DETERGENT COMPOSITIONS

Abstract: A particulate detergent composition of high bulk density has a surfactant system comprising an ethoxylated C8-C15 aliphatic alcohol nonionic surfactant of low ethoxylation (2-6) and a high degree of chain branching (at least 40 wt% based on the alcohol) and is substantially free of low-ethoxylated nonionic surfactant having a lesser degree of chain branching. The use of highly branched nonionic surfactant improves delivery of the composition to the wash in an automatic washing machine, and also gives detergency benefits.

Description: DETERGENT COMPOSITIONS TECHNICAL FIELD The present invention relates to particulate detergent compositions containing nonionic surfactants. The invention is particularly concerned with particulate detergent compositions having high bulk density. BACKGROUND AND PRIOR ART Nonionic surfactants have beneficial cleaning characteristics when included in detergent formula ions, as they are particularly effective in removing hydrophobic soils such as hydrocarbon oils, complex fats and other long-chain unsaturated and saturated glycerides. However when particulate detergent compositions containing nonionic surfactants come in contact with aqueous solutions the nonionic surfactants tend to form viscous phases which impede delivery from the dispenser of an automatic washing machine or from a delivery device, and give poor dissolution and dispersion in the wash liquor. Nonionic surfactants having a low degree of ethoxylation, employed because of their oily soil detergency, are especially problematic in this respect. In high bulk density powders the problem is exacerbated because the capillary diameter of the powder bed is smaller than in lower bulk density powders and water penetration is therefore slower. Delivery problems have also proved especially acute with powders containing water insoluble builders such as alkali metal aluminosilicates. TI TE SHEET It has now been discovered that the difficulty of producing a detergent powder containing ethoxylated alcohol nonionic surfactants and having good delivery and dissolution characteristics, without the need for any processing modifications, can be overcome by the use of highly-branched low-ethoxylate nonionic surfactants, and the exclusion of less branched materials of low degrees of ethoxylation. At the same time another benefit, of better detergency at low wash temperatures, is achieved. Spray-dried phosphate-built detergent powders of conventional bulk density containing highly branched nonionic surfactants are disclosed in GB 1 560 076 (Procter & Gamble) and GB 2 020 688B (Unilever) . High bulk density detergent powders containing nonionic surfactants are described in the art, and lists of suitable nonionic surfactants for possible inclusion in such powders may include some highly branched materials, as for example in EP 513 824A (Kao) , EP 342 043A (Procter & Gamble) and EP 364 881A (Henkel) . However, no preference for branched nonionic surfactants, or specific disclosure of their use, in high bulk density powder in the prior art is known. DEFINITION OF THE INVENTION The present invention accordingly provides a particulate detergent composition having a bulk density of at least 600 g/1 and comprising a surfactant system comprising a nonionic surfactant, at least one detergency builder and optionally other detergent ingredients, wherein the nonionic surfactant comprises a branched-chain nonionic surfactant which is an ethoxylated C 8 -C..