JPH10259357A - Adhesive composition for building board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive compsn. for building boards which has a good water resistance, does not allow mildew to grow, exhibits little shrinkage when dried, and has good applicability by compounding cement, gypsum plaster, a water-soluble paste, a thickener, and a filler which contains hydrated calcium silicate having a specified particles size as a part thereof. SOLUTION: This compsn. comprises 10-40 wt.% cement, 15-55 wt.% gypsum plaster, 25-65 wt.% filler, 0.2-1.0 wt.% water-soluble paste, and 0.2-0.6 wt.% thickener. The filler contains 5-30 wt.% hydrated calcium silicate (e.g. a grinding product of a calcium silicate heat-insulating material) having a particle size of 5-500 μm. Because of hydrated calcium silicate contained, the compsn. exhibits an increased thixotropy when mixed and kneaded with water and hardly exhibits sagging when heaped up on a wall substrate. When used, 100 pts.wt. powdery adhesive compsn. is mixed and kneaded with 40-50 pts.wt. water and heated up in spots on a wall substrate, and then a building board is pushed and stuck to the heaped compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition for a building board, and more particularly to a so-called direct bonding method in which a putty-like adhesive is interspersed on a base wall and the building board is pressed and adhered. The present invention relates to an improvement in an adhesive composition for building boards suitable for an adhesive used in a bonding method.

[0002]

2. Description of the Related Art Conventionally, plaster-based adhesives (for example, Japanese Patent Publication No. 61-14193) and cement-based adhesives (for example, Japanese Patent Publication No. 3-1184) have been known as this type of adhesive. I have. However, gypsum-based adhesives have a problem in water resistance, and have a problem that mold is easily generated in a humid environment. On the other hand, cement-based adhesives hang down more easily than plaster-based adhesives when they are scattered on the base wall, and are difficult to apply thickly. There is a problem in terms of workability that the use time is short, and further, there is a problem that drying shrinkage is large as compared with a gypsum-based adhesive, and a building board may peel off after construction.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional adhesive, and it is difficult for the adhesive to drip when it is mounted on a base wall. A main object of the present invention is to provide an adhesive composition for building boards which has good water resistance, has no mold, has good workability, and has small shrinkage due to drying.

[0004]

In order to achieve the above object, the adhesive composition for building boards of the present invention comprises a cement
40% by weight, gypsum plaster 15-55% by weight, filler 25-65% by weight, and a small amount of a water-soluble sizing agent and a thickener, and a part of the filler has a particle size of 5-500 μm. It is a hydrate, and its content is 5 to 30% by weight.

As the cement used in the present invention, an early-strength cement, an alumina cement or the like may be used in addition to the ordinary Portland cement. As plaster plaster, JIS-A
The use of gypsum plaster for boards as specified in 6904 is preferred.

[0006] In the present invention, the compounding amount of cement is 10
The reason why the amount of gypsum plaster is set to 15 to 55% by weight is that if the amount of cement is too large, the usable time is shortened, and if the amount of gypsum plaster is too large, the water resistance decreases. That's why.

In the adhesive composition for building boards of the present invention, calcium silicate hydrate having a particle size of 5 to 500 μm is used as a part of the filler. Examples of the above-mentioned calcium silicate hydrate include pulverized calcium silicate heat insulating materials such as grinding chips of calcium silicate heat insulating material. In addition, the calcium silicate heat insulating material referred to here includes, in addition to the calcium silicate heat insulating material specified in JIS-A9510, Japanese Patent Publication No. 57-495.
No. 07 etc. are also included. This increases the thixotropy when kneading by adding water, and makes it less likely to sag when served on the base wall.
The compounding amount is preferably 5 to 30% by weight. The reason why the use of the calcium silicate hydrate increases the thixotropic property is not yet well understood.

As fillers other than the calcium silicate hydrate, fly ash, silica sand, perlite, vermiculite, sepiolite, styrene beads and the like can be mentioned. In addition, a water-soluble glue such as polyvinyl alcohol is added in an amount of 0.2 to 1.0% by weight to obtain an initial adhesive strength,
Further, in order to increase the viscosity after adding water and kneading, it is preferable to add a thickener such as methyl cellulose in an amount of 0.2 to 0.6% by weight.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred adhesive compositions for building boards of the present invention include ordinary Portland cement 18% by weight, gypsum plaster 33.3% by weight, and fly ash 3
4.5% by weight, 3.1% by weight of perlite, 10.3% by weight of calcium silicate hydrate (grinding waste of calcium silicate material described in JP-B-57-49507), 0.6% by weight of polyvinyl alcohol, 0.2% by weight of methylcellulose
Is composed.

When the adhesive composition for building boards is used, 40 to 50 parts by weight of water is added to 100 parts by weight of the powdery adhesive composition and kneaded. And then press the building board and paste it.

[0011]

EXAMPLES Table 1 shows the results of the evaluation of the composition of one example of the present invention, and those obtained by adding and kneading 46 parts by weight of water to 100 parts by weight of the adhesive composition having the composition of the example. As a comparative example, Table 1 also shows the evaluation results of the conventional gypsum-based adhesive and the cement-based adhesive.

[0012]

[Table 1]

The meanings of the evaluation symbols shown in each column of "Workability", "Usable time", and "Adhesive strength (when absorbing water)" in Table 1 are shown below. Workability ◎: Does not sag, ○: Does not sag, but slightly shifts,
×: sagging, usable time ◎: usable after 30 minutes of kneading, ○: unusable after 30 minutes of kneading, usable after re-mixing, ×: unusable after 30 minutes of kneading,
Re kneading not the strength degree of adhesion (absorption of water) ◎: the adhesive itself or adhesive substrate disintegrating 2 kg / cm ² or more,
：: collapse of the adhesive itself or the adhesive substrate less than 2 kg / cm,
×: 1 kg / cm ² or less at the adhesion interface

The evaluation of the adhesives used as examples and comparative examples was performed by the following methods. (1) Workability: The kneaded adhesive is put on a concrete plate with a thickness of 30 mm or more, and the adhesive is checked for dripping. (2) Usable time The kneaded adhesive is packed into a 220 cm ³ cup, and the penetration is continuously measured using a penetrometer until 60 minutes after the start of kneading. When the penetration drops below 200, the working limit is reached. (3) Dry dimensional change rate: After filling the kneaded adhesive in a sheep-shaped type, wrapping it for 24 hours and curing it,
(5 ° C., RH 60%) for 7 days, and measure the dimensional change during this period. (4) Adhesive strength: The kneaded adhesive is adhered to a calcium silicate plate, left in a thermo-hygrostat (25 ° C., RH 60%) for 7 days, and then subjected to a tensile test. Further, in order to measure the adhesive strength at the time of absorbing water, a tensile test is performed after soaking for 24 hours.

From the results shown in Table 1, it was confirmed that the adhesive of the present invention had good workability, usable time, dry dimensional change, and adhesive strength.

[0016]

As described in detail above, according to the present invention, an adhesive composition for building boards having good water resistance, no mold, little shrinkage upon drying, and good workability can be obtained. Can be

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 18:08)

Claims (2)

[Claims] 1. A composition comprising 10 to 40% by weight of cement, 15 to 55% by weight of gypsum plaster, 25 to 65% by weight of a filler, and a small amount of a water-soluble glue or thickener, and a part of the filler. An adhesive composition for building boards, which is a calcium silicate hydrate having a particle size of 5 to 500 μm and a content of 5 to 30% by weight. 2. The adhesive composition for building boards according to claim 1, wherein the calcium silicate hydrate is a pulverized calcium silicate heat insulating material.