Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
  • D06M15/01—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with natural macromolecular compounds or derivatives thereof
  • D06M15/03—Polysaccharides or derivatives thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/42—Use of materials characterised by their function or physical properties
  • A61L15/44—Medicaments
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
  • A61L15/26—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
  • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
  • A61L15/42—Use of materials characterised by their function or physical properties
  • A61L15/46—Deodorants or malodour counteractants, e.g. to inhibit the formation of ammonia or bacteria
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
  • A61L2300/10—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices containing or releasing inorganic materials
  • A61L2300/102—Metals or metal compounds, e.g. salts such as bicarbonates, carbonates, oxides, zeolites, silicates
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
  • A61L2300/10—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices containing or releasing inorganic materials
  • A61L2300/102—Metals or metal compounds, e.g. salts such as bicarbonates, carbonates, oxides, zeolites, silicates
  • A61L2300/104—Silver, e.g. silver sulfadiazine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
  • A61L2300/20—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices containing or releasing organic materials
  • A61L2300/23—Carbohydrates
  • A61L2300/232—Monosaccharides, disaccharides, polysaccharides, lipopolysaccharides
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
  • A61L2300/40—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices characterised by a specific therapeutic activity or mode of action
  • A61L2300/404—Biocides, antimicrobial agents, antiseptic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
  • A61L2300/40—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices characterised by a specific therapeutic activity or mode of action
  • A61L2300/45—Mixtures of two or more drugs, e.g. synergistic mixtures

Definitions

• This invention relates to antimicrobial polyester-containing articles and methodology for the preparation of antimicrobial polyester-containing articles utilizing chitosan and chitosan - metal complexes as the antimicrobial agent.
• This invention relates to the use of chitosan and chitosan - metal complexes to generate polyester-containing articles having antimicrobial properties.
• PCT application WO 00/49219 discloses the preparation of substrates with biocidal properties. The deposition of solubilized chitosan on polyester, among other materials, followed by treatment with silver salts, reduction of the silver salt and crosslinking the chitosan is disclosed to yield a durable biocidal article. The application also discloses the crosslinking of the chitosan after it is applied, either before or after the silver salt treatment.
• JP Kokai H9-291478 discloses a process for the application of a chitosan derivative to polyester fabric comprising UV treatment of the polyester fabric followed by application of a chitosan-derived quaternary ammonium base.
• the UV irradiation serves to generate free radicals on the surface of the polyester fabric to which the chitosan is subsequently attached.
• H. Shin et al, Sen-I Gakkaishi, 54(8), 400-406 discloses similar UV fabric treatment and also a low temperature air plasma treatment prior to chitosan treatment.
• JP Kokai H8-22772 discloses a process for the manufacture of an antibacterial acrylic yarn which comprises dipping, in an aqueous acidic chitosan solution, a wet spun yarn from an acrylonitrile-based polymer solution, neutralizing with an aqueous alkali solution, drying and densifying. The process may be carried out batch-wise or continuously.
• the chitosan is absorbed on the surface of the yarn and deposited in micro-voids within the yarn before drying.
• S. Matsukawa et al., Sen-I Gakkaishi, 51 (1), 51-56 (1995) disclose the modification of polyester fabrics using chitosan. The polyester was hydrolyzed with caustic soda, neutralized with 1 % acetic acid solution, then treated with a chitosan solution and, optionally, with a crosslinking agent.
• This invention provides an antimicrobial polyester-containing article having chitosan grafted onto the article and optionally, containing one or more metal salts, one or more carboxyl-containing polymers or combination thereof.
• a process for preparing antimicrobial polyester- containing articles comprising the sequential steps of: (a) providing a polyester-containing article; (b) contacting the polyester-containing article with a basic solution;
• step (c) optionally, washing the article produced in step (b);
• step (d) contacting the article produced in step (b) or step (c) with a strong mineral acid solution;
• step (e) optionally, washing the article produced in step (d);
• step (f) contacting the article produced in step (d) or step (e) with a solution comprising a chitosan agent selected from the group consisting of chitosan, chitosan salts and chistosan derivatives;
• a chitosan agent selected from the group consisting of chitosan, chitosan salts and chistosan derivatives
• step (i) optionally, heating the article isolated in step (h) at a temperature higher than the temperature of step (g).
