Tear-resistant and pilling-resistant fine knitted clothing

Abstract

This invention relates to knitted fabrics using a specific combination of UHMWPE fibers and elastic fibers (e.g., spandex) that can be used to make tear-resistant, transparent socks or similar garments. The knitted fabrics exhibit tear-resistant and antimicrobial properties. Detailed information is provided to prevent pilling and bald spots during use. Variants of the knitted fabrics can be used in sportswear.

Description

[0001] This application is a divisional application of application number 201880042106.4, application date June 26, 2018, and invention name “Tear-resistant and pilling-resistant fine knitted garments”.

[0002] Citation of Related Applications

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 524,986. Technical Field

[0004] The present invention relates to a knitted fabric for making tear-resistant transparent hosiery or similar garments, which uses a specific combination of UHMWPE fibers and elastic fibers (such as spandex). Background Art

[0005] Sheer hosiery, whether in the form of sheer tights, stockings, or pantyhose, has traditionally been very fragile and prone to tearing.

[0006] The transparency of hosiery is measured in denier. Denier is a unit of measure for the linear mass density of a fiber, expressed in grams per 9,000 meters of fiber. Transparency refers to how well light can pass through a hosiery garment. Transparency is determined by the denier of the fiber used to make the hosiery garment. Hosiery garments produced using lower denier measurements, ranging from 1 to 30, appear transparent, allowing the most light to pass through. Hosiery produced using fibers with deniers between 31 and 100 are described as translucent to nearly opaque in appearance. Deniers above 100 no longer produce transparent hosiery and do not allow light to pass through.

[0007] Traditional fibers used for hosiery (i.e., nylon, Lycra(TM), polyester) have very low tensile strength, which results in very weak garments, especially at lower deniers. Sheer hosiery products (30 denier and below) made with these fibers are very fragile. They are easily torn by hands, feet, or long fingernails and are generally considered disposable. Tensile strength is the maximum tensile stress that can be applied to a material before it no longer has elasticity and is measured in Pascals (Pa) or Newtons per square meter (N / m 2 units for measurement.

[0008] There is a need for a commercially viable transparent elastic knit fabric that does not readily tear.

[0009] Previous attempts have produced form-fitting garments with high cut resistance. US 2010 / 0050699 to Kolton discusses the use of high-performance fibers, one of which is UHMWPE, in combination with suitable high-performance nylons to produce several protective garments, including socks. However, this application focuses on the production of protective garments and does not address the challenges of producing low-denier products or high-gauge knits, or the production of colored materials when using UHMWPE. Summary of the Invention

[0010] The present invention relates to a tear-resistant, non-pilling knit fabric that is lightweight, flexible, and has improved durability compared to traditional knit fabrics used for socks and sportswear. The knit fabric can be produced in a variety of colors. When applied to sheer socks, the present invention improves the durability and moisture-wicking properties of traditional sheer socks. It exhibits tear resistance and antibacterial properties while maintaining the same transparency, flexibility, pilling resistance, and overall weight as traditional sheer stockings.

[0011] In the transparent hosiery space, the present invention's 32-gauge knits with an apparent denier of 30 or less are suitable for garments such as transparent tights, stockings, or pantyhose. When applied to non-transparent knits with a total denier of 18 or more, ranging from 30 to 220, the resulting knits are more durable and lighter than traditional knits, with the added benefit of being antimicrobial.

[0012] According to the present invention, a knitted fabric is provided comprising at least one UHMWPE fiber and at least one spandex fiber, wherein the at least one UHMWPE fiber is colored using a non-additive method, and the at least one UHMWPE fiber and the at least one spandex fiber are plated or used. In one aspect of the invention, the at least one UHMWPE fiber has a denier of 30 or less, the at least one UHMWPE fiber is twisted, the at least one spandex fiber is a transparent spandex fiber having a denier of 5 to 100, and the knitted fabric has a gauge of at least 32, resulting in a total visible denier of 30 or less. In another aspect of the invention, the at least one UHMWPE fiber has a denier of 20 to 30. In another aspect of the invention, the at least one spandex fiber is a transparent spandex fiber having a denier of 5 to 10. In another aspect of the invention, the at least one spandex fiber is a transparent spandex fiber having a denier of 40 to 70.

