EP0096680A1 - Detergent composition - Google Patents

Abstract

Detergent preparation containing sodium carboxymethylcellulose (CMC) having a viscosity comprised between 15000 and 25000 m Pas, measured at 22<o>C and in the form of a 2 % solution, on the basis of 5 to 25 %, the rest being comprised of usual ingredients of a detergent composition, in other words washing adjuvants and surface active agents. The product is conveniently prepared in the form of tablets of 2:4 to 2:5 g obtained by compressing the starting powder to reduce its volume by half under a pressure lower than 1 kg/cm<2>.

Description

The present invention relates to a detergent preparation which can be used for various purposes, in particular for use in washing machines. The invention will be described essentially below with reference to the use in a washing machine, but it should be understood that the invention also applies to detergent preparations used in dishwashers and also for washing says "by hand".

Detergent preparations are generally presented in two main forms, namely "washing powders" or "liquid detergents".

Washing powders are most commonly reserved for use in washing machines; liquid preparations which are generally concentrated detergents in solution in water are used less frequently for washing machines and are more generally reserved for so-called "hand washing", for washing dishes, whether machine or hand, etc.

These two presentations of detergents are linked to a series of drawbacks.

Both present in common the fact that they are generally used in a quantity greater than the quantity required, owing to the exact difficulties of measuring the quantity used. These two forms of presentation of detergents also give rise to certain precise dosing difficulties, in particular when it is desired to introduce a reserve for several washes in a machine beforehand, by providing that the machine will automatically take the quantity of detergent required for each type of operation.

A particular drawback associated with the use of powders is the difficulty in preventing segregation of the constituents of different specific weight when the powder is subjected in particular to vibrations during transport, storage, etc. To overcome this drawback, a lot of research has been done to give the different ingredients of the powder the same apparent specific weight.

Thus, in particular, an attempt has been made to modify the specific weight of the peroxidized compounds, in particular sodium perborate in order to avoid segregation of the latter in the packaging of washing powders.

It should also be noted that some people are allergic to powders, which causes difficulties both for the workers responsible for packaging in the factory and for the housewife using the products.

Many other drawbacks could be cited both for powders and for liquid preparations, such as the high specific volume, the difficulties of handling and packaging, the low biodegradability, etc.

Various proposals have therefore been made to package the detergent preparations in another form.

Thus, US Pat. No. 4,234,442 describes a packaging of a detergent composition in sachets which decompose in water. This packaging requires bagging that is not very compatible with industrial production rates and does not allow automation.

US-A-4,219,435 describes a detergent composition coated with hydrated salt. This also makes it necessary to have recourse to a particular production technique and to drying which is not very compatible with modern production techniques.

US-A-4,099,912 describes, among other things, a washing process comprising the use of a tablet, but the composition formulations mentioned do not make it possible to obtain a composition which is sufficiently coherent in the compressed state and which decomposes easily on contact with the water.

The present invention therefore aims to obtain a detergent preparation which contains a suitable agent which facilitates compaction to form a tablet, this agent in combination with the detergent constituents of the composition also exerting a synergistic effect with said detergents to increase the washing properties. and of detergency and ultimately facilitating the disintegration of the tablet.

It appeared that sodium carboxymethylcellulose (CMC) having a viscosity of the order of 15,000 to 25,000 m Pas, and preferably of the order of 20,000 m Pas measured at 20 ° _C and in the form of a 2% by weight aqueous solution meets this criterion when it is contained in the detergent composition in an amount of 5 to 25%, preferably in an amount of about 15% by weight.

The present invention relates equally to such a preparation in the form of powders as in the form of tablets.

The conventional detergent constituents can be used for this purpose, such as those mentioned in the state of the art, mentioned above which is included in the present specification for reference but preference is given to sodium lauryl and sodium sulfate at the right rate. at least 35% and preferably about 45% by weight of the total composition with other surfactants and any adjuvants.

