JPH0132065B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a gypsum board with a laminate bonded to it, which uses a resin impregnated into a gypsum board base paper to increase the adhesive strength of the gypsum board. For ceiling panels made of gypsum board, etc.
For long products with a length of 90 cm or more, a piece of wood made of less warped wood such as zielton or plywood is usually attached to the length and width of the gypsum board. The reason for pasting the above-mentioned beams is to reduce the amount of deflection of the gypsum board and improve workability, and also because it is used to fix the ceiling board to the ceiling joists or verge using various nails when installing the ceiling board. It is. The manufacturing method for this type of plasterboard is generally assembling the boards using a board assembly machine and applying adhesive using a roll coater.
After applying approximately 180gr/m ² to 250gr/m ² , this sand is pasted on a plasterboard and pressed using a press machine.
It is manufactured under pressure of ~3Kg/ ^m2 . The adhesive used in this case is generally an emulsion type adhesive such as vinyl acetate emulsion, ethylene vinyl acetate emulsion, maleic anhydride emulsion, or urea acetate emulsion. Here, the gypsum board is a molded board having a core of gypsum and covered with base paper for gypsum board on both sides and longitudinal sides of the gypsum board. In general, base paper for plasterboard consists of several layers of base paper, with the inner layer 1 to 3 in contact with the plaster.
The layer is made porous so that the gypsum core and base paper adhere sufficiently, and the acicular crystals of the gypsum can easily penetrate into the layer. On the other hand, the surface side to which the sandpaper is attached is sized and densely made to increase surface strength, so it is more water resistant than the surface, for example, it absorbs one drop of water. It takes about 1 hour. For this reason, the emulsion type adhesive applied to the surface of the base paper does not penetrate into the base paper for board, and the slats are in a state of adhering to the surface layer of the base paper for board. Therefore, when conducting an adhesive strength test between gypsum board and gypsum board, almost all of the adhesive peels off from the space between the base paper for board, and the adhesive strength is determined by the strength between the base paper for board. Normally, the strength between the sheets is 1.3 to 2.1 Kg/cm ² , and at present, the strength between the sheets cannot be increased any further, and therefore the adhesive strength of the shingles cannot be maintained sufficiently, leading to the problem that the shingles peel off during construction. In addition, since moist, warm air flows through the gaps in the joints of the ceiling boards, dew condenses on the board surface in the winter and on the surface of the boards in the vicinity, resulting in a significant drop in adhesive strength of approximately 50% compared to when it is air-dried. do. As described above, the laminate of the conventional gypsum board with gypsum board is adhered only to the surface layer of the gypsum board base paper, so it was not possible to obtain an adhesive strength higher than the interpaper strength. The adhesive strength is increased by bonding the wood through a resin that is impregnated from the surface layer of the base paper to the plaster part.
Its composition consists of applying a solution prepared by dissolving an isocyanate prepolymer containing unreacted isocyanate in an organic solvent to the plasterboard area to impregnate it, and then immediately applying a water-containing adhesive to the plasterboard. is attached to the adhesive part, and the prepolymer is turned into a resin by the water content of the adhesive and then attached. The present invention will be described in detail above along with examples. The isocyanate prepolymer containing unreacted isocyanate in the present invention is an isocyanate polymer whose polymerization reaction has been stopped at an intermediate stage, and preferably has a viscosity of 100 to 200 cps/25°C.
Then, the isocyanate prepolymer is diluted with a solvent such as methyl ethyl ketone, xylol, trol, etc. to a viscosity of 20 cps/25°C, preferably
It is recommended to use a dissolving solution with improved permeability at 5 cps/25°C or less. The solution is applied to a gypsum board at a rate of 50 to 100 gr/m ² using a roll coater, and then immediately a laminate coated with a water-containing adhesive is adhered. Here, the water-containing adhesive is an adhesive that contains water absorbed by the prepolymer, and may be, for example, a conventional emulsion type adhesive. When a piece of wood coated with the adhesive is attached to a piece of sand coated with the above solution, the isocyanate prepolymer impregnated from the surface of the board base paper to 1 to 2 mm of the gypsum layer reacts with the moisture in the adhesive, causing the resin to become The beam is bonded to the resin. Here, since the beam is directly bonded to the gypsum layer via the resin, the bonding strength does not depend on the interpaper strength of the board base paper, and extremely high bonding strength can be achieved. In addition, since the polyisocyanate resin acts as a waterproof membrane, the adhesive strength of the present invention is
It has superior properties and is stronger than the air-dry adhesive bonded using only conventional emulsion type adhesives. Next, Examples and Comparative Examples of the present invention will be shown. Example 1 A plaster board according to the present invention was manufactured under the following conditions, and its adhesive strength was measured. The measurement results are shown in Table 1. Adhesion conditions: 300 parts of methyl ethyl ketone was mixed with 100 parts of isocyanate prepolymer (containing 30% unreacted isocyanate, viscosity 150 cps/25°C). The viscosity at that time was 2 cps/25°C. This was applied to plasterboard at 65 gr/m ² using a roll coater, and wood was bonded under the same conditions as in Comparative Example 1.

[Table] Comparative Example 1 A wood-covered gypsum board ceiling board was manufactured by a normal manufacturing method under the following conditions, and its adhesive strength was measured. The measurement results are shown in Table 2. Adhesion conditions (1) Adhesive vinyl acetate emulsion (solid content 49%) (2) Application amount 220gr/m ² (3) Pressure force 2.5-3.0Kgf/cm ² (4) Pressure time 20 minutes (5) Wood Zielton

[Table] As is clear from the above-mentioned Example 1 and Comparative Example 1, the adhesive strength of the gypsum board material according to the present invention is more than twice that of the conventional slat adhesive strength in an air-dried state.
It can be seen that it has more than three times the strength under dew condensation.

Claims (1)

[Claims] 1. A solution obtained by dissolving an isocyanate prepolymer containing unreacted isocyanate in an organic solvent is applied to the plaster board area to impregnate it,
A method for manufacturing a gypsum board with a laminate bonded to it, characterized in that immediately afterward, laminate coated with a water-containing adhesive is affixed to the laminate attachment portion, and the prepolymer is converted into a resin by the water content of the adhesive and then adhered. .