EP1904618A1

EP1904618A1 - A packaged product for multi-phase laundry tablets

Info

Publication number: EP1904618A1
Application number: EP06818225A
Authority: EP
Inventors: Bas Jeroen Ten Brummelhuis; Pieter Everhardus Maria Overdevest; Peter Iwan Stuut
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2005-07-21
Filing date: 2006-07-11
Publication date: 2008-04-02
Also published as: GB0514951D0; WO2007025603A1

Abstract

A plurality of laundry tablets in combination with a packaging system, the system comprising an outer package having a base wall and a plurality of side walls and containing a plurality of inner packages in which the laundry tablets are arranged individually or in groups such that opposing diametrical faces of the tablets are substantially parallel to the longitudinal axis of the inner package; said laundry tablets having a plurality of discrete phases with differing compositions, wherein at least one first phase of the tablets is a smooth phase and at least one second phase of the tablets is a solid phase; and characterised in that the inner packages are arranged within the outer package such that the diametrical faces of the tablets lie in a plane generally orthogonal relative to the base wall.

Description

A PACKAGED PRODUCT FOR MULTI-PHASE LAUNDRY TABLETS

The present invention relates to multi -phase laundry tablets containing a smooth (or gel) phase and a solid phase, and a packaging system thereof .

Detergent compositions in tablet form have advantages over powdered products in that they do not require measuring and are thus easier to handle and dispense in the washload.

Tablets of a composition are generally made by compressing or compacting a quantity of the composition in particulate form.

Tablets comprising two or more separate regions have also been described. For example WO 01/42416 describes the production of multi-phase moulded bodies comprising a combination of core moulded bodies and a particulate premix. WO 00/61717 describes a detergent tablet which is characterised in that at least part of its outer surface is semi-solid. WO 00/04129 describes a multi-phase detergent tablet comprising a first phase in the form of a shaped body having at least one mould therein and a second phase in the form of a particulate solid compressed within said mould. WO 99/24549 describes a detergent tablet comprising a compressed solid body and a non-compressed gelatinous portion mounted in a mould of said body. WO99/27069 relates to a tablet comprising a compressed and a non-compressed phase, wherein the non-compressed phase improves stability of perfume components. There also have been prior publications on form stable, solid, and/or transparent smooth or gel-like detergent compositions. In GB 1578289 such a composition comprising soap, detergent and solvent has been proposed, for detergent sticks for use in wash or dry-cleaning pre-treatment .

Recently it has been suggested, for example in EP 1,371,729, EP 1,405,900, EP 1,382,368, EP 1,375,636, EP 1,405,901, EP 1,405,902, EP 1,418,224 and WO 03/104380 to prepare tablets comprising a smooth or semi-solid phase.

It is an object of the present invention to provide an improved multi-phase laundry tablet (s) and packaging therefor.

According to a first aspect of the invention, there is provided a plurality of laundry tablets in combination with an outer packaging system according to claim 1.

The "opposing diametrical faces" of the laundry tablets lie in parallel planes which are perpendicular to the longitudinal axis of the tablet. For example, in a cylindrical tablet the opposing diametrical faces correspond to the opposing circular upper and lower faces of the tablet.

The combination of a plurality of laundry tablets with the packaging system according to the invention prevents, or at least reduces, damage to the diametrical face of the smooth phase of a laundry tablet during packing, transportation and storage. It is essential to protect the smooth face of the laundry tablet as it is the part of the tablet most vulnerable to damage and yet it is the part of the tablet with greatest potential for visual appeal .

When a laundry tablet according to the invention is first produced, the diametrical face of the smooth phase is substantially flawless. It is essential to maintain this condition throughout packing, transportation and storage in order to protect increased aesthetic appeal of the smooth phase of the tablet .

Damage, such as indentation and possible break up of the smooth phase of the laundry tablet, results from the forces which act on the tablets within the outer package during packing, transportation and storage. For one laundry tablet these forces include, in a vertical direction, the effect of the weight of the tablets stacked above it (a major force for tablets toward the bottom of a stack) and also vertical impact forces, for example, when a transportation vehicle hits a speed ramp or a pot hole in the road. There may also be lateral impact forces, however, during transportation the total of both vertical forces can be greater than the lateral forces. Therefore, it is particularly desirable to protect the smooth face of the laundry tablet from the vertical forces.

In the packaging system of the present invention the diametrical faces of the smooth phase of the laundry tablets are protected from indentation or possible break up. This is because the diametrical face of the smooth phase is not exposed to the vertical forces which can cause significant damage to the smooth phase. By arranging the laundry tablets within the outer package such that their diametrical faces lie in a plane generally orthogonal relative to the base wall of the package, the surface of the smooth phase is protected. In this arrangement the vertical forces cannot compress the smooth face of the laundry tablet during transportation .

