EP1601754B1

EP1601754B1 - A water soluble delivery product

Info

Publication number: EP1601754B1
Application number: EP04709220A
Authority: EP
Inventors: Cornelis B. Unilever R & D Vlaardingen DONKER; Vidyadhar S. Unilever R & D Vlaardingen RANADE; H. A. H. M. Unilever R & D Vlaardingen REBERS
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2003-03-12
Filing date: 2004-02-09
Publication date: 2007-05-16
Anticipated expiration: 2024-02-09
Also published as: ATE362522T1; ES2286606T3; DE602004006497D1; DE602004006497T2; GB0305666D0; EP1601754A1; WO2004081162A1

Abstract

A delivery product for delivery of a predetermined amount of first and second fluids, the product comprising an outer water soluble capsule containing a first fluid substance for release on dissolution of the outer capsule and an inner capsule containing a second fluid substance for release on dissolution of the inner capsule, wherein the inner capsule is substantially spherical.

Description

The invention relates to a water soluble delivery product comprising outer and inner water soluble capsules containing respective first and second fluid substances for release on dissolution of the capsules.
Detergent compositions for machine washing of laundry and dishes, crockery etc are provided in many forms such as free-flowing powders, liquids, etc.. Detergents in the form of compressed powder tablets are also commonly available. These are advantageous in that they do not require measuring they are thus easier to handle and dispense into the wash load and allow for accurate dosing in detergent.
More recently water-soluble capsules of detergent composition in liquid and other forms have been introduced. Water-soluble capsules generally comprise a detergent composition encapsulated with water-soluble film, such as polyvinyl alcohol. Encapsulation allows for handling of the product without direct contact with the detergent composition. This is especially advantageous when the detergent composition includes aggressive cleaning components which would irritate the skin on direct contact.
It may be desirable for performance and/or aesthetic reasons to separate certain ingredients. Various solutions to this problem have been proposed e.g. a multi-compartment pouch as in EP253566 or a pouch within a pouch as in US 4082678 and in US 6 448 212. However, a possible problem with capsules containing inner capsules is the physical interaction of the two capsules.
There is also a need to provide a dual compartment capsule which reduces film usage.
According to the invention, there is provided a delivery product for delivery of a predetermined amount of first and second fluids, the product comprising an outer water soluble capsule containing a first fluid substance for release on dissolution of the outer capsule and an inner capsule containing a second fluid substance for release on dissolution of the inner capsule; wherein the inner capsule is spherical.
The provision of a spherical inner capsule has many advantages. The spherical shape which offers minimal/no pointed portions, serves to reduce abrasion of the outer capsule as the inner capsules rubs against it, e.g. during packing, transportation or handling by the user. Advantageously, the inner capsule preferably has minimal or preferably no external seals which could otherwise increase interference between the capsule during packing, transportation or handling and so lead to leakage.
The provision of a spherical inner capsule also provides a high volume to surface area ratio, which reduces the usage of capsule material and reduces after-use residues because of low seal area.
Preferably the outer capsule has a dome shaped body portion for containing the substance comprising a first sheet of a water soluble material thermoformed to form a body wall of the body portion, and a second sheet of water soluble material superposed on the first sheet and sealed thereto along a continuous region of the superposed sheets to form a base wall of the body portion. This formation provides for a more robust outer capsule, and reduction in leaking.
As used herein, the term "sheet" is intended to include both monolayer or multilayer constructions; the term "fluid is intended to include any flowable material, e.g. any particulate matter (powders,agglomerates), liquid, gel,paste and the like; "substantially spherical" is intended to also include asymmetrical shaped capsules with slightly elliptical formations as well as symmetrical regular spheres.
Advantageously, in addition to a spherical inner capsule, the outer capsule may also have a gas entrapped within it. The volume of gas bubble(s) in the outer capsule could be from 5-35% of the total volume of outer capsule. This air bubble serves as a cushion for the inner capsule in that it reduces compression forces that are transmitted to the inner capsule from the outer capsule. In a preferred embodiment the entrapped gas is air.
The dome shaped outer capsule is preferably substantially spherical in shape. The combination of thermoforming the capsules of the invention and forming the capsules into a substantially spherical dome shape together with the provision of a spherical inner capsule confers surprising advantages on the capsules of the invention.
A substantially spherical dome offers sufficient width within the dome to put a spherical inner capsule in it as compared to say a rectangular dome having same volume as the said spherical dome. Also, since the average distance of walls of outer dome to walls of inner capsule is less for a spherical dome rather than a rectangular dome, the inside capsule is more visible.
In a preferred embodiment of the invention, the maximum height of the body wall above the base wall is preferably less than or equal to the maximum width of the base wall. The base wall is preferably generally circular but other dome shaped body portions according to the invention are envisaged. For example, dome shapes having rectangular, oval, square and triangular bases are envisaged. The base of the dome may be substantially flat. Alternatively, the base may be somewhat concave or convex. In any case the resulting capsule is aysmmetrical about the base wall, although of course there can be one or more planes of symmetry perpendicular to the base wall.
The water soluble film, at least of the body wall, is thermoformable and, in one embodiment of the invention, is polyvinyl alcohol, or a polyvinyl alcohol derivative. Preferably the water soluble film of the base wall is the same material as that used to make the body wall. It is important that the body wall be thermoformed rather than cold formed because applicants have discovered that cold forming stresses the film and weakens the end capsule as a result.
Preferably the film has a thickness of between 10 and 1000 microns. More preferably the film has a thickness of between 20 and 80 microns.
The substance contained within the capsule may be a liquid, a gel or a paste. The liquid may have a viscosity between 100 and 45000 centipoise, more preferably between 200 and 30000 centipoise. A relatively 'thin' liquid allows the inner capsule to move more freely within the outer capsule. In this case the viscosity may be between 500 and 700 centipoise, and most preferably about 600 centipoise, when measured at 20°C at shear rate of 20 s^-1.
However, a thickened liquid/gel may be used. In the case of a machine dishwashing composition, this has the advantage that solid particulate matter e.g. wax encapsulated ingredients (bleach) may be homogenously suspended throughout the body of the liquid/gel providing a pleasing visual appearance.
In a preferred embodiment of the invention the substance is present in an amount of between 10 and 500ml, preferably between 10 and 100 ml, most preferably between 10 and 50 ml. Suitably, the capsule contains between 20 and 30 ml of a fluid composition. In a particularly preferred embodiment of the invention the fluid composition is a laundry treatment agent such as a laundry detergent, fabric conditioner or fabric care formulation. However, other compositions for domestic consumer use may be envisaged, such as disinfectants, personal care products, and the like.
Preferably the composition is substantially non-aqueous, comprising less than 80% water.
The inner spherical capsule may be formed from any of the above mentioned materials as used to make the outer capsule. It may be formed by any suitable technology, e.g. as described in WO97/35537, WO00/27367 or WO01/03676 by Bio Progress Technology.
The invention also relates to a process for producing a capsule according to the invention, the process comprising the steps of:

