WO2001019883A1

WO2001019883A1 - Water dispersion of fluorinated latex

Info

Publication number: WO2001019883A1
Application number: PCT/FR2000/002542
Authority: WO
Inventors: Claudine Biver; Jean-Marc Corpart; Ludwik Leibler; Jean-Claude Razet
Original assignee: Atofina
Priority date: 1999-09-14
Filing date: 2000-09-13
Publication date: 2001-03-22
Also published as: FR2804440A1; AU7429600A

Abstract

The invention concerns water dispersions or fluorinated and/or hydrocarbon polymers stabilised by a macromolecular surfactant based on a hydrophilic polymer comprising a fluorinated sequence. The inventive dispersions contain neither micromolecular surfactant nor organic solvent. The invention further concerns the uses of such dispersions for treating water-repellent and oil-repellent surfaces.

Description

LATEX FLUORES IN MINIDISPERSION IN WATER

The invention relates to the field of aqueous dispersions of fluorinated and / or hydrocarbon polymers. It relates in particular to dispersions of fluorinated and or hydrocarbon polymers stabilized by a macromolecular surfactant and containing neither organic solvent nor micromolecular surfactant. It also relates to the mode of synthesis of such dispersions as well as their uses in the hydrophobic and oleophobic treatment of surfaces.

Fluoropolymers are used in various industries, in particular for the hydrophobic and oleophobic treatment of different substrates such as textiles, leathers, papers. These fluoropolymers are generally prepared by polymerization in an organic solvent or according to the aqueous emulsion polymerization technique. For reasons of environmental constraints, they are generally prepared by polymerization in aqueous emulsion.

The polymerization in water of fluorinated monomers and / or hydrocarbons poorly soluble in water generally requires large amounts of surfactants of different kinds to stabilize the fluorinated particles during the polymerization and also during storage. However, the presence of surfactants in coatings, in particular for the oleophobic and hydrophobic treatment of surfaces, can have drawbacks at the application level. It is therefore desirable to be able to produce coatings containing only molecules of high molecular weight.

Furthermore, the polymerization of fluorinated and / or hydrocarbon monomers very poorly soluble in water generally requires the use of a co-solvent which must be eliminated at the end of polymerization by distillation in order to have products free of volatile organic compounds and without flash point. The remaining problem to be solved is the preparation of a dispersion of fluoropolymers containing neither organic solvent nor micromolecular surfactant. Micromolecular and macromolecular surfactants such as linear polymers are commonly used in industry as stabilizers for the synthesis of polymers in emulsion, suspension or dispersion. The use of diblock or triblock copolymers has also developed in recent years as described in WO 9727222 and DE 19704714.

On the other hand, the use of polymers with pendant chains for the stabilization and polymerization of oil-in-water emulsion is more recent. The known examples are limited to the case where the polymer is grafted with hydrocarbon chains and is used, for example, to stabilize emulsions of dodecane in water or to polymerize styrene.

According to the invention, by hydrocarbon compound is meant any compound having a solubility parameter of less than 20 MPa ^y \

We have found that hydrophilic polymers having a fluorinated block can be used as a macromolecular surfactant in the preparation of aqueous dispersions of fluorinated and / or hydrocarbon polymers.

Indeed, the Applicant has found that it is possible to stabilize a fine dispersion of fluorinated and / or hydrocarbon-based monomers with a hydrophilic polymer having a fluorinated block, to polymerize said monomers and to keep the dispersion thus obtained stable. This makes it possible to obtain an aqueous dispersion of fluorinated and / or hydrocarbon polymers containing neither organic solvent nor micromolecular surfactant.

In fact, hydrophilic polymers carrying fluorinated chains tend to form aggregates in aqueous solution. The hydrophobic core of these aggregates constitutes a favorable environment for solubilizing fluorinated monomers. The subsequent introduction of an initiator into the reaction medium thus formed makes it possible to obtain latexes containing only polymers and therefore free of surfactant. This type of polymerization which is more akin to a polymerization in minidispersion than in conventional emulsion has the following advantages for fluorinated latexes: reduce or even eliminate the migration phenomena of surfactants in coatings and the harmful effects they may have on its properties;

-improve the stability of the latex both during polymerization and during storage by providing a steric protective effect, in the same way increasing its tolerance with respect to chemical agents (eg salts) and to shearing;

favoring the adsorption of the latex on the substrates which it is desired to treat by adapting the nature of the monomers constituting the hydrophilic polymer. In addition, it is expected to obtain stable latexes at very low concentrations of hydrophilic fluoropolymers because the critical aggregation concentration of such polymers is generally low. As a result, the polymer concentrations required will a priori be much lower than those currently used with surfactants. Finally, the aggregates of hydrophilic fluoropolymers constituting a medium favorable to the solubilization of fluorinated monomers, it is hoped to reduce, even eliminate, the use of cosolvents, hence a significant gain in production if the usual final stage of distillation is eliminated. solvent after polymerization and direct production of products without volatile organic compound. One of the objects of the invention is an aqueous dispersion of fluorinated and / or hydrocarbon polymers containing:

from 5 to 50% by weight of at least one polymer (A) chosen from fluorinated and / or hydrocarbon polymers, and

- from 1 to 15% by weight relative to the total weight of the polymers of at least one hydrophilic polymer (B) having a fluorinated block.

