Silica anti-blocking agents

Perhaps the simplest use of colloidal silica in this area is its use to firictionize and coat the film base material to both make it easier to be conveyed through the process and also to prevent it from blocking or adhering to itself when rolled up. The use of colloidal silica as an anti-blocking agent is discussed above under the Surface Modification of plastic films. 

As many film formulations contain both anti-blocking agents and slip aids, combination products are sold by some silica manufacturers. The combination products consist of synthetic silica and a slip aid such as erucamide or oleamide. The combination products show additional benefits through more rapid development of slip and greater anti-blocking efficiency due to better dispersion of both additives. 

Keywords anti-blocking agents, blocking, silica, synthetic silica, clay, diatomaceous earth, talc, coefficient of friction, quartz, masterbatches, slip, slip aids. 

Catalyst component scavengers Processing aid/lubricants, release agents Anti-block agents - silica/talc Flame retardant... 

Many chiral derivatization reactions were used and the compounds examined are mostly amphetamines, /3-blocking agents, amino adds, and anti-inflammatory drugs. Silica gel and, to a lesser extent, silanized silica were used as stationary phases. The Rf values obtained for the diastereomeric pairs were not usually very high (0.04 -0.07), with the exception of amino alcohol and amino acid diastereomers obtained with Marphey s reagent, a derivative of L-alanine amide (0.06 - 0.22). 

Ampacet Product 100520 is a mineral anti-block that does not require hazard labelling as it does not contain heavy metals or diatomaceous earth. At 2.5% usage the 20% loaded LDPE-carried anti-block attains 5000 ppm active antiblock, with films showing 96% light transmission and 12.8% haze. Slip and antiblock agents based on Dow s Affinity polyolefin plastomers include Ampacet 100329 (slip), which contains 5% erucamide, and 110342 (anti-block), which contains 20% diatomaceous silica. 

The amorphous synthetic silicas, fumed and precipitated, are widely used as thixotropes in thermoset polyester resins and gel coats and in PVC plastisols. They are also used as anti-blocking, anti-slip, anti-plateout and flatting agents. Fine groimd natural silicas find some use in thermosets to improve dimensional stability, thermal conductivity and electrical resistance at low cost. 

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