Thickening anionic copolymer

Abstract

The invention relates to a copolymer obtained by polymerisation reaction of at least three comonomers: a first anionic monomer, a second monomer comprising an olefin unsaturation, and a third monomer comprising a hydrophobic group. The invention likewise relates to the use of said copolymer as a thickening agent, in particular in aqueous suspensions of mineral particles with high solids content. The copolymer according to the invention makes it possible to improve the compromise between viscosity with high shear gradient and viscosity with low shear gradient, while also improving water retention inside the suspension.

Claims

1. A copolymer (P1), obtained by a polymerization reaction of a monomer composition consisting of: (a1) 5% to 30% by weight, based on the total amount by weight of monomers, at least one anionic monomer selected from the group consisting of acrylic acid and methacrylic acid, (b1) 65% to 90% by weight, based on the total amount by weight of monomers, at least one monomer of formula (I): ##STR00003## in which: R.sup.1 and R.sup.2, which are identical or different, independently represent H or CH.sub.3, L.sup.1 independently represents a group chosen from C(O), CH.sub.2 and CH.sub.2—CH.sub.2, L.sup.2 independently represents a group chosen from (CH.sub.2—CH.sub.2O).sub.x, (CH(CH.sub.3)CH.sub.2O).sub.y and combinations thereof, and x and y, which are identical or different, independently represent 0 or an integer or decimal number between 0.1 and 150, wherein x is strictly greater than y and the sum x+y is between 10 and 150, and (c1) 0.5% to 30% by weight, based on the total amount by weight of monomers, at least one monomer of formula (II): ##STR00004## in which: R.sup.3 independently represents a functional group derived from a compound selected from the group consisting of acrylate, methacrylate, acrylurethane and methacrylurethane, R.sup.4 independently represents a saturated, linear hydrocarbon group comprising from 6 to 40 carbon atoms, an unsaturated linear hydrocarbon group comprising from 6 to 40 carbon atoms, a saturated branched hydrocarbon group comprising from 6 to 40 carbon atoms, an unsaturated branched hydrocarbon group comprising from 6 to 40 carbon atoms, a saturated cyclic hydrocarbon group comprising from 6 to 40 carbon atoms, an unsaturated cyclic hydrocarbon group comprising from 6 to 40 carbon atoms, or an aromatic hydrocarbon group comprising from 6 to 40 carbon atoms, L.sup.3 independently represents a group chosen from (OCH.sub.2—CH.sub.2).sub.m, (OCH(CH.sub.3)CH.sub.2).sub.n and combinations thereof, and m and n, which are identical or different, independently represent 0 or an integer or decimal number between 0.1 and 150, wherein m is strictly greater than n and the sum m+n is between 10 and 150, and (d1) optionally 0.1% to 7% by weight, based on the total amount by weight of monomers, of at least one additional monomer selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl methacrylate, sodium methallylsulfonate, and styrenesulfonate, or a salt thereof, and (e1) optionally 0.01% to 5% by weight, based on the total amount by weight of monomers, of at least one crosslinking monomer or at least one monomer comprising at least two olefinic unsaturations.

2. The copolymer (P1) of claim 1, wherein at least two different anionic monomers (a1) are present in said composition.

3. The copolymer (P1) of claim 1, wherein (a1) is present in an amount of 6% to 25% by weight based on a total amount by weight of monomers.

4. The copolymer (P1) of claim 1, wherein: R.sup.1 represents H, or L.sup.1 represents a group chosen from C(O) and CH.sub.2, or L.sup.2 represents a group comprising (CH.sub.2—CH.sub.2O).sub.x and (CH(CH.sub.3)CH.sub.2O).sub.y, or x represents an integer or decimal number between 10 and 140, or y represents an integer or decimal number between 10 and 140 or x is strictly greater than y and the sum x+y is between 10 and 150.

5. The copolymer (P1) of claim 1, wherein: x represents an integer or decimal number between 15 and 140, y represents an integer or decimal number between 10 and 135 and x is strictly greater than y and the sum x+y is between 10 and 150, or wherein: x represents an integer or decimal number between 15 and 140 and y represents 0.

