Methods of washing fabrics

Abstract

The present invention relates to a method for washing fabrics, wherein the method comprises the following steps: (a) in a main wash step, washing stained fabrics with an aqueous wash bath, the aqueous wash bath comprising a detersive surfactant and a photobleach; and (b) in a rinse step, rinsing the stained fabrics with an aqueous rinse solution, the aqueous rinse solution comprising perfume, wherein during at least a part of the main wash step (a), an artificial light source is present and switched on, and provides light to the wash liquor in such a way as to activate the photobleach present in the wash liquor, and wherein during at least a part of the rinse step (b), the artificial light source is switched off, and the artificial light source does not provide any light to the aqueous rinse solution.

Description

Technical Field

[0001] The present invention relates to a method for washing fabrics. The method is a washing process that provides good cleaning performance, especially for soils that cause malodors. Background Art

[0002] The benefits of using photosensitive components in laundry treatment compositions have been described in the prior art, for example, improved stain removal, or elimination of microorganisms such as bacteria and spores.

[0003] The problem in the prior art is the effective and uniform activation of the photosensitive components in the washing solvent (e.g., water). When the activating light source is provided as a fixed arrangement in the washing machine, it will only activate the photosensitive components near the fixed source, which means that the laundry washing products and the washing solvent (e.g., water) need to be thoroughly agitated to ensure uniform exposure to the light source.

[0004] Another problem in the art is protecting detergent ingredients such as perfumes, hueing dyes, brighteners and enzymes from oxidative degradation by light activated photocatalysts. Summary of the invention

[0005] The present invention provides a method for washing fabrics, wherein the method comprises the following steps:

[0006] (a) washing the soiled fabrics in a main wash step with an aqueous wash bath comprising a detersive surfactant and a photobleach; and

[0007] (b) in a rinsing step, rinsing the soiled fabric with an aqueous rinse solution comprising one or more of the following components: perfume, brightener, hueing dye, enzyme, and any combination thereof.

[0008] wherein during at least a portion of the main wash step (a) an artificial light source is present and switched on and provides light to the wash liquor in such a manner as to activate a photo-bleach present in the wash liquor, and wherein during at least a portion of the rinse step (b) the artificial light source is switched off and does not provide any light to the aqueous rinse solution. DETAILED DESCRIPTION

[0009] Methods of washing fabrics

[0010] The method of washing fabrics comprises the following steps:

[0011] (a) washing the soiled fabrics in a main wash step with an aqueous wash bath comprising a detersive surfactant and a photobleach; and

[0012] (b) in a rinsing step, rinsing the soiled fabric with an aqueous rinse solution comprising one or more of the following components: perfume, brightener, hueing dye, enzyme, and any combination thereof.

[0013] wherein an artificial light source is present and switched on during at least a part of said main wash step (a) and said artificial light source provides light to said wash liquor in such a way as to activate a photo-bleach present in said wash liquor,

[0014] And wherein during at least a portion of said rinsing step (b) said artificial light source is turned off and said artificial light source does not provide any light to said aqueous rinse solution.

[0015] Typically, the method is performed in an automatic washing machine. Typically, the artificial light source is a light source present in the washing drum of the automatic washing machine.

[0016] The method can be used to provide whiteness and freshness benefits to laundered fabrics.

[0017] Step (a), main washing step

[0018] In the main wash step (step (a)), the soiled fabrics are washed with an aqueous wash bath comprising a detersive surfactant and a photobleach.

[0019] An artificial light source is present and switched on during at least a portion of the main wash step (a) and provides light to the wash liquor in such a way that the photo-bleach present in the wash liquor is activated. It may be preferred that the artificial light source is switched on for the majority of the main wash step (a). It may even be preferred that the artificial light source is switched on for the entire main wash step (a).

[0020] Step (b), rinsing step

[0021] In the rinsing step (step (b)), the soiled fabric is rinsed with an aqueous rinse solution comprising one or more of the following components: perfume, brightener, hueing dye, enzyme, and any combination thereof.

[0022] The artificial light source is turned off during at least a portion of the rinsing step (b) and does not provide any light to the aqueous rinsing solution. Preferably, the artificial light source is turned off for most of the rinsing step (b). It may even be preferred that the artificial light source is turned off for the entire rinsing step (b).

