EP3870625A1

EP3870625A1 - Continuous preparation of polyurethanes or polyureas

Info

Publication number: EP3870625A1
Application number: EP19795606.3A
Authority: EP
Inventors: Benoît MAGNY; Yves MATTER; Jean-Marc Suau
Original assignee: Coatex SAS
Current assignee: Coatex SAS
Priority date: 2018-10-26
Filing date: 2019-10-15
Publication date: 2021-09-01
Also published as: MX2021002490A; FR3087774A1; WO2020084200A1; US20210269580A1; FR3087774B1; KR20210082192A; CN112805314A

Abstract

The invention relates to the field of associative thickeners, and more particularly to associative thickeners of the HEUR type, used in aqueous formulations. In particular, the invention relates to a method for the continuous preparation of HEUR-type associative thickeners by reactive extrusion. These products are intended to be used in aqueous formulations.

Description

Continuous preparation of polyurethanes or polyvureas

Description

The invention relates to the field of associative thickeners, and more particularly associative thickeners of the HEUR type, used in aqueous formulations. The invention relates, in particular, to a process making it possible to prepare in coiitinu by reactive extrusion associative thickeners of the HEUR type. These products are intended to be used in aqueous formulations.

Among the thickeners, a distinction is made between associative thickeners which are generally water-soluble polymers comprising insoluble hydrophobic groups. Such macromolecules have an associative nature: once introduced into water, the hydrophobic groups are capable of assembling in the form of micellar aggregates. These aggregates are linked together by the hydrophilic parts of the polymers. There is then a three-dimensional network which causes the viscosity of the medium to increase.

Among these associative thickeners, there is the class of associative thickeners of the HEUR type. They designate copolymers resulting from the synthesis between a compound of the polyalkylene glycol type, a polyisocyanate, and an associative monomer of the alkyl or aryl or ary alkyl type comprising a hydrophobic terminal group. These structures are notably known for developing high Brookfield viscosities at different shear gradients.

Among the HEUR thickeners, the Hydrophobically modified Ethylene oxide, Hydrophobically modified Ethylene oxide VRethane according to the appropriate acronym, are known, as well as the Hydrophobically modified Ethylene oxide Urea, Hydrophobically modified Ethylene oxide URea according to l English acronym appropriate. Also known are combinations of hydrophobically modified Ethylene Oxide and Hydrophobically modified Urea Ethylene Oxide.

Within compositions also comprising a binder compound of latex type, HEUR polymers generally make it possible to develop interactions with the particles of these binder compounds. Such interactions then generally make it possible to increase the thickening effect. The compositions comprising a thickening polymer are usually prepared by prior synthesis of the thickening polymer by a batch process, called the batch process.

EP 0 905 157 relates to thickening compositions useful for controlling the viscosity of transparent aqueous systems such as paints and coatings based on varnishes for the automotive industry. Document WO 2011-030197 discloses associative thickening polyurethanes made from polyalkylene glÿcdl, polyisocyanates and optionally oxyethylated cardanol. Document EP 2 361 939 relates to a thickening agent based on an aqueous preparation of nonionic, water-dispersible or water-soluble polyurethanes. Document EP 2 444 432 discloses a composition comprising a hydrophobically modified oxide-alkylene polyurethane, the molecular weight of which is from 50,000 to about 150,000 Daltons.

In the context of the invention, a method of preparing a thickening composition is sought, comprising a hydrophilic polymer, advantageously water-soluble, which is flexible and reproducible. It is also sought to improve the thickening efficiency of the thickening composition. The invention proposes to prepare the hydrophilic polymer continuously by reactive extrusion.

Preferably, the hydrophilic polymer is a water-soluble polymer. Within the meaning of the present invention, the term “water-soluble polymer” means a polymer which is completely miscible with water, in all proportions, at a temperature above the melting point of this polymer.

The subject of the invention is therefore a method of preparing a thickening composition comprising:

at. the preparation of a hydrophilic polymer (P) continuously by reactive extrusion,

(A) of at least one water-soluble polyalkylene glycol (A) chosen from a polyethylene glycol, a polyethylene glycol - polypropylene glycol copolymer containing at most 40% by weight of polypropylene glycol, a polyethylene glycol - polybutylene glycol copolymer containing at most 20% by weight of polybutylene glycol, and combinations thereof; (B) of at least one product (B) comprising at least one associative group and at least one isocyanate function, ^' chosen from:

• a compound (B1) of formula (I):

R- N = C = 0

(I)

in which R represents a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon group, comprising from 6 to 40 carbon atoms,

• a combination of a di-isocyanate (B3) and a compound (B 2) of formula (P):

R '- (OE) _n - (OP) _m - (OB) _p -X

(P)

in which :

o R 'represents a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon group, comprising from 6 to 40 carbon atoms, o (OE) represents an ethoxylene group, o (OP) represents a propoxylene group, o (OB) represents a butoxylene group, we represent a real number between 0 and _/ 150, om represents a real number between 0 and 150, op represents a real number between 0 and 150, where the sum of n + m + p represents a real number between 0 and 150,

o X represents a chemical group carrying a labile hydrogen capable of reacting with an isocyanate function,

• the product resulting from the prior condensation of a di-isocyanate (B3) and a compound (B2) of formula (II),

• a combination of a di-isocyanate (B3) and a compound (B1) of formula (I),

• and their combinations; b. mixing the hydrophilic polymer (P) in at least one solvent.

Thus, according to the invention, a hydrophilic polymer (P) is prepared by reaction of the compounds (A), (B) and optionally of a crosslinking compound (C), according to a continuous process of reactive extrusion.

COMPOUND (Al

Compound (A) is a water-soluble polyalkylene glycol.

The polyalkylene glycol is chosen from a polyethylene glycol, a polyethylene glycol - polypropylene glycol copolymer containing at most 40% by weight of polypropylene glycol, a polyethylene glycol - polybutylene glycol copolymer containing at most 20% by weight of polybutylene glycol, and their combinations.

The polypropylene glycol percentages are expressed by weight relative to the total weight of the polyethylene glycol - polypropylene glycol copolymer. Similarly, the percentages of polybutylene glycol are expressed by weight relative to the total weight of the polyethylene glycol - polybutylene glycol copolymer.

