Shrinkable film and tubing

Shrinkablefilm and tubing Cross linked semicrystalline thermoplastics display rubberlike properties at temperatures above their melting points. On deformation followed by fast cooling the polymer maintains its deformed shape. The polymer returns to its original shape when reheated. This memory effect is applied in the production of heat shrinkable films and tubing. Radiation doses of the order of 40 — 1(X) kGy are used in the production of heat shrinkable products. 

Semicrystalline polyethylenes cross-link only in the amorphous regions. After sufficient cross-linking, the polymer does not flow any more. Typical polymers that can be cross-linked similarly are polypropylene, polystyrene, poly acrylates, and poly(vinyl chloride). Uses of the cross-linked polymer include wire and cable insulation, heat-shrinkable films and tubing. 

ICT machines produced recently have energy ratings from 0.3 to 3.0 MeV and beam power capabilities up to 100 kW. Nearly 180 of these machines, the majority of them rated for less than 1 MeV, have been installed as of the early 1990s. They are used mainly for cross-linking of heat-shrinkable film, plastic tubing, and electric wire. ... 

Cross-linking of wire and cables, heat shrinkable polymeric tubes and films, and PE foam. 

The film can then be fiattened and wound up as a tube or slit to obtain a single sheet. A polyvinylidene chloride film obtained in this way is heat-shrinkable at temperatures above SO C. If a heat-stabilised film is desired, an annealing step is applied by re-inffating the film and leading it through a radiant-heating tunnel (d). The third set of nip rolls (c) rotates at the same rate as the second set, and the air pressure in the bubble prevents the film from shrinking in the transverse direction. This is very effective... 

Plastic Film, Polyester, Polyethylene Coated (For I.D. Cards) Plastic Tubes and Tubing, Heavy Wall, Teflon TFE Resin Thermoset Epoxy Resin Sheet, Paper Reinforced Insulation Tape, Electrical, Pressure Sensitive, Telfon TFE Resin Plastic Material for Molding and Extrusion, High Density Polyethylene and Copolymers Insulation Sleeving, Electrical, Flexible, Heat-Shrinkable Film Tape, Pressure Sensitive Plastic Sheets, Virgin and Borated Polyethylene Insulation Tape, Electrical, High Temperature, Teflon, Pressure Sensitive... 

Manufactured PVDF parts can be cross-linked using high energy radiation to produce high temperature wire insulation, and heat-shrinkable tubing or film. 

Over the last few decades, the use of radiation sources for industrial applications has been widespread. The areas of radiation applications are as follows (i) Wires and cables (ii) heat shrinkable tubes and films (iii) polymeric foam (iv) coating on wooden panels (v) coating on thin film-video/audio tapes (vi) printing and lithography (vii) degradation of polymers (viii) irradiation of diamonds (ix) vulcanization of mbber and rubber latex (x) grain irradiation. 

Heat-shrinkable sheets (thickness 0.040 to 0.120 in., or 1-3 mm) and films (thickness 0.001 to 0.020 in., or 0.025 to 0.5 mm) are fabricated from many of the same materials as shrinkable tubing. They are produced by extrusion as a tube, sheet, or blown film. Irradiation is done by the equipment shown... 

Slot liners, for example, are used in motor and generator construction to separate and insulate coils of magnet wire from the slot walls in the steel stator, and films are also used to separate different coils of wire from one another (phase separation) in motors. For these applications, materials with good electrical, thermal, and mechanical properties are required. Special grades are applied in capacitors and heat-shrinkable tubing. 

Thermal shrinkage, accompanying release of moulded-in orientation, can be the cause of severe warping of pofymer mouldings when heated, but desirable effects can also be achieved. Shrink-wrap polymer films have caused a minor revolution in methods of packaging. Heat-shrinkable polymer tubes and cable insulation are currently finding wide application. 

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