Odor reduction and bacterial control of textile materials

Abstract

A composition for odor reduction and bacterial control of textile materials is provided. The composition includes a GRAS additive or ingredient having antimicrobial or preservative properties and a carrier. The composition may include an essential oil. The GRAS additive or ingredient can be a minimal hazard disinfectant. The composition may include a carrier. Methods of using the composition and articles treated with the composition are also provided.

Description

[Technical field]

[0001] REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Patent Application No. 62 / 955161, filed in the U.S. Patent and Trademark Office on December 30, 2019, U.S. Provisional Patent Application No. 62 / 955155, filed on December 30, 2019, and U.S. Patent Application No. 17 / 128849, filed on December 21, 2020, the disclosures of which are incorporated herein by reference in their entirety.

[0002] FIELD OF THEINVENTION The present invention relates to compositions and methods for odor reduction and bacterial control of textile materials, particularly compositions and methods for odor reduction and bacterial control of textile materials using Generally-Recognized-as-Safe (GRAS) antimicrobial / preservative additives or ingredients, such as food preservatives. [Background technology]

[0003] Current bacterial control on textile garments relies heavily on the use of metal-containing activators such as silver or zinc. These chemicals have poor wash durability, result in discoloration of the fabric, and cannot be easily incorporated into most textile manufacturing processes. Furthermore, the presence of "heavy metals" in process effluents in textile factories has been of significant concern to regulators and policy makers.

[0004] Alternatively, organic molecules such as quaternary ammonium silanes, phenols, and azoles can be used to treat fiber surfaces. These chemicals require extensive formulation efforts to reduce hydrophobicity or increase durability, and are only applicable for fiber filling applications.

[0005] To date, the only chemical that can be applied to many of the textile manufacturing processes without technical problems is zinc pyrithione. However, this unique chemical is subject to regulatory oversight. Such oversight may ultimately render zinc pyrithione unavailable for reducing odor- and stain-causing bacteria on textile surfaces.

[0006] Therefore, this technology cannot be used for exhaustion or padding, has a negative effect on fiber properties, and can be classified as toxic. Therefore, it is essential to have new solutions for odor and bacterial control on fiber surfaces.

[0007] Thus, there is a need for alternative chemicals for bacterial and odor control that are effective, safe, environmentally friendly, easy to apply with current factory technology, and affordable to use. Summary of the Invention

[0008] The present invention relates to compositions for odor reduction and bacterial control of textile materials using generally recognized as safe (GRAS) additives or ingredients having antimicrobial or preservative properties. Examples of GRAS additives are, but are not limited to, minimal hazard disinfectants, food preservatives, among others.

[0009] In an embodiment of the invention, the composition comprises a compound selected from the group consisting of GRAS additives or ingredients having antimicrobial or preservative properties. The composition may further comprise an ingredient selected from the group consisting of essential oils, carriers, and combinations thereof.

[0010] In an embodiment of the invention, the composition is in the form of a concentrate.

[0011] In an embodiment of the invention, the composition further comprises an odor mitigating compound selected from the group consisting of metal oxides, activated carbon, sodium carbonate, calcium carbonate, zinc ricinoleate, and combinations thereof.

[0012] In an embodiment of the invention, the GRAS antimicrobial additive / preservative is an organic acid.

[0013] In an embodiment of the invention, the organic acids have a total active concentration of 5-60% by weight of the composition.

[0014] In an embodiment of the present invention, a method is provided for odor reduction and bacterial control of textile materials comprising applying a composition comprised of a GRAS antimicrobial additive / preservative and a carrier.

[0015] In an embodiment of the invention, an article, such as a textile material, is provided that is treated with the composition of the invention.

[0016] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. [Brief description of the drawings]

[0017] The present invention will become more fully understood from the detailed description and the accompanying drawings, which are not necessarily to scale.

[0018] [Figure 1] FIG. 1 is a graph showing the effect of "Generally Recognized as Safe (GRAS)" compounds in the absence of home laundering (HL) as evaluated using the AATCC TM100 protocol.