Polymer B is the only surfactant in the dispersion. The dispersion of the invention also contains less than 1% by weight of organic solvent.

The polymer (A) according to the invention is synthesized from: a) 0 to 100% by weight of one (or more) compounds (A1) having a polymerizable ethylene bond comprising a perfluoroalkyl group b) 0 to 100% by weight of an acrylic or methacrylic monomer (A2) with alkyl or alkoxyalkyl side chains of formula:

R ₃ - (R ₂ 0) _m - (C (0) CH ₂ ) _p -OOC-C (R,) = CH ₂ (I) where R, represents a hydrogen atom or a methyl radical, R ₂ is an alkylene group of length C, to C ₆ , each R2 may be different from the others

R ₃ is an alkyl group of length C, to C ₂₄ or a cycloalkyl group of length to C ₂₄ , m is an integer between 0 and 10 and p is zero or one. c) 0 to 20% by weight of at least one polar monomer (A3) d) 0 to 30% by weight of one or more monomers (A4) with a structure different from the previous ones.

Examples of the structure of the monomers (A1) can be, without limitation, the following:

R '

I (1) Rr-SO ₂ - N - R "- OCOCR '" = CH ₂

R '

(2) RFR4SO2 - N - R "- OCOCR"'= CH ₂

(3) RF ^ Cr ^ qOCOCR '"= CH ₂

where Rp represents a straight or branched perfluorinated chain, containing from 2 to 20 carbon atoms, preferably from 8 to 14 carbon atoms, R ₄ represents an alkyl radical containing from 1 to 4 carbons, R is a hydrogen atom or an alkyl group containing from 1 to 10 carbon atoms, R is an alkylene group containing from 1 to 10 carbon atoms, R '"is a hydrogen atom or a methyl group, q is an integer between 1 and 1 1. The monomers of type (A1), the structure of which differs only in the length of the perfluorinated chain Rp, can be incorporated as a mixture in the copolymer.

The preferred monomers (A1) of the invention are 2- (perfluorooctyl) ethyl acrylate or methacrylate and mixtures of 2- (perfluoroalkyl) ethyl acrylates or methacrylates comprising a C ₅ to C ₁₃ perfluoroalkyl chain .

In the case of monomers of type (A2), R3 can be linear, branched or cyclic; R ₂ is a linear or branched chain and preferably is - C2H4-; preferably, m is 0 or 1 and p is zero. Representative monomers of formula (I) are, for example, butyl methacrylate, ethyl-2-hexyl methacrylate, stearyl and behenyl acrylates and methacrylates, ethoxyethyl acrylate and methacrylate.

The preferred monomers (A2) of the invention are stearyl acrylate or methacrylate and behenyl acrylate.

The polar monomers of type (A3) can be nonionic or ionic.

As nonlimiting examples of nonionic monomers, mention may be made of: N-vinyl pyrrolidone-2 and its derivatives, acrylamide and methacrylamide and their derivatives, polyethylene glycol or ethylene glycol acrylates or methacrylates.

As examples of ionic or ionizable monomers by variation of the pH, there may be mentioned:

Acrylic acid and methacrylic acid and their alkali metal or quaternary ammonium ion salts, sulfonated monomers such as for example sodium vinyl sulfonate, sodium styrene sulfonate and 2-acrylamido-2-methyl acid -sulfonic, vinylpyridinium halides, acrylates and methacrylates of amino alcohols corresponding to the following formulas:

HO-Y-NR ₅ R ₆ or HO-YN ⁺ R ₅ R ₆ R ₇ , A ^" In which the symbols R ₅ , R ₆ , R ₇ , identical or different, each represent an alkyl or hydroxyalkyl radical containing from 1 to 4 carbons, Y represents an alkylene or hydroxyalkylene radical containing from 1 to 4 carbons and A ^" is any monovalent anion.

The monomers comprising reactive units capable of leading to chemical reactions between themselves or with other chemical groups present during the application (on the treated substrate for example) are also polar monomers included in the type monomers (A3). In particular, the monomers which can be commonly used comprise a hydroxyl group (N-methylolacrylamide or N-methylolmethacrylamide), or an epoxy group, or a tri or di alkoxysilane group, or an optionally blocked isocyanate group. Such monomers can be used in combination.

