FR3056984A1 - PROCESS FOR OBTAINING A COAGULUM AND A MASTER MIXTURE OF ELASTOMER AND POLYMERIC LOAD - Google Patents

Abstract

The invention relates to a method for obtaining a coagulum based on at least one elastomer and at least one polymeric filler, said process comprising the following steps: having at least one elastomer latex having a Zeta potential Z1, - having at least one aqueous dispersion of a polymeric filler having a potential Zeta Z2, the Zeta potential Z2 being of opposite sign to the Zeta potential Z1 and the difference of the potentials Zeta Z2 and Zeta Z1, in absolute value, being greater than or equal to 20 mV, - contacting and mixing the elastomer latex and the aqueous polymeric filler dispersion to obtain a coagulum, - recover the coagulum.

Description

Holder (s): COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN Limited partnership with shares, MICHELIN RECHERCHE ET TECHNIQUE S.A. Limited company.

Extension request (s)

Agent (s): MANUFACTURE FRANÇAISE DES PNEUMATIQUES MICHELIN.

FR 3 056 984 - A1 (54) PROCESS FOR OBTAINING A COAGULUM AND A MASTER MIXTURE OF ELASTOMER AND POLYMERIC FILLER.

The invention relates to a process for obtaining a coagulum based on at least one elastomer and at least one polymeric filler, said process comprising the following steps:

- have at least one elastomer latex having a Zeta Ζ _Ί potential,

- have at least one aqueous dispersion of a polymeric filler having a Zeta Z ₂ potential, the Zeta Z ₂ potential being of opposite sign to the Zeta Z- potential, and the difference of the Zeta Z ₂ and Zeta Z ₁ potentials, in absolute value, being greater than or equal to 20 mV,

- contacting and mixing the elastomer latex and the aqueous dispersion of polymeric charge to obtain a coagulum,

- recover the coagulum.

-1 The invention relates to a process for preparing a coagulum and a masterbatch in the liquid phase of one or more elastomers and one or more reinforcing polymeric fillers.

The term "masterbatch" (commonly known by its English name "masterbatch") means an elastomer-based composite into which one or more fillers and possibly other additives have been introduced.

In order to obtain the optimum reinforcement properties conferred by a load in a tire tread and thus a high resistance to wear, it is known that it is generally appropriate for this load to be present in the elastomeric matrix under a final form which is both as finely divided as possible and distributed as homogeneously as possible. However, such conditions can only be achieved insofar as this filler has a very good ability, on the one hand to be incorporated into the matrix during mixing with the elastomer and to disaggregate, on the other hand to disperse homogeneously in this matrix.

However, in order to improve the dispersibility of the filler in the elastomeric matrix, it is known to use a mixture of elastomer and filler in the liquid phase ("mixing in liquid phase" or "wet mixing" in English). To do this, it uses elastomer latex, and an aqueous dispersion of the filler, commonly called "slurry".

In this field, as early as 1955, the problem of the uniform dispersion of charges, and in particular carbon black within rubber, was already posed. Thus, document BE 541816 discloses a process for preparing a masterbatch of rubber and carbon black in the liquid phase. This process is done continuously and uses hydraulic shocks or violent mechanical agitation to achieve the dispersion of carbon black within the elastomeric matrix.

Fillers other than carbon black can be used, for example inorganic reinforcing fillers such as silica or polymeric fillers, in particular reinforcing polymeric fillers.

However, the use of these fillers in liquid mixing to obtain a masterbatch is more difficult than the use of carbon black. In fact, unlike carbon black, these polymeric fillers do not have a tendency to coagulate spontaneously with an elastomer latex.

Different solutions have been proposed to nevertheless make it possible to obtain coagulation and good dispersion of a polymeric filler, in particular a reinforcing filler, in the elastomeric matrix when using the liquid phase mixing process. One of the solutions consists in using a coagulation agent which allows solidification of the elastomer latex and of an aqueous dispersion of reinforcing polymeric filler.

For example, document EP1298166 proposes the incorporation of a polymeric reinforcing filler in the form of crosslinked rubber particles in

-2a rubber latex by adding sulfuric acid and a salt, used as a coagulation agent, to form a coagulum.

However, this method of obtaining a masterbatch has the drawback of being long and tedious, since it is necessary to wash the coagulum several times in order to remove the coagulation agents. This process also generates wash water which must be treated to avoid environmental pollution.

Furthermore, depending on the nature of the coagulation agent, in particular when the latter is a solvent, the steps of washing and drying the coagulum obtained can be at the origin of the release of volatile organic compounds (also called VOCs) which have a direct and negative impact on health.

It is therefore necessary to have a process for obtaining a coagulum and a masterbatch which is simple to implement, comprises a limited number of reaction stages and which allows the use of reagents whose toxicity is low or limited.

The applicants have surprisingly found a simple process for obtaining a coagulum and a master elastomer / polymeric filler mixture, in particular reinforcing filler, prepared by mixing in the liquid phase, making it possible to obtain a good dispersion of said filler in the elastomer matrix without generation of wash water. Advantageously, this process makes it possible in particular to achieve very good yield (greater than 80% by mass in certain cases).

The invention thus relates to a process for obtaining a coagulum based on at least one elastomer and at least one polymeric filler, said process comprising the following steps:

having at least one elastomer latex having a Zeta Zi potential, having at least one aqueous dispersion of a polymeric filler having a Zeta Z ₂ potential, the Zeta Z ₂ potential being of opposite sign to the Zeta Zi potential and the difference in Zeta Z ₂ and Zeta Zi potentials, in absolute value, being greater than or equal to 20 mV, bringing the elastomer latex and the aqueous dispersion of polymeric charge into contact and mixing to obtain a coagulum, recovering the coagulum.

Preferably, the invention relates to a process as defined above in which the elastomer is a synthetic elastomer.

Preferably, the invention relates to a process as defined above in which the synthetic elastomer results from the polymerization of at least one ethylenic monomer.

Preferably, the invention relates to a process as defined above in which the synthetic elastomer is chosen from diene elastomers and copolymers resulting from the polymerization of at least one ethylenic monomer and one monomer of vinyl esters of acids carboxylic.

Preferably, the invention relates to a process as defined above in which the synthetic elastomer is chosen from polybutadienes, synthetic polyisoprenes, butadiene-styrene copolymers, butadiene-isoprene copolymers, copolymers of butadiene-acrylonitrile, isoprene-styrene copolymers, butadiene-styrene-isoprene copolymers and copolymers of ethylene and vinyl esters of C ₂ -C ₄ carboxylic acids.

Preferably, the invention relates to a process as defined above in which the elastomer latex is obtained by radical polymerization in emulsion in aqueous phase, preferably is obtained by radical polymerization in emulsion in aqueous phase and in the presence of a ionic surfactant.

Preferably, the invention relates to a process as defined above in which the elastomer latex is obtained by emulsification in aqueous phase of a synthetic elastomer.

Preferably, the invention relates to a process as defined above in which the elastomer latex has a solid content of at least 35% by weight relative to the total weight of said elastomer latex.

Preferably, the invention relates to a process as defined above in which the aqueous dispersion of polymeric filler is obtained by radical emulsion polymerization in aqueous phase, preferably is obtained by radical emulsion polymerization in aqueous phase and in the presence of an ionic surfactant.

Preferably, the invention relates to a process as defined above in which the polymeric filler comprises a functionalized and crosslinked vinyl polymer.

Preferably, the invention relates to a process as defined above in which the functionalized and crosslinked vinyl polymer results from the copolymerization of at least:

- an aromatic or non-aromatic vinyl monomer M1,

a M2 monomer having a polymerizable unsaturated group and at least one functional group chosen from the group consisting of an epoxy group, a hydroxysilyl group, an alkoxysilyl group, a hydroxyl group, an amino group and a group a carbonyl group, and

- A crosslinking monomer M3 having at least two polymerizable unsaturated groups.

Preferably, the invention relates to a process as defined above in which the functionalized and crosslinked vinyl polymer results from the copolymerization of at least one monomer M1 is chosen from styrene and ethylvinylbenzene, a monomer M2 is chosen from trimethoxysilylpropyl methacrylate (abbreviated as MTSP), trimethoxysilylpropyl acrylate (ATSP) and trimethoxysilylethylstyrene (TSES), styrylethyl-trimethoxysilane and

-4 glycidyl methacrylate, and a monomer M3 is chosen from diisopropenylbenzene, divinylbenzene and trivinylbenzene.

Preferably, the invention relates to a process as defined above in which the amount of polymeric filler when the elastomer latex is brought into contact with the aqueous dispersion of polymeric filler ranges from 20 to 50 parts by weight per cent parts of elastomer.

Preferably, the invention relates to a process as defined above in which the step of bringing the elastomer latex into contact and mixing with the aqueous dispersion of polymeric filler does not require the addition of a coagulation agent .

Preferably, the invention relates to a process as defined above in which the elastomer latex is an anionic elastomer latex.

Preferably, the invention relates to a process as defined above in which the aqueous dispersion of polymeric charge is an aqueous dispersion of cationic polymeric charge.

Preferably, the invention relates to a process as defined above in which the polymeric filler is a reinforcing polymeric filler.

Another subject of the invention relates to a coagulum comprising at least one elastomer and at least one polymeric filler obtained according to the process defined above.

