Patent Application
20220213645
The present invention relates to treatment of cellulosic fibers.
Cellulosic fibers, sourced from plants, have long been used to produce both traditional textile woven and knit fabrics, as well as nonwoven textiles. In general, naturally occurring cellulosic fibers are of three basic types: seed fibers such as cotton and kapok, leaf fibers such as abaca and sisal, and bast fibers such as flax, hemp, jute and kenaf. The seed fibers are known for softness, and that in combination with the length of cotton fibers, made them highly desired for the manufacture of yarns and fabrics, particularly for clothing. Bast and leaf fibers, being generally more coarse and stiff have historically tended to be used more for cordage, netting, and matting.
Along with animal hair and fibers, and silk, which are chemically protein fibers, the naturally occurring cellulosics were the source of fibers for textile processing for many centuries. And through those centuries, textile and fiber development has been motivated by a desire to modify these materials to provide new or augmented properties or to improve processing efficiency. While much of this relied upon mechanical means to improve fiber processing or husbandry to improve fiber properties, chemistry was also used to improve fiber aesthetics, such as through dyeing, and softness, such as through scouring or retting to remove certain chemicals associated with the surface of natural fibers.
There remained both need for, and scientific interest in, fibers that had properties and economics that were beyond what had been achievable with natural fibers. The invention of rayon in 1846 marked the beginning of synthetic fiber development. Using nature as an inventive prompt, rayon, a regenerated cellulose, was developed to be a more cost effective alternative to silk fibers. In the 1900's, the development of synthetic fibers based on petrochemicals led to such industry-changing inventions as polyamide, polyester, polyaramid, and polyolefin fibers, to name some major examples. The list of synthetic fibers with properties that are specific to their polymer chemistry has supported the expansion of fiber-based materials in common use across the full spectrum of human industry. And with that have come concomitant improvements in textile type products that have been in use for centuries, as well as new products spawned by 20th and 21st Century technology demands.
While synthetic and natural fiber development has provided expansive design options for products produced utilizing those fibers, there remains a need for and interest in modifications to the surfaces of those fibers which advantageously alters the surface activity of those fibers without negatively impacting the physical performance of the fibers. For example, cellulosic fibers are not compatible with quaternary ammonium compounds that are used to provide a sanitizing functionality to products derived from those fibers. Further, cellulosic fibers are particularly flammable, and certain surface treatments are known to increase the flame resistance of these fibers. However, many of the historically-noted flame resistant treatment chemicals for fibers have known negative environmental and health impacts, and so chemistries that are both compatible with the fiber chemistry and user health have value in the industry.
Therefore, there remains a need in the art for means to impart multiple performance features to certain fibers with a chemical surface treatment that does not have a negative impact on the physical or aesthetic properties of the fibers so treated.
It is an aspect of certain embodiments of the present invention that natural or synthetic cellulosic fibers and products manufactured using those fibers in some portion, either as a single fiber component or as a blend with other synthetic or natural fibers, may be treated with cationic compound solutions which alter the surface activity of the treated cellulosic fibers. It is a further aspect of the invention that the treatment, in certain embodiments, is durable to rinsing with water and detergent washing.
It is a further aspect of certain embodiments of the instant invention that such modified surface chemistry of the treated cellulosic fibers may be manifested as a desirable functionality, such as acting as an astringent when the treating cation is, for example, alum or aluminum acetate. Such effect provides certain favorable functions to the fibers and products produced from those fibers when contacted with skin or wounds, such as, but not limited to, encouraging blood clotting by prompting blood vessel contraction.
It is a further aspect of certain embodiments of the instant invention that the surface activity of the so treated cellulosic fibers enhances the compatibility of those fibers with quaternary ammonium compounds (QAC). Untreated natural or synthetic cellulosic fibers, including bast fibers, react negatively with QAC's and neutralize the QAC sanitizing effectiveness. Treated fibers of certain embodiments of the present disclosure, and products produced from those fibers, allow the sanitizing functionality of the QAC to be substantially unaffected where such function is useful for wiping products for the purpose of sanitizing surfaces with which the product comes in contact.
While bast fibers are well-known cellulosic fibers, and have use in a variety of products, it has been discovered that imposing crimp to those fibers, by mechanical or chemical means, has certain aesthetic and performance benefits to products manufactured from the crimped bast fibers. Therefore, it is an aspect of certain embodiments of the instant invention that, when bast fibers are utilized, those bast fibers have been treated to impose crimp either before or after the cationic compound treatment. Such bast fibers include, but are not limited to, kenaf, nettle, Spanish broom, bamboo, ramie, hemp, and flax. The means for imposing crimp may be chemical or mechanical.
It is a further aspect of certain embodiments of the present invention that the bast fibers described, have been treated such that the natural pectin, which adheres the individual fibers together in bundles as recovered from the plant source, has been removed in sufficient measure that the bast fibers are individualized as used in the nonwoven fabric forming processes to produce the nonwoven fabric.
It is a further aspect of certain embodiments of the instant invention that the cationic compound treatment may be used to modify the surface chemistry or surface behavior of natural or synthetic protein fibers as well, including but not limited to, animal hair, fur or wool, silk (including silk produced by various insects or arachnids, such as spiders, and synthetic silk).
Products of certain embodiments of the invention may include, but are not limited to, bulk forms of fibers such bales, bolls, balls, tufts, mats, batt and webs, as well as single fabrics produced from well-known means including weaving, knitting, braiding, and nonwovens. The term nonwovens is understood to encompass the variety of fabric forming technologies, including but not limited to, wetlaid, airlaid, drylaid with associated bonding means which includes but are not limited to thermal bonding, chemical bonding and adhesive bonding. The invention anticipates composite and complex product constructs which may comprise one or more components. In those composite and complex product constructs, multiple components may be drawn from more than one type of composition or construct listed herein.
In certain embodiments, the present invention relates to surface treatments of cellulosic fibers with a cationic compound which renders certain functionalities to the fibers so treated. More specifically, the invention relates to cellulosic fibers that are treated with alum or aluminum acetate, thereby providing an astringent functionality to the fibers and products containing those fibers, where such function may be useful in certain skin care and wound care products. Certain other advantages are associated with the treatment of cellulosic fibers with cationic compound solutions, such as an improved compatibility with quaternary ammonium compounds, providing in certain embodiments a sanitizing functionality to the fibers and products made with those fibers, and possibly some level of flame resistance. Protein fibers have been found to show similar functionalization related to the same type of cationic compound solution surface treatments.
The present disclosure includes, without limitation, the following embodiments.
Embodiment 1: A fibrous material comprising a plurality of fibers, said fibers being natural or synthetic cellulosic fibers or natural or synthetic protein fibers, and wherein said fibers are treated with one or more of a cationic compound and an alcohol.
Embodiment 2: The fibrous material of embodiment 1, wherein the treated fibers exhibit one or more of improved astringent properties, improved compatibility with quaternary ammonium compounds, and improved flame resistance, as compared to the fibers before treatment.
Embodiment 3: The fibrous material of any one of embodiments 1 to 2, wherein the cationic compound treatment provides a dry add-on of the cationic compound of up to 20% of the fiber weight.
Embodiment 4: The fibrous material of any one of embodiments 1 to 3, wherein the cationic compound is in the form of a solution wherein the concentration of the cationic compound is at least 0.0001% by weight and up to the saturation limit of the cationic compound or up to 99.99% by weight, based on the total weight of the solution.
Embodiment 5: The fibrous material of any one of embodiments 1 to 4, wherein the cationic compound is selected from the list of alkali metals salts, alkali earth metals salts, and salts of transition metals or post-transition metals such as aluminum, copper, zinc, manganese, and iron.
Embodiment 6: The fibrous material of any one of embodiments 1 to 5, wherein the cationic compound is a salt selected from the group consisting of sulfates, sulfites, acetates, carbonates, chlorides, hydroxides, phosphates, and nitrates.
Embodiment 7: The fibrous material of any one of embodiments 1 to 6, wherein the cationic compound is an alkali salt and produces a basic solution when dissolved in water, such as sodium carbonate, potassium carbonate, sodium acetate, or calcium carbonate.
Embodiment 8: The fibrous material of any one of embodiments 1 to 7, wherein the cationic compound is an acidic salt and produces an acidic solution when dissolved in water, such as aluminum chloride, aluminum acetate, aluminum sulfate, potassium aluminum sulfate, or ammonium chloride.
Embodiment 9: The fibrous material of any one of embodiments 1 to 8, wherein the cationic compound is a neutral salt and produces neither basic nor acidic solution when dissolved in water, such as sodium chloride.
Embodiment 10: The fibrous material of any one of embodiments 1 to 9, wherein the cationic compound is a quaternary ammonium compound.
