MXPA98003135A - Pulverulent composition re-dispersable in water of polymers filmmakers prepared from single-phase unsunctively insatura - Google Patents

Abstract

The present invention relates to a pulverulent composition re-dispersible in water obtained by mixing and then drying an emulsion of at least one water-insoluble film-forming polymer, at least one principal surfactant and at least one water-soluble compound , comprising: - an emulsion of at least one water-insoluble film-forming polymer, prepared from ethylenically unsaturated monomers, - at least one principal surfactant whose binary phase-water / surfactant diagram contains an isotropic phase which is fluid at 25 ° C to a concentration of at least 50% by weight of surfactant, followed by a rigid liquid crystal phase of the hexagonal or cubic type at higher concentrations which is stable at least up to the drying temperature - at least one water soluble compound. The invention also relates to a process for preparing such a composition and to its u

Description

PULVERULENT COMPOSITION RE-DISPERSABLE IN WATER OF REPAIRED FILM FORMATS POLYMERS STARTING FROM EFFECTIVELY UNSATURATED MONOMERS DESCRIPTION OF THE INVENTION The present invention relates to water re-dispersible powders of film-forming polymers prepared from ethylenically unsaturated monomers, to a process for preparing them and to their use.

The re-dispersible powders obtained by spraying and drying dispersions of acrylic film-forming polymers, and especially the polymer dispersions of vinyl esters, are already known.

Film-forming polymers prepared from ethylenically unsaturated monomers are often used as adjuvants in inorganic hydraulic binder compositions to improve their use and their properties after curing, such as adhesion to various substrates, leak tightness, flexibility and mechanical properties.

Reversible powders have the advantage that, compared to aqueous dispersions, they can be premixed with cement in the form of ready-to-use powder compositions which are usable, for example, for the manufacture of mortars and concretes. directed to be added to construction materials, or for the manufacture of adhesive mortars or for the production of protective and decorative coatings for the interior or exterior of buildings. To achieve the success of obtaining powders that do not agglomerate during storage through the effect of pressure and temperature and which are satisfactorily reusable in water, relatively large amounts of substances are usually added. inert and protective colloids to them. Therefore, it has already been proposed to add to the dispersions, before spraying, melamine / formaldehyde / sulphonate condensation products (US-A-3784648) or na f t al ent o / f o rma ldehyde / su 1 f onat o (DE-A-3143070) and / or vinylpyrrole idone / vinyl acetate copolymers (EP-078449).

French Patent FR-A-2, 245, 723, relates to a stable water dispersible preparation which is freeze-dried, and which contains a powder of a polymer latex and a water-soluble dispersing agent which is a It's gone. The object of the present invention is to provide a novel pulverulent composition which is completely or almost completely reusable in water, based on a film-forming polymer prepared from ethylenically unsaturated monomers. Another object of the present invention is to provide a powder re-spersab le of the aforementioned type which is stable to storage without agglomeration. Another object of the present invention is to provide a process for preparing the aforementioned type powders from lattices of film-forming polymer. Another object of the present invention is to provide a refractive powder of the aforementioned type which, in powder form or after re-dispersing, where appropriate, in water, in the form of a pseudolatex, can be used in all lattice application fields to produce coatings (in particular, paints, paper coating compositions) or adhesive compositions (in particular, pressure sensitive adhesives, tile adhesives). Another object of the present invention is to provide a re-dustable powder of the aforementioned type (or the pseudolatex derived therefrom) for the purposes, more specifically, of use as additives for hydraulic binders or of the mortar or concrete type. These and other objects are achieved by the present invention which relates, in effect, to a water-repellent powder composition obtained by mixing and then drying an emulsion of at least one water-insoluble film-forming polymer. at least one principal surfactant and at least one water-soluble compound, comprising: - an emulsion of at least one water-insoluble film-forming polymer prepared from monomers and ithinically unsaturated, at least one principal surfactant whose binary phase diagram of the water / surfactant contains an isotropic phase which is fluid at 25 ° C to a concentration of at least 50% by weight of the surfactant, followed by a rigid liquid crystal phase of cubic or hexagonal type at higher concentrations which is stable at least up to the drying temperature, at least one water-soluble compound. The present invention is, furthermore, a process for preparing such a pulverulent composition, consisting in: removing the water from an aqueous emulsion consisting of a water-insoluble film-forming polymer prepared by the polymerization of the aqueous emulsion and containing at least a main surfactant, and at least one water soluble compound and, when appropriate, at least one additional surfactant or cake antiformer, and drying the dry residue to a powder of desired particle size. The composition according to the invention has the advantage of spontaneously re-dispersing in water, to give an emulsion which again has a particle size close to that of the initial emulsion. Other advantages and aspects of the invention will be more clearly evident after reading the description and the examples that are presented below. The invention relates, first of all, to a water-repellent powder composition obtained by mixing and then drying an emulsion of at least one water-insoluble film-forming polymer, at least one principal surfactant, and at least one water-soluble compound, comprising: - an emulsion of at least one water-insoluble film-forming polymer prepared from ethylenically unsaturated monomers, at least one principal surfactant whose binary phase diagram of the water / agent The surfactant contains an isotropic phase that is fluid at 25 ° C up to a concentration of at least 50% by weight of the active agent, followed by a rigid liquid crystal phase of cubic or hexagonal type at higher concentrations than at least one water-soluble compound is stable at least up to the drying temperature. The water-insoluble film-forming polymers are prepared from ethylenically unsaturated monomers, in particular of the vinyl and / or acrylate type. Water-insoluble film-forming polymers are preferably vinyl acetate or acrylate homopolymers or vinyl acetate copolymers, styrene / butadiene, styrene / acrylate, acrylate and tyrosine / butadiene / Acrylate The film-forming polymers preferably have a glass transition temperature of between about -20 ° C and + 50 ° C, preferably between 0 ° C and 40 ° C. These polymers can be prepared in a manner known per se, by polymerizing the emulsion of the ethylenically unsaturated monomers using polymerization initiators and in the presence of normal emulsifying and / or dispersing agents. The polymer content in the emulsion is generally between 30 and 70% by weight, and more specifically between 35 and 65% by weight.

