WO2015001702A1 - Method for manufacturing wooden board, and wooden board - Google Patents

Abstract

　A method for manufacturing a wooden board (1) in which at least the surface of a core layer (2) bonded using plant-based chips is provided with a surface layer (3) bonded using plant-based fibers or plant-based chips finer than the plant-based chips of the core layer (2), the surface layer (3) being bonded by an adhesive, wherein the method is characterized in that a petroleum-derived adhesive is used as the adhesive for bonding the plant-based chips of the core layer (2), and a plant-derived adhesive is used as the adhesive for bonding the plant-based chips or fibers of the surface layer (3).

Description

Wood board manufacturing method and wood board

The present invention relates to a method for manufacturing a wooden board and a wooden board.

In recent years, several biomass-based adhesives composed of a combination of acid and sugar have been studied as adhesives used for molding wood boards used in residential building materials such as floors, walls and doors (for example, patents) References 1 and 2).

As a feature of the adhesive composed of a combination of acid and sugar, since the adhesive component is a plant-derived component, it is carbon neutral and has a high consideration effect on the global environment.

However, adhesives consisting of a combination of acid and sugar are hardened via esterification reaction between the hydroxyl group of the vegetable chip, which is the material of the wood board, and the carboxyl group of the acid, or via a furan ring compound modified with sugar. Therefore, there is a problem that it takes time to form the wooden board.

JP 2002-361611 A WO2010-001988

General wood boards such as particle boards have a three-layer structure consisting of a surface layer, a core layer, and a surface layer. In the molding step, the surface layer is first heated by a hot plate for heating and pressurizing, and the moisture contained in the surface layer becomes high-temperature steam to become a heat medium, thereby curing the adhesive of the core layer.

In such a molding process, when the wood board to be molded is thick, it takes time to increase the temperature of the core layer, so the molding time becomes long, and there is a problem of causing adhesion inhibition if not sufficiently heated. there were.

On the other hand, in the wood board using the bagasse chip which is the residue after squeezing sugar cane as the vegetable chip of the material of the wood board, the sugar content remaining in the bagasse chip may cause mold on the surface of the wooden board or decrease the water resistance There was a problem of causing.

The present invention has been made in view of the circumstances as described above, and is a method for producing a wooden board that takes into account the global environment and has both excellent physical properties and reduced molding time, and generation of mold. It is an object to provide a wooden board that is suppressed and has water resistance.

The present invention is characterized by the following in order to solve the above problems.

That is, in the method for producing a wood board of the present invention, a plant chip or plant fiber finer than the plant chip of the core layer is applied to at least the surface of the core layer to which the plant chip is bonded with an adhesive. A method for producing a wood board in which an adhered surface layer is disposed and adhered with an adhesive, wherein a petroleum-derived adhesive is used as an adhesive for adhering the plant chip of the core layer, and the plant property of the surface layer A plant-derived adhesive is used as an adhesive for bonding chips or fibers.

Further, in this method for producing a wooden board, it is preferable that the plant-derived adhesive is an adhesive composed of a combination of acid and sugar.

Further, in this method for producing a wood board, the petroleum-derived adhesive is preferably a urea melamine adhesive or a urethane adhesive.

Further, in this method for producing a wood board, it is preferable that the vegetable chip or fiber is a bagasse chip or fiber.

In the wood board of the present invention, a plant chip or plant fiber finer than the plant chip of the core layer is adhered to at least the surface of the core layer to which the plant chip is adhered by an adhesive. A wood board having a surface layer and bonded with an adhesive, wherein the adhesive for adhering the plant chip of the core layer is an oil-derived adhesive, and the plant chip or fiber of the surface layer is bonded The adhesive is a plant-derived adhesive comprising a system in which an acid and a sugar are combined.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the wooden board which considered the global environment and made the physical strength of outstanding intensity | strength and shortening of shaping | molding time, and generation | occurrence | production of mold | fungi are suppressed, and the wooden board which has water resistance is suppressed. be able to.

It is a schematic sectional drawing of the wood board concerning embodiment of this invention.

FIG. 1 is a schematic cross-sectional view of a wooden board according to an embodiment of the present invention. When producing a wood board, chips or plant fibers (hereinafter referred to as fibers) finer than the chips of the core layer are formed on at least the surface of the core layer to which plant chips (hereinafter abbreviated as chips) are bonded with an adhesive. A surface layer is abbreviated to be adhered with an adhesive, and is adhered with an adhesive. And in the manufacturing method of the wooden board 1, the adhesive agent derived from petroleum is used as an adhesive agent which adhere | attaches the chip | tip of a core layer, and the adhesive agent derived from a plant is used as an adhesive agent which adhere | attaches the chip | tip or fiber of a surface layer.

