Method for detecting invisible stains on fabric

Abstract

A method for detecting invisible stains on fabric is provided.

Description

【Technical Field】 【0001】 The present invention relates to a method for detecting invisible stains on fabrics. 【Background Art】 【0002】 As detergent products have evolved, consumers' needs regarding cleaning have been sufficiently met. However, in the field of laundry, there are still some other unmet consumer needs. Specifically, one of the unsolved problems is that most clothing becomes greyer / darker and less colorful after the period of use. Although the laundry looks very clean after washing, it does not look as new and colorful as the original. That is, over time, the clothes look "old". 【0003】 The reasons underlying the problems mentioned above are very complex. Without wishing to be bound by theory, one of the important reasons is thought to be the presence of some invisible stains that accumulate inside the gaps of the fabric or thread, or even penetrate into the fibers of the clothing and cannot be easily removed during the washing process. Such invisible stains are often located deep inside the fabric, strongly attached to the fibers, inside the small serrations of the fibers, or inside the internal pores of the fibers. These cannot be easily seen by consumers or by analytical devices. Therefore, it is very difficult to detect such invisible stains. Therefore, it is also difficult to evaluate whether these invisible stains are removed during the washing process. Without wishing to be bound by theory, invisible stains that are not removed by washing often become a problem over time due to other deteriorations such as oxidation or heat, and often ruin the clothing. 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 Therefore, there is a need to develop a method for detecting invisible stains. [Means for solving the problem] 【0005】 In one aspect, the present invention relates to a method for detecting invisible stains on fabric, wherein the method is A) A process of providing fabric with invisible stains attached, B) The process includes measuring the transmittance whiteness index of the fabric under a transmitted light source. 【0006】 In some embodiments, a method for detecting invisible stains on fabric is, A) A process of providing fabric with invisible stains attached, B1) By using a spectrometer under a transmitted light source, the transmitted whiteness index (i.e., TWI) of the fabric before washing can be determined. before The process of measuring ) and B2) A step of washing the fabric with a detergent composition, B3) By using a spectrometer under a transmitted light source, the transmitted whiteness index (i.e., TWI) of the fabric after washing can be determined. after The process of measuring ) and B4) This includes the step of calculating ΔTWI using the following formula. TWI after -TWI before =ΔTWI 【0007】 In some embodiments, a method for detecting invisible stains on fabric is, A) A process of providing fabric with invisible stains attached, B1) By using a spectrometer under a transmitted light source, the transmitted whiteness index (i.e., TWI) of the fabric before washing can be determined. before By measuring the reflectance whiteness index (i.e., RWI) of the fabric before washing, using a spectrometer under a reflected light source, the RWI index of the fabric is determined. before The process of measuring ) and B2) A step of washing the fabric with a detergent composition, B3) By using a spectrometer under a transmitted light source, the transmitted whiteness index (i.e., TWI) of the fabric after washing can be determined. afterMeasuring [[ID=]], and by using a spectrometer under a reflected light source, the reflected whiteness index of the fabric after washing (i.e., RWI after ), and B4) calculating ΔTWI and ΔRWI according to the following formula, may be included. TWI after -TWI before = ΔTWI, and RWI after -RWI before = ΔRWI 【0008】 The method for detecting invisible stains according to the present disclosure has the advantages of being simple and easy to use. Specifically, the method for detecting invisible stains according to the present disclosure can provide results consistent with sensory tests. 【0009】 In another aspect, the present invention is a method for washing a fabric, comprising: A) providing a fabric with invisible stains attached; B) treating the fabric with a detergent composition containing a surfactant system of about 1 wt% to about 70 wt% of the composition, wherein the surfactant system contains about 51 wt% to about 100 wt% of an anionic surfactant, the treating step. 【0010】 In one embodiment according to the present application, the surfactant system may further contain about 1 wt% to about 49 wt% of a nonionic surfactant of the surfactant system. 【0011】 In another embodiment according to the present application, the weight ratio of the anionic surfactant to the nonionic surfactant may be 1.05 to 10, preferably 1.1 to 5, more preferably 1.15 to 3, for example, 1.1, 1.5, 2, 3, or any range therebetween. 【0012】 In another embodiment of this application, the detergent composition may further contain about 0.05% to about 15% by weight, preferably about 0.1% to about 5% by weight, more preferably about 0.2% to about 3% by weight of a polyalkylene oxide graft copolymer, the polyalkylene oxide graft copolymer is a) A polyalkylene oxide component as a graft base having a number-average molecular weight of 1,000 to 20,000 daltons and based on ethylene oxide, propylene oxide, butylene oxide, or a mixture thereof, b) Polyvinyl esters are derived from saturated monocarboxylic acids and / or methyl or ethyl esters of acrylic acid or methacrylic acid containing 1 to 6 carbon atoms, and the polyvinyl ester component as a side chain, c) containing polyvinylpyrrolidone as a side chain, The weight ratio of (a):(c) is 1:0.1 to 1:2. By weight, the quantity of (a) is greater than the quantity of (b). 