EP1553162A1 - Lavoratory blocks - Google Patents

Abstract

The invention provides a lavatory cleansing and fresheningblock comprising a solid phase and a gel phase, in which:
the gel phase contains from 2% to 90% by weight perfume(based on the total weight of the gel phase) and ispositioned on the surface of the solid phase.

Description

Field of the Invention
• The present invention relates to lavatory blocks.
Background and Prior Art
• Lavatory blocks are known in the art and are typicallyconfigured to provide an automatic and sustained release ofactive ingredients to the lavatory environment. Forexample, they may be suspended in a container under the rimof a lavatory bowl or urinal such that, during a flushingcycle, water from the cistern flows over the block therebydissolving a portion of the block and releasing activeingredients of the block into the lavatory bowl.
• In recent years it has become desirable that lavatoryblocks contain a number of active ingredients in order toprovide multiple lavatory care benefits such as cleansing,disinfection and fragrancing.
• Formulating and processing blocks with multiple activeingredients can lead to problems due to the physical and/orchemical incompatibility of such ingredients. For example,it has become commonplace for lavatory blocks to contain ahalogen release agent or other bleaching agent. Suchmaterials are powerful chemically reactive species, whichare difficult to combine with other oxidation sensitivecomponents (such as perfumes), particularly since blocks are commonly made by extrusion which subjects theingredients to elevated temperatures and pressures.
• WO00/23558 describes how it is possible to provide a viabletwo-part lavatory cleansing block containing bleach andbleach-incompatible substances by extruding twocompositions, only one of the compositions containing thebleach, and the other composition containing a componentwhich is incompatible with the bleach, and ensuring thatthe two compositions do not have a common hydrophobecomponent. This is said to prevent the migration of thebleach sensitive component. Preferably the block parts areco-extruded side-by-side. A problem with such co-extrusionis that it places constraints on the formulation and thephysical properties of the constituent block parts. Forexample, it is difficult to co-extrude parts ofsignificantly different rheologies.
• Furthermore, it is desirable that lavatory blocks continueto produce lavatory care benefits (such as fragrancing)throughout the useful life of the block, which is typicallyaround 3 to 4 weeks under normal domestic use conditions. Aproblem with the incorporation of high levels of perfumeinto blocks formed by an extrusion process is that suchincorporation may produce an overplasticised or stickyformulation consistency that is difficult to extrude. Also,perfume materials are normally hydrophobic and high levelsmay tend to ooze out from the block during manufactureand/or storage.
• US 5,759,974 describes a WC stick with a relatively highfragrance content in a cast core. This is said to have theadvantage of the possibility of incorporating very largequantities of perfume in the core. The stick ismanufactured by extruding a hollow shell, cutting the shellto its final length, and placing on a support in such a waythat the moulding is closed underneath. The shells are thenfilled with the molten core material containing the perfumeby means of a casting trolley. A problem with thismanufacturing method is that it is difficult to scale upand/or operate as a continuous process.
• WO03/0426 describes how the fragrance life of an in-the-bowl(ITB) toilet article may be extended by placing theperfume in the second chamber of a dual chamber housing sothat the perfume is not in the path of the flushing toiletwater. The first chamber has an inlet and an outlet openingfor water flow and typically contains a cleaning,disinfectant or anti-limescale composition in solid blockform which fits into the chamber. A problem with thisproposal is that the dual chamber housing is an expensiveconfiguration to manufacture. Also, since the perfume isplaced within a gel system which is deposited in the secondchamber of the housing, this means that the entire housingwill need replacing by the consumer once the perfume isexhausted.
