Small diameter fiber braid with central core member
阅读说明：本技术 具有中心芯构件的小直径纤维编织物 (Small diameter fiber braid with central core member ) 是由 P.科菲 F.斯隆 于 2019-01-17 设计创作，主要内容包括：一种绳,包括：股线的编织护套,该护套具有外表面、内表面以及由该内表面限定并且具有体积的中空部分；和在管状编织护套的中空部分内的芯,使得当绳处于松弛状态时,管状编织护套具有圆筒形形状和中空部分的松弛体积,其中芯未填满管状编织护套的中空部分的松弛体积；当绳处于纵向拉伸状态时,管状编织护套在纵向拉伸下伸长,使得管状编织护套的中空部分的至少一部分的拉伸体积小于松弛体积；以及拉伸体积的管状编织护套的内表面接触并束紧芯的表面。(A rope, comprising: a braided sheath of strands, the sheath having an outer surface, an inner surface, and a hollow portion defined by the inner surface and having a volume; and a core within the hollow portion of the tubular braided sheath, such that when the cord is in a relaxed state, the tubular braided sheath has a cylindrical shape and a relaxed volume of the hollow portion, wherein the core does not fill the relaxed volume of the hollow portion of the tubular braided sheath; when the cord is in a longitudinally stretched state, the tubular braided sheath is elongated under longitudinal stretching such that a stretched volume of at least a portion of the hollow portion of the tubular braided sheath is less than a relaxed volume; and the inner surface of the tubular braided sheath of stretched volume contacts and constricts the surface of the core.)
1. A rope, comprising:
a tubular braided sheath of strands having an outer surface, an inner surface, and a hollow portion defined by the inner surface and having a volume; and
a core within the hollow portion of the tubular braided sheath;
the method is characterized in that:
the tubular braided sheath comprises strands each having a tensile strength of about 8 cN/dtex or greater;
when the cord is in a relaxed state, the tubular braided sheath has a substantially cylindrical shape with an outer diameter of about 20 μm to about 5mm and a relaxed volume of the hollow portion, wherein the core does not fill the relaxed volume of the hollow portion of the tubular braided sheath; and
when the cord is in a longitudinally stretched state, the tubular braided sheath is elongated under longitudinal stretching such that a stretched volume of at least a portion of the hollow portion of the tubular braided sheath is less than a relaxed volume; and
the inner surface of the stretched volume of the tubular braided sheath contacts and constricts the surface of the core such that slippage between the core and the tubular braided sheath is reduced.
2. The rope of claim 1 in which (i) the braid of the tubular braided jacket has a weave density of 30 to 3000 filament unit crossings per inch in the relaxed state; or (ii) the core is twisted with a twist level of greater than 0 up to 1600 turns per meter (tpm); or (iii) the core is a braided core; or (iv) the core occupies greater than about 95% of the volume of the hollow portion of the tubular braided sheath in the relaxed state; or (v) the number of strands (ends) of the tubular braided sheath is from 4 to 24; or (vi) the mass ratio of the mass of the tubular braided sheath per unit length of cord to the mass of the core is from about 95/5 to about 50/50; or (vii) the cord has a linear density of from about 30 to about 5000 denier; or (viii) the braid angle of the tubular braided sheath is about 5 ° to about 95 ° in a relaxed state, and the braid angle increases in a longitudinally stretched state; or (ix) any combination of (i) - (viii).
3. A cord as claimed in claim 1 or 2 wherein the relationship between the sheath and core member of the cord when in a relaxed state conforms to equation (I)
c/10≤p/t≤c/2 (I)
Where c is the number of braided carriers used for the sheath, p is the density of fabric per inch in the sheath, and t is the level of twisting of the filaments of the core in turns/meter.
4. The rope of any one of claims 1-3 in which the tubular braided jacket has a reduced fabric density in a longitudinally stretched state as compared to the fabric density in a relaxed state.
5. The rope of any one of claims 1-4 in which (x) each strand of the tubular braided jacket is independently a twisted or untwisted monofilament; or each strand of the tubular braided sheath is independently a multifilament yarn, either twisted or untwisted; or the tubular braided sheath is a combination of strands, wherein each strand is independently either twisted or untwisted monofilament or multifilament; and (xi) the core is a twisted or untwisted monofilament; or the core is a multifilament yarn, twisted or not; or the core is a combination of strands, wherein each strand is independently a twisted or untwisted monofilament or multifilament.
6. The rope of any one of claims 1-5, wherein:
(xii) The strands of the tubular braided sheath comprise filaments selected from: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (p-phenylene benzobisoxazole)Oxazole) filaments, ultra-high molecular weight polyethylene filaments, high modulus polyethylene filaments, polypropylene filaments, polyethylene terephthalate filaments, polyamide filaments, polyhydroquinone diimidazole pyridine filaments, high strength polyvinyl alcohol filaments, and combinations thereof;
(xiii) The core comprises one or more filaments selected from: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (phenylene benzobisoxazole)Oxazole) filaments, ultra high molecular weight polyethylene filaments, polypropylene filaments, high modulus polyethylene filaments, polyethylene terephthalate filaments, polyamide filaments, high strength polyvinyl alcohol filaments, and combinations thereof; or
(xiv) (xii) and (xiii).
7. Rope according to claim 6, characterized in that the strands of the tubular braided jacket comprise liquid crystal polyester filaments and the content of liquid crystal polyester filaments is at least 50 mass% with respect to the total mass of the tubular braided jacket.
