JPH02311379A - Refractory coating material - Google Patents

Abstract

PURPOSE:To uniform spray, to improve adhesivity and to suppress reduction in bond strength after hardening and drying by forming a refractory coating material from specific amounts of a parent material comprising a cement, light- weight aggregate and an endothermic material in a specific ratio, and further a water-soluble resin and a synthetic resin-based admixture. CONSTITUTION:A parent material comprising 2.5 to 20wt.% cement, 5 to 30wt.% light-weight aggregate and 50 to 92.5wt.% endothermic material is blended with 0.1 to 1.0wt.% water-soluble resin and 1 to 10wt.% synthetic resin-based admixture based on the amount of parent material. Since this refractory coating material has an extremely small amount of cement blended, cracking caused by shrinkage after drying and hardening will not occur. The amount of the light-weight aggregate and the endothermic material blended, especially the amount of the endothermic material blended can be enlarged by addition of the water-soluble resin and the synthetic resin admixture and the refractory coating material has excellent fire resistant properties, improved adhesivity to sprayed surface and excellent bond strength after hardening.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fireproof coating material for construction, particularly a fireproof coating material that is sprayed on the surface of a steel structure as a cross-wire material and cured.

[Conventional technology] Asbestos, rock wool, vermiculite, etc. have been used as fire-resistant coating materials, but each has had problems with pollution, appearance, weather resistance, etc. .

JP-A-61-77687 discloses a fire-resistant composition containing hydraulic cement, lightweight aggregate, and a substance with a high degree of hydration, which can be mixed with water and sprayed as a fire-resistant coating. used.

[Problems to be Solved by the Invention] However, when the above-mentioned fireproof coating material containing the hydraulic cement is sprayed onto a base material, the spraying tends to cause unevenness on the surface and the thickness is uneven. However, the adhesion was not always sufficient, and spraying had the problem that the adhesive strength of the coating layer decreased due to drying shrinkage after curing.

The purpose of the present invention is to achieve uniform spraying and excellent adhesion, and
It is an object of the present invention to provide a fireproof coating material that exhibits little decrease in adhesive strength after curing and drying.

[Means for Solving the Problems] The present inventors have found that the shrinkage after drying of spraying is due to the drying shrinkage of hydraulic cement, and by using a binder to replace it, the adhesion can be improved. We were able to obtain a fire-resistant coating material with high adhesive strength and excellent adhesive strength.

That is, the present invention provides a base material consisting of 2.5 to 20% by weight of cement, 5 to 30% by weight of lightweight aggregate, and 50 to 92.5% by weight of endothermic material, and a water-soluble resin of 0.1% to the base material. -1
．． 0% by weight and 1-10% by weight of a synthetic resin admixture.

fil Cement Ordinary, early-strength and other Portland cements, hydraulic cements such as alumina cement, and various mixed cements are used, but ordinary Portland cement is usually used.

The blending amount of cement as a base material is 2.5 to 20% by weight,
Preferably it is 5 to 15% by weight. If the proportion of cement is less than 2.5% by weight, the ratio of cement to the entire material will be small, the function as a binder will be insufficient, and the mechanical strength of the hardened coating layer will be insufficient. On the other hand, when the blend exceeds 20% by weight, the adhesive strength of the cement itself increases and the adhesive strength after curing is sufficient, but as a result of the increased specific gravity of the kneaded material when used for coating, it causes problems when blowing (-1). resulting in a decrease in blowing thickness,
Work efficiency decreases when the vertical pumping distance is reduced during pumping. In addition, in the case of spraying, the cement shrinks significantly during dry hardening afterward, and cracks are likely to occur in the coating layer.

(2) Lightweight Aggregates Lightweight aggregates that are usually mixed with cement include, for example, expanded perlite, expanded vermiculite, expanded shale, pumice, and shirasu balloons. These may be used in combination. Among them, expanded vermiculite has good scattering properties when sprayed with a mixed material, and is preferably used alone or as a mixture with expanded perlite.

