JP4996544B2 - Method for producing decorative base material - Google Patents

Description

  The present invention relates to a method for producing a decorative base material having excellent caster resistance.

Conventionally, as shown in, for example, Patent Document 1, as a method of manufacturing a flooring material in which a surface finishing material is attached to one side of a wooden board via an adhesive, a rubber adhesive and a resin are provided on one side of the wooden board. A method is known in which a mixed adhesive mixed with a system adhesive is subbed and dried, and then a surface finishing material is placed on the upper surface and adhered. When manufactured by this method, since a rubber-based adhesive (soft having rubber elasticity after curing) is used, rubber elasticity is exhibited after curing. Therefore, it is effective to prevent the thin wood veneer surface from being peeled off due to repeated load generated when the chair or furniture with casters is moved. Thus, the performance of the flooring which is not destroyed even by repeated loading due to long-term use of casters is called “caster resistance”.
JP 2003-211420 A

  However, in that case, when a wood thin veneer with a moisture content higher than the air dry moisture content (about 5 to 7%) is attached as a surface finish by a hot press, the hot press is depressurized. At the same time, the moisture of the wood thin veneer evaporates, and there is a problem that the veneer crack occurs due to the contraction of the wood thin veneer itself. This phenomenon is likely to occur when a soft adhesive layer having a constant thickness and rubber elasticity is formed. This is because the soft adhesive layer having rubber elasticity is weak in suppressing the shrinkage of the thin wood veneer. In addition, as a woody thin veneer, it particularly appears when a woody thin veneer with a grain pattern is used. This is because anisotropic shrinkage occurs when a woody thin veneer with a grain pattern is used.

In order to solve this problem, for example, as in Patent Document 2, there is a method of providing a single paper layer between a base material and a thin wood veneer. However, according to this method, an adhesive is applied to load paper. Further, after providing an adhesive layer with a press, a plurality of steps of applying an adhesive and laminating a thin wood single plate are required, which has been a factor in reducing manufacturing efficiency.
JP-A-9-141610

  The present invention has been made in view of such points, and its purpose is to efficiently produce a base material that is excellent in caster resistance and has excellent castor resistance and cosmetic properties that are less likely to cause a single plate cracking phenomenon. It is to provide a manufacturing method that can be used.

  In order to achieve the above object, in the invention of claim 1, by applying a soft adhesive having a hardness after curing of 30 ° or less with a type A durometer to the surface of the wooden base material and semi-curing it. An adhesive layer forming step for forming a semi-cured adhesive layer, a laminating step for laminating a thin wood veneer with a moisture content of 4% or less on the semi-cured adhesive layer, and the laminate And a hot press process for obtaining a decorative base material having an adhesive layer having a predetermined thickness by curing the adhesive layer and hot-pressing the laminate. In this case, the moisture content is based on the absolute dry veneer weight, and so on.

  In this case, according to the said manufacturing method, the decorative base material without a single board crack can be manufactured even after a hot-pressing process. In addition, it has an adhesive layer of a predetermined thickness with a soft adhesive that has a hardness after hardening of 30 degrees or less with a Type A durometer, just below the thin wood plate to be bonded and integrated. It becomes a cosmetic base material with excellent castor resistance.

  As described above, according to the method for producing a decorative base material of the present invention, when the heat pressure is integrated by a hot press, a wood thin veneer having a moisture content of 4% or less is used to No decorative base material can be produced. In addition, by applying an adhesive to the surface of the wooden substrate and semi-curing it, the adhesive layer can be stably formed with a predetermined thickness, so that it is possible to produce a decorative substrate with excellent castor resistance. it can.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. However, the following description of the embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use at all.

  FIG. 1 is a diagram showing an example of a method for producing a decorative base material of the present invention.

(A) Adhesion layer formation process First, the adhesive layer 2 of a semi-hardened state is formed by apply | coating an adhesive agent on the wooden base material 1, and semi-hardening the adhesive agent. As a means for applying the adhesive, a flow coater or a roll coater is preferably used, and the adhesive is applied so that the adhesive layer 2 having a thickness of 30 to 75 μm is formed.

  As a means for semi-curing the adhesive, for example, when an adhesive obtained by mixing a small amount of an isocyanate resin with a vinyl acetate resin is used, a heating means such as infrared rays or a ventilation dryer is used. For example, when an ultraviolet curable acrylic adhesive is used, an ultraviolet reaction initiator is used in combination, and a semi-cured state is obtained by ultraviolet irradiation.

