ZA200204661B - Injection-moulded water-soluble container. - Google Patents

Description

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INJECTION MOULDED WATER-SOLUBLE CONTAINERS

The present invention relates to rigid, water- soluble containers. It also relates to capsules, in particular to capsule-like containers, in particular to such containers that may be utilised for the delivery into an aqueous environment of substances such as detergents, pesticides, biocides, deodorants, dyes and pigments, and water-treatment chemicals.

Clothes washing compositions may be delivered to a clothes washing machine by a delivery tray from which the composition is fed into the washing drum, or they may be placed directly into the washing drum. The washing compositions may be in powder, liquid or block form.

Liquid compositions have the disadvantage that they may be spilt. The same applies to powder compositions.

Powder compositions have the additional disadvantage that they may produce dust which can be inhaled. These problems are overcome or lessened when blocks of washing composition are used. These are normally individually wrapped. On unwrapping a block, for use, it is still possible that some dust may be produced. Additionally it is an inconvenience for the consumer to have to unwrap the block. Furthermore it is almost impossible for the user to avoid some contact between the block and his or her skin, so leading to a requirement for the user to . wash their hands after starting the washing machine. In or | fact, all of the methods described involve a risk of contact between the composition and the skin, and it is desirable in all cases for the user to wash their hands after starting the washing machine. In this context it

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® should be borne in mind that many compositions contain enzymes to assist the cleaning action. Even though the user may tolerate enzyme residues which may be left in clothes after washing, they may still not tolerate contact between the concentrated washing composition containing the enzymes, and the skin.

Similar considerations apply in relation to other areas including fabric care, surface care and dishwashing. Thus, in relation in particular to dishwashing compositions, there are also problems of spillage, dust generation, skin contact and inconvenience.

It is known to package chemical compositions which may be of a hazardous or irritant nature in water-soluble

Or water-dispersible materials such as films. The package can simply be added to water in order to dissolve or disperse the contents of the package into the water.

For example, WO 89/12587 discloses a package which comprises an envelope of a water-soluble or water- dispersible material which comprises a flexible wall and a water-soluble or water-dispersible heat seal. The package may contain an organic liquid comprising, for example, a pesticide, fungicide, insecticide or herbicide.

CA-A-1,112,534 discloses a packet made of a water- soluble material in film form enclosing within it a paste-form, automatic dishwasher-compatible detergent composition. The water-soluble material may be, for

AMENDED SHEET example, poly(vinyl alcohol), polyethylene oxide or methyl cellulose.

It is also known to form water-soluble containers by thermoforming a water-soluble material. For example, WO 92/17382 discloses a package containing an agrochemical such as a pesticide comprising a first sheet of non- planar water-soluble or water-dispersible material and a second sheet of water-soluble or water-dispersible material superposed on the first sheet and sealed to it by a continuous closed water-soluble or water-dispersible seal along a continuous region of the superposed sheets.

The above methods of packaging have, however, a number of disadvantages.

The first disadvantage is that they do not have a particularly attractive appearance. In fields such as containers used in the domestic environment, an attractive appearance for an article is extremely desirable. Liquids contained in envelopes of water- soluble film can have a limp, unattractive appearance.

The second disadvantage is that it is difficult to form two or more separate compartments in the packaging so that two incompatible components are both enclosed but separated from each other. Although an arrangement has been described to separate incompatible materials in flexible pouches in WO 93/08095, the method proposed is complex and is not currently achievable in large-scale manufacturing. It cannot, therefore, be used for producing large numbers of containers.

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The third disadvantage is that there is only limited control of the release profile of the compositions held in the containers. For example, when a composition is held between two planar water-soluble films or in a thermoformed package, the composition is simply released at the time when the films dissolve or disperse in water. ) While it may be possible to control to a certain extent the timing of the start of release of the contents, there can be no control over the rate of release of the contents since the entire film dissolves or disperses at about the same time. Furthermore it can be difficult to provide an extended time before the contents of the package are released. An additional problem also arises with thermoformed packages. If the thermoforming is not carefully controlled there may be inadvertent thinning of the film material at the points where the material is drawn down into the mould when it is thermoformed. This could release the contents of the package early.

