PVC raw material selection and formula


Ningbo Fangli Technology Co., Ltd. is a mechanical equipment manufacturer with nearly 30 years’ experiences of plastic pipe extrusion equipment, new environmental protection and new materials equipment. Since its establishment Fangli has been developed based on user’s demands. Through continuous improvement, independent R&D on the core technology and digestion & absorption of advanced technology and other means, we have developed PVC pipe extrusion line, PP-R pipe extrusion line, PE water supply / gas pipe extrusion line, which was recommended by the Chinese Ministry of Construction to replace imported products. We have gained the title of “First-class Brand in Zhejiang Province”.


PVC plastic is a multi-component plastic. Different additives can be added according to different uses. Due to different components, PVC products show different physical and mechanical properties, which can be applied in different occasions. PVC plastic pipe accounts for a large proportion in plastic pipe.


Today, let's talk about the knowledge of PVC raw material selection and formula in the production process of PVC pipes for reference.


SG-5 resin with low degree of polymerization shall be selected as the resin in hard pipe production. The higher the degree of polymerization, the better its physical and mechanical properties and heat resistance. However, the poor fluidity of the resin brings some difficulties to processing, so the viscosity is generally selected as (1.7 ~ 1.8) × SG-5 resin of 10-3pa • s is suitable.


Hard pipes generally use lead stabilizer with good thermal stability. Tribasic lead is commonly used, but its lubricity is poor. It is usually used together with lead and barium soaps with good lubricity.


When processing hard pipes, the selection and use of lubricants are very important. We should not only consider internal lubrication to reduce the intermolecular force and reduce the viscosity of the melt, which is conducive to molding, but also consider external lubrication to prevent the adhesion between the melt and the hot metal and make the surface of the products bright.


Metal soaps are generally used for internal lubrication and low melting point wax is used for external lubrication.


Calcium carbonate and barium (barite powder) are mainly used as fillers. Calcium carbonate can improve the surface performance of the pipe, and barium can improve the formability and make the pipe easy to set. Both of them can reduce the cost, but excessive dosage will affect the performance of the pipe. It is better to add no or less fillers to the pressure pipe and corrosion-resistant pipe.


If you need more information, Ningbo Fangli Technology Co., Ltd. welcomes you to call for a detailed inquiry, we will provide you with professional technical guidance or equipment procurement suggestions.

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