The Stabilizer Is Hydrophilic
Stabilizer, also known as stabilizer, has a hydrophilic, can improve the viscosity of the liquid material and dairy cold drinks expansion rate, to prevent the generation of large ice crystals to reduce the rugged feeling, the resistance of dairy products to melt the strong resistance, So that products are not easy to melt and recrystallization, in the production can play a role in improving the state of the organization.
Many types of transparent PVC products, when exposed to water or water vapor for a long time, Stabilizer exhibit a whitening appearance of whitening. Soft products are more powerful than hard products.
It is thought that this phenomenon is due to the presence of easy-to-hydrate additives or adjuvants in the formulation. If only from the PVC stabilizer analysis, it is due to water immersion, so that the stabilizer precipitation from the PVC, and the occurrence of hydration, the formation of hydrated precipitates on the surface (affecting transparency). In this case, even if the moisture is soaked, the stabilizer can not be returned to the original, Stabilizer only the elevated temperature, so that the compatibility of the stabilizer has been restored in order to become transparent.
Tests show that the stabilizer contains almost alkaline earth metal salt formulations, especially barium and calcium, are prone to varying degrees of this problem. Contains cadmium or zinc salts of the material, occasionally this phenomenon. Organotin stabilizer generally does not appear this kind of water whitening phenomenon.
PVC products in the outdoor exposure, will also show whitening phenomenon. This is related to the compatibility of the stabilizer. In the metal soap stabilizer, the benzoate with good compatibility with PVC is less than the stearic acid whitening phenomenon. Organotin stabilizers are not prone to whitening, sulfur-containing organic tin is the best, followed by lauric acid, maleate. Add light stabilizer, phosphite, liquid composite stabilizer to a certain extent, can prevent or alleviate the PVC due to exposure to the phenomenon of whitening.
Stress whitening refers to the PVC transparent hard products under the action of mechanical external force, such as bending, stretching, PVC products, such as bending at the local fold, the Department of the phenomenon of whitening. This may be due to the external force of the molecular structure changes, the polymer molecular chain orientation, PVC density changes, while some molecules between the gap, the formation of light scattering, leaving PVC products on the white.
Some experts believe that the addition of high surface energy stabilizer, to make up the molecular chain orientation caused by the gap method is effective. The use of organotin stabilizers can reduce the whitening phenomenon, Stabilizer especially with the use of maleic acid organotin better.