LAVATORY CLEANSING

Abstract: In a process for the production of lavatory cleansing blocks by extruding a mixture of appropriate ingredients for the block, the mixture to be extruded comprises, based on the total weight of the mixture; (i) from 5 to 85 % by weight, of one or more anionic surface active agents; and (ii) from 0.5 to 40 % by weight of one or more rheological control agents.

Description: LAVATORY CLEANSING This invention is concerned with improvements in and relating to lavatory cleansing blocks. In particular, the present invention is concerned with so-called "free standing" lavatory cleansing blocks which are immersed n the water cistern of a lavatory or urinal so that cleansing ingredients contained in the block are slowly dissolved in the water of the cistern. On flushing of the lavatory or urinal, the water from the cistern, containing dissolved cleansing ingredients, is flushed into the lavatory bowl or urinal and serves to cleanse it. Generally such lavatory cleansing blocks comprise two principal components, namely: (i) a surface active or detergent component comprising one or more surface active or detergent agents, and fii) a solubility retardant or solubility control component, which serves to control the rate of dissolution of the block in the water of the cistern and which comprises one or more, more or less water-insoluble components. In addition to these two principal components, free¬ standing lavatory cleansing blocks commonly contain one or more of inert fillers, water-softening agents (which may also serve to some extent as fillers), colouring agents (especially water-soluble dyestuffs, commonly of a blue or green colour), perfumes and germicides or preservatives. When first manufactured on a commercial scale, lavatory cleansing blocks were made by a "melt" process; that is the components for the block were melted together and the melt cast into moulds to form the desired blocks. The "melt" process effectively precludes the use of high melting or difficultly meltable materials and especially precludes the use, as surfactants, of anionic surfactants; well-known and readily available surfactant materials. Lavatory cleansing blocks containing anionic surfactants may be made by a compression process, e. g. a tabletting process or, especially, an extrusion process; in which a mixture of the components of the block is compressed and extruded to form a rod or bar which is subsequently divided into pieces of the desired size. We have now found that it is possible to manufacture blocks having a satisfactory in-use life by an extrusion process, which blocks comprise an anionic surfactant together with a rheological control agent, which latter serves, inter alia, to control the in-use life of the block. Accordingly, the present invention provides a process for the production of lavatory cleansing blocks by extruding a mixture of appropriate ingredients for the blocks into rod form and subsequently cutting the rod into blocks of the desired size, in which the mixture to be extruded comprises, based on the total weight of the mixture; (i) from 5 to 85%, preferably from 10 to 70%, more preferably from 20 to 50% by weight of one or more anionic surface active agents; and (ii) from 0.5 to 40%, preferably from 3 to 15% by weight, of one or more rheological control agenets. The mixture to be compressed may also suitably contain, as discussed in more detail below, (iii) one or more solubility control agents, suitably in an amount of up to 20% by weight, preferably from 5 to 15% by weight; and (iv) one or more fillers suitably in an amount of up to 75% by weight, preferably from 15% to 55% by weight. The anionic surface active agent used in the blocks of the invention may be, for example, an alkali metal, typically sodium, paraffin sulphonate; alkali metal alkyl sulphate or alkali metal alkyl aryl sulphonate; especially an alkali metal alkyl benzene sulphonate. In particular, sodium dodecyl benzene sulphonate may be mentioned as it is a readily commercially available anionic surface active agent. Anionic surfactants, as commercially available, commonly contain minor amounts of inert water-soluble filler such as sodium sulphate. In determining the amount of surfactant present in the block of the invention we refer to the true content of actual surfactant mentioned so that any filler which may be present contributes to any filler content [component (iv)] of the block. In addition to the anionic surface active agent component, other surface active or detergent materials may be present m the block, especially nonionic surface active materials. Such materials should preferably be present in lesser amounts than the anionic surface active agent and thus may, for example, form upto 40%, preferably up to 10%, of the weight of the block. Typical nonionic surface active agents which may be employed include polyalkoxylated, usually poly- ethoxylated, fatty acids, fatty alcohols and alkyl phenols; and ethylene oxide/propylene oxide block ccpolymers. As is well known, the water-solubility cf such nonionic surface active agents generally varies depending upon the average amount of ethylene oxide units per mole of surfactant. Thus, for example, ethoxvlated nonionic surface active agents containing an average of ten or more ethylene oxide units per mole are generally readily