GB2337997A - Dispensing device for detergent tablets - Google Patents

Abstract

A device is for dispensing one or more laundry treatment talets in a washing machine, and comprises a tube of flexible netting material with the ends tucked inside the tube and the whole held together and held predominately flat by being bound through the layers of net where the end is tucked in. The material can be a mesh, net, mat or other porous structure with preferably a pore sice of 1-5 mm. The binding means can be stitching, spot welding, glueing or the use of fasteners. A preferred embodiment of the invention consists of the above with a V cut in the tuck. The in-turned wall forms a pocket with the underlying net material in which pocket the tablet tends to lodge.

Description

2337997 1 A DETERGENT TABLET DISPENSING DEVICE The present invention

relates to a dispensing device for detergent tablets such as those used in the washing of laundry in an automatic washing machine.

Laundry washing detergents are available in many physical forms. The present invention is concerned with such detergent in tablet form. Detergent tablets are generally composed from compacted detergent powder and are convenient in that they enable a user to introduce a predetermined dose into a wash easily.

In the interests of convenience it is desirable to limit the number of tablets required per wash without limiting the amount of active detergent. Since detergent tablets necessarily incorporate tablet dissolution aids the resulting tablet size may be relatively large to an extent that it is generally not possible to ensure that it will fit in the conventional detergent dispensing drawer of all washing machine designs. It is therefore desirable to place the detergent tablet directly into the wash area, typically, the drum of a front-loading washing machine. This has been the practice for some time with concentrated detergent powders or liquids. Such a method of detergent dosing brings undissolved detergent into intimate contact with dyes and fabrics and can result in dye and fabric damage. Such damage is typically worse with a tablet composition as this will generally remain in an undissolved state for a longer period of time.

It is known to provide a detergent tablet dispensing device in order to reduce the possibility of fabric and dye damage. Several examples are disclosed in United Kingdom Patent Application No. 9704782.3 (publication no. 2323606). In designing a detergent tablet dispensing device other parameters need to be considered such as, for example, the accessibility of water to the tablet and the retention of semi-dissolved particles of the tablet. The importance of these factors is to some extent dependent on the tablet size and in particular its surface area. In addition, it is important that the device is easy to use, is of low cost, lends itself to mass production and does not include moving parts that may affect the reliability of the device.

GB registered designs 1056695, 1051081, 1051082 (Henkel) 105525 (Unilever) show examples of detergent dispensers which require a moving part to 2 enable opening and sealing of the device. The dispensers typically have a reduced porosity and hence are unsuitable for the delivery of tabletised products. Other variations on the design avoid the use of a moving part by forming a funnel opening down which powder or liquid may be poured to fill the device prior to use. This arrangement is obviously unsuitable for a tabletised product. GB registered designs 1051882, 1051881, 1055200 (Henkel), 2001868, 2031367 (Unilever) are examples.

A higher surface porosity is achieved by the dispenser device shown in EP 0 343 070 (Procter) by providing a net with a fixed opening. The device is also devoid of moving parts. It is however, unsuitable for tabletised products as the opening is screened by a 'propeller' type construction to retard powder loss. Simply removing this construction would result in any tablet introduced simply falling out again.

EP 0343 069 (Procter and Gamble) describes a dispenser with a net open at one end. The open end is sealed by a screw-on cap or by a sprung rim. The first device is complex and has moving parts and hence has limited convenience and is costly. The second device in practice requires the combination of materials of different properties (net with spring opening) along with it thereby making it costly. Both devices deliberately incorporate a closure to seal the open end of the net. EP 0 473 532 (Procter and Gamble) describes another similar device with an internal agitator to aid dissolution.

EP 0 691 102 (Procter and Gamble) describes a rigid cage with a moving part in the form of a closeable door or latch mechanism. EP 0 699 410 (Procter and Gamble) also describes a latch type mechanism to clamp a detergent tablet in a holder. These devices are formed from a rigid cage of coarse construction. Whilst such a design allows ready access of water to the tablet it has limited effectiveness in stopping contact of cloth with a detergent tablet and also serves to shield the dissolving tablet from the benefit of agitation communicated through the cage.

EP 576 234 (Unilever) consists simply of a tube of elasticated netting. which encloses the tablet, keeping it in place. This arrangement possesses many desirable qualities but has several practical limitations. First, to grip the tablets effectively the net must be strongly elasticated, which makes it difficult to open and to insert tablets, c 3 particularly more than one. Reduced elasticity would lead to tablets falling out of the net as they reduce in size during dissolution. Furthermore elastication rapidly degrades at high wash temperatures reducing the utility of the design.

