JP2006247935A - Decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decorative sheet characterized in that a surface layer and a base material layer are looked as a same color integrated layer even in a case that the color of decorative paper used in the surface layer and the color of kraft paper used in the base material layer are not same. <P>SOLUTION: In the decorative sheet obtained by integrating a plurality of papers impregnated with a thermosetting synthetic resin in a superposed state by hot press molding, a plurality of the papers are constituted so that decorative papers are superposed on both upper and under surfaces of at least one bleached kraft paper on a center side. The base material layer constituted of the bleached kraft paper is characterized in that the total light transmittance thereof after hot press molding is 30-90%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a decorative board obtained by integrating a plurality of paper impregnated with a thermosetting synthetic resin by hot press molding in a state where the papers are overlapped.

  A decorative board used as a furniture top plate or a building material has a decorative paper on one side of brown kraft paper, and multiple sheets of paper impregnated with thermosetting synthetic resin are integrated by hot pressing. Is generally obtained. Conventionally, this type of decorative board is a colored decorative board in which surface layers are laminated on both sides of a colored core layer, and the colored core layer is a decorative board in which the ash content of the colored core paper is 15 to 55% by weight. It is known (see Patent Document 1).

JP-A-9-136386

  Since the above-mentioned conventional decorative board has a different color tone between the surface layer and the base material layer (colored core layer), the boundary between the surface layer and the base material layer is clearly visually recognized when pasted as a top plate on a desk or the like. In other words, there is a problem that the design of the top surface (cut surface) of the top plate is significantly reduced.

  What improved this is what is called a "same color core decorative board." This "same color core decorative board" is a decorative board in which a surface layer having the same color as that of the base material layer is attached to both sides of the base material layer. As a manufacturing method of the “same color core decorative board”, A. A method in which the same paper as the decorative paper for the surface layer is used for the base material layer; A method of using kraft paper having the same color as the decorative paper on the surface layer for the base material layer, C.I. There is a method of impregnating bleached kraft paper constituting the base material layer with a resin having the same color as the decorative paper on the surface layer.

However, A. In the method in which the same paper as the decorative paper for the surface layer is used for the base material layer, the manufacturing cost of the decorative board is increased as compared with the case where kraft paper is used for the base material layer. Moreover, compared with the case where kraft paper is used for the base material layer, the decorative paper has a lower strength than the kraft paper, and the performance such as the bending strength and impact resistance of the decorative board is lowered.
B. In the method of using the kraft paper colored in the same color as the decorative paper of the surface layer as the base material layer, the kraft paper colored in that color must always be prepared according to the color of the decorative paper. In this case, there is a problem in that there is a limit to the number of colors that can be handled because the profit cannot be made unless the purchase lot is large. Moreover, since it is necessary to always prepare kraft paper corresponding to different colors of decorative paper, there is also a problem that the stock management cost of kraft paper increases.
In addition, C.I. In the method of impregnating the bleached kraft paper constituting the base material layer with the same color resin as the decorative paper on the surface layer, it is difficult to match the color of the decorative paper and the color of the resin. In addition, in the apparatus for impregnating the kraft paper with the resin, there is a problem that the resin colored in the same color as the decorative paper is mixed with the resin of other colors remaining in the apparatus.

  Accordingly, the present invention provides a decorative board in which the surface layer and the base material layer appear to be the same color even when the color of the decorative paper used for the surface layer and the color of the kraft paper used for the base material layer are not the same. With the goal.

Means for solving the above problems are the inventions described in the following (1) to (4).
(1) A decorative board obtained by integrating a plurality of paper impregnated with a thermosetting synthetic resin by hot-press molding in a stacked state,
The plurality of sheets are one or more bleached kraft papers on the center side, and decorative paper is superimposed on both upper and lower surfaces of the bleached kraft papers,
The decorative board, wherein the base layer composed of the bleached kraft paper has a total light transmittance of 30% or more and 90% or less after hot pressing.
(2) The decorative board according to (1) above,
A decorative board, wherein the bleached kraft paper has an ash content of 3% or less, and a thickness of the base layer composed of the bleached kraft paper after hot pressing is 2 mm or less.
(3) The decorative board according to (1) or (2) above,
The decorative layer is characterized in that the surface layer composed of the decorative paper has a total light transmittance of 30% or less after hot pressing.
(4) The decorative board according to any one of (1) to (3) above,
The decorative board, wherein the thermosetting synthetic resin is a melamine resin, diallyl phthalate resin, epoxy resin, or polyester resin.

