OSIDIC DISPERSING AGENT

Abstract

The invention relates to the field of dispersing agents for an aqueous composition, in particular for dispersing a mineral material in the form of particles. The dispersing agent according to the invention comprises a dispersing polymer combined with an osidic derivative or a derivative of saccharide origin. The invention also relates to an aqueous composition comprising said dispersing agent and a mineral material in the form of particles, and to the use of said agent or composition.

Claims

1. An aqueous dispersing agent, comprising: at least one polymer (P) prepared by at least one radical polymerisation reaction, at a temperature greater than 50° C., of at least one anionic monomer (M1) comprising at least one polymerisable olefinic unsaturation and at least one carboxylic acid group or a salt thereof, in the presence of at least one radical-generating compound selected from the group consisting of hydrogen peroxide, benzoyl peroxide, acetyl peroxide, lauryl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, ammonium persulphate, an alkali metal persulphate, an azo compound, a combination thereof and associations with an ion selected from the group consisting of Fe.sup.II, Fe.sup.III, Cu.sup.I, Cu.sup.II and a combination thereof; and at least one derivative (S) selected from the group consisting of: an ose (S1) comprising from 3 to 8 carbon atoms; an ose oligomer (S2) comprising from 1 to 10 ose units; and a product (S3) resulting from degradation of a saccharide.

2. The aqueous dispersing agent according to claim 1, wherein: the polymerisation reaction is also carried out in the presence of at least one compound comprising phosphorus in an oxidation I state; the polymerisation reaction is also carried out in the presence of at least one compound comprising a bisulphite ion; the polymerisation reaction is carried out in the presence of at least one compound comprising phosphorus in an oxidation III state; the polymerisation reaction is also carried out in the presence of between 0.05 and 5% by weight, relative to a total amount of monomers, of at least one compound selected from the group consisting of a xanthate derivative, a mercaptan compound and a compound of formula (I): ##STR00003## wherein: X independently represents H, Na or K, R independently represents a C.sub.1-C.sub.5-alkyl group; the polymerisation reaction is also carried out in the presence of at least one reducing compound; the polymerisation reaction is carried out at atmospheric pressure and at a temperature ranging from 50 to 98° C.; at a pressure greater than atmospheric pressure and at a temperature greater than 100° C.; the polymerisation reaction is carried out in water, in a solvent, alone or in a mixture with water; the polymer (P) is completely or partially neutralised, optionally at the end of the polymerisation reaction; optionally by means of at least one derivative selected from the group consisting of an alkali metal, an alkaline earth metal, an amine derivative, ammoniac, and ammonia; or the polymerisation reaction uses, relative to a total amount by weight of monomers: 100% by weight of anionic monomer (M1) or from 50% to 99.5% by weight of anionic monomer (M1) and from 0.5% to 50% by weight of at least one other monomer.

3. The aqueous dispersing agent according to claim 1, wherein the anionic monomer (M1) comprising at least one polymerisable olefinic unsaturation comprises one or two carboxylic acid groups.