8. The rope of any one of claims 1-7 in which the tubular braided jacket has an outer diameter of about 20 μm to about 5mm, or about 20 μm to about 3mm, or about 20 μm to about 1mm when the rope is in a relaxed state.
9. The rope of any one of claims 1-8 in which at least one of the core or the tubular braided jacket comprises filaments, fibers or strands having a coating of crosslinked silicone polymer or non-crosslinked silicone polymer or long chain fatty acids.
10. A rope according to any one of claims 1 to 9 in which the linear density of the jacket substantially matches the linear density of the core.
11. The rope of any one of claims 1-10 in which the tubular braided jacket comprises strands each having a tensile strength of 15 cN/dtex or greater, or 22 cN/dtex or greater.
12. Tensile member comprising a rope according to any one of claims 1-11, characterized in that the outer diameter of the tensile member is 0.04mm to 0.7mm, or to 0.6mm, or to 0.5 mm.
13. The tensile member of claim 14 wherein the tensile member is a medical wire or suture.
Technical Field
The present invention is directed to small diameter tensile load controlled (managed) braided ropes having increased overall strength and dimensional stability relative to conventional known ropes of the same diameter. The rope is suitable for applications requiring small diameters and high strength.
Background
Braided ropes having a central core structure are conventionally used in a variety of applications. Generally, in each of the known structures, a braided outer jacket is used to protect the inner core structure from, for example, abrasion and environmental stresses. The central core structure, whether a single component or a plurality of wires that may be intertwined, braided and/or further twisted (twisted), contributes to the strength and stiffness of the rope. Thus, conventionally, the strength of the cord can be increased by varying the size and configuration of the core. In applications such as large diameter ropes (rope), increasing the diameter of the core and thus the rope generally does not adversely affect the utility value. However, in applications where small diameter (less than 3mm) and high tenacity are required, increasing the strength by increasing the diameter of the cord is not a desirable approach.
Conventional ropes of double braided construction are known in which the cover and the central core are each designed to carry a significant portion of the tensile load respectively. These ropes, which can be used at diameters as small as about 0.25 inch (about 6mm), are typically made of lower modulus fibers such as nylon or polyester. Using such lower modulus materials, core-sheath structural ropes, in which the longitudinal stress load is shared proportionally (proportionally), can be constructed by appropriately adapting (adjusting) the twist, braiding pattern and lay angle of the core and sheath strands. However, when constructing ropes with high strength, the geometry of the high modulus material, such as high molecular weight polyethylene (HMPE) or Liquid Crystal Polymer (LCP), core and jacket cannot easily balance the longitudinal load, so in conventional high tenacity ropes the core is responsible for carrying substantially all longitudinal stresses.
The tensile load carried by conventional small diameter braided cords may be unevenly distributed between the braided jacket and the central core member. As a result, when these cords are stretched, the braided jacket and core respond differently to the application of the stretching force. The sheath will respond to the force independently of the central core member, causing the central wire to move longitudinally relative to the surrounding sheath. The core member, particularly if constructed from wire, may also flatten and redistribute itself within the sheath rather than maintaining a circular cross-sectional shape.
Thus, in many very thin strands of thin braid (less than about 3mm in diameter), the core member may generally be absent, primarily for simplicity of construction, and the thin strands may be configured as hollow braids. A significant disadvantage of this approach is that in order to progressively increase the load capacity of such small diameter ropes, a small amount of fiber may be added to each braided element. Adding to each element maintains the overall torque balance of the structure. Thus, in a 12-strand braided rope construction, each strand will increase in size to achieve an increase in rope strength. When handling very thin ropes (i.e. ropes with a diameter of less than 3mm) in this way, the rope manufacturer has to take into account the increased fibre denier available. For example, considering a 12-ply braided rope (where each ply is 100 denier LCP fibers), the next increment in available strength increase would be if each ply were composed of two 100 denier LCP fibers. However, this increase in total fiber count also results in an increase in total cord diameter of about 1.4 times the original diameter.
It would therefore be advantageous to have a structure for very thin and ultra-thin cords (outer diameter 1mm or less) designed for tensile load control such that all tensile stresses are borne proportionally by all the components of the cord, so that overall strength is increased with little or no corresponding increase in diameter, with the tensile forces being more evenly distributed between the core and sheath components, so that the entire structure of the cord will respond consistently (collectively) to the tensile forces, preferably without deformation of the normal shape of the cord. Furthermore, with such a structure of tensile load control, it should be possible to obtain ropes of a set diameter having increased stability and strength with respect to conventional ropes of the same diameter.
It is therefore an object of the present invention to design rope structures with an outer diameter of less than 6mm using high modulus fibers, wherein the design results in a tensile load controlled structure such that the tensile load is proportionally shared by all the components of the rope.
Disclosure of Invention
These and other objects are achieved by the present invention, a first embodiment of which provides a rope comprising:
a tubular braided sheath of strands having an outer surface, an inner surface, and a hollow portion defined by the inner surface and having a volume; and
a core within the hollow portion of the tubular braided sheath;
wherein:
the tubular braided sheath comprises strands each having a tensile strength of about 8 cN/dtex or greater;
when the cord is in a relaxed state, the tubular braided sheath has a substantially cylindrical shape with an outer diameter of about 20 μm to about 5mm and a relaxed volume of the hollow portion, wherein the core does not fill the relaxed volume of the hollow portion of the tubular braided sheath; and
when the cord is in a longitudinally stretched (tensioned) state, the tubular braided sheath is elongated under longitudinal stretching such that a stretched volume of at least a portion of the hollow portion of the tubular braided sheath is less than a relaxed volume; and
the inner surface of the stretched volume of the tubular braided sheath contacts and constricts (grips) the surface of the core such that slippage between the core and the tubular braided sheath is reduced.