[0019] [Diagram 2] Figure 2 is a TGA graph showing percent weight loss versus temperature for each of benzoic acid, sorbic acid, and citric acid measured at temperature ramp rates of 10°C / sec (".001" sample) and 30°C / sec (".002" sample). The graph gives an indication of the thermal stability of the samples and the temperature at which they decompose.

[0020] [Diagram 3] FIG. 3 is a graph showing efficacy results after 25 home laundry (HL) cycles.

[0021] [Figure 4] Figure 4 is a graph showing post-reduction wash efficacy results without home laundering (0 HL) evaluated using AATCC TM100. Benzoic acid and sorbic acid are exhausted on polyester fabric to show post-reduction wash efficacy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The following description of embodiments of the present invention is merely exemplary in nature and is not intended to limit the invention, its application, or uses in any manner. The following description is provided herein for illustrative purposes only for the purpose of providing an enabling disclosure of the invention, but does not limit the scope or substance of the invention.

[0023] The present invention relates to compositions and methods for imparting bacterial and odor control to textile materials using environmentally friendly ingredients without compromising the dyeing process of the textile material. The present invention includes active ingredients that may possibly alter the dyeing somewhat during the textile dyeing and treatment process, but the present invention also simultaneously protects the dye molecules from alterations during the textile dyeing and treatment process.

[0024] In an embodiment of the present invention, a "Generally Recognized as Safe (GRAS)" composition is provided for imparting odor reduction and bacterial control to textile materials. The acronym "GRAS" is used by federal regulatory agencies to indicate a substance that is considered "generally recognized as safe" when used in accordance with good manufacturing practices. For example, such regulations include 21 CFR 182, 21 CFR 184, and 21 CFR 186.

[0025] Examples of GRAS ingredients or compounds include, but are not limited to, food preservatives. As a classification, food preservatives may be suitable for use in the compositions of the present invention because they are classified as minimal hazard disinfectants while providing antimicrobial effects. However, food preservatives suitable for use in the present invention should be able to withstand textile processing environments, including temperatures above 150°C, be water dispersible, compatible with acetic acid, and have a low skin toxicity profile.

[0026] In an embodiment of the present invention, the antimicrobial additive is an organic acid. Examples of organic acids include, but are not limited to, benzoic acid, propionic acid, sorbic acid, citric acid, lactic acid, ascorbic acid, acetic acid, erythorbic acid, fumaric acid, malic acid, glycolic acid, derivatives thereof, and combinations thereof. Preferred organic acids include, but are not limited to, benzoic acid, sorbic acid, citric acid, and combinations thereof.

[0027] Other examples of GRAS excipients suitable for use in the present invention are sodium benzoate and potassium sorbate.

[0028] The compositions of the present invention can include one or more additives, for example, essential oils can be added along with benzoic acid, sorbic acid, or combinations thereof to provide activity against fungal species.

[0029] Examples of essential oils are cedar oil, tea tree oil (Melaleuca alternifolia), eucalyptus oil (Eucalyptus globulus or E. radiata), clove oil (Eugenia caryophyllata), oregano oil (Origanum vulgare), thyme oil (Thymus vulgaris), geranium oil (Pelargonium graveolens), cinnamon oil (Cinnamomum zeylanicum), peppermint oil (Mentha piperita), lemongrass oil (Cymbopogon flexuosus), basil oil (Ocimum basilicum), lavender oil (Lavandula angustifolia), lemon oil (Citrus limon), rosemary oil (Salvia rosmarinus), bergamot oil (Citrus bergamia), perilla oil (Perilla frutescens), coriander oil (Coriandrum Preferred essential oils include, but are not limited to, cinnamon oil (Cinnamomum zeylanicum), lemongrass oil (Cymbopogon flexuosus), thyme oil (Thymus vulgaris), cedar oil, citron oil, peppermint oil, rosemary oil, clove oil, and combinations thereof. Some essential oils, such as peppermint oil and cinnamon oil, have little or no antibacterial activity but have unique effects on fungal species.