Another object of the invention relates to a process for obtaining a masterbatch comprising at least one elastomer and at least one polymeric filler, said process comprising the following steps:

- have a coagulum defined previously or obtained according to the process defined above;

- dry the coagulum to obtain a masterbatch.

Another object of the invention relates to a masterbatch comprising at least one dried coagulum and as defined above.

Preferably, the masterbatch has a rate of polymeric charge which ranges from 20 to 50 phr.

Another subject of the invention relates to a rubber composition based on at least one coagulum as defined above or based on at least one masterbatch defined above.

Another subject of the invention relates to a semi-finished or finished article comprising at least one composition defined above.

Another object of the invention relates to a tread comprising at least one composition defined above.

Another subject of the invention relates to a tire comprising at least one composition defined above.

-5I. MEASUREMENTS AND TESTS USED

1.1 Measurement of the Zeta potential

As used here, Zeta potential is a scientific term for the electrokinetic potential in colloidal systems. In the literature of colloidal chemistry, it is generally designated using the Greek letter Zeta, hence potential ζ.

Zeta potential is a measure of the magnitude of repulsion or attraction between particles. Zeta potential is an index of the extent of interaction between colloidal particles, and Zeta potential measurements are used to gain access to the stability of colloidal systems.

Most colloidal dispersions in aqueous media carry a surface charge. If acid groups are present on the surface of a particle, it will tend to develop a negative surface charge. In contrast, if basic groups are present on the surface of a particle, it will tend to develop a positive surface charge. The magnitude of the surface charge depends on the acid or basic strength of the surface groups and the pH of the solution. The surface charge can be reduced to zero by eliminating surface ionization by reducing the pH in the case of particles with a negative charge or increasing the pH in the case of particles with a positive charge. For example, surfactants can be specifically adsorbed on the surface of a particle, which leads, in the case of cationic surfactants, to a surface of positive charge, and in the case of anionic surfactants, to a negative charge surface. See "Zeta Potential an Introduction in 30 Minutes", technical note from the Zêtasizer Nano series, p. 3 (published before September 2010). The appearance of a net charge on the surface of a particle affects the distribution of ions in the surrounding interfacial region, which results in an increased concentration of counterions, ions of charge opposite to that of the particle, near the surface. Thus, there is a double electric layer around each particle. The liquid layer surrounding the particle is in two parts: an internal region (Stern layer) where the ions are strongly bound and an external region (diffuse layer) where they are less well associated. In the diffuse layer, there is an imaginary border inside which ions and particles form a stable entity. When a colloidal particle moves (eg, due to thermal agitation), the ions inside the border move with it. The ions beyond the border remain with the volume of dispersant. The boundary potential (hydrodynamic shear surface) is the Zeta potential.

From a theoretical point of view, the Zeta potential is an electrical potential in the interfacial double layer (DL) at the location of the sliding plane with respect to a point in the volume of fluid far from the interface. In other words, the Zeta potential is the potential difference between the dispersing medium and the stationary layer of fluid attached to the dispersed particle.

-6The Zeta potential is widely used for the quantification of the amplitude of the electric charge at the level of the double layer. The Zeta potential should not be confused with the electrode potential or the electrochemical potential (because electrochemical reactions are generally not involved in the appearance of the Zeta potential).

In an aqueous medium, the pH of the sample affects its Zeta potential. For example, if a base is added to a suspension with a negative Zeta potential, the particles tend to acquire a more negative charge. If sufficient acid is added to the suspension, then a point will be reached where the charge will be neutralized. Adding an additional amount of acid will cause a positive charge to build up.

Zeta potential is not directly measurable, but it can be calculated using theoretical models and electrophoretic mobility or experimentally determined dynamic electrophoretic mobility. Electrokinetic phenomena and electroacoustic phenomena constitute the usual sources of data for the calculation of the Zeta potential. However, for the purposes of this application, the Zeta potential is calculated using electrokinetic phenomena, in particular electrophoresis. Electrophoresis is used to estimate the Zeta potential of particles, while the flow potential / current is used for porous bodies and flat surfaces.

Electrophoresis is the movement of a charged particle in relation to the liquid where it is suspended under the influence of an applied electric field. When an electric field is applied through an electrolyte, charged particles suspended in the electrolyte are attracted to the opposite charge electrode. The viscous forces acting on the particles tend to oppose this movement. When equilibrium is reached between these two opposing forces, the particles move at constant speed.

The speed depends on the intensity of the electric field or the voltage gradient, the dielectric constant of the medium, the viscosity of the medium and the Zeta potential.

The speed of the particle in a unit electric field is called its electrophoretic mobility. The Zeta potential is linked to electrophoretic mobility by Henry's equation: Ue = (2eÇf (Ka)) / 3q where Ue = electrophoretic mobility, ζ = Zeta potential, ε = dielectric constant, η = viscosity and fixa) = function of Henry. The unit of k, called the Debye length, is the inverse of a length and k ' ¹ is often considered a measure of the "thickness" of the electric double layer. The parameter "a" refers to the radius of the particle, and therefore Ka measures the relationship between the radius of the particle and the thickness of the electric double layer. The electrophoretic determinations of the Zeta potential are most often made in an aqueous medium and at a

-7 moderate electrolyte concentration; f (Ka) in this case is 1.5 which corresponds to the Smoluchowski approximation.

Therefore, the calculation of the Zeta potential from mobility is simple for systems for which the Smoluchowski model is suitable, i.e. particles larger than about 0.2 pm (200nm) dispersed in electrolytes containing more than 10 ^"3 M (M = mol·l ^-1) salt. For small particles in media with a low dielectric constant (eg non-aqueous media), f (xa) becomes 1.0 and allows such a simple calculation. This is called Huckel's approximation.

Thus, the particles inside the dispersion with a Zeta potential will migrate towards the opposite charge electrode with a speed proportional to the amplitude of the Zeta potential.

The essence of a conventional microelectrophoresis system is a hair cell with electrodes at both ends to which a potential is applied. The particles move towards the electrode, their speed is measured and expressed in a unit intensity field like their mobility. This speed is measured using the laser Doppler anemometer technique. The frequency offset or phase shift of an incident laser beam caused by these moving particles is measured as the mobility of the particles, and this mobility is converted to Zeta potential by introducing the viscosity and the dielectric permittivity of the dispersant, and applying the Smoluchowski theories.

The ZETASIZER ΝΑΝΟ series available from Malvem Instruments, UK, uses a combination of laser Doppler velocimetry and scattered light phase analysis (PALS) in a patented technique called M3-PALS to measure the electrophoretic mobility of a particle.

A ZETASIZER ΝΑΝΟ series Zeta potential measurement system available from Malvern Instruments consists of six main components. First, a laser is used to provide a light source to illuminate the particles inside the sample. For Zeta potential measurements, this light source is separated to obtain an incident beam and a reference beam. The incident laser beam passes through the center of the sample cell, and light scattered at an angle of about 13 ° is detected. When an electric field is applied to the cell, any particle moving in the measurement volume causes the detected light intensity to fluctuate with a frequency proportional to the speed of the particles, and this information is transferred to a digital signal processor. then to a computer. The ZÊTASIZER ΝΑΝΟ software generates a frequency spectrum from which the electrophoretic mobility and therefore the Zeta potential are calculated. The intensity of the detected scattered light must be within a specific range for the detector to measure it correctly. To achieve this, we use an attenuator, which adjusts the intensity of the light reaching the sample and therefore the intensity of the scattering. To correct any difference in cell wall thickness

-δει refraction of the dispersant, a compensation optic is installed to maintain optimal alignment.

Unless otherwise specified, the measurement of the Zeta potential is carried out on a ZetaSizer model Nano-ZS device sold by the company Malvern Instrument, on a sample of elastomer latex or of an aqueous dispersion of a reinforcing filler (also called slurry ) diluted xlOO in a 10 ' ³ M NaCl solution

The sample preparation protocol for the Zeta potential measurement is as follows:

• Prepare 1000 mL of a NaCl stock solution to 10 ^'3 M by introducing 58 mg of NaCl in a volumetric flask of 1000 mL and complete with ultrapure water to the mark;

• Prepare the test sample by introducing 1 mL of elastomer latex or slurry into a 100 mL volumetric flask and make up to the mark with the 10 ' ³ M NaCl stock solution

• Place the sample to be tested in the ZêtaSizer model Nano-ZS device and perform the measurement.

Thus when, according to the invention, there are Zeta potentials ζι and ζ ₂ (or Zeta Zi and Zeta Z ₂ ) respectively of the elastomer latex and of the dispersion of polymeric reinforcing filler, of opposite signs, the difference of these Zeta potentials, Δζ (or ΔΖ), has an absolute value | Δζ | (or | AZ |); this value Δζ | (or | AZ |) corresponding to | ζ ₂ - ζι | (or | Z ₂ Zi |); this value | Δζ | (or | ΔΖ |) having to be greater than or equal to 20mV to be in accordance with the invention, and more preferably greater than or equal to 30 mV.

1.2 Performance measurement

The coagulation yield is expressed as the fraction by weight expressed in% of the mass of masterbatch m _MB relative to the mass of targeted _masterbatch m _MBc :

R (° / o) = 100 \ ^m MBj

The calculation of the coagulation yield makes it possible to directly quantify the effectiveness of coagulation.

The mass of masterbatch m _MB is obtained by weighing the masterbatch obtained at the end of the drying step of the coagulum. Weighing is a technique well known to those skilled in the art.