In one aspect of the first embodiment, the braid of the tubular braided sheath in a relaxed state has a braid density of 30 to 3000 crossovers/inch (10 to 1200 filament unit crossovers/cm), and the braid density of the tubular braided sheath in a longitudinally stretched state is reduced as compared to the braid density in a relaxed state.
In another aspect of the first embodiment, the core component occupies greater than about 95% of the volume of the hollow portion of the tubular braided sheath in a relaxed state.
In further aspects of the first embodiment, each strand of the tubular braided sheath may be twisted (twisted) or untwisted monofilament, or twisted or untwisted multifilament, or the tubular braided sheath is a combination of strands, wherein each strand is independently either twisted or untwisted monofilament or multifilament.
In another aspect of the first embodiment, the strands of the tubular braided sheath may be filaments selected from the group consisting of: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (p-phenylene benzobisoxazole)Oxazole) filaments, ultra high molecular weight polyethylene filaments, high modulus polyethylene filaments, polypropylene filaments, polyethylene terephthalate filaments, polyamide filaments, polyhydroquinone diimidazole pyridine filaments, high strength polyvinyl alcohol filaments, and combinations thereof.
In a further aspect of the first embodiment, the number of strands (ends) of the tubular braided sheath may be 4 to 24.
In still other aspects, the core member may be a twisted or untwisted monofilament or multifilament structure; and/or one or more filaments may be selected from: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (p-phenylene benzobisoxazole)
In another aspect of the first embodiment, the tubular braided sheath of rope per unit length has a mass to mass of core ratio of about 95/5 to about 50/50.
In yet another aspect of the first embodiment, the tubular braided sheath has an outer diameter of about 20 μm to about 5mm when the cord is in a relaxed state.
In yet another aspect of the first embodiment, the cord has a linear density of from about 30 to about 5000 denier, or even from about 50 to about 5000 denier.
In another further aspect of the first embodiment, the braid angle of the tubular braided sheath is about 5 ° to about 95 ° in a relaxed state, and the braid angle increases in a longitudinally stretched state.
In a second embodiment, the present invention provides a rope according to the first embodiment and all of the above aspects, wherein at least one of the core and the tubular braided jacket comprises filaments, fibers or strands having a coating (cladding) of a cross-linked silicone polymer or a non-cross-linked silicone polymer or a long chain fatty acid.
In another embodiment, the invention relates to a medical wire or suture comprising a cord according to embodiments described herein having an outer diameter of about 0.04mm to about 0.7 mm.
In a particular aspect, (i) the braid of the tubular braided sheath in a relaxed state has a braid density of 30 to 3000 filament unit crossings per inch; or (ii) the core is twisted with a twist level of greater than 0 up to 1600 turns per meter (tpm); or (iii) the core is a braided core; or (iv) the core occupies greater than about 95% of the volume of the hollow portion of the tubular braided sheath in the relaxed state; or (v) the number of strands (ends) of the tubular braided sheath is from 4 to 24 ends (end); or (vi) the mass ratio of the mass of the tubular braided sheath per unit length of cord to the mass of the core is from about 95/5 to about 50/50; or (vii) the cord has a linear density of from about 30 to about 5000 denier; or (viii) the braid angle of the tubular braided sheath is about 5 ° to about 95 ° in a relaxed state, and the braid angle increases in a longitudinally stretched state; or (ix) any combination of (i) - (viii).
In another particular aspect, (x) each strand of the tubular braided sheath is independently a twisted or untwisted monofilament; or each strand of the tubular braided sheath is independently a multifilament yarn, either twisted or untwisted; or the tubular braided sheath is a combination of strands, wherein each strand is independently either twisted or untwisted monofilament or multifilament; and (xi) the core is a twisted or untwisted monofilament; or the core is a multifilament yarn, twisted or not; or the core is a combination of strands, wherein each strand is independently a twisted or untwisted monofilament or multifilament.
In another particular aspect, (xii) the strands of the tubular braided sheath comprise filaments selected from the group consisting of: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (p-phenylene benzobisoxazole)Oxazole) filaments, ultra-high molecular weight polyethylene filaments, high modulus polyethylene filaments, polypropylene filaments, polyethylene terephthalate filaments, polyamide filaments, polyhydroquinone diimidazole pyridine filaments, high strength polyvinyl alcohol filaments, and combinations thereof; (xiii) The core comprises one or more filaments selected from: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (phenylene benzobisoxazole)Oxazole) filaments, ultra high molecular weight polyethylene filaments, polypropylene filaments, high modulus polyethylene filaments, polyethylene terephthalate filaments, polyamide filaments, high strength polyvinyl alcohol filaments, and combinations thereof; or both (xiv) (xii) and (xiii).
The foregoing description is intended to provide a general description and overview of the invention, and is not intended to be limiting of the disclosure, unless explicitly stated otherwise. The presently preferred embodiments, together with further advantages, will be best understood by reference to the following detailed description when considered in connection with the accompanying drawings.
Drawings
A more complete appreciation of the present disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
figure 1 shows a schematic view of a woven structure.
Figure 2 shows a schematic view of a 1x1 weave pattern.
