CA2345326A1 - Use of essentially amorphous cellulose nanofibrils as emulsifying and/or stabilising agent - Google Patents

Abstract

The invention concerns the use of essentially amorphous cellulose nanofibrils having a crystallinity index not more than 50 % as emulsifying and/or stabilising agent in a dispersion. The nanofibrils can be used in the form of an aqueous suspension, or in dispersible dry form. Said nanofibrils can also be used in combination with at least an additive and optionally at least a co-additive.

Description

USE OF ESSENTIALLY CELLULOSE NANOFIBRILLES
AMORPHOUS AS AN EMULSIFYING AND / OR STABILIZING AGENT
The present invention relates to the use of nanofibrils of cellulose essentially amorphous with a crystallinity rate less than or equal to 50%, as an emulsifying and / or stabilizing agent for a dispersion.
It also relates to the use of the aforementioned nanofibrils with at minus one.
additive and optionally with at least one co-additive.
Within the meaning of the invention, a dispersion designates a system consisting of at least two immiscible phases.
It can correspond for example - a liquid-in-liquid emulsion, the liquids being immiscible one in the other, in particular an oil in water emulsion, or a water in oil emulsion;
- a multiple emulsion consisting for example of three liquids, of which minus 2 are immiscible with each other, in particular a water in oil in water emulsion or oil in water in oil, the water and oil phases possibly being identical or different;
- a foam consisting of gas dispersed in a liquid or an emulsion;
- an emulsion or suspension of solid in a liquid, such as latex which correspond to colloidal suspensions of polymer particles in a liquid phase;
- a system formed by a gas and two different liquids.
The object of the present invention applies to any dispersion such as defined more above, and more particularly to the systems listed in a nonlimiting manner.
At this stage, it is important to define the terms "emulsifier" and "stabilizing".
In the context of the present invention, the term "emulsifier" denotes a compound which lowers the interfacial tension between two immiscible phases (through water / oil example) and thus allows a large increase in the surface specific of the phase to be emulsified. Thus, (mechanical energy required to form the dispersion is decreased.
The emulsifier may or may not subsequently stabilize the emulsion in a lasting manner in for example bringing charges to the surface of the droplets "stabilization electrostatic".
By "stabilizer" is meant any compound which will slow down or even inhibit the destabilization phenomena of (emulsion or dispersion, i.e.
the creaming or flocculation which sooner or later lead to the coalescence of droplets or the coagulation of solids in a dispersion. The stabilizer can exercise his function in different ways - either by adsorbing on the surface of the droplets without necessarily lower their interfacial tension and stabilizing them sterically,

2 - either by structuring and viscosating the medium so that the speed creaming droplets or flocculation of solids is slowed.
We can say that the stabilizer performs its function by forming a kind of mechanical barrier preventing droplets from creaming or solids from flocculate.
5 Stabilization and emulsification are therefore two separate functions But complementary.
It should be noted that the operating conditions, such as for example the nature of the phases, concentration, pH, ionic strength, temperatures etc., favoring faction of an emulsifier, do not necessarily favor that of a stabilizer.
Many compounds are thus known for their function as as an emulsifier or as a stabilizer. Rarer are those who exercise in a way both functions at the same time, at low concentrations and for a great number of different systems.
By way of indication, mention may be made of xanthan gum, carrageenans, alginates Or carboxymethylcelluloses, polysaccharides which are known as agents stabilizers for emulsions but not as an emulsifier.
A counter example is gum arabic which has an emulsifying power and stabilizing but at high concentrations.
However, the Applicant has unexpectedly and surprisingly found that the 20 essentially amorphous cellulose nanofibrils with a rate of crystallinity is less than or equal to 50% possessed emulsifying properties and / or stabilizers remarkable.
Said nanofibrils according to the invention can be both an agent emulsifier and / or stabilizing at relatively low, fully comparable amounts those 25 of the usual emulsifiers such as TWEEN 20 (polyoxyethylene sorbitan monolaurate) and much lower than gum arabic.
Other advantages and characteristics of the present invention will become apparent more clearly reading the description and the examples which follow.
The present invention therefore relates to the use of nanofibrils of cellulose Essentially amorphous with a lower crystallinity level or equal to 50%, as an emulsifying and / or stabilizing agent for a dispersion.
More particularly, the invention relates to the use of nanofibrils of essentially amorphous cellulose with a crystallinity rate less than or equal to 50% as an emulsifying and stabilizing agent for a dispersion In the present invention, the nanofibrils are used in one amount sufficient to emulsify and / or stabilize.
In particular, the nanofibrils may be present in an amount understood between 0.01 to 5% by weight relative to the total weight of the dispersion.