Additionally, in all of the above packages, it is not possible to release different compositions at different times or at different rates since, as discussed above, it is not possible to incorporate more than one composition in each water-soluble container.

The fourth disadvantage is that the containers cannot be produced at a particularly fast rate. When the containers are produced by heat-sealing planar films or by thermoforming, the containers have to be immediately filled and sealed. All of these procedures have to be carried out in succession. This means that it is not possible to obtain a quick throughput for mass-market

AMENDED SHEET goods such as household products. For example, standard thermoforming machines can only produce around 400 to 800 containers per minute.

There are numerous forms of systems used in the delivery of medical preparations in the market place today. The two most dominant in relation to oral routes are capsules made from hard gelatine, and tablets - the so-called solid dose formulations. Both of these presentations have remained virtually unchanged for decades. Gelatine capsules are made by a dipping process, building up successive layers, while tablets are formed by compressing a powder or fine granules.

It has now been appreciated that the above type of capsule has utilisations other than in medicine and the human or animal body. In particular, it has been realised that many substances that must be packaged for delivery to their use site could, where that site is an aqueous environment, be contained in similar, though somewhat larger, capsules. Thus, a capsule-like container - a "capsular" container - could be employed to deliver, for example, detergents to a washing machine.

Moreover, by appropriately dimensioning the various parts of the container, or by suitably selecting the materials from which they are made, different parts of the container will in use dissolve at different times.

The present invention seeks to provide water-soluble containers which overcome some or all of the above disadvantages.

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The present invention has a number of different aspects and embodiments as follows:

The present invention provides a rigid, water- soluble container made of an injection moulded poly (vinyl alcohol) (PVOH), which container encases a fabric care, dishwashing, water-softening, laundry, rinse aid or antibacterial composition or a refill composition for a trigger-type spray.

The present invention also provides a rigid, water- soluble container made of an injection moulded cellulose ether, such as hydroxypropylmethylcellulose (HPMC), which container encases a fabric care, surface care or dishwashing composition.

The present invention also provides a capsule, i.e. a container, comprising a self-supporting receptacle part and a closure part, the receptacle part and the closure part together enclosing a fabric care, surface care or dishwashing composition, the receptacle part being formed of a water-soluble polymer, and the closure part being formed of a water-soluble polymer, wherein, in use, the closure part dissolves before the receptacle part.

The present invention further provides a capsule, comprising a self-supporting receptacle part and a closure part, the receptacle part and the closure part together enclosing a fabric-care, surface care or dishwashing composition, the receptacle part being formed of a water-soluble polymer, and the closure part being formed of a water-soluble polymer, wherein the water-

AMENDED SHEET soluble polymer of the receptacle part is a cellulose ether.

The present invention yet further provides an injection-moulded capsule container of any size or shape for the delivery of a water-destined ingredient selected from a fabric care, surface care or dishwashing composition, which container is made of a material that will dissolve in the intended aqueous destination site, said material not being a poly(vinyl alcohol).

The present invention also provides an injection- moulded capsule container of any size or shape for the delivery of a water-destined ingredient selected from a fabric care, dishwashing, water-softening, laundry, rinse aid or antibacterial composition or a refill composition for a trigger-type spray, which container is made of a : material that will dissolve in the intended aqueous destination site.

The present invention further provides a method of ware washing, comprising use of a container or washing capsule as defined above, the method entailing introducing the container or washing capsule into a ware washing machine prior to commencement of the washing process, the container or washing capsule being entirely consumed during the washing process. The ware washing machine may, for example, be a dishwashing or laundry washing machine.