【0013】 In one embodiment of the present application, in the graft polymer, a) the polyalkylene oxide copolymer comprises ethylene oxide units or ethylene oxide units and propylene oxide units, preferably consisting of ethylene oxide units or ethylene oxide units and propylene oxide units, and b) the polyvinyl ester comprises vinyl acetate, preferably consisting of vinyl acetate. 【0014】 In one embodiment of the present application, in the graft copolymer, the polyalkylene oxide has a number-average molecular weight of 2,000 to 15,000 Daltons, and / or the weight ratio of (a):(b) is 1.0:0.1 to 1.0:0.99, preferably 1.0:0.3 to 1.0:0.9, and / or the polyalkylene oxide graft polymer has a weight-average molecular weight of 4,000 Da to 100,000 Da. 【0015】 In one embodiment of this application, the composition may further preferably comprise processing aids selected from the group consisting of surfactants, fatty acids and / or salts thereof, enzymes, encapsulating beneficial agents, stain-releasing polymers, colorants, builders, chelating agents, stain transfer inhibitors, dispersants, enzyme stabilizers, antioxidants, catalytic materials, bleaching agents, bleaching catalysts, bleaching activators, polymer dispersants, stain removers / anti-redeposition agents, polymer grease cleaners, amphiphilic copolymers, glossing agents, antifoaming agents, dyes, colorants, fragrances, encapsulated fragrances, structural elastoides, fabric softeners, carriers, fillers, hydrotropes, solvents, antimicrobial agents and / or preservatives, neutralizing agents and / or pH adjusters, processing aids, rheological adjusters and / or structuring agents, opacifiers, pearl essences, pigments, corrosion inhibitors and / or colorfast agents, and mixtures thereof. 【0016】 In one embodiment of this application, the composition may be in the form of a liquid composition, a granular composition, a single-compartment pouch, a multi-compartment pouch, a sheet, a pastille or beads, a fibrous article, a tablet, a bar, a flake, or a mixture thereof. 【0017】 In one embodiment of this application, the detergent composition is: Approximately 2% to 20% by weight of C6 to C in the detergent composition 20 LAS and Approximately 0% to 10% by weight of C6 to C in the detergent composition 20 AES and Approximately 0% to 10% by weight of C6 to C in the detergent composition 20 AS, Approximately 2% to 20% by weight of C in the detergent composition 12 ~C 18 Alkyl ethoxylate and The detergent composition contains approximately 0.2% to approximately 3% by weight of a graft copolymer, The weight ratio of anionic surfactants to nonionic surfactants is 1.15 to 2.5. 【0018】 In some embodiments, the fabrics treated by the washing method according to this disclosure are The ΔRWI of the fabric, when measured according to Test 1: Whiteness Index Test, is -5 to 5, preferably -3 to 3, for example -3, -2, -1, 0, 1, 2, 3, or any range in between, and / or The ΔTWI of the fabric may be characterized by being -5 to 5, preferably -3 to 3, for example, -3, -2, -1, 0, 1, 2, 3, or any range in between, when measured according to Test 1: Whiteness Index Test. 【0019】 In another embodiment, the present invention relates to a method for washing fabric, i) A process of providing fabric with invisible stains attached, ii) A step of treating a fabric with a detergent composition comprising about 0.05% to about 15% by weight, preferably about 0.1% to about 5% by weight, more preferably about 0.2% to about 3% by weight of a polyalkylene oxide graft copolymer, wherein the polyalkylene oxide graft copolymer is a) Polyalkylene oxide components as a graft base, b) Polyvinyl ester components as side chains, and / or c) The present invention relates to a method comprising a processing step including polyvinylpyrrolidone as a side chain. [Modes for carrying out the invention] 【0020】 definition When used herein, articles such as "a" and "an" are understood to mean one or more of the claims or descriptions when used in the claims. 【0021】 As used herein, the terms “comprise,” “comprises,” “comprising,” “include,” “includes,” “including,” “contain,” “contains,” and “containing” are non-limiting, meaning that other processes and other components that do not affect the final result may be added. The terms “consist of” and “essentially consist of.” 【0022】 As used herein, when a composition is "substantially free" of a particular component, it means that the composition contains that particular component in amounts less than trace, alternatively less than 0.1% by weight of the composition, alternatively less than 0.01% by weight, or alternatively less than 0.001% by weight. 【0023】 As used herein, the term “laundry detergent composition” means a composition for washing soiled materials, including fabrics. Such compositions may be used as pre-washing agents, post-washing agents, or added during the rinse or wash cycle of a laundry operation. Laundry detergent compositions may be in a form selected from liquids, powders, unit doses such as single-compartment or multi-compartment unit doses, pouches, tablets, gels, pastes, bars, or flakes. Preferably, laundry detergent compositions are liquids or unit-dose compositions. As used herein, the term “liquid laundry detergent composition” means a composition in a form selected from the group consisting of pourable liquids, gels, creams, and combinations thereof. Liquid laundry detergent compositions may be either aqueous or non-aqueous, and may be anisotropic, isotropic, or a combination thereof. As used herein, the term “unit-dose laundry detergent composition” means a water-soluble pouch containing a specific amount of liquid enclosed in a water-soluble film. 