JP2012045789A - Method of manufacturing ligneous decorative plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a ligneous decorative plate that reduces warping generated when a woody fiberboard and a surface decoration material are hot-pressed by an aqueous adhesive.SOLUTION: The method of manufacturing the ligneous decorative plate 1 integrally laminates the surface decoration material 5 on a surface of a composite 4 having the woody fiberboard 2 on its surface, wherein an isocyanate compound is applied and impregnated on a surface of the woody fiberboard 2 including a water repellent agent, and after curing process, an aqueous adhesive is applied to the surface of the woody fiberboard 2 and the surface decoration material 5 is hot-pressed.

Description

  The present invention relates to a method for manufacturing a wooden decorative board used for interior building materials and the like.

  2. Description of the Related Art Conventionally, there is known a wooden decorative board in which a surface decorative material is laminated and integrated on the surface of a wooden fiber board or a wooden fiber board composite material having the same on the surface. Wood fiber board generally has the disadvantage that chipping and delamination are likely to occur when external force such as impact force is applied. When manufacturing a wood decorative board, it is partially applied to the wood fiber board by the impact force received in the manufacturing process. In some cases, chipping or delamination occurred. These are discarded as defective products and contribute to an increase in cost. Therefore, in Patent Document 1, a polymer compound other than a formalin resin is applied and impregnated on the surface of a wood fiber board, an aqueous adhesive is applied on the polymer compound in an uncured state, and a surface decorative material is laminated. It has been reported that a wood decorative board is produced by heat-pressing. According to the method for manufacturing a wood decorative board described in Patent Document 1, a high-hardness resin-impregnated layer made of a polymer compound is formed on the surface layer portion of the wood fiber board. Thereby, the impact resistance strength and peel strength of the wood fiber board are improved, and chipping and delamination generated in the wood fiber board due to the impact force received in the manufacturing process can be reduced.

Japanese Patent No. 3462656

  However, the following problems have been pointed out in the method for producing a wooden decorative board. That is, at the time of heat pressing, water or the like contained in the water-based adhesive becomes heated water, and this heated water penetrates into the portion on the opposite side from the side where the surface decorative material is laminated in the wood fiber board and acts greatly. Depending on the degree of action of the heated water, the wet heat load and the accompanying shrinkage received by the portion of the wood fiber board on which the surface decorative material is laminated are larger than those of the opposite portion, and warping occurs in the wood decorative board. If the amount of warping is large, it is discarded as a defective product.

  The present invention has been made in view of the circumstances as described above, and provides a method for manufacturing a wooden decorative board in which warpage generated when a wood fiber board and a surface decorative material are heat-pressed with an aqueous adhesive is reduced. It is an issue.

  The present invention relates to a method for producing a wooden decorative board in which a surface decorative material is laminated and integrated on the surface of a wooden fiber board or a composite material having the same, and an isocyanate compound is added to the surface of the wooden fiber board containing a water repellent. It is characterized by applying and impregnating and curing it, and then applying a water-based adhesive to the surface of the wood fiber board and heat-pressing the surface decorative material.

  In this wood decorative board manufacturing method, it is preferable that the water repellent has a melting temperature higher than the temperature at the time of thermocompression bonding of the surface decorative material.

  ADVANTAGE OF THE INVENTION According to this invention, the wooden decorative board which reduced the curvature produced when a wood fiber board and a surface decorative material are heat-pressed with a water-based adhesive can be obtained.

It is sectional drawing of the wooden decorative board manufactured by the manufacturing method of the wooden decorative board which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a wooden decorative board manufactured by the method for manufacturing a wooden decorative board according to the present embodiment.

  The wood decorative board 1 of FIG. 1 is provided with the composite material 4 which has the wood fiber board 2 on the surface, and the surface decorative material 5 laminated and integrated on the surface. The composite material 4 includes a wood fiber board 2 and a substrate 3.

  The wood fiber board 2 is, for example, a medium density fiber board (MDF) or a high density fiber board (HDF). In addition, a product obtained by pressing an insulation board, a kenaf fiber, a jute fiber, a synthetic fiber, etc., which are defibrated and mixed, and the like can also be used. Specific gravity and thickness are not particularly limited.

  The wood fiber board 2 contains a water repellent such as paraffin wax and fatty acid amide in order to suppress the ingress of moisture.