Figure 3 shows a schematic view of a 2x 1 weave pattern.
Detailed Description
In the context of this specification, all publications, patent applications, patents, and other references mentioned herein are expressly incorporated by reference in their entirety for all purposes as if fully set forth, if not otherwise indicated.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In case of conflict, the present specification, including definitions, will control.
Trademarks are shown in capital letters unless explicitly noted.
All percentages, parts, ratios, etc., are by weight unless otherwise indicated.
When an amount, concentration, or other value or parameter is given as either a range or a list of upper and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper and lower value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. The following is not intended: when defining a range, the scope of the present disclosure is limited to the specific values recited.
When the term "about" is used, it is intended to indicate that a particular effect or result can be achieved within a tolerance, and one skilled in the art would know how to achieve that tolerance. When the term "about" is used to describe a value or an endpoint of a range, the disclosure should be understood to include the specific value or endpoint referred to.
As used herein, the terms "comprises," "comprising," "includes," "including," "has," "with," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The transitional phrase "consisting of … …" excludes any elements, steps, or components not specified in the claims, closing the claims from including materials other than the recited materials except for impurities often associated therewith. When the phrase "consisting of … …" appears in a clause of the subject matter of the claims, rather than immediately after the preamble, it restricts only the elements listed in that clause; in general, other elements are not excluded from the claims.
The transitional phrase "consisting essentially of … …" limits the scope of the claims to the specified materials or steps and those that do not materially affect the basic and novel features of the claimed invention. Claims "consisting essentially of … … are in the middle zone between closed claims written in the format" consisting of … … "and fully open claims written in the format" comprising ". By the term "consisting essentially of … …," optional additives as defined herein (at appropriate levels for such additives) as well as minor impurities are not excluded from the composition.
Furthermore, unless expressly stated to the contrary, "or" and/or "mean inclusive and not exclusive. For example, condition a or B, or a and/or B, is satisfied by any one of the following: a is true (or present) and B is false (or not present), a is false (or not present) and B is true (or present), and both a and B are true (or present).
The use of "a (or" an) (indefinite article ") to describe various elements and components herein is made merely for convenience and to give a general sense of the disclosure. The description is to be understood as including one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
As used herein, the term "major portion" or "predominantly" means greater than 50% of the material referred to, unless otherwise defined herein. If not indicated, when referring to molecules (e.g., hydrogen and ethylene), the percentages are by mole, and the others are by mass or weight (e.g., for additive content).
Unless otherwise defined, the terms "majority" or "substantially (broadly, considerably)" as used herein refer to all, almost all, or most, as will be understood by those of ordinary skill in the art in the context of use. Some reasonable differences from 100% that often occur in the case of industrial or commercial scale are intended to be taken into account.
The terms "barren (lacking, consuming)" or "reduced (decreasing )" are synonymous with decreasing relative to original presence. For example, removing a substantial portion of one material from a stream will produce a material-lean stream that is substantially deficient in that material. Conversely, the terms "enriched" or "increase (enlargement, elevation)" are synonymous with greater than originally present.
As used herein, the term "copolymer" refers to a polymer that includes copolymerized units resulting from the copolymerization of two or more comonomers. In this regard, a copolymer may be described herein with respect to its constituent comonomers or the amounts of its constituent comonomers, such as "a copolymer comprising ethylene and 15 wt% comonomer" or the like. Such a description may be considered informal in that it does not refer to comonomers as copolymerized units; it excludes the conventional nomenclature of copolymers, such as the International Union of Pure and Applied Chemistry (IUPAC) nomenclature; it does not use the term that defines the product-by-process by the method; or for other reasons. However, as used herein, the description of a copolymer with respect to its constituent comonomers or the amounts of its constituent comonomers means that the copolymer comprises copolymerized units of the specified comonomers (in the specified amounts, when specified). It follows that unless expressly so stated in limited circumstances, a copolymer is not the product of a reaction mixture comprising a given comonomer in a given amount.
Throughout this specification, unless otherwise defined and described, the technical terms and Methods used to determine relevant measurements are as described in ASTM D885M-94, Standard Test Methods for TireCords, Tire Cord Fabrics, and Industrial fiber Yarns From Man-madeOrganic-base Fibers [ Metal ], published in February 1995.
For convenience, many elements of the invention will be discussed separately, a list of options may be provided, and values may be in the form of ranges; however, in the context of the present disclosure, this should not be seen as limiting as follows: the scope of the disclosure or any claim of the disclosure to any such individual component, item, or any combination of ranges. Unless otherwise indicated, each combination possible with the present disclosure is to be considered explicitly disclosed for all purposes.
Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described herein. Thus, the materials, methods, and examples herein are illustrative only and, unless specifically stated, are not intended to be limiting.
As described in the background discussion, cord structures having an outer sheath of braided strands and a core component within the sheath are conventionally known and applied to different uses spanning from ordinary cords to textile cords. However, for specialized applications requiring thin and ultra-fine cords, achieving a minimum diameter cord while providing a product of high strength and stability is an ongoing research topic. As previously mentioned, increasing the strength of the hollow braided structure results in a significant increase in diameter.
Typically, the sheath functions to provide protection to the core element while the core carries tensile loads and is responsible for providing strength to the cord.
