Chlorinated polyvinyl chloride DN400 loose flange once injection moulding technique and device thereof

Abstract

The invention relates to a production process of a resin flange, in particular to a one-time injection molding process and equipment for a chlorinated polyvinyl chloride loop flange. The process includes batching, drying, injection molding, pressure holding, and mold opening process. During the injection molding process, the heating part of the barrel of the injection molding machine is divided into seven sections, and the temperature range of each section is 150-155°C and 168-173°C. , 162~167℃, 160~165℃, 155~160℃, 150~155℃, 145~150℃, the mold temperature is controlled between 60~70℃; the injection pressure during injection molding is divided into three sections, respectively 56MPa , 59MPa and 76MPa. The pitch of the injection molding machine screw used in the method is equal to the diameter of the screw, the feeding section accounts for 25% of the total length, the compression section accounts for 50% of the total length, and the homogenization section accounts for 25% of the total length. The invention realizes the one-time injection molding of the DN400 large loose sleeve flange through the improvement of the process and equipment.

Description

technical field [0001] The invention relates to a production process of a resin flange, in particular to a one-time injection molding process and equipment for a chlorinated polyvinyl chloride loop flange. Background technique [0002] PVC-C (chlorinated polyvinyl chloride) is produced by the chlorination of PVC free radicals. The general chlorine content is 63% to 69%. Different chlorination methods, states and chlorine reactions, the resulting PVC-C has Big difference. Its chlorination reaction process is as follows: [0003] start up: <chemistry num="0001"> <chem file="200610150658_CML001.XML" / > < / chemistry> [0004] Derivation: RH+Cl→R+HCl [0005] R+Cl 2 →RCl+Cl [0006] Termination: R+Cl→RCl [0007] Cl+Cl→Cl 2 [0008] R+R→R 2 [0009] (RH stands for PVC, → stands for heating) [0010] PVC-C is produced according to the chlorination reaction mechanism of PVC free radicals mentioned above, controlling a certain percentage of chlorine co...

AI Technical Summary

Problems solved by technology

[0011] DN400 looper flange refers to a large-scale looper flange with a nominal diameter of 400. When the existing process is used for one-time injection molding of DN400 looper series flanges, the following problems often exist: (1) due to PVC-C ( Chlorinated polyvinyl chloride) resin has a large proportion of raw materials, and the torque generated by the screw of the injection molding machine in the pre-molding exceeds the design requirements of the standard screw; (2) PVC-C (chlorinated polyvinyl chloride) resin has high chlorine content and temperature control The range deviation is small, and the friction heat generated by the screw during pre-molding is difficult to control, so the pre-molding time required for the DN400 loop flange is long, and the material is easily burnt in the barrel; (3) PVC-C (chlorinated polyvinyl chloride) Vinyl chloride) resin has good toughness, high impact strength, and large cutoff. In the process of processing, the rotation speed of the injection molding machine oil motor is unstable during pre-molding.

Due to the above reasons, according to the existing technology and process, it is impossible to solve the problem of one-time injection molding of DN400 looper series flanges

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