JP2012250439A - Method for manufacturing woody board reduced in noxious chemical substance, and woody board reduced in noxious chemical substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a woody board reduced in noxious chemical substance which is the cause of sick house syndrome, to a significant level while securing adhesion durability and operability using petroleum resin such as phenol resin, melamine resin, urea resin or isocyanate resin for an adhesive in the woody board.SOLUTION: The method for manufacturing the woody board reduced in noxious chemical substance includes forcibly diffusing a noxious chemical substance produced by heating the adhesive, to the outside by an ejection means while applying or spraying the adhesive to a wood feedstock comprising an assembly of at least one of a veneer-like material, a sheet-like material loosened by rolling, a thin stick-like material, a flake-like material and a stranded material, to form the woody board by thermocompression of a hot press provided with a pair of heating plates.

Description

  The present invention relates to a technology for reducing harmful chemical substances related to a wood board formed by heat-pressing a wood raw material composed of an aggregate of a single plate, a fiber, a particle, a flake, a strand and the like together with an adhesive. More specifically, the present invention relates to a harmful chemical substance reduction technique in which harmful chemical substances generated due to an adhesive during hot pressing are forcibly discharged together with the hot pressure.

In the construction field such as houses, harmful chemical substances released from various building materials such as volatile organic compounds (VOC) such as formaldehyde, acetaldehyde, toluene, ethylbenzene, xylene and styrene, and odorous components such as ammonia Occurrence of so-called sick house syndrome is a problem.

The current situation is that the same problem cannot be avoided even in wood boards widely used as wall materials. The wood board is generally obtained, for example, by laminating a mixture of a chip and an adhesive, pressurizing and heating the particle board, insulation board, MDF (Medium).
Wooden boards such as Density Fiberboard) and hardboards are known and used mainly for building materials.

  These boards can be made from waste wood, factory scraps, etc., and can effectively use wood resources. Adhesives are generally made of phenol resin, melamine resin, urea resin, isocyanate resin, etc. Since these are petroleum resins and many of these adhesives release various harmful chemical substances including formaldehyde into the air, the occurrence of sick house syndrome is inevitable.

In order to solve such a problem, for example, a technique for bonding a wood molding material using a natural material such as cellulose, starch, or lignin as an adhesive is known.
However, conventional wood-based materials using such natural materials as adhesives are inferior in adhesive strength, water resistance, and insect repellent properties, and cannot be used for applications that require strength, and are expensive. There was a problem of becoming.
The following prior art documents exist in relation to the present invention.
Japanese National Patent Publication No. 11-503476 JP-A-9-249862 JP 2001-347510 A

While the invention of the present application ensures the durability and operability of adhesives by using petroleum resins such as phenol resins, melamine resins, urea resins, isocyanate resins as adhesives in the wood board manufacturing technology, harmful chemical substances The purpose is to provide a wooden board that can reduce the occurrence of sick house syndrome to a meaningful level.

  The gist of the present invention is to solve the above-mentioned conventional problem by forcibly discharging both harmful water vapor generated by the heat pressure of the adhesive together with the water vapor generated inside the wood raw material during the hot pressure formation of the wood board. The details are as follows.

    In the present invention, an adhesive is applied or distributed to a wood raw material composed of a single plate-like material, a fiber-like material, a particle-like material, a flake-like material, a strand-like material, and an aggregate containing at least one of the strand-like materials. To reduce harmful chemical substances by forcibly dissipating harmful chemical substances generated by heating the adhesive to the outside by means of discharging, in addition to forming a wooden board by the hot pressure of a hot press equipped with a pair of hot plates It is an object of the present invention to provide a method for manufacturing a wooden board to solve the above-mentioned conventional problems.

Further, in the method for manufacturing a hazardous chemical substance-reduced wood board described in the paragraph 0008, the discharge means may be constituted by a high-pressure air flow blown out from one hot platen.

Further, in the method for manufacturing a wooden board with reduced harmful chemical substances according to paragraph 0009 above, the high-pressure air flow is introduced through one hot plate and the harmful chemical substances are sucked and discharged together with water vapor from the other hot plate. There is.

  In the method for manufacturing a wooden board with reduced harmful chemical substances according to any one of paragraphs 0008 to 0010, the hot press may be constituted by a continuous hot press.

In the method for manufacturing a wooden board with reduced harmful chemical substances according to paragraphs 0008 to 0011, a high-frequency wave may be used for the wooden raw material to which an adhesive is applied or distributed during hot pressing.