However, in applications where high strength and stability in combination with a small outer diameter (less than e.g. 1mm) is required, the inventors have investigated designs which can provide tensile load control in which tensile stress is shared by all components of the rope, and have considered that having a jacket structure which contributes to and/or proportionally takes up the tensile stress applied to the rope will provide a rope in which the overall diameter contributes in all respects to strength and stability and thus a rope having greater strength and dimensional stability than conventional core jacket ropes in which the jacket is used primarily as a protective layer on the core member: .
The present inventors have realized that with a specific structural arrangement of the core jacket, a fine diameter rope comprising high modulus fibers can be obtained, wherein the tensile force is more evenly distributed between the core and jacket components, such that the entire structure of the rope will respond consistently (collectively) to the tensile force, preferably without deformation of the normal shape of the rope. With such a construction it should be possible to obtain a rope of such a set diameter, which has an improved stability and strength with respect to conventional ropes of the same diameter. Unlike hollow braided fine or ultra-fine cords, the present inventors have concluded that providing a core structure will allow for incremental increases in strength through increasing the number of fibers while having minimal effect on diameter compared to increasing the number of fibers in a jacket braid as previously described. The inventors have found that finer increments of strength increase can be achieved, for example using a 100 denier fibrous LCP if increments of 1x100d are added step by step to the core element rather than to the sheath braid. Accordingly, the core member and sheath braid angles with braid and/or twist can be matched to evenly distribute stress loads between the core and sheath. For applications requiring ropes having a diameter of 5mm or less with a combination of high tensile strength and low creep, a design in which the tensile load is controlled to be proportionally distributed to the core and sheath would be advantageous.
Accordingly, in a first embodiment, the present invention provides a rope comprising:
a tubular braided sheath of strands having an outer surface, an inner surface, and a hollow portion defined by the inner surface and having a volume; and
a core within the hollow portion of the tubular braided sheath;
wherein:
the tubular braided sheath comprises strands each having a tensile strength of about 8 cN/dtex or greater;
when the cord is in a relaxed state, the tubular braided sheath has a substantially cylindrical shape with an outer diameter of about 20 μm to about 5mm and a relaxed volume of the hollow portion, wherein the core does not fill the relaxed volume of the hollow portion of the tubular braided sheath; and
when the cord is in a longitudinally stretched state, the tubular braided sheath is elongated under longitudinal stretching such that a stretched volume of at least a portion of the hollow portion of the tubular braided sheath is less than a relaxed volume; and
the inner surface of the stretched volume of the tubular braided sheath contacts and constricts the surface of the core such that slippage between the core and the tubular braided sheath is reduced.
In one embodiment of the cord, the relationship between the sheath and the core element of the cord when in a relaxed state conforms to equation (I)
c/10≤p/t≤c/2 (I)
Where c is the number of braided carriers used for the sheath, p is the density of fabric per inch in the sheath, and t is the twist level (twist) of the filaments of the core in turns/meter.
Desirably, the linear density of the jacket substantially matches the linear density of the core.
Tubular braiding about the core element is conventionally known, and tubular braided units are commercially available. A simple tubular braided sheath may be formed over the core member by: the strands of material are mechanically crossed diagonally in such a way that the groups of strands alternately pass above and below the groups of strands laid in opposite directions. A general diagram of the braided structure is shown in fig. 1, where the longitudinal braiding axis extends parallel to the direction of the rope and the wires parallel to the direction of a given braided strand define the braiding angle of the braided structure.
In addition to the braid angle, the braid may be characterized by a fabric density, defined as the number of needles or S units encountered per unit length along the longitudinal braid axis. Further, in addition to the weave density with respect to the longitudinal direction of the braid, the braid may be characterized by a thread count defining the number of repeating units per unit dimension along a thread perpendicular to the braiding axis. The braid angle, the fabric density and the number of threads can be determined by observing the braid under a microscope.
The actual weave pattern may vary depending on the weave (cross-over pattern). Common patterns include plain, twill and panama patterns (panama weaves), and these are known to those skilled in the art. In addition, different braided structures can be classified by the number of strands in the same weave side by side. Common weave patterns may be exemplified by, but are not limited to, a 1x1 pattern (fig. 2) and a 2x 1 pattern (fig. 3).
In all embodiments of the invention, the twist, weave pattern and lay angle of the strands of the central core and tubular braided sheath are designed to balance the tensile load between the core and sheath.
The weaving equipment is commercially available and devices (units) of different capabilities are available. In the embodiments described herein, the braid may be manufactured on steager (STEEGER USA, Inman, south carolina USA) and/or HERZOG (HERZOG GmbH, Oldenburg, Germany) braiding equipment designed for finer denier braiding. However, the apparatus is not limited to these devices. It is essential to the sheath core design that the braiding apparatus be equipped with the ability to braid around the central core. Steager is well known to those skilled in the art as a machine with sheath core capability. According to embodiments herein, the minimum number of carriers used to make a braid is three (3). The upper limit of the carrier is not limited and may be determined according to weaving parameters and design.
In a highly specific aspect of the invention, the surface of the core member may be corona or plasma treated prior to application of the tubular braided sheath. Such treatment may create surface imperfections or modifications (alterations) that enhance the contact surface interaction between the core component and the inner surface of the tubular braided sheath when in a longitudinally stretched state, further enhancing the cinching effect and improving the balance of load sharing between the core component and the sheath.
The invention according to the present embodiments and aspects may be obtained by applying any known pattern and characteristics as long as the disclosed elements are present.