water-soluble whereas those containing lower amounts of ethylene oxide, especially those containing from 1 to 5 ethylene oxide units per mole, are less water-soluble and thus may serve both as surface active agents and as solubility control agents. The second essential component of the mixture to be extruded is a rheological control agent, that is a material which, when dissolved or dispersed m water, gives a thickening or viscosity building effect. The rheological control agent maybe a clay, such as bentonite or laponite, or a water-soluble or water dispersible organic polymer. A wide variety of organic polymers are suitable for use in accordance with the invention. Such polymers may ¬ be wholly synthetic or may be semi-synthetic polymers derived from natural materials. Thus, for example, on class of polymers for use in accordance with the invention are chemically modified celluloses such as ethyl cellulose, methyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose, and hydroxyethyl cellulose. Wholly synthetic polymers which may be used in accordance with the invention include polyvinyl alcohols; water-soluble partially hydrolysed polyvinyl acetates; poiyacrylonitriles; polyvinyl pyrrolidones; water-soluble polymers of ethylenically unsaturated carboxylic acids, such as acrylic acid and methacrylic acid, and salts thereof; base-hydrolysed starch-polyacrylo itrile copolymers; polyacrylamides; polyether resins; and carboxypolymethylenes. A particularly preferred class of organic polymeric rheological control agents comprises the polysaccharide gums which have been found to assist in the extrusion process as well as being useful constituents of the block. A particularly preferred natural polysaccharide gum for use in accordance with the invention is guar gum, but other gums which may be employed include xanthan gum, tragacanth, carragheenan, etc and their semi-synthetic analogues as produced by fermentation. The gum serves as a cohesion agent and also as a solubility control agent and as a lubricant processing aid. However other solubility control agents may be employed in addition to the gum or other rheological control agent. Examples of such other solubility control agents are organic compounds of lower solubility than the anionic surface active agents and may vary in solubility from virtually completely insoluble to moderately soluble; the more insoluble being preferred for use in the present invention. As will be appreciated, a wide variety of solubility control agents may be employed and examples of preferred, generally insoluble agents include: waxes, such as waxes of natural origin, polyethylene waxes and amide waxes; long chain (e. g. containing more than 10 carbon atoms) fatty alcohols such as stearyl or behenyl alcohol; long chain, (e. g. containing more than 10 carbon atoms) fatty acids, such as stearic acid, and their salts; esters of long chain fatty alcohols with aliphatic carboxylic acids, such as stearyl acetate; esters of long chain fatty acids with mono or polyhydric alcohols, such as ethyl stearate or glycerol tristearate or mono-, di- or tri- glycerides of natural origin; fatty acid mono- and di- alkanolamides, such as coconut monoethanolamide; ethoxylated products of fatty acid mono- or di- ethanolamideε containing low amounts, e.g. 2 to 4 units, of ethylene oxide per mole; paradichlorobenzene; or long chain aliphatic hydrocarbons of natural or synthetic origin. Other preferred solubility control agents are generally insoluble perfume materials as discussed below. In general, the amount of solubility control agent present will depend upon three principal factors, the intended life of the block, the solubility of the solubility control agent and the amount of theology control agent. As will be appreciated, in order to obtain longer life more solubility control agent should be present and vice versa. Similarly, more of the more soluble solubility control agents will be required to obtain the same life than of the less soluble or wholly insoluble solubility control agents. Suitable fillers for use m the blocks of the invention are organic fillers such as urea; and inorganic fillers such as sodium carbonate, sodium bicarbonate, sodium chloride, sodium sulphate, borax, talc and calcium sulphate. In addition to the above essential ingredients, the blocks of the invention may contain other ingredients, especially colouring agents, perfumes, preservatives and lime scale-removing agents. The filler component may also comprise a water-softening agent such as, for example, inorganic water-softening agents-, such as sodium hexametaphosphate or other alkali metal polyphosphates, or organic water-softening or chelating agents such as ethylene-diamine tetraacetic acid and nitrilotriacetic acid and alkali metal salts thereof. Further the filler component may also comprise salts of polybasic metals, e. g. magnesium sulphate which serve to give improved character to the blocks as noted in our Application Serial No 2169612A Thus, the blocks of the invention will also generally contain a dyestuff or other colouring agent, such as a pigment, in order to impart a pleasant colouration to the water and also to indicate to the user when the block has exhausted (i. e. on exhaustion of the block the water becomes colourless). Accordingly, the block preferably contains water