PTFE Foams
Polytetrafluoroethylene resins can be foamed into stable foam materials. (RDC 1/7/2011)
“In many medical and non-medical commercial uses, it is desirable to have PTFE in the form of a porous film that retains adequate physical strength for the particular application while not substantially increasing the cost of the material. Expanded PTFE (hereinafter "ePTFE") is a form of PTFE that has been physically expanded along one or more directions to create a porous form of PTFE having varying amounts of porosity depending on several factors including the specific procedures for performing the mechanical expansion. The porous ePTFE thus created is useful for the manufacture of several commercial products as illustrated (for example) by the work of Gore in U.S. Pat. Nos. 3,953,566 and 4,187,390 and the work of House et. al. in U.S. Pat. No. 6,048,484. Applications to stents include the work of Lewis et. al. (U.S. Pat. No. 5,993,489) and Bley et. al. (U.S. Pat. Nos. 5,674,241 and 5,968,070). The chemical inactivity, and other properties of fluorinated polymers including PTPE and ePTFE, have made them attractive substances for use in many medical and blood-contacting devices. Representative examples include dental implant devices (Scantlebury et. al. U.S. Pat. No. 4,531,916), grafts, stents and intraluminal prosthetic devices (Bley et. al. U.S. Pat. Nos. 5,674,241 and 5,968,070; Goldfarb et. al. U.S. Pat. No. 5,955,016; Lewis et. al. U.S. Pat. No. 5,993,489; Tu et. al. U.S. Pat. No. 6,090,134).”
“Expanded PTFE is widely used in medical devices and is perhaps one of the most widely used vascular graft materials. In fact, ePTFE has a large range of application in blood-contacting medical devices including, but not limited to, segmental venous replacements, reconstructed veins in organ transplantation, polymer catheters, in-dwelling catheters, urological and coronary stents, covered stents, heart valves, dental implants, orthopedic devices, vascular grafts, synthetic by-pass grafts and other invasive and implantable medical devices. In addition, ePTFE can be used in extra-corporal blood-contacting devices. Examples include, but are not limited to, heart by-pass devices, kidney dialysis equipment, blood oxygenators, defoaming machines, among others.”
Recent US Patents
10/5/2010
7,807,210
Hemocompatible polymers on hydrophobic porous polymers
Roorda, Niraj and Lundkvist of Advanced Cardiovascular Systems, California produced a blood compatible foam by expanding PTFE with heparin in combination with a hydrophobic counter ion. (RDC 12/20/2010)
7,807,066
Method of manufacturing a porous resin substrate having perforations and method of making a porous resin substrate including perforations having electrically conductive wall faces
Uenoyama et al of Sumitomo Electric Industries, Japan, formed a perforated fluoropolymer foam by perforating the foam mechanically and etching the holes by laser ablation and an alkali metal such as sodium, oxidizing the etched surface with hydrogen peroxide and coating the wall with a conductive plastic using a catalyst and plating solution. (RDC 12/20/2010)