Components for washing solid goods.

Abstract

The present invention relates to a solid laundry composition for reducing malodour. Particularly, the present invention relates to a solid laundry detergent composition; that ensures that the fabric surface remains fresh and free of malodours. This is ensured by using a composition comprising a surfactant, select polysaccharide and a hydrotrope.

Description

[0001] A SOLID LAUNDRY COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to a solid laundry composition for reducing malodour. Particularly, the present invention relates to a fabric treatment composition such that the surface remains fresh and free of malodour.

[0004] Background of the Invention

[0005] Washing fabrics, also known as laundering or simply as laundry, makes up one of the main chores that people undertake routinely. For this, people have been relying on detergent compositions that are widely available. Typically, a fabric is washed by contacting it with a detergent composition either in neat or diluted form, rinsing the fabric one or more times with water; and finally, drying it. In the washing step, a fabric is cleaned by mechanically agitating it using hands and / or by using suitable cleaning means e.g. a brush, in so-called hand-wash method. Alternatively, in so-called machine-wash method, a fabric is cleaned by mechanical agitations carried out by a machine. In either case, a step of soaking a fabric, in a neat or diluted detergent composition, may be carried out for a desired duration e.g. 30 to 60 minutes. The step of drying may also be carried out by using machines; or simply by exposing the fabric to air, and if possible, under the sun.

[0006] During the rinsing steps, which may be with fresh water two or three times, often a fabric conditioning composition is added especially in the final rinse step to provide various benefits like anti yellowing, fabric conditioning, or antimicrobial benefits. Fabric conditioners were generally developed to deliver certain surface treatments to the fabric to ensure they are soft, smooth and free of static. The present invention relates to a composition that could be included in either the wash step or the rinsing step for delivering the benefit of reducing dank odours.

[0007] Drying of the fabric may be carried out in a machine at high temperature (e.g. 50 to 80 °C) with flow of air in which case the step may be carried out for half hour to about two hours. This is considered as fast drying in which case the high temperature ensures quick removal of water and inactivation of residual odour causing microorganisms. Machine drying is energy intensive and is popular only in cold and rainy countries where there is continuous supply of power to run such machines. In hot countries like in the tropical areas with high amount of sunshine the washed fabric is dried in the sun on clotheslines. Such a drying process often taken several hours. Depending on the season e.g. the rainy season or unavailability of outdoor space to dry the fabric in the sun, the drying is much slower and may sometimes take two or three days to dry. Under such drying conditions the clothes acquire a dank odour. Including a fabric treatment composition (containing high amount of perfume) during the rinse step does not seem to solve the problem to an adequate amount. The present inventors are aware that microorganisms like Moraxella osloensis and Staphylococcus hominis are responsible for producing the malodour when fabric are present under these high - moisture conditions.

[0008] The present inventors in seeking to solve the above problem have hit upon a solution which involves formulating a solid laundry composition comprising a surfactant, select polysaccharide and a hydrotrope. Such compositions were found to deliver the desired benefit of reducing malodour.

[0009] It is therefore an object of the present invention to provide for a solid laundry composition that provides malodour benefits on the washed fabric especially when they are dried under slow drying conditions or could only be dried to a high moisture content.

[0010] Summary of the Invention

[0011] The first aspect of the present invention relates to a solid laundry composition for reducing malodour comprising

[0012] (i) 0.01 to 5 wt% a polysaccharide selected from one or more of algin, pectin, dextrin or resistant dextrin;

[0013] (ii) 0.1 to 5 wt% a hydrotrope selected from one or more of sodium cumene sulphonate, sodium xylene sulphonate, polyethylene glycol and mono propylene glycol; and

[0014] (iii) a surfactant.

[0015] Another aspect of the present invention relates to a method of reducing malodour from a laundry surface comprising the step of contacting the surface with a composition of the first aspect preferably diluted with water followed optionally with the step of rinsing the surface with water.

[0016] Detailed Description of the Invention

[0017] For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of” or "composed of'. Thus, the term "comprising" is meant not to be limiting to any subsequently stated elements, but rather to optionally also encompass nonspecified elements of major or minor functional importance. In other words, the listed steps or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word "about". Unless specified otherwise, numerical ranges expressed in the format "x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as “wt%”.

[0018] The composition of the invention comprises a polysaccharide selected from one or more of algin, pectin, dextrin or resistant dextrin.

