CEH Report

Table of Contents

Abstract

This product review serves as a world overview of elastomer supply and demand; however, the various CEH marketing research reports and product reviews on each of the individual elastomers are the definitive source of data and information for each material.

The first section provides a world summary of natural and synthetic rubbers; the remaining sections cover the United States, Canada, Mexico, Brazil, Western Europe, Central and Eastern Europe, the Middle East, Japan, China, India, Republic of Korea, Taiwan and Other Asia. The report covers the following large-volume general-purpose elastomers—butyl, ethylene-propylene, nitrile, polybutadiene, polychloroprene (neoprene), polyisoprene and styrene-butadiene (SBR).

The following pie chart shows world consumption of synthetic elastomers:

Reclaimed rubber, which is made from ground scraps of both natural and synthetic rubber, is still an important raw material for compounding purposes. Vulcanized rubber scraps from used tires, inner tubes, shoes and hoses may be reused by industry after being reprocessed.

Although this overview does not cover specialty elastomers in detail, they are included in total elastomer production and consumption for individual countries, regions and world totals. Specialty elastomers fill an ever-growing demand for high-tech components for use in difficult environments that require resistance to heat, low temperature, high pressure, oxygen, ozone, weathering, oil, solvents and chemicals. The specialty elastomers include polyacrylic, chlorinated polyethylene, chlorosulfonated polyethylene, epichlorohydrin, fluoro- and silicone elastomers, polynorbornene, polysulfide, propylene oxide, transpoly-octenamer and vinyl acetate–ethylene elastomers. Although not typically thought of as specialty elastomers, polyurethane elastomers (excluding flexible and rigid foams) are included in this group for organization purposes.

In contrast to general-purpose elastomers, specialty elastomers offer one or more definite outstanding performance attributes, such as heat resistance, low-temperature flexibility, weatherability or chemical resistance. Specialty elastomers are generally relatively high in price and are used only in applications where their specific outstanding performance features are necessary to meet technically demanding design conditions; consequently, the volumes consumed are relatively small.

General-purpose and specialty elastomers constitute the thermoset elastomer family. Thermoset elastomers require heat for cross-linking (or vulcanization if sulfur is used as the cross-linking agent) the parts after extrusion or molding processes to fully develop their elastic properties. After cross-linking, thermoset elastomers develop unparalleled properties such as high resilience, low compression set, excellent abrasion resistance, good solvent resistance and deformation resistance at high temperature. Thus, thermosets still dominate the most critical applications such as tires, high voltage cables and seals.

Thermoplastic elastomers (TPEs) were developed to overcome the disadvantages of thermosets. TPEs can be processed like most plastics. They can be fed to the extruders or molding machines in pellets, do not require heat cross-linking and the scraps can be recycled. Although they do not possess the same critical properties as thermosets, TPEs have adequate softness and resilience for less critical applications such as adhesives, footwear, low voltage wire and cable insulation and polymer modification. Because of the fast cycle time, recyclability and overall cost-effectiveness, TPEs have become the fastest-growing of all major elastomer groups.

Thermoplastic polyolefins (TPOs) are essentially blends of a thermoplastic, such as polypropylene, and a soft polymer such as ethylene-propylene elastomer (EPDM) and/or a polyolefin elastomer. Ethylene-octene copolymers (polyolefin elastomers) made by metallocene catalysts have made inroads in replacing EPDM in TPOs. In TPOs, the soft polymer is dispersed in the thermoplastic matrix, but is not cross-linked. Also, in TPOs the elastomer is normally a minor component, constituting less than 30% in the blends, and the materials still feel more like plastics.