[0030] Additionally, it is desirable to control odors that are not associated with microorganisms on the fiber surface. Organic acids (or combinations thereof) can provide the ability to neutralize alkaline-based odors such as ammonia. Additionally, organic acids with aryl groups have the ability to inhibit ring-based odorants such as pyridine. To complement these effects, additional odor-mitigating compounds can be added to the combination of benzoic acid, sorbic acid, and / or essential oils for the removal of existing odors. The addition of odor-mitigating compounds results in a unique blend that can provide antimicrobial and odor control benefits. Examples of odor-mitigating compounds include, but are not limited to, metal oxides, activated carbon, sodium carbonate, calcium carbonate, and zinc ricinoleate.

[0031] The addition of metal oxides (e.g., ZnO) to any of the chemicals results in a unique blend that can provide antimicrobial and odor control benefits. Aldehyde-based odors such as ammonia, nonanal, and alkaline odors such as pyridine were tested (by GC measurements) to determine if odor levels were reduced. This function would allow the active acids to control odors not generated by bacteria in addition to reducing bacterial odors by controlling bacterial populations.

[0032] In an embodiment of the invention, the compositions of the invention comprise a stable suspension of benzoic acid, sorbic acid, or a combination thereof, at a total active concentration of 5-60% by weight of the composition, preferably 10-50% by weight. The acid is present in a carrier, which may be water or an organic solvent, such as a glycol, such as propylene glycol, dipropylene glycol. Alternatively, a surfactant may be utilized to dissolve the acid, allowing the compositions of the invention to be a solution rather than a dispersion. However, another way of incorporating the antimicrobial agent is to formulate a salt of the acid, such as sodium benzoate, in the case of benzoic acid, and add this salt-based formulation to the exhaustion bath, and then add another acid to the exhaustion bath to lower the pH of the exhaustion bath and convert the benzoate to benzoic acid. This would allow the concentrate to be formulated as an aqueous liquid that is easily handled due to the high solubility of the salt in water.

[0033] The compositions of the invention may optionally contain essential oils at a total concentration of from 1 to 20% by weight of the composition, and may optionally contain metal oxides at a total concentration of from 1 to 20% by weight of the composition, preferably from 5 to 10%.

[0034] In an embodiment of the present invention, a method of using a fiber treatment composition, preferably a GRAS fiber treatment composition, is provided. The composition of the present invention can be applied to a fiber material by any application method known in the art of the textile industry. For example, two traditional application methods for fibers are exhaustion and budding.

[0035] Textile mills utilize liquid processing processes such as exhaustion or budding to incorporate auxiliary chemicals such as antimicrobials and finishing agents into the fibers. Since liquid components are required in the fiber manufacturing process, the organic acids are either in liquid form (stable solution or dispersion) or dispersed in water by the consumer prior to its use. Many organic acids are not easily miscible with water. It has been observed that when dispersing organic acids in water, the acid precipitates within a short time and forms a packed bed that is difficult to redisperse in a user-friendly manner. To address this issue, dispersants can be added to the fiber composition or bath. For example, non-ionic dispersants can be used for this purpose. Dispersants wet the acid surface, helping to create distance between individual particles and reducing the viscosity of the slurry at high loads. Another non-limiting example of a dispersant is a dispersible inorganic polymer crystal that has the ability to act between acid particles and impart thixotropic properties to the rheology of the concentrate. This additive further ensures ease of redispersion of the acid particles after consumer use.

[0036] Interestingly, in the exhaust dyeing process, benzoic acid and sorbic acid are introduced into the surface and internal amorphous regions of PET along with the dye by a thermally driven glass transition physical change that occurs in the PET fiber at the target working temperature. The disperse dye is milled with a dispersant. These dispersants are essentially carbon chains terminated with dissociable acid functional groups. The dispersant, upon dissociation, carries the dye molecules into the PET fiber at the correct working temperature by micellar action. Once the micelles are in proper proximity to the PET structure, van der Waals forces arise and the dye molecules attach to the internal amorphous regions of the PET fiber. The micellar surfactant molecules are then attracted to different unbound dye molecules and the process begins again. Organic acids such as benzoic acid and sorbic acid undergo dissociation and develop a negative charge on the hydroxyl oxygen, thus not requiring additional dispersants. The organic acids therefore become polar in nature and are attracted to the polar dispersants introduced along with the dye. The organic acids become part of the micelles, which carry the dye and route it close to the surface or internal amorphous regions of the PET. Embedding the organic acids into the PET fibers during the textile dyeing process prevents the reduction washing step from damaging the organic acids, and the textile material still retains its effectiveness after washing (see Figure 4).

