JPH06240841A - Gypsum board - Google Patents

Abstract

PURPOSE:To peel wall paper stuck on a board surface completely. CONSTITUTION:Base paper 2 for a board is impregnated with a resin liquid, and the whole layers of the base paper 2 for the board are resinified. Consequently, the strength of the whole layers of the base paper 2 for the board is increased, and strength among the layers is equalized. Accordingly, even when wall paper 3 for decorating stuck on the surface of the base paper 2 for the board is peeled, the layers of the base paper 2 for the board do not peel off, and no base paper 2 for the board adheres on the wall paper 3 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gypsum board, and more particularly to a gypsum board with improved releasability for wallpaper for cosmetics.

[0002]

2. Description of the Related Art Gypsum board has been widely used as a ceiling material for general buildings since it is inexpensive in spite of its high fire resistance and sound insulation. The gypsum board is shown in Figure 1.
As shown in Fig. 3, the plaster 1 is used as a core material and both the front and back surfaces are covered with the base paper 2 for a board. However, in a place where design is especially desired during construction, a decorative wallpaper 3 is attached to the surface of the board. Therefore, the design is improved.

As an adhesive used for pasting the wallpaper 3, there is a starch paste mixed with a vinyl acetate adhesive, while the wallpaper 3 is a vinyl chloride resin film sheet (hereinafter referred to as a vinyl chloride sheet). .) Is used. A backing paper is laminated on the back surface of this PVC sheet in order to strengthen the adhesion to the board.In the work of sticking to the gypsum board, after applying the adhesive to this backing paper, sticking to the gypsum board Done.

[0004]

However, the wallpaper for makeup is tired after many years of use, and is therefore regularly replaced. For this purpose, it is necessary to remove the wallpaper 3 first, but even if only the wallpaper 3 is to be removed, the board base paper 2 adheres to the wallpaper 3 side and the board base paper 2 is sparsely removed on the gypsum board side. Generally, such a situation occurs (see FIG. 2). The reason is as follows.

As a result of papermaking, the board base paper 2 has a structure in which a plurality of layers having different properties are laminated. For example, in the case of a three-layered paper, a surface layer, a water stop layer, and an adhesive layer are formed from the surface side. Of these, the surface layer has a smooth and strong paper quality suitable for the finishing surface, but the adhesive layer is made to fluff a little to increase the adhesive strength with the internal plaster, and the production of gypsum board Sometimes paper fibers bite into the gypsum slurry and physically bond. As described above, since the base paper for board is made by papermaking, the adhesive strength between the layers is low, and the adhesive strength between the layers is also non-uniform because the properties of the layers are different. Thus, the surface of the gypsum board had to be uneven in the peeling condition of the base paper for the board.

Therefore, if the wallpaper is replaced with a new makeup wallpaper as it is, unevenness will occur on the surface. Therefore,
In order to correct this unevenness, conventionally, the work of applying putty to the surface of the gypsum board before applying a new wallpaper and applying the new wallpaper while making the surface smooth has been performed.

However, the work of applying the putty evenly is not easy, and the correction work is troublesome because it is necessary to lightly sand after the drying. Also,
There was also a problem that the construction period would be delayed by this amount because the paste cannot be replaced until the putty is dried.

The present invention has been developed and devised in view of the above-mentioned problems, and an object thereof is to provide a gypsum board capable of neatly removing wallpaper.

[0009]

The structure of the present invention for achieving the above object is a gypsum board having a surface coated with a base paper for a board, the base paper for a board being impregnated with a resin liquid. It is characterized by being.

Since the back surface of the board base paper is required to have good adhesiveness with gypsum, it is desired that the resin used has good hydrophilicity with gypsum (gypsum slurry). Examples of usable resins include urethane resin-based, silicon resin-based, and silane resin-based resins. The resin solution may be applied to the board base paper under the following conditions. Resin content (solid content): 30 to 40 parts by weight Solvent: Xylene, toluene, ethyl acetate, etc. Application amount: 0.5 g / m2 or more and 10 g / m2 or less Apply to the entire surface of the board base paper using such a resin solution . As a coating method in this case, a known method such as a roll coater method, a flow coater method or a spray coater method is adopted. As a result, the resin liquid permeates all the layers of the base paper for board, and after drying, all the layers are made into resin. And after carrying it into the gypsum board production line,
By a conventional method, a gypsum board coated on the front and back can be obtained.

[0011]

The effects of the present invention are as follows. Since the base paper for board is impregnated with the resin liquid so that all the layers of the base paper for board are made into resin, the interlayer strength of each layer can be higher than the adhesive strength between the base paper and cosmetic wallpaper. Therefore, when the decorative wallpaper is peeled off from the board raw paper, it can be neatly peeled off on the surface of the board raw paper. For this reason, it is possible to improve the work efficiency without requiring the correction work as in the past.

Further, if the amount of impregnation is adjusted so that only the base paper for board is resinified so that the resin liquid does not penetrate to the core of gypsum, the impregnation time of the resin is either before or during the production of the gypsum board. The gypsum board itself retains the fireproof performance as before.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. Before the board base paper is carried into the conventional gypsum board production line, the board base paper is impregnated with the resin liquid. The resin liquid used in this example was a moisture-curable urethane resin, and it was preferable to use a product number 329-006 manufactured by Kansai Paint Co., Ltd. as a raw material. It has a free isocyanate group (-NCO), and has the property of polymerizing and hardening by reacting with water in the gypsum slurry.

