Improved bend radius and reserve length in polyethylene constructs

Abstract

An article includes an expanded polyethylene substrate (12) having a longitudinal length, a first zone (14), and a second zone (16). The first region has a first density, the second region has a second density, the second density is greater than the first density, and the second region is imprinted.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 433,093, filed Dec. 16, 2022, which is hereby incorporated by reference in its entirety for all purposes. Technical Field

[0003] The present disclosure generally relates to apparatuses, systems, and methods for embossing expanded polyethylene. More specifically, the present disclosure relates to apparatuses, systems, and methods for embossing expanded polyethylene that can be used in medical devices. Background Art

[0004] The method of processing materials is as important as the method can endow the processed materials with specific qualities. The specific qualities may be necessary for the processed materials to achieve their intended purposes, or may allow the processed materials to be used in new ways. The choice of processing method is important in various industries, including but not limited to the medical device industry, and more specifically, it is important for implantable medical devices. However, the processed materials can be used in different industries, and the same properties desired in one industry may also be important in other industries.

[0005] Medical devices typically need to be adaptable to meet the needs of patients. For example, an implantable device made of a processed material may need to fit within a tortuous geometry or be adaptable to a tortuous geometry. To accommodate a tortuous geometry, the implantable device can be shaped or processed into different configurations. However, the processed materials can be subjected to stress during operation and may thus be prone to failure. There is a need for materials that can be used to provide medical devices that can operate without failure upon implantation. Summary of the Invention

[0006] The present disclosure relates to a method for densifying expanded polyethylene and articles produced by the method of densifying expanded polyethylene. For example, the method and articles produced by the method include: selectively densifying some portions of an expanded polyethylene substrate to produce a stored length. This can result in desired characteristics such as an increased bend radius, torsional tolerance, and durability, among others.

[0007] According to one example (“Example 1”), the article comprises an expanded polyethylene substrate having a longitudinal length, having a first zone and a second zone, wherein the first zone has a first density and the second zone has a second density, the second density being greater than the first density, and wherein the second zone is embossed.

[0008] According to a further another example based on Example 1 (“Example 2”), at least one of the expanded polyethylene substrates is longitudinally or laterally compressed, defining a reserve length along at least a portion of the longitudinal length.

[0009] According to a further another example based on Example 1 (“Example 3”), the expanded polyethylene substrate is a tubular member.

[0010] According to a further another example based on Example 3 (“Example 4”), the second zone is a ring extending around the tubular member at a longitudinal position defined along the longitudinal length.

[0011] According to a further another example based on Example 4 (“Example 5”), the second zone includes: a plurality of rings extending around the tubular member at a plurality of longitudinal positions defined along the longitudinal length.

[0012] According to a further another example based on Example 1 (“Example 6”), the expanded polyethylene substrate does not contain an adhesive.

[0013] According to a further another example based on Example 1 (“Example 7”), the expanded polyethylene substrate includes a plurality of expanded polyethylene layers connected together.

[0014] According to an example (“Example 8”), a method of forming an article includes: optionally, providing an expanded polyethylene substrate having a first density, selectively densifying a portion of the expanded polyethylene substrate to form one or more densified portions of the expanded polyethylene substrate, wherein the expanded polyethylene substrate has one or more undensified portions having the first density, and wherein the one or more densified portions have a second density greater than the first density, and wherein the one or more densified portions are disposed adjacent to the one or more undensified portions.

[0015] According to a further another example based on Example 8 (“Example 9”), the method further includes: shaping the expanded polyethylene substrate into a tubular member.

[0016] According to a further another example based on Example 9 (“Example 10”), selectively densifying a portion of the expanded polyethylene substrate includes: applying heat to an outer surface of the expanded polyethylene substrate.

[0017] According to a further another example based on Example 9 (“Example 11”), the method further includes: placing the tubular member on a mandrel.

[0018] According to a further another example based on Example 11 (“Example 12”), selectively densifying a portion of the expanded polyethylene substrate includes: applying heat to an inner surface of the expanded polyethylene substrate.

[0019] According to a further example of Example 12 (“Example 13”), selectively densifying a portion of the expanded polyethylene substrate includes: selectively heating some portions of the mandrel.

[0020] According to a further example of Example 8 (“Example 14”), selectively densifying a portion of the expanded polyethylene substrate includes: applying ultrasonic energy to the outer surface of the expanded polyethylene substrate.

[0021] According to a further example of Example 8 (“Example 15”), selectively densifying a portion of the expanded polyethylene substrate includes: applying ultrasonic energy to the inner surface of the expanded polyethylene substrate.

[0022] According to an example (“Example 16”), a method of forming an article includes: optionally providing an expanded polyethylene substrate having a first density, compressing the expanded polyethylene substrate in a longitudinal and / or lateral direction such that the expanded polyethylene substrate is in a longitudinally and / or laterally compressed state, the expanded polyethylene substrate having a first density, selectively densifying a portion of the expanded polyethylene substrate while in the longitudinally and / or laterally compressed state to form a densified portion of the expanded polyethylene substrate, wherein the densified portion has a second density greater than the first density, and releasing the expanded polyethylene substrate from the longitudinally and / or laterally compressed state.

