How to delay and stop PVC heat shrink film aging phenomenon?

PVC heat shrink film in the processing, storage and use of the process, in the light, heat, oxygen under the action of the aging phenomenon will occur fading, embrittlement, cracking. pvc heat shrink film in order to delay and stop the aging phenomenon, must be added to the stabilizer. Mainly used to prevent heat aging, called heat stabilizers; mainly used to prevent oxidative aging, called antioxidants; mainly used to prevent light aging, called light stabilizers, which are collectively referred to as stabilizers.

 Today's best performing PVC heat shrink film stabilizers are methyltin heat stabilizers, which are very effective in calendering, extrusion, injection and blow molding of rigid polyethylene (PVC). Because of its high safety, it is especially used for packaging high-definition rigid polyethylene products, and at the same time, it is also commonly used in aluminum doors and windows, water piping, decorative materials to replace other highly toxic plastic heat stabilizers. It has been widely used in the United States, Europe, Japan. In recent years, 181 methyl tin heat stabilizer began to be applied in large quantities in China. The additives that can improve the flame resistance of PVC heat shrink film are called flame retardants. Most of the plastics containing flame retardants have self-extinguishing, or slow down the burning rate. Commonly used flame retardants are antimony oxide and aluminum, boron compounds, halides and phosphate esters, tetrachlorobenzene dicarboxylic anhydride, tetra-O-benzene dicarboxylic anhydride and so on.

PVC heat shrink film for the amorphous structure of the white powder, small degree of branching, relative density of 1.4 or so, the glass transition temperature of 77 ~ 90 ℃, 170 ℃ or so began to decompose, poor stability to light and heat, above 100 ℃ or after a long period of exposure to sunlight, it will decompose and produce hydrogen chloride, and further autocatalytic decomposition, causing discoloration, physical and mechanical properties also decline rapidly, in practical applications. In practical application, stabilizers must be added to improve the stability to heat and light.