Mgo aqueous dispersions and their use for functional finishing of textile and odor removal

Abstract

This invention provides methods for imparting to a textile material absorbability of odorous compounds for neutralizing odors in the textile material, comprising adding a regenerable odor absorbent to said textile material, wherein the absorbent comprises MgO / Mg(OH)2 particles having a BET-measured surface area of 5-600 m2 / g at a "dry add-on" level of 0.1%-2 of MgO / Mg(OH)2.

Description

MgO aqueous dispersions and their use for functional finishing of textile and odor removalField of the invention

[0001] The present invention relates to the use of textile finishing formulations comprising aqueous dispersions of magnesium oxide for removal of odor in textiles.Background of the invention

[0002] Textile materials are regularly exposed to various odors, such as body odors, kitchen odors such as frying odors, etc. These odors may become an inconvenience, especially during the time interval when a change of clothing or laundry is not possible or practical.

[0003] WO2021199049A1 discloses compositions and aqueous dispersions comprising magnesium oxide and hydroxide for imparting anti-bacterial and / or antiviral properties to textile products. The anti-microbially effective amount reported in WO2021199049A1was an MgO / Mg(OH)2dry add-on level of at least 2%.Description of the invention

[0004] The present invention is based on the surprising discovery that magnesium oxide and magnesium hydroxide particles are able to absorb odorous compounds and reduce the odor emissions of a textile at very low add-on levels, i.e. belowtheir anti-microbial threshold amount, e.g. lowerthan 2% weight of MgO / Mg(OH)2, e.g. lower than 1.8% weight of MgO / Mg(OH)2calculated as “dry add-on” level as defined below. Hereinafter, the term MgO / Mg(OH)2is used to indicate either individual component ortheir mixture.

[0005] Moreover, it was found that during laundry, the MgO / Mg(OH)2particles release the odor molecules to the wash-water, and their surface area becomes free again for absorption of new molecules, thus regenerating the odor reduction effect. That is, the MgO / Mg(OH)2absorbent of the invention is regenerable, capable of regaining odor absorbing capacity upon laundry, e.g., at least 25 cycles of laundry MgO / Mg(OH)2was incorporated into a textile finishing formulation that maintains theability of the MgO / Mg(OH)2contained therein to function as an odor absorber while providing good aesthetics, color fidelity and multi laundry durability.

[0006] The capacity of the MgO / Mg(OH)2of the invention to absorb malodor molecules can be measured by standard tests employing body odor molecule analogues such as isovaleric acid, acetic acid and nonenal. We have shown that MgO / Mg(OH)2particles are able to absorb odorous compounds over a broad range of specific surface areas and have identified the grade and add-on level to fabric that are most effective yet can be incorporated in an efficient and durable textile finishing formulation. The odorous compounds are presumably captured by and locked in the MgO particles. It has also been demonstrated that the odor absorption capacity of magnesia particles is preserved on the fabric treated with the subject formulations, compared to a non-treated fabric.

[0007] Odorous compounds include -but are not limited to compounds such as ketones (e.g. 1-hexen-3-one, 2-heptanone, 2-octanone, 1-octen-3-one, 2- nonanone, Medium-chain ketones), esters (e.g. Ethyl-2-methylpropanoate, Ethyl butanoate, Methyl-3-methyl-hexanoate, Methyl laurate, Methyl myristate 2- Aminoacetophenone, Diethyl phthalate), aldehydes (e.g. Methional, Hexanal, (Z)-4- heptenal, Octanal, (E)-2-octenal, Cis / trans-2-nonenal, (E,Z)-2,4-nonadienal, (E,Z)- 2,6-nonadienal, Decanal, (E,E)-2,4-decadienal, (E)-4,5-epoxy-E-2-decenal, 4- methoxybenzaldehyde), alcohols (e.g. Oct-1-en-3-ol, 2-nonanol, 1-Decanol, 1- Dodecanol, 2-Phenylethanol, 2-Methoxyphenol (guaiacol)), naphthalene, acid compounds (e.g. ethanoic acid (acetic acid), 2-methylpropanoic acid (isobutyric acid), butanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid (isovaleric acid), 3-methyl-2-hexenoic acid, 4-methyl-3-hexenoic acid, 5-methyl-4-hexenoic acid, 3-methyl-3-hydroxy-hexanoic acid, 6-heptenoic acid, 4-methyloctanoic acid,4-ethyloctanoic acid); steroid compounds (e.g. 5-a-androstenol, 5-a-androstenone,5-a-androst-2-en-17-one, 5-a-androst-16-ene-3-one); sulfur compounds (e.g. 3- methyl-3-sulfanyl-hexan-1-ol, dimethyl disulphides, dimethyl trisulphides, benzylmercaptan), etc. (see for example table 1 of Microorganisms 2020, 8, 1709; doi:10.3390 / microorganisms8111709).

