JP2007331286A - Method of manufacturing woody board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a woody board made from a recycled woody chip or recycled woody fiber as a main raw material, passing a severely regulated value of a formaldehyde amount diffused from the products, that is, regulated by a building code, for reducing a production cost on using an MDI type compound as an adhesive and for giving an improving effect for the earth environment. <P>SOLUTION: The manufacturing method of the woody board reducing global environmental load, which is formed by applying a powdery adhesive comprising mixing a powdery additive which is originated from a vegetable source selected from the group consisting of vegetable proteins being hardly soluble nor insoluble in water, and one or more selected from the group consisting of a vegetable carbohydrate or its derivatives being hardly soluble nor insoluble in water and having at least one amino group in one molecule, in a ratio of 1-40 pts.wt. per a liquid compound comprising MDI series compound as a main component of 100 pts.wt. to the woody piece or woody fiber, and then by heating, pressing and forming it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wood board improved in consideration of environmental protection. More specifically, it is obtained by adding a powder material derived from natural resources to a diphenylmethane diisocyanate compound or a prepolymer thereof (hereinafter referred to as an MDI compound) to a wood piece or wood fiber obtained from wood or recycled wood. The present invention relates to a method of manufacturing a wood board with reduced burden on the global environment and living environment by using an adhesive as a binder.

  Conventionally, wooden boards such as particle boards and fiberboards are made of recycled wood such as wood or house demolition materials in small pieces or fibers, sprayed with a formaldehyde resin adhesive such as urea resin or phenol resin, and heated. Manufactured by a pressure forming method. Particleboard is a wood board that is made by applying adhesive to a finely cut chip of wood and then heat-pressing it. It can be processed freely in thickness and size compared to natural materials such as wood. It is possible to do it, and it is characterized by less madness and warping.

  In recent years, for the purpose of reducing the amount of formaldehyde emitted from the wooden board, a method of manufacturing a wooden board using an MDI compound as an adhesive instead of a formaldehyde resin adhesive such as urea resin or phenol resin has been performed. . In addition, when the building standards law was revised in July 2003, the indoor concentration of formaldehyde was strictly regulated, so the regulation of the amount of formaldehyde released from building materials such as wooden boards became strict, and when wooden boards were molded Non-formaldehyde resin systems are increasingly used as adhesives.

However, since MDI compounds are more expensive than formaldehyde resin adhesives, particle boards, which are a type of wood board, use phenol resin adhesives with a relatively low formaldehyde emission as the binder for the surface layer. In general, a particle board manufacturing method using an isocyanate compound as a binder only in the core layer is performed (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 11-34017 (Claim 1, FIG. 1)

  In general, wood chips or wood fibers used for wood boards are made of wood waste, used plywood waste, waste pallets, and houses that are partly or most of the raw material discharged from the wood industry such as plywood. It uses so-called recycled wood chips and recycled wood fibers obtained from wood materials that are already used and discarded, such as demolition materials, and contributes greatly to the reduction of wood waste discharged as industrial waste.

  However, when an inventory analysis was conducted to calculate the total energy used in the board production, emissions of carbon dioxide, NOx, SOx, etc. and to investigate the degree of impact on the global environment, wood chips obtained from logs When life cycle assessment (LCA) analysis is performed in comparison with the case of producing wood boards using wood fibers, the influence of the adhesive used becomes extremely large, and recycled wood chips and recycled wood fibers are used as raw materials. It became clear that there was little effect on global environment improvement by this. In addition, wooden boards using recycled wood chips and recycled wood fibers as raw materials already contain formaldehyde in the recycled wood chips and recycled wood fibers used as raw materials. There is a problem that it is difficult to pass the prescribed regulation value of formaldehyde emission amount, and when producing this kind of wood board, it is necessary to use MDI compound which is non-formaldehyde adhesive It was the actual situation. However, this adhesive is more expensive than a formaldehyde adhesive, and there is a problem that the production cost of the board increases. In particular, when MDI compounds are used as adhesives compared to the use of formaldehyde resin adhesives such as urea resins and phenolic resins, the result of LCA analysis reveals that the total energy consumption increases. became.

