JP5769111B2 - Veneered decorative board - Google Patents

Description

  The present invention is a surface material for building interior materials such as wall materials, ceiling surface materials and movable partitions, surface materials for furniture such as baskets, tables and chairs, general wood products such as furniture, and surface materials for electronic devices and musical instruments. More particularly, the present invention relates to a veneered veneer that can prevent discoloration and contamination of the veneer on the surface.

  A veneer decorative veneer generally uses a wood-based base material such as plywood or fiberboard. The veneer is attached to the surface of the veneer via an adhesive, and the veneer surface is transparent or colored. It is manufactured by applying. Further, if necessary, a fiber sheet or a concealing agent may be interposed in advance on the veneer side surface of the wooden base material.

  Prevention of discoloration of wood is one of the major issues in using wood. Discoloration is caused by various factors, including chemical factors such as iron contamination and alkali contamination, and physical factors such as light and temperature. In recent years, discoloration of products in which a veneer or white oak veneer veneer is pasted on a wood substrate such as medium density fiberboard (MDF) is increasing. In particular, cases have been reported in which discoloration of oak and white oak veneer finishes used for furniture, doors, wall surfaces, etc. has occurred after two to three years. This phenomenon is thought to result from tannins that are abundant in oak and white oak. Tannins are highly chemically reactive, causing iron contamination that combines with iron ions to become black brown, alkali contamination to brown, acid contamination that changes to reddish, oak and white oak wood are highly susceptible to discoloration It is said. It is reported that it is particularly likely to occur at high temperatures and high humidity, and there is a possibility that biological contamination is involved.

  Against this background, tannic acid reacts with iron by treating oak flitch or oak slice veneer with an aqueous solution of disodium ethylenediaminetetraacetate as a method for preventing contamination during the production of slice veneers. The technique which prevents this or decomposes tannic acid has been disclosed (see Patent Document 1).

  In addition, in the decorative board having a veneer bonded to the surface of the wood substrate, a coating solution containing an ethylenediaminetetraacetic acid (EDTA) or hydroxyethylidene bisphosphonic acid (HEDP) chelating agent on the veneer surface or the base material surface An applied decorative board is disclosed (see Patent Document 2).

Furthermore, as a countermeasure against iron contamination of a veneered veneer using a plaster material or the like, a technique of applying about 27 g / m ² of a 1% polyphosphoric acid aqueous solution to the veneer surface has been reported. (Refer nonpatent literature 1.).

  JP-A-6-31705   JP 2009-202462 A

  Tsutomu Matsuura “Prevention of iron contamination of wood”, Hiroshima Prefectural Tobu Industrial Technology Center research report, No. 16 (2003)

  However, although the above-described treatment method can obtain a certain degree of discoloration preventing effect, it cannot obtain a sufficient effect under a severe environment of high temperature and high humidity. In addition, applying a chelating agent to the surface of the veneer is problematic because it may change to a color different from the original color of natural wood after treatment or may change over time from the untreated veneer. is there. The present invention has been made in view of the above problems, and an object of the present invention is to provide a decorative board that does not cause discoloration contamination of a veneer even when it is placed for a long time under high temperature and high humidity conditions.

  In order to solve the above-mentioned problem, the first means of the present invention is a veneered veneer, in which a natural wood ultrathin veneer, a layer containing a chelating agent, a moisture-proof sheet, and a woody base material are arranged in this order. It is characterized by being laminated and integrated.

  The second means is the veneered decorative board described in the first means, wherein the chelating agent is ethylenediaminetetraacetic acid.

The third means is the veneered decorative board according to the second means, wherein a layer in which the chelating agent is mixed with the adhesive is formed, the coating amount of the layer is 30 to 90 g / m ² , and the chelating agent The ratio is 0.2 to 4.0% by weight.

The fourth means is a veneer decorative board according to the second means, wherein the chelating agent is applied in the form of an aqueous solution (the amount of the chelating agent applied is 0.4 to 4.0 g / m ² ), and then It is obtained by drying and is laminated through a veneer and an adhesive.

  The fifth means is a veneered decorative board according to any one of the first to fourth means, wherein the moisture-proof sheet has a structure in which a fiber sheet is laminated on both sides of an aluminum foil, or a fiber on both sides of a synthetic resin layer. It is characterized by a structure in which sheets are laminated.

