AU3416699A - Toilet cleaning blocks - Google Patents

Description

WO99/53012 PCTIEP99/01899 TOILET CLEANING BLOCKS Technical Field: 5 The present invention relates to toilet blocks. Background of the Invention: 10 Toilet blocks are blocks of a slowly soluble material either in containers attached to the rim of a toilet (so called 'rim-blocks') or in the cistern of the toilet (so-called 'cistern-blocks'). The slowly soluble material can comprise a mixture of surfactant and optional filler as well as 15 various functional ingredients such as perfumes dyestuffs and bleaches. Both types of block dissolve slowly in use: the rim block dissolving in the flush water that meets with it when the toilet is flushed and the cistern block dissolving in the water contained in the cistern between 20 flushes. Toilet blocks containing bleaching agents based on halogen release agents are known to be unstable, one way of countering this effect has been to include a source of 25 certain metal ions as described in EP 0 341 836. We have found a problem associated with toilet blocks, in that when toilet blocks are stacked together heating can occur in the blocks in the center of the stack. Thus large 30 numbers of blocks can not be stacked together as the blocks in the center of the stack can appear scorched. This scorching of the central blocks in a stack makes transport of toilet blocks difficult.

WO99/53012 PCT/EP99/01899 - 2 The present invention mitigates the problem of thermal heating within toilet blocks. Description of the Invention: 5 Accordingly, the present invention provides a toilet block comprising solid bleaching agent or precursor thereof wherein 75% of the granules of said bleaching agent have a granule size greater than 400 microns. 10 The present invention also relates to a method of preventing thermal heating within a toilet block by incorporation of a bleaching agent wherein 75% of the granules of said bleaching agent have a granule size greater than 400 microns. 15 Detailed Description of the Invention: Bleaching Agents: 20 The toilet blocks of the invention contain a bleaching agent having a defined granule size. The blocks are thermally stable when stored in bulk. The toilet blocks of the invention contain a bleaching 25 agent. Typically the blocks comprise up to 50% by weight of an at least sparingly water soluble bleaching agent. Typical 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 30 precursor which produces a bleaching agent unless the context demands otherwise.