The targeted masterbatch mass m _MBc is arbitrarily fixed at the start of the implementation of the method of the invention. It depends on the quantity of masterbatch that one wishes to obtain.

I. 3 Measurement of the level of solid in an elastomer latex and in an aqueous dispersion of polymeric filler.

The measurement of the solid content (also called dry extract or mass fraction) of an elastomer latex or of an aqueous dispersion of a polymeric filler is carried out using a SARTORIUS brand thermobalance, model MA35 and of the protocol supplied by the manufacturer.

Briefly, this protocol includes the following steps:

- Start the thermobalance and select the automatic measurement mode of the dry extract for a temperature of 150 ° C; the measurement conditions are adjusted according to the protocol supplied with the thermobalance;

- Open the hood of the thermobalance and introduce an aluminum cup adapted to the device;

- Carry out the tare;

- Introduce, into the cup, 3 mL of the elastomer latex to be studied or of aqueous dispersion of polymeric charge to be studied;

- Close the thermobalance cover and wait for the display of the dry extract in percentage by weight of solid when the measurement is complete.

II. DETAILED DESCRIPTION OF THE INVENTION o Method for obtaining a coagulum

The invention relates to a process for obtaining a coagulum based on at least one elastomer and at least one polymeric filler, said process comprising the following steps:

having at least one elastomer latex having a Zeta Zi potential, having at least one aqueous dispersion of a polymeric filler having a Zeta Z ₂ potential, the Zeta Z ₂ potential being of opposite sign to the Zeta Zi potential and the difference in Zeta Z ₂ and Zeta Zi potentials, in absolute value, being greater than or equal to 20 mV, bringing the elastomer latex and the aqueous dispersion of polymeric charge into contact and mixing to obtain a coagulum, recovering the coagulum.

By expression "composition based on" is meant a composition comprising the mixture and / or the in situ reaction product of the various constituents used, some of these constituents being capable of, or intended to react with each other, at least in part , during the various phases of manufacturing the composition, or during subsequent cooking, modifying the composition as it is prepared at the start. Thus, the compositions as used for the invention may be different in the non-crosslinked state and in the crosslinked state.

In the present description, unless expressly indicated otherwise, all the percentages (%) indicated are percentages by mass.

In addition, any range of values designated by the expression "between a and b" represents the range of values going from more than "a" to less than "b" (ie limits a and b excluded) while any range of values designated by the expression "from a to b" signifies the range of values going from "a" to "b" (that is to say including the strict limits a and b).

The abbreviation "pce" (usually "phr" in English for "per hundred part of rubber") means parts by weight per hundred parts by weight of elastomer (s) present in the rubber composition.

In the context of the invention, the compounds, the reagents and other components mentioned in the description, can be of fossil or biobased origin. In the latter case, they can be, partially or totally, from biomass or obtained from renewable raw materials from biomass. Are concerned in particular monomers, polymers, plasticizers, fillers, etc.

By “coagulum” within the meaning of the present invention, is meant the product obtained after coagulation, that is to say the collection of particles of colloidal solutions which weld in a single mass.

X Elastomer latex with Zeta Zy potential:

The method of the invention comprises at least one step during which there is at least one elastomer latex having a potential Ζμ

For the purposes of the present invention, the term “elastomer latex” means an elastomer which is in the form of elastomer particles dispersed in water or in an aqueous solution.

The elastomer can be a natural elastomer, such as natural rubber, or a synthetic elastomer. Preferably, the elastomer is a synthetic elastomer.

The elastomer can result from the polymerization of at least one ethylenic monomer.

By "ethylenic monomer" is meant within the meaning of the present invention, a monomer which comprises at least one ethylenic bond, that is to say at least one

- it has a carbon-carbon double bond. An ethylenic monomer can also comprise several ethylenic bonds, conjugated or not. Mention may be made, as ethylenic monomer, by way of non-exclusive examples: ethylene, α-olefin monomers such as propylene, 1-butene, isobutylene, pentene, methylpentene, 1-hexene, etc. ., diene monomers, conjugated or not, vinyl aromatic or non-aromatic monomers.

The elastomer used in the process of the invention can therefore be a homopolymer of an ethylenic monomer or else be a copolymer of at least two ethylenic monomers, that is to say result from the polymerization of at least two ethylenic monomers different from each other. The term copolymer also includes, for example, terpolymers.

Preferably, the elastomer is chosen from diene elastomers, that is to say the polymers resulting from the polymerization of at least one ethylenic monomer comprising several conjugated ethylenic bonds, and the copolymers resulting from the polymerization of at least one monomer ethylenic and a vinyl monomer, in particular the copolymers resulting from the polymerization of at least one ethylenic monomer and of a vinyl ester monomer of carboxylic acid.

By "elastomer or diene rubber" must be understood in a known manner an elastomer derived at least in part (i.e., a homopolymer or a copolymer) from diene monomers (monomers carrying two carbon-carbon double bonds, conjugated or not).

These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". In general, the term “essentially unsaturated” means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of units or units of diene origin (conjugated dienes) which is greater than 15% (% by moles); This is how diene elastomers such as butyl rubbers or copolymers of dienes and of alphaolefins of the EPDM type do not enter into the preceding definition and can be qualified in particular as “essentially saturated” diene elastomers (rate of units d weak or very weak diene origin, always less than 15%). In the category of “essentially unsaturated” diene elastomers, the expression “highly unsaturated” diene elastomer is understood in particular to mean a diene elastomer having a level of diene origin units (conjugated dienes) which is greater than 50%.

These definitions being given, the term “diene elastomer capable of being used in the context of the invention” more particularly means:

(a) any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms;

(b) any copolymer obtained by copolymerization of one or more dienes conjugated together or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms;

- 12 (c) a ternary copolymer obtained by copolymerization of ethylene, of an α-olefin having 3 to 6 carbon atoms with a non-conjugated diene monomer having of 6 to 12 carbon atoms, such as for example the elastomers obtained with starting from ethylene, from propylene with a non-conjugated diene monomer of the aforementioned type such as in particular 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene;

(d) a copolymer of isobutene and isoprene (butyl rubber), as well as the halogenated versions, in particular chlorinated or brominated, of this type of copolymer.

As conjugated dienes, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di (C1-C5 alkyl) -1,3-butadienes such as, for example, are suitable. , 3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1, 3-butadiene, an aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene. Examples of vinyl aromatic compounds are styrene, ortho-, meta-, para-methylstyrene, the commercial “vinyl-toluene” mixture, para-tertiobutylstyrene, methoxystyrenes, chlorostyrenes, vinyl mesitylene, divinylbenzene, vinylnaphthalene.

The copolymers can contain between 99% and 20% by weight of diene units and between 1% and 80% by weight of vinyl aromatic units.

The aforementioned elastomers may have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the quantities of modifying and / or randomizing agent used. The elastomers can be, for example, block, statistical, sequenced, microsequenced, and be prepared in dispersion or in solution; they can be coupled and / or starred or functionalized with a coupling and / or star-forming or functionalizing agent.

The elastomer used in the context of the invention may also be a copolymer resulting from the polymerization of at least one ethylenic monomer and a vinyl monomer. The vinyl monomer can be aromatic or non-aromatic, preferably non-aromatic. Advantageously, the vinyl monomer can be chosen from vinyl esters of carboxylic acids, in particular vinyl esters of C2-C8 carboxylic acids, preferably vinyl esters of C2-C4 carboxylic acids, even more preferably are chosen from vinyl acetate and vinyl propionate.

More preferably, the elastomer is chosen from polybutadienes, synthetic polyisoprenes, butadiene-styrene copolymers, butadiene-isoprene copolymers, butadiene-acrylonitrile copolymers, isoprene-styrene copolymers, butadiene copolymers -styrene-isoprene and copolymers of ethylene and vinyl esters of C2-C4 carboxylic acids.

- 13 The synthetic elastomer latex may consist of a synthetic elastomer already available in the form of an emulsion (for example a copolymer of butadiene and styrene SBR synthesized in emulsion or a copolymer of ethylene and vinyl acetate (EVA) synthesized in emulsion), or a synthetic elastomer synthesized in solution (for example an SBR prepared in solution or in EVA prepared in solution) which is emulsified in a mixture of organic solvent and water, generally by means of an ionic surfactant.

The latexes of elastomers used in the context of the invention and in particular the latexes of preferred elastomers can be obtained in particular by radical emulsion polymerization in aqueous phase. This technique is well known to those skilled in the art. Preferably, the latexes of elastomers used in the context of the invention and in particular the latexes of preferred elastomers, are obtained in particular by radical polymerization in emulsion in aqueous phase and in the presence of at least one ionic surfactant. Ionic surfactants such as cationic and anionic surfactants are compounds also well known to those skilled in the art. Depending on the type of surfactant used during the synthesis of the elastomer or else used to emulsify an elastomer in solution, the Zeta Zi potential of the elastomer latex may be positive or negative. We will then speak of anionic or cationic elastomer latex. For example, when an anionic surfactant is used during the synthesis of the elastomer or to emulsify an elastomer in solution, the Zeta Zi potential of the elastomer latex is strictly less than OmV and the absolute value of the potential is greater than or equal at 10 mV; elastomer latex is an anionic elastomer latex. Conversely, when a cationic surfactant is used during the synthesis of the elastomer or to emulsify an elastomer in solution, the Zeta Zi potential of the elastomer latex will be strictly greater than 0 mV and the absolute value of this potential is greater than or equal to 10 mV; the elastomer latex is a cationic elastomer latex. The absolute value limit (i.e. 10 mV) allows in particular to ensure the stability of the Zeta potential measurement carried out.