The capsule container of the present invention may, for example, comprise at least two components made of one

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® or more material (s) that can be moulded and which are water soluble or water dispersible or in which a substantial part of the surface of these components is water soluble or water dispersible so as to leave perforations throughout the wall when the capsular container is placed in contact with an aqueous environment, wherein the container has one to six compartments, preferably one or two or three, the content of the various compartments being accessible to the aqueous environment when the capsular container is exposed to such an aqueous environment, the accessibility time of the various compartments being the same or different from one compartment to another compartment.

The following description and drawings all relate to each and every aspect and embodiment as discussed above, either singly or in any combination thereof.

The containers of the present invention overcome some or all of the above disadvantages.

Firstly, because the containers are rigid and self- supporting, they have an attractive, uniform appearance which does not vary between different containers.

Furthermore, the rigid containers can easily have various elements incorporated which are considered to be pleasing to the eye but which are impossible to incorporate in the flexible containers discussed above.

Secondly, because the containers are rigid, it is easily possible to introduce two or more compartments, or have larger compartments separated by walls, to separate

AMENDED SHEET mutually incompatible ingredients. The containers can also hold part of the composition on an external surface, for example in an indentation. Furthermore, the container can be moulded in almost any shape that might be useful. In particular it can be given raised or lowered areas. :

Thirdly, it is possible to control the release profile of the contents of the container. Since the container is rigid, it is possible to adapt the width of all of the walls of the container to control both the start of release of the composition as well as the rate of release. For example, one or more walls may be made thin in order to have an early release of the composition. Alternatively all the walls may be thick in order to ensure that there is a delayed release of the composition. The rate of release of the composition may also be controlled by ensuring that only part of the container has thin walls which are dissolved or dispersed before the remainder of the container. Different walls or parts of walls of the container may be prepared from different water-soluble polymers which have different dissolution characteristics. For example, a first compartment may be fully enclosed by a polymer such as

PVOH which dissolves at a higher or lower temperature than the polymer enclosing a second compartment. Thus different components can be released at different times.

If the container holds a solid or gelled composition, it is not even necessary for the container to fully enclose the composition. A part may be left exposed, so that it immediately begins to dissolve when added to water.

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Fourthly, since the containers are rigid and self- supporting, they can easily be filled on a production line using normal filling equipment. Such filling equipment is quite capable of filling at least 1500 containers per minute.

Desirably the container, apart from its contents, consists essentially of the injection-moulded polymer.

It is possible for suitable additives such as plasticizers and lubricants to be included. Plasticizers are generally used in an amount of up to 20 wt%, for example from 15 to 20 wt%, lubricants are generally used in an amount of 0.5 to 5% wt% and the polymer is generally therefore used in an amount of 75 to 84.5 wt%, based on the total amount of the moulding composition.

Examples of suitable polymers are PVOH and cellulose ethers such as HPMC.

PVOH is a known water-soluble material which is used to prepare water-soluble films for encasing compositions as discussed above. Cellulose ethers have not in general been used to prepare water-soluble films because they have poor mechanical strength.

PVOH materials, unlike gelatin, can be modified to dissolve at different rates under various conditions (including the pH of the aqueous medium into which they are introduced).

The PVOH preferably used to form the container of the present invention may be partially or fully alcoholised or hydrolysed. For example it may be from 40-

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® 100%, preferably 70-92 %, more preferably about 88%, alcoholised or hydrolysed polyvinylacetate. The polymer such as PVOH or cellulose ether is generally cold water (20°C) soluble, but may be insoluble in cold water at 20°C and only become soluble in warm water or hot water having a temperature of, for example, 30°C, 40°C, 50°C or even 60°C. This parameter is determined in the case of

PVOH by its degree of hydrolysis.

For certain applications or uses, polymers soluble in aqueous environments at temperatures as low as 5°C are also desirable.

