Micro-porous polyethylene filament

Abstract

To provide a good dental floss and others.SOLUTION: A polyethylene (PE) and porous filament, and a method to manufacture such a filament are disclosed for a variety of uses including a dental floss, medical suture, and clothing or other woven fabric. Desired properties including porosity can be obtained by drawing, folding, and / or differently operating the PE filament. The PE filament is light in weight, easily held, easily slidable, non-shredded, and can be comfortable.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority of Provisional Application No. 63 / 112,956, filed on Nov. 12, 2021, which is incorporated herein by reference in its entirety for all purposes.

[0002] Broadly speaking, the present invention relates to polyethylene (PE) polymers, such as ultra - high molecular weight polyethylene (UHMWPE) polymers, and more specifically, to PE filaments for various applications including dental floss, medical sutures, and fabrics or clothing, and to methods of manufacturing PE filaments.

Background Art

[0003] Synthetic fibers, such as those used for dental floss, medical sutures, and fabric threads, should have various desirable material properties. For example, dental floss should be abrasion - resistant so that it does not fray, break, or otherwise rupture when passed between a user's teeth during use. Medical sutures, for example, should be biocompatible and exhibit strength and knot - holding properties suitable for specific applications. Fabric threads, for example, should have sufficient durability and strength for specific applications. What is needed in the art are polyethylene polymer fibers suitable for specific applications.

Summary of the Invention

Means for Solving the Problems

[0004] Porous PE filaments, and methods of manufacturing such filaments, are disclosed for various applications including dental floss or fabrics or clothing. Desired properties can be obtained by stretching, bending, and / or otherwise manipulating the PE filaments. The PE filaments can be easy to grip, easy to slide, non - fraying, and comfortable.

[0005] According to one embodiment (Embodiment 1), a microporous monofilament is provided, which comprises a continuous polyethylene filament having a width of 0.2 mm to 8.0 mm, a thickness of 0.02 mm to 0.35 mm, and a porosity of 15% to 90%.

[0006] According to yet another embodiment (Embodiment 2), a fabric is provided, which comprises at least one microporous monofilament, and the at least one microporous monofilament comprises a continuous polyethylene filament having a width of 0.2 mm to 8.0 mm, a thickness of 0.02 mm to 0.35 mm, and a porosity of 15% to 90%.

[0007] According to yet another embodiment (Embodiment 3), a method for manufacturing a microporous monofilament is provided, which includes preparing a polyethylene tape or membrane, increasing the porosity of the tape or membrane to 15% to 90% by stretching the polyethylene tape or membrane in at least one direction, and cutting the tape or membrane into monofilaments, and the method lacks any compression step for reducing the porosity.

[0008] The foregoing embodiments are merely examples and should not be read as limiting or narrowing the scope of any of the inventive concepts provided in other forms by the present disclosure. Although numerous examples are disclosed, still other embodiments will be apparent to those skilled in the art from the following detailed description. The following detailed description shows and describes specific examples. Therefore, the drawings and the detailed description should be regarded as illustrative rather than restrictive in nature.

Brief Description of the Drawings

[0009] The accompanying drawings are included for a further understanding of the present disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments, and together with the description, serve to explain the principles of the present disclosure.

[0010]

Figure 1

[0011]

Figure 2

[0012]

Figure 3

Mode for Carrying Out the Invention

[0013] Detailed Description Definitions and Terms The present disclosure is not intended to be read restrictively. For example, the terms used in this application should be read broadly in light of the meaning that one of ordinary skill in the art would ascribe to such terms.

[0014] Regarding terms representing inaccuracy, by using "about" and "approximately" interchangeably, it means a measurement value that includes the stated measurement value and also any measurement value reasonably close to the stated measurement value. A measurement value reasonably close to the stated measurement value deviates from the stated measurement value by a reasonably small amount that can be understood and easily determined by a person skilled in the art. Such deviations can be attributed to, for example, measurement errors, differences in measurement and / or manufacturing equipment calibration, human errors in reading and / or setting measurement values, performance and / or structural parameters considering differences in measurement values related to other components, specifically fine-tuning performed to optimize a specific implementation scenario, inaccurate adjustment and / or operation of an object by a person or a machine, and / or the like.

[0015] Description of various embodiments As will be apparent to those skilled in the art, the various aspects of the present disclosure can be implemented by any number of methods and apparatuses configured to perform the intended functions. It should be noted that the accompanying drawings referred to in this specification are not necessarily to scale and may be exaggerated to illustrate the various aspects of the present disclosure. In that regard, the drawings should not be construed as limiting.

[0016] Referring to FIG. 1, an exemplary method 100 for manufacturing a PE filament, such as a UHMWPE filament suitable for use as dental floss, is provided. Using the PE filament for other applications, such as other applications in clothing or other textiles, is also within the scope of the present disclosure. Method 100 may lack any compression step. The compression step would reduce and / or destroy the micropores in the filament.

[0017] In the preparation step 102 of method 100, a PE tape or membrane is prepared. The PE polymer of the tape or membrane may vary in its branches, crystal structure, molecular weight, and / or comonomer content. Suitable PE polymers include, for example, UHMWPE with a molecular mass exceeding 500,000 amu, high molecular weight polyethylene (HMWPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), and mixtures thereof. The PE polymer of the tape or membrane may be a homopolymer of ethylene or a copolymer of ethylene and at least one comonomer. In certain embodiments, the at least one comonomer may be an alkyl branched comonomer and / or an alpha-olefin or cyclic olefin having 3 to 20 carbon atoms. An example of a suitable comonomer includes, but is not limited to, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, cyclohexene, and dienes having up to 20 carbon atoms (such as butadiene or 1,4-hexadiene). The comonomer may be present in the copolymer in an amount of 0.001 mol% to 10 mol%, or 0.01 mol% to 5 mol%, or 0.1 mol% to 1 mol%. The PE tape or membrane may be a porous material, more specifically, a microporous material containing interconnected pores. In certain embodiments, the PE tape may be formed by pasting the PE polymer. The pasting process involves mixing PE particles with a lubricant, calendaring the lubricated particles into a tape while maintaining a temperature below the melting temperature of the PE polymer and the boiling point of the lubricant, and then drying the tape to remove the lubricant. In other embodiments, the PE tape may be formed by gelling the PE polymer or by another suitable processing technique. The PE membrane may be formed by stretching the PE tape.

