LAVATORY CLEANSING COMPOSITIONS

Abstract: A lavatory cleansing block comprising at least two phases one phase (phase 1) comprising a water insoluble salt as at least 50 wt% of the salt present within that phase and a second phase (phase 2) comprising a perfume and a water soluble salt such that the salts in both phases have the same anion.

Description: LAVATORY CLEANSING COMPOSITIONS Technical Field This invention is concerned with lavatory cleansing blocks which may be used to clean and/or perfume the flush water of a lavatory or urinal . Background to the Invention The use of toilet blocks to impart cleansing and/or other components to the flush water of a lavatory or urinal is well known. Such compositions may, for example, be immersed in the water of a lavatory or held under the rim of a toilet, in a suitable holder, for intermittent contact of the solid material with flush water. For convenience these two approaches will be referred to herein respectively as 'cistern-blocks' and 'rim-blocks' In recent years it has become commonplace for toilet blocks to contain a halogen release agent or other bleaching agent . From EP 0206725 it is clear that halogen release agents are, by their nature, powerful chemically reactive species, serving as halogenating or oxidising agents and it is consequently difficult to incorporate bleach-sensitive components such as perfumes and dyestuffs into blocks which contain bleaching agents. Toilet blocks in which two incompatible components are separated by placing them in different phases of the toilet block are described in EP 0 101 402 (Henkel) . We have found that with dual phase toilet one phase tends to dissolve faster than the other phase leading to a disparity in the dosing of the ingredients in the final flushes of the toilet . Brief Description of the Invention We have determined that improved toilet blocks can be formulated in which the problem of uneven dissolution between the phases of a multiphase block can be mitigated. Accordingly, the present invention provides a lavatory cleansing block comprising at least two phases one phase (phase 1) comprising a water insoluble salt as at least 50 wt% of the salt present within that phase and a second phase (phase 2) comprising a perfume and a water soluble salt such that the salts in both phases have the same anion. The invention also relates to a process for producing the toilet blocks, described in the above paragraph, the process comprising the step of co-extruding the two phases to form a block. Detailed Description of the Invention In order that the invention may be further understood the following description details preferred and optional features of the invention. Salts The present invention preferably relates to a dual phase block. Phase 1 of the block comprises a water insoluble salt as at least 50 wt% of the salt present, m the context of the present invention water insoluble salt refers to salts having a maximum solubility parameter of 0.05 gram per lOOcc of water at 25°C. The second phase (Phase 2) of the block comprises a perfume and a water soluble salt. The term water soluble salt refers to salts having a solubility parameter of at least 0.5 gram per lOOcc of water at 0°C, more preferably greater than 1 gram per 100 cc of water. The salts m both phases should have the same anion. Other salts with differing anions may also be present within each phase. However, it is highly preferable if phase 1 does not contain a water soluble salt having the same anion as the water insoluble salt . The total level of water soluble salt having the same anion as the water insoluble salt within phase 2 is from 1 to 10 wt% of the total level of ingredients present m phase 2. It is preferred if phase 2 further comprises a water insoluble salt having the same anion as the water soluble salt. More preferably the ratio of water soluble salt and the water insoluble salt both having the same anion within phase 2 of the toilet block is from 5:1 t 1:5. Most preferably the ratio of water soluble salt and the water insoluble salt both having the same anion within phase 2 of the toilet block is from 3:2 to 2:3. A preferred water soluble salt for use with the present invention is sodium carbonate. A preferred water insoluble salt for use with the present invention is calcium carbonate. The total level of water insoluble salt in phase 1 is from 1 to 10 wt% of the total level of ingredients present in phase 1. Blocks according to the present invention comprise 5 to 50 wt% to by weight of salt as a sum of the total ingredients of both phases inclusive of the anion present, more preferably 10-30 wt%. Alcohol Ethoxylate The toilet blocks according to the invention may include an alcohol ethoxylate. The alcohol ethoxylate preferably used in the present invention is ethoxylated with 8 or less moles of alkylene oxide, more preferably the alcohol ethoxylate is ethoxylated with 5 or less moles of alkylene oxide. Preferably the alcohol ethoxylate has a carbon chain length of C 8 to C 22 , more preferably from C 8 to Cι 6 Preferably the alcohol ethoxylate is branched. It is preferred if the alcohol ethoxylate has an H.L.B of 12 or less, more preferably an HLB of 10 or less, most preferably of 8 or less. The alcohol ethoxylate should preferably have a cloud point of less than 65 when measured in water at a 1% solution. Preferably, the level of alcohol ethoxylate within the block is less than 5 wt% of the total weight of the block. More preferably the alcohol ethoxylate is in a separate phase to the perfume (that is phase 1) . It is advantageous if the level of alcohol ethoxylate is from 0.5 to 6 wt % of the weight of the total