FR2552446A1 - LOW-PHOSPHATE GRANULAR DETERGENTS AND PROCESS FOR THEIR MANUFACTURE - Google Patents

Abstract

1. A method of preparing granular detergents with a low phosphate content, that is with a content of between 10% and 25% of sodium tripolyphosphate and a combined content of sodium orthophosphate and of sodium pyrophosphate of less than about 2% by weight and preferably less than about 1% by weight, and containing non-ionic surface active agents amounting to about 10% by weight of the whole composition, the method comprising forming an essentially hot aqueous suspension with thermostable constituents, drying the suspension in an atomising tower, mixing the atomised base with sodium tripolyphosphate and the other thermosensitive constituents, and then agglomerating the solid components by pulverisation with the assistance of a non-ionic surface active agent until there are obtained essentially homogeneous granules with little tendency to glutination, and the method being characterised in that the whole of the sodium tripolyphosphate is not subjected to the phases of hot aqueous suspension or atomisation, and in that, during the agglomeration phase, the temperature of the non-ionic surface active agent is between 25 degrees C and 80 degrees C, and preferably between 50 degrees C and 70 degrees C.

Description

The present invention relates to a method of manufacturing

  granular detergent compositions with reduced phosphates content and excellent qualities in washing textile fibers and in their physical characteristics of homogeneity, fluidity and density, without the need for use large amounts of additives

substituting for phosphates.

  The use in the granular compositions of salts which reinforce the detergent action, which is generally called "builders", is universally extended and is found to be indispensable for obtaining good results in laundry washing. The most widely used compound, Thanks to the excellent results obtained, it is undoubtedly the sodium tripolyphosphate (STPP). Unfortunately, its massive use in the manufacture of granular detergents is linked to an increase in the eutrophication in the waters of rivers, lakes and marshes. which is harmful to the ecological balance of the medium It is for this reason that, while one seeks to elucidate the true influence of phosphate from detergents in the problem envisaged, several countries have taken preventive measures limiting

  It uses phosphates soluble in detergents.

  To solve this problem, several solutions have been studied that can be classified into two groups. On the one hand, the use of alternative "builders" to replace phosphates, in part or in whole; This is the case with certain types of alkali aluminosilicates, such as those described in German Pat. No. 2,421,837. These builders, however, are not able to equal the excellent properties of phosphate by themselves, which is why detergent compositions containing them must be reinforced by additives which complement the complexing action on the calcium ions

  and magnesium or which improve the inhibitory properties of encrustation and redeposition of insoluble inorganic compounds on the tissues.

  On the other hand, an alternative is to formulate low phosphate content detergent compositions using a surfactant system which is rich in non-hard water-sensitive surfactants, such as those of the nonionic type, and to be strengthened. composition with additives such as those already mentioned This technique addresses two fundamental problems Firstly the nonionic surfactants of the type of alkoxylated alcohols having a low or average degree of alkylation, if they are the best Although they are suitable for detergent action, they do not withstand the conditions of atomization because, on the one hand, they undergo degradation due to oxidation and, on the other hand, they are evaporated and released into the atmosphere. This problem can be solved by spraying the nonionic surfactants on atomized bases with the other components and allowing them to penetrate the granules. This technique has created problems with regard to the fluidity of the final product and the limitation of the amounts of surfactant that can be absorbed by the granules. This technique has given rise to a large number of patents which have attempted to solve this problem, among which examples are the patents

  US 3,769,222, US 3,838,072, US 3,849,327 and US 4,006,110.

  The other problem that arises is the hydrolysis (reversion) that the sodium tripolyphosphate undergoes during the atomization process. It is known that during the atomization process the sodium tripolyphosphate partially hydrolyzes to orthophosphate and pyrophosphate. all precautions that can be surrounded, at least 10 to 15% of the tripolyphosphate will hydrolyze during atomization In the presence of high proportions of tripolyphosphate, this effect is of little importance In contrast, in Low phosphate content, ie in which the sodium tripolyphosphate is reduced to the smallest possible amount, this effect appears really negative, since apart from the fact that the amount of tripolyphos15 phate useful is reduced, orthophosphates and

  Pyrophosphates appear in the washing bath, and the formation of insoluble mineral salts which settle on the tissues give the latter a gray appearance.

  This effect can be corrected in part; by reinforcing the detergent composition with high amounts of additives which must inhibit the redeposition and encrustation of the mineral deposits on the fabrics, with consequent increase in the price of the final product.

  It has further been suggested, for example in European Patent Applications Nos. 090, 56, 563 and 9,952, the possibility of adding the tripolyphosphate to the detergent composition after the atomization process with a view to avoid hydrolysis as much as possible; this, however, creates problems of homogeneity and segregation during the agglomeration process, which also renders this technique unsuitable for making such compositions. It has also been envisaged as a solution, for example in British Patent No. 1,560,076,

  The addition to the aqueous suspension, prior to atomization, of a wax which reduces the degree of hydrolysis of the tripolyphosphate.

  The present invention relates to a process for obtaining granular detergent compositions which solves the problems in question, since it makes it possible to obtain homogeneous and fluidifiable granules, these compositions have a sodium tripolyphosphate content of less than about 25% by weight. are substantially free of orthophosphate and pyrophosphate and can contain up to about 10% by weight

nonionic surfactants.

  The main object of the invention is therefore to find a process for obtaining granular detergent compositions with a low tripolyphosphate content and high nonionic surfactant content, which have good conditions of homogeneity, fluidity and density. and excellent properties from the point of view of washing and

bleaching of textiles.

  Another object of the invention is to find a process for obtaining detergent compositions having a low phosphate content which would require small amounts of additives to improve the sequestering capacity of the ions responsible for the hardness of the water. In order to achieve this, it is another object of the invention to find a process for obtaining detergent compositions.

  low in phosphates at the lowest prices.

  The process of the invention consists essentially of forming a hot aqueous suspension with the thermostable components of the composition, wherein the suspension is dried in an atomization tower and the atomized base is mixed in one in a Suitable apparatus, sodium tripolyphosphate and other thermosensitive components of the composition After the mixing is carried out in the same apparatus by means of a nonionic surfactant spray, this component is added by The absorption of the surfactant occurs simultaneously with the agglomeration process which renders the product homogenous by giving granules which are not prone to segregation. After a certain time of maturation and when the nonionic surfactant has finished its absorption, the granules become fluid and do not show

  no tendency to agglutination.

  In this way, it is possible to surprisingly and unexpectedly increase the absorption capacity of nonionic surfactant, while preserving the good qualities of homogeneity and fluidity that must be achieved.

  granular detergent compositions.

  The fact that the tripolyphosphate does not pass through the aqueous suspension or the atomization phase prevents it from undergoing hydrolysis to orthophosphate and pyrophosphate, so that said products will appear only in the composition. finished detergent in very small amounts corresponding to those already contained in the sodium tripolyphosphate

  As a result, the tendency to form insoluble precipitates which, in incrustation, render the gray tissues considerably lessened in such a detergent composition.

  All this would not be sufficient in itself, since the mixture of the atomized base and the crystalline tripolyphosphate, because of its large differences in density and particle size, would tend to separate from the mass, producing poorly homogeneous compositions. In addition, this type of low phosphate composition needs to have higher proportions of nonionic surfactants than normal, which are less sensitive to water hardness; moreover, it is well known that, in general, tripolyphosphate atomized bases have little tendency to absorb such products, which are liquid or solid and have a low melting point, and which also tend to release 10 during the storage process a portion of the absorbed surfactant, giving a compact appearance to

  granules and oily stains on the containers.

  These problems are solved, according to the process of the invention, in a simple and inexpensive way, using as an ingredient for the agglomerate the nonionic surfactant itself which one wants to absorb; in this way not only homogeneous granules which become readily fluid, but surprisingly, make possible the integration of the nonionic surfactant in proportions of up to 10% of the total weight. of the composition, maintaining the good characteristics of the granules and a good

  stability of these during storage.

  This is accomplished by spraying the nonionic surfactant onto the atomized base mixture, tripolyphosphate, and thermosensitive components in a suitable apparatus which may be one in which the solids were blended, such as rotary drum or mixer of the "Lt-dige" type The temperature of the nonionic surfactant during the agglomeration process must be understood

  between 25 C and 80 C and preferably between 50 C and 70 C.

  The product thus prepared is put directly into the container and requires a maturation time so that the absorption process of the nonionic surfactant is completed, during which time the granules 5 acquire the necessary fluidity. This maturation time depends essentially on the characteristics of the atomized base, but is in no way greater than 24 hours. Figures 1 and 2 attached to assess the characteristics of the granules obtained

according to the method of the invention.

  Figure 1 shows the scanning-magnified 20-fold photographic micrograph of a group of granules in which their uniform appearance and size are observed, and their rare tendency

to clump together.

  FIG. 2 shows the scanning electron micrograph magnified 160 fold of an open granule where the agglomeration of the various components inside the granule is observed.

and the good cohesion of it.

  The process according to the invention makes it possible to obtain granular detergents for washing textiles, essentially corresponding to the following basic composition: from 1 to 12% by weight of anionic surfactants; from 2 to 10% by weight of nonionic surfactants; from 15 to 60% by weight of structural salts; from 5 to 20% by weight of alkaline salts; from 10 to 25% by weight of sodium tripolyphosphate of 1 to 30% by weight of whitening peroxides, and from 0 to 2% by weight of orthophosphate

  sodium and sodium pyrophosphate.

  The granules according to the invention may further contain other types of components, such as salts which enhance the detergent action, of organic or inorganic type, soluble or insoluble in water, foam controllers of different types. , bleaching activators of the peroxide precursor type, those with a sequestering action of the type of polyoxycarboxylic or phosphonic acids, polymers which inhibit incrustation and redeposition, whiteners

  optical, photoactivators, dyes, perfumes, and in general, any type of additives usually employed in detergents.

  The following is a more detailed description of the various types of components which can be incorporated into the granular detergents obtained according to the method of

The invention.

  Among the thermostable components, mention may be made of anionic surfactants, including in this group both alkaline soaps and synthetic anionic surfactants. Among the soaps, mention may be made of sodium, potassium and ammonium salts. alkanolammonium fatty acids which contain from 8 to 24 carbon atoms, of which the preferred are the sodium and potassium salts mixed with the fatty acids derived from the oil

  coconut, tallow, fish and rapeseed.

  Among the anionic surfactants that can be used in the present invention, mention may be made of the soluble salts of alkylbenzene sulfonates, alkyl sulphates, alkylpolyethoxyether sulphonates, α-olefin sulphonates and paraffin sulphonates. alkyl glyceryl ether sulfonates, sulfocarboxylates and esters thereof; fatty acid monoglyceride sulphates and sulphonates, alkyl phenol polyether sulphates, etc. Among these are the sodium and potassium alkylbenzene sulphonates whose alkyl chain is essentially linear and whose number of carbon atom is between 10 and 14. Of the thermostable components, polyoxyethylenated or polyoxypropylene fatty aliphatic surfactants having a high degree of oxidation can also be added in amounts of less than 2%. alkoxylation, i.e., with a number of moles of alkylene oxide per mole of fatty alcohol greater than 10 and whose fatty alcohols have linear or partially branched chains whose carbon number varies between Examples of such products are oxyethylenated tallow alcohol, oxyethylenated lauryl alcohol, and synthetic products commercially available under the trade names such as e Dobano I), Synperonic (Lutensor, etc.). It is also possible to incorporate cationic surfactants of the quaternary ammonium salt type, among which at least one or two of the alkyl radicals.

  are linear or partially branched C 8 -C 18 carbon chains.

  Among the amphoteric surfactants which may also be used are the water-soluble derivatives of aliphatic secondary and tertiary amines in which the aliphatic radical may be in a straight or branched chain, and among the water-soluble derivatives thereof. their substituents contain 8 to 18 carbon atoms and the other consists of a hydrophilic anionic group such as for example the groups

  carboxy, sulfonate, phosphate or phosphonate.

  It is also possible to use those called hybrid or zwitterionic ion surfactants, such as the water-soluble derivatives of quaternary, phosphoric and sulphonic cationic aliphatic compounds in which the radicals can be linear or branched and one of their aliphatic substituents contains from 8 to 18 carbon atoms and the other contains

  an anionic group that solubilizes in water.

  In the process of the invention, apart from the sodium tripolyphosphate which does not undergo the atomization phase and then mixes with the atomized base, other salts which reinforce the detergent action, which are thermostable and These salts which reinforce the detergent action, which are generally known as "builders", may be organic or inorganic. Among the mineral products, mention may be made by way of examples and without this being the case. The alkali metal salts, such as borates, alkali metal carbonates, and water-insoluble salts, may be exemplified by alkali aluminosilicates which act as ion exchangers for the purpose of the invention. Calcium ion and heavy metals, the most indicated being those called type A zeolites. Among the salts which reinforce the organic-type detergent action, mention may be made, for example, of the hydrosol salts. glycolic acid, water-soluble aminopolyacetates, of which sodium nitrilotriacetate is preferred, water-soluble polycarboxylates, such as lactic acid salts, phytic acid and its ether derivatives, citrates, maleates, carboxymethylsuccinates, etc. Alkaline polyphosphonates such as alkali metal salts of methylene-diphosphonic acid, ethylene diamine tetramethylene phosphonic acid and diethylene triamine pentamethylene phosphonic acid

are also appropriate.

  The organic and inorganic detergent enhancing salts can be used together in appropriate proportions.

  For a good realization of the atomization phase, it is necessary to use in proportions varying between 15 and 60% neutral structuring salts which confer on the atomized base a support necessary for obtaining consistent granules. sodium is particularly indicated

as structuring salt.

  In the range of thermostable components, an alkali metal silicate, in a proportion ranging between 3 and 13%, which has an SiO 2 / M molar ratio of between 1 and 4, and preferably between 1.5, may be added. and 2.5 (M denoting an alkali metal). To improve the suspension of the soil particles in the washing bath, it is possible to add amounts of between 0.1 and 5% of products such as water-soluble salts of carboxymethylcellulose, methylcellulose, carboxyhydroxymethylcellulose or else polyethyleneglycols whose molecular weights are

between 500 and 10,000.

  Other thermostable components which are present are polymers which give a better appearance to the washed laundry. In fact, they have an inhibitory action on the encrustation, that is to say they prevent insoluble mineral salts from forming. The polymers are water-soluble salts of polycarboxylic homo or co-polymers, the carboxylic groups of which are separated from each other by at least one or two carbon atoms. Such products are homo or copolymers having monomeric units, such as, for example, maleic anhydride, maleic acid, methyl vinyl ether, acrylic acid, methacrylic acid, etc. These products are found on the market under the name of Sokalan), Gantrez (, Prima®, etc. It is also possible to add foam controllers other than soaps or nonionic surfactants with a high degree of oxyte. thylenation such as, for example, waxes, saturated hydrocarbons, phosphoric acid esters and silicones. In this context, special silicones such as dialkylpolysiloxane combinations with finely divided silica and silane silicas or copolymers are preferred. These specialty silicones are marketed by the Dow-Corning Company under the US Pat.

  references Q 2-3092, DC-100, DC-190, DC-193, DC-198 These silicones can be added both in the atomization phase and in the mixing and agglomerating phase.

  and they can be used as they are by the supplier or be protected by granulation and by the fact that they are coated with inert materials to avoid their interaction with the alkaline components of the composition. Useful also can be added to the composition, in the atomized phase, fluorescent anionic brighteners which are also known as optical whiteners. Among these types of products, the most suitable are the water-soluble derivatives of stylbene sulphonates and the water-soluble derivatives of Distyrylbiphenylsulfonates There is a wide range of these products marketed by CIBA-GEIGY,

  among which there may be mentioned Tinopal (MS, Tinopal {15 DMS, Tinopal LMS-X and Tinopa CBS-X.

  Photoactivator products are also useful and can be added in the atomization phase; these are products which, in contact with light, decompose to produce oxygen which ensures better stain removal and improves the whiteness of the laundry. These products are soluble sulphonated phthalocyamines which maintain a metal cation in complex form, Among which zinc and aluminum are preferred. An example of this type of product is the Tinolux® sold by the Company.

Ciba-Geigy.

  All the components described so far can be incorporated in the initial solution which undergoes the atomization process, since, by their characteristics, they support the conditions of said process. However, this is not a necessary condition, since there is no disadvantage in adding some of them during the mixing and agglomeration phase. However, it is a necessary condition to add the components to the mixing phase. will be described later, since by their characteristics they undergo undesirable degradation processes during the aqueous suspension phase and the atomization. The sodium tripolyphosphate acts as a salt which enhances the main detergent of the composition. It is added to the composition during the mixing phase, to avoid partial hydrolysis thereof to pyrophosphate and orthophosphate, in proportions of less than 25%. Within the scope of the present invention, any type of commercially available sodium tripolyphosphate may be used, provided only that the total amount of orthophosphate and pyrophosphate remains below about 7%, preferably 5%, This represents a significant improvement over the prior art, for example illustrated by the patent application EP 9 952, in which it is essential to mix with the atomized base a tripolyphosphate with particular characteristics of water. particle size and hydrated before or after the mixing operation, which has the consequence that uence to increase the cost of both the raw material and the finished product and to make the implementation of the process

more complicated.

  In the group of thermosensitive components, the medium and low alkoxylation nonionic surfactants are very important, since among the nonionic surfactants they are the most effective from the point of view of

  detergent They may be of the type of the reaction product of linear or partial chain fatty alcohols-

  branched with a number of carbon atoms between 8 and 22, with a number of moles of ethylene oxide or propylene oxide of between 3 and 10, and preferably between 5 and 8 per mole of alcohol, or many alkylphenols whose alkyl radical contains a number of carbon atoms of between 7 and 11, with a number of moles of ethylene oxide or propylene oxide of between 7 and 12 per mole of phenol. It is easily found on the market under the name of Dobano I), Findet®, Symperonic I p etc. These nonionic surfactants are added in the agglomeration phase in proportions of between 2% and 10% and outside their surfactant action, they act as

  agglomerating material of the composition.

  During the mixing phase it is also possible to add enzymes which promote the action of the detergent, in the form of particles. These enzymes can be proteases or amylases and are on the market under the name Alcalase) Maxatase ( etc. The incorporation of whitening chemicals is also very suitable. These products are also heat-sensitive, which is why they must be added in the mixing phase, for example in proportions of between 1 and 30% by weight, and they may be to choose from peroxide salts such as sodium perborate sodium and tetrahydrate, sodium percarbonate, sodium persilicates and sodium perphosphates or from peroxyacids such as monoperoxyphthalic acid or its magnesium salt, diperisophthalic acid and diperazelaic acid and from

  organic peroxyacid precursors such as tetraacetyl ethylene diamine, tetraacetyl hexamethylene diamine, tetraacetyl methylene diamine, tetraacetyl-

  glycoryl and pentaacetylglucose The precursors of peroxyacids, also known as bleach activators, can be added in the crystalline state or in the form of granules with a protective covering to ensure storage stability. Finally, it is also possible to add another type of additive such as fluidizers which have an anti-mass action, for example sodium sulphosuccinate, sodium benzoate, sodium benzoate, silica gel and zeolites, as well as constituents such as perfumes, dyes and granules of

neck I eur.

  In the examples which follow, given by way of illustration only, the following references are used to identify the various components: C 1: Linear sodium alkylbenzene sulfonate CC 2: Blend of tallow soap and fish soap with 16 % of C 20 _C 22 20

C 3: sodium lauryl sulphate.

  C 4: Hostapur O-OS c-olefin-sulfonate from Hoechst.

  C 5: Hydrogenated tallow alcohol with 11 moles of ethylene oxide.

  C 6: Di- (hydrogenated tallow) -dimethylammonium chloride.

C 7: Anhydrous sodium sulphate.

  C 8: Sodium silicate with NA 20 / Sio 2 ratio

= 1: 2.

C 9: Sodium carbonate.

  C 10: A-type crystalline zeolite. Cll: Sodium Trilon Nitrile triacetate A powder

from BASF.

  C 12 Dequest) 2046 from Monsanto Ethylene diamine

  tetramethylene sodium phosphate.

  C 13: Gantrez% AN-119 Copolymer of poly (methyl

  vinyl ether / maleic anhydride).

C 14 Carboxymethyl cellulose.

  C Ethylene diamine tetraacetate sodium (EDTA).

  C 16 DC 100 Dow-Corning Polydimethylsiloxane

with silane silica.

  C 17: Tinopal (DMS from CIBA GEIGY Whitening

  optical type of stylbene-sulfonates.

  C 18 Tinolux (F of CIBA GEIGY Aluminum Phthalocyamine Sulfonate.

  C 19 Pentasodium tripolyphosphate prehydrated.

  Lial alcohol 145 with 8 moles of ethylene oxide.

C 21 Sodium perborate.

  C 22: tetraacetyl ethylene diamine (TAEB).

  C 23: Alcalass) from Nevo Industrie Proteolytic Enzyme.

  EXAMPLES I TO VI In Table I below, the compositions of several granular detergents obtained according to the following method were indicated: in a stirred mixer, an aqueous suspension of at least a portion of the C components is prepared therein The total amount of water must be between 20 and 40% of the total weight of the suspension and the temperature of the mixture must be between 55 ° C. and 75 ° C. Once the suspension is homogeneous, it is sprayed into a mixture. counter-current atomization tower, with a hot-air inlet temperature of between 300 ° C. and 370 ° C. and a gas outlet temperature of between 80 ° C. and 110 ° C. The resulting granules are cooled. The atomized base is introduced into a rotating drum and the components C 19, C 21, C 22 are added by means of a tremis. and C 23 Once the m Once the mixture is finished, it is sprayed thereon by means of a suitable nozzle component C 20 brought to a temperature of between 50 ° C. and 60 ° C. Then the granular composition is put directly into the appropriate containers for its consumption, and It is stored for 24 hours during which the product matures, i.e. at the total absorption of the nonionic surfactant and

  consequent to the fluidification of the granules.

  The data in Table I are expressed as percentages by weight of the final detergent composition.

TABLE I

15 20 25

  Cl C 2 C 3 C 4 C 5 C 6 C 7 C 8 C 9 C 10 O C 1 C C 13 C 14 C 15 C 16 C 17 C 18 C 19 C 20 C 21 C 22 C 23

I I II II IV V VI

lDnstituants

4.9 2.5

1.3 34.3 5.9

1.9 2.9 1, O 25.0 6.7

2.5 5.9 1.25 33.4 5.4

_ Ar I, U

1.9 2.5

  0.4 1.2 1.0 0.67 1.0 0.76 1.0 0.4 0.36 0:, 42 0.19

  0.19 0.19 0.13 0.005 0.003 19.6 15.0 19.2 3.4 6.7 4.2 21.5 17.1 18.4

0.9 1.0

0.15 0.17 0.2

, 6 2,3

0.93

26.7 4.7 5.7

0.94

2,3 0.47 0.07 0.19

23.7 5.6 14.0 1.9 0.3

3.5 2.5

1.0 1.25 23.1 6.0

u, 0

0.7 1, -31 0.79 0.26

0.18 0.004 15.7 6.0 13.4

0.16 6.2

28.0 5.8

4.4

0.9 1.1 0.27 0.3 0.14

, 0 8.0 21.3

0.18

__ 01 01

  In all these examples the composition is completed with water, perfume and dyes up to 100%.

Example VII

  In this example, the fluidity of the described granular detergent compositions is expressed and compared.

in Examples I to VI.

  The standard UNE -547-81 (Spain) which corresponds to International Standard I 50-4324-1977 was used as the criterion, in which the value in radians of the angle formed by the mound of granular material tested was determined. it is poured 10 by means of a funnel under the described conditions

in the standard.

  Measurements were taken after 24 hours, two weeks, and six weeks, respectively

after the preparation of the product.

  The results obtained are expressed in table II-below. The values of the angles expressed in radians in the table in question show

  that all products have a good fluidity.

  The good values are considered to be less than 0.5590, and as can be observed.

  all values expressed are satisfactory.

  We can even consider the majority of them

like slow excel.

  It is also observed that there are no significant losses of fluidity during the process.

storage.

TABLE II

Claims (1)

1 / Process for obtaining granular detergent compositions with a low phosphate content and a high content of nonionic surfactants, characterized in that an aqueous suspension is formed while hot with the thermostable constituents, and is dried In a spray tower, the atomized base is mixed with sodium tripolyphosphate and the thermosensitive constituents, and the solid components are then agglomerated by means of a spraying with the aid of a surfactant. nonionic active until substantially homogeneous granules and low tendency to agglutination. 2 / A method according to claim 1, characterized in that all the sodium tripolyphosphate does not undergo the aqueous suspension and atomization phases 3 / Method according to one of claims 1 and 2, characterized in that It ' detergent compositions with a sodium tripolyphosphate content of between 10% and 25% and a lower sodium orthophosphate and sodium pyrophosphate content together at about 2% by weight and preferably less than about 1% by weight.   4 / Method according to one of claims 1 to 3,   characterized in that it is possible to use sodium tripolyphosphate hydrate or not, and having any particle size.   / Method according to one of claims 1 to 4,   characterized in that the nonionic surfactant absorbed in the solid components acts as an agglomerating agent of   these, in addition to its detergent action. -23 2552446   6 / A method according to one of claims 1 to 5, characterized in that the nonionic surfactant used as agglomerating agent belongs to the group of alcohols   linear or partially branched CC fat C 8-C 22   polyoxyethylenated with a number of moles of ethylene oxide per mole of alcohol of between 3 and 10, and preferably between 5 and 8.   7 / A method according to one of claims 1 to 5, characterized in that the nonionic surfactant used as agglomerating agent belongs to the group of alkylphenols whose alkyl radical contains a number of carbon atoms between 7 and 11 with a number of moles of ethylene oxide per mole of phenol of between 7 and 12.   8 / A method according to one of claims 1 to 7, characterized in that it is added up to about 10% of   total weight of the nonionic surfactant composition, without losing the desirable characteristics of fluidity in the granules and maintaining said characteristics during storage.   9 / Method according to one of claims 1 to 8,   characterized in that, during the agglomeration phase, the temperature of the nonionic surfactant is to be understood   between 25 and 80 ° C and preferably between 50 and 70 ° C.   Granular detergent composition obtained by carrying out the method according to one of claims 1 to 9, characterized in that it essentially corresponds to the following basic composition.   from 1 to 12% by weight of anionic surfactants of 2 to 10% by weight of nonionic surfactants of 15 to 60% by weight of structural salts of 5 & 20% by weight of alkali metal salts; from 10 to 25% by weight of sodium tripolyphosphate; from 1 to 30% by weight of whitening peroxides, and from 0 to 2% by weight of sodium orthophosphate and sodium pyrophosphate.