So that the polyethylene glycol - polypropylene glycol copolymer retains its water-soluble character, its polypropylene glycol content is less than 40% by weight, advantageously less than 35% by weight.

So that the polyethylene glycol - polybutylene glycol copolymer retains its water-soluble character, its polybutylene glycol content is less than 20% by weight, advantageously less than 15% by weight.

Compound (A) is advantageously a polyalkylene glycol having a molar mass by weight (Mw) ranging from 1,000 to 40,000 g / mol, preferably from 3,000 to 20,000 g / mol, more preferably from 4,000 to 15,000 g / mol.

According to the invention, the polylakylene glycol is preferably polyethylene glycol, preferably a polyethylene glycol of molar mass (Mw) by weight of between 2,000 g / mole and 20,000 g / mole, preferably between 8,000 g / mole and 15,000 g / mqlë. According to the invention, the molar mass of compound (A) is calculated from the hydroxyl number determined according to DIN standard 53240-1, now DIN EN ISO 4629-1 standard, of December 2016 by applying the formula: (56,100 x functionality in OH groups) / hydroxyl number. PRODUCT (B)

According to the invention, the product (B) is a compound or a combination of compounds making it possible to provide both an isocyanate function and an associative group. _; Thus, the expression “product comprising an associative group and at least one isocyanate function” describes a compound or a combination of compounds making it possible to provide at least one isocyanate function and one associative group. Indeed, the same compound can carry both an isocyanate function and an associative group. However, it is also possible to envisage a combination of several compounds with at least one compound carrying at least one isocyanate function and at least one other compound carrying an associative group.

By associative group is meant, within the meaning of the present invention, in particular a group of formula R or R ’according to the invention.

According to the invention, the product (B) is chosen from:

• a compound (B 1) of formula (I),

• a combination of a compound (B2) of formula (P) and a di-isocyanate (B3),

• the product resulting from the prior condensation of a di-isocyanate (B3): and of a compound (B2) of formula (II),

• a combination of a compound (B 1) of formula (I) and a di-isocyanate (B3),

• and their combinations.

According to the invention, the compound (B1) is a compound of formula (I):

R-N = C = 0

(I)

in which R represents a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon group, comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms.

According to the invention, the hydrocarbon group R advantageously represents an alkyl or alkenyl group, linear, branched or cyclic, advantageously linear or branched, comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms. According to the invention, the hydrocarbon group R can also represent an aromatic group comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms.

Also preferably according to the invention, the compound of formula (I) is a compound chosen from:

^• aromatic monoisocyanate compounds, in particular phenyl isocyanate, diphenylmethane monoisocyanate, 2-phenylethyl isocyanate, 4-tolyl isocyanate, 2-tolyl isocyanate, 2,5-dimethylphenyl isocyanate, 3,4-dimethylphenyl isocyanate, 2,3-dimethylphenyl isocyanate, 4 -isocyanato-4'-methyldiphenylmethane;

^• polyfunctional aromatic monoisocyanate compounds, in particular 2-methoxy-4-nitrophenyl isocyanate, polymethylene polyphenyl isocyanate;

^• alkyl-monoisocyanate compounds include hexyl isocyanate, heptyl isocyanate, octyl isocyanate, n-nonyl-isocyanate, decyl isocyanate, undecyl isoeyanate, dodecyl isocyanate, tridecyl isocyanate, tetradecyl isocyanate, cetyl-isocyanate, 2-ethyl-hexyl-isocyanate, n-octyl-isocyanate, isononyl-isocyanate, stearyl-isocyanate, behenyl-isocyanate, eicosanyl-isocyanate, lignoceryl-isocyanate;

^• cycloalkyl-monoisocyanate compounds, in particular cyclohexyl-isocyanate, 1-isocyanatomethyl-l, 3,3-trimethylcyclohexane.

According to the invention, the compound (B2) is a compound of formula (P):

R '- (OE) _n - (OP) _m - (OB) _p -X

(P)

in which :

o R ′ represents a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon group, comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms,

o (OE) represents an ethoxylene group,

o (OP) represents a propoxylene group,

o (OB) represents a butoxylene group,

where n represents a real number between 0 and 150,

where m represents a real number between 0 and 150,

op represents a real number between 0 and 150, o the sum of n + m + p represents a real number between 0 and 150,

o X represents a chemical group carrying a labile hydrogen which can react with an isocyanate function.

According to the invention, the hydrocarbon group R ′ advantageously represents an alkyl or alkenyl group, linear, branched or cyclic, advantageously linear or branched, comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms.

According to the invention, the hydrocarbon group R ’can also represent an aromatic group comprising from 6 to 40 carbon atoms, preferably from 6 to 32 carbon atoms.

According to the invention, the hydrocarbon group R ’can represent a radical of formula

(PG):

in which R '' represents a hydrocarbon group of formula C ₁₅ H _3i -x with x = 0, 2, 4, 6; can thus include 0, 1, 2 or 3 ethylenic unsaturations (double bond). Such a radical of formula (III) is advantageously derived from cardanol, and thus of bio-resourced and non-polluting origin.

According to the invention, the hydrocarbon group R ’can also represent a tristyrylphenyl group (TSP) of formula:

or a distyrylphenyl group (DSP) of formula:

According to the invention, the sum n + m + p varies from 0 to 150, advantageously from 1 to 150, more advantageously from 1 to 100. Preferably p is 0. According to the invention, advantageously n> m, in particular m is worth 0.

According to the invention, the sum n + m + p advantageously varies from 1 to 15, more advantageously from 8 to 12. Preferably p is 0. According to the invention, advantageously n> m, in particular m is 0.

According to the invention, the sum n + m + p advantageously varies from 1 to 8,. more advantageously from 2 to 6. Preferably p is 0. According to the invention, advantageously n> m, in particular m is 0.

According to the invention, the sum n + m + p advantageously varies from 15 to 40, more advantageously from 15 to 30, even more advantageously from 20 to 30. Preferably p is 0. According to the invention, advantageously n> m, in particular m is worth 0.

According to the invention, the sum n + m + p advantageously varies from 40 to 80, more advantageously from 50 to 70. Preferably p is 0. According to the invention, advantageously n> m, in particular m is 0.