composition (i.e. both phases), more preferably from 1.5 to 4 wt% of the weight of the total composition. Bleaching Agents Typically the blocks comprise up to 50% by weight of a at least sparingly water soluble bleaching agent. Typically levels of bleaching agents are 2-30% wt on product. For the purposes of the present specification the term bleaching agent is used to mean both a bleaching agent and a precursor which produces a bleaching agent unless the context demands otherwise . Suitable bleaching agents active-halide and active-oxygen bleaching agents, particularly the so-called 'halogen release agents'. Chlorine bleaching agents are preferred. Suitable water- soluble, active chlorine, bleaching agents used in accordance with the invention include chlorinated cyanurates, phthalimides, p-toluene sulphonamides, azodicarbonamides, hydantoins, glycoluracils , amines and melamines. The alkali metal salts of cyanurates are preferred. A particularly preferred bleaching agent is sodium dichlorocyanurate (NaDCCA) . The bleaching agent is typically present in an amount of 10-30% and most preferably at around 25%. Oxidan DCN/WSG (TM) ex Sigma has been found to be a suitable bleaching agent . In a particularly preferred embodiment of the invention the bleach resides in the same phase as the water insoluble salt (phase 1) . Anionic Surfactant Preferably, the composition will also contain a surfactant component which is anionic in nature. This surfactant serves to provide a cleansing and foaming effect . Suitable anionic surface active agents include alkali metal or ammonium alkylaryl sulphonates (especially alkyl benzene sulphonates) , alkane sulphonates, alkyl sulphates and sarcosinates . We have determined that improved foaming properties are sometimes obtained by the use of a surfactant system which comprises primary alkyl sulphate (PAS) together with other anionic surfactants. Preferably the present invention provides a lavatory block comprising 1-15% wt (more preferably 1-5% wt) of a primary alkyl sulphate and 15-50%wt (more preferably 30-50%wt) of other anionic surfactants. We have determined that the use of this mixed surfactant system is advantageous in that it reduces the stickiness of the block during manufacture. The blocks with 1-5% PAS show improved wear characteristics. Preferably the other anionic surfactants are sulphonates. Suitable sulphonates include alkyl benzene sulphonate (ABS) . It is believed that the combination of relatively low levels of PAS together with higher levels of ABS promotes the foaming and the perfume delivery from the block. The total amount of surfactant when present, may lie within wide limits. In practice, the surfactant will generally be for 10 to 70% by weight of the composition, but more preferable that surfactant comprises from 20 to 50% by weight thereof. Process Aids As will be described in further detail below extrusion is the preferred method of manufacture. Optionally, the blocks according to the invention further comprise a processing aid to assist in extrusion. Suitable processing aids include oils (including both mineral and silicone oils) , esters (other than those derived from ethylenically unsaturated carboxyl group containing monomers) , alcohol ethoxylates and polybutene. Perfume Preferably, the blocks comprise 2-15%wt of a hydrophobic oily liquid perfume. The blocks more preferably comprise, 2-10%, more preferably 3-6% wt of the perfume. Levels of around 4% wt perfume are particularly preferred. This oily perfume is typically of the kind described in the European patent application EP 167,210. It will be understood that the liquid oily perfume must be stable in the presence of the water-soluble, active chlorine, bleaching agent. Suitable oily perfumes can be easily selected by testing them in combination with the water-soluble, active chlorine, bleaching agent . In some instances, the toilet block may comprise two perfumes in this case it is preferable if the perfume present in each phase is at least 80 wt% of the total perfume present in that phase. More preferably different perfumes are present in phases. Examples of suitable bleach-stable perfumes are Verdeo 898, Bonanza 048 and Ponderosa 431 all ex IFF, and LB 132 ex Quest . Particularly preferred perfumes are Icebreaker Super Mod, Oxygen Supra Mod, Motebianco Supra and lemonfit Supra (all TM) ex Givaudan Roure . Minors Minor components will generally be present but are optional. These include colouring agents, and/or whiteners . These materials should be chosen such that they are compatible with the bleaching agent and do not react therewith to a significant extent . Titanium dioxide is an acceptable whitener. Levels of colouring agents and/or whiteners as typically below 5% wt . Further enhancement of the product may be obtained by the additional use of chelating agent, sequestrant or water- softening agent such as ethylene diamine tetra-acetic acid or a derivative thereof, nitrolotriacetic acid, phosphonates of polyphosphates, metasilicates, boroheptonates , s.s- thylene-diamino disuccinate, dipicolinic acid, 2- phosphonobutane-1 , 2 , 4-tricarboxylic acid, or lower molecular weight polymeric materials capable of inhibiting crystal growth. Further reducing agents, such as alkali metal metabisulphates may be present to assist in the reduction of staining due to metals such as iron. Typically, one phase of the blocks according to the present invention comprise 1-15% wt , more preferably 2-10% of a dyestuff on a carrier. It is preferable if the other phase of the block is totally coloured. In both cases it is preferable if the dye is water soluble. Polymers A water-insoluble, gelling