PVC products are widely used in daily life, but they may also have some problems during use. Today, the manufacturer of Sainuo polyethylene wax will take you to learn about the whitening problem of PVC products.

When PVC products are exposed to heat outdoors, due to the effects of moisture, carbon dioxide, sulfur dioxide, and light in the air, they will exhibit whitening phenomenon, mainly due to the following three reasons:
1. Whitening after water immersion
Many types of transparent PVC products exhibit a white haze appearance when in contact with water or steam for a long time. Soft products are more powerful than hard ones. Due to the immersion of water, plasticizers, stabilizers, etc. precipitate from PVC and undergo hydration, forming hydrated precipitates on the surface (affecting transparency). Even if the soaked water is gone, plasticizers and stabilizers cannot be returned to their original state. Only by increasing the temperature can the compatibility between plasticizers and stabilizers be restored before they can become transparent.
2. Whitening after exposure to sunlight
PVC products exposed to sunlight outdoors can also exhibit whitening due to the effects of moisture, carbon dioxide, sulfur dioxide, and light in the air. This is related to the compatibility of stabilizers. In metal soaps, benzoates with good compatibility with PVC exhibit less whitening than stearates. Organic tin is not easy to whiten, and sulfur-containing organic tin is the best, followed by lauric acid salts and maleate salts. Adding light stabilizers, phosphite esters, liquid composite stabilizers, etc. can to some extent prevent or alleviate the whitening phenomenon of PVC caused by exposure to sunlight.

Hard PVC products will turn white after exposure in Florida or other damp places, but will not remain white when exposed in Arizona. So, humidity is a condition that promotes the whitening of PVC by exposure to sunlight.
3. Stress whitening
Stress whitening refers to the phenomenon of whitening in local areas of PVC products, such as bending, creases, and stretching areas, under the action of mechanical external forces.
This may be due to the change of molecular structure caused by external force, the orientation of polymer molecular chain, the change of PVC density, and the appearance of voids between some molecules to form light scattering, which makes the PVC products appear white.

4. Other whitening
During the processing of PVC transparent products, if an excessive amount of lubricant is used, more lubricant precipitates can also cause the transparent products to produce white turbidity, which is sometimes referred to as whitening.
This whitening phenomenon usually results in obvious wax like substances on the surface of the product. The solution is to reduce the amount of lubricant used or switch to a lubricant with better compatibility, so as to achieve a balance between the internal and external lubrication of the formula.
For more details, please consult us!
Qingdao Sainuo Group. We are manufacturer for PE wax, PP wax, OPE wax, EVA wax, PEMA,EBS,Zinc/Calcium Stearate…. Our products have passed the REACH, ROHS, PAHS, FDA testing.
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