• step (d) drawing the step (b)- or step (c)-treated article through a third treatment station wherein the article is exposed to a strong mineral acid solution;
• step (e) optionally, drawing the step (d)-treated article through a fourth treatment station wherein the article is exposed to deionized water;
• step (f) drawing the step (d)- or step (e)-treated article through a fifth treatment station wherein the article is exposed to a solution comprising a chitosan agent;
• step (g) optionally, heating the step (f)-treated article after it exits the chitosan treatment station;
• step (h) causing the step (f)- or step (g)-treated article to be received on and accumulate on the take-up station.
• Figure 1 is a diagram showing the antimicrobial effect of chitosan grafted on 3GT knit fabric vs. Listeria monocytogenes ATCC 15313.
• Figure 2 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Klebsiella pneumoniae ATCC 4352.
• Figure 3 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Candida albicans ATCC 10231.
• Figure 4 is a diagram showing the antimicrobial effect of chitosan grafted on 3GT woven fabric vs. Staphylococcus aureus ATCC 6538.
• Figure 5 is a diagram showing the antimicrobial effect of chitosans of various molecular weights grafted onto 2GT woven microfiber fabric vs. E. coll ATCC 25922.
• Figure 6 is a diagram showing the antimicrobial effect of chitosans of various molecular weights grafted onto 2GT woven microfiber fabric vs. Staphylococcus aureus ATCC 29213.
• Figure 7 is a diagram showing the antimicrobial effect of chitosan grafted onto 3GT fabrics with and without silver nitrate treatment vs. Salmonella cholerasuis ATCC 9239.
• Figure 8 is a diagram showing the antimicrobial effect of chitosan grafted on 3GT fabrics with and without copper sulfate treatment vs. E. coli 0157:H7.
• Figure 9 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fabrics with various concentration silver nitrate solution post treatment vs. Staphylococcus aureus ATCC 6538.
• Figure 10 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fabrics after various hydrolysis times with and without a 0.1 % silver nitrate post treatment vs. E. coli O157:H7.
• Figure 11 is a diagram showing the antimicrobial activity of free chitosan vs. grafted chitosan on 2GT fabric vs. Staphylococcus aureus ATCC 6538.
• Figure 12 is a diagram showing the antimicrobial activity of grafted chitosan on 2GT knit fabrics with various after-treatments of polyacrylic acid, additional chitosan and/or silver nitrate treatment vs. E. coli 25922.
• Figure 13 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fiber by processing in a package dyer vs. E. coli ATCC 25922.
• Figure 14 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fiber by processing in a package dyer and single-end sizer
• Figure 15 is a diagram showing the antimicrobial effect of a chitosan-treated polyester and Lycra® blend fiber vs. E. coli ATCC 25922.
• Figure 16 is a diagram showing the antimicrobial effect vs. E. coli ATCC 25922 of chitosan treatment of yarns commonly occurring in polyester blends.
• Figure 17 is a diagram showing the antimicrobial effect of a chitosan-treated polyester/rayon nonwoven fabric vs. E. coli ATCC 25922.
• Figure 18 is a diagram showing the antimicrobial effect of a chitosan-treated polyester/wood pulp nonwoven fabric vs. E. coli ATCC 25922.
• Figure 19 is a diagram showing the antimicrobial effect of a chitosan-treated bicomponent (2GT/3GT) polyester fiber vs. E. coli ATCC 25922.
• Figure 20 is a schematic diagram of the continuous process of the invention for making antimicrobial polyester-containing articles. DETAILED DESCRIPTION OF THE INVENTION The present invention involves the preparation of antimicrobial polyester-containing articles that have chitosan grafted thereon. Chitosan is the commonly used name for poly- [1-4] ⁇ -D-glucosamine.
• Chitosan is chemically derived from chitin, which is a poly- [1 -4]- ⁇ -N-acetyl-D- glucosamine which, in turn, is derived from the cell walls of fungi, the shells of insects and, especially, crustaceans.
• grafted means that the chitosan is bound to the polyester substrate by either ionic (electrostatic) or covalent bonding. Grafting of the chitosan to the polyester article may be confirmed by Electron Spectroscopy for Chemical Analysis (ESCA) [see, for example, Xin Qu, Anders Wirsen, Bjorn Orlander, Anne-Christine Albertsson, Polymer Bulletin, (2001), vol.
