JP5681909B2 - Wooden decorative board and method for producing the same - Google Patents

Description

  The present invention relates to a wooden decorative board used for interior building materials such as a flooring material for a house and a storage fitting material, and a method for manufacturing the same.

  A wood substrate used for interior building materials or the like is obtained by bonding and compounding a wood fiber board to the substrate surface from the viewpoint of improving surface smoothness.

  In general, a plywood, a particle board, an OSB (Oriented Strand Board) or the like is used as a substrate, and an MDF (Medium Density Fiberboard) or the like is used as a wood fiber board bonded and composited on the surface thereof.

  And a veneer board and a printing sheet are adhered to the surface of the wood fiber board as a surface decoration material using a water-based adhesive, and a wood decoration board is manufactured.

  In the production of this wooden decorative board, when adhering the surface decorative material with a water-based adhesive, it is bonded by heating and pressurizing, but the wooden fiberboard contracts in the surface direction due to the moist heat at the time of the heating and pressing process, There is a problem that warp occurs in the wooden decorative board.

  Therefore, in order to eliminate the warp, a process of forcibly flattening is performed using a warp straightener. However, forcible processing using a warp straightener has a problem that it is a batch type and the process steps increase.

  Also proposed is a method of laminating a plurality of wet veneers, dry veneers, and medium density fiberboards (MDFs), preliminarily imparting convex warpage, and resulting in a substantially flat result by heat and pressure treatment. (For example, refer to Patent Document 1).

JP-A-9-85715

  However, even with such a proposal, there are problems such as difficulty in stable production of the product because the condition of the convex warpage to be given in advance differs depending on the size and thickness of the target product and the production environment. .

  The present invention has been made in view of the circumstances as described above, and in order to bond a surface decorative material with a water-based adhesive, it is difficult to generate warp during the heating and pressurizing treatment, and its manufacture. It is an object to provide a method.

The present invention is characterized by the following in order to solve the above problems.
That is, the wooden decorative board of the present invention is a wooden decorative board in which a wooden fiber board is bonded onto a substrate, and a surface decorative material is integrated on the surface of the wooden fiber board via an aqueous adhesive. The fiberboard is one that has been humidified and heated under reduced pressure , and the wood fiberboard contains a water repellent, and the surface temperature of the wood fiberboard during the humidification heat treatment is the melting temperature of the water repellent. It is characterized by being less than .

Also, the method for producing a wood decorative board according to the present invention is such that a wood fiber board is bonded onto a substrate, and the surface decorative material is heated and pressed through an aqueous adhesive on the surface of the wood fiber board. A method of manufacturing a wood decorative board , wherein the wood fiber board is subjected to humidification heat treatment in a reduced pressure state , and the wood fiber board contains a water repellent, and the wood fiber during the humidification heat treatment The surface temperature of the plate is less than the melting temperature of the water repellent .

  According to the wood decorative board of the present invention and the manufacturing method thereof, the substrate and the wood fiber board that has been previously humidified and heated in a reduced pressure state are bonded together, and then the surface decorative material is heated and pressurized through an aqueous adhesive. Since it is a wooden decorative board, the shrinkage of the wooden fiber board can be kept low, and a wooden decorative board with suppressed warpage can be obtained.

It is a schematic sectional drawing for demonstrating the manufacturing process of the wooden decorative board of this invention.

  The wood decorative board of the present invention is obtained by adhering a wood fiber board on a substrate to form a composite board, and subjecting the surface of the composite board to a wood fiber board by heat-pressing the surface decorative material via an aqueous adhesive. In order to prevent warping during heating and pressurizing treatment, the wood fiberboard is previously preliminarily humidified and heat-treated in a reduced pressure state.

First, the configuration for preventing the occurrence of warpage of the present invention will be described in detail.
Usually, a wood fiber board bonded and composited to the substrate surface is coated in the surface direction by applying a water-based adhesive to adhere the wood fiber board and the surface decorative material, and then applying heat and pressure during the heat and pressure treatment. Shrink.

