The Goodyear & Tire Rubber Company

James R Purdon, Jr

Dane Kenton Parker

Gary Lee Burroway

Robert F Roberts

A polymeric article which is subject to attack by oxygen ozone and/or ultraviolet light is coated with a thin coating of a polymer which is resistant to oxygen, ozone and UV light. It protects the article from cracking or degradation due to any of these causes. The uncoated article serves as a substrate. The substrate may be any polymer which is subject to attach by oxygen, ozone and/or ultraviolet light. A preferred coating is cured from a highly saturated polymer having only a small amount of unsaturation, as for example, hydrogenated nitrile rubber (HNBR, or hydrogenated nitrile/butadiene copolymer), highly saturated styrene/butadiene copolymer, hydrogenated polybutadiene, or hydrogenated styrene/vinylpyridine/butadiene terpolymer. The hydrogenated or highly saturated polymer of the coating is obtained by hydrogenating an unsaturated polymer which is a polymer of 1,3-butadiene (5-100% by weight) and optionally one or more monoethylenically unsaturated polymers (0-95% by weight). The cured coatings are typically elastomeric. The coating is applied as an uncured highly saturated polymer latex, which is dried and cured in place on the substrate to yield the desired coated article. The thickness of the coating may be about 0.5 mil (0.0005 inch) up to approximately 10 mils (0.01 inch).

Rubber article having protective coating

Very low molecular weight polymers are sometimes used in toners which are designed for high speed printers and copiers. It is extremely difficult to prepare polymers having the ultra-low molecular weights required in such applications by standard emulsion polymerization techniques. By utilizing the techniques of this invention, the molecular weight of polymers made by conventional emulsion polymerization can be reduced to a very low level. This invention more specifically discloses a process for preparing a low molecular weight polymer which is particularly useful as a toner resin, which comprises (1) treating an emulsion of a polymer having a number average molecular weight which is within the range of about 18,000 to about 40,000 and which is comprised of repeat units which are derived from about 65 to about 95 weight percent of a vinyl aromatic monomer, from about 1 to about 12 weight percent of a conjugated diene monomer, and optionally from about 1 to about 34 weight percent of an alkyl acrylate monomer, with ozone in an amount and under conditions which are sufficient to reduce the number average molecular weight of the polymer to within the range of about 3,000 to about 15,000; and (2) recovering the polymer from the emulsion.

Method for preparing ultra-low molecular weight toner resin

The subject invention relates to a process for treating an emulsion of a crosslinked elastomeric polymer containing residual hydrazine to obtain a latex of soluble elastomeric polymer having a reduced concentration of residual hydrazine therein, said process comprising the addition of ozone to said emulsion in an amount and under conditions which are sufficient for the ozone to react with the crosslinked elastomeric polymer and the residual hydrazine to produce a latex of soluble elastomeric polymer having a reduced level of residual hydrazine therein. The process of the present invention also improves the color of latex by removing color-bodies, such as benzoquinone, which may be present in the original latex.

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Stow, OH, United States of America

James R Purdon, Jr