[0008] The invention may be especially useful for people working in an odorous environment orwhose activity is prone to odor production, such as athletes, cooks, garbage collectors, chemists, etc.

[0009] Different grades of MgO have been tested for their activity in textile products and MgO particles were found to absorb odorous compounds and reduce or neutralize the odor of textiles in which they are embedded (e.g., polyester fabrics, cotton fabrics, etc.). In particular, it has been found that magnesium oxide particles having a BET-measured surface area of 5-600 m2 / g, such as a surface area ranging from 5 to 200 m2 / g, e.g. from 20 to 200 m2 / g, or from 50 to 200 m2 / g, such as a surface area of 50-180 m2 / g, 20-30 m2 / g, 50-80 m2 / g, 120-200 m2 / g, or 130-190 m2 / g, had the best absorbing capabilities.

[0010] Thus, in a first aspect, the present disclosure provides a method for imparting absorbability of organic odorous compounds to a textile material comprising the step of adding to the textile material an absorbing agent able to absorb said odorous- compounds, wherein the absorbing agent comprises MgO / Mg(OH)2particles having a BET-measured surface area of 5-600 m2 / g, such as a surface area ranging from 5 to 200 m2 / g, e.g. from 20 to 200 m2 / g, or from 50 to 200 m2 / g, such as a surface area of 50-180 m2 / g, 20-30 m2 / g, 50-80 m2 / g, 120-200 m2 / g, or 130-190 m2 / g, to obtain a dry add-on level of MgO / Mg(OH)2of 0.1 -2%, such as 0.1 -1 .8%, such as 0.25-1 .5%, 0.5- 1%. In some embodiments, said agent is provided as a textile finishing aqueous dispersion, for application onto the textile, as disclosed herein. For example, the dispersion may be provided as a concentrate that is diluted before application to the textile product. The textile material, to which MgO / Mg(OH)2is applied according to the invention, may include fibers (prior to weaving or knitting), fabrics made up of fibers, e.g., natural fibers, synthetic fibers, or any combination thereof; and articles made of fabrics (e.g., clothing).

[0011] The present disclosure also provides a method for imparting odor absorbability to a textile material by embedding an odor absorbing agent within a textile material, e.g., a fabric made up of natural fibers, synthetic fibers, or any combination thereof, wherein the odor absorbing agent comprises MgO / Mg(OH)2particles having a BET-measured surface area of 5-600 m2 / g, such as a surface area ranging from 5 to 200 m2 / g, e.g. from 20 to 200 m2 / g, or from 50 to 200 m2 / g, such as a surface area of 50-180 m2 / g, 20-30 m2 / g, 50-80 m2 / g, 120-200 m2 / g, or 130-190 m2 / g, to obtain a dry add-on level of MgO / Mg(OH)2of 0.1-2%.

[0012] That is, the present disclosure provides a method for reducing the absorption of volatile odorous compounds by a textile fabric. Using the present methods, the volatile odorous compounds are reversibly adsorbed onto the MgO / Mg(OH)2particles instead of being absorbed by the textile fibers.

[0013] As MgO is a water-insoluble powder, a concentrated MgO-containing formulation has been developed by dispersing MgO in water with the aid of specific additives (e.g., dispersants, thickeners), creating a smooth free flowing homogeneous aqueous MgO dispersion and optionally in the presence of a binder (needed to affix the active compounds to the fabric). Such a concentrated dispersion presents many advantages, especially regarding handling and transport, as water can be added on-site, at the textile finishing facility After dilution, the concentrated MgO aqueous formulation can be used as a textile finishing composition to deliver the MgO to the fabric by conventional techniques employed by the textile industry, such as padding, coating, spraying, and dipping. The dilution rates depend on both the targeted dry add-on level desired and the wet pick-up of the different textiles. For example, for cotton, nylon, modal fabrics and cotton-rich blends, typical dilution rates may be 20 g concentrate / l on the basis of 100% wet pick-up or 25 g / l on the basis of 80% wet pick-up. For polyester, typical dilution rates comprise 32g / l on the basis of 60% wet pick-up, or 25 g / l on the basis of 80% wet pick-up. An 80% wet pick up means that 1 kg fabric takes up 0.8 kg solution for a total weight of 1 ,8kg before drying After drying and curing, an MgO / Mg(OH)2dry add-on level of 0.1-2% is obtained.

