JP2006263977A - Decorative sheet and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a deep reinforcing layer to a woody fiberboard, which becomes the base material of a decorative sheet, up to its inside from its surface without bringing about the increase in cost or the environmental problem caused by the use of a solvent. <P>SOLUTION: A low-molecular isocyanate compound is applied to and penetrated in the surface of the woody fiberboard 1 as the base material and an aqueous adhesive is applied to the coated surface of the woody fiberboard to laminate a decorative material 3 on the woody fiberboard so that the isocyanate compound and the adhesive are cured at the same time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a decorative board using a wood fiber board as a base material and a method for producing the decorative board.

  Conventionally, as this type of decorative board, as shown in Patent Document 1, an impregnation layer impregnated with a polymer compound excluding a formalin resin is formed on the surface of a wood fiber board constituting a part of a substrate, A surface decorative material bonded to an impregnated layer with an adhesive layer is known.

In this case, the surface of the wood fiber board is impregnated with a polymer compound excluding formalin resin, and after curing, the surface decorative material is bonded with an adhesive layer, or the adhesive layer is in an uncured state of the polymer compound. The surface decorative material is bonded by the adhesive layer simultaneously with the curing of the polymer compound.
JP-A-9-225910

  By the way, in the thing of the said patent document 1, although the high molecular compound other than formalin is impregnated to the wood fiber board, since the viscosity of the high molecular compound is high, even if it heats after application | coating, a high molecular compound is a wood fiber. It is difficult to sufficiently penetrate the inside of the plate, and only the surface can be strengthened. It is inevitable that a large unstrengthened portion is formed. As a result, there is a problem that the unstrengthened portion absorbs water and swells. In order to increase the permeability of the polymer compound into the fiberboard, it is necessary to reduce the viscosity by using a solvent. However, the use of the solvent increases the cost and causes environmental problems.

  In addition, after applying the polymer compound to the fiberboard surface, when further applying an adhesive with a roll coater and spreader on the polymer compound remaining uncured on the surface, the polymer remaining on the fiberboard surface The compound adheres to a device such as a roll coater and is mixed with the adhesive, which makes it practically difficult to apply the adhesive.

  The present invention has been made in view of such various points, and the object of the present invention is to provide a wooden fiberboard serving as a base material for a decorative board from its surface without incurring cost increase or environmental problems due to the use of a solvent. It is to be able to form a deep reinforcing layer.

  In order to achieve the above object, in the present invention, not a conventional polymer compound but a low molecular weight isocyanate compound is applied and infiltrated into a wood fiber board to strengthen it, and a decorative material is laminated on this wood fiber board and bonded. I did it.

  Specifically, in the invention of claim 1, in the decorative board provided with a wood fiber board at least on the surface portion, a low molecular isocyanate compound is applied and penetrated on at least the surface of the wood fiber board. A decorative material is laminated on the fiberboard via a water-based adhesive, and the isocyanate compound that has penetrated the wood fiberboard reacts with both the moisture in the fiberboard and the water in the water-based adhesive and cures together with the adhesive. It is characterized by.

  According to the above configuration, the isocyanate compound is a low molecule and has a low viscosity of 30 to 500 mPa · s even without mixing a solvent or the like. Since this low viscosity isocyanate compound is used, the inside of the wood fiber board It penetrates into the wood fiber board easily without being diluted with a solvent, and after the penetration, it reacts with moisture in the wood fiber board to form a strong polymer compound. In addition, the isocyanate compound reacts and cures with the moisture in the aqueous adhesive on the surface of the fiberboard to produce a strong polymer compound, so that the adhesive itself for adhering the decorative material is also firmly fixed to the wood fiberboard. Therefore, the decorative material is also firmly fixed to the fiberboard. Further, since the isocyanate compound reacts with the moisture of the adhesive, the drying process for removing moisture can be shortened. In addition, since the isocyanate compound reacts even at room temperature, it may be left naturally, but when heated, the reaction is accelerated in a short time.

  Further, since it is not necessary to reduce the viscosity of the isocyanate compound with a solvent, there is no cost increase or environmental problem due to the use of the solvent.