thermoforming a first sheet of a water soluble material to form a domed body wall of the body portion;
placing the fluid substance in the body portion;
placing a spherical inner capsule in the body portion;
superposing a second sheet of a water soluble material over the first sheet; and
sealing the first and second sheets along a continuous region of the superposed sheets surrounding the substance to form a base wall of the body portion.

Preferably the second sheet is superposed over the first sheet such that a small amount of air is entrapped in the outer capsule.
In a variation of the above process, the spherical inner capsule might be dosed before placing the fluid in the outer capsule.
In one preferred process the first sheet of water-soluble material is thermoformed by means of a heating plate. Preferably, the sheet of water-soluble material intimately contacts the heating plate, typically by applying a vacuum between the heating plate and the sheet of water-soluble material. Generally, the vacuum applied will be of less than 0.6 Bar. Alternatively the sheet may be blown into contact with the heating plate. The thermoforming sheet can be blown or sucked off the heating plate and into a suitable dome-shaped mould. In one aspect of the invention, the process includes an additional step of, prior to the addition of the fluid substance, applying a vacuum to the thermoformed body wall to maintain the shape of the body portion at least until after the heat sealing step.
The invention also relates to a process for the machine washing of laundry by employing a capsule according to the invention, wherein the fluid substance contained within the capsule comprises a laundry treatment agent, the process comprising the steps of:

placing at least one delivery product into the machine along with the laundry to be washed; and
carrying out a washing operation.

The invention will be more clearly understood from the following description of an embodiments thereof, given by way of example only, with reference to the accompanying drawings in which:-

The capsules of the invention are illustrated with reference to the drawings in which:
- Figure 1 shows a perspective schematic view of a delivery product for Laundry or machine dishwashing use according to one aspect the invention.