[0014] Accordingly, one aspect of the present invention is a stable, concentrated, odor-reducing and / or odor neutralizing textile finishing aqueous dispersion comprising magnesium oxide at a concentration higher than 21 % by weight, a surfactant / dispersant and a thickener, and optionally a binder (herein referred to as the concentrate).

[0015] In some embodiments the odor neutralizing textile finishing aqueous dispersion concentrate according to the present disclosure comprises: from 60 to 70% by weight of water; from 21 to 30% by weight of MgO; from 0.5 to 1 % by weight of dispersant; and from 0.1 to 0.5% by weight of thickener; and optionally from 3 to 10% by weight of a binder.

[0016] In some embodiments, the odor neutralizing textile finishing aqueous dispersion concentrate according to the present disclosure comprises 65-66% water, 26-27% MgO, 0.6-0.7% dispersant, 0.35-0.45% thickener, and 6-7% binder.

[0017] In some embodiments, the odor neutralizing textile finishing aqueous dispersion concentrate according to the present disclosure comprises: a) 63-68%, e.g., 65-66% by weight water, b) 24-29%, e.g., 26-27% by weight MgO, c) 0.4-0.9%, e.g., 0.6-0.7% by weight dispersant, d) 0.15-0.60%, e.g., 0.35-0.45% by weight thickener, and e) 4-9%, e.g., 6-7% by weight binder.

[0018] In some embodiments the surfactant / dispersant according to the present disclosure is an anionic dispersant, e.g., an anionic copolymer dispersant, such as acid resin polycarboxylate copolymer (suitable commercially available dispersants include TERSPERSE 2700); the thickener according to the present disclosure is a cellulose derivative or a swellable synthetic polymer, especially hydroxy ethyl cellulose (HEC), and the binder according to the present disclosure is an acrylate binder. With the help of a polycarboxylate dispersant such as TERSPERSE 2700, MgOwas formulated into water at high concentration, e.g., >20% by weight, such as 21 % or more by weight. The combination of the above-mentioned formulation aids leads to a smooth, free flowing homogeneous dispersion, showing stability against settling for overthree months.

[0019] In some embodiments, the thickener is a cellulose derivative, such as hydroxy ethyl cellulose (HEC), the surfactant is an anionic acid resin polycarboxylate copolymer, and / or the binder is an acrylate binder.

[0020] In some embodiments, the magnesium oxide of the dispersion is characterized by having a surface area ranging from 5-600 m2 / g, such as a surface area ranging from 5 to 200 m2 / g, e.g., from 20 to 200 m2 / g, or from 50 to 200 m2 / g. The present disclosure also relates to magnesium oxide having a surface area of 50-180 m2 / g, 20-30 m2 / g, 50-80 m2 / g, 120-200 m2 / g, or 130-190 m2 / g.

[0021] Preparation of magnesium oxide is usually based on calcination of magnesium carbonate or magnesium hydroxide (obtained by precipitation from brines, or by the Aman process, decomposition of MgCl2»6H2O to give MgO, which is slurried with water to form magnesium hydroxide, followed by separation and calcination). The temperature profile in the calcination kiln influences the properties and activity of the resultant magnesium oxide.

[0022] MgO / Mg(OH)2grades suitable for use in the invention are selected to have a specific surface area from 5-600 m2 / g, such as a surface area ranging from 5 to 200 m2 / g, e.g. from 20 to 200 m2 / g, or from 50 to 200 m2 / g, such as a surface area of 50- 180 m2 / g, 20-30 m2 / g, 50-80 m2 / g, 120-200 m2 / g, or 130-190 m2 / g. Surface areas referred to in the present disclosure are understood to be specific surface areas measured by the BET method (Brunauer-Emmett-Teller method, e.g. using a Quantachrome NOVA e2000 instrument, using a multipoint BET method). Grades meeting the properties set above are readily available on the marketplace (e.g., ICL’s MgO RA40 grade, MgO RA150 grade). The preparation of MgO grades has been disclosed inter alia in WO2021199049. For example, calcination of magnesiumhydroxide at a temperature in the range from 400 to 1100°C for 20 minutes to 2 hours affords magnesium oxide powders with the desired BET surface area.

