WO2013112938A1 - Reconfigured thermoplastic composite constructs - Google Patents

Abstract

Included herein are constructional techniques as well as finished goods produced thereby. Reconfigured thermoplastic composite constructs are described. The techniques are especially useful in connection with producing thermoplastic composite medical devices with unique traits and advantages.

Description

RECONFIGURED THERMOPLASTIC COMPOSITE CONSTRUCTS

RELATED APPLICATION

[0001 ] This filing claims the benefit of and/or priority to US Patent Application Serial

No. 61 /591 ,569 entitled, "Reconfigured Thermoplastic Composite Constructs," filed 27 January 2012 and incorporated herein by reference in its entirety.

BACKGROUND

[0002] The assignee hereof is in the business of developing products with fiber reinforced thermoplastic composites. The Plastiki boat was built employing an srPET (self-reinforced polyester fiber) composite frame securing approximately 12,000 two- liter bottles for buoyancy. The frame elements, together with the boat cabin, furniture, rudder and other structural features were all built from srPET.

[0003] The srPET material (e.g . , as supplied by Comfil, Inc.) comprises high melt (a high tenacity/reinforcement fiber component) and lower melt (a matrix material component) portions comingled with one another in tows woven into fabric. When heated to an appropriate temperature, the low-melt material flows to impregnate the solid-phase high melt material. Upon cooling, a fiber-reinforced composite member is produced in the desired shape.

[0004] Through the experience gained while proving the utility of srPET and further development of the same with the purpose of delivering environmentally friendly solutions in mind, the inventors hereof realized what further uses to which the material may be put. Namely, srPET and related fiber-reinforced thermoplastic polymer composites may be employed in the construction of medical devices as previously unknown.

[0005] Certainly, medical devices have been made employing thermoplastics in composite form. Specifically, catheters are commonly manufactured with

thermoplastic PEBAX material fused with metal braid to form a reinforced catheter. The PEBAX adheres the metal braid (often stainless steel or Nitinol), interior liner (often PTFE) and marker bands commonly employed in such construction.

[0006] A dramatically different approach to medical device construction is taught herein. It may be used to construct improved variations of known devices or altogether new devices with such advantages as described below and as will be further appreciated by those with skill in the art upon review of the subject disclosure.

SUMMARY [0007] Reconfigured thermoplastic composite constructs are described. According to the present invention, a woven, knitted or braided fabric comprising comingled thermoplastic fibers is provided. The fabric may comprise comingled srPET (i.e., a combination of high melt and low melt PET) another option is comingled PEEK and PET tow from which the fabric is made. Alternatively, the material may comprise a combination of a polymer (e.g., PET, PEEK, nylon, polypropylene, polyethylene) fiber and metal (e.g., stainless steel, Nitinol) fine wire (e.g., from about 0.0008 to about 0.002 inch diameter round wire or ribbon with comparable cross-sectional area and/or bending modulus).

[0008] The material may be combined within each tow as comingled material. The different materials may be in different/separate tows that are twisted together and woven, knitted or braided together. Alternatively, separate-material tows may by be woven, knitted or braided in a pattern together (optionally spooled together or by other means). Yet another option is coating the reinforcing fiber (metal or polymer) with the matrix material that will flow upon heating to consolidate a composite structure.

[0009] For use in medical device construction, the material selected should be

biocompatible. In any case, the starting "fabric" material is defined as a construct with a repeating or regular pattern holding tow in place. In the invention, a portion of the fabric is reconfigured/reorganized and formed into an different operative structure.

[0010] According to one example, a braided tube of fabric is provided. Before

heating (optionally in a pressurized mold) what will become a distal end of the medical device is de-braided/unbraided. The fibers thus-freed from the fabric structure can be manipulated and formed.

[0011] All of the fabric and the freed fibers may consolidated at the same time

without configuring the freed fibers into a final configuration. Rather, the freed fibers and the fabric can be consolidated in an intermediate step or transitional state of production.

[0012] In such an approach, the braided tube becomes a reinforced shaft and the unbraided fibers may be set into straight or curved beams. These beams can then be woven, knotted, crocheted, knitted or otherwise combined.