【0024】 As used herein, the term "alkyl" means a hydrocarbyl moiety that is branched or unbranched, substituted or unsubstituted. The term "alkyl" includes the alkyl moiety of an acyl group. 【0025】 As used herein, the term “major surfactant” refers to a surfactant present in a composition in a larger amount than any other surfactant contained in such a composition. Similarly, the term “major anionic surfactant” refers to an anionic surfactant present in a composition in a larger amount than any other anionic surfactant contained in such a composition. 【0026】 As used herein, the term “majority surfactants” refers to surfactants present in a composition in an amount that is at least 50% by weight of the total surfactant content in such composition. Similarly, the term “majority anionic surfactants” refers to anionic surfactants present in a composition in an amount that is at least 50% by weight of the total anionic surfactant content in such composition. 【0027】 As used herein, the term “cleaning solution” refers to a typical amount of aqueous solution used for one cycle of laundry, preferably 1 to 50 liters, or alternatively, 1 to 20 liters for manual washing or 20 to 65 liters for machine washing. 【0028】 As used herein, the term “textile” is used non-specifically and may refer to any type of natural or artificial fiber, including cotton, recycled cotton, synthetic modified cotton, linen, wool, polyester, nylon, elastane, silk, acrylic, and similar materials, as well as various blends and combinations. 【0029】 As used herein, the term “invisible stain” means any stain that is present on a fabric but is not visible to the naked eye under normal use conditions. More specifically, an invisible stain is any stain present on a fabric that is not visible to an observer positioned on the same side of the fabric as the light source (e.g., sunlight or a D65 standard light source). More specifically, an invisible stain is any stain present on a fabric that is visible to an observer positioned on the opposite side of the fabric from the light source (e.g., sunlight or a D65 standard light source), but not visible to an observer positioned on the same side of the fabric as the light source. Specifically, an invisible stain may have dimensions of micrometer size (e.g., 1 to 500 micrometers, preferably 1 to 100 micrometers, more preferably 1 to 50 micrometers, most preferably 1 to 20 micrometers). In some embodiments, an invisible stain may include stains that are deposited within the fabric or strongly adhered to the fibers or within the internal pores of the fibers. Preferably, invisible stains may include sweat stains, urine stains, desquamed skin cells, scales, sebum, sugars, polysaccharides, guar, or any combination thereof that is deposited in the fabric or strongly adhered to the fibers or within the internal pores of the fibers. 【0030】 As used herein, the term “transmitted light source” means a light source located on the opposite side of the fabric from the observer. Preferably, the transmitted light source is a D65 light source. In some embodiments, TWI is measured by using a spectrometer under conditions that the D65 light source is on the opposite side of the fabric from the observer and forms an observation angle of 10°. 【0031】 As used herein, the term “reflected light source” means a light source located on the same side of the fabric as the observer. Preferably, the reflected light source is a D65 light source. In some embodiments, RWI is measured by using a spectrometer under conditions that the D65 light source is on the same side of the fabric as the observer and makes an observation angle of 10°. 【0032】 composition The compositions of this disclosure may be selected from the group consisting of detergent powder compositions, lightweight liquid detergent compositions, heavy liquid detergent compositions, detergent gels commonly used in laundry, bleaching compositions, laundry additives, fabric strengthening compositions, unit dose articles, and mixtures thereof. 【0033】 The composition may be in any preferred form. The composition may be in the form of a liquid composition, a granular composition, a single-compartment pouch, a multi-compartment pouch, a sheet, a scented tablet or beads, a fibrous article, a tablet, a bar, a flake, or a mixture thereof. The composition may be liquid, solid, or a combination thereof. 【0034】 The composition may be an aqueous liquid laundry detergent composition. In such an aqueous liquid laundry detergent composition, the water content may be at a level of 5.0% to 95% by weight of the liquid detergent composition, preferably 25% to 90% by weight, and more preferably 50% to 85% by weight. 【0035】 The pH range of the detergent composition may be 2.5 to 9, for example, 3.0 to 5.0, 4.0 to 7.0, 6.0 to 8.9, preferably pH 7 to 8.8. 【0036】 The detergent composition can also be encapsulated in a water-soluble film to form a unit-dose article. Such a unit-dose article comprises the detergent composition of the present invention, the detergent composition comprising less than 20% by weight, preferably less than 15% by weight, and more preferably less than 10% by weight of water, and the detergent composition is encapsulated in a water-soluble or water-dispersible film. Such a unit-dose article can be formed using any means known in the art. A preferred unit-dose article may include one compartment, which contains the liquid laundry detergent composition. Alternatively, a unit-dose article may be a multi-compartment unit-dose article in which at least one compartment contains the liquid laundry detergent composition. 