NOVEL WATER-SOLUBLE POLYMER COMPLEXES IN THE FORM OF AN INVERSE EMULSION AND USES THEREOF

Abstract

The present invention relates to a polymer complex obtained by inverse emulsion polymerization of water-soluble monomers: in the presence of a cationic water-soluble host polymer comprising amine functions.

Claims

1. A polymer complex obtained by inverse emulsion polymerization of water-soluble monomers: in the presence of a cationic water-soluble host polymer comprising amine functions.

2. The polymer complex according to claim 1, wherein the host polymer is chosen from poly-(dimethylamine (co)epichlorohydrin) and poly(dimethylamine-co-epichlorohydrin-co-ethylenediamine).

3. The polymer complex according to claim 1, wherein the host polymer is poly(dimethylamine-co-epichlorohydrin-co-ethylenediamine).

4. The polymer complex according to claim 1, wherein the mass ratio between the water-soluble monomers and the host polymer is between 99/1 and 1/99.

5. The polymer complex according to claim 1, wherein the water-soluble monomers are chosen from the group consisting of: quaternary ammonium salts of dimethylaminoethyl acrylate (ADAME); quaternary ammonium salts of dimethylaminoethyl methacrylate (MADAME); dimethyldiallylammonium chloride (DADMAC); acrylamido propyltrimethyl ammonium chloride (APTAC); methacrylamido propyltrimethyl ammonium chloride (MAPTAC); acrylamide; N-isopropylacrylamide; N,N-dimethylacrylamide; N-vinylformamide; N-vinylpyrrolidone; acrylic acid; methacrylic acid; itaconic acid; crotonic acid; maleic acid; fumaric acid; 2-acrylamide 2-methylpropane sulfonic acid; vinylsulfonic acid; vinyl phosphoric acid; allylsulfonic acid; allylphosphonic acid; styrene sulfonic acid; water-soluble alkali metal, alkaline earth metal, or ammonium salts of these monomers.

6. A process for preparing the polymer complex according to claims 1, comprising the following steps: preparing an aqueous phase comprising at least one host polymer and water-soluble monomers; emulsifying said aqueous solution in an oil phase; and obtaining the polymer complex by polymerization of the water-soluble monomers.

7. The process according to claim 6, wherein the polymerization is carried out in the absence of a branching agent or crosslinking agent of polyfunctional ethylenic type.

8. A process for the manufacture of a sheet of paper, cardboard or the like, wherein, before forming said sheet, a polymer complex according to claim 1 is added to a suspension of fibers at one or more injection points.

9. The process according to claim 8, wherein the amount of polymer complex added is, by dry weight, between 3 g/ton of fibers and 10,000 g/ton of fibers.

10. A process for the manufacture of paper, cardboard or the like, comprising the following steps, on a paper machine: placine fibers in an aqueous suspension; adding the polymer complex according to claim 1; forming a sheet of paper, cardboard or the like on the wire surface of the paper machine; and drying the sheet.

11. The process for the manufacture of paper, cardboard or the like, according to claim 10, wherein the process comprises adding, before said forming the sheet of paper, at least one additive, different from the polymer complex, chosen from coagulants, retention agents, flocculants and starch.

12. The polymer complex according to claim 2, wherein the mass ratio between the water-soluble monomers and the host polymer is between 99/1 and 1/99.

13. The polymer complex according to claim 12. wherein the mass ratio between the water-soluble monomers and the host polymer is between 95/5 and 40/60.

14. The polymer complex according to claim 3, wherein the mass ratio between the water-soluble monomers and the host polymer is between 99/1 and 1/99.

15. The polymer complex according to claim 14, wherein the mass ratio between the water-soluble monomers and the host polymer is between 95/5 and 40/60.

16. The polymer complex according to claim 4, wherein the mass ratio between the water-soluble monomers and the host polymer is between 95/5 and 40/60.

17. The process according to claim 9, wherein the amount of polymer complex added is, by dry weight, between 10 g/ton of fibers and 7000 g/ton of fibers.

18. The process according to claim 9, wherein the amount of polymer complex added is, by dry weight, between 30 g/ton of fibers and 3000 g/ton of fibers.