Sixth means is the veneered decorative board according to any one of the first to fifth means, wherein the moisture permeability of the moisture-proof sheet (JIS Z 0208) is 25 g / m ² · 24 hours (40 ° C.) or less. It is characterized by.

  In the decorative board of the present invention, a moisture-proof sheet is arranged between the veneer on the surface and the wooden base material, so that the metal, synthetic resin component or wood component in the wooden base material enters the veneer with moisture. It is preventing. In addition, when a chelating agent is internally added to the adhesive between the surface veneer and the moisture-proof sheet, the surface layer part of the veneer and the chelating agent come into contact with each other, and metals, particularly iron ions and tannins, are in the veneer. And discoloration due to reaction with phenol components. Thus, the decorative board of the present invention produced by the combined use of the chelating agent-added adhesive and the moisture-proof sheet does not cause discoloration contamination of the veneer on the surface of the decorative board even if it is placed for a long time under high temperature and high humidity conditions, and is good. Effects can be obtained.

  In addition, when a chelating agent is applied to the moisture-proof sheet surface on the surface veneer side, an adhesive is further applied thereon, so that the chelating agent partially dissolves in the adhesive, resulting in a surface veneer A surface layer part and a chelating agent will almost contact. For this reason, discoloration is prevented and a good effect is obtained as in the case where a chelating agent is internally added.

  In the present invention, the veneer itself is not subjected to treatment such as direct application or impregnation of a chemical such as a chelating agent, and there is no risk of discoloration of the veneer due to the chemical, and is the same as a normal untreated veneer-coated decorative plate The appearance stability is maintained.

  It is a veneer sticking decorative board sectional view using a chelating agent addition adhesive.   FIG. 3 is a cross-sectional view of a veneered decorative board in which a chelating agent is applied to a moisture-proof sheet surface.   It is a photograph showing the veneer surface state of the decorative board 17 days after the evaluation test in Example 1.   It is a photograph showing the veneer surface state of the decorative board 30 days after the evaluation test in Example 2.   It is a photograph showing the veneer surface state of the decorative board 7 days after the evaluation test in Example 3.

  Hereinafter, embodiments of the present invention will be described in detail. The decorative board of the present invention has a veneer stuck to the outermost surface of a wooden base material, and is used for wall materials, ceiling materials, floor materials, etc. in interiors of houses, etc., and furniture and furniture Etc. are used similarly.

  Examples of the wood-based substrate include plywood, fiberboard, particle board, LVL, laminated wood, and the fiberboard includes insulation board, medium density fiberboard (MDF), and hard board.

  Usually, natural wood veneer called veneer is made by boiling or steaming wood called flitch if necessary, and using a veneer cutting machine such as slicer lace, rotary lace, half rotary lace, etc. It is made by cutting to a thickness of (0.08-30 mm). Wood types include white oak, red oak, chestnut, mahogany, teak, maple, American cherry, white ash, silver heart, hippo, walnut, bubinga, beech, oak, chestnut, tammo, cedar and cypress. However, the decorative board of the present invention can be expected to be particularly effective with a material type that easily undergoes discoloration contamination over time. As one of the causes of discoloration contamination, the tannin content and the pH are involved, and it is said that the tannin content and the pH are particularly likely to occur in a material type having a high tannin content. Examples of grades with a high tannin content include oak, white oak, red oak, chestnut, chestnut, and walnut.

  FIG. 1 is a cross-sectional view of a veneered decorative board using the chelating agent-added adhesive of the present invention. FIG. 2 is a cross-sectional view of a veneered decorative board in which the chelating agent of the present invention is applied to the moisture-proof sheet surface.

The moisture-proof sheet 5 disposed between the veneer 3 and the wooden base material 7 prevents the components in the wooden base material from entering the veneer side together with moisture, and the humidity of the outside air passes through the base material. Therefore, any sheet-like material satisfying this requirement may be used. This moisture-proof sheet has limited moisture resistance, and the moisture permeability is 50 g / m ² · 24 hours (40 ° C.) or less, preferably 25 g / m ² · 24 according to the moisture permeability test method of JIS Z 0208. Time (40 ° C.) or less.