[0018] One or more optional processing steps 103 can be performed on the PE tape or membrane obtained from the preparation step 102. As shown in FIG. 1, the optional processing steps 103 include a first stretching step 104, a cutting step 106, a second stretching step 108, a bending step 110, and a twisting step 112. Each of these steps will be further described later.

[0019] In the first stretching step 104 of the method 100, the PE tape or membrane is optionally stretched and / or extended in one or more directions (e.g., the machine direction (MD) and / or the transverse direction (TD)) so as to minimize any loss of porosity and, in many cases, at least maintain the porosity level of the tape or membrane without increasing it. One technique to assist with this is to stretch in one direction while holding the other direction stationary. The first stretching step 104 may involve passing the PE filaments through a series of rotating heating rollers or heating plates at a temperature below the melting temperature of the PE polymer, e.g., a temperature of 120°C to 140°C, more specifically 125°C to 130°C. The first stretching step 104 may be carried out at a stretching rate of 0.1% / sec to 100% / sec, more specifically 0.3% / sec to 10% / sec, more specifically 0.5% / sec to 3.5% / sec. In each direction, the PE tape or membrane may be stretched 1.01 times to 10 times, more specifically 1.05 times to 2.5 times, more specifically 1.05 times to 1.5 times. The ePE tape or membrane resulting from the first stretching step 104 may have a higher porosity than the microporous PE tape or membrane obtained from the preparation step 102 and may have nodes interconnected by fibrils.

[0020] In the cutting step 106 of the method 100, the PE tape or membrane can be optionally made into ribbon-shaped filaments having a desired width by slitting it longitudinally and elongating it, for example, by passing the tape through a series of gapped blades spaced at the desired width. The desired width after the cutting step 106 may be from 0.1 mm to 30 mm, more specifically from 0.1 mm to 10 mm, more specifically from 0.2 mm to 8.0 mm, more specifically from 0.25 mm to 7.5 mm, more specifically from 0.3 mm to 6.0 mm, more specifically from 0.3 mm to 3.5 mm, more specifically from 0.5 mm to 3.0 mm, and more specifically from 0.8 mm to 2.5 mm. In certain embodiments, the PE filament may remain as a single strand or monofilament. However, manufacturing multifilaments by fusing the PE filaments with other strands, braiding them, or otherwise bundling them in other forms is also within the scope of the present disclosure.

[0021] In the second stretching step 108 of method 100, by optionally stretching and / or elongating the PE filament in the machine direction (MD), an oriented PE (ePE) filament can be produced while taking care to maintain the desired porosity level. The second stretching step 108 may involve passing the PE filament through a series of rotating heating rollers or heating plates at a temperature below the melting temperature of the PE polymer, for example, a temperature of 120°C to 140°C, more specifically 125°C to 130°C. The second stretching step 108 may be carried out at a stretching rate of 0.1% / sec to 100% / sec, more specifically 0.3% / sec to 10% / sec, and more specifically 0.5% / sec to 3.5% / sec. The PE filament may be stretched 1.01 times to 10 times, more specifically 1.05 times to 2.5 times, and more specifically 1.05 times to 1.5 times. The ePE filament resulting from the second stretching step 108 may have a higher or lower porosity than the PE tape or membrane obtained from the preparation step 102 or the previous first stretching step 104, and may have nodes interconnected by fibrils. In certain embodiments of method 100, both the first stretching step 104 and the second stretching step 108 may be carried out. In other embodiments of method 100, only one of the first stretching step 104 or the second stretching step 108 may be carried out.

[0022] In the bending step 110 of method 100, by optionally bending the PE or ePE filament in the longitudinal direction, a narrower and thicker filament can be obtained. The width of the bent PE or ePE filament after the bending step 110 may be 0.2 mm to 8.0 mm, more specifically 0.25 mm to 7.5 mm, more specifically 0.3 mm to 6.0 mm, more specifically 0.3 mm to 3.5 mm, more specifically 0.5 mm to 3.0 mm, more specifically 0.8 mm to 2.5 mm, and more specifically 1.0 mm to 2.5 mm. The thickness of the PE or ePE filament after the bending step 110 may be 0.02 mm to 0.35 mm, more specifically 0.02 mm to 0.25 mm, more specifically 0.03 mm to 0.15 mm, and more specifically 0.04 mm to 0.10 mm.

[0023] In the twisting step 112 of the method 100, the PE or ePE filament may be optionally twisted. The PE or ePE filament may be twisted by a desired number of turns, for example, from 10 turns per meter to 1000 turns per meter, more specifically from 250 turns per meter to 750 turns per meter. This twisting step 112 can densify the filament. Modifying this twisting step 112, for example, other physical operations such as pressing the filament are also included in the scope of the present disclosure. The twisting step 112 can be carried out, for example, based on the specification of U.S. Patent No. 5,989,709.

[0024] In a further processing step 114 of the method 100, the PE or ePE filament may be processed for its intended use. In certain embodiments, the PE or ePE filament can be subjected to sterilization, scenting, embossing, winding onto a spool, and / or packaging for use as dental floss during the further processing step 114. Surprisingly, the PE or ePE dental floss is easy to grip, easy to slide, non-fraying (especially when provided as a monofilament rather than a multifilament), and can be comfortable even without wax.

