Surface treatment method of nano-calcium carbonate used for polyvinyl chloride plastisol

Abstract

The invention discloses a surface treatment method of nano-calcium carbonate used for polyvinyl chloride plastisol. The surface treatment method comprises the following steps: adding nano-calcium carbonate serous fluid into a reaction kettle, wherein the specific surface area (BET) of nano-calcium carbonate in the serous fluid is 18.0-60.0m<2> / g and the pH of the nano-calcium carbonate serous fluid is 8.5-9.5; heating to 70-95 DEG C, stirring, adding a mixed modifier accounting for 1.8-6.0% of the mass of the nano-calcium carbonate in the serous fluid, continuing stirring for 30-180 minutes, thus completing surface treatment. The mixed modifier is a mixture of stearic acid alkali metal saponified matter and calcium stearate, the mass ratio of fatty acid to calcium stearate in the complex modifier is 20-70%, and the proportion of the using quantity of the fatty acid to a saponifier is 1: 1. According to the method, the fatty acid is saponified by a strong base, so that the shortcoming that the fatty acid is difficult to react with the surface of calcium carbonate in water to generate the calcium stearate during wet process surface modification of the nano-calcium carbonate can be overcome; and the calcium stearate is directly introduced through fatty acid saponification liquor, so that a significant surface modification effect is obtained. The method has the advantages that raw materials are low in price and easy to obtain, the processes are simple and feasible, and the quality of a product is state. The method has significant economic benefits and social benefits.

Description

Technical field: [0001] The invention relates to a preparation method of a paint additive, in particular to a surface treatment method of nano calcium carbonate for polyvinyl chloride plastisol. technical background: [0002] After surface treatment, nano-calcium carbonate can be used as filler and rheological additive in paint, ink and other industries due to its small particle size, good surface performance and dispersibility, and can endow the medium with certain thixotropy and yield stress. [0003] Nano-calcium carbonate is an important component in the formulation of PVC plastisol. Adding nano-calcium carbonate to the PVC paste of automobile primer can not only increase its wear resistance and stone chip resistance, but also facilitate the adjustment of rheological properties, making it It has a certain thixotropy, which meets the needs of spraying and other processing processes, that is, low viscosity under high shear, high viscosity under low shear, and also has cert...

AI Technical Summary

Problems solved by technology

[0013] Aiming at the characteristics of PVC plastisol, Chinese invention patent CN 200710124944 discloses a surface treatment method of nano-calcium carbonate using carboxyl-terminated polyamide resin as a modifier, and has achieved some remarkable effects, but carboxyl-terminated polyamide resin is a A macromolecular compound, which is not easy to disperse in the nano-calcium carbonate slurry, which will lead to the disadvantage that the nano-calcium carbonate / PVC plastisol system is not stable

Chinese invention patents report a method of composite surface treatment of polyester dispersant and fatty acid (or sodium salt) on nano-calcium carbonate, but polyester dispersant has the disadvantage of being easy to hydrolyze, which causes PVC plastisol to solidify and form an unstable film potential threat of