The resin solution is impregnated into the board base paper by impregnating the commercially available board base paper with the resin solution on the entire surface of either the front or back surface of the board base paper (both sides are impregnated). You may let me). By applying this resin solution, the resin solution penetrates into all layers of the board raw paper, and when dried, all layers of the board base paper become resin. by this,
The strength of the board base paper is reinforced by the resin, and the strength between the layers is made uniform.

The base paper for board thus obtained is carried into a gypsum board production line, and both sides of the gypsum are coated by a conventional method to obtain a desired gypsum board.

The gypsum board thus obtained was subjected to a fireproof test and a peeling test for inspecting the peeling condition of the cosmetic wallpaper, and was compared with a conventional gypsum board to which the decorative wallpaper was attached. . The results are shown in Table 1.

[0017]

[Table 1]

The conditions of the gypsum board used as the test object are as follows. Resin liquid (solid content): Moisture-curable urethane resin 30 parts by weight Application amount: 3.9 g / m2 Gypsum board thickness: 9 mm Decorative wallpaper: PVC sheet with backing paper laminated on the back Adhesive to wallpaper: Starch A mixture of glue and a vinyl acetate resin adhesive ◎ Fire protection test The test performed here is JIS A 1321, Sho 45.
It is a surface test prescribed in Declaration 1828, and the heating condition and the smoke generating condition were measured for the test body put into the heating furnace maintained at a constant temperature. As is clear from Table 1, it is confirmed that there is almost no difference in fireproof performance between the resin liquid-impregnated gypsum board of the example and the conventional gypsum board. ◎ Peeling test A cosmetic wallpaper was attached to the gypsum board of the example and the conventional gypsum board, and after the adhesive was completely dried, the wallpaper was peeled by hand. In the gypsum board of the example, the wallpaper could be cleanly removed from the surface of the board base paper impregnated with the resin liquid. As a result of performing this test on 10 test pieces, none of them caused partial peeling of the board base paper (pass rate 10/10). On the other hand, in the conventional gypsum board, non-uniform peeling of the board base paper was observed for all of the 10 sheets (pass rate 0/1.
0). (Comparative Example) In the present invention, the gypsum was coated with the resin solution impregnated into the base paper for board in advance, but the resin solution was impregnated after the gypsum was coated with the board base paper. An evaluation test as a base material was performed. When the resin solution is impregnated after the production of gypsum board, it is expected that the resin solution will penetrate the base paper for boards and further reach the core material of gypsum, which changes the performance as the base material of gypsum board. Whether or not it was evaluated especially in terms of fire protection performance. The results are shown in Table 2. However, the size of each test piece was adjusted so that the size of one piece is 40 × 40 (mm) and the thickness is 9 (mm), so that the thickness is 50 (mm) as a whole. .

[0019]

[Table 2]

The board of Comparative Example 1 is obtained by impregnating the base paper for board with the above resin liquid in advance to a solid content of 4.0 (g / m 2) and coating it with gypsum. The board of Comparative Example 2 is a gypsum board. Is produced and then impregnated with a resin liquid, and the impregnation amount is similarly impregnated with 15.0 (g / m 2). The test pieces of both comparative examples had the same size, and a base material test (fire prevention test) prescribed in Ministry of Construction Notification No. 1828 was performed on them. The heating condition is 0.92KWH on one side of the specimen.
The temperature in the furnace was maintained at about 750 ° C. for 30 minutes or more. As a result of inserting the test piece in that state, the difference in furnace temperature before and after the insertion of the test piece was measured. As a result, there was a temperature difference of 38 ° C. in Comparative Example 1, but 5 in Comparative Example 2.
The temperature difference was 7 ° C. That is, the thing of the comparative example 2 became out of the defined standard value (being 50 degrees C or less).

From these test results, it was found that when the resin liquid penetrates into the core material part of the gypsum board, it impairs practical use in terms of fire resistance as a base material. Incidentally, according to an experiment conducted by the applicant, the coating amount is about 30 in terms of solid content.
It has been confirmed that, when it exceeds (g / m2), the resin liquid penetrates into the gypsum core material and hinders fire prevention performance.

From the above, conversely, if the coating amount can be adjusted to be constant, it is possible to impregnate the resin liquid after the gypsum board is manufactured.

[Brief description of drawings]

[Figure 1] Cross-section of gypsum board

FIG. 2 is a sectional view showing a state in which the wallpaper is removed.

[Explanation of symbols]

 1 ... Gypsum 2 ... Board base paper 3 ... Wallpaper

Front page continuation (72) Inventor Sumio Nezu 15-2 Sumiyoshi-cho, Yokkaichi-shi, Mie Chiyoda Ute Co., Ltd.

Claims (1)

[Claims] 1. A gypsum board, the surface of which is coated with a base paper for board, wherein the base paper for board is impregnated with a resin liquid.