[0023] The physical properties of MgO grades suitable for use in the invention can be determined based on methods well known in the art, for example as detailed in the Examples below.

[0024] To prepare the composition of the invention, powders of magnesium oxide characterized as described herein, a dispersant, a thickener and optionally a binder are combined in water.

[0025] More specifically, to prepare an aqueous dispersion of MgO, one or more thickeners are mixed with water, followed by the addition of one or more dispersants. MgO powder (e.g., MgO RA150 or RA 40 grade) is then gradually added while stirring continuously for about 30 minutes, such as with the aid of a dissolver stirrer / disperser operating at 300 to 600 revolutions per minute (rpm), on a laboratory scale. Additional thickener may be added if required for viscosity modification. The aqueous dispersion as herein defined may further comprise a binder, e.g., an acrylic binder, which is added last to the dispersion.

[0026] A stable dispersion of MgO in water is formed, with MgO content of not less than 15%, e.g., from 15 to 30% by weight based on the total weight of MgO dispersion such as from 20 to 30% by weight. When present, the concentration of the binder is usually from 3 to 10% by weight. The concentration of the surfactant(s) (e.g., dispersant(s)) is from 0.5 to 1% by weight. The concentration of the thickener is from 0.1 to 0.5% by weight. The MgO dispersion may optionally further comprise a softener and additional textile additives as known in the art.

[0027] Mg(OH)2dispersions can be prepared as described in preparation 5 of WO2021199049.

[0028] It should be understood that the term “aqueous dispersion” (used interchangeably with “aqueous suspension”) for the purpose of the present disclosure means the dispersion of solids (powders) and additives described herein in an aqueous carrier. The aqueous dispersion is usually characterized by aconcentration of solids ranging from 30% by weight to 40% by weight of the total weight of the aqueous dispersion / suspension. The solid content includes all the components of the dispersion except for the aqueous carrier, such as the MgO powder, a binder, a surfactant (e.g., dispersant), etc.

[0029] One or more softening agents (such as ethers and polyglycol esters, ethoxylated products, paraffins, fats orfatty acid condensates) may further be added to the suspension(s) of the present disclosure at the final stage of preparation thereof, at a concentration in the range of 2 to 5% by weight based on the total weight of the MgO aqueous dispersion in each one of the individual suspensions.

[0030] Further textile additives which may be used for preparing the dispersion(s) of the present invention include but are not limited to an anti-foaming agent, a preservative, a dye, a pigment, and any mixture thereof.

[0031] The dispersion(s) as herein defined is / are applicable to any textile product, including but not limited to a medical textile, an article of clothing, a fabric filter, a garment, a diaper, a linen, a decorative textile, a technical textile, a drapery, a carpet, a tent, a sleeping bag, a toy, a wall fabric, a mattress or an upholstery. Examples of articles likely to absorb odorous compounds and develop unpleasant odors (in a manner unrelated to microorganism odor production) include -but are not limited to - aprons, lab coats, sprot clothing, underwear, personal or professional attire.

[0032] In some embodiments the textile product according to the present disclosure is a medical textile product, a facial mask or a fabric filter, sportswear, kitchen cloth, or any kind of clothing.

[0033] In some embodiments the textile product according to the present disclosure is a wearable article such as an apron, a lab coat, sport clothing, underwear, or professional attire.

[0034] In some embodiments the textile product according to the present disclosure is a non-wearable article such as a curtain, a tablecloth, or a fabric bag.

[0035] In some embodiments the BET measured surface area of the MgO is 50-180 m2 / g. and the textile material is made of natural fibers such as cotton.

[0036] In some other embodiments the textile product is made of synthetic fibers such as polyester, and the BET measured surface area of the MgO is 50-180 m2 / g.

[0037] The aqueous dispersion(s) of the present invention comprising MgO are applicable on a variety of textiles (fabric or cloth), woven / knit or non-woven, natural, synthetic or blends thereof, for example textiles / fabrics composed of fibers selected from wool, silk, cotton, nylon, polypropylene, linen, hemp, ramie, jute, acetate, lyocell, acrylic, polyolefin, polyamide, polylactic acid, polyester, rayon, viscose, spandex (also known as elastane, e.g. polyamide-lycra), metallic composite, ceramic, glass, carbon or carbonized composite, and any combination thereof. Exemplary textiles are cotton, polyester, and combination thereof. The amount (percentage) of MgO by weight in the fabric (“add-on”) is determined based on considerations known to a person of skill in the art, based on the fabric type.

