KR20050016282A - Antimicrobially-treated fabrics - Google Patents

Abstract

A method of forming an antibiotic treated fabric is provided. The method comprises forming a solution from a liquid and an antibiotic, for example 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride. In one embodiment, the cellulosic fibrous material is combined with the solution in a pulp to form a liquid suspension such that the antibiotic is present in the cellulosic fibrous material. The web is formed from an antibiotic treated cellulosic fibrous material such that substantially all of the cellulosic fibrous material present in the web is derived from an antibiotic treated cellulosic fibrous material. In one embodiment, the web of antibiotic treated fibrous material is also entangled with the nonwoven substrate. In some embodiments, when dried, the antibiotic forms a covalent bond with the cellulosic fibrous material.

Description

Antibiotic Treatment Fabric {ANTIMICROBIALLY-TREATED FABRICS}

In many different industries, microbial contamination can be a serious problem. For example, in the food service industry, food is often manufactured on hard surfaces such as counters, dining tables, and the like. Microorganisms (such as viruses, bacteria, fungi, etc.) of these products can be collected on the surface and transferred to dishcloths, towels or wipes that are later used to clean the surface. After being transferred, the microorganisms may remain in dishcloths, towels or wipes to grow and begin to colonize because of the favorable environment often provided by the material. Thus, the microorganisms can actually cross-contaminate other environments, such as other surfaces, the user's hands or skin, etc. when in contact.

In an attempt to prevent surface and cloth contamination, wipers containing specific antibiotics have been used. For example, many of these antibiotic wipers are impregnated with antibiotics that are delivered to the user in a premoistened form. However, disinfectants in the wiper are easily consumed after a short time. Thus, the wet wiper can only be used to only slightly inhibit growth or very limited number of wipes on the wiper and / or the hard surface being cleaned.

Other types of wipers have also been developed to provide antibiotic activity. For example, one wiper is described in US Pat. No. 4,929,498 (Suskind et al.). In particular, the wipers described in Suskins et al are formed from fibers and nonwoven fabrics containing antibiotics (preferably organosilicon quaternary ammonium salts) distributed between 10% and 50% of the fibers. Antibiotics are said to be substantive to the fiber and thus are substantially prevented from diffusing therefrom. However, while the wiper can overcome the problem of conventional wet wipers where antibiotics are easily consumed, the wiper still tends to provide inadequate microbial mortality.

Other common wipers, known as "Keri Klean" food service wipers, are formed from a dry lay carding process from rayon and polyester fibers. The fibers are then hydroentangled and then saturated in a bath containing antibiotics. After the antibiotic is applied, the liquid is squeezed out of the nonwoven and then the nonwoven is dried. However, one problem with the method is that additional equipment may be required to “soak and squeeze” the nonwoven into the antibiotic bath. The additional equipment can increase the cost as well as reduce the efficiency of the process.

Accordingly, there is a need for a more effective method of forming antibiotic nonwoven products such as cloth, towels or wipes.

<Overview of invention>

According to one embodiment of the invention, there is provided a method of forming an antibiotic treated fabric comprising forming a solution from a liquid and an antibiotic. In general, any of a variety of antibiotics may be used in the present invention. For example, in some embodiments, the antibiotic is an organosilicon quaternary ammonium compound. One suitable organosilicon quaternary ammonium compound that may be used in the present invention has the following structure:

Wherein R ₁ is hydrogen or a C ₁ -C ₈ alkyl group;

R ₂ is hydrogen or a C ₁ -C ₈ alkyl group;

R ₃ and R ₄ are the same or different and are selected from the group consisting of hydrogen and C ₁ -C ₄ alkyl groups;

R ₅ is hydrogen or a C ₁ -C ₃₀ alkyl group;

X ⁻ is a suitable counter ion.

For example, in one embodiment, the antibiotic is 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride.

The cellulosic fibrous material is combined with the solution to form a liquid suspension, where the antibiotic is combined with it and then is present in the cellulosic fibrous material. Antibiotics can be up to about 5% by weight of the treated fibrous material, in some embodiments from about 0.04% to about 1.0% by weight of the treated fibrous material, and in some embodiments from about 0.2% to about 0.5% by weight of the treated fibrous material. It may be present in the solution in an amount of. In some embodiments, the cellulosic fibrous material and the antibiotic solution are combined in a pulper. The material may also be agitated if necessary to enhance the likelihood that substantially all antibiotics will be present in the cellulosic fibrous material.

The liquid suspension is then formed into the web using any of a variety of techniques such that substantially all of the cellulosic fibrous material present in the web is derived from antibiotic treated cellulosic fibrous material. In some embodiments, the web of antibiotic treated fibrous material may also be entangled with the nonwoven substrate. The nonwoven substrate may be formed from a continuous filament such as formed by a spunbond process. In some embodiments, the web of antibiotic treated fibrous material is subsequently dried to allow the antibiotic to form a covalent bond with the cellulosic fibrous material.

In some embodiments, at least part of the liquid is removed from the liquid suspension during formation of the fabric as described above. The removal can be accomplished in a variety of different ways such as using gravity, the use of vacuum boxes or shoes, dryers, and the like. However, regardless of the mechanism used to remove the liquid, some of the liquid removed is substantially free of antibiotics. Thus, the liquid can sometimes be recycled or discarded without requiring additional mechanical or chemical treatment.

Other features and aspects of the present invention are discussed in more detail below.

The complete and feasible disclosure of the present invention, including the best mode presented to those skilled in the art, is described in more detail in the remainder of this specification with reference to the accompanying drawings.

1 is a schematic of a process for incorporating antibiotics into the pulp of a papermaking process.

2 is a schematic diagram of a process for forming a entangled web according to one embodiment of the present invention.