[0025] In other embodiments, the PE or ePE filament may be incorporated into clothing or other textiles during the further processing step 114. The fabric includes both woven and knitted fabrics. The fabric may include one or more monofilament yarns, multifilament yarns, or combinations thereof. Such yarns may be formed from the above-mentioned PE or ePE filaments, as well as other materials such as wool, cotton, silk, linen, hemp, animal hair derived from various animals, angora, sisal, ramie, acrylic, polyester, polyamide, polyaramid, polyurethane, acetate, rayon, polybenzimidazole, polybenzoxazole, lyocell, modacrylic, polyvinylidene chloride, carbon, glass, cellulose, cellulose acetate, cellulose ester, elastane, or combinations thereof.

[0026] A PE or ePE filament can be lighter than current ePTFE dental floss. This is because PE is more than 50% lighter than PTFE. In certain embodiments, the weight per length (i.e., linear density) of the PE or ePE filament can be less than 1040 dTex, more specifically 90 dTex to 1040 dTex, more specifically 100 dTex to 1000 dTex, more specifically 200 dTex to 700 dTex, more specifically 250 dTex to 650 dTex, more specifically 300 dTex to 600 dTex, and more specifically 350 dTex to 550 dTex. In comparison, the weight per length of current ePTFE dental floss with a similar porosity exceeds 1040 dTex.

[0027] Other properties of the PE or ePE filament may be suitable for use as dental floss. The bulk density of the PE or ePE filament can be 0.1 g / cc to 0.8 g / cc, more specifically 0.2 g / cc to 0.7 g / cc, more specifically 0.14 g / cc to 0.76 g / cc. The porosity of the PE or ePE filament can be 15% to 90%, more specifically 20% to 80%, more specifically 19% to 76%, and more specifically 30% to 60%. The breaking strength of the PE or ePE filament can be 3 N to 50 N, more specifically 5 N to 30 N, and more specifically 10 N to 25 N. The tenacity of the PE or ePE filament can be 0.5 cN / dTex to 20 cN / dTex, more specifically 0.7 cN / dTex to 18 cN / dTex, more specifically 1.0 cN / dTex to 10 cN / dTex, more specifically 1.5 cN / dTex to 8 cN / dTex. The tensile strength of the PE or ePE filament can be 0.1 GPa to 1.5 GPa, more specifically 0.2 GPa to 0.8 GPa, more specifically 0.3 GPa to 0.6 GPa. The maximum load point elongation of the PE or ePE filament can be 1% to 100%, more specifically 5% to 95%, more specifically 10% to 75%.

[0028] In dental floss applications, despite the filament having a lower tensile strength than fully dense filaments, the microporous structure of the filament is thought to adapt to compression of the filament (e.g., when passing through the narrow space between teeth), and this compression is thought to increase resistance to shredding or breaking. Further, the microporous structure of the filament enables the filament to have a lower stiffness and provides additional comfort to the gums and allows the filament to be gripped more comfortably. In fabric applications, the filaments can produce lightweight materials having desired properties such as low air permeability, low wet pick up, and a favorable hand.

[0029] Test Methods Needless to say, while certain methods and equipment are described hereinafter, other methods or equipment determined to be suitable by those skilled in the art may alternatively be utilized.

[0030] Weight per unit length of filament (dTex) A 9-meter length of filament was obtained by winding 10 times the length of the filament (5 round trips) around two pins separated by 0.9 meters. The 9-meter length was then weighed on a scale to an accuracy of 0.0001 grams. The weight was then multiplied by 1000 to obtain the weight per unit length in denier (g / 9000m). This denier measurement was then multiplied by 1.1111 to obtain the weight per unit length in dTex.

[0031] Filament width (mm) The filament width was measured in a conventional manner using a 10X eye loop having a graduation in 0.1 mm increments. The width was determined to the nearest 0.05 mm by obtaining three measurements and averaging them.

[0032] Filament thickness (mm) The filament thickness (or height) was measured using a caliper gauge with an accuracy of 0.001 mm. Care was taken not to compress the filament with the caliper gauge. Three measurements were taken and averaged in 0.001 mm increments.

[0033] Filament density (g / cc) Using the weight per length of filament, filament width, and filament thickness measured previously, the filament density was calculated using the following formula.

Number

[0034] Porosity of filament (%) The porosity of the filament is the amount of air volume compared to the total volume of the sample (air + polymer). It was assumed that fully dense polyethylene or UHMWPE is 0.94 g / cc. It was assumed that fully dense polytetrafluoroethylene or PTFE is 2.18 g / cc. The porosity of the filament (%) was calculated using the following formula.

Number

[0035] Breaking strength (N) and elongation (%) of filament The filament breaking strength was the measured value of the maximum load required to break (rupture) the filament. The breaking strength was measured using a tensile testing machine, for example, an Instron Machine in Canton, Massachusetts. The Instron machine was equipped with a fiber (horn type) jaw. The jaw was suitable for fixing the fiber and strand article during the measurement of the tensile load. The crosshead speed of the tensile testing machine was 25.4 cm per minute. The gauge length was 25.4 cm. Five measurements for each fiber type were taken and the average value was reported in Newton units. The elongation of the filament before rupture at the maximum load point was also measured. Five elongation measurements for each fiber type were taken and the average value was reported in percent units.

[0036] Tenacity of filament (cN / dTex) The tenacity of the filament is the breaking strength of the filament normalized with respect to the weight per fiber length. The tenacity of the filament (cN / dTex) was calculated using the following formula.

Equation

[0037] Tensile strength of filament (GPa) The tensile strength of the filament is the tensile strength of the filament normalized with respect to the cross-sectional area. Assuming that the polyethylene or UHMWPE of full density is 0.94 g / cc, and that a tenacity of 1 cN / dTex would be equal to 13,633 psi. The filament tensile strength (GPa) was calculated using the following formula.