As monomers, vinyl esters, and more especially vinyl acetate, may be mentioned; alkyl acrylates and methacrylates in which the alkyl group contains from 1 to 10 carbon atoms, for example, the methyl, ethyl, n-butyl and 2-ethylhexyl acrylates and methacrylates; and vinylaromatic monomers, especially styrene. These monomers can be copolymerized with one another or with other ethylenically unsaturated monomers. As non-limiting examples of monomers which may be copolymers with vinyl acetate and / or acrylic esters and / or styrene, there may be mentioned ethylene and olefins such as isobutene / the vinyl esters of branched or unbranched monocarboxylic acids. saturated ones having from 1 to 12 carbon atoms, such as vinyl propionate, "Versatate" (registered trademark for branched Cg-C ^ acid esters), pivaloate and laurate; the esters of the unsaturated dicarboxylic or monocarboxylic acids having 3 to 6 carbon atoms with the alkanols having 1 to 10 carbon atoms, such as the maleates and fumarate of methyl, ethyl, butyl and ethylhexyl; vinylaromatic monomers such as methylesterines and vinyls toluenes; vinyl halides such as vinyl chloride and vinylidene chloride, and diolefins, especially butadiene. The polymerization of the emulsion of the monomers is carried out in the presence of an emulsifier and a polymerization initiator. The monomers used can be introduced as a mixture or separately and simultaneously to the reaction medium, either all at once before the start of the polymerization or during the polymerization in successive fractions or in a continuous form. As the emulsifying agent, the additional anionic agents, represented in particular by the salts of fatty acid, alkylsulfates, are used, as well as their salts, alkylarylsulphates, alkylarylsulfonates, arylsulfonates, The sulfur compounds, sulphonate salts, alkali metal salts, and salts of abietic acid, hydrogenated or otherwise, are available. They are used in the proportions of 0.01 to 5% by weight with respect to the total weight of the monomers. The polymerization initiator of the emulsion, which is soluble in water, is represented in a more special way by the hydroperoxides such as hydrogen peroxide, eumenohydroperoxide, diperoxypropylene hydroperoxide and paramentane hydroperoxide, and by the persulphates such as Sodium persulfate, potassium persulfate and ammonium persulfate. It is used in amounts between 0.05 and 2% by weight of the total weight of the monomers. These initiators are optionally used in combination with a reducing agent such as sodium bisulfite or sodium aldehyde formula, sodium, sugars, ie, dextrose or sucrose, and metal salts. The amounts of the reducing agent used vary from 0 to 3% by weight with respect to the total weight of the monomers. The reaction temperature, which depends on the initiator used, is generally between 0 and 100 ° C, and preferably between 30 and 70 ° C. It is possible to use a transfer agent in proportions ranging from 0 to 3% by weight with respect to the monomer or monomers, generally chosen from among mercaptans such as N-dodecyl mercaptide and tertiary cellulose; cyclohexene; and halogenated hydrocarbons, such as chloroform, bromoform and carbon tetrachloride. It allows the proportion of grafted polymer and the length of the grafted molecular chains to be adjusted. It is added to the reaction medium either before polymerization or during polymerization. According to a preferred embodiment of the invention, the film-forming polymer of the composition according to the invention has a surface that is only slightly carboxylated, and therefore has a low level of surface acidity. Therefore, it preferably has a surface acidity level of not more than 100 mi c roequi val ent of the functions -COOH per gram of polymer, preferably not more than 50 microequivalent s of the -COOH functions per gram of polymer. The composition according to the invention further comprises at least one main surfactant whose water / surfactant binary phase diagram contains an isotropic phase which is fluid at 25 ° C to a concentration of at least 50% by weight of surfactant, followed by a rigid liquid crystal phase of cubic or hexagonal type at higher concentrations that is stable at least up to the drying temperature. The description of these phases are given in the work of R.G. Laughlin entitled "The AQUEOUS PHASE BEHAVIOR OF SURFACTANTS" - Academic Press -1994. Its identification by means of diffraction radiation (X-rays and neutrons) is described in the work of V. Luzzati entitled "BIOLOGICAL MEMBRANES, PHYSICAL FACT AND FUNCTION" - Academic Press - 1968. More specifically, the phase of rigid liquid crystal of the The main surfactant is stable up to a temperature equal to at least 60 ° C. According to a preferred embodiment of the invention, the rigid liquid crystal phase is stable at a temperature equal to at least 55 ° C. It can be noted at this point that the isotropic phase of fluid can be emptied, while the rigid liquid crystal phase can not be emptied. The main surfactant may be of the non-ionic or ionic type. According to a particular embodiment of the invention, such a main surfactant is ionic. p According to a first preferred embodiment of the invention, the main surfactants having a binary phase diagram as described above and chosen from the ionic glycolipid surfactants are employed. Among the ionic glycolipid surfactants, the uronic acid derivatives are used more particularly. The uronic acids corresponding to the following general formula represent a particularly advantageous embodiment of the invention: CHO I (CHOH) C02H where n represents an integer ranging from 1 to 4. Examples of compounds of this type are, in particular, galacturonic, glucuronic, D -mannuronide, L-iduronic and L-guluronic acids, without being limited, however, to these acids . The hydrocarbon chain of the surfactant which can be substituted or unsubstituted is a saturated or unsaturated chain containing from 6 to 24 carbon atoms, and preferably from 8 to 16 carbon atoms. The compounds derived from galac uronic and glucuronic acids can be used more especially. The description of these products as well as a process for preparing them is described, in particular, in Patent Application EP 532,370. According to a preferred embodiment of the invention, the galacturonic acid derivatives in the salt form are used as the main surfactants. More specifically, the hydroxyl group carried by the carbon bound to the oxygen in the ring is replaced by an OR group in which R represents a linear or branched alkyl radical having from 9 to 22 carbon atoms. On the other hand, the counterion of the surfactant salt is an alkali metal, an alkaline earth metal or alternatively a quaternary ammonium group in which the radicals attached to the nitrogen atom, which may be identical or different, are chosen of hydrogen and an alkyl or hydroxyalkyl radical having 1 to 6 carbon atoms.