6. The copolymer (P1) of claim 1, wherein x represents an integer or decimal number between 15 and 80 and y represents an integer or decimal number between 10 and 65, or x represents an integer or decimal number between 15 and 80 and y represents 0.

7. The copolymer (P1) of claim 1, wherein (b1) is present in an amount of 75% to 90% by weight based on a total amount by weight of monomers.

8. The copolymer (P1) of claim 1, wherein at least two different monomers (c1) are present in said composition.

9. The copolymer (P1) of claim 1, wherein: R.sup.4 independently represents a linear or branched C.sub.6-C.sub.40 alkyl group, or L.sup.3 represents a (OCH.sub.2CH.sub.2), group, or m represents an integer or decimal number between 10 and 140, or n represents an integer or decimal number between 10 and 140, or m is strictly greater than n and the sum m+n is between 10 and 150.

10. The copolymer (P1) of claim 1, wherein: R.sup.4 independently represents a linear or branched C.sub.6-C.sub.40 alkyl group, L.sup.3 represents a (OCH.sub.2CH.sub.2).sub.mgroup, and m represents an integer or decimal number between 10 and 140.

11. The copolymer (P1) of claim 1, wherein (c1) is present in an amount of 1% to 25% by weight based on a total amount by weight of monomers.

12. The copolymer (P1) of claim 1, wherein (d1) is present.

13. The copolymer (P1) of claim 1, wherein the composition wherein (e1) is present.

14. A thickening agent, comprising at least one copolymer (P1) of claim 1 or at least one of: a composition (C1) comprising: the at least one copolymer (P1) and water, a composition (C2) comprising: the at least one copolymer (P1), water and at least one polymer HASE type (P2), a composition (C3) comprising: the at least one copolymer (P1), water and at least one ASE type polymer (P3), and a composition (C4) comprising: the at least one copolymer (P1), water, at least one HASE type polymer (P2) and at least one ASE type polymer (P3).

15. A method of preparing a coating composition, the method comprising combining the thickening agent of claim 14 with a pigment, binding agent, thickening agent, optical brightener, activating agent, or thickening copolymer or formulation.

Description

EXAMPLES

(1) All the reactions for the synthesis of copolymers described were carried out in a cylindrical glass reactor with a working volume of 1 litre equipped with a mechanical stirrer of anchor type and with an oil bath heating system. Stirring is maintained throughout the duration of the synthesis.

(2) A—Preparation and Characterization of Copolymers According to the Invention

Example A1

(3) An initial charge composed of 513.7 g of deionized water, 217 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 19.9 g of acrylic acid, 6.5 g of methacrylic acid and 24 g of a tristyrylphenol methacrylate monomer ethoxylated with 25 ethylene oxide units is introduced into the glass reactor.

(4) 1.0 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(5) 1.5 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(6) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(7) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.8 and is diluted with an amount of water sufficient to achieve a solids content of 28%.

Example A2

(8) An initial charge composed of 515 g of deionized water, 195.2 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 23.1 g of methacrylic acid and 24 g of an n-dodecanol methacrylate monomer ethoxylated with 23 ethylene oxide units is introduced into the glass reactor.

(9) 1.1 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(10) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(11) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(12) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.5 and is diluted with an amount of water sufficient to achieve a solids content of 25%.

Example A3

(13) An initial charge composed of 515 g of deionized water, 194.1 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 24.5 g of an oxo-dodecanol methacrylate monomer ethoxylated with 30 ethylene oxide units is introduced into the glass reactor.

(14) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(15) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(16) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(17) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 4.5 and is diluted with an amount of water sufficient to achieve a solids content of 28%.

Example A4

(18) An initial charge composed of 505 g of deionized water, 207.1 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 12.2 g of an oxo-dodecanol methacrylate monomer ethoxylated with 30 ethylene oxide units is introduced into the glass reactor.

(19) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(20) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(21) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(22) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 4.5 and is diluted with an amount of water sufficient to achieve a solids content of 30%.

