According to the invention, the derivative (S2) is an oligomer formed from a defined number of oses. Preferably according to the invention, the oligomer (S2) is chosen among ose dimers and ose trimers. More preferentially, it is chosen among dextrose, maltose, lactose, sucrose, maltoriose, maltotetraose, alpha-glucoheptonic acid, beta-glucoheptonic acid. Preferably, sucrose is used alone or in a mixture.

According to the invention, the derivative (S3) is a product resulting from the degradation of a saccharide generally obtained from a ketose that is degraded under defined conditions, leading to a chain rupture at the level of the ketone group. One or several carboxylic acids are generally obtained. Preferably according to the invention, the product (S3) is chosen among aldoses, synthetic monosaccharide derivatives and synthetic disaccharide derivatives. More preferentially, it is chosen among sorbitol, mannitol, gluconic acid, citric acid, isocitric acid, lactic acid, tartaric acid and salts of these acids. Gluconic, citric and tartaric acids are preferred, in particular gluconic acid used alone or in a mixture.

Particularly preferably according to the invention, the derivative (S) is chosen among sorbitol, mannitol, gluconic acid, citric acid, isocitric acid, lactic acid, tartaric acid, salts of these acids, dextrose, maltose, glucose, a mixture of glucose and of maltose, lactose, sucrose, maltoriose, maltotetraose, alpha-glucoheptonic acid, beta-glucoheptonic acid, salts of these acids and combinations of these derivatives.

These various derivatives (S) are generally commercially-available products, for example in crystalline form or in syrup form, such as glucose syrup or corn syrup.

According to the invention, the respective amounts of derivative (S) and of polymer (P) can vary quite significantly. Preferably according to the invention, the (S/P) ratio of the dry weight amounts of derivative (S) and of polymer (P) ranges from 0.1 to 10 or from 0.2 to 5 or from 0.3 to 5. More preferably, this ratio ranges from 0.5 to 4 or from 0.6 to 3. In addition to a dispersing agent, the invention also relates to an aqueous composition that comprises at least such a dispersing agent and a mineral material. Thus, the invention provides an aqueous composition comprising:

- (a) at least one dispersing agent according to the invention;
- (b) at least one mineral material in particle form.

Many mineral materials can be suitable for the composition according to the invention, in particular according to the nature or according to the form of the mineral material. Preferably, the particles of mineral material have an average diameter of less than 500 μm, less than 200 μm or less than 100 μm or less than 50 μm or even an average diameter ranging from 0.05 μm to 50 μm or an average diameter of less than 10 μm, preferably less than 5 μm or less than 2 μm, also preferentially less than 1 μm or less than 0.5 μm.

According to the invention, a single mineral material (a) or two or three mineral materials (a) are used. Preferably, a single mineral material or two mineral materials are used. Advantageously according to the invention, the mineral material (a) is of synthetic or natural origin. Preferably, it is chosen among the alkaline-earth metal carbonates, preferably calcium carbonate (natural calcium carbonate or precipitated calcium carbonate), strontium carbonate, magnesium carbonate, barium carbonate, dolomite, kaolin, calcined kaolin, titanium dioxide, iron oxide, talcum, calcium sulphate, barium sulphate, silicas, mica, zinc oxide.

More preferentially, it is chosen among calcium carbonate (natural calcium carbonate or precipitated calcium carbonate), titanium oxide, kaolin and calcined kaolin.

In addition to a dispersing agent according to the invention and a mineral material, the composition according to the invention may comprise other elements, in particular according to the technical field in which this composition is used.

Thus, the aqueous composition according to the invention may also comprise at least one bonding agent (c) of natural or synthetic origin. According to the invention, the bonding agent (c) can be a natural bonding agent such as starch, carboxymethyl cellulose (CMC), hydroxyethyl celluloses, polyvinyl alcohol (PV-OH), casein, proteins, alginates.

According to the invention, the bonding agent (c) can also be a synthetic bonding agent such as latex, preferably chosen among a styrene-butadiene polymer, a styrene-acrylic polymer, a styrene-acetate polymer, more preferentially a styrene-butadiene polymer.

The aqueous composition according to the invention may also comprise at least one thickening agent (d) of natural or synthetic origin. It is preferably chosen among a polymeric emulsion, a HASE polymer, an ASE polymer, a HEUR polymer, a polyurethane polymer, a steric thickening polymer, a polyacrylamide polymer, CMC, a CMC derivative and combinations thereof.