19. The process according to claim 9, wherein fibers are cellulosic fibers.

20. The process according to claim 10, wherein fibers are cellulosic fibers.

Description

LIST OF FIGURES

[0053] FIG. 1 shows a graph of UL viscosity versus monomer/polyamine ratio.

[0054] FIG. 2 shows the percentage of improvement in thick stock dewatering and the turbidity measurement, compared to a reference test (blank).

[0055] FIG. 3 shows the percentage of improvement in vacuum dewatering in dilute stock and the turbidity measurement, compared to a reference test (blank).

[0056] FIG. 4 shows vacuum dewatering performance in dilute stock and turbidity measurement, compared to a reference test (blank).

[0057] FIG. 5 shows the dryness value before pressing, compared to a reference test (blank).

[0058] FIG. 6 shows the percentage of improvement in vacuum dewatering in dilute stock and the turbidity measurement, compared to a reference test (blank).

[0059] FIG. 7 shows vacuum dewatering performance in dilute stock and turbidity measurement, compared to a reference test (blank).

[0060] FIG. 8 shows the improvement (in percentage) of vacuum dewatering in dilute stock and the turbidity measurement, compared to a reference test (blank).

EXAMPLES OF EMBODIMENTS OF THE INVENTION

[0061] In the following examples: [0062] Polyamine H-1 is a structured poly-(dimethylamine/epichlorohydrin/ethylenediamine) with a Brookfield viscosity of 850 cps (Module LV2, 30 rpm.sup.−1, 23° C.) at 50% of active ingredient by weight in water. [0063] Polyamine H-2 is a linear poly-(dimethylamine/epichlorohydrin) with a Brookfield viscosity of 30 cps (Module LV1, 60 rpm.sup.−1, 23° C.) at 50% of active ingredient by weight in water. [0064] P-3: is a polymer in the form of an anionic inverse emulsion, linear poly-(acrylamide/acrylic acid), with a viscosity of UL=8.16 cps (Brookfield viscosity, Modulus UL, NaCl 1M, 60 rpm.sup.−1, 23° C.) at 29% of active ingredient by weight in water. [0065] P-4: is a polymer in cationic powder form, linear poly-(acrylamide/dimethylaminoethyl acrylate, MeCl), with a viscosity of UL=4.11 cps (Brookfield viscosity, Modulus UL, NaCl 1M, 60 rpm.sup.−1, 23° C.) at 92% of active ingredient by weight in water. [0066] Bentonite: Inorganic microparticle, marketed by Clariant under the name OPAZIL ABG.

Synthesis of a Polymer in Inverse Emulsion P1

[0067] The aqueous phase is prepared by adding 359.8 g of acrylamide (50% solution by weight in water), 262.6 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water) and 90.2 g of water. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS (mass in dry monomers) of potassium bromate and 800-1500 ppm/MS of sodium diethylenetriaminepentaacetate are added as initiators.

[0068] The organic phase is prepared by adding to a reactor 234.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of oil-in-water surfactant polymer (Rhodibloc RS).

[0069] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0070] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0071] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 4.21 cps is obtained for an active ingredient of 39% by weight.

Synthesis of the Polymer in Inverse Emulsion P2

[0072] The aqueous phase is prepared by adding 491.3 g of acrylamide (50% solution by weight in water), 92.9 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water) and 149.2 g of water. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0073] The organic phase is prepared by adding 213.2 g of Exxsol D100S oil, 26 g of sorbitan monooleate and 3.8 g of surfactant polymer (Rhodibloc RS) to a reactor.

[0074] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion. The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0075] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 4.26 cps is obtained for an active ingredient of 32% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-1)

[0076] The aqueous phase is prepared by adding 369.1 g of acrylamide (50% solution by weight in water), 256.8 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 2.2 g of water and 82.5 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0077] The organic phase is prepared by adding to a reactor 234.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS).

[0078] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0079] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0080] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.81 cps is obtained for an active ingredient of 43.1% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-2)

[0081] The aqueous phase is prepared by adding 290.6 g of acrylamide (50% solution by weight in water), 212.1 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 1 g of water and 213.4 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid.

[0082] Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0083] The organic phase is prepared by adding to a reactor 234.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS).

[0084] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0085] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55 ° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0086] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.71 cps is obtained for an active ingredient of 42.1% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-3)

[0087] The aqueous phase is prepared by adding 287.8 g of acrylamide (50% solution by weight in water), 210.1 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 0.7 g of water and 237.5 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0088] The organic phase is prepared by adding to a reactor 214.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS).

[0089] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0090] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55 ° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0091] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.46 cps is obtained for an active ingredient of 43.1% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-4)

[0092] The aqueous phase is prepared by adding 250.9 g of acrylamide (50% solution by weight in water), 183.1 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 0.9 g of water and 280.1 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0093] The organic phase is prepared by adding to a reactor 234.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS). The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0094] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0095] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.01 cps is obtained for an active ingredient of 41.2% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-5)

[0096] The aqueous phase is prepared by adding 184.5 g of acrylamide (50% solution by weight in water), 134.7 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 0.5 g of water and 396 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0097] The organic phase is prepared by adding to a reactor 234.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS).

[0098] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0099] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0100] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 2.51 cps is obtained for an active ingredient of 39.8% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-6)

[0101] The aqueous phase is prepared by adding 439.1 g of acrylamide (50% solution by weight in water), 83.1 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 0.2 g of water and 214 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid.

[0102] Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0103] The organic phase is prepared by adding 213.2 g of Exxsol D100S oil, 26 g of sorbitan monooleate and 3.8 g of surfactant polymer (Rhodibloc RS) to a reactor.

[0104] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0105] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0106] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.61 cps is obtained for an active ingredient of 39.3% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-7)

[0107] The aqueous phase is prepared by adding 287.8 g of acrylamide 50% by weight in water, 210.1 g of dimethylaminoethyl acrylate, MeCl 80% by weight in water, 0.7 g of water and 237.5 g of polyamine H-2. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0108] The organic phase is prepared by adding to a reactor 214.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS).

[0109] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0110] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. Polymerization is initiated by adding sodium bisulphite using a syringe pump. The temperature is raised to then maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0111] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.31 cps is obtained for an active ingredient of 43.1% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-8)

[0112] The aqueous phase is prepared by adding 537.3 g of acrylamide 50% by weight in water, 101.7 g of dimethylaminoethyl acrylate, MeCl 80% by weight in water, 0.7 g of water and 73 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0113] The organic phase is prepared by adding 210.3 g of Exxsol D100S oil, 25.9 g of sorbitan monooleate and 3.7 g of surfactant polymer (Rhodibloc RS) to a reactor.

[0114] The aqueous phase is then transferred to the organic phase and then emulsified, for example with Ultra-Turax, at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0115] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. Polymerization is initiated by adding sodium bisulphite using a syringe pump. The temperature is raised to then maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0116] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 4.01 cps is obtained for an active ingredient of 38.6% by weight.

Synthesis of a Complex in Inverse Emulsion According to the Invention (I-9)

[0117] The aqueous phase is prepared by adding 280.5 g of acrylamide (50% solution by weight in water), 204.7 g of dimethylaminoethyl acrylate, MeCl (80% solution by weight in water), 0.7 g of water and 227.5 g of polyamine H-1. The pH of the solution is adjusted between 4 and 5 with adipic acid. 2-25 ppm/MS of sodium hypophosphite is added as a limiting agent as well as 2-25 ppm/MS of methylene bis acrylamide as a cross-linking agent. Subsequently, 100-250 ppm/MS potassium bromate and 800-1500 ppm/MS sodium diethylenetriaminepentaacetate are added as initiators.

[0118] The organic phase is prepared by adding to a reactor 211.2 g of Exxsol D100S oil, 4.7 g of sorbitan monooleate, 8.2 g of sorbitan monooleate 3 EO (oxyethylene group), 11.1 g of sorbitan monooleate 5 EO (oxyethylene group) and 4.8 g of surfactant polymer (Rhodibloc RS).

[0119] The aqueous phase is then transferred to the organic phase and then emulsified with Ultra-Turax at 8000 rpm for 1 minute in order to obtain a uniform inverse emulsion.

[0120] The inverse emulsion is deoxygenated with a nitrogen sparge for 30 min. The polymerization is initiated by adding sodium bisulphite and the temperature is maintained at 55° C. for approximately 1.5 hours. The reaction medium is finally treated with an excess of sodium bisulphite to reduce the free monomers.

