MXPA00008160A - Esterified triclosan derivatives as improved textile antimicrobial agents - Google Patents

Abstract

This invention relates to fabrics comprised of individual fibers within which esterified triclosan has been diffused. This process imparts long-lasting durable antimicrobial, germicidal, and fungicidal properties to textiles which has heretofore not been achieved with triclosan alone.This invention relates to fabrics comprised of individual fibers within which esterified triclosan has been diffused. This process imparts long-lasting durable antimicrobial, germicidal, and fungicidal properties to textiles which has heretofore not been achieved with triclosan alone.

Description

ESTRIFIED DERIVATIVES OF TRICLOSAN AS IMPROVED ANTIMICROBIAL AGENTS FOR TEXTILES TECHNICAL FIELD This invention relates to fabrics composed of individual fibers within which esterified triclosan has diffused. This process imparts long-lasting antimicrobial, germicidal and fungal properties in textiles, which until now have not been achieved with triclosan alone.

BACKGROUND OF THE INVENTION In recent years, great attention has been paid to the risks of antimicrobial contamination from potential daily exposure. Examples worth mentioning of this interest include the fatal consequences of food poisoning due to certain strains of Escherichia coli found in poorly cooked meats in fast food restaurants, contamination by Salmonella that cause diseases from food products. of poorly cooked or badly washed birds; and diseases and infections of the skin attributed to Staphylococcus aureus, yeasts and other unicellular organisms. With this growing consumer interest in this area, manufacturers have begun introducing antimicrobial agents such as triclosan, available from Ciba-Geigy, under the registered trademark Irgasan® into some household products. For example, certain brands of cutting boards made of polypropylene, liquid soaps, etc. all contain this highly effective antimicrobial compound. In general, the incorporation of triclosan from liquid or polymeric medium has been relatively simple. However, there is a great need to provide effective, durable antimicrobial characteristics in textiles, particularly clothing fabrics, which is extremely difficult to perform with triclosan. There are commercially available textile products containing acrylic and / or acetate fibers co-extruded with triclosan (for example Hoechst Celanese sells these acetate fabrics with the name Microsafe ™ and Courtaulds sells these acrylic polymeric fabrics under the name A icor ™). However, this application is limited to those types of fibers; does not work specifically for and within polyester, polyamide, cotton, lycra, etc. In addition, this co-extrusion process is very expensive, particularly when compared to the inventive process. Triclosan and its derivatives, as well as the antimicrobial properties possessed by these compounds, have been shown within U.S. Patent Nos. 3,506,720 and 3,904,696, both of Model et al., U.S. Patent No. 3,929,903 of Noguchi et al., And Swiss Patent 459,656 to Bindler et al., all of which are incorporated herein by reference. Surface treatments in textiles incorporating triclosan and triclosan derivatives have already been taught to impart temporary antimicrobial characteristics taught to impart temporary antimicrobial characteristics to clothing fabrics. Triclosan and its derivatives, and the dispersions thereof, are favorable textile treatment agents mainly because of their low toxicity to the skin, as well as their high levels of antimicrobial, germicidal, etc. activity. However, due to its high volatility at high temperatures, its high solubility in aqueous medium at high pH, triclosan tends to be easily washed from a fabric substrate after some laundry applications. Also, as already noted, the chlorine bleach easily reacts with triclosan thereby decreasing its antimicrobial capabilities. Textile treatments incorporating triclosan and its derivatives, including some esterified products, are described in U.S. Patent No. 3,753,914 to Berth et al., And Swiss Patent 450,347 to Bindler, both of which are incorporated in their entirety as a reference. . Neither of these patents teach nor do they suggest a process by which the triclosan ester diffuses specifically within the individual fibers of a fabric, thereby providing long-lasting bactericidal, fungal, germicidal, etc. effects on the fabric substrate. . The Swiss Patent describes impregnation in a cloth; however, such treatment is only a surface application that fills the interstices between the threads (as defined within the Dictionary of Fiber &Textile Technology). This difference between the prior art and the inventive process is particularly distinguishable since diffusion requires very high temperatures to fully effect the introduction of triclosan into each individual fiber. In addition, the amounts of triclosan and triclosan derivatives applied to the fabrics within the teachings of this reference are much lower for durability within normal washing operations. Thus, there is no teaching or suggestion that provides a long-lasting antimicrobial treatment for textile fabrics. As a result, there is still a need within the textile industry to provide an application of triclosan antimicrobial derivatives 0 to fabrics that is durable, difficult to remove through normal washing techniques, that is not susceptible to degradation antimicrobial with contact and reaction with chlorine bleach and allowing the triclosan based compound to maintain substantially all of its antimicrobial properties during application throughout the fabric.