The proportions of the various elements of the aqueous composition according to the invention may vary significantly, in particular according to the technical field in which this composition is used.

Preferably, the aqueous composition according to the invention comprises:

- from 0.02 to 2% by dry mass of dispersing agent (a),
- from 30 to 75% by dry mass of mineral material (b),
- from 2 to 25% by dry mass of bonding agent (c),
- from 0.01 to 2% by dry mass of thickening agent (d) and
- from 22.97 to 42.98% by mass of water.

When used, the aqueous composition according to the invention can be used after dilution, in particular after dilution with water.

More preferably, the aqueous composition according to the invention is a paper coating colour composition.

The aqueous composition according to the invention can also comprise at least one admixture, in particular at least one admixture chosen among dispersing agents, anti-foaming agents, biocides, colouring agents, lubricants and optical brighteners.

The dispersing agent according to the invention is suitable for many uses. Preferably, the dispersing agent according to the invention is used in the preparation of an aqueous composition, preferably in the preparation of an aqueous composition according to the invention.

Thus, the invention also relates to the use of a dispersing agent according to the invention that comprises the addition of the dispersing agent in an aqueous suspension of at least one mineral material in particle form. This use according to the invention may also comprise the addition of at least one mineral material in particle form in an aqueous composition comprising at least one dispersing agent according to the invention.

The invention also relates to the use of at least one dispersing agent according to the invention in the preparation of an aqueous composition chosen among a paper coating colour composition, preferably for the preparation of a primary paper coating layer (pre-coat) or a final paper coating layer (top coat); a coating composition, preferably paint or varnish; an ink composition, preferably an ink composition for an inkjet printer; a care composition, preferably a body or hair care composition; a soil amendment composition. Preferably, this use relates to the preparation of a paper coating colour composition or a coating composition.

Moreover, the invention also provides a method for controlling the rheology of an aqueous composition comprising at least one polymer (P) defined according to the invention by adding to the composition at least one derivative (S) chosen among:

- an ose (S1) comprising from 3 to 8 carbon atoms;
- an ose oligomer (S2) comprising from 1 to 10 ose units;
- a product (S3) resulting from the degradation of a saccharide.

Preferably for this method according to the invention, the (S/P) ratio of the dry weight amounts of derivative (S) and of polymer (P) ranges from 0.1 to 10 or from 0.2 to 5 or from 0.3 to 5. More preferentially, it ranges from 0.5 to 4 or from 0.6 to 3.

More preferably according to the invention for this method according to the invention, the composition comprises at least one ingredient chosen among:

- a mineral material in particle form, preferably a material defined according to the invention;
- a bonding agent, preferably a bonding agent (c) defined according to the invention;
- a thickening agent, preferably a thickening agent (d) defined according to the invention.

The following examples illustrate the various aspects of the invention.

EXAMPLES
Preparation of the Polymers Used According to the Invention and of Comparative Polymers

Polymer (P1)

In a 1 L reactor equipped with mechanical stirring, oil bath heating and peristaltic pumps, weigh: 209.7 g of water, 0.08 g of iron sulphate heptahydrate and 0.011 g of copper sulphate pentahydrate. The mixture is then heated to 95° C. and, using the peristaltic pumps, 302.5 g of acrylic acid and 13 g of water, 25.6 g of sodium hypophosphite monohydrate dissolved in 29 g of water, 20.46 g of hydrogen peroxide 130V diluted with 25 g of water are added in 120 minutes. This is then cooked for 60 minutes at 95° C.

The mixture is then cooled, neutralised with 50% sodium hydroxide in water to pH 8.5 and diluted to obtain a dry solids content of 40%. The polymer (P1) sodium polyacrylate with a Mw of 4,400 g/mol is then obtained.

Polymer (P2)

In a 1 L reactor equipped with mechanical stirring, oil bath heating and peristaltic pumps, weigh: 158 g of water, 0.014 g of iron sulphate heptahydrate. The mixture is then heated to 80° C. and, using the peristaltic pumps, the following reagents are simultaneously added while maintaining the temperature at 81+/−1° C.: 271 g of acrylic acid in 210 min, 3.3 g of sodium persulphate dissolved in 44 g of water in 210 min and 114.46 g of a sodium bisulphite solution diluted to 40% by weight in water in 180 min. This is then cooked for 60 min at 80° C. It is then treated with 4.5 g of hydrogen peroxide at 130 V and cooked again for 60 min at 80° C.