  Specific examples of the paraffin wax include petroleum-extracted and synthetic linear hydrocarbon paraffin waxes, branched hydrocarbon paraffin waxes, air-oxidized linear hydrocarbon paraffin waxes, and branched hydrocarbon oxide paraffins. Examples thereof include wax, low molecular weight polyethylene and low molecular weight polypropylene having a molecular weight of about 400 to 4000, and oxidized polyethylene and oxidized polypropylene obtained by air oxidation of these, and a maleic anhydride partial adduct of low molecular weight polyethylene and low molecular weight polypropylene. Specific examples of fatty acid amides include N, N′-ethylenebislauric acid amide, N, N′-methylenebislauric acid amide, N, N′-ethylenebisstearic acid amide, N, N′-ethylenebisoleic acid Examples include amides. These water repellents can be used alone or in combination.

  As the water repellent, those having a melting temperature higher than the temperature at the time of thermocompression bonding between the wood fiber board 2 and the surface decorative material 5 described later are preferably used. By impregnating the wood fiber board 2 with the water repellent having such a melting temperature, the elution of the water repellent at the time of thermocompression bonding by the heating water derived from the water contained in the aqueous adhesive is reduced, and the wood fiber board 2 Dimensional shrinkage can be suppressed, and warpage can be further reduced. When a water repellent having a melting temperature higher than the temperature at the time of thermocompression bonding between the wood fiber board 2 and the surface decorative material 5 is used, the water repellent having a melting temperature equal to or lower than the temperature at the time of thermocompression bonding Can also be used in combination.

  The water repellent is contained in the wood fiber board 2 to such an extent that it prevents moisture from entering the wood fiber board 2 and does not impair the strength, and preferably 1 wt% or more with respect to the wood fiber board 2. . More preferably, it is 1.2 wt% or more. The upper limit is not particularly limited, but can be set to, for example, 5 wt% in consideration of a decrease in strength of the wood fiber board 2 and the like.

  Such a water-repellent agent is produced by spraying and mixing the fibers in the process when the wood fiber board 2 is produced, or after forming into a plate shape, for example, by applying, spreading, dipping, etc. The plate 2 can be impregnated.

  In this embodiment, an isocyanate compound is applied to the surface of the wood fiber board 2 containing a water repellent, impregnated, and cured.

  An isocyanate compound is a compound having an isocyanate group in the molecule. Specific examples include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, xylylene diisocyanate tetramethylxylylene diisocyanate, hexamethylene diisocyanate, polyethylene diisocyanate, and the like. These can be used alone or in combination. You may mix a crosslinking accelerator etc. as needed.

  The isocyanate compound generally has good penetrability into the wood fiber board 2, but in order to improve the penetrability, for example, a low molecular weight having a weight average molecular weight of about 200 to 500 is preferably used. Moreover, the mixture with a dilution component can also be used not only a solvent and a non-solvent. If the permeability of the isocyanate compound is good, the curing (crosslinking) variation with the wood fiber board 2 is also reduced. Moreover, since it does not remain on the surface of the wood fiber board 2, it is possible to apply the aqueous adhesive without repelling the aqueous adhesive described later, and there is an advantage that the stability of the adhesive strength of the surface decorative material 5 is improved.

  The application of the isocyanate compound to the wood fiber board 2 can be performed using a general coating apparatus such as a roll coater or a flow coater. The applied isocyanate compound penetrates into the wood fiber board 2. Before applying the isocyanate compound to the wood fiber board 2, it is preferable to warm at least one of the wood fiber board 2 and the isocyanate compound in advance. By doing in this way, the viscosity of an isocyanate compound falls, fluidity | liquidity improves, and it can be made to impregnate in the wood fiber board 2 more effectively. The wood fiber board 2 can be evacuated during or after application to the wood fiber board 2 of the isocyanate compound. By vacuuming from the back side of the wood fiber board 2, the isocyanate compound can be forced into the wood fiber board 2 so that the wood fiber board 2 can be impregnated in a shorter time and surely. it can.

The amount of the isocyanate compound applied is appropriately set depending on the thickness of the wood fiber board 2, the temperature at the time of thermocompression bonding between the wood fiber board 2 and the surface decorative material 5, and the like. For example, when the surface decorative material 5 is heat-pressed to the wood fiber board 2 having a thickness of 2 to 3 mm using an aqueous adhesive at 100 ° C. ± 5 ° C. for about 1 minute, the solid content of the isocyanate compound is 20 to 150 g / m ^2. It is preferable to apply in the range. By applying the isocyanate compound within the range, the wood fiber board 2 penetrates well slightly from the surface layer portion to the inner portion, and the warp suppressing effect is further enhanced.