As monomers of type (A4), mention may be made, for example, of vinyl or vinylidene halides such as: vinyl chloride, or vinylidene, vinyl fluoride or vinylidene, vinyl esters such as vinyl acetate, vinyl propionate, trifluoro 2,2,2-ethyl methacrylate, isobornyl acrylate and methacrylate, acrylonitrile, styrene and its derivatives, butadiene, chloroprene, fluoroprene, isoprene and their mixtures. The hydrophilic fluoropolymer (B) used as sole surfactant consists of: (a) 0 to 80% by weight of at least one non-ionic hydrophilic monomer (B1)

(b) 1 to 75% of at least one monomer (B2) comprising a perfluoroalkyl radical, linear or branched, containing from 2 to 20 carbon atoms; and

(c) 2 to 75% of one or more ionic or ionizable hydrophilic monomer (s) (B3).

(d) 0 to 30% by weight of one or more monomers with a structure different from the previous ones (B4).

It can be obtained by radical polymerization in a precipitating medium (as described in patent application No. 96 1 5097 of 09.12.96) or by other synthetic methods which are easier to carry out and less expensive than the polymerizations allowing to obtain diblock or triblock copolymers

(anionic polymerization, for example). The monomers (B1), (B2) and (B 3) are described in patent No. 96 1 5097 incorporated by reference. The preferred monomer (B1) is acrylamide, the preferred monomers (B3) are acrylic acid, methacrylic acid, N- [2- (acryloyloxy) ethyl] -N, N, N-trimethylammonium chloride and N- [2- (methacryloyloxy) ethyl] -N, N, N-trimethylammonium. The monomers of type (B4) have a different chemical structure from the monomers (B1) to (B3). In particular, the copolymer (B) may contain a monomer with an alkyl side chain such as stearyl or palmitoyl methacrylate.

Examples of hydrophilic fluoropolymers of type B are provided by the copolymers P1 and P2, obtained by reacting acrylamide, acrylic acid and a mixture of 2- (perfluoroalkyl) ethyl methacrylate in the following proportions:

The copolymers P1 and P2 can, for example, be synthesized by a method of polymerization in a precipitating medium as described in patent application No. 96 15097 of 09.12.96).

Another subject of the invention is a process for the preparation of aqueous dispersions of fluorinated and / or hydrocarbon polymers (A) such as those described above, consisting in the dispersion in water of the mixture of monomers using an “effective” disperser such as a high pressure homogenizer, for example a valve homogenizer of the Manton Gaulin type, or an ultrasonic probe, and in the presence of a hydrophilic fluoropolymer (B) used as a macromolecular surfactant. polymerizing the mixture of monomers in the presence of an initiator at a temperature conventionally between 40 and 100 ° C. The monomer mixture consists of: a) 0 to 100% by weight of one (or more) compounds (A1) having a polymerizable ethylene bond comprising a C ₂ to C ₂₀ perfluoroalkyl group b) 0 to 100% by weight of an acrylic or methacrylic monomer (A2) with alkyl or alkoxyalkyl side chains of formula: R ₃ - (R ₂ 0) _m - (C (0) CH ₂ ) _p -OOC-C (R ₁ ) = CH ₂ ( I) where R represents a hydrogen atom or a methyl radical,

R ₂ is an alkylene group of length C, at C ₆ , each R2 may be different from the others

R ₃ is an alkyl group of length C, to C ₂₄ or a cycloalkyl group, m is an integer between 0 and 10 and p is zero or one. c) 0 to 20% by weight of at least one polar monomer (A3) d) 0 to 30% by weight of one or more monomers (A4) with a structure different from the previous ones.

R

I (1) RFSO ₂ - N - R "- OCOCR"'= CH ₂

R

I (2) RFR4SO ₂ - N - R "- OCOCR" = CH ₂

(3) Rp- (CH ₂ ) qOCOCR "'= CH2 where Rp represents a straight or branched perfluorinated chain, containing from 2 to 20 carbon atoms, preferably from 8 to 14 carbon atoms, R ₄ represents an alkyl radical containing from 1 to 4 carbons, R 'is a hydrogen atom or an alkyl group containing from 1 to 10 carbon atoms, R "is an alkyl group containing from 1 to 10 carbon atoms, R '" is a hydrogen atom or a methyl group, q is an integer between 1 and 1 1. The monomers of type (A1), the structure of which differs only in the length of the perfluorinated chain Rp, can be incorporated as a mixture in the copolymer. The preferred monomers (A1) of the invention are 2- (perfluorooctyl) ethyl acrylate or methacrylate and mixtures of 2- (perfluoroalkyl) ethyl acrylates or methacrylates comprising a C ₅ to C ₁₃ perfluoroalkyl chain .

