COLOURED GRANULAR COMPOSITION FOR USE IN PARTICULATE DETERGENT COMPOSITIONS

Abstract: A granular composition suitable for incorporation into a particulate detergent composition comprises: (a) a coloured or fluorescent ingredient, for example, a photobleach such as zinc or aluminium phthalocyanine sulphonate; (b) a carrier material for the coloured or fluorescent ingredient which is an alpha -hydroxy organic acid, preferably citric acid; (c) a water-soluble or water-dispersible barrier material, preferably a water-soluble starch or polyvinyl alcohol; and (d) an inorganic flow modifier, for example, silica and/or china clay. Preferably, the coloured or fluorescent ingredient is dispersed onto the alpha -hydroxyacid which is mixed with part or all of the inorganic flow modifier and the whole treated with the barrier material, then granulated with any remaining inorganic flow modifier. The granular material can be incorporated into particulate detergent compositions, where it shows a reduced tendency to leave stains on washed fabrics.

Description: COLOURED GRANULAR COMPOSITION FOR USE IN PARTICULATE DETERGENT COMPOSITIONS Technical field The present invention relates to a fast-dissolving, low- staining granular composition containing a visually distinct, eg coloured or fluorescent, ingredient, for example, a photobleach. The invention more particularly relates to granules containing a coloured or fluorescent ingredient which may be incorporated into a detergent composition without encountering the problem of staining of the fabric during the wash. Background and Prior Art Coloured speckles are used in detergent formulations to give a distinct appearance to the product as well as to deliver functional benefits. In the wash process, it is undesirable that these coloured speckles settle on to the fabric surface leading to staining of the fabric. It has also been noticed that these stains do not get washed out in subsequent laundering. Further the uneven concentration of these speckles on the substrate could result in localised higher levels of the active causing fabric damage. US 4 097 418 (Procter & Gamble, 1978) discloses a granular coloured speckle having non-staining qualities comprising an agglomerate of a granular water soluble inorganic alkaline salt with an anionic surfactant which contains a dye or pigment. Mixing of the dye and the anionic surfactant prior to agglomeration prevents the pigment particles from attaching to each other and on to the fabric surface thus preventing staining of the fabric. US 4 762 636 (Ciba-Geigy, 1988) discloses a process for obtaining granules with defined physical properties that float on an aqueous treatment liquor and release the active ingredient without getting deposited on to the substrate. Summary of the invention It is thus an object of the present invention to provide a granule composition containing a coloured or fluorescent ingredient which may be incorporated into a detergent composition without encountering the problem of staining of the fabric during the wash process. It is a further object of the invention to provide a granule composition having a superior non-staining property, which may be manufactured by a process which is more economical and would involve lower capital cost as compared to the known processes . Accordingly the present invention provides a granular composition suitable for incorporation into a particulate detergent composition, the granular composition comprising (a) a coloured or fluorescent ingredient, (b) an α-hydroxy organic acid as a carrier material for the coloured or fluorescent ingredient, (c) a water-soluble or water-dispersible barrier material, and (d) an inorganic flow modifier. The water-soluble or water-dispersible barrier material serves to provide a protective layer or coating on the combination of the coloured or fluorescent ingredient and its carrier material, the α-hydroxy organic acid. Preferably at least a part of the inorganic flow modifier is also thus protected. Additional inorganic flow modifier that is not protected by the barrier material may also be present . The term coating used above does not necessarily imply complete coating. According to a preferred embodiment of the invention, therefore, the coloured or fluorescent ingredient is dispersed onto, or in the form of a coating over, the α-hydroxy organic acid, the α-hydroxy organic acid carrying the coloured or fluorescent ingredient is in admixture with the flow modifier or a portion thereof, the barrier material is in the form of a coating over the said mixture of α-hydroxy organic acid and flow modifier, being combined with (in admixture with) any remaining portion of the flow modifier. According to a further preferred aspect of the invpention the granule composition comprises: from 40 to 90% by weight, preferably from 60 to 80% by weight, of the α-hydroxy organic acid, from 0.5 to 5% by weight, preferably from 1 to 2% by weight, of the coloured or fluorescent ingredient, - from 10 to 50% by weight, preferably from 18 to 40% by weight, of the inorganic flow modifier, and from 0.5 to 5% by weight, preferably from 1 to 3% by weight, of the water soluble barrier material. The granular composition of the invention may be prepared by a process in which the coloured or fluorescent ingredient is dispersed onto the α-hydroxyacid, which is then mixed with part or all of the inorganic flow modifier and the whole treated with the barrier material, then granulated with any remaining inorganic flow modifier. According to a further aspect of the invention, therefore, there is provided a process for the preparation of a granule composition which comprises the steps of: (i) dispersing the coloured or fluorescent ingredient on the α-hydroxy acid and granulating with the inorganic flow modifier or a portion thereof; (ii) drying the material, preferably at a temperature within the range of from 15 to 50°C, more preferably from 