Patent Application
20170037564
The present disclosure relates to nonwoven fibrous structures and related media with ionic reinforcement material and methods of forming the same.
Nonwoven fibrous webs have been used to produce a variety of absorbent articles that are useful, for example, as absorbent wipes for surface cleaning, as wound dressings, as gas and liquid absorbent or filtration media, and as barrier materials for sound absorption.
Although some methods of forming nonwoven fibrous webs are known, the art continually seeks new methods of forming and/or bonding nonwoven webs, particularly air-laid nonwoven fibrous webs having particular characteristics with a relatively high cross direction (CD) tensile strength and a relatively high machine direction (MD) tensile strength.
Thus, in one aspect, the present disclosure relates to a method of making a nonwoven fibrous structure (e.g., a nonwoven fibrous web), including: introducing a plurality of fibers into a forming chamber, dispersing the fibers within the forming chamber to form a population of individual fibers suspended in a gas, collecting the population of fibers as a nonwoven fibrous structure on a collector, and bonding at least a portion of the population of fibers together with an ionic reinforcement material. In some exemplary embodiments, the method comprises applying an ionic liquid material to the population of fibers. In certain exemplary embodiments, the method includes bonding at least the portion of the population of fibers together comprises curing the applied ionic liquid material to form the ionic reinforcement material.
In some exemplary embodiments, the applied ionic liquid material further comprises water, and where curing removes at least a portion of the water from the applied ionic liquid material to cause bonding of the ionic reinforcement material between the population of fibers. In certain exemplary embodiments, the applied ionic liquid material further comprises at least one binder resin, optionally wherein the applied ionic liquid material acts as a plasticizer for the at least one binder resin. In some exemplary embodiments, the at least one binder resin is selected from the group consisting of a phenolic resin, a bio-based resin, a thermoplastic (meth)acrylic (co)polymer resin, an epoxy resin, or a combination thereof. In certain exemplary embodiments, the method includes bonding with a binder resin mixture and the ionic liquid material to provide a nonwoven fibrous structure with a tensile strength that is greater than a nonwoven fibrous structure bonded with the binder resin mixture in the absence of the ionic liquid material.
In some exemplary embodiments, the ionic liquid material comprises at least one cation and at least one anion. In certain exemplary embodiments, the at least one cation is selected from the group consisting of nitrogen containing heterocyclic cations, ammonium, phosphonium, or sulfonium; and further wherein the at least one anion is selected from the group consisting of halogen anions, fluorine containing anions, alkyl sulfate anions, alkyl phosphate anions, acetate, dicyanamide (N(CN)2), or thiocyanate (SCN). In some exemplary embodiments, the method includes spraying the ionic liquid material, roll coating the ionic liquid material, dip coating the ionic liquid material, or a combination thereof. In certain exemplary embodiments, the ionic liquid material is an ionic liquid solution in a solvent, optionally wherein the solvent is aqueous.
In some exemplary embodiments, bonding at least the portion of the population of fibers together includes applying a thermosetting binder to the population fibers. In certain exemplary embodiments, bonding at least the portion of the population of fibers includes heating the portion of the population of fibers. In some exemplary embodiments, the ionic reinforcement material provides at least one distinguishing characteristic to the nonwoven fibrous structure selected from the group consisting of a fire retardant characteristic, an antistatic characteristic, an antibacterial characteristic, an antimicrobial characteristic, an antifungal characteristic, or a combination thereof. In certain exemplary embodiments, the population of fibers includes fibers selected from the group consisting of staple fibers, melt blown fibers, natural fibers, bio-based fibers, or a combination thereof.
In certain exemplary embodiments, the nonwoven fibrous structure includes a population of particulates bonded to the nonwoven fibrous structure, further wherein the particulates are selected from the group consisting of abrasive particulates, detergent particulates, anti-bacterial particulates, adsorbent particulates, absorbent particulates, or a combination thereof. In some exemplary embodiments, the nonwoven fibrous structure is a structure selected from the group consisting of a mat, a web, a sheet, a scrim, or a combination thereof.
The disclosure also relates to a nonwoven fibrous web prepared according to the method described herein. In addition, the disclosure relates to a nonwoven fibrous structure comprising a population of randomly oriented fibers bonded together at a plurality of intersection points with an ionic reinforcement material. In some exemplary embodiments, the ionic reinforcement material is comprised of an ionic plasticizer (e.g., ionic liquid acting as a plasticizer). In certain exemplary embodiments, the ionic reinforcement material is comprised of an ionic liquid and a binder selected from the group consisting of a (meth)acrylic (co)polymer binder, a styrene-butadiene latex binder, a bio-based binder, or a combination thereof. In some exemplary embodiments, the nonwoven fibrous structure comprises from 1 to 40 wt. % of the ionic liquid. In further embodiments, the ionic liquid comprises water, one or more cations, and one or more anions.