Advantageously, according to the invention, the preparation is obtained starting from a conventional detergent composition in compressed powder in the presence of the above-mentioned CMC by carrying out a compression such that, starting from conventional powders, tablets are formed. Advantageously, the compression is performed such that at the start of the powder preparation is compressed in a pastil _- Leuse vector volume "powder to reduce at least by half.

The Applicant has observed, in fact, that the conventional techniques for producing lozenges or tablets, as used in the pharmaceutical industry, generally do not give adequate products.

Indeed, conventional techniques provide for the use of very high pressures of the order of several bars, which results in the formation of pellets difficult to break and especially dissolving very slowly in water.

In practice, it has been observed that if a tablet production machine is filled so as to contain 16 mm of material, it is necessary to compress at least so as to reduce the height of the tablet to 8 mm and advantageously to a value of the order 7.5 mm to obtain an adequate product.

The nature of the CMC, in particular the viscosity indicated, is of great importance for achieving the objectives of the invention. The main characteristic of this binder is that it must be soluble in water and also swell in water to facilitate the disintegration and dissolution of the tablet.

Advantageously, the products generally incorporated in detergent preparations can also be present in the composition of the invention. It is known that the various constituents added to detergent preparations vary depending on the use for which the preparation is intended. By way of example, in addition to the surface-active materials, the usual additives can be incorporated into the preparation such as whitening products, "builders", agents acting as foam limiters or stabilizers, optical bleaching agents, perfumes, various additives, in particular softeners or anti-scale agents, anti-redeposition agents, enzymes, etc.

The preparations of the invention generally do not contain sodium polyphosphates although their use can in some cases be envisaged. Generally, their presence is undesirable due to the effect of eutrophication of water caused by its discharge into the water. runoff water.

It should be noted that the use as a binding agent of the sodium salt of carboxymethylcellulose has an additional advantage resulting from the detergent action. specificity of this product and its synergy with other surfactants. In addition, as is known, this product acts as an anti-redeposition.

In practice, the conditions for obtaining the tablets are such that the pressures used are less than 1 kg / cm ² , the pressures preferably being of the order of 0.6 kg / cm ² .

The invention will be described in more detail with reference to the following description of a preferred embodiment of the invention.

It should however be noted that, in the present specification, the term "tablet" or "pellet" applies to a product which has undergone a compacting action so as to agglomerate the constituent particles together under the action of the CMC. The terms "tablet" and "lozenge", however, do not necessarily have to be understood in the strict sense given to them in the pharmaceutical industry or in other fields, the main point being the presence of the binder and a certain cohesive effect. .

The following table relates to a typical composition of a washing product for a washing machine which is suitable for preparation in tablet form. It should be noted that the preparation essentially relates to a preparation intended for washing white linen in washing machines, because it contains enzymes and sodium perborate. Those skilled in the art can however easily adapt the detergent preparation, in particular by purely and simply resorting to conventional commercial preparations according to the various desired uses.

Examples

A mixture was prepared containing the following constituents:

The powder mixture thus prepared is introduced into a tablet press under a filling height of 16 mm and various tests have been carried out by applying variable manufacturing pressures which result in variable heights of compressed tablets. The weight of the tablet corresponding to the filling height of 16 mm, for said constituents is 3.5 g, the diameter of the cylindrical tablet being 21.9 mm.

Under a pressure of 3 kg / cm ² , a pellet with a thickness of 6 mm is also obtained which is also very hard and the dissolution of which is negligible also after 1 hour.

Under a pressure of 2 kg / cm ² , the pressure is 6.5 mm, the product is hard to break and the dissolution is still very weak after 1 hour.

Under a pressure of 1 kg / cm ² , the thickness of the pellet is 6.9 mm, it is less hard to break but the dissolution is still unsatisfactory.

Under a pressure of 0.75 kg / cm ² , the thickness of the pellet is 7.3 mm, it is easy to break but the dissolution time is still too long.

Under a pressure of 0.6 kg / cm ^, a pellet of good consistency and easily dissolving is presented. The thickness of the tablet is 7.6 mm, which therefore represents a reduction of more than half of the initial filling volume of the powder in the tablet press.

