Polypropylene production, processing, uses

Patent Number US 6077878 A1 20000620 FOAM MADE FROM MODIFIED POLYPROPYLENE RESIN AND PROCESS FOR THE PRODUCTION THEREOF... 

Carpet waste generated each year and accumulated in landfills represents a considerable potential resource, as it may be converted into various useful products The rate of carpet disposal is about 2-3 million tons per year in the US A, and about 4-6 million tons per year worldwide. A carpet typically consists of two layers of (i) backing (usually fabrics from polypropylene tape yams), joined by CaCOj filled styrene-butadiene latex rubber (SBR), and (ii) face fibers (the majority being nylon 6 and nylon 66 textured yams) tufted into the primary backing. To use post-consumer carpet (PCC) as concrete or soil reinforcement, the carpet is shredded to recover fibers. It is generally not necessary to disassemble yams in the carpet into individual fibers. The size-reduction process yields the following from PCC ... 

Credit may be obtained from the recovery of polypropylene at 110 kg/t of lead produced. With a current value of US 1.30/kg the credit is worth 143/t of lead or 33 per cent of the direct processing costs, and will reduce the overall direct cost of refined lead to 490/t. This is clearly a most significant by-product. 

PLA is a transparent plastic whose characteristics resemble common petrochemical-based plastics such as polyethylene and polypropylene. It can be processed on equipment that already exists for the production of conventional plastics. PLA is produced firom the fermentation of starch from crops, most commonly com starch or sugarcane in the US, into lactic acid that is then polymerized. Its blends are used in a wide range of applications including computer and mobile phone casings, foil, biodegradable medical implants, moulds, tins, cups, bottles and other packaging [50]. 

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