The Dow Chemical Company

Tomkinson, Donald L

Wilhelm E Walles

An in-mold sulfonation system for sulfonating the surface of plastic articles such as plastic containers during molding. Sulfur trioxide is introduced into a pre-mold chamber, converted to a relatively high pressure gaseous sulfur trioxide, and then injected into a mold such as a blow mold immediately before or immediately following full expansion of the formed plastic article in the mold cavity. Neutralization with a gaseous neutralizing agent follows. By controlling the timing and temperature of the in-mold sulfonation step it is possible to produce a plastic article having an effective barrier layer but containing a minimum of undesirable rinseable salts.

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Auburn, MI, United States of America

Tomkinson, Donald L