  The object of the present invention is that a wooden board manufactured using recycled wood chips and recycled wood fibers as a main raw material, the amount of formaldehyde released from the product passes the strict regulation values regulated by the Building Standards Law, and MDI compounds are used. An object of the present invention is to provide a method for manufacturing a wooden board that reduces the production cost when used for an adhesive and has an effect of improving the global environment.

The invention according to claim 1 is based on 100 parts by weight of a liquid compound containing an MDI compound as a main component, a vegetable protein that is hardly soluble or insoluble in water, and one or more in one molecule that is hardly soluble or insoluble in water. An adhesive comprising 1 to 40 parts by weight of an additive powder derived from one or more plant resources selected from the group consisting of plant carbohydrates having amino groups and derivatives of the carbohydrates A wood board manufacturing method characterized by obtaining a wood board with reduced global environmental load by applying to a wood piece or wood fiber and heating and pressing.
In the invention according to claim 1, the additive powder mixed with the liquid compound containing the MDI compound as a main component is derived from plant resources and contains a large amount of carbon components. By adding the above additive powder to a liquid compound containing an MDI compound as the main component, this addition of formaldehyde contained in the wood board produced using wood chips and wood fibers obtained from wood waste as the main raw material Since the agent powder is absorbed and bonded, the amount of formaldehyde emitted from the produced wooden board can be reduced. In addition, since the additive powder is bonded with the MDI compound by a mild chemical reaction, it is possible to prevent the adhesive from penetrating into the wood and increase the adhesive strength of the wood board. In addition, the amount of MDI compounds derived from petroleum resources can be reduced by mixing the additive powder with the adhesive at a predetermined ratio, causing the global carbon cycle and global warming. Carbon dioxide emissions can be reduced. Therefore, the production method of the present invention is environmentally friendly and has an effect of improving the global environment. Furthermore, the effect of greatly reducing the cost of the adhesive, which is a factor that increases the manufacturing cost of the wooden board, is also remarkable.

The invention according to claim 2 is the method according to claim 1, wherein the vegetable protein hardly soluble or insoluble in water is high-temperature defatted soybean meal.
In the invention according to claim 2, the high-temperature defatted soybean cake, in which the protein is heat-denatured and hardly dissolved in water, has a small increase in the viscosity of the adhesive even when added in large amounts to the MDI compound, An adhesive prepared by mixing this high-temperature defatted soybean cake on the surface of a wood chip or wood fiber can be uniformly sprayed or sprayed. In addition, since the amino group of the high-temperature defatted soybean meal easily reacts with formaldehyde, it binds to free formaldehyde present in the wood material, and has the effect of reducing the amount of formaldehyde emitted. In addition, high-temperature defatted soybean meal has hydroxyl groups and amino groups that easily react with isocyanate groups, so it acts as a filler and binds firmly to MDI compounds, and is used as an adhesive inside wooden materials such as wood chips and wood fibers. To prevent penetration. Therefore, even if the amount of high-temperature defatted soybean meal added to the MDI-based compound increases, the decrease in bending strength, peel strength, and water-resistant adhesion performance of the obtained wooden board is small. Since high-temperature defatted soybean meal can be mixed in a large amount with MDI-based compounds, the cost of the adhesive can be reduced accordingly, and the effect of improving the global environment can be achieved.

The invention according to claim 3 is the invention according to claim 1, and is a method for producing a wooden board in which the vegetable protein hardly soluble or insoluble in water is corn protein.
In the invention according to claim 3, by adding corn gluten powder composed of prolamin protein that is hardly soluble in water to an MDI compound and using it as an adhesive, the protein is heat denatured and hardly dissolved in water. It has the same effect as the high temperature defatted soybean meal.

