SURFACE MODIFIED EXPANDED POLYTETRAFLUOROETHYLENE DEVICES AND METHODS OF PRODUCING THE SAME

• US 20090258960A1
• Filed: 06/04/2009
• Published: 10/15/2009
• Est. Priority Date: 08/05/1999
• Status: Active Grant

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: James Todd Walter
• Inventors: Walter, James Todd
• Granted Patent: US 7,736,576 B2
• Time in Patent Office: Days
• US Class Current: 522/2
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: D04H 1/54 by welding together the fibres, e.g. by partially melting or dissolving in combination with needling D04H1/485
• CPC Class Codes: D04H 5/00 Non woven fabrics formed of mixtures of relatively short fibres and yarns or like filamentary material of substantial length
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24372 Particulate matter
• CPC Class Codes: Y10T 428/24496 Foamed or cellular component
• CPC Class Codes: Y10T 428/2457 Parallel ribs and/or grooves
• CPC Class Codes: Y10T 428/24579 with particulate matter
• CPC Class Codes: Y10T 428/249964 Fibers of defined composition
• CPC Class Codes: Y10T 428/249978 Voids specified as micro
• CPC Class Codes: Y10T 428/8305 Miscellaneous [e.g., treated surfaces, etc.]

Abstract

Improved processes for surface treating expanded polytetrafluoroethylene (PTFE) is disclosed and improved surface-treated devices made from the processes. The processes employ a laser to surface-modify an expanded PTFE structure to create a macro-roughened surface that has the capability to remain microporous throughout. The unique process of the present invention creates a ridge and valley structure on the surfaces of devices that includes unique gnarled nodes along valley floors.

Claims

1. A continuous process for modifying a material surface, comprising the steps of:

a) providing an expanded polytetrafluoroethylene material having a surface comprised of nodes interconnected by fibrils, the fibrils having lengths;

b) exposing the expanded polytetrafluoroethylene surface to an unfocused laser beam to elongate fibrils and shorten fibrils to form node clusters;

c) exposing the polytetrafluoroethylene surface having said node clusters to an unfocused laser beam to remove the surface portion of some nodes and some elongated fibrils, thereby producing a material having said node clusters, valleys, and rough gnarled nodes connected by fibrils disposed on the valley floor; and

, next

d) exposing the material having said node clusters, valleys, and said rough gnarled nodes connected by fibrils, to an unfocused laser beam to remove the fibrils connecting said rough gnarled nodes to form gnarled nodes, said gnarled nodes having a protruding length and being substantially devoid of fibrils along the protruding length.

2. The process of claim 1 wherein the node clusters have a height and further comprises forming the gnarled nodes so that the protruding length of the gnarled node is greater than the height of the node clusters.

3. The process of claim 1 that further comprises forming a pattern of parallel groves in the surface.

4. The process of claim 1 that further comprises the unfocused laser beam having a width applied to the surface of between about 1.5 and 3 mm.

5. The process of claim 1 that further comprises providing a surface of expanded polytetrafluoroethylene comprising an implantable medical device.