  As a material for the moisture-proof sheet, a configuration in which a fibrous sheet is disposed on both sides of an aluminum foil via an adhesive or a configuration in which a fibrous sheet is disposed on both sides of a synthetic resin layer is desirable. As the fiber sheet, a thin paper made mainly of wood pulp, or a nonwoven fabric made of rayon, nylon, polyester, vinylon, acrylic, polypropylene, cupra, wood pulp or the like as raw material fibers is used. The thickness of the aluminum foil is not particularly limited. In addition, since aluminum foil has a risk of corroding in the long term, it is also effective to carry out anticorrosion treatment in advance using various commercially available anchor coating agents. The synthetic resin layer is made of polyolefin resin (low density or high density polyethylene, polypropylene, etc.), polyester resin, acrylic resin, or the like. You may stick to this composite of a synthetic resin layer and a fibrous sheet through a synthetic resin adhesive.

  The chelating agent used in the present invention is a multidentate ligand that coordinates to a metal ion to form a chelate compound, and is also called a metal sequestering agent. There are inorganic and organic (aminocarboxylate) chelating agents, but generally the latter organic. Chelating agents include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylenetetraminehexaacetic acid (TTHA), hydroxyethylidenebisphosphonic acid (HEDP) ) Etc. In the present invention, ethylenediaminetetraacetic acid, which is a colorless crystalline powder, which is particularly free of discoloration and contamination, is used. Among ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetraacetic acid dihydrogen disodium disodium dihydrate is particularly desirable. In addition to this chelating agent, there is polyphosphoric acid or the like as an agent having an effect of preventing discoloration contamination similar to this chelating agent.

In the configuration of FIG. 1, the proportion of ethylenediamine tetraacetic acid dihydrogen disodium disodium dihydrate added to the chelating agent added adhesive layer 4 on the veneer 3 side is 0.05 to 10% by weight, preferably 0.2 to 4%. 0% by weight. The application amount of this adhesive is 20 to 220 g / m ² , preferably 30 to 90 g / m ² . If the amount of the chelating agent used is small, the effect of preventing discoloration contamination is insufficient. Conversely, if the amount is too large, adhesion failure or the veneer itself may be discolored.

Moreover, in the structure of FIG. 2, the amount of active ingredients which apply | coat ethylenediaminetetraacetic acid dihydrogen disodium disodium dihydrate to the moisture-proof sheet 5 surface of the veneer 3 side is 0.1-10 g / m < ² >, Preferably it is 0. 4 to 4 g / m ² . Even in this case, if the effective amount of the chelating agent is small, the effect of preventing discoloration is insufficient, and conversely, if the amount is too large, the protruding plate itself may be discolored.

  The adhesive that bonds the veneer 3 and the moisture-proof sheet 5 is not particularly limited, and is selected from a vinyl acetate adhesive, a synthetic rubber latex adhesive, an aqueous vinyl adhesive, and the like. In the configuration of FIG. 1, a predetermined amount of a chelating agent is added to the adhesive and stirred, and then applied to the moisture-proof sheet surface and a veneer is attached.

  Further, the adhesive 6 for bonding the moisture-proof sheet 5 and the woody base material 7 is not particularly limited, and a vinyl acetate adhesive, an ethylene vinyl acetate adhesive, a polyurethane adhesive, and a synthetic rubber latex adhesive. , Selected from aqueous vinyl adhesives and the like. The adhesive is applied to the woody base material 7 and attached to the moisture-proof sheet 5.

  In some cases, the surface of the veneer 3 is colored or painted. 1 in the order of the veneer 3, the chelating agent-added adhesive layer 4, the moisture-proof sheet 5, the adhesive layer 6, and the wood-based substrate 7, or the veneer 3, the adhesive layer 6, and the chelating agent layer in the configuration of FIG. 8. After the surface is polished on the surface of the veneer 3 of the veneer-coated veneer 1 that is arranged and adhered in the order of the moisture-proof sheet 5, the adhesive layer 6, and the woody base material 7, the surface is polished, and then the fabric is colored with a colorant or clear-coated Alternatively, the coating film 2 may be formed by color coating or the like. The paint used is not particularly limited. Two-component polyurethane resin paint, unsaturated polyester resin paint, acrylic resin paint, phthalic acid resin paint, moisture-curing polyurethane resin paint, acrylic urethane resin paint, ultraviolet light It is selected from synthetic resin paints such as (UV) curable paints, oil-based paints such as oil finish paints, synthetic resin blend paints, natural resin paints such as nitrocellulose lacquer and cashew resin paints.