Thus the invention provides laundry tablets comprising a smooth phase such as, for example, a melt-casted, semi- solid, non-compressed or gel-like phase which exhibits improved aesthetic appearance as a result of the elimination, or at least reduction, of indentation. Furthermore, the efficiency of the smooth phase of the tablet to treat laundry is increased because the possibility of the smooth phase breaking up, spilling and adhering to the inner surface of the inner package is eliminated.

For the purpose of the present invention the term "generally orthogonal relative to the base wall" refers to the inner packages being generally upright. For example, in an outer package having a rectangular box construction with a flat base wall, the diametrical faces of the laundry tablets are generally aligned with the side walls of the pack.

It is anticipated that once the outer package is opened by the consumer and one or more of the inner packages have been removed for use, the remaining inner packages may no longer be substantially perpendicular to the base wall of the outer package. However, the object of the present invention is protection of the smooth phase of laundry tablets during packing, transportation and storage, prior to actual use of the product by the consumer. Once the package has been purchased, transported home and stored (for example, on a shelf or workspace) by the consumer the risk of the outer package experiencing any shocks is minimal. Therefore, the likelihood of damage to the smooth phase of the tablet is very low after opening of the package.

Preferably the solid phase of the laundry tablets has a diametrical fracture stress of 10-4OkPa. It is advantageous for the solid phase of the tablet to have a low diametrical fracture stress in order for the tablet to exhibit improved dissolution properties. The diametrical fracture stress of the tablet is linked to the compression stress used to form the tablet. By selecting a lower diametrical stress, a lower compression stress is required, making the tablet less dense and therefore exhibiting better dispersion and dissolution properties.

However, one problem with tablets having a lower diametrical fracture stress is that they exhibit mechanical fragility and therefore have an increased tendency to break up during transit/handling .

The present invention enables the solid phase of the laundry tablets to have a lower diametrical fracture stress because the diametrical face the solid phase is protected by the packaging system employed. This is because when the diametrical faces of the laundry tablets lie in a plane generally orthogonal to the base wall of the outer package, the diametrical face of the solid phase is not subjected to damaging vertical impact forces during packing, transportation and storage and therefore, the likelihood of the solid phase breaking up is significantly reduced.

The Outer Package

The outer package may be a rectangular box construction comprising a flat base wall and four side walls together defining a storage space for storing the inner packages containing the laundry tablets.

The outer package may further comprise a lid portion comprising a top wall opposed to the base wall . Preferably the lid portion is hingedly connected to one or more of the side walls and further comprises one or more lid flaps depending from the top wall. The lid portion may be closable to overlie the storage space such that the one or more lid flaps overlie an upper portion of the respective side walls.

In one embodiment the outer package may comprises one or more reclosable locking means in the form of a "snap-lock" mechanism. Such a "snap-lock" mechanism may comprise one ore more locking flaps, extending from the centre of the top edge of the same side wall as that which the lid flap(s) overlies and along a substantial distance of its length. The locking means may comprise a locking portion and a lid attachment portion attached to the inner surface of the respective lid flap.

The outer package may be formed from any suitable packaging materials including plastic, paperboard, cardboard or mixtures thereof. Preferably the outer package is formed from corrugated cardboard with layers of plastic materials for barrier purposes.

In a preferred embodiment the outer surface of the outer package comprises visual indicia which indicates to the person stacking the outer packages onto a shelf in a shopping outlet, such as a supermarket, which side of the package is the base. Therefore, the outer packages will not be stacked such that the diametrical face of the smooth phase of the laundry tablets is subject to the damaging vertical forces during display.

The Inner Package

The inner package may be rigid or flexible.

The inner package may comprise one or more seals which may be sealed using an adhesive. Preferably, the inner package is a film package such as a flow pack, comprising a tubular film bag with one longitudinal seam and two transverse seams at opposing ends of the tubular bag.

Preferably the film has an moisture vapour transfer rate of 1-20 g/m²/day and more preferably 1-10 g/m²/day in order to protect the laundry tablet (s) .

In a preferred embodiment the inner package may comprises an inner surface, at one region of which bears an adhesive.

Preferably the adhesive is located on a region or regions of the inner surface of the package adjacent the solid phase of the laundry tablet (s) . This enable the adhesive to pick up any loose particulate matter which has broken away from the solid phase before it reaches the smooth phase. Therefore, there is no dulling in the shininess or translucency of the smooth phase and its visual appearance is maintained. Most preferably the region (s) of adhesive bounds at least one side of the longitudinal seal of the inner package.

The transverse seals of the inner package, when arranged within the outer package according to the packaging system of the present invention, may act as cushioning means for the respective lateral face of the laundry tablet (s) contained therein. The transverse seals absorb shock as a result of vertical impact forces and, therefore, prevent, or at least reduce, damage to the lateral faces of the tablets.

