The invention relates to gloves and glove systems, particularly surgical gloves and glove systems offering one or more of puncture resistance, a pathogen barrier, and/or suitable dexterity, tactility, and comfort for the wearer.
Surgical gloves are typically made from natural rubber latex or a synthetic elastomer such as polyisoprene. Gloves manufactured from these highly elastic, low modulus materials closely conform to the wearers hand and bend and stretch easily to allow free hand movement while providing the requisite barrier to penetration by blood and bodily fluids that is an integral function of a surgical glove. However, latex gloves offer a vanishingly small level of resistance to puncture by a hypodermic or suture needle. Bloodborne diseases, including HIV and hepatitis, may be transmitted from patient to the healthcare worker in the event of a needle stick injury. Due to the fatal and irreversible consequences of contracting HIV, there is a need for a glove that can protect surgeons and healthcare workers by resisting puncture by a medical needle. Thus, ideal surgical gloves or glove systems need to offer protection against mechanical aggressors, (e.g. needles, sharp bone fragments or other surgical instruments), while also providing the barrier to bloodborne pathogen hazards. Ideally, these gloves should provide this protection while still allowing the wearer to perform his or her job without undue hindrance.
The danger of disease transmission to healthcare workers through needle injury is well-known and there have been a number of protective materials proposed in prior art. While these existing materials have some resistance to puncture, the mechanical properties of these materials are such that they have a strong negative influence on dexterity and tactile sensitivity when incorporated into a surgical glove. Protective equipment often utilizes textiles made from high strength and/or hard fibers like steel, glass fibers, UHMWPE, Kevlar® or Vectran®. Existing puncture resistant materials are typically very stiff and may severely hinder the comfort and tactile sensitivity of the wearer. Solid puncture resistant materials, such as polyethylene or leather, do not have the tip-puncture problem associated with textiles, but may be unacceptably stiff and therefore lead to severe reductions in dexterity and tactile sensitivity.
Existing cut-resistant gloves also typically have an open knit construction that offers no resistance to penetration by blood or other liquids. As a result, the viral barrier properties must be achieved by wearing multiple gloves. In some cases, the required barrier properties are achieved by triple gloving: a latex glove is worn both on top of and below the cut-resistant glove. The thickness of prior art three glove systems may significantly reduce dexterity and tactile sensation and may also be inconvenient to don.
It is particularly difficult to design a textile to protect against medical needles. The small size and sharp cutting edge allows the needle to penetrate the fabric either by cutting the yarns or displacing the yarns enough to create a “window” in the fabric. In needle protective gloves, including those designed for law enforcement and corrections applications, the high-strength fibrous materials are often present in the form of a woven textile (See, e.g. U.S. Pat. No. 4,742,578 to Seid). These woven textiles are engineered to have high yarn counts with minimal space between yarns to prevent a needle from slipping between yarns without engaging the fabric. Dense woven materials can sometimes provide a degree of needle protection, but the high fiber modulus and yarn count means that the materials may be quite stiff compared to a latex surgical glove. Nonetheless, woven materials are often marketed as flexible puncture protection, since the stiffness is not so great as to completely prevent movement of the finger and hand joints.
Flexibility on the length scale of hand movement alone may not be sufficient to permit a surgeon to carry out the delicate manipulations required to perform successful surgery. The glove material ideally should also conform to fine details and textures and provide a high degree of tactile sensitivity. Such sensitivity is critical to allowing a surgeon to successfully palpate tissue and diagnose the patient. Dense, stiff or thick materials do not afford sufficient tactile sensation to allow unhindered performance of operations requiring tactile feedback. In a study comparing the ability of surgeons to work while wearing Kevlar® cut-resistant glove and Kevlar® liners with added puncture resistance from a hide material versus single and double latex gloves, researchers found that the Kevlar® gloves only led to small increases in the time to complete simple motor tests, such as manipulations with forceps (Phillips, Birch and Ribbans, Ann. R. Coll. Surg. Engl., Vol. 79, p. 124, 1997). In tests requiring tactile evaluation, however, such as comparing the textures of two objects, surgeons took up to twice as long to complete the task while wearing the puncture-resistant liners as compared to latex gloves. The use of liners also increased the frequency of errors to greater than 25%, as compared to less than 5% for latex gloves. While a protective glove may permit the surgeon to perform basic motor operations with an acceptable level of hindrance, such gloves may be detrimental to operations requiring fine tactile sensation.
Alternative surgical gloves designed to offer needle puncture protection acknowledge the inadequate flexibility and tactility afforded by the puncture resistant textiles and uses stiff protective material as reinforcement only in the regions that are most likely to be punctured. Surveys indicate that the index finger, middle finger, thumb and a portion of the palm between these digits are the areas that are most likely to be injured (Jagger et al., AORN Journal, Vol. 67, p. 979, 1998). Thus, there have been a number of protective gloves proposed in the art that locate pieces of stiff or thick puncture resistant materials on the most at-risk portions of the hand. Examples include U.S. Pat. No. 4,864,661; No. 5,259,069; No. 5,423,090; and No. 6,081,927 to Gimbel and U.S. Pat. No. 5,231,700 to Cutshall, and the FingGuard™ protective pad previously made by Allied Signal. Unfortunately, for many applications, the most at-risk digits may also be the digits most used in manipulation of instruments and palpation of tissue, and the stiff woven puncture pads may still interfere with operations.