According to a second preferred embodiment of the present invention, a principal surfactant of the amphoteric type is employed. The amphoteric surfactants suitable for carrying out the invention have, more especially, the following general formula: R - (A) a - [N - (CHR and - N - Q B B wherein the formula R represents an alkyl or alkenyl radical comprising 7 to 22 carbon atoms, R] represents a hydrogen atom or an alkyl radical comprising 1 to 6 carbon atoms, A represents a group (CO) or (OCH2CH2), n is equal to 0 or 1, x is equal to 2 or 3, and is equal to 0 to 4, Q represents a radical -R2-COO M with R2 representing an alkyl radical comprising 1 to 6 carbon atoms , M represents H, Na, K or NH4 and B represents H or Q. According to a particular embodiment, t-ioac tive agents of this type comprising at least two carboxyl groups are used. Therefore, more particularly, B represents the radical Q. The acid function of these compounds can, with the same effect, be partially or completely present in the acid form or in the activated form. Among these surfactants corresponding to the above formula, the amphoteric derivatives of alkyl polyamines, such as Amphionic XLR and Mirataine H2C-HAR marketed by Rhone-Poul ene, as well as Ampholac 7T / XR and Ampholac 7C / XR marketed by Berol Nobel , they are used in a more special way. The principal surfactants which have just been described can be used alone. However, the use of various t s ioac tive agents that belong or otherwise correspond to the same category will not constitute one of the binding of the scope of the present invention. The pulverulent composition according to the invention further comprises at least one water-soluble compound. More specifically, this compound is solid.