[0023] According to a further example of Example 16 (“Example 17”), the method further includes: shaping the expanded polyethylene substrate into a tubular member.

[0024] According to a further example of Example 17 (“Example 18”), selectively densifying a portion of the expanded polyethylene substrate includes: applying heat to the outer surface of the expanded polyethylene substrate.

[0025] According to a further example of Example 17 (“Example 19”), the method further includes: placing the tubular member on a mandrel.

[0026] According to a further example of Example 19 (“Example 20”), selectively densifying a portion of the expanded polyethylene substrate includes: applying heat to the inner surface of the expanded polyethylene substrate.

[0027] According to a further example of Example 20 (“Example 21”), selectively densifying a portion of the expanded polyethylene substrate includes: selectively heating some portions of the mandrel.

[0028] Another example further to Example 16 (“Example 22”), selectively densifying a portion of the expanded polyethylene substrate includes: contacting a portion of the expanded polyethylene substrate with a component at about 110 degrees Celsius to about 180 degrees Celsius.

[0029] Another example further to Example 16 (“Example 23”), selectively densifying a portion of the expanded polyethylene substrate includes: applying ultrasonic energy to the outer surface of the expanded polyethylene substrate.

[0030] Another example further to Example 16 (“Example 24”), selectively densifying a portion of the expanded polyethylene substrate includes: applying ultrasonic energy to the inner surface of the expanded polyethylene substrate.

[0031] The above examples are limited to this and should not be construed as limiting or otherwise narrowing the scope of any inventive concept provided by the present disclosure in other ways. Although multiple examples are disclosed, other embodiments will be apparent to those skilled in the art from the following detailed description that shows and describes exemplary examples. Therefore, the drawings and the detailed description are considered to be illustrative rather than restrictive in nature. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are used to further understand the present disclosure, which are incorporated into this specification and form a part of this specification. The drawings illustrate embodiments of the present disclosure and, together with the specification, are used to explain the principles of the present disclosure.

[0033] Figure 1 is an imprinted article of expanded polyethylene according to some embodiments;

[0034] Figure 2 is an imprinted article of expanded polyethylene showing an inner surface and an outer surface according to some embodiments;

[0035] Figure 3 is an imprinted article of expanded polyethylene shown in a bent configuration according to some embodiments;

[0036] Figure 4 is a method of manufacturing an imprinted article of expanded polyethylene according to some embodiments;

[0037] Figure 5 is according to some embodiments, by Figure 4 the method in manufactures an imprinted article of expanded polyethylene;

[0038] Figure 6 is a method of manufacturing an imprinted article of expanded polyethylene having a reserve length according to some embodiments; and

[0039] Figure 7 is according to some embodiments, byFigure 6 An expanded polyethylene imprinted article manufactured by the method in Detailed implementation manners

[0040] Definitions and Terms

[0041] The present disclosure is not intended to be construed in a limiting manner. For example, the terms used in this application should be construed broadly in the context of the meanings given to such terms in the art.

[0042] For imprecise terms, the terms "about" and "approximately" are used interchangeably and are intended to mean that a measured value includes the measured value and also includes any measured value reasonably close to the measured value. As understood and readily determined by one of ordinary skill in the relevant art, a measured value reasonably close to the measured value deviates from the measured value by a relatively small amount. Such deviation may be attributable to measurement error, differences in calibration of measurement and / or manufacturing equipment, human error in reading and / or setting measurements, fine-tuning to optimize performance and / or structural parameters in consideration of measurement differences associated with other components, specific implementation scenarios, imprecise adjustment and / or operation of objects by humans or machines, etc. If it is determined that a person of ordinary skill in the relevant art cannot readily determine the value of such a reasonably small difference, the terms "about" and "approximately" may be understood to mean plus or minus 10% of the stated value.

[0043] As used herein, the term "laminate" refers to a multi-layer film-like material, composite material, or other material, such as but not limited to polymers, such as but not limited to elastomers, elastomeric or non-elastomeric materials, and combinations thereof.

[0044] As used herein, the term "film" generally refers to one or more of a membrane, a composite material, or a laminate.

[0045] As used herein, the term "polyethylene" (PE) includes all types of polyethylene, including but not limited to expanded polyethylene (ePE).

[0046] As used herein, the term "selective densification" generally refers to densification at a predetermined location on a substrate and includes different degrees of densification, including partial densification (such that the substrate remains porous and open after densification), and complete densification (wherein the substrate has a closed microstructure). Selective densification may include but is not limited to: densifying through a certain thickness of the substrate or along a certain length of the substrate while adjacent regions remain undensified.