The amount of lightweight aggregate is 5 to 30% by weight, preferably 10 to 25% by weight in the base material. If the composition is less than the above range, the specific gravity of the hardened coating layer will increase, and the amount of coating material used per unit area will increase in order to obtain the same fire resistance performance. Furthermore, the adhesion after spraying also decreases. If the content exceeds 30% by weight, the mechanical strength of the cured coating layer will decrease, and the adhesion and fire resistance will also decrease.

(3) Endothermic substance The endothermic substance used in the present invention is a substance that decomposes or dehydrates when heated and consumes the added heat, and solid inorganic water-containing compounds such as hydrates and hydroxides are used. Examples of such substances include aluminum hydroxide, aluminum hydroxide hydrates such as gibbsite, boehmite, and diaspore, zeolite minerals such as chabazite and mordenite, allophane, halloysite, and unexpanded vermiculite. Hydrous silicates of aluminum, such as hydrated silicates of aluminum, hydrated silicates of magnesium, such as acpulgite, and hydrated sulfates, such as ettringite. Among them, aluminum hydroxide is preferably used.

Since the endothermic substance greatly affects the fire resistance of the coating layer, the larger the amount added, the more effective it is. However, mixing too much will relatively reduce the mixing ratio of cement.

The content of endothermic material in the present invention ranges from 50 to 92.5% by weight, preferably from 60 to 85% by weight.

The required fire resistance cannot be obtained with the ungrooved content of 50% by weight.
If the content exceeds 92.5% by weight, the mechanical strength and adhesion of the coating layer will decrease because the proportion of cement will be small.

(4) Water-soluble resin The fireproof coating material of the present invention does not have enough viscosity to adhere uniformly to a surface, especially a steel surface, when spraying with only the above-mentioned base material composition. The water-soluble resin gives appropriate viscosity to the fresh mixture of coating materials kneaded with water, and has the effect of uniformly spraying it on the surface and adhering it to the entire surface, as well as improving the water retention of the mixture of coating materials. This improves the workability of spraying by preventing material separation of mixed materials. It also prevents cracks after the coating layer has hardened,
Improve the properties of the coating hardening layer.

Examples of such water-soluble resins include methyl cellulose and polyvinyl alcohol.

The content of the water-soluble resin in the fireproof coating material of the present invention is 0.1 to 1.0% by weight, preferably 0.15 to 0.5% by weight, based on the base material consisting of the cement, lightweight aggregate, and endothermic substance. %. If the amount added is less than 0.1% by weight, no effect of addition is observed and the adhesion of the kneaded product is poor. If it is added in excess of 1.0% by weight, the viscosity becomes too high and the workability of spraying decreases. The amount of spraying is reduced, and
As a result of the dispersion of the base material due to the surfactant effect of the water-soluble resin, the mechanical strength of the coating layer after drying and curing decreases.

(5) Synthetic resin admixture The synthetic resin admixture used in the present invention is generally a fine particle synthetic resin dispersion that forms a suspended dispersion state in water, and has an average particle diameter of 0.05 to 0.

l1m, preferably 01-70pm solid powder or emulsion or latex. If this admixture is a powder, it can be mixed in advance with the base material, but in the case of latex or emulsion, it is added and mixed during the preparation of the kneaded material for work.

This synthetic resin admixture increases the strength of the cured product when the sprayed coating material dries and hardens, and also increases the adhesion of the cured product to the surface when sprayed.

Resins used in such admixtures include acrylic polymers, acrylic-styrene copolymers, ethylene-vinyl acetate copolymers (EVA), styrene-butadiene copolymer rubber (fsBRl), ethylene-vinyl acetate-vinyl Examples include persatate fVeoVA) copolymer, vinyl acetate/vinyl persatate copolymer fVAVeoVA), and the like. Among them, ethylene/vinyl acetate copolymer (EVAI) can be preferably used.

The amount of these synthetic resin admixtures added is 1 to 10% by weight, preferably 1 to 5% by weight based on the base material composition. If the amount added is less than 1% by weight, the effect of the addition will be small, and the resulting cured coating will easily peel off from the surface when sprayed, and if it is added in excess of 10% by weight, the effect of further improving adhesion will be small, and on the contrary, Fire resistance performance may deteriorate.