[0121] Once the inverse emulsion is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C. ). A UL viscosity of 2.31 cps is obtained for an active ingredient of 41.8%.

[0122] Concerning the stability of the inverse emulsions according to the invention (I-1 to I-9), we do not observe any phase-shift after several weeks of storage at room temperature.

Synthesis of a Mixture of Polymers in Inverse Emulsion (M-1)

[0123] In a 1L beaker, 767.8 g of the P2 emulsion are weighed and stirred using a half-moon type stirring blade. 205.2 g of polyamine H-1 are added slowly, then the mixture is left stirring for 10 min. to ensure its homogeneity. The mixture has an active ingredient of 35.8% by weight. A phase-shift of the mixture is observed after one week of storage at ambient temperature.

Synthesis of a Mixture of Polymers in Inverse Emulsion (M-2)

[0124] In a 1L beaker, 571.8 g of emulsion P1 are weighed and stirred using a half-moon type stirring blade. 300 g of polyamine H-1 are added slowly, then the mixture is left stirring for 10 min. to ensure its homogeneity. The mixture has an active ingredient of 38.2% by weight. A phase-shift of the mixture is observed after one week of storage at ambient temperature.

Synthesis of a Mixture of Polymers in Inverse Emulsion (M-3)

[0125] In a 1 L beaker, 759.9 g of the P2 emulsion are weighed and stirred using a half-moon type stirring blade. 54 g of polyamine H-1 are added slowly then the mixture is left stirring for 10 min. to ensure its homogeneity. The mixture has an active ingredient of 33.2% by weight. A phase-shift of the mixture is observed after one week of storage at room temperature.

Synthesis of a Polymer in Powder Form (C-1)

[0126] In a polymerization reactor, 748.7 g of 50% acrylamide, 126.2 g of dimethylaminoethyl acrylate, 80% MeCl, 431.5 g of water and 95 g of polyamine H-1 are charged. The pH of the solution is adjusted between 3 and 4 with adipic acid. The solution is cooled to a temperature between 0 and 2° C., then deoxygenated with nitrogen sparge for 15 min. Subsequently, 1-15 ppm/MS of sodium persulfate and 1-15 ppm/MS of Mohr's salt are added as initiators.

[0127] The reaction temperature increases from 0 to 90° C. and the polymer is obtained in the form of a gel. This gel is cut, chopped, dried for 45 min. at a temperature of 75° C., ground and finally sieved. A polymer is thus obtained in powder form with a particle size less than or equal to 1 mm. Once the polymer in powder form is completed, the Brookfield viscosity is measured (UL module, 1M NaCl 60 rpm.sup.−1, 23° C.). A UL viscosity of 3.76 cps is obtained for an active ingredient of 92.8% by weight in water.

TABLE-US-00001 TABLE 1 summary of examples and counter-examples (PA = polyamine, MA % = percentage of active ingredient by weight) Cationic Monomers/ monomer PA polyamine UL Name Form (% mol) type % by weight MA % (cps) P-1 Emulsion 30 NA 100/0  39 4.21 P-2 Emulsion 10 NA 100/0  32 4.26 H-l Liquid NA H-l  0/100 50 NA H-2 Liquid NA H-2  0/100 50 NA I-1 Emulsion 30 H-1 90/10 43 3.81 I-2 Emulsion 30 H-1 75/25 42 3.71 I-3 Emulsion 30 H-1 70/30 43 3.46 I-4 Emulsion 30 H-1 66/34 41 3.01 I-5 Emulsion 30 H-1 50/50 40 2.51 I-6 Emulsion 10 H-1 70/30 39 3.61 I-7 Emulsion 30 H-2 70/30 43 3.31 I-8 Emulsion 10 H-1 90/10 39 4.01 I-9 Emulsion 30 H-1 70/30 42 2.31 M-1 Mixed 10 H-1 70/30 36 4.26 M-2 Mixed 30 H-1 70/30 38 4.21 M-3 Mixed 10 H-1 90/10 33 4.26 C-1 Powder 10 H-1 90/10 93 3.76 P-3 Emulsions 30* NA 100/0  29 8.16 P-4 Powder 10 NA 100/0  92 4.11 *molar percentage of anionic monomer