[0023] Photobleach

[0024] The photobleaching agent typically comprises a photosensitive moiety selected from the group consisting of xanthone, xanthene, thioxanthone, thioxanthene, phenothiazine, fluorescein, benzophenone, alloxazine, isoalloxazine, flavin, phthalocyanine, derivatives thereof, and any combination thereof.

[0025] Preferably, the photobleach is selected from the group consisting of: riboflavin; fluorescein B; erythrosine; a salt of any of these photobleaches; a derivative of any of these photobleaches; and any combination thereof.

[0026] It may be preferred to:

[0027] (a) the photobleaching agent is thioxanthone, and wherein the artificial light source provides light with a wavelength of 300 nm to 400 nm;

[0028] (b) the photobleaching agent is riboflavin, and wherein the artificial light source provides light with a wavelength of 400 nm to 480 nm;

[0029] (c) the photobleaching agent is fluorescein B, and wherein the artificial light source provides light with a wavelength of 460 nm to 570 nm;

[0030] (d) the photobleaching agent is erythrosine, and wherein the artificial light source provides light with a wavelength of 460 nm to 550 nm; and / or

[0031] (e) The photobleaching agent is a phthalocyanine derivative, and wherein the artificial light source provides light with a wavelength of 550 nm to 750 nm.

[0032] Aqueous cleaning bath

[0033] The aqueous wash bath is typically formed by contacting a laundry detergent with water. The laundry detergent typically comprises a detersive surfactant and a photobleach.

[0034] Rinse solution

[0035] The rinse solution may contain perfume. It may be preferred that the rinse solution contains other chemicals that are incompatible with the photobleach, for example chemicals that may be unstable in the presence of the photobleach. Such chemicals may include enzymes, hueing dyes and / or brighteners.

[0036] Additionally, the rinse solution may contain chemicals that provide benefits to fabrics during the rinsing step. Such chemicals may include fabric softeners.

[0037] The rinse solution may comprise a hueing dye. The rinse solution comprises a brightener. The rinse solution comprises a fabric softener.

[0038] The rinse solution is typically formed by contacting the fabric enhancer with water. The fabric enhancer typically includes a perfume.

[0039] Artificial light

[0040] Typically, the artificial light source is present in the washing drum of an automatic washing machine. Preferably, the artificial light source is provided by one or more LEDs, or two or more LEDs, or three or more LEDs, or even four or more LEDs. Preferably, the artificial light source is provided by one or more light bulbs, or two or more light bulbs, or three or more light bulbs, or even four or more light bulbs.

[0041] Typically, an artificial light source is present and switched on during at least a portion of the main wash step (a) and provides light to the wash liquor in such a way as to activate the photo-bleach present in the wash liquor. The artificial light source is preferably switched on for most of the duration of the main wash step (a), and may be switched on for the entire main wash step (a).

[0042] During at least a portion of the rinsing step (b), the artificial light source is turned off, and the artificial light source does not provide any light to the aqueous rinsing solution at this time. For most of the duration of the rinsing step (b), the artificial light source may be turned off, and for the entire rinsing step (b), the artificial light source may be turned off, and the artificial light source does not provide any light to the aqueous rinsing solution at this time.

[0043] Most of the time means more than 50%, or even more than 60%, or even more than 70%, or even more than 80%, or even more than 90% of the step time.

[0044] The artificial light source may comprise two or more, or three or more, or even four or more LEDs.

[0045] It may be preferred that the artificial light source emits diffuse light.

[0046] Diffuse light is defined as light with a beam spread of 46° to 130° or more, which corresponds to beam types 4 to 7 according to the NEMA (National Electrical Manufacturers Association) beam spread classification (cf. Table 4).

[0047]

[0048] Table 4. NEMA beam spread classification

[0049] Laundry detergent

[0050] The aqueous wash liquors useful herein may contain one or more detersive surfactants, generally including, but not limited to, anionic surfactants, nonionic surfactants, cationic surfactants, zwitterionic surfactants, amphoteric surfactants, and combinations thereof.