【0037】 Polyalkylene oxide graft copolymer The detergent composition may contain one or more polyalkylene oxide graft copolymers. The graft copolymer may be present in the composition at levels of about 0.01% to about 15% by weight, preferably about 0.05% to about 10% by weight, more preferably about 0.1% to about 5% by weight, most preferably about 0.2% to about 3% by weight, for example, at levels of 0.10% by weight, 0.15% by weight, 0.20% by weight, 0.25% by weight, 0.30% by weight, 0.35% by weight, 0.40% by weight, 0.45% by weight, 0.50% by weight, 1% by weight, 2% by weight, or 3% by weight. 【0038】 In certain embodiments, the polyalkylene oxide graft copolymer comprises (a) a polyalkylene oxide having a number-average molecular weight of 1,000 to 20,000 daltons and based on ethylene oxide, propylene oxide, and / or butylene oxide; (b) a polyvinyl ester component as a side chain; and (c) polyvinylpyrrolidone as a side chain. Specifically, the polyvinyl ester component is derived from saturated monocarboxylic acids and / or methyl or ethyl esters of acrylic acid or methacrylic acid containing 1 to 6 carbon atoms. 【0039】 In certain embodiments, the weight ratio of component a) to component b) is 1:0.1 to 1:0.99, preferably 1:0.3 to 1:0.9. 【0040】 In certain embodiments, the weight ratio of component a) to component c) is 1:0.1 to 1:2, preferably 1:0.3 to 1:1. 【0041】 In certain embodiments, in the polyalkylene oxide graft copolymer, 1.0 mol% to 60 mol%, preferably 20 mol% to 60 mol%, and more preferably 30 mol% to 50 mol%, of the grafted monomer of component (b) is hydrolyzed. 【0042】 In certain embodiments, the polyalkylene oxide comprises ethylene oxide units or ethylene oxide units and propylene oxide units. 【0043】 In certain embodiments, the polyvinyl ester includes vinyl acetate. 【0044】 Suitable polyalkylene oxides can be obtained based on homopolymers or copolymers, with homopolymers being preferred. Suitable polyalkylene oxides may be based on homopolymers of ethylene oxide or ethylene oxide copolymers having an ethylene oxide content of 40 mol% to 99 mol%. Suitable comonomers for such copolymers include propylene oxide, n-butylene oxide, and / or isobutylene oxide. Suitable copolymers include copolymers of ethylene oxide and propylene oxide, copolymers of ethylene oxide and butylene oxide, and / or copolymers of ethylene oxide, propylene oxide, and at least one butylene oxide. The copolymers may contain an ethylene oxide content of 40 to 99 mol%, a propylene oxide content of 1.0 to 60 mol%, and a butylene oxide content of 1.0 to 30 mol%. The graft base may be linear (linear) or branched, for example, a branched homopolymer and / or a branched copolymer. 【0045】 Branched copolymers can be prepared by adding ethylene oxide, with or without propylene oxide and / or butylene oxide, to a polyhydric low molecular weight alcohol, such as trimethylolpropane, pentose, or hexose. 【0046】 Alkylene oxide units can exist internally as blocks, even if they are randomly distributed within the polymer. 【0047】 The polyalkylene oxide of component (a) may be the corresponding polyalkylene glycol in its free form (i.e., having an OH terminal group), or one or both terminal groups may be protected. Preferred terminal groups may be, for example, C1-C25 alkyl groups, phenyl groups, and C1-C14 alkylphenyl groups. The terminal group may be a C1-alkyl (e.g., methyl) group. Suitable materials for the graft base include polyethylene glycols such as PEG1000, PEG2000, PEG4000, PEG6000, PEG8000, PEG10000, PEG12000, and / or PEG20000, and / or monomethoxypolyethylene glycols such as MPEG2000, MPEG4000, MPEG6000, MPEG8000, and MEG10000, which are commercially available from BASF under the trade name PLURIOL, and / or PE6100, PE6800, or PE3100, which are commercially available from BASF under the trade name PLURONIC. These block copolymers are made from ethylene oxide-propylene oxide-ethylene oxide (EO-PO-EO) or propylene oxide-ethylene oxide-propylene oxide (PO-EO-PO). 【0048】 Polyalkylene oxides can be grafted with N-vinylpyrrolidone as the monomer of component (b). While we do not wish to be bound by theory, it is believed that the presence of N-vinylpyrrolidone ("vinylpyrrolidone, VP") monomer in the graft copolymer according to this disclosure results in water solubility and good film-forming properties compared to other similar polymers that do not contain N-vinylpyrrolidone monomer. The repeating unit of vinylpyrrolidone is amphiphilic due to a polar amide group that can form a dipole and a nonpolar moiety with a methylene group that makes the backbone and ring hydrophobic. 【0049】 Polyalkylene oxides can be grafted with vinyl esters as monomers for component (c). Vinyl esters can be derived from saturated monocarboxylic acids that may contain 1 to 6 carbon atoms, 1 to 3 carbon atoms, 1 to 2 carbon atoms, or 1 carbon atom. Preferred vinyl esters can be selected from the group consisting of vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl isovalerate, vinyl caproate, or mixtures thereof. Preferred monomers for component (c) include those selected from the group consisting of vinyl acetate, vinyl propionate, or mixtures thereof, and are preferably vinyl acetate. 【0050】 Traditionally, molecular weight is expressed by the "K value" obtained from relative viscosity measurements. Graft copolymers can have K values ​​of 5.0 to 200, and optionally 5.0 to 50, measured according to H. Fikentscher in a 2% strength solution in dimethylformamide at 25°C. 