JP2004181755A - Interior surface material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which, in order to obtain MDF convexly warped in advance, can form the specific gravity difference between inside and outside surfaces simply without passing through a complex process such as press temperature setting or bedrock layer cutting. <P>SOLUTION: In an interior surface material, when a medium density fiber board having bedrock layers of 0.5-1.5 on the inside and outside surfaces is molded, the inside and outside surfaces of a woody fiber mat have different water contents, and a surface higher in water content is warped convexly by the difference of expansion stress when it is hot-pressed. The woody fiber mats are piled into at least two layers. When the medium density fiber board having the bedrock layers of 0.5-1.5 on the inside and outside surfaces is molded, the water contents of the mats located at least on the inside and outside surface of the fiber board are different, and a surface higher in water content is sometimes warped convexly by the difference of expansion stress when it is hot-pressed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a building material such as a floor material or a tatami core material using a medium-density fiberboard, and relates to a method of processing the material into a convex warp in advance.
[0002]
[Prior art]
BACKGROUND ART Medium density fiberboard (hereinafter, referred to as “MDF”) has been widely used as a building material (hereinafter, referred to as “face material” in the present invention) such as a floor material or a tatami core material. Its advantages are that it uses less natural material than plywood or the like and is suitable for natural protection, and that it has better surface scratch resistance than plywood base material.
[0003]
On the other hand, in order to prevent concave warpage (reverse warpage) caused by temperature change and humidity change after laying, convex warpage is also performed in advance at the molding stage. As the conventional methods, (1) a method of giving a difference in the pressing temperature between the front and back of the MDF in the pressing step (for example, see Patent Document 1), and (2) a method of cutting and removing only one surface side of the MDF to a predetermined thickness ( For example, see Patent Literature 2 and Patent Literature 3).
[0004]
According to the method (1), a difference in specific gravity is formed between the front and back rock layers of the MDF due to the difference in press temperature, and the surface material convexly warped toward the high specific gravity surface due to the difference in expansion stress is used in the method (2). According to this, by cutting and removing only one surface side, collapse of the stress balance occurs on the front and back surfaces of the MDF, and as a result, a surface material that is convexly warped to the non-cutting removal side can be obtained. In the case where the thus obtained convexly warped MDF is used as a core material for tatami, for example, the tatami mat is flattened by its own weight, and the tatami mat can be laid without unevenness. The concave warpage can be surely prevented even when the humidity changes.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-167811 [Patent Document 2]
JP-A-6-155422 [Patent Document 3]
JP-A-2002-227387
[Problems to be solved by the invention]
However, the conventional manufacturing method has the following problems. That is, the method (1) has a problem that the press process at the time of MDF molding is complicated, and the MDF production efficiency is reduced. In the method (2), there is a problem in that the number of steps for cutting and removing increases, the manufacturing process becomes complicated, and the face material becomes thinner by the amount of cutting and removing, so that a desired strength cannot be secured.
[0007]
The present invention has been made in view of the above-described problems, and an object thereof is to obtain a MDF that has been previously convexly warped, without having to go through complicated steps such as setting a press temperature and cutting and removing a bedrock layer. Another object of the present invention is to provide a manufacturing method capable of forming a specific gravity difference between the front and back surfaces.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides an indoor surface material such as a floor material, a tatami mat core material, and a ceiling material made of a medium-density fiberboard in which a rock layer is formed on each of the front and back surfaces. The surface rock layer is configured to be convexly warped by increasing the density of the surface rock layer from that of the back rock layer. The convex warpage is flattened by the weight of the surface material itself after the construction. In addition, since the surface rock layer has a strong stress that causes a convex warpage, even if the room is heated or dried after the laying, it is possible to avoid a concave warp.
[0009]
By setting the outermost specific gravity difference between the surface rock layer and the back rock layer caused by the difference in water content to be 0.1 to 0.6, a surface material having an appropriate convex warpage height can be obtained.
[0010]
By setting the average specific gravity of the whole to 0.35 to 1.0, the face material can be thinned and the strength can be increased.
[0011]
By setting the substantially center portion of the face material to the maximum warp height, the gravity distribution is performed evenly over the entire circumference, and the flatness is improved at the time of laying.
[0012]
In the present invention, as a method of manufacturing such a room facing material, in molding a medium-density fiberboard having a rock layer of 0.5 to 1.5 on the front and back surfaces, the moisture content of the wood fiber mat is measured on the front and back surfaces. Differently, a means for making a surface having a high moisture content convex and warp due to a difference in expansion stress at the time of hot pressing was used.
[0013]
Further, as another manufacturing method, at least two layers of wood fiber mats are superimposed, and when forming a medium density fiber board having a rock layer of 0.5 to 1.5 on the front and back surfaces, at least the surface of the medium density fiber board is formed. A means was used in which the moisture content of the wood fiber mats located on the back surface was made different, and the surface having a high moisture content was convexly warped due to the difference in expansion stress at the time of hot pressing.