Preferably the laundry tablets are packaged individually or in groups corresponding to a unit dose within the inner package .

The laundry tablets may be arranged in pairs and are preferably side-by-side within the inner package such that the lateral faces of the tablets are adjacent. This is advantageous because the diametrical face of the smooth phase of the laundry tablets are prevented from directly contacting the diametrical face of the solid phase.

Preferably the diametrical face of the solid phase of the tablets are adjacent the longitudinal seal of the inner package . Preferably the laundry tablet of the invention cleans, softens and/or freshens the laundry fabrics being treated in the washing machine. Most preferably it is a laundry cleaning tablet capable of cleaning the laundry fabrics.

The regions of the tablet are preferably separate layers within a cleaning tablet. However, a discrete region of a tablet could also have other forms for example one or more core(s) or insert (s) . Preferably, a "phase" is a discrete region at the tablet having a particular composition and/or physical nature such as morphology, texture or appearance.

The tablets utilised in the present invention may be any suitable shape, e.g. spherical or polyhedral (which maybe square or rectangular in cross section. However, preferably they are of cylindrical shape wherein the two main surfaces (upper side and lower side) are substantially flat. In one embodiment, the outer surface of the smooth phase is dome- shaped to facilitate pre-treatment application.

The multi -phase tablets used in the present invention comprise at least one smooth phase and at least one solid phase. It may also comprise at least one intermediate phase if the smooth phase comprises a relatively high level of liquid component so as to improve the stability of the tablet during storage.

The First Smooth Phase

For the purpose of this invention the term "smooth phase" refers to compositions which are on the one hand solid enough to retain their shape at ambient temperature and on the other hand smooth in appearance. Smooth textures are generally of low or no porosity and have, at normal viewing distance, the appearance of a continuous phase for example as opposed to porous and particulate appearance of a compacted particulate material .

Preferably the smooth phase is transparent or translucent.

Preferably the smooth phase of the tablet is a semi-solid phase. For the purpose of this invention the term semi-solid refers to compositions which are on the one hand solid enough to retain their shape at ambient temperature but which are neither completely solid. A suitable test to check if a composition can be considered as a semi-solid is, for example, described in EP 1,375,636.

The other phases of the laundry tablet are possibly separate layers within the tablet, preferably substantially flat layers. Preferably the smooth phase covers a substantial part of the upper surface of the other phase, e.g. preferably at least 65%, more preferred at least 75%, most preferred more than 90% or even substantially all of the upper surface of the other phase is covered by the first smooth phase. For the purpose of the invention the term upper surface refers to one of the main sides of the laundry tablet which by placing the tablet on a flat surface could be classified as the upper surface. Especially preferably the other phase of the tablet suitably is a layer of compacted particulate material, preferably having a substantially flat upper surface. In one embodiment the diametrical face of the smooth phase may comprise an embossed design. For example, it may comprise from 5 to 25 rounded ridges so as to improve the dissolution rate of the smooth phase of the tablet and reduce contact between the user and the smooth phase . Alternatively the outer surface of the smooth phase may comprise a raised trademark design. Such embossed designs present on the smooth phase of the tablet are protected by the packaging system of the present invention because they will not be subject to the damaging vertical compression forces during packing, transportation and storage.

Preferably the first smooth phase is a layer having an average thickness of from 0.5 to 10 mm, more preferred 1 to 6 mm, for example 1.5 to 5 mm. Preferably the total weight the smooth phase is from 1 to 40 grammes, more preferred from 3 to 30 grammes, most preferred from 4 to 10 grammes, preferably the level of non-soap surfactants in the smooth phase is from 0.5 to 10 grams, more preferred from 1 to 7 grams .

In an advantageous embodiment of the invention the smooth or semi-solid first phase comprises from 40-100 wt% of non-soap surfactants (based on the total weight of the smooth phase) , more preferred from 50-95 wt%, most preferred the first phase is predominantly constituted by non-soap surfactants e.g. more than 60 wt% for example 70 to 90 wt%. It has been found that the combination of a separate smooth or semisolid phase and these high surfactant levels provide very good dispersing and cleaning properties to the tablet. Also advantageously the smooth or semi-solid phase may comprise soap for example at a level of 0.1 to 10 wt% based on the weight of the smooth or semi-solid part. Especially preferably the soap is present in a level of at least 1 wt% of the smooth phase. In a very preferred embodiment of the invention the level of C16 soaps is relatively high, particularly it is preferred that at least 50 wt% of the soap is a C16 soap, even more preferred from 60 to 100 wt% of the soap is a C16 soap.