In some exemplary embodiments, the nonwoven fibrous structure exhibits at least one distinguishing characteristic selected from the group consisting of a fire retardant characteristic, an antistatic characteristic, an antibacterial characteristic, an antimicrobial characteristic, an antifungal characteristic, or a combination thereof. In certain exemplary embodiments, the ionic reinforcement material provides the at least one distinguishing characteristic. In some exemplary embodiments, the ionic reinforcement material provides at least two of the distinguishing characteristics. In certain exemplary embodiments, the population of fibers includes thermoplastic (co)polymer fibers further comprising a (co)polymer selected from poly(propylene), poly(ethylene), poly(butane), poly(ethylene) terephthalate, poly(butylene) terephthalate, poly(ethylene) napthalate, poly(amide), poly(urethane), poly(lactic acid), poly(vinyl)alcohol, poly(phenylene) sulfide, poly(sulfone), liquid crystalline polymer, poly(ethylene)-co-poly(vinyl)acetate, poly(acrylonitrile), cyclic poly(olefin), poly(oxymethylene), poly(olefinic) thermoplastic elastomers, recycled fibers containing any of the preceding thermoplastic (co)polymers, or a combination thereof.
In some exemplary embodiments, the population of fibers includes natural fibers selected from cotton, wool, jute, agave, sisal, coconut, soybean, hemp, viscose, bamboo, or a combination thereof. In certain exemplary embodiments, the nonwoven fibrous structure includes a population of particulates bonded to the nonwoven fibrous structure, further wherein the particulates are selected from the group consisting of abrasive particulates, detergent particulates, anti-bacterial particulates, adsorbent particulates, absorbent particulates; or a combination thereof. In some exemplary embodiments, the population of particulates exhibits a median particle diameter of from 0.1 micrometer to 1,000 micrometers. In certain exemplary embodiments, the population of fibers exhibits a median fiber diameter of from 1 micrometer to 50 micrometers. In some exemplary embodiments, the nonwoven fibrous structure is a structure selected from the group consisting of a mat, a web, a sheet, a scrim, or a combination thereof.
Various exemplary embodiments of the present disclosure are further illustrated by the following listing of exemplary embodiments, which should not be construed to unduly limit the present disclosure:
Various aspects and advantages of embodiments of the presently disclosed invention have been summarized. The above Summary is not intended to describe each illustrated embodiment or every implementation of the presently disclosed invention. The Drawings and the Detailed Description that follow more particularly exemplify certain preferred embodiments using the principles disclosed herein.
Exemplary embodiments of the present disclosure are further described with reference to the appended figures, wherein:
As used in this specification and the appended embodiments, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to fine fibers containing “a compound” includes a mixture of two or more compounds. As used in this specification and the appended embodiments, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
As used in this specification, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.8, 4, and 5).
Unless otherwise indicated, all numbers expressing quantities or ingredients, measurement of properties and so forth used in the specification and embodiments are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached listing of embodiments can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claimed embodiments, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
For the following Glossary of defined terms, these definitions shall be applied for the entire application, unless a different definition is provided in the claims or elsewhere in the specification.
“Nonwoven fibrous web” or “nonwoven fibrous structure” means an article or sheet having a structure of individual fibers or fibers, which are interlaid, but not in an identifiable manner as in a knitted fabric. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, air-laying processes, and bonded carded web processes.
“Die” means a processing assembly for use in polymer melt processing and fiber extrusion processes, including but not limited to meltblowing and spun-bonding.
“Meltblowing” and “meltblown process” means a method for forming a nonwoven fibrous web by extruding a molten fiber-forming material through a plurality of orifices in a die to form fibers while contacting the fibers with air or other attenuating fluid to attenuate the fibers into fibers, and thereafter collecting the attenuated fibers. An exemplary meltblowing process is taught in, for example, U.S. Pat. No. 6,607,624 (Berrigan et al.).
“Meltblown fibers” means fibers prepared by a meltblowing or meltblown process.
“Spun-bonding” and “spun bond process” mean a method for forming a nonwoven fibrous structure by extruding molten fiber-forming material as continuous or semi-continuous fibers from a plurality of fine capillaries of a spinneret, and thereafter collecting the attenuated fibers. An exemplary spun-bonding process is disclosed in, for example, U.S. Pat. No. 3,802,817 to Matsuki et al.
“Spun bond fibers” and “spun-bonded fibers” mean fibers made using spun-bonding or a spun bond process. Such fibers are generally continuous fibers and are entangled or point bonded sufficiently to form a cohesive nonwoven fibrous web such that it is usually not possible to remove one complete spun bond fiber from a mass of such fibers. The fibers may also have shapes such as those described, for example, in U.S. Pat. No. 5,277,976 to Hogle et al., which describes fibers with unconventional shapes.