  As a method for curing (crosslinking) the isocyanate compound impregnated in the wood fiber board 2, it may be left in a room temperature environment to be cured by moisture, or may be heated to promote crosslinking.

  When the isocyanate compound is cured, a cured layer 6 of the isocyanate compound in which the isocyanate compound and the fibers of the wood fiber board 2 are firmly bonded is formed in the wood fiber board 2. In FIG. 1, the hardened layer 6 is formed on the surface side portion of the wood fiber board 2, but the hardened layer 6 is entirely formed in the wood fiber board 2 from the front surface to the back surface depending on the degree of penetration of the isocyanate compound. Sometimes formed.

  Thus, when the hardened layer 6 of the isocyanate compound is formed at least on the surface side portion in the wood fiber board 2, when the wood fiber board 2 and the surface decorative material 5 are heat-pressed with a water-based adhesive, water-based adhesion is achieved. The permeation into the wood fiber board 2 of heated water such as water contained in the agent is reduced. Thereby, the wood fiber board 2 becomes difficult to receive a wet heat load due to the action of heated water, and the dimensional stability is improved, for example, the dimensional shrinkage is suppressed. Further, elution of the water repellent impregnated in the wood fiber board 2 is suppressed by the presence of the hardened layer 6, and the water fiber repellent effect of this water repellent also heats the water such as water contained in the aqueous adhesive. 2 penetration is reduced. Thus, due to the synergistic effect of the curing of the isocyanate compound and the effect of suppressing the elution of the water repellent, the heating water such as water contained in the aqueous adhesive does not easily penetrate into the wood fiber board 2, and the heating water As a result, the heat and humidity load due to the action of the material is reduced, the dimensional stability is improved, and the amount of warpage is reduced.

  In the present embodiment, a water-based adhesive is applied to the surface of the wood fiber board 2, and the surface decorative material 5 is placed thereon and heat-pressed. Thereby, as shown in FIG. 1, the surface decorative material 5 is laminated and integrated on the surface of the wood fiber board 2 via the adhesive layer 7 of the water-based adhesive.

  The surface decorative material 5 is, for example, a veneer, a single plate, a printed sheet, or the like, and a surface whose surface is coated can also be used. When the wet veneer impregnated with moisture is used as the surface decorative material 5, the wet heat load received by the portion on the surface side of the wood fiber board 2 at the time of heat press-bonding to the wood fiber board 2 by the conventional method becomes particularly large. Although the amount of warpage increases, according to the present method, the amount of warpage of the wooden decorative board 1 can be reduced.

  The water-based adhesive is, for example, an emulsion-based adhesive, a water-soluble adhesive, a water-dispersed adhesive, or the like, and one containing a resin such as a vinyl acetate resin, an aqueous vinyl urethane resin, a melamine resin, or a urea resin is used. .

  In FIG. 1, a substrate 3 made of plywood, OSB (Oriented Strand Board), an inorganic board or the like is bonded to the back side of the wood fiber board 2 with the above-mentioned aqueous adhesive or the like. In the present embodiment, after the substrate 3 and the wood fiber board 2 are bonded and combined, the wood fiber board 2 is coated with an isocyanate compound, impregnated and cured, and then a water-based adhesive is applied to the surface decorative material. 5 is placed and thermocompression bonded. The bonding process between the substrate 3 and the wood fiber board 2 may not be before application to the wood fiber board 2 of the isocyanate compound. For example, it may be performed after the impregnation and curing of the isocyanate compound and before the application of the water-based adhesive, or after the thermocompression bonding of the surface decorative material 5.

  The wooden decorative board 1 obtained as described above has a small degree of warping, and is preferably used for interior building materials such as flooring materials and storage fitting materials.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the wood decorative board 1 in FIG. 1 employs a composite material 4 of a wood fiber board 2 and a substrate 3 as a base material to which the surface decorative material 5 is bonded, but the base material has a wood fiber board on the surface. As long as it is a composite material, the base material may be composed of only a wood fiber board.

<Example 1>
A board in which a wood fiber board containing a low melting point type water repellent and a substrate were bonded and combined with an aqueous vinyl urethane resin was prepared, and an isocyanate compound was applied to the surface of the wood fiber board with a roll coater and impregnated. Next, after allowing the isocyanate compound to harden for 4 days at 25 ° C., a vinyl acetate resin-based aqueous adhesive was applied to the surface of the wood fiber board, and a surface decorative material was further placed thereon at 110 ° C., 1 MPa, A wooden decorative board was obtained by heat-pressing under the condition of holding for 1 minute. In addition, the wood fiber board containing a water repellent is obtained by spraying and mixing a water repellent on a fiber at the time of producing the wood fiber board.