Equation

[0038] SEM sample preparation method Cross-sectional SEM samples were prepared by spraying liquid nitrogen on each filament sample and then cutting the sprayed sample with a diamond knife in a Leica Ultracut UCT available from Leica Microsystems, Wetzlar, Germany.

[0039] Matrix tensile strength (MTS) To identify the MTS, the sample membranes were cut longitudinally and transversely using ASTM D412 - Dogbone Die - Type F (DD412F). The tensile break load was measured using an INSTRON® 5500R (Illinois Tool Works Inc., Norwood, Massachusetts) tensile testing machine equipped with grips having a flat surface and a "200 lb" (approximately 90.72 kg) load cell. The gauge length for the grips was set at 8.26 cm and the strain rate was set at 0.847 cm / s. After placing the sample in the grips, a baseline was obtained by pulling the sample in by 1.27 cm, followed by conducting a tensile test at the aforementioned speed. Two samples were individually tested for each condition, and the average of the measured maximum load (i.e., peak force) values was used for MTS calculation. The longitudinal and transverse MTS were calculated using the following equations. [Number]

[0040] Example Inventive Example A Mass 8.8 grams / m 2 A PE membrane containing UHMWPE was obtained, having a porosity of 76%, a longitudinal matrix tensile strength of 24,600 psi, and a transverse matrix tensile strength of 13,200 psi.

[0041] The membrane was then slit lengthwise to form a cross - section of filaments 3.0 mm wide × 0.048 mm thick having a weight per length of 336 dtex and a density of 0.23 g / cc, resulting in a porosity of 76% (assuming a fully dense PE of 0.94 g / cc). This filament was subsequently bent through a 2.0 mm wide eyelet. The bent filament had the following properties: width 1.8 mm, height (or thickness) 0.089 mm, weight per length 336 dtex, bulk density 0.21 g / cc, porosity 78%, breaking strength 6.67 N, tenacity 1.99 cN / dtex, tensile strength 0.19 GPa, and maximum load point elongation 3.0%.

[0042] This folded filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Further, the porosity in the filament enabled the filament to have a low rigidity, provided additional comfort to the gums, and enabled the filament to be gripped more comfortably.

[0043] Example B of the Invention A 5.3 mm wide filament was slit longitudinally from the membrane of Example A. The filament of the longitudinally slit membrane was then stretched across a heating plate set at 140 °C at a stretching rate of 3.5% / sec with a draw ratio of 1.15:1. Following this first stretch, a second stretch was applied across a heating plate set at 140 °C at a stretching rate of 2.6% / sec with a draw ratio of 1.10:1. Following this second stretch, a third stretch was applied across a heating plate set at 140 °C at a stretching rate of 2.9% / sec with a draw ratio of 1.10:1. Following this third stretch, a fourth stretch was applied across a heating plate set at 140 °C at a stretching rate of 1.8% / sec with a draw ratio of 1.08:1. The stretched filament was then bent through an eyelet 2.0 mm wide. The bent filament had the following characteristics, namely a width of 1.5 mm, a height (or thickness) of 0.043 mm, a weight per length of 371 dtex, a bulk density of 0.58 g / cc, a porosity of 38%, a breaking strength of 20.11 N, a tenacity of 5.42 cN / dtex, a tensile strength of 0.51 GPa, and a maximum load point elongation of 2.6%.

[0044] This filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Further, the porosity in the filament enabled the filament to have a low rigidity, provided additional comfort to the gums, and enabled the filament to be gripped more comfortably.

[0045] Example C of the Invention A PE membrane containing UHMWPE with a width of 107 millimeters, a thickness of 20 microns, a surface density of 8.5 grams per square meter, and a porosity of 57.8% was obtained. Then, this membrane was slit longitudinally to form a cross-section with a width of 6.9 mm. Subsequently, the longitudinally slit membrane was stretched over a heating plate set at 120 °C at a stretching rate of 3.1% / sec with a stretching ratio of 1.10:1. Following this first stretch, a second stretch was performed over a heating plate set at 120 °C at a stretching rate of 1.4% / sec with a stretching ratio of 1.10:1. Following this second stretch, a third stretch was performed over a heating plate set at 120 °C at a stretching rate of 0.7% / sec with a stretching ratio of 1.05:1. Following this third stretch, a fourth stretch was performed over a heating plate set at 120 °C at a stretching rate of 0.8% / sec with a stretching ratio of 1.05:1. Following this fourth stretch, a fifth stretch was performed over a heating plate set at 120 °C at a stretching rate of 0.6% / sec with a stretching ratio of 1.05:1. The filament had the following properties: a width of 3.1 mm, a height of 0.023 mm, a weight per unit length of 410 dtex, a bulk density of 0.58 g / cc, a porosity of 38%, a breaking strength of 24.95 N, a tenacity of 6.09 cN / dtex, a tensile strength of 0.57 GPa, and a maximum load point elongation of 11.4%.

[0046] This filament was easy to grip and slid easily between the teeth without any tendency to shred or break during flossing. Furthermore, the porosity in the filament enabled the filament to be less rigid, provided additional comfort to the gum line, and made the filament more comfortable to grip.

[0047] Example D of the Invention A PE filament containing UHMWPE was produced in the same manner as Example C, except that the stretched filament was subsequently bent by passing it through an eyelet with a width of 2.0 mm. The bent filament had the following properties: width 1.6 mm, height 0.049 mm, weight per length 409 dtex, bulk density 0.52 g / cc, porosity 45%, breaking strength 24.78 N, tenacity 6.06 cN / dtex, tensile strength 0.57 GPa, and maximum load point elongation 11.9%.

[0048] This filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Furthermore, the porosity in the filament made it possible to lower the rigidity of the filament, provided additional comfort to the gumline, and made it possible to grip the filament more comfortably. This filament demonstrated an improved floss from the perspective of ease of use due to the changes in thickness and width resulting from subsequent bending through a 2.0 mm wide eyelet, and from the sense of being more overall effective, surpassing Example C.