[0037] The composition of the present invention can be in the physical form of a liquid concentrate. The acid must first be dispersed in a concentrated form and then can be processed to allow for actual application. The fiber exhaust process generally requires the use of water as a vehicle to carry additives and dyes for the treatment of fabrics.

[0038] In an embodiment of the invention, the composition of the invention, preferably in the form of a polymer concentrate, such as a polymer binder for coating, comprises benzoic acid, sorbic acid, or a combination thereof. For the polymer binder, a concentration in the range of 0.1-40% by weight of solids based on the solution is required. If more than one acid is used in combination, the total weight of active acids is 5-60% by weight of the final composition, preferably 5-40% by weight. The treatment composition is added as a concentrate in the exhaust or padding bath to allow a final active concentration of 0.1-5% by weight of the fabric. For example, the essential oil (if present) can be at a final concentration of 0.05-1% by weight of the fabric, and the odor mitigating compound (if present) can be at a final concentration of 0.05-1% by weight of the fabric.

[0039] Inorganic polymeric rheology modifiers can be used with the concentrates of the present invention to prevent or reduce the adverse effects of the presence of organic acids on some dyes used in the fiber exhaust process. Organic acids such as benzoic acid or sorbic acid may change the color tone of the dye. The change in color tone is generally undesirable because the fiber mill does not have the ability to adjust the dye blend once the exhaust process has begun. Unexpectedly, the inorganic polymeric rheology modifier helps to preserve and stabilize the color of the dye in addition to adjusting the rheological properties of the concentrate. The inorganic additives provide an oriented matrix with nonionic dispersants, organic acids, and water molecules, providing a less harsh environment for the dye in the exhaust process.

[0040] This application method is used for the treatment of textile materials, including synthetic and natural fibers.

[0041] The textile compositions of the present invention are non-hazardous at end-use levels, applicable to most forms of textile manufacturing, stable to washing, and do not affect textile properties. The selected GRAS acids are thermally stable at relevant processing temperatures as indicated by the thermogravimetric analysis data shown in Figure 2.

[0042] After the dye exhaustion process, the fiber fabric can be exposed to a reducing agent such as sodium hydrosulfite and / or NaOH to remove unreacted dye from the fiber in a process known as "reductive clear." Because benzoic acid and sorbic acid could theoretically be removed during the reductive clear process, fibers having either of these chemicals were evaluated after reductive clearing to ensure that these chemicals would remain in the industrial process.

[0043] During the fiber treatment and dyeing process, the active ingredients of the present invention become part of the fibers of the fabric, where they cannot be washed off even by multiple washings. The use of surfactants, wicking agents, leveling agents, softeners, and binders ensures the proper distribution of the active ingredients and their molecular orientation during the exhaust process. The emulsion surfactants aid in the formation of micelles containing the active ingredients. The wicking agents are used to improve the interface of polar and non-polar surfaces during exhaustion. The leveling agents are added to ensure uniform distribution of the dye to the fabric. The fiber binders used in the dye exhaust process remain on the fabric and contribute to the durability of the active ingredients. The fiber softeners are included to give the fabric a soft feel when the binders are used. The disperse dye chemicals, and the surfactants used in addition, allow the formation of micelles that carry the dye molecules into the PET fibers at the correct working temperature. Once the micelles are in proper proximity to the PET structure, van der Waals forces are generated and the dye molecules attach to the internal amorphous regions of the PET fibers. The micellar surfactant molecules are then attracted to different unbound dye molecules and the process begins again. This indicates that the organic acids similarly undergo dissociation, becoming negatively charged ionic acids that are attracted to the hydrophilic heads of the micelles and find their way in close proximity to the surface and / or internal amorphous regions of the PET. Embedding the organic acids within the PET fibers during the textile dyeing process prevents the organic acids from washing away with repeated washing, which provides durability of the antimicrobial effect.