“Carding” and “carding process” mean a method of forming a nonwoven fibrous web webs by processing staple fibers through a combing or carding unit, which separates or breaks apart and aligns the staple fibers in the machine direction to form a generally machine direction oriented fibrous nonwoven web. An exemplary carding process is taught in, for example, U.S. Pat. No. 5,114,787 to Chaplin et al.
“Bonded carded web” refers to nonwoven fibrous web formed by a carding process wherein at least a portion of the fibers are bonded together by methods that include for example, thermal point bonding, autogenous bonding, hot air bonding, ultrasonic bonding, needle punching, calendering, application of a spray adhesive, and the like.
“Calendering” means a process of passing a nonwoven fibrous web through rollers with application of pressure to obtain a compressed and bonded fibrous nonwoven web. The rollers may optionally be heated.
“Densification” means a process whereby fibers which have been deposited either directly or indirectly onto a filter winding arbor or mandrel are compressed, either before or after the deposition, and made to form an area, generally or locally, of lower porosity, whether by design or as an artifact of some process of handling the forming or formed filter. Densification also includes the process of calendering webs.
“Non-hollow” with particular reference to projections extending from a major surface of a nonwoven fibrous structure means that the projections do not contain an internal cavity or void region other than the microscopic voids (i.e. void volume) between randomly oriented discrete fibers.
“Randomly oriented” with particular reference to a population of fibers means that the fiber bodies are not substantially aligned in a single direction.
“Air-laying” is a process by which a nonwoven fibrous web layer can be formed. In the air-laying process, bundles of small fibers having typical lengths ranging from about 3 to about 52 millimeters (mm) are separated and entrained in an air supply and then deposited onto a forming screen, usually with the assistance of a vacuum supply. The randomly oriented fibers may then be bonded to one another using, for example, thermal point bonding, autogenous bonding, hot air bonding, needle punching, calendering, a spray adhesive, and the like. An exemplary air-laying process is taught in, for example, U.S. Pat. No. 4,640,810 to Laursen et al.
“Particulate loading” or a “particle loading process” means a process in which particulates are added to a fiber stream or web while it is forming. Exemplary particulate loading processes are taught in, for example, U.S. Pat. No. 4,818,464 to Lau and U.S. Pat. No. 4,100,324 to Anderson et al.
“Particulate” and “particle” are used substantially interchangeably. Generally, a particulate or particle means a small distinct piece or individual part of a material in finely divided form. However, a particulate may also include a collection of individual particles associated or clustered together in finely divided form. Thus, individual particulates used in certain exemplary embodiments of the present disclosure may clump, physically intermesh, electro-statically associate, or otherwise associate to form particulates. In certain instances, particulates in the form of agglomerates of individual particulates may be intentionally formed such as those described in U.S. Pat. No. 5,332,426 (Tang et al.).
“Layer” means a single stratum formed between two major surfaces. A layer may exist internally within a single web, e.g., a single stratum formed with multiple strata in a single web having first and second major surfaces defining the thickness of the web. A layer may also exist in a composite article comprising multiple webs, e.g., a single stratum in a first web having first and second major surfaces defining the thickness of the web, when that web is overlaid or underlaid by a second web having first and second major surfaces defining the thickness of the second web, in which case each of the first and second webs forms at least one layer. In addition, layers may simultaneously exist within a single web and between that web and one or more other webs, each web forming a layer.
“Particulate density gradient,” “sorbent density gradient,” and “fiber population density gradient” mean that the amount of particulate, sorbent or fibrous material within a particular fiber population (e.g., the number, weight or volume of a given material per unit volume over a defined area of the web) need not be uniform throughout the nonwoven fibrous web, and that it can vary to provide more material in certain areas of the web and less in other areas.
Various exemplary embodiments of the disclosure will now be described with particular reference to the Drawings. Exemplary embodiments of the invention may take on various modifications and alterations without departing from the spirit and scope of the disclosure. Accordingly, it is to be understood that the embodiments of the invention are not to be limited to the following described exemplary embodiments, but is to be controlled by the limitations set forth in the claims and any equivalents thereof.
Nonwoven fibrous structures (e.g., nonwoven fibrous webs, etc.) have a plurality of applications (e.g., uses) including: cleaning applications, filtration applications, and/or textile applications, among others. Nonwoven fibrous structures can be better suited to particular applications when the nonwoven fibrous structure exhibits particular characteristics (e.g., fire retardant characteristics, antistatic characteristics, antibacterial characteristics, antimicrobial characteristics, antifungal characteristics, etc.). The present disclosure describes nonwoven fibrous structures that include a portion of a population of fibers that are bonded together with an ionic reinforcement material and methods of making the same. The ionic reinforcement material provides an increase in the tensile strength of the nonwoven fibrous structure as well as provides a number of characteristics. In some exemplary embodiments, the ionic reinforcement material provides a plurality of characteristics as described herein.