  The semi-cured state here is a state in which curing has progressed to the extent that no liquid adhesive exists, for example, a liquid adhesive in which only the surface of the adhesive is film-cured and not cured inside Does not include the state that exists. It means a state in which the entire gelation of the adhesive has been completed and the surface thin wood veneer can be bonded by a subsequent hot press process. For example, in the case of semi-curing by heating, the curing state is appropriately adjusted depending on the heating temperature and heating time. For example, in the case of semi-curing by ultraviolet irradiation, the amount is appropriately adjusted depending on the ultraviolet irradiation amount and the ultraviolet irradiation time. If the curing is insufficient, an uncured liquid resin protrudes in the hot-pressing process, so that an appropriate thickness of the adhesive layer 2 cannot be ensured. Accordingly, the decorative base material 10 is inferior in caster resistance. On the other hand, if the curing progresses too much, the adhesion between the adhesive layer 2 and the thin wood veneer 4 will deteriorate, causing various problems such as peeling of the veneer by the caster resistance test and cracking by the heat resistant drying test. To do.

  The wood substrate 1 may be wood, for example, a wood fiber board such as an insulation board, MDF, or hard board, or a wood board such as plywood or particle board. In any case, in order to use as a flooring, it is desirable that the wooden substrate 1 has at least a hard surface. As a method for reinforcing the surface of the wood substrate 1, the surface layer may be impregnated with melamine resin, phenol resin, epoxy resin, urethane resin or isocyanate resin, melamine resin impregnated paper, phenol resin impregnated paper, etc. A reinforcing layer made of various types of resin-impregnated paper may be provided on the surface layer. Also, instead of resin-impregnated paper, hard artificial resin wood mainly made of wood powder, wood fiber, wood slices, etc., and kneaded and molded with various resins, or hard wood fiber boards such as MDF, hardboard, etc. The wood substrate 1 or the like may be stuck on the surface to strengthen the surface. In this case, the wood fiber board such as MDF or hardboard may be reinforced with resin impregnation. Most preferably, a woody plate-like body in which a hard woody base material 1 such as MDF or hardboard is attached to the surface of a plywood or the like is used.

  The adhesive layer 2 is made of a hardened product of a soft adhesive whose hardness after curing is 30 ° or less with a type A durometer. In particular, when the decorative base material 10 is used as a flooring material, the adhesive layer 2 has a predetermined thickness and elasticity, so that the wood thin veneer can be peeled even for a long-term continuous load of casters. Can be suppressed. The predetermined thickness of the adhesive layer 2 is 30 μm to 75 μm. This is because if the thickness is less than 30 μm, the buffering effect against the use of casters is weakened, and if the thickness is more than 75 μm, the sinking by the casters becomes too large, and single plate breakage occurs.

  Examples of the adhesive forming the adhesive layer 2 include thermoplastic resins such as vinyl acetate resins, latex resins and rubber resins, and modified products thereof, acrylic resins, urea melamine resins, and epoxy. A mixture of a thermosetting resin such as a phenolic resin, a phenolic resin or an isocyanate resin, or a modified product thereof is preferably used. Most preferably, an adhesive obtained by mixing a small amount of a curing agent such as an isocyanate resin or an epoxy resin with a thermoplastic resin such as a vinyl acetate resin or a latex resin is used.

  As the adhesive, any resin having rubber elasticity can be used. If rubber elasticity can be realized by a single resin, for example, a vinyl acetate adhesive or an acrylic adhesive is used alone. May be used.

  Furthermore, in order to increase the application amount of the adhesive and form the adhesive layer 2 with an appropriate thickness, it is preferable to add various thickeners and extenders to increase the viscosity. As the thickener, for example, flour or poval is used. As the extender, calcium carbonate, alumina, titanium oxide or the like is used.

  Moreover, in order to improve the concealment property of the wooden substrate 1, various pigments may be added and colored.

(B) Lamination process Next, the thin wood board 4 is laminated | stacked on the adhesive layer 2 of a semi-hardened state, and the laminated body 6 is obtained. The placed wood thin veneer 4 may be temporarily fixed. As a method for temporary fixing, a method in which moisture in the temporarily fixed portion is blown off by high frequency or the like and the adhesive is solidified is preferably used.

  At this time, a thin slice obtained by slicing a natural wood material or a laminate of natural wood materials can be used as the wood thin veneer 4. Any natural wood material can be used, such as conifers, hardwoods, and fast-growing trees. What sliced the laminated body of natural wooden material is what is called an artificial veneer.

  Further, as the wood thin veneer 4, a dry veneer having a moisture content of 4% or less can be used. In this case, if the thickness of the wood thin veneer 4 is too thick, not only will it take time to dry, but also the decorative base material 10 will be inferior in the resistance to dry cracking of the surface. The thickness is preferably about 15 to 1.0 mm, and most preferably about 0.25 to 0.6 mm.