• The underlying objective of the present invention is toresolve one or more of the problems outlined above.
Summary of the Invention
• The present invention provides a lavatory cleansing andfreshening block, comprising a solid phase and a gel phase,in which the gel phase contains from 2% to 90% by weightperfume (based on the total weight of the gel phase) and ispositioned on the surface of the solid phase.
• The gel phase releases perfume during as well as betweenthe flushes
Detailed Description of the InventionProduct Form and Process
• Preferably the solid phase of the block according to theinvention has a recess moulded on an outer surface in whichthe gel phase is positioned.
• The solid phase of the block according to the invention ispreferably formed by a process which includes extrusion.
• A preferred process used to form the solid phase of theblock is an extrusion process in which a mixture of theconstituent ingredients of the solid phase is extruded intoa continuous bar of solid phase which is subsequently cutinto pieces of the desired size.
• The solid phase may be in the form of a single, homogeneouscomposition, or alternatively may be in the form of one ormore layers. Such a multi-layered solid phase may suitablybe produced by extrusion of the layers as complementaryshapes which are brought together, or preferably by co-extrusionof the two layers side-by-side into a continuousbar as above. The provision of a multi-layered solid phaseis advantageous because it enables incompatible componentssuch as bleach and dye, or bleach and bleach activator, tobe segregated by placing them in different layers, therebyenhancing stability and performance of the block.
• The solid phase of the block preferably has a recessmoulded on an outer surface thereof, more preferably alongitudinal surface. Preferably the recess extends alongthe entire length or width of the longitudinal surface ofthe solid phase of the block as a strip or groove.
• The recess may be moulded on an outer longitudinal surfaceof the solid phase of the block by stamping, or preferablyby extruding the constituent ingredients of the solid phasethrough a specially shaped extruder head so that the recessis formed in an outer longitudinal surface of the solidphase as it is extruded. This latter process isadvantageous since it avoids the need for a separaterecess-moulding step and so enables the overallmanufacturing process of the block to be operatedcontinuously.
• The gel phase is positioned in the recess of the solidphase. Preferably it is put into position by injection intothe recess. In a more preferred process, the constituentingredients of the gel phase are heated, mixed and dosedthrough a nozzle into the recess of the solid phase.
• In a most preferred process, the constituent ingredients ofthe solid phase are extruded through a specially shapedextruder head to form a recess as described above, and theextrudate so formed is mounted to travel upon a beltconveyor which is arranged so that the gel phase may beinjected continuously into the recess of the solid phase asit travels along the belt conveyor, for example by dosingthe gel phase into the recess through a nozzle as describedabove. Cooling and cutting of the gel-filled extrudate soformed may then take place to produce the final lavatoryblock according to the invention. Again this enablescontinuous operation of the block manufacturing process.
• Fig 1 depicts an extruded block having a recess mouldedalong the entire length of a longitudinal surface of thesolid phase 1, which is filled with thegel phase 2. Fig. 2depicts an extruded block having a recess moulded along theentire width of a longitudinal surface of the solid phase1, which is filled with thegel phase 2.
• The weight ratio of solid phase to gel phase in the blockaccording to the invention suitably ranges from 40:1 to 5:1, preferably from 30:1 to 5:1, more preferably from 25:1to 10:1, more preferably from 25:1 to 12.5:1.
Solid Phase
• Suitable substances used to form the solid phase includesurfactants, hygiene agents, fillers, whiteners andcomplexing agents.
Surfactants
