Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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"WATER-SOLUBLE CONTAINER"
The present invention relates generally to a water-
soluble container.
Water-soluble containers as such are well-known and
have a variety of uses, such as in clothes washing. For
example, CA 1112534 describes a water-soluble container
for a detergent composition. The water-soluble material
may be, for example, polyvinyl alcohol (PVOH). This
document describes a single chamber with a film form wall
of constant thickness. Because the chamber wall is of
constant thickness, the entire wall must be dissolved
before any product can escape. In certain circumstances
product may be required quickly, before the time when the
entire container has dissolved.
According to the present invention there is provided
a water-soluble container comprising one or more discrete
chambers for containing product, at least part of the
wall of the or at least one of the chambers is adapted
to dissolve before the remainder of the chamber to allow
product to escape. This means that product can escape
from a chamber without requiring complete dissolution of
the chamber. This can be useful for decreasing the time
taken for product to be released. It can also allow for
a greater degree of control over when product is released
because the area required to be dissolved is reduced.
A container according to the present invention with
more than one chamber gives the possibility for a system
combining the advantage of not requiring a whole chamber
to dissolve before a product is released, together with
the possibility of sequential release of products. In its
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simplest form a chamber provided with the means for
allowing product to escape before complete dissolution
could be associated with a chamber not having those
means. More complicated systems could involve chambers
which allow products to escape after different times
before complete dissolution.
The ability of such containers to provide for
sequential release of multiple products is extremely
useful. For example, clothing washing usually includes a
detergent stage and a stage later in the washing cycle in
which a softening agent is introduced. Dish-washing
sometimes includes a detergent stage and a separate
rinsing stage. In many cases it would be preferable and
sometimes essential for different stages of washing
operations to be kept completely separate.
By providing for sequential release of products the
present invention removes the need for manual
intervention at different stages of washing cycles and
allows the complete washing product to be packaged and
supplied together.
The at least part of the wall will most usually be
an exterior surface of the container thereby releasing
ysroduct from the container when it dissolves . H~awe;°e?A~ ,
i.t is also possible that the at least. part of L:i~r~z ~w:;~
forms part of a chamber which is housed within another
chamber which itself includes water, whereby the contents
of the chambers are mixed when the at least part of the
wall dissolves. This might be useful, for example, if
the product in the inner chamber is activated by product
in the outer chamber. This allows activation in a
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controlled environment before the activated product is
released into the exterior of the container and could be
useful for products which become unstable once activated.
There are many ways in which the container could be
formed in order that product is released from the chamber
when the part of the wall dissolves. For example the
part of the wall could itself comprise a closure part
v~hich dissolves to form an opening in the chamber.
Alternatively, the part of the wall may define a
releasable part. When the part of the wall dissolves the
releasable part is released, itself as yet undissolved,
to form an opening in the chamber. For example, the
releasable part may be a panel and the at least part of
the wall at least partly surrounds the panel so that it
is released, either completely or partially, when the
part of the wall dissolves. Alternatively the part of
the wall may comprise one or more clip elements, such as
a hook. The clip elements initially clip the closure
part to the container but then dissolve and release the
releasable part. In this way only a small section of the
wall dissolves and yet a large opening can be provided
quickly.
There are many ways in which the part of the wall
r_.ould be formed in order that it dissolves before the
remainder of the container. For example, the at least
part of the wall could be made from a thinner section of
material and/or from a different material with a faster
rate of dissolution than the remainder of the container.
In embodiments where the at least part of the wall
is thinner than the remainder of the container the
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material thinning may be arranged on the interior surface
of the Chamber wall. This is particularly relevant when.
the at least part of the wall defines a thin channel,
because if the material thinning was arranged on the
exterior surface the channel could become saturated with
dissolved material, which would impede further
dissolution.
In order to simplify production and allow for high
volume production the container may be formed by
injection moulding. In embodiments where the at least
part of the wall is a thin section surrounding a panel,
the area of the panel may form the gate region for
injection moulding. This ensures that the thin section
is correctly moulded by avoiding problems with moulded
regions which are remote from the injection point.
As stated above, differential dissolution
characteristics may be achieved by forming the container
from two or more different materials at least some of
which are water-soluble. It may, however, be preferable
for simplification of the production process for the
whole of the container to be formed from the same
material.
In some embodiments at least part of the material
from which the container is formed is a polyvinyl
alcohol. Alternatively at least part of the material may
be a polylactic acid or a starch based material.