(C) Hot-Pressing Step Further, the laminated body 6 is hot-pressed and laminated and integrated to obtain a decorative base material 10. There are various hot pressing methods such as a general roll press and a flat plate press, and a flat plate press is preferably used. The hot press is performed at a temperature of 100 to 130 ° C. and 0.2 to 1.0 MPa for about 30 to 90 seconds. As a result, the adhesive is completely cured, and the adhesive layer 2 has a thickness of 30 μm to 75 μm and a hardness of 30 ° or less with a type A durometer.

  Most preferably, a flat plate press is used, and the thin wood veneer 4 is laminated on the semi-cured adhesive layer 2 and heated for 30 to 90 seconds under a hot press condition of about 120 ° C. and 0.7 to 0.9 MPa. , Hot press.

  As described above, the adhesive layer 2 is completely cured by the hot-pressing process, and the wood base material 1 and the wood thin veneer 4 are laminated and integrated through the adhesive layer 2 having a constant thickness and rubber elasticity. The decorative substrate 10 can be obtained.

  For example, the surface of the wood thin veneer 4 is subjected to a floating process, the wood thin veneer 4 is impregnated with a resin, or a transparent coating layer is provided on the surface. A decorative board is obtained by applying a decorative process.

(Effect of embodiment)
Thus, according to the manufacturing method which concerns on embodiment of this invention, the decorative base material 10 which is excellent in the design property which does not have a single-plate crack can be manufactured efficiently.

  Furthermore, since the adhesive layer 2 having a hardness of 30 ° or less with a type A durometer and having a predetermined thickness is interposed between the wood substrate 1 and the wood thin veneer 4, the wood substrate 1 is a hard fiberboard such as MDF or hardboard or a hard base material reinforced with a surface resin, and even if it is a plywood with irregularities and uneven suction on the surface, the thickness of the adhesive layer 2 is reduced. It can be secured sufficiently. As a result, even if a caster is used continuously for a long time, the stress is dispersed and the decorative base material 10 having excellent performance capable of effectively suppressing the peeling of the thin wood veneer 4 is manufactured. can do.

  Next, specific examples will be described.

(Example)
A substrate plywood having a thickness of 11.5 mm, in which a plurality of single plates were stacked so as to be orthogonal to each other and the surface single plates were arranged in the longitudinal direction, was cut into a rectangle of 310 × 1850 mm. A soft adhesive having the following composition was applied to the surface of the substrate plywood at 100 g / m 2.
<Soft adhesive>
-Modified vinyl acetate adhesive: 100 parts by weight-Epoxy crosslinking agent: 10 parts by weight

  Ventilation was performed at a temperature of 60 ° C. with a dryer, curing was performed for 10 minutes, and semi-cured to form an adhesive layer. On top of this, a wood grain thin veneer of rice bran having a thickness of 0.25 mm and adjusted to a moisture content of 3% is placed, and laminated and integrated by a hot press (120 ° C., 90 seconds, 1.2 MPa). A cosmetic base was produced.

  Observation of the surface of the decorative base material after the hot press process showed a good situation with no single plate cracking.

(Comparative example)
In the said Example, the makeup | decoration base material was obtained on the same conditions except having used the wood grain thin single board of the rice bran which was 0.25 mm in thickness and adjusted to the moisture content 12% as a thin wooden board.

  When the surface of this decorative substrate was observed after the hot-pressing step, single plate cracks (cracks) occurred in some places, and the adhesive layer was exposed from the cracks in the thin wood single plate.

  INDUSTRIAL APPLICATION This invention is very useful in the manufacturing method of a decorative board utilized as a flooring excellent in caster resistance, and its industrial applicability is high.

Process drawing which shows the manufacturing method of the decorative base material 10 which concerns on embodiment of this invention.

Explanation of symbols

(A) Adhesive layer forming step (b) Laminating step (c) Hot-pressing step 1 Wood substrate 2 Adhesive layer 4 Wood thin veneer 6 Laminate 10 Cosmetic substrate

Claims (1)

An adhesive layer forming step of forming a semi-cured adhesive layer by applying a semi-cured soft adhesive having a hardness after curing of 30 ° or less with a type A durometer on the surface of the wood substrate;
On the semi-cured adhesive layer, a lamination step of laminating a thin wood veneer with a moisture content of 4% or less to obtain a laminate,
Hot-pressing the laminate, hot-pressing the laminate and curing the adhesive layer to obtain a decorative substrate having an adhesive layer with a predetermined thickness; and
A method for producing a decorative base material, comprising:

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