Also advantageously the first smooth phase of the tablet comprises at least 5 wt% of diluent materials having a dielectric constant of from 5 to 16. Also preferably the molecular weight of the diluents is from 50 to 250, e.g. from 100 to 200. Preferred examples of diluents are for example, Tri-ethyleneglycol di -methyl ether or Di- (Ethylene Glycol) Ethyl ether or mixtures thereof. Preferably the level of the diluents is from 5 to 40 wt%, more preferred 2 to 30, most preferred 10-25 wt% based on the weight of the smooth phase. Also preferably the diluents used in the smooth phase preferably have a flashpoint of at least 75⁰C, most preferred above 80⁰C or even above 90 ⁰C.

The smooth or semi-solid phase preferably comprises no or only low levels of water. Preferably the level of water is less than 20 wt % based on the weight of the semi-solid phase, more preferred less than 15 wt%, most preferred from 5 to 12 wt%. Most preferably the smooth or semi-solid phases are substantially free from water, which means that apart from low levels of moisture (e.g. for neutralisation or as crystal water) no additional added water is present. The smooth phase may be prepared by heating the ingredients together until they melt to form a substantially homogeneous liquid, followed by cooling to solidification and if necessary, cutting or otherwise forming to the desired shape and size.

The Second Solid Phase

The lower diametrical fracture stress of the second solid phase means that the level of dispersion aids can be set more freely, leaving room within the tablet formulation for increased levels of other active agents.

Preferably, the diametrical fracture stress is 10-3OkPa.

Because the tablet is not as dense and more prone to breaking up during filling, the amount of disintegrating agents such as water swellable polymers can be reduced. The amount of such polymers, such as sodium carboxymethyl cellulose SCMC, is preferably less than 0.5% and even more preferably less than 0.1% and more preferably 0%.

Similarly the level of disintegrants may be less than 5%, preferably less than 0.5%, more preferably less than 0.1% and even more preferably 0%.

It is preferred to use a tablet having less than 45% by weight of phosphate or poly-phosphate compounds, more preferably less than 30% even more preferably less than 15 and most preferably 0% of phosphate or poly-phosphate compounds. Reducing the level of phosphate or polyphosphate makes the tablet more environmentally acceptable.

Dispersants may be provided in the form of disintegrating- promoting particles. Such particles typically contain at least 40% (of their own weight) of one or more:

• compounds with a water-solubility exceeding 50 grams per 100 grams water

• water swellable materials such as for example cellulose, cross-linked polyethylene glycol, cross linked polyvinyl pyrrolidone or an acrylic/maleic copolymer

• phase I sodium tripolyphosphate

• sodium tripolyphosphate which is partially hydrated so as to contain water of hydration in an amount which is at least 0.5% by weight of the sodium tripolyphosphate in the particles .

The total quantity of disintegration-promoting particles may be less than 5%wt and preferably less than 1% and more preferably 0% of the tablet.

The weight of the solid phase may suitably range from 1 to 60 grams, more preferred from 10 to 50 grams, most suitably from 20 to 40 grams.

The second phase may comprise no or only low levels of surfactants. Preferably the level of surfactants in the second phase is less than 10 wt% (based on the total weight of the second phase) , more preferred from 0 to 9 wt%, most preferred from 1 to 8 wt%. The second phase preferably comprises ingredients of the cablet other than surfactants. Examples of these ingredients are builders, bleach system, enzymes etc. Preferably the builders in the tablet are predominantly present in the second phase. Preferably the bleach system is predominantly present in the second phase. Preferably the enzymes are predominantly present in the second phase. For the purpose of this invention the term "predominantly present" refers to a situation wherein at least 90 wt% of an ingredient is present in the second phase, more preferred more than 98 wt%, most preferred substantially 100 wt%. Materials which may be used in tablets of this invention will now be discussed in more detail.

Surfactant Compounds

Compositions which are used in tablets of the invention will contain one or more detergent surfactants. In a laundry tablet composition, these preferably provide from 5 to 50% by weight of the overall tablet composition, more preferably from 8 or 9% by weight of the overall composition up to 40% or 50% by weight. Surfactant may be anionic (soap or non- soap) , cationic, zwitterionic, amphoteric, nonionic or a combination of these.

Anionic surfactant may be present in an amount from 0.5 to 50% by weight, preferably from 2% or 4% up to 30% or 40% by weight of the tablet composition.

Synthetic (i.e. non-soap) anionic surfactants are well known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly sodium linear alkylbenzene sulphonates having an alkyl chain length of C₈-Ci₅; olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates ; and fatty acid ester sulphonates.

Primary alkyl sulphate having the formula

ROSO₃ ^" M⁺

in which R is an alkyl or alkenyl chain of 8 to 18 carbon atoms especially 10 to 14 carbon atoms and M⁺ is a solubilising cation, is commercially significant as an anionic surfactant . Linear alkyl benzene sulphonate of the formula

where R is linear alkyl of 8 to 15 carbon atoms and M⁺ is a solubilising cation, especially sodium, is also a commercially significant anionic surfactant.