-- aliphatic alcohol having a degree of chain branching (defined herein as the weight% of the alcohol constituted by branched material) of at least 40 wt%, and having an average degree of ethoxylation of from 2 to 6, and the surfactant system is substantially free of ethoxylated alcohol nonionic surfactants having a degree of chain branching of less than 40 wt% and a degree of ethoxylation of from 2 to 6. The invention further provides the use of a branched-chain nonionic surfactant which is an ethoxylated C--C._ aliphatic alcohol having a degree of chain branching of at least 40 wt% (based on the alcohol) and having an average degree of ethoxylation of from 2 to 6, to improve the solubility and/or rate of dissolution of a particulate detergent composition having a bulk density of at least 600 g/1. DETAILED DESCRIPTION OF THE INVENTION The surfactant system The detergent compositions of the invention are characterised by a surfactant system containing as an essential ingredient a branched-chain nonionic surfactant having a low degree of ethoxylation. As explained in more detail below, it is within the scope of the invention for further ethoxylated nonionic surfactants, outside the specifically excluded class defined above, additionally to be present. It is also within the scope of the invention for additional surfactants other than ethoxylated nonionic surfactants to be present. The total amount of detergent-active material (surfactant) in the compositions of the invention is suitably from 5 to 50 wt%. Of particular interest are high-performance compositions containing relatively high levels of surfactant, preferably from 10 to 50 wt% and more preferably from 15 to 50 wt%. The branched-chain ethoxylated nonionic surfactant The branched-chain nonionic surfactant has a degree of branching of at least 40 wt%, preferably at least 50 wt%. The degree of branching is defined here as the weight percentage of branched material (material containing any branching in the molecule) in the parent alcohol of the ethoxylate. This may be determined, for example, by NMR or by gas chromatographic mass spectrometry. For commercial materials, the information is normally available from the manufacturer. - 5 - A degree of branching of up to 100 wt% is in principle acceptable, provided that no quaternary carbon atoms are present, but for environmental reasons a degree of branching not exceeding 70 wt% is generally preferred. A preferred range for the degree of branching is from 45 to 70 wt%. Preferably, from 20 to 50% of the carbon atoms (of the alcohol) are located on side chains. Side chains are defined as all chains other than the main chain, which is defined as the longest chain identifiable in the molecule. The degree of ethoxylation of the branched-chain nonionic surfactant is from 2 to 6, preferably from 2.5 to 4. It may be advantageous for the branched-chain nonionic surfactant to have an alkyl chain length of less than C., 2 , preferably from C to C- 1 5 , as described and claimed in our copending application of even date, claiming priority from British Patent Application No. 92 24014.2 filed on 16 November 1992. However, the benefits of the present invention are also observed with longer-chain materials. It is preferred for the level of free alcohol in the nonionic surfactant to be less than 5 wt%, more preferably less than 1 wt%. Branched-chain nonionic surfactants suitable for use in the present invention include the commercially available materials listed in Table 1. (* denotes Trade Mark) . Mixtures of these materials may also be used in order to achieve intermediate degrees of ethoxylation. TABLE 1 Name Manufr. Chain EO(av) Branching length (average) (nominal) Lialet* 125-3 Enichem C,_ . _ 60% (C χ _ 4 Lialet* 125-4 Enichem C 1.2_—l.o_ 60% (C^ Lialet* 125-5 Enichem C 1.2,,—l.o_ 60% (C 1 _ 4 Lialet* 125-6 Enichem C.l__s—lo 60% (C 1-4 Lialet* 125 4-6 Enichem C 1. _-l,o_ 4-6 60% (C 1-4 Lialet* 111-3 Enichem C 11 4 % ( Cl _ 4 Lialet* 111-4 Enichem C 11 47% (C 1-4 Lialet* 111-5 Enichem C 11 47% (C χ _ 4 Lialet* 111-6 Enichem C 11 47% (C χ _ 4 Lialet* 111 4-6 Enichem C 11 4-6 47% (C 1-4 Lialet* 91 4-6 Enichem C g ,., 4-6 47% (C 1-4 Synperonic* 91-4-6 ICI g_ιι 4 ~6 60% (C 1 ) Genapol* GX-030 Hoechst C.,- 90% Genapol* OX-030 Hoechst C 60% 12-15 Ne ol* G23-3 Masso 12-13 60% Ecarol The chain distributions of some highly branched nonionic surfactants (weight percent based on the parent alcohol) preferably used in the compositions of the invention are given below. Lialet 125 series ex Enichem Total branched C._ - c : 60.00. T Lialet 111 series ex Enichem '11 (96.10%) n-C . (main chain) 49.2 C. 2-methyl 17.3 C g 2-ethyl 9.3 C 8 2-propyl 9.7 C_ 2-butyl and C 2-pentyl 10.6 Total branched material: 46.90% Examples of low-ethoxylated nonionic surfactants outside the definition above include those listed in Table 2. TABLE 2 Lorodac* LS 3L DAC C 1 η 2-1 c 6 none Inbentin* 3 olb C 12 . 