JPH0454706B2 - - Google Patents

Description

[Detailed description of the invention]

Conventionally, as shown in Japanese Patent Publication No. 50-24973, the wet spraying construction method for Rock Wool-based fireproof coating materials involves adding a water-curable inorganic binder such as Portland cement or gypsum to Rock Wool, and then applying an interfacial agent as a foaming agent. A water-soluble polymeric material is added as an activator or thickener, and this is kneaded with water to form an air-containing foam slurry, which is then pumped through a transport pipe and ejected from a nozzle along with compressed air to create lightweight fireproof insulation. Methods of spraying the coating layer are known. This wet spraying construction method sprays only a mixture of rock wool, cement, and asbestos through a nozzle.
At the same time, water is sprayed in the form of a mist from the fountain around the nozzle, and immediately after the dry mixture is sprayed from the nozzle, it is brought into contact with the water in the mist for the first time, and is sprayed onto walls, etc. Compared to the dry spraying method, dust is reduced. In addition to having almost no disadvantage of contaminating the working environment (pollution) due to scattering of particles, it also has the advantage of being able to be sprayed thickly in one go. However, the water-soluble polymer used as a thickener in the above wet spraying method has the following characteristics.
Performance is required. Easily soluble in water, the viscosity of the slurry can be freely adjusted by selecting the grade of added amount, and the generation of dust during spraying can be prevented.Water and rock wool do not separate during slurry transportation, and only water is ejected from the nozzle. The rock wool that is ejected from the nozzle does not remain in the transport pipe, and the surfactant added to the slurry stabilizes the bubbles generated, allowing each material to be transported as one with the coating material held in the bubbles. It has the ability to flow smoothly inside pipes without clogging, it improves the initial adhesion of the coating material after spray painting, and it does not sag even when the coating material is sprayed thickly.
To enable thick spraying with one spraying.However, water-soluble cellulose ethers such as methyl cellulose, polyethylene oxide, etc., which have been used for this type of purpose, each have their own merits and demerits, and meet the various requirements mentioned above. I can't be satisfied. For example, cellulose ethers have excellent viscosity and water retention properties, but they do not necessarily show satisfactory effects in meeting the above requirements, and polyethylene oxide usually tends to remain in a so-called sticky state in water and is extremely difficult to dissolve. Poor properties, thickening properties, water retention properties, air entrainment properties,
It has the disadvantage that it is less effective in terms of adhesion and the like. The inventors of the present invention have arrived at the present invention as a result of intensive research in order to solve the disadvantages of the conventional technology. Add water to 0.1 to 1.5 parts by weight of a water-soluble polymeric material prepared by blending non-ionic water-soluble cellulose ether and polyacrylamide or partially anionized polyacrylamide at a ratio of 90:10 to 40:60 (weight ratio) to make a slurry. The present invention relates to a rock wool-based coating material for spraying construction. According to the present invention, the following advantages (a) to (c) are provided. (a) Cellulose ether, polyacrylamide, and partially anionized polyacrylamide are all inexpensive, easily soluble in water, and the viscosity of the aqueous solution can be easily adjusted by adjusting the amount added and the clade. (b) Cellulose ether has excellent water retention, thickening properties, air entrainment properties, and adhesive properties, and polyacrylamide and partially anionized polyacrylamide have strong elasticity in aqueous solutions, and by using both together, rock wool spray coating can be achieved. Satisfies the above characteristics required for the material. (c) Partially anionized polyacrylamide can adjust the elastic force of the aqueous solution depending on the degree of anionization, and the selection of this degree of anionization,
By selecting the mixing ratio with cellulose ether,
Fluidity and sag prevention properties of rock wool spray coating materials can be adjusted. The rock wool used in the present invention can be produced from metallurgical slag or rock, and whatever the raw material, its main chemical components are 25 to 50% by weight SiO ₂ ,
3 to 20% Al ₂ O ₃ , 20 to 45% CaO and 3
to 18% MgO. Generally the diameter of individual fibers is 2 to 10 microns and the length is 2.54
cm, but the average length is 3.2 mm to 6.4 mm. 9.5 mm of synthetic mineral wool in the sprayed mixture
