Selection of plastic additives High polymer resins show different processing characteristics due to different structures, and can be divided into thermoplastic and thermosetting resins, crystalline and amorphous polymers accordingly. Different types of resins have different processing methods, and the same type of resin has different processing and molding methods due to different uses of the final product, such as: blow molding, injection molding, slush molding, rotational molding, casting, calendering, extrusion, etc. Similar plastic products have different functional requirements and different functional plastic additives due to their different application industries.
The thermal stability of some plastic additives is too high, which may also limit its function. If the decomposition temperature of the foaming agent is higher than the foaming molding temperature, the flame retardant cannot generate effective substances or active free radicals that capture free radicals, block the combustion chain reaction, etc. when the flame retardant substrate is thermally decomposed.
Compatibility with the base resin In addition to considering its necessary functions, the selection of additives must also start from the similarity and difference in the structure of the base resin and plastic additives to judge the compatibility of the two. Plastic additives have good compatibility with the base resin, so that they will not deteriorate (possibly improve) the physical-mechanical properties of the substrate, and can also improve migration resistance and extraction resistance. The basis for judging the compatibility of the two is mostly based on the principle of similarity compatibility. Similar structures, similar polarities, and similar molecular weights are all conducive to the improvement of compatibility. For those additives that have poor compatibility with the base resin and it is difficult to increase the amount of additives, it is necessary to try to improve or improve their compatibility, such as using a compatibilizer or a coupling agent to conduct fine chemicals.