EP0011501A1

EP0011501A1 - Particulate detergent composition contained within a closed bag of sheet material

Info

Publication number: EP0011501A1
Application number: EP79302601A
Authority: EP
Inventors: David Ellis Clarke; James Francis Davies; John Barry Tune
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1978-11-17
Filing date: 1979-11-16
Publication date: 1980-05-28
Also published as: JPS55500901A; ES486069A0; ES8101641A1; ZA796190B; WO1980001077A1; AU5292279A

Abstract

A detergent product comprises a water-permeable closed bag containing a particulate detergent composition with a bulk density of at least 0.5 g/cc. The bag material may be insoluble and formed from paper or plastics material sheet. The pore size distribution of the bag material is selected in relation to the particle size distribution of the detergent cbmposition to give less than 5% dusting. The bag may contain conventional detergent compositions and or other fabric treatment materials. The high bulk density powder enables the bag to be smaller with a saving in the bag material or to be less completely filled which gives better powder discharge in the wash.

Description

TECHNICAL FIELD

The invention relates to detergent products which are suitable for treating fabrics in a washing machine and which contain detergent compositions in particulate form.

BACKGROUND ART

Although the marketing of particulate detergent compositions packaged in cartons is common practice, this imposes constraints both on their formulation and methods of production. For example the compositions must be free flowing and have an attractive appearance to the consumer, and the ingredients should not segregate during transport and storage. The products must also be safe, both for contact with the skin and in the event of accidental ingestion; in particular, the compositions should not contain too high a level of alkaline materials, although alkalinity is beneficial for detergent properties.
When using'washing machines which have a rotating drum in which the fabrics are placed, there can also be substantial losses of conventionally dosed detergent powder by retention in the dispenser and by its accumulation in the dead spaces beneath the drum, such as the drain hose.
It has been proposed previously to market powdered detergent compositions in packages, each of which contain a suitable amount of a detergent-powder for an individual wash under standard washing conditions. In particular, the detergent powders can be contained within bags of water permeable or water-soluble materials, such as polyvinylalcohol, but such packages have not yet met with much commercial success. One of the reasons for this is believed to be the higher cost of packaging the detergent powders in this way which has outweighed the increased convenience in using the products.

DISCLOSURE OF THE INVENTION

We have now found that improved products of this type can be made by substantially increasing the bulk density of the detergent compositions used, which decreases the packaging costs and may also enable cheaper production methods to be used.
According to the present invention a detergent product comprises a particulate detergent composition, the bulk density of which is at least 0.5 g/cc, contained within a closed water-permeable bag. The bag may be formed of natural or synthetic, woven or non-woven materials, which preferably are water-insoluble. While the preferred detergent composition is a fully formulated detergent composition, it may be constituted by any other fabric treatment material. As the conventional spray dried detergent compositions which have been proposed for. inclusion within bags before have bulk densities of the order of 0.3 to 0.4 g/cc, there can be a significant reduction in the size of the detergent bags whilst still containing enough weight of the detergent composition in each bag for effective fabric washing. By using a detergent composition of high bulk density, the same weight of detergent composition can be contained in the same size bag, while enabling the bag to be less tightly filled.
An alternative or additional advantage of filling the bag less tightly is that a greater rate of release of powder into the washing machine may be achieved.
In addition, the use of a higher bulk density for the detergent compositions, enables one to avoid the traditional spray drying process which gives the powders of lower bulk density. The other processes which'can be adopted for making the particulate detergent compositions for inclusion in the product of the present invention, for example granulation and dry mixing processes, cannot readily be used for making detergent compositions sold in bulk powder form because such compositions generally do not look so attractive as the spray dried powders.
A further advantage which may be mentioned for the products of the invention is that the detergent compositions can be more highly alkaline, because of their protection from close contact with the skin by the bags, which .leads to improved performance. Additionally, the loss of detergent powders when conventionally dosed, either by residues in the dispensing device or by accumulation of undissolved powder in the dead spaces at the bottom of washing machines, is avoided, so leading to better washing performance without overdosing the powders.