Referring to the drawing, a laundry delivery product 1 for delivery of a predetermined amount of first and second laundry fluids 2,4, the product comprising an outer water soluble capsule 6 containing a first fluid 2 for release on dissolution of the outer capsule 6 and an inner capsule 8 containing a second fluid substance 4 for release on dissolution of the inner capsule 8; wherein the inner capsule 8 is spherical.
The spherical inner capsule 8 is formed from PVA (Cold water soluble film sold under trade name Hi-Selon form Nippon Gohsei) using rotary form fill and sill technology, with pre-wetting of film to aid elasticity as disclosed in Wo97/35537.
The inner capsule 8 contains 3 ml of said second fluid 4 which comprises ca. 80% aqueous solution of MEA-neutralised citric acid as follows:

Water 16
MEA 39.21
Citric Acid 1 aq 44.79
Having water activity of 42%

The MEA-citrate 4 is dosed into the hemispherical cavities of used to form the spherical capsule 8, water sealing is achieved by simply forcing the two capsules against each other in the rotary die. The balls are then dried in a tumble dryer and left at 20 degrees C and 50 RH for two days.
To make the outer capsule 6, a thermoforming process is used where a number of capsules according to the invention are produced from two sheets of water soluble material. In this regard recesses are formed in the sheet using a forming die having a plurality of cavities with dimensions corresponding generally to the dimensions of the capsules to be produced. Further, a single heating plate is used for thermoforming the film for all the cavities, and in the same way a single sealing plate is described.
A first sheet of polyvinyl alcohol film is drawn over a forming die so that the film is placed over the plurality of forming cavities in the die. Each cavity is generally dome shape having a round edge, the edges of the cavities further being radiussed to remove any sharp edges which might damage the film during the forming or sealing steps of the process.
Each cavity further includes a raised surrounding flange. In order to maximise capsule strength; the film is delivered to the forming die in a crease free form and with minimum tension. In the forming step, the film is heated to 100 to 120°C, preferably approximately 110°C, for up to 5 seconds, preferably approximately 700 micro seconds. A heating plate is used to heat the film, which plate is positioned to superpose the forming die. During this preheating step, a vacuum of 0.5 bar is pulled through the pre-heating plate to ensure intimate contact between the film and the pre-heating plate, this intimate contact ensuring that the film is heated evenly and uniformly (the extent of the vacuum is dependant of the thermoforming conditions and the type of film used, however in the present context a vacuum of less than 0.6 bar was found to be suitable) Non-uniform heating results in a formed capsule having weak spots. In addition to the vacuum, it is possible to blow air against the film to force it into intimate contact with the preheating plate.
The thermoformed film is moulded into the cavities blowing the film off the heating plate and/or by sucking the film into the cavities thus forming a plurality of recesses in the film which, once formed, are retained in their thermoformed orientation by the application of a vacuum through the walls of the cavities. This vacuum is maintained at least until the capsules are sealed. Once the recesses are formed and held in position by the vacuum, the composition, in this case a non-aqueous liquid detergent and the inner capsule 8 is added to each of the recesses.
A second sheet of polyvinyl alcohol film is then superposed on the first sheet across the filled recesses and heat-sealed thereto using a sealing plate.
In this case the heat sealing plate, which is generally flat, operates at a temperature of about 140 to 160°C, and contacts the films for 1 to 2 seconds and with a force of 8 to 30kg/cm², preferably 10 to 20kg/cm². The raised flanges 16 surrounding each cavity ensure that the films are sealed together along the flange to form a continuous seal. The radiussed edge of each cavity is at least partly formed by a resiliently deformable material, such as for example silicone rubber. This results in reduced force being applied at the inner edge of the sealing flange to avoid heat/pressure damage to the film.
Once sealed, the capsules formed are separated from the web of sheet film using cutting means. At this stage it is possible to release the vacuum on the die, and eject the formed capsules from the forming die. In this way the capsules are formed, filled and sealed while nesting in the forming die. In addition they may be cut while in the forming die as well.
During the forming, filling and sealing steps of the process, the relative humidity of the atmosphere is controlled to ca. 50% humidity. This is done to maintain the heat sealing characteristics of the film. When handling thinner films, it may be necessary to reduce the relative humidity to ensure that the films have a relatively low degree of plasticisation and are therefore stiffer and easier to handle.
The outer capsule 6 contains a liquid detergent composition. When a liquid detergent composition is used, it is preferred that the composition is essentially non-aqueous. However, compositions may be used which contain substantial amounts of water, provided that this water is in a form where its chemical activity is reduced (e.g. as water of crystallisation or in combination with a solvent such that its vapour pressure is reduced) such that the soluble film does not dissolve prematurely.