  On the other hand, an appropriate water repellent may be added to the wood fiber board in order to obtain water resistance. In many cases, a plurality of water repellents are used in combination. When heat resistance and water resistance are taken into account, for example, the water repellent has a melting point of about 70 ° C., a paraffin wax, or a melting point of A synthetic resin wax of 100 ° C. or higher, for example, a polyethylene composite wax is used.

  The degree of shrinkage of the wood fiberboard due to the heat and pressure treatment varies depending on the type of water repellent added to the wood fiberboard, the amount of water repellent added, the type of aqueous adhesive, the amount of aqueous adhesive applied, etc. Therefore, it is very difficult to completely suppress the shrinkage of the wood fiber board.

  Therefore, in the present invention, the wood fiber board alone is preliminarily humidified and heat-treated to moderately swell, thereby reducing the compression strain during the production of the wood fiber board. Since this relaxation is maintained even after the humidified heat treatment, the supplied moisture is removed, the wood fiber board and the surface decorative material are heated and pressurized through the aqueous adhesive. It is a wooden decorative board which suppresses shrinkage and hardly warps.

  The humidification heat treatment conditions to be applied to the wood fiber board in advance can be set as appropriate depending on the type, thickness, etc. of the wood fiber board, but regarding the heating conditions, the wood fiber board contains a water repellent. In this case, it is more preferable that the surface temperature of the wood fiber board is lower than the melting temperature of the water repellent agent added to the wood fiber board.

  By making the surface temperature of the wood fiber board less than the melting temperature of the water repellent added to the wood fiber board, it becomes possible to suppress the melting and outflow of the water repellent from the wood fiber board. The dimensional stability of the wood fiber board can be made more excellent.

  Here, the surface temperature of the wood fiber board in the present invention means a heating temperature (atmospheric temperature at the time of heating) under the conditions of the humidification heat treatment.

  In addition, when several types of water repellent is contained in the wood fiber board, it can be set as the heating conditions below the highest melting temperature of the water repellent.

  That is, when a plurality of types of water repellent are included in the wood fiber board, it is sufficient that at least one type of water repellent is included in the wood fiber board when the humidification heat treatment is completed.

  Moreover, the humidification heat processing performed to a wood fiber board by this invention performs humidification heat processing in a pressure-reduced state.

  By performing the humidification heat treatment in a reduced pressure state, moisture can be uniformly permeated into the interior of the wood fiberboard at the end of the humidification heat treatment, that is, when the pressure is returned to normal pressure. It becomes possible to relieve the compression strain more uniformly.

  There are no particular restrictions on the method of humidifying and heat-treating in a reduced pressure state, but for example, a method of supplying steam under a reduced pressure environment using a pressure reducing kettle, or a method in which high temperature steam is introduced into a sealed pressure reducing kettle and then the temperature is lowered. Various methods such as a method of reducing the pressure in a steam environment, and a method of generating a steam in a decompression kettle to obtain a saturated steam environment can be employed.

  In addition, the method of placing the wood fiberboard in the decompression kettle may be stacked or vertically installed as long as the steam comes into contact with the wood fiberboard. In order to prevent deformation, a load can be applied at a pressure smaller than the pressure at which the wood fiber board is molded.

  In the case of laminating wood fiberboards, it is possible to adjust the number of stacking stages as necessary, or to interpose a spacer between the wood fiberboards so as to facilitate contact with steam.

  In consideration of such matters comprehensively, the conditions of the humidification heat treatment preliminarily applied to the wood fiberboard include a saturated water vapor pressure at a temperature of 40 to 120 ° C. (eg, about 0.01 MPa at 50 ° C., 120 ° C. About 0.2 MPa) can be a preferable range.

  Under such conditions, the wood fiberboard is preliminarily humidified and heat-treated, so that even when the composite board and the surface decorative material are integrated by heat and pressure treatment through an aqueous adhesive, The contraction of the wood fiber board which comprises can be suppressed low, and the curvature of a wood decorative board can be suppressed.