[0013] In yet another aspect of the invention, there is only one UHMWPE fiber and only one spandex fiber.

[0014] In another aspect of the invention, the UHMWPE fiber has a twist per inch (TPI) of 4 to 52. In another aspect of the invention, the UHMWPE fiber has a TPI of 6 to 20. In another aspect of the invention, the UHMWPE fiber has a TPI of about 20. In another aspect of the invention, the UHMWPE fiber has a TPI of about 12.

[0015] In another aspect of the present invention, the at least one UHMWPE fiber and the at least one spandex are used, and the at least one UHMWPE fiber and the at least one spandex have a twist of 100 to 450 twists per meter. In another aspect of the present invention, the at least one UHMWPE fiber and the at least one spandex have a twist of 1000 to 1500 twists per meter. In another aspect of the present invention, the at least one UHMWPE fiber and the at least one spandex have a twist of approximately 1500 twists per meter.

[0016] In another aspect of the invention, tights, stockings or pantyhose comprising the knitted fabric of the invention are provided.In another aspect of the invention, tights, stockings or pantyhose are treated with wear pads in high wear areas.

[0017] In another aspect of the invention, the at least one UHMWPE fiber has a denier of 10 to 100, the at least one spandex fiber has a denier of 20 to 140, the gauge of the knitted fabric is at least 18, and the total visible denier of the resulting knitted fabric is 30 or greater. In another aspect of the invention, the at least one UHMWPE fiber has a denier of 30 to 50, and the at least one spandex fiber has a denier of 40 to 100.

[0018] According to the present invention, a knitted fabric comprising at least one UHMWPE fiber and at least one spandex is provided, wherein the at least one UHMWPE fiber is twisted, the at least one UHMWPE fiber is colored using a non-additive method, and the at least one UHMWPE fiber and the at least one spandex may be plated or used. In one aspect of the invention, the at least one UHMWPE fiber has a denier of 30 or less, the at least one spandex is a transparent spandex having a denier of 5 to 100, the knitted fabric has a gauge of at least 32, and the resulting knitted fabric has a total visible denier of 30 or less. In another aspect of the invention, there is only one UHMWPE fiber and only one spandex.

[0019] According to the present invention, there is provided a knitted fabric comprising at least one UHMWPE fiber and at least one spandex, wherein the at least one UHMWPE fiber is twisted, the at least one UHMWPE fiber is colored using a non-additive method, the at least one UHMWPE fiber and the at least one spandex are used with about 1500 twists per meter, the at least one UHMWPE fiber has a denier of 20 to 30, and the at least one spandex is transparent, and the denier of the resulting knitted fabric is less than 30. In another aspect of the invention, there is only one UHMWPE fiber and only one spandex. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is described with reference to the following drawings:

[0021] Figure 1 is an illustration of an exemplary embodiment of a seamless pair of transparent leggings featuring wear pads on the heel and thigh;

[0022] Figure 2 are illustrations of some other possible transparent embodiments: stockings, pantyhose;

[0023] Figure 3A This is a photo of untwisted white UHMWPE at a magnification of 225 times;

[0024] Figure 3B This is a photograph of twisted black UHMWPE with 12 TPI, which is magnified 225 times;

[0025] Figure 4 It’s a photo of pilling;

[0026] Figure 5A This is a photo of black-plated twisted UHMWPE and black spandex, magnified 65x.

[0027] Figure 5B This is a photo of black-plated twisted UHMWPE and black spandex, with a magnification of 225 times;

[0028] Figure 6 yes Figure 5A and 5B Photo of a bald spot in a knitted fabric, magnified 65 times. DETAILED DESCRIPTION

[0029] As used herein, the term "transparent" refers to garments having an apparent denier of 30 or less. This is considered the generally accepted industry metric for transparent garments.

[0030] The term "denier" as used herein refers to a weight unit indicating the fineness of fiber filaments. It can be measured in grams per 9000 meters of fiber.

[0031] The term dtex refers to another weight unit that indicates the fineness of fiber filaments. It can be measured in grams per 10,000 meters of fiber.