  The invention of the present application is also obtained by solidifying and molding a wood raw material comprising at least one kind of a single plate, fiber, particle, flake, strand, and strand with an adhesive. In the wood board, the above-mentioned conventional problem is solved by realizing a harmful chemical substance-reduced wood board in which harmful chemical substances related to the adhesive are diffused to the outside by heating the adhesive.

In the wood board with reduced harmful chemical substances described in paragraph 0013, the adhesive may be heated by hot pressing the wood board, and the harmful chemical substances generated by heating may be forcibly discharged outside the wood board. is there.

Further, in the wood board for reducing harmful chemical substances described in paragraph 0014, the hot pressing of the wood board is configured by a hot press having a discharge means forcibly dissipating the harmful chemical substances generated by heating the adhesive to the outside. Sometimes.

The invention of the present application ensures the adhesive durability and operability as usual by using petroleum-based resins such as phenol resin, melamine resin, urea resin, isocyanate resin as an adhesive, as described above. It is possible to provide a wooden board with reduced substances and a significant reduction in the occurrence of sick house syndrome.

The wood raw material used in the present invention can be of any shape such as a single plate, fiber, particle, flake and strand, all from the inside of the wood raw material during hot pressing. The water vapor can be effectively released, and a harmful chemical substance is attached to the water vapor and diffused to the outside along with the water vapor.
Wood board manufactured is plywood, OSB (Oriented
Strand board), fiber board, particle board, etc., but in any case, toxic chemicals adhere to the water vapor generated inside the wood raw material during hot pressure and are forcibly discharged outside, so-called puncture prevention And effective reduction of harmful chemical substances caused by adhesives.

Adhesives added to the wood material can prevent puncture and reduce harmful chemical substances in all conventionally used adhesives such as urea resin, melamine resin, phenol resin and isocyanate resin.

Although the temperature of a general hot press varies depending on the type of each adhesive and wood material, it is 120 ° C. to 220 ° C. and is not particularly affected by the action of the hot press temperature in the present invention.

  Hazardous chemical substance reduction wood board manufacturing device in the present invention comprises a hot pressing part, heat presses the wood raw material to which the adhesive is added, and bonds the wood raw material by curing the adhesive to combine plywood, particle board, fiber board and other A structure for forming a woody material is provided, and a discharge means for forcibly dissipating harmful chemical substances along with water vapor generated and staying inside the wood raw material at the time of hot pressure is provided in the hot pressure part. The harmful chemical substances include formaldehyde generated from organic solvents and preservatives contained in the adhesive, VOC (Volatile Organic Compounds), that is, toluene, benzene, chlorofluorocarbons, dichloromethane, and the like. VOC is a general term for organic chemical substances that readily volatilize in the atmosphere at normal temperature and pressure, and causes environmental pollution due to the generation of sick house syndrome, sick building syndrome, photochemical oxidants, and the like.

The discharge means comprises a high-pressure air supply means connected to the wood raw material and a high-pressure air source connected to the wood raw material. When the wood raw material is hot-pressed, the high-pressure air is supplied from the high-pressure air supply means to supply the wood raw material. A structure is provided that pressurizes both the upper and lower surfaces and forcibly dissipates water vapor and harmful chemical substances that are generated and accumulated in the wood raw material as the supplied high-pressure air is exhausted from the side of the wood raw material.
The discharge means having such a configuration may be configured by providing a high pressure air discharge hole in the hot pressure section, that is, the hot platen. However, the high pressure air is sent through a casing that is bonded to the hot plate surface and abuts against the wood material. It is also possible to use a configuration that supplies the power.

  The higher the pressure of the high-pressure air in the discharge means, the more effective. However, the pressure of the compressed air obtained by a general compressor can provide a sufficient effect for discharging internal water vapor or the like to which harmful chemical substances are attached.

  If the above-mentioned discharge means is provided with a structure that performs an intake action in addition to the above-mentioned pressurizing action on the wood raw material at the time of hot pressure, the internal water vapor discharge effect is further improved. That is, the discharge means includes an exhaust means connected to the wood raw material and an intake source connected to the exhaust means, and the wood raw material is sucked by the exhaust means and the intake source connected thereto when the wood raw material is hot-pressed. In addition to reducing the pressure, the steam is generated and diffused together with the harmful chemical substances together with the water vapor generated and retained in the wood raw material in accordance with the exhaust flow from the exhaust means.