Next, each material which comprises the woody decorative board of this invention is explained in full detail.
<Board>
The substrate used in the present invention can be used without particular limitation as long as it is a substrate usually used for a wood decorative board, and examples thereof include plywood, particle board, OSB (Oriented Strand Board), LVL ( Wood based substrates such as Laminated Veneer Lumber) and inorganic substrates.

  Among these, plywood is preferable, and plywood such as lauan, eucalyptus, falkata, chameleon, drill, rubberwood, poplar, cedar, larch, hinoki can be suitably used.

<Wood fiber board>
The wood fiberboard used in the present invention can be used without particular limitation as long as it is a generally known wood fiberboard, and examples thereof include MDF, HDF (Hight Density Fiber Board), insulation board, Examples thereof include kenaf fibers, jute fibers, and synthetic fibers that have been defibrated and pressed. And in this invention, what performed the humidification heat processing to these wood fiber boards in the pressure reduction state previously is used.

<Composite board>
The substrate and the wood fiber board are bonded via an adhesive to form a composite board. The adhesive used here can be used without particular limitation as long as it is an adhesive generally used for bonding a substrate and a wood fiber board, and various types including those conventionally known can be used. It is. A material widely used for general woodworking such as a vinyl acetate resin adhesive, a PUR (Poly Urethane Reactive) adhesive, or the like can be suitably used.

  PUR is a reactive hot-melt resin, which is made of polyurethane-based uncured resin (prepolymer) as a main component, heat-dissolved, and then reacts with water, for example, moisture in a wood fiberboard, and is particularly suitable. Can be used.

<Surface decorative material>
The surface decorative material used in the present invention can be appropriately selected depending on the intended use of the wooden decorative board of the present invention.

  Examples of these include, for example, synthetic resin sheets (films) with various patterns, thin sheet-like veneers formed by thinly slicing natural name wood, among these, aesthetics, A veneer can be preferably used from the viewpoint of material feeling and the like.

  Specifically, wood veneers such as beech, oak, oak, walnut, walnut, beach and birch can be suitably used.

<Water-based adhesive>
The water-based adhesive for adhering the wood fiber board and the surface decorative material can be used without particular limitation as long as the wood fiber board and the surface decorative material can be firmly bonded to each other. Examples thereof include aqueous adhesives such as urethane resin adhesives, aqueous vinyl acetate resin adhesives, and aqueous isocyanate resin adhesives.

  Hereafter, the manufacturing method of the wooden decorative board of this invention is explained in full detail using figures. FIG. 1 is a schematic cross-sectional view for explaining the steps of the production method of the present invention.

  First, as shown in FIG. 1 (A), the wood decorative board of the present invention is obtained by using an adhesive 3 such as a PUR-based adhesive on a substrate 1 and a wood fiber board 2 that has been previously humidified and heated in a reduced pressure state. To form a composite plate 4 shown in FIG. The adhesive 3 can be applied to one or both surfaces of the substrate 1 and the wood fiber board 2, and the adhesive 3 application surface can be combined and bonded by heating and pressing to form the composite board 4.

  Next, as shown in FIG. 1 (C), a water-based adhesive 6 is applied to the surface of the wood fiber board 2 of the composite board 4, and the surface decorative material 5 is placed thereon, and heat and pressure treatment is performed from above and below. Then, they are laminated and integrated into a wooden decorative board 7 shown in FIG.

  The application method of the adhesive 3 and the water-based adhesive 6 at the time of manufacturing the woody decorative board 7 of the present invention is not particularly limited, and various application methods such as roll coater, spray coating, and hand coating can be employed. .

  In addition, the heat and pressure treatment conditions for the composite board 4 and the surface decorative material 5 are appropriately set according to the thickness of the substrate 1, the wood fiber board 2, the surface decorative material 5, the type of the water-based adhesive 6, and the like. For example, the conditions of 80 to 190 ° C. and 1 to 5 MPa are considered.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

(Example 1)
A 9.5 mm thick eucalyptus plywood substrate and a 2.7 mm thick conifer MDF (made by N & E Co.) as a wood fiberboard with a specific gravity of 0.8 are bonded together with a reactive hot melt adhesive: PUR. A composite plate was made.