Preferably, it exists as a bundle with a length of 19.1 mm. Hydraulic inorganic adhesives include portland cement,
Early strength cement, ultra early strength cement, blast furnace cement,
Hydraulic cements such as fly ash cement and alumina cement, hemihydrate gypsum, anhydrous gypsum, lime plaster, dolomite, plaster clay, etc. can be used. Among the water-soluble polymers used in the present invention, cellulose ethers include methylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, etc., as long as they have a degree of ether substitution that is soluble in water. is also available. As polyacrylamide, those having a molecular weight of approximately tens of thousands to several millions are generally suitably used. In addition, so-called partially anionized polyacrylamide, which is partially anionized polyacrylamide with a saponifying agent such as sodium hydroxide, or a copolymer of sodium acrylate and acrylamide are also suitable for use because they impart particularly excellent elasticity to aqueous solutions. However, the degree of anionization in this case is −COO ⁻
It is desirable that the amount is 40 mol% or less. The blending ratio of cellulose ether and polyacrylamide or partially anionized polyacrylamide is determined by mixing the latter component with respect to cellulose ether.
The optimum condition is to mix within the range of 90:10 to 40:60 (weight ratio), and if the content of polyacrylamide or partially anionized polyacrylamide is less than the lower limit of 10%, the elasticity of acrylamide will be poor and the thickness will be reduced. If the upper limit of 60% is exceeded, the water retention property of cellulose ether becomes impossible.
Foaming, stability effects are less likely to occur, and the flow of the coating material in the transport pipe is extremely poor. Next, talking about the blending ratio of various materials in this invention, the main material, rock wool, is 20 to 75% by weight.
(hereinafter simply written as %), hydraulic inorganic adhesive
The range is 25-80% and the water-soluble polymer substance is 0.1-1.5%. When the Rock wool content is less than 20% and when the binder content is greater than 80%, the specific gravity of the coating layer increases, and walls, pillars, etc. must be made stronger accordingly. The weight of the entire object increases. If Rockwool is 75% or more, it will be too light and the flow in the transport pipe will be poor, and the thickness at the time of spraying will be small, making thick spraying, which is an advantage of using the coating material of this invention, impossible, and it is also fireproof. reduce sex. When the hydraulic inorganic adhesive content is less than 25%, the strength of the spray-formed coating layer is lost. In particular, if the water-soluble polymer thickener is less than 0.1%, the effect of adding it will not be apparent, and if the thickener is more than 1.5%, the effect will not be increased and the cost will only increase. In the present invention, as a foaming agent, an anionic surfactant such as sodium dodecylbenzenesulfonate, a condensation product of an alkylphenol and ethylene oxide, and an anhydrous condensation product of a long-chain aliphatic alcohol and ethylene oxide are used as necessary. It is also possible to use a surfactant such as a surfactant. Furthermore, in this invention, up to about 5% asbestos can be used as a partial substitute for rock wool, which is the main material, in order to improve water retention and increase adhesion to the surface to be worked. Next, a specific example will be given. Example A rock wool spray coating material (slurry form) having the formulation shown in Table 1 was spray coated onto a vertically erected mortar base, coated thickly until sagging occurred, and the thickness was measured. We also investigated whether the viscosity of the slurry after preparation of the coating material developed quickly or slowly. Furthermore, after preparing the coating material, the slurry is 5cm in diameter and 50cm in length.
The fluidity was evaluated based on the time required for the entire amount to flow out. At that time, those that flowed out within 5 minutes were marked as ○, and those that took more than 5 minutes were marked as ×. The results were as shown in the same table. The partially anionized polyacrylamide shown in Table 1 had an anionization degree of 30 mol%.

【table】

[Table] In each of the examples according to the present invention, the slurry viscosity was easily developed, and the thickness that could be sprayed could be increased without causing sag after spray coating.

Claims (1)

[Claims] 1 100 parts by weight of a mixture of 20 to 75% by weight of Rock wool and 80 to 25% by weight of a hydraulic inorganic adhesive, and a mixture of nonionic water-soluble cellulose ether and polyacrylamide or partially anionized polyacrylamide in a ratio of 90:10 to 40:60. A rock wool coating material for spraying construction that is made into a slurry by adding water to 0.1 to 1.5 parts by weight of a water-soluble polymeric substance (weight ratio).