DESCRIPTION OF THE INVENTION An object of the invention is to provide an improved, long-lasting antimicrobial finish for textile substrates. Another object of the invention is to provide a relatively inexpensive process during the manufacture and / or staining of fabrics to incorporate tri2closan [sic] esters into individual textile fabrics to impart durable, long-lasting gcidal, fungicidal and antimicrobial properties to fabrics. . Another object of the invention is to provide a fabric for the garment industry that preserves the antimicrobial compounds therein through at least 25 wash cycles (equivalent to one year with washing every two weeks). Yet another object of this invention is to provide an antimicrobial fabric for use in the food service industry, such as tablecloths, napkins and the like, and not necessarily within the garment industry. Accordingly, this invention relates to a method for imparting durable antimicrobial properties to a fabric, which consists of the sequential steps of: (a) providing at least one ester derivative of triclosan; and (b) contacting the ester derivative of triclosan with a textile at a temperature and for a period of time sufficient to effect diffusion of the triclosan ester derivative within the individual fabrics of the textile. In addition, this invention also relates to another, more specific method of imparting durable antimicrobial properties to a fabric, consisting of the sequential steps of: (a) providing an ester derivative of triclosan; (b) introducing the ester derivative of triclosan into a dyebath wherein the dyebath contains at least one textile dye; (c) introducing a textile into the dyebath; (d) shaking the dyebath and raising the temperature of the dyebath to a temperature, under normal dye bath pressure, and for a time sufficient to effect diffusion of the triclosan ester derivative and the dye within the fibers individual of the textile; and 0 (e) removing the treated fabric from the dyebath. Nowhere in the prior art have these specific methods been described or practiced using an ester derivative of triclosan. Preferably, before introduction into the dye bath, the triclosan ester is dispersed within an aqueous medium by the addition of a surfactant, such as Triton ™ X-301, manufactured by Union Carbide. The preferred dye bath is a component of a jet dyeing machine, such as the Hisaka jet dyeing machine. Any ester derivative of triclosan is contemplated within this invention. Particularly preferably, due to its ease of manufacture and its efficacy in providing antimicrobial properties to a fabric are triclosan acetate, triclosan propionate, triclosan benzoate, triclosan 4-nitrobenzoate and triclosan hexanoate. This list is only a sample of the preferred compounds of this invention and is not intended to limit its scope. Any standard dye, pigment or dye used within a textile jet dyeing process is also contemplated. The amount of dye or dye may need adjustment of the normal concentrations to compensate for the treatment of the added triclosan ester derivative. It is considered that the presence of the triclosan ester, which acts as a type of plasticizer within the dyebath, aids in the diffusion of the dye within the textile fibers in certain cases. The textile substrate can be made of woven, non-woven or knitted fabric and made of any natural or synthetic fiber. Examples of the fibers include, but are not limited to, cotton, polyester, polyamide, ramin, acetate, polyolefin, acrylic and lycra fibers or any of the mixtures thereof. Of these, polyester, polyamide, particularly nylon (6 or 6.6) and lycra and especially nylon and lycra mixes are preferred. Likewise, the particularly preferred textiles are knitted ones. The long-lasting antimicrobial characteristics are more evident in these preferred textile substrates. The process itself, as already noted, requires a sufficiently high temperature and duration of exposure to effect exhaust and subsequent diffusion of the triclosan ester within the individual fibers of the textile substrate. Preferred temperatures in this process range from about 80 ° -130 ° C, with more specific temperatures depending on the particular ester derivative being depleted and the particular textile fabric being treated. For example, triclosan acetate diffuses well at a temperature of about 120 ° C within knitted polyester fibers, as well as knitted nylon and lycra blends. If the temperature is very low, the diffusion is not carried out. The necessary time generally is in the range from about 10 to about 120 minutes, again depending on the ester derivative being diffused and the fabric being treated. Again, just as an example, triclosan acetate requires approximately 20 minutes at 120 ° C to diffuse enough into the polyester fabrics and nylon / lycra fabrics combined. The amount of the triclosan ester derivative necessary to adequately effect the desired long-term antimicrobial characteristics of a fabric depends on the amount of the fabric being treated. Thus, the weight ratio between the weight of the fabric and the weight of the triclosan ester derivative within the dye bath should be from about 100: 0.01 about 100: 1. Preferably, this range is from about 100: 0.03 to about 100: 0.6, and more preferably from about 100: 0.1 to about 100: 0.25. Other types of specific processes for introducing the ester into a fabric include heat setting, warp gluing and any other process which may include sufficient heating and sufficient time for diffusion of the ester within the individual fibers of the treated fabric. 0 In fact, the use of triclosan esters only provides an effective way to apply and diffuse the triclosan itself within a cloth substrate. It is considered that the antimicrobial properties of a textile treated with triclosan ester are obtained from the triclosan compound itself which is generated very slowly by hydrolysis of the ester in an aqueous environment or containing moisture. This method is thus highly effective in providing antimicrobial properties, as well as providing a diffused, antimicrobial, durable fiber finish. The triclosan is illustrated by the following figure (I): This compound, with a free hydroxyl group, dissolves easily in water at high pH. Also triclosan has a tendency to volatilize at high temperatures. Preferred ester derivatives, which have esterified the hydroxyl group of triclosan, are illustrated by the following figure (II): wherein R is selected from the group consisting mainly of C 1 -C 0 alkyl or cycloalkyl, aryl and substituted aryl. Specifically, the preferred compounds are triclosan acetate, triclosan propionate, triclosan benzoate, triclosan 4-nitrobenzoic acid and triclosan hexanoate. Triclosan acetate is particularly preferred. In another embodiment, R is a phosphate group to form a triclosan phosphate ester. A compound defined by figure (II) does not dissolve in water and generally has a much lower volatility than triclosan itself. For example, the thermal gravimetric analysis of triclosan and the acetate thereof shows this difference substantially in volatility, as shown in the following Table.

