WO2001059057A1

WO2001059057A1 - Detergent composition in tablet form

Info

Publication number: WO2001059057A1
Application number: PCT/GB2001/000513
Authority: WO
Inventors: Paul Robinson; Guido Waeschenbach; Brendan Collins; Ralf Wiedemann; Enric Carbonell; Richard Neergaard
Original assignee: Reckitt Benckiser N.V.
Priority date: 2000-02-09
Filing date: 2001-02-09
Publication date: 2001-08-16
Also published as: GB0103251D0; AU2001232038A1; DE10005576A1; GB2361242A

Abstract

A detergent composition in tablet form, wherein the formulation and/or the method of manufacturing the tablets are/is selected such that the tablets experience sufficient buoyancy upon contact with a water reservoir that they at least remain suspended in the water.

Description

Detergent composition in tablet form

The present invention relates to a detergent composition in tablet form and its uses.

Detergent compositions, such as detergents for dishwashing machines and for laundry washing machines are nowadays available in three different presentations.

The traditional presentation, which is still the most common even today in laundry detergents for example, consists of powder or granules in which the average particle size ranges between 0.1 and 2 mm in diameter. It is standard for powder or granules, both in a dishwasher and in a washing machine, to be washed out of an appropriate chamber by water, the chamber opening during the washing cycle. Because of the hygroscopic nature of the powder or granules, lumps occasionally form, as a result of which the amount of detergent used may be too small. Certain ingredients have therefore been added, such as paraffin, which are intended to prevent the formation of such lumps, though this cannot always be relied on to be successful in every case.

A second presentation is liquid detergents, though their cleaning power does not match that of conventional powders or granules.

For some years now, detergents in tablet form have been available on the market and, in the case of dishwasher detergents for example, they have in the meantime actually overtaken the other types. These tablets are usually manufactured from the same ingredients as the known powders or granules, sometimes with the addition of tabletting aids. The problems with the formation of lumps which were known from powders and granules cannot occur with these tablets, which usually contain the full amount needed for one washing cycle, so that, in each case, only one tablet needs to be used for each washing cycle. Furthermore, the use of detergent tablets avoids the need to measure out powder or granules, which can sometimes be complicated and tiresome.

One disadvantage of conventional detergent tablets consists in the fact that they rapidly sink to the bottom of the water reservoir at the base of the machine, and it can happen that, depending on the circumstances, they will only dissolve slowly, so that they cannot develop their full effect. In principle, this risk is also present in other uses, such as the dissolution of descaling tablets in coffee machines, for example, or the dissolution of a detergent tablet for hand-washing laundry.

In the case of washing in a washing machine, i.e. especially with detergent or water softener tablets, there is the additional risk of direct and intensive contact between the tablet and the laundry, which can lead to undesirable colour transfer or fabric damage.

The invention is therefore based on the problem of overcoming the disadvantages in the state of the art described, and especially the disadvantages of conventional detergent tablets. In accordance with the invention, this problem is solved in a detergent composition in tablet form in that the formulation and/or the method of manufacturing the tablets are selected such that the tablets experience sufficient buoyancy upon contact with a water reservoir that they at least remain suspended in the water.

In a preferred embodiment of the invention, there is provided a detergent composition in tablet form wherein the formulation of the tablets is selected such that the tablets experience sufficient buoyancy upon contact with water that they at least remain suspended in the water.

It is preferably envisaged that the tablets should float to the surface upon contact with a water reservoir.

In an alternative embodiment, the invention proposes that the tablets should include an effervescent system in a sufficient quantity.

In a further alternative embodiment, the invention proposes that the density of the tablets should not be substantially greater than 1. Preferably the density of the tablets is approximately 1 or less than 1.

Each individual tablet should preferably weigh between 5 and 700 mg. Preferably each tablet weighs less than 600mg, more preferably less than 400mg and most preferably less than 250mg. Preferably each tablet weighs more than lOmg, more preferably more than 20 mg and most preferably more than 40mg. In a preferred embodiment of the invention, each individual tablet weighs between 50 and 150 mg.

The invention further comprises a method of manufacture of a detergent composition including the step of forming the detergent composition in a tablet form such that the tablets experience sufficient buoyancy upon contact with water that they at least remain suspended in the water.

In a preferred embodiment of this aspect to the present invention, the detergent composition is formed in a tablet form such that the density of the tablets is not substantially greater than 1. Preferably the density of the tablets is approximately 1 or less than 1.

The bouyancy and/or density of the tablets according to the present invention can be manipulated in a variety of ways.

Normal tablet compression leading to an acceptable robustness of tablet is in the order of 10 tons which results in a tablet density of 1.2 to 1.5. As such, the compression value may be reduced in the tabletting step to result in a tablet that has the bouyancy/density required but still exhibits an acceptable robustness.