As described further herein, the ionic reinforcement material can be applied to the nonwoven fibrous structure utilizing an application of an ionic liquid material. The ionic liquid material can include an ionic liquid (e.g., liquid comprising at least one cation and at least one anion). The ionic liquid material applied to the nonwoven fibrous structure can be cured to bind a portion of the population of fibers of the nonwoven fibrous structure with an ionic reinforcement material.
In some optional embodiments, the present disclosure describes a nonwoven fibrous structure comprising a plurality of randomly oriented fibers 2, the nonwoven fibrous structure further comprising a plurality of optional non-hollow projections 200 extending from a major surface 204 of the nonwoven fibrous structure (as considered without the projections), and a plurality of substantially planar land areas 202 formed between each adjoining projection 200 in a plane defined by and substantially parallel with the major surface 204.
In some exemplary embodiments, the randomly oriented discrete fibers 2 can include fibers 120 selected from the group consisting of mono-component fibers, multi-component fibers, crimped fibers, or a combination thereof. In certain exemplary embodiments, the randomly oriented discrete fibers 2 can include fibers selected from the group consisting of staple fibers, melt blown fibers, natural fibers, or a combination thereof. In some exemplary embodiments, the randomly oriented discrete fibers 2 can include natural fibers selected from cotton, wool, jute, agave, sisal, coconut, soybean, hemp, viscose, bamboo, or a combination thereof. In certain exemplary embodiments, the randomly oriented discrete fibers 2 can include fibers that exhibit a median fiber diameter of from 1 micrometer to 50 micrometers.
In some exemplary embodiments, the randomly oriented discrete fibers 2 can include thermoplastic (co)polymer fibers further comprising a (co)polymer selected from poly(propylene), poly(ethylene), poly(butane), poly(ethylene) terephthalate, poly(butylene) terephthalate, poly(ethylene) napthalate, poly(amide), poly(urethane), poly(lactic acid), poly(vinyl)alcohol, poly(phenylene) sulfide, poly(sulfone), liquid crystalline polymer, poly(ethylene)-co-poly(vinyl)acetate, poly(acrylonitrile), cyclic poly(olefin), poly(oxymethylene), poly(olefinic) thermoplastic elastomers, recycled fibers containing any of the preceding thermoplastic (co)polymers, or a combination thereof.
The randomly oriented discrete fibers 2 may, in some exemplary embodiments, optionally include filling fibers 110. The filling fibers 110 are any fiber other than a multi-component fiber. The optional filling fibers 110 are preferably mono-component fibers, which may be thermoplastic or “melty” fibers. In certain exemplary embodiments, the filling fibers can include bio-based fibers. Bio-based fibers can include natural fibers and/or biodegradable fibers. For example, the optional filling fibers 110 may, in some exemplary embodiments, comprise natural fibers, more preferably natural fibers derived from renewable sources, and/or incorporating recycled materials. Non-limiting examples of suitable natural fibers include those of bamboo, cotton, wool, jute, agave, sisal, coconut, sawgrass, soybean, hemp, and the like. Cellulosic fibers (e.g., cellulose, cellulose acetate, cellulose triacetate, rayon, and the like) may be particularly well-suited natural fibers. The fiber component used may be virgin fibers or recycled waste fibers, for example, recycled fibers reclaimed from garment cuttings, carpet manufacturing, fiber manufacturing, textile processing, paper, reclaimed wood, or the like. In another example, the optional filling fibers 110 are biodegradable fibers. The biodegradable fibers can include, but are not limited to fibers comprising a substantial amount of aliphatic polyester (co)polymer derived from poly(lactic acid), poly (glycolic acid), poly (lactic-co-glycolic acid) blends, and/or a combination thereof. In some presently preferred embodiments, at least some of the filling fibers 120 may be bonded to at least a portion of the discrete fibers 2 at a plurality of intersection points with the first region 112 of the multi-component fibers 110.
In some exemplary embodiments of the previously described nonwoven fibrous structure, the nonwoven fibrous structure 234 may optionally include a plurality of particulates 130 as shown in
In some exemplary embodiments, the optional particulates 130 can be particulates selected from the group consisting of abrasive particulates, detergent particulates, anti-bacterial particulates, adsorbent particulates, absorbent particulates, or a combination thereof. In certain exemplary embodiments, the optional population of particulates 130 can exhibit a median particle diameter of from 0.1 micrometer to 1,000 micrometers. The optional particulates 130 can be applied at various stages of the forming process for the nonwoven fibrous structure 234. In one example, the optional particulates can be applied by a particulate loading process. Exemplary particulate loading processes are taught in, for example, U.S. Pat. Nos. 4,818,464 and 4,100,324.
Additionally, in some particular exemplary embodiments, an input stream may advantageously be located to introduce particulates 130 in a manner such that the particulates 130 are distributed substantially uniformly throughout the nonwoven fibrous structure 234. Alternatively, in some particular exemplary embodiments, an input stream may advantageously be located to introduce particulates 130 in a manner such that the particulates 130 are distributed substantially at a major surface of the nonwoven fibrous structure 234, for example, proximate a lower major surface of nonwoven fibrous structure 234, or proximate the upper major surface of the nonwoven fibrous structure 234.