Knit textiles are typically more flexible than wovens. Knit high-modulus fibers have therefore been considered for puncture protective materials, but these knits may still lack the close fit and high tactile sensitivity desirable for surgical use. U.S. Pat. No. 5,564,127 to Manne describes a surgical glove comprising a panel of knitted textile made from a high strength material, such as steel, affixed to one aspect of a barrier glove, but such a glove is believed to have less-than-ideal flexibility. Other references describe gloves that utilize hard, discontinuous plates distributed on or within a fabric or elastomer. Examples of materials or gloves comprising puncture resistant plates on a fabric or polymer backing are described in U.S. Pat. No. 5,601,895 to Cunningham, U.S. Pat. No. 6,962,739 and No. 7,018,692 to Kim et al. and U.S. Pat. No. 7,504,145 to Vance et al. Examples of plates or other hard elements distributed within the volume of an elastomer are described in U.S. Pat. No. 5,368,930 to Samples, U.S. Pat. No. 5,200,263 and No. 5,514,241 to Gould et al., U.S. Pat. No. 5,317,759 to Pierce, U.S. Pat. No. 5,817,433 and No. 6,020,057 to Darras, U.S. Pat. No. 6,021,524 to Wu et al., U.S. Pat. No. 6,272,687 to Cunningham and U.S. Pat. No. 7,043,770 to Cunningham. Hard materials used to provide puncture-resistant functionality are not likely able to closely conform to small objects, so gloves incorporating such materials suffer from poor tactile sensitivity in the areas adjacent such materials. Where multiple layers of plates are required to prevent the needle from piercing through interstitial spaces between plates, such embodiments are unlikely to offer the level of tactility and close fit desirable in a surgical glove.
Accordingly, there is still a need in the art for a glove or system of gloves that does not hinder user's dexterity, tactility, and comfort, but provide both puncture resistance and barrier protection. As no glove is 100% effective, it is also desirable to provide a visual indication to the wearer of such a glove or glove system when it has been breached.
One aspect of the invention comprises a glove or partial glove comprising a palmar portion configured to be worn adjacent the palmar aspect of the wearer's hand and a dorsal portion configured to be worn adjacent the dorsal aspect of the wearer's hand, each of the palmar portion and the dorsal portion comprising one or more finger/thumb extensions, the palmar portion and dorsal portion joined together at a sealed seam, the seam positioned such that when worn by the user, the seam on each of the finger/thumb extensions is positioned adjacent the dorsal aspect of the user's finger/thumb with the palmar aspect extending over the fingertip in a hood-like configuration. In one embodiment, the portion of the seam closest to the fingertip may be aligned with the middle of each fingernail.
In some embodiments, each of the palmar portion and the dorsal portion may comprise a shear-thickening-fluid-treated textile base. The palmar portion and the dorsal portion may each have a multi-ply construction, wherein each ply comprises a shear-thickening-fluid-treated textile base. Multi-ply embodiments may comprise at least two plies of calendered, knit textile intercalated with the shear-thickening fluid, with the plies oriented such that warp directions of the two plies are oriented at 90 degrees relative to one another. In some embodiments, the glove may have a plurality of panels intercalated with shear-thickening fluid, wherein the shear-thickening-fluid-intercalated panels cover one or more selected sections of the wearer's hand consisting of less than all of the wearer's hand. The textile base may comprise a knit fabric, such as a warp knit or an interlock knit, or may comprise a woven or non-woven textile. The textile base may be calendered. In some embodiments, the glove may comprise a pathogen barrier, such as a coating that is impervious to blood and bloodborne pathogens.
The back portion of the glove may have one or more features for facilitating donning, such as, for example a stretchable donning panel or a slit in the dorsal portion. The glove may have an adjustable fit, such as embodiments comprising a drawstring or an elastic band inserted within a casing at or near a lower opening edge of the glove.
A partial glove embodiment may comprise a calendered, knit textile intercalated with shear-thickening fluid configured to provide puncture protection to the thumb, index finger, middle finger, all or a portion of the palmar aspect of the hand, all or a portion of the dorsal aspect of the hand, or a combination thereof.
Another aspect of the invention is a glove system comprising a first glove or partial glove component having a sealed seam with the seam on each of the finger/thumb extensions positioned adjacent the dorsal aspect of the user's finger/thumb with the palmar aspect extending over the fingertip in a hood-like configuration, wherein the first glove or partial glove component comprises a textile base treated with a shear-thickening fluid. The glove system may further comprise a second latex or synthetic surgical glove component worn on top of the first glove component, and, optionally, a third latex or synthetic surgical glove worn underneath the first glove component. In embodiments with a second glove, the second glove is sized and materials of construction are selected to apply a compressive force over substantially all of the first glove or partial glove component when the second glove is donned over the first glove or partial glove component. In some embodiments, the first glove or partial glove component comprises a two-ply palmar portion, a two-ply dorsal portion, and a discrete outer layer configured to serve as a pathogen layer.
The various aspects of the invention comprise a glove, partial glove, or system of gloves having one or more innovative features as described in more detail herein, any one, some, or all of which may be present. Each of these features is described herein separately and in combination with one or more of the other features. While each of these features may be suitable for practice in connection with a glove component or glove system having only a single feature as described herein, it should be understood that a glove component or glove system having any one of these features may be combined with the features described in one or more of the other sections, even if not explicitly discussed herein. Ideally, it is desired to provide a surgical glove or glove system that: 1) is resistant to needle puncture, 2) affords the wearer a level of tactile sensitivity that is comparable to conventional latex gloves, and 3) provides a barrier to blood, bodily fluids and bloodborne pathogens.