It is an object of the present invention to obviate or mitigate the aforesaid disadvantages and to provide for an improved detergent tablet dispensing device that meets the requirements referred to above and protects textile being washed from damage.

According to the present invention there is provided a detergent tablet dispensing device for one or more detergent tablets, the device comprising a substantially flat receptacle having opposed walls of flexible porous material between which there is defined at least one opening through which a tablet may pass, wherein at least one end of the wall material around the opening is in-turned and secured to part of the rest of the wall, the in-tumed end serving, in use, to restrict the opening so as to prevent inadvertent release of the tablet.

The design of the present invention prevents inadvertent release for the duration of the wash as the tablet reduces in size through dissolution.

In a preferred embodiment it is an edge of the in-turned end that serves, in use, to prevent inadvertent release of the tablet.

There may be only one opening with all other wall ends being scaled so as to close the receptacle. Alternatively, the receptacle may have two opposed openings.

The in-turned end(s) may be secured to rest of the wall by means of stitching, heat-welding, fasteners or bonding agents.

The porous material is preferably of a net structure and may be substantially inelastic.

In a preferred embodiment at least one of the walls has a cut so as to enable relative inward deflection of part of the wall and thus provide improved tablet retention. The cut may comprise a Ushape or V-shape and preferably extends across the full extent of the wall. The cut is ideally disposed adjacent the edge of the inturned ends.

4 Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a first embodiment of a dispensing device of the present invention; Figure 2 is a side view of the dispensing device of figure 1; Figure 3 is an end view of the device of figure 1; Figure 4 is a perspective view of a second embodiment of a dispensing device of the present invention; Figure 5 is a side view of the device of figure 4; Figure 6 is an end view of the device of figure 4; Figure 7 is a perspective view of a third embodiment of a dispensing device of the present invention; Figure 8 is a side view of the device of figure 7; Figure 9 is an end view of the device of figure 7; Figure 10 is a perspective view of a fourth embodiment of a dispensing device of the present invention; Figure 11 is a side view of the device of figure 10; and Figure 12 is an end view of the device of figure 10 Referring now to the drawings, the exemplary dispensing device of figures 1 to -3 is constructed from two rectangular and contiguous layers of planar net material 1 that are sealed together at two opposed edges 2 and have opposed openings 3, 4 at the remaining two edges. The ends 5 of the material are in-turned at the openings '), 4. The device as a whole is substantially flat with the in-turned ends being secured (at 6) to an underlying portion of the main part of the net material layer by any suitable means as described below. The ends are secured at spaced locations so that the region defined between the secured locations, the in-turned end and the underlying portion of the layer of net material defines a pocket.

In use a detergent tablet is passed through one of the openings 3, 4 so that it is held between the opposed layers 1 and retained from inadvertent release through the opening's 3, 4 by the in-turned ends 5. The device is then ready to be placed into the drum of a washing machine. During the wash cycle the edges of the in- turned ends and the pockets prevent the tablet from escaping from the dispensing device. Generally, the detergent tablet tends to lodge, at least in part, in one of the pockets.

The net material is of semi-rigid construction and is ideally of plastics material with inelastic properties or a limited degree of elasticity. Significant elasticity is to be avoided if this results in the dispensing device gripping the tablet. Suitable materials for the net are available as continuous extruded cylindrical nets of polypropylene or polyethylene, although other materials such as nylons and polyesters may be used. Net material containing natural rubber, butyl, Lycra (RTM) or similar materials is not a preferred embodiment of the present invention but is not excluded so long as the materials do not serve to constrain a tablet in the device by virtue of their elasticity. The net structure may optionally be reinforced with fibres. Alternatively, a woven or non-woven mat material may be used so long as it is in the form of an open net structure. In summary, the material can be a mesh, net, mat or other porous structure. The pores of the structure need to be open to allow the free flow of water and small enough to effectively shield the fabric and retain the tablet. A maximum pore size if 5mm and a minimum of Imm is therefore preferred. A more preferable hole size is in the range 2 to 4mm.

The layers of net may be sealed together at the opposed edges 2 by stitching using any suitable filament. A filament of the same colour of the bag material is preferable. Alternatively, the layers of material may be sealed by spot welding. The spot welding process may optionally include the addition of polymeric material to bind the open net structure together. Other suitable seals may be provided by gluing or fasteners of any suitable material. Similar methods may be used to secure the inturned ends to the main part of the layers (as indicated by reference numeral 6 in the drawings).