[0047] Description of Each Embodiment

[0048] Those skilled in the art will understand that various aspects of the present disclosure can be implemented by any number of methods and devices configured to perform the required functions. It should also be noted that the accompanying drawings referred to herein are not necessarily drawn to scale and may be enlarged to illustrate various aspects of the present disclosure. In this regard, the drawings should not be considered limiting.

[0049] Figure 1 The devices shown in are provided as examples of various features of the device. Although combinations of these illustrated features are clearly within the scope of the invention, this example and its description do not mean that the inventive concept provided herein is limited to one or more of those features from fewer features, additional features, or alternative features to Figure 1 those shown in.

[0050] Various forms of expanded polyethylene can be implemented in articles and methods, including but not limited to films, membranes, tapes, tubes, and the like. It is further understood that the expanded polyethylene can be provided with various properties, including: different thicknesses, fibril and node structures, porosity, density, and the like. Therefore, the embodiments discussed herein are not limited to specific initial conditions or forms, but are understood to broadly encompass any expanded polyethylene starting material suitable for the method.

[0051] Referring to Figure 1 , article 10 is shown. Article 10 includes an expanded polyethylene substrate 12 having a first region 14 and a second region 16. The first region 14 has a first density, while the second region 16 has a second density. The second density of the second region 16 is greater than the first density of the first region 14. In addition, the second region 16 is embossed. Article 10 can be provided in any configuration, including but not limited to those shown in the figures. Article 10 can be provided in various three-dimensional forms; for example, a tubular member or tubular form as Figure 1 shown in. Article 10 can also be formed into a two-dimensional form, such as a sheet. The sheet formed from article 10 can be provided in various configurations, such as a circular form, a rectangular form, or any other geometric form. It should be understood that any two-dimensional form can be operated to provide a three-dimensional form. For example, article 10 can be formed by: providing a sheet that is connected to itself (e.g., adhered, bonded, fused, etc.), thereby forming, for example, a tubular member. Providing article 10 in various forms can endow article 10 with specific properties unique to each form of article 10 or constant regardless of the form of article 10.

[0052] In one embodiment, such as Figure 1In the illustrated embodiment, the article 10 is formed as a tubular member 100. The tubular member 100 includes first and second regions 14, 16 that are operable to impart enhanced durability (including abrasion tolerance) when subjected to repeated bending actions, including in embodiments where comfort and durability are important factors. Additionally, the tubular member 100 exhibits torsional tolerance, bend radius, comfort, and a reserve length. Although these features are discussed specifically with respect to the tubular member 100, it is understood that the article 10 provided in other forms may include these and similar features.

[0053] With further reference Figure 1 , the tubular member 100 is provided with first and second regions 14, 16, where the second region 16 is a ring 102 that is a densified region positioned (e.g., extending) around the perimeter of the tubular member 100. The tubular member 100 may include a plurality of rings 102 that are densified regions of the tubular member 100, where each ring 102 is spaced apart from an adjacent ring 102 along the longitudinal length of the tubular member 100. Other geometries of circumferential out-of-round densified regions are also contemplated. For example, the densified region may be formed as a helical pattern along the longitudinal length of the tubular member. The longitudinal length may be along the longitudinal axis of the tubular member 110. Providing the ring 102 of the densified region provides radial support to the tubular member 100 to resist radial forces and collapse from external forces (such as mechanical contact, pressure gradients, etc.) or internal forces (such as pressure gradients). The ring 102 may be provided on the tubular member 100 such that the outer surface 104 is recessed while the inner surface 106 is constant (e.g., smooth), such as as Figure 2 shown in. Having a smooth inner surface 106 provides an internal lumen 108 (seen in Figure 2 ) through which fluid can pass without disrupting fluid dynamics. Having an outer surface 104 with a recess may allow the tubular member 100 to be more strongly anchored within a patient's lumen. It is understood that the recess of the ring 102 may alternatively be positioned such that the recess is formed in the inner surface 106 such that the outer surface 104 is smooth. In another alternative embodiment, the recess formed by the ring 102 may be on the inner and outer surfaces 104, 106 (e.g., alternating, zoned, etc.).

[0054] The article 10 may be provided in a variety of structures. In some embodiments, the article 10 includes a plurality of polymer layers. For example, the article 10 may be formed as a laminate of expanded polyethylene layers. The layers may be joined together via adhesives, bonding processes, or mechanical processes. In some embodiments, the article 10 is formed as a specific structure, such as the tubular member 100 described above. The article 10 may be substantially free of adhesives. In these embodiments, the structure may be formed by: bonding a portion of the article 10 to another portion of the article 10, or the article 10 may be provided in the shape of the structure (e.g., extrusion, etc.).

