EP0345838A2

EP0345838A2 - Single-dose fabric treatment sachet

Info

Publication number: EP0345838A2
Application number: EP89201187A
Authority: EP
Inventors: Brian Edward Talkes; Colin James Lowery; Haydn Guy William Dickenson
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1988-05-18
Filing date: 1989-05-11
Publication date: 1989-12-13
Also published as: IE891611L; JPH0249697A; MX172133B; GB8811794D0; CA1332587C; EP0345838A3; AR244167A1; BR8902327A

Abstract

Single-dose fabric-treatment articles are disclosed, said articles being in the form of sachets made of flexible sheet material, wherein at least one opening side is equipped with one or more semi-rigid strips (2) which are curved in their normal, relaxed state, and are constrained in a straight position by closing means (3) of the opening side, and which upon opening of the closing means, gain a curved shape so as to form an open mouth for the dispensing of the fabric-treatment composition.

Description

The invention relates to single-dose articles which are suitable for treating fabrics in a washing machine, and which contain a fabric-treatment composition such as a detergent composition.
Although the marketing of detergent compositions packaged in bulk is common practice, it has been found that single-dose devices containing detergent compositions offer a number of advantages in terms of convenience of use and product efficiency.
In particular, these devices improve dosage control and considerably reduce loss of detergent composition caused by retention in the dispensers of washing machines.
Several kinds of single-dose detergent products have already been described in the art; a common property of these devices is their ability to discharge the detergent composition they contain during the wash cycle : bags which are made of water-soluble material have been disclosed, as well as bags made of water-insoluble material fitted with a water soluble seal, as in GB 1.583.082, or a mechanically-weak seal, as in EP-B-O 040 931.
Such sachet-type products have not always proved satisfactory in terms of product dispensing, and in the case of rectangular-shaped bags with openable seals, experience has showed that a single water-soluble or mechanically-weak seal is not sufficient to provide full dispensing of the detergent product. Such sachets need to have as many as three sides out of four which open in the washing-machine. When such seals are water-soluble seals, this execution proves a costly one, especially since the sachet material needs to be separately coated, either entirely, or in a suitable pattern, with a water-soluble material; in addition, with such a number of openable seals, the sachet is quickly transformed into a sheet by the action of water, thus discharging the content all at one time, and not in a more desirable gradual manner.
The present invention provides single-dose fabric-treatment products, in the form of sachets, which do not require several opening seals and which provide a gradual dispersing of the fabric-treatment composition they contain.
The fabric-treatment products of the invention are sachets made of flexible sheet material, having at least one opening side fitted with closing means which open when the sachet is in use in a washing machine, characterised in, that along both edges of said opening side,or along at least one of the edges in another embodiment, are permanently attached semi-rigid strips which are constrained in a straight position by the closing means, and which, upon opening of the closing means, gain a curved shape so as to form an open mouth for the dispensing of the fabric-treatment composition.
The rigidity of said semi-rigid strips must be such that the mouth formed upon opening of the closing means, is kept open throughout the wash cycle; thus allowing a complete, but gradual dispersing of the fabric-treatment material.
Another important advantage of the present open-mouth configuration is that the spent sachets run virtually no risk of being lost during the washing cycle, in the space between inner rotating drum and outer stationery drum of the washing machine; the passage of a sachet or sheet, in said space can disrupt the normal functioning of the machine; the problem has already been disclosed and solutions proposed, in EP-A-249 439. The devices of the present invention present the advantage of efficiently combining the functions of ease of dispensing and sachet-loss preventing.
the sachets of the present invention are preferably rectangular, and formed either from two rectangular sheets of flexible material bonded together at their four edges, or from a single sheet of flexible material folded over and with the remaining three edges bonded together.
It is essential, in the context of the present invention, that said sachets contain at least one opening side, i.e. a side which, while being closed by closing means before use of the sachet, opens up when in use in a washing machine, and allows dispensing of the fabric-treatment composition contained in it.
It is the main characteristic of the invention that at least one of said opening sides is fitted with semi-rigid strips which are constrained in a straight position by the closing means, and which upon opening of the closing means, gain a curved shape. This can advantageously be achieved in two distinct ways : In a preferred embodiment, both edges of the opening side are fitted with semi-rigid strips, the semi-rigid strips are curved in their normal, relaxed state, and regain their original curved shape (i.e. they have a built-in "curved memory") upon opening of the closing means, so as to form an open mouth for the sachet.
In another embodiment, only one edge of the opening side can be fitted with semi-rigid strips, even if, preferably both edges are equipped with said strips; In this embodiment, the semi-rigid strips do not need to have a "curved memory" imparted to them, but a water-activated shrinkable fibre or thread,or elastic material, is positioned longitudinally accross the whole length of the opening side, in parallel with the semi-rigid strips, or strips, and is permanently fixed to the sachet at its extemities, so that upon opening of the closing means, the shrinkable fibre or thread,or elastic material shrinks, causing the semi-rigid strip or strips to gain a curved shape.
If only one edge carries a semi-rigid strip, the shrinkable fibre or thread can conveniently be positioned/attached along the edge which does not carry any semi-rigid strip.
If the shrinkable thread or fibre is water-activated, the action of water in the washing machine causes the thread or fibre to shrink. If the material is elastic, it is kept under stress by the closing means, and shrinks back to its relaxed dimension upon opening of the closing means.