[0051] The anionic surfactants useful in practicing the present invention can themselves be of several different types. For example, water-soluble salts of higher fatty acids (i.e., "soaps") are anionic surfactants useful in aqueous washing liquids herein. This includes alkali metal soaps, such as sodium, potassium, ammonium and alkylammonium salts of higher fatty acids containing from about 8 to about 24 carbon atoms, and preferably from about 12 to about 18 carbon atoms. Soaps can be made by direct saponification of fats and oils, or by neutralization of free fatty acids. Particularly useful are sodium and potassium salts of mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium soaps of tallow and coconut oil. Additional non-soap anionic surfactants suitable for use herein include water-soluble salts, preferably alkali metal and ammonium salts, of organic sulfuric acid reaction products having an alkyl group containing from about 10 to about 20 carbon atoms and a sulfonic acid or sulfate ester group in its molecular structure (the term "alkyl" includes the alkyl portion of the acyl group). Examples of such synthetic anionic surfactants include, but are not limited to: a) sodium, potassium and ammonium alkyl sulfates having linear or branched carbon chains, especially those obtained by sulfating higher alcohols (C 10 -C 20carbon atoms), such as those produced by reducing the glycerides of tallow or coconut oil; b) sodium, potassium and ammonium alkyl ethoxy sulfates having a linear or branched carbon chain, especially those wherein the alkyl group contains from about 10 to about 20, preferably from about 12 to about 18 carbon atoms, and wherein the ethoxylated chain has an average degree of ethoxylation ranging from about 0.1 to about 5, preferably from about 0.3 to about 4, and more preferably from about 0.5 to about 3; c) sodium and potassium alkyl benzene sulfonates wherein the alkyl group is a linear or branched carbon chain. chain configuration, preferably containing about 10 to about 20 carbon atoms in a straight chain carbon chain configuration; d) sodium alkyl sulfonates, potassium alkyl sulfonates and ammonium alkyl sulfonates, wherein the alkyl group contains about 10 to about 20 carbon atoms in a straight chain or branched chain configuration; e) sodium alkyl phosphates or phosphonates, potassium alkyl phosphates or phosphonates and ammonium alkyl phosphates or phosphonates, wherein the alkyl group contains about 10 to about 20 carbon atoms in a straight chain or branched chain configuration; and f) sodium alkyl carboxylates, potassium alkyl carboxylates and ammonium alkyl carboxylates, wherein the alkyl group contains about 10 to about 20 carbon atoms in a straight chain or branched chain configuration, and combinations thereof. Particularly preferred for use in the practice of the present invention is a surfactant system comprising C10-C20 linear alkylbenzene sulfonate (LAS) and C10-C20 linear or branched unalkoxylated alkyl sulfate (AS). Preferred for use in the practice of the present invention is a LAS surfactant, as described above. LAS may be present in the pretreatment composition or in a subsequently added fabric treatment composition in an amount sufficient to form an aqueous wash liquor containing from about 100 ppm to about 2000 ppm, preferably from about 200 ppm to about 1500 ppm, more preferably from about 300 ppm to about 1000 ppm of LAS.

[0052] The aqueous washing liquid may contain (as an alternative to LAS or in combination with LAS) one or more AS surfactants, as described above. The AS surfactant may be present in the aqueous washing liquid in an amount ranging from about 100 ppm to about 2000 ppm, preferably from about 200 ppm to about 1500 ppm, more preferably from about 300 ppm to about 1000 ppm.

[0053] The aqueous washing liquid may also contain one or more C10-C20 linear or branched alkyl alkoxylated sulfates (AAS) having an average degree of ethoxylation in the range of from about 0.1 to about 5, preferably from about 0.3 to about 4, and more preferably from about 0.5 to about 3. Such AES surfactants may be present therein in an amount in the range of from about 0 ppm to about 1000 ppm, preferably from about 0 ppm to about 500 ppm, more preferably from about 0 ppm to about 300 ppm.

[0054] In addition, the aqueous wash liquor may contain from about 0 ppm to about 1000 ppm, preferably from about 0 ppm to about 500 ppm, more preferably from about 0 ppm to about 200 ppm of a nonionic surfactant. Preferred nonionic surfactants are those having the formula R 1 (OC2H4) n OH, where R1 is C 10 -C 20 alkyl group or alkylphenyl group, and n is from about 1 to about 80. Particularly preferred are C 10 -C 20 Alkyl alkoxylated alcohol (AA).

[0055] Other surfactants useful herein include amphoteric surfactants and cationic surfactants. Such surfactants are well known for use in laundry detergents and are typically present in an amount of from about 10 ppm to about 300 ppm, preferably from about 15 ppm to about 200 ppm, more preferably from about 20 ppm to about 100 ppm.

