Ppg Industries, Inc.

James A Barter

Robert H Tang

Henry C Stevens

David E Kellar

John F Van Hoozer

Organic peroxydicarbonates represented by the following graphic formula are described. ##STR1## In the formula, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from an alkyl group containing from 1 to 4 carbon atoms. R.sub.1 and R.sub.2 and/or R.sub.3 and R.sub.4 can participate in a cycloalkyl group having from 3 to 6 carbon atoms. The peroxydicarbonates are useful as initiators for the polymerization or copolymerization of ethylenically unsaturated monomers or the cross-linking of unsaturated polyester resins. The organic peroxydicarbonates can be used in combination with commercially available peroxydicarbonates, particularly those having a longer half-life, or with peresters, diacylperoxides and azo compounds.

Alkyl percarbonates

A process for preparing peroxydicarbonate is disclosed wherein a mixture of chloroformate and dilute aqueous hydrogen peroxide is reacted with a dilute aqueous alkali metal hydroxide solution.

Production of peroxydicarbonates

Silicone rubber is vulcanized by heating in the presence of an organic peroxide initiator. Known tertiary-alkylperoxy alkyl carbonates are used in the vulcanization of molded silicone rubber articles, but have not been recommended for use in hot air vulcanization. The tertiary-alkylperoxy alkyl carbonates of the present invention provide good cures with all curing methods, including hot air vulcanization.

Tertiary-alkylperoxy alkyl carbonate initiators for hot air

Ethylenically unsaturated material susceptible to free-radical polymerization, e.g., vinyl chloride and unsaturated polyesters, is polymerized, e.g., in an aqueous medium with an alkaline buffering reagent and an initiator system comprising an acid anhydride, e.g., isobutyric anhydride, and a peroxygen compound selected from an organic peroxy acid (peracid), e.g., peracetic acid, and hydrogen peroxide. Optionally, a further organic free-radical type initiator, e.g., lauroyl peroxide, a dialkyl peroxydicarbonate or azobisisobutyronitrile, is used in combination with the acid anhydride and peroxygen compound. Preferably, the anhydride and peroxygen compound are introduced separately into the polymerization medium. It is believed that at least a portion of the anhydride combines with the peroxygen compound to form the corresponding diacyl peroxide.

Organic acid anhydride-peroxydicarbonate composition

A solid, frozen organic peroxide emulsion comprising from 30 to 75 weight percent organic peroxide, an emulsifying amount of surfactant(s) and the remainder water is described. Organic peroxides described include: dialkyl peroxydicarbonates, e.g., di-secondarybutyl peroxydicarbonate, diacyl peroxides, e.g., diisobutyryl peroxide, and acyl sulfonyl peroxides, e.g., acetylcyclohexylsulfonyl peroxide. The surfactant can be anionic, cationic, or nonionic, preferably nonionic, or mixtures of compatible surfactants.

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Akron, OH, United States of America

James A Barter