"Semi-rigid" in the present context means that the strips, while not being completely rigid, have a sufficient rigidity to remain in the same curved state once the closing means are open; it is important indeed, that the open mouth formed by said rigid strips remains open throughout the washing cycle, to ensure optimum dispensing of the fabric-treatment product. If the rigidity of the strips is not sufficient, mechanical action in the washing machine could result in the strips being closed together, thus preventing further dispensing of the fabric-treatment product.
The strips can be produced from plastic, metal, laminates, water-resistant cardboard, wood, or any combination thereof.
To fulfill the needs of the present invention, there must be at least one semi-rigid strip permanently attached to each edge of at least one opening side, for the preferred execution herein or at least one edge of said opening side, for the alternative execution herein.
Preferably, only one strip is present on one edge of said opening side; in the preferred execution herein, a single pair of strips are thus positioned in such a way that they coincide with each other when said opening side is closed.
The semi-rigid strips can be of the same length as the opening side, and in this case, the strips are attached to each other at their extemities. In one execution, this is simply a bond between the very extremities of the strips.
In another execution, the strips are glued/bonded together at the portions nearing their extremities. In this case, the strips will need to be partially cut at the end of said portions, to create hinges, so as to ensure that the strips regain their original curved form, upon opening of the closing means.
The semi-rigid strips can also be of a length shorter than the length of the opening side; in this case, the semi-rigid strips are preferably not bonded to each other at their extremities, but it must be ensured that they are sufficiently firm at their ends, in order not to rotate about their long axis.
The semi-rigid strips can either be attached to the inside or to the outside of the edges of the opening side, preferably by heat-sealing, or possibly by other means such as water-insoluble hot melt glue.
It is a preferred execution of the invention that only one of the sides of the sachet be an opening side fitted with semi-rigid strips according to the invention. Said opening side is equipped with closing means which impose a constraint upon the semi-rigid strips, before use in a washing machine;
Said closing means contain preferably water-soluble seals, although mechanically-weak seals or combinations of water-soluble and mechanically-weak seals can be used.
In the most preferred execution the closing means is represented by an integral fold-over flap which can be sealed onto the sachet, preferably by means of a water-soluble adhesive.
Suitable water-soluble adhesives can, for example, be based on polysaccharides such as starch or dextrin, synthetic polymers such as polyvinyl alcohol, polyethylene oxide or alkali metal silicates. Small amounts of plasticisers, for example ethylene glycol, can be added to the water-soluble adhesives, if desired.
The present execution presents a processing advantage, since glue can be easily applied onto said flap, in line, during manufacture of the sachet, without the need for a separate coating step of the sachet.
In executions which do not contain the fold-over flap, the closing means is represented by a water-soluble adhesive applied directly to the edges of the opening side.
In another aspect of the present invention, more than one opening side is equipped with the semi-rigid strips and closing means described hereinabove.
Sides which are not equipped with semi-rigid strips may either be permanently sealed, and this represents the preferred execution of the invention, especially when the sachet contains only one opening side, or be additional opening sides, fitted with more conventional closing means like water-soluble seals.
Permanent seals are usually made by heat-sealing.
The flexible sheet materials which are used to form the sachets herein, can be made of paper, of woven, knitted or non-woven fabrics, or of plastic film material.
The materials should be water-insoluble and can be either water-permeable or water-impermeable.
The materials used to form the sachets are required to have a high wet strength, so as not to disintegrate during the washing process. The preferred sheet material for forming the bags is paper or thin non-woven fabric made out of synthetic fibres; synthetic fibres include fibres made out the following materials : polyethylene, polypropylene, polyester, polyamide, polyacrylate, cellulose acetate, polyacryloritrile, and any mixture thereof.
Alternatively, cellulosic materials can be used to make the non-woven fabrics herein, alone or in admixture with either synthetic or natural fibres. If natural fibres are used, it is desirable to include a proportion of long fibers such as manilla hemp, in order to improve the strength of the sheet material, and polymeric coating is also desirable for increasing wet strength.
It may be desirable to form the sachets of sheet material made from oxidation-resistant fibres, or to treat the sheet material before or after forming the sachets with a coating to improve oxidation resistance.
It water-insoluble, water-impermeable thermoplastic materials are used, including perforated materials such materials may advantageously be selected from polyolefins such as polyethylene, polypropylene, polystyrene; polyesters especially polyethylene terephthalate; vinyl polymers such as insoluble polyvinyl acetate and polyvinyl acrylate, polyvinyl chloride, and polyvinylidene chloride; polyamides and polyacrylonitrile; and other thermoplastic sheet materials having similar physical properties.
The fabric-treatment compositions which are contained in the sachets of the present invention are in particulate form, and are usually detergent compositions, i.e., a composition containing at least a surfactant and a builder is suitable for use in the present context; as an alternative, the sachets of the present invention can contain any particulate ingredient which is active during the wash and rinse cycles : bleaches, bleach activators, fabric softeners, perfumes, whitening or brightening agents, stain removal agents, enzymes and the like. It can be appropriate to keep certain of these ingredients separate during storage, and therefore executions of the present invention can be conceived, wherein the present sachets contain at least two different compartments; only one of the compartments may have an opening side with semi-rigid strips according to the invention, while other compartments have more conventional opening devices; another possible execution consists in multi-compartment sachet, most conveniently a two-compartment sachet, wherein all compartments have an opening side with semi-rigid strips according to the invention.
Certain embodiments of the invention hereinabove-described, will now be represented, by way of example only, by the accompanying drawings, in which :