[0014]
By adjusting the water content and the heat and pressure conditions, the outermost specific gravity difference between the front and back rock layers is set to 0.1 to 0.6, the maximum warp height is set to approximately the center, and the average specific gravity is set to 0.1. It can be set to 35 to 1.0, and the operation and effect are as described above.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described. Means for changing the moisture content of the wood fiber mat during MDF molding is, for example, drying using only a drying machine or the like on only one side of the wood fiber mat. A method of lowering the water content of only one side, or a method of giving water using a sprayer or an applicator only on one of the front and back sides of the wood fiber mat, and increasing the water content only on one side. Can be. However, the degree of drying and the amount of water to be applied to the wood fiber mat at the time of MDF molding are not particularly limited, and these conditions can be adjusted according to the required convex warpage height.
[0016]
It is also possible to mold the face material of the present invention by stacking two or more layers of wood fiber mats. When two layers of the wood fiber mat are formed by laminating them, the layers are heated and pressed at different moisture contents. On the other hand, in the case where three or more layers of the wood fiber mat are laminated and molded, the moisture content of at least the front and back layers is made different. The subordinate concepts include (1) the moisture content of each layer is different, (2) the moisture content of only one layer is different, and (3) the moisture content is gradually increased or decreased in one direction. What is used as the wood fiber of the wood fiber mat can be selected from known ones according to the use and purpose of the face material. The technical idea of the present invention includes adopting the same wood fiber for all the layers and adopting different wood fibers for each layer.
[0017]
On the other hand, it is preferable to laminate or coat a sheet or resin on a part or the whole of the convex warp face material manufactured by the above method. This is because the structure is such that the moisture absorption or release of the MDF is suppressed to prevent the expansion and contraction of the MDF or to protect the MDF surface. Examples of such sheets include resin impregnated sheets, natural wood veneers, artificial veneers, resin coated sheets, synthetic resin sheets, aluminum sheets, aluminum sand sheets, polysand sheets, and the like, and resins include urethane resins and epoxy resins. , PET resin, polyethylene resin and the like. When the sheets and the like are provided on both the front and back surfaces of the MDF, it is not always necessary to use the same type on both the front and back surfaces. It is also effective as a composite material bonded to plywood and ceramic boards.
[0018]
Furthermore, in the case of manufacturing a floor material, a tatami mat core material and a ceiling material using a convexly warped MDF as a base material, it is only necessary to adopt a configuration in which the MDF is flattened by its own weight after construction. In the case of horizontal construction, it is necessary to make the upper surface side convex. In other words, the floor material can be laid without any unevenness on the finished floor surface by making the convex warp surface on the indoor side similarly to the core material for tatami mats. An advantage of exhibiting a certain surface scratch resistance performance can be obtained. On the other hand, in the case of the ceiling material, there is an advantage that, by constructing the interior side as a concave warp, as opposed to the tatami mat or the floor material, the bending generated by the weight of the ceiling material is offset and the finished ceiling surface can be flattened.
[0019]
【The invention's effect】
As described above, according to the present invention, it is possible to form the outermost specific gravity difference of 0.1 to 0.6 between the front and back rock layers by changing the water content of the wood fiber mat at the time of MDF molding. It becomes easy to manufacture a flooring material and a tatami core material in which the surface having the rock layer on the higher specific gravity side is convexly warped due to the difference in expansion stress. In addition, by setting the convex warpage to the maximum warp height at the substantially central portion of the MDF, the workability in the case where they were constructed was improved, and the finished surface could be further flattened.

Claims (9)

A floor material made of a medium density fiberboard having a rock layer formed on each of the front and back surfaces, a room material such as a tatami mat core material, a ceiling material, and the like, wherein the density of the surface rock layer is higher than that of the back rock layer by increasing the density. An indoor surface material characterized in that the surface rock layer is convexly warped. The indoor facing material according to claim 1, wherein the outermost specific gravity difference between the surface rock layer and the back rock layer caused by a difference in the moisture content of the mat before molding is 0.1 to 0.6. The indoor facing material according to claim 1 or 2, wherein the average specific gravity of the whole is 0.35 to 1.0. 4. The indoor panel according to claim 1, wherein the substantially central portion has a maximum warp height. At the time of molding a medium-density fiberboard having a rock layer of 0.5 to 1.5 on the front and back surfaces, the water content of the wood fiber mat is made different between the front and back surfaces, and the difference in the expansion stress at the time of hot pressing causes the difference in the water content. A method for manufacturing indoor facing materials in which high surfaces are convexly warped. Two or more layers of wood fiber mats are superimposed, and at the time of molding a medium density fiber board having a rock layer of 0.5 to 1.5 on the front and back surfaces, the wood fiber mats located at least on the front and back surfaces of the medium density fiber board are A method for producing an indoor facing material in which the moisture content is different and the surface having a high moisture content is convexly warped due to a difference in expansion stress at the time of hot pressing. The method for manufacturing an indoor facing material according to claim 5 or 6, wherein the outermost specific gravity difference of the front and back rock layers is set to 0.1 to 0.6. The method according to claim 5, 6 or 7, wherein the maximum warp height is set substantially at the center. The method for manufacturing a room material according to any one of claims 5 to 8, wherein the average specific gravity is set to 0.35 to 1.0.