3 is a SEM photograph (magnification 80X) of a cross section of a composite fabric formed according to one embodiment of the present invention.

Repeat use of reference signs in the present specification and drawings is intended to represent the same or similar features or elements of the invention.

Reference will now be made in detail to various embodiments of the invention, one or more examples of which are described below. Each example is provided by way of explanation of the invention, not limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features depicted or described as part of one embodiment may be used in another embodiment to make another further embodiment. Accordingly, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

<Definition>

As used herein, the term "nonwoven or nonwoven web" refers to a web having a structure in which the individual fibers or threads are interlaced in a manner that is not as identifiable as in knitted fabrics. Nonwoven or nonwoven webs are formed from many processes, such as, for example, melt blowing processes, spunbonding processes, and bonded carded web processes. The basis weight of a nonwoven is usually expressed in ounces (osy) or grams per square meter (gsm) of material per square yard, and useful fiber diameters are typically expressed in microns (multiplying osy by 33.91 to convert osy to gsm). .

As used herein, the term "fine fibers" means small diameter fibers having an average diameter of no greater than about 75 microns, for example, about 0.5 to about 50 microns, especially about 2 to about 40 microns. .

As used herein, the term “meltblown fiber” refers to a molten thermoplastic by extruding the molten thermoplastic into a concentrated high velocity gas (eg, air) stream through a plurality of fine, usually circular die capillaries as molten threads or filaments. It means a fiber having a fine fiber diameter by reducing its diameter by thinning the filament. The meltblown fibers are then carried by the high velocity gas stream and stacked on a collecting surface to form a web of disordered meltblown fibers. Such a process is disclosed, for example, in US Pat. No. 3,849,241 (Butin et al.), Which is hereby incorporated by reference in its entirety. Meltblown fibers generally can be continuous or discontinuous, and generally fibers smaller than 10 microns in diameter and generally bond when stacked on a collecting surface.

As used herein, the term “spunbonded filament” refers to extruding a molten thermoplastic material as a filament from a plurality of fine, generally circular capillaries of a spinneret, and then, for example, drawing an elongate diameter of the extruded filament. And / or small diameter substantially continuous filaments formed by abrupt reduction by other known spunbonding mechanisms. The manufacture of spunbonded nonwoven webs is described, for example, in US Pat. No. 4,340,563 (Appel et al.) And US Pat. No. 3,692,618 (Dorschner et al.), US Pat. 3,802,817 (Matsuki et al.), US Pat. Nos. 3,338,992 and 3,341,394 (Kinnev), US Pat. Nos. 3,502,763 (Hartman), US Pat. No. 3,502,538 (Levy) ), US Pat. No. 3,542,615 (Dobo et al.) And US Pat. No. 5,382,400 (Pike et al.). Spunbond filaments are generally not tacky when they are stacked on the collecting side. The diameter of the spunbond filaments can sometimes be less than about 40 microns, often from about 5 to about 20 microns.

The term 'pulp' as used herein refers to fibers from natural sources such as woody and non-woody plants. Woody plants include, for example, deciduous and coniferous trees. Non-woody plants include, for example, flax, esparto grass, milkweed, straw, jute, hemp and vargas.

As used herein, the term 'average fiber length' refers to the weighted average length of pulp fibers determined using Kazani Fiber Analyzer Model No. FS-100 available from Kajaani Oy Electronics, Kazani, Finland. . According to the test procedure, pulp samples are treated with dissociation solution to ensure that no fiber bundles or flakes are present. Each pulp sample is disintegrated into hot water and diluted with approximately 0.001% solution. Upon testing using standard Kazani fiber analysis test procedures, individual test samples are drawn from the dilute solution in about 50-100 ml portions. The weighted average fiber length can be represented by the following formula:

In the formula,

k is the maximum fiber length,

x _i is fiber length,

n _i is the number of fibers of length x _i ,

n is the total number of fibers measured.

As used herein, the term 'low average fiber length pulp' refers to pulp containing a significant amount of short and non-fiber particles. Many secondary wood fiber pulp can be considered as low average fiber length pulp. However, the quality of the secondary wood fiber pulp depends on the quality of the recycled fiber and the type and amount of previous processing. Low average fiber length pulp may have an average fiber length of less than about 1.2 mm as measured by an optical fiber analyzer such as, for example, Kazani Fiber Analyzer Model No. FS-100 (Kazani Oy electronics, Kazani, Finland). . For example, the low average fiber length pulp may have an average fiber length of about 0.7 to 1.2 mm. Exemplary low average fiber length pulp includes virgin hardwood pulp, and secondary fiber pulp from resources such as paper waste, newsprint and cardboard waste.

As used herein, the term 'high average fiber length pulp' refers to pulp containing relatively small amounts of short and non-fiber particles. High average fiber length pulp is typically formed from certain non-secondary (ie raw) fibers. Selected secondary fiber pulp may also have a high average fiber length. High average fiber length pulp typically has an average fiber length of greater than about 1.5 mm as measured by an optical fiber analyzer such as, for example, Kazani Fiber Analyzer Model No. FS-100 (Kazani Oy electronics, Kazani, Finland). . For example, the high average fiber length pulp may have an average fiber length of about 1.5 to about 6 mm. One example of high average fiber length pulp, which is wood fiber pulp, includes bleached and unbleached raw softwood fiber pulp.

As used herein, the phrase “antibiotic” or “antibiotic” includes Escherichia coli (ATCC # 11229), Staphylococcus aureus (ATCC # 6538) (both bacteria), and / or Candida albicans (Candida albicans; ATCC # 10231) shows a composition or moiety that can prevent the growth of (yeast). For example, in some embodiments, the lethality of the aforementioned microorganisms is ASTM No. E2149-01 (title "Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions").