[0055] Reference Figure 3 shows an embodiment of the tubular member 100. The tubular member 100 includes a plurality of rings 102 (e.g., the second region 16 has been imprinted to form a densified portion of the article 10). The tubular member 100 is shown in a bent configuration 160, wherein the tubular member 100 is resistant to torsion. The rings 102 provided in the tubular member 100 help enable the tubular member 100 to withstand a short bend radius without twisting, which allows the internal cavity 108 to remain open and helps fluid flow through the internal cavity 108 without blocking or disrupting the hydrodynamics. Because the tubular member 100 does not twist, the tubular member 100 is more durable, as twisting typically defines a weak spot over time on an implantable device. This is especially true when the implantable device is positioned within an active cavity of a patient that undergoes changes in shape, orientation, position, etc.

[0056] Reference Figure 4 , according to some embodiments, a method 400 of forming an expanded polyethylene article is provided. The manufacturing method may include the following method steps: providing an expanded polyethylene substrate 410, selectively densifying a portion 420 of the expanded polyethylene substrate, and optionally, shaping the expanded polyethylene substrate into an expanded polyethylene article 430.

[0057] Further reference Figure 4 , in providing the expanded polyethylene substrate 410, the polyethylene substrate has a first density. The expanded polyethylene substrate may include, but is not limited to: film, membrane, laminate, etc. Providing the expanded polyethylene substrate 410 may further include: positioning the expanded polyethylene substrate on a surface (e.g., Figure 5 the surface 202). The surface may include a mandrel.

[0058] Figure 4 Further, in selectively densifying a portion 420 of the expanded polyethylene substrate, a densified portion of the expanded polyethylene substrate is formed (e.g., Figure 1The second region 16 of the middle tubular member 100. 1). Selective densification refers to densifying a part 420 of the expanded polyethylene substrate such that the density of this part in the expanded polyethylene substrate increases 420. In some embodiments, selective densification includes: increasing the density while maintaining voids 420 in the selectively densified part of the expanded polyethylene substrate (e.g., not fully densified so that an open microstructure is retained). In some embodiments, selective densification includes: increasing the density without retaining pores (e.g., fully densifying so that there is no open microstructure). The part 420 of the expanded polyethylene substrate that is not selectively densified is a porous part that defines the undensified part. Selective densification can be achieved through the thickness of the expanded polyethylene substrate 420 or along the length of the expanded polyethylene substrate 420. The densified part of the expanded polyethylene substrate 420 may not be densified throughout the thickness of the expanded polyethylene substrate 420, such that at least some pores are retained in the thickness of the expanded polyethylene substrate 420. In some embodiments, the undensified part of the expanded polyethylene substrate 420 can be selectively masked such that the undensified part remains undensified and porous. The densified part of the expanded polyethylene substrate has a second density, and the second density can be greater than the first density. The densified part of the expanded polyethylene substrate can be disposed adjacent to the part of the expanded polyethylene substrate having the first density. Selective densification of a part 420 of the expanded polyethylene substrate can be achieved by imprinting. Selective densification of a part 420 of the expanded polyethylene substrate can further include: applying heat to the outer surface of the expanded polyethylene substrate (e.g., Figure 1 and 2 the outer surface 104 of the tubular member 100). Selective densification of a part 420 of the expanded polyethylene substrate can further include: applying heat to the inner surface of the expanded polyethylene substrate (e.g., Figure 2 the inner surface 106 of the tubular member 100). Applying heat to the expanded polyethylene substrate can further include: placing the expanded polyethylene substrate on a mandrel and selectively heating some parts of the mandrel (e.g., Figure 5 the surface 202).

[0059] Further referring to Figure 4 , method 400 can optionally further include: shaping the expanded polyethylene substrate into an expanded polyethylene article 430. The expanded polyethylene article can include a tubular member. Shaping the expanded polyethylene into the tubular member can further include: placing the tubular member on a mandrel. In some embodiments, the expanded polyethylene article can be shaped by: bonding a part of the article to another part of the article, or the article can be provided in the shape of the structure (e.g., extrusion, etc.).

[0060] Figure 5 shows an embossed article 220 of expanded polyethylene produced by the method in Figure 4 . Figure 5 Including: providing an expanded polyethylene substrate 200 (such as a film, film-like material, laminate, etc.). The expanded polyethylene substrate 200 can be a tubular member (such as Figure 1 the tubular member 100). The expanded polyethylene substrate 200 can have an outer surface 206 and an inner surface 208 (such as a lumen). The expanded polyethylene substrate 200 can be positioned on a surface 202 (such as a mandrel) for further processing of the expanded polyethylene substrate 200. When positioned on the surface 202, the expanded polyethylene substrate 200 has a first density. The first density can be substantially uniform throughout the expanded polyethylene substrate 200, or a portion of the expanded polyethylene substrate 200 can have a uniform first density. Once the expanded polyethylene substrate 200 is provided and positioned together with the surface 202, the expanded polyethylene substrate 200 can be selectively densified. The selective densification can include embossing. The embossing can occur via an external device (not shown; such as a soldering iron, heating pestle, ultrasonic bonding, etc.), or the embossing can occur via the surface 202 (such as heating the mandrel, etc.). Embossing via an external device can selectively densify the outer surface 206 and / or the inner surface 208. Embossing via the surface 202 can selectively densify the inner surface 208.

