A technique for printing and embossing designs and decorations onto vinyl and other thermoplastic sheet and film is helping extrusion processors penetrate high-end cosnsumer durables by transforming commodities such as window blinds into designer products. Heat-transfer printing, which uses heat and pressure to lay decorations onto plastic parts, is now new, but is little used. Although decorated vinyl blinds remain niche they are high-margin items and have played a role in helping plastics reverse textile's once-dominated (80%) share of window treatment market over the last 15 years. The transfer method incorporates heat-transfer and laminating or embossing machinery that is positioned in the extrusion line shortly after the die. The designs are intially printed in-house onto coated release paper using a rotogravure press. The printed paper is wound onto feed rolls (which can be as wide as 63 in dia) that are mounted to the winding system of the transfer printing machine at the processor site. The processor can perform design and colour changes by switching feed rolls, thereby ensuring that there will be minimal downtime between part runs. The printing machine also consists of a metal nip roll and heated silicone roll. The silicone rolls, which operate at up to 360°F depending on the plastic, controls the traction and heat of the print-transfer process, while the metal nip roll controls pressure, temperature, and speed. In effect, the nip roller is turned into a printing press. Average process pressure is 5 psi. Maximum speed is 150 ft/min, though typical production speeds are around 80 ft/min. The transfers are reportedly precise to 0.003 in. And in some cases, the release paper can be reused as backing film for the end product as the prints are fully removed from the paper following the transfer. This can further increase the system's cost effectiveness. For three-dimensional textured designs, an embossing station is used to extorize a pattern onto one side of the product. The transfers are permanent and durable since they become part of the thermoplastic substrate.
Work is also being done to widen the scope of transfer technology beyond PVC. The process works with acrylic, polystryrene, and vinyl-coated aluminum.