Preparation method of special low-viscosity activated calcium carbonate for silicone adhesive

Abstract

The invention discloses a preparation method of special low-viscosity activated calcium carbonate for silicone adhesive. The preparation method comprises the following main steps: cane sugar being 0.3-0.8% of calcium hydroxide by weight is added in calcium hydroxide slurry; then kiln gas is introduced for quickly carbonizing; the initial temperature of the carbonization is controlled about 30 DEG C, and the final temperature is controlled about 55 DEG C; after the carbonization is finished, zinc chloride being 0.5-10% of calcium carbonate by weight is added in the slurry; the calcium carbonate slurry is grinded by adopting a vertical bead mill. Mixed emulsion of lauric acid and stearic acid is added in the grinded slurry; under the effect of a homogenizing pump, the dispersion of calcium carbonate and the surface coating are synchronously finished. Finally, the product is obtained by filtering and drying. The particle size of the product is within 0.3-0.8 microns; no agglomeration phenomenon is generated; the activation degree is higher than 99%; the oil absorption value is about 17 g / 100 g CaCO3. The viscosity of simulated pasty size is about 75,000 mPa.S; the simulated pasty size can be used as special low-viscosity functional filler for the silicone adhesive.

Description

technical field [0001] The invention relates to a preparation method of active calcium carbonate, in particular to a preparation method of low-viscosity active calcium carbonate specially used for silicone rubber. technical background [0002] Silicone structural sealant, commonly known as silicone structural adhesive in the construction and decoration industry, is an important part of room temperature curing (RTV) silicone rubber, which can be cured into an elastomer at room temperature without heating, light or other special conditions , very convenient to use; silicone structural sealant has remarkable characteristics such as high and low temperature resistance, weather aging resistance and ozone resistance, and also has the characteristics of good adhesion to various substrates and strong displacement resistance, so it has become a hidden frame curtain wall The key and only structural bonding sealing material; the main component of silicone structural adhesive is hydroxy...

AI Technical Summary

Problems solved by technology

[0002] Silicone structural sealant, commonly known as silicone structural adhesive in the construction and decoration industry, is an important part of room temperature curing (RTV) silicone rubber, which can be cured into an elastomer at room temperature without heating, light or other special conditions , very convenient to use; silicone structural sealant has remarkable characteristics such as high and low temperature resistance, weather aging resistance and ozone resistance, and also has the characteristics of good adhesion to various substrates and strong displacement resistance, so it has become a hidden frame curtain wall The key and only structural bonding sealing material; the main component of silicone structural adhesive is hydroxyl silicone oil (methyltrimethoxysilane), which affects the bonding strength of silicone structural adhesive depends on the chemical composition, formula, The type and amount of reinforcing agent, etc.; ultra-fine calcium carbonate particles are used as a reinforcing agent for silicone rubber due to their unique characteristics, which greatly improves the tensile strength, modulus and hardness of the rubber; ultra-fine ground calcium carbonate The oil absorption value is low, and the viscosity of the made glue is small, which is convenient for construction, but the silicone glue made has poor toughness and low tensile strength; while nano-active calcium carbonate greatly improves the toughness and tensile strength of silicone glue, However, due to the fine particles and large specific surface area, the viscosity of the glue is high, which is not conducive to construction.