[0061] In some embodiments, the embossing or selective densification of the polyethylene substrate 200 can be achieved via ultrasonic energy. The ultrasonic energy can be applied to the outer surface 206 and / or the inner surface 208 of the polyethylene substrate 200 (such as using a mandrel). A rotary ultrasonic bonding unit including an angular anvil assembly can be used to apply the ultrasonic energy. The anvil can include a pattern (such as a circumferential ring) that can be embossed onto the polyethylene substrate 200. Using ultrasonic energy can allow the polyethylene substrate 200 to have a more discrete density and porosity difference between the embossed portion and the unembossed portion of the polyethylene substrate 200. This may be because the unembossed portion is less affected by the ultrasonic energy compared to applying heat. This can allow the unembossed portion to better retain its density and porosity.

[0062] As the expanded polyethylene substrate 200 is embossed, the embossed portion is densified to have a second density greater than the first density. The embossing can be completed in multiple steps such that the expanded polyethylene substrate 200 has both an embossed portion 210 and an unembossed portion 212. The embossing can be completed along the entire expanded polyethylene substrate 200 to produce the embossed article 220. It should also be understood that due to the embossing of the expanded polyethylene substrate 200, the embossed configuration (such as a pattern) can cause the expanded polyethylene substrate 200 to shorten. For example, Figure 4Shown is an expanded polyethylene substrate 200, provided as an expanded polyethylene 230 tubular member, embossed on an outer surface 206 to include a circumferential ring 204. When the circumferential ring 204 is embossed into the outer surface 206 of the expanded polyethylene 230 tubular member, the longitudinal length of the expanded polyethylene tubular member is shortened. The longitudinal length may be defined along a longitudinal axis L of the expanded polyethylene tubular member. The expanded polyethylene substrate 200 is provided with a first longitudinal length L1. When an embossed portion 210 is formed on a portion of the expanded polyethylene substrate 200, the expanded polyethylene substrate 200 has an intermediate longitudinal length LI. The intermediate longitudinal length LI is shorter than the first longitudinal length L1. When the embossed portion 210 is formed to the extent of the entire expanded polyethylene substrate 200 to produce an embossed tubular article 220, the embossed tubular article 220 has a second longitudinal length L2. The second length L2 is shorter than the intermediate length LI. In some embodiments, the change in length between the first longitudinal length L1 and the second longitudinal length L2 is small.

[0063] It should also be understood that the densification or embossing process may or may not densify the expanded polyethylene substrate 200 throughout the thickness of the embossed portion 210 of the expanded polyethylene substrate 200. For example, the expanded polyethylene substrate 200 may be densified only in a portion of the thickness of the expanded polyethylene substrate 200 such that there is a portion of the thickness that is not embossed (e.g., an inner surface 208 of the expanded polyethylene 230 tubular member). This unembossed portion of the thickness may substantially retain the first density (e.g., on the inner surface 208). Thus, in the case where the densified portion is located on the outer surface 206, when observing a cross-section of the expanded polyethylene substrate 200, at the embossed portion 210, there is a continuous density range in the entire thickness of the expanded polyethylene substrate 200 at the embossed portion 210. Thus, the inner surface 208 may substantially retain its porosity and hydrodynamic and / or hemodynamic properties by substantially retaining the first density.

[0064] The embossing or selective densification of the expanded polyethylene substrate 200 can be achieved by heating the expanded polyethylene substrate 200 using a tool at about the melting temperature of the expanded polyethylene substrate 200 or at a temperature of about 110°C to about 180°C. For example, the expanded polyethylene substrate 200 can be selectively heated to temperatures of about 110°C to about 120°C, about 120°C to about 130°C, about 130°C to about 140°C, about 140°C to about 150°C, about 150°C to about 160°C, about 160°C to about 170°C, and about 170°C to about 180°C.

[0065] Reference Figure 6, according to some embodiments, a method 600 of forming an expanded polyethylene article is provided. The manufacturing method may include method steps comprising: providing an expanded polyethylene substrate 610, compressing the expanded polyethylene substrate into a compressed state 620, selectively densifying a portion of the expanded polyethylene substrate 630, releasing the expanded polyethylene substrate from the compressed state 640, and optionally shaping the expanded polyethylene substrate into an expanded polyethylene article 650.

[0066] Further reference Figure 6 , in providing the expanded polyethylene substrate 610, the expanded polyethylene substrate has a first density. The expanded polyethylene substrate may include, but is not limited to: film, membrane, laminate, etc. The expanded polyethylene substrate may include a tubular member (e.g. Figure 7 the expanded polyethylene tubular member 300). Providing the expanded polyethylene substrate 610 may further include: placing the expanded polyethylene substrate on a surface. The surface may include a mandrel (e.g. Figure 7 the mandrel 302).

[0067] Further reference Figure 6 , compressing the expanded polyethylene substrate into a compressed state 620 may be performed in the longitudinal direction and / or the lateral direction such that the expanded polyethylene substrate is in a longitudinally and / or laterally compressed state.