polymers may be used in compositions of the invention, these are polycarboxylic acids derived from one or more ethylenically unsaturated carboxyl group-containing monomers, especially ethylenically unsaturated carboxylic acids such as acrylic acid or maleic acid. Suitable polymers include polyacrylic acid, polymaleic anhydride and copolymers of either of the aforementioned with ethylene, styrene and methyl vinyl ester. If present it is preferred that the polymer is cross-linked. Polygel DB (TM) ex 3V Sigma, a cross-linked high molecular weight polyacrylate, has been found to be a suitable material at an inclusion level of around 2-3%wt. Process Compositions in accordance with the invention may be produced by a variety of routes. For example, they may be prepared by a so-called "hot -melt" process comprising melting the fusible constituents of each phase of the block followed by adding the other components, and subsequently casting the melt into moulds or are formed into the desired final shape by a compression technique, i.e., a technique involving the steps of forming a mixture of the ingredients of the compositions and then compressing that mixture into the desired shape. The two phases so formed are then compressed together. An especially preferred process is an extrusion process in which mixtures of the components of each phase are co- extruded into a solid bar or rod which is subsequently cut into pieces of the desired size. It may be noted that when the compositions of the invention are used as free-standing lavatory cleansing blocks, these suitably have a weight from 30 to 150 gms . When extruding a solid composition it is generally advantageous, as noted above, that some lubricant component or process aid be present to facilitate extrusion. The weight of each phase is preferably approximately the same as each other (approximately in this context meaning that the weight of each phase varies within 20% from each other, more preferably within 10%) . Compositions in accordance with the invention may also be formed into the final desired shape by a tabletting technique . As used herein the term block is not intended to limit the shape of the eventual product . For cistern blocks the rod is cut into lengths which are short relative to their diameter. The invention also provides a method of cleaning a lavatory or urinal using a block of a composition in accordance with the invention. In order that the invention may well be understood, the following Examples are given by way of illustration only. Examples of the invention are illustrated by a number, comparative Examples are illustrated by a letter. Examples Toilet blocks were formed by an extrusion process in which the mixture of the components of each phase were co-extruded as a plastified mass through an aperture to form a billet and said billet is cut into tablets of appropriate size. The toilet blocks had the following formulation: ABS 1 Nansa HS 80/L ex Albright & Wilson PAS 2 PAS-Empicol LZ-V ex Albright & Wilson Coloured granules sodium carbonate ex Crosfield Alcohol ethoxylate 2E0 5 Loradac 2-24 2EO ex DAC. The in-use lifetime of each block was measured by placing in a toilet, flushing 250 times and measuring the residual weight of the block. It can thus be seen that the disparity between the two phases of the toilet block is less with the blocks of the invention.

Claims: CLAIMS 1. A lavatory cleansing block comprising at least two phases one phase (phase 1) comprising a water insoluble salt as at least 50 wt% of the salt present within that phase and a second phase (phase 2) comprising a perfume and a water soluble salt such that the salts in both phases have the same anion. 2. A lavatory cleansing block according to claim 1 in which phase 2 further comprises a water insoluble salt having the same anion as the water soluble salt. 3. A lavatory cleansing block according to claim 2 in which the ratio of water soluble salt and the water insoluble salt both having the same anion is from 5:1 to 1:5. 4. A lavatory cleansing block according any preceding claim in which phase 2 further comprises a bleaching material . 5. A lavatory cleansing block according to claim 4 in which the bleaching agent is an halogen release agent . 6. A lavatory cleansing block according to claim 5 in which the bleaching agent is sodium dichlorocyanurate (NaDCCA) . 7. A lavatory cleansing block according to any preceding claim m which the water soluble salt is sodium carbonate. 8. A lavatory cleansing block according to any preceding claim in which the water insoluble salt is calcium carbonate . 9. A lavatory cleansing block according to any preceding claim in which the level of water soluble salt having the same anion as the water insoluble salt within phase 2 is from 1 to 10 wt% of the total level of ingredients present in phase 2. 10. A toilet block according to any preceding claim in which the total level of water insoluble salt in phase 1 is from 1 to 10 wt% of the total level of ingredients present in phase 1. 11. A lavatory cleansing block according to any preceding claim in which phase 1 further comprises an alcohol ethoxylate, ethoxylated with 8 or less moles of alkylene oxide . 12. A process for producing a toilet block according to any preceding claim in which the process comprises the step of co-extruding the two phases to form the block.

Inventors: GALLI MARCO, OLIVA MARCO, GALLI, MARCO, OLIVA, MARCO
Applicants: GALLI MARCO, LEVER HINDUSTAN LTD, OLIVA MARCO, UNILEVER NV, UNILEVER PLC, GALLI, MARCO, HINDUSTAN LEVER LIMITED, OLIVA, MARCO
Application year: 2000
Main classification: C11D17
IPC codes: C11D1, C11D3, C11D7, C11D11, C11D17, E03D9