JP2003291121A - Method for manufacturing gypsum board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a gypsum board which shows superior strength and presentable appearance by preventing the release of a gypsum core from a base paper for the board from occurring even when a large irregular pattern is formed. <P>SOLUTION: A slurry obtained by kneading a material for the gypsum core 11 with water is cast into a gap between the base papers 12 for the board which form the face and back of the gypsum board 10. After that, in a process in which the slurry is cured, a plate die P traveling in accordance with the velocity of a belt conveyor is pressed. Since the gypsum board 10 is patterned by the plate die P in a process in which the chemical reaction of a gypsum dihydrate contained in the slurry is not in full progress, a desired profoundly irregular pattern 13 is obtained. In addition, the gypsum core 11 and the base paper 12 are not separated from each other at a spot where the irregular pattern 13 is formed by forming the irregular pattern 13. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a gypsum board.

[0002]

2. Description of the Related Art In recent years, gypsum board has been widely used as a building material which is inexpensive and rich in fire protection. On the other hand, in order to use the gypsum board as a waist wall or the like, there is a demand for a surface having a relatively large uneven pattern. As a method for producing a gypsum board having such a large uneven pattern, conventionally, a gypsum slurry is poured between base papers for a board, and the gypsum core material is almost completely dried so that the water content of the gypsum core material is 3% or less. There was a method of cutting into the size of, and then performing an embossing press.

[0003]

By the way, when the gypsum slurry is hardened to form a gypsum core material, a chemical change occurs from calcined gypsum in a slurry state to dihydrate gypsum in the shape of needles.
The gypsum core material and the board base paper are joined by binding the gypsum dihydrate to the fibers of the board base paper so as to be intertwined with each other. However, after the gypsum slurry is completely hardened as in the above-mentioned conventional method, when embossing press is performed to give a deep uneven pattern, the entanglement between the needle crystals of the gypsum core material and the fibers of the board base paper is torn. There is a problem that the base paper for board is peeled from the gypsum core material. If the base paper for the board is peeled off in this manner, the strength of the gypsum board is reduced, and the uneven pattern becomes unclear.

In order to avoid the above problems, there is also a conventional method in which steam is applied to the gypsum board in which the gypsum slurry is hardened and then the embossing press is performed.
Since most of the calcined gypsum is embossed after changing to dihydrate gypsum, it is not suitable for forming deep uneven patterns.
The essential solution to prevent the peeling of the gypsum core material and the board base paper could not be achieved. The present invention has been completed based on the above circumstances, the production of gypsum board excellent in strength and appearance by preventing peeling between the gypsum core material and the board base paper even if a large uneven pattern is applied. It is an object of the present invention to provide a gypsum board manufacturing method that can be used.

[0005]

As a means for achieving the above object, the invention of claim 1 provides a slurry prepared by mixing calcined gypsum, which is a raw material of a gypsum core material, with water. In a method for producing a gypsum board, which is poured between base papers for forming a back surface, formed into a predetermined shape, and then dried, an embossing pattern of the gypsum board by embossing in a state where the water content of the gypsum board is 50% or less It has a feature in that it is attached.

A second aspect of the invention is characterized in that, in the first aspect, the second embossing is performed in a state where the water content of the gypsum board is 50% or less.

A third aspect of the present invention is characterized in that, in the first or second aspect, drying is performed at a drying temperature of 100 ° C. or lower after the step of embossing.

[0008]

<Operation and effect of the invention><Invention of claim 1> Since embossing is performed in a process in which the reaction of gypsum dihydrate in the slurry does not proceed sufficiently, the base paper for gypsum and the gypsum core material are provided after the uneven pattern is formed. To be joined. Therefore, it is possible to manufacture a gypsum board excellent in strength and appearance without causing the base paper for board in a portion having an uneven pattern as in the past to be separated from the gypsum core material.