The polar monomers of type (A3) can be nonionic or ionic.

Acrylic acid and methacrylic acid and their alkali metal or quaternary ammonium ion salts, sulfonated monomers such as for example sodium vinyl sulfonate, sodium styrene sulfonate and 2- acrylamido-2-methyl-sulfonic, vinylpyridinium halides, acrylates and methacrylates of amino alcohols corresponding to the following formulas:

As monomers of type (A4), mention may be made, for example, of vinyl or vinylidene halides such as: vinyl chloride, or vinylidene, vinyl fluoride or vinylidene, vinyl esters such as vinyl acetate, vinyl propionate, trifluoro 2,2,2-ethyl methacrylate, isobornyl acrylate and methacrylate, acrylonitrile, styrene and its derivatives, butadiene, chloroprene, fluoroprene, isoprene and their mixtures. The hydrophilic polymer B is that described above. By way of non-limiting illustration, an embodiment of the process of the invention is described below.

The preparation of the aqueous dispersion is obtained by mixing the hydrophilic fluoropolymer, the monomers to be dispersed and water. The monomers are dispersed by adding mechanical energy.

To facilitate the dispersion, the procedure is carried out in 2 stages: a) in the first step, the hydrophilic fluoropolymer (B) used as stabilizer of the dispersion is dissolved in water at room temperature. Liquid monomers at temperature ambient can be poured as in the stirred aqueous phase. In the case of monomers crystallized at room temperature, the mixing is carried out at a temperature above the melting point of the monomers and preferably below 65 ° C. A pre-dispersion is prepared using a high shear agitator of the rotor-stator type (for example an Ultra Turax agitator) and leads to particles of size close to one micron which tend to sediment. b) The ^2nd step aims to obtain smaller dispersed particles (≈ 100 nm) which will not sediment quickly. It consists in homogenizing the pre-dispersion using a high pressure homogenizer with Manton Gaulin valves. The dispersion thus obtained contains between 20 and 30% by weight of monomers between 1.5 and 2% of hydrophilic fluoropolymer (B) and the balance with 100% of water. The polymerization of the monomers is carried out in batch, under nitrogen circulation. To initiate the polymerization reaction, catalysts or mixtures of catalysts capable of producing free radicals, such as peroxygenated compounds, such as sodium, ammonium or potassium persulfate, alkaline perborates, hydrogen peroxide, hydrogen peroxide, can be used. sodium or barium, cumene hydroperoxide, butyl hydroperoxide, benzoyl peroxide, peracetic acid, amine oxides, ceric and ammonium nitrate, azo compounds such as azo 2, 2 'bis-isobutyronitrile, azo -2, 2 'bis

(2,4-dimethyl-4-methoxy-valeronitrile), azo-4,4 'bis (4-cyano-pentanoic acid) or its alkaline salts, di-azo-2,2' di-isobutyramidine hydrochloride. The amounts to be used can vary between 0.01 and 5% relative to the weight of the monomers to be copolymerized, preferably from 0.1 to 1.5%. The initiator preferably used is azo 2, 2 'bis-isobutyronitrile.

The copolymerization is generally carried out at a pH ranging from 2 to 9 and at a temperature between 40 ° and 100 ° C, preferably between 50 ° and 95 ° C. However, it is possible to operate at higher or lower temperatures. For example, the use of redox catalysts, such as the persulfate-ferrous salt, persulfate-hydroxy-methanesulfinate sodium systems, water oxygenated-bisulfite, hydrogen peroxide-butane-dione-2,3, can be useful to activate the reaction or lower the temperature of copolymerization. The reaction can also be initiated under radiation, for example, with a mercury or sodium lamp. The maximum conversion rate is usually reached in 30 minutes.

The copolymers used according to the invention can be presented according to different types of structure. They can be homogeneous or have a segmented or heterogeneous shape. They can also consist of mixtures of homopolymers or fluorinated or non-fluorinated copolymers. The term copolymer used in the present invention encompasses all of these structures, as well as all types of copolymers known to those skilled in the art.

In order to regulate the molecular weight of the copolymers, chain transfer agents can be used, such as alkyl mercaptans such as tert-dodecyl-mercaptan, N-dodecyl-mercaptan, N-octyl-mercaptan, carbon tetrachloride, carbon tetrabromide, chloroform, triphenylmethane. The amounts to be used can vary from 0.01% to 3% relative to the weight of the monomers, and preferably between 0.05% and 0.5%. We preferentially use N-dodecylmercaptan.

The dispersion and polymerization of fluorinated or / and hydrocarbon monomers are thus obtained without using a cosolvent, and without forming preflocs, unlike conventional methods of polymerization of this type of molecules. The usual final distillation step of the solvent is then avoided and a product free of volatile organic compound (C.O.V.) is directly obtained.