14 none Dobanol* 25-3 Shell c, 1_„£—l_o_ 25% (C χ ) Dobanol* 23-3 Shell c i2 - i3 25% (C χ ) Dobanol* 91-5 Shell 9 - l 25% (C 1 ) Synperonic* A3 ICI C 12-15 48% Synperonic* A3X ICI c i2-15 42% Chain length distributions of some of these materials are given below. Dobanol 25 series ex Shell 16.3 1.9 0.8 0.9 23.4 C 12 2-methyl 3.3 C ± 1 2-ethyl 1.3 0.8 1.2 1.2 22.8 2.6 1.1 0.7 0.9 1.3 14.0 1.8 0.9 0.5 0.6 1.3 Total branched C 1 η 2—l.,b c material: 23.10% Dobanol 91 series ex Shell 0.7 17.5 1.0 0.3 0.2 40.7 2.9 1.0 1.2 25.5 C 10 2-methyl 2.4 C g 2-ethyl 1.0 Other branched 4.4 C 12 (1.6%) n-C 12 0 branched 1.6 Total branched C 8 _ 12 material: 16.00% Synperonic series ex ICI C χ3 (67.2%): n " C 13 44.0 C- 2 2-methyl 11.9 C 1L 2-ethyl 3.8 C-. 2-propyl 3.1 C g 2-butyl and C 2-pentyl 4.4 - 11 - C 14 2-methyl 2.4 C χ3 2-ethyl 1.0 C. 2 2-propyl 0.8 C.,., 2-butyl, C 2-pentyl, C Q 2-hexyl 2.4 y Total branched material: 29.80% More highly ethoxylated nonionic surfactants As already indicated, low-ethoxylated (2-6EO) nonionic surfactants which are less highly branched are excluded from the compositions of the invention. Nonionic surfactants having a higher degree of ethoxylation may, however, be additionally present. This is advantageous from the point of view of detergency. These may be either highly branched (at least 40 wt%) or less highly branched (less than 40 wt%) , the use of either being within the scope of the invention. A preferred nonionic surfactant system in compositions of the invention therefore comprises: (a) a branched-chain nonionic surfactant which is an ethoxylated C_-C 15 aliphatic alcohol having a degree of chain branching of at least 40 wt% and having an average degree of ethoxylation of from 2 to 6, and (b) a nonionic surfactant which is an ethoxylated Cg-C, 5 aliphatic alcohol having an average degree of ethoxylation of from 6.5 to 10, preferably from 6.5 to 8. Examples of nonionic surfactants of higher ethoxylation and higher branching within the definition (b) which may be used in the compositions of the invention include the higher-ethoxylated analogues of the highly branched materials listed in Table 1 above, for example, Lialet 125-7. Surprisingly, however, better powder dissolution may be observed when the more highly ethoxylated nonionic surfactant is less highly branched. An advantageous nonionic surfactant system in compositions of the invention therefore comprises: (a) a branched-chain nonionic surfactant which is an ethoxylated C -C 15 aliphatic alcohol having a degree of chain branching of at least 40 wt% and having an average degree of ethoxylation of from 2 to 6, and (b) a nonionic surfactant which is an ethoxylated C 8 -C 15 aliphatic alcohol having a degree of chain branching of less than 40 wt% and having an average degree of ethoxylation of from 6.5 to 10, preferably from 6.5 to 8. Examples of nonionic surfactants within the definition (b) include the higher-ethoxylated analogues of the less branched materials listed in Table 2 above, for example, Synperonic A7, Lorodac LS 7L, Dobanol 23-7, Dobanol 25-7. Nonionic detergent-active compounds are suitably present in the compositions of the invention in a total amount of from 2 to 50 wt%, preferably from 5 to 30 wt%. Other detergent-active compounds As previously indicated, provided that nonionic surfactants of the class specifically excluded above are absent, other detergent-active materials may be present in the compositions of the invention. Detergent-active material present other than the nonionic surfactants may be other anionic (soap or non-soap) , cationic, zwitterionic, amphoteric, or any combination of these. Anionic detergent-active compounds may be present in an amount of from 0 to 40 wt%, preferably from 0 to 20 wt%. It is preferred if the ratio of nonionic surfactant to anionic