[0038] Different fiber types have different surface properties and functional groups which impact the adsorption and retention of volatile compounds. For example, Odor-removal efficiency of a washing process is known to be fiber-dependent, washed polyester exhibits higher odor intensities than washed cotton or wool. This may be due to the presence of hydrophobic or hydrophilic functional groups on the surface of the fibers (cf. Microorganisms 2020, 8, 1709).

[0039] It is thus surprising that the methods and compositions of the present disclosure enable significant odor absorption on both natural and synthetic fibers.

[0040] In another aspect, the present disclosure provides a method for imparting to a textile material absorbability of odorous compounds for neutralizing odors in the textile material, comprising adding a regenerable odor absorbent to said textile material, wherein the absorbent comprises MgO / Mg(OH)2particles having a BET- measured surface area of 5-600 m2 / g at a “dry add-on” level of 0.1 %-2 of MgO / Mg(OH)2calculated based on the treated fabric weight.

[0041] In some embodiments, the MgO / Mg(OH)2particles are added by applying a textile finishing aqueous dispersion comprising water, MgO / Mg(OH)2, a dispersant / surfactant, a thickener, and a binder to the textile, followed by dryingand / or curing. The textile finishing aqueous dispersion may be obtained by diluting a corresponding concentrate containing 10-30% by weight MgO / Mg(OH)2. In any case, the goal is to reach a “dry add-on” level of MgO / Mg(OH)2in the range of 0.1-2%, such as 0.1-1 .8%, such as 0.25-1 .5%, 0.5-1%. As explained above, the type of fabric -wet pick-up rate- are taken into consideration to adjust the loading of MgO / Mg(OH)2as appropriate.

[0042] In addition, we have shown that the odor absorption capacity of MgO / Mg(OH)2particles is regenerated afterwashingthe fabric treated with the subject formulations, for example after 25 wash cycles.

[0043] Textiles can be made odorabsorbing / neutralizing bytreatingorcoatingthereof with the dispersions as described herein, in any industrially acceptable manner, such as padding (a wet finishing process comprising impregnation of the fabric with a formulation / dispersion and subsequently squeezing the fabric between heavy rollers to remove any excess formulation), coating, such as by a knife over roll back coating on one side of the fabric, spraying (or otherwise applying the aqueous dispersions as defined herein onto the textile or fabric). Dip-coated fabrics are generally cured for 3 to 6 minutes at about 120 to 160°C (a thermal process with the purpose of evaporating the solvent and promoting any chemical reactions necessary to fix the finish on the textile / fabric). Other types of fabrics and techniques of treating them with aqueous dispersions as defined herein are described in WO 2016 / 199145.

[0044] The application of the aqueous dispersion(s) as defined herein to the textile can be effected for example during the dyeing or finishing stage of the textile by the manufacturer thereof or at a later stage (e.g., after finalizing the preparation of the textile product).

[0045] As exemplified below, the aqueous dispersion(s) of the present invention is / are added to the textile product or fabric in an amount effective to absorb / neutralize odorous compounds. The resulting textile product includes additives collectively referred to by the term “add-on.” By the term "add-on" level (or percentage) it is meant the total amount of additives (including non-active) loadedonto the treated textile product or fabric; it is calculated based on the difference between the weight of the fabric before and after the treatment / curing (i.e., dried fabric). Adequate odor absorbing properties, namely an odor reduction of 75% or more, preferably 85% or more, preferably 90% or more compared to the untreated fabric, respectively as described in the experimental section below, is achieved with the aid of the MgO aqueous suspension / dispersions as herein defined, at "add-on" levels of 0.1-3% by fabric weight such as an “add-on” level of 0.1-2.5%. When referring to the dry add-on level of MgO / Mg(OH)2, only the magnesium species are taken into account. In such a case, the quantity of magnesium can be measured using tools such as Inductively Coupled Plasma - Optical Emission Spectroscopy (ICP-OES). For example, a piece of treated fabric is sampled and weighed, before being incinerated until only ashes are left. The ashes are then analyzed using ICP- EOS in order to determine the magnesium content. The MgO content is then calculated by multiplying the molar amount of magnesium by the molar mass of MgO. Ultimately, the dry add-on level represents the mass of add-on as measured / calculated divided by the total mass of the treated textile.

[0046] Therefore, a textile product is treated or coated with an odor absorbing / neutralizing finishing aqueous dispersion comprising MgO / Mg(OH)2, a surfactant, a binder, a thickener, as mentioned above, such that after drying and / or curing, the amount of total dry weight added by the dispersion as herein defined to the fabric is 0.1-3%.