Example A5

(23) An initial charge composed of 500 g of deionized water, 215.0 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 4.4 g of an oxo-dodecanol methacrylate monomer ethoxylated with 30 ethylene oxide units is introduced into the glass reactor.

(24) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(25) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(26) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(27) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 4.5 and is diluted with an amount of water sufficient to achieve a solids content of 30%.

Example A6

(28) An initial charge composed of 520 g of deionized water, 181.2 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 36.7 g of an oxo-dodecanol methacrylate monomer ethoxylated with 30 ethylene oxide units is introduced into the glass reactor.

(29) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(30) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(31) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(32) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 4.5 and is diluted with an amount of water sufficient to achieve a solids content of 28%.

Example A7

(33) An initial charge composed of 540 g of deionized water, 168.3 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 48.9 g of an oxo-dodecanol methacrylate monomer ethoxylated with 30 ethylene oxide units is introduced into the glass reactor.

(34) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(35) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(36) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(37) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.0 and is diluted with an amount of water sufficient to achieve a solids content of 28%.

Example A8

(38) An initial charge composed of 500 g of deionized water, 217.3 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 2.5 g of an oxo-dodecanol methacrylate monomer ethoxylated with 30 ethylene oxide units is introduced into the glass reactor.

(39) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(40) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(41) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(42) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.6 and is diluted with an amount of water sufficient to achieve a solids content of 30%.

Example A9

(43) An initial charge composed of 515 g of deionized water, 194.1 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 24.5 g of an n-dodecanol methacrylate monomer ethoxylated with 23 ethylene oxide units is introduced into the glass reactor.

(44) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(45) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(46) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(47) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.2 and is diluted with an amount of water sufficient to achieve a solids content of 30%.

Example A10

(48) An initial charge composed of 515 g of deionized water, 200 g of a poly(ethylene glycol) methacrylate macromonomer with a molecular weight of 5,000 g/mol (corresponding to approximately 110 ethylene oxide units), 24.5 g of acrylic acid and 24.5 g of an n-dodecanol methacrylate monomer ethoxylated with 23 ethylene oxide units is introduced into the glass reactor.

(49) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(50) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(51) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(52) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.2 and is diluted with an amount of water sufficient to achieve a solids content of 25%.

Example A11

(53) An initial charge composed of 515 g of deionized water, 194.1 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 24.5 g of an n-docosanol methacrylate monomer ethoxylated with 25 ethylene oxide units is introduced into the glass reactor.

(54) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(55) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(56) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(57) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 5.5 and is diluted with an amount of water sufficient to achieve a solids content of 25%.

Example A12

(58) An initial charge composed of 502 g of deionized water, 207.1 g of a poly(ethylene glycol-co-propylene glycol) methacrylate macromonomer with a molecular weight of 3,000 g/mol (corresponding on average to 46 ethylene oxide units and 15 propylene oxide units randomly distributed), 24.5 g of acrylic acid and 12.2 g of an n-dodecanol methacrylate monomer ethoxylated with 23 ethylene oxide units is introduced into the glass reactor.

(59) 0.6 g of 1,8-dimercapto-3,6-dioxaoctane are weighed in a first container of disposable syringe type.

(60) 0.85 g of ammonium persulfate are weighed in a second container of glass beaker type and are dissolved in 4.5 g of deionized water.

(61) The reactants of the first container and the second container are introduced into the polymerization reactor when the reaction medium present in the latter reaches 67° C. Cooking is then carried out for 2 hours while maintaining the reaction medium at 65° C.±1° C.

(62) At the end of the reaction, the combined mixture is neutralized with an amount of sodium hydroxide sufficient to achieve a pH of 4.6 and is diluted with an amount of water sufficient to achieve a solids content of 30%.

(63) Characterizations of the Polymers According to the Invention

(64) The solids content of the synthesized products is measured using a heat chamber at 110° C. 1 g of product is placed in the heat chamber for 1 h. The difference in weight before and after drying makes it possible to determine the solids content.

(65) The pH is measured at 25° C. with a pH meter of WTW trade mark equipped with a conventional electrode coupled to a temperature probe.