<Invention of Claim 2> Even when the uneven pattern of the gypsum board is slightly returned and deformed, the second embossing is performed, so that the contour shape of the uneven pattern can be made clearer.

<Invention of Claim 3> 10 after the embossing step
Since it is dried at a relatively low temperature of 0 ° C. or less, peeling due to thermal expansion of the board base paper can be suppressed, and the appearance quality can be protected.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a base paper for board (hereinafter, simply referred to as “base paper”) for forming front and back surfaces of a gypsum board is a slurry formed by kneading the raw material of the gypsum core material 11 and water.
It is a manufacturing method for manufacturing the gypsum board 10 by pouring it between 12 and FIG. 1 shows a schematic view of a manufacturing line of the gypsum board 10 according to the present embodiment. Hereinafter, the manufacturing method will be described in detail. First, water is added to a calcined gypsum (hemihydrate gypsum), an adhesion aid such as starch, a foaming agent, an admixture such as an inorganic fiber, and the mixture is kneaded with a mixer M to form a slurry. In this embodiment, 76 parts by weight of water and 0.4 parts by weight of oxidized starch are mixed with 100 parts by weight of calcined gypsum (hemihydrate gypsum), and a trace amount of polyoxyethylene alkyl ether sulfate foam, glass fiber, and acceleration of setting. Agents and set retarders were added.
The calcined gypsum is made from gypsum dihydrate obtained from natural gypsum or chemical gypsum, and the gypsum dihydrate is about 150 ° C to 200 ° C.
The one obtained by firing at the temperature of was used. As the setting accelerator, fine powder of gypsum dihydrate or potassium sulfate was used.

The slurry kneaded by the mixer M is poured onto the lower raw paper 12L whose both sides in the width direction are bent and bent. When the slurry is poured, the upper base paper 1
After 2U is applied and bonded, it passes through the thickness adjusting plate F to be molded into a predetermined thickness. In this embodiment, the gypsum board 10 is shaped by the thickness adjusting plate F to have a thickness of 15 mm. Further, in order to bend and bend both sides of the base paper 12, fold grooves are formed in advance on both sides of the base paper 12 by jewels (scoring).

The gypsum board 10 which has passed through the thickness adjusting plate F
Is transferred to the pattern forming machine S and the plate-shaped die P is pressed against it. This plate-shaped mold P is vertically movable in the pattern forming machine S and slidable along the longitudinal direction, and the lower surface thereof is a molding surface, and the plaster before the internal slurry is hardened. A desired pattern is applied to the board 10.

The plate-shaped mold P is pressed at a relatively slow speed so that the gypsum core material (slurry in the hardening process) and the base paper are not destroyed. Furthermore, the plate-shaped die P is moved in the feeding direction of the gypsum board 10 at the same speed as the feeding speed of the belt conveyor while being pressed. As a result, the embossing of the gypsum board 10 is performed over a period of time until it passes through the pattern forming machine S. Here, the water content of the gypsum board when the plate-shaped die P starts pressing is 30.
It is about 50%. By the time the pressing by the plate-shaped mold P is completed, the calcined gypsum in the slurry chemically changes to gypsum dihydrate and entangles with the fibers of the base paper 11. As a result, the gypsum core material 11 and the base paper 12 for board are joined together in a shape along the uneven pattern 13. Here, the water content of the gypsum board 10 when passing through the pattern forming machine S after forming the uneven pattern 13 is 30 to 50%, and does not easily return and deform even when the pressing of the plate-shaped die P is released. It has hardened. In this embodiment, the line speed of the gypsum board production line is 3 m / min, the time during which the embossing process is performed is 5 to 15 minutes, and the pressing pressure is 5
It is kg / cm ² . When the plate-shaped mold P is pressed for a predetermined time, the plate-shaped mold P moves up to a predetermined position, and the plate-shaped mold P is pressed to the next position.