3 According to an advantageous embodiment of the invention, the nanofibrils are present in an amount between 0.05 to 1% by weight, preferably between 0.1 and 0.8% by weight relative to the total weight of the dispersion.
By essentially amorphous, we mean nanofibrils whose rate of crystallinity is less than or equal to 50%. According to a particular variant of the current invention, the degree of crystallinity is between 15% and 50%. Of preferably the rate crystallinity is less than 50%.
The cellulose nanofibrils used in the composition of the formulation according to the present invention are derived from cells preferably made up of at least less about 80% of primary walls.
We have such characteristics with cellulose based on parenchyma. For example, citrus, such as lemons, grapefruits especially, or sugar beet, are plants comprising such cells.
Preferably, the quantity of primary walls is at least 85% by weight.
More in particular, we use cellulose from pulp beet sugar.
According to a preferred variant, the nanofibrils of the invention exhibit at less 80% of cells with primary walls.
The nanofibrils are advantageously charged at the surface with acids carboxylic and acid polysaccharides, alone or as a mixture.
By carboxylic acids is meant simple carboxylic acids, as well than their salts. These acids are preferably chosen from uronic acids, or their salts. More particularly, said uronic acids are the acid galacturonic acid glucuronic, or their salts.
As acidic polysaccharides, mention may be made of pectins, which are more particularly polygalacturonic acids. These acidic polysaccharides can be present in mixture with hemicelluloses.
A very advantageous embodiment of the invention consists of nanofibrils whose surface is at least charged with galaturonic acid and / or acid polygalacturonic.
It should be noted that this is not a simple mixture between said nanofibrils and acids and polysaccharides, but rather a close combination between these two types of compounds. Indeed, the process for preparing nanoofibrils is such as acids and polysaccharides are not completely separated from the fibers but stay still on the surface of the latter, giving them good properties specific.
Thus, it was found that it was not possible to obtain the same properties if these acids and / or polysaccharides were completely separated from the nanofibrils during of their preparation to be added later.

WO 00/16889 PCT / F'R99 / 02159

4 The cellulose nanofibrils also have a cross section Between about 2 and about 10 nm. More specifically, the microfibrils is between about 2 and about 4 nm.
The particular microfibrils used in the composition of formulations have such characteristics due to the work of a very specific preparation process, which will now be described.
It should be noted that this process is among other things the subject of the request for patent EP 726 356, to which reference may be made for more details.
First of all, said process is more particularly carried out on pulp of sugar beet after it has undergone a preliminary extraction step of sucrose, according to methods known in the art.
The preparation process includes the following steps (a) first acid or basic extraction, at the end of which a first solid residue, (b) possibly second extraction carried out under alkaline conditions of first solid residue, after which a second residue is recovered solid, (c) washing the first or second solid residue, (d) optionally bleaching the washed residue, {e) dilution of the third solid residue obtained at (from step (d) of way to obtain a dry matter content of between 2 and 10% by weight, (f) homogenization of the diluted suspension.
In step {a), the term "pulp" means moist, dehydrated pulp, preserved by silage or partially defected.
The extraction step (a) can be carried out in an acid medium or in a medium basic.
For acid extraction, the pulp is suspended in a solution of water for a few minutes so as to homogenize the acidified suspension has a pH between 1 and 3, preferably between 1.5 and 2.5.
This operation is carried out with a concentrated solution of an acid such than hydrochloric acid or sulfuric acid.
This step may be advantageous for removing the oxalate crystals from calcium which may be present in the pulp, and which, due to their character abrasive important, can cause difficulties in the homogenization step.
For basic extraction, the pulp is added to an alkaline solution of a base, for example soda or potash, with a concentration lower than 9% in weight, more particularly less than 6% by weight. Preferably, the concentration of the base is between 1 and 2% by weight.
We can add a small amount of an antioxidant agent soluble in water as than sodium sulfite Na2S03, in order to limit the oxidation reactions of cellulose.