  According to the present invention, there is provided a decorative board in which the surface layer and the base material layer appear to be the same color even when the color of the decorative paper used for the surface layer and the color of the kraft paper used for the base material layer are not the same. It becomes possible.

FIG. 1 is a cross-sectional view of a decorative board 10 according to the present embodiment. The upper side of FIG. 1 shows a state before the hot-pressure molding of the decorative board 10, and the lower side of FIG. 1 shows a state after the hot-pressure molding of the decorative board 10.
As shown in FIG. 1, the decorative board 10 is obtained by integrating a plurality of sheets of paper (decorative paper 12 and craft paper 14) impregnated with a thermosetting synthetic resin by hot pressing. It is. In the decorative board 10, the plurality of papers are obtained by superimposing one or more kraft papers 14 on the center side and decorative paper 12 on both upper and lower surfaces of the kraft paper 14. As the kraft paper 14, bleached kraft paper having an ash content of 3% or less is used. As the decorative paper 12, decorative paper having an ash content of 8% to 55% and a basis weight of 45 g / m ^{2 to} 160 g / m ² is used. In the decorative board 10 after hot-pressure forming, the central layer composed of one or more kraft papers 14 is referred to as a base material layer 20. In the decorative board 10 after hot pressing, the layers on the surface side constituted by the decorative paper 12 are referred to as surface layers 16 and 18.

[About thermosetting synthetic resin]
As the thermosetting synthetic resin impregnated into the decorative paper 12 or the kraft paper 14, a thermosetting synthetic resin that becomes transparent or translucent when cured after hot pressing is used. As such a resin, for example, a melamine resin, a diallyl phthalate resin, an epoxy resin, or a polyester resin can be used. Of these, melamine resin is most preferred because of its high transparency.

[About decorative paper]
In the decorative board 10 according to the present invention, as the decorative paper 12 constituting the surface layers 16 and 18, for example, a pigment or titanium oxide is incorporated to give a desired color, or the surface is further desired by gravure printing. A decorative paper having a basis weight of about 45 to 160 g / m ² can be used. The “decorative paper” refers to paper that has been subjected to a design, a pattern, coloring, or the like in order to enhance the design of the decorative board 10.

[About Kraft Paper]
In the decorative board 10 according to the present invention, bleached kraft paper is used as the kraft paper 14 constituting the base material layer 20. In general, kraft paper can be roughly classified into unbleached kraft paper and bleached kraft paper. However, in the decorative board 10 according to the present invention, bleached kraft paper having high whiteness is obtained. Is used. The definition of “bleached kraft paper” in the present invention is defined in Japanese Industrial Standard JIS-P-0001.

  As the kraft paper 14 constituting the base material layer 20, bleached kraft paper having an ash content of 3% or less is used. The reason is that if the ash content of the kraft paper 14 exceeds 3%, the total light transmittance of the base material layer 20 is lowered when the craft paper 14 becomes the base material layer 20 after hot pressing. It is. When the total light transmittance of the base material layer 20 is lowered, the visible light that has entered the base material layer 20 is prevented from being irregularly reflected inside the base material layer 20. In addition, "ash content" here is ash content measured based on Japanese Industrial Standard JIS-P-8128.

[About manufacturing method of decorative board]
A method for manufacturing the decorative board 10 will be described. As shown in FIG. 1, the decorative board 10 has one or more sheets of kraft paper 14 superimposed, the decorative paper 12 is overlapped on both upper and lower surfaces of the kraft paper 14, and the craft paper 14 and the decorative paper 12 are It can be manufactured by applying pressure while heating.