[0068] Further reference Figure 6 , selectively densifying a portion of the expanded polyethylene substrate 630 may be accomplished while the expanded polyethylene substrate is in a longitudinally and / or laterally compressed state, thereby forming a densified portion of the expanded polyethylene substrate (e.g. Figure 7 the densified portion 306). The densified portion has a second density, and the second density may be greater than the first density. The densified portion of the expanded polyethylene substrate may be adjacent to an undensified portion of the expanded polyethylene substrate having the first density (e.g. Figure 7 the undensified portion 308). Selectively densifying a portion of the expanded polyethylene substrate 630 may be achieved by embossing. Selectively densifying a portion of the expanded polyethylene substrate 630 may further include: applying heat to an outer surface of the expanded polyethylene substrate (e.g. Figure 7 the outer surface 312). Selectively densifying a portion of the expanded polyethylene substrate 630 may further include: applying heat to an inner surface of the expanded polyethylene substrate (e.g. Figure 7 the inner surface 314). Applying heat to the expanded polyethylene substrate 630 may further include: placing the expanded polyethylene substrate on a mandrel and selectively heating some portions of the mandrel.

[0069] Further referenceFigure 6 Releasing the expanded polyethylene substrate from the compressed state 640 includes: releasing the expanded polyethylene substrate from a longitudinally and / or laterally compressed state. Method 600 may additionally include: shaping the expanded polyethylene substrate into an expanded polyethylene article 650. The expanded polyethylene article may include a tubular member. Shaping the expanded polyethylene into the tubular member may further include: placing the tubular member on a mandrel.

[0070] Furthermore, Figure 7 is an expanded polyethylene embossed article 10 manufactured by the method in Figure 6 According to some embodiments. In some embodiments, an embossed article 320 may be provided with a stock length. This may be achieved via the method of manufacturing article 10. The method of manufacturing the article may be the same as Figure 6The methods shown are substantially similar. For example, the method includes: providing an expanded polyethylene substrate having a first density, such as a tubular member 300, which is placed on a surface 302 (such as a mandrel 302). The expanded polyethylene substrate is not limited to the tubular member 300 and may include, but is not limited to, a flat member, or other geometric shapes. The expanded polyethylene substrate may be provided with an original length X1. The tubular member 300 includes an outer surface 312 and an inner surface 314 (such as a lumen). Once the tubular member 300 is positioned, the tubular member 300 is compressed in a longitudinal direction or a lateral direction into a compressed state 304 (such as not compressed throughout the entire thickness of the tubular member 300). In this embodiment, the compressed state 304 is defined in the longitudinal direction, which is defined by the longitudinal axis L of the tubular member 300. The compressed state 304 may have a post-compression length XC, which is less than the original length X1. While the tubular member 300 remains in the compressed state 304 (such as, the tubular member 300 remains in the longitudinally compressed state 304), the tubular member 300 is selectively densified to form a densified portion 306. The densified portion 306 of the tubular member 300 may be adjacent to an undensified portion 308. The densified portion 306 of the tubular member 300 has a second density, which is greater than the first density of the tubular member 300 before densification. Selective densification may be accomplished via imprinting. Similar to the discussion above, the imprinting process may or may not densify the tubular member 300 throughout the entire thickness of the tubular member 300 at the densified portion 306. For example, the tubular member 300 may be densified only in a portion of the tubular 300 (such as the outer surface 312 of the tubular member 300), such that there is a portion of the thickness of the tubular member 300 that remains undensified (such as the inner surface 314 of the tubular member 300). The undensified portion of the tubular member thickness may substantially retain the first density (such as on the inner surface of the tubular member 300). Thus, in the case where the densified portion is located on the outer surface 312 of the tubular member 300, when observing a cross-section of the tubular member 300, at the densified portion 306, throughout the entire thickness of the tubular member 300, the density at the densified portion 306 is a continuous range of densities. Thus, the inner surface of the tubular member may substantially retain its porosity and hydrodynamic and / or hemodynamic properties. The tubular member 300 may be imprinted or densified into various patterns, including but not limited to a ring 310. This results in a densified tubular member 320.

[0071] After the tubular member 300 is selectively densified, the tubular member 300 is released from the compressed state 304, and during the densification process, the tubular member 300 remains in the compressed state. As Figure 7As seen, when the tubular member 300 is released from the compressed state 304, the densified tubular member 320 does not return to the original length X1 of the tubular member. In some embodiments, the shortened length (or width) X2 of the densified tubular member 320 may be the result of imprinting the tubular member 300 in the compressed state 304. Additionally, the shortened length (or width) X2 may be the result of an imprinting or densifying step. In any case, imprinting the tubular member 300 in the compressed state 304 contributes to the stored length within the expanded polyethylene substrate. By applying a force at either end of the densified tubular member 320, the densified tubular member 320 can expand, thereby releasing the stored length and creating an expanded densified tubular member 330. The expanded densified tubular member 330 has an expanded length (or width) X3. The expanded length (width) X3 may include the full stored length or a portion of the stored length. In embodiments where the entire stored length is included in the expanded length (or width) X3, the expanded length (or width) X3 may be substantially the same as the original length X1. In other embodiments, the expanded length (or width) X3 may be less than the original length X1.

