JPH08216113A - Resin-reinforced broad-leafed tree veneer holding feel of raw material, and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a resin-reinforced broad-leafed tree veneer which has a feel of raw material and in which the hardness is improved. CONSTITUTION: A resin-reinforced broad-leafed tree veneer comprises resin having a molecular weight of 2,000 to 4,500 and resinous solution made of polymerizable monomer to be cured by heat and filled in the wood fiber bore and vessel of the veneer and then the solution is cured. The packing ratio of the cured resin after curing is 20vol.% or less in the bore, 60 to 90vol.% in the vessel, and the hardness of the reinforced veneer by a Barcol method is 40 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-reinforced wood veneer (WPC), and in particular, a natural hardwood veneer (hereinafter, also referred to simply as veneer), a housing building material,
The present invention relates to a resin-reinforced hardwood veneer that retains a texture and can be used as a veneer for makeup such as housing equipment and furniture, and a method for producing the same.

[0002]

2. Description of the Related Art A technique for improving hardness, durability, dimensional stability and the like by injecting or impregnating a natural hardwood veneer with a resin is known as a so-called WPC technique.
However, although the technique of WPC treatment is excellent in that it improves hardness, durability, and dimensional stability, the veneer is semitransparent and exhibits a so-called "wet color", which is a beautiful material peculiar to natural hardwood. There was a drawback that the feeling was lost.

Therefore, the present inventor has conducted earnest research on a technique of imparting hardness and durability, which are the original purpose of resin treatment, without losing the texture of hardwood.
In the WPC treatment of hardwood veneers, the reason why the veneers become translucent and "wet color" is due to the filling rate of the resin inside the canal, which is the main constituent tissue of the hardwood, and the cell lumen of the wood fiber. It turned out to be too expensive. That is, when the filling rate of the resin is increased, the optical refractive index of the resin is close to the optical refractive index of the cell wall, so that the whole becomes semi-transparent and the original texture of the veneer is reduced, and a "wet color" is exhibited. .

[0004]

Therefore, in order to prevent the occurrence of "wet color", it is necessary to diffusely reflect the transmitted light inside the single plate. However, it is generally assumed that the hardness becomes low when the resin filling rate is low. Therefore, if the wood fiber lumen is filled with only a small amount of resin, satisfactory hardness cannot be obtained as a resin-reinforced single plate. There was a fear. However, in reality, even if the resin is hardly filled in the wood fiber lumen, the resin filling rate in the vessel is 60%.
If it is at least volume%, the hardness will be sufficiently high.

That is, as a result of intensive investigations by the present inventors in order to obtain a WPC which does not exhibit a wet color and has sufficient hardness, the resin filling rate of the wood fiber lumen depends on the hardness of the resin-reinforced veneer. It was found that the degree of resin filling in the conduit is a larger factor than the hardness, rather than the large factor that affects the hardness. Therefore, an object of the present invention is to provide a resin-reinforced hardwood veneer that retains a natural beautiful texture.

[0006]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
The molecular weight of the hardwood veneer wood fiber is 20
A resin-reinforced hardwood veneer obtained by injecting a resin liquid comprising 00 to 4,500 resin and a heavy monomer that is hardened by heat together with the resin, and then hardening the resin liquid. The resin filling rate is 20% by volume or less in the wood fiber lumen, 60 to 90% by volume in the vessel, and the hardness of the reinforced veneer by the Barcol method is 40 or more. Achieved by a resin-reinforced hardwood veneer that retains the feeling.

In the present invention, in order to diffusely reflect transmitted light inside the veneer, it is necessary to limit the amount of resin injected into the veneer to form voids. Hardness cannot be improved as a reinforced veneer. Therefore, in the present invention, a small amount of resin is filled in the wood fiber lumen, and the filling rate in the vessel is 60% to 90%.
%, Preferably 60% to 85%. by this,
While it does not exhibit a "wet color" in general and can retain the texture, it has a hardness of 40 or more according to the Barcol method and can be sufficiently adapted to the use as a resin-reinforced single plate.

The resin used in the resin-reinforced hardwood veneer of the present invention includes known curable resins such as epoxy resin and unsaturated polyester resin, as well as polyester resin and polyamide resin having no reactive functional group. Has a molecular weight of 2,000
It can be appropriately selected from known resins of 0 to 4,500, but in the present invention, it is preferable to use a resin having a reactive functional group, and particularly it is possible to react with a polymerizable monomer described later. Preference is given to using unsaturated polyester resins.