  The water repellent, wood fiber board, substrate, isocyanate compound and surface decorative material used are as follows.

・ Water repellent (low melting point type)
Polyethylene oxide WAX, melting point 65 ° C., 1.2 wt% added to wood fiberboard • Wood fiberboard MDF 2.7 mm thickness, specific gravity 0.7
-Substrate Eucalyptus plywood, 9.5 mm thickness-Mixture of isocyanate compound methylenebisdiisocyanate (MDI: diphenylmethane diisocyanate) and polyethylene diisocyanate, weight average molecular weight: about 400, coating amount (solid content): 60 g / m ²
-Surface decorative material wet veneer, 0.2 mm thick, tree species: beech, moisture content: about 90%
<Example 2>
A wood decorative board was obtained in the same manner as in Example 1 except that the wood fiber board containing the following high melting point type water repellent together with the low melting point type water repellent was used.

・ Water repellent (high melting point type)
Paraffin WAX, melting point 115 ° C., 1.2 wt% added to wood fiber board (low melting point type water repellent and high melting point type water repellent added 2.4 wt% in total to wood fiber board) Yes)
<Comparative Example 1>
A wooden decorative board was obtained in the same manner as in Example 1 except that the isocyanate compound was not used in Example 1.
<Comparative example 2>
A wooden decorative board was obtained in the same manner as in Example 2 except that the isocyanate compound was not used in Example 2.
<Comparative Example 3>
After applying the isocyanate compound in Example 1, instead of leaving it at 25 ° C. for 4 days to cure the isocyanate compound, the surface cosmetic material was water-based before the isocyanate compound was cured (10 minutes after the isocyanate compound was applied). A wood decorative board was obtained in the same manner as in Example 1 except that it was heat-pressed with an adhesive.
<Comparative example 4>
After applying the isocyanate compound in Example 2, instead of leaving it at 25 ° C. for 4 days to cure the isocyanate compound, the surface cosmetic material was water-based before the isocyanate compound was cured (10 minutes after applying the isocyanate compound). A wood decorative board was obtained in the same manner as in Example 2 except that it was heat-pressed with an adhesive.
<Comparative Example 5>
A wood decorative board was obtained in the same manner as in Example 1 except that the following phenol resin was used instead of the isocyanate compound in Example 1.

-Phenolic resin Weight average molecular weight: about 400, coating amount (solid content): 60 g / m ²
The amount of warp generated in the wood decorative board obtained as described above was measured to determine whether it was acceptable or not. The results are shown in Table 1. In addition, the measuring method of the curvature amount which generate | occur | produced in the wood fiber board, and the criterion of acceptance / rejection are as follows.
<Measurement method of warpage amount and acceptance criteria>
The size of the wooden decorative board was 30 cm wide × 180 cm long, and the amount of warpage in the width direction before and after thermocompression bonding of the surface decorative material was measured. The convex warpage is +, the concave warpage is-, and the warp amount is inconspicuous in the range of -0.5 mm to +0.5 mm. It was set as “x”.

  From the results in Table 1, it was confirmed that the wooden decorative boards obtained in Examples 1 and 2 had a reduced amount of warpage. In particular, the wood decorative board obtained in Example 2 impregnates the wood fiber board with a water repellent having a melting temperature higher than the temperature at the time of thermocompression bonding of the surface decorative material. ing. The wood decorative boards obtained in Comparative Examples 1 to 5 did not use an isocyanate compound, or even if an isocyanate compound was used, the surface decorative material was heat-bonded in an uncured state, so the amount of warpage was large. Yes.

1 Wood decorative board 2 Wood fiber board 4 Composite material 5 Surface decorative material

Claims (2)

  In a method for manufacturing a wooden decorative board in which a surface decorative material is laminated and integrated on the surface of a wooden fiber board or a composite material having the same, an isocyanate compound is applied and impregnated on the surface of the wooden fiber board containing a water repellent. A method for producing a wooden decorative board, comprising: curing the surface, applying a water-based adhesive to the surface of the wooden fiber board, and heat-pressing the surface decorative material.   The method for producing a wooden decorative board according to claim 1, wherein the water repellent has a melting temperature higher than a temperature at the time of thermocompression bonding of the surface decorative material.

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