The water-soluble compounds can be selected, in particular, from among the inorganic species such as alkaline earth metal or alkali metal silicates and alkaline earth metal or alkali metal phosphates such as hexamethyl phosphite or sodium. The most advantageous silicates in this type of application are those that have a molar ratio of Si0 / M 0 between 1.6 and 3.5, M representing a sodium or potassium atom. The water-soluble compounds can likewise be chosen from organic species such as urea, sugars and their derivatives. Among sugars and their derivatives, mention may be made of monosaccharides (or glycoses), glycosides and polyols that are strongly despolyed. It is understood that the compounds in question will be those whose molecular weight in average weight is, more especially, less than 20,000 g / mole. Aldoeas such as glucose, mannose, galactose and ketose, such as fructose are examples of monosaccharides suitable for the present invention.

The glycosides are compounds that result from the condensation, with the elimination of water, of monosaccharide molecules with each other, or alternatively of monosaccharide molecules with non-carbohydrate molecules. Among the glycosides, preference is given to holosides, which are formed by the linking of carbohydrate units exclusively and, more especially to oligoholóe idoe (or oligoeacáridos) containing only a limited number of units, is say a number generally below 10. As examples of oligo lodos, sucrose, lactose, cellobiose and maltose may be mentioned. Suitable polyhydroxides (or polysaccharides), that is to say, strongly spiked compounds whose average molecular weights by weight, more especially less than 20,000 g / mole, are described, for example in the work of P. Arnaud entitled "cours de chimie organique" [Course in organic chemistry], published by Gauthier-Villars, 1987. As a non-limiting example of the po 1 iho l o s s strongly of epol imer i zadoe, can be mentioned dextran, starch, gum xantano and ga lac t omananos talee as guar or carob. These activated polymers preferably have a melting point above 100 ° C and a solubility in water of between 50 and 500 g / 1. Polymers of an organic nature, which originate from the polymerization of the monomers having the following general formula: Ri R. \ 1 C c / \ in which formula, radicals R1 # which may be identical or different, represent H, CH3, C02H or (CH2) n-C02H with n = 0 to 4 < They are also suitable. As non-limiting examples of compounds of this type, acrylic, methacrylic, maleic, fumaric, itaconic and crotonic acids may be mentioned. The copolymers obtained from the monomers corresponding to the aforementioned general formula and those obtained using these monomers and other monomers, especially vinyl derivatives, such as vinyl alcohols and vinylamides such as vinyl iridoxone, are also suitable for the invention. Mention may also be made of the copolymers obtained from alkyl vinyl ether and maleic acid, as well as those obtained from vinyl and maleic acid, which are described, in particular, in the Kirk-Othmer encyclopedia entitled "ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY "- Volume 18 3a. edition - Wiley ins t er sci ene e publicacin 1982. The peptide polymers derived from the polymer condensation of amino acids, in particular from the aspartic and glutamic acids, or from the diamino diacid precursors, are also suitable for invention. These polymers may be either homopolymers derived from a-tactic or glutamic acid, or copolymers, derivatives of aspartic acid and glutamic acid in any proportions, or copolymers derived from aspartic and / or glutamic acid and other amino acids. Among the amino acids that can be copolymerized, glycine, alanine, leucine, isoleucine, f-lalanine, methionine, histidine, proline, lysine, serine, threonine, cysteine, etc. can be mentioned. Preferred polystyrene rollers have a low degree of polymerization. The average molecular weight masses of these macromolecules are, more especially, less than 20,000 g / mol, and preferably between 1000 and 5000 g / mol. Naturally, it is entirely possible to contemplate the use of these different types of water soluble compounds in combination. According to another variant of the invention, the water-soluble compound is a major surface active agent. The composition of the present invention may also contain at least one additional ionic surfactant. The additional ionic acid agents may be, more especially, amphoteric surfactants such as alkylamines, alkyldimethylbenzenes, alkylamidopropylbetaines, alkylamidopropylimethylbetalines, alkyltrimethylsulphthates, derivatives of imidazoline such as alkyl amphoacetates, alkyl amphiphiacets, alkylaryl opioids, alkyl amphiphropionates, alkyl sulfates or alkyl amidopropihydroxysulins, and the condensation products of fatty acids and protein hydrolyzates.