When the molecular weight of these resins is less than 2,000, the resin is relatively easily injected into the lumen of a very small wood fiber, but when the molecular weight exceeds 2,000, a relatively large wood fiber is obtained. Only injected into the lumen. When the molecular weight exceeds 4,500, it is hardly injected into the wood fiber lumen under the pressure normally used. On the other hand, if the molecular weight is 4,500 or less, the resin can be relatively easily injected into the conduit regardless of the molecular weight.

Therefore, when a resin having a molecular weight of 2,000 to 4,500 is used, it is possible to prevent the resin from penetrating into the inner cavity of the wood fiber and achieve the purpose of filling the resin into the vessel. In particular, the molecular weight is 3,000 to 4,0.
It is preferably between 00. The resin having the above molecular weight range is diluted with a polymerizable monomer and the concentration thereof is 60 to
By using a 65% resin solution, it can be injected into the wood fiber lumen and the canal. Examples of the polymerizable monomer include those having a polymerizable unsaturated bond such as styrene and (meth) acrylic acid.

In injecting the resin liquid (reaction liquid), first, a single plate to be injected with a resin liquid containing a reaction initiator appropriately selected from known polymerization initiators such as organic peroxides. Is put in a pressure cooker, degassed under reduced pressure, and then injected under reduced pressure or normal pressure. Alternatively, there is a method of returning to normal pressure and then injecting the resin liquid in a pressurized state. In the former method, the difference between the resin filling rate in the wood fiber lumen and the resin filling rate in the vessel is generally larger.

Similarly, when the pressure is increased, the difference between the resin filling rate in the wood fiber lumen and the resin filling rate in the conduit increases as the pressure is lowered. The time required for the injection depends on whether the resin liquid is injected under reduced pressure or under pressure. Further, how to set the pressure in the case of pressurization is determined in relation to the time required for injection.

The correlation between the injection pressure and the time required for the injection may be appropriately selected from the viewpoint of work efficiency and economy, but pressurization of 30 kg / cm ² or less is particularly practical.
The amount of resin liquid to be injected must be 99% or more, that is, almost 100% in the vessel. If it is 99% or less, large bubbles or the like are partially generated due to uneven injection after the resin liquid is cured, and the appearance of the veneer is impaired.

By selecting the composition of the resin liquid to be injected or the type thereof and the curing conditions, it is possible to make the cured resin in the wood fiber lumen 20% or less and the cured resin in the vessel 60 to 90% by volume. The hardness of a single plate by the Barcol method can be set to 40 or more. The curing conditions of the injected resin liquid have a great influence on the formation of voids in the vessel.

The resin is not only polymerized and shrunk when it is cured, but also a part of the monomer is dissipated outside the veneer, so that 10-40% of voids are formed in the vessel after curing. For example, when polyester resin is used as the resin,
It is preferable to cure at a high temperature of 160 ° C. for a short time.
When cured at a low temperature of 130 ° C. or less, the degree of polymerization does not increase because the curing proceeds slowly, the polymerization shrinkage rate is low, and the amount of monomer dissipated is small, so voids are less likely to occur in the vessel. As a result, "wet color" is exhibited, and the texture is impaired.

Also, since the veneer itself shrinks by heating, the curing temperature of the resin depends on the resin liquid used.
The temperature must be adjusted so that the shrinkage rate of the injected resin liquid is higher than the shrinkage rate of the veneer. The shrinkage ratio of the resin becomes larger than that of the veneer as the curing temperature increases, so it is desirable to cure at as high a temperature as possible, but if the temperature is 160 ° C or higher, the resin is likely to deteriorate or partially generate large bubbles. , It causes the appearance of veneer to be impaired. A preferable temperature range is 135 ° C to 155 ° C, and a range of 140 ° C to 150 ° C is particularly preferable.

Even in the case of other resin liquids, when the curing temperature is raised, the resin shrinks rapidly, so that the optimum conditions of heating temperature and heating time differ depending on the resin used. In the present invention, in particular, the sum of the vessel filling rate and the wood fiber lumen filling rate is 6
The range of 5 to 90 is preferable. In the present invention, a colorant is mixed in the injected resin liquid to give a light color (so-called natural color) or a dark color (so-called brown color).
It can also be finished into a system.

Further, since most of the resin liquid is filled in the pipe, by mixing a coloring agent into the resin liquid, the pipe portion is particularly emphasized to produce a so-called "wood grain" decorative veneer. be able to. Since most of the colorants have a molecular weight of 1,000 or less, they can be easily injected into the vessel together with the resin liquid. Therefore, most colorants can be used, except for large particle pigment systems.

[0019]

EFFECT OF THE INVENTION The resin-reinforced hardwood veneer of the present invention has 80% by volume or more of voids in the wood fiber lumen and 10-40% by volume of voids in the vessel, so that transmitted light is diffusely reflected in the veneer, As a result, despite being resin-reinforced, it retains the texture of natural hardwood and has the strength peculiar to resin-reinforced wood.