In the wood board 1, first, plant-based materials as raw materials are crushed, and the obtained chips or fibers are screened and divided into coarse chips used for the core layer 2 and fine chips or fibers used for the surface layer 3. At this time, the average particle diameter of the fine chips used for the surface layer 3 is smaller than the average particle diameter of the coarse chips used for the core layer 2.

The average particle size is not particularly limited as long as the above conditions are satisfied. Usually, the particle size of coarse chips is about 5 to 20 mm, and the particle size of fine chips is about 1 to 5 mm.

The type of chip or fiber used as a raw material can be used without particular limitation as long as it is a chip or fiber of a plant-based material that is usually used for a wooden board. For example, coniferous trees such as pine, cedar and cypress, broad-leaved trees such as lawan, capol, and poplar, kenaf core, chips such as bagasse that is a residue after squeezing sugar cane, or fibers can be mentioned. Among these, conifers, bagasse chips or fibers can be preferably used.

In the manufacturing method of the wood board 1, a petroleum-derived adhesive is applied to the rough chips constituting the core layer 2, and a plant-derived adhesive is applied to the fine chips or fibers constituting the surface layer 3. .

As the petroleum-derived adhesive to be applied to the rough chip constituting the core layer 2, a commonly known petroleum-derived adhesive can be used, for example, urea melamine-based adhesive, phenol-based adhesive, urethane-based adhesive. Can be used.

Examples of the urea melamine adhesive include a urea resin adhesive, a melamine resin adhesive, and a UMF (urea melamine resin) adhesive. Examples of urethane adhesives include MDI (diphenylmethane diisocyanate) adhesives, TDI (tolylene diisocyanate) adhesives, MDI prepolymer adhesives, TDI prepolymer adhesives, and the like. These may be used alone or in combination of two or more.

Among these, a urea melamine adhesive UMF (urea melamine) adhesive and a urethane adhesive MDI (diphenylmethane diisocyanate) adhesive can be suitably used.

Also, a curing accelerator according to the type of petroleum-derived adhesive can be added. For example, ammonium sulfate or ammonium chloride can be used as a curing accelerator for UMF (urea melamine resin) adhesive.

As the plant-derived adhesive applied to the fine chips or fibers constituting the surface layer 3, an adhesive composed of a combination of acid and sugar can be used. As a combination of this acid and sugar, when the acid and sugar are mixed in advance, or when the fiber constituting the surface layer 3 contains sugar, the acid is supplied to the sugar to thereby generate acid on the fiber surface. And sugars in contact with each other.

Examples of the acid include polyvalent carboxylic acids such as citric acid, itaconic acid and malic acid, and organic sulfonic acids such as p-toluenesulfonic acid and benzenesulfonic acid. The polyvalent carboxylic acid and the organic sulfonic acid should be used in combination. Is preferred. Examples of the sugar include sucrose, xylose, and dextrin.

Also, a curing accelerator according to the type of plant-derived adhesive can be added, and for example, organic sulfonic acids such as p-toluenesulfonic acid can be used.

In addition, when a bagasse chip | tip is used as a material of the chip | tip which comprises the surface layer 3, it may generate | occur | produce mold | fungi or may cause water resistance fall resulting from the sugar content which remains in the bagasse after squeezing. Therefore, an adhesive consisting of a combination of a plant-derived acid and sugar is used to adhere the bagasse chip constituting the surface layer 3, thereby reacting an adhesive consisting of a combination of sugar and acid and sugar remaining in the bagasse chip. To reduce sugar content.

The sugar remaining in the bagasse chip is hydrolyzed by polyvalent carboxylic acid, which is an acid of an adhesive composed of a combination of acid and sugar, temporarily reduced in molecular weight, and then a low molecular compound having a furan ring (furan The reaction between the furan ring compounds is accelerated by a curing accelerator such as an organic sulfonic acid. For this reason, a furan ring compound is polymerized and contributes to adhesion.

In addition, the polyvalent carboxylic acid ester-bonds with the hydroxyl groups in the cellulose, hemicellulose, lignin and sugar components contained in the bagasse, contributes to the modification of the sugar content, suppresses the generation of mold and improves the water resistance.

Next, an adhesive is applied to the chips or fibers constituting the core layer 2 and the surface layer 3. The amount of the adhesive applied is preferably in the range of 0.1 to 20 parts by mass of the solid content of the adhesive when the dry mass of the raw material chips or fibers is 100 parts by mass.

Next, the chips of the core layer 2 and the chips or fibers of the surface layer 3 to which the adhesive has been applied are spread using a forming machine so that the surface layer 3, the core layer 2, and the surface layer 3 are in this order in a three-layer structure. Laminate. And after making it into a mat shape, the wooden board 1 can be obtained by temporarily pressing and heat-pressing.