[0044] In an embodiment of the present invention, there is provided an article, such as a textile material, that is treated with the composition of the present invention. It is contemplated within the scope of the present invention that other materials and objects may be treated with the composition of the present invention. EXAMPLES

[0045] Comparative Example

[0046] As shown in FIG. 1, the use of only the respective salts of benzoic acid, sorbic acid, and citric acid (sodium benzoate, potassium sorbate, and trisodium citrate) provided a relatively low level of effectiveness. Furthermore, the use of salts to treat the garment surface made the fabric feel stiff after application. Also, salts have good water solubility, which reduces wash durability. These drawbacks make salts unsuitable for use on fabrics. Note that no attempt was made in this case to convert the salts to acids by lowering the pH of the liquid.

[0047] Example 1

[0048] As shown in Figure 3, when washed repeatedly according to the industry recognized washing procedure AATCC 38, each of the benzoic and sorbic acids was able to maintain efficacy even after multiple wash cycles, a typical requirement in the textile industry. Citric acid alone was not able to maintain efficacy after the same wash procedure as the benzoic and sorbic acid treatments.

[0049] Example 2

[0050] Experiments were carried out to demonstrate the fungicidal properties of textile materials treated with 0.4% cinnamon oil. Following industrial method AATCC 30(III), the addition of the essential oil to either benzoic or sorbic acid after 4 days of exposure to Aspergillus niger cultures produced zones around the treated samples completely devoid of growth. This unique combination allowed the treated textile materials to be endowed with both antibacterial and antifungal activity.

[0051] Example 3

[0052] A textile dye exhaustion experiment was conducted using the same percentage ratios of three dyes (blue, red, and yellow), each in combination with each of three polyethylene terephthalate fabric samples. A first fabric sample (A) was exhausted of dye only. A second fabric sample (B) was exhausted of dye and active concentrate and incorporated an inorganic polymeric rheology modifier in which the amount of organic acid present corresponded to 0.5% by weight of the exhaustion bath. A third fabric sample (C) was exhausted of 0.5% by weight of the exhaustion bath of organic acid and dye, but did not incorporate a concentrate. The liquor ratio of the bath was 10:1.

[0053] The results showed that the color of sample (A) was much closer to the color of the second sample (B), while the color of sample (C) was clearly different. Thus, the blend of concentrates was more effective at matching the color compared to using only the organic acids.

[0054] The specific conditions for Example 3 are as follows. Benzoic acid was used at a treatment rate of 0.5% owb to make color comparisons: A was an untreated control with no benzoic acid, B was treated with 0.5% owb benzoic acid with the inclusion of concentrate, and C was treated with 0.5% owb benzoic acid without the inclusion of concentrate.

[0055] Example 4

[0056] The high dye loading samples were the most difficult to process using the exhaust dyeing technique. A test series was conducted using PET (polyester) and polyspandex fabrics. In this test series, the materials were tested in two different laboratories using a container style lab exhaust apparatus. In addition to the samples tested, an untreated fabric was evaluated for comparison. The following parameters were used in the exhaust process:

[0057] 10:1 liquid ratio

[0058] 12.5g / L benzoic acid dispersion, 40% benzoic acid

[0059] Exhaustion cycle at 130°C for 40 minutes

[0060] 5% Acid Disperse Dyes - Black

[0061] Reduction Cleaning - 0.3% NaOH & 0.4% Na hydrosulfite at 85°C for 20 minutes

[0062] Dry at 130℃ for 120 seconds

[0063] Samples were tested for antimicrobial efficacy using AATCC TM100-2019. Only Kp was tested as the indicator organism because any sample that was effective against Kp was also known to be effective against Sa.

[0064] TIFF0007627268000001.tif39166

[0065] Table 1 - Percentage bacterial reduction of treated samples at two different locations on polyester fabric from two different suppliers. The fabrics were tested as made and after 25 home washes (25HL). Each home wash was performed in a commercial drum washing machine according to AATCC Monograph M6 using Tide HE detergent.

[0066] The results in Table 1 show an average bacterial reduction rate of over 90% in all cases and over 99% in most cases. Each value is the average bacterial reduction rate of 24 test samples produced using two black dyes from different suppliers with and without leveling agent. No significant difference in effectiveness was found between the groups. The results in Table 1 therefore demonstrate the excellent wash durability of this technology.