[0019] Alginic acid, also called algin, is a polysaccharide distributed widely in the cell walls of brown algae that is hydrophilic and forms a viscous gum when hydrated. Alginic acid is a linear copolymer with homopolymeric blocks of (1— >4)-linked p-D-mannuronate (M) and a-L- guluronate (G) residues, respectively, covalently linked together in different sequences or blocks. The monomers may appear in homopolymeric blocks of consecutive G-residues (G-blocks), consecutive M-residues (M-blocks) or alternating M and G-residues (MG-blocks). a-L-guluronate is the C-5 epimer of p-D-mannuronate. Alginates are refined from brown seaweeds. Throughout the world, many of the Phaeophyceae class brown seaweeds are harvested to be processed and converted into sodium alginate and alginic acid.

[0020] Pectin is a structural acidic heteropolysaccharide contained in the primary and middle lamella and cell walls of terrestrial plants. Its main component is galacturonic acid, a sugar acid derived from galactose. It is produced commercially as a white to light brown powder, mainly extracted from citrus fruits, and is used in food as a gelling agent, particularly in jams and jellies. It is also used in dessert fillings, medicines, sweets, as a stabiliser in fruit juices and milk drinks, and as a source of dietary fiber. Pectin also known as pectic polysaccharides, are rich in galacturonic acid. Several distinct polysaccharides have been identified and characterised within the pectic group. Homogalacturonans are linear chains of a-(1-4)-linked D-galacturonic acid. Substituted galacturonans are characterised by the presence of saccharide appendant residues (such as D-xylose or D-apiose in the respective cases of xylogalacturonan and apiogalacturonan) branching from a backbone of D-galacturonic acid residues. Rhamnogalacturonan pectins (RG- I) contain a backbone of the repeating disaccharide: 4)-a-D-galacturonic acid-(1 ,2)-a-L- rhamnose-(1. From many of the rhamnose residues, sidechains of various neutral sugars branch off. The neutral sugars are mainly D-galactose, L-arabinose and D-xylose, with the types and proportions of neutral sugars varying with the origin of pectin. Another structural type of pectin is rhamnogalacturonan II (RG-II), which is a less frequent, complex, highly branched polysaccharide.

[0021] Pectin is the preferred first polysaccharide for inclusion in the composition of the invention. Pectin when included is preferably derived from one or more of a fruit chosen from pear, apple, guava, plum, gooseberry, orange or any other citrus fruit, preferably citrus. It is preferably from apple or citrus fruit.

[0022] Pectin consists predominantly of a-D galacturonic acid units, but also contains some amount of neutral sugars such as rhamnose, xylose, arabinose, galactose and glucose.

[0023] The percentage of galacturonic acid units is therefore the amount of galacturonic acid groups present relative to the total amount of the pectin. The galacturonic acid content of a sample can be determined by methods known in the art, such as for example the Saeman hydrolysis method (Englyst and Cummings (Analyst, 109(7), 937-942 (1984), Filisetti-Cozzi and Carpita (Analytical Biochemistry, 197, 157-162 (1991)).

[0024] Galacturonic acid typically has the following repeat unit structure:

[0025] It is possible to esterify galacturonic acids on the carboxylic acid group. The percentage of esterified units is called the degree of esterification (DE). The degree of esterification can be determined according to methods known in the art, such as the base titration method (Shultz, 1965) as proposed by the Food Chemical Codex (FCC (1981). 3rd ed., (1981) National Academy of Science, Washington, DC), quantification of methanol released during de-esterification using gas chromatography (GC) (Walter et al. (1983), Journal of Food Science, 48: 1006-10070), colorimetry (Hou et al. (1999), Botanical Bulletin of Academia Sincia, 40:115-119), high performance liquid chromatography (HPLC) (Levigne S., et al. (2002), Food Hydrocolloids 16: 547-550), nuclear magnetic resonance (NMR) (Rosenbohm et al. (2003) Carbohydrate Research, 338: 637-649) and capillary zone electrophoresis (CZE) (Williams et al. (2003), Journal of Agricultural Food and Chemistry, 51 : 1777-1781).

[0026] A method to separate pectin into fractions with different DE is described, for example, by Strom, et al. (2005), Carbohydrate Polymers, Volume 60, Issue 4, 20 June 2005, Pages 467-473.