20 to 40°C; (iii) treating the dried material with the water-soluble or water-dispersible barrier material; (iv) optionally, granulating the said treated material with any remaining flow aid modifier and drying. The α-hydroxy organic acid may be selected from citric acid, adipic acid, tartaric acid, maleic acid and others. An especially preferred acid is citric acid. Examples of coloured or fluorescent ingredients are photoactivators (also known as photobleaches) , especially phthalocyanines; coloured dyes and pigments; fluorescent whitening agents; and mixtures thereof. Especially preferred ingredients are the photobleaches, zinc and aluminium phthalocyanine sulphonates . The inorganic flow modifier can be selected from china clay, (preferably washed china clay) , silica, precipitated silica, precipitated calcium carbonate and diatomaceous/siliceous earth. China clay, silica and mixtures thereof are especially preferred. The water-soluble or water-dispersible, preferably water- soluble, barrier material may suitably be selected from water-soluble starches, polyvinyl alcohols, polyethylene glycols and latex. Preferred materials are starches and polyvinyl alcohols. As previously indicated, the granules of the present invention may be prepared by dispersing the coloured or fluorescent ingredient on the α-hydroxy organic acid, for example, in a rotary pan granulator, and subsequently or simultaneously adding a suitable flow modifier. The resultant agglomerate is dried and further coated with the water-soluble or water-dispersible barrier material, and optionally granulated with further flow modifier and dried. A further subject of the invention is a particulate detergent composition comprising organic detergent surfactants and other detergent ingredients, and comprising a granular composition as defined previously. The particulate laundry detergent composition of the invention may suitably comprise from 5 to 60 wt% of organic surfactant, from 10 to 80 wt% of detergency builder, from 0.1 to 10 wt%, preferably from 0.5 to 5 wt%, of a granular composition as defined previously, and optionally other detergent ingredients to 100 wt% . The invention will now be illustrated further by means of the following non-limiting Examples, in which parts and percentages are by weight unless otherwise stated. Examples denoted by a number are in accordance with the invention, while Examples denoted by a letter are comparative. EXAMPLE 1, COMPARATIVE EXAMPLES A TO C Preparation of granular compositions Example 1: photobleach granules using citric acid carrier and starch barrier material 8 Kg of citric acid were placed in a rotary pan granulator and 200 g of aluminium phthalocyanine sulphonate solution (10% concentration) were sprayed on to it. During spraying, half the quantity of a mixture of 0.8 kg of china clay and 500 g of silica was added. The material was dried at 40°C for about 4 hours. The material was taken back into a rotary pan granulator and 500 g of starch solution (concentration 10% by weight) was sprayed on. The balance half of the mixture of china clay and silica was added. The material was dried at 40°C for 4 hours. The formulation of the granular material was as follows Example 2 : photobleach granules using citric acid carrier and polyvinyl alcohol barrier material Photobleach granules were prepared as in Example 1 but the starch solution was replaced by polyvinyl alcohol solution (concentration 10% by weight) . The final formulation of the granular material was as follows : Comparative Example A Granules were prepared by the process of Example 1 but using soda ash instead of citric acid. Comparative Example B Granules were prepared by the process of Example 1 but using sodium tripolyphosphate instead of citric acid. Wash protocol Cotton fabric pieces of dimension 10 inch x 10 inch (25.4 cm x 25.4 cm) were placed in trays, each together with 2 kg of water and one of the following photobleach granular compositions : Example 1 Comparative Example A Comparative Example B Comparative Example C: commercially available blue speckles, Laundrosil (Trade Mark) PRT-2 ex Sud-Chemie, containing aluminium phthalocyanine sulphonate on a bentonite clay carrier. Each fabric piece was allowed to soak for 30 minutes. Later the fabric was washed in running water and dried in the sun. Four replications were maintained for each treatment. A panel of trained members analysed the fabric visually for blue stains on a scale of 0 to 5 as follows: Scores Staining level 0-1 minimal/negligible 2-3 perceptible 4-5 significant blue staining The data were analysed statistically and are shown in the following Table. The data presented in the table show that the commercially available granules stained the fabric considerably while the use of the granules according to the invention had a significantly superior effect in controlling the staining of the fabric. This is further substantiated by the fact that granules made by the same process but by replacing the citric acid with soda ash or sodium tripolyphosphate did not prevent staining of the fabric significantly. EXAMPLES 3 and 4: DETERGENT COMPOSITIONS Granular detergent compositions were prepared by dry mixing to the following formulations: Linear alkylbenzene sulphonate 30 Sodium carbonate 20 Sodium tripolyphosphate 40 Photobleach granules (see below) 2 Enzymes, perfume, fluorescer, water etc to 100 The detergent composition of Example 3 contained the photobleach granules of Example 1 (citric acid carrier, starch barrier material) . The detergent composition of Example 4 contained the photobleach granules of Example 2 (citric acid carrier, polyvinyl alcohol barrier material) . Both detergent compositions were stored in 500 g pouches from May to December under the following conditions representing summer, monsoon and winter conditions in India: No instability, as determined by visual inspection, could be detected at the end of the storage period.