Stage (a) is generally carried out at a temperature of between approximately 60 ° C and 100 ° C, preferably between about 70 ° C
and 95 ° C.
The duration of (step (a) is between approximately 1 hour and approximately 4 hours.
During (step (a), there is a partial hydrolysis with release and

5 solubilization of most of the pectins and hemicelluloses, all in preserving the molecular weight of the cellulose.
The solid residue is recovered from the suspension from (step (a) in using known methods. So it is possible to separate the residue solid by centrifugation, by vacuum or pressure filtration, with the canvases filters, or filter presses for example, or by evaporation.
The first solid residue obtained is optionally subjected to a second step extraction, carried out under alkaline conditions.
A second extraction step is implemented when the first has been driving under acidic conditions. If the first extraction has been carried out in alkaline conditions, the second step is only optional.
According to the method, this second extraction is carried out with a base of preference chosen from soda or potash, the concentration of which is lower than about 9% by weight, preferably between about 1% and about 6%
in weight.
The duration of (alkaline extraction step is between about 1 and about 4 hours. It is preferably equal to approximately 2 hours.
At the end of this second extraction, if it takes place, we recover a second residue solid.
In (step (c) the residue from (step (a) or (b) is washed thoroughly at Skin in order to recover the residue of cellulosic material.
The cellulosic material of step (c) is then optionally bleached, in (step (d), according to conventional methods. For example, one can perform a treatment with sodium chlorite, with sodium hypochlorite, with hydrogen peroxide with Reason to 5-20% compared to the quantity of dry matter treated.
Different concentrations of bleach can be used, except of temperatures between about 18 ° C and 80 ° C, preferably between about 50 ° C
and 70 ° C.
The duration of this step (d) is between approximately 1 hour and approximately 4 hours, preferably between about 1 and about 2 hours.
A cellulosic material containing between 85 and 95% by weight is then obtained.
of cellulose.
At (after this bleaching step, it may be preferable to wash abundantly cellulose with water.

6 . The resulting suspension, possibly bleached, is then rediluted in of water at a rate of 2 to 10% of dry matter, then undergoes a stage homogenization.
This corresponds to mixing, grinding or any shearing operation high mechanical, followed by one or more passages of the suspension cells to through a small diameter orifice, subjecting the suspension to a fall of pressure at least 20 MPa and a high speed shearing action followed by a impact.
deceleration at high speed.
The mixing or grinding is, for example, carried out by passages) in the mixer or grinder for a period ranging from a few minutes to about an hour, in a type device such as a WARING BLENDOR equipped with a four-blade propeller or wheel mill or any other type of mill, such as a colloid mill.
The actual homogenization will advantageously be carried out in a homogenizer of the MANTON GAULIN type in which the suspension is subjected to shearing action at high speed and pressure in a passage narrow and against a shock ring. We can also cite the MICRO FLUIDIZER which is a homogenizer mainly consisting of a compressed air motor which creates very strong pressures, of an interaction chamber in which is carried out the operation homogenization (elongational shear, shock and cavitation) and a bedroom low pressure which allows the depressurization of the dispersion.
The suspension is introduced into the homogenizer preferably after preheating at a temperature between 40 and 120 ° C, preference included between 85 and 95 ° C.
The temperature of the homogenization operation is maintained between 95 and 120 ° C, preferably greater than 100 ° C.
The suspension is subjected in the homogenizer to pressures included between 20 and 100 MPa, and preferably greater than 50 MPa.
The homogenization of the cellulosic suspension is obtained by a number of passages can vary between 1 and 20, preferably between 2 and 5, up to obtaining of a stable suspension.
The homogenization operation can advantageously be followed by an operation high mechanical shear, for example in a device such as ULTRA
TURRAX
from SYLVERSON.
It should be noted that this process has been described in the European patent application EP 726 356 filed on 07/02/96, we can therefore refer to it if necessary.
Example 20 of this text gives in particular a method of preparing a suspension of essentially amorphous cellulose nanofibrils.
In the context of this invention, nanofibrils can be used under form of aqueous suspension, as obtained by the process described above.

