SCUP Report

Table of Contents

Abstract

Engineering polymers are capable of high performance in a variety of environments. Their greatest asset is a combination of high strength and light weight—characteristics that allow these high-value, specialty polymers to replace metals in many different applications. In the automotive industry, for example, reliance on lighter-weight engineering resins instead of heavier steel reduces fuel consumption. Other characteristics include high-temperature, corrosion and chemical resistance, as well as desirable electrical properties and design flexibility. Such qualities make engineering resins suitable for diverse applications, ranging from electronic systems and construction materials to medical products and consumer appliances. The largest markets for engineering polymers include automotive, electrical/electronic and industrial products. The primary use of ETPs as engineering materials is as molded parts and objects.

The engineering thermoplastic resin compounds discussed in this report include nylons, polycarbonate (PC), polyphenylene ether (PPE), polyesters, polyacetals and polyphenylene sulfide (PPS). The discussion focuses on the U.S., Western European, Japanese and Chinese markets.

Compounds can often be designed to meet a customer's needs better and/or less expensively than neat (uncompounded) resins or nonpolymer-based materials. Since compounds can be designed to have only the minimum properties required, the user does not have to purchase "overengineered" materials.

A variety of modifiers can be incorporated into plastics, including fibers, mineral fillers, reinforcements, impact modifiers and pigments. Engineering thermoplastics are sometimes blended. Blending one polymer with another can produce attractive alternatives to costly, overengineered plastics and inexpensive but underengineered materials. Alloys are special classes of blends that exhibit homogeneous structures and usually display properties superior to those of conventional blends. In most cases, specially designed compatibilizing agents must be added to the polymer blend to improve the miscibility of the polymers. This study includes a discussion of the major blends of ETPs and compatibilizing agents used to make commercial ETP blends.

The following graph shows consumption of engineering thermoplastics by type and region:

Transportation and electrical/electronic applications account for the majority of ETP consumption. The transportation market includes automotive, truck/bus, motorcycle, marine and aerospace applications. Consumption in this segment is driven largely by the automotive industry and represents approximately a 30–35% market share. The electrical/electronic market includes electromechanical (e.g., coils, bobbins, relays) and electronic components (e.g., connectors, sockets, switches), as well as business equipment housings (market share of 25%). Consumer end uses (with a 10% share) include lawn and garden equipment, power tools, office furniture, sporting goods, toys and miscellaneous products (e.g., pens, lighters, picture frames). Industrial applications (market share of 15%) include lighting/glazing, material and fluid handling equipment and plumbing/irrigation components.

Nylons are often reinforced with glass fibers and filled with minerals to increase dimensional stability (resistance to shrinkage after molding), strength, load bearing and temperature resistance. Mineral fillers, such as calcined clays and micas, are somewhat less effective than glass but are cheaper.

The most important polycarbonate blends are with either PBT or PET, both of which are used in automotive applications. PC/ABS blends are also widely used in electrical/electronic and automotive applications.

PPE is almost always blended with polystyrene or high-impact polystyrene (HIPS) to produce relatively low-cost polymers that have attractive properties. In recent years, however, PPE has been blended with nylon.

Polyesters are almost always reinforced with minerals, glass and carbon fibers to increase strength, stiffness, heat resistance and dimensional stability. The major polyester blends are those based on PBT/PET, PBT/ABS and PBT/PC.

Polyacetal homopolymer is reinforced with glass fibers to increase modulus (stiffness), strength and dimensional stability. Polyacetal is also sometimes blended with fluoropolymers such as poly(tetrafluoroethylene) (PTFE) to decrease the coefficient of friction and, thus, reduce material losses from abrasion.

PPS is generally reinforced with glass fibers or filled to reduce cost and modify its properties. PPS can be blended with PTFE to increase surface wear performance.

Environmental issues have become a significant concern for many producers and consumers of plastic materials. Solid waste disposal and the potential to reduce disposal through recycling are the major aspects of this concern. Although much of the focus of waste reduction and recycling of plastic materials is on packaging materials—which are largely polyolefins (HDPE) and PET—recycling of nylon and other ETPs is also practiced. The use of postconsumer engineering resin compounds, however, is limited by economics, including costs associated with collection and separation, and virgin resin prices. Some compounders are preparing for more recycling by acquiring recycling operations. Benefits include having a certified supply of recycled raw materials as well as increased knowledge about the markets these operations serve.