The invention according to claim 4 is the invention according to claim 1, wherein the vegetable carbohydrate is one that is hardly soluble or insoluble in water and has one or more amino groups in one molecule, which is a carbamic acid-modified starch. It is a manufacturing method.
In the invention according to claim 4, the carbamic acid-modified starch is less soluble or insoluble in water than the unmodified starch, and is hardly dissolved in alkaline water, and has an amino group in the molecule and has formaldehyde or isocyanate. This is because it has the property of easily reacting with. Even if a large amount of carbamic acid-modified starch having such properties is mixed with the MDI compound, the carbamic acid-modified starch does not dissolve and increase the viscosity of the adhesive. Since it is extremely few, it can be used without any trouble when an adhesive mixed with this carbamic acid-modified starch is applied to the surface of a wood chip or wood fiber by spraying, compared with an adhesive without adding carbamic acid-modified starch. Such characteristics are remarkable as compared with the case where high temperature defatted soybean meal and corn protein are added and mixed, and further, the formaldehyde collection effect is also greater than that of high temperature defatted soybean meal and corn protein. Therefore, carbamic acid-modified starch derived from plant resources is an ideal filler in the production of wooden boards, and adhesives with carbamic acid-modified starch added to MDI compounds are used for wood such as used plywood and wooden boards. It is most suitable as an adhesive for wooden boards that recycle waste, which reduces the cost of the adhesive and contributes to the reduction of carbon dioxide in the atmosphere. This production method using carbamic acid-modified starch is environmentally friendly and has an effect of improving the global environment.

  The method for producing a wooden board of the present invention comprises a liquid compound mainly composed of an MDI compound, a plant protein that is hardly soluble or insoluble in water, and that is hardly soluble or insoluble in water and contains one or more molecules in one molecule. A small piece of wood or a fiber comprising an adhesive prepared by mixing an additive powder derived from one or more plant resources selected from the group consisting of a vegetable carbohydrate having an amino group and a derivative of the carbohydrate at a predetermined ratio It is characterized in that it is applied to and heated and pressed. All of the additive powders mixed with a liquid compound containing an MDI-based compound as a main component are derived from plant resources and contain a large amount of carbon components. By adding the above additive powder to a liquid compound containing an MDI compound as the main component, this addition of formaldehyde contained in the wood board produced using wood chips and wood fibers obtained from wood waste as the main raw material Since the agent powder is absorbed and bonded, the amount of formaldehyde emitted from the produced wooden board can be reduced. In addition, since the additive powder is bonded with the MDI compound by a mild chemical reaction, it is possible to prevent the adhesive from penetrating into the wood and increase the adhesive strength of the wood board. In addition, the amount of MDI compounds derived from petroleum resources can be reduced by mixing the additive powder with the adhesive at a predetermined ratio, causing the global carbon cycle and global warming. Carbon dioxide emissions can be reduced. Therefore, the production method of the present invention is environmentally friendly and has an effect of improving the global environment. Furthermore, the effect of greatly reducing the cost of the adhesive, which is a factor that increases the manufacturing cost of the wooden board, is also remarkable.

Next, the best mode for carrying out the present invention will be described.
Conventionally, a wood board is a hot board in which an adhesive is sprayed onto a wood piece or wood fiber in an amount of 2 to 25% in terms of solid content, and then laminated in a flat mat shape and kept at a hot plate temperature of 120 to 250 ° C. It is obtained by inserting into a press and applying a pressure of 0.5 to 5 MPa at a rate of 3 to 60 seconds per 1 mm of board thickness and pressing and molding. At that time, an amino resin such as a urea resin, a melamine / urea resin, or a formaldehyde resin using formaldehyde such as a phenol resin as a part of the raw material is usually used as an adhesive.

  However, the wood board product obtained in this way has a problem in that formaldehyde gas is diffused and the indoor air is polluted when the product is used. The concentration of formaldehyde gas to be emitted has become strictly regulated. For products of the grade classification “F ☆☆☆☆”, where the amount of formaldehyde emitted from the product is particularly strict, even if an amino resin adhesive is used as an adhesive, it does not meet the regulatory value. In general, MDI-based compounds are used for adhesives used in products that meet the grade classification. However, since MDI-based compounds are expensive, methods such as using a phenol resin adhesive in the surface layer portion and the like have been adopted to reduce the amount of MDI-based compounds used. Moreover, in order to reduce the cost of the MDI-based compound adhesive, an inorganic filler such as calcium carbonate is added, but this increases the density of the board and damages the cutting blade. There wasn't.

  As a result of diligent research to solve the above problems, the present inventors have found that MDI compounds are hardly soluble or insoluble in water, hardly soluble or insoluble in water, and one per molecule. It is found that a desired effect can be obtained by mixing one or more plant powder-derived additive powders selected from the group consisting of carbohydrates having one or more amino groups and derivatives of the carbohydrates, The present invention has been completed.

