pvc internal and external lubricant selection principles
(1) pvc external lubricants generally lower than the melting point of the molding processing temperature 50-60 ℃.
( 2 ) to be reasonable taking into account liquidity, the rate of release of plastics and plasticizers . To balance the internal and external lubricants .
Early ( 3 ) to maintain the system, metaphase, anaphase lubrication integrity.
( 4 ) do not adversely affect the secondary processing ( heat sealing , laminating , printing, etc. ) .
( 5 ) the lubricant in the resin PVC stabilizer for fittings dispersion, the dispersant is added when necessary. ( 6 ) to pay attention to the interaction with other additives ( plasticizers , heat stabilizers , antioxidants , fillers , impact , etc. ) is .
pvc internal and external lubricant previously mainly used for PVC in recent years, the rapid growth in the amount of polyolefins and engineering plastics , the required amount is close to the amount of PVC . Currently , in use , many plastics factory has its own proprietary formula. Recently , the application of polymer blends alloys are widely used, the demand for these products will have great growth. And homopolymer, copolymer compared to the lubricant composition and formulations vary , according to the special requirements of users in research and development , which is a new direction for the development of pvc internal and external lubricant . Production profiles, sheet extrusion , injection molding products , hollow products , blow film are highly transparent products have a high degree of plasticizing , high Aluminum hydroxide liquidity , and therefore require a higher plasticizing rate, so the pvc to more lubricants ; pipe and for the purpose of producing , in its plasticization is preferably 60% to 70% [ 8 , 9 ] , which requires a low rate of some plasticizer , the lubricant should be relatively little outside ; for calendering process , in order to melt the PVC calender rolls easily peeled , external lubricant should be a little more ; while the injection molding process will have as little as possible with external lubricant for external lubrication to minimize the impact of falling weld line strength .
PVC external lubrication balanced Titanium dioxide rutile diversity in fact different types of processing equipment, such as extrusion ( divided into single and twin screw ) , injection molding, calendaring , require different lubrication balance. Strictly speaking, the same equipment , products of different manufacturers , and even the same device with the new balance of old have different lubrication requirements . Different types of products , such as pipes, films, sheets and profiles , and have different lubrication balance.
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