In order to ensure that the polymer such as PVOH or cellulose ether is capable of being injection moulded, it is usual to incorporate components such as plasticizers and mould release agents in an amount of up to, for example, 15 wt% of the composition. Suitable plasticizers are, for example, pentaerthyritol such as depentaerythritol, sorbitol, mannitol, glycerine and glycols such as glycerol, ethylene glycol and ~ polyethylene glycol.

Solids such as talc, stearic acid, magnesium stearate, silicon dioxide, zinc stearate, and colloidal silica may also be used. A preferred PVOH which is already in a form suitable for injection moulding is sold in the form of granules under the name CP1210T05 by

Soltec Developpement SA of Paris, France.

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The PVOH may be moulded at temperatures of, for example, from 180-220°C, depending upon the formulation selected and the melt flow index required. It can be moulded into containers, capsule bodies, caps, receptacles and closures of the appropriate hardness, texture and solubility characteristics.

One of the great practical problems of current hard gelatine capsules is their ability to hold a static electrical charge. Such capsules in production rapidly pick up a high static charge which has the effect of making them not only stick to each other and to all other non-polar surfaces but also making them attract particles of foreign material from their surroundings. It also means that that the capsules are hard to fill, and that their surfaces must be treated immediately prior to printing. This phenomenon is common to some mouldable polymers, but not to PVOH, which is not only soluble, ingestible, mouldable and weldable, but in addition will not support a static charge capable of causing the problems described above. So, yet another consequence of using an injection-moulding method is that the mouldable material may be chosen having regard to its ability to pick up and retain a static charge - or may include one or more additional substances that has some effect on the way the capsule behaves in this respect.

One aspect of the present invention is, as indicated above, a capsule, i.e. a container, comprising a self- supporting receptacle part and a closure part, the receptacle part and the closure part together enclosing a composition such as a fabric care, surface care or

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Claims (39)

1. A rigid, water-soluble container made of an injection moulded poly(vinyl alcohol), which container encases a fabric care, dishwashing, water-softening, laundry, rinse aid or antibacterial composition or a refill composition for a trigger-type spray.

2. A rigid, water-soluble container made of an injection moulded cellulose ether, which container encases a fabric care, surface care or dishwashing composition.

3. A container according to claim 2 which encases a dishwashing, water-softening, laundry, detergent, rinse aid, disinfectant, antibacterial or antiseptic composition or a refill composition for a trigger-type spray.

4. A container according to claim 2 or 3 which comprises hydroxypropylmethylcellulose.

5. A container according to any one of the preceding claims which has two or more compartments.

6. A container according to any one of the preceding : claims wherein the composition has a mass of at least

15g.

7. A container according to claim 6 wherein the composition has a mass of from 15 to 40g. AMENDED SHE]

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8. A container according to any one of the preceding claims wherein the container is sealed by a water-soluble closure part in the form of a film or injection-moulded, rigid closure.

9. A container according to claim 8 wherein the closure part comprises a poly(vinyl alcohol) film or closure.

10. A container according to any one of the preceding claims which contains a dishwashing, water-softening, laundry or detergent composition or a rinse aid.

11. A container according to any one of claims 1 to 9 which contains a disinfectant, antibacterial or antiseptic composition.

12. A container according to any one of claimsl to 9 which contains a refill composition for a trigger-type spray.

13. A capsule comprising a self-supporting receptacle part and a closure part, the receptacle part and the closure part together enclosing a fabric care, surface care or dishwashing composition, the receptacle part being formed of a water-soluble polymer, and the closure part being formed of a water-soluble polymer, wherein, in use, the closure part dissolves before the receptacle part.

14. A capsule according to claim 13 wherein the water- soluble polymer is a poly(vinyl alcohol) or a cellulose ether. AMENDED SHEE]

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15. A capsule according to claim 14 wherein the water- soluble polymer is a poly(vinyl alcohol) and the composition is a fabric care, water-softening, laundry, rinse aid, dishwashing or antibacterial composition or a refill composition for a trigger-type spray.