Elastomer latexes and their production methods are well known to the skilled person and are commercially available in particular from suppliers such as Arkema, Synthos, Synthomer, Celanese, etc.

Preferably, the elastomer latex has a solid content of at least 35% by weight relative to the total weight of the elastomer latex. This rate can in particular be measured according to the method described in paragraph 1.3.

V Aqueous dispersion of a polymeric filler with Zeta 2 potential

The method of the invention comprises at least one step during which there is at least one aqueous dispersion of a polymeric filler having a Z ₂ potential, the Zeta Z ₂ potential being of opposite sign to the Zeta Zi potential. and the

- 14 difference of Zeta Z ₂ and Zeta Zi potentials, in absolute value, being greater than or equal to 20 mV, preferably being greater than or equal to 30 mV.

By “polymeric filler” is meant a filler, as commonly used in formulation (that is to say a substance added to a matrix with a view to modifying some of these properties), comprising a, in particular consisting essentially of 'one or consisting of a crosslinked polymer, and optionally functionalized. Preferably, the polymeric filler consists of a crosslinked and functionalized polymer.

By "crosslinked polymer" is meant in the sense of the present invention, a polymer in the form of a network obtained by the establishment of bridges between the macromolecular chains of the polymer. These interconnected chains are for the most part distributed in the three dimensions of space. A crosslinked polymer forms a three-dimensional network. In practice, the formation of a polymer network is ensured by a solubility test. It can be ensured that a network of polymers has been formed by placing the network of polymers in a solvent known to dissolve non-crosslinked polymers of the same chemical nature. If the polymer swells instead of dissolving, those skilled in the art know that a network has been formed.

Since the polymer constituting the filler is crosslinked, the reinforcing filler is in the form of particles, in particular in the form of nanoparticles, that is to say in the form of particles whose main dimension is less than one μm .

By “aqueous dispersion of polymeric filler”, is understood within the meaning of the present invention, a polymeric filler being in the form of particles, in particular in the form of nanoparticles that is to say in the form of particles whose main dimension is less than one pm, said particles being dispersed in water or in an aqueous solution.

The aqueous dispersion of polymeric filler is chosen so that its Zeta Z ₂ potential is of opposite sign to the Zeta Zi potential of the elastomer latex to which the filler is to be added and that the difference in Zeta Z ₂ and Zi potentials, in absolute value, either greater than or equal to 20 mV, preferably greater than or equal to 30 mV.

Preferably, the aqueous dispersion of polymeric filler is obtained by radical emulsion polymerization in the aqueous phase. This technique is well known to those skilled in the art.

More preferably, the aqueous dispersion of polymeric filler is obtained by radical emulsion polymerization in the aqueous phase and in the presence of an ionic surfactant. Depending on the type of surfactants used, the Zeta Z ₂ potential of the polymeric charge dispersion may be positive or negative. We then speak of an aqueous dispersion of anionic polymeric charge or of an aqueous dispersion of cationic polymeric charge. For example, when an anionic surfactant is used when

Obtaining the aqueous dispersion of polymeric charge, the Zeta Z ₂ potential is strictly less than 0 mV and the absolute value of the potential is greater than or equal to 10 mV, the aqueous dispersion is an aqueous dispersion of anionic polymeric charge. Conversely, when a cationic surfactant is used when obtaining the aqueous dispersion of polymeric charge, the Zeta Z ₂ potential is strictly greater than 0 mV and the absolute value of this potential is greater than or equal to 10 mV, the aqueous dispersion is an aqueous dispersion of cationic polymeric charge. The limit of the absolute value (ie 10 mV) makes it possible in particular to ensure the stability of the Zeta potential measurement carried out.

The polymeric fillers used in the context of the present invention are known to those skilled in the art and are in particular described, as well as their method of synthesis, in documents US2004 / 0044135, EPI 149867, EP1298166,

W02006 / 069792 and W02008 / 003434.

Preferably, the polymeric filler comprises one, in particular consists of a functionalized and crosslinked vinyl polymer.

By “vinyl polymer” is meant a polymer resulting from the polymerization of at least one vinyl monomer, that is to say a monomer carrying a vinyl group (CH ₂ = CH-) or a vinylidene group (CH ₂ = C <).

More preferably, the functionalized and crosslinked vinyl polymer results from the copolymerization of at least:

- an aromatic or non-aromatic vinyl monomer M1,

a M2 monomer having a polymerizable unsaturated group and at least one functional group chosen from the group consisting of an epoxy group, a hydroxysilyl group, an alkoxysilyl group, a hydroxyl group, an amino group and a carbonyl group (in particular a carboxylic acid group ), and

- A crosslinking monomer M3 having at least two polymerizable unsaturated groups.

By "polymerizable group" is meant an atom or set of atoms forming part of a monomer capable of reacting radically to form a polymer. For example, a carbon-carbon double bond, an acrylate or methacrylate group are polymerizable unsaturated groups within the meaning of the present invention.

Preferably, the monomer M1 can be chosen from vinyl alcohols, vinyl ethers, acrylonitrile, methacrylonitrile, vinyl esters C2-C8, alkyl acrylates C1-C12, alkyl methacrylates C1- C12 and styrenic compounds (such as styrene, 2-methylstyrene, 3-methylstryrene, ethylvinylbenzene, divinylbenzene)).

Preferably, the monomer M2 can be chosen from the acrylates and methacrylates of hydroxysilyl-alkyl (Ci-C4), the acrylates and methacrylates of alkoxy (Ci-C4) silyl-alkyl (Ci-C4), glycidyl methacrylate.

Preferably, the monomer M3 can be chosen from polyac diacrylates or polyol dimethacrylates, in particular diols or triols (for example ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane), alkylene diacrylamides or alkylene dimethacrylamides (for example methylene bis-acrylamide), vinylaromatic compounds, preferably styrenic, carrying at least two vinyl groups (for example diisopropenylbenzene (DIB), divinylbenzene (DVB), trivinylbenzene (TVB))

More preferably, the functionalized and crosslinked vinyl polymer results from the copolymerization of at least:

an Ml monomer chosen from styrene and ethylvinylbenzene, an M2 monomer chosen from trimethoxysilylpropyl methacrylate (abbreviated to MTSP), trimethoxysilylpropyl acrylate (ATSP) and trimethoxysilylethylstyrene (TSES), styrylethyl-trimethoxylate glycidyl, and a monomer M3 chosen from diisopropenylbenzene, divinylbenzene and trivinylbenzene.

Preferably, the quantity of polymeric filler when it is brought into contact with the elastomer latex ranges from 20 to 50 parts by weight per hundred parts of elastomer.

Preferably, the polymeric filler is a reinforcing polymeric filler.

By "reinforcing polymeric filler" is meant a polymeric filler of synthetic origin, comprising a, in particular consisting of a functionalized and crosslinked polymer, which added to an elastomer makes it possible to improve its properties. Such a charge is capable of replacing conventional carbon blacks for tires. For the purposes of the present invention, carbon black is not considered to be a polymeric filler. Indeed, carbon blacks do not consist of a chain of monomer units which form a polymer but simply of a chain of carbon atoms. The polymer constituting the reinforcing filler is functionalized so as to be able to interact directly or indirectly with the elastomer to which it is added to improve its properties. The reinforcing properties of the polymeric filler can be measured by any technique known to those skilled in the art, in particular by measuring the dynamic properties of a composition into which the reinforcing polymeric filler has been introduced and by plotting the modulus / elongation curves. The dynamic properties are measured according to standard NF T-46-002 of September 1988.

- 17 • f Step for bringing into contact and mixing the elastomer latex and the aqueous dispersion of polymeric filler

Bringing the elastomer latex into contact with the aqueous dispersion of polymeric filler and mixing them in particular allows spontaneous (instantaneous) coagulation of these two dispersions (that is to say the elastomer latex and the aqueous dispersion of polymeric charge) and obtaining a coagulum.

To bring these two dispersions into contact and mix, it is possible to use any type of device allowing effective mixing of two products in the liquid phase. So we can use a static mixer such as those sold by the companies Noritake Co., Limited, TAH in the USA, KOFLO in the USA, or TOKUSHU KIKA KOGYO Co., Ltd. or a mixer producing a high shear such as mixers marketed by TOKUSHU KIKA KOGYO Co., Ltd., or by the company PUC in Germany, by the company CAVITRON in Germany or by the company SILVERSON in the United Kingdom.

During this phase, an elastomer-based polymeric coagulum is formed either as a single solid element in the solution or as several separate solid elements.

The volume of aqueous dispersion of the polymeric charge depends on the rate of polymeric charge targeted for the coagulum to be produced, on the volume of the elastomer latex and on their respective concentration. Thus, the volume will be adapted accordingly, by a person skilled in the art and according to the different applications targeted.

Advantageously, to obtain a coagulation yield greater than or equal to 80% by mass, it is preferable to choose an elastomer latex having a solid content of at least 35% by weight relative to the total weight of the elastomer latex (total weight of the elastomer latex = weight of aqueous solution + weight of solid) and the quantity of polymeric filler ranges from 20 to 50 phr.