Embodiment 11: The fibrous material of any one of embodiments 1 to 10, wherein said quaternary ammonium compound has a positively charged polyatomic ion of the structure NR4+, wherein each R is independently selected from the group consisting of hydrogen, an alkyl group, and an aryl group, such as benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, and domiphen bromide.
Embodiment 12: The fibrous material of any one of embodiments 1 to 11, wherein the cationic compound is a surfactant.
Embodiment 13: The fibrous material of any one of embodiments 1 to 12, wherein the surfactant has cationic head groups, such as primary, secondary, or tertiary amines.
Embodiment 14: The fibrous material of any one of embodiments 1 to 13, wherein the cationic compound comprises alum or aluminum acetate.
Embodiment 15: The fibrous material of any one of embodiments 1 to 14, wherein the plurality of fibers is pre-treated with an alcohol followed by cationic compound treatment.
Embodiment 16: The fibrous material of any one of embodiments 1 to 15, wherein the alcohol is ethanol.
Embodiment 17: The fibrous material of any one of embodiments 1 to 16, wherein the plurality of fibers is post-treated with a polymer or resin.
Embodiment 18: The fibrous material of any one of embodiments 1 to 17, wherein the polymer or resin is derived from either petroleum or renewable sources, such as polyhydroxy alkanoates (e.g., PHB), aliphatic polyesters (e.g., polybutylene succidate) and co-polyesters, aromatic polyesters (e.g., polybutylene adipate terephthalate) and co-polyesters, polyester amides, polylactic acid, polyvinyl alcohol, poly e-caprolactone, thermoplastic starches, modified starches, proteins, and chitosan.
Embodiment 19: The fibrous material of any one of embodiments 1 to 18, wherein the polymer or resin is dispersed in a liquid, such as water.
Embodiment 20: The fibrous material of any one of embodiments 1 to 19, wherein the polymer or resin is either thermoplastic or thermosetting.
Embodiment 21: The fibrous material of any one of embodiments 1 to 20, wherein the plurality of fibers are natural or synthetic cellulosic fibers selected from the group consisting of viscose, acetate, rayon, lyocell, and cotton.
Embodiment 22: The fibrous material of any one of embodiments 1 to 21, wherein the plurality of fibers is a blend of two or more fiber types.
Embodiment 23: The fibrous material of any one of embodiments 1 to 22, wherein the fiber blend is 5% to 100% by weight of the natural or synthetic cellulosic fibers.
Embodiment 24: The fibrous material of any one of embodiments 1 to 23, wherein the fiber blend may contain up to 95% by weight of natural or synthetic fibers that are non-cellulosic fibers.
Embodiment 25: The fibrous material of any one of embodiments 1 to 24, wherein the plurality of fibers has a mean length of greater than about 1 mm.
Embodiment 26: The fibrous material of any one of embodiments 1 to 25, wherein the plurality of fibers has been mechanically or chemically treated to remove surface impurities prior to treatment with the cationic compound.
Embodiment 27: The fibrous material of any one of embodiments 1 to 26, wherein said cationic compound comprises alum.
Embodiment 28: The fibrous material of any one of embodiments 1 to 27, wherein the alum is potassium aluminum sulfate.
Embodiment 29: The fibrous material of any one of embodiments 1 to 28, wherein the fibrous material is selected from woven, knitted or nonwoven fabrics, or composites of two or more of said fabrics.
Embodiment 30: The fibrous material of any one of embodiments 1 to 29, wherein the fibrous material is in a bulk fiber form selected from the group consisting of a mat, batt, bale, tuft, boll, ball, and bundle.
Embodiment 31: The fibrous material of any one of embodiments 1 to 30, wherein the fibrous material is in the form of a composite of two or more components, wherein each component may be in the form of a plurality of fibers or a fabric.
Embodiment 32: The fibrous material of any one of embodiments 1 to 31, wherein the fibrous material is selected from the group consisting of a wipe or wiping cloth, a medical product, a health and wellness product, and a wound care product.
Embodiment 33: The fibrous material of any one of embodiments 1 to 32, wherein the presence of the cationic compound is durable to water rinsing and detergent washing of the plurality of fibers.
Embodiment 34: The fibrous material of any one of embodiments 1 to 33, wherein the natural or synthetic cellulosic fibers comprise at least about 5% bast fibers by weight, where said bast fibers have been chemically or mechanically crimped.
Embodiment 35: The fibrous material of any one of embodiments 1 to 34, wherein the fibrous material is blended with one or more natural or synthetic cellulosic fibers including, but not limited to, viscose, acetate, rayon, lyocell, cotton, flax, hemp, jute, ramie, bamboo, nettle, Spanish broom, kenaf plants, and wherein the content of said bast fibers is at least 5% by weight.
Embodiment 36: The fibrous material of any one of embodiments 1 to 35, where the fibrous material is blended with one or more natural or synthetic fibers that are non-cellulosic, where the content of said bast fibers is at least 5% by weight.
Embodiment 37: The fibrous material of any one of embodiments 1 to 36, wherein the natural or synthetic protein fibers are selected from the group consisting of animal hair, wool, fur, and silk.
Embodiment 38: The fibrous material of any one of embodiments 1 to 37, wherein the natural or synthetic cellulosic fibers are lignocellulosic fibers, such as fibers with a lignin concentration of about 0.001% to about 50% by weight.
Embodiment 39: A method for imparting improved compatibility with quaternary ammonium compounds to a fibrous material, comprising: providing a fibrous material comprising a plurality of fibers, the fibers being natural or synthetic cellulosic fibers or natural or synthetic protein fibers; treating the fibrous material with one or more of a cationic compound and an alcohol to impart improved compatibility with quaternary ammonium compounds; optionally, further treating the treated fibrous material with a polymer or resin.
Embodiment 40: The method of embodiment 39, wherein the treatment step provides a dry add-on of cationic compound of up to 20% of the fiber weight.
Embodiment 41: The method of any one of embodiments 39 to 40, wherein the cationic compound is in the form of a solution wherein the concentration of the cationic compound is at least 0.0001% by weight and up to the saturation limit of the cationic compound.
Embodiment 42: The method of any one of embodiments 39 to 41, wherein the cationic compound is an alkali salt and produces a basic solution when dissolved in water, such as sodium carbonate, potassium carbonate, sodium acetate, or calcium carbonate.
Embodiment 43: The method of any one of embodiments 39 to 42, wherein the pH of the basic solution is adjusted to between about 7 to about 12 prior to or during said treatment step.
Embodiment 44: The method of any one of embodiments 39 to 43, wherein the cationic compound is an acidic salt and produces an acidic solution when dissolved in water, such as aluminum chloride, aluminum sulfate, potassium aluminum sulfate, or ammonium chloride.
Embodiment 45: The method of any one of embodiments 39 to 44, wherein the pH of the acidic solution is adjusted to between about 4 to about 7 prior to or during said treatment step.
Embodiment 46: The method of any one of embodiments 39 to 45, wherein the cationic compound is a neutral salt and produces neither basic nor acidic solution when dissolved in water, such as sodium chloride.
Embodiment 47: The method of any one of embodiments 39 to 46, wherein the pH of the solution is adjusted to between about 5 to about 9 prior to or during said treatment step
Embodiment 48: The method of any one of embodiments 39 to 47, wherein treatment step (b) comprises first treating the fibrous material with an alcohol and then treating the fibrous material with a cationic compound.
Embodiment 49: The method of any one of embodiments 39 to 48, wherein the cationic compound is selected from the group consisting of cationic surfactants, quaternary ammonium compounds, alkali metals salts, alkali earth metals salts, and salts of aluminum, copper, zinc, manganese, and iron.
Embodiment 50: A fibrous material comprising a plurality of fibers, said fibers being natural or synthetic cellulosic fibers or natural or synthetic protein fibers, and wherein said fibers are treated with at least one cationic compound.
Embodiment 51: The fibrous material of embodiment 50, wherein the cationic compound is selected from the list of alkali metal salts, alkali earth metal salts, salts of transition or post-transition metals, and ionic liquids.
Embodiment 52: The fibrous material of any one of embodiments 50 to 51, wherein the cationic compound is a salt of aluminum, copper, zinc, manganese, or iron.
Embodiment 53: The fibrous material of any one of embodiments 50 to 52, wherein the cationic compound is a salt selected from the group consisting of sulfates, sulfites, acetates, carbonates, chlorides, hydroxides, phosphates, and nitrates.
Embodiment 54: The fibrous material of any one of embodiments 50 to 53, wherein the cationic compound is an aluminum salt.
Embodiment 55: The fibrous material of any one of embodiments 50 to 54, wherein the aluminum salt is selected from the group consisting of aluminum chloride, aluminum sulfate, potassium aluminum sulfate, and aluminum acetate.
