PVC (polyvinyl chloride) pellets special for ultrahigh-transparency hard medical injection molding apparatuses

Abstract

The invention discloses PVC (polyvinyl chloride) pellets special for ultrahigh-transparency hard medical injection molding apparatuses. The PVC pallets comprise, by weight, 100 parts of polyvinyl chloride resin with the degree of polymerization being 700, 3.0-4.0 parts of methacryIate-Butadiene-Styrene copolymer, 1.5-2.0 parts of methacrylate processing aid, 2.0-2.2 parts of methyltin mercaptide heat stabilizer, 2.0-2.3 parts of butyl dodecanoate lubricant, 0.2-0.3 part of stearic acid, 0.1-0.25 part of oxidized polyethlene wax and trace indigo pigment. The finished products are prepared by means of feeding the components into a high-speed heating mixer according to the proportion for high-speed mixing, performing kneading to the temperature of 123-125 DEG C prior to discharging, putting the discharged material into a low-speed cooling mixer to be cooled to room temperature to obtain mixed powder, feeding the mixed powder into a pelletizer for pelletizing, and cooling the pellets to the temperature lower than 40 DEG C prior to packaging. The medical injection molding apparatuses made of the PVC pellets have ultrahigh transparency and surface glossiness.

Description

technical field [0001] The invention relates to a PVC pellet, in particular to a special PVC pellet for ultra-high transparency rigid medical injection molding equipment, and belongs to the technical field of plastic pellet production and processing. Background technique [0002] As a general-purpose plastic, PVC resin (polyvinyl chloride) is widely used in various food packaging, pharmaceutical packaging, cosmetic packaging, household appliance packaging, auto parts, and chemical materials due to its relatively low price and ease of processing after modification. , architectural decoration building materials, fire equipment accessories, sanitary ware, supermarket shelves and other fields. [0003] Polyvinyl chloride is a highly polar polymer with strong intermolecular forces. It needs to be heated to a certain temperature to show its plasticity. Rigid and highly transparent PVC materials suitable for injection molding can usually only be processed at temperatures above 180...

AI Technical Summary

Problems solved by technology

However, there is still a technical bottleneck at present: due to the addition of the above-mentioned various additives and the influence of the quality of the PVC resin itself, it will have a greater impact on the transparency of the transparent rigid PVC pellets, especially in the injection molding process. When the material flows through the flow channel at high speed, it will produce instantaneous high friction between molecules, which is very easy to cause discoloration or zooming of the material. ester) to reduce the instantaneous high friction between molecules, and it is precisely because the addition of this excessive general-purpose internal lubricant has a great impact on transparency that it is impossible to obtain PVC products for medical injection molding devices with ultra-high transparency

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