Transparent PVC heat stabilizer several factors affect
2013-07-03 by wsdchemical
PVC heat stabilizer of transparency is determined by the following factors.
1, the refractive index of the stabilizer
PVC resin, heat stabilizer and 1.52 to 1.55 of the refractive index of the visible light are the same or similar, then the better the transparency of PVC products, the transparency is low and vice versa.
2, stabilizer molecules (molecules) of linear length
Heat stabilizer molecule (or molecules) linear length is less than 400 ~ 735nm wavelength of visible light refracting fewer higher degree of transparency, whereas less transparent.
3, a heat stabilizer in PVC, "solubility", ie compatibility
The so-called compatibility of two or more substances refers to the mutual affinity when mixed. Good compatibility is possible to achieve dispersion of the molecular level. Thermal stabilizer in the molten state has good compatibility with PVC resin. Do not form a two-phase, that is no interface or the interface is not obvious, less refracted light, PVC products, higher transparency. Liquid stabilizer than the corresponding solid metal soap good compatibility in PVC, the linear molecule has a smaller length, and thus the higher the transparency of the PVC.
Liquid organic tin heat stabilizer preferably transparent, it is not participate because both thermostable reaction heat stabilizer itself, or has participated stabilized R2SnCl2 generated after the reaction of PVC resins have good compatibility. The Ba / Zn, Ba / Cd, Ca / Zn stearate soap in PVC certain compatibility has relatively high transmittance, but because of the limited compatibility, the linear molecule has a larger length, participate product after thermal stabilization is typically metal salts, such as CaCl2, BaCl2, etc., poor compatibility with PVC, and therefore there are more due to a large amount of reflected light to affect the transmittance becomes cloudy.
Poor compatibility tribasic lead sulfate, dibasic lead phosphite, molecules and relatively large, and thus opaque PVC products.