【0051】 A particularly preferred graft copolymer of the present invention has a polyethylene oxide backbone grafted with one or more polyvinyl acetate side chains. More preferably, the weight ratio of the polyethylene oxide backbone to the polyvinyl acetate side chains is in the range of about 1:0.2 to about 1:10, or about 1:0.5 to about 1:6, most preferably about 1:1 to about 1:5. An example of such a preferred amphiphilic graft copolymer is the Sokalan® HP22 polymer, commercially available from BASF Corporation. This polymer has a polyethylene oxide backbone grafted with polyvinyl acetate side chains. The polyethylene oxide backbone of this polymer has a number-average molecular weight (Mn) of about 6,000 g / mol (corresponding to about 136 ethylene oxide units), and the weight ratio of the polyethylene oxide backbone to the polyvinyl acetate side chains is about 1:3. The number-average molecular weight (Mn) of the polymer itself is about 13,000 g / mol. 【0052】 Surfactant-based The compositions according to this disclosure may contain a surfactant system in an amount of 1% to 99% by weight, preferably 4% to 80% by weight, preferably 6% to 50% by weight, more preferably 10% to 30% by weight, for example, 5% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 60% by weight, 70% by weight, 80% by weight, 90% by weight, or any range in between. Specifically, the surfactant system may include anionic surfactants and nonionic surfactants. 【0053】 Specifically, anionic surfactants may include linear alkylbenzene sulfonate (LAS), alkyl ethoxylated sulfate (AES), alkyl sulfate (AS), methyl ester sulfonate (MES), alkyl ether carboxylate (AEC), or any combination thereof. Preferably, the anionic surfactant is C6-C6. 20 Linear alkylbenzene sulfonate (LAS), C6~C 20 Alkyl ethoxylated sulfate (AES), C6-C 20 The material is selected from the group consisting of alkyl sulfates (AS) and any combination thereof. 【0054】 Specifically, nonionic surfactants may include alkylalkoxylated alcohols, alkylalkoxylated phenols, alkyl polysaccharides, polyhydroxy fatty acid amides, alkoxylated fatty acid esters, and any combination thereof. Preferably, the nonionic surfactant is selected from nonionic surfactants represented by formula (1). R 12 -X-[(EO) s (PO) t ]-R 13 ...(1) In the formula, R 12 is a linear or branched alkyl group having 8 to 18 carbon atoms, X is -O or -C(O)O-, and R 13 is an alkyl group having hydrogen or 1 to 6 carbon atoms, s represents the average repeat of EO, t represents the average repeat of PO, s is 3 to 20, t is 0 to 6, EO represents ethylene oxide, PO represents propylene oxide, and EO and PO may be arranged in a mixture. 【0055】 Suitable anionic surfactant systems for the compositions of the present invention are C6-C 20 Linear alkylbenzene sulfonate (LAS), C6~C 20 Alkyl sulfate (AS), C6~C 20 Alkylalkoxysulfates (AAS), C6-C 20 Methyl ester sulfonate (MES), C6-C 20 Alkyl ether carboxylates (AECs) and any combination thereof may be selected from the group. For example, laundry detergent compositions may be C6-C 20 Alkylalkoxysulfate (AA x S) [wherein x is about 1 to 30, preferably about 1 to 15, more preferably about 1 to 10, most preferably about 1 to 3] may contain such AA x The alkyl chain in S can be either linear or branched, and medium-chain branched AA x S surfactants are particularly preferred. Preferred group AA x For S, x is approximately 1 to 3. 12 ~C 14 Examples include alkyl alkoxy sulfates. In some embodiments, the composition contains 1% to 30% by weight, preferably 2% to 25% by weight, more preferably 3% to 20% by weight, for example, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, or any range in between, an anionic surfactant. 【0056】 Suitable nonionic surfactant systems for the composition may be selected from the group consisting of alkylalkoxylated alcohols, alkylalkoxylated phenols, alkyl polysaccharides, polyhydroxy fatty acid amides, alkoxylated fatty acid esters, sucrose esters, sorbitan esters and alkoxylated derivatives of sorbitan esters, and any combination thereof. Non-limiting examples of nonionic surfactants suitable for use herein include C, such as the Neodol® nonionic surfactant available from Shell. 12 ~C 18 Alkyl ethoxylate; C6~C 12 Alkylphenol alkoxylates (where the alkoxylate unit is a mixture of ethylene oxy units and propylene oxy units); C with ethylene oxide / propylene oxide block alkyl polyamine ethoxylates such as Pluronic® available from BASF. 12 ~C 18 Alcohol and C6~C 12 Alkylphenol condensate; C 14 ~C 22 Examples of medium-chain branched alkyl alkoxylates (BAEx, where x is approximately 1 to approximately 30); alkyl polysaccharides, specifically alkyl polyglycosides; polyhydroxy fatty acid amides; and ether-terminated poly(oxyalkylated) alcohol surfactants. Furthermore, nonionic surfactants as used herein include alkoxylated ester surfactants, for example, those of formula R 1 C(O)O(R2O)nR 3 [In the formula, R 1 These are linear and branched C6-C 22 Selected from alkyl or alkylene moieties, R 2 It is selected from the C2H4 and C3H6 portions, R 3Alkoxylated ester surfactants having [where is selected from H, CH3, C2H5, and C3H7 moieties, and n has a value of about 1 to about 20] are also useful. Examples of such alkoxylated ester surfactants include aliphatic methyl ester ethoxylates (MEEs), which are well known in the art. In some specific embodiments, the alkoxylated nonionic surfactant contained in the laundry detergent composition of the present invention is C6-C 20 Alkoxylated alcohols, preferably C8-C 18 Alkoxylated alcohols, more preferably C 10 ~C 16 It is an alkoxylated alcohol. C6~C 20 The alkoxylated alcohol is preferably an alkylalkoxylated alcohol with an average alkoxylated degree of about 1 to about 50, preferably about 3 to about 30, more preferably about 5 to about 20, and even more preferably about 5 to about 9. In some embodiments, the composition contains 1% to 30% by weight, preferably 2% to 25% by weight, more preferably 3% to 20% by weight, for example, 4%, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, or any range in between these amounts of a nonionic surfactant. 