Embodiment 56: The fibrous material of any one of embodiments 50 to 55, wherein the cationic compound is an ionic liquid comprising a cation selected from the group consisting of imidazolium, ammonium, pyrrolidinium, pyridinium, and phosphonium.
Embodiment 57: The fibrous material of any one of embodiments 50 to 56, wherein the cationic compound comprises polydiallyldimethylammonium chloride.
Embodiment 58: The fibrous material of any one of embodiments 50 to 57, wherein the cationic compound is a polymer (including oligomers and co-polymers) comprising one or more quaternary ammonium groups.
Embodiment 59: The fibrous material of any one of embodiments 50 to 58, wherein the polymer is dicyandiamide, formaldehyde, ammonium chloride polymer.
Embodiment 60: The fibrous material of any one of embodiments 50 to 59, wherein the dry add-on of the cationic compound is up to about 20% of the dry fiber weight.
Embodiment 61: The fibrous material of any one of embodiments 50 to 60, wherein the dry add-on of the cationic compound is up to about 10% of the dry fiber weight (such as up to about 5% or up to about 2.5% or up to about 1.0% or up to about 0.5%).
Embodiment 62: The fibrous material of any one of embodiments 50 to 61, wherein the fibrous material is substantially (or completely) free of carboxymethylcellulose.
Embodiment 63: The fibrous material of any one of embodiments 50 to 62, wherein the fibrous material is further treated with one or more of an alcohol, a base, a quaternary ammonium compound, and a polymer or resin.
Embodiment 64: The fibrous material of any one of embodiments 50 to 63, wherein the fibrous material is further treated with one or more of a quaternary ammonium compound and a carbonate or bicarbonate base.
Embodiment 65: The fibrous material of any one of embodiments 50 to 64, wherein the fibrous material exhibits improved compatibility with quaternary ammonium compounds as compared to the same fibrous material untreated with a cationic compound.
Embodiment 66: The fibrous material of any one of embodiments 50 to 65, wherein the fibrous material is characterized by greater than 40% (or 50% or 60% or 70% or 80% or 90%) quaternary ammonium compound retention in a benzalkonium chloride solution following immersion of the fibrous material in the benzalkonium chloride solution at a concentration of 1000 ppm for 5 minutes at room temperature, as determined by ultraviolet spectra of the benzalkonium chloride solution.
Embodiment 67: The fibrous material of any one of embodiments 50 to 66, wherein the plurality of fibers comprise natural or synthetic cellulosic fibers selected from the group consisting of viscose, acetate, rayon, lyocell, cotton, bast fibers, and blends thereof.
Embodiment 68: The fibrous material of any one of embodiments 50 to 67, wherein the fibrous material comprises bast fibers in an amount of at least about 5% by weight, based on the total dry weight of the fibrous material (e.g., at least about 10% or 20% or 30% or 40% or 50% or 60% or 70% or 80% or 90%).
Embodiment 69: The fibrous material of any one of embodiments 50 to 68, wherein the bast fibers are selected from the group consisting of kenaf, nettle, Spanish broom, jute, bamboo, ramie, hemp, flax, and blends thereof.
Embodiment 70: The fibrous material of any one of embodiments 50 to 69, wherein the fibrous material is selected from woven, knitted or nonwoven fabrics, or composites of two or more of said fabrics.
Embodiment 71: The fibrous material of any one of embodiments 50 to 70, wherein the fibrous material is in a bulk fiber form selected from the group consisting of a mat, batt, bale, tuft, boll, ball, and bundle; or in a product form selected from the group consisting of a wipe or wiping cloth, a medical product, a health and wellness product, and a wound care product.
Embodiment 72: A method for imparting improved compatibility with quaternary ammonium compounds to a fibrous material, comprising: providing a fibrous material comprising a plurality of fibers, the fibers being natural or synthetic cellulosic fibers or natural or synthetic protein fibers; optionally, pre-treating the fibrous material with a base; treating the fibrous material with at least one cationic compound to impart improved compatibility with quaternary ammonium compounds; and optionally, further treating the treated fibrous material with a polymer or resin.
Embodiment 73: The method of embodiment 72, wherein treating with a cationic compound comprises treating the fibrous material with a treatment liquid comprising the cationic compound at a concentration of from 0.1% up to about 40% wof (e.g., about 5% to about 30% or about 10% to about 25%).
Embodiment 74: The method of any one of embodiments 72 to 73, comprising treating the fibrous material with a treatment liquid comprising the cationic compound at a concentration of at least 20% wof (or at least 25% or at least 30% or at least 35% or at least 40%).
Embodiment 75: The method of any one of embodiments 72 to 74, wherein treating the fibrous material with at least one cationic compound comprises treating the fibrous material with an aqueous solution, a slurry, a solid, or an ionic liquid containing the at least one cationic compound.
Embodiment 76: The method of any one of embodiments 72 to 75, wherein the cationic compound is selected from the list of alkali metal salts, alkali earth metal salts, and salts of transition or post-transition metals.
Embodiment 77: The method of any one of embodiments 72 to 76, wherein the cationic compound is a salt of aluminum, copper, zinc, manganese, or iron.
Embodiment 78: The method of any one of embodiments 72 to 77, wherein the cationic compound is a salt selected from the group consisting of sulfates, sulfites, acetates, carbonates, chlorides, hydroxides, phosphates, and nitrates.
Embodiment 79: The method of any one of embodiments 72 to 78, wherein the cationic compound is an aluminum salt.
Embodiment 80: The method of any one of embodiments 72 to 79, wherein the aluminum salt is selected from the group consisting of aluminum chloride, aluminum sulfate, potassium aluminum sulfate, and aluminum acetate.
Embodiment 81: The method of any one of embodiments 72 to 80, wherein the cationic compound is an ionic liquid comprising a cation selected from the group consisting of imidazolium, ammonium, pyrrolidinium, pyridinium, and phosphonium.
Embodiment 82: The method of any one of embodiments 72 to 81, wherein the cationic compound comprises polydiallyldimethylammonium chloride.
Embodiment 83: The method of any one of embodiments 72 to 82, wherein the cationic compound is a polymer (including oligomers and co-polymers) comprising one or more quaternary ammonium groups.
Embodiment 84: The method of any one of embodiments 72 to 83, wherein the polymer is dicyandiamide, formaldehyde, ammonium chloride polymer.
Embodiment 85: The method of any one of embodiments 72 to 84, wherein the fibrous material is substantially free (or completely free) of carboxymethylcellulose.
Embodiment 86: The method of any one of embodiments 72 to 85, wherein the pre-treatment (b) comprising treating the fibrous material with a carbonate or bicarbonate base.
Embodiment 87: The method of any one of embodiments 72 to 86, wherein the fibrous material is further treated with an alcohol prior to treatment with the cationic compound.
Embodiment 88: The method of any one of embodiments 72 to 87, wherein the alcohol is ethanol or isopropyl alcohol.
Embodiment 89: The method of any one of embodiments 72 to 88, wherein the fibrous material is further treated with at least one quaternary ammonium compound.
Embodiment 90: The method of any one of embodiments 72 to 89, wherein the fibrous material is treated with the at least one cationic compound and the at least one quaternary ammonium compound simultaneously.
Embodiment 91: The method of any one of embodiments 72 to 90, further comprising mechanically or chemically treating the fibrous material to remove surface impurities prior to treatment with the cationic compound.
Embodiment 92: The method of any one of embodiments 72 to 91, wherein the polymer or resin is dispersed in a liquid.
Embodiment 93: The method of any one of embodiments 72 to 92, wherein the polymer or resin is a polyhydroxy alkanoate, aliphatic polyester or co-polyester, aromatic polyester or co-polyester, polyester amide, polylactic acid, polyvinyl alcohol, poly e-caprolactone, thermoplastic starch, modified starch, protein, or chitosan.
Embodiment 94: The method of any one of embodiments 72 to 93, wherein the fibrous material is a nonwoven material.
Embodiment 95: The method of any one of embodiments 72 to 94, comprising: providing the nonwoven material in a roll; feeding the nonwoven material from the roll through a coating tray containing a liquid comprising the cationic compound such that the cationic compound contacts the nonwoven material; calendaring the nonwoven material to remove excess liquid; drying the nonwoven material to decrease liquid holdup within the nonwoven material to form a treated nonwoven material; and optionally, winding the treated nonwoven material back into roll form.
Embodiment 96: The method of any one of embodiments 72 to 95, wherein the cationic compound is polydiallyldimethylammonium chloride or dicyandiamide, formaldehyde, ammonium chloride polymer.
Embodiment 97: The method of any one of embodiments 72 to 96, wherein the concentration of cationic compound in the liquid is between about 0.5% to about 10% by weight, based on the total weight of the liquid (e.g., about 0.5% to about 5% or about 1% to about 4% or less than about 5% or less than about 4%).