Various embodiments of the present invention described herein are resistant to puncture by medical needles and have materials and construction geometry selected to provide a higher degree of tactile sensitivity than existing puncture resistant gloves. Some embodiments may be constructed from multiple panels of a textile knit from a low modulus, multi-filament yarn, such as polyester. The use of a knit textile construction and low modulus fiber for the yarns allows such a glove to conform to fine details or textures of objects and tissues undergoing manipulation, thereby affording the wearer excellent tactile sensitivity. The knit is designed to have a high density and minimal stretch. The knit textile may be further subjected to a calendering process, in which heat and pressure are applied to decrease space between yarns. Tests showed improved puncture resistance for STF-treated calendered fabrics as compared to the same STF-treated fabrics that had not been subjected to a calendering process.
In some preferred embodiments, the knit textile may be intercalated with a shear-thickening fluid to provide a means for a yarn to locally rigidize upon application of stress via contact with a needle tip. The knit construction and density are such that, when the yarn under stress rigidizes, it is unable to move out of the path of the needle to create a window for puncture. Additionally, the textile construction may be such that the local rigidization aids in the transfer of load from the yarn under primary stress to those fibers that are entangled with the primary yarn in the knit. The knit construction and calendering process described above ensure a needle must engage a yarn and cannot pass through inter-yarn spaces in the textile.
Some preferred embodiments further comprise a barrier to bloodborne pathogens created by wearing a sterile, elastic surgical glove on top of the knit, shear-thickening fluid intercalated glove. The elastic glove also applies a compressive force over substantially the entire area of the hand. The compression of the textile glove by the outer elastic glove reduces open areas in the knit, thus favorably impacting the puncture resistance and tactile sensitivity. In an alternative embodiment, the textile glove may be worn between two elastic gloves to provide additional barrier protection in the event of a breach in the outermost elastic glove.
In some embodiments, the barrier to bloodborne pathogens may be created by coating or laminating the textile with a film of a suitable material, such as silicone, polyurethane or natural or synthetic latex. The coating or laminate may be attached to the textile using a suitable process to minimize the amount by which the coating penetrates into the knit, thereby minimizing any increase in the stiffness of the entire structure.
Another feature of some preferred embodiments of the invention comprise assembly of a three-dimensional glove shape from multiple panels of flat fabric. The shapes of said panels are such that, for the portions enclosing the finger stalls, a single panel covers the volar aspect and a portion of the sides of each finger. Additionally, at the distal end of the finger stall, the panel covering the volar aspect of the finger curves up and around towards the dorsal aspect to permit a single panel to cover substantially all of the fingertip. Panels of this shape allow the seams to be located away from areas of the finger that are critical for tactile tasks like palpation. Alternative embodiments may have welded seams in the textile instead of sewed seams to further decrease seam bulk and improve sensitivity.
When combined, the above features create a glove or glove system embodiment in which the wearer has excellent tactile sensitivity and may detect when an imminent threat of needle injury exists. The shear-thickening fluid intercalated knit acts to resist initial penetration of the glove to enable the wearer to remove his hand and/or cease the application of force to the needle. It should be understood, however, that gloves or glove systems containing fewer than all, including embodiments with only one of the features described herein, may still be an advance over the prior art and may be advantageous in certain embodiments even without being combined with other features discussed herein.
Thus in general, one aspect of the invention comprises a glove or glove system, such as to be worn during surgery, that provides an improved level of protection against accidental puncture injury. In one embodiment, the glove is constructed from a low-modulus yarn with a textile construction sufficient to provide a very high degree of flexibility over short length scales to afford the wearer excellent tactile sensitivity. The term “low-modulus” is used herein to refer generally to yarns with a Young's Modulus in a range that includes materials such as polypropylene, polyester, and nylon, which have a very low modulus in a range of 1-3 GPa, as well as any material in the range of 1-30 GPa, which is well below the range of relatively high modulus materials such as, for example, Kevlar (˜70 GPa) and steel. In certain embodiments, the glove construction locates seams away from critical areas on the fingers. In fact, one aspect of the invention comprises a textile-based, close-fitting glove or glove-system designed and assembled with as few seams as possible, each seam strategically positioned so as not to hinder the user's dexterity, tactile sensitivity and comfort. In embodiments that incorporate both mechanical protection and a pathogen barrier in a single glove, the system can be thinner and lighter, thereby having a minimal impact on the dexterity and tactile sensitivity of the wearer. Single glove embodiments are more convenient to don and are advantageous in situations where gloves may need to be rapidly donned or changed (such as in emergency rooms or if a doctor is moving from one operating room to another). Multi-glove systems as described herein are designed to minimize the number of gloves in the system and maximize dexterity and tactile sensitivity.
Multi-ply gloves and glove systems as described herein avoid the pitfalls of single ply textile materials that may be more susceptible to penetration because the tip of the needle can slip in between fibers/yarns before the thicker portions of the needle are fully engaged by the protective textile. Such multi-ply systems overcome the lack of spatial homogeneity in some knit or woven textiles, which have a relatively greater chance of a sharp needle point finding a small void space in the knit/weave without engaging the fibers. Multi-ply constructions disclosed herein counteract the ability of a small needle tip to penetrate the textile with minimal force. Because the two-ply STF-textile composite is more flexible than traditional puncture-resistant materials, it does not interfere with tactile sensitivity.