• ESA Electron Spectroscopy for Chemical Analysis
• ESCA data demonstrate that the chitosan-modified surfaces of the polyester-containing articles of the present invention are similar in composition to those of the chitosan starting materials.
• the ESCA data also show that these surfaces have a significant level of nitrogen that is incorporated in a salt form, which provides evidence that the chitosan in physically linked to the surface through ionic interactions.
• Polyesters comprise those polymers prepared from diols and dicarboxylic acids.
• Dicarboxylic acids useable in the preparation of polyesters include, but are not limited to, unsubstituted and substituted aromatic, aliphatic, unsaturated, and alicyclic dicarboxylic acids and the lower alkyl esters of dicarboxylic acids having from 2 carbons to 36 carbons.
• the desirable dicarboxylic acid component include terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-napthalene dicarboxylic acid, dimethyl-2,6-naphthalate, 2,7-naphthalenedicarboxylic acid, dimethyl-2,7-naphthalate, 3,4'-diphenyl ether dicarboxylic acid, dimethyl-3,4'diphenyl ether dicarboxylate, 4,4'- diphenyl ether dicarboxylic acid, dimethyl-4,4'-diphenyl ether dicarboxylate, 3,4'-diphenyl sulfide dicarboxylic acid, dimethyl-3,4'- diphenyl sulfide dicarboxylate, 4,4'-diphenyl sulfide dicarboxylic acid, dimethyl-4,4'-diphenyl sulfide dicarboxylate, 3,4'-diphenyl s
• Diols useful in the preparation of polyesters include, but are not limited to, unsubstituted, substituted, straight chain, branched, cyclic aliphatic, aliphatic-aromatic or aromatic diols having from 2 carbon atoms to 36 carbon atoms.
• the desirable diol component include ethylene glycol, 1,3-propanediol, 1 ,2-propanediol, 1 ,2-, 1 ,3- and 1 ,4-butanediol, 1 ,5-pentane diol, 1 ,6-hexanediol, 1 ,8-octanediol, 1 ,10- decanediol, 1 ,12-dodecanediol, 1 ,14-tetradecanediol, 1 ,16- hexadecanediol, dimer diol, isosorbide, 4,8-bis (hydroxymethyl)-tricyclo [5.2.1.0/2.6]decane, 1 ,2-, 1 ,3- and 1 ,4-cyclohexanedimethanol, and the longer chain diols and polyols made by the reaction product of diols or polyols with alky
• polyesters useful herein are poly(ethylene terephthalate) (“2GT”), polyttrimethylene terephthalate) (“3GT”), and blends and copolymers thereof.
• polyester-containing article means an article that has a surface composition of at least 10% polyester by area.
• garments comprising polyester often include other components, such as acrylic, wool, silk, cotton, linen, flax, hemp, rayon, cellulose, wood pulp, cellulose acetate or triacetate, nylon 6 or nylon 66, poly(m-phenylene isophthalamide) ('PMIA,' available from E. I. du Pont de Nemours and Company, Wilmington, DE, USA under the trademark Nomex®), poly(p-phenylene terephthalamide) ('PPTA ,' available from E. I.
• polyesters other than poly(ethylene terephthalate) may also be present, for example, a copolymer with a low melt temperature that is used as a binder fiber in fiberfill.
• Fibers listed above can be used in the present invention for added benefits.
• Such fiber combinations can be prepared by any means known to those skilled in the art.
• "Bicomponent" filaments in which two polymers are arranged side-by-side or in a sheath-core arrangement can be formed during the spinning process.
• 2GT/3GT bicomponent fibers such as are disclosed in U.S. Patent 3,671 ,379, herein incorporated by reference, are one example useful in the present invention.
• Fiber combinations can also be prepared by knitting or weaving yarns, staple, or filament of different composition into the same fabric.
• Lycra® spandex E. I. de Nemours and Company, Wilmington, DE
• the spandex is added in staple yarn at either the spinning step or during fabric production, such as plating in knitting.
• polyester- containing articles are pretreated.
• This pretreatment involves hydrolyzing the surface of said polyester-containing article to prepare it for subsequent attachment of chitosan groups.
