Dane Kenton Parker

A New Process for the Preparation of Highly Saturated Nitrile Rubber in Latex Form

Abstract A novel process for the preparation of highly saturated nitrile rubber latex has been developed. This process directly converts NBR latex into HNBR latex in one reaction step. The key to the process is the efficient in-situ generation of diimide within the latex by the oxidation of hydrazine hydrate in the presence of a catalyst. At 40–70°C, diimide smoothly and selectively reduces the olefinic bonds while leaving other functionalities unaffected. The process operates at ambient pressures and produces nitrogen and water as by-products. HNBR latex produced by this process has been applied to the manufacture of superior heat-resistant gasketing via the “Beater-Addition” method. This unique new form of HNBR maintains the well known benefits of HNBR (e.g., solvent, heat, and ozone resistance, etc.) while expanding its potential applications into latex-related products.

The preparation, properties and potential applications of diimide-hydrogenated styrene-butadiene (HSBR) and polybutadiene (HBR) thermoplastic elastomers

Abstract Our unique diimide-based process for preparing HNBR latex from NDR latex without the use of hydrogen, noble metal catalysts or solvents has now been successfully extended to the preparation of hydrogenated thermoplastic elastomers latexes directly from SBR or BR latex precusors. Commercially available SBR latex such as SBR 1502 can be readily reduced to high saturation levels (95+%) via the diimide reduction technique. Latex cast films of the highly reduced elastomer show excellent ozone and oxidation resistance as expected. Unexpectedly however, the hydrogenated polymer films demonstrate high tensile strength and thermoplastic elastomer (TPE) behavior. The TPE properties have been found to be caused by polyethylene crystallites that exist even in the unstretched films under ambient conditions. Latex is an unusual physical form for a TPE material. As a latex, TPE elastomers can be fabricated into sheets or other products by simple dipping or spraying methods—methods not normally available to TPEs...

REACTIVELY CURABLE RUBBERS. I, DIENE ELASTOMERS WITH PENDANT ISOCYANATE AND/OR HYDROXYL FUNCTIONALITY

Abstract In conclusion, we have demonstrated that modified diene elastomers containing active hydrogens and/or blocked-isocyanate derivatives can be crosslinked (cured) by three distinct methods. These methods include: 1. reaction of polymer-bound active hydrogens with monomeric polyisocyanates (Type I), 2. reaction of polymer-bound isocyanates with compounds containing two or more active hydrogens (Type II), and 3. reaction between polymer segments that contain both polymer-bound isocyanates and active hydrogens (Type III). Additionally, we have shown that the new polymerizable blocked-isocyanate derivatives (Type II and III systems) can be readily incorporated into SBR and NBR elastomers by standard emulsion-polymerization techniques. The degree and distribution of these monomers within the elastomer matrix were shown to be controlled by knowledge of their reactivity ratios. Furthermore, we have shown that the processing and properties of these systems can be readily controlled by the proper combination...