Accordingly, one embodiment comprises a glove for wearing on a user's hand, the glove comprising a palmar portion and a back portion, each of the palmar portion and the back portion comprising a plurality of finger/thumb extensions, the palmar portion and back portion joined together at a sealed seam, the seam positioned such that when worn by the user, the seam on the finger/thumb extensions is positioned adjacent the back side of the user's fingers and the palmar portion extends over the fingertips in a hood-like configuration. The palmar portion may extend over the wearer's fingertips such that the seam closest to the fingertip is aligned with the middle of each nail. The back portion of a glove having any or all of the features described above may further comprise a stretchable donning panel, such a panel comprising an elastomeric film, or other features for improving donning. The glove, including the seams and the donning panel, where present, may comprise a barrier that is pathogen resistant.
An exemplary seam construction for the glove assembly is a heat- or radio frequency-sealed simple lap seam configuration, whereby the seam is made by overlapping the seam allowances of each ply, each ply extending in the opposite direction from each other. This configuration reduces the amount of bulk in the seam allowance against the skin, making it more comfortable to the wearer and maximizing the wearer's tactile sensitivity. Another seam construction takes the traditional “needle-and-thread” assembly approach, utilizing a super-imposed plain seam that is sealed with seam tape or sewn with a low-temperature melting thread. A super-imposed plain seam may be assembled whereby the two or more plies are stacked one on top of the other with the edges even and sewing them together near the edge. Meltable thread, when heated, melts to permit the flowing polymer of the melted thread to fill the holes created by a sewing needle and the seam allowance spaces between the holes. Seam tape may be of any seam sealing formulation designed to make a seam impermeable.
While the above design may be useful for any type of multi-component glove having seams, in certain embodiments, the palmar portion and the back portion each may comprise a shear-thickening-fluid-treated (STF-treated) textile base. In one embodiment, the palmar portion and the back portion each may have a multi-ply construction, such as a two-ply construction, wherein each ply comprises a STF-treated textile base. The feature of a glove having a multi-ply STF-treated textile base may be used in conjunction with any type of glove design, including gloves not having only some or none of the other features described herein.
Any of the glove embodiments described herein may further comprise a barrier that is resistant to bloodborne or other bodily-fluid-borne pathogens, such as but not limited to viral or bacterial pathogens (referred to hereinafter generally as a “pathogen barrier”). The pathogen barrier may comprise a coating on one or more of the plies of the palmar portion and the back portion, such as a coating material selected from the group consisting of: silicones, polyurethanes, fluoropolymers, and natural or synthetic latexes. In one embodiment, the pathogen barrier coating overlaid on the STF-treated textile base may be a product of a blade coating process.
In some embodiments, the pathogen barrier may comprise an outer layer in the form of a laminate, such as a laminate over a seamed two-ply palmar and back portion, all of which together may comprise an underglove component. This discrete outer layer pathogen barrier may be in addition to a separate overglove, typically made from a latex material, specifically natural rubber latex, poly(chloroprene), nitrile or, ideally, poly(isoprene), that is donned subsequently after donning the underglove.
Thus, one aspect of the invention is a glove system comprising an overglove and an underglove. The seamed two-ply palmar and back textile portions as described herein, optionally having its own pathogen barrier as described herein, may comprise the underglove. The pathogen barrier on the textile underglove permits use of a 2-glove system, rather than prior art 3-glove systems in which a cut-resistant textile glove liner is sandwiched between two rubber or synthetic rubber gloves. The 2-glove system permits improved tactile sensitivity for the wearer over 3-glove systems. In addition to the improved sensitivity resulting simply from having one fewer layer, the use of an overglove made from a stretchable material also tends to compress the underglove against the hand of the user, thereby further improving sensitivity. It should be understood, however, that gloves described herein may still be used in 3-glove systems, and that such systems may have advantages over prior art 3-glove systems.
Textiles made from low modulus materials generally have a high degree of flexibility and can be made into a comfortable glove. Low modulus yarns can easily move out of the path of a needle, however, and may not offer much puncture resistance on their own. It is desirable, therefore, to create a surgical glove made from a material that normally has a very low stiffness to allow superior tactile sensitivity and freedom of movement, but that instantaneously stiffens to provide puncture resistance when a needle contacts the fabric. One example of a material that can react to different conditions of applied stress is a shear thickening fluid (Wagner and Brady, Phys. Today, Vol. 62, p. 28, 2009, incorporated herein by reference). Shear thickening is a phenomenon that is often observed in concentrated colloidal suspensions in which the suspension exhibits a dramatic, sometimes discontinuous increase in viscosity as the shear stress is increased. A number of parameters, including the solvent viscosity, particle concentration, interparticle forces, particle size and shape determine the shear thickening behavior of concentrated suspensions (Barnes, J. Rheol., Vol. 33, p. 329, 1989; Hoffman, J. Rheol., Vol. 42, p. 111, 1998; Egres and Wagner, J. Rheol., Vol. 49, p. 719, 2005). The shear-thickening transition may be predicted for electrostatically stabilized or hard-sphere dispersions. (Maranzano and Wagner, J. Rheol., Vol. 45, p. 1205, 2001a, and Maranzano and Wagner, J. Chem. Phys., Vol. 114, p. 10514, 2001). Various rheological and scattering experiments have been used to study the mechanism of shear-thickening and associated suspension microstructure in different systems (D'Haene et al., J. Colloid Interface Sci., Vol. 156, p. 350, 1993; Bender and Wagner, J. Colloid Interface Sci., Vol. 172, p. 171, 1995; Egres et al., J. Rheol., Vol. 50, p. 685, 2006; Lee and Wagner, Ind. Eng. Chem. Res., Vol. 45, p. 7015, 2006; Kalman and Wagner, Rheol. Acta., Vol. 48, p. 897, 2009). Stokesian dynamics simulations have also been used to investigate the behavior of shear-thickening suspensions (Bossis and Brady, J. Chem. Phys., Vol. 91, p. 1866, 1989; Foss and Brady, J. Fluid Mech., Vol. 407, p. 167, 2000; Catherall et al., J. Rheol., Vol. 44, p. 1, 2000). All of the foregoing citations in this paragraph are hereby incorporated by reference.
