(Dibutyltin dilaurate T-12) is a good lubricity of all organotin stabilizers, has very good weatherability and compatibility, no sulfide pollution, no ooze. Lauric acid type organotin and metal soap can be used to achieve satisfactory results, but its stability is poor, and the initial colour, suitable for varieties with sulfur, mainly for the manufacture of transparent plastic shoes, transparent flexible film transparent hose, etc.. Its addition amount is 1.2~2.0 parts, generally with liquid barium. Zinc, barium. Cadmium. Zinc is used to improve its initial colour and to reduce costs accordingly.
PVC heat-shrinkable film products are different from soft and hard ones. In general, the amount of plasticiser in the formula is 10 PHR (PerHundredResin, which means the number of parts of formula material required per 100 mass parts of resin) or less is called rigid products; the amount of plasticiser in the range of 10 to 40 PHR is called semi-rigid products; the amount of plasticiser over 40 PHR is called soft products.
As PVC is a heat-sensitive plastic, the formulation cannot be without a heat stabiliser. The amount of heat stabilizer in a general PVC formulation is 5 to 8 PHR. if there is less heat stabilizer, it is not enough to stop the PVC from decomposing at the temperature of hot melt forming; if there is more heat stabilizer, it will increase the temperature of hot melt flow.
In order to improve the melt processability of PVC, PVC formulations are melt processable and processing aids should be added to the PVC formulation. PVC processing aids are mainly acrylate resins (ACR) with good compatibility with PVC films, as well as chlorinated polyethylene (CPE), chlorosulphonated polyethylene, methyl styrene polymers, MBS, ABS, etc. ABS, etc. Note: Processing aids should not be added in excess of 12 PHR, as the melt viscosity may be too low and the friction too low for extrusion. Generally, the amount of processing aids should be 5 to 8 PHR!
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