According to an embodiment of the invention, the tubular braided sheath may be formed around the core component such that a volume of a hollow portion of the tubular braided sheath is not fully occupied by the core component when the tubular braided sheath is not under longitudinal tension and in a relaxed state. In the relaxed state, the braid may be defined by at least an outer diameter, a braid angle, and a fabric density. According to a first embodiment, the outer diameter of the braid (and thus the cord) is from about 20 μm to about 5mm, or from about 20 μm to about 3mm, or from about 20 μm to about 1 mm.
The tubular braided jacket may be prepared in an even number of strands and the rope construction according to the invention may have 4 to 24, or 4 to 18, or 4 to 12 strands (ends) per inch.
The tensile strength of each strand may be at least about 8 cN/dtex, or at least about 15 cN/dtex, or at least about 22 cN/dtex, and typically to about 30 cN/dtex. Higher tensile strength strands may be used as long as the strands are flexible enough to be handled in a braiding apparatus. If the strand tensile strength is less than about 8 cN/dtex, the strand may not have sufficient strength to cinch to the core when subjected to a longitudinally stretched state as described in the following paragraphs.
As described above, when the cord is in a relaxed state, there is an open volume in the hollow portion of the tubular braided sheath not occupied by the core member. In the relaxed state, the braid angle of the tubular braided sheath may be about 5 ° to about 85 °, or about 5 ° to about 90 °, or even about 5 ° to about 95 °. However, when longitudinal tension is applied to the cords, the applied tension results in a longitudinally stretched state in which the braided structure elongates, such that the braid angle increases and the fabric density decreases. Also, as a result of this elongation, the diameter (outer and inner) of the tubular braided sheath contracts such that at least a portion of the inner surface of the tubular braided sheath contacts and constricts the core member.
The tensile load control causes the core component and the braided tubular sheath to act together to provide tensile strength to the cord due to the effect of the lacing structure achieved under longitudinal tension and load balancing achieved by appropriate core and sheath design.
As will be appreciated by those skilled in the art, the lacing effect and tensile strength achieved according to the first embodiment may be adapted by: the weave pattern, number of strands, strand configuration, strand twist, weave angle and fabric density of the braid in the relaxed state are selected along with the core configuration and twist. The effect of these variables and other variables familiar to the skilled artisan in weaving techniques can be determined by routine experimentation and/or structural analysis.
The strand components of the tubular braided jacket may have a twisted or untwisted monofilament structure, a twisted or untwisted multifilament structure, or a combination of twisted or untwisted monofilaments and twisted or untwisted multifilaments. The monofilaments may be twisted, and the multifilament structure may be braided and/or twisted. In some aspects in which a twisted structure is present, the twisted structure may include a twist count of up to 1600 tpm.
The individual filaments may vary in weight from about 0.2 or from about 0.4 or from about 0.6 to about 10 or to about 8.0 or to about 6.0 denier. One of ordinary skill in the relevant art recognizes that the selected filament denier will vary with the chemical composition of the filament and the intended end use of the cord.
In one aspect of these embodiments, the strands of the sheath braid may be identical in size, structure and composition, or the strands may differ in any or all of size, structure and composition. Thus, the jacket may be constructed of strands of different denier, weave or twist, such that a firm grip or cinching of the core may be obtained when the cord is in a longitudinally stretched state. Further, the braid may comprise strands of different chemical compositions. Such a structure may be designed to further increase the strength and torque properties of the rope by experimental design tools as understood by those skilled in the art.
The chemical composition of the strands (or filaments) of the tubular braided sheath may be any high performance polymer known to provide a combination of high tensile strength, high toughness, and low creep, and may be selected from, but is not limited to, filaments selected from the group consisting of: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (p-phenylene benzobisoxazole)
More particularly, the strand preferably comprises, for example, at least one fiber selected from the group consisting of: liquid crystal polyester fibers, aramid fibers, PBO fibers, ultra-high molecular weight polyethylene fibers, and high strength polyvinyl alcohol fibers, more preferably at least one fiber selected from the group consisting of: liquid crystal polyester fibers and aramid fibers, and particularly preferably liquid crystal polyester fibers.
In one embodiment of the present invention, the liquid crystal polyester fiber may be obtained by melt spinning of a liquid crystal polyester resin. The spun fibers may be further heat treated to enhance mechanical properties. The liquid crystalline polyesters are composed of repeating polymerized units derived, for example, from aromatic diols, aromatic dicarboxylic acids, or aromatic hydroxycarboxylic acids. The liquid crystalline polyester may optionally further comprise polymerized units derived from an aromatic diamine, an aromatic hydroxylamine, or an aromatic aminocarboxylic acid.
Exemplary polymerized units are shown in table 1.
TABLE 1
(wherein, X in the formula is selected from the following structures)
(wherein m is 0 to 2, and Y is a substituent selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, and an aralkyloxy group)
The number of Y substituents in these formula ranges is equal to the maximum number of substitutable positions in the ring structure, and each Y independently represents a hydrogen atom, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (e.g., an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, or a tert-butyl group), an alkoxy group (e.g., a methoxy group, an ethoxy group, an isopropoxy group, a n-butoxy group, etc.), an aryl group (e.g., a phenyl group, a naphthyl group, etc.), an aralkyl group [ benzyl (benzyl group), phenylethyl (phenylethyl group), etc. ], an aryloxy group (e.g., a.
More preferred polymerized units may be the structures shown in tables 2, 3 and 4.
TABLE 2
TABLE 3
TABLE 4
When the polymerization unit in the formula is a unit that can represent various structures, two or more units may be used in combination as the polymerization unit constituting the polymer.