4. The aqueous dispersing agent according to claim 1, wherein the polymerisation reaction also uses at least one other monomer selected from the group consisting of: another anionic monomer (M1); at least one non-ionic monomer (M2) comprising at least one polymerisable olefinic unsaturation; at least one monomer (M3) selected from the group consisting of 2-acrylamido-2-methylpropanesulphonic acid, a 2-acrylamido-2-methylpropanesulphonic acid salt, 2-(methacryloyloxy)ethanesulphonic acid, a 2-(methacryloyloxy)ethanesulphonic acid salt, sodium methallyl sulphonate, styrene sulphonate, hydroxyethyl-acrylate phosphate, hydroxypropyl-acrylate phosphate, hydroxyethyl methacrylate phosphate, and hydroxypropyl-methacrylate phosphate; at least one monomer (M4) of formula (II): ##STR00004## wherein: R.sup.1 and R.sup.2, identical or different, independently represent H or CH.sub.3, L.sup.1 independently represents a group selected from the group consisting of C(O), CH.sub.2, CH.sub.2—CH.sub.2 and O—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2, L.sup.2 independently represents a group chosen among selected from the group consisting of (CH.sub.2—CH.sub.2O).sub.x, (CH.sub.2CH(CH.sub.3)O).sub.y, (CH(CH.sub.3)CH.sub.2O).sub.z and combinations a combination thereof and x, y and z independently represent an integer or decimal in a range from 0 to 150 and a sum of x+y+z is in a range from 10 to 150; at least one compound (M5) of formula (III):
R.sup.1(EO).sub.m(PO)—R.sup.2   (III) wherein: m and n, independently represent 0 or an integer or decimal less than 150, m or n being different from 0, EO represents a CH.sub.2CH.sub.2O group, PO independently represents a group selected from the group consisting of CH(CH.sub.3)CH.sub.2O and CH.sub.2CH(CH.sub.3)O, R.sup.1 represents a group comprising at least one polymerisable olefinic unsaturation, R.sup.2 represents a straight, branched or cyclical, saturated, unsaturated or aromatic hydrocarbon group comprising from 6 to 40 carbon atoms; at least one monomer (M6) selected from the group consisting of: polyalkylene glycol acrylate, polyalkylene glycol methacrylate, allyl polyalkylene glycol, methallyl polyalkylene glycol, 3-methyl-3-buten-1-ylpolyalkylene glycol, polyalkylene glycol acrylate phosphate, polyalkylene glycol methacrylate phosphate, allyl polyalkylene glycol phosphate, methallyl polyalkylene glycol phosphate, and 3-methyl-3-buten-1-ylpolyalkylene glycol phosphate, and least one monomer (M7) selected from the group consisting of a cross-linking compound and a monomer comprising at least two olefinic unsaturations.

5. The aqueous dispersing agent according to claim 1, wherein the derivative (S) is selected from the group consisting of: an ose (S1) selected from the group consisting of trioses (oses comprising 3 carbon atoms), tetroses (oses comprising 4 carbon atoms), pentoses (oses comprising 5 carbon atoms), hexoses and deoxyhexoses (oses comprising 6 carbon atoms), heptoses (oses comprising 7 carbon atoms), and octoses (oses comprising 8 carbon atoms); an oligomer (S2) selected from the group consisting of ose dimers, and ose trimers; a product (S3) selected from the group consisting of aldoses, synthetic monosaccharide derivatives, and synthetic disaccharide derivatives.

6. The aqueous dispersing agent according to claim 1, wherein the derivative (S) is selected from the group consisting of 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, a salt of an acid thereof, and a combination of a derivative thereof.

7. The agent according to claim 1, wherein an (S/P) ratio of dry weight amounts of derivative (S) and of polymer (P) ranges from 0.1 to 10.

8. An aqueous composition, comprising: (a) the aqueous dispersing agent according to claim 1; (b) a mineral material in particle form.

9. The aqueous composition according to claim 8, wherein: the particles of mineral material have an average diameter of less than 500 μm; or a single mineral material (a) or two or three mineral materials (a) are used; or the mineral material (a) is of synthetic or natural origin.

10. The aqueous composition according to claim 8, further comprising: a bonding agent (c) of natural or synthetic origin; or a thickening agent (d) of natural or synthetic origin.

11. The aqueous composition according to claim 8, comprising: from 0.02 to 2% by dry mass of the aqueous dispersing agent (a), from 30 to 75% by dry mass of the mineral material (b), from 2 to 25% by dry mass of the bonding agent (c), from 0.01 to 2% by dry mass of the thickening agent (d) and from 22.97 to 42.98% by mass of water.

12. The aqueous composition according to claim 8, further comprising at least one admixture.

13. A method for preparing an aqueous composition the method comprising: adding the aqueous dispersing agent according to claim 1 in an aqueous suspension of at least one mineral material in particle form or adding at least one mineral material in particle form in an aqueous composition comprising the aqueous dispersing agent.