16. A capsule according to claim 13 wherein the water- soluble polymer is a polyglycolide, gelatin, polylactide or polylactide-polyglycolide copolymer.

17. A capsule comprising a self-supporting receptacle part and a closure part, the receptacle part and the closure part together enclosing a fabric care, surface care or dishwashing composition, the receptacle part being formed of a water-soluble polymer, and the closure part being formed of a water-soluble polymer, wherein the water-soluble polymer of the receptacle part is a cellulose ether.

18. A capsule according to claim 17 wherein, in use, the closure part dissolves before the receptacle part.

19. A capsule according to any one of claims 13 to 18 wherein the receptacle part has side walls which terminate at their upper end in an outward flange, to which the closure part is sealingly secured.

20. A capsule according to any one of claims 13 to 19 wherein the closure part is a plastics film. AMENDED SHEET

21. A capsule according to any one of claims 13 to 20, wherein the composition comprises a powder, gel, paste Or low water liquid formulation.

22. A capsule according to any one of claims 13 to 21 wherein the receptacle part defines two or more compartments which contain different products.

23. A capsule according to claim 22 wherein the receptacle part comprises an upstanding wall which separates compartments thereof.

24. A capsule according to any one of claims 13 to 23 wherein the receptacle part comprises an outwardly facing opening into which a tablet is press-fitted.

25. A capsule according to claim 24 wherein the tablet comprises a material useful in a washing process.

26. A capsule according to any one of claims 13 to 25 wherein the closure part is a transparent or translucent material.

27. A capsule according to any one of claims 13 to 26 which is a washing capsule enclosing a washing composition.

28. A washing capsule according to claim 27 wherein the washing capsule comprises a tablet formulated for delayed and/or sustained release of a material. AMENDED SHEE!

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29. A capsule according to claim 27 or 28 wherein the washing composition contains an enzyme.

30. An array of washing capsules as defined in any one of claims 13 to 29 which are joined together but are readily separable from each other for use.

31. An array according to claim 30 wherein the array has a line of symmetry extending between capsules, and the two halves of the array are folded together about the line of symmetry, with the closure parts in face-to-face contact.

32. A method of manufacturing an array of washing capsules as defined in claim 30 or 31, which method comprises: forming an array of receptacle parts, each receptacle part being connected to adjacent receptacle parts but being separable from them by a snap or tear action; charging the receptacle parts with washing composition; and sealingly securing a sheet of a water- soluble polymer over the top of the array, to form the closure parts for all the receptacle parts of the array.

33. An injection-moulded capsule container of any size or shape for the delivery of a water-destined ingredient selected from a fabric care, surface care or dishwashing composition, which container is made of a material that will dissolve in the intended aqueous destination site, said material not being a poly(vinyl alcohol).

34. An injection-moulded capsule container of any size or shape for the delivery of a water-destined ingredient AMENDED SHEET selected from a fabric care, dishwashing, water- softening, laundry, rinse aid or antibacterial composition or a refill composition for a trigger-type spray, which container is made of a material that will dissolve in the intended aqueous destination site.

35. A container according to claim 34 wherein the material that will dissolve is a poly(vinyl alcohol).

36. A container according to claim 33 or 34 wherein the material that will dissolve is a cellulose ether, polyglycolide, gelatin, polylactide or polylactide- polyglycolide.

37. A container according to any one of claims 33 to 36 wherein the composition is a detergent, biocide, deodorant or water-treatment chemical.

38. A container according to any one of claims 33 to 37 which is in the form of an elongate tubular package with closed, rounded ends.

39. A method of ware washing, comprising use of a container or washing capsule as defined in any one of claims 1 to 12 or 27 to 38, the method entailing introducing the container or washing capsule into a ware washing machine prior to commencement of the washing process, the container or washing capsule being entirely consumed during the washing process. AMENDED SHEET