<Detailed Description>

The present invention generally relates to a method of forming an antibiotic treated fabric in which the antibiotic is present in the cellulosic fibrous material during the papermaking process. For example, in one embodiment, the organosilicon quaternary ammonium compound is initially applied to a pulp containing a liquid (eg, water). The cellulosic fibrous material is then applied to the pulp and mixed under antibiotic treatment with water. Because of the partial negative charge present on the cellulose fibers, it is believed that the cationic quaternary ammonium groups of the organosilicon quaternary ammonium antibiotics can form associative bonds with pulp fibers. In addition, once associated with the antibiotic, the fibrous material may be formed into a cellulosic web. When dried, the antibiotic cures, thereby forming a covalent bond with the cellulosic fibers. Surprisingly, it has been found that any water removed during the papermaking process may be substantially free of any residual antibiotics, whereby it may be recycled or discarded without any additional mechanical or chemical treatment.

In general, any of a variety of antibiotics that may be present in the cellulosic fibrous material may be used in the present invention. For example, in some embodiments, the antibiotic can be an organosilicon compound. Some examples of organosilicon compounds believed to be suitable for use in the present invention are ammonium salts, ie di-isobutylcresoxyethoxyethyl dimethyl benzyl ammonium chloride, di-isobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride, myristyl Dimethylbenzyl ammonium chloride, myristyl picolinium chloride, N-ethyl morpholinium chloride, laurylisoquinolinium bromide, alkyl imidazolinium chloride, benzalkonium chloride, cetyl pyridinium chloride, coconut dimethyl benzyl ammonium chloride , Stearyl dimethyl benzyl ammonium chloride, alkyl dimethyl benzyl ammonium chloride, alkyl diethyl benzyl ammonium chloride, alkyl dimethyl benzyl ammonium bromide, di-isobutyl phenoxyoxyethyl trimethyl ammonium chloride, di-isobutylphenoxyethoxyethyl dimethylKyl ammonium chloride, methyl-dodecylbenzyl trimethyl ammonium chloride, cetyl trimethyl ammonium bromide, octadecyl dimethyl ethyl ammonium bromide, cetyl dimethyl ethyl ammonium bromide, octades-9-enyl dimethyl ethyl ammonium bromide, dioctyl dimethyl ammonium chloride, dodecyl Trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium iodide, organosilicon derivatives of octyl trimethyl ammonium fluoride, and mixtures thereof. Other examples of suitable organosilicon compounds include US Pat. No. 3,719,697 (Michael et al.), Which is incorporated herein by reference in its entirety; 3,730,701 (Isquith et al.); 4,395,454 (Klein); 4,615,937 (Bouchette); And 6,136,770 (Cheun et al.).

One specific example of a suitable organosilicon compound is a silane quaternary ammonium compound having the structure:

Wherein R ₁ is hydrogen or a C ₁ -C ₈ alkyl group (eg CH ₃ );

R ₂ is hydrogen or a C ₁ -C ₈ alkyl group;

R ₃ and R ₄ may be the same or different and may be selected from the group consisting of hydrogen and a C ₁ -C ₄ alkyl group (eg CH ₃ );

R ₅ is hydrogen or a C ₁ -C ₃₀ alkyl group (eg C ₁₈ H ₃₇ );

X ⁻ is a suitable counterion, for example halogen ions (eg Cl ⁻ or Br ⁻ ).

A commercial example of the silane quaternary ammonium compound is AEM 5772, which can be obtained from Aegis Environments Co., Midland, Michigan, USA. In particular, AEM 5772 contains 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride of the formula:

The quaternary compound in AEM 5772 is contained in the water / methanol mixture in an amount of 72% by weight of the solution.

In accordance with the present invention, antibiotics as described above may generally be combined with cellulosic fibrous materials at various different stages of the papermaking process. Usually, antibiotics are added during the preparation of the fibrous slurry used to form the web. For example, referring to FIG. 1, one embodiment of a process for treating cellulosic fibers with antibiotics is shown. Specifically, a liquid (usually water) is initially provided in a conventional papermaking fiber stock preparation beater or pulper 13. Thereafter, an antibiotic is applied to the pulp 13. In some embodiments, the antibiotic may be hydrolyzed by water in the pulp 13. For example, in one embodiment, 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride is hydrolyzed by water in pulp 13. However, it should be understood that antibiotics can also be hydrolyzed prior to addition to the pulp 13. Moreover, in some cases antibiotics may not require hydrolysis at all.

The amount of antibiotic added to the pulp 13 can generally vary as needed. For example, in some embodiments, the antibiotic is about 5% or less by weight of the treated fibrous material, in some embodiments, from about 0.04 to about 1.0% by weight of the treated fibrous material, and in some embodiments, about 0.2% of the treated fibrous material. To the pulp 13 in an amount of from about 0.5% by weight.

Once optionally hydrolyzed, the cellulosic fibrous material can be applied to the pulp 13. Any of a variety of cellulosic fibrous materials can generally be used in the present invention. For example, the cellulosic fibrous material may include pulp fibers, synthetic cellulosic fibers, modified cellulosic fibers, blends thereof, and the like. Some examples of suitable cellulosic fiber sources include raw wood fibers such as thermomechanical, bleached and unbleached softwood and hardwood pulp. Secondary or recycled fibers may also be used, such as those obtained from paper scrap, newsprint, brown paper stock, cardboard scrap, and the like. In addition, vegetable fibers such as manila hemp, flax, milkweed, cotton, modified cotton, cotton linter may also be used. In addition, synthetic cellulose based fibers such as, for example, rayon and viscose rayon can be used. Modified cellulose based fibers may also be used. For example, the fibrous material may consist of derivatives of cellulose formed by substitution of appropriate radicals (eg, carboxyl, alkyl, acetate, nitrates, etc.) of hydroxyl groups along the carbon chain. These fibers may be used alone or in combination with other cellulosic and / or noncellulosic fibers. Particles and / or other materials may also be used with the fibrous material.