TABLE Thermal Gravimetric Analysis The measurements were obtained from the percent weight lost for the following samples using Perkin-Elmer TGA 7 where the temperature was swept from 40 ° to 250 ° at 20 ° C / minute. At the end of the temperature sweep for each, the following results were obtained: Shows% weight loss Triclosan 62 Triclosan acetate 12 The oleophilicity of this particular ester derivative facilitates the exhaust on the surfaces of the hydrophobic fiber and also facilitates diffusion in each individual fiber. In contrast, the triclosan itself, with a free hydroxyl portion, does not readily volatilize on the surface of the fiber and can not diffuse appreciably on the individual surfaces in an aqueous dye bath. This ability to diffuse within the individual fibers provides a form in which only small but effective antimicrobial amounts of triclosan are formed on and within the fabric. Washing and bleaching, particularly with chlorinated agents, does not affect the durability of the antimicrobial characteristics of the esters. In general, a surface treatment application, such as coating alone or impregnation within the interstices of fabrics with triclosan esters or triclosan itself, can be easily removed by a high pH detergent solution within a wash cycle. , and thus would not provide a durable antimicrobial treatment for textiles. The triclosan esters diffused into the fibers of a fabric are not in contact with the washing liquid and therefore can not be easily removed. However, the triclosan ester within the fabric has the ability to migrate to the surface of the fabric at a very low speed to provide the antimicrobial effect on the substrate.