In the polymerized units of tables 2, 3 and 4, n is an integer of 1 or 2, and the corresponding units n ═ 1, n ═ 2 can be present alone or in combination; and Y1And Y2Each independently may be a hydrogen atom, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (e.g., an alkyl group having 1 to 4 carbon atoms such as methyl, ethyl, isopropyl or tert-butyl), an alkoxy group (e.g., methoxy, ethoxy, isopropoxy, n-butoxy, etc.), an aryl group (e.g., phenyl, naphthyl, etc.), an aralkyl group [ benzyl (benzyl), phenylethyl (phenethyl), etc. ]]An aryloxy group (e.g., phenoxy group, etc.) or an aralkyloxy group (e.g., benzyloxy group, etc.). In these groups, Y is preferably a hydrogen atom, a chlorine atom, a bromine atom or a methyl group.
Further, Z in the (14) row of table 3 may include a divalent group represented by the following formula.
The liquid-crystalline polyester may preferably be a combination including a naphthalene skeleton as a polymerization unit. Particularly preferably, it comprises both polymerized units (a) derived from hydroxybenzoic acid and polymerized units (B) derived from hydroxynaphthoic acid. For example, the unit (a) may have formula (a), and the unit (B) may have formula (B). From the viewpoint of improving melt formability, the ratio of the unit (a) to the unit (B) may be in the range of 9/1 to 1/1, preferably 7/1 to 1/1, more preferably 5/1 to 1/1.
The sum of polymerized units (a) and polymerized units (B) can be, for example, about 65 mole% or more, or about 70 mole% or more, or about 80 mole% or more, based on the total polymerized units. Liquid crystalline polyesters containing from about 4 to about 45 mole% of polymerized units (B) in the polymer may be particularly preferred.
The melting point of the liquid crystalline polyester may range from about 250 ℃ or from about 260 ℃ to about 360 ℃ or to about 320 ℃. The melting point as used herein is a main absorption peak temperature measured and observed by a differential scanning calorimeter (DSC; TA3000 manufactured by METTLER Co., Ltd.) according to JIS K7121 test method. Specifically, 10 to 20mg of the sample was used in the above-mentioned DSC apparatus, and after the sample was enclosed in an aluminum pan, nitrogen gas was flowed at a flow rate of 100 cc/min as a carrier gas, and an endothermic peak at heating at a rate of 20 ℃/min was measured. When a well-defined peak did not appear in the first run of the DSC measurement depending on the type of polymer, the temperature was raised to a temperature 50 ℃ higher than the expected flow temperature at a ramp-up rate (or heating rate) of 50 ℃/min, then completely melted at the same temperature for 3 min, and further cooled to 50 ℃ at a ramp-down rate (or cooling rate) of-80 ℃/min. Thereafter, the endothermic peak can be measured at a temperature rise rate of 20 ℃/minute.
Commercially available LCPs include those manufactured by KURARAY co
The liquid crystalline polyesters may be used alone or in combination.
According to the present invention, "aramid fiber" means a polyamide fiber having high heat resistance and high strength including a molecular skeleton composed of aromatic (benzene) rings.
Aramid fibers can be classified into para-aramid fibers and meta-aramid fibers according to their chemical structures.
The "aramid fiber" preferably includes para-aramid fiber.
Examples of commercially available aramid fibers include para-aramid fibers such as those manufactured by e.i. du Pont de nemoursard CompanyFrom Kolon Industries Inc
These aramid fibers may be used alone or in combination.
Polyhydroquinone diimidazole pyridine (PIPD) silk fibers are based on polymers of the following repeating units:
this material is commonly referred to as M5 and is available from DuPont.
Poly-p-phenylene benzobisAzole (poly (p-phenylene-2, 6-benzobis)
The ultra-high molecular weight polyethylene fibers according to this embodiment may have an intrinsic viscosity (intrinsic viscosity) in the range of about 5.0, or about 7.0, or about 10 to about 30, or to about 28, or to about 24 dL/g. Fibers with good dimensional stability are obtained when the inherent viscosity of the "ultra high molecular weight polyethylene fibers" is in the range of about 5.0 to about 30 dL/g.
ASTM standards describing dilute solution viscosity procedures for specific polymers such as nylon, poly (vinyl chloride), polyethylene, and poly (ethylene terephthalate) can be used (e.g., test methods D789, D1243, D1601, and D4603, and perform D3591). Typically, the polymer is dissolved in a dilution solution and the time of descent through the capillary relative to the control sample is measured at a particular temperature.
The weight average molecular weight of the "ultra high molecular weight polyethylene fibers" may be about 700,000, or about 800,000, or about 900,000 to about 8,000,000, or to about 7,000,000, or to about 6,000,000. When the weight average molecular weight of the "ultra-high molecular weight polyethylene fiber" is in the range of about 700,000 to about 8,000,000, high tensile strength and elastic modulus can be obtained.
The weight average molecular weight of the "ultra-high molecular weight polyethylene fiber" cannot be easily determined by a general GPC method, and therefore, can be determined based on the above-mentioned value of intrinsic viscosity according to the following equation mentioned in "Polymer Handbook fourth edition, chapter 4 (published by John Wiley, 1999)".