7 According to a particular embodiment of (invention the nanofibrils of cellulose can be combined with at least one polyhydroxylated organic compound (polyOH).
More particularly, the polyhydroxylated compound (polyOH) is chosen from carbohydrates and their derivatives, and polyols.
5 With regard to carbohydrates, we can particularly to quote linear or cyclic monosaccharides in C-3 to C-6, and preferably in C-5 or C-6, oligosaccharides, polysaccharides and their fatty derivatives such as fatty acid sucroesters or sucroesters, alcohol carbohydrates and their mixtures.
10 As nonlimiting examples of monosaccharides, the fructose, the mannose, galactose, glucose, talose, gulose, fallose, faltrose, idosis, farabinose, xylose, lyxose and ribose.
As oligosaccharides, mention may be made, among others, of sucrose, maltose and lactose.
15 The polysaccharides can be of animal, vegetable or even bacterial.
In addition, they can be used in an anionic form or not ionic.
Xanthan gum, succinoglycans, carrageenans, alginates are 20 representative elements of anionic polysaccharides.
With regard to nonionic polysaccharides, mention may be made in particular the galactomannans, such as guar gum, locust bean gum, starch and its non-ionic derivatives, non-ionic derivatives of cellulose.
As for the carbohydrate derivatives, we can mention without intention of 25 be limited thereto, fatty acid sucroesters, fatty acid esters, hydrates carbon of sorbitol-type alcohols, mannitol; carbohydrates acids like gluconic acid, uronic acids, such as galacturonic acid, acid glucuronic, and their salts, and carbohydrates of ethers like the carboxymethylated cellulose.
30 With regard to polyols, it is possible to use in the formulations food, glycerol, pentaerythritol, propylene glycol, ethylene glycol and / or polyvinyl alcohols.
It should be noted that the compounds described above can be used alone or mixed.
35 When this particular embodiment is implemented, the (s) compounds) organic) polyhydroxylated (polyOH) (s) is associated) with nanofibrils of cellulose in a weighted ratio (polyOH) (s) x 100 I [(polyOH) (s) + (NFC) J included between 5 and 50%, and preferably between 5 and 30%.

8 Quite advantageously, this ratio is between 10 and 30% and of preferably between 15 and 30% by weight.
According to a first particularly advantageous variant, the compound polyhydroxylated is at least carboxymethylated cellulose.
Cellulose is a polymer made up of monomeric units of glucose. The carboxyl group is introduced in a manner known per se, by reacting acid '~~
chloroacetic with cellulose.
The degree of substitution corresponds to the number of carboxymethyl groups per unit of glucose. The maximum theoretical degree is 3.
Depending on whether the degree of substitution is greater than 0.95, or less than or equal at this value, it is specified that the carboxymethylated cellulose is, respectively, high or with a low degree of substitution. Preferably, carboxymethylcellulose presents a degree of substitution is greater than 0.95.
According to a second variant, the polyhydroxylated compound is a combination of carboxymethylated cellulose with at least one of the compounds chosen from monosaccharides, oligosaccharides, nonionic polysaccharides and anionic and their derivatives, carbohydrate derivatives such as hydrates of carbon alcohols, acids and ethers.
In particular, the carboxymethylated cellulose is used in combination with at least one of the following compounds: xanthan gum, sorbitol, sucrose.
Optionally, the cellulose nanofibrils can be combined, in addition to the aforementioned polyhydroxylated compound, with at least one co-additive chosen from carboxylated cellulose with a lower or equal degree of substitution at.
0.95, preferably carboxymethylated cellulose, osidic monomers or oligomers, the compounds of formula (R ~ R2N) COA, formula in which R ~ or R2, identical or different, represent hydrogen or a C-1 alkyl radical at C-10, preferably at C-1 to C-5, A represents (hydrogen, an alkyl radical in VS-1 to C-10, preferably in C-1 to C-5, or even the group R '~ R'2N with R '~, R'2, identical or different, representing hydrogen or an alkyl radical in C-1 to C-10, preferably to C-1 to C-5, cationic or amphoteric surfactants.
As regards the compounds of the (R ~ R2N) COA type, it is preferred to use the compounds comprising two amide functions. Preferably we use urea as co-additive.