According to the invention, X advantageously represents a group chosen from an alcohol function or an amine function. The amine function can be a primary amine function. Preferably, X represents an alcohol function.

According to the invention, the compound (B3) is a di-isocyanate.

As examples of di-isocyanate (B3), mention may be made of 1,4-butane di-isocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, 1,3- and 1,4 - cyclohexane diisocyanate, methylene bis (4-cyclohexylisocyanate), 2,6-toluene diisocyanate, 2,4-diisocyanate of toluene, 2,2'-diisocyanate of diphenylmethylene, 4,4'-diisocyanate of diphenylmethylene, diphenylmethylene 2,4'-diisocyanate, 4,4'-dibenzyl diisocyanate, 2,4'-dibenzyl diisocyanate, m-xylylene diisocyanate, l-methyl-2,4-diisocyanatocyclohexane and its combination with 1-methyl-2,6-diisocyanatocyclohexane, tetramethylxylene diisocyanate (TMXDI), trimethyl-1,6-diisocyanate hexane, and combinations thereof.

COMPOUND (O CROSSLINKING

The reaction can also be carried out in the presence of a crosslinker. The crosslinker is advantageously chosen from a polyisocyanate comprising more than 2 isocyanate functions, a polyol, a polyamine and their combinations.

According to the invention, the crosslinking polyisocyanate (C) is an isocyanate compound which comprises more than 2 isocyanate functions, for example comprising up to 3, up to 4, up to 5 or up to 6 isocyanate functions.

According to the invention, the crosslinking polyisocyanate (C) is advantageously chosen from isocyanate compounds comprising more than 2.5 isocyanate functions, preferably more than 2.6 isocyanate functions, more preferably more than 2.7 isocyanate functions, even more preferably 3 or more than 3 isocyanate functions.

As examples of crosslinking polyisocyanate (C), there may be mentioned:

• polymeric diphenylmethylene diisocyanate (PMDI), polymeric toluene diisocyanate (PTDI);

• triphenylmethane-4,4 ’, 4” -triisocyanate or l, l ’, l” -methylidynetris (4-isocyanatobenzene); or

• an isocyanurate compound, particularly an isocyanurate compound of a i ^'corhpdsé selected from:

o symmetrical aromatic diisocyanate compounds, preferably:

Diphenylmethylene 2,2'-diisocyanate (2,2'-MDI) and 4,4'-diphenylmethylene diisocyanate (4,4'-MDI);

4,4’-dibenzyl diisocyanate (4,4’-DBDI);

* 2,6-toluene diisocyanate (2,6-TDI);

_* m-xylylene diisocyanate (m-XDI); * tetramethylxylene diisocyanate (TMXDI);

o symmetrical alicyclic diisocyanate compounds, preferably methylene bis (4-cyclohexylisocyanate) (H _I2 MDI);

o the symmetrical aliphatic diisocyanate compounds, preferably hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI);

o the asymmetric aliphatic diisocyanate compounds, preferably trimethyl-1,6-diisocyanate hexane;

o the asymmetric alicyclic diisocyanate compounds, preferably isophorone diisocyanate (IPDI);

o the asymmetric aromatic diisocyanate compounds, preferably:

^■ 2,4'-diphenylmethylene diisocyanate (2,4 -MDI);

^■ 2,4'-dibenzyl diisocyanate (2,4'-DBDI);

Toluene 2,4-diisocyanate (2,4-TDI);

• a biuret, in particular a biuret of a compound chosen from:

o symmetrical aromatic diisocyanate compounds, preferably:

^■ 2,2'-diphenylmethylene diisocyanate (2,2 -MDI) and 4,4'- diphenylmethylene diisocyanate (4,4'-MDI);

^■ 4,4'-dibenzyl diisocyanate (4,4'-DBDI);

^■ toluene 2,6-diisocyanate (2,6-TDI);

m-xylylene diisocyanate (m-XDI);

tetramethylxylene diisocyanate (TMXDI);

o symmetrical alicyclic diisocyanate compounds, preferably methylene bis (4-cyclohexylisocyanate) (H12MDI);

• symmetrical aliphatic diisocyanate compounds, preferably hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI);

o the asymmetric aromatic diisocyanate compounds, preferably:

Diphenylmethylene 2,4'-diisocyanate (2,4'-MDI);

2,4’-dibenzyl diisocyanate (2,4’-DBDI);

Toluene 2,4-diisocyanate (2,4-TDI);

• and their combinations. As other examples of crosslinking compounds (C), mention may be made of polyfunctional compounds derived from condensation or from the addition of diisocyanates such as, for example, polymeric MDIs (P API) or polymeric TDIs.

As other examples of crosslinking compounds (C), there may also be mentioned:

- molecules comprising more than two alcohol functions, optionally oxyethylated beforehand, such as oses comprising from 4 to 8 carbon atoms and ose oligomers comprising from 1 to 10 ose units;

- pentaérhytritol;

- glycerol;

triethanolamine;

- glycerol oligomers, in particular glycerol oligomers having from 2 to 25 glycerol units;

- molecules comprising more than two primary or secondary amine functions such as diethylenetriamine, triethyletetramine, tetraethylenepentamine;

- the molecules comprising more than two different functions and reactive towards isocyanates, particularly the primary amines comprising an alcohol function, the secondary amines comprising an alcohol function, in particular diethanolamine.

CATALYST

Preferably according to the invention, the reaction is carried out in the presence of a catalyst. This catalyst can be chosen from acetic acid, an amine, preferably 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), a derivative of a metal chosen from Al; Bi, Sn, Hg, Pb, Mn, Zn, Zr, Ti and their mixtures. Traces of water can also participate in the catalysis of the reaction. As examples of metal derivatives, a derivative chosen from dibutyl bismuth dilaurate, dibutyl bismuth diacetate, dibutyl bismuth oxide, bismuth carboxylate, dibutyl tin dilaurate, dibutyl tin diacetate, dibutyl tin oxide, a mercury derivative is preferred. , a derivative of lead, zinc salts; manganese salts, a compound comprising chelated zirconium, a compound comprising chelated aluminum. The preferred metal derivative is chosen from a Bi derivative and a Sn derivative. In the method according to the invention, in step a), the hydrophilic polymer _; (P); is advantageously prepared by reactive extrusion of, the percentages are expressed by weight relative to the total weight of the compounds introduced:

(A) at least 55% water-soluble polyalkylene glycol (A);

(B) 5 to 45% of product (B);

(C) 0 to 10% of crosslinking compound (C).

According to the invention, the hydrophilic polymer (P) is advantageously prepared by reactive extrusion of at least 60%, more advantageously of at least 70%, even more advantageously of at least 80%, of water-soluble polyalkylene glycol (A) , the percentages are expressed by weight relative to the total weight of the compounds introduced. According to the invention, the hydrophilic polymer P is advantageously prepared by reactive extrusion from 5% to 40%, more advantageously from 5% to 30%, even more advantageously from 5% to 20%, of said product (B), the percentages are expressed by weight relative to the total weight of the compounds introduced.

According to the invention, the hydrophilic polymer (P) is advantageously prepared by reactive extrusion of 0 to 8%, more advantageously from 0 to 6%, of crosslinking compound (C), the percentages are expressed by weight relative to the total weight of the compounds introduced.

The method according to the invention provides for the reaction of these components according to a continuous process, by reactive extrusion.

Reactive extrusion is a generally known method for the preparation of thermoplastics, therefore polymers with high glass transition or melting temperatures, where appropriate, or for the preparation of polymers of high viscosity. Reactive extrusion allows all the stages (mixing, polymerization and purification / devolatilization) to be carried out in the same reactor, the extruder.

Although the polyalkylene glycol (A) is sensitive to heat, no degradation is generally observed.

Any type of extruder allowing the mixing of components can be used: single-screw extruder, two-stage or co-kneader (in English: co-kneader), twin-screw, planetary gear, rings. The twin screw extenders are particularly suitable.

The L / D ratio (length / diameter) of the extender is adapted as a function of the polymerization or polycondensation or polyaddition time, depending on the flow rate and residence time. The L / D ratio may for example be greater than or equal to 20, more advantageously greater than or equal to 30.

The processing parameters can be adapted, in particular the speed of rotation of the extruder screws, its design in the mixing zones, for example as a function of the desired mixing.

The extruder can include one or more feeding zones. Ή it is possible to premix the components before introduction into the extruder. It can also be envisaged to provide in the extruder a zone for melting some of the compounds before adding the other compounds, in particular polyalkylene glycol (A) or of the compound (B2) of formula (P) before adding the di-isocyanate. (B3) or of compound (B1) of formula (I). The extruder may include one or more heating zones. Advantageously, it includes several heating zones. The polymerization or polycondensation or polyaddition reaction is advantageously carried out at a temperature ranging from 50 ° C to 350 ° C, more advantageously ranging from 70 ° C to 300 ° C. The ; pressure can vary from 50 mbar (5.10 ³ Pa) up to 5 bar (500.10 ³ Pa). The polymerization or polycondensation or polyaddition reaction is advantageously carried out under an inert atmosphere, for example by flushing with nitrogen or argon.

Before recovery of the polymer (P) at the outlet of the extruder, the method according to the invention can comprise one or more stages of evaporation of the volatile unreacted components.

The method according to the invention makes it possible to obtain the polymer (P) with satisfactory conversion rates, in durations compatible with industrial use. In addition, the method according to the invention, compared to a batch process in a reactor, allows faster homogenization of the compounds with an increase in the rate of diffusion of the compounds and thus an improvement in the mixing.

The method according to the invention also makes it possible to access polymers (P) having higher molar masses (Mw) than those of polymers of polyurethane or polyurea type which can be obtained in a batch process in a reactor while the increase viscosity would impose a maximum limit of molar mass.

Reactive extrusion has proven to be suitable for the preparation of the polymer (P) despite the sensitivity of the polyalkylene glycol (A) to heat. It has been found that reactive extrusion saves time, with shorter cycle times compared to a batch process in a reactor.

Surprisingly, the method according to the invention also makes it possible to improve the viscosifying properties of the thickening composition according to the invention. For the same amount of polymer (P) in the thickening composition, the thickening composition comprising a polymer (P) obtained by the method according to the invention will be more thickening than the same thickening composition comprising a polymer obtained by reaction of the same compounds, in the same proportions, but according to a batch process in a reactor.

Also, the reactive extrusion allows to work without solvent. Thus, during step a), preferably, no solvent is added. This is advantageous for the environment and also for the economic cost of the method since the costs associated with a step of removing the solvent are saved.

Also, the continuous reactive extrusion method is more flexible than a batch process in a reactor and allows the ranges of polymer (P) to be varied during synthesis by variation of the compounds introduced (nature, quantity) into the zones. power supply. On the contrary, in a batch process, the compounds and their contents are fixed for each reactor.

In addition, the method according to the invention is much more reproducible than a batch process in a reactor.

Depending on the nature of the product (B), the polymer (P) will be a polyurethane or a polyurea. The polymer (P) obtained by the method according to the invention is hydrophilic, advantageously water-soluble.

Preferably for the method according to the invention, the molar mass (Mw) of the polymer (P) obtained can range up to 500,000 g / mol, advantageously it can vary from 10,000 to 500,000 g / mol, preferably from 60,000 to 500,000 g / mol.

The method according to the invention makes it possible to reach polymers (P) of high molar mass (Mw), advantageously varying from 120,000 to 500,000 g / mol, preferably ^: from 150,000 to 500,000 g / mol, preferably from 150,000 to 300,000 g / mol. The method according to the invention also makes it possible to prepare polymers (P) of lower molar mass (Mw), advantageously varying from 10,000 to 150,000 g / mol, preferably from 60,000 to 150,000 g / mol, more preferably from 60,000 to 120,000 g / mol.

According to the invention, the molecular mass of the polymer (P) is determined by Steric Exclusion Chromatography (CES) or in English "Gel Permeation Chromatography" (GPC). This technique uses a Waters brand liquid chromatography device with a detector. This detector is a Waters 2414 type refractometric concentration detector. This liquid chromatography apparatus is provided with two steric exclusion columns in order to separate the different molecular weights of the polymers studied. The liquid elution phase is an organic phase composed of THF (grade HPLC, not stabilized).

In a first step, approximately 25 mg of polyurethane is dissolved in 5 mL of THF, added with 0.1% by weight of water used as internal flow marker. Then, the solution is filtered at 0.2 μm. 50 μL are then injected into the chromatography apparatus (eluent: THF, grade HPLC, not stabilized).

The liquid chromatography device contains an isocratic pump (Waters 515), the flow rate of which is adjusted to 0.3 mL / min. The chromatography apparatus also includes an oven which includes a column system in series: an Agilent PLgel MiniMIX-A column of 250 mm length and 4.6 mm diameter followed by an Agilent PLgel MiniMIX- column B 250 mm long by 4.6 mm in diameter.

The detection system consists of a RI Waters 2414 type refractometric detector. The columns are maintained at a temperature of 35 ° C and the refractometer is brought to a temperature of 35 ° C.

The chromatography device is calibrated using polymethyl methacrylate standards certified by the supplier Agilent (EasiVial PMMA).

The thickening composition obtained by the method according to the invention comprises at least one hydrophilic polymer (P) prepared by reactive extrusion according to the method according to the invention. Due to its hydrophilic, advantageously water-soluble nature, the polymer (P) can be formulated in an aqueous medium. According to the invention, at the extruder outlet, the polymer (P) is mixed in at least one solvent.

The composition according to the invention can be aqueous or organic. In particular, the solvent can be chosen from an organic solvent, water, and combinations thereof. Preferably, the solvent is water or a water-organic solvent mixture.

In step b), an additive other than the solvent can also be added. According to the invention, the thickening composition advantageously also comprises at least one additive, in particular an additive chosen from:

• an amphiphilic compound, in particular a surfactant compound, preferably a hydroxylated surfactant compound, for example alkyl-polyalkyleneglycol, in particular alkyl-polyethyleneglycol and alkyl-polypropyleneglycol;

• a polysaccharide type derivative, for example cyclodextrin, cyclodextrin derivative, polyethers;

• a hydrotropic compound, for example glycol, butylglycol, butyldiglycol, monopropyleneglycol, ethyleneglycol, ethylenediglycol, Dowariol products (CAS number 34590-94-8), Texanol products (CAS number 25265-77-4);

• an anti-foaming agent, a biocidal agent;

• and their combinations.

The invention also provides a formulation which can be used in many technical fields. The formulation according to the invention comprises at least one thickening composition obtained by the method according to the invention and can comprise at least one organic or mineral pigment or organic, organometallic or mineral particles, for example calcium carbonate, talc, kaolin , mica, silicates, silica, metal oxides, especially titanium dioxide, iron oxides.

The formulation according to the invention can also comprise at least one agent chosen from a particle spacing agent, a dispersing agent, a steric stabilizing agent, an electrostatic stabilizing agent, an opacifying agent, a solvent, a _. coalescing agent, defoaming agent, preservative, biocidal agent, spreading agent, thickening agent, film-forming copolymer and mixtures thereof. Depending on the particular polymer (P) or the additives that it comprises, the formulation according to the invention can be implemented in numerous technical fields. Thus, the formulation according to the invention can be a coating formulation. Preferably, the formulation according to the invention is an ink formulation, an adhesive formulation, a varnish formulation, a paint formulation, for example decorative paint or industrial paint.

The invention also provides a concentrated aqueous pigment paste comprising at least one thickening composition obtained by the method according to the invention and at least one organic or inorganic colored pigment.

The thickening composition obtained by the method according to the invention has properties allowing it to be used to modify or control the rheology of the medium comprising it. Thus, the invention also provides a method for controlling the viscosity of an aqueous composition.

This viscosity control method according to the invention comprises the addition of at least one thickening composition, obtained by the method according to the invention, in an aqueous composition.

The following examples illustrate the various aspects of the invention.

For the examples according to the invention, a TSA co-rotating twin-screw extruder is used, the geometric parameters of which are: Diameter = 26 mm and Length / Diameter ratio = 80, equipped with a gas introduction device (for example nitrogen or depleted air) and a gas exhaust system. The tests are carried out in an uncontrolled atmosphere. The tests are carried out at atmospheric pressure.

The twin-screw extruder has 16 zones whose temperature is independently controlled. They can be electrically heated and cooled using water circulation. The zone called 1 is located under the hopper, the zone 16 corresponds to the sector. The other zones are numbered 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, in this order between zone 1 and zone 16. Each zone has a length equal to 5 screw elements.

The reagents can be stored in heated, agitated, inerted tanks, equipped with pumps allowing the direct injection of the reagents into the extruder.

The flow rates of each pump can be independently controlled to control the ratios between the different reagents as well as the overall flow rate. It is thus possible to adjust the residence time in the extruder. The residence time can be measured by adding a colored tracer.

The viscosity of unformulated polyurethane is measured using a weight extrusion plastometer, the die of which is 8 mm long with an internal diameter of 2.096 mm. A 2.16 kg piston is placed on the sample to be measured melted at 100 ± 1 and the time necessary for a quantity of said sample to flow out of the die makes it possible to determine the value of melt index or MVR (melt volume rate) expressed in cm ³ / l0 min.

Example 1

Trial 1

This example illustrates the production of one HEUR by addition of polyethylene glycol (PEG), of cardanol (CAS number: 37330-39-5) ethoxylated with isophorone diisocyanate (IPDI) in the presence of a catalyst.

The polyethylene glycol used has approximately 230 repeating units, the ethoxylation length of cardanol is approximately 4 units of ethylene oxide and the catalyst used is dibutyltin dilaurate (DBTDL).

The PEG / ethoxylated cardanol / DBTDL mixture is placed in a sealed tank heated to 90 ° C., under vacuum and dehydrated until a water level of less than 800 ppm is obtained. This tank is then inerted with nitrogen.

The IPDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

In this example, zone 1 is heated to 25 ° C. The other 15 zones are heated to 120 ° C.

The residence time of the reaction medium in the extruder is between 8 and 10 minutes for a flow rate of 3.05 kg / h (0.18 kg / h IPDI; 2.6 kg / h PEG; 0.27 kg / h ethoxylated cardanol). The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / cosolvent mixture (OXO CIO alcohol ethoxylates - Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% of polyurethane base, 20% of cosolvent and 50% water. Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 216 kg) = 45 cm ^3/10 min. Trial 2

This example illustrates the production of a HEUR by adding polyethylene glycol, ethoxylated cardanol with IPDI in the presence of a catalyst.