surfactant is within the range of 2:8 to 9:1. Synthetic anionic surfactants are well known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly sodium linear alkylbenzene sulphonates having an alkyl chain length of C 8 -C 15 ; primary and secondary alkyl sulphates, particularly sodium C -C 15 primary alcohol sulphates, olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinate; and fatty acid ester sulphonates. It may also be desirable to include one or more soaps of fatty acids. These are preferably sodium soaps derived from naturally occurring fatty acids, for example, the fatty acids from coconut oil, beef tallow, sunflower or hardened rapeseed oil. Preferred surfactant systems Especially preferred compositions in accordance with the invention have surfactant systems consisting essentially of branched-chain ethoxylated nonionic surfactant as defined above in combination with linear alkylbenzene sulphonate (LAS) or primary alcohol sulphate (PAS) or both. Surfactant systems of especial interest consist essentially of (i) from 40 to 100 wt% of the ethoxylated nonionic surfactant, and (ii) from 0 to 60 wt% of linear alkylbenzene sulphonate and/or primary C -C alcohol sulphate. HEET Detergency builders The detergent powders of the invention contain one or more detergency builders, suitably in an amount of from 5 to 80 wt%, preferably from 20 to 60 wt%. The invention is especially applicable to compositions containing alkali metal aluminosilicates as builders. Alkali metal (preferably sodium) aluminosilicates may generally be incorporated in amounts of from 5 to 60% by weight (anhydrous basis) of the composition, preferably from 25 to 55 wt%, and suitably, in a heavy duty detergent composition, from 25 to 48 wt%. The alkali metal alu inosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na 2 0. A1 2 0 3 . 0.8-6 Siθ 2 These materials contain some bound water and are reguired to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiO_ units (in the formula above) . Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble) . The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof. The zeolite may be the commercially available zeolite 4A now widely used in laundry detergent powders. Alternatively, the zeolite builder incorporated in the compositions of the invention is maximum aluminium zeolite p (zeolite MAP) as described and claimed in EP 384 070A (Unilever) . Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, and more preferably within the range of from 0.90 to 1.20. Especially preferred is zeolite MAP having a silicon to aluminium ratio not exceeding 1.07. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material. Other builders may also be included in the detergent compositions of the invention if necessary or desired. Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB 1 437 950 (Unilever) . Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di- and trisuccinates, carboxymethyloxysuccinates, carboxymethyloxymalonates , dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. This list is not intended to be exhaustive. Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form. Especially preferred supplementary builders are polycarboxylate polymers, more especially polyacrylates and acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, especially from 1 to 10 wt%; and monomeric BSTITUTE SHEET polycarboxylates, more especially citric acid and its salts, suitably used in amounts of from 3 to 35 wt%, more preferably from 5 to 30 wt%. Preferred compositions of the invention preferably do not contain more than 5 wt% of inorganic phosphate builders, and are desirably substantially free of phosphate builders. The compositions in accordance with the invention may contain alkali metal, preferably sodium, carbonate, to increase detergency and to ease processing. Sodium carbonate may generally be present in amounts ranging from 1 to 60 wt%, preferably from 2 to 40 wt%, and most suitably from 2 to 13 wt%. However, compositions free of alkali metal carbonate are also within the scope of the invention. Other ingredients