WO 00/1688

9 PGT / FR99 / 02159 The cellulose nanofibrils falling within the scope of the present invention, sdnt from the drying of a dispersion of nanofibrils, preferably in the presence of a additive and possibly a co-additive.
Thus, the cellulose nanofibrils of the present invention can be used in dry dispersible form.
Another object of the present invention is the use of nanofibrils according to ~
the invention, if necessary in combination with an additive, and optionally a co-additive as an emulsifying and / or stabilizing agent in the fields of cosmetics, of food, concrete constructions, drilling fluids, polymerization radical like direct or reverse emulsion polymerization, in microemulsion, suspended, dispersed ...
The invention further relates to compositions in the fields of cosmetics, food, concrete constructions, drilling, or compositions based on polymer resulting from a radical polymerization, including nanofibrils according to the invention, if necessary in combination with a additive, and optionally a co-additive, as an emulsifying and / or stabilizing agent.
Concrete but nonlimiting examples of the invention will now be presented.
EXAMPLES
Ex ~ .m.1 ~ 1 ~ 1 This example relates to the preparation of cellulose nanofibrils (NFC) under mother suspension form, and in dry form comprising carboxymethylcellulose (CMC).
1. Preparation of the mother dispersion of nanofibrils The mother dispersion of cellulose nanofibrils is obtained in accordance with process described in example 20 of patent application EP 726 356; she understands 2.3% in cellulose nanofibrils and is prehomogenized with Ultra-Turrax at trlmn -1 min for 100 g of dispersion).
2. Preparation of dried nanofibrils comprising carboxymethylcellulose (CMC) The mother dispersion of cellulose nanofibrils is obtained in accordance with process described in example 20 of patent application EP 726 356; she understands 2.3% in cellulose microfibrils and is prehomogenized with Ultra-Turrax at rpm - 1 min for 100 g of dispersion).
The carboxymethylcellulose used has a degree of substitution equal at 1.2; medium viscosity (BLANOSE 12M8P product from AQUALON).
5 The CMC is dissolved in distilled water and then added to the.
(NFC) mother dispersion and the whole is stirred with a deflocculating paddle at 1000 trlmn for 30 min.
The amount of carboxymethylcellulose added is 30% relative to the weight of CMC.

10 The mixture is then poured into cups and dried in an oven ventilated at 40 ° C, up to a dry extract of 77%, controlled by dosing of using water an infrared thermobalance.
The dried mixture is then ground in a coffee grinder, then sieved through a sieve of 500 Nm.
The purpose of this example is to highlight the emulsifying power of cellulose nanofibrils (NFC).
1. Measurement of surface tension (eaulair) The surface tensions are measured with an automatic tensiometer of KREUSS (Type K 14) and a WILHELMY blade.
tni mother The cellulose nanofibrils are predispersed with moderate stirring in the water distilled in order to have a mass concentration of 0.28%. This dispersion is then stirred for 15 minutes at 1000 rpm, then homogenized under pressure atmospheric at Ultra Turrax for 2 minutes at 13,500 rpm.
A control of the quality of the water and the cleanliness of the material allows check the theoretical value of the surface tension of the distilled water from 71.1 mN / m to 23 ° C.
50 ml of dispersion are placed in a crystallizer of the tensiometer and left at rest for 30 minutes. The platform is then raised to immerse the blade.
The solution is allowed to equilibrate for 30 seconds. The value of the voltage surface is then determined (see Table I) II I t CMC

WO 00/16889 PC'T / FR99 / 02159

11 The dried cellulose nanofibrils of (Example 1 are predispersed under moderate agitation in distilled water in order to have a mass concentration 0.4%.
This dispersion is then stirred for 15 minutes at 1000 rpm, then homogenized at atmospheric pressure with Ultra Turrax for 2 minutes at trlmn.
The measurement of the surface tension is carried out as previously.
suoe ~ cielle voltage of the carboxvmeth 10 CMC dry powder (the references of which are given in Example 1) is predispersed with moderate stirring in distilled water to obtain a solution whose mass concentration is 0.12%. This dispersion is then restless for 15 minutes at 1000 rpm, then homogenized at atmospheric pressure at Ultra Turrax for 2 minutes at 13,500 rpm.
The surface tension measurement is carried out as above (cf.
Table 1).
Comparative Test: Measurement of the tension on ~ erfcielle of gum arabiq ~ g Gum arabic is predispersed with moderate stirring in distilled water 20 in order to obtain a solution whose mass concentration is 20%.
This dispersion is then stirred for 15 minutes at 1000 rpm, then homogenized at pressure atmospheric at Ultra Turrax for 2 minutes at 13,500 rpm.
The surface tension measurement is carried out as above (cf.
Table I).
2. Measurement of> interfacial tension (oil) The interfacial tensions are measured with a hanging drop tensiometer LAUDA TVT11 type.
No calibration is necessary with this device, only a verification prior cleanliness of the skin must be achieved.
The principle of manipulation is to form a drop of liquid 1 (water) containing the emulsifier in a continuous medium containing the second liquid 2 (oil) or vice versa (drop formed with the oil phase).
A (balance, the weight of the drop will be compensated by the interfacial tension of 35 liquid. An optical detection system measures the volume of the drop, the value can be related to interfacial tension.