(6) Spraying is performed by adding 50 to 70 parts of water to 100 parts by weight of the coating material of the present invention. When the synthetic polymer additive described in Section 2 is an aqueous emulsion, it is blended in consideration of its water content.

The obtained mixed material is sprayed onto architectural steel beams and columns to a required thickness using a mortar pump and a mortar spraying machine. Depending on the case, it may be applied by troweling, and in that case, the mixed water content is adjusted to give a kneaded material with a consistency suitable for troweling.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples. In the following Examples and Comparative Examples, unless otherwise specified, parts and percentages are based on weight.

Example 1 Cement: White cement (manufactured by Nippon Cement ■)
10 parts Lightweight aggregate: 1:1 part by weight mixture of expanded pearlite (manufactured by Azatubalite ■) and vermiculite (manufactured by Nippon Fireproof ■) 20 parts Endothermic substance Aluminum hydroxide (manufactured by Nippon Light Metal ■) 70 parts
After thoroughly mixing with a mortar mixer, 60 parts of water and 0.2 parts of water-soluble resin: Hl Metrose 90SH15000 (manufactured by Shin-Etsu Chemical Co., Ltd., methylcellulose), admixture: Movinyl Powder E-40 (Hoechst Gosei Co., Ltd.) 2.0 parts of EVAI (manufactured by E.I.) were added and kneaded.

Various performances of the obtained interfering material were evaluated as follows.

fa) Adhesion status Use a mortar pump and spray machine to spray the kneaded material onto a transparent plastic surface held upright, and immediately visually observe the adhesion of the kneaded product from the opposite side. evaluated.

○・There are no air bubbles on the adhesion surface, and the adhesion is uniform.

△Although it adheres uniformly, bubbles are noticeable on the adhered surface.

×: There are coarse air bubbles on the adhesion surface, and it is only partially adhered.

fb) Adhesive strength kgf/cm21 The adhesive was sprayed onto a building steel frame in the same manner as above, and then left to harden for 4 weeks. The thickness of the cured film was 30 mm. Make a cut into the cured body with a knife to a side length of 40 x 40 mm until it reaches the steel frame. Glue the attachment to the surface with epoxy adhesive and pull it using a spring scale, so that the cured body becomes the steel frame. The scale of the spring scale was read at the time when it was peeled off from the surface, and the adhesive strength was determined to be kgf/cm21.

(c) Compressive strength (kgf/cm2) Compliant with JIS A3201.

(d) Fire resistance and dry specific gravity After molding and hardening a 70 mm square cube, measuring its specific gravity, and then installing a thermocouple in the center, the molded body was heated to 1000°C. The molded product was placed in a furnace, and the time (minutes) until the center temperature of the molded product reached 350° C. was measured, and the degree of flame performance was determined based on the time.

(e) Amount of drying shrinkage Compliant with JIS A1129.

The evaluation results based on the above are shown in Table 1.

Comparative Example 1-11 Using the same materials as in Example 1, evaluation was made in the same manner as in Example 1 with the formulations shown in Table 1. The evaluation results are shown in Table 1.

[Effects of the Invention] The fireproof coating material of the present invention contains much less cement than conventional cement-based fireproof coating materials, so there is no cracking due to shrinkage after drying and hardening, and it is compatible with water-soluble resins and synthetic resins. By adding admixtures, it is possible to increase the amount of lightweight aggregate and endothermic substances, especially the amount of endothermic substances, which has excellent fire resistance, and has good adhesion to surfaces when sprayed, and hardening. The adhesive strength afterwards is also excellent.

Claims (1)

[Claims] (1) Cement 2.5-20% by weight, lightweight aggregate 5-30%
0.1-1.0% by weight of a water-soluble resin and 1-10% by weight of a synthetic resin admixture are added to a base material consisting of 50-92.5% by weight of an endothermic substance and an endothermic substance. A fire-resistant covering material characterized by: