EP0063512B2 - Bleach activator granules, their preparation and their use in detergent and bleaching compositions - Google Patents

Abstract

1. Claims for the Contracting states : BE, CH, DE, FR, GB, IT, LI, LU, NL, SE Bleaching activator in granular form comprising tetraacetylethylenediamine and a coating agent comprising at least one alkali metal polyphosphate and an alkali metal derivative of cellulose, characterised in that it is composed of : - 55 to 90% by weight of tetraacetylethylenediamine and - 10 to 45% by weight of coating agent. 1. Claims for the Contracting State : AT Process for washing articles based on natural, synthetic or artificial fibres, characterised in that there is used a bleaching activator in granular form, comprising tetraacetylethylenediamine and a coating agent comprising at least one alkali metal polyphosphate and an alkali metal derivative of cellulose, and composed of : - 55 to 90% by weight of tetraacetylethylenediamine and - 10 to 45% by weight of coating agent.

Description

The present invention relates to granules of coated bleaching activator, to the process for coating and granulating said activator and to the use of the granules obtained in or with detergent and bleaching compositions.

More specifically, the subject of the invention is N, N, N ', N'-tetraacetylethylenediamine granules coated, their preparation and their use in detergency.

• - par tétraacétyléthylènediamine: la N,N,N',N'-tétraacétyléthylènediamine,
• - par "percomposé", un sel qui libère un peroxyde d'hydrogène en solution aqueuse, comme il en est par exemple des perborates, percarbonates, persilicates et perphosphates de métaux alcalins;
• - par "composition détergente", dénommée aussi "lessive" un produit solide contenant au moins un tensio-actif organique, au moins un percomposé et au moins un builder qui est un adjuvant de détergence dont l'une des fonctions est de séquestrer les ions responsables de la dureté de l'eau;
• - par "matières textiles": aussi bien les fibres naturelles, artificielles et/ou synthétiques que les produits manufacturés à partir de celles-ci.
• - par "granulométrie": l'expression de tailles des particules par leur diamètre moyen. On définit le diamètre moyen comme étant un diamètre tel que 50 % en poids des particules ont un diamètre supérieur ou inférieur au diamètre moyen.

In the following description of the present invention, it should be understood:

• - by tetraacetylethylenediamine: N, N, N ', N'-tetraacetylethylenediamine,
• - By "percomposite", a salt which releases a hydrogen peroxide in aqueous solution, as it is for example perborates, percarbonates, persilicates and perphosphates of alkali metals;
• - by "detergent composition", also known as "detergent", a solid product containing at least one organic surfactant, at least one percomposite and at least one builder which is a detergency builder, one of whose functions is to sequester ions responsible for the hardness of the water;
• - by "textile materials": both natural, artificial and / or synthetic fibers as well as products manufactured from them.
• - By "particle size": the expression of particle sizes by their average diameter. The mean diameter is defined as being a diameter such that 50% by weight of the particles have a diameter greater or less than the mean diameter.

The conventional detergent compositions used for washing textile materials include a surfactant (anionic, non-ionic, cationic or amphoteric), a builder and a bleaching compound.

It is well known that percomposites and in particular perhydrates release, in aqueous media and under certain conditions, an amount of oxygenated water which, thanks to its oxidizing power, allows the elimination of certain colored spots.

The per-compounds used in detergent compositions exhibit sufficient oxidizing activity only at temperatures generally above 60 ° C.

To increase the bleaching effect at low temperature of the detergent or bleaching composition, it has been recommended to add thereto, an organic activator of the compound. The activator reacts with the hydrogen peroxide released by the compound, to form in the detergent medium, an active bleaching agent at lower temperatures, for example between 20 and 50 ° C.

Among the known organic activators, tetraacetylethylenediamine has been found to be particularly effective. Unfortunately, this activator has storage stability problems when incorporated into detergent compositions. On contact with the other constituents of the detergent composition, alkaline substances, percomposite, and hydrated compounds, the activator tends to hydrolyze and perhydrolysate. This partial decomposition leads to the appearance of pungent odors and coloring as well as a reduction in its whitening power.

To overcome these drawbacks, attempts have been made to protect tetraacetylethylenediamine by means of a coating which would isolate it from the other constituents liable to cause its degradation.

• - il doit être solide à la température ambiante et doit donc avoir un point de fusion supérieur à 40°C;
• - il doit être inerte vis-à-vis de l'activateur et des composants habituels des compositions détergentes;
• - il doit être soluble ou dispersable dans le bain de lavage;
• - il doit faciliter le passage en solution de la tétraacétyléthylènediamine et n'apporter aucun retard à sa dissolution;
• - il ne doit pas diminuer les pouvoirs détergents et de blanchiment des bains de lavage;
• - il est préférable qu'il ait une activité particulière en détergence et par conséquent, préexiste dans les compositions détergentes;
• - il est préférable qu'il soit bon marché.

Many imperatives preside over the choice of the coating agent, namely:

• - it must be solid at room temperature and must therefore have a melting point above 40 ° C;
• - It must be inert vis-à-vis the activator and the usual components of detergent compositions;
• - it must be soluble or dispersible in the washing bath;
• - It must facilitate the passage into solution of tetraacetylethylenediamine and bring no delay in its dissolution;
• - it must not diminish the detergent and bleaching powers of the washing baths;
• - It is preferable that it has a particular activity in detergency and therefore preexists in detergent compositions;
• - it is better that it is cheap.

• - les granulés obtenus doivent libérer les cristaux de la tétraacétyléthylènediamine dès le début du cycle de lavage pour former les ions de l'acide peracétique, le plus rapidement dans le bain lessiviel;
• - les granulés doivent être bien liés et avoir des propriétés mécaniques suffisantes pour ne pas être désintégrés prématurément au cours de la fabrication de la composition détergente et de sa manipulation, en particulier, conditionnement et transport;
• - enfin les granulés doivent avoir une composition telle que la quantite d'agent d'enrobage introduit dans la composition détergente ne provoque pas un déséquilibre de sa formulation conduisant alors a des effets secondaires non recherchés tels que, par exemple; la redéposition ou un mauvais contrôle des mousses.

In addition to these different conditions which the coating agent must satisfy, it should be noted that the nature of the coating agent affects the characteristics of the granules to be obtained. Consequently, the choice of coating agent must also take into account the qualities required of the granules, which are as follows:

• - The granules obtained must release the crystals from tetraacetylethylenediamine from the start of the washing cycle to form the ions of peracetic acid, as quickly as possible in the washing bath;
• - The granules must be well bonded and have sufficient mechanical properties not to be prematurely disintegrated during the manufacture of the detergent composition and its handling, in particular, packaging and transport;
• - Finally, the granules must have a composition such that the amount of coating agent introduced into the detergent composition does not cause an imbalance in its formulation then leading to unintended side effects such as, for example; redeposition or poor control of mosses.

There is therefore, also, a difficulty in solving at the level of the composition of the granules to be obtained which, on the one hand involves a minimum quantity of coating agent so as not to unbalance the detergent composition and on the other hand, a maximum amount of coating agent to increase the binding effect and the mechanical properties and obtain effective protection of tetraacetylethylenediamine.

There is also a difficulty to be overcome in the manufacture of granules with a high content of tetraacetylethylenediamine. Indeed, the latter has no "self-agglomeration" property, and it it is necessary to use a coating agent having binding properties and the problem of the granulation of tetraacetylethylenediamine will be all the more difficult to solve the lower the amount of coating agent.

It emerges from all of the above that the choice of coating agent is difficult in order to obtain good protection of the tetraacetylethylenediamine, during storage, in order to preserve its bleaching activity as much as possible.

It has long been proposed to use different types of coating of tetraacetylethylenediamine. Thus, French Patent 2,281,160 describes, as coating substances, long chain fatty acids such as myristic, stearic acids, hydrogenated tallow fatty acids, acid waxes or oxidized paraffin waxes. The disadvantage of using these organic substances is obtaining granules which are often difficult to handle due to the physical nature of the binder material. In addition, there is a delay in the formation of peracetic acid ions.

Furthermore, French patent 2 109 941 describes granular compositions containing from 5 to 50% by weight of the bleaching activator which is tetraacetyl glycolurile and from 95 to 50% by weight of a coating material comprising sodium triphosphate. Since the amount of binding agent used is large, it is not possible to obtain granules with a high concentration of activator.

It is also described in French Patent No. 2,460,997 "particulate compounds" containing 10 to 90% by weight of tetraacetylethylene diamine associated with a granulating agent which is, preferably, a mixture of sodium triphosphate and sodium triphosphate potassium. It is indicated in the description that carboxymethylcellulose can also be used as a coating agent.

The present invention proposes to provide coated tetraacetylethylenediamine granules satisfying all the conditions listed above and avoiding the aforementioned drawbacks.

• - de 55 à 90 % en poids de tétraacétyléthylènediamine;
• - de 10 à 45 % en poids du mélange triphosphate de métal alcalin et dérivé de cellulose d'un metal alcalin.

It has now been found, and this is what constitutes one of the objects of the present invention, a bleach activator in granulated form composed of a mixture of tetraacetylethylenediamine and of alkali metal triphosphate coated with a cellulose derivative of alkali metal and which contains:

• - from 55 to 90% by weight of tetraacetylethylenediamine;
• - from 10 to 45% by weight of the triphosphate mixture of alkali metal and cellulose derivative of an alkali metal.

The protection of tetraacetylethylenediamine in the form of the granules of the invention makes it possible to suppress the degradation of the latter during storage and does not in any way alter the activating qualities of tetraacetylethylenediamine on the percomposites.

In addition, it was unexpectedly found that the rate of dissolution of the granulated and coated tetraacetylethylenediamine according to the invention is greater than the rate of dissolution of tetraacetylethylenediamine alone. The practical interest of the invention is therefore to obtain very quickly the formation of ions of peracetic acid, in the washing medium.

Finally, it should be noted that the incorporation of tetraacetylethylenediamine in the detergent compositions is facilitated because of the possibility of carrying out the dry mixing of the granules of the invention with the other constituents of the detergent composition.

Another object of the present invention is the process for preparing the said bleach activator in granulated form, characterized in that a pulverulent mixture of the tetraacetylethylenediamine and the alkali metal triphosphate is carried out and which is sprayed on the bed mobile thus formed a solution of an alkali metal cellulose derivative.

It will be mentioned, as of now, that by "solution" is meant both a solution and a dispersion of the cellulose derivative.

The nature and characteristics of the components involved in the granules of the invention will be specified below.

The tetraacetylethylenediamine to be treated is suitably in the form of particles having a particle size between 0.02 and 0.25 mm and preferably between 0.05 and 0.15 mm. It is preferable that the tetraacetylethylenediamine used has the aforementioned particle size distribution because if the particles are too small, there is formation of undesirable dust and if the particles are too large, there may be problems with agglomeration and during the use in detergency, the dissolution of tetraacetylethylenediamine will be slowed down. The particle size of tetraacetylethylenediamine is commonly determined, for example, by dry sieving, by sedimentation or by direct particle counting using a COULTER ^O counter based on the recording of conductometric disturbances which accompany the passage of the particles through a diaphragm of given size.

The alkali metal triphosphates according to the invention are preferably used in anhydrous form.

Among the aforementioned alkali metal triphosphates, sodium triphosphate is preferably chosen. It is used in its commercial form which contains impurities of metals such as iron, copper, nickel. Generally, the quantity of metal ions does not exceed 200 p. p. m. It is preferred to use a sodium triphosphate having a reduced content of metallic impurities, for example, between 20 and 100%. p. m.

As for the particle size of sodium triphosphate, determined in an identical manner to that of tetraacetylethylenediamine, it is between 0.02 and 0.08 mm, which corresponds to sodium triphosphate in common use in detergency.

The component involved in the coating agent is organic in nature since it is a derivative of

cellulose. As such, mention may be made of carboxymethylcellulose, methylcellulose or hydroxyethylcellulose.

These cellulose derivatives are preferably used in the form of their sodium salt.

Sodium carboxymethylcellulose is a raw material of choice. No specific characteristic of particle size is required since it is used in the form of an aqueous solution. The sodium carboxymethylcellulose commonly used in detergents is used according to the invention. It has a degree of substitution varying from 0.5 to 0.7: the degree of substitution expressing the average number of carboxyl radicals attached to each link in the cellulosic chain. With regard to its degree of polymerization and which translates the length of the cellulosic chain and determines the viscosity, it will be determined so that a solution having the desired viscosity is obtained which will be specified later.

• - de 55 à 90 % en poids de tétraacétyléthylènediamine;
• - de 10 à 45 % en poids du mélange triphosphate de métal alcalin et dérivé de cellulose d'un métal alcalin.

The various components defined above are used in quantities such that granules of bleach activator are obtained having the following composition:

• - from 55 to 90% by weight of tetraacetylethylenediamine;
• - from 10 to 45% by weight of the triphosphate mixture of alkali metal and cellulose derivative of an alkali metal.

Sodium triphosphate and sodium carboxymethylcellulose being preferably chosen, we will define their proportions used, but it goes without saying that the values given below are also suitable when using another triphosphate or another cellulose derivative.

The quantity of sodium carboxymethylcellulose used in the coating agent, expressed by the weight ratio (sodium carboxymethylcellulose / tetraacetylethylenediamine) can vary within an interval the limits of which are fixed as follows: the lower limit is determined so that the granules obtained have the required mechanical resistance properties and the upper limit is defined as a function of at least two parameters to be observed: namely, on the one hand, a physico-chemical parameter which requires that discard an excess of sodium carboxymethylcellulose which would risk delaying the release of tetraacetylethylenediamine and the formation of peracetic acid ions and on the other hand, a process constraint in the production of granules which would then require the setting work with a larger amount of water which should be removed by drying and which would interfere, or even, make granulation impossible. The amount of sodium carboxymethylcellulose is chosen such that the said ratio varies from 1/100 to 1/10, preferably from 1/30 to 1/15.

The amount of sodium triphosphate involved, expressed by the weight ratio (sodium triphosphate / tetraacetylethylenediamine) is not critical and can vary within wide limits. However, it is a function of the amounts of tetraacetylethylenediamine and of sodium carboxymethylcellulose and will therefore be fixed so that its weight ratio with tetraacetylethylenediamine varies from 1/10 to 1/1, preferably between 1/4 to 2/3.

• - de 60 à 75 % en poids de tétraacétyléthylènediamine;
• - au moins 20 % en poids de triphosphate de sodium;
• - de 2 à 4 % en poids de carboxyméthylcellulose de sodium.

The preferred compositions of the granules of the invention are given below, by way of examples: (the percentages are expressed by weight of dry matter):

• - from 60 to 75% by weight of tetraacetylethylenediamine;
• - at least 20% by weight of sodium triphosphate;
• - from 2 to 4% by weight of sodium carboxymethylcellulose.

As regards the method for preparing the granules of the invention, it has been found that it is advantageous to carry out the coating at the same time as an agglomeration leading directly to granules suitable for addition to the detergent compositions.

The method of the invention consists in first making the pulverulent mixture of tetraacetylethylenediamine and of the alkali metal triphosphate, preferably sodium brought to the desired particle size and in the suitable ratio, to pour the mixture obtained above all device for constituting a mobile bed, on which is sprayed a solution of the cellulose derivative of alkali metal, preferably in sodium form.

The process for preparing the granules of the invention is described below by choosing sodium triphosphate as the alkali metal triphosphate and sodium carboxymethylcellulose as the alkali metal cellulose derivative, but this process can be easily adapted by '' skilled in the art when using another triphosphate or another cellulose derivative.

According to a preferred embodiment of the invention, enabling continuous bleaching granules to be obtained industrially, the procedure is as follows:

We start by preparing a homogeneous powder mixture of tetraacetylethylenediamine and sodium triphosphate. To do this, the two aforementioned components having the desired particle size, are first weighed and introduced into a mixer. A mixer is used which can be any device which makes it possible to obtain a dry mixture, without destroying the particle size. Suitable for this operation, rotary drum mixers or rotary Y-mixers, or mixers of the semi-mixer type.

The mixture obtained is then poured into a granulator which can be a rotary drum granulator having a large moving charge.

An illustration of this type of device used in a preferential manner is a bezel with a cylindrical bowl equipped with devices for introducing and discharging the powder and also provided with a device for spraying liquid under pressure. The bezel has a bowl, the inclination of the axis of rotation of which is preferably 43 to 45 ° relative to the horizontal.

A filler consisting of tetraacetylethylenediamine and sodium triphosphate is introduced into the bezel, from 30 to 100 kg per m ³ of bezel, preferably. from 40 to 80 kg per m ³ of bezel.

The pulverulent mixture is kept in motion thanks to the rotation of the bezel: the speed of rotation of the bezel is such that the tangential speed of the bezel is 0.5 to 3 m / s, preferably 1 to 2 m / s.

Furthermore, the preparation of the sodium carboxymethylcellulose solution which will be sprayed is carried out. To prepare said solution, it is sought to use the minimum quantity of water in order to avoid or minimize the drying operation. The amount of water to be used is a function of the concentration of sodium carboxymethylcellulose to be obtained, which should not be too high because there would be too high a viscosity preventing any spraying. This concentration will be defined so that a spray solution with a final viscosity of less than 0.2 Pa is obtained. s: the viscosity of 0.2 Pa - s corresponds to a measurement carried out at 50 ° C with a shear viscometer on a 5% solution: the speed gradient chosen for the measurement is between 25 s ^-1 and 200 s- ^1.

Preferably, a solution of sodium carboxymethylcellulose having a viscosity of between 0.10 and 0.15 Pa - s is used.

Generally, using a sodium carboxymethylcellulose of "detergency" quality, solutions containing from 2 to 10%, preferably from 3 to 8% by weight of sodium carboxymethylcellulose, are prepared.

The sodium carboxymethylcellulose solution to be sprayed is prepared and maintained at a temperature preferably between 30 and 80 ° C using an appropriate heating device.

The sodium carboxymethylcellulose solution is sprayed onto the pulverulent mixture by means of a spray nozzle under pressure of 2 to 10 bars, preferably from 4 to 5 bars.

The duration of the spraying depends on the quantity of sodium carboxymethylcellulose which it is desired to introduce into the granules.

The finished granules are removed from the bowl of the bezel using a discharge device such as a scraper or other type. A wet powder is obtained having a water content of 20 to 40%, preferably 25 to 35%.

We work advantageously continuously. To do this, the bezel is continuously fed so as to obtain an average residence time of the granules in the bezel of 10 to 60 minutes and the granules obtained are evacuated as and when obtained by means of an appropriate evacuation device. .

The granules obtained then undergo a simple screening and by this single operation, they acquire the particle size desired for their use.

Generally, so that there is no segregation of the granules during the storage of the detergents, a particle size distribution such that the diameter of the granules ranges from 0.4 to 2.0 mm and, preferably, from 0.6 to 1.2 mm.

According to the process of the invention, the fine particles remain in the bezel. On the other hand, the large granules which constitute the rejection of screening are crushed by any suitable device and recycled in the dredger.

By way of illustration, it may be mentioned that the screening can be carried out by a simple passage over a rotating or oblique grid having an adequate mesh opening.

The coating and granulation process according to the invention makes it possible, by the choice of particle sizes of the pulverulent materials and by the screening operation succeeding the granulation, to obtain any particle size distribution defined above.

After this particle size selection operation, the granules are dried in a current of hot air generally from 30 to 60 ° C.

Drying can be done in any way. One can, for example, carry out a tunnel drying by moving the granules deposited on a conveyor belt against the flow of hot air. The granules can also be dried in an oven, for example, with a rotary hearth.

The drying device will be chosen so that the granules are not broken up during drying.

The granules which are the subject of the invention have a regular particle size, good mechanical properties, and can be easily incorporated into detergent and bleaching compositions.

The introduction of the granules according to the invention into the detergent and bleaching compositions is generally carried out by post-addition to the detergent composition dried after atomization, by simple dry mixing.

In addition to their use in detergent and bleaching compositions, the granules of the invention can be added directly to the washing bath comprising a detergent and bleaching composition containing a compound in the case of industrial use.

The detergent compositions in which the bleaching granules can be incorporated, comprise, in addition to the per-compound used for bleaching, at least one anionic, nonionic, cationic, amphoteric surfactant and at least one builder.

As examples of bleaching compounds which can be used, mention should be made in particular of sodium perborate tetrahydrate which is the most commonly used compound, as well as various other conventional perco-compounds, such as sodium perborate monohydrate, sodium percarbonate sodium, sodium persilicate and sodium perphosphates.

For the choice of surfactant, one can refer, among others, to the encyclopedia "Encyclopedia Chemical Technology - Kirk OTHMER - volume 19" or to the various works of the Surfactant Sciences Series, Marcel DEKKER Inc - Vol . 1: Nonionic Surfactants by Martin J. SCHICK; Flight. 4: Cationic Surfactants by Eric JUNGERMANN; Flight. 7: Anionic Surfactants by Warner M. LINFIELD.

• - les savons de métaux alcalins tels que les sels sodiques ou potassiques d'acides gras saturés ou insaturés ayant de 8 à 24 atomes de carbone et de préférence de 14 à 20 ou des dérivés d'acides aminocarboxyliques comme le N-lauryl sarconisate de sodium, le N-acylsarconisate de sodium.
• - les sulfonates alcalins tels que les alcoylsulfonates, les arylsulfonates ou les alcoylarylsulfonates; en particulier les alcoylbenzènesulfonates de formule R₁-C₆H₄-SO₃M₁ dans laquelle le radical R, est un radical alcoyle linéaire ou ramifié contenant de 8 à 13 atomes de carbone tel que par exemple un radical nonyle, dodécyle, tridécyle et M₁ représente un atome de sodium, de potassium, un radical ammonium, de la diéthanolamine ou de la triéthanolamine; les alcoylnaphthalènesulfonates tels que le nonylnaphthalènesulfonate de sodium. D'autres sulfonates peuvent être employés tels que les N-acyl, N-alcoyltaurates de formule R₂-CO-N(R2')-CH₂-CH₂-SO₃Na où R₂ est un radical alcoyle ayant de 11 à 18 atomes de carbone et R₂' est un radical méthyle, éthyle: comme par exemple le N-oléoyl, N-méthyltaurate ou le N-palmitoyl, N-méthyltaurate de sodium.
• - les esters β-sulfoéthyliques des acides gras par exemple des acides laurique, myristique, stéarique: les oléfino-sulfonates contenant de 12 à 24 atomes de carbone, obtenus par sulfonation à l'aide d'anhydride sulfurique d'a-oléfine comme le dodécène-1, le tétradécène-1, l'hexadécène-1, l'octadécène-1, l'eicosène-1, le tétracosène-1.
• - les sulfates et les produits sulfatés; parmi les sulfates d'alcoyle répondant à la formule R₃OSO₃M₁, on peut citer ceux où le radical R₃ est un radical lauryle, cétyle, myristyle et M₁ ayant la signification donnée précédemment; les huiles et graisses naturelles sulfatées; le sel disodique de l'acide oléique sulfaté; les alcools gras polyoxyéthylénés et sulfatés de formule:
  
  dans laquelle le radical R₄ est un radical alcoyle contenant de 6 à 16 atomes de carbone tel que par exemple un radical myristyle ou un radical alcoyle linéaire ou ramifié comme par exemple un radical hexyle, octyle, décyle, dodécyle, n, est le nombre de moles d'oxyde d'éthylène pouvant varier de 1 à 4 et M_t ayant la signification donnée précédemment; les alcoylphénols polyoxyéthylénés et sulfatés de formule:
  
  dans laquelle le radical R₅ est un radical alcoyle linéaire ou ramifié contenant de 8 à 13 atomes de carbone tel que par exemple un radical octyle, nonyle, dodécyle, n₂ est le nombre de moles d'oxyde d'éthylène pouvant varier de 1 à 6 et M₁ ayant la signification donnée précédemment.
• - les esters primaires et secondaires de l'acide orthophosphorique ou l'un de ses sels qui peuvent être représentés pour les phosphates d'alcoyle par la formule (R₆0) PO (OM₂)₂ et pour les phosphates de dialcoyle par la formule (R₆0)₂ PO (OM₂) dans lesquelles le radical R₆ est un radical alcoyle linéaire ou ramifié contenant de 6 à 12 atomes de carbone et M₂ représente un atome d'hydrogène, de sodium ou de potassium. A titre d'exemples de radical R₆, on peut citer le n-hexyle, n-octyle, n-éthylhexyle, diméthylhexyle, n-décyle, diméthyloctyle, triméthylheptyle, triméthylnonyle.
• - les mono- ou diesters de l'acide orthophosphorique ou l'un de ses sels, polyoxyéthylénés qui peuvent être représentés pour les phosphates d'alcoyle polyoxyéthylénés par la formule:
  
  et pour les phosphates de dialcoyle polyoxyéthylénés par la formule:
  
  dans lesquelles le radical R₇ représente un radical alcoyle linéaire ou ramifié ayant de 6 à 12 atomes de carbone, un radical phényle, un radical alcoylphényle avec une chaîne alcoyle ayant de 8 à 12 atomes de carbone, n₃ est le nombre d'oxyde d'éthylène pouvant varier de 2 à 8 et M₂ ayant la signification donnée précédemment. Comme exemples de radical R₇, on peut nommer le radical hexyle, octyle, décyle, dodécyle, nonylphényle.

As examples of anionic surfactants which can be used, mention may be made of:

• - soaps of alkali metals such as sodium or potassium salts of saturated or unsaturated fatty acids having from 8 to 24 carbon atoms and preferably from 14 to 20 or derivatives of aminocarboxylic acids such as sodium N-lauryl sarconisate, sodium N-acylsarconisate.
• - alkaline sulfonates such as alkylsulfonates, arylsulfonates or alkylarylsulfonates; in particular the alkylbenzenesulfonates of formula R ₁ -C ₆ H ₄ -SO ₃ M ₁ in which the radical R, is a linear or branched alkyl radical containing from 8 to 13 carbon atoms such as for example a nonyl, dodecyl, tridecyl radical and M ₁ represents a sodium or potassium atom, an ammonium radical, diethanolamine or triethanolamine; alkylnaphthalenesulfonates such as sodium nonylnaphthalenesulfonate. Other sulfonates can be used such as N-acyl, N-alkylltaurates of formula R ₂ -CO-N (R2 ') - CH ₂ -CH ₂ -SO ₃ Na where R ₂ is an alkyl radical having from 11 to 18 carbon atoms and R ₂ 'is a methyl, ethyl radical: for example N-oleoyl, N-methyltaurate or N-palmitoyl, N-methyltaurate sodium.
• - β-sulfoethyl esters of fatty acids, for example lauric, myristic, stearic acids: olefino-sulfonates containing from 12 to 24 carbon atoms, obtained by sulfonation using a-olefin sulfuric anhydride such as dodecene-1, tetradecene-1, hexadecene-1, octadecene-1, eicosene-1, tetracosene-1.
• - sulfates and sulfated products; among the alkyl sulfates corresponding to the formula R ₃ OSO ₃ M ₁ , mention may be made of those in which the radical R ₃ is a lauryl, cetyl, myristyl and M ₁ radical having the meaning given above; natural sulfated oils and fats; the disodium salt of sulfated oleic acid; polyoxyethylenated and sulphated fatty alcohols of formula:
  
  in which the radical R ₄ is an alkyl radical containing from 6 to 16 carbon atoms such as for example a myristyl radical or a linear or branched alkyl radical such as for example a hexyl, octyl, decyl, dodecyl radical, n, is the number moles of ethylene oxide which may vary from 1 to 4 and M _t having the meaning given above; polyoxyethylenated and sulphated alkylphenols of formula:
  
  in which the radical R ₅ is a linear or branched alkyl radical containing from 8 to 13 carbon atoms such as for example an octyl, nonyl, dodecyl radical, n ₂ is the number of moles of ethylene oxide which can vary from 1 to 6 and M ₁ having the meaning given above.
• - the primary and secondary esters of orthophosphoric acid or one of its salts which can be represented for the alkyl phosphates by the formula (R ₆ 0) PO (OM ₂ ) ₂ and for the dialkyl phosphates by the formula (R ₆ 0) ₂ PO (OM ₂ ) in which the radical R ₆ is a linear or branched alkyl radical containing from 6 to 12 carbon atoms and M ₂ represents a hydrogen, sodium or potassium atom. As examples of radical R ₆ , there may be mentioned n-hexyl, n-octyl, n-ethylhexyl, dimethylhexyl, n-decyl, dimethyloctyl, trimethylheptyl, trimethylnonyl.
• - the mono- or diesters of orthophosphoric acid or one of its polyoxyethylenated salts which can be represented for the polyoxyethylenated alkyl phosphates by the formula:
  
  and for dialkyl phosphates polyoxyethylenated by the formula:
  
  in which the radical R ₇ represents a linear or branched alkyl radical having from 6 to 12 carbon atoms, a phenyl radical, an alkylphenyl radical with an alkyl chain having from 8 to 12 carbon atoms, n ₃ is the number of oxides ethylene which can vary from 2 to 8 and M ₂ having the meaning given above. As examples of radical R ₇ , the radical hexyl, octyl, decyl, dodecyl, nonylphenyl can be named.

• - les alcoylphénols polyoxyéthylénés par exemple les produits de condensation d'oxyde d'éthylène à raison de 5 à 25 moles par mole d'alcoylphénol, le radical alcoyle étant droit ou ramifié et contenant de 6 à 12 atomes de carbone. On peut citer tout particulièrement le nonylphénol condensé avec environ 10 à 30 moles d'oxyde d'éthylène par mole de phénol, le dinonylphénol condensé avec 15 moles d'oxyde d'éthylène par mole de phénol, le dodécylphénol condensé avec 12 moles d'oxyde d'éthylène par mole de phénol.
• - les alcools aliphatiques polyoxyéthylénés résultant de la condensation avec l'oxyde d'éthylène à raison de 5 à 30 moles d'oxyde d'éthylène, d'alcools gras linéaires ou ramifiés contenant de 8 à 22 atomes de carbone: par exemple le produit de condensation d'environ 15 moles d'oxyde d'éthylène avec 1 mole de tridécanol ou d'alcool de coprah: l'alcool myristylique condensé avec 10 moles d'oxyde d'éthylène.
• - les amides carboxyliques tels que par exemple le diéthanolamide d'acides gras éventuellement polyoxyéthylènes comme l'acide laurique ou de l'huile de coco.
• - les alcools polyoxyéthylénés et polyoxypropylénés; une illustration de ce type de tensio-actifs sont les produits bien connus vendus sous la marque "PLURONICS". On les obtient à partir de polypropylèneglycols eux-mêmes insolubles dans l'eau ou à partir d'alcools aliphatiques inférieurs contenant de 1 à 8, de préférence de 3 à 6 atomes de carbone, que l'on a condensé avec de l'oxyde de propylène et qui sont aussi insolubles dans l'eau. Ces dérivés insolubles dans l'eau de l'oxyde de propylène sont rendus solubles par réaction avec l'oxyde d'éthylène.

As non-ionic surfactants, use may generally be made of compounds obtained by condensation of alkylene oxide with an organic compound which may be aliphatic or alkyllaromatic. Suitable nonionic surfactants are:

• - Polyoxyethylenated alkylphenols, for example ethylene oxide condensation products at a rate of 5 to 25 moles per mole of alkylphenol, the alkyl radical being straight or branched and containing from 6 to 12 carbon atoms. Mention may very particularly be made of nonylphenol condensed with approximately 10 to 30 moles of ethylene oxide per mole of phenol, dinonylphenol condensed with 15 moles of ethylene oxide per mole of phenol, dodecylphenol condensed with 12 moles of ethylene oxide per mole of phenol.
• - polyoxyethylenated aliphatic alcohols resulting from condensation with ethylene oxide at a rate of 5 to 30 moles of ethylene oxide, of linear or branched fatty alcohols containing from 8 to 22 carbon atoms: for example the product condensation of approximately 15 moles of ethylene oxide with 1 mole of tridecanol or coconut alcohol: myristyl alcohol condensed with 10 moles of ethylene oxide.
• - carboxylic amides such as for example the diethanolamide of fatty acids optionally polyoxyethylene such as lauric acid or coconut oil.
• - polyoxyethylenated and polyoxypropylenated alcohols; an illustration of this type of surfactants are the well known products sold under the brand "PLURONICS". They are obtained from polypropylene glycols which are themselves insoluble in water or from lower aliphatic alcohols containing from 1 to 8, preferably from 3 to 6 carbon atoms, which have been condensed with oxide. propylene and which are also insoluble in water. These water-insoluble propylene oxide derivatives are made soluble by reaction with ethylene oxide.

As cationic agents, diamines such as those of the type R _a NH C ₂ H ₄ NH ₂ in which R ₈ is an alkyl radical containing from 12 to 22 carbon atoms, for example N-, can be used. 2-aminoethyl stearyline and 2-aminoethyl-2 myristylamine; amidoamines such as those of the Rg CO NH C ₂ H ₄ NH _{2 type} in which Rg is an alkyl radical containing from 9 to 20 carbon atoms, for example N-aminoethyl-2 stearylamide and N-aminoethyl-2 myristylamide : quaternary ammonium compounds in which, in particular, one of the radicals attached to the nitrogen atom is an alkyl radical of 1 to 3 carbon atoms, including these alkyl radicals of 1 to 3 carbon atoms bearing inert substituents, for example halogen, acetate, methylsulfate, etc. As representative examples of surfactants of the quaternary ammonium type, mention will be made of: ethyldimethylstearylammonium chloride, benzyldimethylstearylammonium chloride, benzyldiethylstearylammonium chloride, trimethylstearylammonium chloride , trimethylketylammonium bromide, dimethylethyldilaurylammonium chloride, dimethylpropylmyristylammonium chloride, as well as the corresponding methylsulfates and acetates.

les alcoylamidopropyldiméthylbétaînes de formule:

les alcoyltriméthylsulfobétaines de formule:

dans lesdites formules n4 est compris entre 9 et 16.Finally, it is possible to use amphoteric surfactants such as alkyl dimethyl betaines of formula:

the alkylamidopropyldimethylbetaines of formula:

the alkyltrimethylsulfobetaines of formula:

in said formulas n4 is between 9 and 16.

The various anionic, nonionic, cationic, amphoteric surfactants listed above without limitation can be used alone or as a mixture.

Among the above-mentioned surfactants, sodium alkyl benzenesulfonates, sodium stearate, fatty alcohol sulfates, polyoxyethylenated fatty alcohol sulfates and polyoxyethylenated fatty alcohols, alcohols polyoxyethylenated and polyoxypropylenated fats, are very particularly suitable and are used in a preferred manner in detergent compositions.

The detergent compositions may also contain builders, one of the functions of which is to sequester the calcium and magnesium ions present in the water.

As examples of alkaline adjuvant salts which can be used in this function, mention may be made of carbonates, silicates, phosphates and polyphosphates. More specifically, mention will be made of sodium triphosphate, sodium and potassium pyrophosphate, sodium orthophosphate.

As builders, natural alumina silicates or those containing alumina, such as bentonite or vermiculite, are also suitable; synthetic zeolites of type A.

• - les acides aminopolycarboxyliques mis en oeuvre de préférence sous forme de sels alcalins, généralement sous forme de sels de sodium. On citera comme exemples, l'acide nitrilotriacétique, l'acide éthylènediaminetétraacétique l'acide N-hydroxyéthyléthylènediaminetriacétique. Conviennent également l'acide diéthylènetriaminepentaacétique et les homologues supérieurs des acides aminopolycarboxyliques mentionnés. Dans l'ensemble des composés précités, on préfère utiliser l'acide éthylènediaminetétraacétique (E. D. T. A) et l'acide diéthylènetriaminepentaacétique (D. T. P. A).
• - les acides hydroxycarboxyliques éventuellement sous forme saline d'acides tels que l'acide citrique, tartrique, gluconique, saccharique,
• - l'oxydiacétate de sodium,
• - les acides phosphoniques mis en jeu préférentiellement sous forme de sels alcalins, généralement sous forme de sels de sodium ou de potassium. On peut utiliser les acides disphosphoniques et polyphosphoniques répondant aux formules suivantes (I) à (V):
  
  
  
  
  
  dans lesquelles R,_o désigne un radical alcoyle et R" un radical alcoylène ayant de 1 à 8 et de préférence 1 à 4 atomes de carbone; X et Z représentent un atome d'hydrogène ou un radical alcoyle ayant de 1 à 4 atomes de carbone et Y désigne l'un des groupements suivants -OH, -NH₂ ou -NXR,_o.

It is also possible to use organic alkaline adjuvant salts such as:

• - Aminopolycarboxylic acids preferably used in the form of alkaline salts, generally in the form of sodium salts. Examples that may be mentioned are nitrilotriacetic acid, ethylenediaminetetraacetic acid, N-hydroxyethylethylenediaminetriacetic acid. Also suitable are diethylenetriaminepentaacetic acid and the higher counterparts of the aminopolycarboxylic acids mentioned. In all of the above-mentioned compounds, it is preferred to use ethylenediaminetetraacetic acid (EDT A) and diethylenetriaminepentaacetic acid (DTP A).
• hydroxycarboxylic acids optionally in the saline form of acids such as citric, tartaric, gluconic, saccharic acid,
• - sodium oxidiacetate,
• - The phosphonic acids preferably used in the form of alkaline salts, generally in the form of sodium or potassium salts. Disphosphonic and polyphosphonic acids corresponding to the following formulas (I) to (V) can be used:
  
  
  
  
  
  in which R, _o denotes an alkyl radical and R "an alkylene radical having from 1 to 8 and preferably 1 to 4 carbon atoms; X and Z represent a hydrogen atom or an alkyl radical having from 1 to 4 atoms carbon and Y denotes one of the following groups -OH, -NH ₂ or -NXR, _o .

dans laquelle n_o représente un nombre de 1 à 4.It is also possible to use a phosphonic acid corresponding to the following formula (VI):

wherein n _o is a number from 1 to 4.

Other suitable examples of phosphonic acids are described in French patent 2,437,442.

The following phosphonic acids are preferably chosen: amino tri (methylenephosphonic) acid: (ATMP) ethylenediamine-tetra (methylenephosphonic) acid: (EDTMP), diethylenetriamine-penta acid (methylenephosphonic) : (DTPMP).

The builders named above can be used alone but preferably in a mixture. Preferably, sodium disilicate, sodium carbonate, sodium orthophosphate, sodium pyrophosphate, sodium triphosphate, the sodium salt of nitrilotriacetic acid are chosen.

Detergent compositions generally contain, in addition to surfactants and builders, a certain number of conventional additives in variable quantity. Examples of these ingredients are (for example) agents for controlling foam such as polysiloxanes; mineral salts such as sodium sulfate; bleaching agents such as hydrogen peroxide and its hydrates, peroxides and persalts alone or in admixture with bleaching precursors and other anti-redeposition agents such as carboxymethylcellulose, carboxymethylhydroxyethylcellulose, polyvinyl alcohol, copolymers of maleic acid and vinyl ether, acrylic acid alone or copolymerized with vinyl monomers and water-soluble sulfonated polyesters, water-soluble polyester polyurethanes; fluorescent agents such as stilbenes, furans, thiophenes as well as small amounts of perfume, dyes and enzymes.

The bleach activator granules are introduced into the detergent compositions in an amount such that there is approximately 1 to 10% by weight of tetraacetylethylenediamine and preferably 2 to 4%.

The compound is added to the detergent compositions in an amount of 5 to 35% by weight, preferably 10 to 20%.

The weight ratio between tetraacetylethylenediamine and the compound can range from 2/3 to 1/35 and preferably from 1/2 to 1/20.

The detergent compositions contain at least 5 to 50% by weight of an anionic, nonionic, cationic, amphoteric surfactant in their mixtures and from 10 to 60% by weight of a builder. Preferably, 5 to 25% by weight of an anionic, nonionic surfactant or mixtures thereof and 10 to 40% by weight of a builder are added to the detergent compositions.

Below, examples of detergent compositions are given by way of illustration, but not limitation, into which the bleaching granules of the invention may be introduced. The percentages given are expressed by weight.

Detergent composition (1)

• - linear alkylbenzene sulfonate 6.2 (the alkyl radical containing about 12 carbons)
• - natural tallow soap 4.4
• - fatty alcohol containing 18 carbons and bearing 11 ethylene oxide units 3.2
• - sodium triphosphate 41.3
• - sodium sulfate 12.7
• - sodium perborate 23.2
• - carboxymethylcellulose 0.5
• - humidity 8.5

Detergent composition (2)

• - fatty alcohol containing 14 carbons and bearing 7 ethylene oxide units 11
• - sodium orthophosphate 4
• - sodium pyrophosphate 10
• - sodium triphosphate 26
• - sodium disilicate 8
• - sodium sulfate 13
• - sodium perborate 20
• - carboxymethylcellulose 0.5
• - foam regulating agent (polymethylsiloxane) 0.5
• - humidity 7

Detergent composition (3)

• - linear alkyl benzene sulfonate 11 ~ (the alkyl radical containing about 12 carbons)
• - coconut fatty acid soap 10
• - sodium triphosphate 35
• - sodium disilicate 5
• - sodium sulfate 5
• - sodium perborate 20
• - enzyme 1
• - humidity 13

Detergent composition (4)

• - linear alkylbenzene sulfonate 13.5 (the alkyl radical containing about 12 carbons)
• - sodium stearate 1.3
• - fatty alcohol containing 18 carbons and bearing 11 ethylene oxide units 3.7
• - sodium orthophosphate 0.9
• - sodium pyrophosphate 5.8
• - sodium triphosphate 26.5
• - sodium disilicate 4.5
• - sodium carbonate 0.6
• - sodium sulfate 8
• - sodium perborate 25
• - humidity 10.2

Detergent composition (5)

• - linear alkylbenzene sulfonate 9.2 (the alkyl radical containing about 12 carbons)
• - sodium stearate 6.7
• - fatty alcohol containing 18 carbons and bearing 11 ethylene oxide units 4.8
• - sodium orthophosphate 1.1
• - sodium pyrophosphate 3,4
• - sodium triphosphate 30.2
• - sodium disilicate 6.6
• - sodium carbonate 1,2
• - sodium sulfate 14.2
• - sodium perborate 11.4
• - humidity 11.2

The granules of the invention have an excellent resistance to storage in detergent compositions: the tetraacetylethylenediamine is effectively preserved from the other components of the detergent composition which would risk degrading it.

Detergent compositions containing the bleach activator granules according to the invention suitable for washing articles of all kinds based on natural, synthetic or artificial fibers and more particularly for washing textile materials based on natural fibers such as cotton optionally mixed with other fibers, in particular polyester.

The concentration of bleach granules in the washing bath expressed by weight of tetraacetylethylenediamine is such that there are between 0.05 and 1.00 g per liter of aqueous bath. The upper bound is obviously not critical, but it is preferable to choose a concentration between 0.1 and 0.3 g / I because higher concentrations do not bring any advantage in terms of the efficacy of the products. the invention.

The temperature of the aqueous medium which is used during washing is not critical in the sense that the bleaching granules behave effectively at temperatures ranging from about 20 to 100 ° C and preferably from 30 to 60 ° vs.

It should be noted that the washing is preferably carried out at low temperature due to the presence of tetraacetylethylenediamine, all the more so since the speed of dissolution of the coated tetraacetylethylenediamine granules is greater than the speed of dissolution of tetraacetylethylenediamine alone which makes it possible to quickly obtain the ions of peracetic acid and then the active oxygen allowing the bleaching effect to be obtained.

The present invention is illustrated in a nonlimiting manner by examples of preparation of the granules of the invention.

These granules are subjected to the following tests which demonstrate their physicochemical properties and their bleaching efficiency when they are introduced into a detergent composition.

Examples

• - tétraacétyléthylènediamine 74,5 %
• - triphosphate de sodium anhydre 23 %
• - carboxyméthylcellulose de sodium 2,5 %

1) Preparation of granules of the invention having the following composition by weight: the percentages are expressed by weight of dry matter.

• - tetraacetylethylenediamine 74.5%
• - anhydrous sodium triphosphate 23%
• - sodium carboxymethylcellulose 2.5%

In the examples which follow, granules are prepared having the composition by weight given above, but by using tetraacetylethylenediamine and sodium triphosphate of different particle size: the particle size of sodium triphosphate is always substantially finer than that of tetraacetylethylenediamine.

The granules are prepared according to the following procedure:

Example 1

• - la tétraacétyléthylènediamine mise en jeu à un diamètre moyen de particules de 0,130 mm et ne contient aucune particule de diamètre supérieur à 0,300 mm;
• - le triphosphate de sodium a un diamètre moyen de particules amené à 0,06 mm par broyage.

The powder mixture of tetraacetylethylenediamine and sodium triphosphate is first prepared:

• - the tetraacetylethylenediamine used with an average particle diameter of 0.130 mm and does not contain any particle with a diameter greater than 0.300 mm;
• - sodium triphosphate has an average particle diameter brought to 0.06 mm by grinding.

The dry mixing of 7.5 kg of tetraacetylethylenediamine and 2.5 kg of sodium triphosphate is carried out in a Y-rotating mixer: the operation lasts 15 minutes.

10 kg of this dry mixture are introduced into a 1 m diameter bezel, the stainless steel bowl of which is rotated by 25 revolutions per minute.

In addition, 5 liters of sodium carboxymethylcellulose solution (BLANOSE BWS) ® at 5% by weight are prepared which are brought to a temperature of 50 ° C.: the viscosity of the sodium carboxymethylcellulose used is 0.12 Pa. s, when measured at 50 ° C in 5% solution with a shear viscometer (RHEOMAT 15) ⁰ - the speed gradient used is 43 s- ^1.

This solution is sprayed on the dry mixture moving in the bezel.

The sodium carboxymethylcellulose solution is sprayed using a spray nozzle under a pressure of 4 bars, onto the powder mixture of tetraacetylethylenediamine and sodium triphosphate for a period of approximately 30 minutes.

Granules having the composition given above, of dry appearance and relatively solid, are extracted from the bezel.

The granules obtained are passed through sieves with a mesh opening of 0.63 mm and 2.00 mm.

• - fraction inférieure à 0,63 mm 13,6%
• - fraction comprise entre 0,63 et 2,00 mm 70,9 %
• - fraction supérieure à 2,00 mm 15,5 %

The following particle size distribution is obtained:

• - fraction less than 0.63 mm 13.6%
• - fraction between 0.63 and 2.00 mm 70.9%
• - fraction greater than 2.00 mm 15.5%

Example 2

• - la tétraacétyléthylènediamine est sous la forme d'une poudre broyée dont le diamètre moyen des particules est égal à 0,050 mm, qui ne contient aucune particule de diamètre supérieur à 0,300 mm et moins de 5 % de particules de diamètre inférieur à 0,010 mm.
• - le triphosphate de sodium est également broyé jusqu'à obtention de particules d'un diamètre moyen de 0,030 mm et ne contient aucune particule de diamètre supérieur à 0,060 mm.

In this example, granules having the same weight composition as given above are prepared from tetraacetylethylenediamine and sodium triphosphate having the following characteristics:

• - Tetraacetylethylenediamine is in the form of a ground powder whose average particle diameter is equal to 0.050 mm, which contains no particle with a diameter greater than 0.300 mm and less than 5% of particles with a diameter less than 0.010 mm.
• - the sodium triphosphate is also ground until particles of an average diameter of 0.030 mm are obtained and does not contain any particle of diameter greater than 0.060 mm.

The other conditions are identical to those of Example 1.

• - fraction inférieure à 0,63 mm 8,2 %
• - fraction comprise entre 0,63 et 2,00 mm 75 %
• - fraction supérieure à 2,00 mm 16,3 %

Granules with the following particle size distribution are obtained:

• - fraction less than 0.63 mm 8.2%
• - fraction between 0.63 and 2.00 mm 75%
• - fraction greater than 2.00 mm 16.3%

Example 3

The mode of preparation of the granules described in example 1 is reproduced, with the difference that tetraacetylethylenediamine having a mean particle diameter of 0.180 mm and containing no particle of diameter greater than 0.300 mm is used.

• - fraction inférieure à 0,63 mm 15,5 %
• - fraction comprise entre 0,63 et 2,00 mm 73,5 %
• - fraction supérieure à 2,00 mm 11 %

Granules with the following particle size distribution are obtained:

• - fraction less than 0.63 mm 15.5%
• - fraction between 0.63 and 2.00 mm 73.5%
• - fraction greater than 2.00 mm 11%

2) Physico-chemical properties of the granules of the invention

The granules prepared according to examples 1 to 3 are subjected to a series of measurements and tests in order to demonstrate their physicochemical properties. In the various tests, the particle size fraction of 0.63 to 2.00 mm is used.

a) Bulk density

The weight of 1 cm ³ of granules is determined by the weighing of 100 cm ³ of packed and loose packed granules.

The results obtained are as follows:

b) Solidity of the granules

The granules are subjected to a mechanical treatment then their solidity is evaluated by determining the percentage of fine particles formed by sieving through a sieve whose mesh opening is equal to 2/3 of the diameter of the smallest granule.

Mechanical manipulation consists of putting 200 g of granules in a 2-liter glass bottle and rotating it 40 revolutions per minute for 1 hour.

The percentage of "finished" is measured by passage through a standard AFNOR ^O sieve with a mesh size of 0.4 mm.

The percentages of "fines" obtained show that the granules are solid since only a very small part is deteriorated.

c) Kinetics of release of tetraacetylethylenediamine

This test makes it possible to evaluate the rate of formation of peracetic acid and to verify the absence of insolubles after total "perhydrolysis and hydrolysis" of tetraacetylethylenediamine.

The peracetic and acetic acids formed by perhydrolysis and hydrolysis of the liberated tetraacetylethylenediamine are neutralized so as to keep the pH constant at 10.

A test is carried out for comparison, in which the tetraacetylethylenediamine is not coated: the tetraacetylethylenediamine used, has an average particle diameter of 0.130 mm, 0.050 mm and 0.180 mm, that is to say, the same particle size as that introduced into the granules to be tested.

The half-reaction times (t1 / 2) corresponding to the formation of half of the amounts of peracetic and acetic acids are then determined, relative to the amount of tetraacetylethylenediamine introduced.

In a practical manner, a 1.58 g / l solution of sodium perborate tetrahydrate is prepared which gives a pH of 10.

About exactly 0.5 g / l of tetraacetylethylenediamine is added at a temperature maintained constant (25 ° C. and 50 ° C.) in the case of the comparative test or the corresponding quantity of granules during the test of the products of the invention.

0.5N sodium hydroxide is then added so as to maintain the pH at 10.

The quantities of peracetic and acetic acids formed are thus measured.

The following half-reaction times are determined: (the half-reaction times are expressed in minutes):

There is a marked improvement at low temperature in the rate of acid formation showing rapid release of the tetraacetylethylenediamine crystals.

In addition, it is found that there are no insolubles after hydrolysis and total perhydrolysis.

d) Storage behavior

The main purpose of the coating being to protect tetraacetylethylenediamine, during storage, from the action of the other constituents of the detergent composition which are likely to cause its decomposition, we will demonstrate the resistance to storage of tetraacetylethylenediamine having different particle sizes and coated in the form of granules of the invention. By way of comparison, a test is carried out with uncoated tetraacetylethylenediamine having the same particle size as that introduced into the granules to be tested.

• - dodécylbenzène sulfonate de sodium (ERGANOL AT3)® 25 %
• - stéarate de sodium 3 %
• - alcool gras contenant 18 atomes de carbone et portant 12 motifs d'oxyde d'éthylène (CEMULSOL DB 6-18)®3 %
• - alcool gras contenant 18 atomes de carbone et portant 50 motifs d'oxyde d'éthylène (CEMULSOL DB 25-17)⁰ 2 %
• - triphosphate de sodium 27,5 %
• - pyrophosphate de sodium (neutre-anhydre) 0,5 %
• - orthophosphate de sodium (anhydre) 0,5 %
• - disilicate de sodium 8,6 %
• - carboxyméthylcellulose de sodium (BLANOSE B.W.S)@ 1,5%
• - dérivé de distyrylbiphényl (azurant optique TINOPAL)® 0,4 %
• - protéase alcaline (enzyme ESPERASE NOVO)® 0,3 %
• - perborate de sodium tétrahydraté 15 %
• - granulés de l'invention en quantité exprimée en tétraacétyléthylène diamine ou tétraacétyléthylènediamine sans enrobage 3 %
• - sulfate de sodium qsp 100 %

The granules of the invention or the uncoated tetraacetylethylenediamine are mixed with a detergent composition having the following formulation:

• - sodium dodecylbenzene sulfonate (ERGANOL AT3) ® 25%
• - sodium stearate 3%
• - fatty alcohol containing 18 carbon atoms and bearing 12 ethylene oxide units (CEMULSOL DB 6-18) ®3%
• - fatty alcohol containing 18 carbon atoms and bearing 50 ethylene oxide units (CEMULSOL DB 25-17) ⁰ 2%
• - sodium triphosphate 27.5%
• - sodium pyrophosphate (neutral-anhydrous) 0.5%
• - sodium orthophosphate (anhydrous) 0.5%
• - sodium disilicate 8.6%
• - sodium carboxymethylcellulose (BLANOSE BWS) @ 1.5%
• - distyrylbiphenyl derivative (optical brightener TINOPAL) ® 0.4%
• - alkaline protease (ESPERASE NOVO enzyme) ® 0.3%
• - sodium perborate tetrahydrate 15%
• - granules of the invention in quantity expressed as tetraacetylethylene diamine or tetraacetylethylenediamine without coating 3%
• - sodium sulfate qs 100%

The test is carried out on 10 samples of 1 g of the detergent composition defined above containing either the granules of coated tetraacetylethylenediamine, or uncoated tetraacetylethylenediamine which is placed in a powder compact itself placed open in a packet of detergent so as to restore the usual conditions for storing detergents. Storage is carried out at 40 ° C in an atmosphere containing 80% relative humidity.

At the end of storage periods of 8, 18 and 43 days, the samples are withdrawn and the tetraacetylethylenediamine is assayed in the presence of all the components of the detergent composition and then the loss of activity of the tetraacetylethylenediamine is determined.

The principle of the method consists in measuring the peracetic acid formed by perhydrolysis of the residual tetraacetylethylenediamine, in basic medium. The peracetic acid formed in the presence of potassium iodide will oxidize it and the released iodine will be determined by a titrated solution of sodium thiosulfate.

• On commence par piler le contenu des poudriers au fond d'un mortier puis on procède à sa dissolution en ajoutant 15 cm³ de diméthylformamide et en agitant vigoureusement le mélange obtenu pendant 20 minutes.

The test protocol is set out below:

• We start by pounding the contents of the compacts at the bottom of a mortar then we proceed to its dissolution by adding 15 cm ³ of dimethylformamide and vigorously agitating the mixture obtained for 20 minutes.

To the suspension obtained, 80 cm ³ of a 0.15 g / l solution of ethylenediaminetetra (methylenephosphonate) of hexapotassium sold under the brand Dequest 2044 are added.

The mixture is left, with stirring, for exactly 5 minutes.

Then, the mixture is quickly and quantitatively transferred into a beaker containing 100 g of crushed ice and 10 cm ³ of glacial acetic acid.

About 1 g of potassium iodide is then added and the released iodine is assayed with a titrated solution of 0.1 N sodium thiosulfate in the presence of starch paste.

The results obtained are as follows: the loss of activity is expressed as a percentage of the initial activity:

It emerges from the analysis of this table, that the granules of the invention have a very good storage behavior and the tetraacetylethylenediamine contained in the granules is therefore effectively protected against the other constituents of the detergent composition.

3) Detergency test

In this test, we will follow the behavior of the granules of the invention, during washing, to see if they do not adversely affect the bleaching.

Standard soiled fabrics are used with colored stains therefore sensitive to bleaching: "wine" stain or "tea" stain deposited on cotton test tubes of dimensions = 10 _{x 12} cm (fabrics from the St Gall laboratory).

We measure the reflectance of soiled fabrics, before washing on a GARDNER ^S (GARDNER INSTRUMENTS) device.

The soiled cotton test pieces are washed in a device sold under the brand LINI-TEST (ORIGINAL HANAU) ^O which simulates a washing cycle at 60 ° C for 20 minutes.

Is introduced into each pot 4 cotton test tubes and 300 cm ³ of the detergent composition defined for the tests of resistance to storage at a rate of 8 g / l.

After washing, the test pieces are dried in the open air and then measured again with the GARDNER ^O reflectometer ^.

The bleaching efficiency is given by the variation in reflectance before and after washing.

The following results are obtained:

It is therefore noted that the coating agent and the particle size of the tetraacetylethylenediamine used in the bleaching granules of the invention do not induce any appreciable lowering of the bleaching efficiency compared to uncoated activator; moreover, it is noted that very good whitening performance is always obtained whatever the particle size of the tetraacetylethylenediamine chosen from the range defined according to the invention.

In conclusion, an advantage of the present invention is to have a flexible method for manufacturing granules with a high tetraacetylethylenediamine content greater than 55% by weight which makes it possible to granulate and coat any type of tetraacethylenediamine with a particle size included between 0.02 and 0.25 mm while still leading to granules having good storage behavior and good bleaching efficiency.

Claims (17)

1. Bleaching granules, characterised in that they are composed of a mixture of: tetraacetylethylenediamine and alkali metal triphosphate coated with an alkali metal derivative of cellulose and in that they contain 55 to 90 % by weight of tetraacetylethylenediamine and 10 to 45 % by weight of the mixture of alkali metal triphosphate and alkali metal derivative of cellulose.

2. Granules according to Claim 1, characterised in that they comprise sodium triphosphate in an amount such that its weight ratio to the amount of tetraacetylethylenediamine employed varies from 1/10 to 1/1, preferably from 1/4 to 2/3, and sodium carboxymethylcellulose in an amount such that its weight ratio to the amount of tetraacetylethylenediamine employed varies from 1/100 to 1/10, preferably from 1/30 to 1/15.

3. Granules according to one of Claims 1 to 2, characterised in that they comprise:

- from 60 to 75 % by weight of tetraacetylethylenediamine,

- at least 20 % by weight of sodium triphosphate,

- from 2 to 4 % by weight of sodium carboxymethylcellulose.

4. Granules according to one of Claims 1 to 3, characterised in that they have a diameter ranging from 0.4 to 2.0 mm, preferably from 0.6 to 1.2 mm.

5. Process for the preparation of bleaching granules, according to one of Claims 1 to 4, characterised in that it consists in producing a powder mix of tetraacetylethylenediamine and alkali metal triphosphate and in spraying a solution or a dispersion of an alkali metal derivative of cellulose onto a moving bed of this mixture.

6. Process according to Claim 5, characterised in that it consists in preparing the powder mix of tetraacetylethylenediamine and sodium triphosphate, in feeding the mixture obtained into a cylindrical-bowl coating apparatus, then in spraying a solution of sodium carboxymethylcellulose onto the mixture which is caused to move by the rotation of the coating apparatus, and finally in discharging the granules obtained.

7. Process according to one of Claims 5 or 6, characterised in that the tetraacetylethylenediamine has a particle size of between 0.02 and 0.25 mm, preferably between 0.05 and 0.15 mm.

8. Process according to one of Claims 5 and 6, characterised in that the sodium triphosphate has a particle size of between 0.02 and 0.08 mm.

9. Process according to Claim 6, characterised in that the charge, consisting of tetraacetylethylenediamine and sodium triphosphate, in the coating apparatus amounts to 30 to 100 kg/m³ of the coating apparatus, preferably to 40 to 80 kg/m³ of the coating apparatus.

10. Process according to one of Claims 6 and 9, characterised in that the speed of rotation of the coating apparatus is such that the tangential speed of the bowl of the coating apparatus is from 0.5 to 3 m/s, preferably from 1 to 2 m/s.

11. Process according to one of Claims 5 to 10, characterised in that it consists in preparing a solution of sodium carboxymethylcellulose, having a viscosity of less than 0.2 Pa - s, preferably between 0.10 and 0.15 Pa s, in keeping it at a temperature which is preferably between 30 and 80° C and then spraying it under a pressure of 2 to 10 bars, preferably of 4 to 5 bars, onto the moving powder mix of tetraacetylethylenediamine and sodium triphosphate.

12. Process according to one of Claims 6 to 11, characterised in that the mean residence time of the granules in the coating apparatus is from 10 to 60 minutes.

13. Process according to one of Claims 5 to 12, characterised in that the granules are screened and dried.

14. Detergent and bleaching compositions comprising at least one surfactant, a per-compound which liberates hydrogen peroxide in aqueous solution, a builder and optionally other conventional additives, characterised in that they comprise the bleaching granules, according to one of Claims 1 to 4.

15. Compositions according to Claim 14, characterised in that they comprise:

- from 5 to 50 % by weight of an anionic, non-ionic, cationic or amphoteric surfactant or mixtures of these,

- from 10 to 60 % by weight of a builder,

- from 5 to 35 % by weight of a per-compound which liberates hydrogen peroxide in aqueous solution,

- from 1 to 10 % by weight of tetraacetylethylenediamine in the form of bleaching granules according to one of Claims 1 to 4.

16. Compositions according to one of Claims 14 and 15, characterised in that they comprise:

- from 5 to 25 % by weight of an anionic or non-ionic surfactant or mixtures of these,

- from 10 to 40 % by weight of a builder,

- from 10 to 20 % by weight of a per-compound which liberates hydrogen peroxide in aqueous solution,

- from 2 to 4 % by weight of tetraacetylethylenediamine in the form of bleaching granules according to one of Claims 1 to 4.

17. Compositions according to one of Claims 14 to 16, characterised in that the per-compound which liberates hydrogen peroxide in aqueous solution is sodium perborate.