• the pretreatment is achieved by the hydrolytic rupture of some of the ester bonds in the polyester-containing articles to generate carboxylate groups.
• the hydrolysis treatment involves exposure of the polyester- containing article to an aqueous solution of a base. All soluble Group I, II, and III hydroxides, ammonium hydroxide, and alkyl-substituted ammonium hydroxides can be used to effect hydrolysis.
• the base can be dissolved in water or a mixture of water with one or more water-soluble organic solvents.
• Suitable water-soluble organic solvents include methanol, ethanol, propanol, ethylene glycol, propylene glycol, acetonitrile, dimethylformamide, and dimethylacetamide.
• the base useful in the invention is typically an alkali metal hydroxide, most preferably sodium hydroxide.
• the concentration of base in the aqueous solution is not critical and depends on the base being used and the treatment temperature. In the case of sodium hydroxide, the concentration may range from 1 to 40% by weight.
• the temperature of the treatment is not critical, room temperature being preferred.
• Temperature ranges of 10 to 90°C may be employed. Lower temperature is preferred with the higher concentrations of base.
• the article is exposed to the basic solution long enough to reduce its weight by from 1 to 30 percent, preferably by from 1 to 10 percent.
• the treatment time will depend on the concentration and temperature of the basic solution; the higher the concentration of the base solution, and the higher the temperature employed the shorter the time of treatment. Times as low as 2 to 30 seconds can be employed successfully.
• the article is then washed with water to remove the bulk of the base solution.
• the article is acidified by treatment with strong mineral acid to a pH of less than or equal to the pKa of the carboxylate groups generated by the hydrolysis treatment.
• the article can be directly acidified with aqueous mineral or organic acids without the involvement of water washing. However, aqueous washing is preferred to minimize the use of acids.
• strong mineral acid means acids having a pH less than pH 2.
• Mineral acids useful herein include, for example, hydrochloric, sulfuric and phosphoric acids. Hydrochloric acid is most preferred.
• the time and temperature of the acidification step are not critical; times ranging from 2 seconds to 30 minutes at room temperature can be employed successfully.
• the article is again washed with water to remove the bulk of the mineral acid.
• the article may then be used directly in the next step, or may, optionally, be dried.
• the acidification below the pKa of the carboxylate groups greatly increases the rate and efficacy of the reaction of the carboxyl species with chitosan in the subsequent step.
• the article is treated with chitosan. This comprises soaking or wetting the article with a solution containing a chitosan agent.
• chitosan agent as used herein means all chitosan-based moieties, including chitosan, chitosan salt, and chitosan derivatives.
• the solution comprising the chitosan agent may be aqueous.
• chitosan since chitosan by itself is not soluble in water, the chitosan may be solubilized in a solution. Solubility is obtained by adding the chitosan to a dilute solution of a water-soluble, organic acid selected from the group consisting of mono-, di- and polycarboxylic acids. This allows the chitosan to react with the acid to form a water-soluble salt, herein referred to as "chitosan salt.”
• chitosan derivatives including N- and O-carboxyalkyl chitosan, that are water-soluble, can be used directly in water instead of chitosan salt. .
• the chitosan may also be dissolved in special solvents like dimethylacetamide in the presence of lithium chloride, or N-methyl-morpholine-N-oxide.
• solubilized chitosan solutions can be used in the present invention instead of aqueous solutions containing chitosan salt or chitosan derivatives.
• the chitosan solution is an aqueous acetic acid solution, for example, an aqueous solution containing 2% chitosan and 0.75% acetic acid or 2% chitosan and 1.5% aqueous acetic acid.
• the time of treatment is typically 5 to 30 minutes.
• the temperature of the treatment is not critical, room temperature being preferred.
• excess solution may be allowed to drip out, or may be removed by wringing or spinning.
• the treated article is then dried via oven drying or a combination of ambient air drying and oven drying.
• Articles prepared by the above methods exhibit antimicrobial properties.
• antimicrobial as used herein, means both bactericidal and fungicidal.
• the fibers and yarns processed herein exhibit favorable physical properties with respect to tenacity, elongation and hand-feel.
• Said antimicrobial properties may, optionally, be further enhanced by treatment with soluble metal salts, for example, soluble silver salts, soluble copper salts and soluble zinc salts.
• soluble metal salts for example, soluble silver salts, soluble copper salts and soluble zinc salts.