  Kraft paper 14 and decorative paper 12 are impregnated with a thermosetting synthetic resin. The method for impregnating the thermosetting synthetic resin is not particularly limited. For example, by applying or spraying an uncured thermosetting resin composition to the surface of the kraft paper 14 and the decorative paper 12. Can be impregnated.

The resin adhesion rate of the decorative paper 12 after impregnating the thermosetting synthetic resin is preferably 48 wt% or more and 55 wt% or less. The volatile content is preferably 4 wt% or more and 7 wt% or less.
The “resin adhesion rate” is a weight ratio of resin in impregnated paper (paper impregnated with resin), and is calculated by the following equation [1]. “Volatile matter” means the weight ratio of volatile components in the impregnated paper, and the result of measuring the weight of the impregnated paper after drying by weighing the impregnated paper in a drier at 120 ° C. ± 2 ° C. for 20 minutes. Is calculated by the following equation [2].
Resin adhesion rate (wt%) = ((impregnated paper weight−base paper weight) / impregnated paper weight) × 100 [1]
Volatile content (wt%) = ((impregnated paper weight−absolutely dry impregnated paper weight) / impregnated paper weight) × 100 [2]

  The resin adhesion rate of the kraft paper 14 after impregnating the thermosetting synthetic resin is preferably 38 wt% or more and 48 wt% or less. The volatile content is preferably 3 wt% or more and 9 wt% or less. The reason for this is that if the resin adhesion rate is less than 38 wt%, or if the volatile content is less than 3 wt%, the thermosetting synthetic resin does not spread over the entire kraft paper 14, so that This is because the material layer 20 is partially or entirely white, and as a result, the total light transmittance of the base material layer 20 is less than 30%. Moreover, if the resin adhesion rate exceeds 48 wt%, the excess thermoplastic synthetic resin impregnated in the kraft paper 14 will flow out during hot pressing. Further, if the volatile content exceeds 9 wt%, the kraft paper 14 after impregnating with the thermosetting synthetic resin blocks. Blocking means that the impregnated papers are in close contact before heating or pressurization.

  The base material layer 20 is a layer in which one or more kraft papers 14 impregnated with a thermosetting synthetic resin are integrated by hot pressing. The base material layer 20 needs to have a thickness of 2 mm or less and a total light transmittance of 30% or more and 90% or less. The “total light transmittance” here can be measured in accordance with JIS-K-7150.

  In order to manufacture the decorative board 10, the decorative paper 12 and the kraft paper 14 impregnated with the thermosetting synthetic resin are pressed while being heated by a press in a laminated state. As for the heating condition and pressurizing condition by the press machine, the temperature of the press surface is preferably 120 ° C. or higher and 150 ° C. or lower, and the press pressure is preferably 5 MPa or higher and 12 MPa or lower. When the temperature of the press surface is less than 120 ° C., the thermosetting synthetic resin is not sufficiently cured. When the temperature of the press surface exceeds 150 ° C., the thermosetting synthetic resin changes to yellow, and the decorative board 10 Because it becomes brittle. Also, if the pressing pressure is less than 5 MPa, the density of the decorative board 10 will not be uniform, and if the pressing pressure exceeds 12 MPa, the density of the decorative board 10 will be too high and the thickness will be insufficient. is there.

[How to use the decorative board]
FIG. 2 is a perspective view showing a state in which the decorative board 10 is attached to the upper surface of the core member 22. FIG. 3 is a cross-sectional view showing a state in which the decorative board 10 is attached to the upper surface of the core member 22. In addition, the core material 22 here is a board | plate material which is a target object to which the decorative board 10 is affixed. For example, a furniture top plate or the like corresponds to the core member 22.
As shown in FIGS. 2 and 3, the decorative board 10 according to the present invention is not particularly limited in its usage, but for example, it is used by attaching it to a top board or door of a shelf, a table, a system kitchen or the like. Is possible. Further, it can be used by being attached to a plate material for manufacturing various furniture, a plate material for internal or external application used for decoration, or an inner wall material of various buildings. The decorative board 10 can be used by being attached to the upper surface of the core material 22 with an adhesive or the like.