【0057】 The ratio of anionic surfactant to nonionic surfactant may be 0.01 to 100, preferably 0.05 to 20, more preferably 0.1 to 10, and most preferably 0.2 to 5. 【0058】 In some embodiments, the anionic surfactant is C6-C 20 Linear alkylbenzene sulfonate surfactant (LAS), preferably C 10 ~C 16 LAS, and moreover C 12 ~C 14 Includes LAS. In other embodiments, the anionic surfactant is C6-C 20Alkyl alkoxy sulfate (AAS), preferably C 10 ~C 16 AAS, ferC 12 ~C 14 Contains AAS. In other embodiments, the anionic surfactant is C6-C 20 Alkyl sulfate (AS), preferably C 10 ~C 16 AS, more preferably C 12 ~C 14 Includes AS. 【0059】 In some specific embodiments of the present invention, anionic surfactants may be present in the composition as the main surfactant, preferably as the majority surfactant. Preferably, the ratio of anionic surfactants to nonionic surfactants may be 1.05 to 100, preferably 1.1 to 20, more preferably 1.2 to 10, and most preferably 1.3 to 5. Specifically, the anionic surfactant is C6 to C 20 It may contain linear alkylbenzene sulfonates (LAS). 【0060】 In some specific embodiments of the present invention, a nonionic surfactant may be present in the composition as the main surfactant, preferably as the majority surfactant. Preferably, the ratio of anionic surfactant to nonionic surfactant may be 0.01 to 0.95, preferably 0.05 to 0.9, more preferably 0.1 to 0.85, and most preferably 0.2 to 0.8. Specifically, the nonionic surfactant is C6 to C 20 It may contain alkoxylated alcohols. 【0061】 The laundry detergent composition of the present invention may further contain a cationic surfactant. Non-limiting examples of cationic surfactants include quaternary ammonium salt surfactants (which may have up to 26 carbon atoms and include alkoxylate quaternary ammonium (AQA) surfactants), dimethylhydroxyethyl quaternary ammonium compounds, dimethyldiisopropyl quaternary ammonium compounds, dimethylhydroxyethyl laurylammonium chloride, polyamine cationic surfactants, and amine surfactants, specifically amidopropyldimethylamine (APA). 【0062】 The laundry detergent composition of the present invention may further contain an amphoteric surfactant. Non-limiting examples of amphoteric surfactants include amine oxides, derivatives of secondary and tertiary amines, derivatives of heterocyclic secondary and tertiary amines, or derivatives of quaternary ammonium, quaternary phosphonium, or tertiary sulfonium compounds. Preferred examples include C6-C 20 Examples of betaines include alkyldimethylamine oxide, alkyldimethyl betaine and cocodimethylamidopropyl betaine, sulfo and hydroxybetaine (alkyl group is C8-C8). 18 or C 10 ~C 14 Possible candidates include N-alkyl-N,N-dimethylamino-1-propanesulfonate. 【0063】 Other ingredients The laundry detergent compositions according to this disclosure may further contain 0.01% to 10% by weight, preferably 0.1% to 5% by weight, more preferably 0.2% to 3% by weight, and most preferably 0.3% to 2% by weight of a surfactant-enhancing polymer, preferably polyvinyl acetate grafted polyethylene oxide copolymer, in an amount of the composition. 【0064】 The laundry detergent compositions described herein may contain auxiliary components. Suitable auxiliary substances include, but are not limited to, builders, chelating agents, rheological modifiers, color transfer inhibitors, dispersants, enzymes and enzyme stabilizers, antioxidants, catalytic materials, bleach activators, hydrogen peroxide, hydrogen peroxide sources, pre-formed peracids, polymer dispersants, clay stain removers / anti-redeposition agents, whitening agents, antifoaming agents, dyes, photobleaching agents, fragrances, fragrance microcapsules, structural elastoides, fabric softeners, carriers, hydrotropes, processing aids, solvents, colorants, structuring agents, and / or pigments. The exact properties and concentrations of these auxiliary components in the laundry detergent composition depend on the physical form of the composition and the nature of the washing operation in which the composition is used. 【0065】 In some embodiments, the laundry detergent compositions according to the present disclosure may further contain 0.01% to 10% by weight, preferably 0.1% to 5% by weight, more preferably 0.2% to 4% by weight, most preferably 0.3% to 3% by weight, for example, 0.5% by weight, 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, or any range thereof, of fatty acids. 【0066】 Preparation of composition The laundry detergent compositions of the present invention are generally prepared by conventional methods known in the art of the manufacture of laundry detergent compositions. Such methods typically involve mixing essential components and optional components in any desired order to a relatively homogeneous state, with or without the application of heating, cooling, vacuum, etc., thereby providing a laundry detergent composition containing the components at the required concentrations. 【0067】 How to use Another aspect of the present invention relates to a method for using a laundry detergent composition for treating fabrics. Such a method can provide the benefit of removing invisible stains from fabrics. The method comprises the step of administering 5g to 120g of the laundry detergent composition mentioned above into a washing tub containing water to form a cleaning solution. The amount of cleaning solution in the washing tub according to this specification is preferably 1L to 65L, alternatively 1L to 20L for manual washing and 10L to 65L for machine washing. The temperature of the laundry cleaning solution is preferably in the range of 5°C to 60°C. 