The above-referenced studies have demonstrated that shear-thickening occurs due to hydrodynamic clustering of particles accompanied by very large lubrication forces. A material in the shear-thickened state is resistant to flow and is capable of dissipating large amounts of energy. Shear-thickening fluids have properties that have been found useful in the design of dampers (US Published Patent Application 2004/0173422 by Deshmukh and McKinley), impact resistant composites and advanced body armor (U.S. Pat. No. 7,226,878; No. 7,498,276 and No. 7,825,045 to Wagner and Wetzel; Lee et al., J. Mat. Sci., Vol. 38, p. 2825, 2003; Decker et al., Comp. Sci. Tech., Vol. 67, p. 565, 2007, all of which are incorporated by reference). Multi-layer Kevlar® composites intercalated with shear-thickening fluid have been shown to have increased resistance to needles (Houghton et al., Proceedings of SAMPE 2007), but such materials are typically too thick and stiff to be ideal for use in surgical gloves.
As discussed above, one or more of the features, embodiments, or aspects described herein may be of particular utility when used in connection with composite fabric materials, such as a knit textile material that has been treated with a shear thickening fluid (STF), such as is described in U.S. Pat. No. 7,226,878; U.S. Pat. No. 7,498,276 and U.S. Pat. No. 7,825,045, all of which are incorporated herein by reference in their entirety. The addition of STF enhances the resistance of the textile to puncture. In at least one exemplary embodiment, the textile material base may comprise a nylon textile treated with STF. In other embodiments, the textile material base may comprise polyester, nylon, aramid, fiberglass, polyethylene, polypropylene, thermotropic liquid crystal polymer (such as VECTRAN®), or a combination of any of the foregoing. High-performance versions of polyester, nylon, and polyethylene may be particularly well suited for use as a textile base material.
An exemplary shear-thickening fluid comprises a concentrated colloidal suspension of ceramic particles in a polymeric solvent. The material behaves as a liquid at low shear rates/stresses, but transitions to solid-like behavior when subjected to high shear rates/stresses, such as those that are experienced at the sharp tip of a needle. By adding the STF to a textile, the fibers of the textile cannot move as freely when, for example, a needle attempts to penetrate the textile, thereby enhancing puncture resistance. The amount of STF added varies depending on the textile construction, but, for example, for a knit nylon of 100 g/m2, adding a mass of about 100 g/m2 STF will provide acceptable performance. The invention is not limited to any particular formulation or ratio of STF relative to the underlying textile.
In general, testing of puncture resistance of various textiles treated with STF measured using hypodermic and suture needles, showed higher puncture resistance than untreated textiles. An exemplary method and apparatus for puncture testing is described herein later. Using the exemplary test method it was found that the puncture resistance of knit polyester textiles treated with STF, such as the embodiment described in Example 1 herein, had a puncture resistance exceeding the puncture resistance of woven Kevlar® textiles.
One feature comprises a glove having seams that are placed in locations away from the fingertip and finger nail regions, and with a reduced number of seams in the fingertip region. Seams generally can interfere with the user's dexterity, tactile sensitivity and comfort.
While methods for seamlessly making gloves are known in the art, utilizing whole-garment knitting machines to create a garment with weft-knitting technology, the feature described in this section of the disclosure enables assembling a glove, such as via sewing, heat sealing, or adhesion, from cut textile goods of other textile constructions, such as warp knits, circular knits, wovens, or non-wovens. This design may be particularly useful in connection with composite fabric materials comprising a shear thickening fluid (STF), as described above.
In the exemplary glove design 100 shown in
In some embodiments, such as is illustrated in
The seams may be joined in a number of ways. In a first configuration, illustrated in
In any of the configurations described above, after stitching, the stitch holes, pores between the stitch holes and raw edges (such as abutted seams) may be sealed tight by taping them with a narrow strip of sealable material, as is known in the art. The seams may also or instead be stitched with meltable or fusible thread. Instead of or in addition to stitching or stitching and taping, in any of the configurations described above, the seams may be joined by any means known in the art for imparting an impenetrable seam, such as by gluing, ultrasonically bonding, laser welding, radio-frequency (RF) welding, or heat sealing by any means known in the art.
Certain embodiments may comprise a partial glove, such as shown in
In other embodiments, the glove may comprise a plurality of panels intercalated with shear-thickening fluid, wherein the shear-thickening-fluid-intercalated panels cover one or more selected sections of the wearer's hand consisting of less than all of the wearer's hand. The selected sections to be covered may be those areas most likely to be by a puncture or a cut in the application for which the gloves are designed. Thus, for example, to maximize dexterity and minimize cost, gloves, such as disposable surgical gloves, may have STF panels only in areas where needle sticks or cuts with surgical equipment are most likely to occur.
