2014年2月9日星期日

Use the principle of PVC processing aid

In industrial production, in order to improve production processes, improve product quality and yield, or to give the product of a specific application performance by adding auxiliary chemicals. Also known as the additive. However, as an important component of the product matrix, the product shape, structure, performance of large doses have a significant impact of additional material, generally not included in the scope of aid. Additives wide range of applications, usually re-dubbed the role of one pack stabilizer  object names, such as polymeric additives, water treatment, metal surface treatment agent. There are some common additive selection considerations, such as: ① use of the additive requirements. Additives appearance, odor, contamination resistance, durability, electrical properties, weather resistance and so the use of direct impact products. ② processing conditions additives adaptability. ③ durability additive. Loss additive mainly through evaporation, extraction and migration pathway 3, the species must be selected appropriately according to the environment and the article processing conditions. ④ compatibility with polymer additives. Comprises mixing in impact resistance and stability of each may be a problem between them. ⑤ additive toxicity. Food and drug packaging materials, water pipe, medical equipment and other polymer materials, products, their health mainly depends on additives used. ⑥ synergistic and additive effect between proposition. If chosen appropriately, the mutually reinforcing, and can reduce the total amount of additives. The use of additives principles:
The current provisions of the international system can be divided into two, one is to allow the use of additives "exhaustive" "whitelist" lists, and the other is listed aids disabled "disabled list." After years of practice, "disabled list" to be found there is a big drawback: the lack of new substances binding. Plastic profiles Promoters
Additives a plastic profiles: impact modifiers, such as the production of plastic profiles without impact modifier, plastic profiles will be very brittle, a little collision, easily broken. Commonly  chromium oxide Titanium dioxide rutile used in the production of plastic profiles impact modifier modifier consists of the following three categories: chlorinated polyethylene, polyacrylate, ethylene - vinyl acetate copolymer. Plastics Additives two sections: heat stabilizers plastic profiles are heat-sensitive plastic, so plastic profile production machining, heat stabilizers is essential. Metal heat stabilizers in PVC can absorb decomposition of HCL, it can slow down the rate of decomposition of plastics and extended decomposition time, the production of plastic profiles for the most commonly used compound lead salt, high-efficiency thermal stability, low prices. Plastics Additives three  sections: the main processing aid processing aids plastic molding  PVC lubricants process in order to improve the performance improvements and the development of a class of additives. Plastic profile processing temperature and decomposition temperature relatively close, poor mobility, easy to stick on the device coking, and therefore the production of plastic profiles need a certain amount of processing aid to overcome the defects of plastic profiles itself.

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