Composite products from carpets

Composite products from post-consumer carpet... 

This research on composite products from post-consumer carpet was supported by the State of Georgia s Traditional Industries Program (TIP), specifically the Consortium on Competitiveness of the Apparel, Carpet, and Textile Industries (CCACTI). The provision of carpet by Wellman, Inc. and glass mat by Eleison... 

Polymers from carpet waste produced by melt processing may be used to make products in a molding process, either alone or blended with virgin polymers. The recycled polymers may also be used as matrices in glass fiber reinforced composites. For such applications, the properties of the composites are dominated by the reinforcement (glass fibers), and therefore even recycled polymers without compatibilization could provide the composites with satisfactory mechanical properties. ... 

The use of PMDI as a binder for foimdry cores, rubber waste products, and solid rocket fuel are also known. Isocyanate-terminated prepolymers, often prepared from TDI or MDI with polyether polyols are also used as binders for composite products that require elastomeric properties. Athletic surfaces are sometimes prepared from groimd rubber tire scrap bonded with isocyanate-based prepolymers. Similarly, flexible polyurethane foam scrap is bonded with isocyanate prepolymers to form rebonded foam usefiil as carpet imderlay. Solidification of incineration ashes with PMDI-based binder systems is another waste disposal application. In this manner hazardous waste materials imdergo chemical fixation and detoxification. 

Another utilization of PA wastes originating from carpets is the application of face fibres and textiles as fibrous fillers for the manufacture of composites and laminates [52,53]. Ttimmed carpets were soaked with urea-formaldehyde resins, and subsequently pressed at 150-200°C and 3.4 MPa. The products are characterized by good mechanical properties (tensile modulus of 2.4-2.S GPa). 

United Recycling Inc. (URI), which was in operation from the early 1990s to 1999, introduced two extruded blends (URI 20-(X)l and URI 10-(X)1) from postconsumer carpet waste for injection molding in 1993 [61]. These were the first commercial recycled carpet compounds. The process used both polypropylene and nylon carpet. Their products were described as proprietary blends containing polypropylene. The composition and properties of the two compoimds are listed in Table 16.5. The molding compounds developed by URI were used to extrude carpet tack strip. 

Up to 25% by weight of the relatively pure recycled nylon is compounded with virgin nylon and reinforcements and is sold commercially as an injection molding resin. This resin with recycled content is not cheaper than virgin nylon due to the cost of separation and purification. While it is used to make engine manifolds, it is not sold in sufficient quantities to divert much carpet from landfills. Therefore, less pure and potentially less expensive composite materials and products based on post-consumer carpet are considered next. 

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