JPH0615420B2 - Wet spray material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wet spray material containing no asbestos for forming a fire resistant coating on the surface of steel frames or partition walls of various structures. is there.

[Conventional technology]

As a wet spray material, a material using asbestos as a reinforcing fiber has been used for a long time, but as the use of asbestos becomes difficult, it is now considered to use inorganic fibers other than asbestos such as rock wool. It was Conventionally, as a typical example of a wet spray material for forming a refractory coating containing no asbestos, there is one described in Japanese Examined Patent Publication No. 54-29537, and its composition is as follows.

Rock wool 20-75% Hydraulic inorganic adhesive 25-60% Surfactant 0.1-1.0% Thickener 0.1-1.0% This wet spray material is air bubbles due to the action of the surfactant. Utilizing thickening by the action of entrainment and thickening agent, the mixture of fibrous material and adhesive is given the fluidity and adhesiveness required as a wet spray material, but its characteristics are the use of asbestos. It was not as good as the product, and the following problems remained.

Since the water retention is not sufficient, the sprayed product may come off before it solidifies, and it is not possible to spray thickly at one time.

Rockwool does not entangle fibers as much as asbestos, so the interlayer strength of the formed coating is weak.

There is no thixotropy, there is a tendency to become dull, and pumping using pipes is difficult.

[Problems to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems in a wet spray material that does not use asbestos, to enable a thick spray, to have good spray workability, and to obtain a wet spray material having excellent characteristics of a fire-resistant coating obtained. To provide.

[Means for solving problems]

The wet spray material provided by the present invention has a total solid content of 10 to 10
30% by weight of rock wool, 40-85% by weight of a hydraulic inorganic adhesive consisting of a mixture of Portland cement and gypsum, and 0.5-10% by weight of a mixture of fibrous hydrous magnesium silicate in a weight ratio. It is characterized by adding 0.8 to 1.5 times the amount of water and kneading to form a viscous paste.

The fibrous hydrous magnesium silicate, which is the most characteristic component of the wet spray material of the present invention, is a magnesium silicate clay mineral showing a fibrous morphology, and a preferable specific example thereof is sepiolite. (Mg ₄ ) [Si ₆ ] O ₁₅ (OH) ₂ (O
_{H 2) 2 · 4H 2 O} , palygorskite _{· (Mg 5) [Si 8} ]
_{O 20 (OH) 2 (OH} 2) , etc. ₄ · 4H ₂ O.

Although this fibrous hydrous magnesium silicate is fibrous, it does not have a long fiber shape that can be used as a fibrous reinforcing material like asbestos, but rather shows properties similar to talc. When this is blended in an appropriate amount into the above-mentioned wet spray material mainly composed of rock wool, the stability of the uniformly mixed state of all materials including water is increased, thereby significantly increasing the distance that can be pumped by a pipe and after spraying. It has the same physical properties as those using asbestos, such as allowing thick spraying without sagging or flaking, and also acts to improve the performance of the fire resistant coating formed from the sprayed material.

In the wet spray material of the present invention, it is not necessary to use any special component other than the fibrous hydrous magnesium silicate, but as the hydraulic inorganic adhesive, Portland cement and gypsum, preferably about 4: 1 to about 4: Used together in a weight ratio of 8.
By using a proper amount of Portland cement and gypsum in combination, the improvement of the construction performance by adding the fibrous hydrous magnesium silicate becomes particularly remarkable. Polyethylene oxide, methyl cellulose, sodium polyphosphate and the like can be used as the thickener, and alkylaryl sulfonic acid sodium soda and the like can be used as the surfactant, respectively.
When used in the following ratio with the main material, the combined effect of the fibrous hydrous magnesium silicate can be most remarkably brought out.

Rock wool 10 to 30% by weight Hydraulic inorganic adhesive 40 to 85% by weight Thickener 0.1 to 1.0% by weight Surfactant 0.02 to 1.0% by weight In the wet spray material of the present invention, Further, lightweight aggregate such as vermiculite may be blended as a filler up to about 30% by weight.

