Reclaim Plastic Scrap

Fig. 8-52 The addition of an extruded single plastic clamping strip at each side of a coextruded sheet permits scrap reclaim of the trim waste.

Thermoplastic elastomeric compositions from reclaimed NR and scrap LDPE with 50 50 mbber/plastic ratio shows good processability, ultimate elongation, and set properties. Polymer blends of reclaimed mbber and LDPE exhibit higher viscosity over the range of shear rate at various temperatures compared to virgin NR-LDPE blends due to the influence of filler present in the reclaimed mbber (Eigure 38.7) [109]. 

Worn-out tires and scraps and trimmings of other vulcanized products constitute the raw material for reclaimed rubber. Therefore a good reclaiming process must not only turn the rubber soft and plastic but also must remove reinforcing cords and fabrics that may be present. There are a number of commercial processes [43] for rubber regeneration (1) alkali digestion process, (2) neutral or zinc chloride digestion process, (3) heater or pan process, and (4) reclaimator process. 

Preconsumer plastic Plastic material diverted from the waste stream following an industrial process, but excluding reutilization of material such as rework, regrind, or scrap generated in a process and capable of being reclaimed within the same process. ... 

Filters. Many plastic materials—particularly reclaimed scrap—contain fines that can accumulate over time and blind the filters. If the filter fails and allows the fines to pass, they will contaminate the molecular sieve desiccant. Therefore, a dryer should be equipped with well-maintained filters on the return air line and on the regeneration air inlet. As a general rule, the process air filter will be the most critical because of the quantity of fines in the material being dried. But under dusty plant conditions, the regeneration filter is also important and must be maintained periodically. 

While many processes for using commingled plastics look at collection of bottles from curbside as the primary source of materials, they frequently combine these materials with industrial waste stream plastics, including coextruded scrap and other examples of multiresin, perhaps contaminated, materials. Other companies focus entirely on these types of waste streams. For example. Northern Telecom Ltd., based in Toronto, has a recycling facility for plastic reclaimed from wire and cable, along with materials from phone, fax, business machine, and pager equipment. The material, which contains small amounts of residual copper and aluminum, is used for truck mud flaps, flower pots, traffic stops, reflective bibs for construction workers, and other applications where high purity is not required,... 

Waste materials such as municipal solid waste, scrap tires, and waste plastics have traditionally been placed in sanitary landfills. However, with landfill space rapidly decreasing in the United States and worldwide, an alternative disposal method for these waste materials becomes imperative. The recycling of solid wastes is a challenging problem, with both economic and environmental constraints. Recently, two broad approaches have been attempted to reclaim solid wastes. The first approach relies on thermal or catalytic conversion of waste materials into fuel and valuable chemical feedstocks. Examples of this approach include gasification, pyrolysis, depolymerization, and liquefaction. The second approach relies on the physical recovery of valuable ingredients in the waste materials. 

Therefore, nowadays researchers pay more attention to reclaimed interpenetrating rubber. The main reason for this is the stable nature of IPNs in crosslinked rubbers and the strict specifications regarding the quality of products. The disposal problem of crosslinking rubber rejects and possible solutions are available. Another method to reuse large volumes of scrap IPN rejects is to use it as an impact plastic such as PS. 

As indicated in Chapter 1, global lead consumption from secondary sources approached four million tonnes per year in 2005, or 60 per cent of total world consumption. Around 20 per cent of world consumption is for uses where recycling is difficult, such as for plastics stabilisers, for TV tube glass, for shot and ammunition. Of the remainder, ten per cent is used for rolled or extruded alloys and cable sheathing, which have long-term applications, and 70 per cent is used for batteries. Recyclable lead therefore is predominantly from used automotive batteries, with some from reclaimed sheet, cable sheathing and other metallic scrap. In addition there are various residues, drosses and flue dusts containing lead. 

The methods of recycling depend very much on the type of the waste stream and the degree of cleanliness. The relatively clean PCW can be processed by similar methods as those used for industrial scrap. Numerous techniques have been developed for reclaiming the most readily identifiable constituents of such mixed waste streams as soft drink bottles (PET) and milk containers (HDPE). After separation of these containers, the remaining part of PCW (known as tailings) is made of PE s (50-75 wt%), styrenics (about 25 wt% of PS, ABS and their blends) and other plastics. These tailings can be cleaned, comminuted. 

Most processing plants have been reclaiming/recycling reprocessable TP materials such as molding flash, rejected product, film trim, scrap, and so on during the past century. TS plastics (not remeltable) have been granulated and used as filler materials. 

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