Preferably, the step of bringing the elastomer latex into contact with the aqueous dispersion of polymeric filler and their mixture does not require the addition of a coagulation agent. It is the choice of Zeta potentials of opposite algebraic sign of these dispersions as well as the difference of Zeta potentials, in absolute value (which is greater than or equal to 20 mV (preferably greater than or equal to 30 mV)), which allows d 'have instant coagulation of these dispersions. By avoiding the use of coagulation agents, the process according to the invention can be carried out with less toxic compounds. Furthermore, the production of reaction by-products is limited (little or no release of VOC compounds), and the number of steps enabling the masterbatch to be obtained is reduced. The process according to the invention is therefore advantageously simpler, faster, cheaper and less dangerous for users.

- 18 “By not requiring the addition of a coagulation agent” or “free of the addition of coagulation”, it is understood within the meaning of the present invention that coagulation is carried out without a coagulation agent or else in the presence of an amount of coagulation agent less than 0.5 phr. By "coagulation agent" is meant in the sense of the present invention, any additive capable of destabilizing an emulsion or a dispersion comprising dispersed particles to coagulate these particles. Coagulation agents are well known to those skilled in the art and can in particular be inorganic salts such as calcium chloride, magnesium chloride, aluminum chloride, aluminum nitrate, aluminum sulfate, sodium sulfate, or acids such as nitric acid, hydrochloric acid, phosphoric acids and sulfuric acids. The coagulation agent can also be an organic liquid such as an alcohol such as methanol or Tisopropanol, acetone.

Preferably, the method of the invention can be implemented, for example, with an anionic elastomer latex, that is to say having a negative Zeta Zi potential, and an aqueous dispersion of cationic polymeric charge, it that is to say having a positive Zeta Z ₂ potential, or else with a cationic elastomer latex, that is to say having a positive Zeta Zi potential, and an aqueous dispersion of anionic polymeric charge, that is to say ie having a negative Zeta Z ₂ potential provided that the difference of these Zeta potentials, ΔΖ, has an absolute value | ΔΖ | corresponding to | Z ₂ - Zi | ; this value | ΔΖ | must be greater than or equal to 20mV, and more preferably greater than or equal to 30 mV. Preferably, the elastomer latex is an anionic elastomer latex and the aqueous dispersion of polymeric charge is an aqueous dispersion of cationic polymeric charge provided that the difference of the Zeta potentials of the elastomer latex and of the aqueous dispersion of polymeric charge, ΔΖ, has an absolute value | ΔΖ | greater than or equal to 20 mV, and more preferably greater than or equal to 30 mV.

X Recovery of the coagulum formed

The solid or solids are recovered, for example, by filtration or by centrifugation or by any other liquid / solid separation technique well known to those skilled in the art.

For example, the filtering operation which can be carried out using a filter screen.

When the coagulum is in the form of numerous and small solid elements, it is preferably possible to carry out a centrifugation operation in addition to the first separation step, for example in addition to a filtration step.

- 19V Additives

The elastomer latex and the aqueous dispersion of polymeric filler may also contain all or part of the usual additives usually used in elastomer compositions in particular intended for the manufacture of tires, in particular treads, provided that these additives do not do not modify the Zeta potential of dispersions. These additives can be, for example, plasticizers or extension oils, whether the latter are of aromatic or non-aromatic nature, pigments, protective agents such as anti-ozone waxes, chemical anti-ozone, anti-oxidants, anti-fatigue agents, crosslinking agents other than those mentioned above, reinforcing resins or plasticizing agents, acceptors (for example phenolic novolak resin) or methylene donors (for example HMT (hexamethylenetetramine) or H3M (hexamethoxymethylmelamine )) as described for example in application W002 / 10269, a crosslinking system based either on sulfur or on sulfur and / or peroxide and or bismaleimide donors, vulcanization accelerators, vulcanization activators.

Preferably, these dispersions (the elastomer latex and the aqueous dispersion of polymeric filler) comprise, as preferred non-aromatic or very weakly aromatic plasticizing agent, at least one compound chosen from the group consisting of naphthenic, paraffinic oils, MES oils, TDAE oils, glycerol esters (in particular trioleates), plasticizing hydrocarbon resins having a high glass transition temperature Tg preferably greater than 30 ° C, and mixtures of such compounds.

These additives can also be incorporated after the formation of the coagulum.

It is also possible to add to the medium, after coagulation, other types of fillers different from those described above such as, for example, carbon blacks or else inorganic reinforcing fillers, such as silica with agents of coupling, coupling activators, recovery agents.

o Coagulum

The invention also relates to a coagulum comprising at least one elastomer and at least one polymeric filler, in particular a reinforcing filler, obtained according to the process defined above.

-20o Masterbatch

Another object of the present invention relates to a process for obtaining a masterbatch comprising at least one elastomer and at least one polymeric filler, in particular a reinforcing filler, said process comprising the following steps:

have a coagulum as defined above or obtained according to the method defined above;

dry the coagulum to obtain a masterbatch.

The drying step can be carried out by any drying technique well known to those skilled in the art. It can for example be carried out by placing the coagulum in an oven. After drying, the masterbatch obtained is in the form of “crumbs” (crumbs) of composite material comprising the elastomer and the polymeric filler, in particular reinforcing filler, dispersed in the elastomer matrix.

The process for obtaining a masterbatch according to the invention can be carried out continuously, as well as discontinuously ("batch" process).

Another object of the present invention relates to a masterbatch comprising at least one dried and defined coagulum previously or a masterbatch obtained by the above process.

Preferably, the additives mentioned above can also be added before or after the coagulum drying step.

Preferably, the masterbatch has a rate of polymeric charge, in particular reinforcing, ranging from 20 to 50 phr.

o Rubber composition

Advantageously, the masterbatches thus produced are capable of being used in rubber compositions, in particular intended for the manufacture of tires.

Another object of the invention thus relates to a rubber composition based on at least one dried coagulum as defined above or on at least one mixture as master defined above.

The rubber compositions according to the invention may also comprise all or part of the usual additives usually used in elastomer compositions in particular intended for the manufacture of tires, in particular treads. These usual additives are those which can be added to the coagulum or to the masterbatch.

The rubber compositions according to the invention can also comprise an elastomer identical or different from the elastomer which was used to obtain

-21 of the coagulum and of the masterbatch as well as another filler, in particular a reinforcing filler such as carbon black or silica.

Of course, the compositions according to the invention can be used alone or as a blend (i.e. mixture) with any other rubber composition which can be used for the manufacture of semi-finished products and tires.

It goes without saying that the invention relates to the rubber compositions described above, both in the “raw” or non-crosslinked state (ie before baking) and in the so-called “cooked” or crosslinked state, or else vulcanized (ie after vulcanization).

The compositions of the invention are well suited for the manufacture of semi-finished and finished products for tires, in particular for tires intended to equip non-motor vehicles such as bicycles, motor vehicles of the passenger type, SUVs ( Sport Utility Vehicles), two-wheelers (including motorcycles), airplanes, industrial vehicles chosen from vans, heavy goods vehicles (i.e. metro, buses, road vehicles (trucks and trailers)) , off-road vehicles, such as agricultural or civil engineering vehicles, other transport or handling vehicles.

S Manufacture of rubber compositions

The rubber compositions of the invention are produced in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first working phase or thermo-mechanical kneading (sometimes called a phase "Non-productive") at high temperature, up to a maximum temperature between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C, followed by a second phase of mechanical work (sometimes qualified as "productive" phase) at a lower temperature, typically less than 120 ° C., for example between 23 ° C. and 100 ° C., the finishing phase during which the crosslinking system is incorporated.

The first (non-productive) phase is preferably carried out in several thermomechanical stages. During a first step, the masterbatch according to the invention, optionally one or more elastomer (s), optionally one or more reinforcing filler (s) is introduced into a suitable mixer such as a conventional internal mixer. s) different from the reinforcing polymeric filler, optionally the combination of plasticizers (and optionally coupling agents and / or other ingredients with the exception of the crosslinking system), at a temperature between 20 ° C and 100 ° C and preferably between 25 ° C and 100 ° C. After a few minutes, preferably from 0.5 to 2 min and a rise in temperature to 90 ° C to 100 ° C, the other ingredients (that is to say, those which remain if all have not been put at the start) are added all at once or in parts, with the exception of the crosslinking system during mixing from 20 seconds to a few minutes. The total duration of the

-22mixing, in this non-productive phase, is preferably between 2 and 10 minutes at a temperature less than or equal to 180 ° C, and preferably less than or equal to 170 ° C.

After the mixture thus obtained has cooled, the crosslinking system is then incorporated at low temperature (typically less than 100 ° C.), generally in an external mixer such as a cylinder mixer; the whole is then mixed (productive phase) for a few minutes, for example between 5 and 15 min. A person skilled in the art knows how to choose the appropriate crosslinking system according to the elastomers used. For example, it can use a peroxide crosslinking system if the elastomer is a polymer resulting from the polymerization of ethylene and vinyl esters of C2-C4 carboxylic acids.

The final composition thus obtained is then calendered, for example in the form of a sheet or a plate, in particular for characterization in the laboratory, or else extruded, to form for example a rubber profile used for the manufacture of semi-finished products. finished in order to obtain products such as a tread. These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art.