When used, the pulp fibers may have any high average fiber length pulp, low average fiber length pulp or mixtures thereof. High average fiber length Pulp fibers usually have an average fiber length of about 1.5 mm to about 6 mm. Some examples of such fibers include northern softwood, southern softwood, cedar, cedar, hemlock, pine (e.g. southern pine), spruce (e.g. black spruce), Combinations thereof, and the like, but may not be limited thereto. Examples of high average fiber length wood pulp include those available under the trade name "Longlac 19" from Kimbery-Clark Corporation.

Low average fiber length pulp may be, for example, some raw hardwood pulp and secondary (ie, recycled) fiber pulp from sources such as, for example, newspaper paper, recycled cardboard, and paper waste paper. Hardwood fibers such as eucalyptus, maple, birch, aspen and the like can also be used. Low average fiber length Pulp fibers usually have an average fiber length of less than about 1.2 mm, for example 0.7 mm to 1.2 mm. The mixture of high average fiber length and low average fiber length pulp may contain a significant proportion of low average fiber length pulp. For example, the mixture may contain more than about 50 weight percent low average fiber length pulp and less than about 50 weight percent high average fiber length pulp. One exemplary mixture contains 75% by weight low average fiber length pulp and about 25% high average fiber length pulp.

Once fed to the pulper 13, the fibrous slurry can be maintained under continuous stirring to form a liquid suspension. Although not required, the continuous agitation can ensure that the fibrous material and the liquid suspension of the antibiotic are well mixed to improve the uniformity of the antibiotic distribution throughout the fibrous slurry. However, it should be understood that if desired, excessive agitation can be harmful to antibiotics or fibrous materials, where the agitation can be stopped or used intermittently.

While present in the pulp 13, the antibiotic may be present in the cellulosic fibrous material. Specifically, partially charged groups (eg, hydroxy moieties) present on the cellulosic fibers may form an associative bond with the positively charged quaternary ammonium moiety of the antibiotic. Moreover, when continuously stirred as described above, the antibiotic is more likely to come into contact with any free partially charged groups on the cellulosic fibers. Thus, substantially all antibiotics present in the pulp 13 can be associated with the fibrous material. Thus, any liquid removed later during the papermaking process, such as through gravity, vacuum boxes or shoes, dryers, etc., contains substantially antibiotics so that they can be recycled or discarded without requiring the use of any mechanical or chemical treatment agents. You can't.

After the antibiotic is mixed with the fibrous material in the pulp 13, the resulting fibrous slurry 17 is optionally formed into a layer of fibrous material or cellulosic web using conventional wet-laying or papermaking techniques. Can be diluted and prepared. If desired, the fibrous slurry 17 may be stored in a machine chest 15 prior to web formation. Moreover, the pH of the fibrous slurry 17 can be adjusted for device compatibility if desired. While antibiotics and fibrous materials are described as being mixed in the pulper 13 in the embodiments below, it should be understood that the materials may also be mixed at any stage during the papermaking process prior to or during the formation of the cellulosic web. For example, in one embodiment the antibiotic and fibrous material may be mixed together in the machine chest 15.

Other additives may also be added at the pulp 13, machine chest 15 or just prior to formation. The additive may be added to improve fastness and other properties such as softness and wet-strength. For example, in some embodiments, small amounts of wet strength resins and / or resin binders may be added to improve strength and wear resistance. Useful binders and wet strength resins include, for example, Kymene 557 H (available from Hercules Chemical Company) and Parez 631 (available from American Cyanamid, Inc.). Include. Crosslinkers and / or hydrating agents may also be added to the pulp mixture. If a very open or loose nonwoven pulp fiber web is desired, debonder may be added to the pulp mixture to reduce hydrogen bonding. One exemplary debonder is available under the trade name Quaker 2008 from the Quaker Chemical Company (Conshohoken, Pennsylvania, USA). For example, the addition of certain debonders in amounts of from 1 to 4% by weight of the composite material reduces the measured static and dynamic coefficients of friction and improves the wear resistance of the continuous filament-rich side of the composite fabric.

With reference to FIGS. 1-2, the fibrous slurry 17 is then conveyed from the machine chest 15 to the conventional papermaking headbox 12 and accumulated on the conventional forming fabric or surface 16 through the outlet 14. The suspension of the treated cellulosic fibrous material may have any consistency generally used in conventional papermaking processes. For example, the suspension may contain from about 0.01 to about 1.5 weight percent of the treated cellulosic fibrous material suspended in water. Water is then removed from the suspension of treated cellulosic fibrous material to form a uniform layer of cellulosic fibrous material 18.

The nonwoven substrate 20 is also released from the feed roll 22 and moves in the direction indicated by the arrow associated therewith as the feed roll 22 rotates in the direction of the arrow associated therewith. The nonwoven substrate 20 passes through the nip 24 of the S-roll arrangement 26 formed by the stack rollers 28 and 30.