The present invention also relates to the use of the dispersions of fluorinated and / or hydrocarbon polymers according to the invention for the hydrophobic and oleophobic treatment of a wide variety of supports, such as carpets, rugs, wall coverings, leathers, papers, materials for construction such as bricks, tiles, natural or reconstituted stones, ceramics, plasters, concretes, cements, mortars, wood, glass, metals and plastics. Mention may also be made of other very diverse supports such as, for example, woven or non-woven articles based on cellulose or regenerated cellulose, natural, artificial or synthetic fibers such as cotton, cellulose acetate, wool. , the silk, polyamide, polyester, polyolefin, polyurethane or polyacrylonitrile fibers.

The dispersions according to the invention can be applied, after dilution with water, using techniques known to those skilled in the art, for example, by coating with a doctor blade, a brush or a roller, impregnation, immersion, spraying, padding or coating. The amount of dispersion to be used varies within wide limits depending on the nature of the support and the fluorine content of the dispersion. Depending on their nature, the treated substrates can be dried at room temperature or at temperatures up to 200 ° C.

To obtain a particular effect or better fixation, it may be advantageous on certain supports to combine the dispersions according to the invention with certain additives such as fixing resins, catalysts, anti UV, fungicides, antistatic agents, anti-foaming agents, etc. .. For the treatment of leathers, the application of the diluted dispersions can be carried out according to different techniques, for example by spraying. You can also operate in full bath in a fuller or a sewing machine during the last stage of the wet process. The amount of fluorinated copolymer (A) applied is generally between 1 and 10 g of dry copolymer / m ² . The leathers are preferably dried at room temperature or at a moderate temperature of up to about 100 ° C.

Textile articles are, for example, commonly treated in padding baths containing a composition according to the invention diluted in water to a concentration of copolymer (A) conventionally between 4 and 20 g / l. The fabrics are then dried and optionally heat treated at a temperature of, for example, between 120 and 200 ° C. In order to give textile substrates additional characteristics, various ingredients can be added to the compositions according to the invention, such as: catalysts capable of promoting crosslinking of the copolymers with the substrate, thermally condensable products, reactive extenders comprising, for example, blocked isocyanate groups , water repellents, flame retardants, fungicides, antistatic, softeners, buffering agents, sequestering agents, bulking agents, optical bleaching, vinyl or acrylic latexes, polyalkylenes, polyglycols, colloids.

In the case of paper and cardboard, the compositions according to the invention can be applied either in the mass, ie added to the paper pulp, or superficially on the support already finished, using a press gluing machine, for example. To obtain the desired hydrophobicity and oleophobicity characteristics, the dispersions according to the invention are applied, diluted in water, to a concentration of copolymer conventionally of the order of 0.2 to 2% relative to the weight of fibers of cellulose. In the case of mass application, a retention agent of the cationic polymer type (for example a polyamidoamine) can be added to the paper pulp before the addition of the fluorinated copolymer, so as to limit the loss of the fluorinated copolymer in white water, when the sheet of paper is formed. A completely satisfactory retention of the fluorinated copolymer (of the order of 80% and more) is generally achieved for an amount of retention agent of between 0.1 and 2% relative to the weight of fibers. To obtain a good fixing of the copolymers according to the invention on the papers and / or the cardboards on which they are applied and to give in addition a particular effect, it may also be advantageous to combine them with other adjuvants, polymers, products thermally condensable and catalysts capable of promoting their crosslinking with the support. As such, there may be mentioned starches, polyvinyl alcohols, condensates and precondensates of urea formaldehyde or melamine formaldehyde, epoxy derivatives, polyamine-epichlorohydrin resins, glyoxal and its derivatives. The treated papers are dried under the conditions conventionally used used in stationery, ie at a temperature of the order of 90 to 130 ° C. These fluorinated dispersions are applicable on paper according to different techniques (in size-press or in the mass) and give it excellent hydrophobic and oleophobic properties, in particular a spectacular resistance to liquids of aqueous origin, to fatty substances as well as 'with solvents of low surface tension. Such papers are used, for example, for the labeling of oil bottles or in the packaging of wet and / or fatty food products in markets as varied as the biscuit / pastry, fast food, the margarine and butter market, the meat and poultry market, the chocolate sector, frozen products, the dry food market for dogs and cats (pet food).

The hydrophobic and oleophobic performances of the substrates treated according to the invention are measured by means of conventional oleophobia and hydrophobia tests for those skilled in the art.

The following examples illustrate the invention without limiting it.

Examples

Example 1 a) preparation of the aqueous dispersion

7 g of hydrophilic fluoropolymer P1 are dissolved in 238 g of water.

