Exxon Research and Engineering Company

Exxon Chemical Patents, Inc.

Exxon Research & Engineering

Neil F Newman

Ronald C Kowalski

William M Davis

Francis P Baldwin

Irwin J Gardner

James V Fusco

Z Andrew Foroulis

Robert Roper

Zisis A Foroulis

David Y Chung

Donald A White

Ilan Duvdevani

Lawrence W Flatley

Pierre T Hous

Roger K West

Lewis Erwin

Tire curing bladders are made from poly(isobutylene-co-4-bromomethylstyrene) with a benzylic bromine content of from 0.15 to 0.45 mole percent, vulcanized with a cure system of 1,6-hexamethylene-bis(sodium thiosulfate) and zinc oxide. The vulcanizate has low residual benzylic bromine content which leads to enhanced stability under severe duty applications, reduced hot tension set, and reduced adhesion or co-cure to halobutyl tire innerliners.

Low bromine isobutylene-co-4-bromomethylstyrene compositions for severe

A process for halogenating a copolymer of a C.sub.4 to C.sub.7 isomonoolefin, e.g. isobutylene, and a multiolefin, e.g. isoprene or a para-alkylstyrene, e.g., para-methylstyrene, is disclosed. Increased halogenation efficiency and decreased reaction time is achieved by conducting the reaction in the presence of a halogen source and an aqueous emulsion containing a water soluble oxidizing agent, e.g. hydrogen peroxide, which oxidizes hydrogen halide generated in-situ in the reaction back to free halogen.

Process for halogenating isomonoolefin copolymers

A process for halogenating a copolymer of a C.sub.4 -C.sub.7 isomonoolefin, eg. isobutylene, and a para-alkylsyrene, e.g., para-methylstyrne, is disclosed. Increased halogenation efficiency is achieved by conducting the reaction under free radical halogenation conditions and in the presence of an oxidizing agent, e.g. hydrogen peroxide, which oxidizes hydrogen halide generated in-situ in the reaction back to free halogen. The oxidizing agent is preferably not added to the reaction medium until after first stage halogenation is substantially completed.

Process for halogenation of isomonoolefin/para-alkylstyrene copolymers

A process for halogenating copolymers of an isoolefin having from 4 to 7 carbon atoms and a para-alkylstyrene in the melt phase is provided in which the halogenation reaction is performed in a continuous flow device, such as an extruder-reactor. Halogenated copolymers produced by the process are also provided.

Process for halogenating para-alkyl styrene/isoolefin copolymers

A process for halogenating polymers by contacting a polymer either in solution or in bulk with a halogenating agent in the presence of an acid scavenger. Halogenated polymer, e.g., butyl rubber, with a particular structure is obtained and the product suffers less molecular weight loss. Combinations of acid scavengers can also be used and the scavenger can be dispersed in the polymer prior to halogenation and/or added to the reaction zone during halogenation.

Acid scavenged polymer halogenation

A halogenation process is provided for halogenating a polymer, in which process the halogenation reaction product is neutralized by reaction of an aqueous alkaline material in the presence of a critical limited amount of alcohol to increase the neutralization rate.

Halogenation of polymers with improved neutralization

An improved halogenated butyl rubber wherein the polymer has a conjugated diene content of less than 0.25 mole % and a halogen content of at least 0.6 wt. %; at least 20 mole % of the halogen being in a primary allylic configuration.

Halogenated butyl rubber

In a process for the continuous halogenation of polymers by contacting polymer and halogenating agent in a continuous flow device in which means are provided for disengaging reaction by-products and unreacted halogenating agent from the reaction mixture, by deforming and disrupting the halogenated polymer surface and injecting an inert and/or reactive gas into the halogenated polymers immediately after reaction thereby neutralizing the product. In a preferred embodiment the process is carried out in an extruder-reactor and an optional, supplementary inert and/or reactive gas scrubbing zone is included. The process is amenable to saturated and unsaturated polymers.

Process for the manufacture of halogenated polymers

A process for the continuous bromination of butyl rubber polymer by contacting the polymer with a brominating agent in a continuous flow device in which means are provided for disengaging reaction by-products and unreacted halogenating agents from the reaction mixture, by deforming and disrupting the brominated polymer surface and injecting a neutralizing agent into the polymer immediately after reaction thereby neutralizing the polymer, comprising contacting a polymer substantially free of acid scavengers, with the brominating agent at elevated temperatures the bromination reaction being carried out in an acid atmosphere, thereby producing a polymer having a substantial fraction of the bromine in the primary allylic position.

Extrusion process for preparing improved brominated butyl rubber

In a process for the continuous halogenation of polymers by contacting polymer and halogenating agent in a continuous flow device in which the polymer and halogenating agent are subjected to deformation during reaction and in which means are provided for disengaging reaction by-products and unreacted halogenating agent from the reaction mixture, a significant process improvement is realized by injecting an inert gas into the halogenated polymers immediately after reaction in order to neutralize the product. In a preferred embodiment the process is carried out in an extruder-reactor and an optional, supplementary inert gas scrubbing zone is included. The process is amenable to saturated and unsaturated polymers.

In a process for the continuous halogenation of polymers by contacting polymer and halogenating agent in a continuous flow device in which means are provided for disengaging reaction by-products and unreacted halogenating agent from the reaction mixture, by deforming and disrupting the halogenated polymer surface and injecting an inert gas into the halogenated polymers immediately after reaction thereby neutralizing the product. In a preferred embodiment the process is carried out in an extruder-reactor and an optional, supplementary inert gas scrubbing zone is included. The process is amenable to saturated and unsaturated polymers.

Continuous halogenation of polymers is achieved by contacting polymer and halogenating agent in a continuous flow device in which the reactants are present as either co-continuous phases or wherein the halogenating agent is present as a continuous phase and the polymer is present as a discontinuous phase, the polymer is subjected to deformation during reaction and in which means are provided for disengaging reaction by-products and unreacted halogenating agent from the reaction mixture. In a preferred embodiment the polymer passes through three extruder-reactor zones under controlled conditions to achieve halogenation: feed, reaction (preferably vented), neutralization, and optionally a wash and exit zone. A continuous halogenating agent phase is achieved during reaction by avoiding complete filling of the reaction zone with polymer. Various halogenated polymers are produced, for example, halogenated linear low density polyethylene and halogenated butyl rubber.

Continuous halogenation of polymers is achieved in an extruder-reactor employing reactants, conditions and design features directed to maximizing mixing and contact of the polymer with the halogenating agent and neutralizing agent while simultaneously minimizing side reactions and polymer degradation. The polymer passes through three extruder-reactor zones under controlled conditions to achieve halogenation: feed, reaction, neutralization, and optionally a wash and exit zone. Various halogenated polymers are produced, for example, halogenated linear low density polyethylene and halogenated butyl rubber.

Continuous halogenation of olefinically unsaturated rubber is achieved in an extruder-reactor employing reactants, conditions and design features directed to maximizing mixing and contact of the rubber with the halogenating agent and neutralizing agent while simultaneously minimizing side reactions and polymer degradation. The rubber passes through three extruder-reactor zones under controlled conditions to achieve halogenation: feed, reaction, and neutralization; optionally a wash and exit zone can be utilized. The halogenated rubber, for example, halogenated butyl rubber can be vulcanized in the absence of sulfur, e.g., with zinc oxide and stearic acid, and is useful in all applications where commercially available chlorinated and brominated rubbers are presently employed.

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Edison, NJ, United States of America

Neil F Newman