EP1377368A1

EP1377368A1 - Suspension obtained from a multiple emulsion comprising a hydrophobic compound solid at room temperature and granules obtained by drying said suspension

Info

Publication number: EP1377368A1
Application number: EP02732810A
Authority: EP
Inventors: Hélène LANNIBOIS-DREAN; Anne-Ga[lle DRENO
Original assignee: Rhodia Chimie SAS
Current assignee: Rhodia Chimie SAS
Priority date: 2001-04-12
Filing date: 2002-04-11
Publication date: 2004-01-07
Also published as: FR2823450B1; FR2823450A1; JP2004535275A; WO2002083288A1; US20040127579A1

Abstract

The invention concerns a suspension of particles in an aqueous medium, obtainable by carrying out the following steps: (a) preparing an invert emulsion from an internal aqueous phase comprising at least an active hydrophilic substance, and an internal organic phase comprising at least a hydrophobic compound having a melting point not less than 35 DEG C, at least a non-ionic or cationic surfactant and/or at least a non-ionic or cationic amphiphilic polymer; the temperature for preparing the emulsion being not less than the melting point of the hydrophobic compound; (b) preparing the multiple emulsion by dispersing the invert emulsion in an external aqueous phase comprising at least a non-ionic polyalkoxylated surfactant and/or at least a non-ionic polyalkoxylated amphiphilic polymer and at least an anionic surfactant; the temperature for carrying out the dispersion being not less than the melting point of the hydrophobic compound; (c) bringing said resulting emulsion to a temperature not higher than the melting point of the hydrophobic compound. The invention also concerns granules obtainable by contacting said suspension with at least a drying agent. Finally, the invention further concerns the use of said suspension and said granules.

Description

SUSPENSION OBTAINED FROM A MULTIPLE EMULSION

COMPRISING A SOLID TEMPERATURE HYDROPHOBIC COMPOUND

AMBIENT AND GRANULES OBTAINED BY DRYING THE SUSPENSION

The subject of the present invention is a suspension capable of being obtained from a multiple emulsion, that is to say a reverse water-in-oil emulsion dispersed in an aqueous phase; the reverse emulsion comprising, as continuous organic phase, a hydrophobic compound which is solid at room temperature and which more particularly has a melting point greater than or equal to 35 ° C. It also relates to granules which can be obtained by drying said suspension, as well as the use of the suspension and granules.

Given the increasing number of formulations comprising several active ingredients, the problems linked to the compatibility of the active ingredients with each other have also increased.

In many fields, it is increasingly proposed to simplify the conditions of use of formulations by introducing into said formulations all the necessary ingredients, including the reactive compounds. In this way, the user only has to put the formulation at the desired time under the conditions in which it reacts. The difficulty is to find the appropriate condition or conditions to trigger this reaction, and to be able to control its effects so as to allow a more or less rapid reaction depending on the rate of release in the formulation, of the element. active.

The subject of the present invention is compositions in the form of suspensions or granules, comprising at least one active material. These compositions can, depending on the use of appropriate triggers, release in a controlled manner the active ingredient (s) which they contain.

A first object of the invention therefore consists of a suspension of particles in an aqueous medium, capable of being obtained by implementing the following steps:

(a) a reverse water-in-oil emulsion is prepared from an internal aqueous phase comprising at least one hydrophilic active material, and from an internal organic phase comprising at least one hydrophobic compound having a higher or even melting temperature at 35 ° C, at least one nonionic or cationic surfactant and / or at least one nonionic or cationic amphiphilic polymer; the preparation temperature of the emulsion being greater than or equal to the melting point of the hydrophobic compound; (b) the multiple emulsion is prepared by dispersing the reverse emulsion in an external aqueous phase comprising at least one nonionic polyalkoxylated surfactant and / or at least one nonionic polyalkoxylated amphiphilic polymer and at least one anionic surfactant; the temperature at which the dispersion is carried out being greater than or equal to the melting point of the hydrophobic compound;

(c) the multiple emulsion obtained is brought to a temperature lower than or equal to the melting point of the hydrophobic compound.

A second object of the invention is represented by granules capable of being obtained from the abovementioned suspension, by bringing said suspension into contact, during a step (d), with at least one desiccant.

Finally, it relates to the use of the suspension, of the granules, as an additive in formulations intended for the fields of cosmetics, dental hygiene, food, phytosanitary, exploitation of oil or gas deposits , papermaking, and such formulations. The suspension according to the invention has the advantage of being stable in this sense, in particular, that the liquid active material trapped in the solid organic particles remains substantially localized in said particles. This stability of the system gives the invention many advantages both in terms of the quality of the suspension itself and of the granules which can be prepared from it, and in terms of the preparation of the suspension itself. . Indeed, thanks to this stability, it is not necessary to prepare said suspension in very short times (less than a minute) to avoid any transfer of the hydrophilic active material from the internal aqueous phase to the external aqueous phase. A first consequence of this is that the suspension according to the invention can be prepared by using simple and industrializable means, such as reactors in which the stirring is carried out by means of a frame blade for example. A second consequence is that the cooling step c) can be carried out quite simply by allowing the multiple emulsion to cool. It is therefore not necessary to carry out quenching of the emulsion. Another advantage of the suspension and of the granules according to the invention is that they allow access to compositions encapsulating an aqueous phase comprising a high content of active compound and which has a high ionic strength. It is well known that when it is desired to prepare a multiple emulsion, it is necessary to balance the osmotic pressures of the internal and external aqueous phases to obtain a stable multiple emulsion. However, in the case where the ionic strength is very high, it is almost impossible to balance the osmotic pressures while retaining a manipulable emulsion. In the case of the present invention, the balance of osmotic pressures is no longer necessary. The granules according to the invention have the advantage of being stable on storage. In fact, the granules do not release the active ingredient (s) they contain.

In addition, when the formulation in which they are used is used, the granules according to the invention are able to withstand the conditions of use (relatively high pressure and / or shear) and do not uncontrollably release the active ingredient.

In addition, the granules, depending on the use which is made of the formulation in which they are introduced, make it possible to have controlled release of the active ingredient (s). This phenomenon is possible in particular by controlling the temperature of use of the formulation comprising the granules according to the invention. Thus, a slow diffusion of the active material may be observed if, at the temperature of use of the formulation, the granules are in a solid form. In such a case, the diffusion of said active material will therefore depend on the diffusion coefficient of the latter through the solid organic matrix and then through the walls of the granule. Furthermore, rapid diffusion of the active material may be triggered by bringing the temperature of the formulation to a temperature higher than that of the melting of the hydrophobic compound present in the granule.

However, other objects and advantages will appear more clearly on reading the description and the example which will follow. In the description, the term polymer designates both homopolymers and copolymers.

The first step in the process by which the suspension according to the invention can be obtained consists in preparing a reverse emulsion (water-in-oil) - step (a) -. It should be noted that in the following description, the aqueous phase of this reverse emulsion will be called the internal aqueous phase, and the organic phase, the internal organic phase.

As mentioned previously, the internal aqueous phase comprises at least one hydrophilic active material. It should be noted that said hydrophilic active material can be in a liquid form; in a form dissolved in a water-miscible solvent such as ethanol, propylene glycol, glycerol; as a dispersed solid. It would not be departing from the scope of the present invention to use several active materials, in one or more forms. The total amount of hydrophilic active material is more particularly between 0.1 and 70% by weight of the internal aqueous phase, and preferably between 0.1 and 50% by weight of the internal aqueous phase. Given the large number of fields in which the granules according to the invention can be used, many active materials may be suitable for the implementation of the invention.

By way of example of active materials which can be used, inter alia, in the field of cosmetics, there may be mentioned in particular α-hydroxy acids, such as citric, lactic, glycolic and salicylic acids in particular; hydrophilic vitamins such as vitamin C and its derivatives; biocides, as well as hydrating agents, such as, for example, glycerin, urea, hyaluronic acid, allantoin, aloe, plant extracts from terrestrial and marine plants. In the food sector, mention may be made, for example, of crosslinking agents of texturing polymers, such as alginates, carrageenans, among others, chosen from divalent calcium salts.

In the phytosanitary field, hydrophilic pesticides or hydrophilic nutrients can be used which promote plant growth and development. As regards the field of exploitation or construction of oil or gas wells, the present invention can be implemented for hydrophilic active materials which can be used in particular during cementing, completion, drilling and stimulation of wells (eg fracturing). As examples of active materials which can be used in this field, mention may be made of crosslinking catalysts for cement compositions, such as for example lithium salts, such as chloride, acetate. Mention may likewise be made of compounds capable, inter alia, of degrading polysaccharides, such as for example carboxylic acids (in particular citric acid), enzymes (in particular cellulases), oxidants. In the field of silicones, mention may be made of crosslinking agents such as, for example, calcium salts, potassium hydroxide.

As active ingredients suitable in the field of papermaking, mention may in particular be made of calcium chloride and hydrochloric acid.

As regards the internal organic phase, this comprises at least one hydrophobic compound having a melting point greater than or equal to 35 ° C. Preferably the melting temperature is less than or equal to 100 ° C.

It should be noted that this hydrophobic compound represents the internal organic phase.

More particularly, said hydrophobic compound is chosen from compounds having a solubility in water of less than 10% by weight, more particularly less than 5% by weight, preferably less than 1% by weight, whatever the form in which said compound is found (in solid form or in the molten state).

According to a preferred embodiment of the invention, said hydrophobic compound is chosen from: + animal or vegetable waxes or fats, mineral waxes. By way of examples, mention may be made of waxes of animal origin such as beeswax, waxes of vegetable origin such as carnauba wax and cocoa butter. We can similarly use animal fats such as pork, sheep, for example. As mineral wax, there may be mentioned by way of illustration, paraffinic waxes;

+ C14-C40 mono- or polycarboxylic acids, saturated or unsaturated, optionally comprising one or more hydroxyl groups; mono- or polyesters of C14-C40 mono- or polycarboxylic acids, optionally comprising one or more hydroxyl groups; mono- or polyalcohols, saturated or unsaturated, comprising 14 to 40 carbon atoms. It should be noted that the alcohols from which the esters are derived can comprise 1 to 40 carbon atoms, and include one or more hydroxyl functions, whether or not esterified. By way of example of this type of compound, mention may be made, for example, of palmitic, stearic and behenic acids, the alcohols corresponding to these acids, as well as the esters of such acids, such as mono-, di- or tri- glycerides.

+ synthetic resins or gums such as silicone gums or resins, alkyd resins, epoxy resins; tackifying resins.

The internal organic phase can consist of one or more hydrophobic compounds. The internal organic phase may optionally comprise at least one hydrophobic active material, as soon as it is compatible with the hydrophilic active material present in the internal aqueous phase.

The hydrophobic active material is more particularly chosen from compounds whose solubility in water does not exceed 10% by weight at 25 ° C. It can be either in liquid form, dissolved in an organic solvent miscible with the internal organic phase, or even in the form of a dispersed solid. However, it is more advantageous to use an active material which is not dissolved in a solvent. In addition, it is preferable to choose it from the compounds which are solid at room temperature, and advantageously from those having a melting point greater than or equal to 35 ° C.

If the internal organic phase comprises one or more hydrophobic active materials, their content generally does not represent more than 50% by weight of said internal organic phase.

In the case where the active material is liquid at ambient temperature or has a melting temperature below 30 ° C., the content of active material preferably does not represent more than 10% by weight of the internal organic phase.

Finally, it should be noted that it is not impossible that the organic phase itself is considered as a hydrophobic active material. The internal organic phase also comprises at least one nonionic or cationic surfactant and / or at least nonionic or cationic amphiphilic polymer.

More particularly, the nonionic surfactant and / or the nonionic amphiphilic polymer present in the internal organic phase are chosen from those which verify the conditions of the Bancroft rule (2 ^nd World Congress of Emulsions, 1997,

Bordeaux, France). More particularly, they are chosen from those which satisfy both of the two conditions below: when they are mixed with the internal organic phase, at a concentration of between 0.1 and 15% by weight of said phase at 25 ° C, are in the form of a solution in all or part of the indicated concentration range.

- when mixed with the internal aqueous phase, at a concentration between 0.1 and 15% by weight of said phase and at 25 ° C, are in the form of a dispersion in all or part of the range of indicated concentration. Preferably, the nonionic surfactant has an HLB (hydrophilic / lipophilic balance) value less than or equal to 8.

As examples of surfactants capable of entering into the composition of the reverse emulsion, mention may be made of surfactants, alone or as a mixture, chosen from:

- alkoxylated fatty alcohols - alkoxylated triglycerides

- alkoxylated fatty acids

- optionally alkoxylated sorbitan esters

- alkoxylated fatty amines

- the alkoxylated di (phenyl-1 ethyl) phenols - the alkoxylated tri (phenyl-1 ethyl) phenols

- Alkoxylated phenol alkyls the number of alkoxylated units (oxyethylenated, oxypropylenated, oxybutylenated) is such that the value of HLB is less than or equal to 8.

The alkoxylated fatty alcohols generally contain from 6 to 22 carbon atoms, the alkoxylated units being excluded from these numbers.

The alkoxylated triglycerides can be triglycerides of plant or animal origin.

The optionally alkoxylated sorbitan esters are cyclized sorbitol fatty acid esters comprising from 10 to 20 carbon atoms such as lauric acid, stearic acid or oleic acid.

Alkoxylated fatty amines generally have from 10 to 22 carbon atoms, the OE and OP units being excluded from these numbers. Alkoxylated alkylphenols generally have one or two alkyl groups, linear or branched, having 4 to 12 carbon atoms. By way of example, mention may in particular be made of octyl, nonyl or dodecyl groups.

As for the amphiphilic polymer, this advantageously comprises at least two blocks, and more particularly at least one hydrophobic block and at least one neutral hydrophilic block.

In the case where the amphiphilic polymer comprises at least three blocks, and more particularly three blocks, the polymer is preferably linear. In addition, the hydrophobic blocks are more particularly at the ends. If the polymers comprise more than three blocks, the latter are preferably in the form of grafted or combed polymers.

In what follows, even if this constitutes an abuse of language, the term amphiphilic block polymer will be used interchangeably for linear block polymers and grafted or combed polymers. Said amphiphilic polymers can advantageously be obtained by so-called living or controlled radical polymerization. By way of nonlimiting examples of so-called living or controlled polymerization processes, reference may in particular be made to applications WO 98/58974 (xanthate), WO 98/01478 (dithioesters), WO 99/03894 (nitroxides); WO 99/31144 (dithiocarbamates). Amphiphilic polymers can also be obtained by anionic polymerization.

They can likewise be prepared by bringing into play polymerizations by ring opening (in particular anionic or cationic), or by chemical modification of the polymer. The grafted or combed polymers can also be obtained by methods known as direct grafting and copolymerization.

Direct grafting consists in polymerizing the monomer (s) chosen by radical, in the presence of the selected polymer to form the backbone of the final product. If the monomer / skeleton couple as well as the operating conditions are judiciously chosen, then there may be a transfer reaction between the growing macroradical and the skeleton. This reaction generates a radical on the skeleton and it is from this radical that the graft grows. The primary radical originating from the initiator can also contribute to the transfer reactions.

As regards the copolymerization, it firstly implements the grafting at the end of the future pendant segment, of a function which can be polymerized by the radical route. This grafting can be carried out by usual methods of organic chemistry. Then, in a second step, the macromonomer thus obtained is polymerized with the monomer chosen to form the skeleton and a so-called "comb" polymer is obtained. Among the hydrophobic monomers from which the hydrophobic block (s) of the amphiphilic polymer can be prepared, there may be mentioned in particular: esters of mono- or polycarboxylic acids, linear, branched, cyclic or aromatic, comprising at least one ethylenic unsaturation, preferably comprising 8 to 30 carbon atoms, optionally carrying a hydroxyl group; αβ-ethylenically unsaturated nitriles, vinyl ethers, vinyl esters, vinyl aromatic monomers, vinyl or vinylidene halides, linear or branched hydrocarbon monomers, aromatic or not, comprising at least one ethylenic unsaturation, type monomers cyclic siloxane or not, chlorosilanes; propylene oxide, butylene oxide; alone or in mixtures, as well as the macromonomers derived from such monomers.

As specific examples of hydrophobic monomers capable of entering into the preparation of the hydrophobic block or blocks of the amphiphilic block polymer, there may be mentioned: (meth) acrylic acid esters with an alcohol comprising 1 to 12 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) isobutyl acrylate, 2-ethylhexylacrylate; vinyl acetate, vinyl Versatate®, vinyl propionate, vinyl chloride, vinylidene chloride, methyl vinyl ether, ethyl vinyl ether; vinyl nitriles more particularly include those having 3 to 12 carbon atoms, such as in particular acrylonitrile and methacrylonitrile; - styrene, α-methylstyrene, vinyltoluene, butadiene, isoprene, chloroprene; alone or in mixtures, as well as the macromonomers derived from such monomers.

The preferred monomers are the esters of acrylic acid with linear or branched C- alcohols | -C4 such as methyl, ethyl, propyl and butyl acrylate, vinyl esters such as vinyl acetate, styrene, α-methylstyrene.

As regards the nonionic hydrophilic monomers from which the amphiphilic block polymers can be obtained, there may be mentioned, without intending to be limited thereto, ethylene oxide, the amides of mono- or polycarboxylic acids , linear, branched, cyclic or aromatic, comprising at least one ethylenic unsaturation or derivatives, such as (meth) acrylamide, N-methyloI (meth) acrylamide; hydrophilic esters derived from (meth) acrylic acid such as for example 2-hydroxyethyl (meth) acrylate; vinyl esters making it possible to obtain polyvinyl alcohol blocks after hydrolysis, such as vinyl acetate, Versatate® vinyl, vinyl propionate, alone, in combination, as well as the macromonomers derived from such monomers. It is recalled that the term macromonomer designates a macromolecule carrying one or more polymerizable functions. However, the preferred hydrophilic monomers are acrylamide and methacrylamide, alone or as a mixture, or in the form of macromonomers.

Preferably, the amphiphilic block polymers have a molar mass by weight less than or equal to 100,000 g / mol, more particularly between 1,000 and 50,000 g / mol, preferably between 1,000 and 20,000 g / mol. It is specified that the molar masses by weight indicated above are theoretical molar masses, evaluated as a function of the respective amounts of the monomers introduced during the preparation of said polymers.

By way of example of an amphiphilic block polymer suitable for implementing the invention, mention may be made of polyhydroxystearate - polyethylene glycol - polyhydroxystearate triblock polymers (the products of the Arlacel range from ICI are an example), polymers with polyalkyl polyether grafted polydimethylsiloxane blocks

(like Tegopren brand products marketed by Goldschmidt).

Among the cationic amphiphilic surfactants and polymers, it is possible in particular to use aliphatic or aromatic fatty amines, quaternary ammonium derivatives (Glokill PQ, Rhodaquat RP50, sold by Rhodia Chimie), cationic polymers of hydrophobic modified polyquaternium type.

It is also possible to use cationic derivatives of polysaccharides, such as guar or cellulose derivatives.

It is likewise possible to use cationic polymers functionalized by hydrophobic groups such as C1-C14, preferably C2-C8 alkyl chains, optionally having a hydroxyl group. These hydrophobic groups are attached to the main polymer chain via ether bonds.

Furthermore, and in the case of cationic guars modified hydrophobic or not, the cationic group is a quaternary ammonium group carrying three radicals, identical or not, chosen from hydrogen, an alkyl radical comprising 1 to

22 carbon atoms, more particularly 1 to 14, advantageously 1 to 3 carbon atoms. The counter ion is a halogen, preferably chlorine.

In the case of cationic celluloses modified hydrophobic or not, the cationic group is a quaternary ammonium group carrying three radicals, identical or not, chosen from hydrogen, an alkyl radical comprising 1 to

10 carbon atoms, more particularly 1 to 6, advantageously 1 to 3 carbon atoms. The counter ion is a halogen, preferably chlorine. According to a preferred embodiment of the invention, at least one nonionic amphiphilic polymer is used.

An advantageous variant of this embodiment consists in associating with said polymer, during step (a), at least one nonionic surfactant. The total amount of nonionic or cationic surfactant and / or nonionic or cationic amphiphilic polymer more particularly represents 0.1 to 15% by weight of the internal aqueous phase, preferably 2 to 10% by weight of the aqueous phase internal.

In accordance with a particularly advantageous embodiment of the present invention, the internal aqueous phase may comprise at least one additive chosen from salts such as the halides of alkali or alkaline earth metals (such as sodium chloride, calcium chloride) , or alkali or alkaline earth metal sulfates (such as magnesium sulfate), or mixtures thereof. The internal aqueous phase may also comprise at least one additive chosen from sugars, such as glucose for example, or also from polysaccharides, such as dextran in particular, or mixtures thereof.

The salt concentration in the internal aqueous phase, when the latter is present, is more particularly between 0.05 and 1 mol / l, preferably 0.1 to 0.4 mol / l. The sugar and / or polysaccharide concentration is such that the osmotic pressure of the internal aqueous phase comprising the sugar and / or polysaccharide corresponds to the osmotic pressure of an internal aqueous phase comprising 0.05 to 1 mol / l of salt.

In addition, the inverse emulsion of the multiple emulsion more particularly has a weight proportion internal aqueous phase / internal organic phase, between 10/90 and 90/10. Preferably, the weight proportion of internal aqueous phase / internal organic phase is between 30/70 and 80/20.

The reverse emulsion is prepared using conventional methods. Thus, to cite only one example, a first mixture is prepared, comprising water, the hydrophilic active material, where appropriate, the surfactant and / or the cationic polymer, and optionally the additive, and on the other hand, a second mixture comprising the hydrophobic compound and optionally the surfactant and / or the amphiphilic polymer. The first mixture is then added to the second, with stirring.

Usually, agitation is determined in difficulty by a person skilled in the art and depends in particular on the viscosity of the mixture to be homogenized. Particularly advantageously, the homogenization is done by means of a frame blade. However, it should be noted that other means of agitation involving stronger pressures are not excluded, even if it is not necessary to use them. The preparation of the reverse emulsion is carried out at a temperature greater than or equal to the melting point of the hydrophobic compound. Thus, the temperature for preparing the emulsion takes place at a temperature greater than or equal to 35 ° C. Furthermore, the temperature at which the reverse emulsion is prepared is more particularly less than or equal to 100 ° C.

The duration of the agitation can be determined without difficulty by a person skilled in the art and depends on the type of apparatus used. It is preferably sufficient to obtain an inverse emulsion whose average droplet size is between 0.1 and 10 μm, preferably between 0.1 and 5 μm (measured by means of a Horiba granulometer). It is recalled that the average size of the droplets corresponds to the median diameter in volume (dso) which represents the diameter of the particle equal to 50% of the cumulative distribution.

The second step of the process by which the suspension according to the invention can be obtained, consists in preparing the multiple emulsion by dispersing the reverse emulsion which has just been described in an external aqueous phase (step (b)) . Said external aqueous phase will now be described. It should be noted that preferably, the composition of the internal aqueous phase is different from that of the external aqueous phase.

The external aqueous phase comprises at least one nonionic polyalkoxylated surfactant and / or at least one nonionic polyalkoxylated amphiphilic polymer, and at least one anionic surfactant.

As regards the nonionic polyalkoxylated surfactant or the nonionic polyalkoxylated amphiphilic polymer, as well as the anionic surfactant, the latter are chosen from those which satisfy both of the two conditions below: - when they are mixed with the phase external aqueous, at a concentration between 0.1 and 10% by weight of said phase at 25 ° C, are in the form of a solution in all or part of the concentration range indicated. - when mixed with the internal organic phase, at a concentration between 0.1 and 10% by weight of said phase and at 25 ° C, are in the form of a dispersion in all or part of the range of indicated concentration. Preferably, the nonionic polyalkoxylated surfactant present in the external aqueous phase has an HLB value greater than or equal to 10.

By way of example of a nonionic polyalkoxylated surfactant, suitable for implementing the invention, the following surfactants may be mentioned, among others, alone or in mixtures:

- alkoxylated fatty alcohols

- alkoxylated triglycerides - alkoxylated fatty acids

- alkoxylated sorbitan esters

- alkoxylated fatty amines

- alkoxylated alkyl phenols.

The alkoxylated units are preferably oxyethylenated units or a mixture of oxyethylenated and oxypropylenated units.

The surfactants mentioned as suitable for the preparation of the reverse emulsion can be used, with the exception that the number of oxyethylenated and oxypropylenated units, if they are present, must be adapted as a function of the desired HLB value. For purely illustrative purposes, the number of oxyethylenated and optionally oxypropylenated units is between 10 and 100.

As regards the nonionic amphiphilic polymer, a polymer comprising at least two blocks is used, one of them being hydrophilic, the other hydrophobic.

What has been indicated above in the context of the description of the nonionic hydrophilic monomers and of the hydrophobic monomers which can be used for the preparation of amphiphilic block polymers entering into the composition of the reverse emulsion, remains valid and will not be repeated here. The proportion and the nature of said monomers being such that the resulting polymer satisfies the conditions set out previously (Bancroft rule - two conditions).

According to a particular embodiment, the polymer is obtained from hydrophilic monomers chosen from acrylamide and methacrylamide, alone or as a mixture, or in the form of macromonomers; preferred hydrophobic monomers are esters of acrylic acid with linear or branched C- alcohols _| - C4 such as methyl, ethyl, propyl and butyl acrylate, vinyl esters such as vinyl acetate, styrene, α-methylstyrene.

In the case where said polymer comprises at least three blocks, and more particularly three blocks, the polymer is advantageously linear. In addition, the hydrophilic blocks are more particularly at the ends.

If the polymers comprise more than three blocks, the latter are preferably in the form of grafted or combed polymers.

According to another advantageous embodiment, the amphiphilic polymer comprises polyalkoxylated blocks, and preferably only comprises polyalkoxylated blocks, of which at least one is hydrophobic, the other hydrophilic.

For purely indicative purposes, these polymers are obtained by bringing into play ring-opening polymerizations, in particular anionic. More particularly, said nonionic polyalkoxylated amphiphilic polymers are chosen from polymers whose molar mass by weight is less than or equal to 100,000 g / mol (measured by GPC, polyethylene glycol standard), preferably between 1,000 and 50,000 g / mol, preferably between 1000 and 20000 g / mol. Examples of polymers of this type that may be mentioned, inter alia, are polyethylene glycol / polypropylene glycol / polyethylene glycol triblock polymers. Such polymers are well known and are in particular marketed under the brands Pluronic (marketed by BASF), Arlatone (marketed by ICI).

Note that it would not be departing from the scope of the present invention to combine one or more surfactants with one or more amphiphilic polymers.

However, according to a preferred embodiment of the invention, the external aqueous phase comprises one or more amphiphilic polymers.

The content of nonionic polyalkoxylated surfactant and / or nonionic polyalkoxylated amphiphilic polymer present in the external aqueous phase is more particularly between 0.1 and 10% by weight relative to the weight of the inverse emulsion. Preferably, the content of nonionic surfactant and / or of amphiphilic polymer is between 1 and 5% by weight relative to the weight of the reverse emulsion.

In addition, the proportion by weight of inverse emulsion relative to the external aqueous phase is usually between 30/70 and 90/10, preferably between 50/50 and 90/10.

The anionic surfactant represents one of the essential constituent elements of the external aqueous phase.

With regard to this surfactant, the following surfactants may be cited by way of illustration only:

- the alkyl esters sulfonates, for example of formula R-CH (SO ₃ M) -CH ₂ COOR ', where R represents a C ₈ -C ₂ o, preferably C ₁₀ -C ₁₆ hydrocarbon radical, optionally carrying one or more unsaturations, R ′ an alkyl radical in CC ₆ , preferably in CC ₃ and M a hydrogen atom or an alkaline cation (sodium, potassium, lithium), substituted or unsubstituted ammonium (methyl-, dimethyl-, trimethyl-, tetramethylammonium, dimethylpiperidinium ...) or derived from an alkanolamine (monoethanolamine, diethanolamine, triethanolamine ...). Mention may very particularly be made of methyl ester sulfonates whose radical R is C ₁₄ -C ₁₆ ; C ₉ -C ₂ alkylbenzenesulfonates, primary or secondary C ₈ -C ₂₂ alkylsulfonates, alkylglycerol sulfonates, sulfonated polycarboxylic acids described in GB-A-1 082 179, paraffin sulfonates;

the alkylestersulphates, for example of formula R-CH (OSO ₃ M) -CH ₂ COOR ', where R represents a C ₈ -C ₂ o, preferably C ₁₀ -C ₁₆ , hydrocarbon radical, optionally carrying one or more unsaturations, R ′ an alkyl radical in CC ₆ , preferably in C _r C ₃ and M has the same definition as above;

- The alkyl sulphates, for example of formula ROSO ₃ M, where R represents a C ₁₀ -C ₂ , preferably C ₁₂ -C ₂₀ , alkyl or hydroxyalkyl radical; M has the same definition as above; such as, for example, sodium dodecyl sulfate;

- The alkyl ether sulfates, for example of formula RO (AO) _n SO ₃ M where R represents a C ₁₀ -C ₂₄ , preferably C ₁₂ -C ₂₀ , alkyl or hydroxyalkyl radical; AO representing an ethoxylated, propoxylated group, or combinations thereof; M has the same definition as above; n generally varying from 1 to 4, for example laurylethersulfate with n = 2.

the sulphated alkylamides, for example of the formula RCONHR'OSO ₃ M where R represents an alkyl radical in C ^ C ^, preferably in C ₆ -C ₂₀ , R 'an alkyl radical in C ₂ -C ₃ , M a la same definition as above, as well as their polyalkoxylated derivatives (ethoxylated (OE), propoxylated (OP), or their combinations); the salts of saturated or unsaturated fatty acids, for example such as those in C _β -C ₂₄ , preferably in C ₁₄ -C ₂₀ , N-acyl N-alkyltaurates, alkylisethionates, alkylsuccinamates and alkylsulfosuccinates, monoesters or sulfosuccinate diesters, N-acyl sarcosinates, polyethoxycarboxylates; and

- the phosphate esters of alkyl and / or of alkyl ether and / or of alkylarylether. The amount of anionic surfactant preferably represents 0.1 to 10% by weight of the content of polyalkoxylated nonionic surfactant and / or nonionic polyalkoxylated amphiphilic polymer.

Furthermore, according to an advantageous embodiment of the present invention, the multiple emulsion comprises at least one polysaccharide or a mixture of polysaccharides.

By way of nonlimiting example of polysaccharides, mention may be made of dextran, starch, maltodextrin, xanthan gum, galactomannans such as guar or locust bean.

The polysaccharide content, if present, represents 0.1 to 2% of the external aqueous phase, preferably 0.5 to 1.5% by weight of the external aqueous phase.

In addition, the external aqueous phase can comprise at least one preservative.

Preferably, and essentially for reasons of simplification of the preparation of the multiple emulsion, the preservative is chosen from compounds which are soluble at least partially in the external aqueous phase.

By way of example of preservatives capable of entering into the composition of the external aqueous phase, there may be mentioned, among others, the following compounds: Germaben (Sutton Lab), propylene glycol, diazolidinyl urea, methyl-, ethyl-, propyl- and butyl-paraben; Phenonip (Nipa) Phenoxyethanol; Glydant (Lonza) DMDM hydantoin.

If present, the preservative content generally represents 0.1 to 2% by weight of the external aqueous phase. According to a variant of the present invention, the external aqueous phase can comprise a dispersed solid.

All the solids used in the various applications mentioned may be suitable. Preferably, the size of this dispersed solid is close to or smaller than that of the droplets of the reverse emulsion. If the dispersed solid is present, its content represents more particularly 1 to 50% by weight of the external aqueous phase, preferably 5 to 25% by weight.

It should be noted that in the case of the multiple emulsion according to the invention, and unlike conventional multiple emulsions, it is not necessary to introduce into the external aqueous phase a compound which makes it possible to balance the osmotic pressures of the internal and external aqueous phases. This represents a definite advantage in the case where the ionic strength of the internal aqueous phase, provided for example by a large content of hydrophilic active material in this phase, is so high that it is almost impossible to be able to adjust the osmotic pressures and always keep a manipulable composition.

The preparation of the multiple emulsion can be carried out according to any known method.

As an example, we can proceed as follows. Firstly, the external aqueous phase is prepared by mixing the polyalkoxylated nonionic surfactant and / or the polyalkoxylated nonionic amphiphilic polymer, the anionic surfactant, optionally the polysaccharide, and water.

The external aqueous phase can optionally be left to stand for 1 to 12 hours at room temperature.

Next, the actual multiple emulsion is prepared by adding the reverse emulsion to the external aqueous phase.

In accordance with a first possible embodiment, the multiple emulsion is obtained with stirring, by adding the reverse emulsion slowly at the start.

Agitation can be done by means of a paddle frame. Typically, the stirring speed is usually relatively slow, on the order of 400 rpm.

The preparation of the multiple emulsion is carried out at a temperature greater than or equal to the melting point of the hydrophobic compound of the internal organic phase. Thus, the temperature of preparation of the emulsion takes place at a temperature greater than or equal to 35 ° C. Furthermore, the temperature at which the emulsion is prepared is more particularly less than or equal to 100 ° C.

A second method of preparing the multiple emulsion consists in introducing the external aqueous phase into the reverse emulsion, without stirring. Then, after having introduced all of the external aqueous phase into the reverse emulsion, the whole is stirred.

Advantageously, the stirring is carried out by means of moderately shearing mixers, as are for example the agitators provided with paddle-frame, the planetary type mixers, or those having a scraping mobile and a paddle rotating in opposite directions. (cons-stirring).

This stirring operation takes place at a temperature above the melting temperature of the compound constituting the internal organic phase.

At the end of this stirring step, a concentrated multiple emulsion is obtained whose inverse emulsion / external aqueous phase weight ratio is between 50/50 and 90/10, and preferably between 70/30 and 90/10.

Depending on the applications, an optional additional dilution step can be considered.

It is carried out by adding, with stirring, an aqueous dilution phase comprising at least one surfactant and / or at least one polymer present in the external aqueous phase, and which preferably are the same as those present in the external phase of the concentrated multiple emulsion.

Preferably, the quantity of external surfactant and / or amphiphilic polymer in the aqueous dilution phase is such that the quantity of external surfactant and / or amphiphilic polymer is included in the ranges indicated above (the proportions being expressed relative to the '' aqueous dilution phase and external aqueous phase of the concentrated multiple emulsion).

It should be noted that the amount of dilution water is advantageously such that the weight ratio reverse emulsion / external aqueous phase of the diluted multiple emulsion is included in the ranges mentioned above. This process was notably the subject of a French patent application

FR 01 15982 filed on December 11, 2001.

The average droplet size (dso) of the multiple emulsion advantageously varies between 0.1 and 100 μm, more particularly between 1 and 50 μm, preferably between 5 and 30 μm (measured using a Horiba granulometer). Step (c) consists in bringing the multiple emulsion thus obtained to a temperature below the melting temperature of the hydrophobic compound. Advantageously, the temperature of the multiple emulsion at the end of this step is room temperature. It should be noted that the cooling can be done in a controlled manner or by letting the emulsion cool.

At the end of this stage, the multiple emulsion with the appearance of a paste.

The average particle size of the suspension (dso) is preferably between 0.1 and 100 μm, more particularly between 1 and 50 μm, preferably between 5 and 30 μm (measured using a Horiba granulometer). It should be noted that the average size of the droplets of the multiple emulsion and that of the particles of the suspension are similar. More specifically, this cooling step does not have the effect of substantially coalescing the particles together. In the case where the external aqueous phase comprises a dispersed solid, obtaining the multiple emulsion can be carried out as indicated above, then adding to the multiple emulsion obtained, concentrated or diluted, said solid dispersed in an aqueous phase having preferably the same composition as the external phase of the multiple emulsion. It is further understood that the amount of external aqueous phase provided with the multiple emulsion and the dispersed solid is such that the concentration ranges indicated above are verified.

As indicated above, another object of the invention consists of granules which can be obtained from the suspension which has just been described.

Thus, the suspension is brought into contact, during a step d), with at least one desiccant.

The term “desiccant” denotes any porous compound capable of absorbing large quantities of water.

Among the desiccants which may be used, there may be mentioned without intending to be limited thereto, silica, clays such as bentonite, montmorillonite, kaolin, calcium carbonate, calcium phosphate, alone or in mixture.

The amount of desiccant is determined according to various criteria including the desired appearance of the multiple emulsion after contacting with the desiccant, conditions for a possible additional drying step. As an illustration, the content of desiccant added more particularly represents 5 to 40% by weight of the multiple emulsion.

The contact of the multiple emulsion and the desiccant is carried out in a conventional manner, with stirring.

The objective followed during this stage is to remove most of the water from the external aqueous phase. It should be noted that this drying step has the result of conserving almost completely (purely by way of illustration, more than about 90%) the water coming from the internal aqueous phase. At the end of this step, the granules obtained advantageously have an average particle size of between 100 μm and 5 mm.

According to a particular and preferred variant of the invention, an additional drying step is implemented, once step (c) has been carried out, at a temperature below the melting temperature of the hydrophobic compound present in the internal organic phase.

This additional drying operation is usually carried out under a sweep of air or any other inert gas (nitrogen, etc.)

This drying can be carried out by any means known to those skilled in the art. Advantageously, said drying is carried out in an oven, or by means of a fluidized bed.

The objective of this additional drying step is to continue the drying implemented by means of the desiccant, while still conserving, almost completely, the water coming from the internal aqueous phase. It should be noted that the average size of the granules obtained at the end of this additional drying step and that of the granules obtained at the end of the drying by the desiccant are similar, or even practically identical. Thus, the average size is between 100 μm and 5 mm.

At the end of the process, granules are obtained, which can, if necessary, be the subject of a subsequent implementation, such as an agglomeration step.

As indicated above, the suspension, as well as the granules according to the invention can enter into the composition of formulations intended to be used in many fields, such as those of cosmetics, dental hygiene, 'food, phytosanitary, exploitation of oil or gas deposits, papermaking.

As examples of compositions in which the suspension and / or the granules according to the invention can be used as an additive, mention may be made of the formulations for the skin, the hair, the eyelashes and / or the nails, the conditioners, formulations for styling or for facilitating combing of the hair, hand and body lotions, products regulating the hydration of the skin, toilet milks, make-up removing compositions, depilatory products, creams or lotions for protection against the sun and ultraviolet radiation, care creams, anti-acne preparations, make-up formulations such as mascaras, foundations, blush, nail polish, products intended to be applied to the lips, etc. . The toothpastes can likewise comprise the suspension and / or the granules according to the invention.

The latter can also be used in the composition of formulations for cementing oil or gas wells. Note that the suspension and the granules according to the invention are particularly suitable if it is desired to have a rapid release of the hydrophilic active material, triggered by a temperature greater than or equal to the melting point of the hydrophobic compound of the internal organic phase. . These types of conditions are found in particular when using cementing compositions for oil or gas wells.

The suspension and the granules according to the invention are likewise very advantageous in that they allow a slow release of the active material under certain conditions, when the temperature of use of the formulation in which they are introduced is lower than the melting temperature of the hydrophobic compound of the internal organic phase.

A concrete but nonlimiting example of the invention will now be presented.

EXAMPLE

1 / Reverse emulsion

Composition of the reverse emulsion: * 60% aqueous phase comprising a lithium chloride solution at 450 g / l;

* 40% of oil phase (beeswax and surfactant) comprising 5% of Arlacel P135 surfactant (ICI - Uniquema (*);% expressed by weight relative to the weight of aqueous phase) and 5% by weight of Alkamuls S80 (Rhodia Chimie (**);% expressed by weight relative to the weight of aqueous phase).

(*) Arlacel P 135: Polyhydroxystearate - PEG - Polyhydroxystearate; HLB = 5-6;

Mw≈ 5000 g / mol).

(**) Alkamuls S80: sorbitan monooleate.

Preparation of the reverse emulsion

100 g of reverse emulsion are prepared.

3 g of Arlacel P135, 3 g of Alkamuls S80 and 34 g of beeswax pellets are introduced into a metal beaker, then the whole is heated to 75 ° C. The molten mixture is then homogenized with Ultra-turrax at 9500 rpm. In a beaker, 60 g of lithium chloride solution at 450 g / l are weighed and this solution is heated to around 70 ° C.

The lithium chloride solution is added dropwise to the molten organic phase obtained above, with stirring (Ultra-turrax; 9500 rpm). Once the addition is complete, stirring is continued for another 2 minutes.

2 / Multiple emulsion

Composition of the multiple emulsion:

* 50% reverse emulsion (comprising 2% lithium chloride; expressed relative to the total weight of the emulsion)

* 50% of external aqueous phase containing:

- 2% of Arlatone F127G (*) (HERE - Uniquema;% by weight expressed relative to the weight of the inverse emulsion);

- 5% sodium dodecyl sulfate (% by weight expressed relative to the weight of Arlatone F127G);

- 1% of Rhodopol 23 (**) (Rhodia Chimie;% by weight expressed relative to the weight of the inverse emulsion).

(*) Arlatone F127G: HO (CH ₂ CH2θ) _x (OCH (CH3) CH2θ) y (CH2CH ₂ O) _z H with verification of the following inequality: 82 <x + z <90 and the polymer comprises 7 OP units for 1 mole of product). (**) Rhodopol 23: xanthan gum.

Preparation of multiple emulsion

Preparation of the external aqueous phase:

100 g of external aqueous phase are prepared.

50 g of solution of Arlatone F 127G and sodium dodecyl sulfate are weighed. 50 g of 2% Rhodopol 23 solution in water are weighed.

The whole is mixed in the pale frame at 200 revolutions / minute, at a temperature between 70 and 75 ° C.

Preparation of the multiple emulsion: The 100 g of the reverse emulsion obtained in point 1 / are introduced, with stirring with a frame paddle at 600 rpm, drop by drop, into the external aqueous phase, at a temperature between 70 and 75 ° C. 3 / Drying of the multiple emulsion

A quantity of multiple emulsion is weighed to which 30% by weight of silica is added (Zeosil 1165 MP; sold by Rhodia Chimie) relative to the weight of multiple emulsion.

A composition is obtained having the appearance of a shortbread dough.

The paste thus obtained is then placed in an oven at 40 ° C for 12 hours.

The resulting granules are stable on storage.

Claims

1. Suspension of particles in an aqueous medium, characterized in that it is capable of being obtained by implementing the following steps:

(a) a reverse water-in-oil emulsion is prepared from an internal aqueous phase comprising at least one hydrophilic active material, and from an internal organic phase comprising at least one hydrophobic compound having a higher or equal melting temperature at 35 ° C, at least one nonionic or cationic surfactant and / or at least nonionic or cationic amphiphilic polymer; the preparation temperature of the emulsion being greater than or equal to the melting point of the hydrophobic compound;

(b) the multiple emulsion is prepared by dispersing the reverse emulsion in an external aqueous phase comprising at least one nonionic polyalkoxylated surfactant and / or at least one nonionic polyalkoxylated amphiphilic polymer and at least one anionic surfactant; the temperature at which the dispersion is carried out being greater than or equal to the melting point of the hydrophobic compound;

2. Suspension according to the preceding claim, characterized in that the average size of the particles of the suspension is between 0.1 and 100 μm, more particularly between 1 and 50 μm, preferably between 5 and 30 μm.

3. Suspension according to one of the preceding claims, characterized in that the hydrophilic active material is chosen from the following:

+ field of cosmetics: α-hydroxy acids; hydrophilic vitamins; biocides, moisturizers.

+ food sector: crosslinking agents of texturing polymers, as divalent calcium salts.

+ phytosanitary field: hydrophilic pesticides, hydrophilic nutrients promoting plant growth and development.

+ field of exploitation or construction of oil or gas wells: hydrophilic active materials usable during cementing, completion, drilling and stimulation of wells, such as catalysts for crosslinking cement compositions; compounds liable to degrade polysaccharides, such as carboxylic acids, enzymes, oxidants.

+ area of silicones: crosslinking agents such as calcium salts. + area of papermaking: calcium chloride, hydrochloric acid.

4. Suspension according to one of the preceding claims, characterized in that the total amount of hydrophilic active material is between 0.1 and 70% by weight of the internal aqueous phase, preferably between 0.1 and 50% by weight of the internal aqueous phase.

5. Suspension according to one of the preceding claims, characterized in that the hydrophobic compound has a melting point less than or equal to

100 ° C.

6. Suspension according to one of the preceding claims, characterized in that the hydrophobic compound is chosen from: + waxes or fats of animal or vegetable origin, mineral waxes;

+ C14-C40 mono- or polycarboxylic acids, saturated or unsaturated, optionally comprising one or more hydroxyl groups; mono- or polyesters of C14-C40 mono- or polycarboxylic acids, optionally comprising one or more hydroxyl groups; mono- or polyalcohols, saturated or unsaturated, comprising 14 to 40 carbon atoms;

7. Suspension according to one of the preceding claims, characterized in that the nonionic surfactant and / or the nonionic amphiphilic polymer present (s) in the internal organic phase is chosen from those which satisfy both of the two conditions below. below: - when they are mixed with the internal organic phase, at a concentration of between 0.1 and 15% by weight of the said phase at 25 ° C., are in the form of a solution in all or part of the indicated concentration range, when mixed with the internal aqueous phase, at a concentration of between 0.1 and 15% by weight of said phase and at 25 ° C., are in the form of a dispersion in all or part of the indicated concentration range.

8. Suspension according to one of the preceding claims, characterized in that one implements in step (a) at least one nonionic amphiphilic polymer associated with at least one nonionic surfactant.

9. Suspension according to one of the preceding claims, characterized in that the amount of nonionic or cationic surfactant and / or nonionic or cationic amphiphilic polymer represents 0.1 to 10% by weight of the internal aqueous phase, preferably from 2 to 10% by weight of the internal aqueous phase.

10. Suspension according to one of the preceding claims, characterized in that the multiple emulsion has a weight proportion aqueous phase / organic phase of between 10/90 and 90/10, preferably between 30/70 and 80/20 .

11. Suspension according to one of the preceding claims, characterized in that the nonionic polyalkoxylated surfactant and / or the nonionic polyalkoxylated amphiphilic polymer, as well as the anionic surfactant, present in the external aqueous phase are chosen from those which verify both of the two conditions below: - when mixed with the external aqueous phase, at a concentration of between 0.1 and 10% by weight of said phase at 25 ° C., are in the form of '' a solution in all or part of the concentration range indicated. - when mixed with the internal organic phase, at a concentration between 0.1 and 10% by weight of said phase and at 25 ° C, are in the form of a dispersion in all or part of the range of indicated concentration.

12. Suspension according to one of the preceding claims, characterized in that the content of nonionic polyalkoxylated surfactant and / or nonionic amphiphilic polyalkoxylated polymer, present in the external aqueous phase, is between 1 and 10% by weight relative to by weight of the reverse emulsion, preferably between 1 and 5% by weight of the reverse emulsion.

13. Suspension according to one of the preceding claims, characterized in that the amount of anionic surfactant represents 0.1 to 10% by weight of the content of polyalkoxylated nonionic surfactant and / or nonionic polyalkoxylated amphiphilic polymer.

14. Suspension according to one of the preceding claims, characterized in that the weight proportion of reverse emulsion relative to the external aqueous phase is usually between 30/70 and 90/10, preferably between 50/50 and 90/10.

15. Suspension according to one of the preceding claims, characterized in that the external aqueous phase comprises at least one polysaccharide or a mixture of polysaccharides, with a content representing 0.1 to 2% of the external aqueous phase, preferably 0, 5 to 1.5% by weight of the external aqueous phase.

16. Suspension according to one of the preceding claims, characterized in that the external aqueous phase comprises at least one preservative, with a content representing 0.1 to 1% by weight of the external aqueous phase.

17. Suspension according to one of the preceding claims, characterized in that the external aqueous phase comprises a dispersed solid, with a content representing 1 to 50% by weight of the external aqueous phase, preferably 5 to

25% by weight of the external aqueous phase.

18. Granules capable of being obtained by drying a suspension according to one of the preceding claims, consisting in bringing into contact, during a step (d), the suspension according to one of the preceding claims, with at least a desiccant.

19. Granules according to the preceding claim, characterized in that the desiccant is chosen from silica, clays, calcium carbonate, calcium phosphate, alone or as a mixture.

20. Granules according to one of claims 18 or 19, characterized in that the content of desiccant represents 5 to 40% by weight of the suspension.

21. Granules according to one of claims 18 to 20, characterized in that after step (d) a drying step is carried out at a temperature below the melting temperature of the hydrophobic compound.

22. Granules according to the preceding claim, characterized in that the drying is carried out in an oven or by means of a fluidized bed.

23. Granules according to one of claims 18 to 22, characterized in that the granules have an average size of between 100 μm to 5 mm.

24. Use of the suspension according to any one of claims 1 to 17 as an additive in formulations intended for the fields of cosmetics, dental hygiene, food, phytosanitary, exploitation of oil deposits or gas, papermaking.

25. Use of the granules according to any one of claims 18 to 23 as an additive in formulations intended for the fields of cosmetics, dental hygiene, food, phytosanitary, exploitation of oil or gas deposits , paper making.

26. Formulations intended for the fields of cosmetics, dental hygiene, food, phytosanitary, exploitation of oil or gas deposits, papermaking comprising as additives, the suspension according to the 'One of claims 1 to 17.

27. Formulations intended for the fields of cosmetics, dental hygiene, food, phytosanitary, exploitation of oil or gas deposits, papermaking comprising, as additives, the granules according to l any of claims 18 to 23.