[About the effect of the decorative board]
As described above, the decorative board 10 has the base material layer 20 composed of one or more kraft papers 14, the thickness of the base material layer 20 is 2 mm or less, and the ash content of the kraft paper 14 is 3%. % Or less. The kraft paper 14 impregnated with the thermosetting synthetic resin has a resin adhesion rate of 38 wt% or more and 48 wt% or less, and a volatile content of 3 wt% or more and 9 wt% or less. The conditions at the time of hot-pressure forming with a press machine are a temperature of the press surface of 120 ° C. or more and 150 ° C. or less, and a press pressure of 5 MPa or more and 12 MPa or less. By forming the base material layer 20 under such conditions, the total light transmittance of the base material layer 20 becomes 30% or more and 90% or less. Further, the decorative board 10 is characterized in that the surface layers 16 and 18 are arranged on both sides with the base material layer 20 as a center and are integrally formed.

According to the decorative board 10 according to the present invention, when the total light transmittance of the base material layer 20 is as high as 30% or more and 90% or less, the following effects can be obtained.
As shown in FIG. 3, the visible light 26 that has entered the interior of the base material layer 20 from the wood surface 24 of the decorative board 10 diffuses while colliding with the fibers of the exposed kraft paper inside the base material layer 20. It hits the surface layer 16 and the surface layer 18 on the lower surface side. The visible light 26 that has entered from the end face 24 repeats such irregular reflection, and then jumps out of the end face 24 and is visible from the outside again. At this time, the visible light 28 that has jumped out from the end surface 24 has a color close to the surface layers 16 and 18 because of repeated irregular reflection. For this reason, the difference in color between the base material layer 20 and the surface layers 16 and 18 becomes difficult to distinguish, and since the sense of unity is high, an effect of being excellent in appearance can be obtained.

  In order to repeat the irregular reflection while the visible light 26 that has entered the base material layer 20 collides with the surface layer 16 on the upper surface side and the surface layer 18 on the lower surface side, the total light transmittance of the surface layers 16, 18 is increased. It is preferable that it is 30% or less. When the total light transmittance of the surface layers 16 and 18 exceeds 30%, the visible light 26 that has entered the inside of the base material layer 20 passes through the surface layers 16 and 18 and escapes to the outside. This is because the effect that the base material layer 20 and the surface layers 16 and 18 appear to be of the same color cannot be obtained sufficiently.

  Furthermore, since the decorative board 10 according to the present invention is configured to be vertically symmetrical in the thickness direction, there is almost no warpage, and an effect that the workability and handling properties are remarkably improved is also obtained.

[Example 1]
A light yellow decorative paper having a basis weight of 100 g / m ² mixed with 45% of pigment and titanium oxide was impregnated with a modified melamine resin initial condensate and then dried. This produced a decorative paper impregnated with a melamine resin having a resin adhesion rate of 53 wt% and a volatile content of 6 wt%. Further, a bleached kraft paper having a basis weight of 200 g / m ² and an ash content of 0% was impregnated with a modified melamine resin initial condensate and then dried. Thus, a kraft paper impregnated with a melamine resin having a resin adhesion rate of 44 wt% and a volatile content of 7 wt% was produced. Three sheets of kraft paper impregnated with melamine resin were superposed, and a laminate was prepared by superimposing decorative paper impregnated with melamine resin one by one on the upper and lower sides of the exposed kraft paper. Two sets of such laminates were prepared, and a 20 μm thick polypropylene film was interposed between the two sets of laminates. And two sets of laminated bodies which intervened this polypropylene film were pressurized, heating with a press. The pressing conditions at this time are a press surface temperature of 145 ° C., a pressing pressure of 8 MPa, and a pressing time of 30 minutes. Two decorative plates were obtained by cooling the two sets of laminates to room temperature and then removing them from the press. This decorative board was cut at an angle of 45 °, and the state of the end face was visually observed.

[Example 2]
A decorative board was prepared in the same manner as in Example 1 except that the number of kraft paper impregnated with melamine resin was changed from 3 to 8.