The heating and pressing conditions can be appropriately set according to the size, thickness, material and the like of the wooden board 1 to be manufactured, but are usually the heating temperature of 160 to 220 ° C. and the pressure of 0.4 to 4 MPa.

As the heating and pressing method, the heating and pressing method usually used for producing a wood board can be selectively adopted. For example, a flat pressing method or a continuous pressing method using a steel belt can be mentioned. In view of the above, a continuous press method using a steel belt is preferable.

Thus, the core layer 2 and the surface layer 3 are sufficiently bonded in a short time by using a petroleum-derived adhesive for the core layer 2 and heating and pressing the surface layer 3 using a plant-derived adhesive. . When heating and pressurizing, it takes time to increase the temperature of the core layer 2 as compared to the increase of the temperature of the surface layer 3. However, since a petroleum-derived adhesive having a higher reactivity than the plant-derived adhesive is used for the core layer 2, when the adhesive strength of the surface layer 3 adhesive is increased, the adhesive of the core layer 2 Adhesive strength is also high, and both the core layer 2 and the surface layer 3 are sufficiently adhered by heating and pressing in a short time.

In the wood board 1, a surface layer 3 in which chips or fibers finer than the chip of the core layer 2 are bonded with an adhesive is disposed on at least the surface of the core layer 2 to which the chip is bonded with an adhesive. Has been. The wood board 1 is a plant-derived adhesive in which the adhesive for bonding the chip of the core layer 2 is an oil-derived adhesive, and the adhesive for bonding the chip or fiber of the surface layer 3 is a combination of acid and sugar. It is an adhesive.

Since this wood board 1 uses a plant-derived adhesive composed of a combination of acid and sugar as an adhesive for adhering the chips or fibers of the surface layer 3, the sugar content remaining on the chips or fibers of the surface layer 3 is used. It contributes to denaturation and suppresses the generation of mold and has excellent water resistance.

As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to said embodiment at all, and various changes are possible within the range which does not deviate from the summary.

For example, in the above embodiment, the chip of the core layer 2 and the chip of the surface layer 3 or the type of fiber are each one type of chip, but a plurality of types of chips can be mixed and used. In the present embodiment, the surface layer 3, the core layer 2, and the surface layer 3 have a three-layer structure. However, the core layer 2 may have a multilayer structure.

Moreover, after cooling and curing the wood board 1 formed in this way, surface polishing is performed, and a decorative veneer or a decorative sheet is bonded to the surface, whereby a building material such as a floor, a wall, or a door can be obtained. .

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

バ Bagasse and coniferous trees, which are residues after squeezing sugar cane, were cut into lengths of about 5 cm and pulverized using a pulverizer (hammer mill) to obtain bagasse chips and coniferous chips.

Next, each of these chips was divided into a coarse chip for the core layer and a fine chip for the surface layer. At this time, the average particle diameter of coarse chips was about 5 to 20 mm, and the average particle diameter of fine chips was about 1 to 5 mm.

The following UMF adhesives and MDI adhesives were used as petroleum-derived adhesives for the core layer.
UMF adhesive: Oshika Resin TB103 (solid content 64%) 100 g dissolved in ammonium chloride 1.2 g MDI adhesive: Nippon Polyurethane Wood Cure 300 (solid content 100%)
The following acid / sugar adhesive aqueous solutions were prepared as plant-derived adhesives for the surface layer.

Citric acid (manufactured by Wako Pure Chemical Industries, Ltd.) as the acid, sucrose (manufactured by Wako Pure Chemical Industries, Ltd.) as the sugar, p-toluenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as the curing accelerator, and the mixing ratio by mass ratio And citric acid: sucrose: p-toluenesulfonic acid: water = 8: 6: 2: 14.

Next, with the combinations of chips and adhesives of Examples 1 to 4 and Comparative Examples 1 to 4 shown in Table 1, the corresponding adhesives were sprayed on the surface layer and core layer chips by spraying. .

Thereafter, a surface layer chip was laminated so as to have the ratio shown in Table 1, a core layer chip was laminated thereon, and a surface layer chip was further laminated thereon to form a three-layer laminated mat. The laminated mat was pressed under the heating and pressing conditions shown in Table 1. As a result, a wood board having a thickness of 12 mm and an air-drying density of 0.6 g / cm ³ was obtained.

The wood boards of Examples 1 to 4 and Comparative Examples 1 to 4 thus prepared were subjected to an extraction test, a peel strength test, a water resistance test, a hot water resistance test, and a mold resistance test by the following methods. .
(Extraction test)
The wood board was pulverized, and the pulverized product was extracted with hot water at 90 ° C. for 3 hours.