Fully formulated laundry detergent compositions in accordance with the present invention may additionally contain any suitable ingredients normally encountered, for example, inorganic salts such as sodium silicate or sodium sulphate; organic salts such as sodium citrate; antiredeposition aids such as cellulose derivatives and acrylate or acrylate/maleate polymers; fluorescers; bleaches, bleach precursors and bleach stabilisers; proteolytic and lipolytic enzymes; dyes; coloured speckles; perfumes; foam controllers; fabric softening compounds. Processing and powder properties The particulate detergent compositions of the invention may in principle be prepared by any of the available tower (spray-drying) , non-tower (granulation) or combination processes. Of especial interest are compositions of high bulk density - at least 600 g/1, preferably at least 700 g/1 and more preferably at least 800 g/1 - which may be prepared by granulation and/or densification in a high-speed mixer/granulator. The high-speed mixer/granulator, also known as a high-speed mixer/densifier, may be a batch machine such as the Fukae (Trade Mark) FS, or a continuous machine such as the LOdige (Trade Mark) ecycler CB30. Suitable processes are described, for example, in EP 340 013A, EP 367 339A, EP 390 251A, EP 420 417A and EP 506 184A (Unilever) . One suitable method comprises spray-drying a slurry of compatible heat-insensitive ingredients, including zeolite and any other builders, and at least part of the detergent-active compounds: densifying the resulting base powder in a batch or continuous high-speed mixer/granulator; and then spraying on or postdosing those ingredients, for example, bleach, enzymes, unsuitable for processing via the slurry. In another method, the spray-drying step can be omitted altogether, a high bulk density base powder being prepared directly from its constituent raw materials, by mixing and granulating in a high-speed mixer/granulator, and then postdosing bleach and other ingredients as in the spray-drying/post-tower densification route. Generally the inorganic builders and other inorganic materials (for example, zeolite, sodium carbonate) are granulated with the surfactants, which act as binders and granulating or agglomerating agents. Where an anionic surfactant such as PAS is present, a mobile surfactant blend as described in EP 265 203A (Unilever) or EP 507 402A (Unilever) may suitably be used. Any optional ingredients as previously mentioned may be incorporated at any suitable stage in the process. In accordance with normal detergent powder SUBSTITUTE SHEET manufacturing practice, bleach ingredients (bleaches, bleach precursor, bleach stabilisers) , proteolytic and lipolytic enzymes, coloured speckles, perfumes and foam control granules are most suitably admixed (postdosed) to the dense granular product after it has left the high-speed mixer/granulator. The low-ethoxylated highly branched nonionic surfactants with which the present invention is concerned will not normally be included in the base powder but will be admixed with, for example, sprayed onto, the finished base powder. Nonionic surfactants of higher ethoxylation may be included in the base powder, post-added, or both. Preferably at least a part of any higher-ethoxylated nonionic surfactant is included in the base powder, while either low-ethoxylated surfactant alone or a mixture of higher- and low-ethoxylated nonionic surfactant is post-added. EXAMPLES The following non-limiting Examples illustrate the invention. Examples identified by numbers are in accordance with the invention, those identified by letters are comparative. Parts and percentages are by weight unless otherwise stated. Examples 1 and 2. Comparative Examples A and B Particulate detergent compositions were prepared by spray-drying aqueous slurries to form base powders (including nonionic surfactants as specified) , densifying the base powder in a continuous LfJdige high-speed mixer/granulator, spraying on further nonionic surfactants as specified, and then admixing the remaining ingredients. The general