FR2781810A1 - MULTI-LAYER DETERGENT TABLET FOR WASHING LAUNDRY AND METHOD OF MANUFACTURE - Google Patents

Abstract

Tablet of the multilayer type for washing laundry, characterized in that it consists of a sandwich structure comprising at least three layers, respectively: - two outer layers comprising an enzymatic system; - a central layer comprising a peroxidizing system; the central layer being capable of being dissolved in a period of less than or equal to 80 seconds after complete dissolution of the two outer layers.

Description

I

  MULTI-LAYER DETERGENT TABLET FOR WASHING LAUNDRY

AND MANUFACTURING METHOD

  The invention relates to a new detergent tablet for washing clothes. It also relates to the method of manufacturing said tablet. Products for washing clothes can be in various forms, solid or liquid. Liquid forms are less and less

  less used, solid forms being preferred for their minimum bulk and their maximum efficiency.

  Thus, in document EP-A-0 846 756, tablets have been described which are in the form of a central core coated with a mixture based on effervescent and disintegrating agents. A drawback of this type of tablet lies in the fact that the core being very little compacted (the tableting pressure is between 0.5 kN and 1.5 kN), it easily disintegrates during storage or during its handling. We have also proposed a monolayer tablet manufactured from an atomized base which can be densified and granulated, to which the various constituents necessary for washing are then added, such as an enzymatic system,

  whitening system. The powder thus obtained is then pelletized on tablet presses of the rotary type.

  Even if the problem of the disintegration of the pellet is solved, this type of product nevertheless has the drawback of intimately mixing all of the constituents and in particular the peroxidizing system and the enzymatic system, which jeopardizes the stability of the product and inevitably leads to loss of activity. Furthermore, these monolayer tablets contain an anionic surfactant30 of the sodium alkylbenzene sulfonate type, which can cause, during the manufacture of the pastille, phenomena of sticking of the powder on the punches.

of the machine.

  In other words, the problem which the invention proposes to solve is

  provide a shelf for washing clothes that is stable over time.

  Another object of the invention is to provide a tablet whose manufacture is simple to implement.

  To do this, the invention proposes a tablet of the multilayer type for washing clothes, characterized in that it consists of a sandwich structure comprising at least three layers, respectively: - two external layers comprising an enzymatic system; - a central layer comprising a peroxidizing system; the central layer being able to dissolve in a time less than or equal to 80

  seconds after complete dissolution of the two outer layers.

  This sandwich structure therefore makes it possible to solve the problem of the stability of the product during storage by separating the peroxidizing activity from the layer.

  central, i.e. the bleaching activity, of the enzymatic activity of the outer layers.

  In addition, the tablet is in the form of at least three flat layers superimposed on each other by compacting their widest surface. In this way, the

  dissolution of the apparent periphery of the intermediate layer during the dissolution of the outer layers is very limited.

  Furthermore and above all, the dissolution in a very short time of the central layer makes it possible to prevent the tablet from becoming fixed on the laundry thus leading to the formation of indelible stains due to the presence of the peroxidizing system.25 In practice, for obtain a tablet having a uniform structure and simplify the manufacturing process, the two outer layers have a composition

identical chemical.

  To make it possible to obtain a very short dissolution time of the central layer, said central layer undergoes during manufacturing, a weak precompression force. In practice, the dissolution time of the central layer as such is between 20 seconds and 75 seconds, while the dissolution time

  outer layers is between 30 seconds and 90 seconds.

  According to a preferred embodiment of the invention, the dissolution time of the outer layers is one minute, while that of the central layer is 30 seconds after complete dissolution of the outer layers. 5

  In the following description and in the claims, "enzymatic system"> denotes a set of enzymes of the protease, amylase,

lipase and cellulase.

  Furthermore, to obtain an immediate action of the detergent on the laundry, the outer layers comprise an anionic and / or nonionic surfactant

  first of all allowing the fiber to be wetted and then removing the dirt by reducing the surface tension.