• the preferred metal salts of the invention are aqueous solutions of zinc sulfate, copper sulfate or silver nitrate.
• the metal salts are typically applied by dipping or padding a dilute (0.1 to 5 %) solution of salt in water.
• the degree of enhancement depends on the particular metal salt used, its concentration, the time and temperature of exposure, and the specific chitosan treatment, that is, the type of chitosan agent, its concentration, the temperature, and the time of exposure. Examples 3, 4, 5, 6 and 7; Figures 7, 8, 9, 10 and 11 ; and Table 1 demonstrate the effect of metal salts in the process of the invention.
• Antistatic properties refer to the ability of a textile material to disperse an electrostatic charge and to prevent the buildup of static electricity. (Dictionary of Fiber & Textile Technology, Hoechst Celanese Corp., Charlotte, NC (1990), p.8)
• a further optional post-treatment comprises applying a carboxyl- containing polymer to the chitosan treated article, or to the metal salt treated chitosan treated article.
• carboxyl-containing polymer as used herein means a polymer that contains carboxylic acid groups in side chains attached to the polymer backbone.
• the carboxyl-containing polymer most preferably polyacrylic acid, is typically applied from a dilute aqueous solution by dipping or padding.
• any of the above described chitosan-treated articles, metal salt- treated articles or the carboxyl-containing polymer-treated articles, may benefit from a further chitosan solution treatment.
• articles that, having received a first treatment with chitosan by the process of the present invention, are further subjected to one or more treatments with metal salt, carboxyl-containing polymer and/or additional chitosan in any order, with the proviso that the surface of the final article is treated with metal salt or a chitosan solution.
• the process of the invention further involves heating the chitosan-grafted polyester-containing article to a temperature of from 35°C to 190°C under a nitrogen or ambient atmosphere for from 30 seconds to 20 hours, washing with deionized water and further drying the article at a temperature of 35°C to 190°C for from 30 seconds to 20 hours.
• a feed station (2) on which is disposed a polyester-containing article (1) is provided.
• the feed station would typically comprise one or more feed rollers (10).
• the article is drawn from the feed station through a first treatment station (4) wherein said article is exposed to a basic solution.
• the treatment stations herein would typically be immersion bath trays or tanks.
• the article is optionally drawn from the first treatment station through a second treatment station (5) wherein the step (b)-treated article is exposed to water.
• draw rolls (11) may help guide the article between the treatment stations. Draw rolls such as draw roll (11) may be placed along any step of the continuous process as is commonly known in the art.
• the article from the third treatment station is drawn through a fourth treatment station (7) wherein the step (d)-treated article is exposed to water.
• step (f) The article is then drawn through a fifth treatment station (8) wherein the step (d)- or step (e)-treated article is exposed to a solution comprising the chitosan agent.
• the chitosan agent is selected from the group consisting of chitosan, chitosan salts and chitosan derivatives.
• the treatment stations would typically be immersion bath trays or tanks.
• the step (f)-treated article is heated by a heater, such as a heater roll assembly (9) after it exits the chitosan treatment station.
• a heater such as a heater roll assembly (9)
• the step (f)- or step (g)-treated article is then received on and accumulates on the take-up station (3).
• the treated article would typically be wound by means of a traversing guide (12) onto the take- up station (3) which is typically one or more cardboard or resin tubes to form spinning bobbins.
• the feed station, treatment stations, heaters, and take-up components may be any convenient means known in the art for continuous treatment of fibers and yarns (see, for example, Ullmann's Encyclopedia of Industrial Chemistry, fifth Edtion, Wolfgang Gerhartz, Executive Editor, Volume A10, VCH Verlagsgesellschaftg, Weinheim, Federal Republic of Germany (1987), "Fibers, 3. General Production Technology,” H. Lucker, W. Kagi, U. Kemp, and W. Stibal, pp. 511-566).
• the continuous process is particularly appropriate for treating polyester- containing fiber or yarn on a commercial scale.
• the process and articles of the present invention do not employ crosslinking agents which makes the process more efficient and economical than other currently available processes requiring the use of crosslinking agents.
• crosslinking agent connotes the commonly used di- or tri-functional crosslinking agents known in the art.
• carboxyl-containing polymers e.g. polyacrylic acids, are not construed to be crosslinking agents in the context of the present invention.