formulation in weight percent is shown in Table 3. TABLE 3 Base powder Linear alkylbenzene sulphonate 8.60 *Nonionic surfactant (i) 1.92 Zeolite 4A 1 23.61 Acrylic/maleic copolymer 2 3.51 Sodium carbonate 7.49 Minor ingredients 3 1.35 Moisture 9.02 55.50 Sprayed on **Nonionic surfactant (ii) 4.68 Admixed Zeolite 4A Sodium carbonate Granular sodium silicate Sodium perborate monohydrate EDTMP 5 Antifoam granules Enzyme granules Perfume ♦specified below **specified below: when mixtures of two nonionic surfactants was used, they were in equal proportions (2.34 wt% each). Wessalith (Trade Mark) P powder ex Degussa: percentage is for anhydrous material, the water of hydration being included in the figure for total moisture. Sokalan (Trade Mark) CP5 ex BASF. 3 Fluorescer, sodium carboxymethylcellulose, salts, etc. 4 Tetraacetylethylenediamme, as 83 wt% granules. 5Ethylenediammetetramethylenephosphonic acid, calcium salt: Dequest (Trade Mark) 2047 ex Monsanto (34 wt% active) . Antifoam granules in accordance with EP 266 863B (Unilever) . The powders had bulk densities above 700 g/litre. The nonionic surfactants used were as shown in Table 4, Details of all these materials are given earlier in this specification. TABLE 4 Example Surfactant (i) Surfactant (ii) (base powder) (sprayed on) Synperonic A7 Synperonic A3 Synperonic A7 B Synperonic A7 Synperonic A3 Synperonic A7 Dobanol 25-3 D Lialet 125-7 Synperonic A3 Synperonic A7 Synperonic A7 Lialet 125-3 Synperonic A7 Genapol GX-030 Synperonic A7 Lialet 111-3 Synperonic A7 Lialet 111-3 Lialet 111-7 Lialet 125-7 Lialet 125-3 Lialet 125-7 Lialet 125-3 Lialet 125-7 The powders were compared using two different tests . SUBSTITUTE SHEET Test 1 Delivery characteristics of the powders were compared using a model system which emulates the delivery of a powder in an automatic washing machine from a flexible delivery device of the type supplied with Lever's Persil (Trade Mark) Micro System powder in the UK: a spherical container of flexible plastics material having a diameter of approximately 4 cm and a top opening of diameter approximately 3 cm. In this test the delivery device was attached in an upright position (opening uppermost) to an agitator arm positioned above water. By means of this apparatus the device could be moved vertically up and down through a distance of 30 cm, the lowest 5 cm of this travel being under water. Each up or down journey had a duration of 2 seconds, the device being allowed to rest 5 cm under water for 4 seconds at the lowest position, and at the highest position being rotated through 100° and allowed to rest in the resulting tilted orientation for 2 seconds before redescending. 5 litres of water at a temperature of 20°C were used. A preweighed powder sample was introduced into the device in its highest position, and the apparatus then allowed to operate for six cycles and stopped when the device was again in its highest position. Surface water was carefully poured off, and any powder residues transferred to a preweighed container. The container was then dried at 100°C for 24 hours, and the weight of dried residue as a percentage of the initial powder weight calculated. The results are shown in Table 5. TABLE 5 Example Surfactant (i) Surfactant fii) Residue (base powder) (sprayed on) (wt%) Synperonic A7 Synperonic A3 52 Synperonic A7 B Synperonic A7 Synperonic A3 75 Synperonic A7 Lialet 125-3 Test 2 The powders were also compared by means of a washing machine test. The machine used was a Siemens Siwa at (Trade Mark) Plus 3700 front-loading automatic washer and the test methodology was as follows. A 100 g dose of powder was placed in a flexible delivery device as described previously. The delivery device was placed inside a black cotton pillowcase having dimensions of 30 cm by 60 cm, taking care to keep it upright, and the pillowcase was then closed by means of a zip fastener. The pillowcase containing the (upright) delivery device was then placed on top of a 3.5 kg dry cotton washload in the drum of the washing machine. SUBSTITUTE SHEET The machine was operated on