In certain exemplary embodiments, a binder can be applied to the nonwoven fibrous structure 234 and may provide further strength to the nonwoven fibrous structure 234, may further secure the particulates 130 to the fibers of the nonwoven fibrous structure 234, and/or may provide additional stiffness for an abrasive or scouring article. The binder coating may be applied by known processing means such as roll coating, spray coating, and immersion coating and combinations of these coating techniques. The binder coating may include additional particulates 130 within the binder or additional particulates 130 may be incorporated and secured to the binder.
In exemplary embodiments, an ionic liquid material (e.g., ionic liquid mixture) can be coated on the nonwoven fibrous structure 234. The ionic liquid material can include an ionic liquid (e.g., liquid that comprises at least one cation and at least one anion, aqueous solution that comprises at least one cation and at least one anion). That is, the ionic liquid material is an ionic liquid solution in a solvent, optionally the solvent is aqueous. In some exemplary embodiments, the ionic liquid can include at least one cation that is selected from the group containing heterocyclic cations, ammonium, phosphonium, or sulfonium. In addition, in certain exemplary embodiments, the ionic liquid can include at least one anion that is selected from the group consisting of halogen anions, fluorine containing anions, alkyl sulfate anions, alkyl phosphate anions, acetate, dicyanamide (N(CN)2), or thiocyanate (SCN). The ionic liquid can be comprised of a salt dissolved in a liquid. For example, the ionic liquid material can comprise a salt dissolved in water to produce an ionic liquid that comprises at least one cation and at least one anion in an aqueous solution. For example, the ionic liquid material can comprise a salt dissolved in water to produce an ionic liquid that comprises at least one cation and at least one anion in an aqueous solution. In some exemplary embodiments, the ionic liquid can include at least one of the ionic liquids from the group of: sodium chloride (NaCl), choline dihydrogen phosphate, 1-ethyl-3-methylimidazolium ethyl phosphate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium triflate, or 1-ethyl-3-methylimidazolium dicyanamide.
The ionic liquid material may be applied by known processing means such as roll coating, spray coating, and immersion coating and combinations of these coating techniques. In some exemplary embodiments, the ionic liquid material is introduced as a mist from an atomizer within a forming chamber. In certain exemplary embodiments, the ionic liquid material wets the fibers so that particulates cling to the surface of the fibers.
In some exemplary embodiments, the ionic liquid material can also include a binder. The binder may comprise a resin. Suitable resins include phenolic resins, a bio-based resin, a thermoplastic (meth)acrylic (co)polymer resin, an epoxy resin, polyurethane resins, polyureas, styrene-butadiene rubbers, nitrile rubbers, epoxies, acrylics, and polyisoprene. The binder may be water soluble. Examples of water soluble binders include surfactants, polyethylene glycol, polyvinylpyrrolidones, polylactic acid (PLA), polyvinylpyrrolidone/vinyl acetate copolymers, polyvinyl alcohols, carboxymethyl celluloses, hydroxypropyl cellulose starches, polyethylene oxides, polyacrylamides, polyacrylic acids, cellulose ether polymers, polyethyl oxazolines, esters of polyethylene oxide, esters of polyethylene oxide and polypropylene oxide copolymers, urethanes of polyethylene oxide, and urethanes of polyethylene oxide and polypropylene oxide copolymers.
In embodiments where the ionic liquid material includes the binder, the ionic liquid material can include from 1 to 40 weight percent (wt. %) of an ionic liquid and a binder in a liquid mixture (e.g., liquid solution, aqueous solution, etc.). In certain exemplary embodiments, the ionic liquid material can include from 1 to 10 wt. % of an ionic liquid and a binder in a liquid mixture. That is, the ionic liquid material can include a particular weight percent of ionic liquid, a binder as described herein, and/or a percentage of water. Thus, the ionic liquid material can include the ionic liquid and the binder as a mixture and/or solution and applied by known processing means such as roll coating, spray coating, and immersion coating and combinations of these coating techniques.
In embodiments where the ionic liquid material includes the binder, the ionic liquid can act as a plasticizer for the binder in the ionic liquid material. That is, the ionic liquid can increase the elongation (e.g., plasticity, fluidity) of the resulting nonwoven fibrous structure 234. In some exemplary embodiments, an increase in elongation of the nonwoven fibrous structure 234 occurs in the machine direction (MD). In certain exemplary embodiments, the increase in elongation of the nonwoven fibrous structure 234 occurs in the transverse direction (TD). In some exemplary embodiments, the increase in elongation of the air laid nonwoven fibrous structure occurs in both the machine direction (MD) and the transverse direction (TD).