It is likewise possible to use conventional anionic surfactants such as the water-soluble salts of alkylsulfates and alkyl ether sulphates, alkyl esters and alkyl taurides or their salts, alkylcarboxylates, alkyl sulphosuccinates or alkyls. In addition, there are 1 intact sarcos, the alkyl derivatives of protein hydrolyzates, and the esters and esters of alkyl and / or alkyl ether and alkyl and phosphate. The cation is, in general, an alkali metal or alkaline earth metal, such as sodium, potassium, lithium or magnesium, or an ammonium group NR / j. "1" with the radicals R, which may be identical or different, representing a alkyl radical substituted or otherwise with an oxygen or nitrogen atom. It is possible to add any normal additive, depending on the field of application of the compositions, to the powdery re-sable compositions according to the invention. In the pulverulent compositions according to the invention, the powder content of the film-forming polymer is advantageously between 40 and 90 parts by weight in the powder composition. According to a particular embodiment of the invention, the powder content of the film-forming polymer is at least 50 parts, preferably at least 70 parts, by weight. The amount of the main surfactant is, in general, between 1 and 20 parts by weight in the powder composition.

Preferably, this content is between 2 and 10 parts by weight. The amount of water-soluble compound is, in general, between 7 and 50 parts by weight of the pulverulent composition. According to a preferred variant, this amount is between 8 and 25 parts by weight. The weight ratio of the concentrations between the main surfactant and the water-soluble agent is, in general, between 20:80 and 90:10. If they are identical, that is to say, if the pulverulent composition according to the invention is at least one main surfactant that also functions as the water-soluble compound, the total amount of this compound naturally corresponds to the sum of the two scales mentioned above.

In the case in which the pulverulent composition of the invention comprises an additional surfactant, the weight ratio of the concentrations between the main surfactant and the additional surfactant is, in general, between 5 and 10. The composition according to The invention may further comprise, at least, a mineral filler having a particle size of less than about 10 μm, preferably less than 3 μm. As a mineral filler, it is recommended to use a filler chosen, in particular, from calcium carbonate, kaolin, barium sulfate, titanium oxide, talc, hydrated alumina, bentonite and calcium alumina or calcium (satin white) and silica. The presence of the mineral fillers favors the preparation of the powder and its storage stability avoiding the aggregation of the powder, that is to say, the cake formation thereof. This mineral filler can be added directly to the pulverulent composition, where it can arise from the process for the preparation of the composition. The amount of mineral filler may be between 0.5 and 40, preferably 2 to 20, parts by weight per 100 parts of the water-insoluble film-forming polymer powder. The pulverulent compositions obtained are stable to storage; they can easily be re-dispersed in water in the form of a pseudolatex, and used directly in the form of a powder or in the form of a pseudolatex in all known fields of lattice application. The process for preparing the powder composition will now be described. As discussed in the foregoing, the process is based on: removing the water from an aqueous emulsion consisting of a water-insoluble film-forming polymer prepared by the polymerization of the aqueous emulsion and containing at least one principal surfactant , at least one water-soluble compound and, where appropriate, at least one additional surface active agent or a cake antifoaming agent, spray the dry residue to a powder of the desired particle size.

Of course, in the case where normal additives are used, they can be added during the formation of the emulsion. The process is started from an aqueous emulsion of the powder of the water-insoluble film-forming polymer, obtained by the polymerization of the emulsion as defined above. This type of emulsion is commonly referred to as a latex. To this aqueous emulsion are added the other components of the pulverulent composition: the main surfactant, the water-soluble compound, when appropriate, the additional surfactant and / or the cake antiforming agent. The respective contents of the various constituents are chosen so that the dry pulverulent compositions have the composition defined above. Preferably, the process starts from an emulsion having a dry extract (film-forming polymer + surfactant + water-soluble compound + additional surfactant + cake antiforming agent) of between 10 and 70% by weight, even more preferably between 40 and 60%.

The water in this emulsion is then removed and the product obtained is sprayed in order to obtain a powder. The steps of removing the water from the latex emulsion and obtaining a powder can be separate or concomitant. Therefore, it is possible to use a freezing process, followed by a sublimation step, or of a freezing, drying or spray drying (spray drying). Spray drying is the preferred process, since it allows the powder to have the desired particle size to be obtained directly without including the grinding step. The particle size of the powder is generally less than 500 μm. The spray drying can be carried out in the usual way in any known apparatus, such as, for example, a spraying tower which combines sprinkling, effected by means of a nozzle or a centrifugal impeller with a stream of hot gas. The hot gas inlet temperature (generally air) in the head of the column preferably is between 100 and 115 ° C and the outlet temperature preferably is between 55 and 65 ° C. The mineral filler can be added to the aqueous emulsion of the starting polymer. All or part of the mineral filler can also be introduced during the spray stage in the spray drying process. Finally, it is possible to add the mineral filler directly to the final pulverulent composition. In most caoe, the powder compositions according to the invention are completely reusable in water at room temperature by simple agitation. It is understood that completely re-dispersible refers to a powder according to the invention which, after the addition of the appropriate amount of water, makes it possible to obtain a pseudolatex whose particle size is its tanc ially identical to the size of the particle. latex present in the starting emulsion. The invention also relates to the pseudolatex obtained by the re-spe sion in water of a pulverulent composition as defined above.

Finally, the invention relates to the use of pulverulent compositions previously described in the construction industry as additives to inorganic hydraulic binder mixtures for the production of protective and decorative coatings, adhesive mortars and adhesive cements directed to fix tiles and roofs of the floor. They have proved to be especially useful for the preparation of ready-to-use powder products based on cement and also on and so on. The pulverulent compositions of the invention, or the pseudocells derived therefrom, can also be used in all other fields of lattice application, more especially in the field of additives, paper and printing presses. of paintings. The powder compositions according to the invention may also contain normal additives, in particular biocides, my crobi tates, organic bac teria and organic and silicone antifoams. The following examples illustrate the invention without, however, limiting its scope.

EXAMPLES EXAMPLE 1 The following emulsion is prepared in a mixer: Compos i c ion% by weight Latex is styrene / but adieno (*) 80 (decil D -galactosid) sodium uronate (**) water 10 (*) This latex has an extract from 50% and was obtained by the polymerization of the emulsion of a mixture of 58% by weight of styrene and 42% by weight of butadiene. Its average particle size measured in a BrookhavenR is 0.12 μm. Its surface is only slightly carboxylated: it has a surface charge equal to 30 microequi-valent of the functions -COOH / gram of polymer. (**) (decyl D-galactosid) sodium uronate is marketed by the company ARD. The binary water / surfactant part diagram contains an isotropic phase which is fluid at 25 ° C to a concentration of 60% by weight of the teneion, followed by a hexagonal liquid crystal phase. Eeta faee hexagonal has been identified and characterized by X-ray diffraction of small angle, according to the work of B. Luzzati entitled "BIOLOGICAL MEMBRANES, PHYSICAL FACT AND FUNCTION", from an aqueous solution containing 62% by weight of surfactant agent. The small-angle X-ray diffraction spectra contains two thin lines whose Bragg separations are in the scale of l: l / (3) 1/2. This lattice parameter is obtained by measuring the separations of the lines that is equal to 47 Angstrom units. 1 g of this emulsion was atomized under the normal conditions of a NIROR atomization column (115 ° C at the inlet and 60 ° C at the outlet). The emulsion was co-atomized in the presence of a kaolin dispersion so that the amount of kaolin in the final product is 12% by weight. The final product takes the form of a voidable powder composed of more or less spherical particles having the following characteristics: the particle size is between 10 and 100 μm, - the dry extract of the powder is 99%, the composition by weight of the dry powder is as if: latex of reindeer / but adi eno 70% (decil D-galact os id) uronate of eodium 17% kaolin 12% water 1% The atomized product spontaneously re-disperses in water at room temperature. The average particle size of the obtained emulsion, measured using a Brookhaven® granulometer, ee of 0.13 μm.