  The type of coating, the coating method, or the coating amount (coating film thickness) may affect the occurrence of discoloration and contamination. Minimizing the entry of moisture and moisture from the surface of the coating film 2 into the veneer 3 has the effect of delaying discoloration and occurrence of contamination, and can be expected to suppress the occurrence.

  Further, a warp-proof moisture-proof sheet having a structure in which fiber sheets are disposed on both sides of a synthetic resin, for example, may be attached to the opposite surface of the wood-based substrate 7 to the side of the projecting plate 3 via an adhesive. It does not impair the effect.

  In order to exert a sufficient anti-discoloration contamination effect in the present invention, it is not sufficient to insert a moisture-proof sheet, and the addition of a chelating agent to an adhesive or the application of a chelating agent alone is insufficient. It is. Only when the moisture-proof sheet is inserted and the chelating agent is disposed so as to be in contact with the surface portion of the veneer plate, a sufficient discoloration prevention effect is exhibited.

The decorative plates A, B, C, and D having the integrated laminated molding configuration described below were manufactured and subjected to the following evaluation test. First, decorative boards A and B are one embodiment of the present invention, a synthetic rubber latex adhesive is applied onto a plywood as a base material, and moisture-proof sheets X and Y are heat-pressure bonded. On this moisture-proof sheet X and Y, a 5% aqueous solution of chelating agent ethylenediaminetetraacetic acid dihydrogen disodium dihydrate dihydrate is applied (coating amount 20 g / m ² ) and dried. A system adhesive is applied, and a white oak veneer (0.22 mm thick) is placed on the adhesive and hot-pressure bonded. After polishing the veneer surface of the finished decorative board, a polyurethane resin coating was applied. For the decorative board A, a moisture-proof sheet X (in order, thin paper 23 g / m ² , aluminum foil 12 μm thick, thin paper 23 g / m ² ) is laminated and bonded via an adhesive, and the decorative board B A moisture-proof sheet Y (in order, thin paper 23 g / m ² , polyolefin resin film 40 μm thick, thin paper 23 g / m ² ) was used. In addition, the decorative board C is a comparative example, and a synthetic rubber latex adhesive was applied on the same plywood substrate, and the thin paper was heat-pressure bonded. A synthetic rubber latex adhesive was applied onto the thin paper, and a white oak veneer (0.22 mm thick) was placed thereon and bonded by heat and pressure. The veneer surface of the finished decorative board was coated with polyurethane resin after polishing. Furthermore, the decorative board D is also a comparative example, in which a synthetic rubber latex adhesive is applied on the same plywood substrate, and the moisture-proof sheet Y is bonded by heat and pressure. A synthetic rubber latex adhesive is applied onto the moisture-proof sheet Y, and a white oak veneer (0.22 mm thick) is placed on the adhesive and heat-pressure bonded. After polishing the veneer surface of the finished decorative board, a polyurethane resin coating was applied. The moisture-proof sheet Y used for the decorative board D is the same as that used for the decorative board B. The application amount of the synthetic rubber latex resin adhesive used for the decorative plates A to D is about 55 g / m ² .

  As an evaluation test method, the sample was left in a thermo-hygrostat set to 40 ° C. and a relative humidity of 95% for 17 days, and the discoloration contamination state of the surface veneer was observed. As a result, as shown in Table 1, in the decorative plates A and B of the present invention, no discoloration contamination of the veneer was observed. Moreover, in the decorative board C which is a comparative example, the whole changed to black brown after 4 days. The decorative board D is provided with a moisture-proof sheet. However, after 17 days, a blackish brown discoloration is observed around the specimen, and a sufficient discoloration prevention effect is not exhibited.

  FIG. 3 shows the veneer surface state after 17 days of the evaluation test. It can be seen that the discoloration of the decorative board C is remarkable and the discoloration of the decorative boards A and B is not.

