JPH023779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When polyisocyanate encounters moisture or water, it undergoes a chemical polymerization reaction to produce carbon dioxide and has the property of curing with strong adhesive strength. This reaction is even more strongly promoted in the presence of an alkali. When water is added to cement, it becomes strongly alkaline, but when polyisocyanate reacts with moisture and water and polymerizes, the coexistence of alkali accelerates the reaction, so the combination of the three components of polyisocyanate, cement, and water is called polyisocyanate. This is the optimal method for obtaining a polymerized cured product in a short time. The reaction between polyisocyanate and water is extremely complex, and when one reaction occurs, other reactions proceed one after another in a chain fashion to reach the final compound. An example of such a reaction is as follows. In the first place, cement can ultimately be used as a cured product with high rigidity, but it cures slowly and has low adhesive strength. However, by combining it with polyisocyanate, high strength can be obtained in a short period of time, so the waiting time can be shortened, and after that, the rigidity due to hardening of the cement allows for practical use. On the other hand, polyisocyanate immediately reacts with water and cures, and although it has strong adhesive strength, it has low rigidity and foams, so that a dense cured product cannot be obtained. A high-quality cured product can be obtained in a short time only by mixing polyisocyanate, cement, and water together. To explain further, carbon dioxide produced by the reaction between polyisocyanate and water reacts with alkaline earth metal oxides in cement in the presence of water to form carbonates, which is a phenomenon. No foaming occurs. The use of the cured product produced in this way has a wide range of applications, and provides many social benefits such as shortening the construction period, improving the working environment, and saving materials. One effective example of its use is that the presence of moisture on the adhesive surface, which was a drawback of conventional materials, no longer becomes a problem.
Work conditions at concrete construction sites can be significantly improved. It has many other benefits, such as pouring concrete onto wet surfaces, spraying mortar, and accelerating hardening during emergency construction.
However, polyisocyanates are generally highly viscous liquids, and their addition and dispersion are extremely difficult and almost impossible due to their rapid reaction. The amount of polyisocyanate added is 3% to 15% to the cement, and 1% to 5% to the total amount when made into mortar, so polyisocyanate, which is a highly viscous liquid, can be uniformly added within the pot life. cannot be dispersed into If polyisocyanates could be made into powder, all of these problems could be solved. The present invention is directed to a method to meet these needs. Moreover, if the powdered polyisocyanate is stored in a moisture-proof manner, its effectiveness will be maintained for a long period of time. In order to adsorb, impregnate, and coat polyisocyanate on porous material in an extremely dry state, the amount of adsorption varies depending on the nature of the porous material, so find out the approximate amount of adsorption through experiments and adjust the viscosity to match that amount. It can be obtained by mixing polyisocyanate solutions with varying amounts of solvent in the same manner, stirring thoroughly, and then volatilizing the solvent. As an example, 1000 g of amorphous silica with a particle size of 0.05 μm was mixed and stirred into a solution made by adding 600 g of toluene to 1000 g of polyisocyanate to make it low in viscosity, and the resulting toluene-rich wet body was heated while stirring. When toluene was volatilized, polyisocyanate powder was obtained, and the yield was approximately 100% of the theoretical yield. This powder is completely dry and is extremely easy to handle. The bending strength and compressive strength after hardening of 1:2 mortar containing powdered polyisocyanate according to the present invention at a ratio of 3% to cement are shown in Table-
1, and its performance is improved compared to plain concrete. In this way, even when powdered polyisocyanate is added to cement in small amounts, it can be easily added without considering the carrier, and since it is the same powder, it can be uniformly dispersed, and shortening the curing time can shorten the construction period and can also be used for emergency construction. It is an invention that brings social benefits, such as helping to reduce overall costs. 【table】

Claims (1)

[Claims] 1. A solution in which a urethane prepolymer (hereinafter referred to as polyisocyanate) is dissolved and dispersed in an aromatic solvent such as toluene or xylene, a linear solvent such as ethyl acetate or butyl acetate, a fluorocarbon solvent, or a mixed solvent thereof. In natural minerals such as pumice, the volatile matter and bound water inside are scattered due to intense heat such as eruptions, leaving behind voids, or natural ores are fired at high temperatures and then chemically treated. Among compounds, amorphous substances or those that have been dried and pulverized to increase interparticle adsorption (hereinafter referred to as
A method for producing powdered polyisocyanate obtained by adding a porous material (called a porous material), mixing and stirring to adsorb, impregnate, and coat the polyisocyanate onto the porous material, and then removing the solvent by heating.