[0056] The aqueous wash liquor of the present invention may also contain one or more adjunct ingredients commonly used in formulating laundry detergent compositions, such as builders, fillers, carriers, structurants or thickeners, clay soil removal / anti-redeposition agents, polymeric soil removers, polymeric dispersants, polymeric grease cleaners, enzymes, enzyme stabilization systems, amines, bleaching compounds, bleaching agents, bleach activators, bleach catalysts, brighteners, dyes, hueing agents, dye transfer inhibitors, chelating agents, softeners or conditioning agents (such as cationic polymers or silicones), perfumes (including perfume encapsulates), sanitizing and malodor treatment agents, etc. Preferably, the aqueous wash liquor of the present invention is substantially free of any fabric softeners.

[0057] Aqueous rinse solution

[0058] The aqueous rinse solution comprises one or more of the following components: perfume, brightener, hueing dye, enzyme, and any combination thereof.

[0059] The rinse solution of the present invention may consist essentially of water, or of deionized water or tap water. The rinse solution may contain one or more fabric care agents selected from the group consisting of fabric softeners, surface modifiers, anti-wrinkle agents, perfumes, and the like. For example, the aqueous rinse solution of the present invention may contain a fabric softener in an amount ranging from about 10 ppm to about 2000 ppm, preferably from about 20 ppm to about 1500 ppm, more preferably from about 50 ppm to about 1000 ppm. Preferably, the fabric softener is a cationic compound, such as a quaternary ammonium compound, a cationic silicone, a cationic starch, a smectite clay, and combinations or derivatives thereof. More preferably, it is a diester quaternary ammonium compound of formula (I):

[0060] {R4-m-N+-[(CH2)nY–R5]m}A-(I)

[0061] Wherein each R is independently selected from hydrogen, short chain C1-C6, poly(C2-C3 alkoxy), benzyl, and mixtures thereof; m is 2 or 3; each n is independently 1 to 4; each Y is independently -O-(O)C- or -C(O)-O-; the sum of the carbons in each R5 may be C11-C21, wherein each R5 is independently a hydrocarbon group or a substituted hydrocarbon group; and A- is a softener compatible anion.

[0062] Preferably, in formula (I), each R is independently selected from C1-C3 alkyl; m is 2; each n is independently 1 to 2; each Y is independently -O-(O)C- or -C(O)-O-; the sum of carbons in each R5 may be C12-C20, wherein each R5 is independently a hydrocarbyl or substituted hydrocarbyl group; and A- is selected from chloride, bromide, methyl sulfate, ethyl sulfate, sulfate or nitrate. More preferably, the fabric softener is a bis-(2-hydroxyethyl)-dimethylammonium chloride fatty acid ester, preferably, the average chain length of the fatty acid portion is 16 to 20 carbon atoms, preferably 16 to 18 carbon atoms. Alternatively, the fabric softener may be a cationic siloxane, such as a polydimethylsiloxane polymer containing at least one quaternized nitrogen atom.

[0063] The aqueous rinse solution herein may contain other substances, non-limiting examples of which include surfactants, solvents, salts (e.g., CaCl), acids (e.g., HCl and formic acid), preservatives, and water. Preferably, the aqueous rinse liquid of the present invention is substantially free of the anionic surfactants and nonionic surfactants described above for aqueous wash liquids, and more preferably, it is substantially free of any surfactant.

[0064] Example

[0065] All experiments were conducted using 5 cm x 5 cm knitted cotton samples (Warwick Equest, Ltd.). Each knitted cotton sample was pretreated with skatole before washing experiments were performed. For this purpose, a solution was prepared by adding the required amount of skatole to isopropanol to reach a concentration of 0.0025 g / mL. Next, a 10 mL aliquot of this solution was added to each knitted cotton sample (samples were used within 10 minutes from the addition of skatole).

[0066] All washing experiments were performed by introducing 6 knitted cotton swatches pre-treated with skatole in a glass jar containing 50 mL of wash liquor. The wash liquor had been prepared by dissolving 3 g of the desired liquid detergent formulation (formulation A or B described in Table 1) in 1.5 L of city water.