Embodiment 98: The method of any one of embodiments 72 to 97, wherein the dry add-on of cationic compound in the treated nonwoven material is up to about 20% of the dry fiber weight (such as up to about 15% or up to about 10% or up to about 5%).
Embodiment 99: The method of any one of embodiments 72 to 98, wherein the nonwoven material and the treated nonwoven material is substantially free (or completely free) of carboxymethylcellulose.
Embodiment 100: The method of any one of embodiments 72 to 99, wherein the nonwoven material comprises at least about 5% by weight of bast fibers (e.g., at least about 10% or 20% or 30% or 40% or 50% or 60% or 70% or 80% or 90%).
These and other features, aspects, and advantages of the disclosure will be apparent from the following detailed description. The invention includes any combination of two, three, four, or more of the above-noted embodiments as well as combinations of any two, three, four, or more features or elements set forth in this disclosure, regardless of whether such features or elements are expressly combined in a specific embodiment description herein. This disclosure is intended to be read holistically such that any separable features or elements of the disclosed invention, in any of its various aspects and embodiments, should be viewed as intended to be combinable unless the context clearly dictates otherwise. Other aspects and advantages of the present invention will become apparent from the following.
In order to provide an understanding of embodiments of the invention, reference is made to the appended drawings. The drawings are exemplary only, and should not be construed as limiting the invention. The disclosure described herein is illustrated by way of example and not by way of limitation in the accompanying figures.
The following definitions are presented for use in the interpretation of the claims and specification of the instant invention. Terms such as “comprising”, “comprises”, “including”, “including but not limited to”, “contains”, “containing” are not to be considered as limiting or exclusive as related to the claimed invention. “A” and “an” are not be considered as indication enumeration when preceding an element or component. The terms “invention”, “present invention” or “instant invention” are not limiting terms and are used to convey and incorporate all aspects described and discussed in the claims and the specification. The term “about” used as a modifier of a quantity refers to variations as are known and understood to occur in measuring and handling procedures as are known to those skilled in the arts of textile science and engineering. Additional definitions of technical terms and references follow.
Cellulosics, and cellulosic fibers refer to natural fibers or to synthetic fibers which are chemically ethers or esters of cellulose. Such natural fibers are obtained from the bark, wood, leaves, stems, or seeds of plants. Synthetic cellulosic fibers are manufactured from digested wood pulp and may include substituted side groups to the cellulose molecule that provide specific properties to those fibers.
Bast fibers are obtained from the phloem or bast from the stem of certain plants, including but not limited to, jute, kenaf, flax, hemp, and ramie. The bast fibers are initially recovered as bundles of individual fibers, which are adhered by pectin, which must be subsequently removed to some degree to allow the bast fibers to be processed further.
Crimp is the naturally occurring convolution of waviness of a fiber, or that same property induced by chemical or mechanical means, such as crimping of synthetic fibers. The imposition of crimp to a specific frequency, as defined by a number of crimps per unit of fiber length.
Natural fibers are those sourced directly from plants, animals, or minerals, noting that such fibers may require specific pre-processing in order to render them useful for textile manufacturing purposes. Synthetic fibers are those produced through polymerization processes, using naturally occurring and sustainably sourced raw materials or petroleum derived raw materials.
Staple fibers are fibers with a discrete length and may be natural or synthetic fibers. Continuous fibers have an indeterminate or difficult to measure length, such as silk or those from certain synthetic fiber spinning processes. Fibers of any length may be cut into discrete lengths and that cut product is then referred to as a staple fiber.
Airlaid, sometimes referred to as air laid, is a processes for producing a fibrous mat or batt using short or long staple fibers, or blends of the same. In this process, air is used to transfer the fibers from the fiber opening and aligning section of the process and to then convey those fibers to a forming surface where the fibrous mat or batt is collected and then subjected to a further step of bonding or consolidating to produce an airlaid nonwoven fabric.
Drylaid is a process for producing a fibrous mat or batt by a process using mechanical fiber opening and alignment, such as carding, where the fibrous mat or batt is transferred by mechanical means, rather than by means of air, to a conveyor surface, where the fibrous mat or batt is then subjected to a further step of bonding or consolidating to produce a drylaid nonwoven fabric.
Wetlaid, sometimes referred to as wet laid, is a process for producing a fibrous sheet through means similar to paper making where the fibers are suspended in an aqueous medium and the web is formed by filtering the suspension on a conveyor belt or perforated drum. Depending on the end use application and fibers used to produce the fabric, some means of bonding or consolidating may be required to achieve final properties in the fabric.
Bonding or consolidation of fibrous mats or batts is a processing step that is common among the various technologies for producing nonwoven fabrics. The means of bonding or consolidation are commonly considered as being mechanical, thermal, or adhesive, with several distinct methodologies existing under each of those headings. In general, mechanical means rely on creating entanglements between and among fibers to produce desired physical properties, where needlepunch and hydroentangling are nonexclusive examples of those means. Thermal bonding uses the thermoplastic properties of at least some fibers included in the fabric, such that the application of heat with or without pressure causes a portion of the fibers to soften and deform around each other and/or to melt and form a solid attachment between and among fibers at points of crossover when the thermoplastic material has cooled and solidified. Adhesive means use the application of adhesive in some form to create a physical bond between and among fibers at points of crossover, such means nonexclusively including liquid adhesives, dry adhesives, and hot melt adhesives. These adhesives may be applied to mats or batts as sprays and foams, or via methods known in the art including but not limited to dip-and-squeeze or gravure roll.
A percentage by weight (e.g., a percentage by weight of fiber, expressed as “% wof”), in reference to a fiber or fabric, is the weight of given solid component divided by the total weight of the fiber or fabric, expressed as a percentage of the total dry fiber or fabric weight.
Strength-to-weight ratio is an expression of a normalized tensile strength value for a fabric where the tensile strength of the fabric can then be considered relative to similar fabrics without the impact of basis weight differences between or among sample fabrics or grades of fabrics. Because basis weight alone can influence tensile strength values for a given fabric, the strength-to-weight ratio allows for an assessment of the impact on the strength of a fabric contributed by the inclusion of a specific fiber or a change in the process parameters, as non-exclusive examples of the usefulness of that metric.
Loft relies upon the properties of bulk and resilience for a fabric. In technical terms, bulk is the inverse of density, while in common usage bulk is equated to simple fabric thickness. Resiliency is the ability of a fabric to resist permanent compression, with loss of volume, following application of an areal load.
Antimicrobial efficacy is a consideration of the ability of a product to reduce bacterial, viral or fungal contamination, either as the bioburden of the product itself or as the product is used to clean or disinfect a secondary or tertiary material or product. The property of antimicrobial function can be imparted to textile fabrics in a number of ways utilizing a variety of chemical and biochemical materials.
Quaternary ammonium compounds (QAC) are among the most widely used antimicrobial treatments available, having good stability and surface activity, low odor and reactivity with other cleaning agents, and good toxicology results. QACs are active against most bacteria, as well as some virus forms and certain fungi. Further, QACs are readily applied to surfaces, including the surfaces of fibers in a fabric construction, where it may be retained by those surfaces and also transferred from the fibers to other surfaces for the purpose of cleaning or disinfecting. While synthetic fiber surfaces are known to be essentially non-reactive with QACs, some cellulosic fibers, including bast fibers, react with QACs thereby reducing the efficacy of the QAC as a disinfecting and cleaning agent when those fibers are used in fabrics intended as wiping materials. Generally, QACs have a positively charged polyatomic ion of the structure NR4+, wherein each R is independently selected from the group consisting of hydrogen, an alkyl group, and an aryl group, such as benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, and domiphen bromide.
Cationic compounds, for the purposes of this invention, are any chemicals and polymers (including oligomers and co-polymers) characterized by one or more cationic groups and which have at least one positively charged group in their chemical structure. Such compounds can be provided in a variety of forms, including in the form of an aqueous solution or slurry, a solid, or an ionic liquid. Examples of solutions containing cationic compounds include, but are not limited to, alum solutions, aluminum acetate solutions (e.g., such as aluminum ethanoate, aluminum triacetate, aluminum diacetate, aluminum monoacetate), and polydiallyldimethylammonium chloride (commonly referred to as “PDDR” and/or “PolyDADMAC” and/or “Polyquaternium-6”). Generally, the cationic treatment material as a whole may be characterized as being cationic or neutral, so long as at least one cationic compound is present. Alum is an example of a cationic compound, where alum is a hydrated double sulfate of aluminum and potassium. However, alum solutions are typically neutral despite the presence of Al3+ cations therein. Solutions of aluminum acetate are sometimes formed from commercially available powder mixtures of aluminum sulfate tetradecahydrate and calcium acetate monohydrate. Some cationic compounds, such as aluminum acetate, have limited solubility in water, so no particular water solubility level is required to practice the present invention. In certain embodiments, the cationic compound is characterized by the presence of one or more quaternary ammonium groups, including any QACs noted herein for use as disinfectants.
