JP2008214991A - Plywood for floor substrate, and floor material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain plywood which can reduce the dimensions of flapping unevenness occurring on a front layer at the time of water absorption. <P>SOLUTION: The plywood is manufactured by laminating a plurality of veneers on each other, and the thickness of a front layer veneer of the plywood is adjusted to be equal to 70 to 50% the thickness of the plywood in a finished state. Thus, at the time of water absorption, the flapping unevenness occurring on the front layer of the front layer veneer can be reduced. In this manner by employing inexpensive plywood made of planted trees, the plywood is effectively applicable to substrate plywood of a floor material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plywood for a floor base material suitably used as a base plywood for a floor material and a floor material using the same.

  Conventionally, Lauan plywood has been used as a base material plywood for floor materials. In recent years, it has become difficult to obtain Lauan due to the deterioration of the situation of raw wood, etc., and as a substitute plywood, the use of plywood produced from planted trees (early wood) as a base material plywood for flooring has been studied. However, plywood produced from planted trees is likely to have corrugated irregularities with a size that cannot be ignored on the surface due to water absorption. When unevenness is generated in the plywood for a floor base material, the unevenness may affect the decorative layer in the floor material thinly applied as a decorative layer on the plywood.

  In order to prevent blistering due to water absorption of wood and floor materials, conventionally, water-resistant wax, paraffin or the like has been applied to the mouth end surface (see, for example, Patent Document 1 and Patent Document 2). Adopting that means is considered as one solution for suppressing the occurrence of unevenness.

JP 2005-297262 A JP 2000-274054 A

  In the case of floor materials, at the time of floor construction, each floor material is attached to the floor base using an adhesive. Adhesives are sometimes used in combination with nailing. However, if water-resistant wax, paraffin, or the like is applied for the purpose of reducing water absorption as described above, when an aqueous adhesive is used as the adhesive, it becomes difficult to attach the adhesive, and sufficient adhesive strength can be obtained. There is no problem. Moreover, the operation | work which apply | coats wax etc. to a floor material mouthpiece surface etc. becomes an additional process to a series of floor manufacturing processes, and causes the fall of work efficiency.

  This invention is made | formed in view of the above situations, and makes it a subject to provide the plywood for floor base materials which can reduce that a wavy unevenness | corrugation arises on the surface even if it absorbs water. It is another object of the present invention to provide a composite base material and a floor material using the above-mentioned plywood for floor base material as a base material plywood, which does not cause any inconvenience even when being applied to a floor base.

  In order to solve the above-mentioned problems, the present inventors repeatedly perform a water absorption test on a plywood, and even under the same conditions, if the thickness of the plywood surface layer board (deck) is reduced, the undulation generated at the time of water absorption. It was found that the size of the irregularities gradually decreased. This was particularly noticeable when the veneer constituting the plywood was prepared from a plantation tree.

  The present invention is based on the above-mentioned knowledge, and the plywood for floor base material according to the present invention is adjusted to the thickness of the surface layer single plate of the plywood so that the thickness of the surface layer single plate is approximately 70 times the thickness when the plywood is finished. It is characterized by having a thickness of% to 50%.

  The plywood for floor base material according to the present invention is a plywood before adjusting the thickness of the surface single plate as described above, i.e., the surface plywood surface generated at the time of water absorption as compared with the plywood at the finish on the market. It was experimentally confirmed that the roughness of the wavy unevenness (the difference in height of the unevenness) was reduced.

  In the experiments by the present inventors, when the thickness of the surface layer single plate after the adjustment exceeds 70% of the thickness when the plywood is finished, a sufficient effect of reducing the wavy unevenness cannot be obtained. Further, when the thickness is adjusted to be thinner than 50%, the single plate layer of the base material plywood becomes close to an even number structure, and as a result, there is a possibility that inconvenience that causes the base material plywood to be warped or out of order.

  In the plywood for floor base material according to the present invention, the number of layers is arbitrary, and examples include 3-ply plywood, 5-ply plywood, and 7-ply plywood. In either case, grinding or the like is performed on the surface of the surface layer veneer, and a process for making the thickness of the surface veneer thinner than the finished one is performed. Moreover, in the plywood according to the present invention, the tree species of each veneer constituting each layer may be Lauan wood or a conventionally known plantation tree (early wood).

  The present invention also discloses a composite base material in which a wood fiber board is laminated on the surface layer single plate in the above-mentioned plywood for floor base material. The composite base material having this structure has higher surface smoothness due to the presence of the wood fiber board. Preferably, the thickness of the wood fiber board is about 0.5 mm to 3.0 mm. When a wood fiber board thicker than 3.0 mm is used, the surface roughness (unevenness) of the plywood for floor base material can be concealed by the thickness of the fiber board, and the superiority of the plywood for floor base material according to the present invention appears. Absent. A wood fiber board of less than 0.5 mm may not be able to conceal surface irregularities that are likely to be formed on a surface single board, although at a very low level upon water absorption. MDF is suitable as the wood fiber board.