EXAMPLE 2 The following emulsion was prepared in a mixer: Compoe i c ion% by peeo Latex es pt i reno / bu t adi o n 77.5 alkylaminocarboxylate (*) 22.5 (*) The alkylpolyaminocarboxylate is marketed under the trademark AMPHIONIC XL. This surfactant is in solution in water and has an extract in eeco equal to 40% by weight. The binary phase diagram in water / soil-active agent contains an isotropic phase which is fluid at 25 ° C to a concentration of 50% by weight of surfactant, followed by an optically isotropic viscous liquid phase of the cubic type, this phase has been identified and characterized by small-angle X-ray diffraction in an aqueous solution containing 52% surfactant. The small-angle X-ray diffraction spectrum contains a series of five characteristic lines. This latex is the same as that of Example 1. The mixture is atomized using a BUCHIR device with an inlet temperature of 110 ° C and an outlet temperature of 70 ° C. The powder obtained after atomization shows spontaneous dispersion in water. The obtained pseudolatex has a particle size identical to that of the starting latex.

EXAMPLE 3 The following emulsion was prepared in a mixer: Co-position% by weight Stretch latex / butene 80 (decyl D-galactoid) eonate dioxide 2 lactoea 8 water 10 Latex is the same as in Example 1. This mixture was atomized using a BUCHIR device with an inlet temperature of 110 ° C and an outlet temperature of 70 ° C. The powder obtained after atomization shows spontaneous dispersion in water. The obtained pseudolatex has a particle size identical to the starting latex.

EXAMPLE 4 The following emulsion was prepared in a mixer: Composition% by weight latex of sodium / butadiene 82 (decyl D-galacdos id) sodium uronate 2 urea 2 eodium silicate 14 The latex is the same as in Example 1. Sodium eilicate has a ratio of Si 2 / Na 2? equal to 2. It is in solution in water (the extract eeco is equal to 45% by weight). The sodium silicate is first mixed with the sodium (decyl D-galactosid) uronate and the urea, and the mixture is then added to the latex / butyl ether, allowing a fluid dispersion to be obtained. This mixture is then sprayed using a BUCHIR device with an inlet temperature of 110 ° C and an outlet temperature of 70 ° C. The powder obtained after atomization shows spontaneous dispersion in water. The obtained pseudolatex has a particle size identical to that of the starting latex.

EXAMPLE 5 The following emulsion is prepared in a mixer: Composition% by weight latex of iodine / but adiene 80 (decyl D-galactones id) sodium uronate 2 urea 2 hexame t af f or sodium 6 water 10 The latex is the same as in Example 1. Sodium hexametafine is first mixed with sodium (decyl D-galactosid) uronate and urea, and this mixture is then added to the latex / butentatum. eno This mixture is atomized using a BUCHIR die with an inlet temperature of 110 ° C and an outlet temperature of 70 ° C. The powder obtained after atomization shows spontaneous dispersion in water. The obtained pseudolatex has a particle size identical to that of the starting latex.

Claims (27)

1. A pulverulent composition re-dispersible in water, obtained by mixing and then pouring into an emulsion, comprising: an emulsion of at least one. water-insoluble film-forming polymer prepared from ethylenically unsaturated monomers, at least one main surfactant whose binary water / surfactant phase diagram contains an isotropic phase which is fluid at 25 ° C haeta a concentration of at least 50% by weight of the surfactant, followed by a rigid liquid crystal phase of the hexagonal or cubic type at higher concentrations than is stable at least up to the drying temperature, at least one water-soluble compound that is identical to, or different from the main surfactant.

2. The pulverulent composition according to the preceding claim, characterized in that the water-insoluble film-forming polymer is chosen from two vinyl or acrylate and vinyl acetate homopolymers, styrene / butadiene, ethane / acrylic, and lat. or, acrylate and copolymers of irene / butadiene / acrylate.

3. The pulverulent composition according to any of claims 1 and 2, characterized in that the water-insoluble film-forming polymer has a surface acidity level of not more than 100 ml of the polymer coefficient -COOH per gram of the polymer.

4. The pulverulent composition according to any of the preceding claims, characterized in that the rigid liquid crystal phase of the main surfactant is stable up to a temperature equal to at least 60 ° C, preferably up to a temperature equal to 1 or less 55 ° C.

5. The pulverulent composition according to any of the preceding claims, characterized in that the main surfactant is ionic.

6. The pulverulent composition according to claim 5, characterized in that the main surfactant is selected from the ionic glycolipid surfactants.

7. The pulverulent composition according to the preceding claim, characterized in that the glycolipid surfactant is selected from among uronic acid derivatives.