  However, according to another characteristic of the invention, in order to eliminate the phenomena of sticking of the powder on the machine during the manufacture of the

  tablets, the nonionic surfactant is distributed between the outer layers and the central layer.

  Advantageously, the anionic surfactant is chosen from the group comprising sodium alkylbenzene sulphonate, alkyl sulphate and alkyl ether sulphate. Likewise, the nonionic surfactant is chosen from the group

  including ethoxylated fatty alcohols, ethoxylated alkylphenols.

  In addition, to improve washing efficiency and soften the water, the outer layers include an anti-scale agent.

  In practice, the anti-scale agent is chosen from the group comprising phosphonate, silicoaluminate, tripolyphosphate (TPP), homo or

  copolymers of acrylic acid and citrates.

  Finally, so as to activate the peroxidizing system of the central layer, and

  thus implementing the bleaching activity, the outer layers comprise a bleach activator.

  However, the bleach activator can be incorporated into the core layer.

  In practice, the bleach activator is chosen from the group comprising tetraacetylene diamine (TAED), pentaacetyl glucose (PAG), and

tetraacetyl glycoluryl (TAGU).

  Said bleach activator thus makes it possible to activate the peroxidizing system contained in the central layer, in practice, perborate or percarbonate, the reaction leading to the formation of hydrogen peroxide and acid

  peracetic. Of course and as already said, the peroxidizing system exerts its whitening action only after dissolution of the two outer layers.

  To give the laundry a pleasant smell, the central layer contains

also a perfume.

  Advantageously, in order to impart antiseptic and sanitizing properties to the washing tablet, the central layer comprises a disinfecting agent

  in the form of coated granules capable of being released as a function of the temperature of the washing water.

  The disinfecting agent is coated in a manner known to a person skilled in the art, in particular by spraying fat onto the

  disinfectant particles, such as triglycerides or waxes.

  Thus, for certain types of washing, the washing tablet may diffuse the disinfecting agent at a given temperature of the washing water, depending on the coating chosen. The invention also relates to the process for manufacturing said washing.

multilayer tablet.

  According to this process: - first of all the various constituents forming the external layers are mixed; - in parallel, the various constituents forming the central layer are mixed; - Is deposited on a support and then cup part of the mixture intended to form the first outer layer, then deposited on said first outer layer the mixture forming the central layer and then the complex obtained; - then the remaining part of the mixture forming the second outer layer is deposited on the central layer,

  - Finally, the tablet obtained is pressed.

  In practice, the weight of the outer layers is between 10 and 20 grams, advantageously between 12 and 17 grams. Likewise, the weight of the central layer is between 10 and 20 grams, advantageously between 10 and

grams.

  In addition, according to an essential characteristic of the process, the first outer layer and the central layer are packed to a precompression value of between 10 kg / cm2 and 100 kg / cm2, while the tablet obtained is pressed to a

  value between 20 kg / cm2 and 400 kg / cm2.

  In practice, tablets of 40 g, diameter 45 are manufactured, the

  hardness is between 4 and 15 kP, advantageously 5 to 7 kP.

  The invention and the advantages which result therefrom will emerge more clearly from the following examples.

  Example 1 - Preparation of a multi-layer tablet with phosphate

  The following tests were carried out on a laboratory scale.

  To manufacture the detergent tablet for washing the laundry of the invention,

we proceed as follows.

  First of all, an atomized base is prepared, each of the constituents of which is used in the composition of the outer layers. This atomized base comprises: - sodium alkylbenzenesulfonate 3.6 g - soap 0.225 g - optical brighteners 0.09 g - phosphonate 0.27 g - maleic acrylic copolymer 0.45 g - sodium disilicate 0.90 g - carbonate 3.375 g - sulfate 2.34 g

  A mixture 1 is then prepared intended to be mixed with the atomized base to form the outer layers.

  It is indeed necessary to provide a separate mixture 1 insofar as some of the constituents likely to enter into the composition of the

  outer layer cannot be atomized because they are destroyed by heat. This is particularly the case for enzymes and anti-foam.

