Note: Descriptions are shown in the official language in which they were submitted.
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WATER SOLUBLE CAPSULES
This invention relates to water soluble capsule containing a
detergent composition.
Detergent compositions for machine washing of laundry are
provided in many forms such as free-flowing powders,
liquids. 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 of 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.
Encapsulation also offers other advantages over tablets in
that it allows for discretising of other forms of detergent,
e.g. liquid, gel, paste etc.
However an unexpected problem encountered with certain types
of water-soluble capsules such as 'pillow-shaped' capsules
(e. g. as shown in figures 3a and 3b of the drawings herein),
is that they can be susceptible to "lodging" i.e. the
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capsules become lodged in the rubber of the porthole of the
washing machine, primarily at the start of the wash. This
happens in particular in machines where the space between
the door and the drum is such that it can accommodate a
package. Lodging may delay dissolution of the capsule or
even prevent it. For instance, the trend in new machines is
to reduce the levels of water even to the extent that the
level of water is below the porthole; in such machines
lodged packages may not be dissolved in the main wash.
Merely delaying dissolution will have an effect on
performance and is also believed to increase the risk of
residues as discussed below.
A further problem is that limited wetting of a lodged
package may result in partial dissolution of the package
film resulting in a gelatinous/sticky residue which can
persist to the end of the wash. This is unpleasant for the
user who may then be faced with the task of physically
removing any residue which has become adhered to the door
seal.
The problem of lodging is compounded by tendency of many
users to over load the washing machine with laundry. In
this situation, if a water-soluble capsule becomes lodged in
the door porthole, the rotating laundry may then prevent the
capsule from entering the main wash.
Thus, the benefits-offered by encapsulation-can-be-severely
compromised by the susceptibility of certain packages to
lodging.
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It is an object of the present invention to provide a water-
soluble capsule containing a detergent composition, which
overcomes at least some of the above mentioned problems. In
particular, it is an object of the invention to provide a
water-soluble capsule which is less susceptible to lodging.
Accordingly, in one aspect, the invention provides a water
soluble capsule containing a detergent composition, the
capsule having four or more walls and characterised in that
the capsule has one or more protruding portions, the or each
protruding portion being formed from co-joined end portions
of respective three or more walls.
An surprising advantage of this configuration is that the
protruding portions provide a form of 'handles' by which the
capsule can, if lodged, be drawn into the rotating laundry
load from the door region. This reduces the possibility of
the capsule remaining lodged and undissolved throughout the
wash.
The or each protruding portion may be tapered, preferably to
provide one or more pointed protrusions. This provides a
capsule having a shape which is easily grabbed by the
rotating washing load.
In one preferred embodiment the capsule is in the form of a
tetrahedron (four-walled polyhedron). The tetrahedron may
be regular or irregular i.e. the walls may take the shape of
regular or irregular polygons. The tetrahedron shape is
advantageous in that it can be a fairly simple structure to
manufacture (as compared with other polyhedrons with more
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walls) and at the same time the shape provides four tapered
protrusions.
An additional advantage can be obtained, by the provision of
capsule walls which are substantially equal in shape and
size, so providing a generally regular shape. This can
enhance mobility (i.e. rolling motion) of the capsule
through the wash which means that the detergent contained
therein is more likely to be better distributed throughout
the wash and not concentrated in a single location. The
latter situation would result in some of the wash load being
damaged by contact with concentrated detergent and the rest
left unclean due to the low concentration of detergent.
Preferably the capsule walls are regular polygons - that is
to say the sides of all the walls are substantially equal in
length. This provides a more regular shape and further
enhances capsule mobility in the wash.
The water soluble capsule may be in form of a pyramid with
four or more triangular walls and a base wall, having five
protrusions. This is an alternative to the tetrahedron and
provides a high number of protrusions to enable the capsule,
if lodged, to be picked up by the wash as it rotates.
Preferably, the walls of the pyramid shaped capsule are all
substantially equal in size and/or shape. Further
preferably the triangular walls are regular polygons.
Whilst this shape is not entirely regular as the base will
not be the same shape and/or size as the walls, if the wall
portions are kept regular and equal, it increases the
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capsules mobility throughout the wash albeit not as
effectively as the regular tetrahedron referred to above.