the "heavy duty cycle" at a wash temperature of 60°C, using water of 15° French hardness and an inlet temperature of 20°C. At the end of the wash cycle the pillowcase was removed, opened and turned inside out, and the level of powder residues on its inside surfaces determined by visual assessment using a scoring system of 1 to 3: a score of 3 corresponds to a residue of approximately 75 wt% of the powder, while 1 indicates no residue. A panel of five assessors was used to judge each pillowcase and allot a score. With each powder the wash process was carried out ten times and the scores were averaged over the ten repeats. The results were as shown in Table 6. TABLE 6 Example Surfactant Ci) Surfactant fii) Score (base powder) (sprayed on) Synperonic A7 Synperonic A3 2.6 Synperonic A7 B Synperonic A7 Synperonic A3 3.0 Synperonic A7 Dobanol 25-3 2.9 Lialet 125-7 Synperonic A3 2.5 Synperonic A7 Synperonic A7 Lialet 125-3 1.4 Synperonic A7 Genapol GX-030 1.5 Synperonic A7 Lialet 111-3 1.3 Synperonic A7 Lialet 111-3 2.2 Lialet 111-7 Lialet 125-7 Lialet 125-3 1.6 Lialet 125-7 Lialet 125-3 2.3 Lialet 125-7 HEET Detergency A washing machine test was also carried out to compare the detergencies of the compositions of Examples A, B, C (comparative) and 1 and 2 (in accordance with the invention) . The machine was again a Siemens Siwamat. 3 kg loads containing WFK-IOC test cloth monitors (cotton soiled with a mixed fatty and particulate soil: wool fat and kaolin) were washed at 20°C using the half load main wash cycle. The powder samples (80 g dose) were introduced via the machine's dispenser. Detergency results (reflectance increases at 460 nm of the test cloth monitors) were as follows: Example Reflectance increase 7.1 B 5.6 8.0 15.3 13.9 These results demonstrate the additional benefit associated with the invention, of improved detergency. - 27 - Example 7, Comparative Example E In this Example the dispersability of high bulk density base powders containing different nonionic surfactants was compared in a test designed to detect the formation of gel surfactant phases as the powder is wetted. The powders were prepared as follows. In each case, the base powder was prepared by granulation with in-situ neutralisation in a high-speed mixer/granulator, as described in EP 420 417A and EP 506 184A (Unilever), and the remaining ingredients were then admixed. The finished powders had bulk densities in the 800-900 g/1 range. The formulations (in parts by weight) were as follows: CocoPAS 6.51 6.51 Nonionic surfactant: Lorodac 7 6.48 Lorodac 3 8.19 Lialet 111-7 - 6.48 Lialet 111-3 - 8.19 Soap 2.26 2.26 Zeolite MAP (hydr) 41.74 41.74 Carbonate 1.11 1.11 SCMC 1.02 1.02 - 28 - The nonionic surfactants were as follows: The dispersion test was carried out as follows. An 0.3 g sample of powder was placed in a small spoon and wetted by holding the spoon horizontally in water at 10°C for 1 minute. The spoon was then removed and surplus water poured off. The spoon with the damp powder was then placed horizontally in a 500 ml beaker of water at 10°C and a stirrer (a magnetic flea set to give a 25 mm vortex) was activated. Turbidity (as indicator of the dispersion of the zeolite) was measured as a function of time. The 90% dispersion times were as follows: Comparative Example E 4.50 minutes Example 7 1.66 minutes Examples 8 and 9 , Comparative Examples F and G In these Examples, the oily soil detergencies (percentage removal of radio-labelled triolein soil from polyester) of surfactant systems containing cocoPAS (30 parts) and different nonionic surfactants (70 parts) having similar degrees of ethoxylation were compared in the tergotometer using a 5 g/1 product concentration, 24° (French) hard water, and a wash temperature of 20°C. Compositions were prepared to the following general formulation, nonionic surfactants and detergencies being shown in the table below: arts Ex. Nonionic Chain Branching EO Detergency surfactant length Dobanol 91-5 9-11 16% 5.0 12.4 Lialet 111-4 0 27.1 11 47% 4. 9 Lialet 111-5 C^ 47? 