Generally, the type of cationic compounds and solutions containing those cationic compounds may vary. For example, the solution may contain a cationic compound selected from the group consisting of alkali metal salts, alkali earth metal salts, sulfates, sulfites, acetates, carbonates, chlorides, hydroxides, phosphates, and nitrates, and salts of aluminum, copper, zinc, manganese, and iron. In some embodiments, the solution may contain a cationic compound that is an alkali salt and produces a basic solution when dissolved in water, such as sodium carbonate, potassium carbonate, sodium acetate, or calcium carbonate. In some embodiments, the solution may contain a cationic compound that is an acidic salt and produces an acidic solution when dissolved in water, such as aluminum chloride, aluminum sulfate, potassium aluminum sulfate, or ammonium chloride. In some embodiments, the solution may contain a cationic compound that is a neutral salt and produces neither basic nor acidic solution when dissolved in water, such as sodium chloride. In some embodiments, the solution may contain a cationic surfactant, e.g., such as a surfactant having cationic head groups, such as primary, secondary, and/or tertiary amines. In some embodiments, cationic compounds may include, for example, ionic liquids, which are typically ionic and liquid at room temperature (also known as liquid electrolytes, ionic melts, ionic fluids, or liquid salts), with example cations of such liquids including imidazolium, ammonium, pyrrolidinium, pyridinium, and phosphonium. Ionic liquids can include polymerized ionic liquids, also known as poly ionic liquids, polyquaternium, cationic polymers, or cationic polyelectrolytes.
In certain embodiments, the cationic compound is in the form of a positively charged polymer (including oligomers and co-polymers). For example, such cationic polymers may include one or more quaternary ammonium groups, or one or more other cations such as imidazolium, pyrrolidinium, pyridinium, or phosphonium groups. In one embodiment, the cationic polymer is a cationic starch such as a starch modified with quaternary ammonium groups. In some embodiments, the cationic polymer number average molecular weight can be between about 100 to about 500,000 Da. In certain embodiments, it can be advantageous to utilize lower polymer molecular weights in order to enhance dispersion of the polymer throughout a fibrous material. Example ranges of molecular weight can include less than about 100,000 Da, or less than about 75,000 Da, or less than about 50,000 Da, or less than about 10,000 Da, or less than about 5,000 Da (e.g., about 100 to about 100,000 Da or about 100 Da to about 50,000 Da or about 100 Da to about 25,000 Da).
In some embodiments, the cationic compound can include any chemical, polymer, co-polymer containing or originating from amines (e.g., containing or originating from an NR3 structure, where each R group is hydrogen, alkyl, or aryl in any combination), amine derivatives, amino groups, guanidine, guanidine derivatives, cyanoguanidine, cyanoguanidine derivatives, guanidine cyano-polymer and derivatives, guanidine cyano-polymer with ammonium chloride, and guanidine cyano-polymer with ammonium chloride and formaldehyde. In some embodiments, the polymer can be characterized as a polyamine, a co-polymer of polyamines, a cationic polyamine, a polyamide, a co-polymer of polyamides, or a cationic polyamide. In certain embodiments, the polymer is dimethylamine-epichlorohydrin copolymer or polyhexanide (also known as polyhexamethylene biguanide or PHMB). Example cationic compounds are available from Kemira Oyj of Helsinki, Finland, under trade names such as LEVOGEN and SUPERFLOC.
In one particular embodiment, the cationic compound is LEVOGEN available from Kemira Oyj. This chemical has CAS No. 55295-98-2 and is a positively charged copolymer comprising dicyandiamide (i.e., cyanoguanidine) residues, formaldehyde residues, and ammonium chloride residues. Other names include dicyandiamide, formaldehyde, ammonium chloride polymer and guanidine, cyano-, polymer with ammonium chloride and formaldehyde.
Flame resistance in fiber-based products are those treated with chemical agents or finishes to make them resistant to burning when impinged by a flame source.
An astringent causes the contraction of skin cells or other body tissues upon contact, such as facial pores and blood vessels. Generally, fibers or fabrics having astringent properties can provide certain favorable functions when contacted with skin or wounds, such as, but not limited to, encouraging blood clotting by prompting blood vessel contraction.
Dry add-on is a term that describes the residual amount of a treating chemical or chemicals that remains on the treated material after moisture is removed and the treated product is in a dried state. It may be expressed, as an example, as grams of chemical treatment/gram of untreated material, as grams of added weight following treatment, or as a percentage of weight gained based on the untreated weight.
Durable or durability relates to a fiber or product property modification that is not depleted to a level that is nonfunctional nor inactivated after a single use of said fiber material or fiber-based product.
Treatment Methods
One aspect of the present disclosure relates to the surface modification of cellulosic or protein fibers (and products formed from those fibers such as fabrics) via a treatment with a cationic compound, such as, but not limited to, alum, aluminum acetate, and PDDA. As noted above, untreated natural or synthetic cellulose or protein fibers, including bast fibers, react negatively with QACs and neutralize at least a portion of the QAC sanitizing effectiveness. However, such treatment (e.g., with a solution containing a cationic compound) imposes a change in the surface activity or reactivity of the fibers so treated. The inventors have realized certain advantageous features and performance functionalities to be associated with such treatment, including an improved compatibility with other treatments, such as the ability to successfully treat cellulosic or protein fibers secondarily with a QAC. For example, in certain embodiments, treated fibers, and products produced from those fibers, allow the sanitizing functionality of the QAC to be substantially unaffected or even improved.
Some embodiments of the present invention relate to methods for imparting improved compatibility with quaternary ammonium compounds (QACs) to a fibrous material, in particular. For example, such methods may comprise providing a fibrous material comprising a plurality of fibers as described herein (e.g., such as natural or synthetic cellulosic fibers, natural or synthetic protein fibers, bast fibers, and the like) and treating the fibrous material with a solution containing cationic compounds (e.g., alum, aluminum acetate, and/or PDDA). The means of treating the fibers or products containing the fibers may include those known in the art, e.g., such as applying the solutions containing cationic compounds with a kiss roll or a gravure roll (e.g., in the form of a coating), a soaking tank, or a spray, which may be followed by a press roll or a vacuum step to remove excess moisture. It is also possible to apply a water rinse either before or after an initial press roll or vacuum box where the water application step would be followed by an additional moisture removal step. The treatment may include multiple rinse and moisture removal steps prior to a drying step which removes moisture to a level that renders the fibers or product ready for further processing or packaging for use. In some embodiments, cationic compounds may also be applied as a solid to the fibers or fiber-based products of the invention when they are in a wet form.
The cationic compounds may be applied to the fibers or fiber-based products in various amounts. For example, the concentration of the cationic compound in a treatment liquid (e.g., a solution or slurry) may vary. For example, the concentration of the solution containing cationic compound may be at least about 0.0001% by weight and up to about 99.99% by weight of cationic compound, based on the total weight of the solution. In some embodiments, the concentration of the solutions containing cationic compounds may be at least about 1% by weight, at least about 10% by weight, at least about 25% by weight, at least about 50% by weight, at least about 75% by weight, or at least about 90% by weight of cationic compound.
The concentration of cationic compound in a treatment liquid can also be expressed as a % wof. For example, the fibers or fiber-based products may be treated with a cationic compound at a concentration of from about 0.1% up to about 10% wof, up to about 20% wof, up to about 30% wof, or up to about 40% wof. In some embodiments, for example, the fibers or fiber-based products may be treated with a cationic compound at a concentration of about 1% to about 50% wof, about 10% to about 40% wof, or about 20% to about 30% wof. In certain embodiments, the concentration of the cationic compound is at least about 1% wof, at least about 5% wof, at least about 10% wof, at least about 15% wof, or at least about 20% wof. Note that reference to the cationic compound within a treatment liquid does not suggest that the cationic compound will be present only in compound form. The cationic compound can be fully or partially ionized in the treatment liquid (e.g., an aqueous solution).
The amount of cationic compound within the fibrous structure following treatment and drying is sometimes referred to as dry add-on, and can vary significantly based on the type and structure of the fibrous material and the type and structure of the cationic compound. In certain embodiments, the dry add-on is up to about 20% by dry weight of the fibrous material, such as about 0.1 to about 15% by dry weight of the fibrous material. In certain embodiments, the dry add-on is less than about 15% by dry weight of the fibrous material, such as less than about 10% or less than about 5% or less than about 2.5% or less than about 1.0% or less than about 0.5%.
