Roll-embossed film process

The tool used for roll embossing is a wheel or roller with built-in heating. The plastic molding follows a linear track as it passes underneath the tool on a conveyor belt, for example. By contrast with stroke embossing, the force is applied only locally, mapping the line of contact between roller with film and the blank. The ability to produce large, uninterrupted surfaces without air inclusions is one of the big advantages of this process [48]. 

Thermoplastic strnctnring of shell patterns on continnons films nsing a roller embossing process has been available indnstrially for several decades for fabrication of prodncts in varions applications, snch as diapers, packaging and raincoats [2, 8-10]. The roll embossing process, however, is designed towards the improvement of... 

Basically the calendering process is used in the production of plastic films and sheets. It converts plastic into a melt and then passes the pastelike mass through roll nips of a series of heated and rotating speed-controlled rolls into webs of specific thickness and width. The web may be polished or embossed, either rigid or flexible (9). One of its sheets major worldwide markets is in credit cards. At the low cost side these lines can start a million. A line, probably the largest in the world... 

US patent 4790815 (1988) to Baxter, Heat sterilizable plastic container with non-stick internal surfaces, describes the need to prevent sticking when two layers of plasticised PVC are left in contact during sterilisation. A texture of crosshatched lines is given to one surface of the film in the calendaring process, as a result of the surface of one steel roll being textured. If polyethylene blown film is used, texturing is achieved by the use of embossing rollers, but the polymer is less likely to block than plasticised PVC. 

---