The mixture is then cooled, neutralised with 50% sodium hydroxide in water to pH 8.5 and diluted to obtain a dry solids content of 40%. The polymer (P2) sodium polyacrylate with a Mw 2,800 of g/mol is then obtained.

Polymer (P3)

From itaconic acid partially neutralised with sodium hydroxide added slowly, under stirring and at a controlled temperature, then polymerised by heating in water and under stirring in the presence of sodium hypophosphite and of hydrogen peroxide, and finally partially decarboxylated by heating under reflux in water, a polymeric solution (P3) of partially decarboxylated sodium polyitaconate with a concentration of 40% by weight of polymer and a pH of 9 is prepared (method described in the examples in document WO 2015-100412).

The polymer (P3) with a Mw of 2,160 g/mol is obtained.

Polymer (P4)

In a 1 L reactor equipped with mechanical stirring, oil bath heating and peristaltic pumps, weigh: 245 g of water, 0.13 g of iron sulphate heptahydrate and 0.02 g of copper sulphate pentahydrate. The mixture is then heated to 95° C. and, using three separate pumps, a mixture of 284 g of acrylic acid and of 180 g of hydroxypropyl acrylate, 37 g of 130 V hydrogen peroxide diluted with 34 g of water and 96 g of a 50% sodium hypophosphite solution are simultaneously added in 120 minutes. This is then cooked for 60 minutes at 95° C.

The mixture is then cooled, neutralised with a 28° ammonia solution to pH 7 and diluted to obtain a dry solids content of 44%. The polymer (P4) with a Mw of 2,800 g/mol is then obtained.

Polymer (P5)

In a 1 L reactor equipped with mechanical stirring, oil bath heating and peristaltic pumps, weigh: 200 g of isopropanol and 1.7 g of AZDN. The mixture is then heated under reflux to about 80° C. and 200 g of acrylic acid and 81 g of butyl acrylate are added in 120 minutes using the peristaltic pumps. This is then cooked for 60 minutes under reflux. The isopropanol is then distilled and it is gradually replaced with water during distillation.

The mixture is then cooled, neutralised with a 50% potassium hydroxide solution in water to pH 8 and diluted to obtain a dry solids content of 40%. The polymer (P5) with a Mw of 9,000 g/mol is then obtained.

Polymer (P6)

In a 1 L reactor equipped with mechanical stirring, oil bath heating and peristaltic pumps, weigh 260 g of water, then heat to 65° C. and simultaneously add, in 180 min using three separate pumps: a mixture of 50 g of acrylic acid and 343 g of a poly(ethylene glycol-co-propylene glycol) macromonomer methacrylate with a molecular mass of 3,000 g/mol (corresponding on average to 46 units of ethylene oxide and 15 units of propylene oxide, randomly distributed) and ending by a hydroxyl group, 3.6 g of ammonium persulphate dissolved with 80 g of water and 4.5 g of 1,8-dimercapto-3,6-dioxaoctane (DMDO). This is then cooked for 60 minutes while gradually adding a solution of 1 g of sodium persulphate dissolved in 10 g of water.

The mixture is then cooled, neutralised with a 50% sodium hydroxide solution in water to pH 4 and diluted to obtain a dry solids content of 40%. The polymer (P6) with a Mw of 38,000 g/mol is then obtained.

Polymer (P7)

In a 2 L reactor equipped with mechanical stirring, oil bath heating and peristaltic pumps, weigh: 230 g of isopropanol, 230 g of water, 0.005 g of iron sulphate heptahydrate and 0.11 g of hydoxylamine sulphate. The mixture is then heated under reflux to about 80° C. and, using three peristaltic pumps, a mixture comprising 296.8 g of acrylic acid, 164.2 g of an aqueous solution at 50% by weight of sodium 2-acrylamido-2-methylpropanesulphonate is added in 120 minutes, along with 12 g of 130 V hydrogen peroxide diluted in 50 g of water and 3.3 g of hydroxylamine sulphate dissolved in 70 g of water. This is then cooked for 60 minutes under reflux. The isopropanol is then distilled and it is gradually replaced with water during distillation. The mixture is then cooled, neutralised with sodium hydroxide at 50% in water to pH 4 and diluted to obtain a dry solids content of 50%. A polymer (P7) of with a Mw of 5,000 g/mol is then obtained.