In some embodiments, the fibers may be treated with the cationic compound utilizing the same equipment as is used for cleaning the fibers, for example, in a processing kier (e.g., a large vat containing fibers, yarns, etc.). In such embodiments, the solutions containing cationic compounds may be applied as a coating to the fibers during the batch process, e.g., as an additional stage added at the end of the cleaning cycle. In such embodiments, the cleaned fibers may be coated directly in the processing kier following the fiber cleaning stage.
In some embodiments, the fibers may be treated in a fogging or spray tunnel, e.g., such that the solution containing cationic compound is applied to the fibers while they are on a moving conveyor belt. For example, the solution containing cationic compounds may be sprayed or fogged (e.g., a vapor containing the coating solutions may be present in an at least partially enclosed tunnel) onto the fiber in a pneumatic and/or a conveyor tunnel.
In some embodiments, the fibers may be treated in a hydroentangling water system during formation of a nonwoven material. Generally, the nonwoven formation platform called hydroentangling relies on high pressure water jets to entangle the fibers. In some embodiments, the solution containing cationic compound may be added to the recirculated water in the hydroentangling system and applied directly to the fibers as they are being hydroentangled.
In some embodiments, the fibers may be treated in an oiling chamber, such as commonly used in the woolen industry. For example, oils are commonly applied to fibers in an oiling chamber in order to lubricate those fibers prior to formation of a nonwoven fabric therefrom. Generally, it should be noted that treatment of the fibers in an oiling chamber can advantageously provide automatic and continuous distribution of the cationic compound on the fibers being processed. For example, the coating solutions may be homogenously distributed on the fibers by means of spray nozzles. In some embodiments, the quantity of the cationic compound solution can be adjusted, for example, according to different fiber blend compositions.
As noted above, the fibers may be formed into a fabric using wetlaid techniques. In such embodiments, the solution containing the cationic compound may be applied to the fibers in the mixing tanks of a wetlaid formation system. Generally, wetlaid formation uses short cut fibers dispersed in water (e.g., in a mixing tank) which then flows over a perforated screen to form the nonwoven substrate. Thus, the solution containing cationic compound may be added into the mixing tank prior to forming the nonwoven substrate therefrom.
In some embodiments, the fibers may be treated in a calendar or dip tray. In such embodiments, the fibers may be treated with the solution containing cationic compound after formation of a fabric or nonwoven material including those fibers. For example, in some embodiments, the fabric may travel through a calendar press in which a liquid coating is applied directly one or both surfaces of the nonwoven fabric. In some embodiments, the nonwoven fabric may travel through a dip tray containing the coating solution, e.g., such that the coating is applied directly to one or both surfaces of the nonwoven fabric. In either embodiments, the coated fabric can then be dried and rolled using conventional techniques commonly known in the art.
Generally, the noted treatment methods may be applied to the fibers directly or they may be applied to an already formed fiber-based product (e.g., such as a woven or non-woven fabric, a wipe or a cloth, a medical product, a wound care product, a linen, and the like) including a plurality of fibers therein. In one particular embodiment, for example, an already formed fabric roll may be treated with a solution containing a cationic compound to improve its compatibility with QAC. First, the fabric rolls can be unrolled using conventional methods and subjected to a coating process. For example, the untreated fabric is run through a coating tray containing a solution containing cationic compounds with a dwell time of, for example, between about 0.5 to about 5 seconds. Any solution containing a cationic compound as described herein above may be suitable for use as the coating solution. For example, the cationic coating solution may include alum, aluminum acetate, LEVOGEN, SUPERFLOC, and/or PDDA. In some embodiments, the solution concentration of the cationic compound (e.g., a cationic polymer such as PDDA) can be between about 0.05 wt % to about 10 wt % depending on the fabric properties and fabric liquid holdup after calendaring.
In some embodiments, the coated fabric may further be subjected to a calendaring step, e.g., in which the extra coating solution is removed by application of pressure and/or mechanical force. Typically, the amount of fabric liquid holdup after calendaring can be between about 50% to about 400% by weight of fiber, depending on the concentration of the coating solution and the fabric properties.
In some embodiments, the coated and calendared fabric may optionally be subjected to a drying step, e.g., in which the liquid holdup is decreased. Any type of drying mechanism typically used in the art may be suitable for drying the coated fabric. In some embodiments, the amount of fabric liquid holdup after drying can be between about 1% to about 15% by weight of fiber, depending to the fabric properties and particular type of drying unit used. In some embodiments, the coated, calendared, and dried fabric can be re-rolled.
In some embodiments, the fibers or fibers based products may be pre-treated with an alcohol prior to treatment with the solution containing cationic compound. Generally, the type of alcohol used for this pre-treatment may vary. In some embodiments, the alcohol pre-treatment may comprise treating the fibers or fiber-based product with ethanol or isopropyl alcohol, for example. It should be noted that pre-treatment with alcohol can provide an enhanced sanitizing effect and/or may increase the astringent properties of the fibers or fiber-based products. The concentration of the alcohol in the treatment solution is typically at least about 70% by weight, based on the total weight of the treatment solution.
In some embodiments, the fibers or fiber-based products may be pre-treated with a base. Generally, the type of bases used for this pre-treatment may vary. In some embodiments, the fibers or fiber-based products may be pre-treated with a base selected from the group consisting of sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and the like. In certain embodiments, the base is selected from carbonates (e.g., alkali metal carbonates like potassium carbonate or sodium carbonate), or bicarbonates including alkali metal bicarbonates such as sodium bicarbonate. It should be noted that pre-treatment with a base can, in certain embodiments, improve the coating efficacy (e.g., adhesion of the coating to the fibers) of the cationic compound solutions, as well as provide cleaning/scouring effect on the fibers. Further, it should be noted that pre-treatment with bases such as sodium carbonate, in particular, can improve the QAC compatibility of the fibers or fiber-based product in certain embodiments. An example concentration of base in a treatment solution is about 1% to about 50% by weight, based on the total weight of the treatment solution.
In some embodiments, the fibers or fiber-based products may optionally be post-treated with a polymer or resin. In some embodiments, the polymer or resin is derived from either petroleum or renewable sources, such as polyhydroxy alkanoates (e.g., PHB), aliphatic polyesters (e.g., polybutylene succidate) and co-polyesters, aromatic polyesters (e.g., polybutylene adipate terephthalate) and co-polyesters, polyester amides, polyamines and co-polymers of polyamines, polylactic acid, polyvinyl alcohol, poly e-caprolactone, thermoplastic starches, modified starches (including cationic starches), proteins, and chitosan. In some embodiments, the polymer or resin may be dispersed in a liquid, such as water prior to the post-treatment. In some embodiments, the polymer or resin is either thermoplastic or thermosetting. Such fiber post-treatment can, in certain embodiments, improve the durability of the cationic compound treatment, such as through improvement in the ability of the cationic compound treatment to withstand washing of the fiber or fabric. Note that certain polymer examples within the classes noted herein can be positively charged, and thus, could also be used as the cationic compound treatment. An example concentration of polymer or resin in a treatment solution is about 1% to about 50% by weight, based on the total weight of the treatment solution.
Following treatment of the fibers and/or fiber-based products with the cationic compound, a QAC solution may be applied to the treated fibers or fiber-based products in order to provide a sanitizing function. The QAC treatment of the fibers or fiber-based product (e.g., a fabric) can also occur simultaneously with the cationic compound treatment such as by, for example, combining the QAC solution with the solution containing the cationic compound prior to fiber/fabric treatment. Treatment of the fibers (or product made therefrom) with the QAC solution can occur at the same process stages set forth above with respect to cationic compound treatment.
Generally, for purposes of adding sanitizing function, the QAC solution can be applied to the treated fibers in various amounts and/or concentrations. For example, the QAC solution may comprise about 500 ppm to about 3000 ppm (e.g., about 1000 ppm to about 2600 ppm) of a quaternary ammonium compound, e.g., such as any of the quaternary ammonium compounds described herein above.
The fibrous materials treated with cationic compound as described herein can be characterized as having improved QAC compatibility, which can be measured as set forth in Example 1 and generally described in Slopek, et al., Adsorption of alkyl-dimethyl-benzyl-ammonium chloride on differently pretreated non-woven cotton substrates, Textile Research Journal 81 (15) 1617-1624 (2011), which is incorporated by reference herein. This laboratory test for QAC compatibility involves comparing the UV spectrum of a benzalkonium chloride solution following immersion of the fibrous material and comparing this UV spectrum to the UV spectrum of a standard solution. Using this comparison, changes in QAC concentration in the solution following fibrous material immersion can be determined and expressed as a % of quaternary ammonium compound retention in the solution. In certain embodiments of the present disclosure, treated fibrous materials can be characterized as providing at least about 40% quaternary ammonium compound retention in a benzalkonium chloride solution following immersion of the fibrous material in the benzalkonium chloride solution at a concentration of 1000 ppm for 5 minutes at room temperature, as determined by ultraviolet spectra of the benzalkonium chloride solution. In certain embodiments, the QAC retention following the test described above is at least about 50% or at least about 60% or at least about 70% or at least about 80% or at least about 90%.