Example 2 is a veneer-coated decorative plywood in which a plywood is used as a base material, and a veneer (white oak) is attached to the base material via an adhesive, and the evaluation test results thereof. The following decorative plates E, F and G were produced and subjected to an evaluation test. The decorative board E is one embodiment of the present invention. From the top layer, the coating film, the veneer, the adhesive layer, the chelating agent layer, the moisture-proof sheet X, the adhesive layer, and the wood-based substrate (plywood, 4 mm thickness) are arranged in this order. Has been placed. The decorative board F is a comparative example, and is disposed in the order of the uppermost layer, the coating film, the veneer, the adhesive layer, and the woody base material (plywood, 4 mm thickness). The decorative board G is also a comparative example, and is disposed in the order of the top layer, the coating film, the veneer, the adhesive layer, the moisture-proof sheet X, the adhesive layer, and the woody base material (plywood, 4 mm thickness). In any of the decorative plates, the paint is a polyurethane two-component paint and the coating amount is the same. The veneer is white oak (0.20 mm thick), the adhesive is a synthetic rubber latex resin, and the coating amount is about 55 g / m ² . As the chelating agent for the decorative board E, a 5% aqueous solution of ethylenediaminetetraacetic acid dihydrogen dihydrogen disodium dihydrate was applied to the veneer side of the moisture-proof sheet and dried, and the coating amount was about 20 g / m ² . Further, the moisture-proof sheet X is obtained by sequentially laminating a thin paper 23 g / m ² , an aluminum foil 12 μm thick, and a thin paper 23 g / m ² through an adhesive.

  As an evaluation test method, the sample was left in a thermo-hygrostat set to 40 ° C. and a relative humidity of 95% for 30 days, and the discoloration contamination state of the surface veneer was observed. The results are shown in Table 2. As shown in Table 2, the decorative board E according to the present invention showed a slight discoloration in a long-term test of 30 days, but extremely little discoloration contamination. The decorative board F as a comparative example is a decorative board made by a conventional manufacturing method, and the decorative board G as a comparative example is a decorative board in which a moisture-proof sheet is disposed and no chelating agent is used. In both cases, the blackish brown discoloration contamination spread on the surface of the veneer after 21 days.

  FIG. 4 shows the veneer surface state after 30 days of the evaluation test.

Example 3 is a veneer-coated decorative board having a medium-density fiberboard (MDF) as a base material, and a veneer (white oak) bonded to the base material via an adhesive, and its evaluation test results. . The decorative plates H, I, and J having the following laminated structure were manufactured and subjected to an evaluation test. The decorative board H is an embodiment of the present invention, and is arranged from the top layer in the order of paint, veneer, chelating agent-added adhesive layer, moisture-proof sheet X, adhesive layer, medium density fiberboard (MDF, 4 mm thickness). Yes. The decorative board I is also an embodiment of the present invention, and is arranged from the top layer in the order of paint, veneer, chelating agent-added adhesive layer, moisture-proof sheet Z, adhesive layer, medium density fiberboard (MDF, 4 mm thickness). Yes. The decorative board J is a comparative example, and is arranged in the order of the uppermost layer, the paint, the projecting board, the adhesive layer, and the medium density fiber board (MDF, 4 mm thickness). For both decorative boards H, I and J, the paint is a polyurethane two-component paint with the same coating amount, the veneer is white oak (0.25 mm thick), the adhesive is a synthetic rubber latex resin, and the coating amount is about 55 g / m. ² . In both cases, 1.2% ethylenediaminetetraacetic acid dihydrogen disodium dihydrate dihydrate is added as a chelating agent to an adhesive (synthetic rubber latex resin). The moisture-proof sheet X of the decorative board H is obtained by sequentially laminating thin paper 23 g / m ² , aluminum foil 12 μm thick, thin paper 23 g / m ² through an adhesive, and the moisture permeability (JIS Z) of the moisture-proof sheet X is laminated. 0208) is 0.1 g / m ² · 24 hrs (25 ° C.) or less. Further, the moisture-proof sheet Z of the decorative board I is obtained by sequentially laminating a thin paper 23 g / m ² , a polyester film 12 μm thick, and a thin paper 23 g / m ² through an adhesive. (JIS Z 0208) is 16.0 g / m ² · 24 hrs (25 ° C.).

