POST-CONSUMER

Environmental Aspects. More than two-thirds of aluminum cans are recaptured and returned for recycling into more cans. Because of the heat of melting, the use of post-consumer recycled cans is safe for beverage contents. Not only does recycling save on mass of materials, it also saves the energy of manufacture from aluminum ore (see Recycling, nonferrous metals). 

Coalition ofJSlortheast Governors. The CONEG model heavy-metal guideline is implemented through state regulations and limits total metal content of lead, chromium, mercury, and cadmium. The limitation of 100 parts per million total is aimed at protecting the environment from the disposal of post-consumer waste. 

New plant constmction will bring iacreased capacity to a level which will depend on real growth to keep sales abreast with production. It is anticipated that consoHdation of ownership will continue and that the trend to specialized busiaesses supporting a plant faciUty will also continue. Pressures from environmental issues could change the cost of final products as well as mandate the use of post-consumer waste resia as feedstock for production. 

Recycling of HDPE. Polyolefins, including HDPE, are the second most widely recycled thermoplastic materials after PET (110). A significant fraction of articles made from HDPE (mostly bottles, containers, and film) are collected from consumers, sorted, cleaned, and reprocessed (110—113). Processing of post-consumer HDPE includes the same operations as those used for virgin resins blow mol ding, injection molding, and extmsion. 

The current and projected HDPE capacities are shown in Table 3, and producers of resins in Table 4. In most cases, an accurate estimation of the total HDPE volume is compHcated by the fact that a large number of plants also use the same reactors for manufacture of HDPE or LLDPE. UHMWPE is produced in the United States (Himont and American Hoechst), in Japan (Asahi), and in Germany (Hoechst) worldwide capacity is approximately 45,000 tons. The use of post-consumer (recycled) HDPE is gradually increasing in volume. The growth of recycling programs is driven principally by economics (110,114) it has increased from a mere 60,000 tons in 1989 to 350,000 tons in 1994 and is expected to increase to 1.4 million t in the year 2000 (115). 

Lewis acids, such as the haUde salts of the alkaline-earth metals, Cu(I), Cu(II), 2inc, Fe(III), aluminum, etc, are effective catalysts for this reaction (63). The ammonolysis of polyamides obtained from post-consumer waste has been used to cleave the polymer chain as the first step in a recycle process in which mixtures of nylon-6,6 and nylon-6 can be reconverted to diamine (64). The advantage of this approach Hes in the fact that both the adipamide [628-94-4] and 6-aminohexanoamide can be converted to hexarnethylenediarnine via their respective nitriles in a conventional two-step process in the presence of the diamine formed in the original ammonolysis reaction, thus avoiding a difficult and cosdy separation process. In addition, the mixture of nylon-6,6 and nylon-6 appears to react faster than does either polyamide alone. 

More often than not, however, the demand for post-consumer materials has failed to keep pace with this boom in collection. In many regions of the United States and elsewhere, the supply of recyclable materials is so great that cities have been forced to either store the materials or curtail the number of items collected. Many principal cities worldwide have reported occasions when source-separated materials were actually sent to dumps or incinerators rather than being recycled (4). 

The auto industry has estabbshed a cooperative program in the field, the Vehicle Recycling Partnership (VRP). In addition, some auto manufacturers have announced specific projects that include recycled mbber. Chrysler has announced that it is already using a mbber shield that incorporates cmmb mbber derived from scrap tires. Auto manufacturing companies have indicated a desire to expand the use of recycled post-consumer scrap mbber in their products. 

Vinyl is recycled by at least 170 recyclers in the United States and Canada. In 1994, about 2.9 x 10 t (6.5 x 10 lb) of post-consumer vinyl were recycled in the United States. An estimated additional 135 x 10 t (300 x 10 lb) of vinyl post-industdal scrap was diverted from landfills and recycled into second-generation products. More than 3500 communities accept vinyl products in their recycling programs, which is about 25% of all communities that recycle. 

There are many common misconceptions about vinyl. Eor example, the idea that vinyl is not recycled is untme. Industrial scrap vinyl has been recycled for years, but in more recent years, post-consumer vinyl recycling is growing, too, with about 3.25 x 10 tons (6.5 x 10 lb) of post-consumer vinyl (primarily botdes) being recycled in the 1990s. When the Council for SoHd Waste Solutions (now the American Plastics Council) conducted a nationwide survey in 1991, it found that there were an estimated 1100 municipal recycling programs in place or plaimed in the United States that include vinyl. 

Honeywell Plastics Nylon 6,6/6, (Recycled 6) PET (Post Consumer) ... 

APPR Assoc, of Post-consumer Plastics Recyclers... 

DuPont has recently announced plans to build a demonstration plant in Maitland, Ontario, to show that the quality of the recycled product is equivalent to the virgin material (64). BASF converts post-consumer carpet into caprolactam in Ontario. Rhodia has several European plants for depolymerising nylon 6. 

Commercial plastics polymerisation is akin to making pig s ears out of silk purses, albeit usually useful porcine ears from very worn out handbags. What were once valuable polymers are turned into generally less valuable monomers. The regenerated monomers and small chemicals from polymerisation of post-consumer plastics have no particular moral authority or intrinsic grace compared to chemicals derived from non-recycling sources. To be successful, commercial polymerisation must make economic sense in ways that are understood by those who invest dear money into capital assets. 

POST-CONSUMER PETP FROM PROBLEM TO OPPORTUNITY... 

Dicarboxylic acids or esters thereof are recovered from solid phase polyester materials, such as post-consumer products and factory scrap, by subjecting the polyester to at least two hydrolysis stages in at least the first of which the amount of water used is substantially less than needed to effect total conversion of the polyester to the dicarboxylic acid. Also the diol content is controlled in the course of carrying out the hydrolysis. The hydrolysis reactions may be preceded by reaction of the polyester with a diol, the resulting depolymerisation products then being hydrolysed. 

FIRST POLYAMIDE-6 FROM POST-CONSUMER RECYCLING... 

Post-consumer PMMA plastics can be depolymerised back into their starting components. Degradative extrusion in twin-screw extruders can be used for this process. 10 refs. Translation of Kunststoffe, 87, No.2, Feb.1997, p.183-8... 

Davos, 15th-19thMay 1995, paper 20. 8(13) FEEDSTOCK RECYCLING OE POST CONSUMER WASTE PLASTICS Niemann K... 

Post-consumer plastic waste recycling is discussed with special reference to feedstock recycling, the advantages it has over mechanical recycling, and the techniques involved. Chemolysis and thermolysis are explained, and... 

USE OF REFUSE DERIVED FUEL ENHANCED WITH POST-CONSUMER PLASTICS FOR THE PRODUCTION OF ELECTRICAL ENERGY BY THE GASIFICATION PROCESS... 

Results are presented of studies undertaken in Italy by SAFI and Replastic of the gasification of refuse derived fuel enriched with post-consumer plastics for the production of electrical energy and gas for use in cement making. 11 refs. 

---