5.0 27.1 Coco 7E0/, coco 3EO .3 '12-14 none 4.5-5 23 (30/40) TITUTE SHEET - 30 - Examples 10 and 11. Comparative Examples H and J The procedure of Examples 8, 9, F and G was repeated using compositions in which the surfactant systems each consisted of 10 parts of cocoPAS and 90 parts of ethoxylated nonionic surfactant. Compositions were prepared to the following general formulation, nonionic surfactants and detergencies being shown in the table below: arts Ex. Nonionic Chain Branching EO Detergency surfactant length F Dobanol 91-5 C Q y—.. 16? 5.0 33.5 Lialet 111-4 11 47% (C x _ 4 ) 4.0 41.7 Lialet 111-5 11 47% (C 1-4 ) 5.0 37.8 COCO 7E0/, coco 3EO '12-14 none 4.5-5 36.1

Claims: CLAIMS 1 A particulate detergent composition having a bulk density of at least 600 g/1 and comprising a surfactant system comprising a nonionic surfactant, at least one detergency builder and optionally other detergent ingredients, wherein the nonionic surfactant comprises a branched-chain nonionic surfactant which is an ethoxylated C -C aliphatic alcohol having a degree of chain branching (defined herein as the weight% of the alcohol constituted by branched material) of at least 40 wt%, and having an average degree of ethoxylation of from 2 to 6, and the surfactant system is substantially free of ethoxylated alcohol nonionic surfactants having a degree of chain branching of less than 40 wt% and a degree of ethoxylation of from 2 to 6. 2 A detergent composition as claimed in claim 1, wherein the branched-chain nonionic surfactant has a degree of chain branching of from 45 to 70 wt%. 3 A detergent composition as claimed in claim 1, wherein the branched-chain nonionic surfactant has a degree of chain branching of at least 50 wt%. 4 A detergent composition as claimed in claim 1, wherein the branched-chain nonionic surfactant has an average degree of ethoxylation of from 2.5 to 4. SUBSTITUTESHEET 5 A detergent composition as claimed in any preceding claim, wherein the surfactant system also comprises a further nonionic surfactant which is a condensation product of ethylene oxide with a C 8 -C 15 aliphatic alcohol having an average degree of ethoxylation within the range of from 6.5 to 10. 6 A detergent composition as claimed in claim 5, wherein the further nonionic surfactant has a degree of ethoxylation within the range of from 6.5 to 8. 7 A detergent composition as claimed in claim 5 or claim 6, wherein the further nonionic surfactant has a degree of chain branching of less than 40 wt%. 8 A detergent composition as claimed in any preceding claim, wherein the surfactant system further comprises anionic surfactant. 9 A detergent composition as claimed in claim 8, wherein the surfactant system consists essentially of linear alkylbenzene sulphonate and/or primary alcohol sulphate, and ethoxylated nonionic surfactant. 10 A detergent composition as claimed in claim 9, wherein the surfactant system consists essentially of (i) from 40 to 100 wt% of ethoxylated nonionic surfactant, and (ii) from 0 to 60 wt% of linear alkylbenzene sulphonate or primary C 0 -C. o alcohol sulphate. 11 A detergent composition as claimed in any preceding claim, which contains from 10 to 50 wt% of the surfactant system. 12 A detergent composition as claimed in any preceding claim, which comprises as detergency builder from 20 to 60 wt% (anhydrous basis) of alkali metal aluminosilicate. 13 A detergent composition as claimed in any preceding claim, having a bulk density of at least 700 g/1. 14 Use of a branched-chain nonionic surfactant which is an ethoxylated C 8 -C ιg aliphatic alcohol having a degree of chain branching of at least 40 wt% (based on the alcohol) and having an average degree of ethoxylation of from 2 to 6, to improve the solubility and/or rate of dissolution of a particulate detergent composition having a bulk density of at least 600 g/1. SUBSTITUTE SHEET

Inventors: CARTER MALCOLM NIGEL ALAN DI, HOUGHTON MARK PHILIP, HULL MICHAEL, CARTER, MALCOLM, NIGEL, ALAN +DI, HOUGHTON, MARK, PHILIP, HULL, MICHAEL
Applicants: UNILEVER NV, UNILEVER PLC
Application year: 1993
Main classification: C11D17
IPC codes: C11D1, C11D17