The solution is brought to 40 ° C. 105 g of a mixture of 2-

(perfluoroalkyl) ethyl CH2 = CH-COO-C ₂ H ₄ - (CF ₂ ) _n CF ₃ with n between 5 and 13

(type A1 monomers) (0.185 mol) preheated to 40 ° C. are poured into this solution with mechanical stirring.

The pre-dispersion is carried out using Ultra Turax for 3 minutes between 10 and 20,000 rpm depending on the foaming level. The system obtained is opalescent and slightly suspicious.

This dispersion is then homogenized by carrying out 10 passages with Manton Gaulin at a pressure of 1,000 bars. The final dispersion obtained is perfectly clear, no foaming is observed. a) polymerization of the fluorinated monomer dispersion

221.5 g are introduced into a 0.25 liter reactor, equipped with a thermometer, a reflux condenser, an anhydrous nitrogen inlet, a dropping funnel, a mechanical stirrer. of dispersion. Stirring is started, the reaction medium is brought to the temperature of 62 ° C, under nitrogen circulation. The reaction medium is maintained at this temperature under nitrogen for 30 minutes.

A solution of 0.136 g (0.0008 mole) of azobis-isobutyronitrile in 2.67 ml of N-methyl pyrrolidone is then introduced into the reactor using the funnel, ie an initiator concentration of 0.68 % molar with respect to as a monomer, the initiation of the polymerization takes place practically upon the introduction of the initiator.

A dry extract of 30.8% is obtained in the first 30 minutes of polymerization. b) characteristics of the dispersion

The dispersion is stable stored at room temperature and at 60 ° C for at least 2 months. The average particle size measured by light scattering is between 160 and 200 nm.

Example 2: kinetics a) preparation of the aqueous dispersion

7 g of the hydrophilic fluoropolymer P1 are dissolved in 238 g of water. 105 g of 2- (perfluorooctyl) ethyl acrylate CH ₂ = CH-COO-C ₂ H ₄ - (CF ₂ ) ₇ -CF ₃ (monomer of type A1) (0.203 mole) are poured into the mechanically stirred aqueous phase . The dispersion is prepared as in Example 1 by carrying out 10 passages with Manton Gaulin at a pressure of 700 bars. The dispersion obtained is clear. b) polymerization of the fluorinated monomer dispersion

In a 0.25 liter reactor, equipped with a thermometer, a reflux condenser, an anhydrous nitrogen inlet, a dropping funnel, a mechanical stirrer, 223 g of the dispersion. Stirring is started, the reaction medium is brought to the temperature of 60 ° C, under nitrogen circulation and maintained at this temperature under nitrogen for 30 minutes.

A solution of 0.138 g (0.0008 mole) of azobis isobutyronitrile in 2.68 g of N-methyl pyrrolidone is introduced into the reactor using the funnel, ie an initiator concentration of 0.63 mol% relative to the monomer.

c) characterization of the dispersion During the polymerization, the dry extract (ES,% by weight) and the size of the particles formed are determined by light scattering (diameter mean hydrodynamics, nm). The values obtained before priming and over time after priming are indicated in the table below:

A dry extract greater than 30% is obtained from the first 30 minutes after the introduction of the initiator, the azobis isobutyronitrile. A dry extract of 31.6% is obtained at the end of polymerization. The average particle size is close to 200 nm throughout the polymerization, the polydispersity index being less than 0.15. The polymerization therefore takes place inside the particles formed during the preparation of the dispersion.

The final dispersion is stable stored at room temperature for at least 4 months and at 60 ° C for at least 15 days.

Example 3 a) preparation of the aqueous dispersion 7 g of hydrophilic fluoropolymer P2 are dissolved in 238 g of water. The solution is brought to 40 ° C.

105 g of a 50% molar mixture of a mixture of 2-

(perfluoroalkyl) ethyl CH2 = CH-COO-C ₂ H ₄ - (CF ₂ ) _n CF ₃ with n between 5 and 13 (monomers of type A1) (0.1 16 mol) and stearyl methacrylate (monomer of type A2) (0.116 mole), preheated to 40 ° C, are poured into this solution with mechanical stirring.

The dispersion is prepared as in Example 1. The dispersion obtained is white. b) polymerization of the dispersion of the monomer mixture

234.2 g of dispersion are introduced into a 0.25 liter reactor equipped as in Example 1. The reaction medium is brought to 60 ° C. with stirring and circulation of nitrogen and is kept there for 30 minutes. A solution of 0.144 g (0.0009 mole) of isobutyronitrile azobis in 2.8 ml of N-methyl pyrrolidone is introduced into the reactor, ie an initiator concentration of 0.39 mol% relative to the monomers. A dry extract of 31.5% is obtained at the end of the test. c) characterization of the dispersion

The dispersion is stable stored at room temperature for at least 2 months. The average particle size is 164 nm.