soluble dyestuff, suitably m an amount of up to 50% by weight, preferably in an amount of from 1 to 30% by weight. Suitable yestuffs include, for example, Acid Blue 9, Acid Blue 1, Acid Blue 7 and Acid Yellow 23. The blocks may also contain perfumes to impart an acceptable odour to the flushed water. The perfume may be a solid perfume, which term is intended to include micro-encapsulated perfumes (i. e. liquid perfumes contained in a water-soluble microcapsule) or other solid perfume materials such as paradichlorobenzene. Alternatively the perfume may be a liquid and in this case the term liquid perfume is intended to cover not only perfumes per se but solutions or perfumes in solvents therefor. The total amount of perfume should not be more than 20% by weight and is preferably from 2 to 10% by weight. It may be noted that the term "perfume" is intended to refer to any material giving an acceptable odour and thus materials giving a "disinfectant" odour such as pine oils, terpmolenes or paradichlorobenzene may be employed. It may be further noted that liquid perfumes are frequently substantially water-msoiuble and thus they may serve as a part of tr.e water-solubility control agent. In other words, a single material, such as pine oil, may serve both as perfume and a solubility control agent. The blocks in accordance with the invention may also contain germicides. Suitable germicides include, for example, formaldehyde release agents, iodophors and chlorinated phenols. These compounds may be present m the blocks m amounts of up to 10% by weight. Suitable lime scale-removing agents are acidic compounds such as citric acid, formic ac d, sulphuric acid, phosphoric acid and sulphamic acid. These, when present, suitably form up to 10% by weight of the block, especially in the case of solid acidic materials, such as citric acid, which then also serve as a filler. The blocks in accordance* with the invention are produced by an extrusion process comprising forming a mixture of the components for the block, extruding this mixture into rod or bar form and subsequently dividing the rod or bar into portions or blocks of the desired size. Conveniently the starting mixture contains a liquid component or a solid component capable of being wholly or partially liquefied under processing conditions, generally in an amount of up to 20% by weight, preferably from 3 to 15% by weight, of the .total mixture. Most conveniently such a liquid component comprises a perfume component and/or a solublity control agent component. Thus, for example, pine oil may serve not only as a perfume and solubility control agent but also as a processing aid. The blocks of the invention are suitably from 20 to 150 g s m weight preferably from 30 to 120 gms in weight. The invention further provides a method for cleansing a lavatory or urinal which comprises immersing n the water cistern of the lavatory or urinal a block produced in accordance with the invention. Blocks produced in accordance with the invention may also be used as containerized blocks (i. e. in dispensing containers) or as rim blocks for mounting in WC bowls. In order that the invention may be well well understood the following Examples are given by way of illustration only. In the Examples all parts are by weight. Lavatory cleansing blocks were prepared by extruding compositions having the formulations given in the Table below and cutting the extruded rod into blocks weighing about 50 gm. The blocks so obtained all had acceptable m-use lives when employed as free-standing lavatory cleaning blocks in lavatory cisterns. Table Example rn Ja-Hj-Li Silicate (--.ponite IDS) 10.0 |-Wifie ) Start* (Cferestir M) 10.0 Cuar Gui 10.0 Iaot an Gt* (feltrol TF) 10.0 lydroiy Ethyl Cellulose (Hatrosol lydroiy-propyl-βtliyl-cel lolose 10.0 (HeUHjόcel J) Table II The materials Marlon A390, Nansa HS80SJ, Nansa HS80GPF, Ufaryl DL90 and Ufaryl DL85 on all commercially available sodium dodecyl benzene sulphonate containing, as fillers, sodium sulphate, sodium t ipolyphosphate/sodium sulphate, magnesium sulphate/sodium sulphate, sodium sulphate and

Claims: CLAIMS 1. A process for the production of lavatory cleansing blocks by extruding a mixture of appropriate ingredienrs for the block into rod form and cutting the rod into pieces of the desired size, in which the mixture to be extruded comprises, based on the total weight of the mixture; (i) from 5 to 85% by weight, of one or more anionic surface active agents; and (ii) from 0.5 to 40% by weight, of one or more rheological control agents. 2. A process as claimed in Claim 1 in which the anion i surfactant is an alkali metal alkyl benzene sulphonate. 3. A process as claimed in claim 1 and claim 2 in which rheological control agent is a polysaccharide gum. 4. A process as claimed in any one of the preceding claims in which the mixture to be compressed also contains: (iii) up to 20% by weight of one or more solubility control agents; and/or (iv) up to 75% by weight of one or more fillers or builders. 5. A process as claimed in claim 1 substantially as hereinbefore described.

Inventors: BLACK STEVEN JOHN FARRELL, MARSHALL JOHN, WILSON BRIAN MURIE, BLACK, STEVEN, JOHN, FARRELL, MARSHALL, JOHN, WILSON, BRIAN, MURIE
Applicants: JEYES LTD, JEYES LIMITED
Application year: 1991
Main classification: C11D17
IPC codes: C11D1, C11D3, C11D17