PLASTICS RECYCLING

Status and Trends

Plastics are becoming an ever more important material in our society as their growth rate continues at an impressive rate. From 1960-1970, plastics consumption increased at an average annual rate of 11.8 percent, and totalled 8.5 million tons in 1969. Consumption by 1980 is expected to reach 19 million tons.20

Today, plastics account for only about 2 percent by weight of municipal solid waste and by 1980 will average about 3 percent. Very little plastic scrap is recycled other than that reused within the manufacturing plant in which it is generated. This, however, is a fairly significant quantity. Plastics fabricators, for example, consumed internal scrap equal to about 1.5 million tons in 1970.21 There is essentially no recovery of plastic waste from obsolete products.

The plastics reprocessor is the recycling channel for all industrial plastics recycled outside of originating plants. About 500,000 tons of waste plastics were handled by reprocessors in 1970. Of the plastics recycled through reprocessors about 55 percent came from resin producers, 30 percent from fabricators and 15 percent from converters.22

There are two types of plastics, thermoplastics and thermosetting plastics. The thermosetts-20 percent of plastics consumption cannot be softened and reshaped through heating and are thus not recyclable. In addition, most of the plastics used as coatings and adhesives are impossible to recycle. Thus, about 75 percent of the plastics consumed are potentially recyclable.

Sources and Markets

Table A-12 shows the major markets for plastics. Packaging and construction are by far the most significant, accounting for 20 and 25 percent respectively of consumption in 1970. Plastics from packaging account for about 60 percent by weight of the plastics in the solid waste stream (much of the other plastic consumed is "held-up" in permanent and semi-permanent end uses). Although some of the waste generated in the various stages of plastics production is recycled, the portion that is not makes up about 15% of the plastic in the waste stream. Thus, packaging and industrial waste account for 75% of plastic waste.23

As a general rule scrap plastic has to be used in an end application having wider specification requirements than the product

Source: Darnay, A., and W. E. Franklin. Salvage markets for materials in solid wastes. Washington, U.S. Government Printing Office, 1972. p.88-5.

yielding the scrap. The primary markets for scrap plastic include such items as hose, weather stripping, toys, cheap housewares, pipe, and similar applications where (1) plastic properties and performance are not paramount, (2) relatively noncritical processes are used (compression molding or heavy extrusion), and (3) where the cost of plastic resin is a high proportion of total product cost.

Plastics also have potential as a fuel supplement for energy generation due to their high BTU value of 11,500 BTU/lb. (The BTU content of paper is about 8,000 BTU/lb. and that of coal is about 12,000 BTU/lb.) This is particularly appealing for recovery of plastics (or value from plastics) in municipal waste, where plastics are hard to separate from other materials.

Issues and Problems

Technology. There is a fundamental difference between the nature of plastics recycling and that of metals, paper, glass, and other materials. Metals production, for example, begins with an impure ore which is progressively concentrated, smelted, refined and freed from impurities. Plastics production, on the other hand, begins with high purity virgin polymer to which various additives, colorants, and reinforcements are added. Thus, in the metals industries, there is a background of technology designed to purify and upgrade ores and concentrates. Such technology can also be applied to the upgrading of scrap. In the plastics industry, where the basic raw material is progressively "contaminated" in production, little technology has been developed which can be applied to purify waste plastics.

Compatibility. The principal difficulty in recycling plastics is that different polymers (polyethylene, polyvinyl chloride, etc.) are not compatible with each other and must be separated, a very difficult and costly task.

Economics. Continually decreasing cost of basic plastic materials has made scrap plastic less competitive with its main competitor, off-grade virgin resin. For example, since 1961, the price of low density polyethylene has decreased from 24 to 13 cents per pound. Scrap plastic, limited by rising labor and distribution costs, did not drop as rapidly, and the price of the scrap is now only about 1 cent per pound under the offgrade resin price, versus about 3 cents in 1961.

Logistics. This problem, common to recycling of all materials, is important to plastics recycling. The extremely low density of plastics makes transportation very costly.

Separation. Separation of plastics from other waste is extremely difficult, making recovery of plastics from municipal waste almost impossible unless the plastics can be diverted from the waste stream and kept separate.

TEXTILES RECYCLING

Status and Trends

The United States textile industry consumed approximately 5 million tons of textile fiber in 1970, an increase since 1960 of 61.5 percent. Far more significant to textile recycling was the change in the type of fiber consumed, with a major shift occurring from use of natural to man-made fibers. In 1960, natural fibers constituted 69 percent of fiber consumption, and man-made fiber 31 percent. In 1970, the figures were 39 percent for natural fibers and 61 percent for man-made. By 1980, the ratio of natural to man-made fiber is expected to be 25/75. The implications of this change are discussed below.24

In 1970, an estimated 0.8 million tons of waste textiles were processed by waste textile dealers and sold (recycled) to various markets.25 In addition, an undetermined amount of used clothing which potentially would enter the waste stream was collected by social welfare agencies and redistributed.

There are not sufficient historical data available to show trends in textile recycling. However, it is known that secondary textile consumption in many traditional markets has been declining and

that others such as the important wiping cloth market have been growing, at a slower rate than total textile consumption. Thus, it is almost certain that the rate of textile recovery (waste recovered vs. textile consumption) has been declining.

Textiles represent only a small portion of municipal solid waste. In 1968, textiles in collected municipal solid waste totalled 1.2 million tons, 0.6 percent of the total. Most of the textile consumption which does not appear in the municipal waste stream is either collected by social welfare agencies, disposed of or sent to secondary textile dealers by industry, or is being accumulated in households.

Sources and Markets

Fig. A-9 represents the major sources and markets for textile waste. The mill waste is the "home" scrap of the textile industry, the manufacturing waste the "prompt" portion and consumer discards "obsolete."

In contrast to most of the other materials discussed in this report, the "home" scrap (mill waste) is not reused within the generating plant, but instead passes through the secondary textile dealers. Mill waste accounted for about 1/3 of the material handled by waste textile dealers in 1970.

Waste from fabrication ("prompt") is a considerably less important source of recycled waste than in the case of many other materials. It has been estimated that waste recovered from fabrication is only about 60 percent of that generated.26 Fabrication waste accounted for an estimated 20 percent of the waste handled by waste textile dealers in 1970.

Obsolete waste accounted for the remaining 45 percent of recycled textile waste. The waste is provided mostly by social welfare agencies and institutions (such as Goodwill Industries) from items deemed unsuitable for reuse as clothing.

Issues and Problems

The increasing trend toward use of cotton-polyester blends and wool-polyester blends probably represents the major problem of textile recycling of the 1970's. These blends are not only generally unusable in themselves, but they tend to become mixed with other usable waste textiles and thereby reduce the economic value of the total waste supply. This has caused problems particularly in the three major markets for cotton waste: (1) rag paper, (2) vulcanized fiber, and (3) wiping cloths.