Nonwoven substrate 20 may be formed from a variety of different materials by a variety of different processes. For example, nonwoven substrate 20 may be formed from continuous filaments, staple fibers, and the like. The continuous filaments can be produced, for example, by known continuous filament nonwoven extrusion processes, for example by known solvent spinning or melt-spinning processes, which can be passed directly through the nip 16 without first being stored in a feed roll. have. In one embodiment, nonwoven substrate 20 is a nonwoven web of continuous melt spun filament formed by a spunbond process. Spunbond filaments may be formed from any melt-spun polymer, copolymer or blends thereof. For example, spunbond filaments are polyolefins, polyamides, polyesters, polyurethanes, AB and ABA 'block copolymers, where A and A' are thermoplastic endblocks and B is an elastomeric midblock ), And copolymers of ethylene and at least one vinyl monomer, such as vinyl acetate, unsaturated aliphatic monocarboxylic acids and esters of such monocarboxylic acids. When the filaments are formed from polyolefins, such as polypropylene, the nonwoven substrate 20 may have about 3.5 to about 150 grams per square meter (gsm), in some embodiments about 5 to about 70 gsm, in some embodiments about 10 And a basis weight of from about 35 gsm. The polymer may include additional materials such as pigments, antioxidants, flow promoters, stabilizers, and the like.

Nonwoven substrate 20 may be bonded to improve the durability, strength, hand, aesthetics, and / or other properties of substrate 20. By way of example only, nonwoven substrate 20 may be thermal, ultrasonic, adhesive, and / or mechanically coupled. Nonwoven substrate 20 is preferably pattern bonded. By way of example, the nonwoven substrate 20 may be point bonded to provide a fabric having many small discrete bonding points. An exemplary bonding process is thermal point bonding, which generally involves passing one or more layers to be bonded between a heated roll, such as an engraved patterned roll and a second bonding roll. The piece roll is patterned in such a way that the fabric does not bond on its entire surface, and the second roll may be smooth or patterned. As a result, various patterns for engraving rolls were developed for aesthetic as well as functional reasons. Exemplary binding patterns include US Pat. No. 3,855,046 (Hansen et al.), US Pat. No. 5,620,779 (Levy et al.), US Pat. No. 5,962,112 (Hynes et al., Incorporated herein by reference in their entirety). ), US Patent No. 6,093,665 (Savovitz et al.), US Chairman 428,267 (Romano et al.) And US Chairman 390,708 (Brown). . For example, in some embodiments, nonwoven substrate 20 may be optionally bonded to have a total bond area of less than about 30% and a uniform bond density of more than about 100 bond points per in ² . For example, the nonwoven substrate 20 may have about 2 to about 30% total bond area, and about 250 to about 500 individual link density dot pin bonds per in ² of (conventional optically measured with a microscope method). This combination of total bond area and bond density can be achieved in some embodiments by combining the nonwoven substrate 20 with a pin bond pattern having at least about 100 pin bond points per in ² , which is sufficient with a smooth anvil roll. Provides less than about 30% total bonding surface area upon contact. In some embodiments, the bonding pattern can have a pin bond density of about 250 to about 350 pin bond points per in ² , and can have a total bond surface area of about 10% to about 25% when in contact with a smooth anvil roll. have.

In addition, the nonwoven substrate 20 may be joined in a continuous seams or pattern. As an additional example, the nonwoven substrate 20 may be bonded along the outer periphery of the sheet or simply across the width or transverse direction (CD) of the fabric adjacent the edge. Other bonding techniques may also be used, for example a combination of thermal bonding and latex impregnation. Alternatively and / or additionally, a resin, latex or adhesive may be applied to the nonwoven substrate 20 by, for example, spraying or printing, and dried to provide the desired bond. Other suitable binding techniques are described in US Pat. Nos. 5,284,703 (Everhart et al.), 6,103,061 (Anderson et al.) And 6,197,404 (Varona), which are hereby incorporated by reference in their entirety. It is.

The treated cellulosic fibrous layer 18 is laminated onto the nonwoven substrate 20 over the porous entangled surface 32 of a conventional entanglement machine. Although not required, it is preferred that the treated cellulosic fibrous layer 18 is located between the nonwoven substrate 20 and the entangled manifold 34. The treated cellulosic fibrous layer 18 and the nonwoven substrate 20 pass under one or more entanglement manifolds 34 and are treated with a fluid jet to treat the treated cellulosic fibrous material with the filaments of the continuous filament nonwoven substrate 20. Entangle The fluid jet also advances the cellulosic fibers through the nonwoven substrate 20 into the substrate to form the composite material 36.

Alternatively, entanglement may occur while the treated cellulosic fibrous layer 18 and the nonwoven substrate 20 are located on the same porous screen (ie, reticulated fabric) where wet lamination occurs. The invention also superimposes the dried cellulose-based fibers on a continuous filament nonwoven substrate, rehydrates the dried sheet to a certain concentration and then entangles the rehydrated sheet.

The treated cellulosic fibrous layer 18 may be highly saturated with water and entanglement may occur. For example, the treated cellulosic fibrous layer 18 may contain up to about 90% by weight of water just prior to entanglement. Alternatively, the treated cellulosic fibrous layer can be an air-laid or dry-laid layer.

The entanglement of the wet laminated layer of treated cellulosic fibrous material is preferred, because the cellulosic fibers are embedded in the continuous filament substrate without interfering with the "paper" bonds (sometimes called hydrogen bonds). And / or entangled and entangled with the continuous filament substrate. "Paper" bonding also appears to improve the wear resistance and tensile properties of high pulp content composite fabrics.

Entangling can be accomplished using, for example, conventional entangling devices as disclosed in US Pat. No. 3,485,706 (Evans), the disclosure of which is incorporated herein by reference. The entanglement of the present invention can be carried out using a suitable working fluid such as water. The working fluid flows through a manifold that evenly distributes the fluid to a series of individual holes or orifices. The diameter of the hole or orifice may be about 0.003 to about 0.015 inches. For example, a manifold manufactured by Honeycomb Systems Incorporated, Bideford, Maine, USA, which includes a strip having an orifice of 0.007 inch diameter, 30 holes per inch, and a row of holes. It is available. However, it should be understood that many other manifold forms and combinations may be used. For example, a single manifold can be used or a plurality of manifolds can be arranged in series.