[0013] One such combination is in the form of a cage, basket or a temporary stent, examples of which are illustrated in: US Patent Publication Nos. 2009/0069828 and 2009/0299393 (Lazzarus Effect), USPN 5,916,235 (Target Therapeutics), USPNs 8,066,757; 8,070,791 or 8,088, 140 (Mind Frame) and US Patent Publication Nos. 2004/0068314 or 2008/0039930 (Johnson & Johnson) or as in the eV3 SOLITAIRE stent stentriever. Once so-configured, the structure (optionally held upon tooling within a complimentary mold cavity) is heated, causing the matrix material to flow and set its final shape upon cooling (i.e., it is heat set).

[0014] So-produced, truly "seamless" medical devices are formed. The wall of the catheter transitions from the pusher section to the active/working distal end of the device. This approach permits tremendous design flexibility. It avoids the weakness and/or bulk of joints or transitions. In a catheter-type design, it maintains maximum available lumen for a given outer diameter. Thus, miniaturization is also optionally served. This miniaturization may be in overall crossing profile, in catheter/sleeve wall thickness or otherwise.

[0015] The aforementioned beams may be fully consolidated. Alternatively they may be consolidated in sections, with sections only partially consolidated or left unconsolidated. Such locations can serve as hinge points. When fully unconsolidated (i.e., as in essentially virgin/fiber state) the fibers can be run-through as "eyelets" or crossing-points. Selective consolidation can be accomplished with a patterned heated "iron", ultrasonic weld head(s) or otherwise.

[0016] In another approach, a tubular form of fabric is provided. This material may comprise braid, rolled weave or knitted material, for example. A distal end of the device is reconfigured by passing pins or rods through the fabric, displacing fibers and rearranging their position but not cutting or punching through them. So-prepared, upon consolidation an infusion catheter can be produced. It will include composite walls that are, in fact, reinforced around the openings/ports in the device.

[0017] In still another approach, individual thermoplastic composite tows are

consolidated. Doing so greatly eases/facilitates their handling because they can otherwise fray, tangle or de-bundle. The tows may be consolidated as straight rods or "sticks". In another approach, they are consolidated as pre-shaped subcomponents.

[0018] Whether pre-shaped or not, they are then combined in a new configuration and then consolidated or simply bonded by heating and allowing matrix material therein to completely or selectively fuse/weld the elements together. When unshaped (i.e., straight) the subcomponents are typically reshaped at the working end of the device and reset in shape. If pre-shaped, the second consolidation may simply fuse/weld and finalize the construction.

[0019] The present invention includes such features as described above in any

combination of the options described. Aspects of the invention include methods of manufacture, the completed devices themselves and the devices in intermediate stages of manufacture. Still further, aspects of the present invention includes methods associated with and/or activities implicit to the use of the devices described.

BRIEF DESCRIPTION OF THE FIGURES

The figures provided herein are not necessarily drawn to scale, with some components and features possibly being exaggerated for clarity. Each of the figures diagrammatically illustrates aspects of the invention. Variation of the invention from the embodiments pictured is, of course, contemplated. Moreover, details commonly understood by those with skill in the art may be omitted from the figures.

[0020] Fig. 1 A illustrates a braided tube of thermoplastic composite material; Fig . 1 B shows the material in Fig. 1 A with one end reconfigured; Fig. 1 C shows tooling for use in consolidating the material in a second reconfigured state; and Fig. 1 D shows a final medical device product so-consolidated.

[0021 ] Fig. 2 is a flow chart illustrating the process of medical device production according to Figs. 1 A-1 D.

[0022] Figs. 3A and 3B illustrates the working end of another medical device during and after production.

[0023] Figs. 4A and 4B illustrate individual perform elements of consolidated tow.

[0024] Fig. 5 illustrates the Fig. 4A and/or 4B elements assembled and consolidated in a final medical device construction in the form of a guide wire.

DETAILED DESCRIPTION

[0025] Fig. 1 A illustrates a braided tube 10 of thermoplastic composite material. It includes interlaced tows 12 of thermoplastic composite material. The braid may have any number of such "ends" often provided in common multiples of 32, 48, 64, 72, 96, 144, 192 or 288 corresponding to even and half-loads of carriers on a given braider. Fig. 1 B shows the tube 100' in Fig. 1 A with one side reconfigured delacing the individual tows 102 to provide free tow ends 14.