  The evaluation test was based on a method of standing in a constant temperature and humidity chamber set at 40 ° C. and 95% relative humidity for 7 days, and observing the discoloration contamination state of the surface veneer. As shown in Table 3, the decorative boards H and I according to the present invention did not cause discoloration contamination. The decorative board J as a comparative example started discoloration contamination after 2 days, and after 7 days, blackish brown discoloration contamination occurred on the entire surface.

  FIG. 5 shows the state of the veneer surface after 7 days of the evaluation test.

Example 4 is a veneer-coated decorative board in which a veneer (white oak) is adhered using a medium density fiberboard (MDF) as a base material, and its evaluation test results. The decorative board K is an embodiment of the present invention, and is arranged from the top layer in the order of paint, veneer, chelating agent-added adhesive layer, moisture-proof sheet X, adhesive layer, medium density fiberboard (MDF, 3 mm thickness). Yes. The decorative board L is a comparative example, and is arranged in the order of a paint, a veneer board, an adhesive layer, and a medium density fiber board (MDF, 3 mm thickness) from the uppermost layer. The decorative board M is also a comparative example, and is arranged in the order of a paint, a veneer, a chelating agent-added adhesive layer, and a medium density fiberboard (MDF, 3 mm thickness). In both cases, the coating amount is a polyurethane two-component paint, the coating amount is white oak (0.22 mm thickness), the adhesive is a synthetic rubber latex resin, and the coating amount is about 55 g / m ² . The chelating agent-added adhesives of the decorative plates K and M are obtained by adding 1.2% ethylenediaminetetraacetic acid dihydrogen disodium dihydrate dihydrate as a chelating agent to a synthetic rubber latex resin adhesive. The moisture-proof sheet X is obtained by sequentially laminating thin paper 23 g / m ² , aluminum foil 12 μm thick, and thin paper 23 g / m ² through an adhesive.

  The evaluation test was based on a method of standing in a thermo-hygrostat set to 40 ° C. and relative humidity of 95% for 10 days, and observing the discoloration contamination state of the surface veneer. As a result, as shown in Table 4, the decorative board K of the present invention has no discoloration contamination in 10 days. The decorative boards L and M used as comparative examples showed discoloration contamination after 7 days and black-brown discoloration contamination almost entirely after 10 days. The color difference between the two decorative boards (color difference ΔE * ab before and after the test) is about 8, indicating that significant discoloration contamination has occurred. The decorative board K of the present invention has a color difference (color difference ΔE * ab before the test) of 0.34, and it can be seen that no discoloration contamination has occurred.

DESCRIPTION OF SYMBOLS 1 Veneer pasting board 2 Coating film 3 Veneer 4 Chelating agent addition adhesive layer 5 Moisture-proof sheet 6 Adhesive layer 7 Wood type base material 8 Chelating agent layer

Claims (6)

A veneer decorative veneer characterized in that an ultra-thin veneer of natural wood, a layer containing a chelating agent, a moisture-proof sheet, and a wooden base material are laminated and integrated in this order. The veneered decorative board according to claim 1, wherein the chelating agent is ethylenediaminetetraacetic acid. A layer in which the chelating agent is mixed with the adhesive is formed, the coating amount of the layer is 30 to 90 g / m ² , and the ratio of the chelating agent is 0.2 to 4.0% by weight. The veneered decorative board according to claim 2. The chelating agent is applied in the form of an aqueous solution (the amount of the chelating agent applied is 0.4 to 4.0 g / m ² ) and then dried, and is laminated through a veneer and an adhesive. The veneered decorative board according to claim 2, 5. The moisture-proof sheet has a structure in which a fibrous sheet is laminated on both surfaces of an aluminum foil, or a structure in which a fibrous sheet is laminated on both surfaces of a synthetic resin layer. Veneered decorative board. The veneer decorative sheet according to any one of claims 1 to 5, wherein the moisture-proof sheet has a moisture permeability (JIS Z 0208) of 25 g / m ² · 24 hours (40 ° C) or less.

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