The water soluble capsule may be made using vertical form
fill and seal techniques. With this arrangement, the
capsule may be formed into a polyhedron by adapting existing
vertical form fill and seal machinery, thereby reducing the
costs of producing capsules according to the invention.
Thus according to another aspect of the invention there is
provided a water soluble capsule containing a detergent
composition, the capsule formed from a flexible film
disposed in folded configuration and sealed with
a) one or more longitudinal seals; and
b) first and second end seals located at opposed ends of the
capsule,
characterised in that the first end seal (6) is
substantially orthogonal to the or each longitudinal seal
(4a,4b,4c) and inclined at an angle to the second end seal
(8) so as to provide a capsule in the shape of a tetrahedron
having one or more protruding portions, each protruding
portion formed from co-joined tapered end portions of three
walls.
To achieve a more regular shape (which is advantageous as
explained above) it is preferred that the relative
inclination of first and second end seals (6,8) is between
and 90 degrees, and particularly preferred that the first
and second end seals are orientated substantially orthogonal
30 relative to each other.
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The transition between adjacent walls may be slightly curved
(e.g. due to the force exerted by the contents of the
capsule, and the flexibility of the capsule material)
however, this should not effect the working of the invention
as long as the protrusions are formed each protruding
portion formed from co-joined tapered end portions of three
walls.
Whilst not essential, the edges between the capsule walls
may be formed with increased sharpness by, for example,
arrangement of one or more seals during formation, so that
one or more seals are orientated along respective one or
more edge portions of the capsule to give more distinct
edges.
The walls may be substantially flat, however, it this is not
essential, indeed the or each wall may have a slight
curvature e.g. due to the force exerted by the contents of
the capsule, and the flexibility of the capsule material.
The capsule may contain any form of detergent: liquid,
powder - which may be granulated, gel, paste or the like or
combinations thereof. The detergent composition may be a
laundry (fabric cleaning/treatment) detergent composition or
a dishwashing machines detergent composition and thus is
suitable for use in laundry (fabric) washing and dishwashing
machines.
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The invention will be more clearly understood from the
following description of some embodiments thereof, given by
way of example only, with reference to the accompanying
drawings in which: -
Figure 1 is a perspective view of a capsule according to
another form of the invention;
Figure 2 is a side view of the capsule of Figure 1;
Figures 3a and 3b are front and side views of a known pillow
shaped capsule containing a liquid detergent;
Figure 4 is a view of a capsule according to another form of
the invention;
Figure 5 is a view of a capsule according to another form of
the invention; and
Figure 6 is a view of capsule according to another form of
the invention.
Throughout the Figures common numbers are used to designate
similar features.
Referring to the drawings and in particular figures 1 and 2,
a capsule 1 according to one form of the invention is shown,
which contains a measured unit dose of flowable detergent
composition 2, which may be liquid, granulated powder, gel,
paste or a combination thereof. In the example shown in
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figures 1 and 2 the detergent is a liquid detergent (as
described below).
The capsule is in the form of a tetrahedron, having four
walls 10,11,12,13 of the polyhedron being inclined at an
angle of relative to each other wall 10,11,12,13.
The capsule is formed from a flexible film disposed in
folded configuration and sealed with one longitudinal seal
4a and first and second end seals 6,8 located at opposed
ends of the capsule 1. The first seal 6 is substantially
orthogonal to the longitudinal seal 4a and further it is
substantially orthogonal to the second end seal 8. The
capsule has four tapered protruding portions 30,32,34,36.
These are formed from the three co-joined tapered end
portions of respective three triangular walls 10,11,12,13.
The tapered end portions of the capsule each enclose an
angle of less than 90 degrees.
The capsule shown in the drawings is formed by a so-called
'vertical form fill and seal' machine (not shown).
Using such a machine, a flat web of thermoplastic film is
unwound from a roll and formed into a continuous tube in a
tube-forming section, by heat-sealing together the
longitudinal edges of the web to form a lap seal or a fin
seal which eventually forms the longitudinal seal 4a of the
capsule 1. The tube thus formed is then pulled down to a
filling station: A section of-the tube is flattened at a
sealing device positioned below the filling station, and the
first transverse seal is made, providing the first end seal
of the capsule 1 which is a fluid-impervious barrier.
