Plastic Additive are chemicals that are dispersed in the plastic molecular structure and do not seriously affect the molecular structure of the plastic, but can improve its nature or reduce the cost. The addition of additives can promote the plastic to improve the substrate processing, physical, chemical and other functions and increase the physical and chemical properties of the substrate.
There are several main categories of additives:
(1) antioxidant plastic unsaturated double bond in the oxygen atoms, heat and light caused by the invasion of free radicals, resulting in chain reaction, the molecular chain breakage or the formation of chain cross-linking, resulting in the strength of plastic products Reduce or become brittle. Antioxidant function is to delay the decomposition of plastic due to oxidation, extend the life of plastic products
(2) antistatic agent antistatic agent is the main function of giving plastic to produce electrical conductivity, so as to avoid friction caused by the accumulation of static electricity. Commonly used antistatic agents are quaternary ammonium salts, ethoxylated amines, fatty acid esters and sulfonated waxes.
(3) foaming agent plastic blowing agent mainly has three categories: ① nitrogen, carbon dioxide and air, directly into the plastic melt to make foam; ② volatile liquid such as butane, pentane, petroleum ether, Chloromethane and so on, after the temperature of the volatilization expansion, leaving the plastic body foam, the common polystyrene foam that belongs to this type; ③ decomposition of chemical blowing agent, such foaming agent is generally solid powder, they are Heat the decomposition of the release of gas (usually nitrogen or carbon dioxide), leaving the plastic cell-like structure, and reduce the weight. These foaming agents are mostly organic azo compounds such as azobisdicarboxamide and azobisisobutyronitrile. Foam plastic are: ABS, PS, PVC, PU, EVA, PE, PP and so on.
(4) flame retardant When the addition of flame retardant plastic exposed to the flame, can inhibit the spread of the flame itself to prevent the formation of smoke,Plastic Additive when the flame is removed when the combustion will stop. Plastic flame retardant principle can be divided into three categories:
① reactive type of flame retardant can react with oxygen to form an inert gas, enveloped in the combustion of the surrounding, reduce the combustion of oxygen content, in order to achieve the purpose of burning. Any combustion can produce CO, CO2, NH3 and halogen compounds, such as PVC, PU foam, polyester or epoxy resin are selected this method.
② non-reactive flame retardant is a halogen, phosphorus, nitrogen or boron compounds, when the combustion occurs, you can break down an inert material, covering the surface of plastic combustion, the formation of a layer of obstacles to isolate the outside world Of oxygen,Plastic Additive to achieve the purpose of fire.
③ waterborne oxides such as alumina flame retardant encountered combustion, can release the water vapor, the combustion process to absorb the heat, so that the temperature around the combustion material to reduce the spread of the flame to prevent the formation of smoke.
(5) Lubricant Lubricants can be divided into internal lubricants and external lubricants, the main function of the internal lubricant is to improve the internal mobility of resin, resin molecules to reduce the internal friction, such as fatty acids (stearic acid Monoglycerides); external lubricants in the resin to reduce the adhesion of the processing machinery, and improve the smooth surface of the product easy to mold.
(6) impact resistance modifier impact resistance modifier is usually a special resin to add the way to knead, and improve the impact resistance of plastic. Impact-resistant modifiers often affect the heat resistance, fluidity or processability of plastics, and must be carefully chosen.
(7) plasticizer Most of the synthetic resin has plasticity, but the plasticity of the size is not the same, in order to make the resin easy to plasticize and impart the flexibility of the product, generally add some low molecular weight resin, these low molecular Plasticizer. Plasticizer is a liquid or low melting point material, and resin should have good miscibility. Commonly used plasticizers are phthalate esters,Plastic Additive aliphatic dibasic acid esters, phosphates, chlorinated paraffin and so on.
(8) coloring agent is to beautify and decorate the plastic in the material to add the pigment containing additives called colorants.
(9) the filler is added to the plastic batch to reduce the cost, and sometimes can enhance the physical properties of plastic
The relatively inert substances such as hardness, stiffness and impact strength are called fillers. The most commonly used fillers are clay, silicate, talc, carbonate and so on.
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