In certain exemplary embodiments, the ionic liquid material is comprised of an ionic liquid and a binder selected from the group consisting of a (meth)acrylic (co)polymer binder, a styrene-butadiene latex binder, a bio-based binder, or a combination thereof. In a specific embodiment, a liquid mixture (e.g., liquid solution) of ionic liquid choline dihydrogen phosphate can be added to a binder from the group as described herein (e.g., thermosetting binder, Acrodur thermosetting binder from BASF chemical company). In this specific embodiment, the thermosetting binder can be a binder that is relatively brittle when cured (e.g., heat is applied to the binder, etc.). As described herein, the addition of the ionic liquid choline dihydrogen phosphate has a plasticizing effect (e.g., acts as a plasticizer) on the thermosetting binder. That is, the nonwoven fibrous structure 234 is less brittle with the addition of the ionic liquid choline dihydrogen phosphate and thermosetting binder compared to a nonwoven fibrous structure with the addition of the thermosetting binder and no ionic liquid.
A number of devices can be utilized to remove excess liquid (e.g., water) from the nonwoven fibrous structure 234. In some exemplary embodiments calendering can be utilized to remove liquid from the nonwoven fibrous structure 234. Calendering can include a process of passing a nonwoven fibrous web through rollers with application of pressure to obtain a compressed and bonded fibrous nonwoven web. In certain exemplary embodiments, the number of devices can include a number of squeegees that can compress the nonwoven fibrous structure 234 and remove a portion of the liquid (e.g., water) that is applied to the nonwoven fibrous structure 234. In certain exemplary embodiments, the number of squeegees can be utilized before the nonwoven fibrous structure 234 is moved to a heating unit (e.g., oven, etc.) to remove liquid that was not removed by the number of squeegees. In other embodiments, the number of devices can be located at various points of the formation process of the nonwoven fibrous structure 234.
The heating unit can also be utilized for curing the ionic liquid material applied to the nonwoven fibrous structure 234. In some exemplary embodiments, the binder in the ionic liquid material is a thermosetting binder (e.g., a binder resin that hardens under heated conditions, etc.), wherein the binder and the ionic liquid of the ionic liquid material is cured with the heating unit. In addition, the heating unit can be utilized to remove liquid (e.g., water) that exists on and/or within the nonwoven fibrous structure 234. As described herein, the heating unit can remove liquid that remains after a number of devices are utilized to remove liquid. Removing the liquid can produce an ionic reinforcement material at locations where the ionic liquid material was applied to the nonwoven fibrous structure 234.
The ionic liquid material can bond a portion of the population of fibers with an ionic reinforcement material. In some exemplary embodiments, the ionic reinforcement material is a residual material of the ionic liquid material (e.g., material remaining after liquid is removed from the ionic liquid material). That is, in some exemplary embodiments, the ionic reinforcement material is the residual of the ionic liquid material after the liquid (e.g., water, excess water) is removed from the nonwoven fibrous structure 234. The ionic reinforcement material can provide an adhesive bond between the portion of the population of fibers when a binder is included in the ionic liquid material, as described herein.
The ionic reinforcement material can provide a number of characteristics to the nonwoven fibrous structure 234. The ionic reinforcement material can provide the number of characteristics when the ionic reinforcement material includes the ionic liquid or the ionic liquid and binder mixture as described herein. In some exemplary embodiments, the number of characteristics can include a fire retardant characteristic, an antistatic characteristic, an antibacterial characteristic, an antimicrobial characteristic, an antifungal characteristic, or a combination thereof. In certain exemplary embodiments, the ionic reinforcement material provides at least one of the number of characteristics. In some exemplary embodiments, the ionic reinforcement material provides a plurality of the number of characteristics as described herein. In some exemplary embodiments, the ionic reinforcement material can provide at least two of the number of characteristics listed herein.
In one exemplary embodiment, the ionic reinforcement material is applied to the nonwoven fibrous structure 234 with an ionic liquid material comprising the ionic liquid choline dihydrogen phosphate and a thermosetting binder. In this exemplary embodiment, the nonwoven fibrous structure 234 is less brittle with the addition of the ionic liquid choline dihydrogen phosphate and thermosetting binder compared to a nonwoven fibrous structure 234 with only the addition of the thermosetting binder. In addition, the nonwoven fibrous structure 234 comprises antistatic characteristics from the ionic reinforcement material. As described further herein, the addition of the ionic liquid choline dihydrogen phosphate and thermosetting binder to the nonwoven fibrous structure 234 can provide additional fire retardant (e.g., flame retardant) characteristics to nonwoven fibrous structure 234. The ionic reinforcement material can also add additional characteristics that can include: a fire retardant characteristic, an antistatic characteristic, an antibacterial characteristic, an antimicrobial characteristic, an antifungal characteristic, or a combination thereof.