[0027] In nature, the carboxylic groups are typically methylated to varying degrees to provide pectin methyl esters. The number fraction of carboxylic acid groups methylated is known as the degree of methyl esterification.

[0028] The pectin used in the composition of the present invention preferably has a degree of methyl esterification higher than 50%, more preferably 52.5% or higher, further more preferably 55% or higher, yet more preferably 57.5% or higher and most preferably 60% or higher.

[0029] The pectin used according to the invention preferably has a molecular weight of higher than 50kDa, more preferably higher than 100kDa. Typical upper limits of pectin molecular weights are preferably of the order of 1000kDa, more preferably 800kDa. Thus, the pectin for use in the composition of the invention preferably has a molecular weight of between 50 kDa and 1000kDa.

[0030] Dextrin is preferably prepared by partial hydrolysis of starches from corn, potato, arow root, tapioca starch or wheat. The hydrolysis may be by thermal or enzymatic means. Dextrin is a combination of D-glucose units linked through a(1 - 4) or a(1 - 6) glycosidic bonds. Dextrin generally has the chemical formula (CeHioOs A preferred dextrin is one having CAS No. 9004- 53-9. It generally has a pH in the range of 4 to 5 when a 20% solution is measured at 25 °C. It is usually sold as a pale yellow powder which is odourless. The power usually has a particle size in the range of 100 to 200 .m. It is soluble in water at 20 °C. The viscosity is low since a 50% solution in water at 20 °C is measured to have a value in the range of about 50 to 200 mPa.s. A preferred supplier of dextrin is Roquette Freres, France who sell it under the brand name NutrioseRFB 06. Resistant dextrin is also known by some as maltodextrin. It is usually prepared by highly controlled partial hydrolysis of corn, potatoes, barley or wheat. It usually contains 3 to 20 D- glucose units that are linked by a(1 -4) glycosidic bond. It usually has the chemical formula C6nH(ion+2)0(5n+i). A preferred resistant dextrin has the CAS No. 9050-36-6. It is usually sold as an off-white powder which is odourless. It is soluble in water. A preferred supplier of resistant dextrin is ADM Bio Science & Technology (Tianjin) Co. Ltd., Tianjin, China who sell it under the brand name FbersolR2.

[0031] The preferred polysaccharide for use in the composition is pectin. Another preferred aspect comprises inclusion of pectin and resistant dextrin. Yet another preferred aspect comprises inclusion of pectin and dextrin. The composition preferably comprises the polysaccharide to be included at a concentration of 0.01 to 5%, preferably 0.05 to 4% by weight of the composition.

[0032] The composition of the invention comprises a hydrotrope. Suitable hydrotropes for inclusion in the composition of the invention are one or more of an alkali metal cumene sulphonate, alkali metal xylene sulphonate, polyethylene glycol (PEG) and mono propylene glycol (MPG). The preferred hydrotrope for use in the composition of the invention is alkali metal cumene sulphonate preferably sodium cumene sulphone (SCS). The preferred alkali metal xylene sulphonate is sodium xylene sulphonate (SXS). The most preferred hydrotrope for use in the present invention is SCS. It is observed that the hydrotrope SCS is more uniformly mixed in solid laundry detergent compositions e.g. a powder composition as compared to other hydrotropes. This uniformity ensures more consistent performance of the product in delivering malodour benefit. The composition preferably comprises 0.1 to 5 wt%, more preferably 0.2 to 4 wt% hydrotrope. Without wishing to be bound by theory the inventors believe that the inclusion of the hydrotrope in addition to its known property of enhancing solubility of the surfactants, increases the bioavailability of the polysaccharide thereby helping in increasing their efficacy in countering the formation of the malodour molecules from the malodour causing bacteria.

[0033] Laundry detergent composition

[0034] The composition may be delivered as a laundry detergent composition which comprisesl to 80% surfactant. The laundry detergent composition may be delivered in the form of a solid. A preferred aspect relates to a laundry detergent composition which comprises 5 to 60% anionic surfactant. The solid laundry compositions herein can take a variety of physical solid forms including forms such as powder, granule, ribbon, noodle, paste, tablet, flake, pastille and bar, and preferably the composition is in the form of powder, granule or a bar. The composition according to the present invention may be made via a variety of conventional methods known in the art including drymixing, compaction such as agglomerating, extrusion, tabletting, or spray-drying of the various compounds comprised in the detergent component, or combinations of these techniques. The powder or granule compositions preferably have a density of more than 350 grams / litre, more preferably more than 450 grams / litre or even more than 570 grams / litre.