  Each structure of the discharge means described above is also effective in a so-called continuous hot press apparatus. That is, it has a hot-pressing part that continuously heat-presses the wood raw material to which the adhesive is added, and bonds the wood raw material by curing the adhesive to continuously form plywood, particle board, fiber board and other woody materials. In the continuous hot press apparatus, a discharge means for dissipating water vapor generated and accumulated in the wood raw material during hot press is provided in the hot pressure section, and this discharge means communicates with the high pressure air supply means joined to the wood raw material. A high-pressure air source that supplies the high-pressure air from the high-pressure air supply means when the wood raw material is hot-pressed to pressurize the wood raw material in both upper and lower sides, and the supplied high-pressure air is used as the wood raw material. In addition to exhausting from the side of the wood, it is also harmful without the fear of so-called puncture by dissipating it together with harmful chemical substances generated and staying inside the wood raw material The reduced high-quality wood boards were academic material can be continuously produced.

The exhaust means comprises exhaust means joined to the wood raw material and an intake source communicating with the exhaust means, and the wood raw material is sucked and decompressed by the exhaust means and the intake source communicated with the exhaust means during the thermal pressure of the wood raw material. At the same time, the water vapor generated and staying in the wood raw material along with the exhaust flow from the exhaust means is diffused together with harmful chemical substances attached thereto.

In the above, heating related to the heat pressure is performed by high frequency heating, and it becomes easy to obtain a high-quality thick product.

  An embodiment of a method for producing a harmful chemical substance-reduced wood board according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating one embodiment of a hot press apparatus according to the embodiment. In the figure, 1 is a hot press which comprises a hot pressing part 2 and heats a wood raw material to which an adhesive is added to bond the wood raw material by curing the adhesive to form a plywood, particle board, fiber board or other woody material. The hot press part 2 is provided with discharge means 3 for releasing harmful chemical substances evaporated from the adhesive together with water vapor generated and retained in the wood raw material during hot press.

FIG. 2 is a partial cross-sectional view showing an embodiment of the discharge means 3 in the hot press apparatus shown in FIG. In the figure, reference numerals 21 and 22 denote an upper hot platen and a lower hot plate, respectively, and the hot press part 2 is constituted by both of them. Reference numerals 21a and 22a denote air feed paths formed in the horizontal direction on the upper heat plate 21 and the lower heat plate 22, respectively. The air pressure surfaces (the wood raw materials) in the air feed channels 21a and 22a and the heat plates 21 and 22 are respectively shown. A large number of holes 30 and 40 are formed between the contact surface and the surface. A harmful chemical substance discharging means 3 (FIG. 1) is constituted by an air feed path, a hole portion, and high-pressure air described later passing through these holes.

With the start of heat pressure, high pressure air is supplied from the air feed path 22a. This high-pressure air travels as shown by the arrows in the figure, passes through the hole 40 and reaches the board (wood raw material) B, part of which is discharged from the end of the board (wood raw material) B, and the remainder is (wood raw material) B passes through the hole 30 and travels through the air passage 21a to be discharged to the outside.

When high-pressure air is supplied together with the heat pressure and passes through the air passage on the one hot platen side and the hole as described above, the harmful chemical substances evaporated by heating the adhesive are Similarly, it is discharged to the outside, that is, to the outside of the board B together with the water vapor generated by the heat pressure.

FIG. 3 is a partial sectional view showing another embodiment of the discharging means 3 in the hot press apparatus shown in FIG. In this embodiment, the configuration of the hot pressing part is exactly the same as that shown in FIG. 2, but the discharging means 3 is slightly different. That is, in this embodiment, a negative pressure is applied to the air feed path on the side different from the air feed path to which the high-pressure air is supplied in addition to the air feed path, the hole, and the high-pressure air. The negative pressure is generated by an air suction machine connected to the air feed path. As shown in the drawing, the discharge of harmful chemical substances held in the air flow by the high-pressure air becomes extremely efficient.

FIG. 4 is a partial cross-sectional view showing still another embodiment of the discharge means 3 in the hot press apparatus shown in FIG. In this embodiment as well, the configuration of the hot pressing part is exactly the same as that shown in FIG. 2, but the discharging means 3 is slightly different. That is, in this embodiment, the discharge means 3 is constituted by the negative pressure in one of the air feed path, the hole, and the pair of holes. The negative pressure is generated by an air suction machine connected to the air feed path. Discharge of harmful chemical substances that are held in the air flow by suction as shown in the figure, one air passage, one hole, board, the other hole, the other air passage, and the outside in the order of air flow Is extremely efficient.

FIG. 5 is a partial cross-sectional side view showing an embodiment of a continuous hot press according to an embodiment of the present invention.
In the figure, 11 comprises a pair of upper and lower hot-pressing parts 12 and 12 for continuously hot-pressing the wood raw material 4 to which an adhesive has been added. This is a continuous hot press apparatus for continuously forming a fiber board or other woody material 13.