(66) The results obtained are presented in Table 1. The monomers employed are also defined in Table 1; their respective proportions by weight based on the total mass amount of monomers are shown therein. The monomers (a1) AA and MAA are respectively acrylic acid and methacrylic acid. The macromonomer (b1) is poly(ethylene glycol-co-propylene glycol) methacrylate (b1-1) with a molecular weight of 3,000 g/mol and the macromonomer (b1) is poly(ethylene glycol) methacrylate (b1-2) with a molecular weight of 5,000 g/mol. The different monomers (e1) are also defined.

(67) TABLE-US-00001 TABLE 1 (a1) (b1) Solids (amount) (amount) Viscosity content Example (%) (%) (c1) (amount) (%) (mPa .Math. s) (%) pH A1 AA (7.5) + b1-1 Tristyrylphenol 15,700 27.5 5.8 MAA (2.5) (84.5) methacrylate-25 EO (5.5) A2 MAA (11) b1-1 (84) n-Dodecanol 410 25.3 5.5 methacrylate-23 EO (5) A3 AA (10) b1-1 (80) Oxo-dodecanol 2,300 28 4.3 methacrylate-30 EO (10) A4 AA (10) b1-1 (85) Oxo-dodecanol 680 29.1 4.6 methacrylate-30 EO (5) A5 AA (10) b1-1 (88) Oxo-dodecanol 480 29.3 4.5 methacrylate-30 EO (2) A6 AA (10) b1-1 (75) Oxo-dodecanol 5,200 28 4.5 methacrylate-30 EO (15) A7 AA (10) b1-1 (70) Oxo-dodecanol 8,400 27.7 4.5 methacrylate-30 EO (20) A8 AA (10) b1-1 (89) Oxo-dodecanol 560 31.8 5.6 methacrylate-30 EO (1) A9 AA (10) b1-1 (80) n-Dodecanol 1,400 29.2 5.2 methacrylate-30 EO (10) A10 AA (10) b1-2 (80) n-Dodecanol 3,200 25.5 5.2 methacrylate-30 EO (10) A11 AA (10) b1-1 (80) n-Docosanol 7,200 25.3 5.5 methacrylate-25 EO (10) A12 AA (10) b1-1 (85) n-Dodecanol 1,000 29.0 4.6 methacrylate-23 EO (5)
B—Preparation and Characterization of Compositions According to the Invention and of Comparative Compositions

(68) Compositions for paper coating colours are prepared. The polymers according to the invention or polymers of the state of the art are employed in combination with the following products: pigment CaCO.sub.3: H60, H90 or H95 Hydrocarb Omya, pigment kaolin: Hydragloss 90 Kamin, binding agent: latex DL 1066 Trinseo, binding agent: starch Stabilys A30 Roquette, thickening agent: carboxymethylcellulose (CMC) Finnfix 10 CP Kelco, optical brightener: Blankophor PT Blankophor Gmbh, activating agent for optical brightness: polyvinyl alcohol (PV—OH) M 4-98 Chang Chung Petrochemical, commercial thickening copolymer based on acrylic polymer Rheocoat 35 Coatex, commercial thickening copolymer based on acrylic polymer Rheocoat 73 Coatex, commercial thickening copolymer based on acrylic polymer Rheocoat 93 Coatex, commercial thickening copolymer based on acrylic polymer Rheocarb 101 Coatex and commercial thickening formulation based on acrylic polymer Rheocarb 131 Coatex.

(69) The compositions are applied conventionally to paper as priming coat or as top coat. The application as top coat is carried out on precoated base paper of 78 g/m.sup.2 using a trailing-blade pilot coater from Dow and final calendering at 80° C., 40 bar and two passes per face.

(70) The solids content of the compositions prepared is measured using a heat chamber at 110° C. 1 g of product is placed in the heat chamber for 1 h. The difference in weight before and after drying makes it possible to determine the solids content.

(71) The pH is measured at 25° C. with a pH meter of WTW trade mark equipped with a conventional electrode coupled to a temperature probe.

