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History of Silicone additives / Silicone masterbatch/ Siloxane masterbatch and how it works in wire & cable compounds industry?

Silicone additives with 50% functionalied silicone polymer dispered in carrier like polyolefin or mineral , with form of granular or powder, widely used as processing aids in wire & cable industry. Well-known products like SILOXANE MB50 series work as lubricant or rheological modifier in wire & cable industry and it was first introduced from Dow Corning in the United States twenty years ago, then the alternative SILICONE MASTERBATCH MB50 appeared in the market with 70% functionalized silicone polymer dispersed in carrier like silica, with form of granular as well, then products from Chengdu Silike appeared in the market from the year of 2004, with silicone content from 30-70% and granular or powder form.  

The technical parameters of commercial silicone masterbatch should include the following content:

(1) When work as lubricant or rheological modifier, the content ranges from 5 to 50%

(2) Carrier should compatible with silicone and the user’s main formula substrate should be considered, with polymer name indication and melt index of the carrier, so that users can refer to it when designing the formula. If inorganic mineral powder is used as the carrier, the powder name should be indicated. The whiteness and fineness of inorganic powders are crucial for customers, and white and micron sized powders should be chosen as much as possible for production.

When work as lubricants or rheological modifiers

For Polyethylene material

As is well known, the phenomenon of “shark skin” often occurs when extruding polyethylene insulated or sheathed wires and cables, especially when extruding linear low-density polyethylene (LLDPE) or ultra-low density polyethylene (ULDPE or POE). Extruded cross-linked polyethylene materials (whether peroxide cross-linking or silane cross-linking) also occasionally experience “shark skin” phenomenon, due to inadequate consideration of the lubrication system in the material formula. The current international practice is to add trace amounts of fluoropolymers to the formula, but the cost is high and the application is limited.

With a small amount of ultra-high molecular weight silicone (0.1-0.2%) to polyethylene or cross-linked polyethylene can effectively prevent the generation of “shark skin”. At the same time, with its lubrication effect, it can effectively reduce the extrusion torque to prevent the dragging motor from stopping due to overload.

Silicone used as a lubricant, due to its minimal addition, must be evenly distributed in the material in order for it to function during the processing. Due to the chemical inertness of silicone, it will not react chemically with the components in the formula. It is recommended that the cable material factory evenly mix silicone into the plasticizing granulation process to facilitate the use of the cable factory.

For Halogen free flame retardent(HFFR) cable compounds 

Due to the presence of a large amount of flame retardants (mineral powder) in HFFR cable compounds, which result a high viscosity and poor flowability during processing; The high viscosity makes it difficult for the motor to drag during extrusion, and the poor fluidity results in a small amount of glue produced during extrusion. So, when the cable factory extrudes halogen-free cables, the efficiency is only 1/2-1/3 of polyvinyl chloride cable.

With a certain amount of silicone in the formula, not only processing like flowability improved but also get a better flame retardancy for the material.