Cast film grades

The major usage of CAB and CP is in plastics. Additionally. CAB and CP are mixed with a variety of synthetic polymers to produce lacquers for wood, metal, and plastics. CAB finds relatively small usage in hnt-uielal coalings and in optical-grade cast film used in Lhe manufacture of sunglass lenses. 

All polyurethane materials used in this study were either in the form of extruded tubes (Tygothane, Superthane, Pellethane) or as films cast on clean glass from reagent grade dimethylacetamide (DMAC). Only the luminal surfaces of the tubes and the glassfacing sides of the cast films were observed by ESCA. 

Polymer Preparation. Poly (vinyl chloride). The PVC polymers were all commercial materials. Representative suspension grade PVC polymers are Goodyear s Pliovic K656 and K906 and Dow s 144. K656 (IV = 0.77) was used for the melt blends, and K906 (IV = 1.1) and 144 (IV = 1.0) were used for the solution-cast films. 

PP has inherent good barrier properties and high clarity, in addition to proper radiation resistance. Properties which made PP one of the best candidates in medical devices and packaging applications (parenteral nutrition and dialysis films, blister packaging and flexible pouches, syringes, tubing, hospital disposables, test tubes, beakers and pipettes). Medical grade PP is used mostly as blown, cast films and also as coextruded layered structures. 

Film Processing Methods The Selar PA resin can he processed hy the same blown film, cast film, or cast sheet equipment used with semicrystalline nylons or polyolefins. Selar PA nylon 6 blends can be made by dry-blending. Selar PA 2072 can be tumble-blended with most grades ofEVOH.t l... 

Material Supplier/Grade Dow Chemical Attane for Cast Film ... 

General Description Ticona Topas are amorphous, glass-clear copolymers of ethylene and norbomene. Ticona Topas cyclic olefin copolymers (COC) form strikingly clear films. When blended with polyethylene (PE), they enhance the stiffness and heat-seal behavior of blown and cast films and offer high moisture barrier, clarity, and stiflfiiess. The Tieona Topas product line features several grades differentiated by heat deflection temperatures ranging from 80° to 18o°c.[ioi5]... 

Material Supplier/Grade DuPont Elvax EVA Copolymers for Cast Film Applications... 

Uses Adhesive/sealant resin for use in blown and cast film extrusion applies, incl. meat/poultry/seafood/cheese pkg., cereal liners, medical/ pharmaceutical pkg., powd./granularfood and non-food pouches, carded display/skin packaging films edible oil, motor oil, other li prod, pouches, snack structures coextrusions with nylon or in other film structures as heat seal or tie layer Features High clarity grade Regulatory FDA 21 CFR 177.1330 compliant Properties Melt flow 1.5 dg/min f.p. 78 C m.p. 103 C Vicat soften, pt. 81 C ultimate tens. str. 33.1 MPa (MD) ultimate elong. 450% (MD) Spencer impact str. 29 J/mm Dart drop str. 7.9 g/pm Elmendorf tear str. 46.3 mN/pm 9% methacrylic acid... 

LLDPE can be drawn or stretched in the melt with low induced orientation (see Chapter 1), so a wide die gap does not add undesirable film stresses for LLDPE as with LDPE. The optimum die gap for each application will vary according to resin grade, melt heat, and output rates. Only the die mandrel requires modification for conversion to LLDPE. If only LLDPE is to be run, then the existing mandrel can be machined down. If both resins are to be run, two separate mandrels are required. As cast film is processed at considerably higher heats than blowm film, shear stresses are minimized, and no die modifications are required. 

Just as with most other polymers, processability is an important parameter to commercial success for biodegradable polymers. For example, some grades of starch-based polymers can be processed on standard low-density poly(ethylene) extension equipment for making blown or cast film. Other grades... 

Markets for cast film are (a) stretch film that is used in pallet wrapping and other types of shipping to secure the load, (b) high clarity films, and (c) more recently cast film is used in fabricating premium-grade trash bags. 

Figure 1. Partial transverse sections of intraperitoneal implants and surrounding tissues recovered after 105 days (A) Nation film solution-cast on thermally cured Nation sheet (the arrows identify the solution-cast film which has separated from the underlying Nation sheet substrate) (B) Medical Lnplant-Grade Silastic silicone rubber (tissue capsule only). The double-headed arrows correspond to 0.21 mm on original specimens. (Reproduced with permission from reference 13. Copyright 1991 Butterworth—Heinemann Ltd.)...

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