  In the method for producing a wood board of the present invention, 100 parts by weight of a liquid compound containing an MDI compound as a main component, a vegetable protein that is hardly soluble or insoluble in water, and hardly soluble or insoluble in water, one per molecule. Adhesion formed by mixing 1 to 40 parts by weight of an additive powder derived from one or more plant resources selected from the group consisting of plant carbohydrates having at least one amino group and derivatives of the carbohydrates It is characterized in that a wood board with reduced global environmental load is obtained by applying an agent to a wood piece or wood fiber and heating and pressing.

  All of the additive powders mixed with a liquid compound containing an MDI-based compound as a main component are derived from plant resources and contain a large amount of carbon components. By adding the above additive powder to a liquid compound containing an MDI compound as the main component, this addition of formaldehyde contained in the wood board produced using wood chips and wood fibers obtained from wood waste as the main raw material Since the agent powder is absorbed and bonded, the amount of formaldehyde emitted from the produced wooden board can be reduced. In addition, since the above additive powder is bonded to the MDI compound by a mild chemical reaction, it prevents the penetration of the adhesive into the wood and increases the cross-linking density, thereby increasing the adhesive strength of the wood board. The effect of improving the water-resistant adhesion performance is obtained. It can be thought of as a reactive filler, and this effect is different from bulking agents that dissolve or swell in water, such as commonly used flour and low-temperature defatted soybeans, and suppresses rapid reaction with adhesives. Therefore, it is possible to add a large amount to the MDI-based compound adhesive, and a feature that moderates a decrease in water resistance of the wooden board due to the large amount addition is recognized.

  Such an effect is obtained regardless of the shape of the chip, flakes, sticks, etc. of the wood pieces to be used, particle board, flake board, stick board, and strand board (OSB; Oriented) The same effect can be obtained with any of the wooden boards such as Strand Board), MDF (Midium Density Fiberboard) or HDF (High Density Fiberboard) using a wood fiber, hard board or insulation board.

  In addition, since amino groups easily react with formaldehyde, binding to free formaldehyde present inside the wood material also has an effect of reducing the amount of formaldehyde emitted from the wood board product produced by the method of the present invention. . This effect is particularly noticeable in the case of carbamic acid ester starch, using a formaldehyde resin adhesive such as phenol resin or melamine urea resin for the surface layer of the wooden board, and using the adhesive paste of the present invention for the inner layer. Even in this case, the effect is recognized. However, when added to formaldehyde-based resin adhesive, the amount that can be added is about 1 to 10 parts by weight with respect to 100 parts by weight of the adhesive. As a result, the effect of the present invention is halved.

  Furthermore, when these amino acid-containing protein and starch derivative powders are mixed with MDI compounds, the reaction progresses and powders differ from conventional bulking agents such as wheat flour and low-temperature defatted soybeans. The increase in viscosity of the adhesive paste due to the swelling of the particles with water is gradual, and no use in spray coating is observed. Therefore, there is no problem such as a decrease in productivity.

  In addition, the amount of MDI compounds derived from petroleum resources can be reduced by mixing the additive powder with the adhesive at a predetermined ratio, causing the global carbon cycle and global warming. Carbon dioxide emissions can be reduced. Therefore, the production method of the present invention is environmentally friendly and has an effect of improving the global environment. Furthermore, the effect of greatly reducing the cost of the adhesive, which is a factor that increases the manufacturing cost of the wooden board, is also remarkable.

  As the wood piece or wood fiber used in the method for producing a wood board of the present invention, it is preferable to use a part or most of the recycled wood piece or the recycled wood fiber obtained from the wood waste. Not only materials, but also wood chips or wood fibers obtained from logs and thinned timbers, forest residue, wood demolition materials such as pillars and beams. Further, the shape of the wood pieces or wood fibers is not particularly limited.

  The additive powder is added in an amount of 1 to 40 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the liquid compound containing the MDI compound as a main component. If the ratio of the additive powder is within the above range, the effect of reducing the amount of formaldehyde emission and improving the adhesion performance can be obtained. In addition, when the ratio of the additive powder is less than 1 part by weight, a desired effect cannot be obtained, and when the ratio of the additive powder exceeds 40 parts by weight, the water-resistant adhesion performance is significantly deteriorated.