[0047] In another aspect, the present disclosure provides a textile product comprising a “dry add-on” level of 0.1 %-2 of MgO / Mg(OH)2calculated based on the mass of magnesium relative to the mass of the textile. This can be measured by incinerating a sample of the textile product and analyzing the ashes by ICP-EOS. For example, the textile product may have a “dry add-on” level of MgO / Mg(OH)2is 0.1- 1.8%, such as 0.25-1 .5%, such as 0.5-1%. The product textile may further comprise anionic acid resin polycarboxylate copolymer, hydroxy ethyl cellulose thickener, and / or acrylic binder.

[0048] In some embodiments, the MgO / Mg(OH)2particles incorporated in the textile product have a BET-measured surface area of 5-200 m2 / g, e.g., 20-200 m2 / g or any other of the ranges specified above.

[0049] For example, the textile product may be is made of cotton, polyester, nylon, or any combination thereof.

[0050] In some embodiments, the textile product is an article wearable by a person exposed to malodorous compounds , such as an apron, a lab coat, sport clothing, underwear, or any personal or professional attire.

[0051] Experimental work conducted in support of this invention demonstrates that an MgO suspension prepared as detailed herein displays an odor reduction effect when padded onto different types of fabric samples, as evident from the examples below.

[0052] The inventors have demonstrated in Examples 1-5 the odor reduction properties of suspensions prepared and applied to fabrics as detailed herein, which contain MgO on various types of fabric (cotton, polyester, etc.) using isovaleric acid, nonenal, and acetic acid as model compounds.

[0053] On a daily basis, many workers are exposed to odorous compounds on their clothing. Therefore, the present aqueous dispersion(s) as herein defined are particularly advantageous as they enable the extension of time between laundry or dry cleaning of any of the relevant products, thus preserving their other properties, such as their color, texture, etc.

[0054] By the term “odor reduction” as used herein it is referred to the lowering of measurability of odorous volatile compounds of a treated fabric compared to untreated fabric.

[0055] The odor-reduction properties of the aqueous dispersions of the present disclosure may be determined by any method known in the art, for example by performing the ISO 17299-3 method. Said ISO 17299-3 method detects and measures any residual amount of a challenge chemical (such as isovaleric acid) in aheadspace vial, after the fabric specimen was exposed to a known amount of said challenge chemical.

[0056] The odor reduction percentage is calculated relatively to a standard solution of the same challenge chemicalthatwas tested without the presence of fabric using the following formula 1 :Formula 1

[0057] The invention will be further described and illustrated by the following examples.Methods and ExamplesOdor Reduction (ORR) Measurement Methods

[0058] The odor reduction was measured using the ISO 17299-3 method (method A) and a modified method B as disclosed below.

[0059] Briefly, the odor measurement method is as follows. a) 3 cm by 3 cm fabric specimen samples are prepared and are placed at the bottom of 20mL headspace (HS) vials (in triplicate). b) The vials containing the specimens as well as empty vials for blank samples are exposed open to a controlled environment of 25°C and 65% humidity overnight. After exposure, the vial screw caps are securely sealed. c) A standard stock solution is prepared in the following way: accurately weigh approximately 36mg of isovaleric acid (IVA) standard into a 10ml volumetric flask. Dissolve and dilute to volume with Diethyl phthalate (DEP). Mix thoroughly to ensure complete dissolution. A concentration of 3.6mg / mL solution is obtained. DEP is used as a blank solution. d) Standard Testing: Using a 5 pL or 10 pL syringe, 5pL of the prepared IVA solution is transferred through the screw-cap septum into the headspace vials. Three replicate vials are prepared for standard testing. The vials are injected under the HS-GC conditions detailed in paragraph

[0069] . The typical retention time of IVA under these conditions is approximately 4.3 minutes. e) Preparation of Specimen forTesting: Using a 5 pL or 10 pL syringe, 5pL of the prepared IVA solution is transferred through the screw-cap septum onto the wall of the exposed headspace vials, avoiding contact with the fabric specimen. f) The blank, triplicate of standard solution, and sample preparations are injected into the chromatograph and the IVA peak in the samples is identified by comparing the retention time with that of the standardsolution. The peak response is recorded while confirming that no interfering peaks appear in the DEP diluent chromatogram. The typical retention time for IVA is about 4.3 minutes. g) Calculation of IVA odor reduction rate: the IVA odor reduction rate is calculated using the following formula 1 for IVA peak areas corresponding to a 0.11 to 3.7 mg / mL range:where ORR is the odor reduction rate, in percentage; Areastd is the average IVA peak area from replicate analyses in the absence of a specimen, AreaSamPie is the average IVA peak area from replicate analyses with a specimen.

