Exxon Research and Engineering Company

Exxon Chemical Patents, Inc.

Exxon Research & Engineering

Ronald C Kowalski

Neil F Newman

William M Davis

Francis P Baldwin

James V Fusco

Irwin J Gardner

Z Andrew Foroulis

Zisis A Foroulis

Gregory Mark Vero

Lewis Erwin

Brenton G Jones

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 process for cooling rubber crumb wherein the rubber crumb is presented for cooling to a first stage pneumatic conveyor containing a hot wet first stage air stream. The rubber crumb is cooled in the first stage pneumatic conveyor to a first temperature, whereupon the cooled rubber crumb is separated from the first stage air stream and transferred to a second stage air stream of cool dry air. A second stage pneumatic conveyor transports the rubber crumb in the second stage air stream for additional cooling.

Two-stage pneumatic conveying process for rubber cooling

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.

Extrusion drying of wet rubber crumb particles in the last phase of the overall elastomer drying process is improved through use of gas injected into the compression zone of an extruder thereby providing an improved efficiency in the explosion drying process. Rubber particles having a very low moisture content, such as less than 0.2% by weight, frequently less than 0.1%, are produced.

Elastomer extrusion drying with gas injection

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.

Process for the manufacture of halogenated elastomers

A continuous method for making free-flowing, melt-coated elastomeric pellets is disclosed in which pellets are coated with particles of coating material in a zone of interference created in a pneumatic conveying system.

Method for making free-flowing, melt-coated rubber pellets

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 five extruder-reactor zones under controlled conditions to achieve halogenation: feed, reaction, neutralization, wash and exit. 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.

Growing community of inventors

New Providence, NJ, United States of America

Ronald C Kowalski