[0032] The term "tensile strength" as used herein relates to the durability of a garment and is measured by the maximum stress, which is the maximum stress a material can withstand when stretched or pulled before breaking. It is measured as force per unit area and can be expressed in grams-force (gf) and centinewons (cN) per dtex.

[0033] As used herein, the term "elongation" refers to the stretching of individual fibers and composite yarns that results in the elasticity of the final embodiments of the present invention. Elongation is measured as a percentage relative to the starting length.

[0034] As used herein, the term "fiber" refers to a single-source base material composed of one or more filaments.

[0035] As used herein, the term "filament" refers to a single thread of material, which may be a fiber by itself or may be combined with other filaments to form a multifilament fiber.

[0036] As used herein, the term "pill" refers to a surface defect that occurs in hosiery when individual fibers or filaments become caught and pulled away from the rest of the knitted fabric. Pilling is considered unsightly and may render a pair of sheer hosiery unusable.

[0037] As used herein, the term "knitted fabric" refers to a fabric made by combining one or more fibers on a flat knitting machine or a circular knitting machine.

[0038] The term "gauge" refers to the number of needles on a knitting machine. High-gauge knitting machines (32 gauge and above) are needed to produce sheer hosiery, such as sheer tights, stockings, and leggings, while lower-gauge knitting machines (18 to 32 gauge) are used to produce heavier garments, such as leggings, bodysuits, socks, shirts, and other activewear. Gauge is also used to refer to the knit fabric produced by a machine: in other words, a knit fabric made on a 32-gauge machine is a 32-gauge knit.

[0039] The term "end count" is the number of fiber bobbins fed into a given knitting machine used to produce the present invention.

[0040] The term "UHMWPE" stands for ultra-high molecular weight polyethylene fiber, also known as high modulus polyethylene (HMPE) or high performance polyethylene (HPPE).

[0041] The term "colored UHMWPE" refers to UHMWPE that has been colored (made non-white) by non-additive coloring methods.

[0042] The term "plating" as used herein refers to the technique of knitting two fibers in two different layers together. Although knitted with the same stitch, one fiber remains behind, behind the front yarn.

[0043] As used herein, the term "serving" refers to the process of spinning two fibers together to produce a composite yarn.

[0044] As used herein, the term "apparent denier" refers to the total denier of the visible fibers used in the knitted fabric; for purposes of this application, transparent fibers are considered inconspicuous.

[0045] As used herein, the term "bulk" refers to the addition of new fibers which increases the overall apparent or non-apparent denier of the fibers.

[0046] As used herein, the term "non-additive" refers to a coloring process, typically a dyeing process, that does not increase the overall apparent or non-apparent denier of the fiber.

[0047] As used herein, the term "bald spot" refers to a defect that occurs when UHMWPE is coated with a material such as spandex (also known as elastane). This occurs when the spandex layer passes through the UHMWPE layer. This defect is more noticeable in higher gauge knits than in lower gauge knits.

[0048] As used herein, the term "wear pad" refers to the use of non-UHMWPE knit fabrics and the addition of a coating in high friction / wear areas to reduce bald spots and holes caused by knit damage. Wear pads are important in garments made from high gauge knit fabrics, as described herein, but are optional in lower gauge knit fabrics.

[0049] The term "compression" refers to garments designed to apply pressure. The compressibility factor can be measured in millimeters of mercury (mmHg).

[0050] When considering knitted fabrics for sheer hosiery, there are three key characteristics to consider: elongation, strength, and transparency. No single fiber can meet all three requirements for sheer hosiery. In addition to these key properties, knitted fabrics are also desired to be lightweight and have antimicrobial properties. In some cases, compression is also required.

[0051] UHMWPE is an extruded multifilament fiber based on a polymer with little or no elongation, yet the fiber possesses high tensile strength. Using low-denier, colored UHMWPE can create transparent hosiery with significant tear resistance. The use of UHMWPE adds several advantages not found in knitted fabrics without UHMWPE: UHMWPE has a cooling effect, is lighter than traditional hosiery fibers, and possesses moisture-wicking and antimicrobial properties. These antimicrobial and moisture-wicking properties are due to UHMWPE's hydrophobic nature.