The device may additionally have a toggle or other large protrusion attached to it or attached by a short cord, ribbon or similar method to reduce the possibility of the device 'posting', ie passing between the inner and outer drums of the washing 6 machine. The net material may also be indented, woven or otherwise constructed to display instructions, a trademark, logo or other such information, The tablet may consist of one two or more layers. To produce tablets containing two or more layers, the formulations for the first and second layers are produced separately and then introduces as separate layers into the die of a tableting press and co-compressed. The component(s) may be in one or both layers or may be split across the layers. Detergent tablets suitable for use will typically contain surfactant, water softer and other components, as known in the art.

A pressure of 10OkPa to 1000 MPa will generally be suitable for forming the tablet. There are a number of models of tableting press which are capable of producing dual layer tablets, for instance the "Excelapress" and "Rotapress" models are produced by BWI Manesty of Liverpool. It is also possible to modify a single layer press to produce dual layer tablets, for instance an RS model, also of BWI Manesty, could be modified in this way.

The provision of two openings in the device of figures 1 to 3 is convenient for the consumer as the tablet may be introduced through either opening. It is also considered within the scope of the invention to provide for three or more openings in devices with more edges. For example, a device of pentagonal configuration (with five edges) may be constructed from two layers of material that are secured together at the five corner points and between which there are five openings of the kind described above. Sharp corners may be rounded so as to prevent snagging on clothing etc.

In the following description of alternative dispensing device embodiments features common to the embodiment of figures 1 to 3 are given the same reference numerals. The dispensing device shown in figures 4 to 6 differs from that already described only in that it has a single opening 3.

The alternative embodiments of the device shown in figures 7 to 12 include a slit or cut 7 in each layer of material. The cut extends across the full width of the layer and has a V-shaped or U-shaped portion and is designed to improve retention of the tablet in the device. The cut may, be conveniently disposed immediately adjacent to, or overlying, the edge of the in-turned ends.

Z:1 7 To facilitate manufacture design an unsymmetrical design (fig 10 to 12) is preferred as this enables the V shape to be cut without having residual diamond or squares shaped pieces of net to remove and discard. In this design closure of the end with the extended V is intended. It is observed that it may be similarly tucked inward and fastened open in a non-optimal though practicable configuration. Similarly any end which is closed may or may not be tucked in and may or may not have rounded corners.

In use, the V-shaped portion of the layer of net material is deflected inwardly towards the tablet so as to aid retention.

All the embodiments of the present invention are simple to manufacture and use and yet provide for improved dispensing performance without damage to the textiles being washed.

The width of the opening or openings in the dosing device are preferably from 1.2 to 2.0 times the diameter of the detergent tablet to be inserted. Most preferably 1.5 to 1.75 times.

The tube of net material may most conveniently be purchased as such but may also be made up of sub sections if required.

It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined in the appended claims. For example, the device may be of any suitable overall shape other than square and rectangular as shown in the drawings.

8 EXAMPLES

The invention will be further described with reference to the following non-limiting examples.

Tablet dimensions The examples were conducted using a cylindrical tablet of dimensions Diameter 44mirn Thickness 20mm Bevel on top and bottom edges at 45' of 2mm width.

Composition of tablet The composition below was prepared as a granulate of Bulk Density 0.700,. cc, using a fluidised bed, before tableting.

Component Weight % Coco Imido Propyl Betaine 60% solution. 3.0% Syriperonic A7 Nonionic surfactant 6.4% (ex ICI) Minor components (antifoam, CMC etc) 2.0% Sodium triphosphate L16 Grade 32.0% (Ex Albright and Wilson Ltd) Sodium carbonate light grade 7.2% (ex Brunner Mond Ltd) S odium S ilicate C 100 as water glass -3.5% (ex Crossfield)

Sodium Silicate dry powder Csol 4.7% (ex Crossfield)

Sodium Perborate Tetrahydrate 21% (Ex Degussa Ltd) TAED 4% (Ex Hoechst) Laundrosil DGA 20.0% (ex S ud Chemic Ltd) Loss of water on evaporation Balance Total 100% 9 Tablet compression The tablets were made at a pressure of 5000 kPa using a tableting press "Rotapress" model RS produced by BWI Ma-nesty of Liverpool.

Dispensing device construction The dispensing devices of the invention were constructed of polypropylene netting of thickness 0.5mm with square holes of 4nim on the diagonal (urdess specified otherwise), this 0 material was Part No. OF100 ex Teriax Plastics of Sheffield. Other grades used were of lmm on the diagonal Part No. OFOSO and 8rnm on the diagonal Part No. OF 150. All nets were

0 15cm long and 9.5cm wide with a tuck in at the deepest point of 2.5cm unless otherwise specified.