The polyethylene glycol used has approximately 230 repeating units, the ethoxylation length of cardanol is approximately 4 units of ethylene oxide and the catalyst used is dibutyltin dilaurate.

The PEG / ethoxylated cardanol / DBTDL mixture is placed in a sealed tank heated to 90 ° C. under vacuum and dehydrated until a water level of less than 800 ppm is obtained. This tank is then inerted with nitrogen.

The EPDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

The residence time of the reaction medium in the extruder is between 5 and 7 minutes for a flow rate of 4.58 kg / h (0.27 kg / h IPDI; 3.9 kg / h PEG; 0.41 kg / h ethoxylated cardanol). The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / co-solvent mixture (Suifaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% of polyurethane base, 20% of co-solvent and 50% of water . Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.16 kg) = 62 cm ^3/10 min.

Trial 3

The PEG / ethoxylated cardanol / DBTDL mixture is placed in a sealed tank heated to 90 ° C. under vacuum and dehydrated until a water level of less than 800 pprik is obtained. This tank is then inerted with nitrogen.

The IPDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

In this example, zone 1 is heated to 25 ° C. The other 15 zones are heated to The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.29 kg / h (0.14 kg / h IPDI; 1.95 kg / h PEG; 0.20 kg / h ethoxylated cardanol).

The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / co-solvent mixture (Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% of polyurethane base, 20% of co-solvent and 50% of water . Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.l6 kg) = 21 cm ^3/10 min.

Trial 4

This example illustrates the production of a HEUR by addition of polyethylene glycol, of ethoxylated cardanol with toluene diisocyanate (TDI 80/20) in the presence of a catalyst.

The TDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

The residence time of the reaction medium in the extruder is between 8 and 10 minutes for a flow rate of 4.52 kg / h (0.22 kg / h TDI; 3.90 kg / h PEG; 0.40 kg / h ethoxylated cardanol). The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / co-solvent mixture (Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% of polyurethane base, 20% of co-solvent and 50% of water . Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.16 kg) = 13 c ^3/10 min. Trial 5

This example illustrates the production of a HEUR by addition of polyethylene glycol, of ethoxylated cardanol with H12MDI in the presence of a catalyst.

The H12MDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.31 kg / h (0.16 kg / h H12MDI; 1.95 kg / h PEG; 0.20 kg / h ethoxylated caudanol).

The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / cosolvent mixture (Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% polyurethane base, 20% cosolvent and 50% water. . Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.l6 kg) = 19 cm ³ / l0 min.

Trial 6

This example illustrates the production of a HEUR by addition of polyethylene glycol, of ethoxylated cardanol with HDI in the presence of a catalyst.

The HDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen. In this example, zone 1 is heated to 25 ° C. The other 15 zones are heated to 120 ° C.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.25 kg / h (0.10 kg / h HDI; 1.95 kg / h PEG; 0.20 kg / h ethoxylated cardanol). The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / co-solvent mixture (Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% of polyurethane base, 20% of co-solvent and 50% of water . Part of the unformulated resin is kept in order to make a measurement of MVR. (melt volume rate).

MVR (100 ° C / 2.l6 kg) = 29 cm ³ / l0 min.

Trial 7

This example illustrates the production of a HEUR by addition of polyethylene glÿcol, of ethoxylated cardanol with HDI in the presence of a catalyst.

The HDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

In this example, zone 1 is heated to 25 ° C. The other 15 zones are heated to 130 ° C.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.25 kg / h (0.10 kg / h HDI; 1.95 kg / h PEG; 0.20 kg / h ethoxylated cardanol). The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in a water / co-solvent mixture (Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% of polyurethane base, 20% of co-solvent and 50% of water . Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ⁰ C / 2.16 kg) = 12 cm ^3/10 min. Trial 8

The PEG / ethoxylated cardanol / DBTDL mixture is placed in a sealed tank heated to 90 ° C. under vacuum and dehydrated until a water level of less than 800 pphi is obtained. This tank is then inerted with nitrogen.

The HDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

In this example, zone 1 is heated to 25 ° C. Zones 2, 3, 4 are heated to 170 ° C, the other zones are heated to 120 ° C.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.25 kg / h (0.10 kg / h HDI; 1.95 kg / h PEG; 0.20 kg / h ethoxylated cardanol). The product obtained at the outlet of the extruder is in the form of a molten resin. D is formulated directly at the outlet of the die in a water / cosolvent mixture (Surfaline 0x1008 from the company Arkema) so that the final formulation contains by weight 30% polyurethane base, 20% cosolvent and 50% water . Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.l6 kg) = 9.2 cm ^3/10 min.

Trial 9

The HDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen. In this example, zone 1 is heated to 25 ° C. Zones 2, 3, 4, 5, 6 are heated to 170 ° C, the other zones are heated to 120 ° C.

MVR (100 ⁰ C / 2.16 kg) = <5 cm ^3/10 min.

Trial 10

This example illustrates the production of a HEUR by addition of polyethylene glycol, of tristyryl phenol (TSP) ethoxylated with IPDI in the presence of a catalyst.

The polyethylene glycol used has approximately 230 repeating units, the TSP ethoxylation length is approximately 3 units of ethylene oxide and the catalyst used is dibutyltin dilaurate.

The PEG / ethoxylated TSP / DBTDL mixture is placed in a sealed tank heated to 90 ° C. under vacuum and dehydrated until a water level of less than 800 ppm is obtained. This tank is then inerted with nitrogen.

The IPDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

In this example, zone 1 is heated to 25 ° C. Zones 2, 3, 4, 5, 6 are heated to 170 ° C, the other zones are heated to 120 ° C.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.25 kg / h (0.10 kg / h IPDI; 1.95 kg / h PEG; 0.20 kg / h TSP ethoxylated).

The product obtained at the outlet of the extruder is in the form of a foam resin. It is formulated directly at the outlet of the die in a water / cosolvent mixture (linear alcohol in C8 ethoxylated 80E - Surfaline CC8 from the company Arkema) so that the final formulation contains 30% by weight of polyurethane base, 20% by weight. cosolvent and 50% water. Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.16 kg) = 14 cm ^3/10 min. Trial 11

This example illustrates the production of one HOUR by adding polyethylene glycol, hexan-l-ol with H12MDI in the presence of a catalyst.