Frequently, such linear alkyl benzene sulphonate or primary alkyl sulphate of the formula above, or a mixture thereof will be the desired anionic surfactant and may provide 75 to 100 wt% of any anionic non-soap surfactant in the composition. In some forms of this invention the amount of non-soap anionic surfactant lies in a range from 5 to 20 wt% of the tablet composition.

Soaps for use in accordance to the invention are preferably sodium soaps derived from naturally occurring fatty acids, for example, the fatty acids from beef tallow.

Suitable nonionic surfactant compounds which may be used include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide.

Specific nonionic surfactant compounds are alkyl (C_8-22) phenol -ethylene oxide condensates, the condensation products of linear or branched aliphatic C_8-2O primary or secondary alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylene-diamine.

Especially preferred are the primary and secondary alcohol ethoxylates, especially the C₉-n and C₁₂-₁₅ primary and secondary alcohols ethoxylated with an average of from 5 to 20 moles of ethylene oxide per mole of alcohol.

In some laundry tablets of this invention, the amount of nonionic surfactant lies in a range from 4 to 40%, better 4 or 5 to 30% by weight of the whole tablet. Many nonionic surfactants are liquids. These may be absorbed onto particles of the composition.

Detergency Builder

A composition which is used in tablets of the invention will usually contain from 5 to 80%, more usually 15 to 60% by weight of detergency builder. This may be provided wholly by water soluble materials, or may be provided in large part or even entirely by water-insoluble material with water- softening properties. Water-insoluble detergency builder may be present as 5 to 80 wt%, better 5 to 60 wt% of the composition.

Alkali metal aluminosilicates are strongly favoured as environmentally acceptable water- insoluble builders for fabric washing. Alkali metal (preferably sodium) aluminosilicates may be either crystalline or amorphous or mixtures thereof, having the general formula:

0.8 - 1.5 Na₂O-Al₂O₃. 0.8 - 6 SiO₂. XH₂O

These materials contain some bound water (indicated as DxH2O≤) and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g . The preferred sodium aluminosilicates contain 1.5-3.5 SiO₂ units (in the formula above) . Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1429143 (Procter & Gamble) . The preferred sodium aluminosilicates of this type are the well known commercially available zeolites A and X, the novel zeolite P described and claimed in EP 384070 (Unilever) and mixtures thereof .

Conceivably a water-insoluble detergency builder could be a layered sodium silicate as described in US 4664839.

NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly abbreviated as DSKS-β"). NaSKS-6 has the delta-Na₂Si0₅ morphology form of layered silicate. It can be prepared by methods such as described in DE-A-3,417,649 and DE-A-3 , 742 , 043. Other such layered silicates, such as those having the general formula NaMSi_xO_2x+I .yH₂O wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20, preferably 0 can be used.

Water-soluble phosphorous-containing inorganic detergency builders, include the alkali-metal orthophosphates, metaphosphates, pyrophosphates and polyphosphates. Specific examples of inorganic phosphate builders include sodium and potassium tripolyphosphates, orthophosphates and hexametaphosphates .

Non-phosphorous water-soluble builders may be organic or inorganic. Inorganic builders that may be present include alkali metal (generally sodium) carbonate; while organic builders include polycarboxylate polymers, such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphonates, monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono- di- and trisuccinates , carboxymethyloxysuccinates , carboxymethyloxymalonates, dipicolinates and hydroxyethyliminodiacetates .

At least one phase (preferably the second phase) of a laundry tablet preferably include polycarboxylate polymers, more especially polyacrylates and acrylic/maleic copolymers which can function as builders and also inhibit unwanted deposition onto laundry fabric from the wash liquor.

Bleach System

Tablets according to the invention may contain a bleach system in at least one phase of a tablet, preferably in the second phase. This preferably comprises one or more peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, which may be employed in conjunction with activators to improve bleaching action at low wash temperatures. If any peroxygen compound is present, the amount is likely to lie in a range from 10 to 25% by weight of the composition.

Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate, advantageously employed together with an activator. Bleach activators, also referred to as bleach precursors, have been widely disclosed in the art. Preferred examples include peracetic acid precursors, for example, tetraacetylethylene diamine (TAED) , now in widespread commercial use in conjunction with sodium perborate; and perbenzoic acid precursors . The quaternary ammonium and phosphonium bleach activators disclosed in US 4751015 and US 4818426 (Lever Brothers Company) are also of interest. Another type of bleach activator which may be used, but which is not a bleach precursor, is a transition metal catalyst as disclosed in EP-A-458397, EP-A-458398 and EP-A-549272. A bleach system may also include a bleach stabiliser (heavy metal sequestrant) such as ethylenediamine tetramethylene phosphonate and diethylenetriamine pentamethylene phosphonate .