It should be noted that any treatment method discussed herein can be used independently of each other, or in any combinations thereof. For example, a single treatment method as described herein may be used or multiple treatment methods may be used in combination (e.g., the fibers or fiber-based products and the QAC solution may both be pre-treated with a solution containing cationic compounds prior to contact with each other). In some embodiments, one or more additional pre-treatments as discussed above may be incorporated independently, in or more combinations. Generally, any treatment or pre-treatment method may be applied to the fibers prior to forming a fabric therefrom, during formation of the fabric, and/or after formation of the fabric.
The various treatment steps set forth herein can be performed at atmospheric pressure or elevated pressure up to about 3 bars unless otherwise indicated herein. In addition, the various treatment steps set forth herein are typically performed at a temperature of between about room temperature (e.g., 25° C.) and about 130° C.
As noted above, the various treatment methods provided herein (e.g., treatment of fibers/fiber-based products prior to application of a QAC solution or treatment of QAC solutions prior to application thereof to fibers/fiber-based products), and combinations thereof, will render cellulosic fibers to be substantially compatible with a QAC treatment in certain embodiments. Such QAC treatment provides a sanitizing function to the fibers and products so treated, and may provide enhanced utility when the product is a wipe or wiping cloth, for example. Such products may be used to cleanse or sanitize any surface that is contacted by such a wipe. This is also a non-limiting example of the utility and usefulness of fibers and fiber-based products that are treated in accordance with this invention.
The properties and functionalities imparted to fibers and fiber-based products treated according to the instant invention are durable to rinsing with water and to detergent washing following said treatment in certain embodiments. Further, fibers and/or fiber-based products treated using any of the methods discussed herein may be characterized as being reusable and/or may retain various functionalities (e.g., such as QAC retention and/or sanitizing function) after being rinsed, in certain embodiments.
The invention anticipates that, in certain embodiments, a cellulosic or protein fiber so treated may exhibit astringent properties when used in a personal cleansing wipe such as for the face, or in a medical product for the purpose of aiding the stop of blood flow from a wound, such as a dressing, sponge, wipe or wound cover. These are examples only and are not considered to be limiting to the utility of the invention relative to this functionality.
Fibers and/or fiber-based products treated with certain cationic compounds, such as alum, aluminum acetate, and/or PDDA, may derive some level of flame resistance from such treatments in certain embodiments. In this mode, products so treated, or made utilizing fibers so treated, may demonstrate an enhanced resistance to ignition when impinged by a flame source.
Fibrous Materials
The types of fibers suitable for use with any of the treatments and/or methods described herein may be natural or synthetic cellulosic, natural or synthetic protein fibers, or a combination thereof. Examples of suitable natural or synthetic cellulosic fibers include, but are not limited to, viscose, acetate, rayon, lyocell, cotton and bast fibers such as hemp, flax, ramie, jute, bamboo, nettle, kenaf, and Spanish broom. In some embodiments, the natural or synthetic cellulosic fibers can be lignocellulosic fibers, e.g., such as fibers having a lignin concentration of about 0.0001% to about 50% by weight. Examples of suitable natural or synthetic protein fibers include, but are not limited to, animal hair, wool, fur, silk, and the like.
In some embodiments, the fibers may be in the form of a plurality of fibers. In some embodiments, the plurality of fibers can comprise a blend of two or more fiber types. For example, in some embodiments, the fiber blend can include about 5% to about 100% by weight of the natural or synthetic cellulosic fibers. In some embodiments, the fiber blend may comprise at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% by weight of the natural or synthetic cellulosic fibers. In some embodiments, the fiber blend may comprise up to about 95% by weight non-cellulosic natural or synthetic fibers. For example, in some embodiments, the fiber blend may comprise up to 10%, up to 20%, up to 30%, up at 40%, up to 50%, up to 60%, up to 70%, up to 80%, or up to 90% by weight non-cellulosic natural or synthetic fibers.
In some embodiments, the natural or synthetic cellulosic fibers may comprise at least about 5% bast fiber by weight. In some embodiments, the natural or synthetic cellulosic fiber may comprise at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% bast fiber by weight.
In some embodiments, bast fibers utilized in this disclosure can be individualized via mechanical or chemical cleaning to, for example, remove surface impurities. In some embodiments, the mechanically or chemically cleaned fibers may have a staple length of about 1 mm to about 100 mm. Mechanical cleaning of bast fibers occurs during a process called skutching or decortication. During this process the plant stems are broken and combed to remove non-fiber components such as hemicellulose, pectin, lignin, and general debris. For example, the bale of bast fiber may be unrolled in to the machine and then breaker rolls may split the stems and expose the fiber bundles. Further, rotating combs may be used to clean the fiber of all trash and non-fiber material such that the fibers are then discharged to a separate collection area. Decortication is a similar process that utilizes pinned cylinders in place of rotating combs. Mechanical cleaning individualizes the bast fibers and removes less pectin than chemically cleaning. Chemical cleaning can occur, for example, in keirs.
Mechanically cleaned fibers have had a portion of the pectin removed from the fiber and are considered by this application to be pectin reduced. The residual level of pectin/contaminants vary from geographic region and growing season and depends on the natural retting of the fiber and the number of rotating combs/pinned rollers that the fiber is subjected to. Mechanically cleaning bast fibers is commonplace and grades of pectin-reduced fiber are known to those skilled in the art.
Chemical cleaning of bast fibers occurs in several ways: water retting, chemical cleaning, or enzymatic cleaning. Processes for chemically cleaning the bast fibers may, in some embodiments, be referred to as being chemically scoured to remove pectin, lignin, and other non-cellulosic materials. Natural chemical cleaning, called water retting, occurs in pools or streams whereby the bast fiber stalks are placed in the water for a period of several days to a week or more. Natural microbes remove the pectin from the fiber releasing the hemicellulose from the fiber resulting in clean, pectin reduced, individualized bast fiber. Chemical cleaning is a faster process and is performed on mechanically cleaned bast fibers and in an industrial facility possessing equipment capable of working at greater than atmospheric pressure and with temperatures ranging from 80° C. to over 130° C. The bast fiber is subjected to heat, pressure, and caustic soda or other cleaning agents to quickly remove pectin and lignin. Enzymatic cleaning is very similar to chemical cleaning with a portion of the caustic soda and other chemical agents being replaced by enzymes such as pectinase or protease. Once cleaned, the bast fibers are optionally de-watered via centrifuge and/or air dryers to a pre-set moisture content of, for example, about 2% to about 20% by weight. In embodiments where the cleaned bast fibers are not de-watered, they may be provided in the form of a saturated solution and may optionally be dried to the desired moisture content prior to optional crimping of the fibers.
Chemically cleaned bast fibers are considered by the industry to be substantially free of pectin. US2014/0066872 to Baer et al., which is incorporated by reference herein, describes fiber with substantially reduced pectin as having less than 10%-20% by weight of the pectin content of the naturally occurring fibers from which the substantially pectin-free fibers are derived.
When the cellulosic fibers or cellulosic fiber-based products of the invention include or are based on bast fibers, the inventors have determined that imposing crimp on those naturally straight fibers can be important to desirable aesthetic and performance features in the products produced from those fibers, in certain embodiments. Therefore, bast fibers of the instant invention advantageously have an imposed level of crimp of at least about 1 crimp per centimeter. In some embodiments, the crimped bast fibers may comprise between about 1 to about 10 crimps per centimeter. Various means for imposing a crimp therein may be suitable, for example the means for imposing crimp may be mechanical or chemical in nature. For example, the crimping method may include contacting fiber mat of bast fibers with a pair of heated crimping rolls to provide crimped bast fibers having a crimp of, for example, about 1 to about 10 crimps per centimeter, the pair of heated crimping rolls comprising a first crimping roll being positioned proximate to the top side of the fiber mat and opposing a second crimping roll positioned proximate to the bottom side of the fiber mat.