[0052] Steering Figure 1 , shows a pair of leggings 10 which would be a typical use of the present invention. Figure 2 , shows stockings 12 and pantyhose 14, which are other examples of products that can use the present invention. As described below, the application describes how to use low denier UHMWPE fibers in hosiery products, such as Figure 1 and 2 shown.

[0053] The present invention is a knitted fabric comprising two low-denier fibers. One is a spandex fiber for elongation, and the other is a high-tenacity fiber for strength. The high-strength fiber used to achieve this invention is UHMWPE. To achieve both strength and elongation in the final product, UHMWPE is combined with the spandex fiber in a manner that does not compromise the strength or elongation of the final product, as described below.

[0054] Besides UHMWPE and spandex, no other fibers are required. Other fibers would unnecessarily increase the weight and bulk of the final product or reduce the percentage of UHMWPE in the knitted fabric. A higher UHMWPE content means the final product is more durable and has enhanced antimicrobial properties. Generally, any hydrophilic fibers are undesirable, except when spandex (also known as elastane) or alternative spandex fibers are used to achieve elongation.

[0055] Knitted fabrics for transparent applications are knitted on high-gauge knitting machines (typically 32 gauge and above). When knitting UHMWPE on high-gauge knitting machines designed for transparent hosiery, the applicants discovered that this multifilament fiber has a greater tendency to pill than monofilament conventional hosiery fibers. To address this issue, UHMWPE used in transparent hosiery applications may be twisted before being knitted with stretch fibers (such as spandex).

[0056] Figure 3A This is a photo of untwisted UHMWPE. Figure 3B This is a photo of twisted UHMWPE. Twisting is needed to hold the filaments together, increase strength and reduce pilling. Figure 3A , there is a 20-ply, 30-denier white UHMWPE fiber 20 that is not twisted. Figure 3B , there is a 20-ply, 30-denier black UHMWPE fiber 22 twisted at 12 twists per inch (TPI). Figure 4 shows the pilling that can occur in knitted fabrics when using untwisted UHMWPE, e.g. Figure 3A As shown. Figure 4 The knitted fabric 40 comprises a group of untwisted UHMWPE fibers coated with untwisted UHMWPE fibers. After use, pilling 46 is formed, in which individual fibers have been pulled away from the rest of the knitted fabric.

[0057] The twisting of the fibers can be performed on several types of twisting machines known in the art. To maintain strength, the twist per inch (TPI) should not be too high, as this will reduce the strength of the UHMWPE fiber and may produce unbalanced fibers. In a preferred embodiment, the TPI of 30 denier UHMWPE is 4 to 20 TPI. In another embodiment, the TPI of the UHMWPE is 6 to 15. In a preferred embodiment, the TPI of the UHMWPE is 15. In another preferred embodiment, the TPI of the UHMWPE is 12.

[0058] Pilling is not an issue in the lower gauge knits of 18 to 28. These gauges are used for non-transparent applications (such as sportswear products), so twisting is optional in these applications.

[0059] Experiments have shown that simply blending UHMWPE and spandex, while producing a knitted fabric with high elongation, results in a loss of UHMWPE's strength properties, thereby reducing the knit's tear resistance. Composite yarns made with air-set technology are unsuitable for use with sheer hosiery due to increased pilling of the UHMWPE. Blending the two fibers in conventional knitted fabrics without plating the knitted fabric or fusing the two fibers into a single yarn can compromise the tensile strength of the UHMWPE in the composite yarn.

[0060] Experimentation has established two methods that can be used to effectively achieve stretch in the final knitted fabric without compromising the strength properties provided by UHMWPE: plated knit structures or fused yarns.