Examples 4: tests

Oleophobia tests:

The oleophobia is measured according to the test described in "AATCC Technical Manual", test method 1 18 (1992), which evaluates the non-wettability of the substrate by a series of oily liquids whose surface tensions are lower and lower. The rating of the treated substrate is defined as the maximum value of the test liquid which does not wet the support. The test liquids used in the evaluation are listed in the following table:

Hydrophobic tests The hydrophobic effect is measured using test solutions numbered from 1 to 10 and consisting of water / isopropanol (IPA) mixtures in the following weight proportions:

The test consists in depositing drops of these mixtures on the treated substrates, then observing the effect produced. The number corresponding to the solution which contains the highest percentage of isopropanol and which has not penetrated or wetted the substrate after 30 seconds of contact is noted, giving as a value.

Application on leather: The dispersion synthesized in Example 3 is diluted at room temperature with distilled water to a concentration of 1% of active materials and the solution (S1) thus obtained is deposited on the surface of samples of leather on stain by cross spraying using a Volumair T21 sprayer. The average amount of solution (S1) deposited per unit area is 160 gm ² .

The same latex is also diluted with 2% of active material to obtain the solution (S2) which is applied under identical conditions on the same support with a deposited quantity of 130 g / m ² .

After drying at room temperature for 18 hours and one hour in an oven at 80 ° C., the hydrophobic and oleophobic resistance of the treated leathers is evaluated, compared with that of untreated leathers. The results collated in the following table demonstrate the effectiveness of dispersion 3 according to the invention.

The dispersion synthesized in Example 2 is diluted at room temperature with distilled water to a concentration of 1% of active materials and the solution (S3) thus obtained is deposited on the surface of leather samples on stain by cross spraying using a Volumair T21 sprayer. During the first application test, the average amount of solution (S3) deposited per unit area is 131 g / m ² .

During a second test, the quantity deposited is 254 g / m ² .

After drying at room temperature for 18 hours and one hour in an oven at 80 ° C., the hydrophobic and oleophobic resistance of the treated leathers is evaluated, compared with that of untreated leathers. The results collated in the following table demonstrate the effectiveness of dispersion 2 according to the invention.

Claims

CLAIMS:

1. Aqueous dispersion of fluorinated and / or hydrocarbon polymers containing:

- from 1 to 15% by weight relative to the total weight of the polymers (A) of at least one hydrophilic polymer (B) having a fluorinated block, acting as sole surfactant, the dispersion additionally containing less than 1% by weight of organic solvent.

2. Dispersion according to claim 1 characterized in that the polymer (A) is obtained by polymerization of a mixture of monomers containing from: a) 0 to 100%> by weight of one (or more) compounds (A1) having a polymerizable ethylene bond comprising a C ₂ to C ₂₀ perfluoroalkyl group, b) 0 to 100% by weight of an acrylic or methacrylic monomer (A2) with alkyl or alkoxyalkyl side chains of formula:

R ₃ - (R ₂ 0) _m - (C (0) CH ₂ ) _p -OOC-C (R ₁ ) ≈ CH ₂ (I) where R, represents a hydrogen atom or a methyl radical, R ₂ is an alkylene group of length C, to C ₆ , each R2 may be different from the others

R ₃ is an alkyl group of length C, to C ₂₄ or a cycloalkyl group of length C ₆ to C ₂₄ m is an integer between 0 and 10 and p is zero or one, c) 0 to 20% by weight d 'at least one polar monomer (A3), d) 0 to 30% by weight of one or more monomers (A4) with a structure different from the previous ones.

3. Dispersion according to Claim 2, characterized in that the monomer A1 is chosen from the group containing the molecules corresponding to the following general formulas: R

I

(1) RFSO ₂ - N - R "- OCOCR" ≈ CH ₂

R

I

(2) RF 4SO ₂ - N - R "- OCOCR" = CH ₂

(3) RF- (CH2) qOCOCR "'≈ CH ₂

where Rp represents a straight or branched linear perfluorinated chain, containing from 2 to 20 carbon atoms, preferably from 8 to 14 carbon atoms, R ₄ represents an alkyl radical comprising from 1 to 4 carbons, R 'is an atom of hydrogen or an alkyl group containing from 1 to 10 carbon atoms,

R "is an alkylene group containing from 1 to 10 carbon atoms, R '" is a hydrogen atom or a methyl group, q is an integer between 1 and 1 1.

4. Dispersion according to claim 3 characterized in that the preferred monomer A1 of the invention is chosen from 2- (perfluorooctyl) ethyl acrylate or methacrylate and mixtures of 2- (perfluoroalkyl) acrylates or methacrylates ethyl having a C ₅ -C ₁₃ perfluoroalkyl chain.