Fig. 1a and 1b
represent a sachet with one single opening side, fitted with an integral fold-over flap (1) as closing means, in the closed (1a) and open (1b) positions; the semi-rigid strips (2) are seen in their curved state in the open position. Water-soluble adhesive (3), which seals the flap onto the sachet, is indicated on Fig. 1a.
Fig. 2a and 2b
represent a sachet with one single opening side, without fold-over flap, and where the closing means is represented by a water-soluble adhesive (3) applied along the edges of the opening side.
Closed (2a) and open (2b) position are represented, with the semi-rigid strips (2) in their constrained and relaxed state.
Figs. 3 and 4
represent part of a sachet in the open position wherein the semi-rigid strips (2) have the same length as the opening side; In Fig. 3 they are bonded together at their very extremities (4); In Fig. 4, they are bonded together at a certain portion nearing their extremities (6) and a partial pre-cut (7) is made in each strip, at the end of said portion, to allow the strips to spring open.
In both figures, a permanent heat seal (5) is represented.
Fig. 5 represents part of a sachet in the open position, wherein the semi-rigid strips (2) do not have the same length as the opening side, and are not bonded together.
In this execution, the permanent heat seal (8) which seals the side of the sachet goes all the way to the opening of the sachet and can even be reinforced in the part nearing the opening, so as to make sure that the strips (2) are sufficiently firm at their ends, to avoid that they rotate about their long axis.
Fig. 6a and 6b) illustrate the alternative embodiment of the present invention in which the semi-rigid strips (2) do not have a "curved memory", but an elastic or water-activated shrinkable thread (9) is positioned accross the opening side and fixed to the sachet at its extemities.
In Fig. 6a and 6b), one semi-rigid strip (2) is positioned on each edge of the opening side.
In Fig. 6a the opening side is closed by an integral fold-over flap (1) and glued onto a sachet by a water-soluble adhesive (3). The elastic or water-shrinkable material (9) is under stress and constrained between the two semi-rigid strips by the closing means.
In Fig. 6b the opening side is open and the elastic or water-shrinkable material (9) has shrunk to the dimension it has in its relaxed state, thus making the semi-rigid strips (2) gain a curved shape.
In Fig. 6c) only one edge of the opening side is fitted with a semi-rigid strip and the elastic (9) is positioned along the edge which does not have a semi-rigid strip.