[0060] The differences between the ISO measurement method A and the custom method B are disclosed in table 1 below:Table 1

[0061] Exposure to the controlled environment (step b): The controlled environment in ISO method A is 25°C with 65% humidity, while the controlled environment of method B is 100°C in an oven.

[0062] The Gas chromatography parameters used for headspace analysis are summarized in the following table 2:Table 2GC parameters for improved method sensitivityPreparation of Magnesium Oxide Textile Formulations

[0063] Exemplary magnesium oxide textile finishing formulations were prepared according to the following procedure: a) first, water and thickener (such as HEC QP-100MH) were addedb) then the surfactant / dispersant (such as TERSPERSE® 2700) was added to the water and stirred c) MgO powder was gradually added while stirring and stirring was continued for 30 minutes d) if needed a thickener (such as HEC QP-100MH) was added as required for viscosity modification e) The formulation is then diluted with water and applied accordingly in order to obtain dry add-on of~1- 3% on the fabric.The amounts of each component are detailed in table 3 below:Table 3Application of the formulation to textiles

[0064] The exemplary formulations were applied to a variety of textiles using a padcure or a back-coating process. The tested textiles include cotton fabric, polyester fabric, and mixed 65 / 35 polyester cotton fabric.

[0065] Fabric coating (application): fabrics were treated by padding with the formulations (interchangeably referred to as “aqueous dispersions”). Padding was applied by using a padder (Rapid HORIZONTAL PADDING MANGLE-Air-Pad) for impregnating both sides of the fabric, by placing the formulation between the two rolls of the padder and passing the fabric between the two rolls such that the formulation is adsorbed into the fabric, and by squeezing the fabric to the desired moisture content by adjusting the pressure on the rollers. Alternatively, the fabric wascoated by a knife over roll back-coating only one side of the fabric. Coated fabrics were cured at 160°C for 4 minutes and tested according to method A or B.Results

[0066] Sample test results of isovaleric acid absorption on polyester / cotton fabrics treated with the subject formulations are given below:

[0067] Example 1 : Three different formulations using different grades of MgO were tested on mixed 65% polyester / 35% cotton fabric with the following results: Table 4* Natural absorption of 65% polyester / 35% cotton fiber

[0068] These results clearly show the improved absorption of formulation 3 comprising MgO with a 170 m2 / gr surface area.

[0069] Example 2: Three different formulations using different grades of MgO were tested on cotton fabric with the following results: Table 5* Natural absorption of 100% cotton fiber

[0070] These results clearly show the improved absorption of formulations 1 , 2 and 3 comprising MgO with a 25, 70, and 170 m2 / gr surface area.

[0071] Example 3: Three different formulations using different grades of MgO were tested on polyester fabric with the following results: Table 6* Natural absorption of 100% polyester fiber

[0072] These results clearly show the improved absorption of formulations 1 , 2 and 3 comprising MgO with a 25, 70, and 170 m2 / gr surface area.

[0073] It has herein been demonstrated that magnesium oxide absorbs malodor molecules as indicated by standard tests employing body odor molecule analogues such as isovaleric acid, acetic acid and nonenal. We have shown that absorption capacity on fabric is directly and significantly related to the specific surface area of magnesium oxide and identified the variant and add-on to fabric that is most effective yet can be incorporated in an efficient and durable textile finishing formulation.

[0074] It is demonstrated that the odor absorption capacity of magnesia particles is preserved on the fabric treated with the subject formulations, compared to a nontreated fabric, and that a larger surface area magnesia has significantly enhanced performance.

