In the early 1970s, the plastics industry began to use silicone materials, and silicone oils were initially used as internal plastic lubricants and release agents for PE injection molding. Due to their incompatibility with polyolefins, low molecular weight liquid silicones migrate to the surface and spread; this greatly limits the application of such silicone oils, for example, when plastics need to be printed, painted or contact food
. These problems can be solved if ultra-high molecular weight (UHMW) polydimethylsiloxane is used instead of ordinary low-viscosity or medium-viscosity silicone oils. Products over 10 are called silicone resins. The viscosity of ×106mm2/s makes them unable to move and enrich on the surface. However, they also have disadvantages. Since they cannot be quantitatively dosed, they are difficult to use in the continuous mixing process of plastics.
In recent years, a new product line has been put into use. It combines the advantages of ultra-high molecular weight polydimethylsiloxane and the easy quantitative addition of solid particles. It is an ultra-high molecular weight silicone masterbatch that does not contain organic carriers.
The main performance requirements of processing additives are as follows:
improve processing and fluidity, eliminate melt fracture, reduce die accumulation, reduce extruder torque, increase production capacity, better mold filling and demolding, improve surface smoothness and gloss, and do not adversely affect polymer properties such as mechanical properties. Generally speaking, adding 0.1-1% of silicone masterbatch can improve processing performance. If there is a positive effect on surface and mechanical properties, 1-3% is required.
Silicone and siloxane materials have a wide range of commercial uses due to their unique properties. Among them, the rapidly developing plastics industry has a great demand for them. New additive silicone masterbatches can greatly improve the processing and fluidity of thermoplastic polymers. At the same time, these performance improvements will not have any effect on other material properties; on the contrary, it can also improve mechanical properties such as impact strength and tensile strength. In addition, the use of additives far below 1% can greatly improve the surface properties of smoothness and gloss.
The advantage of silicone masterbatch is its wide range of applications. Almost all thermoplastic processing needs can be met with just one product; due to the high silicone content, the amount used is small.