The crosslinking (or baking) is carried out in a known manner at a temperature generally between 130 ° C and 200 ° C, under pressure, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the baking temperature. , of the crosslinking system adopted, of the crosslinking kinetics of the composition under consideration or of the size of the tire.

o Semi-finished article and Finished article

Another object of the present invention relates to a semi-finished article comprising at least one crosslinkable or crosslinked rubber composition as defined above or capable of being obtained by the process described above.

A semi-finished product is a rubber product intended for the manufacture of tires. It can be any type of rubber strip, such as in particular treads, underlayments, crown reinforcement plies (for example working plies, protective plies or hooping plies), plies carcass reinforcement, sidewall plies, bead plies, protective plies, underlayment plies, rubber block plies and other plies providing the interface between the aforementioned areas of tires. Preferably, the semi-finished article is a tread.

The invention also relates to a tire comprising at least one semi-finished article as mentioned above or comprising at least one composition as defined above.

The tire according to the invention can be intended in particular to equip non-motor vehicles such as bicycles, motor vehicles of the tourism type, SUVs (Sport Utility Vehicles), two wheels (in particular motorcycles), airplanes , industrial vehicles chosen from vans, heavy goods vehicles (i.e. the metro, buses, road vehicles (trucks and trailers)), off-road vehicles, such as agricultural or civil engineering, other transport or handling vehicles.

III- EXAMPLES OF IMPLEMENTATION OF THE INVENTION

The examples which follow make it possible to illustrate the invention, the latter cannot however be limited to these examples only.

III 1 Aqueous dispersions of a polymeric filler

Three aqueous dispersions of polymeric fillers were used to carry out the following tests:

an aqueous dispersion of a DPI polymeric filler, the polymeric filler comprising a cross-linked siloxane functionalized vinylaromatic polymer,

- an aqueous dispersion of a DP2 polymeric filler; the polymeric charge comprising a vinyl aromatic polymer functionalized with glycydyl and crosslinked,

- An aqueous dispersion of a DP3 polymeric filler, the polymeric filler comprising a cross-linked glycydylated vinyl aromatic polymer.

The preparation of the aqueous dispersion of a polymeric filler consists in synthesizing the filler chemically in the aqueous phase, in particular via a radical synthesis process in emulsion in order to obtain particles stabilized in the aqueous phase by an ionic surfactant introduced during the synthesis.

III 1.1 Preparation of the DPI aqueous dispersion

The aqueous dispersion of DPI polymeric filler is obtained by radical emulsion polymerization. This polymerization is carried out in a buffered medium at equal pH 7, with a simultaneous introduction into a styrene reactor, of MTPS (3- (trimethoxysilyl) -propyl methacrylate) and of divinylbenzene (DVB). At the end of the reaction, particles of functionalized and crosslinked vinyl aromatic polymer are obtained which are dispersed in the aqueous phase.

The polymerization reaction is carried out in a 50 liter reactor fitted with mechanical stirring. After introducing 10 L of water and sparging with nitrogen for 30 min with stirring, 240 g of surfactant (cetyltrimethylammonium chloride CTAC), 800 g of a 75 g / L buffer solution are successively introduced

-24 sodium hydrogen phosphate (54 g) and 32 g / L ammonium dihydrogen phosphate (23 g), solution previously prepared by solubilization of the salts in bubbled water and then stored under nitrogen. To this solution, slowly stirred at 150 rpm and heated to 60 ° C., are added the following quantities of monomers bubbled beforehand with nitrogen: 174 g of MTPS, 345 g of DVB at 80% by mass (the remaining 20% being ethylvinylbenzene) and 681 g of styrene.

Finally, the initiator, potassium persulfate (14.4 g) is added and the reaction medium is kept stirring (120 rpm) for 6 hours at 60 ° C. After the 6 h reaction, 24 L of a resorcinol solution (1 g / L) are added to the polymerization medium. The reaction medium is then cooled. The conversion measured by the dry extract is 100%

The functionalized and crosslinked polymer forming the particles consists of 62.5% by mass of styrene (including ethylvinylbenzene), 23% by mass of divinylbenzene and 14.5% of MTPS.

An aqueous dispersion of DPI polymeric filler is obtained, the solid content of which is approximately 4.2% by weight relative to the total weight of the aqueous dispersion.

III. 1.2 Preparation of the DP2 aqueous dispersion

The aqueous dispersion of DP2 polymeric filler is obtained by radical emulsion polymerization. This polymerization is carried out in a buffered medium at equal pH 7, with a simultaneous introduction into a styrene reactor, of GMA (glycidyl methacrylate) and of divinylbenzene (DVB). At the end of the reaction, particles of functionalized and crosslinked vinyl aromatic polymer are obtained which are dispersed in the aqueous phase.

The polymerization reaction is carried out in a 50 liter reactor fitted with mechanical stirring. After introducing 10 L of water and bubbling with nitrogen for 30 min with stirring, 240 g of surfactant (95% cetyltrimethylammonium chloride; CTAC), 800 g of a buffer solution are successively introduced. 75 g / L of sodium hydrogen phosphate (i.e. 54 g) and 32 g / L of ammonium dihydrogen phosphate (i.e. 23 g), solution previously prepared by solubilization of the salts in bubbled water and then stored under nitrogen. To this solution, slowly stirred at 150 rpm and heated to 60 ° C., are added the following quantities of monomers bubbled beforehand with nitrogen: 108 g of GMA, 375 g of DVB at 80% by mass (the remaining 20% being ethylvinylbenzene) and 717 g of styrene.

Finally, the initiator, potassium persulfate (14.4 g) is added and the reaction medium is kept stirring (120 rpm) for 6 hours at 60 ° C. After the 6 h reaction, 24 L of a resorcinol solution (1 g / L) are added to the polymerization medium. The reaction medium is then cooled. The conversion measured by the dry extract is 100%

The functionalized and crosslinked polymer forming the particles consists of 66% by mass of styrene (including ethylvinylbenzene), 25% by mass of divinylbenzene and 9% of GMA.

An aqueous dispersion of polymeric DP2 filler is obtained, the solid content of which is approximately 4.2% by weight relative to the total weight of the aqueous dispersion.

III. 1.31 ⁾ repair of the DP3 aqueous dispersion

The aqueous dispersion of DP3 polymeric filler is obtained by radical emulsion polymerization. This polymerization is carried out in a buffered medium at equal pH 7, with a simultaneous introduction into a styrene reactor, of GMA (glycidyl methacrylate) and of divinylbenzene (DVB). At the end of the reaction, particles of functionalized and crosslinked vinyl aromatic polymer are obtained which are dispersed in the aqueous phase.

The polymerization reaction is carried out in a 50 liter reactor fitted with mechanical stirring. After introducing 9.2 L of water and sparging with nitrogen for 30 min with stirring, 156 g of surfactant (sodium dodecyl sulphate, SDS), 1594 g of a 75% buffer solution are successively introduced. g / L of sodium hydrogen phosphate (i.e. 108 g) and 32 g / L of ammonium dihydrogen phosphate (i.e. 45.6 g), solution previously prepared by solubilization of the salts in bubbled water and then stored under nitrogen. To this solution, slowly stirred at 150 rpm and heated to 60 ° C., are added the following quantities of monomers bubbled beforehand with nitrogen: 108 g of GMA, 375 g of DVB at 80% by mass (the remaining 20% being ethylvinylbenzene) and 717 g of styrene.

Finally, the initiator, potassium persulfate (14.4 g) is added and the reaction medium is kept stirring (120 rpm) for 6 hours at 60 ° C. After the 6 h reaction, 24 L of a resorcinol solution (1 g / L) are added to the polymerization medium. The reaction medium is then cooled. The conversion measured by the dry extract is 100%

The functionalized and crosslinked polymer forming the particles consists of 66% by mass of styrene (including ethylvinylbenzene), 25% by mass of divinylbenzene and 9% of GMA.

An aqueous dispersion of polymeric DP3 filler is obtained, the solid content of which is approximately 4.2% by weight relative to the total weight of the aqueous dispersion.

-26III. 2 Elastomer latex

Four latexes of separate elastomers were used to carry out the following tests:

- Latex 1 is an e-SBR elastomer latex (e-SBR = styrene butadiene copolymer in emulsion) having a solid content equal to 20.6% by weight relative to the total weight of the elastomer latex, the rate of solid being measured according to the method described in paragraph 1.3. This latex is available under the name "SB Latex 1502" from the company SYNTHOS;

- Latex 2 is an e-SBR elastomer latex (SBR = styrene butadiene copolymer) having a solid content equal to 50.4% by weight relative to the total weight of the elastomer latex, the solid content being measured according to the method described in paragraph 1.3. This latex is available under the name "Litex SX 1024" from the company SYNTHOMER;

- Latex 3 is an e-EVA elastomer latex (e-EVA = copolymer of ethylene and vinyl acetate in emulsion) having a solid content equal to 48.8% by weight relative to the total weight of the latex, the solid content being measured according to the method described in paragraph 1.3. It is available under the name Vinamul 3301 from CELANESE;

- Latex 4 is an e-EVA elastomer latex (EVA = copolymer of ethylene and vinyl acetate) having a solid content equal to 60.8% by weight relative to the total weight of the elastomer latex, the rate of solid being measured according to the method described in paragraph 1.3. It is available under the name of Mowilith LDM 1365 from the company CELANESE.