12 Measurements are made in quasi-static mode, in order to leave the agent emulsifying time to migrate to the interface. Voltage values interfacial are determined after an equilibrium time of 30 minutes.
The results collated in Table I show that NFCs decrease by significantly the surface and interfacial tensions of very polarity different.
Table I
concentration Nature of oil Tensions in (mNlm) Agent emulsifying agent (30% body weight Interfacial emulsifier (weightweight oil) soybean oil 14.1 NFC without additive p, 2g% 38.8 (dispersion-mre) hexadcane 22 soybean oil 14 C 0.4% 40.2 NOT

70 30 hexadcan 21.7 soybean oil 20 CMC 0.12 71.5 (comparison) hexadcane 42 soybean oil 15 Gum arabic 2p% 47 (comparative) hexadcane 22.5 The results in Table I clearly show that NFCs have a power emulsifier (in terms of interfacial and surface tension) comparable to gum arabic, but at much lower concentrations than gum arabic.
Example 3 The purpose of this example is to highlight the stabilizing power of cellulose nanofbrilles (NFC).
For this, we prepared oil in water emulsions (hle) and measured the cut droplets by particle size and optical microscopy.

WO 00/16889 PG "f / FR99 / 02159

13 Preparation of emulsions The dispersions of NFC possibly additive are carried out in water distilled to the required concentration as in Example 2.
The adequate amount of soybean oil (RISSO brand) or n-hexadecane (from MERCK) is then added to the water phase (30% by mass compared to the phase aqueous) and the whole is prehomogenized with an Ultra type homogenizer "~
Turrax IKA T25 for 1 minute at 9500 rpm.
This prehomogenization is intended to guarantee a uniform passage in the Microfluidizer. In fact, we make 1 pass to the Microfluidizer M 110T at 500 bars the emulsions obtained are beautiful, homogeneous and stable over time.
Stable silicone oil emulsions of type 47 V 100 (Rhodorsil) are also prepared.
Characterization of emulsions The granulometry is determined by laser granulometry (HORIBA device of LA 910) and by optical microscopy (OLYMPUS BH- reference device 2).
The measurements are carried out immediately after emulsification, then at the regular interval after storage.
The values of the mean diameters given in Table 41 show that the use of NFC allows stable emulsions with particle sizes to be obtained relatively tight.
No stable emulsion could be obtained with CMC because the emulsions coalesce immediately after homogenization.

14 Table II: Evaluation of hexadcane oil and e m of so a, of silicon Emulsions Granulomtrie D * Index of (Irm) polydispersit I *

0.3% of NFCICMC

(Soya oil) initial time 12.1 1.1 after 1 month of storage 12.8 1.2 ambient temperature 0.5% of NFCICMC

(hexadcan) initial time 12.7 1.1 after 1 month of storage 13 1.1 ambient temperature 0.3% NFC / CMC

(silicone oil) initial time 21.3 1.2 after 1 month of storage 22 1,2 ambient temperature * D corresponds to the average diameter in Nm.
* I corresponds to the polydispersity index: the closer I is to 1 the more droplets are monodisperse.
Example 4 The purpose of this example is to show that NFCs in conjunction with CMC
as an emulsifying and stabilizing agent can lead to the production of a emulsion multiple water in oil in water (elhle), of relatively granulometry narrow, 50 microns and stable over time.
Composition soybean oil 30 city water 48 12% vinegar 13 sugar 6 NaCI 2.5 NFC / CMC 0.5 Procedure The sugar is then added with stirring at 500 rpm, then the NFCICMC with water. We door stirring at 1000 rpm and it is maintained for 15 min.
5 Then add the vinegar and salt and keep stirring for 3 minutes. ,.
The oil is then added and the whole is stirred for 3 minutes.
The whole is homogenized first for 1 minute at 9500 rpm at Ultra Turrax IKA T25, and then by passing to the Microfluidizer M 110T at 500 bars.
10 A beautiful, homogeneous and stable w / o emulsion over time is obtained.