As indicated above, if a bleach is present and is a water- soluble inorganic peroxygen bleach, the amount may well be from 10% to 25% by weight of the composition.

Other Detergent Ingredients

The laundry tablets of the invention may also contain (preferably in the second phase) one of the detergency enzymes well known in the art for their ability to degrade and aid in the removal of various soils and stains. Suitable enzymes include the various proteases, cellulases, lipases, amylases, and mixtures thereof, which are designed to remove a variety of soils and stains from fabrics. Examples of suitable proteases are Maxatase (Trade Mark) , as supplied by Gist-Brocades N. V. , Delft, Holland, and Alcalase (Trade Mark) , and Savinase (Trade Mark) , as supplied by Novo Industri A/S, Copenhagen, Denmark. Detergency enzymes are commonly employed in the form of granules or marumes, optionally with a protective coating, in amount of from about 0.1% to about 3.0% by weight of the composition; and these granules or marumes present no problems with respect to compaction to form a tablet.

The laundry tablets of the invention may also contain (preferably in the second phase) a fluorescer (optical brightener) , for example, Tinopal (Trade Mark) DMS or Tinopal CBS available from Ciba-Geigy AG, Basel, Switzerland. Tinopal DMS is disodium 4 , 4 'bis- (2 -morpholino- 4-anilino-s-triazin-6-ylamino) stilbene disulphonate,- and Tinopal CBS is disodium 2 , 2 ' -bis- (phenyl -styryl) disulphonate. An antifoam material is advantageously included (preferably in the second phase) , especially if a laundry tablet is primarily intended for use in front-loading drum-type automatic washing machines. Suitable antifoam materials are usually in granular form, such as those described in EP 266863A (Unilever) . Such antifoam granules typically comprise a mixture of silicone oil, petroleum jelly, hydrophobic silica and alkyl phosphate as antifoam active material, absorbed onto a porous absorbed water-soluble carbonate-based inorganic carrier material. Antifoam granules may be present in an amount up to 5% by weight of the composition.

It may also be desirable that a laundry tablet of the invention includes an amount of an alkali metal silicate, particularly sodium ortho-, meta- or disilicate. The presence of such alkali metal silicates at levels, for example, of 0.1 to 10 wt%, may be advantageous in providing protection against the corrosion of metal parts in washing machines, besides providing some measure of building and giving processing benefits in manufacture of the particulate material which is compacted into tablets.

A tablet for fabric washing will generally not contain more than 15 wt% silicate. Preferably the silicate is present in the second phase of the tablet .

Further ingredients which can optionally be employed in a phase of a laundry tablet of the invention (preferably the second phase) include anti-redeposition agents such as sodium carboxymethylcellulose, straight -chain polyvinyl pyrrolidone and the cellulose ethers such as methyl cellulose and ethyl hydroxyethyl cellulose, fabric-softening agents; heavy metal sequestrants such as EDTA; perfumes; and colorants or coloured speckles.

Further ingredients which can optionally be used in tablets of the invention, preferably in the second phase are dispersing aids. Examples of suitable dispersing aids are water-swellable polymers (e.g. SCMC) highly soluble materials (e.g. sodium citrate, potassium carbonate or sodium acetate) or sodium tripolyphospate with preferably at least 40% of the anhydrous phase I form.

Particle Size and Distribution

The second phase of laundry tablet of this invention, is a preferably a matrix of compacted particles. Preferably the particulate composition has an average particle size in the range from 200 to 2000 μm, more preferably from 250 to 1400 μm. Fine particles, smaller than 180 μm or 200 μm may be eliminated by sieving before tableting, if desired, although we have observed that this is not always essential.

While the starting particulate composition may in principle have any bulk density, the present invention is especially relevant to tablets made by compacting powders of relatively high bulk density, because of their greater tendency to exhibit disintegration and dispersion problems. Such tablets have the advantage that, as compared with a tablet derived from a low bulk density powder, a given dose of composition can be presented as a smaller tablet .

Thus the starting particulate composition may suitably have a bulk density of at least 400 g/litre, preferably at least 500 g/litre, and perhaps at least 600 g/litre.

Tableting machinery able to carry out the manufacture of tablets of the invention is known, for example suitable tablet presses are available from Fette and from Korch.

Tableting may be carried out at ambient temperature or at a temperature above ambient which may allow adequate strength to be achieved with less applied pressure during compaction. In order to carry out the tableting at a temperature which is above ambient, the particulate composition is preferably supplied to the tableting machinery at an elevated temperature. This will of course supply heat to the tableting machinery, but the machinery may be heated in some other way also.

The size of a tablet will suitably range from 10 to 160 grams, preferably from 15 to 60 g, depending on the conditions of intended use, and whether it represents a dose for an average load in a fabric washing or dishwashing machine or a fractional part of such a dose. The tablets may be of any shape. However, for ease of packaging they are preferably blocks of substantially uniform cross-section, such as cylinders or cuboids. The overall density of a tablet preferably lies in a range from 1040 or 1050gm/litre up to 1600gm/litre.