The polyethylene glycol used has approximately 230 repeating units and the catalyst used is dibutyltin dilaurate.

The PEG is placed in a sealed tank heated to 90 ° C under vacuum and dehydrated until a water level below 800 ppm is obtained. Hexan-l-ol and DBTDL are added and this tank is then inerted with nitrogen.

The H12MDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

In this example, zone 1 is heated to 25 ° C. The other zones are heated to 120 ° C. The residence time of the reaction medium in the extruder is between 5 and 7 minutes for a flow rate of 4.31 kg / h (0.32 kg / h H12MDI; 3.9 kg / h PEG; 0.09 kg / h hexan-l-bl).

The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in water so that the final formulation contains by weight 20% of polyurethane base and 80% of water, respectively. Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.16 kg) = 51 cm ^3/10 min.

Trial 12

This example illustrates the production of a HEUR by addition of polyethylene glycol, of hexan-l-ol with methylene bis (4-cyclohexylisocyanate) (H12MDI) in the presence of a catalyst.

The polyethylene glycol used has approximately 230 repeating units and the catalyst used is 1,8-diazabicyclo (5, 4, 0) undec-7-ene (DBU).

The PEG is placed in a sealed tank heated to 90 ° C under vacuum and dehydrated, ju-squ ’to obtain a water level of less than 800 ppm. Hexan-l-ol and DBU are added and this tank is then inerted with nitrogen.

The H12MDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.16 kg / h (0.16 kg / h H12MDI; 1.95 kg / h PEG; 0.5 kg / h hexan-l-ol). The product obtained at the extruder outlet is in the form of a resinous resin. It is formulated directly at the outlet of the die in water so that the final formulation contains 20% by weight of polyurethane base and 80% water respectively. Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.16 kg) = 16 cm ^3/10 min.

Trials 13-a and! 3-b

This example illustrates the production of a HEUR by addition of polyethylene glycol, of hexan-l-ol with H 12MDI in the presence of a catalyst.

The polyethylene glycol used has approximately 230 repeating units, the ethoxylation length of cardanol is approximately 4 units of ethylene oxide and the catalyst used is 1,8-diazabicyclo (5, 4, 0) undec-7 -ene (DBU).

The PEG is placed in a sealed tank heated to 90 ° C under vacuum and dehydrated until a water level below 800 ppm is obtained. Hexan-l-ol and DBU are added and this tank is then inerted with nitrogen.

The H12MDI is placed in a sealed tank heated to 60 ° C inerted with nitrogen.

The residence time of the reaction medium in the extruder is between 11 and 14 minutes for a flow rate of 2.16 kg / h (0.16 kg / h H12MDI; 1.95 kg / h PEG; 0.05 kg / h hexan-l-ol). The product obtained at the outlet of the extruder is in the form of a molten resin. It is formulated directly at the outlet of the die in water so that the final formulation contains 20% by weight of polyurethane base and 80% water, respectively. · Part of the unformulated resin is kept in order to make a MVR (melt volume rate) measurement.

MVR (100 ° C / 2.l6k g) = 18 cm ^3/10 min (l3-a).

The pump flow rates are then modified in order to increase the overall flow rate to 4.31 kg / h (0.32 kg / h H12MDI; 3.9 kg / h PEG; 0.09 kg / h hexan-l-ol) . After balancing for 15 minutes, the residence time is measured by adding a colored tracer to approximately 5 to 7 minutes.

MVR (100 ⁰ C / 2.16 kg) = 24 cm ³ / l0 min (l3-b). Trial 14 (comparison)

This test corresponds to a polyurethane, resulting from the condensation, expressed in% by weight, of each of the constituents:

85.2% polyethylene glycol having 230 repeating ethylene oxide units,

8.9% oxyethylated cardanol with 4 ethylene oxide units,

5.9% isophorone diisocyanate.

260 g of PEG containing 230 repetitive units of ethylene oxide and 27 g of oxyethylated cardanol are introduced into 1 glass reactor of 1L equipped with mechanical stirring of the anchor type and a vane pump to generate vacuum. 4 ethylene oxide units. This mixture is heated to 80 ° C using a balloon heater. The reactor is placed under vacuum to dry the mixture. When the water level, measured with a Karl-Fischer type device is less than 800 ppm, 200 ppm of DBTDL and then 18 g of IPDI are introduced. The addition reaction is allowed to continue for 1 hour.

Part of the polyurethane obtained is formulated in water in the presence of a surfactant sold under the name Surfaline 0x1008 by the company Arkema (weight ratio: 30% PU, 20% Surfaline 0x1008, 50% water). A sufficient quantity is extracted before formulation in order to be able to carry out a measurement of MVR.

MVR (100 ° C / 2.16 kg) = 66 cm ^3/10 min.

Trial 15 (comparative)

90.5% of polyethylene glycol having 230 repeating units of ethylene oxide,

8.9% hexan-l-ol,

- 7.4% of Hl2MDI.

195 g of PEG containing 230 repetitive units of ethylene oxide are introduced into 1 glass reactor of 1 L equipped with mechanical stirring of the anchor type and a vane pump to generate vacuum. The PEG is heated to 80 ° C by means of a balloon heater. The reactor is placed under vacuum in order to dry it. When the water content, measured with a Karl-Fischer type device is less than 800 ppm, 4.5 g of hexan-l-ol, 200 ppm of DBTDL and then 16 g of H12MDI are introduced in order . The addition reaction is allowed to continue for 1 hour. Part of the polyurethane obtained is formulated in water (weight ratio: 20% PU, 80% water). A sufficient quantity is extracted before formulation in order to be able to carry out a MVR measurement.

MVR (100 ° C / 2.l6 kg) = 72 cm ³ / l0 min.

Example 2

This example illustrates the use of polyurethanes according to the invention and comparatives, as thickening agents in a matte paint without solvent.

The paint composition is detailed in Table 1, the masses of each component being indicated in grams. The thickeners all have a dry extract of 30% by weight of active material. The paint is formulated according to known methods.

Table 1 The resulting viscosities are then determined at different speed gradients:

- at low gradient: Brookfield ™ viscosity at 10 and 100 revolutions / minute, respectively denoted VB10 and VB100 (mPa.s),

- at medium gradient: Stormer viscosity (Krens Unit, KU),

high gradient: ICI viscosity (0.1 Pa.s).