In one embodiment, the base textile, such as the textile impregnated with an STF material as described above, may comprise a multiple-bar, warp-knitted structure, composed of a multi-filament, micro-denier textured yarn. The multi-bar structure and the multi-filament yarn together produce a tightly packed, multi-layer structure that may be further compacted via a calendering process known in the art, resulting in a “calendered” textile. The calendering process may impart at least two advantages: (1) it compresses the structure to make it thinner and (2) it pushes the yarns together to further reduce the inter-yarn spaces, or pore-size.
A lap diagram corresponding to an exemplary suitable warp knit structure is depicted in
In another embodiment, the base textile such as the textile impregnated with an STF material as described above, may comprise a circular double knit composed of a multi-filament, micro-denier textured yarn. The double knit structure and the multi-filament yarn together produce a tightly packed, two-layer structure that may be further compacted via a calendering process known in the art, resulting in a “calendered” textile.
In still another embodiment, the base textile may comprise an interlock structure as is well known in the art, for example as depicted in Spencer, David J. Knitting Technology. Pergamon Press, Oxford, 1989 p. 61.
An important characteristic of an ideal textile base for STF-applications is high yarn density (the number of yarns in a unit area for both the warp and weft directions). One way to achieve this is by utilizing a micro-denier yarn. The more filaments that can be packed in the yarn structure, the better the coverage. In general, the finer the fiber, the more closely packed the fiber assembly will be in the yarn and fabric construction. This yields smaller spaces between fibers which will inhibit threat entry and contribute to better chemical absorption. In addition, the fineness or diameter of a fiber typically directly affects a fabric's handle and flexural rigidity. Very fine filaments and their resultant yarns will produce a fabric with fluid drape. Coarse filaments and their resultant yarns will produce a fabric that is more rigid. It is therefore desirable to achieve a fabric substrate constructed with a yarn engineered in such a way to maximize these characteristics that will provide an optimal base for the shear thickening fluid, an optimal barrier to penetration by the threat, and not inhibit the flexibility and tactile sensitivity of the glove. For example, embodiments of the present invention have been constructed with a 20 denier/17 filament, 30 denier/34 filament and 40 denier/68 filament yarns, and 70 denier/68 filament yarns. The invention is not limited, however, to any particular denier or filament values or combinations.
One aspect of the invention comprises a textile-based surgical glove that offers protection against mechanical aggressors, (e.g. needles, sharp bone fragments or other surgical instruments) while also providing the barrier to bloodborne or other bodily-fluid-borne pathogens, such as but not limited to viruses or bacteria, which is a requirement in a surgical glove. By incorporating both the mechanical protection and pathogen barrier in a single glove or glove liner, the glove or glove system can be thinner and lighter than prior art systems, thereby having a minimal impact on the dexterity and tactile sensitivity of the wearer. A single or double glove system is more convenient to don than a triple glove system offering comparable protection in situations where gloves may need to be rapidly donned or changed, although a triple glove system comprising one or more of the features described herein may still have substantial advantages over the prior art.
Barrier functionality may be created by coating or laminating the textile glove with an appropriate material, such as a polyurethane, silicone, fluorinated polymer, polyisoprene or natural latex. The barrier may be present on one or both sides of the textile. The barrier material is applied to the textile using a controlled process to ensure that the coating material penetrates only minimally into the textile. Such low degree of barrier penetration creates a material that retains a high degree of flexibility and dexterity when made into a glove.
A polyurethane laminate is one example of a coating that is capable of providing pathogen barrier functionality with minimal effect on flexibility. Polyurethane films are inherently flexible and elastic. Lamination of polyurethane films onto the textile may be accomplished through the use of hot melt lamination or through the use of a suitable adhesive, as is known in the art. Preliminary testing showed that thermal lamination could attach a polyurethane film to a knit polyester textile while maintaining the favorable flexural properties of the base textile. A schematic of the thermal lamination process is shown in
An alternative exemplary embodiment comprises a silicone elastomer coating bound onto a knit Nylon textile. This coating may be applied using a method such as blade coating, as is known in the art. One such blade coating configuration, a blade-over-roll, is shown in
After producing a textile by any of the processes described above, or by others known in the art, the glove may be assembled by a cut-and-sew process or by using a heat/ultrasonic/RF sealing method as is known in the art. Materials such as seam tapes may be used to seal the seams of a sewn glove. Heat-sealed seams may be made water/pathogen proof by selecting the appropriate coating polymer (typically polyurethane) and controlling the heat sealing process to ensure the seams are completely sealed.
As noted previously, mechanical protection may be provided by using an engineered, STF-treated knit textile material. To achieve the pathogen barrier functionality, a coating material or laminate layer as described above may be applied to one or both surfaces of the STF-treated textile. Exemplary coatings may comprise a silicone, polyurethane, fluoropolymer, natural or synthetic latex, or any other material that is capable of forming a pathogen barrier. The invention is not limited to any particular type of pathogen barrier material, when present. By carefully controlling the coating process, particularly the film penetration and thickness, the flexibility and comfort of the glove can be retained. As noted above, it is desirable to use a thin and light coating with a minimal degree of penetration into the textile to maximize flexibility.
An additional aspect of the invention comprises a glove system in which an additional latex or synthetic surgical glove is donned over a puncture-resistant textile glove. In one embodiment, the textile itself may not be coated with a pathogen barrier, such that the outer glove provides primary barrier functionality. Alternatively, the textile glove may be worn in between two latex gloves to provide additional barrier protection. In the multiple glove systems, the outermost glove may be of a size that permits the outer glove to apply a compressive force when donned. The compressive force will act on the textile glove to urge a close fit with the wearer's hand. The compression will also act in a manner that may decrease spacing between yarns in the textile and therefore favorably impact the tactility and puncture resistance offered by the glove system.