  The composition of mixture 1 is as follows: - hydrated sodium tripolyphosphate 18 g - ethoxylated fatty alcohols 0.9 g - enzymes 0.9 g - antifoam 0.9 g According to the process of the invention, the base is mixed atomized with mixture 1. The mixture obtained is separated into two equal parts intended to form

the outer layers.

  The first half is placed on a support and then it is packed by subjecting it to a precompression force of 15 kg / cm2.

  A mixture 2 is then prepared intended to form the central layer comprising: - sodium perborate 6.75 g - TAED 1.8 g - ethoxylated fatty alcohols 1.8 g - perfume 0.225 g - silicoaluminate 2.475 g

  This mixture 2 is deposited on the first outer layer and then packed by subjecting it to a precompression force of 15 kg / m2.

  Finally, the mixture intended to form the second outer layer is deposited on the central layer and then the tablet obtained is subjected to a pressure of 60 kg / m2. Example 2 - phosphate-free tablet

  In example 2, the procedure is similar to example 1.

  First of all, an atomized base is prepared comprising: - sodium alkylbenzenesulfonate 5.85 g - soap 0.36 g - optical brighteners 0.2 g - soda ash 8.5 g - bicarbonate 8 g - phosphonate 1 g acrylic copolymer maleic 1.6 g - sodium disilicate 0.3465 g A mixture 1 is then prepared which is intended to form the external layers with the atomized base, this mixture comprising: - sodium carbonate 2.025 g sodium silicoaluminate 9 g - ethoxylated fatty alcohols 2.115 g - enzymes 0.9 g - anti-foam 0.675 g Finally, mixture 2 is prepared to form the middle layer comprising: - sodium percarbonate 6 g - sodium disilicate 2.025 g - TAED 0.81 g - perfume 0.125 g

  The tablets are produced according to the same process as in Example 1.

  The advantages of the invention appear clearly from the description.

  Note in particular the ability of the tablet to dissolve quickly thus preventing the peroxidant system from attaching to the laundry.

  In addition, by virtue of its multilayer structure, the tablet of the invention has high stability by separating the peroxidizing system and the enzymatic system.

Claims (7)

  1 / Multilayer type shelf for washing clothes, characterized in that it consists of a sandwich structure comprising at least three layers, respectively: - two external layers comprising an enzymatic system; - a central layer comprising a peroxidizing system; the central layer being able to be dissolved in a period less than or equal to 80   seconds after complete dissolution of the two outer layers.   2 / Tablet according to claim 1, characterized in that the outer layers have an identical chemical composition.   3 / tablet according to one of claims 1 to 2 characterized in that the outer layers and the central layer further comprise a surfactant non-ionic.   4 / Tablet according to one of claims 1 to 3, characterized in that the   central layer comprises a disinfecting agent in the form of coated granules capable of being released as a function of the temperature of the washing water.   / Tablet according to one of claims 1 to 4, characterized in that the   outer layers dissolve in a time between thirty and ninety seconds, preferably one minute.   6 / tablet according to one of claims 1 to 5, characterized in that the central layer dissolves in a period between twenty and seventy five   seconds, preferably thirty seconds.   7 / A method for manufacturing a multilayer tablet according to one of claims 1 to 6, according to which:   - firstly mixing the different constituents forming the outer layers; - in parallel, the various constituents forming the central layer are mixed; - a portion of the mixture intended to form the first external layer is deposited on a support and then it is packed, - the mixture forming the central layer is then deposited on said first external layer and then the complex obtained is packed, - then, it is deposited on the central layer the remaining part of the mixture forming the second outer layer;   - Finally, the tablet obtained is pressed.   8 / A method according to claim 7 characterized in that the first outer layer and the central layer are packed to a precompression value included   between 10 kg / cm2 and 100 kg / cm2, while pressing the tablet obtained at a value between 20 kg / cm2 and 400 kg / cm2.