An exemplary Laundry formulation fluid contained in the outer capsule comprises the following:

Ingredient	wt%
Alcohol Ethoxylate Nonionic (5EO)	25
LAS (alkylbenzene sulphonic acid, as acid)	20
Coco fatty acid	17
Glycerol	10
Monoethanolamine	8
Enzymes	1
Monopropylene Glycol	15
Minors	1
Water	Balance
	100%

Another suitable Laundry formulation is:

liquid properties

formulation See next table

colour Clear, transparent, colourless

viscosity 270 mPas

refractive index 1,333 @ 20°C

formulation

ingredient Level [%]

Nonionic 7EO 20.0

Monopropylene glycol 23.0

Monoethanol amine 9.6

LAS acid 20.5

Fatty acid 17

Minors 5.0

Water up to 100

As an alternative to a laundry capsule, an exemplary machine dishwashing formulation for the outer capsule is given below:

	Composition for Outer capsule
NaOH (50%)	0.740
Potassium tripolyphosphate	40.000
Glycerol (99%)	15.000
Nonionic surfactant	4.500
Antiscalant polymer	1.500
hydrophobically modified polycarboxylate	0.500
Phosphonate sequestrant	0.900
Na bicarbonate	4.500
Na sulfite	0.100
Carbopol thickener	1.180
Perfume	0.150
Dye	0.002
Wax encapsulated bleach catalyst	2.000
Water	balance to 100

	Composition for Inner capsule
Monoethanolamine	70
Protease	5
Amylase	4
Sodium perbonate (50 µ size)	21

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiments which are described by way of example only.

Claims

A delivery product for delivery of a predetermined amount of first and second fluids, the product comprising an outer water soluble capsule containing a first fluid substance for release on dissolution of the outer capsule and an inner capsule containing a second fluid substance for release on dissolution of the inner capsule, wherein the inner capsule is spherical.
A delivery product according to claim 1 wherein the inner capsule is constructed with seals located internally.
A delivery product according to claim 1 or claim 2 wherein the outer capsule has a dome shaped body portion for containing the first fluid.
A delivery product according to claim 3 wherein the dome shaped body portion comprises a first sheet of a water soluble material thermoformed to form a body wall of the body portion, and a second sheet of water soluble material superposed on the first sheet and sealed thereto along a continuous region of the superposed sheets to form a base wall of the body portion.
A delivery product according to any preceding claim, characterised in that the maximum height of the body wall above the base wall is less than or equal to the maximum width of the base wall.
A delivery product according to any preceding claim, characterised in that the base wall is generally circular.
A delivery product according to any of claims 1-5, characterised in that the base wall is generally oval.
A delivery product according to any preceding claim, characterised in that the base wall is generally flat, or concave or convex.
A delivery product according to any preceding claim, characterised in that the first sheet of water-soluble film comprises polyvinyl alcohol or a polyvinyl alcohol derivative.
A delivery product according to any preceding claim, characterised in that the second sheet of water soluble material comprises polyvinyl alcohol or a polyvinyl alcohol derivative.
A delivery product according to any preceding claim characterised in that the inner capsule material comprises polyvinyl alcohol or a polyvinyl alcohol derivative.
A delivery product according to any preceding claim, characterised in that the fluid substance is a liquid, paste or a gel.
A delivery product according to any preceding claim, characterised in that the fluids are domestic consumer products.
A delivery product according to claim 13, characterised in that the fluids are laundry detergent compositions.
A delivery product according to any of claims 1 to 14 characterised in that the fluids are a machine dishwashing compositions.
A delivery product according to any preceding claim wherein the outer capsule has gas entrapped therewithin.
A process for producing a delivery product for delivery of a predetermined amount of first and second fluids, the product comprising an outer water soluble capsule containing a first fluid substance for release on dissolution of the outer capsule and an inner capsule containing a second fluid substance for release on dissolution of the inner capsule, wherein the inner capsule is spherical, said outer capsule having a body portion containing the first fluid substance, characterised in that the process comprises the steps of:
• thermoforming a first sheet of a water soluble material to form a domed body wall of the body portion;

• placing the fluid substance and inner capsule in the body portion;

• superposing a second sheet of a water soluble material over the first sheet; and

• sealing the first and second sheets along a continuous region of the superposed sheets surrounding the substance to form a base wall of the body portion.
A process according to claim 17 wherein the second sheet is superposed over the first sheet such that a small amount of air is entrapped in the outer capsule.
A process according to claim 17 or 18 for producing a delivery product according to any of claims 1 to 15.
A process according to claims 18 or 19, characterised in that the first and second sheets are heat sealed.
A process according to claims 18-20, characterised in that first sheet of water-soluble material is thermoformed by means of a heating plate.
A process according to any of claims 18-21, characterised in that prior to the addition of the fluid a vacuum is applied to the thermoformed body wall to maintain the shape of the body portion at least until after the sealing step.
A process for the machine washing of laundry by employing a capsule according to any of claims 1 to 16, characterised in that the fluids contained within the product comprise a laundry treatment agent, the process comprising the steps of placing at least one capsule into the machine along with the laundry to be washed; and carrying out a washing operation.
A process for machine washing of dishes and the like by employing a delivery product according to any of claims 1 to 16, characterised in that the fluids contained within the product comprise a machine dishwashing detergent, the process comprising the steps of placing at least one capsule into the machine along with the dishes etc to be washed; and carrying out a washing operation.