Method for preparing calcium carbonate from flame-retardant PVC (polyvinyl chloride) sheet material

Abstract

The invention discloses a method for preparing calcium carbonate from a flame-retardant PVC (polyvinyl chloride) sheet material. The method comprises the following steps: limestone is added into a pulverizer to be pulverized until the particle size is equal to or smaller than 0.25 mm, and calcium carbonate coarse powder is obtained; the calcium carbonate coarse powder is added into a grinder, thena compound surface treating agent consisting of hydrogenated castor oil isostearate and rapeseed oil fatty acid alkanolamide borate is added into the grinder to be ground to obtain calcium carbonatefine powder; and the calcium carbonate fine powder is transferred into a high speed mixer, and then a secondary modifier consisting of hexaphenoxy cyclotriphosphazene and polyaminopropyl methyl silsesquioxane is added into the high speed mixer to be mixed at a high speed uniformly, and drying is carried out to obtain the calcium carbonate for the PVC sheet material. The calcium carbonate obtainedby the invention is high in dispersibility, has high compatibility with PVC resin and wood powder, improves the interfacial adhesion of a PVC wood-plastic sheet material reaction system, improves themechanical properties of a composite material and the attractive appearance of an embellished product, is capable of endowing the PVC sheet material with relatively high processing properties, is relatively high in flame retardance and heat resistance, and can be widely used as an excellent PVC sheet material filler.

Description

technical field [0001] The invention belongs to the technical field of inorganic pigments, in particular to a method for preparing calcium carbonate for flame-retardant PVC boards. Background technique [0002] Calcium carbonate is an important inorganic chemical product, which is widely used in rubber, plastic, paper, paint, ink, medicine, automobile paint, cosmetics, food and other industries. However, due to the smaller the particle size of calcium carbonate particles and the more atoms on the surface, the higher the surface energy, the stronger the adsorption, and the mutual agglomeration between the particles; followed by calcium carbonate as an inorganic filler, the surface of the particles is hydrophilic and hydrophobic. Oil has poor affinity with organic polymers and is easy to form aggregates, resulting in internal defects of polymers and poor mechanical properties. In order to improve the filling performance of calcium carbonate, effective technology and surface m...

AI Technical Summary

Problems solved by technology

At present, most of the flame retardants in PVC sheets have strong polarity and poor compatibility with polymer bodies. When the amount added is small, the flame retardant effect cannot be achieved.

When these flame retardants are added in large amounts, it is easy to generate gaps with the matrix interface, which reduces the mechanical properties of wood-plastic panels.