III. 3 Zeta potential of elastomer latex and aqueous dispersions of polymeric charge

Table 1 indicates for the aqueous dispersions of polymeric charges, the Zeta Z ₂ potential values obtained in accordance with the method described in paragraph 1.1 and according to the measurement protocol described in the user manual of the ZetaSizer Nano-ZS from Malvern Instruments. .

Table 1

Aqueous dispersion DP 1 DP 2 DP3 Zeta Z ₂ potential (mV) + 41 ± 2 + 38 + 2 -41 + 2

Table 2 indicates, for the aforementioned elastomer latexes, the Zeta potential values obtained in accordance with the method described in paragraph 1.1 and following

-27the measurement protocol described in the user manual of the ZetaSizer Nano-ZS from Malvem Instruments.

To measure the zeta potential Z of Latex 1 and Latex 2 that of a xlOO dilution in NaCl solution at 10 ^-3 M was performed as described in subsection 1.1

To measure zeta potential Z | 3 Latex and the Latex 4 a x500 dilution in NaCl 10 ^'3 million was needed instead of xlOO dilution specified in paragraph 1.1.

Table 2

Elastomer latex Latex 1 Latex 2 Latex 3 Latex 4 Zeta potential Zi (mV) -42 ± 2 -40 ± 2 -42 ± 2 -25 ± 2

III 4 Obtaining coagulums and masterbatches

The masterbatches are produced by “batch” contacting. A defined quantity of aqueous dispersion of polymeric filler to be tested prepared according to the teaching of paragraph III. 1.1, is introduced into a defined quantity of elastomer latex prepared according to the teaching of paragraph and III. 1.2, according to the following protocol:

- We weigh a defined quantity of elastomer latex to be tested in a 200mL beaker,

- a magnetic bar is introduced into the beaker and the elastomer latex is stirred with magnetic stirring, a defined amount of aqueous dispersion of polymeric reinforcing filler to be tested is weighed out, the aqueous dispersion of polymeric filler is introduced into once in the beaker containing the elastomer latex with magnetic stirring.

The masses of elastomer latex and of aqueous dispersion of polymeric filler to be weighed are defined directly by the mass of targeted masterbatch (dry masterbatch), the rate of targeted filler in the masterbatch and the respective mass fractions of the latex and slurry. In this example, the target masterbatch mass is 20 g.

The masses of elastomer latex nt _z and aqueous dispersion of polymeric filler m _s to be weighed are defined from the following expressions:

with FM _t the mass fraction of the latex expressed in%; FM _S the mass fraction of the aqueous dispersion of polymeric charge expressed in%; TC _c the target charge rate expressed in phr (part by mass of charge per hundred parts by mass of elastomer) and m _MBc the mass of targeted masterbatch.

The target masterbatch mass m _MBc is here set at 20g.

For each rate of polymeric reinforcing filler targeted in the masterbatches, tables 3, 4 and 5 are shown below, the masses of elastomer latex and of aqueous dispersion of polymeric filler weighed.

During the contacting and mixing phase of the two dispersions, that is to say the elastomer latex and the aqueous dispersion of polymeric filler, a coagulum of elastomer and of polymeric filler is formed in the form of '' only one solid element in the solution.

The mixture is maintained for a few minutes with magnetic stirring before recovery of the coagulum formed.

In order to have identical conditions of the operating mode for the different tests, the coagulum formed or the solids formed (commonly called “crumbs” in English) are centrifuged, including in cases where the visual appearance of the coagulum allowed to consider a filtering operation.

According to a preferred embodiment, the coagulum is separated from the effluents by centrifugation after transfer to a 250 ml Nalgene® bottle using a Sigma 4K15 bucket centrifuge sold by the company Sigma. Centrifugation is carried out at a temperature of 20 ° C. and at a speed of 9000 rpm for 15 min.

A masterbatch is obtained by drying the coagulum in an oven at 60 ° C under 200 mbar pressure up to a humidity level of less than 1% by mass.

The coagulation yield is then measured according to the method described in paragraph 1.2.

The measurement of the coagulation yield makes it possible to directly quantify the effectiveness of the process according to the invention.

III. 4 Tests

The following masterbatches are produced according to the above protocol, for each of the four elastomer latexes mentioned above:

-29- masterbatches with a DPI charge dispersion with charge rates 25 pce, 35 pce, and 45 pce,

- masterbatches with a DP2 charge dispersion with charge rates 25 pce, 35 pce, and 45 pce,

- masterbatches with a DP3 charge dispersion with charge rates of 15 pce, 25 pce, and 35 pce,

III.4.1 Coagulum and masterbatches according to the invention

The masterbatches MB1, MB2, MB3 and MB4, in accordance with the invention, respectively correspond respectively to masterbatches produced according to paragraphs III.4, from the aqueous dispersion of polymeric filler DPI and from Latex 1, Latex 2, Latex 3 and Latex 4, with the following differences:

• MB1 ₂ 5 is a masterbatch produced with Latex 1 and with the aqueous dispersion DPI at a charge rate of 25 pce, • MB1 ₃₅ is identical to MB 125 but with a charge rate of 35 pce, • MBI45 is identical to MBI25 but with a targeted loading rate of 45 pce, • MB2 ₂ 5 is a masterbatch produced with Latex 2 and with the aqueous dispersion DPI at a loading rate of 25 pce, • MB2 ₃₅ is identical to MB2 ₂ 5 but with a charge rate of 35 pce, • MB2 ₄₅ is identical to MB2 ₂ 5 but with a targeted charge rate of 45 pce, • MB3 ₂ 5 is a masterbatch made with Latex 3 and with the aqueous dispersion DPI at a load rate of 25 pce, • MB3 ₃₅ is identical to MB3 ₂ 5 but with a load rate of 35 pce, • MB3 ₄₅ is identical to MB3 ₂ 5 but with a load rate of 45 pce, • MB4 ₂ 5 is a masterbatch made with Latex 4 and with the aqueous dispersion DPI at a loading rate of 25 phr, • MB4 ₃₅ is identical to MB4 ₂ 5 but with a load rate of 35 pce, • MB4 ₄₅ is identical to MB4 ₂ 5 but with a load rate of 45 pce.

Table 6 presents for these previous masterbatches the coagulation yields obtained (as also described above).

In the same way, the masterbatches MB5, MB6, MB7 and MB8, in accordance with the invention, all correspond respectively to masterbatches produced according to paragraphs III.4, from the aqueous dispersion of polymeric charge DP2 and Latex 1, Latex 2, Latex 3 and Latex 4, with the following differences:

-30 • MB5 ₂ 5 is a masterbatch produced with Latex 1 and with the aqueous dispersion DP2 at a charge rate of 25 pce, • MB5 ₃₅ is identical to MB5 ₂₅ but with a charge rate of 35 pce, • MB5 ₄₅ is identical to MB5 ₂₅ but with a charge rate of 45 pce, • MB6 ₂₅ is a masterbatch produced with Latex 2 and with the aqueous dispersion DP2 at a charge rate of 25 pce, • MB6 ₃₅ is identical to MB6 ₂₅ but with a charge rate of 35 phr, • MB6 ₄₅ is identical to MB6 ₂₅ but with a charge rate of 45 phr, • MB7 ₂₅ is a masterbatch made with Latex 3 and with the aqueous dispersion DP2 at a loading rate 25 pce, • MB7 ₃₅ is identical to MB7 ₂₅ but with a loading rate of 35 pce, • MB7 ₄₅ is identical to MB7 ₂₅ but with a loading rate of 45 pce, • MB8 ₂₅ is a masterbatch made with Latex 4 and with the aqueous dispersion of polymeric reinforcing filler DP2 at a filler rate 25 pce, • MB8 ₃ 5 is ideal tick at MB8 ₂₅ but with a load rate of 35 pce, • MB8 ₄₅ is identical to MB8 ₂₅ but with a load rate of 45 pce.

Table 7 presents for these preceding masterbatches the coagulation yields obtained (as also described above).

III.4.2 Coagulum and masterbatches not in accordance with the invention

The masterbatches MB9, MB10, MB11 and MB12, not in accordance with the invention, all correspond respectively to masterbatches produced according to paragraphs III.4, from the aqueous dispersion of polymeric filler DP3 and from Latex 1, Latex 2, Latex 3 and Latex 4, with the following differences:

• MB9i5 is a masterbatch made with Latex 1 and with the aqueous dispersion DP3 at a loading rate of 15 pce, • MB9 ₂₅ is identical to MB9 _i5 but with a loading rate of 25 pce, • MB9 ₃₅ is identical to MB9 _i5 but with a target loading rate of 35 pce, • MBIO15 is a masterbatch produced with Latex 2 and with the aqueous dispersion DP3 at a loading rate of 15 pce, • MB10 ₂₅ is identical to MBIO15 but with a rate load of 25 pce, • MB10 ₃₅ is identical to MBIO15 but with a targeted charge rate of 35 pce, • MB 1115 is a masterbatch produced with Latex 3 and with the aqueous dispersion DP3 at a charge rate of 15 pce ,

-31 • MB 11 ₂ 5 is identical to MB 11 _i5 but with a load rate of 25 pce, • MB11 ₃₅ is identical to MB1 li ₅ but with a targeted load rate of 35 pce, •

• MB12i5 is a masterbatch made with Latex 4 and with the aqueous dispersion DP3 at a loading rate of 15 pce, • MB12 ₂ 5 is identical to MB12i ₅ but with a loading rate of 25 pce, • MB12 ₃₅ is identical to MB12i ₅ but with a targeted load rate of 35 pce,

Table 8 presents for these previous masterbatches the coagulation yields obtained (as also described above).