BEST MODE OF CARRYING OUT THE INVENTION

The bags used to contain the detergent composition in the products of the invention may be constructed of paper or of woven, knitted or non-woven material or plastics sheet material. Any such sheet material used must be water-permeable and preferably water-insoluble. The pore size should be such that there is no excessive dusting of the detergent composition through the material of the bags in the dry state but yet that water can pass readily through the material forming'the bags to disperse and dissolve the contents when the product is used.
A suitable sheet material for foming the bags is water-permeable paper or non-woven fabric of high wet strength, weighing about 5 to 100, preferably 10 to 6₀ g/m², especially about 15 to 40 g/m², such as is commonly used for packaging beverage powders and other foodstuffs, and suitable sheet materials of this type are commercially available, for example from J R Crompton Bros Limited of Bury, England. The fibres preferably used for. the sheet materials may be of natural or synthetic origin and may be used alone or in admixture, for example polyamide, polyester, polyacrylic, cellulose acetate, polyethylene, polypropylene, PVC, PVdC (polyvinylidene chloride) or cellulosic fibres. If some cellulose pulp fibres are used, it may be desirable to include a proportion of long fibres such as Manila hemp, in order to improve the strength of the sheet material and pliability, and reducing stiffness, thereby giving the material a fabric-like appearance, and a binder may also be necessary for increasing wet strength. It is preferred to include at least a proportion of thermoplastic fibres, for example polypropylene fibres for increasing resistance to chemical attack by any of the ingredients of the detergent compositions.
The preferred bags are made with cellulosic fibres treated with a heat-sealing agent, or from mixtures of cellulosic fibres with thermoplastic fibres.
If desired, the sheet material of the bags may be treated with a protective agent to increase its resistance to chemical attack by the detergent composition, for example by coating the sheet material with a water-soluble substance, e.g. a water-soluble cationic detergent active material or soap, or by providing an extra protective layer of a water-soluble sheet material such as a soluble polyvinyl alcohol. Alternatively, the sheet material of the bag may be treated with a removable water-insoluble protective agent such as a silicone , a fatty acid, a water-insoluble cationic softening agent, wax or clay. Some of these treatments' e.g. clay, may tend to inhibit dusting, so sheet materials-with somewhat larger maximum pore sizes can be used, which facilitates the rapid dissolution of the detergent composition in water. If the bags are to be used for detergent powder which contains a bleaching agent, for example sodium perborate or sodium percarbonate, it is desirable to treat the sheet material before or after forming the bags with a coating to improve oxidation resistance, or to form the bags of sheet material made from oxidation-resistant fibres.
The bags can be formed from a single folded sheet formed into a tubular section, or from two sheets of the material bonded together at the edges. For example, the bags can be sachets formed from single folded sheets and sealed on three sides or from two sheets sealed on four sides for the preferred rectangular shape. Alternatively, the sheets can be folded like envelopes with overlapping flaps to be sealed. Production of the bags by heat-sealing, cold pressure sealing or by the use of water-soluble or water-insoluble adhesives is possible, heat-sealing or cold pressure-sealing being preferred as this can be done rapidly and hence more economically, compared with the use of adhesive sealing.
The bag may be constructed to open under the influence of mechanical action during use, such as by bursting of a weak seam, the disintegration of the bag material or the bursting of the bag along a perforation line. Alternatively, the bag material may be sufficiently porous so that water can readily pass through the bag material to disperse and dissolve the contents when the product is used.
Any detergent composition in particulate form can be packaged to advantage in the products of the invention, provided it has a bulk density of at least about 0.5 g/cc. As an alternative to fully formulated detergent compositions .(that is a composition containing at least a surfactant and a builder), the bags may contain any one or more of the following fabric treatment materials: bleaches such as sodium perborate; bleach precursors such as tetraacetyl- ethylene diamine (TAED); fabric softeners such as quaternary ammonium compounds; starch; perfumes; anti-bacterial agents; stain removing agents and the like. It can be of particular advantage to add fabric treatment materials to the wash in a bag while dosing a fully formulated detergent composition in a conventional manner, where the incorporation of the fabric treatment material in the fully formulated detergent composition may otherwise be difficult. This is of particular importance in the case of perfumes, bleaches, bleach precursors and cationic fabric softening agents.