[0061] For our purposes, coating refers to knitting UHMWPE with elastic yarn or spandex. During the coating process, UHMWPE fibers are applied to every course of the knitted fabric, and spandex can be applied to every other course. After the knitting process, the knitted structure will have the UHMWPE yarn more prominently exposed on one side (intended for the exterior of the knitted garment), while the elastic yarn (spandex) is exposed on the other side (intended for the interior of the knitted garment). This structure features both UHMWPE yarn and elastic yarn (spandex) knitted throughout the entire coated knit fabric. Figure 5A 5A (65x magnification) and 5B (225x magnification) show an embodiment of a plated knitted fabric 50 with black UHMWPE 52 and black spandex 54. Figure 5B , it can be seen that the UHMWPE 52 is plated onto the spandex 54 while still being connected at each stitch.

[0062] The second approach is to use a "fused" yarn, where two fibers are twisted into one yarn. Twisted UHMWPE can be used with raw spandex (or other stretch fibers) in deniers of 5 to 100 using conventional covering methods to make composite yarns. In a preferred embodiment, the twist of the conventional spandex covering with UHMWPE should be in the range of 100-4500 twists per meter. Higher twists per meter may be required. The increased twist in the conventional covering ensures greater stretch in the final product and increases durability in the final knitted fabric as this will result in a larger surface area of UHMWPE reinforcing the spandex (or other stretch fibers). The applicant's experimental data indicates that UHMWPE fibers are difficult to cover conventionally, and therefore, the optimal twist range has been found to be 1000-1500, with 1500 twists per meter shown in the most preferred embodiment.

[0063] In coating or using fused composite yarns, higher denier spandex ensures greater compression benefits for the end user. For compression applications, the total compression should be 15-20 mmHg or higher. The compression level can be adjusted upward by increasing the denier of the specific stretch material used in this example.

[0064] One of UHMWPE's major limitations, besides its lack of elongation, is its inability to be dyed. Not only is it non-porous and unsuitable for most traditional dyeing techniques, it also is unacceptable to most coatings and, until recently, could only be manufactured in white. For the hosiery and similar apparel markets, where black and nude colors are most desirable, white is not a commercially desirable color.

[0065] A common method of adding color to UHMWPE is to cover it with another colored material through conventional covering or knitting methods. For the purpose of making transparent hosiery, these methods are not feasible because they increase the bulk of the warp fiber denier, thereby increasing the base yarn denier to over 30 denier, which is unacceptable.

[0066] The UHMWPE used in this invention is in the desired color of the final product and is colored using a non-additive coloring method. Non-additive refers to coloring the UHMWPE using a method that does not increase the volume or denier of the UHMWPE. Two non-additive coloring methods are the addition of dyes during extrusion or supercritical CO2 dyeing (details of which are beyond the scope of this invention). Colored UHMWPE produced using non-additive methods (referred to herein as "colored UHMWPE") has only recently become available, particularly in deniers below 100.

[0067] Of particular concern with transparent UHMWPE knits produced on high gauge machines is that the stretch fiber layer (e.g., spandex) may wear away before the UHMWPE layer, resulting in a patch with a lower denier and elasticity than the surrounding knit. This defect is referred to in the remainder of this application as a "bald spot." Blends of UHMWPE with stretch fibers are particularly susceptible to this because (i) as mentioned above, UHMWPE is particularly strong and resistant to tearing or other wear or failure; (ii) the UHMWPE can rub against the stretch fibers, wearing them away, and (iii) external forces applied to the knit can erode the stretch fibers while generally not damaging the UHMWPE. Wear of the stretch fibers is aesthetically undesirable and can cause structural problems in the garment due to localized loss of elasticity. Figure 6 , from Figure 5A and 5B The knitted fabric 50 has bald spots 56 where the spandex 54 has worn away.

[0068] Using only transparent stretch fibers, such as clear spandex, can address the bald spot problem. Even if the stretch fibers fray, the difference in denier compared to the surrounding knit fabric is minimal. However, using transparent stretch fibers does not address the localized elasticity loss. Transparent spandex also has the highest tensile strength among spandex fibers, so using transparent spandex increases the durability of the final knit fabric.

[0069] Bald spots can also be addressed by fusing colored UHMWPE with stretch fibers (e.g., spandex) rather than plating. Tests have shown that fused colored UHMWPE and stretch knits (using post-use stretch fibers) produce significantly fewer bald spots than plated knits and have less of an impact on the knit's elasticity in the affected areas than plating. (Fusing colored UHMWPE with stretch fibers (e.g., spandex) also has the beneficial effect of reducing pilling.)