The hot pressure unit 12 includes a hot platen, a heat source, a high-pressure air supply unit and / or an exhaust unit, and continuously forms the wood material 12 while hot-pressing the wood raw material 4. Pressing high-pressure air into the wood raw material 4 and exhausting the water vapor generated inside and the harmful chemicals evaporated by the heat pressure to the outside makes it possible to obtain a wooden board with reduced harmful chemical substances while preventing puncture. ing. The configuration of the hot pressing portion is the same as that in the above-described embodiment.

In any of the above-described hot press apparatuses or wood material manufacturing methods, heating related to hot pressure is performed by high-frequency heating, which may facilitate the manufacture of thick boards.

In the wood board obtained in the above example, most of the harmful chemical substances related to the adhesive are released to the outside due to the heating of the adhesive, and the generation of harmful chemical substances is appropriately suppressed even when used in buildings etc. Yes, details will be explained in the following experiment.

  Next, a test performed for confirming the effect of the present invention will be described. In this test, a wooden board B was manufactured using the hot press apparatus shown in FIG.

Under the above-described configuration, when the wood board (wood raw material) B is hot-pressed, the operation of a vacuum pump (not shown) as a suction source sucks the wood raw material (wood board) B on the upper surface while high-pressure air. A compressor (not shown) as a source is supplied with high-pressure air. The air that is press-fitted into the wood raw material (wood board) B together with the internal water vapor and harmful chemicals is sucked into the air passage 21a that has become negative pressure by suction, and is diffused to the outside as an exhaust flow as indicated by arrows. .

The contents of the effect confirmation test are as follows.
A: For the particles used as the raw material of the wooden board, those for the heart layer (manufactured by Novapon Industry Co., Ltd.) manufactured from wooden waste were used.
B: Urea resin (UB-K16, manufactured by Oshika Co., Ltd., resin ratio 65%, viscosity 0.14 Pa · s) was used as the adhesive, and 7% (weight ratio) of the adhesive was added to the particles It was.
C: The press temperature was 190 degrees Celsius and the press time was 6 minutes.
D: The board dimensions were 30 cm × 30 cm × 1 cm, and the target board density was 0.7 g / cubic centimeter.
Then, as a comparative control, a similar wooden board was produced according to the above specifications by a conventional hot press.

The wood board obtained by the above hot press according to the example of the present invention was compared with the wood board obtained by the conventional technique, and the results shown in Tables 1 and 2 of FIG. 6 were obtained.
Table 1 shows a comparison result of formaldehyde emission (mg / L) among harmful chemical substances. Table 2 shows the comparison results of the emission rate (μg / square meter · h) of VOCs other than formaldehyde. In any table, it is clear that when forced discharge is performed, an extremely remarkable reduction effect of harmful chemical substances is obtained.

It is the structure schematic which shows one Example of a hot press. It is a partial cross section figure which shows one Example of the discharge means 3 in the hot press apparatus shown in FIG. It is a partial cross section figure which shows the other Example of the discharge means 3 in the hot press apparatus shown in FIG. It is a partial cross section figure which shows the further another Example of the discharge means 3 in the hot press apparatus shown in FIG. It is a partial cross section side view which shows one Example of the continuous hot press which concerns on this invention. It is a table | surface which shows the comparison result of an effect confirmation test.

Claims (6)

A pair of heating plates by applying or distributing an adhesive to a wood raw material comprising at least one kind of a single plate, fiber, particle, flake, strand, and strand. In addition to forming a wooden board by the hot press of a hot press, the harmful chemical substances generated by heating the adhesive are forcibly dissipated to the outside by a discharging means. Method. The method for producing a hazardous chemical substance-reduced wood board according to claim 1, wherein the hot press is a continuous hot press. 3. The method for manufacturing a wooden board with reduced harmful chemical substances according to claim 1 or 2, characterized in that a high frequency is used for the wooden raw material coated or distributed with an adhesive during hot pressing. Method. In the wood board formed by solidifying and molding a wood raw material comprising at least one aggregate of a single plate, fiber, particle, flake, strand, and strand with an adhesive, Hazardous chemical substance-reduced wood board that releases harmful chemical substances related to the adhesive to the outside by heating the adhesive. 5. The harmful chemical substance-reduced wood board according to claim 4, wherein the adhesive is heated by hot pressing of the wood board, and the harmful chemical substances generated by the heating are forcibly discharged outside the wood board. To reduce harmful chemicals wooden board. 6. The harmful chemical substance-reduced wooden board according to claim 5, wherein the hot pressing of the wooden board is performed by a hot press equipped with a discharge means forcibly dissipating harmful chemical substances generated by heating the adhesive to the outside. Characteristic wood board with reduced harmful chemicals.

Images