The container may be flexible. This may be as a
result of the choice of material and/or the thickness of
the walls.
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Where a container has several walls, the term "wall"
can refer to any one or more of the walls. A spherical
container, for example, has a single wall whereas a cube
has six walls. The term is therefore generic and could
5 refer to any part of the material defining the chamber.
The present invention will now be more particularly
described, by way of example, with reference to the
accompanying drawings, in which:
Fig 1 is a perspective view of a housing formed as
part of a container according to a first embodiment;
Fig 2 is a section along line II - II of Fig 2,
Fig 3 shows the housing of Fig 2 with a lid
component attached;
Fig 4 shows the container of Fig 3 following an .
initial exposure to water;
Fig 5 is a section thraugh a container according to
an alternative embodiment;
Fig.6 is a section of a container according to an
alternative embodiment; and
Referring first to Figs 1 and 2 there is shown a
housing 10 of generally parallelopiped shape comprising a
base wall 11, side walls 12, 13 and end walls 14, 15.
The housing is hollow and is open opposite the base 11 to
form a tray-like structure. The housing 10 is formed
from a water-soluble material. The material could be,
for example, a grade of PVOH which dissolves at
approximately 50°C. The interior of the housing 10 is
divided into two discrete chambers 30, 31 by spaced
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parallel partition side walls 16, 17 which extend from
end wall 15 and are joined at their ends by a partition
end wall 18. Each of the partition walls 16, 17, 18
extends the full height of the housing walls 11, 12, 13,
14, 15. The portion of the base wall 14 which is bounded
by the partition walls 16, 17, 18 includes a panel 19
surrounded by a region of material thinning 20 the
purpose of which will be described in more detail below.
Referring now to Fig 3 the housing of Figs 1 and 2
is shown forming part of a container 1. The housing 10
is closed by a lid 25. The chambers 30, 31 are filled
with different products before the lid 25 is applied.
The lid 25 includes a panel 26 and region of material
thinning 27 opposite arid identical to those of the
housing 10. The lid 25 may be secured to the housing 10
by any convenient means such as welding adhesion,
interference fit or clipping. In this embodiment the
seal is a face seal bond which is chemically activated,
in this case by water, and supported internally by a wall
28 depending from the lid 25.
In this embodiment the thickness of the housing
walls and the lid is approximately 0.4mm. This is about
the thinnest that material can be without a risk.. of 'pin.
holes' i.e. tiny holes in the material which could
compromise the integrity of the chamber. The material
thinnings are approximately 0.15mm thick and are formed
by reducing a small part of the uniform thickness of the
container.
In use, the container 1 is placed in an aqueous
environment and the temperature is raised beyond the
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dissolution temperature of the container material. As
the container 1 begins to dissolve the material thinned
regions 20, 27 will completely dissolve before the
remainder of the container. As a result, the panels 19,
26 are released from the lid 25 and the base wall 14 such
that product can escape from the chamber 31. Of course
the panels 19,26 do not have to be completely released to
be effective. For example the material thinned regions
20, 27 could extend part way round the panels 19, 26 such
that the panels 19, 26 become flaps which hinge open.
Product from the chamber cannot escape until the
remainder of the container has dissolved.
Referring now to Fig 5 there is shown an alternative
embodiment. In this embodiment two discrete chambers
130,131 are formed from two separate, hollow cube-shape
housings 110a,.110b which are bonded together along
adjacent side walls 112a, 112b. Each housing 110x, 110b
is open along one side but closed by a lid 125a, 125b, in
this embodiment sealed to the housings by adhesion. The
lids 125a, 125b are formed from different grades of PVOH
which dissolve at different rates, with the material of
the lid 125a having the faster dissolution rate. In this
embodiment therefore the lid 125a of the housing 110a
dissolves before the lid of housing 110b, to allow its
product to escape first.
Referring to Fig.6 there is shown a container 201
with a single chamber 230. A generally cuboid housing
210 comprises a base wall 221 and side walls 214, 215.
An open side of the housing 210 is closed by a lid 225.
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The lid 225 is held onto the housing 210, by a clip
220 extending from its periphery. The clip 220 engages
under a bead 235 formed around the open side of the
housing 210.
The clip 220 is thinner than the remainder of the
container 201. Accordingly, in use of the container the
clip 220 dissolves before the remainder of the container
so that the bead 235 no longer retains the lid 225, and
therefore allows the lid 225 to be released from the
housing 210.
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