In certain embodiments, it is advantageous for the fibrous material utilized in the present disclosure to be substantially free of anionic surface treatment, such as by carboxymethylation or treatment with carboxymethycellulose (CMC). For example, certain embodiments of fibrous material of the disclosure can be characterized as having less than 0.20 mol/kg of dry fiber of anionic moieties (e.g., less than 0.15 mol/kg of dry fiber or less than 0.10 mol/kg of dry fiber). Certain embodiments of the disclosure can be characterized as substantially free of CMC, such as less than about 0.5% by dry weight of CMC or less than about 0.1% by dry weight of CMC or 0.0% by dry weight of CMC. In certain embodiments, the fibrous material utilized in the present disclosure can also be characterized as being substantially free (see, e.g., levels noted above) or completely free of exogenous CMC, meaning CMC intentionally added to the fibrous material. In certain embodiments, these limitations on CMC inclusion or presence applies to both the fibrous material used as a starting material and the treated fibrous material following any of the treatments noted herein. Determination of anionic moiety and CMC concentration is described, for example, in US2019/0257029 to Kuehn et al., which is incorporated by reference herein.
In some embodiments, the fibers of the invention may be treated in fiber form or as fibers incorporated into a fiber-based product, as noted above. In some embodiments, such fibers may be useful as treated fibers in bulk form, such as a bale, bundle, mat, batt, web, boll, ball, or tuft. Example fiber-based products may include fabrics, composites of fabrics, bulk fiber components, or other composites with bulk fiber components. Examples of the latter might be a swab or a styptic pencil. In some embodiments, the fiber-based product may include woven fabrics, knitted or nonwoven fabrics, or composites of two or more of said fabrics. In some embodiments, the fiber-based product may be in the form of a composite of two or more components, for example, wherein each component may be in the form of a plurality of fibers or a fabric, or a combination thereof.
Among the types of useful products, the desirable performance features of which are linked to the cationic compound solution treatment are, not exclusively, wipes, wiping cloths, garments, components of garments, textile-based household products, linens, bandages, wound care and surgical sponges and wipes and wound closure products.
The foregoing is considered to provide examples of the principles of the invention. The scope of modifications as may be made to the invention are not limited beyond that imposed by the prior art and as set forth in the claims herein.
Generally, the following examples describe testing of various cellulosic fibers (e.g., such as hemp and flax fibers) that have been treated using various treatments and/or methods as described herein. The terms “QAC” and “Quat” as referred to in the examples and in the Figures, are meant to be interchangeable and generally refer to the quaternary ammonium compound utilized in the examples.
Testing was conducted to determine the QAC retention of treated and untreated fibers (flax and hemp). First, the flax and hemp fibers were pre-treated with sodium carbonate, using 5% wof solution of sodium carbonate, for 1 hour at 90° C. This pre-treatment was applied to all tested fibers. Then, certain samples of the pre-treated fibers were treated with aluminum acetate, using a 20% wof solution of aluminum acetate, for 1 hour at 50° C. Excess solution was then removed and the fibers were rinsed under cold tap water for 1 minute. The fibers were then dried. A 1 gram fiber sample of both treated and untreated flax and hemp fibers was immersed in 10 ml of 2600 ppm QAC solution (benzalkonium chloride) and let to stand in the QAC solution in a sealed vial. The fiber sample was removed from the QAC solution after 2 weeks.
The concentration of QAC in the bulk solution was determined by comparing the ultraviolet (UV) spectra of the solution at the end of each experimental run with that of a standard solution using an ultraviolet-visible (UV-vis) spectrophotometer, as generally described in Slopek, et al., Adsorption of alkyl-dimethyl-benzyl-ammonium chloride on differently pretreated non-woven cotton substrates, Textile Research Journal 81 (15) 1617-1624 (2011). The testing was conducted using a Cary 50 UV-Vis spectrophotometer available from Varian Inc., USA. Standard QAC solutions were created and used to develop calibration curves that relate QAC concentration to the absorbance at 263 nm. Each experimental sample solution following fiber treatment was then compared the absorbance at 263 nm with the calibration curve to get the QAC concentration. Each fiber sample following QAC immersion was squeezed by hand to remove entrained QAC solution as needed to ensure a QAC solution testing sample of at least 5 mL. All testing was conducted at room temperature (25° C.).
The percentage of QAC exhausted from the bulk solution, and thus absorbed onto the tested fibers, can be calculated by Equation (1) below:
where % E is the percentage exhaustion of QAC, Ao is the absorbance of the QAC solution at the beginning (before fiber immersion) and At is the absorbance of the QAC solution after fiber immersion. Subtracting the % E from 100 provides the percentage of QAC remaining in the solution, which is referred to as “Remaining Quat” herein.
Testing was conducted to determine the effect of pre-treating hemp and flax fibers with sodium carbonate prior to treatment with aluminum acetate. Fibers (flax and hemp) were pre-treated with sodium carbonate (soda ash) before treatment with aluminum acetate. Pre-treatment was conducted using 5% wof sodium carbonate solution for 1 hour at 90° C. The excess solution was removed and the fibers were rinsed under cold tap water for 10 minutes. Treatment with aluminum acetate solution was accomplished with the same procedure as set forth in Example 1. QAC compatibility was investigated following the same procedure as Example 1 using a QAC concentration of 1000 ppm and 5 minutes of contact time.
Testing was conducted to analyze the effect of the QAC concentration on QAC retention in untreated fibers, treated fibers, and commercially available synthetic fibers. Flax fibers were treated with the same procedure as set forth in Example 1. QAC compatibility was investigated following the same procedure as set forth in Example 1 using different QAC concentrations of 500 ppm, 1000 ppm, and 2600 ppm with a contact time of 5 minutes.
Testing was conducted to determine the QAC retention after different QAC contact periods for treated flax fibers as compared to a commercially available synthetic fiber. Flax fibers were treated with the same procedure as set forth in Example 1. QAC compatibility was investigated following the same procedure as set forth in Example 1 with QAC concentration of 1000 ppm for 1, 5, 10, 30, 60, 120, and 180 minutes solution standing time.
Testing was conducted to determine the effect of the aluminum acetate concentration on the QAC retention in flax fibers treated therewith. Flax fibers were treated with different concentrations of aluminum acetate solution (1, 5, 10, 20, and 40% wof) with the same procedure as set forth in Example 1. QAC compatibility was investigated following the same procedure as set forth in Example 1 for QAC concentration of 1000 ppm and 5 minutes contact time.
Testing was conducted to determine the effectiveness of different QAC solutions on both treated and untreated fibers. Flax fiber was treated with a 5% wof aluminum acetate solution following the same procedure as set forth in Example 1. QAC compatibility of both untreated and the treated flax fiber in three different QAC solutions was investigated: pure 1000 ppm QAC solution (benzalkonium chloride), 3% by weight PDDA in 1000 ppm QAC solution, and 2% by weight aluminum potassium sulfate in 1000 ppm QAC solution (weight percentages based on total weight of solution). QAC compatibility was investigated using the same procedure as set forth in Example 1 using 5 minutes contact time.
Testing was conducted to determine the effectiveness of different treatments on flax fiber. Flax fiber was treated using aluminum sulfate, aluminum potassium sulfate, aluminum acetate, and PDDA using the same procedure as set forth in Example 1. QAC compatibility was investigated using the same procedure as set forth in Example 1 for QAC concentration of 1000 ppm and 5 minutes contact time.
Testing was conducted to determine the effectiveness of different treatments on a fabric of 85% Flax and 15% TENCEL™ lyocell fibers. The fabric was treated using PDDA, and LEVOGEN cationic polymer available from Kemira Oyj using the same procedure as set forth in Example 1 using 3 wt % solution concentration. The treatment was done at 25° C. for 1 hour. QAC compatibility was investigated using the same procedure as set forth in Example 1 for QAC concentration of 400 ppm and 5 minutes contact time. QAC concentration in each test solution following fiber immersion was measured using Quat test strips (Hydrion QT-10) available from Micro Essential Laboratory Inc.
Testing was conducted to determine the effectiveness of different treatments on a cotton fabric. The fabric was treated using PDDA, and LEVOGEN cationic polymer available from Kemira Oyj using the same procedure as set forth in Example 1 using 3 wt % solution concentration. The treatment was done at 25° C. for 1 hour. QAC compatibility was investigated using the same procedure as set forth in Example 1 for QAC concentration of 400 ppm and 5 minutes contact time. QAC concentration in each test solution following fiber immersion was measured using Quat test strips (Hydrion QT-10) available from Micro Essential Laboratory Inc.
Testing was conducted to determine the effectiveness of different treatments on flax and hemp fiber samples. Flax and hemp were treated using LEVOGEN cationic polymer available from Kemira Oyj using the same procedure as set forth in Example 1 using 3 wt % solution concentration. The treatment was done at 25° C. for 1 hour. QAC compatibility was investigated using the same procedure as set forth in Example 1 for QAC concentration of 400 ppm and 5 minutes contact time. QAC concentration in each test solution following fiber immersion was measured using Quat test strips (Hydrion QT-10) available from Micro Essential Laboratory Inc.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2020/050643 | 5/12/2020 | WO | 00 |