【0068】 In some embodiments, the composition is added to the washing machine via a dispenser (e.g., a dispensing drawer). In some other embodiments, the composition is added to an automatic dispensing washing machine via an automatic dispensing mechanism. In some other embodiments, the composition is added directly to the washing machine drum. In some other embodiments, the composition is added directly to the washing solution. 【0069】 The dosage in the methods described herein may vary depending on the type of washing. In one embodiment, the method involves dispensing about 5 g to about 60 g of the laundry detergent composition into a manual washing tub (e.g., about 2 to 4 L). In an alternative embodiment, the method involves dispensing about 5 g to about 100 g, preferably about 10 g to about 65 g, of the laundry detergent composition into a washing machine (e.g., about 10 to 45 L). 【0070】 Test method Test 1: Whiteness Index Test To determine the whiteness index, a titanium dioxide deposition test is performed using a Tergotometer (Model: RHLQ IV, manufactured by China Daily Chemical Industry Research Institute) as follows: TiO2 (100-300nm, available from Shanghai (Meryer) Biochemical Technology Co., Ltd.): 2g per 1L of tap water Body dirt (JB03, available from Sino Light Inspection & Certification Co. Ltd.): 6g in 1L of tap water (optional) Water amount: 1L Type of water: Tap water HDL concentration: 3000ppm Fabric tracer: Three 10cm x 10cm pieces of glossy CW98 (100% heavy cotton, purchased from Danxin Textile Co. Beijing, China), or three 10cm x 10cm pieces of glossy PCW13 (100% heavy cotton, purchased from Danxin Textile Co. Beijing, China), or one 10cm x 10cm piece of non-glossy CW11 (100% heavy cotton, purchased from Danxin Textile Co. Beijing, China), pre-striped six times in DI water with China National Standard powder detergent (Taiyuan, made in China). According to the following titanium dioxide deposition test method, before washing, the L of the fabric tracer * ab is measured (and then RWI before (Calculate ΔE as specified), opacity Y(TWI before It calculates (which is called). 1. Add tap water. 2. Add HDL and dissolve for 3 minutes. 3. Add the mixture of titanium dioxide and JB03 and dissolve for 3 minutes. 4. Add the fabric tracer and start agitation (main wash). 5. The main washing time is 5 minutes. 6. Remove the fabric from the washing container, wring it out, and let it dry. 7. Add tap water, insert the fabric tracer, and start stirring (rinse). 8. The rinsing time is 2 minutes. 9. Repeat steps 7 and 8 until the stain is completely rinsed out and no residue remains. 10. Remove the fabric from the rinse container and let it air dry. 11. Using Polaris * Measure A / B and RWI afterCalculate the specified ΔE and use Hunter color to TWI after The opacity Y, which was specified as such, was measured. 12. Measurement of reflected light: Polaris; Measurement of transmitted light: Hunter color 13. Calculate ΔTWI and ΔRWI using the following formulas. TWI after -TWI before =ΔTWI, and RWI after -RWI before =ΔRWI 【0071】 Test 2: Whiteness Grade Test Data The titanium dioxide deposition test will be conducted using a Tergotometer (Model: RHLQ IV, manufactured by China Daily Chemical Industry Research Institute), similar to Test 1. The Reflected Whiteness Grade (RWG) will be determined by five panelists who will observe the whiteness of the test sample and the reference sample under reflective light conditions after washing. Scores will be given from -2 to 2, where a negative number indicates that the panelists rate the test sample highly compared to the reference sample, a positive number indicates that the panelists rate the test sample highly, and a score of 0 indicates no difference between the samples. 【0072】 The Transmitted Whiteness Grade (TWG) was determined by five panelists who, after washing, observed the whiteness of the test sample compared to a reference sample under transmitted light conditions. Scores ranging from -2 to 2 were assigned, where a negative number indicated a higher rating from the panelist compared to the reference sample, a positive number indicated a higher rating from the panelist compared to the test sample, and a score of 0 indicated no difference between the samples. Specifically, during observation, six pieces of fabric were stacked for each sample and covered with a flashlight as a transmitted light source. 【0073】 [Table 1] [Examples] 【0074】 Synthesis Example 1: Synthesis of Graft Copolymers A graft copolymer of PVP / PVAc-g-PEG in a weight ratio of 20:30:50 and having a weight-average molecular weight of 16,800 daltons was prepared as follows. 【0075】 In a polymerization vessel equipped with a stirrer and reflux condenser, 720 g of PEG (6000 g / mol) and 60 g of 1,2-propanediol (MPG) were initially added under a nitrogen atmosphere. The mixture was homogenized at 70°C. 【0076】 Next, 432 g of vinyl acetate (after 2 hours), 288 g of vinylpyrrolidone in 576 g of MPG (after 5 hours), and 30.2 g of tert-butyl perpivalate in 196.6 g of MPG (after 5.5 hours) were weighed and added. After the feed was completely added, the solution was stirred at 70°C for 1 hour. Then, 3.8 g of tert-butyl perpivalate in 25.0 g of MPG (after 1.5 hours) was weighed and added, followed by stirring for 0.5 hours. 【0077】 Volatile substances were removed by vacuum stripping. Then, 676.8 g of deionized water was added, and steam distillation was performed at 100°C for 1 hour. 