Alternatively, the tablets could be compressed about a central body of much reduced density, for example cork, or an air space.

The tablet formulation may initially include a volatile solvent which evaporates off after compression to result in a table of lower density. The detergent composition of the invention can be used in a variety of ways in appropriate quantities, e.g. as a dishwasher detergent, in the final rinse in a dishwasher, as a detergent in a washing machine, as a detergent for hand-washing laundry, as a water softener or fabric conditioner in a washing machine, as a bleach enhancer in a washing machine or dishwasher, or as a descaling agent. It goes without saying that other possible uses are conceivable and are also encompassed.

The composition of the invention solves the problems of conventional detergent tablets, which were mentioned at the beginning, in a surprisingly simple and effective manner.

Since it is proposed, in accordance with the invention, that the tablets should be formulated and/or manufactured such that they experience sufficient buoyancy that they at least remain suspended in the water, and in a specific embodiment even float on the surface of the water, it is ensured firstly that the tablets do not sink to the bottom or into the sump of the wash liquor, and secondly

(when used to clean laundry) that they do not enter direct and intensive contact with the items of laundry.

The detergent composition in tablet form of the invention is particularly effective if an effervescent system is provided, such as a combination of bicarbonate of soda and citric acid, since the effervescent effect first of all means that the tablets develop the desired buoyancy, and secondly it supports the rapid dissolution of the tablets. If the density of the tablets is set not substantially greater than 1, this likewise achieves the most important effect, namely that the tablets obtain the desired buoyancy, but there is no more rapid dissolution in the water, as there is with an effervescent system. Nevertheless, this alternative is also advantageous compared to conventional detergent tablets.

The teaching of the invention can be implemented particularly effectively with tablets weighing between 5 and 700 mg, and, in an especially preferred embodiment, between 50 and 150 mg, because these tablets are light enough to obtain the necessary buoyancy in any case as a result of the measures proposed in accordance with the invention. The tablets can have various shapes, such as spherical, cylindrical, ellipsoid, etc. In the case of a spherical design, the preferred diameter is between 2 mm and 10 mm.

The detergent compositions of the present invention can be manufactured using a variety of processes. By way of example, we could mention normal pressing under pressure. It goes without saying that it should be ensured that the pressure is not too high, because, if the tablets are too dense, and especially if they are relatively heavy, this might mean that the tablet cannot obtain sufficient buoyancy even if an effervescent system is provided.

A further preferred manufacturing process is compacting, which is understood in this application to mean pressing agglomeration without the use of binders, which is usually performed by rollers rotating in opposite directions and possessing grooves of the appropriate dimensions. With this production process, it is also possible to use other ingredients, which are usually not suitable for pressing, because the pressures during compacting are considerably lower, or densities can be achieved which cannot be reached with conventional pressing, because the pressures are considerably lower in compacting.

Before turning to a detailed description of the composition of the invention, it should first of all be pointed out that the term "detergent composition" and "detergent" are understood in a broad sense in the present application, namely as comprising all those substances and mixtures of substances which can be used in connection with cleaning processes. These include not only the compositions which are actually active in cleaning, such as dishwasher detergents and washing substances, but also compositions which support the cleaning functions concerned, such as water softeners, or which have the effect of providing protective care, such as fabric softeners or final rinses.

The starting material for the detergent compositions of the invention in tablet form can be formulated in the same way as conventional powders, granules or tablets. A suitable formulation can therefore comprise a large number of different ingredients, including builders, surfactants, enzymes, bleaches, bleach activators, sources of alkalinity, dyes, perfumes, dispersants for lime soaps, organic polymers, including polymers to inhibit colour transfer, crystal growth inhibitors, complexing agents for heavy metal ions, salts, enzyme stabilisers, corrosion inhibitors, solvents, fabric softeners, optical brighteners, hydrotropic agents, etc. In addition, the compositions can contain suitable fillers, such as sulphates and carbonates, and tabletting aids, such as polyethylene glycol, starch or starch derivatives, etc.

The tablets can be provided with a water soluble coating, the nature of that coating being determined by the purpose for which it is intended. Any water-soluble polymer can be provided for a coating, for example, if the purpose of the coating is to provide greater stability during storage and handling and/or a certain delay in dissolution in the wash liquor. If the aim of the delay is, for example, for the ingredients to be released in a certain phase of the washing cycle, as is the case with formulations for the final rinse for machine rinsing in the form of the invention, pH- dependent coating materials can be used, such as those described in DE 198 34 180.6 (which is not pre- published) .