• the preferred articles of the present invention are in the form of fibers; fabrics, including wovens and nonwovens; filaments; films; and articles and constructs prepared therefrom.
• the antimicrobial articles of the invention shall find application in uses such as apparel, including sportswear, activewear, intimate apparel, swimwear and medical garments; healthcare, including medical drapes, antimicrobial wipes, surfaces (counters, floors, walls), personal hygiene products and medical packaging; household articles, including fiberfill, bedding, window treatments and surfaces; and food processing/service, including packaging, absorbent antimicrobial pads for meat packaging, antimicrobial wipes and surfaces.
• Fiber-based materials were used in the following Examples. Woven and knit fabrics were also tested as outlined in the Examples. 1. Poly(ethylene terephthalate) (“2GT”) fiber, knit fabric and microfiber woven fabric, from E. I. du Pont de Nemours and Company (Wilmington, DE). 2. Sorona® poly(trimethylene terephthalate) (“3GT”) yarn, 70 denier, 34 filament, round cross-section, made by E. I. du Pont de Nemours and Company (Wilmington, DE).
• 2GT Poly(ethylene terephthalate)
• 3GT Sorona® poly(trimethylene terephthalate)
• chitosan materials used in this study were obtained as commercially available from Primex Ingredients ASA, Norway under the trademark Chitoclear® chitosan and were used as purchased.
• Treated articles were tested for antimicrobial properties by the Shake Flask Test for Antimicrobial Testing of Materials, as follows: 1. A single, isolated colony from a bacterial or yeast agar plate culture was inoculated in 15-25 ml of Trypticase Soy Broth (TSB) in a sterile flask. It was incubated at 25-37°C (using optimal growth temperature for the specific microbe) for 16-24 hours with or without shaking (selecting appropriate aeration of the specific strain). For filamentous fungi, sporulating cultures were prepared on agar plates.
• TTB Trypticase Soy Broth
• the overnight bacterial or yeast culture was diluted into sterile phosphate buffer (see below) at pH 6.0 to 7.0 to obtain approximately 10 5 colony forming units per ml (cfu/ml).
• the total volume of phosphate buffer needed was 50 ml x number of test flasks (including controls).
• spore suspensions at 10 5 spores/ml were prepared. Spore suspensions were prepared by gently resuspending spores from an agar plate culture that had been flooded with sterile saline or phosphate buffer.
• TSA Trypticase Soy Agar
• Stock phosphate buffer
• Deionized Water volume increased to 1000 ml
• the pH of the phosphate buffer was adjusted to pH 6.0 to 7.0 with either NaOH or HCI.
• the stock phosphate buffer was filtered, sterilized, and stored at 4°C until use.
• the working phosphate buffer was prepared by diluting 1 ml of stock phosphate buffer in 800 ml of sterile deionized water.
• Example 1 The chitosan used in Example 1 was food grade Chitoclear® chitosan (Primex Ingredients ASA, Norway). The degree of N-deacetylation of this sample was over 90% and this was ascertained by proton and carbon 13 NMR spectroscopy. The molecular weight of this sample was estimated using standard relative viscosity measurements as reported in the literature. The excess chitosan was allowed to drip, air dried for an hour and then dried at 85°C for 16 h under nitrogen atmosphere. The weights of the chitosan-grafted fabrics were: 3GT, 24.06 g; 2GT, 21.32 g.
• Figure 1 shows the antimicrobial effect of chitosan grafted on 3GT knit fabric vs. Listeria monocytogenes ATCC 15313; the 3GT control is untreated fabric.
• Figure 2 shows the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Klebsiella pneumoniae ATCC 4352; the 2GT control is untreated fabric.
• Figure 3 shows the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Candida albicans ATCC 10231.
• Figure 4 shows the antimicrobial effect of chitosan grafted on 3GT woven fabric vs. Staphylococcus aureus ATCC 6538.
• Chitosan grafted onto 2GT and 3GT polyester fabrics demonstrated at least a 3-log reduction of the following microorganisms in 4-6 h: Escherichia coli ATCC 25922
• Escherichia coli ATCC 49106 enteroxigenic/enterohemorrhagic
• chitosan grafted 3GT knit fabric (23.1 g), prepared according to the procedure of Example 1 was treated with 2% copper sulfate solution as described above to obtained copper doped fabric, (23.7 g).