[0049] Example E of the Invention A PE filament containing UHMWPE was produced in the same manner as Example D, except that the bent filament was subsequently twisted at 630 turns per meter by passing it through a ring twister. The twisted filament had the following properties: diameter 0.31 mm, weight per length 477 dtex, bulk density 0.63 g / cc, porosity 33%, breaking strength 15.44 N, tenacity 3.24 cN / dtex, tensile strength 0.30 GPa, and maximum load point elongation 14.8%.

[0050] This twisted filament is easy to grip and slides easily between teeth without any tendency to fray or break during flossing. Furthermore, the porosity in the filament enables the stiffness of the twisted filament to be lowered, provides additional comfort to the gums, and also allows the filament to be gripped more comfortably. This twisted filament can be said to be preferable in applications where a filament with a more rounded shape than a square or ribbon shape is desired.

[0051] Example F of the Invention A PE membrane containing UHMWPE with a width of 500 millimeters, a thickness of 30 microns, a surface density of 18.1 grams per square meter, and a porosity of 36% was obtained. Subsequently, the membrane was stretched in the machine direction through a hot air dryer set at 120 °C with a draw ratio of 2:1 and a draw speed of 4.3% / sec. Following this machine direction stretch, a transverse stretch was applied in a furnace at 130 °C with a draw ratio of 4.7:1 and a draw speed of 15.6% / sec. The resulting membrane had the following properties: a width of 697 millimeters, a thickness of 14 microns, a porosity of 66%, and, when tested according to ASTM D412, maximum loads of 7.65 Newtons × 6.23 Newtons and maximum load point elongations of 25.6% × 34.3% in the machine direction and transverse direction, respectively. The membrane had a Gurley time of 15.7 seconds. The Gurley time is defined as the number of seconds required for 100 cubic centimeters (1 deciliter) of air to pass through a given material of 1.0 square inch under a pressure difference of 4.88 inches of water (0.176 psi) (ISO 5636-5:2003).

[0052] Filaments 5.1 mm in length were slit lengthwise from this membrane. These lengthwise slit filaments were subsequently bent through an eyelet 1.0 mm wide. The bent filaments had the following properties: a width of 1.3 mm, a height of 0.075 mm, a weight per unit length of 228 dtex, a bulk density of 0.23 g / cc, a porosity of 75%, a breaking strength of 6.23 N, a tenacity of 2.74 cN / dtex, a tensile strength of 0.26 GPa, and a maximum load point elongation of 19.4%.

[0053] This filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Further, the porosity in the filament enabled the filament to have a low rigidity, provided additional comfort to the gingiva, and also enabled the filament to be gripped more comfortably.

[0054] Inventive Example G A 7.6 mm filament was slit longitudinally from the membrane of Example F. This longitudinally slit filament was subsequently bent through an eyelet having a width of 1.0 mm. The bent filament had the following characteristics, namely a width of 1.4 mm, a height of 0.095 mm, a weight per length of 340 dtex, a bulk density of 0.26 g / cc, a porosity of 72%, a breaking strength of 9.21 N, a tenacity of 2.71 cN / dtex, a tensile strength of 0.25 GPa, and a maximum load point elongation of 18.2%.

[0055] This filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Further, the porosity in the filament enabled the filament to have a low rigidity, provided additional comfort to the gingiva, and also enabled the filament to be gripped more comfortably.

[0056] Inventive Example H An 8.9 mm filament was slit longitudinally from the membrane of Example F. This longitudinally slit filament was subsequently bent through an eyelet having a width of 2.0 mm. The bent filament had the following characteristics, namely a width of 1.7 mm, a height of 0.110 mm, a weight per length of 420 dtex, a bulk density of 0.22 g / cc, a porosity of 77%, a breaking strength of 13.2 N, a tenacity of 3.15 cN / dtex, a tensile strength of 0.30 GPa, and a maximum load point elongation of 26.0%.

[0057] Figure 2 is a scanning electron microscope (SEM) image showing this filament at a magnification of 5000:1. The microporosity of the filament can be clearly seen in the SEM image.

[0058] This filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Furthermore, the porosity in the filament enabled the filament to have a lower rigidity, provided additional comfort to the gums, and made it possible to grip the filament more comfortably.

[0059] Comparative Example Z SEM images of a microporous ePTFE filament used to form a commercial dental floss were taken. The filament had the following characteristics: width 2.1 mm, height 0.103 mm, weight per unit length 1030 dtex, bulk density 0.48 g / cc, porosity 78%, breaking strength 19.13 N, tenacity 1.86 cN / dtex.

[0060] Figure 3 is a scanning electron microscope (SEM) image showing this filament at a magnification of 5000:1. The microporosity of the filament can be clearly seen in the SEM image.

[0061] This filament was easy to grip and slid easily between the teeth without any tendency to fray or break during flossing. Furthermore, the porosity in the filament enabled the filament to have a lower rigidity, provided additional comfort to the gums, and made it possible to grip the filament more comfortably.

[0062] Example I of the Invention A PE membrane with a width of 1000 millimeters, a thickness of 16.5 microns, a surface density of 5.5 grams per square meter, and a porosity of 64.5% was obtained. A 2.0 - mm filament was slit longitudinally from the membrane. This longitudinally slit filament was then bent through an eyelet with a width of 1.0 mm. The bent filament had the following properties: a width of 0.8 mm, a height of 0.060 mm, a weight per unit length of 103 dtex, a bulk density of 0.22 g / cc, a porosity of 77%, a breaking strength of 4.49 N, a tenacity of 4.37 cN / dtex, a tensile strength of 0.41 GPa, and a maximum load - point elongation of 71.5%.