Table 3

Masterbatch MB1 _î5 MB1 ₃₅ MB145 MB2 ₂₅ MB2 ₃₅ MB2 ₄₅ MB3 ₂₅ MBfe MB3 ₄₅ MB4 ₂₅ MB4 ₃₅ MB4 ₄₅ Charge rate in the masterbatch in pc 25 35 45 25 35 45 25 35 45 25 35 45 Weighings in g DPI 94.3 122 146 94.3 122 146 94.3 122 146 94.3 122 146 Latex 1 77.7 71.9 67 () () 0 () 0 0 () () 0 Latex 2 0 () 0 31.7 29.4 27.4 () 0 0 () () 0 Latex 3 0 () 0 () () 0 32.8 30.4 , 3 () () 0 Latex 4 0 () 0 () () 0 () 0 0 26.3 24.4 22.7 | AZ || Z ₂ -Zi | 83 81 83 66

Table 4

Masterbatch MB5 _î5 MB5 ₃ ; MB5 _4S MB6 ₂₅ MBfe MB6 ₄₅ MB7 ₂₅ MB7 ₃₅ MB7 ₄₅ MB8 ₂₅ MB8 ₃₅ MB845 Load rate in masterbatch in pce 25 35 45 25 35 45 25 35 45 25 35 45 Weighings in g DP2 97.6 126 151 97.6 126 151 97.6 126 151 97.6 126 151 Latex 1 77.7 71.9 67 () () 0 () 0 0 () () 0 Latex 2 0 () 0 31.7 29.4 27.4 () 0 0 () () 0 Latex 3 0 () 0 () () 0 32.8 30.4 28.3 () () 0 Latex 4 0 () 0 () () 0 () 0 0 26.3 24.4 22.7 | AZ || Z ₂ -Zi | 80 78 80 63

Table 5

Mixed- master MB9 ₁₅ MB9 ₂₅ MB9 ₃₅ MB10.5 MB10 _2S MB10, MB11 _b MB11 ₂₅ MBlljs MB12 ₁₅ MB12 ₂₅ MB12 ₃₅ Charge rate in the masterbatch in pc 15 25 35 15 25 35 15 25 35 15 25 35 Weighings in g DP3 62.1 95.2 123.5 62.1 95.2 123.5 62.1 95.2 123.5 62.1 95.2 123.5 Latex 1 84.4 77.7 71.9 () 0 () () 0 0 () () () Latex 2 () () 0 34.5 31.7 29.4 () 0 0 () () () Latex 3 () () 0 () 0 () 35.6 32.8 30.4 () () () Latex 4 () () 0 () 0 () () 0 0 28.6 26.3 24.4

Table 6

Masterbatch MB125 MBbs MB145 MB2 _î5 MB2 ₃₅ MB2 ₄₅ MB3 _î5 MB3j ₅ MB3 ₄₅ MB4 ₂₅ MB4 ₃₅ MB4 ₄₅ Yield of coagulation (%) 75 69 70 91 100 91 100 100 84 100 100 84

Table 7

Masterbatch MB5 ₂₅ MB5 _3S MB5 _4S MB615 MBfe MB6 ₄₅ MB7 _î5 MB7 ₃₅ MB7 ₄₅ MB8 ₂₅ MB835 MB8 ₄₅ Yield of coagulation (%) 83 83 79 100 100 85 100 100 90 100 100 83

Table S

Masterbatch MB9 _1S MB9 _{! 5} MB9 ₃₅ MB10 ₁₅ MB10 ₂₅ MBW35 MB11 _1S MB11 _{25 MB11 î5} MB12 ₁₅ MB12 _K MB12 ₃₅ Yield of coagulation (%) 0 0 0 0 0 0 0 0 0 0 0 0

It can be seen that whatever the chemical nature of the elastomer, there is no coagulation between an anionic elastomer latex and an aqueous dispersion of anionic polymeric charge, that is to say between a latex d elastomer having a Zeta potential of the same algebraic sign as the Zeta potential of an aqueous dispersion of a polymeric filler. The coagulation yield is zero (see table 8).

In accordance with the invention, it can be seen that the latexes of elastomers having a Zeta potential of algebraic sign opposite to the Zeta potential of the aqueous dispersion of polymeric charge allow, whatever the chemical nature of the elastomer or the chemical nature of the polymer reinforcing filler, to obtain a coagulum or a masterbatch without the addition of coagulation agent.

Advantageously, when the level of polymeric reinforcing filler ranges from 20 to 50 phr and the solid level of the elastomer latex is at least 30% by weight relative to the total weight of the elastomer latex, a coagulum is obtained. and a masterbatch with a yield greater than 80%.

Claims (20)

1. Process for obtaining a coagulum based on at least one elastomer and at least one polymeric filler, said process comprising the following steps: have at least one elastomer latex having a Zeta Zi potential, have at least one aqueous dispersion of a polymeric filler having a Zeta Z ₂ potential, the Zeta Z ₂ potential being of opposite sign to the Zeta Zi potential and the difference in potentials Zeta Z ₂ and Zeta Zi, in absolute value, being greater than or equal to 20 mV, bringing the elastomer latex and the aqueous dispersion of polymeric charge into contact and mixing to obtain a coagulum, recovering the coagulum. 2. Method according to claim 1, in which the elastomer is a synthetic elastomer. 3. Method according to claim 2, wherein the synthetic elastomer results from the polymerization of at least one ethylenic monomer. 4. Method according to claim 3, wherein the synthetic elastomer is chosen from diene elastomers and copolymers resulting from the polymerization of at least one ethylenic monomer and one monomer of vinyl esters of carboxylic acids. 5. Method according to claim 4, in which the synthetic elastomer is chosen from polybutadienes, synthetic polyisoprenes, butadienestyrene copolymers, butadiene-isoprene copolymers, butadiene-acrylonitrile copolymers, isoprene-styrene copolymers and butadienestyrene-isoprene copolymers, ethylene and vinyl ester copolymers of C2-C4 carboxylic acids. 6. Method according to any one of claims 2 to 5, in which the elastomer latex is obtained by radical polymerization in emulsion in aqueous phase, preferably is obtained by radical polymerization in emulsion in aqueous phase and in the presence of a ionic surfactant. 7. Method according to one of claims 2 to 5, wherein the elastomer latex is obtained by emulsification in the aqueous phase of a synthetic elastomer. -388. Process according to any one of Claims 1 to 7, in which the elastomer latex has a solid content of at least 35% by weight relative to the total weight of said elastomer latex. 9. Method according to any one of claims 1 to 8, in which the aqueous dispersion of polymeric filler is obtained by radical polymerization in emulsion in aqueous phase, preferably is obtained by radical polymerization in emulsion in aqueous phase and in the presence of an ionic surfactant. 10. Method according to one of claims 1 to 9, wherein the polymeric filler comprises a functionalized and crosslinked vinyl polymer. 11. The method of claim 10, wherein the functionalized and crosslinked vinyl polymer results from the copolymerization of at least: - an aromatic or non-aromatic vinyl monomer M1, a M2 monomer having a polymerizable unsaturated group and at least one functional group chosen from the group consisting of an epoxy group, a hydroxysilyl group, an alkoxysilyl group, a hydroxyl group, an amino group and a group a carbonyl group, and - A crosslinking monomer M3 having at least two polymerizable unsaturated groups. 12. The method of claim 11, wherein the monomer Ml is chosen from styrene and ethylvinylbenzene, the monomer M2 is chosen from trimethoxysilylpropyl methacrylate (abbreviated MTSP), trimethoxysilylpropyl acrylate (ATSP) and trimethoxysilylethylstyrene (TSES), styrylethyl-trimethoxysilane and glycidyl methacrylate, and the monomer M3 is chosen from diisopropenylbenzene, divinylbenzene and trivinylbenzene. 13. Method according to any one of claims 1 to 12, in which the quantity of polymeric filler when the elastomer latex is brought into contact with the aqueous dispersion of polymeric filler ranges from 20 to 50 parts by weight per cent parts of elastomer. 14. Method according to any one of claims 1 to 13, wherein the polymeric filler is a reinforcing polymeric filler. 15. Coagulum comprising at least one elastomer and at least one polymeric filler obtained according to the process defined in any one of claims 1 to 14. -3916. Process for obtaining a masterbatch comprising at least one elastomer and at least one polymeric filler, said process comprising the following steps: - have a coagulum defined according to claim 15 or obtained according to the process defined according to one of claims 1 to 14; 5 - dry the coagulum to obtain a masterbatch. 17. Masterbatch comprising at least one dried coagulum and defined according to claim 15. 10 18. Masterbatch according to claim 17, in which the rate of polymeric charge ranges from 20 to 50 phr. 19. A rubber composition based on at least one coagulum defined according to claim 15 or based on at least one masterbatch defined according to claim 15 17 or 18. 20. Semi-finished or finished article comprising at least one composition defined according to claim 19. 20 21. A tread comprising at least one composition defined according to claim 19. 22. A tire comprising at least one composition defined according to claim 19.