• metal doping of chitosan- grafted polyester may be used to enhance antimicrobial activity.
• Silver nitrate ( Figure 7), copper sulfate ( Figure 8) or, by a similar procedure, zinc sulfate were used successfully as metal dopes.
• Figure 7 demonstrates 3GT fabrics prepared with grafted chitosan with or without a silver nitrate dope vs. Salmonella cholerasuis ATCC 9239.
• Figure 8 demonstrates 3GT fabrics prepared with grafted chitosan with or without a copper sulfate dope vs. E. co// 0157:H7.
• Escherichia coli ATCC 49106 enterothelial cells
• Escherichia co/7 ' O157:H7 enterohemorrhagic
• EXAMPLE 4 Preparation of chitosan grafted fabrics after treated with various concentrations of silver nitrate solution 2GT knit fabrics in the form of (five) socks were soaked in water, the excess water drained, and then treated with 40% aqueous sodium hydroxide for 2 min. These socks were then extensively washed with water and soaked in 1M aqueous hydrochloric acid for 2 min, then washed with water. This was followed by immersing the socks in aqueous 1% chitosan (Chitoclear®, food grade, mol. wt.
• Figure 11 shows the antimicrobial activity of free chitosan, grafted chitosan and silver nitrate-treated grafted chitosan vs. Staphylococcus aureus ATCC 6538.
• Free chitosan demonstrates lower antimicrobial activity, which is more characteristic of a bacteriostat, compared to chitosan grafted onto polyester with or without silver nitrate post treatment.
• Multi-layer grafting of 2GT fabrics with chitosan and polyacrylic acid Four 2GT knit fabrics (samples A-D, 19.5, 18.8, 19.5, 19.7 g, respectively) were grafted with chitosan as described in Example 1. Weight of the products A-D were 21.3, 20.4, 21.2, and 21.1 g, respectively.
• Fabric samples A and B were dipped in 2% polyacrylic acid solution for 30 min, air dried and washed with water and then dried at 80°C to give chitosan polyacrylic acid coated fabrics A' (21.5 g) and B' (20.6 g).
• Part of fabric A' (10.3 g) was treated again with 2% chitosan solution and dried at 85° C for 16 h followed by washing with water and dried to give A"(10.5 g).
• Another part of A' (11.2 g) was dipped in 2% silver nitrate solution for 30 min, washed with water and dried at 37°C for 16 h. to give A'".
• Weight of A'" was 11.02 g.
• Figure 12 shows the antimicrobial activity of 2GT + chitosan (A); 2GT + chitosan + polyacrylic acid (A”); 2GT + chitosan + polyacrylic acid + chitosan (A"), and 2GT + chitosan + polyacrylic acid;+ silver nitrate (A'”) and three various controls vs. E. coli 25922.
• the chitosan chemistry described in the above examples can be applied to fibers as well as fabrics using standard fiber processing equipment.
• the preparation of antimicrobial fibers by performing the caustic hydrolysis, acidification, and chitosan grafting steps in a package dyer, as well as by performing the caustic hydrolysis and acidification in a package dyer and the chitosan grafting step in a single-end sizer machine has been demonstrated.
• Figure 13 shows antimicrobial performance of 2GT fiber with grafted chitosan applied by processing in a package dyer vs. E. coli ATCC 25922.
• Figure 14 shows the antimicrobial performance of 2GT fiber with grafted chitosan applied by processing in a package dyer and single-end sizer vs. E. coli ATCC 25922.
• Fibers of a Lycra® spandex/2GT blend (Lycra® spandex/2GT blend fiber containing 10% 10 denier Lycra® and 90% 150 denier Dacron® polyester, made by E. I. du Pont de Nemours and Company (Wilmington, DE)) were treated with caustic as described in Example 1. The treated fibers were then passed through a chitosan solution in a single-end sizer as in Example 9. Figure 15 shows the antimicrobial effect of the chitosan-treated fibers versus E. coli ATCC 25922.