This hot water extract is subjected to high performance liquid chromatography analysis (HPLC) under the following conditions, and the ratio of sucrose in the dry portion of the wooden board is obtained by quantifying the peak of sucrose at 90 ° C hot water extraction for 3 hours. It was.
HPLC condition column: CAPCELL PAK NH2 UG80 (4.6 mm Id × 250 mm, particle size 5 μm) manufactured by Shiseido Co., Ltd.
Eluent: acetonitrile / water = 85/15
Flow rate: 2.0 mL / min
Temperature: 40 ° C
Injection volume: 10 μL
Detector: RI detector A calibration curve was prepared using a standard sample (sucrose) as appropriate.

The extraction test was conducted for Examples 1 to 3 and Comparative Examples 1 and 3. In Comparative Example 2, an extraction test could not be performed because the core layer was not sufficiently adhered and could not be molded. In Example 4 and Comparative Example 4, softwood chips were used, and no extraction test was performed because it was considered that no sugar was present in the chips.
(Peel strength test)
A peel strength test was performed according to JIS A 5905.
(Water resistance test)
After immersing a 200 mm square sample of each wooden board in water at 20 ° C. for 24 hours, the thickness before and after the immersion was measured, and the thickness expansion coefficient was determined.
(Heat resistance test)
After immersing a 200 mm square sample of each wood board in hot water at 80 ° C. for 5 minutes, the thickness before and after the immersion was measured to determine the thickness expansion coefficient.
(Mold resistance test)
A mold resistance test was conducted in accordance with JIS Z 2911. After the mold spore solution was dropped, the solution was cultured under the conditions of 26 ° C., 99% RH, and 28 days, and visually evaluated according to the following criteria.
○: No growth Δ: Growth of less than 1/3 of the test area ×: Growth of 1/3 or more of the test area These results are shown in Table 1.

 

 

From Table 1, in the extraction tests of Examples 1 to 4, sucrose was not detected from the HPLC measurement and was below the measurement limit (ND), and was substantially 0% by mass in the dry matter of the wooden board. there were. Further, as agreed with this result, no mold growth was observed in the mold resistance test. Moreover, the results of peel strength, water resistance test and hot water resistance test were also excellent overall.

In contrast, in Comparative Example 1 where bagasse was used for the surface layer and petroleum-derived adhesive was used as the surface layer adhesive, sucrose extraction was observed in the extraction test, and mold growth was observed in the mold resistance test. Was recognized.

Further, in Comparative Example 2 in which a plant-derived adhesive was used as the core layer adhesive, the core layer was not sufficiently bonded and could not be molded.

In Comparative Example 3, in which the heating condition of Comparative Example 2 was set to 12 minutes, each measurement result was equivalent to that of Examples 1 to 4, but the heating time was three times that of Examples 1 to 4, It was confirmed that it must be set very long.

Furthermore, in Comparative Example 4 in which a softwood chip was used for the surface layer and a petroleum-derived adhesive was used as the surface layer adhesive, mold growth was observed in the mold resistance test.

From the above results, according to the method for producing a wooden board of the present invention using a petroleum-derived adhesive as an adhesive for the core layer and a plant-derived adhesive as an adhesive for the surface layer, generation of mold and adhesion It was confirmed that inhibition and reduction in water resistance can be suppressed.

1 Wood board 2 Core layer 3 Surface layer

Claims (5)

A surface layer in which a vegetable chip or plant fiber finer than the vegetable chip of the core layer is adhered to at least the surface of the core layer to which the vegetable chip is adhered with an adhesive is disposed, and the adhesive is used. A method for producing a wood board to be bonded, wherein an adhesive derived from petroleum is used as an adhesive for bonding the plant chip of the core layer, and a plant-derived adhesive as an adhesive for bonding the plant chip or fiber of the surface layer. A method for producing a wooden board, characterized by using an adhesive. The method for producing a wood board according to claim 1, wherein the plant-derived adhesive is an adhesive composed of a combination of acid and sugar. The method for producing a wood board according to claim 1 or 2, wherein the petroleum-derived adhesive is a urea melamine adhesive or a urethane adhesive. The method for producing a wood board according to any one of claims 1 to 3, wherein the plant chip or fiber is a bagasse chip or fiber. At least the surface of the core layer to which the vegetable chip is bonded with an adhesive is provided with a surface layer in which a vegetable chip or plant fiber finer than the plant chip of the core layer is bonded with an adhesive, A glued wood board, wherein the adhesive for adhering the vegetable chip of the core layer is an oil-derived adhesive, and the adhesive for adhering the vegetable chip or fiber of the surface layer is a combination of acid and sugar A woody board characterized by being an adhesive derived from a plant consisting of the same system.

Images