  Examples of vegetable proteins that are hardly soluble or insoluble in water include high-temperature defatted soybean meal and corn protein. High-temperature defatted soybean meal is discharged in large quantities during the production of edible oil, and the price is also low, so the production cost of the wooden board can be greatly reduced. High-temperature defatted soybean meal is a protein that has been heat-denatured and is difficult to dissolve in water, and even when added and mixed in large amounts with MDI compounds, the viscosity of the adhesive is small, so wood chips and wood An adhesive in which the high-temperature defatted soybean cake is mixed on the surface of the fiber can be uniformly sprayed or sprayed by spraying. In addition, since the amino group of the high-temperature defatted soybean meal easily reacts with formaldehyde, it binds to free formaldehyde present in the wood material, and has the effect of reducing the amount of formaldehyde emitted. In addition, high-temperature defatted soybean meal has hydroxyl groups and amino groups that easily react with isocyanate groups, so it acts as a filler and binds firmly to MDI compounds, and is used as an adhesive inside wooden materials such as wood chips and wood fibers. To prevent penetration. Therefore, even if the amount of high-temperature defatted soybean meal added to the MDI-based compound increases, the decrease in bending strength, peel strength, and water-resistant adhesion performance of the obtained wooden board is small. Since high temperature defatted soybean meal can be mixed in a large amount with MDI-based compounds, the cost of the adhesive can be reduced accordingly, and it has the effect of improving the global environment.

  Corn protein is corn gluten powder consisting of prolamin protein, which is sparingly soluble in water, mixed with MDI compounds and used as an adhesive, so that the protein is heat-denatured so that it is difficult to dissolve in water. Has the same effect as soybean meal.

  Examples of vegetable carbohydrates that are hardly soluble or insoluble in water and have one or more amino groups in one molecule include carbamic acid-modified starch. A method for producing a carbamic acid-modified starch is as follows. First, 0.5 kg per 1 mol of glucose unit is added to plant starch such as rice, wheat, corn, millet, millet, millet, coriander (Takaki or sorghum), potato, sweet potato, tapioca. Mix 4 moles of urea and mix more uniformly while grinding. After mixing, the obtained mixture is heated at a temperature of 100 to 200 ° C. for 0.5 to 5 hours. By this heating, urea causes a deammonification reaction to become carbamic acid, and further carbamic acid undergoes an esterification reaction with a hydroxyl group in glucose to produce a modified starch. The resulting modified starch is cooled and then ground to a size of 60 to 200 mesh to obtain a carbamic acid-modified starch.

  Since there are three hydroxyl groups that can be esterified among the hydroxyl groups of glucose that constitutes starch, theoretically no further esterification reaction occurs even if urea exceeding 3 mol is added. However, since deammonia reaction does not occur and there remains unreacted urea, the upper limit of the amount of urea added to the plant starch was set to 4 mol. In addition, even if urea exceeding 4 mol is added, it remains in the starch in the form of free urea, so there is no effect. Further, when the amount of urea added to the plant starch is less than 0.5 mol, the water resistance improvement effect and formaldehyde absorption effect to the extent expected by the production method of the present invention are not observed.

  The carbamic acid-modified starch thus obtained is less soluble or insoluble in water than unmodified starch and has a property that it is difficult to dissolve even in alkaline water. It also has the property of having an amino group in the molecule and easily reacting with formaldehyde and isocyanate. Even if a large amount of carbamic acid-modified starch is mixed with a formaldehyde resin adhesive or MDI compound, the carbamic acid-modified starch does not dissolve and increase the viscosity of the adhesive. Therefore, when an adhesive mixed with this carbamic acid-modified starch is applied to the surface of a wood chip or wood fiber by spraying, the adhesive can be used without any trouble as compared with an adhesive without adding carbamic acid-modified starch. Such characteristics are remarkable as compared with the case where high temperature defatted soybean meal and corn protein are added and mixed, and further, the formaldehyde collection effect is also greater than that of high temperature defatted soybean meal and corn protein. Therefore, carbamic acid-modified starch derived from plant resources is an ideal filler in the production of wooden boards, and adhesives with carbamic acid-modified starch added to MDI compounds are used for wood such as used plywood and wooden boards. It is most suitable as an adhesive for wooden boards that recycle waste, which reduces the cost of the adhesive and contributes to the reduction of carbon dioxide in the atmosphere. This production method using carbamic acid-modified starch is environmentally friendly and has an effect of improving the global environment.