[0067] Polyspandex was run in the same manner as PET in the same manner as above. This material is similar to PET but has an additional elastomeric component (90% PET, 10% spandex). The following results were obtained for this material:

[0068] TIFF0007627268000002.tif30166

[0069] In addition to efficacy testing, dye and fastness tests were performed on these samples since dye quality must not be affected by the antimicrobial treatment. The following standard textile quality control tests were performed on samples from the above two test sets, and untreated samples made in the same manner as these samples were evaluated for comparison.

[0070] Table 3 - Clock and colour fastness results for polyester materials TIFF0007627268000003.tif30165

[0071] TIFF0007627268000004.tif44166

[0072] These results show that the colorfastness and color of the treated fabric matches that of the untreated fabric, which gives the conclusion that the antimicrobial treatment proposed in this invention does not affect the colorfastness or color.

[0073] Example 5

[0074] Testing was carried out on a small scale Thiele exhaustion pilot unit as well as a Mathis JFO pilot scale apparatus, both of which use jets to forcefully impregnate the fibers with exhaustion liquor. As the data in the table below shows, the present invention has been used in an industrially relevant jet exhaust process with excellent results.

[0075] Table 5 lists the results from various runs showing processing in a jet exhaustion unit. These runs also show compatibility with different dye levels, leveling chemistries, reduction washes, and drying temperatures. Reduction Wash - Method A is 1% Na hydrosulfite, Method B is 0.3% NaOH, 0.4% Na hydrosulfite, "owg" is "on weight of goods".

[0076] TIFF0007627268000005.tif136165

[0077] Example 6

[0078] One possibility to introduce an organic acid such as benzoic acid into an aqueous system such as an exhaust liquor is to add a salt of the organic acid to the system and then lower the pH of the system below its pKa value. Commonly, acetic acid or citric acid is used in textile mills to control the pH of the liquor. The salt of benzoic acid is sodium benzoate, and the pKa value for this system is 4.2. According to the Henderson-Hasselbalch equation, if the pH is lowered below 3.6, 80% of the Na benzoate added to the system will be converted to benzoic acid. Using a water-soluble salt to acidify the liquor to a pH below 3.6 is a common way to put the composition of this invention into the exhaust liquor and allow aqueous formulation without the need to prepare a dispersion. The results in Table 6 are an example showing that acidifying the liquor bath using sodium benzoate is equivalent to treating with benzoic acid.

[0079] Table 6 - Polyester fabric was treated similarly to Example 4 above, except that sodium benzoate acidified with citric acid to a pH below 3.6 was used instead of benzoic acid to provide antimicrobial results. No visible differences were observed between the treated and untreated dyed fabric samples.

[0080] TIFF0007627268000006.tif26165

[0081] Thus, it will be readily understood by those skilled in the art that the present invention is susceptible to wide utility and application. Numerous embodiments and adaptations other than those described herein, as well as numerous variations, modifications, and equivalents, will be apparent from, or will be reasonably suggested to, those skilled in the art from, the present invention and the foregoing description thereof, without departing from the true spirit or scope of the present invention. Thus, although the present invention has been described in detail herein with reference to preferred embodiments thereof, it should be understood that this disclosure is merely illustrative and exemplary of the present invention and is provided solely for the purpose of providing a complete and enabling disclosure of the present invention. The foregoing disclosure is not intended, and should not be construed, to limit or otherwise exclude such other embodiments, adaptations, variations, modifications, and equivalents.

Claims

1. 1. A method for odor reduction or bacterial control comprising: Preparing the bath fluid; adding sodium benzoate to the bath solution; preparing a treatment bath solution by lowering the pH of the bath solution below the pKa of benzoic acid to convert sodium benzoate into benzoic acid; adding a colored dye to the bath solution; The method includes:

2. 1. A method for odor reduction or bacterial control comprising: Preparing the bath fluid; adding sodium benzoate to the bath solution; preparing a treatment bath solution by lowering the pH of the bath solution below the pKa of benzoic acid to convert sodium benzoate into benzoic acid; adding an inorganic polymeric rheology modifier to the bath liquid; The method includes:

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