• EXAMPLE 11 Chitosan treatment of yarns commonly combined with polyester in fabrics
• Cotton yarn having a yarn count of 30/1 cc, commercially available from Parkdale Mills, Inc. (Gastonia, NC)), Soft White® 24 acrylic yarn (1/24 worsted count with a 1 1/2" cut, 100% open end spun yarn that has been waxed, made by Amital Spinning Corporation (New Bern, NC)), and Tactel® nylon 66 (30 denier yarn (commercially available from E. I. du Pont de Nemours and Company, Wilmington, DE) were treated with caustic as described in Example 1. The treated fibers were then passed through a chitosan solution in a single end sizer as in Example 9.
• Figure 16 shows the antimicrobial effect of the chitosan-treated yarns versus E. coli ATCC 25922.
• Sontara® wipes comprising a 1 :1 polyester/rayon nonwoven blend (commercially available from E. I. du Pont de Nemours and Company. (Wilmington, DE) were treated as in Example 1 , one sample with only the caustic treatment described therein and one with the complete chitosan grafting treatment.
• the antimicrobial effect of the chitosan grafting treatment versus E coli ATCC 25922 is seen in Figure 17.
• EXAMPLE 13 Chitosan-treated polyester/cellulose nonwoven fabric Sontara® wipes comprising a 1 :1 polyester/wood pulp nonwoven blend (commercially available from E. I. du Pont de Nemours and Company, Wilmington, DE) were treated as in Example 1 , one sample with only the caustic treatment described therein and one with the complete chitosan grafting treatment.
• the antimicrobial effect of the chitosan grafting treatment versus E coli ATCC 25922 is seen in Figure 18.
• EXAMPLE 14-18 (a) Preparation of surface primed 2GT fibers 2GTfiber (150-200 g, 229 g) was passed at a rate of about 8 m/min through a series of solution trays containing, in turn, 10% aqueous sodium hydroxide, 1.0 M aqueous hydrochloric acid, and water. Excess solution was then stripped from the fiber with a sponge. The fiber was then dried by wrapping around a drum heated to about 130°C. The fiber was then wound using a tension winder followed by heat setting the fiber at 160°C by wrapping around a heated roller at that temperature and winding at a speed at 60 m/min. Yield of the fiber was 218.7 g, a loss of 4.5 weight percent. This procedure demonstrates the hydrolysis conditions that cause weight loss of the fiber. The process resulted in the formation of carboxyl groups on the surface of the fiber as evidenced from the dying of the fiber with a blue dye specific for acidic groups.
• 2GT fiber 150-200 g was passed at a rate of about 8 m/min through a series of solution trays containing, in turn, 10% aqueous sodium hydroxide, 1.0 M aqueous hydrochloric acid, water, and a solution of chitosan (Chitoclear®, Primex Ingredients, Norway) in 1% aqueous acetic acid.
• concentration of chitosan varied from 0.25 to 2 weight percent, as shown in Table 1. Excess solution was then stripped from the fiber with a sponge. The fiber was dried by wrapping around a drum heated to about 130°C.
• the fiber was then wound using a tension winder followed by heat setting of the fiber at 160°C by wrapping around a heated roller at that temperature and winding at a speed at 60 m/min.
• the chitosan-treated fiber was tested with Orange II dye, and the orange color indicated chitosan was present on the surface of the fiber.
• a portion of fiber that had been treated with a 2% chitosan solution was made into a fabric and dyed with Orange II dye. The intense orange color indicated that chitosan was present at the surface of the fabric.
• EXAMPLE 20 Preparation of antimicrobial chitosan-2GT/3GT fibers 2GT/3GT bicomponent fiber from E. I. du Pont de Nemours and Company (Wilmington, DE) was passed at a rate of about 8 m/min through a series of solution trays containing, in turn, 10% aqueous sodium hydroxide, 1.0 M aqueous hydrochloric acid, water, and a solution of 0.25% chitosan (Chitoclear®, Primex Ingredients ASA, Norway) in 1 % aqueous acetic acid. This was followed by stripping the excess solution in the fiber with a sponge. The fiber was dried by wrapping around a drum heated to about 130°C.
• the fiber was then wound using a tension winder followed by heat setting of the fiber at 160°C by wrapping around a heated roller at that temperature and winding at a speed at 60 m/min. Two samples were taken from different part of the fiber and submitted for antimicrobial evaluation.
• the antimicrobial effect of the chitosan grafting treatment versus E coli ATCC 25922 is seen in Figure 19.

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