[0070] Even if the bald spots are not noticeable, or are reduced by using clear spandex in the coated knit or directly with the UHMWPE, any remaining bald spots will result in a separate loss of elasticity. To address this issue, wear pads can be integrated in areas such as the inner thighs, feet of pants or stockings where frequent wear is expected, thereby increasing structural support. As used herein, wear pads refer to non-UHMWPE knits and added coatings that are integrated into embodiments to prevent or at least delay bald spots. Figure 1Wear pads 60 are located on the heels of the leggings 10, while wear pads 62 are located on the thighs of the leggings 10. In a preferred embodiment, 70-denier nylon fiber and 40-denier spandex fiber are knitted on a 28-gauge machine to create inner thigh wear pads, which are then sewn onto the legs of leggings made from the knitted fabric of the present invention. In the same embodiment, the heels are dipped in a nitrile polymer coating to create wear pads on the feet. In another preferred embodiment, 70-denier nylon fiber and 40-denier spandex fiber are knitted on a 28-gauge machine and then sewn onto the feet of a pair of leggings to create wear pads for the feet and heels. Wear pads made from fibers and polymers do not have the same strength, transparency, or antimicrobial properties as the UHMWPE knitted fabric of the present invention, so they should only be used where protection from wear is needed. Wear pads are preferred in high-gauge knitted fabrics but optional in lower-gauge knitted fabrics, where bald spots are more likely to occur.

[0071] In the present invention, three types of wear pads are preferably used that use non-UHMWPE stretch fibers or polymers: 1) polymers that are applied as a coating to high wear areas by methods such as spraying or dipping; 2) wear pads that are integrated into the product by seamless knitting; 3) wear pads that are integrated using a cutting and sewing method.

[0072] When knitting into a product, to maintain strength at the seam, the wear pad can be moved in and out, first adding the wear fiber to the existing knit and then moving the UHMWPE out of the knit. Due to the low melting point of UHMWPE, the use of heat-based adhesive wear pads is not recommended.

[0073] The present invention can be produced on circular, flat, or warp knitting machines. To produce knitted fabrics of fiber light enough for socks, the knitting machines used should be size 32 or higher. To produce knitted fabrics suitable for sportswear, such as leggings, tights, socks, and shirts, machines of size 18 or higher should be used.

[0074] Where stitching is required in the final assembly of a garment, UHMWPE-based threads should be used to ensure these are not weak points in the durability of the product.

[0075] Although the above description focuses on the application of the present invention in transparent hosiery, the combination of UHMWPE and elastic fiber (e.g., spandex) can also be effectively applied to non-transparent products such as semi-transparent to opaque hosiery and sportswear. To achieve non-transparent knitting, the total denier of the base fiber used in the knitted fabric should exceed 30, or the knitted fabric should be produced on a knitting machine with a size of 32 or less.

[0076] Sportswear made from knitted fabrics of UHMWPE and stretch fibers such as spandex offers advantages over conventional sportswear, notably greatly enhanced strength (for example, it is difficult to pierce a T-shirt made from knitted fabrics of UHMWPE and spandex), light weight (especially relative to its strength), and antimicrobial properties.

[0077] Using a lower gauge knit will eliminate or make less noticeable the pilling and bald spot problems encountered with clear UHMWPE and high gauge stretch fiber (such as spandex) knits.

[0078] A knitted fabric can be created by using more than one UHMWPE fiber and / or more than one spandex fiber. A knitted fabric can be made using more than one UHMWPE fiber and / or more than one spandex fiber.

[0079] In one embodiment, when used for transparent hosiery or similar garments, the knitted fabric can be made using a UHMWPE of 30 denier or less and a transparent spandex fiber exhibiting an elongation of 30% or greater at a denier of 5 to 100, with the total visible denier of the knitted fabric not exceeding 30, knitted together on a knitting machine of 32 gauge or higher. The UHMWPE used can be fused or plated with the spandex fiber, which is a more preferred embodiment because it reduces the appearance of bald spots. In a preferred embodiment, the UHMWPE suitable for transparent applications of the present invention is a UHMWPE fiber of 10-30 denier. A more preferred embodiment is 20-30 denier. In a preferred embodiment, the spandex suitable for transparent applications of the present invention is a transparent spandex of 5-10 denier. A more preferred embodiment is 40-70 denier. The spandex used is preferably transparent.