[0026] Fig. 1 C shows tooling 20 for use in consolidating the material in a second reconfigured state. A form 22 may be provided with grooves, slots 24 or pins (not shown) in which (or around which) to set the freed tows 14 in configuring the shape of a working end of a medical device. The tows (alone or grouped with others) may be secured in place using adhesive (e.g. , 4014 LOCTITE), selective application of heat (e.g. , with an ultrasonic head or soldering iron) or slipped into spring-loaded locks (not shown, but otherwise resembling suture locks). An inner lumen within the braid may be maintained by inserting a mandrel 24 therein. At which point, the construct (braid, reconfigured tow and internal tooling) is set within a two-piece mold 26, 28. Various of the tooling elements may comprise stainless steel, or silicone rubber - the latter to facilitate pressure by expansion upon heating and release upon device cooling and being set in final shape.

[0027] Fig. 1 D shows a medical device 30 so-formed. It includes an (optionally

hollow) catheter or pusher shaft 32 and a working end 34 in the form of a temporary stent with struts 36. Marker bands or sleeves 38 (e.g. Pt or Ptlr) are optionally affixed on thermoplastic composite extension underlying the same. The affixation may be accomplished by local re-heating and flowing of matrix material within the composite tow, by adhesive, crimping or otherwise.

[0028] Fig. 2 is a flow chart 50 illustrating the process of medical device production according to Figs. 1 A-1 D and/or other options. Processing of such a device may occur by a direct path vertically down the flowchart or with optional "shortcuts" as indicated by

alternative paths X, Y and Z.

[0029] Taking each such path eliminates various acts as illustrated. However,

processing maybe more challenging given that organization/consolidation elements are then missing from the process flow. These processes may be employed in connection with such tooling above and/or vertical or horizontal shrink equipment such as available through Beahm Designs, Inc. otherwise using conventional catheter construction techniques. In any case, in the present context the referenced "heat setting" comprises heating at least a portion of the material causing the thermoplastic polymer matrix material to flow (typically without also flowing the material used in any polymer reinforcement filaments/fibers) and then cooling the thermoplastic polymer to set the device in the reconfigured shape.

[0030] Figs. 3A and 3B illustrates the working end of another medical device during and after production. In Fig. 3A, a tube 60 of fabric 62 is provided. It is set over a mandrel 64 (shown exposed by cutaway of the thermoplastic composite fiber tube for illustration only) with a plurality of pins or rods 66 passing through the fabric

(optionally the mandrel as well), displacing fibers 68 and rearranging their position somewhat as shown in Detail A. In Detail A, it is apparent how openings may be formed in the fabric and set in shape, without otherwise damaging the native material. Upon heat setting the complex (i.e. tube/mandrel/pins) within

complementary external mold element(s) and/or heat shrink and heating causing the matrix material to flow from/within the fibers gaps close as empty/void space is filled and an imperforate (except for the holes intended by pin placement) is completed as shown in Fig. 3B.

[0031] Fig. 3B provides an overview of an infusion catheter 70 so-constructed. A proximal body 72 is imperforate up to hub 74. A distal perfusion section 76 includes a plurality of holes or ports 78 therein provided as discussed above.

[0032] Figs. 4A and 4B illustrate individual perform elements 80 of consolidated tow.

These may be consolidated as straight rods or "sticks" 82 as shown in Fig. 4A. Such an approach may offer the advantage of in-line processing. Alternatively, the preforms may be more complex as in "corkscrew" end shaped elements 84 as shown in Fig. 4B. The elements in Fig. 4B may be produced substantially as described above, using a form around which to wind turns 86 and a cavity to receive elongate portions 88.

[0033] Another alternative is to reshape consolidated rods 82 into shaped elements

84. Either way, the members 82/84 can be combined for form a medical device - in this case in the form of a guidewire 90 as illustrated in Fig. 5. Here, the guidewire comprises multiple sections defining different flex zones as common in the art. In a fused (as indicated by stippling) proximal section 92 maximum stiffness is provided by the combination of linear element orientation and monolithic construction. In a more distal non/unfused section 94 greater flexibility is achieved since the elongate elements can flex independently. In a distal-most shaft section 96 the elements are arranged in a multi-filar helical cable arrangement. The turns 86, 86', etc. may be fused together at a distal atraumatic tip 98 or at strategic and varied locations along their length. The same holds true for section 94 (so as to make it a partially-fused section irrespective of the discussion above).