The fully formulated compositions which can be packaged to advantage in the products of the invention are amply described in the literature, for example in "Surface Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.
However, the products of the invention are advantageously used for detergent powders containing insoluble ingredients. Specific examples of such ingredients include finely divided calcium carbonate,'the use of which is described in UK patent No. 1 437 950, and sodium aluminosilicate ion-exchange materials as described in UK patent specifications Nos.1 429 143, 1 473 201 and 1 473 202.
It is also advantageous to use the products of this invention with detergent compositions containing bleach systems, particularly containing TAED and sodium perborate.
To achieve the maximum potential benefit of decreased packaging and transport costs the bulk density should be as high as practicable, preferably about 0.6 to 0.8 g/cc. Higher bulk densities, particularly about 1 g/cc, are less advantageous as this can only normally be achieved with a reduction in the rate of water-solubility or dispersibility. The particle size distribution of the detergent composition should preferably be selected in relation to the pore sizedistribution of the bag material so that no more than about 5% by weight,preferably no more than about 1%, of the particles can pass through the sheet material.,and hence cause dusting. Bags for very fine powder, for example, made by dry mixing,should preferably be made from sheet material having a very small maximum pore size so as to allow only detergent particles less than about 20 microns to dust from the bag on handling or in transit. Bags for coarser grained detergent compositions, should preferably be made from sheet material having a maximum pore size so as to allow only detergent particles less than about 100 microns to dust from the bag. The bag material should,however,be such as to allow water to pass through and also particles of about 10 microns and smaller. To meet this requirement a bag material weight of less than about-60 g/m² should be used. It may be noted that larger pore sizes are generally better for dissolving powder quickly, but this puts more constraints on the powder processing techniques which may be used in order to avoid excessive dusting. In a particular embodiment of the invention, the bag material has a pore size distribution which includes less than 20% by area, preferably less than about 10% of pores having a pore size above 100 microns.
Papers and non-woven fabrics having a pore size distribution with less than 20% pores having a size over 100 microns include Manila hemp treated with a viscose wet strength agent, such as is used for sausage casings, Meraklon 2126 and 2136 (polypropylene fabric available from Monte Edison (UK) Limited, Manchester, England) and Viscose PHm 25 (available from Bonded Fibre Fabrics Limited, Bridgwater, England).
In the case of detergent compositions which are slow to dissolve or disperse, the bag may be filled with less than 50% of the maximum amount of detergent composition which the bag could contain, more preferably between about 5% and about 20% of the maximum amount of detergent composition which the bag could contain. In the case of other detergent compositions, a filling of more than 50% may be economically advantageous.
If desired, the bags can be formed with more than one separate compartment containing different detergent ingredients, at least one of which ingredients has a bulk density above 0.5 g/cc, or the bags may be formed in a conjoined manner, for example in a strip to facilitate dosing of different numbers of the bags as appropriate for the wash conditions. The use of multi-compartment bags facilitates the use of detergent ingredients which would otherwise interact with other ingredients in detergent compositions, whilst avoiding encapsulation or other treatment to prevent contact between such ingredients in a single composition.
For example, one compartment may contain a fully formulated detergent free of bleach while a second compartment may contain the bleach. A third compartment may contain a fabric softener. Other bag shapes or constructions, for example circular cushion shaped sachets or of tetrahedron form, may be used if desired. The bags may also be reinforced, if desired, to decrease the risk of leakage during handling, for example by adding an extra thickness of the sheet material where the bags are expected to be held or passing completely round the bags to help support the weight of detergent powder.
If desired, the sheet material used to form the bag can be marked or tagged so that it can be easily recognised amongst the washed fabrics, for example the material may be printed with a simulated fabric pattern such as check or gingham. It can then either be discarded, or if desired, it may be constructed of a suitable material to provide it with a secondary use, for example as a cleaning cloth.
The invention is illustrated by reference to the following Examples in which parts and percentages are by weight except where otherwise indicated.