[0080] In another embodiment, for non-transparent applications, such as translucent to opaque hosiery and athletic apparel, a UHMWPE and a spandex exhibiting greater than 30% elongation can be used to prepare the aforementioned knitted fabric, the total denier of which is between 30 and 220 denier, knitted together on an 18 gauge or higher knitting machine. For non-transparent applications, the UHMWPE used can be fused or plated with the spandex, neither of which results in noticeable bald spots. In one embodiment, the UHMWPE suitable for the non-transparent applications of the present invention is a 10-100 denier UHMWPE fiber. Another preferred embodiment is a 30-50 denier UHMWPE fiber. In one embodiment, the spandex suitable for the non-transparent applications of the present invention is a 20-140 denier spandex fiber. A more preferred embodiment is a 40-100 denier spandex fiber.

[0081] The minimum elongation of the spandex should be 30% or greater. In preferred embodiments, the spandex used exhibits an elongation greater than 100%, more preferably greater than 400%. The spandex found to be most effective for the purposes of the present invention is spandex. Other alternative spandex materials can be made from polypropylene, polyester, or nylon.

[0082] The UHMWPE used for testing exhibited a tensile strength of ≥40 cN / dtex and an elongation of ≤3.5%. Unless otherwise stated, the spandex used for testing (transparent spandex) exhibited an elongation exceeding 400%.

[0083] The following examples were evaluated by manual testing for strength, manual testing for pilling and balding, and abrasion testing.

[0084] The strength of knitted fabrics was assessed using a manual test. In this test, the end of the thumb is pressed as hard as possible against the fabric in an attempt to create a hole. In a successful test, no hole is created. In a failed test, the thumb penetrates the fabric.

[0085] Pilling and bald spots were evaluated by manual testing and abrasion testing. The manual pilling test was performed by placing a sharp object (such as a diamond ring) against the knitted fabric while it was stretched. In a successful test, no filaments were pulled out of the knitted fabric and no balls were produced. The manual test was performed by repeatedly placing a blunt object (such as a pen) against the knitted fabric while it was stretched to test for bald spots. This repetitive action breaks the spandex in the knitted fabric, leaving the UHMWPE intact. In a successful test, the bald spots were unnoticeable or reduced. In the abrasion test, the knitted fabric was worn in various embodiments and then visually inspected to look for bald spots and pilling.

[0086] In one implementation, 30 denier colored UHMWPE fiber was twisted to 12 TPI and then plated with 40 denier clear spandex on a 32 gauge knitting machine. This resulted in a very strong, stretchy, transparent knit fabric with a visible denier of no more than 30, with reduced elasticity compared to tests using 70 denier spandex. The fiber was found to have no pilling, and although bald spots did occur, they were not noticeable in the knit fabric.

[0087] In one example, a 30 denier colored UHMWPE fiber was twisted to 12 TPI and then plated with 70 denier clear spandex on a 32 gauge knitting machine. This resulted in a very strong, stretchy, transparent knit fabric with a visible denier of no more than 30, with reduced elasticity compared to tests using 40 denier spandex, and no pilling of the fiber was observed, and although bald spots did occur, they were not noticeable in the knit fabric.

[0088] In one example, 30 denier colored UHMWPE fiber was twisted to 12 TPI and then plated with 70 denier black spandex on a 28 gauge knitting machine. This resulted in a very strong, stretchy, non-transparent knit fabric (visible denier over 30) with increased elasticity compared to tests using 40 denier spandex, with no pilling observed and no noticeable bald spots in the knit fabric.

[0089] In one example, 30 denier colored UHMWPE fiber was twisted to 12 TPI and then plated with 40 denier black spandex on a 28 gauge knitting machine. This resulted in a very strong, stretchy, non-transparent knit fabric (visible denier over 30) that had reduced elasticity compared to tests using 70 denier spandex, was found to have no pilling, and had no noticeable bald spots in the knit fabric.