In the entangling process, the working fluid generally passes through the orifice at a pressure of about 200 to about 2000 psig. In some embodiments, the composite fabric may be processed at a rate of about 1000 feet per minute (fpm) upon treatment at the upper limit of the pressure. The fluid impacts the cellulosic fibrous layer 18 and the nonwoven substrate 20, which are supported by a porous surface, which may be, for example, a cross-sectional mesh having a mesh size of about 40 × 40 to about 100 × 100. The porous surface may also be multiple meshes with a mesh size of about 50 × 50 to about 200 × 200. As is typical of many soot treatment methods, the vacuum slot 38 may be located directly below the hydro-needling manifold or below the porous entanglement surface 32 downstream of the entanglement manifold, thus excess Of water is recovered from the entangled composite material 36.

Although not supported by any particular theory, the columnar jet of working fluid that directly impacts the cellulosic fibers deposited on the nonwoven substrate performs the function of partially passing the fibers into a matrix or nonwoven network structure of filaments in the substrate. I think. When the fluid jet and the cellulosic fibers interact with the nonwoven substrate, the cellulosic fibers also become entangled with the filaments of the nonwoven substrate and the fibers. In addition to causing the fibers to entangle each other, entanglement also forms wrinkles or heat in the material, which may be desirable for aesthetic and / or other purposes. For example, as shown in FIG. 3, the entangled composite material 100 includes pleats or rows 90 defined by entangled fibers 92.

If desired, the energy of the fluid jet impacting the cellulosic fibrous layer 18 and the substrate 20 is inserted into the continuous filament substrate 20 and entangled with the substrate in such a way that the cellulosic fibers reinforce both sides of the fabric. It can be adjusted to. That is, the entanglement can be adjusted to produce a high cellulosic fiber concentration on one side of the fabric and a low cellulosic fiber concentration on the opposite side. The shape described above may be particularly useful for special purpose wipers and personal care products such as, for example, disposable diapers, sanitary napkins, adult incontinence products, and the like. Alternatively, substrate 20 may be entangled with a cellulosic fibrous layer on one side and another cellulosic fibrous layer on the other side to form a fabric having two cellulose rich sides. In such cases, entanglement of both sides of the composite fabric may be desirable.

According to the present invention, it has surprisingly been found that the associative bonds formed between antibiotics and pulp fibers during the preparation of the stock solution are not substantially destroyed by the mechanical forces of the entanglement process. In particular, it is believed that, upon application to the entanglement conditions as described above, the associative bond between the quaternary ammonium portion of the antibiotic and the partially charged hydroxy group of the pulp fiber may be strong enough to remain intact after being entangled. . While not supported by theory, it is believed that in some embodiments the result is at least partially caused by the mixture of fibers and antibiotics under continuous stirring. Specifically, as described above, agitation can cause the untreated fiber to come into contact with any unused antibiotic. As a result, virtually all antibiotics can bind to fibers, thereby enhancing treatment durability even when applied to relatively strong mechanical forces during entanglement.

After the fluid jet treatment, the composite fabric 36 can be transferred to an uncompressed drying process. Different speed pickup rolls 40 may be used to transfer the material from the hydraulic needling belt to the uncompressed drying process. Alternatively, conventional vacuum pickup and transfer fabrics can be used. If desired, the composite fabric may be wet-creping prior to being transferred to the drying process. Uncompressed drying of the web can be accomplished using a conventional rotary drum through-air drying apparatus 42. The through-drier 42 may be an outer rotary cylinder 44 with a perforation 46, in combination with an outer hood 48 for receiving hot air passing through the perforation 46. The aeration dryer belt 50 carries the composite fabric 36 over the top of the aeration dryer outer cylinder 40. Hot air applied through the perforations 46 in the outer cylinder 44 of the aeration dryer 42 removes water from the composite fabric 36. The temperature of the air forcedly blown through the composite fabric 36 by the aeration dryer 42 may be between about 200 ° F. and about 500 ° F. Other useful aeration drying methods and apparatus are described, for example, in US Pat. Nos. 2,666,369 (Niks) and 3,821,068 (Shaw), which are hereby incorporated by reference in their entirety.

As mentioned above, when dried, the antibiotic is covalently bound to the cellulosic fibers. For example, in one embodiment, the organosilicon antibiotic compound is believed to form siloxane bonds (ie, O—Si—O) with the free hydroxy groups of the cellulosic fibers. By forming covalent bonds with the cellulosic fibers, antibiotic treatment durability can be significantly improved to provide antibiotic activity to the fabric for a long time.

It may also be desirable to use a finishing and / or post-treatment process to impart selected properties to the composite fabric 36. For example, the fabric may be slightly pressed, creped, brushed or enhanced by a calender roll and / or to provide a uniform appearance and / or any tactile properties. It may be treated differently. Alternatively or additionally, various chemical post-treatments such as adhesives or dyes may be added to the fabric. Additional post-treatment agents that can be used are described in US Pat. No. 5,853,859 (Levy et al.), Which is incorporated herein by reference in its entirety.

The resulting composite fabric 36 may generally have any desired content of antibiotic treated cellulosic fibers. For example, in some embodiments, the antibiotic treated cellulosic fibers may comprise more than about 50% of the weight of the fabric 36, and in some embodiments, from about 60% to about 90% of the weight of the fabric 36. . Generally speaking, substantially all the cellulosic fibers used to form the fabric 36 are antibiotic treated. For example, in some embodiments, at least about 90% of the cellulosic fibers used to form the fabric 36 are antibiotic treated. Moreover, depending on the desired antibiotic activity, the fabric 36 may also contain varying levels of antibiotic. For example, in some embodiments, the fabric 36 may have antibiotic up to about 4% of the fabric weight, in some embodiments from about 0.03% to about 0.8% of the fabric weight, and in some embodiments, from about 0.16% of the fabric weight to It may be contained in an amount of about 0.4%.