If a pressure less than 0.5 kg / cm ² is applied, a pellet of the order of 8 mm thick is obtained, which however crumbles easily and is therefore not suitable.

It should be noted that, for most of the pellets which do not have good dissolution characteristics, the appearance on the external surface of the tablet or of the tablet is observed of a film which is probably at the origin of the poor properties of dissolution.

The tablets of the above-mentioned composition are not toxic. Their disgusting taste is a barrier, however, to accidental ingestion of these tablets, among others by children. However, in the case of such ingestion, it would only result in a temporary intestinal disturbance without causing serious disturbances.

The tablets are characterized by the ease of their industrial preparation, the rigor of the dosage they allow and the convenience of their use.

It should be noted that, with a view to accelerating the disintegration of the tablets in contact with water, the use of effervescent materials consisting inter alia of a mixture of an organic acid in soluble form such as citric acid and sodium carbonate and bicarbonate is possible but is generally superfluous.

As previously indicated, other usual additives and adjuvants well known to those skilled in the art can be used.

The tablets are produced so as to preferably obtain unit dosage forms of 2.4 to 2.5 g

Two of these tablets are recommended for pre-washing and three tablets for washing, for a total weight of approximately 12.5 g per 5 kg of laundry to be machine washed with the amount of water prescribed by the manufacturer of the machine.

Generally, the pH of the preparation is of the order of 8 and 10 if the dissolved _'oomprimés according to the above recommendations.

In this way a detergent without mordants and largely biodegradable is obtained. In addition, the product is presented in a unit dosage form which is easy to use, compact and exerts a good washing effect despite the low concentration of the constituents in the detergent.

Although particular preferred embodiments of the invention have been described, it should be understood that many variations are possible while remaining within the scope of the invention. The technician in the branch will be able in particular to adapt the detergent compositions according to the desired uses and in particular by laboratory tests and washing tests, to adapt the different constituents of the mixture to the different desired results among which the following properties must be particularly taken into account. consideration for the new tablets obtained according to the invention, namely: solubility and speed of disintegration and dissolution of the tablets in water, consistency of the tablets, satisfactory turbidity of the bath, pH stability and finally cost price which constitute the advantages principal of the invention.

Unless otherwise indicated, all the proportions indicated in the present specification and the claims relate to proportions or percentages expressed by weight.

Claims (8)

1. Detergent preparation characterized in that it contains sodium carboxymethylcellulose (CMC) having a viscosity of the order of 15,000 to 25,000 m Pas, measured at 20 ° C and in the form of a 2% solution , at a rate of 5 to 25%, the balance consisting of the usual ingredients of a detergent composition, namely surfactants and washing aids. 2. Preparation according to claim 1 characterized in that the sodium carboxymethylcellulose used has a viscosity of 20,000 m Pas measured at 20 ° C and in the form of a 2% solution. 3. Preparation according to claims 1 or 2 characterized in that it contains 15% by weight of said sodium carboxymethylcellulose. 4. Preparation according to any one of claims 1 to 3 characterized in that it contains as surfactant at least 35% and preferably at least 45% by weight of double lauryl sulfate and sodium. 5. Preparation according to any one of claims 1 to 4 characterized in that it is in the form of unitary tablet preferably weighing about 2.4 to 2.5 g. 6. Detergent preparation according to any one of claims 1 to 5 characterized in that it is obtained from a conventional composition of detergents in compressed powder in the presence of sodium carboxymethylcellulose by carrying out a compression such as at the start of conventional powders, tablets are produced whose volume, compared to the starting powders, is reduced by at least half. 7. Detergent composition according to any one of claims 1 characterized in that it is free of sodium polyphosphates and that it is largely biodegradable. 8. Detergent composition according to any one of claims 1 to 7 characterized in that it is compressed to a pressure of less than 1 kg / cm ² , preferably a pressure of the order of _0.6 kg / cm ² .