Production process and performance characteristics of modified PVC polyvinyl chloride granulation processing

The granulation process is the production process of producing granular plastic from high polymer resin and various additives and additives, which are measured, clubbed, plasticized, and cut into particles. Plastic particles are semi-finished products in the plastic molding and processing industry, and are also raw materials for extrusion, injection molding, hollow blow molding, foaming, and other molding processes.

Extrusion granulation is the most basic and simple granulation method, widely used. Extrusion granulation can be achieved using single screw and twin screw extruders. Mainly control the extrusion temperature, screw speed, cutter speed, and particle cooling. Make the granular material not sticky, with uniform particle size and good plasticization. Adjust the cutting speed to a particle length of 3-4 mm. Adjust the screw speed to ensure that the particles do not adhere.

Modified PVC performance characteristics

Modified PVC--polyvinyl chloride PVC resin generally refers to an amorphous polymer homopolymerized by vinyl chloride monomer, referred to as PVC. PVC has high chemical stability and can withstand any concentration of hydrochloric acid, less than 90% sulfuric acid, 50%-60% nitric acid and less than 20% caustic soda solution at room temperature. PVC resin is insoluble in water, gasoline, alcohol and vinyl chloride, and low molecular weight can be soluble in ketones and other ketones, lipids or chlorinated hydrocarbon solvents.

Polyvinyl chloride (PVC) has no obvious melting point. It appears in a glassy state below 85 ℃ and begins to soften at 80-85 ℃. It appears in a viscoelastic state at 85-175 ℃ and turns into a leather like state when heated above 130 ℃. It is in a seed melting state at 175-190 ℃ and a soft flowing state at 190-200 ℃. It begins to flow at 180 ℃ and under pressure at 145 ℃. The glass transition temperature is above 8 ℃, and decomposition begins above 100 ℃, decomposes above 180 ℃, and decomposes violently and turns black above 200 ℃.

PVC can burn on flames and self extinguish after ignition. During combustion, it degrades and releases low molecular compounds such as HC1, CO, and benzene. Pure polyvinyl chloride (PVC) exhibits weak blue-green fluorescence under the irradiation of ultraviolet monochromatic light, which ages and darkens its color under long-term light exposure. Polyfluoro/vinyl plastics have good stain resistance, but they slowly decompose under light (especially at wavelengths of 270-310nm) and oxygen, releasing H0, forming a double bond and discoloring.

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