5. Dispersion according to one of the preceding claims, characterized in that the monomer A2 is chosen from butyl methacrylate, ethyl-2-hexyl methacrylate, stearyl and behenyl acrylates and methacrylates, acrylate and ethoxyethyl methacrylate.

6. Dispersion according to claim 5 characterized in that the preferred monomer A2 is chosen from stearyl acrylate or methacrylate and behenyl acrylate.

7. Dispersion according to any one of the preceding claims, characterized in that the monomer A3 is chosen:

either in the group of nonionic monomers containing N-vinyl pyrrolidone-2 and its derivatives, acrylamide and methacrylamide and their derivatives, polyethylene glycol or ethylene glycol acrylates or methacrylates,

either in the group of ionic or ionizable monomers by variation of the pH, containing acrylic acid and methacrylic acid and their alkali metal or quaternary ammonium ion salts, the sulfonated monomers such as for example sodium vinyl sulfonate, sodium styrene sulfonate and 2-acrylamido-2-methyl-sulfonic acid, vinylpyridinium halides, acrylates and methacrylates of amino alcohols corresponding to the following formulas: HO-Y-NR ₅ R ₆ or HO-YN ⁺ R ₅ R ₆ R ₇ , A ^"

In which the symbols R ₅ , R ₆ , R ₇ , identical or different, each represent an alkyl or hydroxyalkyl radical containing

1 to 4 carbons, Y represents an alkylene or hydroxyalkylene radical containing from 1 to 4 carbons and A ^" is any monovalent anion.

- Or in the group containing the monomers comprising a hydroxyl group (N-methylolacrylamide or N-methyl-methacrylamide), or an epoxy group, or a tri or di alkoxysilane group, or an isocyanate group optionally blocked.

8. Dispersion according to any one of the preceding claims, characterized in that the monomer A4 is chosen from vinyl halides or vinylidene such as: vinyl chloride, or vinylidene, vinyl fluoride or vinylidene, vinyl esters such as vinyl acetate, vinyl propionate, trifluoro 2,2,2-ethyl methacrylate, acrylate and isobornyl methacrylate, acrylonitrile, styrene and its derivatives, butadiene, chloroprene, fluoroprene, isoprene and mixtures thereof.

9. Dispersion according to any one of the preceding claims, characterized in that the hydrophilic fluoropolymer (B) used as sole surfactant consists of: (e) 0 to 80% by weight of at least one nonionic hydrophilic monomer ( B1) such as acrylamide,

(f) 2 to 75% of at least one monomer (B2) comprising a perfluoroalkyl radical, linear or branched, containing from 2 to 20 carbon atoms; and (g) 1 to 75% of one or more ionic or ionizable hydrophilic monomer (s) (B3) chosen from acrylic acid, methacrylic acid, N- chloride [2- (acryloyloxy) ethyl] -N, N, N-trimethylammonium and N-

[2- (methacryloyloxy) ethyl] -N, N, N-trimethylammonium.

(h) 0 to 30% by weight of one or more monomers with a structure different from the previous ones (B4).

10. Dispersion according to Claim 9, characterized in that the said polymer B preferably consists of:

(e) 70 to 80% by weight of acrylamide, (f) 2 to 10% by weight of B2,

(g) 10 to 30% by weight of acrylic acid or methacrylic acid.

1 1. Process for obtaining a dispersion according to any one of the preceding claims, consisting of - dispersing the mixture of monomers in water using a "efficient" disperser such as a high pressure homogenizer, for example a Manton Gaulin type homogenizer with flaps, or a ultrasonic probe, and in the presence of a hydrophilic fluoropolymer (B) used as a macromolecular surfactant, the polymerization of the mixture of monomers in the presence of an initiator or of a mixture of initiators at a temperature conventionally between 40 and 100 ° C,

The mixture of monomers consisting of: a) 0 to 100% by weight of one (or more) monomer (A1), b) 0 to 100% by weight of an acrylic or methacrylic monomer (A2), c) of 0 to 20% by weight of at least one polar monomer (A3), d) from 0 to 30%> by weight of one or more monomers (A4) with a structure different from the previous ones.

12. Use of the dispersion according to one of claims 1 to 10 in the hydrophobic treatment of various supports, such as carpets, rugs, wall coverings, leathers, papers, building materials, woven or non-woven articles based on cellulose or regenerated cellulose and natural or artificial fibers.

13. Use of the dispersion according to one of claims 1 to 10 in the oleophobic treatment of various supports, such as carpets, rugs, wall coverings, leathers, papers, building materials, woven or non-woven articles based on cellulose or regenerated cellulose, and natural or artificial fibers.