As noted herein above, adding a STF to a textile may greatly enhance puncture resistance of an article, such as a glove. Such puncture resistance, however, is dependent on the needle impacting a fiber. All fabrics, including non-STF-treated fabrics, have some portion of void space between fibers/yarns due to the knit construction. It may therefore be relatively easy for a needle to puncture a single ply textile material in some configurations, as the tip of the needle can slip in between fibers/yarns before the thicker portions of the needle are fully engaged by the protective textile. If a needle impacts in this void space it is possible for the tip to slip through unhindered and possible cause injury. Accordingly, the lack of spatial homogeneity in a knit or woven textile means that there is a chance that the sharp needle point will find a small void space in the knit/weave and will not engage the fibers. The void space between fibers/yarns may be referred to as a window, and the ability to penetrate such a window may be referred to as “windowing.”
A multi-ply construction is used to counteract the ability of a small needle tip to penetrate the textile with minimal force. A second or subsequent layer of the textile maintains a barrier even if the first layer is defeated via a void. Preferably, the layers of the textile may be assembled such that the orientation of the fabric in the top layer is rotated, such as at an angle of 90 degrees, relative to the bottom layer. The 90-degree rotation minimizes the chance of the holes in each layer aligning because of some pattern of the knit construction or direction.
For example, assuming a knit protective textile with small holes distributed over 5% of its surface and a probability that a needle is equally likely to contact any region on the surface, the needle is likely to penetrate with minimal resistance 5% of the time, for a single ply. With two plies, the chance of hitting no fibers on the way through the textile is reduced to 0.25%, particularly if the orientation of the weave in adjacent plies are 90 degrees rotated relative to one another to minimize the possibility of the windows in one ply aligning with the windows in the other. With denser fabric constructions having less void space, a larger relative reduction in the incidence of unhindered puncture is expected.
A two-ply STF-textile composite is more flexible than the traditional puncture-resistant materials and does not interfere with tactile sensitivity. Accordingly, one embodiment comprises a glove constructed from two layers of knit Nylon textile treated with shear-thickening fluid. The nylon textile is lightweight, thin and flexible and thus allows for good dexterity and tactile sensitivity. Knit nylon does not have significant resistance to puncture by a surgical or hypodermic needle, however, so adding a shear-thickening fluid increases the puncture resistance of the glove. While a two-ply construction with each ply offset 90 degrees from one another may be adequate to impart a desirable amount of additional protection while maintaining flexibility for most applications, the invention is not limited to any particular number of plies or orientation of those plies.
A two-point discrimination test administered to surgeons showed that 2-ply gloves as described herein scored markedly better than published scores for other puncture resistant products. Puncture testing performed on an artificial finger, such as using the exemplary puncture testing apparatus referenced herein previously, showed that the puncture resistance of the 2-ply construction showed substantial increase over a 1-ply construction. More importantly, the minimum force required to puncture the material (i.e. the force when a needle slips through the void space) for the two-ply construction increased from effectively zero for the one ply textile, to a value exceeding the one-ply average.
The plies may be joined at the seams in a number of ways, such as those shown in
Another aspect of the invention comprises a multi-glove system comprising at least an underglove and an overglove. The underglove preferably comprises a textile or textile-composite material that is engineered to have enhanced resistance to puncture in the form of a glove or partial glove having one or more of the various features described above. The underglove component may comprise a full glove or a partial glove covering less than all the wearer's hand, as described above. The underglove is worn underneath a conventional latex or non-latex surgical glove, which may or may not be attached to the underglove. Optionally, another conventional latex or non-latex surgical glove may be worn underneath the textile or textile-composite underglove component.
A textile was made from a 70 denier polyester yarn with 68 filaments per yarn. The textile was an interlock knit prepared on a 42-gauge machine with the final knit having 62 wales/inch and 58 courses/inch. An exemplary material, procured from Gehring Textiles, Garden City, N.Y., having the physical properties listed in Table 1, was subjected to a standard calendering process known in the art and conducted by Gehring Textiles to compact the knit. The calendering process reduced the thickness of the textile from the original 0.44 mm to 0.30 mm without altering the weight. A shear thickening fluid, described in more detail below, was then applied to the calendered fabric.
The shear thickening fluid was prepared by dispersing amorphous, spherical, silica particles in 200 average molecular weight polyethylene glycol. The particles were Nan-O-Sil silica, supplied by Energy Strategy Associates of Old Chatham, N.Y. The particles were dispersed to 60 wt % in the suspension. The rheology of the suspension was measured using an AR2000 rheometer from TA Instruments with a 40 mm 2 degree cone and plate geometry. Rheological measurements showed that the suspension shear thickened at an applied shear stress of approximately 30 Pa.
Silica/polyethylene glycol shear thickening fluid was intercalated into the knit textile using the following process. The shear thickening suspension was diluted in ethanol at a ratio of 1.05 grams of ethanol to 1 grams of suspension. Pieces of interlock knit textile were dipped into an agitated bath containing ethanol-diluted shear thickening fluid for 1 minute. The textile was removed from the bath and run through a set of nip rollers to remove excess liquid. Textile samples were then hung in a convection oven at 60° C. for one hour to remove the ethanol. Samples were stored in a sealed bag with desiccant to maintain dryness.
