Butylene Polymers

Published October 1971

This report is concerned with the technology and economics of producing butylene polymers, i.e., polybutenes, polybutene-l, butyl rubbers, and polyisobutylenes. Polybutene-2 and polycyclobutene also belong to the family of butylene polymers; however, these two polymers have been investigated only on a laboratory scale. Some discussion of the polymerization of butene-2 is included under chemistry.

In earlier literature and patents the difference between polybutenes and polyisobutylenes was not well defined. Technology, processes, products, and product applications for these polymers overlap one another in many instances, making a clear distinction difficult. In this report, the following definitions are followed:

• Polybutenes are the low molecular weight liquid obtained from polymerization of a refinery butane-butene stream.
• Polyisobutylenes are the polymerization products from a process using purified isobutylene feed.
• Butyl rubbers are the high molecular weight, vulcanizable co- polymers of isobutylene and isoprene.
• Polybutene-l is the high molecular weight, highly crystalline, isotactic polymer obtained from the polymerization of butene-l. Polybutene-l has also frequently been referred to as polybutylene in analogy to polyethylene and polypropylene.

A wide range of molecular weights and properties can be and is produced in some of the butylene polymers by varying the polymerization recipe. Cost estimates were based on selected recipes and were extra polated to other conditions whenever desirable and possible.