EXAMPLE

A sachet according to a preferred embodiment of the present invention is made as follows :
A piece of nonwoven fabric consisting of polyester/polyethylene fibres, thermally bonded, calendered and hot embossed, is cut to desired dimensions, (see hereinbelow); strips of polypropylene material, which have been given a curved form by heating and quench cooling, are heat-sealed at the two smaller edges of the fabric, but at one edge a space is left to create the fold-over flap.
Strips are 110mm long, 15mm wide, and 1mm thick.
The fabric is then folded with the strips on the inside, and sides are heat-sealed. Dimensions of the sachet are 130mm x 99mm, and the created flap has a width of 17 mm.
Water-soluble glue is then applied onto the flap, and the sachet is filled with a particulate detergent composition, before being closed by folding-over the flap onto the sachet, the strips being brought in full contact with each other, then by sealing the flap onto the wall of the sachet, by means of a water-soluble adhesive (high molecular weight polyethylene oxide).
The particulate detergent composition used herein, has a density of 615g/l, and the formula is as follows :

Ingredients Percent by weight

Anionic surfactant 8.0%

Nonionic surfactant 5.0%

Sodium Tripolyphosphate 24.5%

Ingredients Percent by weight

Sodium Perborate Monohydrate 14.0%

Bleach Activator 4.0%

Enzyme 0.8%

Sodium Silicate 8.0%

Sodium Carbonate 11.0%

minors and water balance to 100
Several sachets are made according to the above method, and used as single-dose detergent articles in a washing machine.
At the end of the wash cycle, the opened sachets contain no, or a small amount, of residual detergent composition, and no loss of any spent sachet is observed within the washing machine.

Claims

1. A sachet of flexible sheet material with a fabric-treatment composition enclosed in it, for use as a single-dose fabric-treatment article, said sachet having at least one opening side fitted with closing means which open when the sachet is in use in a washing machine, characterised in, that along both edges of said opening side are permanently attached semi-rigid strips which are constrained in a straight position by the closing means, and which, upon opening of the closing means, gain a curved shape so as to form an open mouth for the dispensing of the fabric-treatment composition.

2. A sachet in accordance with claim 1, wherein the semi-rigid strips are curved in their normal relaxed state, and regain their original curved shape upon opening of the closing means.

3. A sachet in accordance with claim 1 wherein the closing means contains a water-soluble seal.

4. A sachet in accordance with claim 1 or 2 wherein the closing means contains an integral fold-over flap.

5. A sachet in accordance with claim 1, 2 and 3 wherein the closing means is a fold-over flap sealed onto the sachet in a water-soluble adhesive.

6. A sachet in accordance with claim 1 wherein only one semi-rigid strip is attached to each edge of said opening side.

7. A sachet in accordance with claim 1 wherein the semi-rigid strips are of the same length as the opening side, and are attached one to the other at their extemities.

8. A sachet in accordance with claim 6 wherein the poritions of the semi-rigid strips nearing their extremities are sealed together.

9. A sachet in accordance with claim 5 wherein the semi-rigid strips are of a length inferior to the length of the opening side.

10. A sachet in accordance with claim 1, which contains only one opening side.

11. A sachet in accordance with claim 1, which contains one opening side having the semi-rigid strips attached to its edges, and at least one other opening side.

12. A sachet in accordance with claim 10 wherein said other opening seal is closed by a water-soluble seal.

13. A sachet in accordance with claim 1 which contains two opening sides having the semi-rigid strips attached to their edges.

14. A sachet of flexible sheet material with a fabric-treatment composition enclosed in it, for use as a single-dose fabric-treatment article, said sachet having at least one opening side fitted with closing means which open when the sachet is in use in a washing machine, characterised in, that along at least one edge of said opening side are permanently attached one or more semi-rigid strips and that a water-activated shrinkable fibre or thread,or an elastic material kept under stress by the closing means, is positioned longitudinally accross the whole lenght of the opening side, in parallel with the semi-rigid strip or strips, and is permanently fixed to the sachet at its extremities, so that upon opening of the closing means, said shrinkable fibre or thread,or elastic material shrinks, causing the semi-rigid strip or strips to gain a curved shape.

15. A sachet in accordance with claim 14 wherein one semi-rigid strip is attached to each edge of said opening side.