  In the invention of claim 2, the wood fiber board does not contain a water repellent or waterproofing agent or contains 1% by weight or less based on the wood fiber.

  Thus, by using a wood fiber board that does not contain a water repellent or waterproofing agent or has a content of 1% by weight or less with respect to the wood fiber, the water repellency is eliminated from the wood fiber board, and the isocyanate compound becomes more It becomes easy to permeate, and more than the water repellent effect of the water repellent and waterproofing agent, the effect of the formation of a strong polymer compound by the reaction of the isocyanate compound that has penetrated into the wood fiber board with water is increased.

  In the invention of claim 3, the wood fiber board is essentially composed of an adhesive mainly composed of an isocyanate compound.

  As described above, when an adhesive mainly composed of an isocyanate compound is used as an adhesive in the wood fiberboard, the affinity with the isocyanate compound applied to the fiberboard surface for reinforcement is improved, and the applied isocyanate compound Becomes easier to penetrate.

  According to a fourth aspect of the present invention, in the method for producing a decorative board provided with a wood fiber board at least on the surface, a low molecular weight isocyanate compound is applied and permeated to at least the surface of the wood fiber board, and then an aqueous adhesive is applied. Then, the decorative material is laminated, and the wood fiber board and the decorative material are heated and pressed to simultaneously cure the isocyanate compound and the adhesive.

  This invention can achieve the same effects as those of the invention of the first aspect.

  As described above, according to the invention of claim 1 or 4, a low molecular weight isocyanate compound is applied and infiltrated onto at least the surface of the wood fiber board, and a decorative material is laminated by applying an aqueous adhesive, and the isocyanate compound is bonded. By making it harden together with the agent, the low-viscosity isocyanate compound penetrates into the wood fiberboard without diluting with a solvent, and reacts with the moisture in the wood fiberboard and the moisture in the aqueous adhesive on the fiberboard surface. It can be cured to produce a strong polymer compound, and the decorative material can be firmly fixed to the fiberboard together with the adhesive, and has excellent hardness and water resistance without causing cost increase or environmental problems due to the use of solvents. A decorative board is obtained.

  According to the invention of claim 2, the wood fiber board contains no water repellent or waterproofing agent or contains 1% by weight or less based on the wood fiber. It becomes easier for the compound to permeate, and it is possible to enhance the effect of the formation of a strong polymer compound by the reaction of the isocyanate compound that has penetrated into the wood fiber board with water.

  According to the invention of claim 3, the wood fiber board has an affinity for the isocyanate compound applied to the surface of the fiber board by making the adhesive mainly composed of the isocyanate compound essential. The applied isocyanate compound is more easily penetrated.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or its application.

  FIG. 1 shows a decorative board A according to an embodiment of the present invention. This decorative board A is laminated with a wood fiber board 1 and an adhesive layer 2 made of a water-based adhesive on the surface of the wood fiber board 1. And a decorative material 3 such as a decorative sheet and a wood veneer.

  The wood fiberboard 1 is made of, for example, a medium density fiberboard (MDF), and a reinforcing layer in which a low-molecular isocyanate compound penetrates the surface by coating and is cured by reacting with moisture in the wood fiberboard 1. 1a is formed. The isocyanate compound that has been applied and penetrated into the fiberboard 1 is not only cured by reaction with moisture in the fiberboard 1 to form the reinforcing layer 1a, but also reacts with moisture in the adhesive. The applied isocyanate compound is cured together with the aqueous adhesive.

  That is, when manufacturing this decorative board A, after applying a low molecular weight isocyanate compound to the surface of the wood fiber board 1 and infiltrating it, an aqueous adhesive is applied and the decorative material 3 is laminated, and these wood fiber boards are laminated. The decorative board A is manufactured by heat-pressing 1 and the decorative material 3 to simultaneously cure the isocyanate compound and the adhesive.

  The wood fiber board 1 to be used is not particularly limited. Further, the water content may be in the range of 5 to 13% by weight of the normal product. Further, the thickness of the wood fiber board 1 may be a normal MDF or the MDF that is torn in half or a quarter in the thickness direction, but is 0. It is necessary to be 5 mm or more.