The wet spray material of the present invention is obtained by kneading the material mixture as described above with water in an amount of 0.8 to 1.5 times the weight ratio. The kneading procedure is not particularly limited, but usually, water is added to the above-mentioned material mixture and kneaded into a paste using a kneader such as a mortar mixer.

The wet spray material of the present invention can be sprayed onto a building steel frame, wall surface, etc. by an ordinary method using an arbitrary spray gun.

〔effect〕

Although the wet spray material of the present invention does not contain asbestos at all, it has completely different properties of rock wool fiber, powdery hydraulic inorganic adhesive, and water due to the unique action of fibrous hydrous magnesium silicate. The uniform mixing state of the three components is kept extremely stable even when pumped, and the fluidity is also stable at a high level, so it can be pumped directly to high places over 300 m, as with asbestos-blended products. And, of course, it has excellent horizontal pumpability. Also, it has excellent workability for spraying, and there is no fear of sagging or peeling.
Thick spray of 50 mm or more is possible in a single operation. Therefore, a coating having a thickness (30 to 50 mm) specified by the Minister of Construction for a steel frame fireproof coating can be formed once without the need for curing during spraying. Further, the fire-resistant coating formed by the wet spray material of the present invention is superior in the interlaminar strength, fire resistance, non-combustibility, etc. as compared with the similar wet spray material containing no fibrous hydrous magnesium silicate. In addition, it has the feature that shrinkage and cracking due to drying are small.

〔Example〕

 Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

Examples 1 and 2 Example 1 Example 2 Rockwool 30 20 Portland Cement 38.5 20 Gypsum 10 35 Sepiolite 5 5 Thickener 1 0.4 Surfactant (ABS) 0.5 0 Filler 15 19.6 Water 1.2 times 1.3 times as much as the above all materials Wet spray material having the above composition (numerical parts by weight) was prepared by the following procedure. First, a thickener, a surfactant, gypsum and Portland cement are mixed, then sepiolite is added and mixed by stirring, and rock wool and vermiculite are added and mixed. Water is added to the obtained mixture, and the mixture is stirred with a mortar mixer for about 2 minutes to form a paste.

Comparative Examples 1 to 4 Wet spray materials were prepared in the same manner as in Examples 1 and 2 except that some of the materials were changed as follows.

Table 1 summarizes the test results of physical properties and workability of each of the above examples.
It was shown to. The test method of the pressure feeding test is as follows.

Test method: Pour the material kneaded with a mixer into the hopper of the pump and pump it with the hose of the spray gun. At this time, the loss pressure is obtained from the readings of the pressure pump and the pressure gauge attached to the tip of the hose, and the flow resistance is calculated by the equation (1). Also, the pumping distance that should be less than or equal to the allowable pressure of the pumping machine is calculated by the equations (2) and (3).

Flow resistance Re [kgf ・ sec / cm ⁴ ] = ΔP / L ・ V …… (1) ΔP: Loss pressure [kgf / cm ² ] L: Pumping distance [cm] V: Average velocity in steady state [cm / s] Horizontal pumping distance Lh [cm] = ΔPh / Re · V (2) ΔPh: Horizontal pumping pressure [kgf / cm ² ] Vertical pumping distance Lv [cm] = ΔPv / (Re · V + γ)…
(3) Pv: Vertical pressure feed [kgf / cm ² ] γ: Unit volume weight of material [kg / cm ³ ]

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-56-120556 (JP, A) JP-A-61-295265 (JP, A) JP-A-58-41751 (JP, A) JP-B-54- 29537 (JP, B1) JP 60-13930 (JP, B2)

Claims (3)

[Claims] 1. A total of 10 to 30% by weight of rockwool based on total solid content, 40 to 85% by weight of a hydraulic inorganic adhesive consisting of a mixture of Portland cement and gypsum, and 0.5 to 10% by weight of fibrous material. A wet spray material for forming a refractory coating containing no asbestos, which is obtained by adding 0.8 to 1.5 times by weight of water to a mixture of hydrous magnesium silicate and kneading to form a viscous paste. 2. The wet spray material according to claim 1, wherein the fibrous hydrous magnesium silicate is sepiolite. 3. The wet spray material according to claim 1, which contains a thickener and a surfactant.