  In the production method of the present invention, known conditions can be applied as conditions for forming the wood chips or wood fibers into boards. For example, an adhesive in which an additive powder is mixed in a desired ratio with respect to an MDI-based compound is such that the adhesive solid content is in a ratio of 2 to 25% with respect to the weight of the all dry chips or all dry fibers Apply evenly on wood chips by spraying or spraying. After spray application of the adhesive to the chip, the chip is placed on a conveying plate or belt and deposited in a mat shape, and then the formed mat is inserted into a hot press maintained at 120 to 250 ° C. A wood board having an arbitrary thickness and an arbitrary density can be obtained by applying a pressure of 5 MPa and performing heat-press molding for 3 to 60 seconds, preferably 8 to 15 seconds, per 1 mm of the board thickness to be formed.

Next, examples of the present invention will be described in detail together with comparative examples.
<Examples 1-4, Comparative Example 1>
First, a cedar semi-flake chip having an average thickness of 0.7 mm, an average of about 12 mm in the length direction, an average of about 3 mm in the width direction, and an average moisture content of 8% was prepared as a small piece of wood.
Next, with respect to 100 parts by weight of polymeric MDI (manufactured by Nippon Polyurethane Industry Co., Ltd .; WC-230), 10, 20, 30, and 40 parts by weight of carbamic acid-modified starch prepared as described below were added and mixed. Prepared. The prototype carbamic acid-modified starch is made from milled rice flour and brown rice flour as plant starch, mixed with urea at a ratio of 1 mol per mol of glucose unit, and mixed uniformly while grinding. The mixture is heated at a temperature of 150 ° C. for 3 hours to cause an esterification reaction, and the product is pulverized to a size of 60 to 200 mesh.

Next, these prepared adhesives were spray-coated at a rate of 7.5% based on the total dry weight of the chip, and the coated chips of Examples 1 to 4 were obtained. Similarly, an adhesive composed of only polymeric MDI as a comparison object was spray-coated at a rate of 7.5% per total dry weight of the chip, and this was used as the coated chip of Comparative Example 1. After spraying the adhesive onto the chip, the chip was placed on a 40 mm × 40 mm aluminum caul plate to form a mat with a uniform thickness. The formed mat was inserted into a hot press maintained at a hot plate temperature of 180 ° C., and a pressure of 30 kg / cm ² (about 2.94 MPa) was applied, followed by heating and pressing for 3 minutes. After molding, the sample was taken out from the hot press to obtain a total of 15 test particle boards each having a thickness of 10 mm and a density of 0.6 g / cm ³ .

  The performance of the test particle board obtained in Examples 1 to 4 and Comparative Example 1 was tested by the test method specified in JIS A 5908. The results for the normal bending strength (modulus of rupture), wet bending B test, peel strength, water absorption thickness swelling rate and water absorption rate are shown in FIGS. The results of formaldehyde emission are shown in Table 1 below.

As is clear from Table 1, the amount of formaldehyde emitted tended to decrease as the addition rate of carbamic acid-modified starch increased.
Moreover, from each performance test result of FIGS. 1-3, it was shown that there is no big performance change until the addition amount of the carbamic acid modified starch to polymeric MDI is up to 40 parts by weight.

<Examples 5 to 7, Comparative Examples 2 and 3>
First, a chip using a recycled chip was prepared. This chip was obtained from a factory that manufactures particle boards using recycled chips obtained from woody waste such as plywood waste and used pallets.
Next, an adhesive was prepared by adding and mixing a wax emulsion to 3% with respect to the phenol resin adhesive (in-house product), and the adhesive was spray applied so that the grease content of the chip was 13%. The thing was made into the chip | tip for surface layers.