[Example 3]
A decorative board was produced in the same manner as in Example 1 except that the basis weight of the bleached kraft paper was changed to 100 g / m ² and the ash content was changed to 3%.

[Example 4]
Makeup in the same manner as in Example 1 above, except that the surface of a brown printing paper with a basis weight of 80 g / m ² mixed with 20% of pigment and titanium oxide was used to give a brown wood grain printing by gravure printing. A plate was made.

[Comparative Example 1]
A decorative board was produced in the same manner as in Example 1 except that the number of kraft paper impregnated with melamine resin was changed to 10.

[Comparative Example 2]
A decorative board was prepared in the same manner as in Example 1 except that the basis weight of the bleached kraft paper was changed to 100 g / m ² and the ash content was changed to 4%.

[Comparative Example 3]
A decorative board was produced in the same manner as in Example 1 except that the kraft paper impregnated with the melamine resin was changed to 35 wt% and the volatile content was changed to 1 wt%.

[Comparative Example 4]
A decorative board was prepared in the same manner as in Example 1 except that unbleached kraft paper having a basis weight of 200 g / m ² and an ash content of 0% was used, and decorative paper was disposed on both sides of the kraft paper.

[Comparative Example 5]
A decorative board was produced in the same manner as in Example 1 except that decorative paper was disposed only on one side of the exposed kraft paper.

[Comparative Example 6]
A decorative board was prepared in the same manner as in Example 1 except that a brown decorative paper having a basis weight of 80 g / m ² mixed with 5% of pigment and titanium oxide was used.

Table 1 shows the observation results of the face of the decorative board produced in Examples 1 to 4 and Comparative Examples 1 to 5, the thickness of the base material layer, the total light transmittance of the base material layer, and The total light transmittance of the decorative layer is shown.
As can be seen from the results of Examples 1 to 4 in Table 1, when the thickness of the base material layer is 2 mm or less and the total light transmittance is 30% or more and 90% or less, the decorative board It was found that the base layer and the surface layer seemed to be of the same color. On the other hand, as can be seen from the results of Comparative Examples 1 to 4, the thickness of the base material layer exceeds 2 mm, or the total light transmittance of the base material layer is 30% or more and 90% or less. When it was not in the range, it was found that the base layer and the surface layer did not appear to be the same color because the color tone of the base layer and the surface layer were different when the face of the decorative plate was observed. Furthermore, as can be seen from the results of Comparative Example 5, when the decorative paper is arranged only on one side of the exposed kraft paper, visible light is not sufficiently reflected inside the base material layer, so the end face is observed. When it was done, it turned out that the color tone of a base material layer and a surface layer differs.

It is sectional drawing of a decorative board, the state before hot-pressure shaping | molding of a decorative board is shown on the upper side, and the state after hot-pressure shaping | molding of a decorative board is shown on the lower side. It is a perspective view which shows the state which affixed the decorative board with respect to the upper surface of a core material. It is sectional drawing which shows the state which affixed the decorative board on the upper surface of the core material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Decorative board 12 Decorative paper 14 Kraft paper 16, 18 Surface layer 20 Base material layer 22 Core material 24 End face 26, 28 Visible light

Claims (4)

A decorative board obtained by integrating a plurality of sheets of paper impregnated with a thermosetting synthetic resin by hot press molding,
The plurality of sheets are one or more bleached kraft papers on the center side, and decorative paper is superimposed on both upper and lower surfaces of the bleached kraft papers,
The decorative board, wherein the base layer composed of the bleached kraft paper has a total light transmittance of 30% or more and 90% or less after hot pressing. The decorative board according to claim 1,
A decorative board, wherein the bleached kraft paper has an ash content of 3% or less, and a thickness of the base layer composed of the bleached kraft paper after hot pressing is 2 mm or less. The decorative board according to claim 1 or 2,
The decorative layer is characterized in that the surface layer composed of the decorative paper has a total light transmittance of 30% or less after hot pressing. The decorative board according to any one of claims 1 to 3,
The decorative board, wherein the thermosetting synthetic resin is a melamine resin, diallyl phthalate resin, epoxy resin, or polyester resin.

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