[0090] In one example, 30-denier colored UHMWPE fiber was twisted to 12 TPI and used with 1500 TPM, 40-denier transparent spandex, then knitted on a 32-gauge knitting machine. This resulted in a very strong, stretchy, transparent knit fabric (with a visible denier of no more than 30). In manual testing, the fiber was found to have no pilling, and the likelihood of bald spots was significantly reduced compared to plated knits with the same base fiber. When bald spots did occur, they had less impact on the knit's elasticity.

[0091] Other test embodiments of comparative examples are described in detail below.

[0092] In a comparative example, 20 denier colored UHMWPE fibers were twisted and knitted on a 32 gauge knitting machine. This resulted in a very strong, non-stretchy, sheer knit (visible denier no greater than 30) with very noticeable pull and pilling, and no visible bald spots throughout the knit.

[0093] In a comparative example, 20 denier colored UHMWPE fiber was untwisted and then knitted with 40 denier spandex cover on a 32 gauge knitting machine. This resulted in a very soft, stretchy, non-transparent knit fabric (visible denier over 30) that had very noticeable pulling and pilling, with noticeable bald spots throughout the knit.

[0094] In a comparative example, 20 denier colored UHMWPE fiber was twisted to 6 TPI and then plated with 40 denier black raw spandex on a 32 gauge knitting machine. This resulted in a very strong, stretchy, non-transparent knit fabric (visible denier over 30) that had noticeable pulling and pilling, with noticeable bald spots throughout the knit.

[0095] In a comparative example, 20-denier colored UHMWPE fiber was twisted to 9 TPI and then plated with 40-denier black raw spandex on a 32-gauge knitting machine. This resulted in a very strong, stretchy, non-transparent knit (visible denier over 30) that exhibited noticeable pulling and pilling (although less than in tests using 6-TPI UHMWPE fiber), with noticeable bald spots throughout the knit.

[0096] In a comparative example, 30 denier colored UHMWPE fiber was twisted to 12 TPI and then plated with 40 denier black raw spandex on a 32 gauge knitting machine. This resulted in a very strong, stretchy, non-transparent knit (visible denier over 30) with significantly reduced pilling and very noticeable bald spots throughout the knit.

[0097] While the foregoing description and drawings relate to certain preferred embodiments of the invention presently contemplated by the inventors, it should be understood that various changes, modifications, and adaptations known to those skilled in the art may be made.

Claims

1. A knitted fabric consisting of multifilament UHMWPE fiber and spandex, wherein: The spandex is selected from spandex and nylon fibers and has an elongation greater than 30%. The filaments of the multifilament UHMWPE fiber are twisted together, and the multifilament UHMWPE fiber with the twisted filaments is twisted around the spandex at 1,000 to 1,500 twists per meter to form a composite yarn. The composite yarn includes the multifilament UHMWPE fiber covering the spandex, wherein the multifilament UHMWPE fiber has a denier of 20 to 30, and the spandex has a denier of 40 to 70.

2. The knitted fabric according to claim 1, wherein Multifilament UHMWPE fibers have twists per inch ranging from 4 to 52.

3. The knitted fabric according to claim 1, wherein Multifilament UHMWPE fibers have twists per inch ranging from 6 to 20.

4. The knitted fabric according to claim 1, wherein The total visible denier of the knitted fabric is 30 or less.

5. The knitted fabric according to claim 1, wherein The knitted fabric has a total visible denier of 30 to 220.

6. The knitted fabric according to claim 1, wherein The knitted fabric is a knitted fabric of 32 gauge or higher.

7. The knitted fabric according to claim 1, wherein The knitted fabric is 18 to 32 gauge knitted fabric.

8. The knitted fabric according to claim 1, wherein Multifilament UHMWPE fibers are colored using supercritical CO2.

9. Tights, stockings or pantyhose comprising the knitted fabric according to any one of claims 1 to 8.

10. Tights, stockings or pantyhose according to claim 9, wherein: High wear areas are treated with wear pads.

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