Method for reducing occurrence rate of ABS defective products

Abstract

The invention relates to an evaluation method and measures for controlling crystal points, in particular to a method for reducing the occurrence rate of ABS defective products. According to the method, the size grades and the numbers of crystal points within a unit circle area are automatically recorded through crystal point scanning optical processing statistical software, ABS samples are made into 2-100 ABS finished products by adopting a forming process, whether each group of ABS finished products meet the crystal point requirements or not is observed, the defective product rate of each group of products is determined finally, and the group of ABS samples with the minimum defective product rate is selected, wherein the crystal point size grade and the corresponding crystal point number are determined as crystal point control indexes; a relation curve between the size grades and numbers of the crystal point of different unit circle areas and the filter pressure difference is drawn, the filter pressure difference corresponding to the lowest point of the curve is selected as the optimal filter pressure difference value, and the optimal pressure difference range is determined. According to the method for reducing the occurrence rate of the ABS defective products, the accuracy of the crystal point test is improved, the requirement of downstream processing on the crystal points can be ensured under the condition of not influencing a production device and raw material supply, the occurrence rate of defective products is greatly reduced, and the method has long-term applicability.

Description

technical field [0001] The invention relates to an evaluation method and a measure for controlling the crystal point, in particular to a method for reducing the occurrence rate of defective ABS products. Background technique [0002] ABS resin is one of the five major synthetic resins and is a thermoplastic engineering plastic with a wide range of uses. ABS resin is a terpolymer composed of acrylonitrile, butadiene and styrene. The production process is mainly divided into bulk method and emulsion method. It is usually light yellow or milky white granular non-crystalline resin. The molding process of ABS is divided into: injection, extrusion, calendering, vacuum, blow molding, etc. [0003] The crystal point problem has always been a non-negligible problem in the processing of ABS resin products, mainly affecting the performance and appearance of the product, resulting in quality complaints. Crystal points are generally excessive polymers that cannot be decomposed. When A...

AI Technical Summary

Problems solved by technology

[0003] The crystal point problem has always been a non-negligible problem in the processing of ABS resin products, mainly affecting the performance and appearance of the product, resulting in quality complaints

The detection method disclosed in the CN102233662 patent has the following disadvantages: first, it is not applicable to all thermoplastic resin products, and wire drawing can be carried out for some homopolymer products of high-melt index grades, but it does not consider the ternary components of some low-melt index grades. Copolymers, etc., due to the severe degree of molecular chain entanglement, the filaments are slow to exit, and at the same time the mold is expanded, and the ideal diameter cannot be accurately achieved. The diameter of the wire drawing has a certain range, and the detection of smaller-sized crystal point particles cannot be carried out. Stricter inspection requirements for indicators

Second, there is longitudinal stretching of the polymer during the wire drawing process, which will cause the thickness of the wire to be inconsistent. Considering that the wire is approximately a cylinder, the uneven thickness will cause crystal points to overlap and affect the sensitivity and accuracy of the detection system. It has limitations, for example, if a large size crystal point and a medium size crystal point overlap, only large size crystal points or false size crystal points that are larger after superimposition can be detected

[0007] None of the above technologies combine the processing requirements of downstream processing plants (one or more requirements such as thermoforming, injection molding, etc.) and the operating conditions of production equipment to propose a corresponding evaluation method and control measures for ABS resin.