  However, MDF using a certain amount of water repellent and waterproofing agent such as paraffin wax at the time of production deteriorates the permeability of the isocyanate compound. Therefore, MDF which does not use water repellent or waterproofing agent or addition of these It is necessary to use MDF whose amount is 1.0% by weight or less based on the raw wood fiber.

  Furthermore, if MDF uses an isocyanate compound as an adhesive between wood fibers during production, the permeability of the isocyanate compound is particularly good.

  The isocyanate compound that permeates into the wood fiber board 1 by the above application (the same applies to the isocyanate compound contained as an adhesive in the wood fiber board 1) is one having two or more isocyanate groups in one molecule. Diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate and the like, and these crude products may be used. In particular, crude diphenylmethane diisocyanate called PMDI is suitable from the viewpoint of reaction rate, cost, and safety. Moreover, you may use what gave the self emulsification property to the isocyanate compound, or improved the reactivity.

  These isocyanate compounds usually have a viscosity of 30 to 500 mPa · s and have good penetrability into the MDF without being dispersed by a solvent, and penetrate into the MDF immediately after coating. For this reason, even if the adhesive for adhering the decorative material 3 is applied by a roll coater or a spreader, the isocyanate compound does not adhere to the device, and workability is improved. In addition, in order to improve the permeability, the liquid temperature of the isocyanate compound can be raised to lower its viscosity, but it is not essential.

  In addition, the isocyanate compound is 100% active ingredient, does not require a drying step, and does not contain a solvent. Therefore, there is no problem in the working environment at the time of manufacture and the use environment of the decorative board A.

A reaction accelerator or the like may be mixed with these isocyanate compounds, but the viscosity of the coating solution needs to be suppressed within 500 mPa · s. The coating amount of the isocyanate compound is suitably 10 to 500 g / m ^2, while the effect is low is less than 10 g / m ^2, not only the manufacturing cost exceeds 500 g / m ² increases, heat curing In this case, excess resin oozes out and is wasted.

  Moreover, the kind of resin used for the water-based adhesive for sticking the decorative material 3 to the wood fiber board 1 (MDF) is melamine resin, urea resin, acrylic resin, polyurethane resin, water-based vinyl urethane resin, ABS resin, etc. These may be mixed and modified.

  The heat pressing of the decorative material 3 and the wood fiber board 1 is efficiently performed because the isocyanate compound and the adhesive are cured in a short time by heating at 100 to 150 ° C. Although the pressure is not particularly limited, when a pressure of 0.49 MPa or more is applied, the MDF is consolidated, the density is increased, and the surface hardness is further improved.

  Therefore, in this embodiment, the isocyanate compound reacts with the moisture of the adhesive and the moisture in the MDF at the time of heating by applying the adhesive to the wood fiber board 1 that has been coated with and penetrated with the isocyanate compound, The reaction cured product is very strong and has high water resistance. Further, since the isocyanate compound has a primer role, the amount of adhesive used can be greatly reduced. Therefore, in the decorative board A, the isocyanate compound penetrates into the wood fiber board 1 to increase the surface hardness, and the water resistance is remarkably improved.

(Other embodiments)
In the above embodiment, the low molecular isocyanate compound is applied and penetrated on the surface of the wood fiber board 1, but the low molecular isocyanate compound may be applied and penetrated on both the front and back surfaces.

  Moreover, in the said embodiment, although the decorative board A comprises the base material with which the decorative material 3 is bonded only with the wood fiber board 1, a base material is a composite material of a wood fiber board and a plywood, etc. at least, for example. What is necessary is just to make it have a wood fiber board in the surface part, and apply | coat and infiltrate an isocyanate compound to the wood fiber board surface of the base material.

  Furthermore, you may paint on the decorative surface of the decorative material 3 of the decorative board A in the said embodiment.

  Next, specific examples will be described.

Example 1
Prepare a base material in which a 9 mm South Sea plywood is combined with a 2.7 mm thick MDF (wood fiber board) that does not use water repellent and waterproofing agents such as paraffin wax, and crude diphenylmethane diisocyanate ( After applying 100 g / m ^{2 of a} viscosity of 200 mPa · s), 50 g / m ^{2 of} an aqueous vinyl urethane resin adhesive is further applied, and a 0.2 mm thick oak veneer is laminated thereon as a decorative material. Heat pressing was performed under the conditions of ° C, pressure of 0.98 MPa, and time of 3 minutes. Thereafter, the decorative surface was subjected to UV coating to obtain a decorative plate having a thickness of 12 mm.

