Molding processes thermoforming

Thermoformed products are used in various outdoor and commercial applications which require tough products that have a large surface area. Typically, these products do not have close dimensional tolerances. Such applications include ornamental pool liners, dumpster lids, panels for portable sanitation facilities, and agricultural feed troughs. These products, which are not required in very large numbers, could not be produced economically by other molding processes,... 

PET plastics are hygroscopic so require proper drying before processing. They can be extruded, blow molded, and thermoformed on conventional equipment if dried to a moisture content of less than 50 ppm. Recycling all types of PET materials is easily accomplished. Of the 2002 total USA 49.4 million units of PET beverage container market 57% contain carbonated soft drinks and 24% contain water.485... 

The material can be processed through conventional techniques, such as extrusion (shaped profiles, foils, films, fibers), injection molding and thermoforming. 

Talc is always an attractive subject of such studies due to its platelet structure. In thermoforming and compression molding processes of three resins (PP, HDPE, and PPS), each containing 20% talc, the talc particles were always parallel to the specimen surface, regardless of the resin used. Crystallites grew in a direction normal to the surface of talc particles and thus were perpendicular to the specimen surface. But in the case of unfilled HDPE, crystallites grew parallel to the specimen surface. There was no difference in crystallite growth direction in the case of polypropylene with and without talc. 

Important processing methods injection molding, extrusion, thermoforming... 

Styrene Butadiene Copolymer Thermoplastic polymers of butadiene and >50% styrene having good transparency, toughness, and processibility. Processed by extrusion, injection and blow-molding, and thermoforming. Used in film wraps, disposable packaging, medical devices, toys, display racks, and office supplies. 

Styrenic Resins Styrenic resins are thermoplastics prepared by firee-radical polymerization of styrene alone or with other unsaturated monomers. The properties of styrenic resins vary widely with molecular structure, attaining the high performance level of engineering plastics. Processed by blow and injection molding, extrusion, thermoforming, film techniques, and structural foam molding. Used heavily for the manufacture of automotive parts. 

Furthermore, thermoforming is used to produce thin wall parts ectMiomically. The required force to deform a semi-finished product in the thermoforming process is reduced with decreasing thickness, while the shear force in the competing injection molding process increases. 

Both neat polyolefins and their blends and composites are commonly processed by blow molding, injection molding, extrusion, compression molding, rotational molding, and thermoforming. The final materials can be produced as bulk materials, fibers, and thin films. 

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