[0072] In some embodiments, the expanded polyethylene substrate is not provided as the tubular member 300, but is formed into a tubular member. This may occur before or after the imprinting / densifying process described herein. For example, the expanded polyethylene substrate may be formed into a tubular member and then placed on a mandrel for densification, similar to the densification process shown in Figure 7 . Any suitable method (including extrusion, bonding, adhesion, joining, etc.) may be used to form the expanded polyethylene substrate into a tubular substrate. In other embodiments, a tubular member is formed after imprinting / densifying the expanded polyethylene substrate, for example, by bonding, adhering, or joining the ends of the imprinted expanded polyethylene substrate to each other.

[0073] In some embodiments, imprinting / densifying the expanded polyethylene substrate includes selectively applying heat to an outer surface of the expanded polyethylene substrate. In some embodiments, the densification can occur at a temperature above the melting temperature of the expanded polyethylene substrate. In other embodiments, if an adhesive is present, the densification can occur at the melting temperature of the adhesive. In some embodiments, the expanded polyethylene substrate is a tubular member 300. Heat can be applied via a heating element such as an iron, a heat press, a heated tool element, and the like. Heat is applied to the outer surface (e.g., outer surface 312 of tubular member 300) so as to maintain the structural features of the inner surface (e.g., inner surface of tubular member 300). By maintaining the inner surface of the expanded polyethylene substrate, properties and functions can be retained. For example, the outer surface can have a densified ring (e.g., ring 310) for structural support (e.g., formed by a densification process), while the inner surface fully retains its selected structural qualities for, e.g., hemodynamics, cell adhesion, texture, and the like. It should be understood that the reverse configuration can be implemented, where the inner surface can be modified by densification while the outer surface fully retains the structure or other qualities on which the expanded polyethylene substrate was selected. In other embodiments, both the inner and outer surfaces can be modified to contribute to specific features of the inner or outer surface, or to specific features of the imprinted article 320 defined by the expanded polyethylene substrate (e.g., further radial collapse tolerance, increased reserve length, enhanced bend radius, and the like). Heat can be applied to the expanded polyethylene substrate using a component at about the melting temperature of the expanded polyethylene substrate or at about 110°C to about 180°C. For example, the expanded polyethylene substrate can be selectively heated to a temperature of about 110°C to about 120°C, about 120°C to about 130°C, about 130°C to about 140°C, about 140°C to about 150°C, about 150°C to about 160°C, about 160°C to about 170°C, and about 170°C to about 180°C. In some embodiments where the expanded polyethylene substrate is formed into a tubular member 300 before imprinting / densifying, the tubular member is placed on a mandrel 302. When the tubular member is on the mandrel 302, the mandrel 302 can be selectively heated (e.g., in selected areas, including stripes, patterns, and the like). This aids in the imprinting / densifying of the inner surface of the tubular member 300.

[0074] Although various materials can be implemented in accordance with the present disclosure, in Figure 3 one embodiment shown, a multi-layer expanded polyethylene substrate having an open, ventilated structure without the use of an adhesive is provided. The multi-layer expanded polyethylene substrate is rolled into a tubular member (e.g., tubular member 100). Subsequently, the multi-layer expanded polyethylene substrate is selectively densified using local heating (e.g., via an iron) between about 110°C and about 180°C (e.g., at about 175°C). As Figure 3As shown, the selectively densified multi-layer expanded polyethylene substrate exhibits a high degree of curvature without twisting of the tubular member 100.

[0075] Reference Figure 5 , in a non-limiting embodiment, a 6-layer wound open, ventilated expanded polyethylene substrate (e.g., provided as expanded polyethylene substrate 200) can be provided. The multi-layer expanded polyethylene substrate is selectively heated so that some portions of the multi-layer expanded polyethylene substrate are densified into densified rings (e.g., circumferential ring 204). Using a soldering iron, the multi-layer expanded polyethylene substrate is selectively heated between about 110 °C and about 180 °C (e.g., at about 150 °C). Along the longitudinal length of the multi-layer expanded polyethylene substrate, the densified rings are spaced from each other by about 2 mm. Before heating, a multi-layer expanded polyethylene substrate having a length of about 9 cm (e.g., disposed on a mandrel, having a first length L1) can be provided, and when removed from the mandrel, it has a length of about 7 cm (e.g., a second length L2) because of the compression (i.e., densification) that occurs when the selectively heated densified rings are formed.