Preparation of Dispersing Agents According to the Invention and of Comparative Dispersing Agents

A dispersing agent (D1) according to the invention is prepared by mixing the polymer (P1) with the derivative (S1). The polymer (P1) is weighed in a beaker and then the derivative (S1) and water are added, under stirring using a VMI turbine motor 30 at 1,000 rpm. The amounts used are shown in Table 1.

Similarly, other dispersing agents according to the invention are prepared. The following derivatives (S) were used:

- S1-1: glucose syrup at 80% by weight of solids content (CSweet M01658, Cargill),
- S1-2: glucose syrup at 85% by weight of solids content (74/968, Roquette) and
- S1-3: glucose syrup at 91% by weight of solids content (4779, Roquette).

TABLE 1

S3-1: gluconic acid at 48% by

weight of solids content

(EMF1240, Jungbunzlauer)
Polymer
Amount
Derivative
Amount
(S)/(P)
Amount

Dispersing agent
(P)
of (P)
(S)
of (S)
ratio
of water

D1
P1
142.9
S1-1
50
40/60
45

D2
P1
95.2
S1-1
75
60/40
68

D3
P1
142.9
S1-2
47.1
40/60
48

D4
P1
95.2
S1-2
70.6
60/40
72

D5
P1
142.9
S3-1
80
40/60
15

D6
P1
95.2
S3-1
120
60/40
23

D7
P1
142.9
S1-3
43.8
40/60
51

D8
P1
95.2
S1-3
65.6
60/40
77

D9
P2
142.9
S1-1
50
40/60
45

D10
P3
150
S1-1
50
40/60
50

D11
P4
93
S1-2
75
60/40
65

D12
P5
125
S1-2
58.8
50/50
66

D13
P6
100
S1-2
70.6
60/40
79

D14
P7
100
S1-2
58.8
50/50
41

The final solids content of each dispersing agent is controlled using a CEM microwave scale at 110° C. until a solids content variation of less than 0.1% by weight is obtained after 10 seconds. The solids content of the agents according to the invention is 42% by weight, with the exception of dispersing agents D12, D13 and D14 which have, respectively, a solids content of 40% by weight, 40% by weight and 44% by weight.

Preparation of Aqueous Compositions of Mineral Materials Comprising the Dispersing Agents According to the Invention or the Comparative Dispersing Agents

An aqueous composition according to the invention (C1) is prepared.

The dispersing agent (D2) according to the invention is weighed in a beaker, then water is added followed by a mineral pigment (PM1) while stirring until 2,500 rpm using a VMI stirrer equipped with a 65 mm turbine.

Lastly, sodium hydroxide at 12.5% by weight is added in water until the pH is controlled and stirring is maintained for 20 min. The solids content of the composition is then measured. The respective amounts (g) and content in dispersing agent (% by dry weight relative to the amount of dry pigment) of the different ingredients and the characteristics of the prepared compositions are shown in tables 2 and 3.

Similarly, aqueous compositions (C2) to (C36) according to the invention are prepared as well as comparative compositions (CC1) to (CC14) with no derivative (S) in the dispersing agent used but only a comparative polymer. The pH of the compositions is adjusted to 8.5, with the exception of the pH of aqueous compositions (C33), (C34), (C35) and (C36) according to the invention which is respectively 7, 7, 9 and 9, and of comparative compositions (CC12), (CC13) and (CC14) which is respectively 9, 7 and 7. Dispersing agents (D1) to (D14) according to the invention were used. The following mineral pigments were used:

- PM1: kaolin (Capim DG, Imerys),
- PM2: kaolin (Amazon plus Lump, Kamin),
- PM3: calcium carbonate (Violet label, Omya),
- PM4: precipitated calcium carbonate (SOCAL P3, Solvay),
- PM5: kaolin (Speswhite, Imerys),
- PM6: titanium dioxide (RHD2, Elementis),
- PM7: titanium dioxide (RCL 722, Cristal) and
- PM8: calcined kaolin (Hubertex, Kamin).

The viscosity (mPa·s) of the aqueous suspensions prepared using a Brookfield RVI viscometer is measured at 100 rpm and at 25° C. The results are shown in tables 2 and 3.