduced pressure of 40 Torr for 30 minutes and at a pressure of 5 kg / cm ² for 30 minutes. Next, the resin-injected veneer was heated and dried by the same processing method as in Example 1 to obtain a melamine resin-injected veneer having a weight gain of 20%. Next, the mixed solution of the addition polymerization type resin shown in the above Example 1 was injected into this veneer under reduced pressure and pressure, and subjected to hot pressure treatment under the same conditions as in Example 1. As a result, the wet color slightly increased. Thus, a modified veneer having a white wood appearance was obtained.

COMPARATIVE EXAMPLE 1 A mixture of the addition polymerization type resin shown in Example 1 was directly injection-cured under the same conditions without injecting the phenolic resin solution into the veneer veneer veneer in Example 1. In the obtained resin-injection-hardened veneer, the spring material is transparent and there is a large amount of resin filling between the summer material and the spring material adjacent to the summer material, as if the wood grain color Exhibited an inverted appearance pattern.

Comparative Example 2 A mixture of the addition polymerization type resin shown in Example 1 was directly injection-cured under the same conditions without injecting the melamine resin liquid into the cypress veneer in Example 2. The obtained resin injection-cured veneer had a deep, transparent color, and exhibited an oil-paper-like appearance with no apparent grain.

[0027]

As described above, according to the method of manufacturing a synthetic resin-injected wood material of the present invention, a wood material having a low density of spring wood and summer wood or a difference in porosity between spring wood and summer wood is used. On a large wooden material, a thermosetting resin such as a phenolic resin is impregnated and cured so that a large void portion such as a cell cavity of the wooden material remains, and then a transparent addition polymerization type resin liquid is applied to the void portion. Since it is characterized by being filled and cured by heat and pressure, a thermosetting resin is impregnated and cured in advance on the cell wall, which is a substantial part of the wooden material, so that the compressive strength of the wooden material can be increased. In addition, it is possible to reduce the impregnation of the addition polymerization type resin liquid to be injected next, thereby reducing the injection amount of the addition polymerization type resin liquid, and eliminate the transparency caused by excessive injection of the resin liquid, Transparent darkening of wood with low shade 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, during the heat and pressure treatment after the injection of the addition polymerization type resin liquid, the thermosetting resin impregnated and hardened on the cell wall of the wood material prevents the softening phenomenon of the cell wall, and the spring material voids etc. In addition to reducing the amount of injection of the addition-polymerization resin liquid described above, the selectivity of injection of the addition-polymerization resin liquid by the thermosetting resin that has been impregnated and cured on the cell walls is reduced. In addition, it is possible to obtain a modified wood material in which the partial injection of the resin liquid is partially eliminated, partial transparency and darkening do not occur, and the color tone of the grain is not inverted.

Therefore, according to the present invention, a resin-injected wood material having an appearance that retains the natural woodgrain of the wood material without using a special resin for whitening as in the prior art can be obtained stably. It can be produced efficiently and efficiently. or,
There is also an advantage that a resin injection-treated wood material having a reversed grain pattern called a pine pine pattern and a resin injection-treated wood material that is not inverted can be obtained on the same production line by using the same transparent resin liquid. Things.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B27K 3/00-3/15

Claims (1)

(57) [Claims] 1. A thermosetting resin liquid such as a phenolic resin is added to a wood material having a small shade of spring wood and summer wood, or a wood material having a large difference in porosity between spring wood and summer wood. After impregnated and cured so that voids such as cell cavities remain, filling the voids with an addition-polymerizable resin liquid having transparency, and heat-pressing and hardening the synthetic resin-injected wood material. Production method.