(72) The Brookfield viscosity of the compositions prepared is measured at 10 rev/min and at 25° C. using an analogue viscometer. The spindle is chosen as a function of the viscosity of the composition under consideration in order to be within the optimum use range of the rheometer.

(73) The ACAV capillary viscosity at 10.sup.6 s.sup.−1 is measured using an ACAV A2 capillary viscometer from ACA.

(74) The water retention is determined using an AAGWR device from Gradek. It comprises a measurement chamber in which a test paper (Test Blotter Paper Gradek), covered with a perforated plastic fabric (Test Filter PCTE Gradek—2 μm), is positioned. 10 ml of paper coating colour are subsequently introduced into the chamber. The AAGWR device makes it possible to exert a pressure (1.5 bar) on the paper coating colour, resulting in all or part of the water and water-soluble substances present in the colour passing through the perforated plastic fabric and migrating into the test paper. A pressure of 1.5 bar is applied for 90 s. The difference between the weight of the test paper before the measurement (W0) and after the measurement (W1) gives the amount of water and of water-soluble substances present in the paper coating colour which have migrated into the test paper during the measurement. The relative value for increase in the water retention is equal to 1,250×(W1−W0)/W0.

(75) The weight of the coat is determined by subtracting the weight of a coated paper, obtained by cutting out a disc of coated paper of a hundredth of a square metre, from the weight of a disc of a hundredth of a square metre of virgin paper.

(76) The R457 whiteness with or without UV irradiation (R 457+UV and R 457−UV) and the opacity of the samples of coated paper are measured using an Elrepho 3,000 device from Datacolor.

(77) The W (CIE) whiteness is measured according to Standard ISO FDIS 11475. It is representative of the degree of optical brightness of the coated paper.

(78) The TAPPI 75° DIN whiteness is measured according to Standard TAPPI T480 OS-78 using a glossmeter from Lehmann Cotem.

Example B1: Compositions for Starch Free Priming Paper Coating Colours

(79) The different components are mixed according to the proportions (g) presented in Table 2.

(80) TABLE-US-00002 TABLE 2 Composition According to the Comparative invention B1 B2 B3 B4 B5 B6 B7 H60 100 100 100 100 100 100 100 DL 1066 9 9 9 9 9 9 9 Finnfix 10 0.63 Rheocoat 0.35 35 Rheocoat 0.18 93 Rheocarb 0.72 131 Polymer 1.21 A9 Polymer 1.1 A3

(81) The properties of the compositions are evaluated and the results are presented in Table 3.

(82) TABLE-US-00003 TABLE 3 Composition According to the Comparative invention B1 B2 B3 B4 B5 B6 B7 Solids content 71.3 71.6 71.6 71.6 71.5 70.8 71.4 pH 8.8 8.8 8.8 8.8 8.8 8.8 8.8 Brookfield viscosity 285 2,000 2,020 2,255 1,680 1,500 1,600 Capillary viscosity 70 79 138 104 119 72 76 Water retention 413 266 120 141 99 67 66

(83) Despite viscosities which would be acceptable for the deposition and the handling as paper coating colour, in particular for facilitating the surface application of the formulation on the paper, the composition B2 comprising a cellulose thickener (CMC, Finnfix 10) exhibits a water retention which is insufficient for such a use. The solids content of this composition would be unstable during the surface application.

(84) Unlike the compositions according to the invention B6 and B7, the comparative compositions B3, B4 and B5 do not make it possible to combine a low capillary viscosity and a reduced water retention value.

Example B2: Compositions for Paper Pre-Coating Colours with Starch

(85) The different components are mixed according to the proportions (g) presented in Table 4. Three repetitions were carried out.

(86) TABLE-US-00004 TABLE 4 Composition According to the Comparative invention B8 B9 B10 B11 B12 B13 B14 B15 H60 100 100 100 100 100 100 100 100 DL 1066 9 6 6 6 9 9 9 9 Stabilys 0 4 4 4 4 4 4 4 A30 Finnfix 10 0.26 Rheocoat 0.07 93 Rheocarb 0.2 131 Polymer 0.2 0.2 0.2 A9

(87) The properties of the compositions are evaluated and the results are presented in Table 5.