【0078】 The temperature of the reaction mixture was reduced to 80°C, and 160.6 g of sodium hydroxide aqueous solution (50%, each containing 40 mol% VAc) was added at the maximum feed rate. After the sodium hydroxide solution was completely added, the mixture was stirred at 80°C for 1 hour, and then cooled to ambient temperature. 【0079】 The resulting graft copolymer is characterized by a K value of 24. The solids content of the final solution is 45%. 【0080】 Example 1: Establishment of a method for detecting invisible stains To establish a method for detecting invisible stains on fabrics, two sample liquid laundry detergent compositions containing the following components were prepared. 【0081】 [Table 2] 【0082】 It is known that the measured ΔRWI can indicate overall cleaning performance (i.e., overall stain removal), with a higher ΔRWI indicating poor cleaning performance and a lower ΔRWI indicating better cleaning performance. Surprisingly, the inventors found that the transmitted whiteness index (e.g., ΔTWI) under a transmitted light source, measured according to Test 1: Whiteness Index Test, is useful for evaluating the performance of invisible stain removal. A higher ΔTWI indicates poor invisible stain removal, while a lower ΔTWI indicates improved invisible stain removal. 【0083】 To evaluate whether this method could function, an analytical test was conducted according to Test 1: Whiteness Index Test (with titanium dioxide added without body stains), and a sensory test was conducted according to Test 2: Whiteness Grade Test. ΔRWI and ΔTWI were measured for samples 1 and 2 according to Test 1: Whiteness Index Test (with titanium dioxide added without body stains), with PCW13 (whitening agent-containing polycotton) and CW98 (whitening agent-containing cotton) used as white fabric tracers. 【0084】 The inventors have found that consumers can notice stains invisible under transmitted light, for example, when looking at the sun through a fabric, but such invisible stains are indistinguishable under typical reflected light. In Test 2, TWG is a direct subjective measurement of whiteness under transmitted light. Therefore, if the analytical parameters have the same trend as TWG, those analytical parameters may be useful measurements for removing invisible stains. The results shown in Table 2 show that ΔTWI measured according to Test 1: Whiteness Index Test is in complete agreement with TWG measured according to Test 2: Whiteness Grade Test. Therefore, ΔTWI is a good indicator for removing invisible stains. 【0085】 Specifically, in analytical testing, Sample 1 and Sample 2 exhibit very similar ΔRWI (i.e., overall visible stain removal is similar between Sample 1 and Sample 2). Consistently, the sensory test scores for Samples 1 and 2 are close to zero (i.e., RWG is -0.6 and -0.4), meaning there is no significant difference between them. On the other hand, under transmitted light, Sample 2 exhibits a much lower ΔTWI compared to Sample 1 in analytical testing (3.3 vs. 7.7 and -0.2 vs. 4.8), and Sample 2 also shows better sensory scores for whiteness compared to Sample 1 in sensory testing (+1.4 and +2.0). Furthermore, the data indicate that laundry detergent compositions containing anionic surfactants as the primary surfactant (e.g., Sample 2) are more efficient in removing invisible stains than laundry detergent compositions containing nonionic surfactants as the primary surfactant (e.g., Sample 1), although overall stain removal is similar between them. 【0086】 [Table 3] 【0087】 Example 2: Improved removal of invisible stains in a laundry detergent composition containing polyalkylene oxide graft copolymer. Two sample liquid laundry detergent compositions containing the following components were prepared. Sample 3 contained a polyalkylene oxide graft copolymer, while Sample 4 did not contain such a graft copolymer. 【0088】 [Table 4] 1. A polyalkylene oxide graft copolymer according to Synthesis Example 1, having a weight-average molecular weight of 16,800 daltons and a weight ratio of PVP / PVAc-g-PEG of 20:30:50. 【0089】 The ΔTWI of samples 3 and 4 was measured according to Test 1: Whiteness Index Test (with titanium dioxide added along with body stains). Sample 3, which contains the graft copolymer, shows significantly improved removal of invisible stains compared to sample 4, which does not contain such a graft copolymer, as shown in Table 5 below. 【0090】 [Table 5] 【0091】 The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​listed. Instead, unless otherwise specified, each such dimension is intended to mean both the listed value and the functionally equivalent range encompassing that value. For example, a dimension disclosed as "40 mm" is intended to mean "approximately 40 mm." 【0092】 All documents referenced herein, including any patents or patent applications that are cross-referenced or related, and any patent applications or patents on which this application claims priority or benefit thereof, are incorporated herein by reference in their entirety, unless expressly excluded or otherwise limited. No reference to any document shall be deemed prior art to any invention disclosed or claimed herein, nor shall any such invention be taught, suggested, or disclosed, either alone or in combination with any one or more other references. Furthermore, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in any document incorporated by reference, the meaning or definition given to that term in this document shall prevail. 【0093】 While specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications within the scope of the invention be covered in the appended claims.

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