  The present invention also discloses a floor material obtained by laminating a decorative layer on the above-mentioned composite base wood fiberboard. As described above, since the base composite material exhibits excellent surface smoothness even when water is absorbed, the floor material according to the present invention does not cause irregularities in the decorative layer even when water is absorbed. Even when a thin veneer veneer is attached as a decorative layer, a floor material with high surface smoothness can be obtained.

  In addition, since the floor material according to the present invention maintains the surface smoothness even when it absorbs water, it is not necessary to take measures such as applying a water-resistant wax to the end of the mouth in order to prevent water absorption. Therefore, it is possible to eliminate an extra work step of wax application and firmly adhere to the floor base using a water-based adhesive.

  According to the present invention, even when water is absorbed, a plywood for floor base material capable of suppressing the formation of wavy irregularities on the surface of the surface layer veneer, and a wood fiber board is laminated on the plywood for floor base material And a floor material using the composite base material.

  Corrugated irregularities due to water absorption are thought to be caused by stress accumulated during plywood production, growth stress of plywood raw wood, wood grain, etc., but considering that all of these stresses are released when plywood is finished. Therefore, it is very difficult to manufacture plywood. On the other hand, it is necessary to use all kinds of planted trees (early-grown materials) as materials for plywood. Under such circumstances, according to the present invention, it is possible to reduce the occurrence of corrugated irregularities on the plywood by a relatively simple method, and to transfer the low-quality and low-priced plywood to the base material plywood for the floor material. A practical effect.

  Hereinafter, although the present invention is explained based on an example, it is natural that the present invention is not limited to this example.

  As the test plywood, a 5-ply plywood made of a single plate of birch material, which is a commercially available finished plywood, was used. The total thickness is 11.4 mm, and the thickness of each layer is as follows: surface layer (deck): 1.6 mm, second layer: 3.3 mm, third layer: 1.6 mm, fourth layer: 3.3 mm, Fifth layer: 1.6 mm.

[Example 1]
Ten test plywood surface plates (tops) were ground with a wide belt sander to reduce the thickness by about 30% to prepare 1.12 mm. After immersing it in 20 ° C. warm water for 24 hours, the surface roughness difference (μm) of the surface layer single plate was measured using a rough surface roughness measuring instrument (SURFCOM130A manufactured by Tokyo Seimitsu Co., Ltd.). The measurement was performed at an evaluation length of 50 mm and a measurement speed of 0.6 mm / sec. The average value of 10 pieces is shown in Table 1.

[Example 2]
Ten test plywood surface plates (tops) were ground with a wide belt sander to reduce the thickness by about 50% and prepared 10 pieces having a thickness of 0.80 mm. After immersing it in warm water in the same manner as in Example 1, the surface unevenness difference (μm) of the surface single plate was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
After grinding the surface plywood (top) of the test plywood as it is in the same manner as in Example 1 without grinding it, the surface unevenness difference of the surface plywood (as in Example 1) for 10 of them μm). The results are shown in Table 1.

[Comparative Example 2]
After laminating 0.6 mm thick MDF on the surface plywood of the test plywood and 0.3 mm thick veneer on it, 10 painted floor materials were made. After being immersed in warm water, the surface unevenness difference (μm) on the surface of the veneer was measured in the same manner as in Example 1. The results are shown in Table 1.

[Discussion]
Compared with the test plywood which is Comparative Example 1, it can be seen that the surface unevenness difference is smaller in Examples 1 and 2 in which the thickness of the surface layer veneer (deck) is reduced. The amount of reduction becomes smaller as the thickness of the surface layer becomes thinner. From this, the thickness of the surface plywood of the plywood is adjusted so that the thickness of the surface plywood is 70% to 50% of the thickness when the plywood is finished. It can be seen that unevenness is suppressed.

  The floor material in Comparative Example 2 was formed by laminating the MDF and the veneer on the test plywood, so that the wavy irregularities generated by the water absorption by the plywood did not appear on the surface of the veneer as in Example 1. The surface roughness difference is similar. From this, when the plywood of Example 1 or 2 is used as a floor material plywood, it can be predicted that the wavy irregularities appearing on the surface of the floor material after water absorption are further reduced.

Claims (4)

  A plywood for a floor base material, characterized in that the thickness of the surface layer single plate is adjusted to approximately 70% to 50% of the thickness when the plywood is finished by adjusting the thickness of the surface layer single plate of the plywood.   The plywood for a floor base material according to claim 1, wherein the veneer is prepared from planted trees.   The composite base material by which a wooden fiber board is laminated | stacked on the said surface layer single board in the plywood for floor base materials of Claim 1 or 2.   A floor material obtained by laminating a decorative layer on the wood fiberboard of the composite substrate according to claim 3.