[0020]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. Example. The oak veneer having a thickness of 0.6 mm is dried by an air-blowing dryer, the water content is adjusted to 11.5%, and the water is put into a vacuum vessel to be degassed under a reduced pressure of 10 Torr, and then shown in Table 1 or Table 2. Thus, a resin solution containing 65% of a resin having a molecular weight of 1,000 to 4,000 was injected under reduced pressure or increased pressure.

After returning to normal pressure to remove excess resin, it was heated and cured using a blower dryer. As the resin, 100 parts of an unsaturated polyester resin (manufactured by Dainippon Ink and Chemicals, Inc., trade name: USPR) was added with a reaction initiator (manufactured by NOF Corporation, trade name: Nyver FF).
Using 5 parts added, a resin solution was prepared by diluting with a styrene monomer so that the resin concentration became 65%.

The measurement of the filling rate of the resin into the inner cavity of the wood fiber in the obtained resin reinforced veneer is carried out by first measuring a sample of the reinforced wood veneer filled and hardened with the resin by 2 cm in the direction orthogonal to the fiber.
The measurement was performed by cutting the sample into ten pieces, observing the cut cross section with a magnifying glass, and determining the area of the wood fiber lumen and the area of the wood fiber lumen filled with resin, respectively.

The calculation of the resin filling rate is a ratio of the total area filled with the resin and the total area of the wood fiber lumen of the above 10 samples. The resin filling rate in the conduit was determined in the same manner, and the hardness of the resin-reinforced wood veneer was measured by the Barcol method. In addition, in judging the quality of the material, a veneer veneer of the same quality and the same thickness, in which no resin was injected at all and a resin in which almost 100% of the resin was injected into the wood fiber lumen and the canal, were attached to the plywood. After that, a transparent paint finish was applied to make the "material standard sample" and "wet color standard sample".

As in the case of the above sample, each sample was attached to a plywood board, subjected to a transparent coating finish, and compared with a standard sample. Judgment was made by visual inspection, and 100% was judged to be closer to the "material standard sample" than the "wet color standard sample", and it was judged to be closer to the "material standard sample" than the "wet color standard sample". The ratio of 60 to 90% is indicated by Δ, and the others are indicated by X.

The preparation conditions of the sample and the evaluation results of the obtained sample are as shown in Tables 1 and 2.

[Table 1]

[0026]

[Table 2]

From the results of Tables 1 and 2, the resin-reinforced hardwood veneer, which is the object of the present invention and which has the hardness necessary for the resin-reinforced wood veneer while maintaining the texture, is the resin filling ratio of the wood fiber lumen. Is 20% by volume or less, and the resin filling rate in the conduit is 6
It was proved that the hardness was 0 to 90% by volume and the hardness by the Barcol method was 40 or more. It was also proved that the material having a sum of the filling rate in the vessel and the filling rate in the wood fiber lumen is in the range of 65 to 90 is particularly excellent in texture.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Inui 2-8-1 Iida-cho, Iwakuni-shi, Yamaguchi Nihon Paper Co., Ltd.

Claims (5)

[Claims] 1. A hardwood veneer wood fiber lumen and vessel
A resin-reinforced hardwood veneer obtained by injecting a resin liquid comprising a resin having a molecular weight of 2,000 to 4,500 and a heavy monomer that is hardened by heat together with the resin, and then hardening the resin liquid, The filling rate of the cured resin after curing is 20% by volume or less in the wood fiber lumen and 60 in the vessel.
A resin-reinforced hardwood veneer that retains the feeling of material, characterized in that it is ˜90% by volume and the hardness of the reinforced veneer by the Barcol method is 40 or more. 2. The resin-reinforced hardwood veneer having the texture as set forth in claim 1, wherein the resin having a molecular weight of 2,000 to 4,500 is an unsaturated polyester resin. 3. A step of degassing the air in a veneer of a hardwood veneer under reduced pressure, a resin liquid comprising a resin having a molecular weight of 2,000 to 4,500 and a polymerizable monomer which can be cured together with the resin, in a duct. A method for producing a resin-reinforced hardwood veneer that retains a feeling of texture, which comprises performing a step of injecting or impregnating 99% or more of the above with a step of heating with blowing air at 130 ° C to 160 ° C. 4. The method for producing a resin-reinforced hardwood veneer having a material feeling according to claim 3, wherein the resin having a molecular weight of 2,000 to 4,500 is unsaturated polyester. 5. The method for producing a resin-reinforced hardwood veneer according to claim 4, wherein the content of the unsaturated polyester resin in the resin liquid is 60 to 65% by weight.