[0035] Typical solid laundry detergent compositions comprise one or more of surfactants chosen from anionic, nonionic, zwitterionic, cationic, amphoteric types, preferably it is of the anionic type. These compositions in solid form typically comprise from 2 to 30% by weight surfactants. They may also comprise other adjuvents to provide benefits to the fabric being washed e.g soil release polymers and antiredeposition polymers which together may be included in 0 to 5% by weight of the composition. Builders are generally included especially to counteract the ill effects of hardness of water being used to wash the fabric and these account for up to 50% typically 10 to 30% by weight of the composition. Other fabric benefit agents like shading dyes and optical brightener may be included in up to 1% by weight of the composition. Bleaches may sometimes be included and when it is included it accounts for up to 10% by weight of the composition and fillers generally account for up to 40% by weight of the composition.

[0036] The solid laundry detergent composition according to the present invention preferably has a pH from 7.0 to 10.5, preferably 7.0 to 10.2, still preferably from 8.5 to 10.2, when measured at 1 wt.% dilution in de-ionised water at 25°C. The composition may preferably include a buffer.

[0037] The surfactant is generally anionic in nature. Preferred anionic surfactants are of the organic sulfates and sulfonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term “alkyl” being used to include the alkyl portion of higher acyl radicals. Examples of such materials include alkyl sulfates, alkyl ether sulfates, alkaryl sulfonates, alpha-olefin sulfonates and mixtures thereof. The alkyl radicals preferably contain from 10 to 18 carbon atoms and may be unsaturated. The alkyl ether sulfates may contain from one to ten ethylene oxide or propylene oxide units per molecule, and preferably contain one to three ethylene oxide units per molecule. The counterion for anionic surfactants is generally an alkali metal such as sodium or potassium; or an ammoniacal counterion such as monoethanolamine, (MEA) diethanolamine (DEA) or triethanolamine (TEA). Mixtures of such counterions may also be employed. Sodium and potassium are preferred.

[0038] Most preferred surfactants are of the alkylbenzene sulfonates type, particularly linear alkylbenzene sulfonates (LAS) with an alkyl chain length of from 10 to 18 carbon atoms. Some alkyl sulfate surfactant (PAS) may be used, such as non-ethoxylated primary and secondary alkyl sulphates with an alkyl chain length of from 10 to 18.

[0039] Preferably, the composition comprises from 1 to 20%, more preferably 5 to 20 wt% non-ionic surfactant based on the total weight of composition. A preferred class of nonionic surfactant for use in the invention includes aliphatic Cs to C , more preferably C12 to C15 primary linear alcohol ethoxylates with an average of from 3 to 20, more preferably from 5 to 10 moles of ethylene oxide per mole of alcohol. A preferred non-ionic surfactant are the C16 / 18 Alcohol ethoxylates.

[0040] Laundry detergent compositions also generally comprise agents like soil release polymers, hydrotropes, co-surfactants, builders, polymeric thickeners, and shading dyes in addition to the above described ingredients. Soil release polymers (SRP) help to improve the detachment of soils from fabric by modifying the fabric surface during washing. The SRP structure may also include capping groups to control molecular weight or to alter polymer properties such as surface activity. Preferred SRPs for use in the invention include copolyesters formed by condensation of terephthalic acid ester and diol, preferably 1 ,2 propanediol, and further comprising an end cap formed from repeat units of alkylene oxide capped with an alkyl group. The SRP, when included, may range from 0.1 to 10%, desirably from 0.3 to 7%, more preferably from 0.5 to 5% by weight of the composition.

[0041] The laundry detergent composition of the invention may contain one or more cosurfactants (such as amphoteric (zwitterionic) and / or cationic surfactants) in addition to the non-soap anionic and / or nonionic detersive surfactants described above. Such cosurfactant, when included, may be present in an amount ranging from 0.1 to 5% by weight of the composition.

