PVC foam board precipitation & blooming reasons and solutions
PVC foam board after long-term Zhang and competition, the market commonly used foam board basic positioning of the basic types of raw materials identified.
The reason is very simple, with good compatibility with the PVC material in the case of appropriate dosage will not precipitate, only with poor compatibility of PVC materials in the amount exceeds the critical value will precipitate, precipitation is bound to cause more Blooming phenomenon.
PVC foam board often used additives lead salt / calcium zinc stabilizer, yellow and white foam, foam regulator, stearic acid, 60,316 A, PE wax, calcium stearate, calcium carbonate and other such materials
Foaming regulator and PVC best compatibility, can promote the melting and plasticization of PVC, the formation of network gel structure, brightening, and even reduce the material precipitation.
Stearic acid, calcium stearate, 60,316A is an internal lubricant, especially in the 316A molecule with hydroxyl, etc., relatively good compatibility, 60 is an ester lubricant, compatibility is better, stearic acid A little bit special, mainly when the temperature is low, the main lubrication, the amount of more or high temperature will be part of the role of changes in external lubrication even precipitation, calcium stearate easy to form a layer of film on the surface of the device, a long time easy scaling .
PE wax is a high melting point external lubricant, poor compatibility with PVC, high temperatures can form a film of metal and PVC molecules to prevent adhesion. Stabilizer is PVC essential one of the most important additives, and now most of the stabilizer is a complex stabilizer, in order to reduce costs, some manufacturers in which to add paraffin, polyol and other small molecules, not only with the PVC phase Poor performance, but also very easy to cause precipitation.
In order to avoid the occurrence of precipitation, we can take the following measures: First, a variety of lubricants (low middle high melting point, internal and external slip agent) with coordinated use, complement each other to make up for deficiencies; Second, to ensure non-stick model Try to reduce the amount of external lubricant, in the case of liquidity and plasticization to minimize the amount of lubricant; third, the choice of stabilizer, try to choose high quality and high price, do not understand can find our JuBang alibaba platform; the fourth , Add a small amount of ultrafine silica precipitation will have some improvement.