Claims (22)

1. Use of essentially amorphous cellulose nanofibrils possessing a rate of crystallinity less than or equal to 50%, as an emulsifying agent and/or stabilizer of a dispersion. 2. Use according to claim 1, characterized in that the dispersion is a liquid-in-liquid emulsion. 3. Use according to claim 2, characterized in that the dispersion is a oil-in-water emulsion. 4. Use according to claim 2, characterized in that the dispersion is a water-in-oil emulsion. 5. Use according to claim 1, characterized in that the dispersion is a multiple emulsion consisting of three liquids. 6. Use according to claim 1, characterized in that the dispersion is a foam consisting of gas dispersed in a liquid or emulsion. 7. Use according to claim 1, characterized in that the dispersion is a emulsion or suspension of solid in liquid. 8. Use according to claim 1, characterized in that the dispersion is formed of a gas and two different liquids. 9. Use according to any one of claims 1 to 8, characterized in that the nanofibrils are present in an amount between 0.01 and 5% by weight per relative to the total weight of the dispersion. 10. Use according to one of claims 8 or 9, characterized in that them nanofibrils are present in an amount between 0.05 to 1% by weight, of preferably between 0.1 and 0.8% by weight relative to the total weight of the dispersion. 11. Use according to any one of claims 1 to 10, characterized in that the nanofibrils have a crystallinity rate of between 15 and 50%, of preferably less than 50%. 12. Use according to any one of claims 1 to 11, characterized in that the nanofibrils are derived from cells made up of at least 80% of walls primaries. 13. Use according to any one of claims 1 to 12, characterized in that the cellulose nanofibrils have at least 80% cell walls primaries. 14. Use according to any one of claims 1 to 13, characterized in that the nanofibrils are charged on the surface with carboxylic acids and acid polysaccharides, alone or as a mixture. 15. Use according to any one of claims 1 to 14, characterized in that the cellulose nanofibrils are associated with at least one organic compound polyhydroxylated (polyOH). 16. Use according to claim 15, characterized in that the compound organic polyhydroxylated (polyOH) is chosen from carbohydrates and their derivatives, and polyols. 17. Use according to one of claims 15 or 16, characterized in that that the polyhydroxy organic compound is associated with cellulose nanofibrils in a weight ratio (polyOH) x 100 / [(polyOH) + (NFC)] of between 5 and 50%, of preferably between 5 and 30%. 18. Use according to any one of claims 1 to 17, characterized in that the cellulose nanofibrils, and optionally the organic compound polyhydroxylated (polyOH), are associated with at least one co-additive chosen from:
the carboxylated cellulose having a lower or equal degree of substitution at 0.95, preferably carboxymethylated cellulose, osidic monomers or oligomers, the compounds of formula (R1R2N)COA, formula in which R1 or R2, identical or different, represent hydrogen or a C-1 alkyl radical to C-10, preferably C-1 to C-5, A represents hydrogen, an alkyl radical in VS-1 to C-10, preferably C-1 to C-5, or else the group R'1R'2N with R'1, R'2, identical or different, representing hydrogen or an alkyl radical in C-1 at C-10, preferably at C-1 to C-5, cationic or amphoteric surfactants.

these co-additives being used alone or as a mixture. 19. Use according to any one of claims 1 to 18, characterized in that the nanofibrils are employed in the form of an aqueous suspension. 20. Use according to any one of claims 1 to 18, characterized in that the nanofibrils are employed in dispersible dry form. 21. Use of nanofibrils according to any one of claims 1 at 14, the case optionally in combination with an additive according to any of the claims 15 to 17 and optionally a co-additive according to claim 18, as an agent emulsifier and/or stabilizer in the fields of cosmetics, food, buildings concrete, drilling fluids, free radical polymerization. 22. Composition in the fields of cosmetics, food, concrete constructions, drilling fluids, or compositions based on polymer resulting from a radical polymerization, comprising nanofibrils according to moon any of claims 1 to 14 where appropriate in combination with a additive according to any one of claims 15 to 17 and optionally a co-additive according to claim 18 as an emulsifying and/or stabilizing agent.