Another important aspect regarding the differences between triclosan and its ester derivatives is the fact that it is known that triclosan causes irritation to the membranes of the nervous system when it is inhaled. The derivatives of the triclosan ester at this particular concentration of and in this manner of use do not present such deleterious and potentially harmful problems. Due to the low amount, although effective as antimicrobial, of the triclosan formed with hydrolysis of the ester while it is present in a cloth substrate, this problem is not of great importance. However, in order to possibly effect a long-lasting antimicrobial finish on the fabrics using triclosan alone, the enormous amount of the compound required would probably present a serious health risk. Any other normal textile additives, such as colorants, sizing compounds, ultraviolet light absorbers and softeners may also be incorporated or introduced into the surface of the treated fabric substrate. The finishes particularly desired as optional for the fabrics of the inventive are impurity-releasing agents that improve the wettability and washing ability of the fabric. Preferred impurity-releasing agents include those that provide hydrophilicity to the surface of the polyester. With this modified surface, again, the fabric imparts improved comfort for a wearer by attracting moisture. The preferred impurity-releasing agents contemplated within this invention can be found in US Pat. Nos. 3,377,249; 3,535,151; 3,540,835; 3,563,795 3,574, 620; 3,598,641; 3,620,826; 2,632,420; 3,649,165 3, 650, 801, 3,652,212; 3,660,010; 3,676,052; 3,690,942 3,897,206; 3,981,807; 3,625,754; 4,014,857; 4,073,993 4, 090, 844; 4,131,550; 4,164,392; 4,168,954; 4,207,071 4,290,765; 4,068,035; 4,427,557 and 4,937,277. These patents are therefore incorporated herein by reference. The treated fabric can be incorporated in a cloth, tablecloth, towel, napkin, or any other type of fabric in which antimicrobial properties are desired. The triclosan esters of this invention can be produced by the method described in U.S. Patent No. 3,904,696, supra, incorporated above in its entirety as a reference.

BEST MODE FOR CARRYING OUT THE INVENTION The following examples are indicative of the preferred embodiments of the method of use and application of this invention: EXAMPLE 1 Application of triclosan ester by diffusion Equal amounts of triclosan acetate (2,4,4'-trichloro-2'-acetoxy-diphenyl ether) and Triton ™ X-301 were introduced into a flask with stirring. With addition of 50% by weight of water to the mixture, a stable dispersion of triclosan acetate with a content of 50% by weight was obtained. The dispersion was then introduced into a Hisaka jet stain machine. Then a woven fabric of a 50/50 nylon / lycra combination was added in the machine so that the ratio of the weight percent of the fabric to the ester was 100: 0.1. The machine was then closed, stirred and heated to a temperature of about 120 ° C for about 20 minutes, then allowed to cool to room temperature. At this time the fabric was separated from the machine, dried and analyzed for its antimicrobial properties. Using the AATCC [sic] 14-1993 test method, the fabric showed 100% contact inhibition and a zone of 3 mm inhibition when tested against Staphylococcus aureus. The cloth was then subjected to an equivalent 0 of 25 normal house washes and subsequently treated for the same contact inhibition and zone of inhibition. After 25 washes, the cloth retained the same level of contact inhibition and showed an area of 1 mm of inhibition against Staphylococcus aureus.

EXAMPLE 2 Application of triclosan ester by diffusion The same procedure was used as in Example 1, except that the treated fabric was a 100% polyester woven fabric of 0.70 denier per filament yarn with a weight of 6 oz / yd and the ratio of the percent by weight of the fabric to the ester was 100: 0.25. Again, the same results were obtained for contact inhibition and zone of inhibition after zero washes and after 25 washes when tested against Staphylococcus aureus.

EXAMPLE 3 (Comparative) Application of triclosan by impregnation According to the only application method described within Swiss Patent 459, 656, a textile was impregnated with triclosan and analyzed for its long-lasting antimicrobial properties. Ultrafresh® NM, a 3% active triclosan dispersion available from Thomson Research Associates, Toronto, Canada, was -diluted with water at 0.15% of the content of 0 active triclosan. The same fabric used in EXAMPLE 2 above was saturated with this solution and squeezed to absorb approximately 100% of the solution. The cloth was then immediately dried at 320 ° F for 3 minutes in a convection oven. The treated fabric showed a zone of 7 mm of inhibition and 100% of contact inhibition when tested against Staphylococcus aureus using the AATCC test method [sic] 147-1993. After five cycles of normal washing and drying laundry, however, the fabric showed no inhibition zone and 0% contact inhibition.