[0063] Example J of the invention A 3.8 - mm filament was slit longitudinally from the membrane of Example I. This longitudinally slit filament was then bent through an eyelet with a width of 1.0 mm. The bent filament had the following properties: a width of 0.9 mm, a height of 0.077 mm, a weight per unit length of 186 dtex, a bulk density of 0.27 g / cc, a porosity of 71%, a breaking strength of 8.41 N, a tenacity of 4.55 cN / dtex, a tensile strength of 0.43 GPa, and a maximum load - point elongation of 72.3%.

[0064] Example K of the invention A 5.8 - mm filament was slit longitudinally from the membrane of Example I. This longitudinally slit filament was then bent through an eyelet with a width of 1.0 mm. The bent filament had the following properties: a width of 1.0 mm, a height of 0.115 mm, a weight per unit length of 284 dtex, a bulk density of 0.25 g / cc, a porosity of 73%, a breaking strength of 12.54 N, a tenacity of 4.40 cN / dtex, a tensile strength of 0.41 GPa, and a maximum load - point elongation of 74.9%.

[0065] This filament was easy to grip and slid easily between the teeth without any tendency to shred or break during flossing. Further, the porosity in the filament enabled the filament to have a low rigidity, provided additional comfort to the gums, and enabled the filament to be gripped more comfortably. The filament can be easily disposable.

[0066] Comparative fabric example Y A 4-ply nylon multifilament yarn with a total weight per length of 367 dTex was obtained. By weaving this yarn in a 1×2 twill pattern, a woven fabric with a width of 254 cm consisting of 48 picks per inch (ppi) × 48 ends per inch (epi) was manufactured. This is converted to 18.9 picks per cm × 18.9 ends per cm. The following measured values were obtained on this fabric, namely, weight per area of 168 g / m 2 , thickness of 0.54 mm, air permeability of 67 cubic feet per minute (cfm), wet pickup of 27%, and wet pickup of 45 grams per square meter (gsm). The hand was measured to be 248 g.

[0067] Inventive fabric example L The 103 dTex inventive filament of Example I was woven in the same 1×2 twill pattern as Comparative Example Y, except that all other weft yarns in the woven fabric were replaced. The following measured values were obtained on this fabric, namely, weight per area of 140 g / m 2 , thickness of 0.54 mm, air permeability of 69 cubic feet per minute (cfm), wet pickup of 24%, and wet pickup of 34 grams per square meter (gsm). The hand was measured to be 238 g.

[0068] Inventive fabric example M The filament of the present invention of 186 dTex of Example J was woven in the same 1×2 twill weave pattern as Comparative Example Y using a 4-ply nylon multifilament yarn with a total weight per length of 367 dTex, except that it replaced all other weft yarns in the woven fabric. The following measured values were obtained for this fabric, namely, weight per area of 151 g / m 2 , thickness of 0.54 mm, air permeability of 43 cubic feet per minute (cfm), and wet pickup of 24%, resulting in a wet pickup of 36 grams per square meter (gsm). The handfeel was measured to be 359 g.

[0069] Fabric of the Invention, Example N The filament of the present invention of 284 dTex of Example K was woven in the same 1×2 twill weave pattern as Comparative Example Y using a 4-ply nylon multifilament yarn with a total weight per length of 367 dTex, except that it replaced all other weft yarns in the woven fabric. The following measured values were obtained for this fabric, namely, weight per area of 165 g / m 2 , thickness of 0.56 mm, air permeability of 29 cubic feet per minute (cfm), and wet pickup of 23%, resulting in a wet pickup (WPU) of 38 grams per square meter (gsm). The handfeel was measured to be 530 g.

[0070] The fabric properties of the previous examples are summarized in Table 1 below.

Table 1

[0071] Consumers desire to wear clothing made from the lightest possible fabric that can minimize air permeability. It is also desirable for these lightweight fabrics to have low wet pick-up properties. Further, when these fabrics are extremely lightweight, it may be desirable to enhance the texture or stiffness of the fabric to give the wearer the sense that the fabric or clothing provides sufficient overall protection. Nylon yarn is considered to offer excellent characteristics for these properties in the apparel industry. Nevertheless, improvement of these properties in the apparel industry is desired.

[0072] In any of the cases shown in Table 1 above, the fabric of the present invention in Invention Examples L to N is lighter than the 100% nylon control fabric of Comparative Example Y. In the case where the weight of the fabric of the present invention is closest to the control fabric, the air permeability is significantly reduced. Even in cases where the gap in fabric weight is larger, there is still a substantial decrease in air permeability. Even in the case with the largest difference in fabric weight, the measured air permeability values are similar. Thus, in all cases, it is shown that an extremely low air permeability can be provided for a given lightweight fabric.

[0073] Similarly, in any of the cases, these fabrics with low air permeability per unit weight also show lower wet pick-up properties. The lower the fabric weight, the lower the wet pick-up. Also, in all cases, the fabric of the present invention shows a lower wet pick-up in percentage per unit weight than the control fabric.

[0074] As can also be seen from Table 1, in the case where the fabric weight is closest to the control fabric, the texture is significantly enhanced. Even in cases where the gap in fabric weight is larger, the texture is still substantially enhanced. Even in the case with the largest difference in fabric weight, the texture only slightly decreases. Thus, in all cases, it is shown that a higher texture can be provided for a given fabric weight as compared to the control.