The embossed gypsum board 10 is
Transferred to the dryer D. In the dryer D, drying is performed at a drying temperature of 100 ° C. or lower. Here, in this embodiment, 1
The gypsum board 10 is dried at a temperature of 00 ° C. or lower to lower the temperature than the normal drying temperature (160 ° C. to 100 ° C.). This suppresses the base paper 12 from expanding and deforming and floating. Further, since the dryer D uses the waste heat of the dryer used in another manufacturing line (not shown) as a heat source, it is not necessary to use a separate heating device. After the drying is completed, when the necessary portion is cut by the cutter C, the gypsum board 10 having the concavo-convex pattern 13 as shown in FIGS. 2 and 3 is obtained.

The gypsum board 10 manufactured as described above is pressed in a so-called semi-dry state with a water content of 50% or less, and a pattern is applied before it is converted into dihydrate gypsum.
A desired deep concavo-convex pattern 13 is obtained. As a result, the gypsum core material 11 and the base paper 12 are formed in a state in which the good entanglement is maintained, so that the base paper does not float and has a clear contour pattern.

In this embodiment, after the plate-shaped die P is pressed, the gypsum slurry is hardened, and then the secondary molding may be performed before the drying step. In this case, the water content of the gypsum board 10 is 5 even if the secondary molding is performed.
It is desired to be 0% or less. By performing the secondary molding in this way, the return deformation of the gypsum core material 11 can be limited and the concavo-convex pattern 13 can be made clearer.

<Second Embodiment> The present embodiment differs from the first embodiment in that the concavo-convex pattern 13 is provided by using a plurality of rollers R in place of the plate-shaped die P in the pattern forming machine S. The other points are the same, and the same reference numerals are given to the same configurations and the description thereof is omitted. As shown in FIG. 4, the pattern forming machine S of the present embodiment is provided with four rollers R.
The peripheral surface of each of these rollers R is a pattern forming surface, and the protruding height of the pattern surface west of the forming surface gradually increases from the upstream side to the downstream side of the roller, Deep drawing is gradually performed. By using such a roller R, a deep uneven pattern can be formed on the gypsum board 10 without difficulty.
Moreover, since a plurality of rollers R are used as in the present embodiment, the following usage is also possible. By forming a different pattern on the molding surface of the roller R and selectively pressing or retracting the roller upward, the gypsum board 10 having a different pattern can be easily formed.

<Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition to the above, various modifications can be made without departing from the scope of the invention. (1) In the above-described first embodiment, the plate-shaped mold P, once pressed against the gypsum board 10, maintains this pressed state until the gypsum board 10 passes through the pattern forming machine S. The board 10 may be pressed a plurality of times during the process of passing through the pattern forming machine S.

(2) In the above embodiment, the concavo-convex pattern 13 may be preformed on the base paper 12 before the slurry is poured, and then the slurry may be poured.
In that case, the base paper 12 is required to have a high shape retention function.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a manufacturing process of a gypsum board according to a first embodiment.

[Fig. 2] Plan view of gypsum board

[Fig. 3] Sectional view of gypsum board

FIG. 4 is a schematic diagram of a manufacturing process of a gypsum board according to a second embodiment.

[Explanation of symbols]

10 ... Gypsum board 11 ... Gypsum core material 12 ... Board base paper 13 ... uneven pattern

Claims (3)

[Claims] 1. A gypsum board in which a slurry obtained by mixing calcined gypsum as a raw material for a gypsum core material with water is poured between base papers for forming the front and back surfaces of the gypsum board, formed into a predetermined shape, and then dried. The method for producing a gypsum board according to claim 1, wherein the gypsum board is embossed with a water content of 50% or less to give an uneven pattern to the gypsum board. 2. The method for producing a gypsum board according to claim 1, wherein the second embossing is performed in a state where the water content of the gypsum board is 50% or less. 3. The drying temperature is 100 after the embossing step.
The method for producing a gypsum board according to claim 1 or 2, which comprises drying at a temperature of not higher than ° C.