14. A paper coating colour composition, comprising the aqueous dispersing agent according to claim 1.

15. A method for controlling a rheology of an aqueous composition comprising at least one polymer (P) the method comprising: adding to the aqueous composition at least one derivative (S) selected from the group consisting of: an ose (S1) comprising from 3 to 8 carbon atoms; an ose oligomer (S2) comprising from 1 to 10 ose units; and a product (S3) resulting from the degradation of a saccharide, wherein the at least one polymer (P) is prepared by at least one radical polymerisation reaction, at a temperature greater than 50° C., of at least one anionic monomer (M1) comprising at least one polymerisable olefinic unsaturation and at least one carboxylic acid group or a salt thereof, in the presence of at least one radical-generating compound selected from the group consisting of hydrogen peroxide, benzoyl peroxide, acetyl peroxide, lauryl Peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, ammonium persulphate, an alkali metal persulphate, an azo compound, a combination thereof and associations with an ion selected from the group consisting of Fe.sup.II, Fe.sup.III, Cu.sup.I, Cu.sup.II and a combination thereof.

16. The method according to claim 15, wherein an (S/P) ratio of the dry weight amounts of derivative (S) and of polymer (P) ranges from 0.1 to 10.

17. The method according to claim 15, wherein the composition comprises at least one ingredient selected from the group consisting of: a mineral material in particle form; a bonding agent; a thickening agent.

Description

EXAMPLES

[0117] Preparation of the Polymers Used According to the Invention and of Comparative Polymers

[0118] Polymer (P1)

[0119] 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.

[0120] 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.

[0121] Polymer (P2)

[0122] 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.

[0123] 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.

[0124] Polymer (P3)

[0125] 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).

[0126] The polymer (P3) with a Mw of 2,160 g/mol is obtained.

[0127] Polymer (P4)

[0128] 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.

[0129] 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.

[0130] Polymer (P5)

[0131] 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.

[0132] 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.

[0133] Polymer (P6)

[0134] 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.

[0135] 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.

[0136] Polymer (P7)

[0137] 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.

[0138] Preparation of Dispersing Agents According to the Invention and of Comparative Dispersing Agents

[0139] 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.

[0140] Similarly, other dispersing agents according to the invention are prepared. The following derivatives (S) were used: [0141] S1-1: glucose syrup at 80% by weight of solids content (CSweet M01658, Cargill), [0142] S1-2: glucose syrup at 85% by weight of solids content (74/968, Roquette) and [0143] S1-3: glucose syrup at 91% by weight of solids content (4779, Roquette).

TABLE-US-00001 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

[0144] 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.

[0145] Preparation of Aqueous Compositions of Mineral Materials Comprising the Dispersing Agents According to the Invention or the Comparative Dispersing Agents

[0146] An aqueous composition according to the invention (C1) is prepared.

[0147] 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.

[0148] 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.

[0149] 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: [0150] PM1: kaolin (Capim DG, Imerys), [0151] PM2: kaolin (Amazon plus Lump, Kamin), [0152] PM3: calcium carbonate (Violet label, Omya), [0153] PM4: precipitated calcium carbonate (SOCAL P3, Solvay), [0154] PM5: kaolin (Speswhite, Imerys), [0155] PM6: titanium dioxide (RHD2, Elementis), [0156] PM7: titanium dioxide (RCL 722, Cristal) and [0157] PM8: calcined kaolin (Hubertex, Kamin).

[0158] The viscosity (mPa.Math.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.

