Laminated base, calendering

Multilayer co-extrusion is another technique used in the preparation of starch/ synthetic sheets or films [164, 263-266], in which TPS is laminated with appropriate biodegradable polymers to improve the mechanical, water-resistance and gas-barrier properties of final products. These products have shown potential for applications such as food packaging and disposable product manufacture. Three-layer co-extrusion is most often practiced, in which a co-extrusion line consists of two single-screw extruders (one for the inner starch layer and the other for the outer polymer layers) a feedblock a coat-hanger-type sheet die and a three-roll calendering system [164]. Biodegradable polyesters such as PCL [164, 264], PLA [164, 263], and polyesteramide, PBSA and poly(hydroxybutyrate-co-valerate) [164] are often used for the outer layers. These new blends and composites are extending the utilization of starch-based materials into new value-added products. 

Laminated fabric Fabric composed of a high-strength reinforcing scrim or base fabric between two plies of flexible thermoplastic film. Usually open scrims are used to permit the polymer to flow through the interstices and bond during calendering. 

White pigmented, lightly filled PVC sheet was made by dryblending 100 phr of PVC resin (K= 70) with 50-60 phr of plasticizer (as indicated. Table 3), 5 phr of surface treated TiOa, 10 phr CaC03, 0.3 phr of HALS/UV absorber UV package, 2.5 phr Ca Zn heat stabilizer and 0.25 phr stearic acid. Dryblends were extruded onto a calender and processed into 0.3 or 0.5 mm sheets. Sheets of different gauge were laminated around a polyester scrim, L9P based sheet on L9P based sheet, DIDP on DIDP and L9P/DIDP on L9P/DIDP. 

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