• Surfactants serve to provide a cleansing and foaming effect.The total amount of surfactant, when present, will generallyrange from 10 to 70wt%, more preferably from 20 to 50wt% (byweight based on the total weight of the solid phase).
• Anionic surfactants are preferably used. Suitable anionicsurfactants include alkali metal or ammonium alkylarylsulphonates (especially alkyl benzene sulphonates), alkanesulphonates, alkyl sulphates and sarcosinates.
• Improved foaming properties are obtained by the use of asurfactant system which comprises primary alkyl sulphate(PAS) together with other anionic surfactants.
• Preferably the solid phase comprises from 1 to 20wt%, morepreferably from 5 to 15wt% of a primary alkyl sulphate (byweight based on the total weight of the solid phase), andfrom 5 to 40wt%, more preferably from 10 to 35wt%, even morepreferably from 15-35% of other anionic surfactants (byweight based on the total weight of the solid phase).Preferred other anionic surfactants are sulphonate anionicsurfactants, such as alkyl benzene sulphonates (ABS).
Hygiene agents
• Hygiene agents may be used in the solid phase to inhibitgerms and keep the lavatory clean. The total amount of suchmaterials, when present, will generally range from 5 to50wt%, more preferably from 5 to 30wt% (by total weight ofhygiene agent based on the total weight of the solid phase).
• Preferred hygiene agents for use in the block according tothe invention are bleaching agents, optionally incombination with one or more bleach activators.
• Suitable classes of bleaching agent include materials whichrelease active halogen and materials which release activeoxygen. Examples from these classes include chlorinatedcyanuric acid derivatives such as sodiumdichloroisocyanurate; halogenated hydantoins such as 1,3-dichloro-5,5-dimethylhydantoin , bromochloro-5,5-dimethylhydantoin and 1,3-dichloro-5-ethyl-5-methyl hydantoin;alkali metal percarbonates such as sodium percarbonate, andalkali metal perborates such as sodium perborate(monohydrate and tetrahydrate). Preferred examples aresodium percarbonate and sodium perborate monohydrate.
• Preferably the solid phase comprises from 5 to 15wt%, morepreferably around 10wt% of an oxygen bleach such as alkalimetal perborate (by weight based on the total weight of thesolid phase), and from 1 to 10wt%, more preferably around6wt% of a bleach activator such as tetraacetylethylene-diamine(TAED). Most preferably the perborate and TAED aresegregated into different layers of the solid phase.
Fillers
• Typically, the solid phase of the block according to thepresent invention comprises up to 60% by weight of a filler.Preferred levels of filler range from 30 to 50wt% (by totalweight filler based on the total weight of the solid phase).
• Suitable fillers include urea, sodium, magnesium and calciumcarbonates, sodium chloride, borax, talc and sodium,magnesium and calcium sulphates.
• Preferably the solid phase comprises from 10 to 25wt% of asulphate filler, most preferably sodium sulphate (by weightbased on the total weight of the solid phase), and from 15to 35wt% of a carbonate filler, most preferably calciumcarbonate (by weight based on the total weight of the solidphase).
Whiteners and colouring agents
• Whiteners and/or colouring agents may be present in thesolid phase of the block according to the present invention,particularly when the solid phase has a multi-layeredstructure. If present, these materials should be chosen suchthat they are compatible with any bleaching agent present.Suitable colouring agents include Pigment Blue 15 (CI 74160)and Pyramid S Green ™, ex Minchem. Titanium dioxide is anacceptable whitener. Levels of whiteners and/or colouringagents are typically below 5wt% by total weight based on thetotal weight of the solid phase.
Complexing Agents
• The solid phase may usefully contain complexing agents forwater hardness and also for the heavy metal ions often encountered in water such as iron and manganese.
  Furthermore, the complexing agent may also improve thestability of any bleaching agent in the solid phase.