TABLE-US-00002 TABLE 2 Dispersing Dispersing Mineral Dispersing agent - agent - Mineral pigment - Water - Composition agent Amount Content pigment Amount Amount Viscosity C1 D2 0.95 0.1 PM1 487 52.7 670 C2 D4 0.95 0.1 PM1 487 52.7 630 C3 D6 0.95 0.1 PM1 487 52.7 660 C4 D8 0.95 0.1 PM1 487 52.7 640 CC1 0 0.95 0.1 PM1 487 52.7 900 C5 D10 1.5 0.15 PM1 487 52.7 850 CC2 0 1.5 0.15 PM1 487 52.7 930 C6 D1 1.9 0.2 PM1 487 52.7 980 C7 D2 1.9 0.2 PM1 487 52.7 600 C8 D3 1.9 0.2 PM1 487 52.7 760 C9 D4 1.9 0.2 PM1 487 52.7 640 C10 D5 1.9 0.2 PM1 487 52.7 1,000 C11 D6 1.9 0.2 PM1 487 52.7 780 C12 D7 1.9 0.2 PM1 487 52.7 690 C13 D8 1.9 0.2 PM1 487 52.7 780 C14 D10 1.9 0.2 PM1 487 52.7 880 CC3 0 1.9 0.2 PM1 487 52.7 1,350 C15 D1 2.38 0.25 PM1 487 52.7 1,120 C16 D2 2.38 0.25 PM1 487 52.7 620 C17 D3 2.38 0.25 PM1 487 52.7 900 C18 D4 2.38 0.25 PM1 487 52.7 680 C19 D5 2.38 0.25 PM1 487 52.7 1,140 C20 D6 2.38 0.25 PM1 487 52.7 860 C21 D7 2.38 0.25 PM1 487 52.7 730 C22 D8 2.38 0.25 PM1 487 52.7 860 CC4 0 2.38 0.25 PM1 487 52.7 1,700

TABLE-US-00003 TABLE 3 Dispersing Mineral Dispersing Dispersing agent - Mineral pigment - agent - Water - Composition agent Amount pigment Amount Content Amount Viscosity C23 D12 2.38 410.3 PM2 0.25 114.3 195 C24 D9 2.38 410.3 PM2 0.25 114.3 195 CC5 0 2.38 410.3 PM2 0.25 114.3 230 C25 D3 0.95 PM3 407.7 0.1 112 100 CC6 0 0.95 PM3 407.7 0.1 112 110 C26 D1 1.43 PM3 407.7 0.15 112 100 C27 D3 1.43 PM3 407.7 0.15 112 100 CC7 0 1.43 PM3 407.7 0.15 112 150 C28 D3 3.33 PM4 400 0.35 187 240 CC8 0 3.33 PM4 400 0.35 187 260 C29 D13 6 PM4 400 0.6 182.2 720 CC9 0 6 PM4 400 0.6 182.2 830 C30 D14 6.36 PM4 400 0.7 186 304 CC10 0 6.36 PM4 400 0.7 186 380 C31 D1 1.9 PM5 487 0.2 52.7 460 C32 D6 1.9 PM5 487 0.2 52.7 480 CC11 0 1.9 PM5 487 0.2 52.7 530 C33 D12 5 PM6 400 0.5 131 80 CC12 0 5 PM6 400 0.5 131 214 C34 D11 2 PM7 405.7 0.5 125.75 140 CC13 0 2 PM7 405.7 0.5 125.75 180

[0159] It was found that the compositions according to the invention have a lower viscosity than the comparative compositions, though they contain a smaller amount of polymer. Moreover, a dilating effect was evaluated by measuring the shear rate (s.sup.−1) at 25° C. of the aqueous suspensions prepared, using a coaxial Thermofisher RS600 rheometer whose spindle has a CC27 DG Ti geometry while increasing the speed (s.sup.−1) of the spindle until this spindle is blocked. The results are shown in Table 4.

TABLE-US-00004 TABLE 4 Dispersing Mineral Dispersing Dispersing agent - Mineral pigment - agent - Water - Composition agent Amount pigment Amount Content Amount Shear rate C35 D3 2 PM8 413.2 0.5 385.8 870 C36 D4 2 PM8 413.2 0.5 385.8 1,180 CC14 0 2 PM8 413.2 0.5 385.8 800

[0160] It was found that the dilating effect of the compositions according to the invention is lower than that of the comparative composition. In fact, the compositions according to the invention make it possible to achieve a higher shear rate by the time the spindle blocks.