The above description of the tablet has been given with reference to a tablet constituted by one or two phases. It will however be understood that each of the phase may be composed of a limited number of discrete regions.

Laundry tablets of the invention may be manufactured by any suitable method e.g. the pre-preparation of the smooth phase e.g. by extrusion or melt -casting followed by assembly of the smooth phase and the other phases of the tablet. Also the second phase of compressed particulate material may be pre-prepared followed by in-situ preparation of the smooth phase e.g. by casting, coating or spraying, or assembly of said compressed phase with a separately prepared smooth phase. Typical processing conditions for preparing the smooth phase or the compressed phase are for example disclosed in the documents as described above. The invention will be more clearly understood from the following description of some of the embodiments thereof, given by way of example only, with reference to the accompanying drawings in which: -

Figure 1 is a perspective view of an outer package containing a plurality of inner packages according to the packaging system of the invention, following opening of the outer package; and

Figure 2 is a perspective view of an inner package according to the present invention.

Referring to figure 1 an outer package comprising a carton, generally indicated at 100 is shown. The outer package 100 houses a plurality of inner packages 200 (only one row shown) containing laundry tablets 300 corresponding to a unit dose. The outer package 100 comprises a base wall 107, opposing side walls 109,111 and opposing front wall 101 and rear wall 105 together defining a storage space 113 for storing a plurality of inner packages 200.

The outer package 100 further comprises a lid 115 which is hingedly connected to the rear wall 105 and comprises a top wall 103 opposed to the base wall 107, and a front lid flap 117 depending from the top wall 103. The lid 115 is closable to overlie the storage space 113 such that the lid flap 117 overlies an upper portion of the front wall 101. The lid flap 117 has lines of weakness comprising perforations and defining respective ears 119,121. The outer package 100 is formed from corrugated cardboard and is sized such that it houses 12 inner packages 200.

Referring to fig 2, there is illustrated a flow wrap inner package 200 containing a pair of laundry tablets 300.

The flow wrap inner package 200 comprises a tubular plastic film bag having a longitudinal seal 201 and two transverse end seals 203.

The longitudinal seal 201 is bounded on both sides by- longitudinal strips of adhesive (not shown) .

The laundry tablets 300 comprise two discrete phases, a smooth phase 301 comprising a translucent gel and a solid phase 303 comprising compacted particulate material.

The laundry tablets 300 are oriented within the inner package 200 such that the diametrical faces 305 of the smooth and solid phases (diametrical face of the solid phase not shown) of the tablets are substantially parallel to the longitudinal seal 201 of the inner package 200. Furthermore, the solid phase of the tablet 303 is adjacent/contiguous the longitudinal seal 201 of the inner package 200 and the strips of adhesive.

The adhesive is used in the formation of the flow-wrap. In this way an extra adhesive apply step is not necessary in the flow-wrap manufacturing process. This process essentially comprises the formation of a film tube from a strip of plastic film which is wrapped and sealed longitudinally. The tube is then sequentially filled (with the laundry tablets 300) transversely sealed and cut to provide individual inner packages 200.

The longitudinal seal 201 is formed using a pressure sensitive adhesive applied in a wide band longitudinally of the film strip.

The adhesive band is wide enough such that after the longitudinal (fin) seal 201 is formed the seal 201 is bordered on each side by adhesive .

The transverse seals on also formed by adhesive.

In an alternative embodiment the package seals could be formed by heat sealing and the adhesive applied prior to the sealing process.

There may be a combination of heat/adhesive sealing e.g. longitudinal adhesive sealing and transverse heat sealing.

The inner packages 200 are arranged within the outer package 100 such that the diametrical faces of the tablets 300 lie in a plane generally orthogonal relative to the base wall 107 of the outer package 100.

An exemplary laundry tablet formulation is as follows:

A detergent powder was made of the following composition: A detergent base powder, incorporating organic surfactants, a small percentage of crystalline sodium acetate trihydrate, and zeolite MAP was made using known granulation technology. It had the following composition, shown as parts by weight.

The amount of zeolite MAP (zeolite A24) in the table above is the amount which would be present if it was anhydrous. Its accompanying small content of moisture is included as part of the moisture and minor ingredients. The base powder and other ingredients were mixed together as set out in the following table. Comp A.

Base powder, as above 57.18

Antifoam (1) 2.30 Fluorescer (2) 1.59

Sodium percarbonate 19.23

TAED (3 ) 6.48

Sodium disilicate 4.07

Soil release polymer (4) 1.40 Acrylic/maleic copolymer (5) 1.53

EDTM phosphonate 0.95 Colored speckles 1.77 Cellulosic swelling disintegrant (6) 3.50 Total 100

Wherein: (1) Antifoam is 17%wt silicon oil, 71%wt sodium carbonate and the remainder petroleum jelly and phosphate ester.

