Structural Foam Extrusion

Material Family Injection Compression Hansfer Casting Cold Molding Coating Structural Foam Extrusion Laminating Sheet Forming RP Molding FRP Filament Dip and Slush Blow Rotational... 

Spectratech FM. [Quantum/USI] EVA, LDPE, or PS foam cones. for structural foam, extrusion, inj. moldings, wire and cable, blown film, business machine housings. 

Chem. Descrip. Modified azodicarbonamide CAS 123-77-3 EINECS/ELINCS 204-650-8 Uses Chemical blowing agent for cellular vinyl for plasticized vinyl, inj. molding structural foam, extrusion applies. food-contact coatings, rul> ber articles, closures with sealing ga ets for food containers Features Flow-treated dispersible free-flowing for Hopper blender units produces blown vinyl prod, with fine uniform cell structure eliminates settling problems... 

Fluorocarbon Blowing Agent n A family of inert, noncorrosive liquid compounds containing carbon, chlorine and fluorine, originally developed as refrigerants. They are compatible with all resins and leave no residues in molds. For years they were widely used in structural-foam extrusion, in which they were incorporated with the polymer by direct injection through the barrel of the first of two tandem extruders. Fluorinated... 

PBT-PC blends show increased melt strength allowing them to be easily processed by blow molding and profile extrusion. The PBT-PC blends have been extruded into sheet and thermoformed into parts. Enhanced melt strength allows PBT-PC blends to be foamed. Structural foam grades for injection molding (10-30% density reduction) are commercially available. 

All the molten-state methods are usable extrusion, injection, compression, blown film, blow moulding, thermoforming, structural foam, co-extrusion, machining for high hardness grades, welding. 

All the molten-state processing methods are usable extrusion, injection, blowing, compression, thermoforming, co-injection, machining, welding. Specific grades can be used for structural foam. 

Foam extrusion experiments are performed to study the effects of surrounding temperature variation on cell structure. LLDPE is used with endothermic chemical blowing agent on a single-screw extruder to exit from a capillary die into environments with different... 

Structural Foams. Structural foams are usually produced as fabricated articles in injection molding or extrusion processes. The optimum product and process match differs for each fabricated article, so there are no standard commercial products for one to characterize. Rather there are a number of foams with varying properties. The properties of typical structural foams of different compositions are reported in Table 4. The most important structural variables are again polymer composition, density, and cell size and shape. 

Ultem PEI resins are amber and amorphous, with heat-distortion temperatures similar to polyethersulfone resins. Ultem resins exhibit high modulus and are stiff yet ductile. Light transmission is low. In spite of the high use temperature, they are processible by injection molding, structural foam molding, or extrusion techniques at moderate pressures between 340 and 425°C. They are inherently flame retardant and generate little smoke dimensional stabilities are excellent. Large flat parts such as circuit boards or hard disks for computers can be injection-molded to maintain critical dimensions. 

Recycled PVC supermarket trays have been used successfully in production-scale trials to make the foamed layer in coextruded cladding. The extruded product had satisfactory foam density, foam structure and colour. Impact properties were better than those of the control made from virgin PVC this is attributed to the high levels of impact modifier used in tray formulations. These trials demonstrated that PVC straight-on trays can be recycled into foamed extrusions for wood replacement products. 8 refs. 

Whereas all conventional thermoplastic fabrication techniques have been successfully employed to convert pellets of HIPS into useful articles, extrusion (film, sheet, profile and multi-layer) and injection molding (solid, structural foam and gas-assist) are the predominant processing technologies. Innovative hardware technologies, in both extrusion and injection molding, have provided means to combine less expensive materials, such as polystyrene, with polymers or structures offering key performance characteristics. 

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