WO99/53012 PCT/EP99/01899 - 3 It is preferred if 85% of the bleaching agent or precursor thereof have a granule size greater than 400 microns, more preferably 95% of the particulate bleaching agent or precursor thereof having a granule size greater than 400 5 microns. It is further preferred if 95% of the bleaching agent or precursor thereof has a granule size greater than 200 microns. 10 In the context of the present invention the term granule encompasses material of both a granular and particulate nature. 15 It is advantageous if 90% of the bleaching granules have a granular size less than 2000 microns, more preferably 95% of the particles having a granular size less than 2000 microns, most preferably 99% of the granules having a granule size less than 2000 microns. 20 Suitable bleaching agents active-halide and active-oxygen bleaching agents, particularly the so-called 'halogen release agents' 25 Chlorine bleaching agents are preferred. Suitable water soluble, active chlorine, bleaching agents used in accordance with the invention include chlorinated cyanurates, phthalimides, p-toluene sulfonamides, azodicarbonamides, hydantoins, glycoluracils, amines and 30 melamines. The alkali metal salts of cyanurates are preferred. A particularly preferred bleaching agent is sodium dichlorocyanurate (NaDCCA). The bleaching agent is WO99/53012 PCT/EP99/01899 - 4 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. 5 The bleaching agent may be coated and/or co-granulated with polymer to further mitigate the risk of thermal heating. Suitable polymers include soluble or insoluble polycarboxylate/co-polymers of the polycarboxylic acid, both 10 in acidic form or neutralized with alkaline and/or earth metal ions. The polymer molecular weight preferably ranges from 200 to 3000000, more preferably from 3000 to 1000000 most preferably from 50000 to 500000. 15 It is particularly preferred if the polymer used is polyacrylic acid. If present it is preferred if the ratio of bleaching agent to polymer is from 1:10 to 10:1. Especially preferred polymers Sokalan CP5 (ex BASF or 20 Aktiengeselishaft), AS 175 (ex ALCO) both in liquid and granular form and Norasol SPO2M (ex Norsohass) both in liquid and granular form. Surfactants: 25 A surfactant may be present in the toilet block. The surfactant component of the block may be anionic or nonionic in nature. The surfactant serves to provide a cleansing and foaming effect and may, also act synergistically with the 30 polymer component. Typically, surfactant comprises up to 50%wt of the composition. Preferably, the surfactant component comprises one or more anionic surface active agents, optionally in combination WO99/53012 PCTIEP99/01I899 - 5 with one or more nonionic surface active agents. Suitable anionic surface active agents include alkali metal or ammonium alkylaryl sulphonates (especially alkyl benzene sulphonates), alkane sulphonates, alkyl sulphates and 5 sarcosinates. We have determined that improved foaming properties are obtained by the use of a surfactant system which comprises primary alkyl sulphate (PAS) together with other anionic 10 surfactants. Preferably the present invention provides a lavatory cistern block comprising 1-15%wt (more preferably l-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 15 advantageous in that it reduces the stickiness of the block during manufacture. The blocks with 1-5% PAS show improved wear characteristics. Preferably said other anionic surfactants is a sulphonate. 20 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. PAS is also believed to be environmentally more acceptable than 25 alkyl benzene sulphonate. Suitable nonionic surfactants include polyethoxylated fatty alcohols, polyethoxylated fatty acids, polyethoxylated alkyl phenols, amine oxides and ethylene oxide/propylene oxide 30 block copolymers. The total amount of surfactant when present, may lie within wide limits. In practice, the surfactant will generally for WO99/53012 PCT/EP99/01I899 - 6 10 to 70% by weight of the composition, but more preferable that surfactant comprises from 20 to 50% by weight thereof. Process Aids: 5 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 10 ethylenically unsaturated carboxyl group-containing monomers) and polybutene. One particularly suitable processing aid is an alkoxylated alcohol. It is preferred that the alkoxylated alcohol is an 15 ethoxylated alcohol. The preferred level of alkoxylated alcohol is 0.75-2%wt. The preferred ethoxy chain length is 40-60 with an average ethoxy chain length of around 50 being preferred. Suitable materials include Empilan KM 50/KF (TM) ex. Albright & Wilson. Another suitable process aid is a 20 PEG monostearate. PEG 4000 Monostearate (100%) ex DAC is a suitable raw material. Polymers: 25 In addition to the polymers used to coat/mix with the bleaching agent polymers may be present in the formulation to prevent rapid dissolution of the block. If present preferred polymers are polycarboxylic acids derived from one or more ethylenically unsaturated carboxyl group-containing 30 monomers, especially ethylenically unsaturated carboxylic acids such as acrylic acid or maleic acid. The carboxyl group-containing monomers may be polymerized alone or in combination with other ethylenically unsaturated WO99/53012 PCT/EP99/01899 7 monomers. Preferred polymers are polymers of acrylic or methacrylic acid or maleic anhydride, or a co-polymer of one or more of the same either together or with other monomers. In general, polymers derived largely or wholly from the 5 acidic monomers are preferred. Suitable polymers include polyacrylic acid, polymaleic anhydride and copolymers of either of the aforementioned with ethylene, styrene and methyl vinyl ether. 10 It is preferred that the polymer is crosslinked. Such materials are available from a number of sources including materials available under the tradename CARBOPOL (TM) from B. F. Goodrich Company, the tradename SOKOLAN (TM) from the 15 BASF Corporation and under the tradename POLYGEL (TM) from 3V Sigma. The polymer is suitably present in an amount of from 0.5 to 20% by weight, more preferably from 1 to 5% by weight, most 20 preferably around 2-3% by weight thereof. Fillers: Typically, blocks according to the present invention 25 comprise 0 to 50% by weight of an inert non-polymeric and/or electrolyte filler. Preferably blocks contain 5-50%wt, more preferably 10-30% of filler. Suitable fillers include one or more of urea, sodium, 30 magnesium and calcium carbonates, sodium chloride, borax, talc and sodium, magnesium and calcium sulphates. Preferred ionic fillers include sodium sulphate. Preferred inert, non-polymeric fillers include calcium carbonate.

WO99/53012 PCT/EP99/01899 - 8 Typical levels of total filler range from 10-40%wt on product in total. If the toilet block is an in-cistern blocks, it is 5 beneficial to use 10-30%wt of an ionic filler as the sole filler present to ensure stability and solubility of the block. For mixed filler systems, preferred levels of filler are 10-20%wt on product of ionic filler and 10-20% on product of inert filler. It is particularly preferred to 10 use an approximately 50:50 mixture of sodium sulphate and calcium carbonate as the filler. For mixed filler systems typical levels in product are 15%wt of each of calcium carbonate and sodium sulphate. 15 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 20 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. 25 Suitable oily perfumes can be easily selected by testing them in combination with the water-soluble, active chlorine, bleaching agent. Examples of suitable bleach-stable perfumes are Verdeo 898, 30 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. The most preferred perfume is Green Tank Harder (TM) ex. Givaudan Roure.

WO99/53012 PCT/EP99/01899 9- Minors: Minor components will generally be present but are optional. 5 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. We have determined that 'Sudangelb 150' (TM) ex. Sandoz is an acceptable colouring agent as are 10 Colanyl Green (TM) ex Hoechst and Dispers Blue (TM) ex BASF. A particularly preferred colouring agent is P. Green (CI 74260). Titanium dioxide is an acceptable whitener. Levels of colouring agents and/or whiteners as typically below 5%wt. For colouring agents levels are typically in the 15 range 0.0001-0.1%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 20 or a derivative thereof, nitrolotriacetic acid, phosphonates of polyphosphates, metasilicates, boroheptonates, s.s thylene-diamino disuccinate, dipicolinic acid, 2 phosphonobutane-l,2,4-tricarboxylic acid, or lower molecular weight polymeric materials capable of inhibiting crystal 25 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. An optional minor component is a foam-boosting surfactant. 30 Suitable surfactants include amine oxides.