(2) Fluorescer is 9.9%wt Fluorescer and 82.5%wt sodium carbonate the remainder being minor ingredients

(3) TAED is 83%wt TAED in 9%wt sodium sulphate the remainder being minor ingredients.

(4) Soil release polymer is 18%wt soil-release polymer, 44%wt zeolite MAP,

21%wt sodium carbonate and minor ingredients.

(5) Acrylic/maleic polymer is Sokolan CP5 ex BASE (91%wt active) (6) Cellulosic swelling disintegrant (Arbocel ex

Rettenmaier) The solid phase was made by mixing the ingredients (except for the cellulosic swelling disintegrant ) and finally adding the cellulosic swelling disintegrant.

The solid phase was made in a labscale Graseby Specac tabletting press; and had a strength (expressed in terms of the diametrical fracture stress) of approximately 25k Pa. The diametrical stress is defined as DFS=2*Fmax/ ( π*D*t) with Fmax being the tablet strength expressed as the force required to break a tablet when it is applied on its circumference. D the tablet diameter and t its thickness.

A second exemplary solid phase formulation is exactly as for the above formulation an except that the level of the cellulosic swelling disintegrant is to 1.75% wt (and the base powder increased to 58.93% wt of the final formulation.

Smooth or semi-solid parts were prepared of the following composition:

Notes: * is a C16-C18 soap

The mixture semi solid part composition was heated to 80⁰C and cast into moulds and cooled to 20⁰C to form firm, 5 grammes smooth and semi-solid parts of 32mm diameter and 6mm high.

Multi-layer tablets are made by pre-compressing 25 grammes of the powdered composition in a die of 45 mm diameter at 4 kN/cm² , followed by adherence of a smooth and semi-solid part on top of the compressed layer followed by a final compression step at 0.1 kN/cm². During the final compression step, the smooth and semi-solid part flows by the compaction forces to form a 3.4 mm smooth semi-solid layer adhered on top of the compressed particulate layer.

After the final compression step the diametrical fracture stress of the second solid phase is still less than 3OkPa.

In use, the outer package 100 containing a plurality of inner packages 200 is first opened by grasping the lid flap 117 and lifting upwards ripping the lines of weakness to release lid 115 leaving small ears 119 and 121 in place attached to the front wall 101.

An inner package 200 containing the laundry tablets 300 corresponding to a unit dose is removed from the outer package 100 via the transverse end seal 203 exposed upon opening of the outer package 100. The inner package 200 is then torn open and the laundry tablets 300 are dropped into the washing machine.

Alternatively, the laundry tablets 300 are placed in a dispensing device, such as a net bag, and then placed in the washing machine . The above embodiments of the present invention have been described by way of example only and various alternative features or modifications from what has been specifically described and illustrated can be made within the scope of the invention, as will be readily apparent to persons skilled in the art.

Claims

1. A plurality of laundry tablets in combination with a packaging system, the system comprising an outer package having a base wall and a plurality of side walls and containing a plurality of inner packages in which the laundry tablets are arranged individually or in groups such that opposing diametrical faces of the tablets are substantially parallel to the longitudinal axis of the inner package; said laundry tablets having a plurality of discrete phases with differing compositions, wherein at least one first phase of the tablets is a smooth phase and at least one second phase of the tablets is a solid phase; and characterised in that the inner packages are arranged within the outer package such that the diametrical faces of the tablets lie in a plane generally orthogonal relative to the base wall.

2. A combination according to claim 1, wherein the laundry tablets are packaged individually or in groups corresponding with a unit dose within the inner package.

3. A combination according to claim 1 or 2, wherein the laundry tablets are arranged within the inner package such that the lateral faces of the tablets are adjacent.

4. A combination according to any preceding claim, wherein the first phase of the tablet is a smooth or semi-solid layer and the second phase of the tablet is a layer of compacted particulate material.

5. A combination according to any preceding claim, wherein the solid phase of the laundry tablet has a diametrical fracture stress of 10-4OkPa.

6. A combination according to any preceding claim, wherein the laundry tablet cleans, softens or freshens the laundry fabrics .

7. A combination according to any preceding claim, wherein the diametrical face of the smooth phase of the laundry tablet comprises an embossed design.

8. A combination according to claim 1, wherein the inner package comprises a film package having one longitudinal seal and two transverse end seals.

9. A combination according to claim 8, wherein the inner package comprises an inner surface, at least one region of which bears an adhesive.

10. A combination according to claim 8 or 9, wherein the transverse end seals function as shock absorbing means.

11. A combination according to claim 1, wherein the outer surface of the outer package comprises visual indicia identifying the base wall of the package.