Puncture resistance was measured on an Instron 4021 load frame controlled by a computer with Bluehill 2 software. Puncture probes were 21 gauge Precision-Glide™ hypodermic needles manufactured by Becton-Dickinson, part number 305167. Needles were attached to a +/−100N load cell connected to the load frame. Test samples were mounted on a custom sample holder consisting of a steel base plate upon which was placed the elastic conductive backing material. Samples were placed between the conductive backing and a top plate with 1 cm holes at the puncture test sites. The top plate was secured using four bolts located at 0, 90, 180 and 270 degree positions. A puncture detection circuit with two test leads, such as described herein later, was wired to a 25-pin D-plug that connected to the “Strain 1” channel on the load frame. The apparatus provides an electronic indication when barrier properties are lost during puncture testing. The electronic puncture detection circuit provides a clear indication of when a test material has been punctured, even if the puncture point is not noticeable on a force-displacement curve. A schematic illustration of the puncture detection circuit is shown in the circuit diagram of
An exemplary testing apparatus is shown in
To perform a puncture test, the test specimen 70 was placed on top of the conductive backing 45. Through the electrical connection 50, the computer processor 60 programmed with appropriate software was used to control the load frame to lower the crosshead 41 and attached puncture probe 44 into the specimen at a controlled rate. Connection 50 also enables the computer 60 to record the load cell and puncture detection circuit signals to produce curves of force and detection circuit signal as a function of probe displacement.
The elastic conductive backing was a silicone rubber containing 25 wt % milled carbon fibers (Fortafil 341 from TohoTenax). The filled rubber was prepared by dispersing the carbon fibers in the base poly(dimethyl siloxane) of a two-part Sylgard® 184 kit manufactured by Dow-Corning. The fiber filled base was degassed under vacuum. Curing agent from the Sylgard® kit was added in the ratio of 1 part curing agent to 10 parts base and was throughly mixed into the silicone base/carbon fiber. The mixture was then gently poured into a dish-shaped mold and was degassed under gentle vacuum. The filled silicone rubber was cured at 70° C. for 2 hours. Electrical resistance was measured by gently pressing the leads of a digital multimeter into the surface of the carbon fiber PDMS at a spacing of approximately 2 cm. The measured resistance was approximately 300 ohm.
Puncture testing was performed on the knit textile with the textile sample placed between two pieces of latex to simulate the actual clinical use conditions in which the textile will reside between latex gloves or have an elastomeric barrier coating. Each test recorded the force and puncture probe displacement as the probe was lowered into the test specimen at a speed of 10 mm/min. The puncture force for each specimen was defined as the force measured by the load cell at the point when the puncture detection circuit attached to the Strain 1 channel showed a jump in signal. Tests were performed on a single textile layer and with two textile layers, with the layers offset by 90 degrees. Table 2 summarizes the average puncture forces from 12 puncture tests on the various configurations. The puncture resistance of latex double gloving is shown for comparison. The results in Table 2 demonstrate that the textile provides more puncture resistance than conventional gloves. However, the performance increases with STF-intercalated fabrics are even more impressive. The glove system with a single layer of STF-textile is five times more resistant than conventional gloves. With two layers of STF-textile, the protective glove system is over 11 times more resistant to needle puncture.
A two-point discrimination test was administered with a Disk-Criminator apparatus to measure the tactile sensitivity offered by the various glove configurations. The methodology of such a test is described in Fry et al., “Influence of Double-Gloving on Manual Dexterity and Tactile Sensation of Surgeons,” J. Am. Coll. Surg., 210: 325-30, March 2010, incorporated herein by reference. The results of the two-point discrimination test are shown in Table 2. All of the glove configurations incorporating the knit textile offered a level of tactile sensitivity that was the same as the double latex gloves. The tactile sensitivity offered by previously marketed FingGuard® and LifeLiner® puncture-resistant products (reported in Woods et al., “Effect of Puncture Resistant Surgical Gloves, Finger Guards, and Glove Liners on Cutaneous Sensibility and Surgical Psychomotor Skills,” J. Biomed. Mater. Res., Vol. 33, p 47, 1996) are shown for comparison, although the data for these products may have been recorded by a slightly different method than the others. The lack of difference among the other examples above, however, demonstrates that glove embodiments tested and described herein are essentially equivalent to double gloving with respect to tactile sensitivity. In contrast to the exemplary textile manufactured as described above, the prior art puncture resistant materials severely compromised tactile sensitivity.
While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention. In particular, to the extent that various features have been described herein, it should be understood that any one feature may be provided alone with other features known in the art or combined with any or all of the other features described herein, in any combination or permutation.
Number | Date | Country | Kind |
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61321720 | Apr 2010 | US | national |
61321726 | Apr 2010 | US | national |
61321732 | Apr 2010 | US | national |
This application claims priority from U.S. Provisional Application Ser. No. 61/321,726, titled “GLOVE DESIGN FOR MAXIMIZING DEXTERITY, TACTILITY, AND COMFORT,” filed Apr. 7, 2020; U.S. Provisional Application Ser. No. 61/321,732, titled “PUNCTURE AND/OR CUT RESISTANT SURGICAL GLOVE HAVING VIRAL BARRIER PROPERTIES,” filed Apr. 7, 2020; and U.S. Provisional Patent Application Ser. No. 61/321,720, titled “ELECTRICAL DETECTION APPARATUS FOR DETERMINING THE PUNCTURE FORCE REQUIRED TO BREACH A BARRIER MATERIAL,” filed on Apr. 7, 2010, all of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US11/31546 | 4/7/2011 | WO | 00 | 2/19/2013 |