The detergent composition of the invention can be used in a variety of ways. By way of example, we may refer to use as a dishwasher detergent, as a final rinse in dishwashers, as a detergent in a washing machine or for a hand wash, as a water softener or fabric softening rinse in a washing machine, or as a descaling agent. Other fields of use in the detergent sector are conceivable and possible, such as use as a detergent composition for dissolution in water, for cleaning hard surfaces, such as floors.

The features of the invention disclosed in the above description and in the claims can be essential, both alone and in any combination, for carrying out the invention in its various embodiments.

The invention will now be described with reference to the following examples.

Example 1

Water Softening Tablets

Equipment used: Roller compactor

Single layer and double laye {divided hopper) briquettes were produced Size of tablettinos: Weight=100mg

Water softener tab formuila

Ingredients Total White Layer Blue Layer citrate 56.120 52.730 62.890 polymer 22.770 22.770 22.770

PEG 6000 3.000 3.000 3.000 cellulose 4.500 4.500 4.500 cellulose 2.500 2.500 2.500 sulfate 8.350 12.520 0.000 silicate 0.660 2.000

Dye 0.005 0.016

PEG 200 0.115 0.344

Water 1.980 1.980 1.980 Total 100.000 100.000 100.000

Manufacturing Instructions:

White Powder Mixture

Add the raw materials to the Lodige Mixer in the above order while the mixer works at 20% speed. Mix for 30 seconds with mixer at 50% speed and check versus specification. Protect from heat and humidity.

Blue Powder Mixture:

Add raw materials 1 to 6 to the Ruberg Mixer in the above order while mixing at 50% speed.

Spray on the colour pre mix over 1 minute while continuing to mix.

Remove the fuel injector, after then mix for 3 minutes at 50% speed. The colour should appear homogeneous.

Check the specifications data and fill in two big bags, close and protect against heat and humidity. Process the mix within 4 weeks max.

Colour Pre Mix

Polyethylene Glycol 200 95.667 dye 4.333 Mixer must be dry. Add the ingredients. Mix for 5 minutes. The liquid should appear homogeneous. Store in closed containers.

The tablets were each formed around a sized piece of cork such that the final density of each tablet was in the region of 0.8 to 1.0.

Example 2 Equipment used: Roller compactor

Double layer (divided hopper) tablettinos were produced Size of tablettinos: Lenght=9 mm Width=6 mm Thickness=4, 35 mm Weight=0,27 gr

Formula : DOUBLE LAYER BRIQUETTES (%

- Layers NaCl Organic acid Carbonate PEG 6000 Dye White 96 1 1 2 Blue 90.725 7.2 2 0.075

White 96 Blue 90.7 7.2 0,1 White 96 2

Blue 90.775 7.2 2 0.025

White 96 Blue 90.76 7.2 2 0,04

White 96 Blue 90.79 7.2 2 0.01

White 96 1 2 Blue 90.75 7.2 2 0.05

The organic acid used was citric acid and the carbonate was calcium carbonate.

The effervescent couple included in the white layer of each tablet resulted in the combined tablets floating or being bouyant in an aqueous environment.

Claims

1. A detergent composition in tablet form, characterised in that the formulation and/or the method of manufacturing the tablets are/is selected such that the tablets experience sufficient buoyancy upon contact with a water reservoir that they at least remain suspended in the water.

2. A detergent composition as claimed in Claim 1, characterised in that the tablets float to the surface upon contact with a water reservoir.

3. A detergent composition as claimed in either of Claims 1 or 2, characterised in that the tablets include an effervescent system in an appropriate quantity.

4. A detergent composition as claimed in either of Claims 1 or 2, characterised in that the density of the tablets is not substantially greater than 1.

5. A detergent composition as claimed in any of Claims 1 to 4, characterised in that each individual tablet weighs between 5 and 700 mg.

6. A detergent composition as claimed in Claim 5, characterised in that each individual tablet weighs between 50 and 150 mg.

7. Use of a detergent composition as claimed in any of the preceding claims in an appropriate dosage as a dishwasher detergent.

8. Use of a detergent composition as claimed in any of Claims 1 to 6 in an appropriate dosage as a final rinse in a dishwasher.

9. Use of a detergent composition as claimed in any of Claims 1 to 6, in an appropriate dosage as a laundry detergent in a washing machine.

10. Use of a composition as claimed in any of Claims 1 to 6, in an appropriate dosage as a detergent for hand-washing laundry.

11. Use of a detergent composition as claimed in any of Claims 1 to 6 in an appropriate dosage as a water softener in a washing machine.

12. Use of a detergent composition as claimed in any of Claims 1 to 6, in an appropriate dosage as a fabric conditioner in a washing machine.

13. Use in a detergent composition as claimed in any of Claims 1 to 6 in an appropriate dosage as a bleach enhancer in a washing machine or dishwasher.

14. Use in a detergent composition as claimed in any of Claims 1 to 6 in an appropriate dosage as a descaling agent.