(88) TABLE-US-00005 TABLE 5 Composition Comparative According to the invention B8 B9 B10 B11 B12 B13 B14 B15 Solids content 71.6 71.6 70.6 71.5 71 71 71 71 pH 8.8 8.8 8.8 8.8 9 8.9 8.9 8.9 Brookfield viscosity 380 740 2,110 2,440 1,960 1,950 2,055 2,050 Capillary viscosity 76 123 118 153 142 124 111 118 Water retention 401 123 125 97 78 83 80 83

(89) In the presence of starch, unlike the compositions according to the invention B12 to B15, for the comparative compositions B9 to B11, the water retention is improved to the detriment of an increase in the capillary viscosity.

Example B3: Compositions for Starch Free Priming Paper Top-Coating Colours

(90) The different components are mixed according to the proportions (g) presented in Table 6.

(91) TABLE-US-00006 TABLE 6 Composition Comparative According to the invention B16 B17 B18 B19 Hydrocarb H95 100 100 100 100 DL 1066 9 9 9 9 M 4-98 0.5 0.5 0.5 0.5 Blankophor PT 1 1 1 1 Rheocoat 73 0.13 Polymer A9 0.34 Polymer A3 0.34

(92) The properties of the compositions are evaluated and the results are presented in Table 7.

(93) TABLE-US-00007 TABLE 7 Composition Comparative According to the invention B16 B17 B18 B19 Solids content 70.5 69 70.5 70.5 pH 8.8 8.6 8.7 8.6 Brookfield viscosity 460 1.050 740 710 Capillary viscosity 154 164 133 135 Water retention 192 134 108 110 Coat weight 13 15 13 13 R 457 + UV Whiteness 96.3 93.5 97.4 97.5 R 457 − UV Whiteness 85.5 84.2 85.6 85.7 W CIE Whiteness 118 110 122 122 Opacity 92 93 92 92 Gloss 76 74 75 75

(94) Again, despite viscosities which would be acceptable for the deposition and the handling as paper coating colour, in particular for facilitating the surface application of the formulation on the paper, the comparative compositions exhibit a water retention which is insufficient for such a use. The solids content of these compositions would be unstable during the surface application.

(95) Unlike the compositions according to the invention B18 and B19, the comparative compositions B16 and B17 do not make it possible to combine a low capillary viscosity and a reduced water retention value.

(96) In addition, the compositions according to the invention make it possible to retain or to improve the optical properties of the coated papers.

Example B4: Compositions for Paper Top-Coating Colours with Starch

(97) The different components are mixed according to the proportions (g) presented in Table 8.

(98) TABLE-US-00008 TABLE 8 Composition Comparative According to the invention B21 B22 B23 B24 B25 H95 Me 100 100 100 100 100 DL 1066 8 8 8 8 8 Stabilys A30 2 2 2 2 2 M 4-98 0.5 0.5 0.5 0.5 0.5 Blankophor PT 0.8 0.8 0.8 0.8 0.8 Rheocarb 101 0.5 Polymer A9 0.5 Polymer A12 0.5 Polymer A3 0.5

(99) The properties of the compositions are evaluated and the results are presented in Table 9.

(100) TABLE-US-00009 TABLE 9 Composition Comparative According to the invention B21 B22 B23 B24 B25 Solids content 70.2 70.1 70 70 70.2 pH 9 9 9 9 9 Brookfield viscosity 664 1.600 1.800 1.690 1.595 Capillary viscosity 152 165 147 123 104 Water retention 111 71 69 62 55 Coat weight 13 13 13 14 14 R 457 + UV Whiteness 98.4 98.9 99.2 99.4 99.5 R 457 − UV Whiteness 85.9 86 86.1 86.2 86.3 W CIE Whiteness 125 128 128 129 129 Gloss 73 72 70 70 72

(101) Again, the compositions according to the invention have a capillary viscosity and a water retention which render them usable as paper coating colours which are improved with respect to the comparative compositions.