Next, with respect to 100 parts by weight of polymeric MDI (manufactured by Nippon Polyurethane Industry Co., Ltd .; MR-200), the same carbamic acid-modified starch, high-temperature defatted soybean cake (manufactured by J Oil Co., Ltd .; Soypro) and corn gluten powder (manufactured by Nippon Cornstarch) were mixed in an amount of 20 parts by weight to prepare an adhesive. These prepared adhesives were spray-applied at a rate of 5% based on the total dry weight of the chip, which was used as the core layer chip of Examples 5-7. Similarly, as a comparative control, an adhesive composed only of polymeric MDI was spray-coated at a ratio of 5% and 4% based on the total dry weight of the chip, respectively, and used as the core layer chip of Comparative Examples 2 and 3.
Next, the surface layer chips prepared in advance and the core layer chips of Examples 5 to 7 and Comparative Examples 2 and 3 were sprayed onto a 40 mm × 40 mm aluminum call plate in a ratio of 4 to 6. A mat having a uniform thickness was formed. The formed mat was inserted into a hot press maintained at a hot plate temperature of 220 ℃, 30kg / cm ² 170 sec by applying a pressure (about 2.94 MPa), then 20 kg / cm ² pressure (about 1.96 MPa) In addition, a pressure of 10 kg / cm ² (about 0.98 MPa) was further applied for 30 seconds, followed by heating and pressing for 15 seconds. After molding, the sample was taken out from the hot press to obtain a total of 15 test particle boards each having a thickness of 20 mm and a density of 0.75 g / cm ³ .

  The performance of the test particle board obtained in Examples 5 to 7 and Comparative Examples 2 and 3 was tested by the test method specified in JIS A 5908. Table 2 shows the results of the normal bending strength, the bending B test when wet, the peel strength, the water absorption thickness swelling rate, the water absorption rate, and the formaldehyde emission amount. Table 3 shows the results of changes in spray performance over time.

  As is clear from Table 2, when the performance tests for the particle boards of Examples 5 to 7 and Comparative Example 2 were compared, no significant change was found in the performance of the particle board. From this result, it was confirmed that the particle board can be used practically without problems even when additives such as carbamic acid-modified starch, high-temperature defatted soybean meal and corn gluten powder are added to the polymeric MDI. Moreover, when the formaldehyde emission amount of Examples 5-7 and Comparative Example 2 was compared, it was found that the particle board of Examples 5-7 had an effect of reducing the formaldehyde emission amount. In particular, Example 5 in which carbamic acid-modified starch was used as an additive resulted in a large effect of reducing formaldehyde emission. Since the particle board of Examples 5 to 7 manufactured using the polymeric MDI mixed solution mixed with the additive is spray-coated in an amount equivalent to 5% with respect to the chip weight, the substantial fat content of the polymeric MDI is about 4%. Therefore, when Examples 5 to 7 were compared with Comparative Example 3 in which only MDI was applied at a ratio of 4% with respect to the core layer chip, the amount of formaldehyde emitted was similar to that in Example 7 and Comparative Example 3. However, Examples 5 and 6 had a lower emission amount than Comparative Example 3. Moreover, since the board performance of Comparative Example 3 is lower than that of Examples 5 to 7 in the other performances of the particle board, the desired addition can be obtained from this result even when the polymeric MDI is used at the same level. It was confirmed that there was an enhancing effect by adding the agent.

  Further, as is apparent from Table 3, the carbamic acid-modified starch of Example 5 has no change in the spray coating performance for a long time after being added to the polymeric MDI, and the mixed solution is stable, and can be used as an adhesive mixed solution. A result with high use time was obtained. The high-temperature defatted soybean meal of Example 6 can be sprayed uniformly immediately after mixing as in Comparative Examples 2 and 3 using only polymeric MDI, and can be sufficiently sprayed even after 2 hours of standing. there were. Further, after 3 hours of standing, a slight increase in viscosity was observed, but it was possible to spray sufficiently for the amount actually used. The corn gluten powder of Example 7 can be sprayed uniformly immediately after mixing, as in Comparative Examples 2 and 3 using only polymeric MDI, and can be sufficiently used for spraying even after 3 hours of standing. Met.

<Examples 8 and 9, Comparative Example 4>
First, a chip using a recycled chip was prepared. This chip was obtained from a factory that manufactures particle boards using recycled chips obtained from woody waste such as plywood waste and used pallets.
Next, an adhesive was prepared by adding and mixing a wax emulsion to 3% with respect to the phenol resin adhesive (in-house product), and the adhesive was spray applied so that the grease content of the chip was 13%. The thing was made into the chip | tip for surface layers.