EXANTLEI A1 t C bility to retain a tablet inserted in to the net. One tablet was inserted in a net of he d sign specified and the net was then.shaken at approximately 60Hz by hand through a height of about 6 inches with its open end downwards. This was repeated four times for each design until the tablet was either lost or for 2 minutes whichever was the shorter.

Dispenser Averaee time 0 Comparative example A 34 seconds A net made of Netlon as available from Netion Ltd. UK of-3cm diameter as described in EP A 0 576 234 (Unilever).

Comparative example B > 2 minutes A 'pepper pot closed device' made to scale after the design shown in Registered Design 1055525 (Unilever) Net as shown in fig. 1. 100 seconds Net as shown in fia. 4 93 seconds Net as shown in fig. 7 > 2 minutes Net as shown in fi 10 > M -7 inutes EXANTLE2 The dispensina device containina two 40g tablets was placed in the middle of a scaled pillow 0 -3 C> case lined with P 1 bleach sensitive cloth (available from the Society of Dyers and Colourists), This wash placed in the middle of the drum of a Hot oint Ultima 1200 using the 40'C wool P 1_) wash cycle containing 4ke, of terry towel ballast load. The machine wash was stopped at the W end of the main wash and the dosing device along with any tablet residue removed. The any residue was dried overnight at 105'C and weighed. The level of bleach damage was also measured as a change in reflectance using the Z scale as measured with a Hamison 50 reflectometer.

Dispenser Weight of tablet Reflectance change remaining (Bleach damage) Comparative example A Nil 5.1 A net made of Netlon as available from Netlon Ltd. UK of (3cm diameter 15cm long) as described in EP A 0 576 234 (Unilever).

Comparative example B 50g 0.5 A 'pepper pot clos ed device'. made after the design shown in registered design 1055525 (Unilever) Net as shown in fig. 1. Nil 3.2 Net as shown in fig. 1. Net grade OF050 9.5 g 1.2 Net as shown in fig. 1. Net grade OF 150 Nil 3.8 Net as shown in fig. 4 Nil Net as shown in fig. 7 Nil 3.4 Net as shown in fig. 10 Nil 3.2 The elasticated net gives full dissolution but a greater potential exposure of the tablet to the fabn'c. Not wishing to be bound by theory the stretched net will hold tight against the tablet whereas the nets of the invention can have some spacing between tablet net a-nd cloth.

c The pepper pot dispenser gave little dama.e but stopped the tablet dissolvine, w W,

Claims (1)

1. A detergent tablet dispensing device for one or more detergent tablets, the device comprising a substantially flat receptacle having opposed walls of flexible porous material between which there is defined at least one opening through which a tablet may pass, wherein at least one end of the wall material around the opening is in-turned and secured to part of the rest of the wall, the in-turned end serving, in use, to restrict the opening so as to prevent inadvertent release of the tablet.

   2. A detergent tablet dispensing device according to claim 1, wherein an edge of the in-turned end serves, in use, to prevent inadvertent release of the tablet.

   3. A detergent tablet dispensing device according to claim lor 2, wherein a pocket is defined between the in-turned ends and an underlying part of the rest of the wall.

   A detergent tablet dispensing device according to claim 1, 2 or 3), wherein there is provided one or more openings with all other wall ends being sealed so as to close the receptacle.

   5.

   A detergent tablet dispensing device according to any one of claims 1 to 4, wherein the porous material is substantially inelastic.

   A detergent tablet dispensing device according to any preceding claim, c t> wherein at least one of the walls has a cut so as to enable relative inward deflection of part of the wall.

   A detergent tablet dispensing device according to claim 6, wherein the cut comprises a U-shape or V-shape portion.

   12 8.

   A detergent tablet dispensing device according to claim 6 or 7, wherein the cut extends across the full extent of the wall.

   9. A detergent tablet dispensing device according to claim 8, wherein the cut is disposed adjacent the edge of the in-turned ends.

   10. A detergent tablet dispensing device substantially as hereinbefore described with reference to figure 1 to 3, figures 4 to 6, figures 7 to 9 or figures 10 to 12 of the accompanying drawings.

   11. A method of treating fabrics in a washing machine comprises the steps of placing the fabrics into the washing machine, inserting at least one detergent tablet into a dispensing device according to any previous claim, placing the device and tablet into the machine and operating the machine.