[0042] The laundry detergent composition may also optionally contain relatively low levels of organic detergent builder or sequestrant material. Examples include the alkali metal citrates, succinates, malonates, carboxymethyl succinates, carboxylates, polycarboxylates aminocarboxylates and polyacetyl carboxylates. If utilized, the organic builder materials may comprise from about 0.5 percent to 20 wt percent, preferably from 1 wt percent to 10 wt percent, of the composition. Preferably, the composition may be used as is, i.e. neat, or it may be diluted before use. The extent of dilution is generally dependent on the type of product and the market choice. In some markets a more concentrated product is desired while in others a more dilute product is preferred. The solid laundry composition of the present invention may typically be diluted with water in a weight ratio in the range of 1 : 1 to 1 :500 preferably 1 : 1 to 1 :300 more preferably 1 : 1 to 1 : 100, most preferably 1 :1 to 1 :50.

[0043] The invention also relates to a method of reducing odour on fabric for up to five days comprising the step of contacting the fabric pre-wet with water with a composition of the first aspect; followed optionally by the steps of rinsing with water; and then drying. When the composition is formulated as a laundry detergent composition, the composition may be diluted in water after which the fabric is washed either by hand or in a machine. Thereafter the washed fabric may be rinsed two or three times, squeeze dried and thereafter dried either in a drying machine or left out to dry on a clothesline.

[0044] Another aspect of the present invention relates to a method of reducing malodour from a laundry surface comprising the step of contacting the surface with a composition of the invention preferably diluted with water followed optionally with the step of rinsing the surface with water.

[0045] The invention will now be illustrated with the help of the following non-limiting examples.

[0046] Examples

[0047] Examples A-H, 1-10: Model experiments on various combinations of LAS, pectin, and SCS or SXS on malodour generation:

[0048] Experiments were conducted using the procedure as given below to determine the amount of malodour generated on fabric. The data is summarized in Table -1 below:

[0049] 1 ml of milk + 5% starch (1 :1) was added to desized kitchen cloth (5x5 cm). The cloth was inoculated with Acinetobacter baumanii & Moraxella osloensis 108cfu / ml. Different concentrations of treatment was inoculated into respective bottle. The cups were incubated at 37 °C for 48 h. Malodour was scored by a trained panel. Table - 1:

[0050] The data in Table -1 above indicates that a composition comprising a surfactant, polysaccharide and hydrotrope (Examples 1 -10) provides for vastly improved malodour benefit as compared to individual components. (Examples A-H)

[0051] Example l-L and 11: Effect of inclusion of polysaccharide and hydrotrope in a laundry powder

[0052] A laundry detergent powder was taken as shown in Table - 2 below. Various compositions as shown in Table -3 were prepared by including certain amounts of polysaccharide and / or hydrotrope therein. The compositions were tested for malodour generation using procedure as given below- Autoclaved 5*5 cm polyester swatches are taken in a sterile petri plate. 200 J of culture mix containing tryptone, mucin and BSA was inoculated dropwise covering all places on the swatch. The swatches were allowed to dry in laminar air flow dryer for 15 mins. With the help of sterile forceps, each swatch was taken and put into sterile black screw cap bottle. 7ml of hard water was added to it. Different concentrations of treatment was inoculated into respective bottles.

[0053] Bottles were air tightly closed and incubated at 37 °C for 48-72 hours. Bottles were sniffed and scored by trained panelist.

[0054] The summary of the data is summarized in Table -3 below. Table -2:

[0055] Table - 3 The data in table -3 above indicates that inclusion of both the polysaccharide and the hydrotrope (Example 11) provides for vastly improved reduction in malodour as compared to compositions outside the invention (Examples I - L).

Claims

DEPCT691. A solid washing composition for odor reduction consisting of (i) 0.01 to 5% by weight of the polysaccharide pectin; (ii) a hydrotrope of one or more of the selected ones in 0.1 to 5% by weight of sodium cumene sulfonate or sodium xylene sulfonate; and (iii) 1 to 80% by weight of surfactants consisting of 5 to 60% by weight of anionic surfactants.

2. A composition as claimed in any of the prior claims in which the pectin is derived from one or more of the selected fruits of pear, apple, guava, plum, gooseberry, orange and other suitable citrus fruits;3. A composition as claimed in any of the prior claims in which the hydrotrope is sodium cumene sulfonate;4. An odor reduction method for washing surfaces consisting of a surface contact procedure with any suitable prior claim composition diluted with water followed, alternatively, a surface rinsing procedure with water;