As described herein, the ionic reinforcement material can increase the elongation (e.g., plasticity or fluidity) of the nonwoven fibrous structure 234. The ionic reinforcement material can also provide an increase in a tensile strength of the nonwoven fibrous structure 234. In some exemplary embodiments the ionic reinforcement material can provide an increase in a tensile strength of the nonwoven fibrous structure 234 and an increase in elongation of the nonwoven fibrous structure 234. In some exemplary embodiments, the increase in tensile strength and the increase in elongation are in the machine direction (MD) of the nonwoven fibrous structure 234.
A nonwoven fibrous structure 234 (e.g., fibrous web, air-laid nonwoven fibrous web, etc.) according to the present disclosure can be formed utilizing a number of forming methods (e.g., melt-spinning, air-laying, spun-bonding, carding, etc.). In exemplary embodiments, the nonwoven fibrous structure 234 is formed by air-laying fiber processing equipment, such as shown and described in U.S. Pat. Nos. 7,491,354 and 6,808,664.
In some exemplary embodiments, the air laying fiber processing equipment can use air flow to mix and inter-engage the fibers to form an air laid nonwoven fibrous structure. That is, the air laid nonwoven fibrous structure is formed by introducing a plurality of fibers into a forming chamber and dispersing the fibers within the forming chamber to form a population of individual fibers suspended in a gas, wherein the fibers are allowed to fall down to a collector.
In particular embodiments, instead of using strong air flow to mix and inter-engaged the fibers to form an air-laid nonwoven fibrous structure (such as with a “RandoWebber” web forming machine, available from Rando Machine Corporation, Macedon, N.Y.), the forming chamber can have spike rollers to blend and mix the fibers while gravity allows the fibers to fall down through the endless belt screen and form an air-laid nonwoven fibrous structure of inter-engaged fibers. With this construction of air-laying equipment, the fibers and the particulates are, in some exemplary embodiments, falling together to the bottom of the forming chamber to form the air-laid nonwoven fibrous structure. In one exemplary embodiment, a vacuum can be included below the area where the air-laid nonwoven fibrous structure forms in the forming chamber.
In some exemplary embodiments, the nonwoven fibrous structure 234 is formed using a carding process. An exemplary carding process is taught in, for example, U.S. Pat. No. 5,114,787. In some exemplary embodiments, the nonwoven fibrous structure 234 is formed by a meltblowing process. The meltblowing process is a method for forming a nonwoven fibrous structure by extruding a molten fiber-forming material through a plurality of orifices in a die to form fibers while contacting the fibers with air or other attenuating fluid to attenuate the fibers into fibers, and thereafter collecting the attenuated fibers. An exemplary meltblowing process is taught in, for example, U.S. Pat. No. 6,607,624.
The ionic liquid material can be applied to the nonwoven fibrous structure 234 at different stages of each of the forming methods. In some exemplary embodiments, as described herein, the ionic liquid material can be applied to fibers and/or filaments during a formation (e.g., in a forming chamber, etc.) of the fibers and/or filaments utilizing a mist process to spray the fibers and/or filaments while they are being collected on a collector. In some exemplary embodiments, as described herein, the ionic liquid material can be applied to the nonwoven fibrous structure 234 once the fibers and/or filaments are collected on a collector. In this embodiment, the ionic liquid material can be applied by known processing means such as roll coating, spray coating, and immersion coating and combinations of these coating techniques.
Nonwoven fibrous structures of the present disclosure and filter media including the same may, in some exemplary embodiments, advantageously incorporate a biodegradable material, a particulate material, a frame material, or a combination thereof. Some filter media incorporating biodegradable material (e.g. polyhydroxy alkonates (PHA), polyhydroxybutyrates (PHB), and the like) may, at the end of their useful life, be disposed of advantageously in municipal land-fills or industrial composting sites, thereby eliminating the need to return or otherwise recycle the spent filter media.
The operation of various embodiments of the present disclosure will be further described with regard to the following detailed Examples.
These Examples are merely for illustrative purposes and are not meant to be overly limiting on the scope of the appended claims. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Testing of the formed nonwoven fibrous webs was carried out using the testing apparatus listed in Table I, according to the methods described further below. In all testing procedures, a standard reference sample (i.e., comparative example), denoted “Std.” was measured for comparison. The standard reference samples (i.e., comparative examples) consisted of the corresponding web coated with binder only and no ionic liquid additive.
The basis weight of the nonwoven webs was measured with a Mettler Toledo XS4002S electronic balance.
Tensile strength and percent (%) elongation measurements were carried out on nonwoven samples (15×2.5 cm) on an Instron 5965 machine with a maximum load of 100N. For each nonwoven sample, three samples were measured and the average obtained.
Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight. Solvents and other reagents used may be obtained from Sigma-Aldrich Chemical Company (Milwaukee, Wis.) unless otherwise noted. In addition, Table II provides abbreviations and a source for all materials used in the Examples below:
In the following examples, “IL” denotes ionic liquid, “PET” denotes polyester, “MD” denotes machine direction, “TD” denotes transverse direction (relative to MD), “TS” denotes tensile strength, “elong” denotes percentage elongation, “PEG” denotes polyethylene glycol, “Std.” denotes a reference standard (i.e., a comparative example).