Weight average molecular weight of 5.365 × 104× (inherent viscosity)1.37
The following are preferred: the repeating units of the "ultra high molecular weight polyethylene fibers" are essentially ethylene. However, in addition to homopolymers of ethylene, copolymers of ethylene with small amounts of other monomers such as alpha-olefins, acrylic acid and its derivatives, methacrylic acid and its derivatives, and vinyl silanes and their derivatives may also be used. The polyethylene fibers may have a partially crosslinked structure. The polyethylene fibers may also be a blend of high density polyethylene and ultra high molecular weight polyethylene, a blend of low density polyethylene and ultra high molecular weight polyethylene, or a blend of high density polyethylene, low density polyethylene and ultra high molecular weight polyethylene. The polyethylene fibers may be a combination of two or more ultra-high molecular weight polyethylenes having different weight average molecular weights, or a combination of two or more polyethylenes having different molecular weight distributions.
Commercially available "ultra high molecular weight polyethylene fibers" include those made by TOYOBO coSK60、
These "ultrahigh molecular weight polyethylene fibers" may be used alone or in combination.
The core member may be a twisted or untwisted monofilament or a twisted or untwisted multifilament or a combination of twisted or untwisted monofilament and twisted or untwisted multifilament. The core member may be a braided structure. The core composition may be any of the high performance polymer filaments previously described, and may be a filament selected from the group consisting of: liquid crystal polyester filament, aramid filament, copolymer aramid filament, polyether ether ketone filament, poly (p-phenylene benzobisoxazole)
The composition of the core member filaments may be selected and structured for specific properties related to the intended end use of the cord.
Those skilled in the art recognize that in addition to the polymer composition of the selected core member, the weave or weave and/or twist applied to the core member (whether monofilament or multifilament) may be adjusted to vary and equalize the load sharing contribution of the core and tubular braided jacket in combination with the adaptation of the tubular braided jacket described above. In this manner, the overall tensile strength and dimensional stability of the cord may be increased while maintaining or reducing the diameter of the cord.
In one particular embodiment of the invention, the cord may comprise an LCP core component and an LCP tubular braided sheath. The configuration of the core and tubular braided sheath may vary within the variables described above and according to other variables known to those skilled in the art.
In a particular embodiment, the cords described in the above embodiments may be used as tensile members, where the tensile members have an outer diameter of about 0.04mm to about 0.7 mm. In other embodiments, the tensile member may have an outer diameter of about 0.04mm to about 0.6mm, or about 0.04mm to 0.5 mm. Exemplary tensile members are medical wires or sutures.
In another embodiment, the properties and characteristics of the rope can be modified and controlled by applying a finish composition as is conventionally known to those skilled in the art. For example, at least one of the core and/or the tubular braided sheath comprises filaments, fibers or strands having a coating of a cross-linked silicone polymer, or a non-cross-linked silicone polymer or a long chain fatty acid. An exemplary long chain fatty acid is stearic acid. Cords applying crosslinked silicone polymers to high performance polyethylene are described in US8881496B 2.
Applying a cross-linked silicone polymer, in particular to filaments and/or multifilaments contained in a tubular braided sheath and/or strands of a core, may provide advantageous performance enhancements to the tensile strength controlled cord structure of the present invention.
Generally, there are three crosslinking reaction methods that can be used to prepare silicone resins: 1) peroxide curing, wherein thermal activation of polymerization occurs under the formation of peroxy radicals; 2) condensation under the influence of heat or moisture in the presence of a tin salt or titanium alkoxide catalyst; and 3) addition reaction chemistry catalyzed by platinum or rhodium complexes that can be temperature or photoinitiated.
Each of these systems is commercially available, for example, from Dow Corning and is known to those skilled in the art.
The cross-linked silicone coating may enhance the moisture resistance of the strand, and may also enhance the lubricity of the strand, such that the braid responds more effectively when the cord is under longitudinal stress than an uncoated device in which it may be necessary to overcome frictional interactions before a lacing effect is obtained.
The coating composition may be applied by surface application techniques known to those skilled in the art. These surface application techniques may include simply pumping a finish agent solution through a finish guide where the fibers come into contact with the finish agent and wick into the fiber bundle by capillary action. Alternatively, other techniques may include spray coating, roll coating, or immersion application techniques such as dip coating. Subsequent treatment of the fiber with the finish solution applied may include contact with one or more rollers in order to set the finish and/or affect the degree of crosslinking in the finish formulation. The rollers may or may not be heated. The coating composition may then be cured to cause crosslinking of the crosslinkable silicone polymer. When thermal curing is used, the temperature may be from about 20 ℃, or about 50 ℃, or about 120 ℃ to about 200 ℃, or to about 170 ℃, or to about 150 ℃. The curing temperature may be determined by the thermal stability properties of the filaments, fibers or strands and the actual crosslinking system employed.
The degree of crosslinking achieved can be controlled to provide varying degrees of flexibility or other surface characteristics to the filaments, fibers, or strands. The degree of crosslinking can be controlled by methods described by the supplier of the crosslinking system and known to the person skilled in the art.
The degree of crosslinking can be determined by the method described in US8881496B2, wherein the coating is extracted with a solvent that dissolves the monomers but not the crosslinked polymer. The degree of crosslinking can be determined by the difference in weight before and after extraction.
The degree of crosslinking can be at least about 20%, or at least about 30%, or at least about 50%, based on the total weight of the coating. The maximum degree of crosslinking may be about 100%.
The weight of the crosslinked coating can be from about 1 wt.% to about 20 wt.%, or to about 10 wt.%, or to about 5 wt.%, based on the total weight of the filaments, fibers, or strands.
The previous description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. In this regard, in a broad sense, certain embodiments within the invention may not exhibit all of the benefits of the invention.
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