LDPE, additives Slip agents

LDPE or HDPE extracts has been determined colorimet-rically at 430 nm by oxidation with H202 in the presence of H2S04 [66]. p-Phenylenediamine derivatives such as Flexzone 3C, used as antiozonants in rubber products, have been determined colorimetrically after oxidation to the corresponding Wurster salts [67]. A wide range of amine AOs in polyolefins has been determined by the p-nitroaniline spectrophotometric procedure [68]. Monoethanolamine (MEA) in a slip agent in PE film has been determined as a salicylaldehyde derivative by spectrophotometric quantification at 385 nm [69]. Table 5.6 contains additional examples of the use of 1JV/VIS spectrophotometry for the determination of additives in polymers. 

Slip, antislip, and antiblock agents [30, 31] do not facilitate molding or semifinished product manufacture as do lubricants. What they do is to simplify further processing - of foils in particular. Foil bags that have been stored in stacks cannot be readily picked up or opened, problems that are particularly noted with LDPE and PP. An effective slip agent with LDPE is addition of 0.05 % oleic acid amide and with PP the same amount of eruca acid amide. Additive manufacturers supply concentrates of these compounds in granulate form for addition to molding compounds [50]. 

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