Acrodur 3530 (50% Solids Approx.):
Unless otherwise stated this binder was coated on the nonwoven web by roll coating pre-diluted in the ratio of 2:1 with H2O (33% solids approx.). The binder was then cured in a through air oven at 140° C. for approx. 4 minutes.
OC Biobinder (15% Solids Approx.):
Unless otherwise stated this binder was coated on the nonwoven web by roll coating pre-diluted in the ratio of 2:1 with H2O. The binder was then cured in a through air oven at 130° C. for approx. 4 minutes.
The ionic liquids (IL) listed in Table III were added at 10% w/v to the binder aqueous solutions. The ionic liquids were added in one part to the binder aqueous solution and stirred until fully dissolved.
Mixtures of fibers as listed in Table IV (i.e., viscose, PET, nylon) with low melting fibers were formed in a ratio of 80:20 fiber:low melting fiber ratio, and processing of the fiber mixtures was carried out using the nonwoven processing equipment listed in Table V.
Fiber prebonded webs were formed prior to coating of the resins. The required ratio of fibers to melty fibers were weighed and mixed by passing through a fiber opener. The air-laid prebonded webs were formed on a Rando Webber forming machine. Following forming of the web, it was sent through a through-air oven at 130° C. to yield a lightly bonded web suitable for coating trials.
The prebonded webs were coated by passing through roll coating cylinders containing the binder/ionic liquid mixture in the reservoir.
Tables 1-4 show the Tensile Test results for nonwoven viscose prebond webs with Acrodur binder and with various ionic liquids.
Tables 5-8 show the Tensile Test results for nonwoven viscose prebond webs with OC Biobinder binder and various ionic liquids.
Tables 9-12 show the Tensile Test results for nonwoven viscose prebond webs with Acrodur binder and various ionic liquids.
Tables 13-16 show the Tensile Test results for nonwoven viscose prebond webs with OC Biobinder binder and various ionic liquids.
Tables 17-18 show the Tensile Test results for nonwoven viscose prebond webs with Primal B15 binder and various ionic liquids.
The nonwoven samples tested consisted of viscose prebond webs. Tables 19-22 show the Tensile Test results for Example 4 with various ionic liquids.
The nonwoven samples tested consisted of viscose prebond webs. Tables 23-24 show the Tensile Test results for Example 5 with various ionic liquids.
The surface resistivity of the nonwoven coated samples was carried out according to VDE 0303 part 30. The test equipment consisted of a Teraohmmeter (PM 126 567), electrode (20 cm2) and Å Electrode (5 cm). The following terms are defined for the Surface Resistivity Test:
Tables 25-32 show the Surface Resistivity Test results for Example 1 with various ionic liquids.
Tables 33-43 show the Surface Resistivity Test results for Example 2 with various ionic liquids.
Tables 44-51 show the Surface Resistivity Test results for Example 3 with various ionic liquids.
Flame retardancy testing was carried out according to test method UL94 vertical burner test procedure with minor modifications. Methane gas at a pressure of 2.5 psi was used for the Bunsen burner. The flame cone height measurements were as follows: 1 cm for the interior and 2 cm for the exterior. The distance between the Bunsen tip and the end of the sample was 1 cm. The sample size was 15×2.5 cm. The sample measured consisted of a web of viscose fibers with the requisite binder containing 10% ionic liquid unless otherwise stated. 3 samples were measured for each binder/IL combination. When all 3 samples gave the same results, only 1 overall result is noted.
T1: Duration (seconds) of after flame after ignited Bunsen was applied to sample for 10 seconds
T2: After flame following application of Bunsen for a further 10 seconds
T3: After flame following application of Bunsen for a further 10 seconds B: Sample burned
Note: When after flame exposure result is equal to zero, this the sample resisted ignition.
Table 52 shows the Flame Retardancy Test results for Example 2 with various binders and ionic liquids.
Table 53 summarizes overall performance properties with respect to Tensile Strength, Anti-static properties, and Flame Retardancy.
Reference throughout this specification to “one embodiment,” “certain exemplary embodiments,” “one or more embodiments” or “an embodiment,” whether or not including the term “exemplary” preceding the term “embodiment,” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the certain exemplary embodiments of the present disclosure. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain exemplary embodiments,” “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment of the certain exemplary embodiments of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.
While the specification has described in detail certain exemplary embodiments, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these embodiments. Accordingly, it should be understood that this disclosure is not to be unduly limited to the illustrative embodiments set forth hereinabove.
Furthermore, all publications and patents referenced herein are incorporated by reference in their entirety to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. Various exemplary embodiments have been described. These and other embodiments are within the scope of the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US15/27869 | 4/28/2015 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61985107 | Apr 2014 | US |