[0075] The invention of the present application has been described above generally and in relation to specific embodiments. As will be apparent to those skilled in the art, various modifications and changes can be made to the embodiments without departing from the scope of the disclosure. Accordingly, the embodiments are intended to cover such modifications and variations if they fall within the scope of the appended claims and their equivalents. (Aspect) (Aspect 1) A microporous monofilament, having a width of 0.2 mm to 8.0 mm, a thickness of 0.02 mm to 0.35 mm, and a porosity of 15% to 90%. A microporous monofilament comprising a continuous polyethylene filament. (Aspect 2) The microporous monofilament according to Aspect 1, wherein the continuous polyethylene filament is dental floss. (Aspect 3) The microporous monofilament according to Aspect 1 or 2, wherein the continuous polyethylene filament contains ultra-high molecular weight polyethylene (UHMWPE). (Aspect 4) The microporous monofilament according to Aspect 3, wherein the continuous polyethylene filament contains drawn UHMWPE. (Aspect 5) wherein the width is 0.3 mm to 6.0 mm, and the thickness is 0.022 mm to 0.325 mm, The microporous monofilament according to any one of Aspects 1 to 4. (Aspect 6) wherein the width is 0.5 mm to 3.0 mm, and the thickness is 0.03 mm to 0.15 mm, The microporous monofilament according to Aspect 5. (Aspect 7) wherein the width is 0.8 mm to 2.5 mm, and the thickness is 0.04 mm to 0.10 mm, The microporous monofilament according to Aspect 6. (Aspect 8) The microporous monofilament according to any one of Aspects 1 to 7, wherein the porosity is 30% to 80%. (Aspect 9) The microporous monofilament according to any one of Aspects 1 to 8, wherein the tensile strength of the continuous polyethylene filament is 0.1 GPa to 1.5 GPa. (Aspect 10) The microporous monofilament according to any one of Aspects 1 to 9, wherein the breaking strength of the continuous polyethylene filament is 3 N to 50 N. (Aspect 11) The microporous monofilament according to any one of Aspects 1 to 10, wherein the tenacity of the continuous polyethylene filament is 0.5 cN / dTex to 20 cN / dTex. (Aspect 12) The microporous monofilament according to any one of Aspects 1 to 11, wherein the maximum load point elongation of the continuous polyethylene filament is 1% to 100%. (Aspect 13) The microporous monofilament according to any one of Aspects 1 to 12, wherein the linear density of the continuous polyethylene filament is 90 dTex to 1040 dTex. (Aspect 14) The microporous monofilament according to Aspect 13, wherein the linear density is 200 dTex to 700 dTex. (Aspect 15) The microporous monofilament according to Aspect 14, wherein the linear density is 250 dTex to 650 dTex. (Aspect 16) The microporous monofilament according to Aspect 15, wherein the linear density is 300 dTex to 600 dTex. (Aspect 17) A multifilament containing a plurality of microporous monofilaments according to any one of Aspects 1 to 16. (Aspect 18) A fabric containing at least one microporous monofilament, wherein the at least one microporous monofilament is with a width of 0.2 mm to 8.0 mm, a thickness of 0.02 mm to 0.35 mm, and a porosity of 15% to 90% A fabric comprising continuous polyethylene filaments. (Aspect 19) The fabric according to aspect 18, wherein the fabric further comprises one or more yarns. (Aspect 20) The fabric according to aspect 19, wherein the one or more yarns are monofilament yarns, multifilament yarns, or a combination thereof. (Aspect 21) The fabric according to aspect 19 or 20, wherein the one or more yarns comprise the continuous polyethylene filaments, or another material selected from the group consisting of wool, cotton, silk, linen, hemp, animal hair derived from various animals, angora, sisal, ramie, acrylic, polyester, polyamide, polyaramide, polyurethane, acetate, rayon, polybenzimidazole, polybenzoxazole, lyocell, modacrylic, polyvinylidene chloride, carbon, glass, cellulose, cellulose acetate, cellulose ester, elastic fibers, or a combination thereof. (Aspect 22) The fabric according to any one of aspects 18 to 21, wherein the fabric is a woven fabric or a knitted fabric. (Aspect 23) The fabric according to any one of aspects 18 to 22, wherein the continuous polyethylene filaments comprise ultra-high molecular weight polyethylene (UHMWPE). (Aspect 24) The fabric according to aspect 23, wherein the continuous polyethylene filaments comprise drawn UHMWPE. (Aspect 25) The fabric according to any one of aspects 18 to 24, wherein the continuous polyethylene filaments have a tensile strength of 0.1 GPa to 1.5 GPa. (Aspect 26) The fabric according to any one of aspects 18 to 25, wherein the porosity is 30% to 80%. (Aspect 27) The fabric according to any one of Aspects 18 to 26, wherein the breaking strength of the micro-porous monofilament is 3 N to 50 N. (Aspect 28) The fabric according to any one of Aspects 18 to 27, wherein the tenacity of the continuous polyethylene filament is 0.5 cN / dTex to 20 cN / dTex. (Aspect 29) The fabric according to any one of Aspects 18 to 28, wherein the maximum load point elongation of the continuous polyethylene filament is 1% to 100%. (Aspect 30) The fabric according to any one of Aspects 18 to 29, wherein the linear density of the continuous polyethylene filament is 90 dTex to 1040 dTex. (Aspect 31) The fabric according to any one of Aspects 18 to 30, wherein a plurality of the micro-porous monofilaments form a yarn. (Aspect 32) A method for manufacturing a micro-porous monofilament, comprising: preparing a polyethylene tape or membrane, and cutting the tape or membrane into monofilaments. The method for manufacturing a micro-porous monofilament, wherein the porosity of the monofilament is 15% to 90%, and the method lacks any compression step for reducing the porosity. The method for manufacturing a micro-porous monofilament according to Aspect 32, further comprising stretching the polyethylene tape or membrane before the cutting step. (Aspect 33) The method according to Aspect 32 or 33, further comprising stretching the monofilament after the cutting step. (Aspect 34) The method according to any one of Aspects 32 to 34, further comprising bending the monofilament in the longitudinal direction. (Aspect 35) The method according to any one of Aspects 32 to 34, further comprising bending the monofilament in the longitudinal direction. (Aspect 36) The method according to any one of aspects 32 to 35, further comprising twisting the monofilament. (Aspect 37) The method according to any one of aspects 32 to 36, further comprising winding the monofilament onto a spool and packaging the spool for use as dental floss. (Aspect 38) The method according to any one of aspects 32 to 37, further comprising incorporating the monofilament into a fabric. (Aspect 39) The method according to any one of aspects 32 to 38, further comprising forming the polyethylene tape by paste treatment. (Aspect 40) The method according to any one of aspects 32 to 39, further comprising forming the polyethylene tape by gel treatment.