[0076] Reference Figure 7 , in a non-limiting embodiment, a 6-layer wound open, ventilated expanded polyethylene substrate (e.g., provided as tubular member 300) can be provided and placed on a mandrel (e.g., surface 302). The multi-layer expanded polyethylene substrate has a length of 9 cm (e.g., an original length X1). The multi-layer expanded polyethylene substrate is kneaded into a length of 5.5 cm. The multi-layer expanded polyethylene substrate is selectively heated so that some portions of the multi-layer expanded polyethylene substrate are densified into densified rings (e.g., a length XC after compression). Using a soldering iron, the multi-layer expanded polyethylene substrate is selectively heated between about 110 °C and about 180 °C. The multi-layer expanded polyethylene substrate is removed from the mandrel. When the multi-layer expanded polyethylene substrate is relaxed, the length of the multi-layer expanded polyethylene substrate is about 6 cm (e.g., a shortened length X2). The multi-layer expanded polyethylene substrate includes a reserve length that allows the multi-layer expanded polyethylene substrate to be stretched to a length greater than 6 cm (e.g., an expanded length X3). In some embodiments, before or after stretching, the expanded polyethylene substrate can return to a length greater than 6 cm.

[0077] Although specific embodiments are provided herein, it is understood that different settings and material properties can be selected and processed within the spirit of the present disclosure. Further, the specific embodiments provide temperatures, steps, and properties, and these temperatures, steps, and properties can be changed while still within the spirit of the present disclosure.

[0078] The invention of the present application has been generally described above and in connection with specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the invention. Accordingly, the embodiments are intended to cover such modifications and variations of the invention as fall within the scope of the appended claims and their equivalents.

Claims

1. An article, the article comprising: An expanded polyethylene substrate having a longitudinal length, a first zone, and a second zone, wherein the first zone has a first density and the second zone has a second density greater than the first density, and wherein the second zone is embossed.

2. The article according to claim 1, wherein the expanded polyethylene substrate is longitudinally and / or laterally compressed, defining a reserve length along at least a portion of the longitudinal length.

3. The article according to claim 1, wherein the expanded polyethylene substrate is a tubular member.

4. The article according to claim 3, wherein the second zone is a ring extending around the tubular member at a longitudinal position defined along the longitudinal length.

5. The article according to claim 4, wherein the second zone comprises: A plurality of rings extending around the tubular member at a plurality of longitudinal positions defined along the longitudinal length.

6. The article according to claim 1, wherein the expanded polyethylene substrate does not contain an adhesive.

7. The article according to claim 1, wherein the expanded polyethylene substrate comprises a plurality of expanded polyethylene layers joined together.

8. A method of forming an article, the method comprising: Selectively densifying a portion of an expanded polyethylene substrate to form one or more densified portions of the expanded polyethylene substrate, wherein the expanded polyethylene substrate has one or more undensified portions having a first density, and wherein the one or more densified portions have a second density greater than the first density, wherein the one or more densified portions are disposed adjacent to the one or more undensified portions.

9. The method according to claim 8, the method further comprising: shaping the expanded polyethylene substrate into a tubular member.

10. The method according to claim 9, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Applying heat to an outer surface of the expanded polyethylene substrate.

11. The method according to claim 9, the method further comprising: Placing the tubular member on a mandrel.

12. The method according to claim 11, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Applying heat to an inner surface of the expanded polyethylene substrate.

13. The method according to claim 12, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Selectively heating some portions of the mandrel.

14. The method according to claim 8, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Applying ultrasonic energy to an outer surface of the expanded polyethylene substrate.

15. The method according to claim 8, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Applying ultrasonic energy to an inner surface of the expanded polyethylene substrate.

16. A method of forming an article, the method comprising: Compressing an expanded polyethylene substrate in a longitudinal and / or lateral direction such that the expanded polyethylene substrate is in a longitudinally and / or laterally compressed state, the expanded polyethylene substrate having a first density; Selectively densifying a portion of the expanded polyethylene substrate in the longitudinally and / or laterally compressed state to form a densified portion of the expanded polyethylene substrate, wherein the densified portion comprises a second density greater than the first density; and Releasing the expanded polyethylene substrate from the longitudinally and / or laterally compressed state.

17. The method according to claim 16, the method further comprising: shaping the expanded polyethylene substrate into a tubular member.

18. The method according to claim 17, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Applying heat to an outer surface of the expanded polyethylene substrate.

19. The method according to claim 17, the method further comprising: Placing the tubular member on a mandrel.

20. The method according to claim 19, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Applying heat to an inner surface of the expanded polyethylene substrate.

21. The method according to claim 20, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Selectively heating some portions of the mandrel.

22. The method according to claim 16, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Contacting a portion of the expanded polyethylene substrate with a component at about 110 degrees Celsius to about 180 degrees Celsius.

23. The method according to claim 16, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Apply ultrasonic energy to the outer surface of the expanded polyethylene substrate.

24. The method according to claim 16, wherein selectively densifying a portion of the expanded polyethylene substrate comprises: Apply ultrasonic energy to the inner surface of the expanded polyethylene substrate.

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