ORTHOPAEDIC DEVICE

摘要

1517373 Laminated orthopedic devices YARDNEY CO 29 April 1975 [29 April 1974] 17794/75 Heading B5N A structure suitable for use as a formable orthopedic device comprises a plastics sheet having a thermally insulating layer on one side thereof, the plastics sheet being at least 50 mils thick and having a tensile strength at yield of 2,000-10,000 p.s.i., an elongation at yield of 3-30%, a flexural strength of 3,000-14,000 p.s.i., a flexural modulus of 0À5 x 105 to 7 x 105 p.s.i., a notched Izod of 0À3-30 foot pounds per inch, a Rolkwell harness of from 15 on the R scale to 55 on the D side and a Vicet softening point of 60-80‹ C., and the thermally insulating layer being at least 10 mils thick and having a coefficient of heat transfer of at most 2 cal/ sec./cm.2/cm/‹ C. x 10-4. The thermally insulating layer may be a woven, felted or knitted fabric made from aromatic polyamide fibres and/or high-temperature cross-linked phenolformaldehyde fibres. The plastics sheet may be made from a copolymer of vinyl chloride or diallyl maleate with ethylene or propylene and is preferably a composition comprising per 100 parts by weight of PVC, 10-14 parts of an impact modifier, e.g. methyl methacrylatebutadiene-styrene polymer and/or acrylonitrilebutadiene-styrene polymer, 1À25-2 parts of a lubricant, 7À5-8À5 parts of a plasticizer, 1À5- 2-1 parts of a processing aid, at least one stabilizer and at least one stabilizer booster compound, the total amount of stabilizer and stabilizer booster being 5À8-9À1 parts, and up to 5 parts of a pigment. The plastics sheet may be produced by extrusion or calendering. The plastics sheet may be bonded to the insulating layer using an adhesive, e.g. a polyurethane, extruded polyester, an acrylate, polyvinyl acetate or an ethylene/vinyl acetate copolymer, or by fusing. A protective fabric having a thickness of at least 4 mils may be bonded to the other surface of the plastics sheet using an adhesive, e.g. a polyurethane. The protective fabric, which may be knitted may be made from high temperature stabilized nylons, polyesters, polyurethanes, acrylics or cross-linked phenolformaldehyde fibres, cotton or wool. The fabric layers, which may have applied thereto extruded layers of polyester adhesive, may be bonded to the plastics sheet sequentially or simultaneously using a heated roll press or the plastics sheet may be extruded between the adhesive covered fabric layers. Cutting of the laminated structure to a desired shape may be facilitated by bonding a paper layer to one of the fabric layers using a pressure-sensitive adhesive, the paper being stripped off after cutting. An orthopedic device may be fitted to a part of the body by applying heat either to the plastics sheet or to the protective fabric layer when present, applying the heated structure to the body so that the insulating layer contacts the body, forming the structure to a desired contoured shape and allowing the structure to cool.