• Examples of suitable classes of complexing agents areaminopolycarboxylic acids, polyphosphonic acids and theirsalts, polymeric polycarboxylic acids and their salts, andhydroxypolycarboxylic acids and their salts. Preferred arepolyphosphonic acids and salts such as EDTMP (ethylenediamine tetra(methylene phosphonate)), Ca/Na salt.
• Preferably the solid phase comprises from 0.1 to 0.5wt%complexing agent (by weight based on the total weight of thesolid phase).
Optional ingredients
• The solid phase of the block according to the invention maycomprise a processing aid to assist in extrusion. Suitableprocessing aids include oils (including both mineral andsilicone oils), esters, alcohol ethoxylates, polybutene andmost preferably glycol ethers. The preferred level of glycolether is up to 4.5wt% (by weight based on the total weightof the solid phase). Furthermore the solid phase maycomprise a perfume wich may also partly or totally performthe function of processing aid.
Gel Phase
• The gel phase contains from 2 to 90% by weight of perfume(based on the total weight of the gel phase) and ispositioned in the recess of the solid phase, preferably byinjection.
• Preferably the gel phase contains 25-90%, more preferably40% to 70%, even more preferably 40-60% by weight perfume(based on the total weight of the gel phase).
• Suitable methods of forming the gel phase include heating,melting and mixing the perfume and gel together in avessel, or alternatively, heating and melting the gel in avessel, followed by adding the perfume to the melted geland then mixing.
• The perfume may be a single discrete ingredient, but moretypically will be a complex blend of volatile liquid (andsome solid) ingredients of natural and/or synthetic origin.
• Suitable gelling agents may be selected by those skilled inthe art, and include absorbents, starch based systems,modified celluloses, natural gums and other materials whichcan form a gel when mixed with the perfume.
• Preferred gelling agents are those which do not dissolve inwater.
• Further preferred gelling agents used to form the gel phasein the block according to the invention are polyamideresins. Particularly preferred are ester-terminatedpolyamide (ETPA) resins, such as are described in US5,783,657, and tertiary amide-terminated polyamide (ATPA)resins, such as are are described in US 6,268,466. Thesematerials create clear gels in a wide variety of solvents.
• Suitable resins are available commercially from ArizonaChemicals as UNICLEAR ™ and SYLVACLEAR ™ gellants.Particularly preferred are UNICLEAR ™ 100 and SYLVACLEAR ™A200.
• A preferred gel phase for use in the block according to theinvention may be prepared by warming the gelling agent,preferably a polyamide resin as described above, and theperfume with gentle mixing. At an elevated temperature,typically around 65 to 70 degrees C, the gelling agent andthe perfume form a solution or dispersion. The warm liquidmixture may be injected into the recess of the solid phaseof the block as described above.
• The gel phase may include other optional additives ascommonly used in the art, including solvents or carriers,inert additives such as pigmented or pearlescent particlesfor aesthetic purposes, or soluble additives such ascolourants. Solvents are not required to form the gel, butmay be used to dilute perfume ingredients to a suitableconcentration. Hydrophobic solvents are generally preferredfor this purpose and well known examples are C1-C4 estersof C8-C20 fatty acids.
• The gel phase of the blocks according to the invention ispreferably insoluble in water and thereby substantiallyretains its shape and size during the entire lifetime ofthe block.
Product Usage
• Blocks according to the invention are preferably arrangedin suitable holders such as cage or basket-like containerswhich can be suspended over the lavatory rim in such aposition that they can be reached by the flush water whichflows past whenever the lavatory is flushed. They arenormally suspended from the inner rim of the lavatory bowl,for example by a hook.
• The invention will now be illustrated by the following nonlimitingExample, in which all percentages are by weightbased on total weight, unless otherwise indicated.
EXAMPLE
• Lavatory blocks were prepared having a two-layer solidphase with ingredients as shown in the following Tables:

  Layer A
  INGREDIENT	LEVEL (wt% of total layer)
  Sodium ABS(1)	21.000
  Sodium PAS(2)	7.000
  Sodium Perborate Monohydrate	20.000
  EDTMP Ca/Na salt(3)	0.204
  Calcium Carbonate	19.850
  Sodium Sulphate	19.772
  Titanium Dioxide	1.000
  Colourant(4)	1.000
  Glycol Ether(5)	3.750
  Minors	to 100%

  Layer B
  INGREDIENT	LEVEL (wt% of total layer)
  Sodium ABS	21.000
  Sodium PAS	7.000
  TAED granules (83% a.i.)	12.450
  EDTMP Ca/Na salt	0.204
  Calcium Carbonate	23.000
  Sodium Sulphate	23.122
  Titanium Dioxide	0.500
  Glycol Ether	3.750
  Minors	to 100%

• The solid phase was formed by an extrusion process in whichthe ingredients of each layer were mixed and co-extruded asa plasticised mass through an extruder head so as to form acontinuous bar of the two layers A and B side-by-side. Theextruder head was shaped so as to produce a groove of 10 mmwidth extending along the entire length of one of the outerlongitudinal surfaces of the bar, and spanning the twolayers A and B.
• A gel phase was prepared by mixing 50wt% UNICLEAR™ 100, exArizona Chemical, 49.988wt% perfume (EMPTYSKY 375, ex IFF)and 0.012wt% dye (Sudan Blue, ex BASF) in a mixer heated bya heating jacket to 65 to 70 degrees C and equipped with apump and nozzle. The hot gel phase was dosed by pumping itthrough the nozzle so as to inject it into the recess ofthe solid phase which was mounted to run upon a beltconveyor into the path of the nozzle.
• After cooling, the gel-filled bar of solid phase soproduced was then cut into 48mm lengths to form the finallavatory blocks.
• The blocks were tested by placing in a cage suspended overthe rim of a lavatory which was contained in a boothmeasuring 4.35 cubic meters and which was flushed 15 timesa day. The perfume intensity of the blocks was evaluated ona scale of 1 to 10 by a panel of 20 subjects.
• The blocks of the invention gave improved perfumeperformance over 160 flushes compared to control blocks ofequivalent dimensions and solid phase composition, but inwhich the perfume was distributed throughout the blockrather than incorporated into a separate gel phase. Theimproved perfume performance of the blocks of the inventionwas observed even with lower overall levels of perfume thanin the control blocks (1g vs 1.6g), and was consistent overthe life of the block and also in between flushes.

Claims (12)

1. A lavatory cleansing and freshening block comprising asolid phase and a gel phase, in which the gel phasecontains from 2% to 90% by weight perfume (based on thetotal weight of the gel phase) and is positioned on thesurface of the solid phase.
2. A block according to claim 1, in which the solid phaseis in the form of one or more layers.
3. A block according to claim 1 or claim 2, in which thesolid phase comprises from 10 to 70wt% of surfactant (byweight based on the total weight of the solid phase).
4. A block according to any one of claims 1 to 3, in whichthe solid phase comprises from 5 to 15wt% of an alkali metalperborate (by weight based on the total weight of the solidphase), and from 1 to 10wt% a bleach activator (by weightbased on the total weight of the solid phase).
5. A block according to any one of claims 1 to 4, in whichthe solid phase comprises from 0.1 to 0.5wt% of a complexingagent (by weight based on the total weight of the solidphase).
6. A block according to any one of claims 1 to 5, in whichthe gel phase is formed from a polyamide resin.
7. A block according to claim 6, in which the polyamideresin is an ester-terminated polyamide (ETPA) resin or atertiary amide-terminated polyamide (ATPA) resin.
8. A block according to any one of claims 1 to 7, inwhich the gel phase contains from 40 to 60% by weightperfume (by weight based on the total weight of the gelphase).
9. A block according to any one of claims 1 to 8, inwhich the recess extends along the entire length of theouter longitudinal surface of the solid phase as a strip orgroove.
10. A process for producing a block according to any oneof claims 1 to 9, comprising the steps of:

    i) forming a solid phase by extruding a mixture of theconstituent ingredients

    ii) moulding a recess in an outer longitudinal surface ofthe solid phase

    iii) injecting a gel phase into the recess.
11. A process according to claim 10 comprising the stepsof:

    i) extruding the mixture of ingredients for the solidphase through a shaped extruder head which forms the recessin an outer longitudinal surface of the solid phase

    ii) mounting the extrudate so formed upon a belt conveyorwhich is arranged so that the gel phase may be injectedcontinuously into the recess of the solid phase as ittravels along the belt conveyor, and

    iii) cutting the gel-filled extrudate so formed into piecesof the desired size.
12. A process according to claims 10 or 11, in which theconstituent ingredients of the gel phase are heated, mixedand dosed through a nozzle into the recess in the solidphase.

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