These measurements are made 24 hours after preparation of the formulation. The formulations are thermostatically controlled at 25 ± 0.5 ° C. It will be recalled that, in the field of aqueous paints, a high viscosity with a high shear gradient translates good dynamic behavior. In practice, the viscosity of the paint remains sufficiently high during the application step on the support. Profits can be a filling (that is to say a thickness déposéèj ^important addition and a propensity to reduced splashes.

At the same time, a high viscosity at a low or medium shear gradient indicates good static behavior. This ensures good stability during storage while avoiding the phenomenon of sedimentation and a limitation of the tendency to run on a vertical support. Examples A1 to A14 were carried out using the thickener produced during the corresponding tests 1 to 14 of Example 1.

Table 2

These results demonstrate that the polyurethane compositions according to the invention make it possible to effectively thicken a matt paint without solvent, whatever. that is to say the shear gradient. In addition, the polyurethanes according to test A4, A5, A7, A8, A9 offer higher performance than that of the reference A14.

The viscosities obtained at high shear gradient are preserved, the viscosities measured at medium and low shear gradient are significantly improved. The effectiveness of these polyurethanes as pseudoplastic additives is better. Example 3

This example illustrates the use of polyurethanes according to the invention and comparatives, as thickening agents of a formulation with thickening latex.

The composition of the formulation is detailed in Table 3, the masses of each constituent being indicated in grams.

The thickeners all have a dry extract of 20% by weight of active material. The formulation is carried out according to methods known to those skilled in the art.

Table 3

The resulting viscosities are then determined at different speed gradients:

low gradient: Brookfïeld ™ viscosity at 10 revolutions / minute, respectively denoted VB 10 (in mPa.s),

- at medium gradient: Stormer viscosity (Krens Unit, KU),

high gradient: ICI viscosity (0.1 Pa.s).

These measurements are made 1 hour after preparation of the formulation. The formulations; soht thermostatically controlled at 25 ± 0.5 ° C.

Table 4 These results demonstrate that the polyurethanes according to the invention make it possible to effectively thicken a water / latex mixture neutralized at pH = 8.5 whatever the shear gradient. In addition, the polyurethanes according to tests A1, 12, A13-a, A13-5; offer higher performance than the A 15 reference.

The viscosities obtained at high and low shear gradient are significantly higher, the viscosities measured at medium shear gradient are significantly improved. The effectiveness of these polyurethanes as Newtonian additives is better.

Claims

1. Method for preparing a thickening composition comprising:

(A) of at least one water-soluble polyalkylene glycol (A) chosen from a polyethylene glycol, a polyethylene glycol - polypropylene glycol copolymer containing at most 40% of polypropylene glycol weight, a polyethylene glycol - polybutylene glycol copolymer containing at most 20% by weight of polybutylene glycol, and combinations thereof;

(B) of at least one product (B), comprising at least one associative group and at least one isocyanate function, and chosen from:

• a compound (B1) of formula (I):

R-N = C = 0

(D

• a combination of a di-isocyanate (B3) and a compound (B 2) of formula (P):

R '- (OE) _n - (OP) _m - (OB) _p -X

(P)

in which :

o R 'represents a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon group, comprising from 6 to 40 carbon atoms, o (OE) represents an ethoxylene group, o (OP) represents a propoxylene group, o (OB) represents a group _{butoxylène,;}

we represent a real number between 0 and 150, om represents a real number between 0 and 150, op represents a real number between 0 and, 150, where the sum of n + m + p represents a real number between 0 and 150,

• the product resulting from the prior condensation of a di-isocyanate (B3) and a compound (B2) of formula (P),

• a combination of a di-isocyanate (B3) and a compound (B 1) of formula (I),

• and their combinations;

b. mixing the water-soluble polymer (P) in at least one solvent.

2. Method according to claim 1, for which the compound (A) is a polyalkylene glycol having a molar mass by mass (Mw) ranging from 1,000 to 40,000 g / mol, preferably from 3,000 to 20,000 g / mol , more preferably from 4,000 to 15,000 g / mol.

3. Method according to one of the preceding claims, for which X is chosen from an alcohol function or an amine function, preferably an alcohol function.

4. Method according to one of the preceding claims, for which the di-isocyanate (B3) is chosen from 1,4-butane di-isocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, 1,3- and 1,4- cyclohexane diisocyanate, methylene bis (4-cyclohexylisocyanate), 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 2,2'-diphenylmethylene diisocyanate , diphenyl methylene 4,4'-diisocyanate, diphenyl methylene 2,4'-diisocyanate, 4,4'-dibenzyl diisocyanate, 2,4'-dibenzyl diisocyanate, m-xylylene diisocyanate, 1-methyl- 2,4-diisocyanatocyclohexane and its combination with 1-methyl-2,6-diisocyanatocyclohexane, tetramethylxylene diisocyanate (TMXDI), trimethyl-1,6-diisocyanate hexane, and combinations thereof.

5. Method according to one of the preceding claims, for which the reactive extrusion also implements at least one crosslinking compound (C), advantageously chosen from a polyisocyanate comprising more than 2 isocyanate functions, a polyol, a polyamine and their combinations .

6. Method according to one of the preceding claims, in which the reactive extrusion also uses a catalyst, preferably a catalysis chosen from acetic acid, an amine, at least one derivative of a metal chosen from Al, Bi, Sn, Hg, Pb, Mn, Zn, Zr and Ti, and mixtures thereof.

7. Method according to one of the preceding claims, for which the hydrophilic polymer (P) is prepared by reactive extrusion of, the percentages are expressed by weight relative to the total weight of the compounds introduced:

(A) at least 55% water-soluble polyalkylene glycol (A);

(B) 5 to 45% of product (B);

(C) 0 to 10% of crosslinking compound (C).

8. Method according to one of the preceding claims, for which the solvent of step b) is chosen from water, an organic solvent and their combinations, preferably water.

9. Method according to any one of the preceding claims, for which, in addition to the solvent, the hydrophilic polymer (P) is mixed, in step b), with an additive chosen from an amphiphilic compound, a polysaccharide derivative, a compound hydro trope, an anti-foaming agent, a biocidal agent, and combinations thereof.