WO99/53012 PCTIEP99/01I899 - 10 Process: As noted above, compositions in accordance with the invention are formed by an extrusion process in which the 5 mixture of the components which comprises is extruded as a plastified mass through an aperture to form a billet. It is preferred that if the compositions of the invention are used as free-standing lavatory cleansing blocks, they 10 have a weight from 30 to 150 grams, preferably 40-80 grams. Preferred Compositions: Preferred embodiments of the invention provide a slow 15 release lavatory cleansing block comprising: a) 1-5% wt primary alkyl sulphate; b) 30-50% wt alkyl benzene sulphonate; c) 10-30% wt NaDCCA wherein 75% of the granules of 20 NaDCCA have a granule size greater than 400 microns; d) 10-30% wt sodium sulphate, calcium carbonate or a mixture thereof; e) 2-10% wt oily liquid perfume; 25 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 30 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 WO 99/53012 PCTIEP99/01899 - 11 Examples: Blocks were produced by mixing the raw materials together with the exception of perfume and NaDCC. The perfume was 5 then added to the mix followed by the addition of NaDCC. The resulting dough was extruded and then cut into blocks of the desired shape. Table 1 Example wt% Ingredient A 1 g,,, ....... ..... ......... ..... ..... AS37.0 37.0

PAS

2 4.5 4.5 Polygel DB 3 3.0 3.0 NaDCCA 4 25.0 NaDCCA 5 25 Sodium sulphate 13.25 13.15 Perfume 4.0 4.0 Minors to 100 to 100 10

ABS

1 is Alkyl benzene sulphonate NANSA HS 80/LPF (TM) ex Albright & Wilson

PAS

2 is Primary alkyl sulphate Empicol LZ-V (TM) ex Albright & Wilson 3 15 Polymer is Polygel DB (TM) high molecular weight-water insoluble, partially cross linked acrylic acid polymer ex Sigma NaDDCA Granules with fines present ie greater than 30% of the granules have a particulate size of less 20 than 400 microns.

WO99/53012 PCTIEP99/01899 - 12 NaDCCA 5 Granules with fines removed ie 99% of the material has a particulate size greater than 400 microns. 5 To monitor the thermal heating profile of the blocks twelve blocks were stacked together and wrapped in tin foil. The blocks were heated at 60 0 C for 180 hours. A thermometer inside the block pallet assessed the pallet temperature at different times. 10 Temperature oC 24 hours_ 48 hours 72 hours 96 hours Example A 59 75 72.5 69 Example 1 55 67.5 67 66

Claims (9)

1. A toilet block comprising a solid bleaching agent or precursor thereof wherein 75% of the granules of said 5 bleaching agent have a granule size greater than 400 microns.

2. A toilet block according to claim 1 in which the 95% of the solid bleaching agent or precursor thereof has a 10 granule size greater than 400 microns.

3. A toilet block according to claim 1 or claim 2 in which the bleaching agent is a halogen release agent. 15

4. A toilet block according to any preceding claim in which the bleaching agent is selected from chlorinated cyanurates, phthalimides, p-toluene sulfonamides, azodicarbonamides, hydantoins, glycoluracils, amines and melamines. 20

5. A toilet block according to any preceding claim in which the bleaching agent is sodium dichlorocyanurate (NaDCCA). 25

6. A toilet block according to any preceding claim which further comprises a surfactant.

7. A toilet block according to any preceding claim, further comprising a processing aid selected from mineral oil, 30 silicone oil, water insoluble esters other than those derived from ethylenically unsaturated carboxyl group containing monomers, polybutene and alkoxylated alcohols. WO99/53012 PCT/EP99/01899 - 14

8. A toilet block according to any preceding claim comprising: a) 1-5% wt primary alkyl sulphate; 5 b) 30-50% wt alkyl benzene sulphonate; c) 10-30% wt particulate NaDCCA 75% of which has a granule size greater than 400 microns; d) 10-30% wt sodium sulphate, calcium carbonate or a mixture thereof; 10 e) 2-10% wt oily liquid perfume and; f) 0.1-2% wt of a heavy metal ion deactivating agent selected from sodium silicate, magnesium silicate, or sodium periodate. 15

9. A method of preventing thermal heating within a toilet block by incorporation of a particulate bleaching agent wherein 75% of the granules of said bleaching agent have a granule size greater than 400 microns. 20