[0034] A straight or tapered core member 100 (optionally taper-ground NiTi,

stainless steel, CoCr or other metal alloy) can be fused or "float" within a central lumen defined by the partially (or fully) fused elements. The core member may be a mandrel over which the members are place for heat setting. Radio Frequency (RF) energy applied to the core member may be used to cause the heating. If any such core member/mandrel is used, it may be replaced with a different core member engineered (e.g., by taper grinding as typical in guidewire construction) for the desired flex performance of the final device. [0035] VARIATIONS

[0036] It is contemplated that any optional feature of the inventive variations

described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there is a plurality of the same items present. More specifically, as used herein and in the appended claims, the singular forms "a," "an," "said," and "the" include plural referents unless specifically stated otherwise. In other words, use of the articles allow for "at least one" of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only" and the like in connection with the recitation of claim elements, or use of a "negative" limitation.

[0037] Without the use of such exclusive terminology, the term "comprising" in the claims shall allow for the inclusion of any additional element irrespective of whether a given number of elements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set forth in the claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.

[0038] The breadth of the present invention is not to be limited to the examples

provided and/or the subject specification, but rather only by the scope of the claim language. Use of the term "invention" herein is not intended to limit the scope of the claims in any manner. Rather it should be recognized that the "invention" includes the many variations explicitly or implicitly described herein, including those variations that would be obvious to one of ordinary skill in the art upon reading the present specification. Further, it is not intended that any section or subsection of this specification (e.g., the Summary, Detailed Description, Abstract, Field of the

Invention, etc.) be accorded special significance in describing the invention relative to another or the claims. Any of the teachings presented in one section, may be applied to and/or incorporated in another. The same holds true for the teaching of any of the related applications with respect to any section of the present disclosure. These related applications are:

Low Weight Reinforced Thermoplastic Composite Goods (US 61/752,824);

Topo-Slice Thermoplastic Composite Components and Products (PCT/US 12/23031 ); Panel-Derived Thermoplastic Composite Components and Products (PCT/US 12/23022) ;

Thermoplastic Structures Designed for Welded Assembly

(PCT/US 12/23014); and

Hybrid Thermoplastic Composite Goods (PCT/US 12/23009),

each to the assignee hereof. Moreover, each and every one of these applications is incorporated by reference herein in its entirety for any and all purposes, as are all of the other references cited herein. Should any US published patent application or US patent claim priority to and include the teachings of one or more of the

aforementioned US provisional applications, then that US published patent application and that US patent is likewise incorporated by reference herein to the extent it conveys those same teachings. The assignee reserves the right to amend this disclosure to recite those publications or patents by name. And although the foregoing invention embodiments have been described in detail for purposes of clarity of understanding, it is contemplated that modifications may be practiced within the scope of the claims to be made.

Claims

1. A medical device made by a method comprising:

providing a body comprising an organized structure of filaments comprising a thermoplastic polymer;

maintaining a first portion of the body in its organized structure and reconfiguring a second portion into another, reconfigured working configuration; and

heating at least the second portion causing the thermoplastic polymer to flow and cooling the thermoplastic polymer to set the device in the reconfigured shape, whereby the device is heat set.

2. The medical device, wherein the first portion and the second portion are heat set simultaneously.

3. The medical device, wherein the second portion is heat set in an intermediate configuration before reconfiguring in the working configuration.

4. The medical device wherein the working configuration is in the form of a basket or stent.

5. The medical device wherein the working configuration is in the form of a perfusion section of a catheter.

6. The medical device wherein the body is a tubular braided body and the filaments comprise comingled matrix and reinforcement fibers.

7. A medical device made by a method comprising:

providing a plurality of elongate composite elements comprising a thermoplastic polymer matrix and reinforcement fibers;

reconfiguring the elements into a working arrangement, and

heat setting the arrangement to flow the matrix and bond the elements together.

8. The medical device of claim 7, wherein the thermoplastic composite elements are consolidated prior to the reconfiguring.

9. The medical device of claim 8, wherein the consolidated elements are shaped straight.

10. The medical device of claim 8, wherein the consolidated elements are shaped in the form of subcomponents in the working arrangement without further shaping.

11. The medical device of claim 10, where the medical device is a guidewire.