Next, with respect to 100 parts by weight of polymeric MDI (manufactured by Nippon Polyurethane Industry; MR-200), the same carbamic acid-modified starch and high-temperature defatted soybean meal (manufactured by J Oil; A total of 20 parts by weight of Soypro) was mixed to prepare an adhesive. Similarly, with respect to 100 parts by weight of polymeric MDI (manufactured by Nippon Polyurethane Industry Co., Ltd .; MR-200), the same carbamic acid-modified starch and corn gluten powder (manufactured by Nippon Corn Starch Co., Ltd.) as those prepared in Example 1 described above were used. A total of 20 parts by weight of 10 parts by weight was mixed to prepare an adhesive. These prepared adhesives were spray-coated at a rate of 5% with respect to the total dry weight of the chip, and the core layer chip of Examples 8 and 9 was obtained. Similarly, as a comparative control, an adhesive composed only of polymeric MDI was spray-coated at a rate of 5% with respect to the total dry weight of the chip, and this was used as the core layer chip of Comparative Example 4.
Next, the surface layer chips prepared in advance and the core layer chips of Examples 8 and 9 and Comparative Example 4 were sprayed onto a 40 mm × 40 mm aluminum call plate so as to have a thickness ratio of 4 to 6, and the thickness was thereby increased Formed a uniform mat. The molded mat and inserted into a hot press maintained at a hot plate temperature of 220 ℃, 30kg / cm ² 170 sec by applying a pressure (about 2.94 MPa), then 20 kg / cm ² pressure (about 1.96 MPa) In addition, a pressure of 10 kg / cm ² (about 0.98 MPa) was further applied for 30 seconds, followed by heating and pressing for 15 seconds. After molding, the sample was taken out from the hot press to obtain a total of 15 test particle boards each having a thickness of 20 mm and a density of 0.75 g / cm ³ .

  The performance of the test particle board obtained in Examples 8 and 9 and Comparative Example 4 was tested by the test method specified in JIS A 5908. Table 4 shows the results for the normal bending strength, the bending B test when wet, the peel strength, the water absorption thickness swelling rate, the water absorption rate, and the formaldehyde emission amount.

  As can be seen from Table 4, in Examples 8 and 9, an adhesive prepared by mixing carbamic acid-modified starch and high-temperature defatted soybean meal or carbamic acid-modified starch and corn gluten powder in polymeric MDI was used as an additive. It was revealed that the above additives can be mixed and used at an arbitrary ratio, in comparison with the performance of Comparative Example 4 using only polymeric MDI as an adhesive. High-temperature defatted soybean meal is a large amount of edible oil produced during the production of edible oil, and its price is low. Therefore, by adding carbamic acid-modified starch, etc. in any proportion to this, the cost of the additive Can be prepared. At the same time, as a result of inventory analysis, an isocyanate compound resin (Junaki Hattori; No. 22), which has a higher carbon dioxide emission and environmental load than the formaldehyde resin adhesives such as melamine urea resin and phenol resin by the method of the present invention. It is possible to add an additive derived from a plant resource that absorbs and fixes carbon dioxide gas to the collection of symposiums of the recycled wood board / wood composite symposium, p49 (2006)), and the environment can be improved accordingly.

The figure which shows the relationship between normal-state bending strength and a carbamic-acid modified starch addition rate. The figure which shows the relationship between peeling strength and a carbamic-acid modified starch addition rate. The figure which shows the relationship between a water absorption thickness swelling rate and a water absorption rate, and a carbamic-acid modified starch addition rate.

Claims (4)

  100 parts by weight of a liquid compound composed mainly of a diphenylmethane diisocyanate compound, a plant protein that is sparingly soluble or insoluble in water, and that is sparingly soluble or insoluble in water and has one or more amino groups in one molecule An adhesive prepared by mixing 1 to 40 parts by weight of an additive powder derived from one or more plant resources selected from the group consisting of a carbohydrate and a derivative of the carbohydrate is applied to a wooden piece or wood fiber. A method for producing a wooden board, characterized by obtaining a wooden board with reduced environmental burden by heating and pressing.   The method for producing a wooden board according to claim 1, wherein the water-insoluble or insoluble vegetable protein is high-temperature defatted soybean meal.   The method for producing a woody board according to claim 1, wherein the vegetable protein hardly soluble or insoluble in water is corn protein. The method for producing a wooden board according to claim 1, wherein the vegetable carbohydrate which is hardly soluble or insoluble in water and has one or more amino groups in one molecule is a carbamic acid-modified starch.

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