Claims: CLAIMS 1 A granular composition suitable for incorporation into a particulate detergent composition, the granular composition comprising (a) a coloured or fluorescent ingredient, (b) a carrier material for the coloured or fluorescent ingredient, characterised in that the carrier material (b) is an α-hydroxy organic acid, and the granular composition further comprises (c) a water-soluble or water-dispersible barrier material, and (d) an inorganic flow modifier. 2 A granular composition as claimed in claim 1, characterised in that: the coloured or fluorescent ingredient (a) is dispersed onto, or in the form of a coating over, the α-hydroxyacid (b) , which is in admixture with the inorganic flow modifier (d) or a portion thereof, and the barrier material (c) is in the form of a coating over the mixture of coated α-hydroxyacid and inorganic flow modifier, the coated mixture being in admixture with any remaining inorganic flow modifier (d) . 3 A granular composition as claimed in any preceding claim, characterised in that it comprises: (a) from 0.5 to 5% by weight, preferably from 1 to 2% by weight, of the coloured or fluorescent ingredient, (b) from 40 to 90% by weight, preferably from 60 to 80% by weight, of the α-hydroxy organic acid, (c) from 0.5 to 5% by weight, preferably from 1 to 3% by weight, of the water-soluble or water-dispersible barrier material . (d) from 10 to 50% by weight, preferably from 18 to 40% by weight, of the inorganic flow modifier. 4 A granular composition as claimed in any preceding claim, characterised in that the coloured or fluorescent ingredient (a) is selected from photoactivators (photobleaches) , pigments, dyes, and fluorescent whitening agents . 5 A granular composition as claimed in claim 4, characterised in that the coloured or fluorescent ingredient (a) is a zinc or aluminium phthalocyanine sulphonate. 6 A granular composition as claimed in any preceding claim, characterised in that the α-hydroxyacid (b) is selected from citric acid, adipic acid, maleic acid and tartaric acid. 7 A granular composition as claimed in claim 6, characterised in that the α-hydroxyacid (b) is citric acid. 8 A granular composition as claimed in any preceding claim, characterised in that the water-soluble or water- dispersible barrier material (c) is selected from water- soluble starches, polyvinyl alcohols, polyethylene glycols, and latices . 9 A granular composition as claimed in claim 8, characterised in that the barrier material (c) is water- soluble and is a starch or a polyvinyl alcohol. 10 A granular composition as claimed in any preceding claim, characterised in that the inorganic flow modifier (c! is selected from china clay, silica, precipitated silica, precipitated calcium carbonate, and diatomaceous or siliceous earth. 11 A granular composition as claimed in claim 10, characterised in that the inorganic flow modifier (c) comprises china clay, silica or a mixture thereof. 12 A particulate laundry detergent composition which comprises from 5 to 60 wt% of organic surfactant, from 10 to 80 wt% of detergency builder, and optionally other detergent ingredients to 100 wt%, characterised in that it comprises from 0.1 to 10 wt%, preferably from 0.5 to 5 wt% , of a granular composition as claimed in any one of claims 1 to 11. 13 A process for the preparation of a granular composition as claimed in claim 1, characterised in that it comprises the steps of: (i) dispersing the coloured or fluorescent ingredient (a) onto the α-hydroxyacid (b) , and granulating with a portion or the whole of the inorganic flow modifier (d) , (ii) drying the granular material thus obtained, (iii) treating the dried material with the water-soluble or water-dispersible barrier material (c) , (iv) optionally, granulating the treated material thus obtained with any remaining inorganic flow modifier (d) and drying. 14 A process as claimed in claim 13, characterised in that the drying step (iii) is carried out at a temperature within the range of from 15 to 50°C, preferably from 20 to 40°C.

Inventors: DARU VIJAY, PEREIRA WINSTON ANTHONY, SENGUPTA RANA, DARU, VIJAY, PEREIRA, WINSTON, ANTHONY, SENGUPTA, RANA
Applicants: DARU VIJAY, LEVER HINDUSTAN LTD, PEREIRA WINSTON ANTHONY, SENGUPTA RANA, UNILEVER NV, UNILEVER PLC, DARU, VIJAY, HINDUSTAN LEVER LIMITED, PEREIRA, WINSTON, ANTHONY, SENGUPTA, RANA, UNILEVER N.V.
Application year: 1999
Main classification: C11D
IPC codes: C11D3, C11D17