Claims

1. A microporous monofilament, The width is 0.2 mm to 8.0 mm, The thickness is between 0.02 mm and 0.35 mm, and Porosity is 19% to 76% comprising continuous polyethylene filaments; The microporous monofilament, wherein the continuous polyethylene filament is dental floss.

2. 2. The microporous monofilament of claim 1, wherein the continuous polyethylene filaments comprise ultra-high molecular weight polyethylene (UHMWPE).

3. 3. The microporous monofilament of claim 2, wherein the continuous polyethylene filaments comprise expanded UHMWPE.

4. the width is between 0.3 mm and 6.0 mm; and The thickness is 0.022 mm to 0.325 mm. The microporous monofilament according to any one of claims 1 to 3.

5. the width is between 0.5 mm and 3.0 mm; and The thickness is 0.03 mm to 0.15 mm. The microporous monofilament according to claim 4.

6. the width is between 0.8 mm and 2.5 mm; and The thickness is 0.04 mm to 0.10 mm. The microporous monofilament according to claim 5.

7. The microporous monofilament according to any one of claims 1 to 6, wherein the continuous polyethylene filament has a tensile strength of 0.1 GPa to 1.5 GPa.

8. The microporous monofilament according to any one of claims 1 to 7, wherein the breaking strength of the continuous polyethylene filament is from 3N to 50N.

9. The microporous monofilament according to any one of claims 1 to 8, wherein the tenacity of the continuous polyethylene filaments is from 0.5 cN / dTex to 20 cN / dTex.

10. The microporous monofilament according to any one of claims 1 to 9, wherein the continuous polyethylene filament has a maximum load point elongation of 1% to 100%.

11. The microporous monofilament according to any one of claims 1 to 10, wherein the continuous polyethylene filaments have a linear density of from 90 dTex to 1040 dTex.

12. The microporous monofilament according to claim 11, wherein said linear density is between 200 dTex and 700 dTex.

13. The microporous monofilament according to claim 12, wherein said linear density is between 250 dTex and 650 dTex.

14. The microporous monofilament according to claim 13, wherein said linear density is between 300 dTex and 600 dTex.

15. A multifilament comprising a plurality of microporous monofilaments according to any one of claims 1 to 14.

16. A fabric comprising at least one microporous monofilament, the at least one microporous monofilament comprising: The width is 0.2 mm to 8.0 mm, The thickness is between 0.02 mm and 0.35 mm, and Porosity is 19% to 76% A fabric comprising continuous polyethylene filaments.

17. 17. The fabric of claim 16, wherein the fabric further comprises one or more yarns.

18. 20. The fabric of claim 17, wherein the one or more yarns are monofilament yarns, multifilament yarns, or a combination thereof.

19. 19. The fabric of claim 17 or 18, wherein the one or more yarns comprise the continuous polyethylene filaments or another material selected from the group consisting of wool, cotton, silk, flax, hemp, hair from various animals, angora, sisal, ramie, acrylic, polyester, polyamide, polyaramid, polyurethane, acetate, rayon, polybenzimidazole, polybenzoxazole, lyocell, modacrylic, polyvinylidene chloride, carbon, glass, cellulose, cellulose acetate, cellulose esters, elastic fibers, or combinations thereof.

20. The fabric of any one of claims 16 to 19, wherein the fabric is a woven or knitted fabric.

21. 21. The fabric of any one of claims 16-20, wherein the continuous polyethylene filaments comprise ultra-high molecular weight polyethylene (UHMWPE).

22. 22. The fabric of claim 21, wherein the continuous polyethylene filaments comprise expanded UHMWPE.

23. The fabric of any one of claims 16 to 22, wherein the continuous polyethylene filaments have a tensile strength of 0.1 GPa to 1.5 GPa.

24. The fabric according to any one of claims 16 to 23, wherein the breaking strength of the microporous monofilament is 3N to 50N.

25. 25. The fabric of any one of claims 16 to 24, wherein the tenacity of the continuous polyethylene filaments is from 0.5 cN / dTex to 20 cN / dTex.

26. The fabric of any one of claims 16 to 25, wherein the continuous polyethylene filaments have an elongation at maximum load of 1% to 100%.

27. 27. The fabric of any one of claims 16 to 26, wherein the continuous polyethylene filaments have a linear density of from 90 dTex to 1040 dTex.

28. The fabric of any one of claims 16 to 27, wherein a plurality of the microporous monofilaments are in the form of a yarn.

29. 1. A method for producing a microporous monofilament, comprising: providing a polyethylene tape or membrane; and Cutting the tape or membrane into monofilaments Including, A method for producing a microporous monofilament, wherein the porosity of said monofilament is between 19% and 76%, and said method is devoid of any compression step to reduce said porosity.

30. 30. The method of claim 29, further comprising stretching the polyethylene tape or membrane prior to the cutting step.

31. 31. The method of claim 29 or 30, further comprising stretching the monofilament after the cutting step.

32. 32. The method of any one of claims 29 to 31, further comprising bending the monofilament lengthwise.

33. The method of any one of claims 29 to 32, further comprising twisting the monofilament.

34. The method of any one of claims 29 to 33, further comprising winding the monofilament onto a spool and packaging the spool for use as a dental floss.

35. The method of any one of claims 29 to 34, further comprising incorporating the monofilament into a textile fabric.

36. The method of any one of claims 29 to 35, further comprising forming the polyethylene tape by a pasting process.

37. The method of any one of claims 29 to 36, further comprising forming the polyethylene tape by a gel process.

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