EXAMPLE 1

Detergent bags in sachet form were made from a non-woven thermoplastic.sheet material constructed from polypropylene fibres, and weighing 20 grams per m². Pieces of the sheet material measuring approximately 9" x 4½" (22.5 cm x 11.25 cm) were folded in half and then heat-sealed along two opposing edges. The open bags so formed were each filled with 84g of detergent powder of high bulk density (0.68 g/cc) prepared by a granulation process as described in Belgian patent No. 867 038 (United States application S/N 905 681) to the formulation below and then heat-sealed along the open edge to form sachets (4½" x 4½").
It was found that the filled bags did not burst during handling although full of detergent powder, and there was very little dusting through the non-woven material used. On using the sachets in a front loading automatic washing machine (Hoover Electronic 800), by placing the sachets with the clothes inside the drum,then washing the clothes under the high temperature wash cycle, the bags were found to discharge their contents rapidly through the pores of the material on coming into contact with the water, and to give a satisfactory wash.
The following Example demonstrates the dependence of the rate of release of powder into the washing machine on the dimensions of the sealed bag.

EXAMPLE 2

Three bags of various sizes were formed from a non-woven polypropylene material having a weight of 30 g/m^2. 80 g of the detergent composition used in Example 1 were placed in each bag which was then heat-sealed. A clean load of mixed fabrics were placed in the drum of a Hoover Electronic 1100 machine. The bags were placed side by side on top of the load and after the intake of cold water, agitation was allowed for 2 minutes. The bags were removed from the machine, excess water blotted off and dried. The dried powder was removed and weighed. The results are given in the following table which also includes the maximum weight of the same detergent compositions which bags of these sizes could hold.
The results show that the larger the bag the greater the release of powder.

EXAMPLE 3

The following Example demonstrates the benefit of a high density powder in a non-opening bag over the same powder dosed conventionally. The bag material was spunbonded, continuous filament non-woven polypropylene, having a weight of 20 g/m², obtained from Lutrasil Ltd, Halifax, England. The bags were formed by heat-sealing and contained 48 g of a ternary active, STP built powder with a bulk density of 0.6 g/cc. Each bag was placed through door-of a Miele 429 automatic washing machine together with a soiled load and halved soiled articles. The washing conditions were 0.3% concentration in 24°H water (22.4° CA, 1.5° Mg). The 40°C cycle was used. Out of 18 halved soiled articles 9 showed that the detergent composition in a bag gave better cleaning, 1 showed that conventional dosing via the dispenser of the machine gave better cleaning and 8 showed no difference.

Claims

1. A detergent product comprising a closed water-permeable bag containing a particulate detergent composition, characterised in that the particulate detergent composition has a bulk density of at least about 0.5 g/cc.

2. A detergent product according to Claim 1, characterised in that the closed water-permeable bag is formed of a water-insoluble material.

3. A detergent product according to Claim 1, characterised in that that material of which the closed water-permeable bag is formed is coated with a water-soluble or removable water-insoluble agent to reduce dusting.

4. A detergent product according to Claim 1, characterised in that the bag is closed by seals formed by heat-sealing or cold pressure sealing.

5. A detergent product according to Claim 1, characterised in that the particulate detergent has a bulk density of from' about 0.6 to about 0.8 g/cc.

6. A detergent product according to Claim 1, characterised in that the detergent composition is selected from fully formulated detergent compositions, bleaches, bleach precursors., fabric softeners, starch, perfumes, anti-bacterial agents, anti-static agents, whitening agents, blueing agents, stain removing agents and mixtures thereof.

7. A detergent product according to Claim 1, characterised in that the material of which the closed water-permeable bag is formed has a porosity which is such in relation to the particle size distribution of the particulate detergent composition that no more than about 5% of the particulate detergent composition can pass through the material.

8. A detergent product according to Claim 7, characterised in that no more than about 1% of the particulate detergent composition can pass through the material.

9. A detergent product according to Claim 1, characterised in that the amount of particulate detergent composition contained in the closed water-permeable bag is less than 50% of the maximum amount of such detergent which the bag could contain.

10. A detergent product according to Claim 1, characterised in that the bag includes at least two compartments containing different detergent ingredients, at least one of said

11. A detergent product acording to Claim 1, characterised in that the pore size of the bag material is sufficient to allow water and also particles of about 10 microns and smaller to pass through and in that the bag material has a weight of less than 6₀ g/_m ².