  The wood fiberboard is a water repellent agent to which a paraffinic wax having a melting point of 70 ° C. and a polyethylene composite wax having a melting point of 100 ° C. are added in advance, and the surface temperature of the wood fiber board is 110 ° C. What was processed on the saturated water vapor pressure of atmospheric pressure 0.14MPa, and the pressure-humidification heat processing conditions hold | maintained for 2 minutes was used.

  An aqueous vinyl acetate resin adhesive is uniformly applied on the wood fiber board of this composite board by a roll coater, and a beech material having a thickness of 0.2 mm and a moisture content of about 90% is applied thereon as a surface decorative material. A wet veneer was piled up and heat-pressed to produce a wood decorative board.

The heat and pressure treatment conditions were 110 ° C., 1 MPa, and 1 minute.
(Example 2)

  Example 1 except that the wood fiberboard was processed under the conditions of reduced pressure humidification and heat treatment under the conditions of a surface temperature of the wood fiberboard of 85 ° C., a saturated water vapor pressure of 0.06 MPa, and a 3-minute holding condition. A wood veneer was prepared using the same materials and conditions as in Example 1.

(Comparative example)
A wooden decorative board was prepared using the same material and conditions as in Example 1 except that a wooden fiber board not subjected to reduced-pressure humidification heat treatment was used as the wooden fiber board.

  About the produced wood decorative board, the determination of curvature (warpage amount) and the determination of thickness direction dimensional stability (surface roughness Ra) were performed according to the following criteria.

(Criteria and evaluation of warpage)
The amount of warpage was measured by setting the size of the wood decorative board to 30 cm in width and 180 cm in length, and the amount of warpage in the width direction before and after sticking the veneer was set to + for convex warpage and-for concave warpage.

  The amount of warpage was evaluated from the measurement result of the amount of warpage. -0.5 mm to +0.5 mm where width warp is not conspicuous was marked with ◯, and those outside this range were marked with x. The results are shown in Table 1.

(Criteria and evaluation of thickness direction dimensional stability (surface roughness Ra))
The surface roughness of the wood fiber board was measured, and the dimensional stability in the thickness direction was evaluated. Evaluation is 5μm or less, which is equivalent to a wood fiber board that has not been treated with reduced-pressure steam, and has a high smoothness. Difficult 10 μm or less was marked with ◯, and when it exceeded 10 μm where the difference in unevenness was found by touching with the hand, x was evaluated (the result of evaluation was that there was no x exceeding 10 μm). The results are shown in Table 1.

<Evaluation results>
It was confirmed that Examples 1 and 2 using the wood fiber board which performed the pressure reduction humidification heat processing suppress a curvature compared with the comparative example which does not perform a pressure reduction humidification heat processing.

  From these results, it was confirmed that the reduced pressure humidification heat treatment for the wood fiber board of the present invention has an effect of suppressing the warp on the wood decorative board.

  Furthermore, as a result of sanding the surface of the wooden decorative board prepared in Examples 1 and 2 and performing the floor coating finish, it was not possible to confirm defects in appearance and plane peel strength.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Wood fiber board 3 Adhesive 4 Composite board 5 Surface cosmetics 6 Water-based adhesive 7 Wood decorative board

Claims (2)

A wooden decorative board in which a wooden fiberboard is bonded on a substrate, and a surface decorative material is integrated on the surface of the wooden fiberboard via a water-based adhesive, and the wooden fiberboard is humidified and heated under reduced pressure It is treated , and the wood fiber board contains a water repellent, and the surface temperature of the wood fiber board when the humidification heat treatment is performed is less than the melting temperature of the water repellent. Wooden decorative board. A method for producing a wooden decorative board, comprising: adhering a wooden fiber board on a substrate and integrating the surface decorative material by heating and pressing the surface of the wooden fiber board via a water-based adhesive. The fiberboard is one that has been humidified and heated under reduced pressure, and the wood fiberboard contains a water repellent, and the surface temperature of the wood fiberboard during the humidification heat treatment is the melting temperature of the water repellent. A method for producing a wooden decorative board, characterized by comprising less than