The invention can be better understood with reference to the following examples.

<Example 1>

The ability to form fabrics using antibiotic treated cellulosic fibers was demonstrated. Specifically, six samples were produced by initially adding variable amounts of AEM 5772 (see Table I) to 1260 pounds of tap water contained in pulper. With continuous stirring, 15 pounds of pulp mixture (50 wt% northern softwood kraft fiber and 50 wt% southern softwood kraft fiber) was added to the pulp so that each resulting slurry had a 1.19% solids concentration. The slurry was mixed for 10 minutes and fed to a dilution tank where it was diluted to 0.1% solids concentration with tap water.

The resulting slurry was then used to form the composite fabric according to US Pat. No. 5,204,703 (Eberhard et al.). Specifically, the treated pulp fibers were entangled with a polypropylene spunbond web (based weight 27 grams per square meter) at a entanglement pressure of about 1800 pounds per square inch or less. The entangled fabric was then dried for 1 minute using an aeration dryer (air at 450 ° F. temperature) to allow the fabric to reach a maximum temperature of 200 ° F. The basis weight of the resulting fabric was 125 grams per square meter.

Once formed, the antibiotic activity of each fabric sample was determined by ASTM No. E2149-01 (title "Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions"). The properties of the samples are shown in Table I below.

Characteristics of the sample Sample AEM 5772 (72% solids) added (g) AEM 5772 pulp addition amount ([AEM solids weight / pulp weight] x 100%) AEM 5772 Fabric Addition ([AEM Solids Weight / Fabric Weight] × 100%) % Bacteria reduction One 0.0 0.00 0.000 0 2 54.5 0.58 0.450 > 97 3 27.2 0.29 0.230 > 97 4 13.6 0.14 0.110 97 5 6.8 0.07 0.055 89 6 3.4 0.04 0.031 81

Thus, as the results of Table I show, it is possible to provide fabrics with relatively high bacterial mortality, such as greater than 97%.

In addition, to determine the amount of AEM 5772 depleted from the water-pulp slurry during pulp preparation, samples of AEM 5772 treated pulp slurry were subjected to pulp, machine chest, headbox, and post-entangling white water. Taken from silo. The pulp slurry was dewatered and the captured water samples were tested by an active quaternary titration method using sodium lauryl sulfate, chloroform, dye and buffer, respectively. No AEM 5772 quaternary silicon was detected in any of the collected water.

<Example 2>

The ability to form fabrics using antibiotic treated cellulosic fibers was demonstrated. Specifically, two samples were produced by initially adding AEM 5772 (see Table II) to 30,000 pounds of mill water in the pulp. Prior to application to the pulper, AEM 5772 was diluted to 2% solids level with water.

With continuous stirring, 2000 pounds of pulp mixture (50 wt% northern softwood kraft fiber and 50 wt% southern softwood kraft fiber) was added to the pulp so that each resulting slurry had a 6% solids concentration. The slurry was mixed for 10 minutes and fed to a dilution tank where it was diluted to 2.5% solids concentration with tap water.

The resulting slurry was then used to form the composite fabric according to US Pat. No. 5,204,703 (Eberhard et al.). Sample 1 was formed in the same manner except that sample 2 was not creped but sample 2 was creped. For example, during processing, the treated pulp fibers of each sample were initially diluted to 0.3% solids concentration. Treated pulp fibers were entangled with polypropylene spunbond webs (based on 27 grams per square meter) at a entanglement pressure of about 1800 pounds per square inch or less. The tangled fabric was then dried using a drying can (at a temperature of 250 ° F.) to reach a maximum temperature of 200 ° F. The basis weight of the resulting fabric was 125 grams per square meter.

Once formed, the antibiotic activity of each fabric sample was determined by ASTM No. E2149-01 (title "Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions"). The properties of the samples are shown in Table II below.

Characteristics of the sample Sample Added AEM 5772 (72% solids) (pounds) AEM 5772 pulp addition amount ([AEM solid weight / pulp weight] x 100%) AEM 5772 Fabric Addition ([AEM Solids Weight / Fabric Weight] × 100%) Bacteria Reduction (%) Creping One 8.3 0.30 0.23 > 97 none 2 8.3 0.30 0.23 > 97 has exist

Thus, as the results in Table II show, it is possible to provide fabrics with relatively high bacterial mortality, such as greater than 97%.

In addition, samples of AEM 5772 treated pulp slurry were taken from the pulp, machine chest, headbox and post-tangle white water silos to determine the amount of AEM 5772 depleted from the water-pulp slurry during pulp preparation. The pulp slurry was dewatered and the captured water samples were tested by an active quaternary titration method using sodium lauryl sulfate, chloroform, dye and buffer, respectively. No AEM 5772 quaternary silicon was detected in the collected water.

While the invention has been described in detail with reference to specific embodiments, it will be understood by those skilled in the art that modifications, variations, and equivalents to these embodiments can be readily understood by understanding the foregoing. Accordingly, the scope of the invention should be assessed as that of the appended claims and any equivalents thereto.