[0067] In comparative washing process (experiments 1 and 2 in table 2), jar is placed in the light box with lights off for 40 minutes, and manually stirred every 2 minutes.Then, take out 10mL aliquot from jar, and discard the remainder of washing liquid, while knitted cotton sample is left in jar.Next, 40mL city water, 10mL aliquot previously taken and the perfume solution of the required volume reaching 12.5ppm concentration are added in the jar containing knitted cotton sample, to simulate the rinse stage of washing cycle.10mL aliquot is added back in jar, enters the rinse stage with the detergent autonomous washing that repeats to occur in washing machine.Next, jar is introduced again in the light box with lights off for 30 minutes, and manually stirred every 2 minutes (by gently shaking flask 5 times with clockwise rotation).Finally, 4mL washing liquid is transferred in GCMS (gas chromatography mass spectrometry) bottle, to assess head space. Two comparative washing processes were carried out using the previously described experimental procedures using the detergent formulations of composition A and composition B respectively described in Table 1 .

[0068] Table 1

[0069]

[0070]

[0071] The same experimental procedure described previously for the comparative wash process was performed, followed by a wash process (Experiments 3-6 in Table 2) but in this case the light was turned on during the main wash and / or rinse phase as described in Table 2. Each of the wash processes was performed using a detergent formulation having either Composition A or Composition B as described in Table 1.

[0072] Table 2

[0073] experiment Washing light Rinsing light Detergent composition (Table 1) 1 no no A 2 no no B 3 yes yes A 4 yes yes B 5 yes no A 6 yes no B

[0074] Table 3 shows the headspace levels of fragrance and malodor expressed as the percentage of headspace remaining after the wash cycle.It can be observed that in the comparative wash processes (Experiments 1 and 2) there was zero malodor reduction after washing the textiles regardless of the detergent composition used.

[0075] It can be observed that while Experiments 4 and 6 showed the best malodor reduction benefit (post-wash traces), it was also with the lights off during the rinse cycle that provided the best perfume performance (Experiment 6).

[0076] Table 3

[0077]

[0078]

[0079] The dimensions and values ​​disclosed herein are not to be understood as being strictly limited to the exact numerical values ​​cited. Instead, unless otherwise indicated, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

Claims

1. A method for washing fabrics, wherein the method comprises the following steps: (a) washing soiled fabrics in a main wash step with an aqueous wash bath comprising a detersive surfactant and a photobleach; as well as (b) in a rinsing step, rinsing the soiled fabric with an aqueous rinse solution comprising one or more of the following components: perfume, brightener, hueing dye and enzyme, wherein an artificial light source is present and switched on during at least a part of said main wash step (a) and provides light to said wash liquor in such a way as to activate said photo-bleaching agent present in said wash liquor, And wherein during at least a portion of said rinsing step (b) said artificial light source is turned off and said artificial light source does not provide any light to said aqueous rinse solution.

2. The method of claim 1, wherein the method is performed in an automatic washing machine and the artificial light source is a light bulb present in a washing drum of the automatic washing machine.

3. The method according to claim 1, wherein the photobleach is selected from the group consisting of: riboflavin; fluorescein B; erythrosine; a salt of any of these photobleaches; a derivative of any of these photobleaches; and any combination thereof.

4. The method according to claim 1, wherein: (a) the photobleaching agent is thioxanthone, and wherein the artificial light source provides light with a wavelength of 300 nm to 400 nm; (b) the photobleaching agent is riboflavin, and wherein the artificial light source provides light with a wavelength of 400 nm to 480 nm; (c) the photobleaching agent is fluorescein B, and wherein the artificial light source provides light with a wavelength of 460 nm to 570 nm; (d) the photobleaching agent is erythrosine, and wherein the artificial light source provides light with a wavelength of 460 nm to 550 nm; and / or (e) The photobleaching agent is a phthalocyanine derivative, and wherein the artificial light source provides light with a wavelength of 550 nm to 750 nm.

5. The method of any one of claims 1 to 4, wherein the rinse solution comprises a hueing dye.

6. The method according to any one of claims 1 to 4, wherein the rinse solution comprises a whitening agent.

7. The method of any one of claims 1 to 4, wherein the rinse solution comprises a fabric softener.

8. The method according to any one of claims 1 to 4, wherein the artificial light source comprises two or more light bulbs.

9. The method according to any one of claims 1 to 4, wherein the artificial light source emits diffuse light.

10. Use of a method according to any preceding claim for providing whiteness and freshness benefits to laundered fabrics.

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