[0075] Although the antibacterial properties of magnesium oxide are known in the art as useful against odor causing bacteria by killing the microbes over a period oftime, we have found that magnesia odor reduction can occur and be useful by direct absorption of odor molecules as they are generated, without need for antibacterial action, provided the magnesia is prepared with a large enough surface area. Moreover, we have found that, during laundry, the magnesia releases the odor molecules to the wash water, and the surface area becomes free again for absorption of new molecules, thus regenerating the odor reduction effect. We have been able to incorporate the large surface area magnesia into a textile finishing formulation that maintains the ability of the magnesia to function as an odor absorber while providing good aesthetics, color fidelity and multi laundry durability.Example 4: Odor absorption after textile wash

[0076] Different types of textiles were treated using the compositions of the invention as disclosed above using HA4-grade MgO (0.5% MgO / Mg(OH)2add-on level). The textiles were then washed multiple times and their odor absorption measured after 50 and 100 wash cycles using ISO 17299-3 - Isovaleric acid (IVA) odor adsorption. The results are tabulated below: Table 7Example 5: Absorption of various compounds

[0077] Different types of textiles were treated using the compositions of the invention as disclosed above using HA4-grade MgO (0.5% MgO / Mg(OH)2add-on level). The textiles were then laundered multiple times, and their odor absorption was measured before and after 25 laundry cycles using ISO 17299-3 odoradsorption with isovaleric acid, nonenal, and acetic acid. The results are tabulated below: fable 8

Claims

Claims1. A method for imparting to a textile material absorbability of odorous compounds for neutralizing odors in the textile material, comprising adding a regenerable odor absorbent to said textile material, wherein the absorbent comprises MgO / Mg(OH)2particles having a BET-measured surface area of 5- 600 m2 / g at a “dry add-on” level of 0.1 %-2 of MgO / Mg(OH)2.

2. The method of claim 1 wherein the MgO particles have a BET-measured surface area ranging from 5 to 200 m2 / g.

3. The method of any one of the preceding claims, wherein the BET measured surface area of the MgO is 20-200 m2 / g.

4. The method of any one of the preceding claims, wherein the BET measured surface area of the MgO is 20-180 m2 / g.

5. The method of any one of claims 1-4, wherein the textile material is made of natural fibers, synthetic fibers, or any combination thereof.

6. The method of claim 5, wherein the textile material is made of cotton and the BET measured surface area of the MgO is 50-180 m2 / g.

7. The method of any claim 5, wherein the textile material is made of polyester and the BET measured surface area of the MgO is 50-180 m2 / g.

8. The method of claim 5, wherein the textile material is made of polyester / cotton blend, and the BET measured surface area of the MgO is 130-190 m2 / g.

9. The method of any one of claims of the previous claims, wherein MgO / Mg(OH)2is added by applying a textile finishing aqueous dispersion comprising water, MgO / Mg(OH)2, surfactant, and thickener to the textile, followed by drying and / or curing.

10. The method of claim 9, wherein the dispersion is provided as a concentrate and wherein the method comprises diluting the concentrate before it is applied to the textile.11 .The method of claim 10 wherein the dispersion concentrate comprises:a. from 60 to 70% by weight of water; b. from 21 to 30% by weight of MgO; c. from 0.5 to 1% by weight of dispersant; d. from 0.1 to 0.5% by weight of thickener; and e. from 3 to 10% by weight of a binder.

12. The method of any one of the previous claims wherein the “dry add-on” level of MgO / Mg(OH)2is 0.1-1.8%, such as 0.25-1 .5%.

13. An odor neutralizing textile finishing aqueous dispersion concentrate comprising: a. from 60 to 70% by weight of water; b. from 21 to 30% by weight of MgO; c. from 0.5 to 1% by weight of polycarboxylate dispersant, d. from 0.1 to 0.5% by weight of cellulose thickener; and optionally e. from 3 to 10% by weight of binder.

14. The dispersion of claim 13, comprising: a. 65-66% water, b. 26-27% MgO, c. 0.6-0.7% polycarboxylate dispersant, d. 0.35-0.45% cellulose thickener, and e. 6-7% binder.

15. The dispersion of any one of claim 13-14, wherein the thickener hydroxy ethyl cellulose (HEC), the dispersant is an anionic acid resin polycarboxylate copolymer, and / or the binder is an acrylate binder.

16. The dispersion of any one of claims 13-15 wherein the MgO has a BET- measured surface area of 5-600 m2 / g.

17. A textile product comprising a “dry add-on” level of 0.1 %-2 of MgO / Mg(OH)2.

18. The textile product of claim 17 wherein the “dry add-on” level of MgO / Mg(OH)2is 0.1-1.8%, such as 0.25-1 .5%.

19. The textile product of claim 17 further comprises anionic acid resin polycarboxylate copolymer, hydroxy ethyl cellulose thickener, and / or acrylic binder.

20. The textile product of any one of claims 17-19 wherein the MgO / Mg(OH)2has a BET-measured surface area of 20-200 m2 / g.21 .The textile product any one of claims 17-20 wherein the textile is made of cotton, polyester, nylon, or any combination thereof.

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