Claims (36)

Forming a solution from the liquid and the antibiotic; Combining a cellulosic fibrous material with the solution to form a liquid suspension, wherein the antibiotic is present in the cellulosic fibrous material after combining with the cellulosic fibrous material; And Forming a web from said liquid suspension of antibiotic treated cellulosic fibrous material such that substantially all of the cellulosic fibrous material present in the web is derived from an antibiotic treated cellulosic fibrous material A method of forming an antibiotic treated fabric comprising a. The method of claim 1, wherein at least a portion of the liquid is removed from the liquid suspension during formation of the web and the removed liquid portion is substantially free of the antibiotic. The method of claim 1 wherein the antibiotic is an organosilicon quaternary ammonium compound. The method of claim 3, wherein the organosilicon quaternary ammonium compound has the following structure. Where R ₁ is hydrogen or a C ₁ -C ₈ alkyl group; R ₂ is hydrogen or a C ₁ -C ₈ alkyl group; R ₃ and R ₄ are the same or different and are selected from the group consisting of hydrogen and C ₁ -C ₄ alkyl groups; R ₅ is hydrogen or a C ₁ -C ₃₀ alkyl group; X ⁻ is a suitable counter ion. The method of claim 1, wherein the antibiotic is 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride. The method of claim 1, wherein the antibiotic is hydrolyzed prior to forming the solution. The method of claim 1 wherein the solution and the cellulosic fibrous material are combined in a pulp. 8. The method of claim 7, wherein the solution and the cellulosic fibrous material are stirred while in the pulp. The method of claim 1, wherein the antibiotic is present in an amount from about 0.04 to about 1.0 weight percent of the antibiotic treated cellulosic fibrous material. The method of claim 1, wherein the antibiotic is present in an amount of about 0.2 to about 0.5 weight percent of the antibiotic treated cellulosic fibrous material. The method of claim 1 wherein the cellulosic fibrous material comprises high average length pulp fibers, low average length pulp fibers, or mixtures thereof. The method of claim 1, further comprising entangled the web of antibiotic treated fibrous material with a nonwoven substrate. The method of claim 12, wherein the nonwoven substrate is formed from continuous filaments. The method of claim 13, wherein the continuous filament is formed by a spunbond process. The method of claim 1, further comprising drying the web such that the antibiotic forms a covalent bond with the cellulosic fibrous material. The method of claim 15, wherein the antibiotic is an organosilicon compound such that the covalent bond is a siloxane bond. Forming a solution from a liquid, and an antibiotic that is an organosilicon quaternary ammonium compound; Agitating pulp fibers with the solution to form a liquid suspension, wherein the organosilicon quaternary ammonium compound is present in the pulp fibers after combining with the pulp fibers; Forming a web from said liquid suspension of antibiotic treated cellulosic fibrous material such that substantially all of the cellulosic fibrous material present in the web is derived from an antibiotic treated cellulosic fibrous material; Entangle the web of antibiotic treated pulp fibers with a nonwoven substrate; And Drying the web such that the antibiotic forms a covalent bond with pulp fibers A method of forming an antibiotic treated fabric comprising a. 18. The method of claim 17, wherein said covalent bond is a siloxane bond. 18. The method of claim 17, wherein at least a portion of the liquid is removed from the liquid suspension during formation of the web, wherein the removed liquid portion is substantially free of the antibiotic. 18. The method of claim 17, wherein the organosilicon quaternary ammonium compound has the following structure. Where R ₁ is hydrogen or a C ₁ -C ₈ alkyl group; R ₂ is hydrogen or a C ₁ -C ₈ alkyl group; R ₃ and R ₄ are the same or different and are selected from the group consisting of hydrogen and C ₁ -C ₄ alkyl groups; R ₅ is hydrogen or a C ₁ -C ₃₀ alkyl group; X ⁻ is a suitable counter ion. 18. The method of claim 17, wherein the antibiotic is 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride. 18. The method of claim 17, wherein the solution and the pulp fibers are combined in pulper. 18. The method of claim 17, wherein the nonwoven substrate is formed from continuous filaments. The method of claim 23, wherein the continuous filament is formed by a spunbond process. An antibiotic treated composite fabric comprising a pulp fiber and a nonwoven continuous filament substrate entangled, wherein substantially all pulp fibers present in the composite material are treated with an organosilicon antibiotic. 27. The antibiotic treated composite fabric of claim 25 wherein the antibiotic is an organosilicon quaternary ammonium compound. 27. The antibiotic treated composite fabric of claim 25 wherein the organosilicon quaternary ammonium compound has the following structure. Where R ₁ is hydrogen or a C ₁ -C ₈ alkyl group; R ₂ is hydrogen or a C ₁ -C ₈ alkyl group; R ₃ and R ₄ are the same or different and are selected from the group consisting of hydrogen and C ₁ -C ₄ alkyl groups; R ₅ is hydrogen or a C ₁ -C ₃₀ alkyl group; X ⁻ is a suitable counter ion. 27. The antibiotic treated composite fabric of claim 25 wherein the antibiotic is 3- (trimethoxysilyl) propyloctadecyldimethyl ammonium chloride. 27. The antibiotic treated composite fabric of claim 25, wherein said organosilicon antibiotic comprises about 0.04 to about 1.0 weight percent of said pulp fibers. 27. The antibiotic treated composite fabric of claim 25, wherein said organosilicon antibiotic comprises about 0.2 to about 0.5 weight percent of said pulp fibers. 27. The antibiotic treated composite fabric of claim 25 wherein the continuous filaments are formed by a spunbond process. 27. The antibiotic treated composite fabric of claim 25, wherein the pulp fibers comprise about 60 to about 90 weight percent of the composite fabric. 27. The antibiotic treated composite fabric of claim 25, wherein said organosilicon antibiotic comprises about 0.03 to about 0.8 weight percent of said composite fabric. 27. The antibiotic treated composite fabric of claim 25, wherein said organosilicon antibiotic comprises from about 0.16 to about 0.4 weight percent of said composite fabric. 27. The antibiotic treated composite fabric of claim 25 wherein said organosilicon antibiotic is covalently bonded to said pulp fibers. 38. The antibiotic treated composite fabric of claim 35 wherein the covalent bond formed between the organosilicon antibiotic and the pulp fiber is a siloxane bond.