8. The pulverulent composition according to any of the rei indications 1 to 5, characterized in that the main surfactant is chosen from amphoteric surfactants of the following general formula: R - (A) B - [N - (CHR 1 - N - Q B B wherein the formula R represents an alkyl or alkenyl radical comprising 7 to 22 carbon atoms, R.}. _ represents a hydrogen atom or an alkyl radical comprising from 1 to 6 carbon atoms, A represents a group (CO) or (OCH2CH2), n is equal to 0 or 1, x is equal to 2 or 3, and is equal to 0 to 4, Q represents a radical -R2-COO M with R2 representing an alkyl radical comprising 1 to 6 carbon atoms, M represents H, Na, K or NH4 and B represents H or Q.

9. The pulverulent composition according to claim 8, characterized in that the main surfactant comprises at least two carboxyl groups.

10. The pulverulent composition according to any of the preceding claims, characterized in that the water-soluble compound is selected from inorganic species such as alkali metal or alkaline earth metal silicates and alkaline earth metal or alkali metal phosphates.

11. The pulverulent composition according to any of claims 1 to 9, characterized in that the water-soluble compound is selected from organic species such as urea, sugars and their derivatives.

12. The pulverulent composition according to the preceding claim, characterized in that the sugars and their derivatives are chosen from mono saccharides, glycosides and po lids of strongly spiked.

13. The pulverulent composition according to any of claims 1 to 9, characterized in that the water-soluble compound is chosen from polielec rol i t oe of an organic nature that originates from the polymerization of the monomers having the following general formula: R «\ / c / R, where in the formula, the radicals i? ±, which may be identical or different, represent H, CH3, C02H or (CH2) n-C02H with n = 0 to 4.

14. The pulverulent composition according to any of claims 1 to 9, characterized in that the water-soluble compound is a major surfactant.

15. The pulverulent composition according to any of the preceding claims, characterized in that it may also comprise at least one additional ionic surfactant.

16. The pulverulent composition according to any of the preceding claims, characterized in that the content of the water-insoluble film-forming polymer is between 40 and 90 parts per minute in the powder composition.

17. The pulverulent composition according to any of the preceding claims, characterized in that the amount of the main surfactant is between 1 and 20 parts by weight of the pulverulent composition.

18. The pulverulent composition according to any of the preceding claims, characterized in that the amount of the water-soluble composition is between 7 and 50 parts by weight of the pulverulent composition.

19. The pulverulent composition according to any of claims 15 to 18, characterized in that the ratio by weight of the concentrations between the main surfactant and the additional surfactant is between 5 and 10.

20. The pulverulent composition according to any of the preceding claims, characterized in that the ratio by weight of the concentrations between the main surfactant and the water-soluble compound is between 20:80 and 90:10.

21. The pulverulent composition according to any of the preceding claims, characterized in that it also comprises a mineral powder filler of smaller particle size of 10 μm, preferably less than 3 μm.

22. A process for preparing a pulverulent composition as defined in any of claims 1 to 21, characterized in that: - the water is removed from an aqueous emulsion consisting of a water-insoluble film-forming polymer prepared by the polymerization in the aqueous emulsion and containing at least one major surfactant, at least one water-soluble compound and, where appropriate, at least one additional surfactant or anti-cake-forming agent, - and the dried residue is sprayed to a powder of a desired particle size.

23. The process according to the preceding claim, characterized in that the aqueous emulsion has a dry extract of between 30 and 70% by weight.

24. The process according to any of claims 22 and 23, characterized in that the process chosen is the spray drying process.

25. The process according to the preceding claim, characterized in that all or part of the mineral filler is added to the aspers ion stage.

26. A pseudolatex obtained by the re-dispersion in water of the pulverulent composition as defined in any of claims 1 to 21.

27. The use of the pseudocellos iae defined in claim 26, and the pulverulent compositions as defined in claims 1 to 21, as additives for hydraulic binders, adhesives, compositions containing paper and paints. SUMMARY OF THE INVENTION The present invention relates to a pulverulent, water-reusable composition obtained by mixing and then drying an emulsion of at least one water-insoluble film-forming polymer, at least one principal surfactant and at least one soluble compound in water, comprising: - an emulsion of at least one water-insoluble film-forming polymer, prepared from ethylenically unsaturated monomers, at least one principal surfactant whose water / water-phase binary phase diagram contains a phase isotropic which is fluid at 25 ° C up to a concentration of at least 50% by weight of the tisation agent, followed by a rigid liquid crietal type of the hexagonal or cubic type at higher concentrations which is stable at least the drying temperature, - at least one compound soluble in water. The invention also relates to a process for preparing such a composition and to its use.