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After the first transverse seal 6 has been made, the tube is
then moved down through a predetermined distance, and the
jaws of the sealing device are closed. The flowable
detergent is then caused to enter the tube, and fill the
tube upwardly from the first end seal 6. A second
transverse seal is then made at an angle orthogonal to the
first transverse seal 6, forming the second end seal 8 of
the capsule and trapping the flowable detergent composition
inside the capsule. This second end seal 8 is located just
above the fill-level in the tube to avoid trapping liquid in
the seal which would compromise the seal integrity.
The sealing and severing of successive end seals can be
performed by mutually transverse pairs of sealing bars which
are motor driven to make successive seals in mutually
transverse directions.
The filled package, now in the form of a tetrahedron pouch,
is either cut away or left in place. The second transverse
seal also forms the bottom seal of the next package, and the
process can be repeated to form the next package.
The sealing device for forming the transverse seals is
commonly an impulse sealer, wherein an electrical current
flows through the sealing element for only a fraction of the
sealing cycle. After the current has heated the sealing
element and melted the thermoplastic film, there is then a
cooling period-; during which t-he seal resolidifies.
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There are many variants on the ways such machines operate.
A typical vertical form, fill and seal machine is sold under
the trade name GV2K1 by Gainsborough Engineering Company.
A regular tetrahedron as shown in figure 1 can be formed by
adjusting the width of the tube (i.e. length of end seal) to
equal the length of the tube (length of the longitudinal
seal ) .
Referring to figure 4, the capsule 1 shown here is a
slightly skewed tetrahedron, whose walls are asymmetrical
(no seals shown). It is formed by orienting the first end
seal orthogonal relative to the longitudinal seal and
inclined at an angle of approximately 70-80 degrees to the
second end seal. However, despite the skewed shape, this
still functions to provide protruding portions.
Referring to figure 5, the capsule shown here is formed with
two longitudinal seals 4b and 4c along side edges (26,28) of
the capsule during formation. The polyhedron formed has a
greater number of distinct edges (22,24,26,28) where the
seals (4b,4c,6,8) are located (as compared say with the
capsule shown in figs 1 and 2).
Figures 6 shows another capsule according to the invention
(seals not shown). The capsule has five-walls and is
configured as a pyramid with 4 walls and a base.
In one embodiment a capsule according to the invention
contains a liquid detergent composition. When a liquid
detergent composition is used, it is preferred that the
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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.
In another embodiment One example of a detergent composition
used is as follows:
Raw material Level (weight
percent of total)
Nonionic 20.00
Surfactant (alcohol ethoxylate)
Linear Dodecylbenzene Sulphonic Acid 20.00
Fatty acid 17.00
Monopropylene glycol 22.35
Monoethanolamine 9.65
Water, perfume, minor ingredients 11.00
In another embodiment, capsules contain a granular laundry
detergent powder as follows:
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Base powder
Linear Dodecylbenzene SulphoniC Acid (Sodium salt)8.8o
Alcohol ethoxylate (C12 - C13 7 EO) 7.0%
C16 -C18 Carboxylic acid 1.00
Zeolite 29.6%
Anhydrous Sodium Carbonate 10.5%
Moisture, Salts, Minors 4.10
(All above in a granulated Base Powder)
Post-dosed ingredients
Sodium Percarbonate 18.0%
Tetracetyl ethylenediamine 3.5%
Sodium Disilicate 5.5%
Sodium Citrate 2.0%
Fluorescer, antifoam, speckles, enzyme, fragrance, minors
10.0%
In use capsules according to the invention can conveniently
be placed directly into the wash liquor where the film
dissolves, releasing the detergent composition. Dissolution
of the capsule, even if lodged initially, is aided by the
provision of protruding portions which are 'grabbed' by
rotating washing to pull the capsule into and through the
washing load. This reduces the possibility of undissolved
capsule film persisting throughout the wash..
It is of course to be understood that the invention is not
intended to be res-trioed to the - de-tails of- the- above
embodiments which are described by way of example only.