EXAMPLE 4 Application of triclosan acetate by impregnation According to the only application method described within Swiss Patent 459,656, a textile was impregnated with triclosan ester, acetate, and analyzed for its long-lasting antimicrobial properties. The same dispersion of triclosan acetate as used as in EXAMPLE 1 was diluted to an active ester content of 0.15%. The same polyester fabric (polyethylene terephthalate) used in EXAMPLE 2 was then saturated with the diluted and squeezed solution to absorb approximately 100% of the solution. The cloth was immediately dried in a convection oven at 320 ° F 0 for 3 minutes. The treated fabric showed approximately 4 mm zone of inhibition and 100% contact inhibition using the AATCC [sic] 147-1993 test method against Staphylococcus aureus. After five cycles of normal washing and drying, the cloth showed no zone of inhibition and 0% inhibition by contact. Of course, there are many alternative embodiments and modifications of the present invention that are proposed included within the spirit and scope of the following clauses.

Claims (17)

1. A method for imparting long-lasting antimicrobial properties to a fabric consists of the sequential steps of: (a) providing at least one ester derivative of triclosan; and (b) contacting the triclosan ester derivative with a textile at a temperature and for a time sufficient to effect diffusion of the triclosan ester derivative within the individual fibers of the textile; wherein the textile consists of synthetic fibers; and wherein the weight ratio of the textile to the ester derivative of triclosan is within the range from about 100: 03 [sic] to about 100: 1.

The method of claim 1, wherein the triclosan ester derivative is selected from the group consisting primarily of a triclosan acetate, triclosan propionate, triclosan benzoate, triclosan 4-nitrobenzoate and triclosan hexanoate.

3. The method of claim 2, wherein the ester derivative of triclosan is a triclosan acetate.

The method of claim 1, wherein the fabric is a fabric selected from the group consisting primarily of woven, non-woven or knitted fabrics.

5. The method of claim 1, wherein the synthetic fabrics are selected from the group consisting of polyester, polyamide, acetate, polyolefin, acrylic, lycra and mixtures thereof.

The method of claim 6, wherein the synthetic fibers are selected from the group consisting of polyester, polyamide, lycra and mixtures thereof.

The process of claim 1, wherein the weight ratio of the textile to the ester derivative of triclosan is within the range of about 100: 0.1 to about 100: 0.25.

The method of claim 1, wherein at temperature within step (b) it is between about 80 and 130 ° C and the time in step (b) is from about 10 to about 120 minutes in duration.

The process of claim 1, wherein, before step (a), the ester derivative of triclosan is dispersed in water with a surfactant.

10. A method for imparting long-lasting antimicrobial properties to a fabric consists of the sequential steps 0 of: (a) providing an ester derivative of triclosan; (b) introducing the ester derivative of triclosan into a dye bath, wherein the dye bath contains at least one textile dye; (c) introducing a textile into the dyebath; (d) shaking the dyebath and raising the temperature of the dyebath to a temperature, under normal dye bath pressure, and for a period sufficient to effect diffusion of the triclosan ester derivative and the dye within the individual fibers of the textile; and (e) removing the textile from the dyebath; wherein the textile consists of synthetic fibers; and wherein the weight ratio of the textile to the ester derivative of triclosan is within the range from about 100: 03 [sic] to about 100: 01 [sic].

11. The method of claim 12, wherein the triclosan ester derivative is selected from the group consisting mainly of a triclosan acetate, triclosan propionate, triclosan benzoate, triclosan 4-nitrobenzoate and triclosan hexanoate.

The method of claim 13, wherein the triclosan ester derivative is a triclosan acetate.

The method of claim 12, wherein the fabric is a fabric selected from the group consisting primarily of woven, non-woven or knitted fabrics.

The method of claim 15, wherein the synthetic fabrics are selected from the group consisting of polyester, polyamide, acetate, polyolefin, acrylic, lycra and mixtures thereof.

15. The method of claim 16, wherein the synthetic fibers are selected from the group consisting of polyester, polyamide, lycra and mixtures thereof. The process of claim 12, wherein the weight ratio of textile to ester derivative of triclosan is within the range of about 100: 0.1 to about 100: 0.25. The method of claim 12, wherein the temperature in step (d) is between about 80 and 130 ° C, and the period within step (d) is from about 10 to about 120 minutes in duration.