(Example 2)
Instead of MDF in the base material of Example 1, 2.7 mm thick MDF using 0.7% by weight of paraffin wax having a melting point of 60 ° C. was used. Otherwise, the same processing as in Example 1 was performed to obtain a decorative board.

(Comparative Example 1)
Except not apply | coating crude diphenylmethane diisocyanate to MDF, the process similar to Example 1 was performed and the decorative board was obtained.

(Comparative Example 2)
Instead of MDF in the base material of Example 1, MDF having a thickness of 2.7 mm to which 1.5% by weight of paraffin wax having a melting point of 60 ° C. (approximately twice the amount of Example 2) was added was used. Otherwise, the same processing as in Example 1 was performed to obtain a decorative board.

(Comparative Example 3)
A decorative board was obtained in the same manner as in Example 1 except that 100 g / m ² of a moisture curable polyurethane resin (viscosity 2000 mPa · s) was applied instead of crude diphenylmethane diisocyanate.

(test)
The surface hardness (Brinell hardness) and the JAS standard class 1 immersion peeling test (Type 1) were performed on the above examples and comparative examples, and the swelling thickness amount and appearance change of the MDF part before and after the test were evaluated. The results are shown in Table 1.

According to Table 1, the Brinell hardness of the example is larger than that of the comparative example, and 30 N / mm ² or more is secured. In the results of the JAS Standard Type Immersion Peel Test in the Examples, the thickness expansion is 10% or less, and the appearance change is not observed in the crack of the lip.

  In Comparative Example 1, since the cosmetic material was directly pasted with an adhesive without impregnating the resin on the surface, the surface hardness and the thickness expansion were extremely inferior to those of other Comparative Examples. In Comparative Example 2, since the amount of wax was as large as 1.5% by weight compared to 0.7% by weight of the decorative board 2, the isocyanate compound was difficult to penetrate, and the resin was impregnated only in the surface portion. In Comparative Example 3, unlike a low-molecular-weight isocyanate compound, a high-viscosity and high-viscosity urethane resin was used, so that it was difficult to penetrate, and only the surface portion was impregnated with the resin. In these comparative examples, cracks were observed in the non-penetrating part.

  According to the present invention, it can be seen that a decorative board having a hard surface and excellent dimensional stability against water can be obtained.

  INDUSTRIAL APPLICABILITY The present invention provides a decorative board having a wood fiber board in which a strong polymer compound is generated not only on the surface but also inside the base material without causing an increase in cost and environmental problems due to the use of a solvent, and is extremely useful. Therefore, the industrial applicability is high.

FIG. 1 is a cross-sectional view showing a part of a decorative board according to an embodiment of the present invention.

Explanation of symbols

A decorative board 1 wood fiber board 1a reinforcing layer 2 adhesive layer 3 cosmetic material

Claims (4)

In a decorative board provided with a wood fiber board at least on the surface,
A low molecular isocyanate compound is applied and penetrated on at least the surface of the wood fiber board,
A decorative material is laminated on the wood fiber board via an aqueous adhesive,
A decorative board characterized in that an isocyanate compound that has penetrated into the wood fiber board reacts with both moisture in the fiber board and moisture in the aqueous adhesive and is cured together with the adhesive. The decorative board according to claim 1,
The wood fiber board does not contain a water repellent or waterproofing agent or contains 1% by weight or less based on the wood fiber. The decorative board according to claim 1 or 2,
The wood fiberboard is a decorative board characterized in that an adhesive mainly composed of an isocyanate compound is essential. In the manufacturing method of a decorative board provided with a wood fiber board at least on the surface part,
After applying and penetrating a low molecular weight isocyanate compound on at least the surface of the wood fiber board, applying a water-based adhesive and laminating a cosmetic material,
A method for producing a decorative board, comprising: heating and pressing the wood fiber board and the decorative material to simultaneously cure the isocyanate compound and the adhesive.

Images