TABLE-US-00002 TABLE 2 Summary of sequences for evaluations of polymer combinations Test Sequences No. 5 seconds 10 seconds 20 seconds  1 Blank  2 P-4  3 P-2 P-4  4 I-6 P-4  5 P-1 P-4  6 I-3 P-4  7 P-4 Bentonite  8 P-1 P-4 Bentonite  9 I-3 P-4 Bentonite 10 P-4 Bentonite P-3 11 P-1 P-4 Bentonite P-3 12 I-3 P-4 Bentonite P-3 13 P-4 P-3 14 P-1 P-4 P-3 15 I-3 P-4 P-3

[0128] The tests in Table 2 are analyzed by group: [2-4], [5-6], [7-8-9], [10-11-12], and [13-14-15].

Evaluation Test Procedures

Recycled Fiber Stock

[0129] The wet stock is obtained by disintegration of dry stock in order to obtain a final aqueous concentration of 4% by weight in water to produce the thick stock, which is diluted in water at 1% by weight to obtain the dilute stock. It is a pH-neutral stock made from 100% recycled cardboard fibers.

UL Viscosity Measurement

[0130] 500 mg of polymer (derived from the polymerization of the monomers, according to the invention or not) are added to 490 ml of deionized water. After complete dissolution, 29.25 grams of NaCl are added.

[0131] The viscosity is measured using a digital Brookfield DVII+ viscometer at a rotational speed of 60 rpm at 25° C. (UL module).

Evaluation of the Dewatering Performance (DDA)

[0132] The DDA (Dynamic Drainage Analyzer) is used to automatically determine the time (in seconds) required to drain a fibrous suspension under vacuum. The polymers are added to the wet stock (0.6 liter of stock at 1.0% by weight) in the DDA cylinder under stirring at 1000 rpm: [0133] According to the following sequence for the evaluation of a single polymer:

[0134] T=0 sec: stirring the stock

[0135] T=10 sec: adding the cationic dewatering agent (350 g/t)

[0136] T=30 sec: stirring stopped and dewatering under vacuum at 200 mBar for 60 sec [0137] According to the following sequence for the evaluation of a combination of polymers:

[0138] T=0 sec: stirring the dough

[0139] T=5 sec: adding the cationic dewatering agent (350 g/t)

[0140] T=10 sec: adding the cationic polymer (250 g/t)

[0141] T=20 sec: adding the anionic polymer (150 g/t) and/or the bentonite (1.5 kg/t)

[0142] T=30 sec: stirring stopped and dewatering under vacuum at 200 mBar for 60 sec

[0143] The dosages are expressed in grams of active ingredient/ton of fibers (dry weight in fibers, advantageously cellulosic).

[0144] The pressure under the wire surface is recorded as a function of time. When all the water is evacuated from the fibrous pad, the air passes through it, causing a break in the slope to appear on the curve, representing the pressure under the wire surface as a function of time. The time, expressed in seconds, recorded at this break in slope, corresponds to the dewatering time. The shorter the time, the better the vacuum dewatering.

[0145] In addition, the turbidity of the white water resulting from the DDA measurement is measured. The lower the turbidity value, the greater the retention of solid particles in the fibrous pad.

Dryness

[0146] The DDA test allows free water to be drained from the fibrous suspension under vacuum. The purpose of the dryness test is to measure the amount of water bound in the fibrous pad. To that end, the cake of fibrous pad obtained from the DDA test is recovered and its mass is measured before and after drying in an oven at 105° C. for 2 hours. The ratio of the two masses gives the dryness. The higher this value, the more the dewatering polymer removes bound water.

Evaluation of the Dewatering Performance in Thick Stock

[0147] In a beaker, 500 ml of thick stock at 4% in water is treated, subjected to a low shear rate (stirring speed of 300 rpm). The polymer is added to this fibrous suspension with a contact time T=1 min.

[0148] This treated stock is transferred to the Canadian Standard Freeness Tester.

[0149] The volume of water released over time is recorded. The more water released, the better the dewatering of the thick stock.

Turbidity

[0150] Turbidity refers to the content of suspended matter that clouds the fluid. It is measured using a HANNA spectrophotometer, which measures the decrease in the intensity of the light ray at a 90° angle and at an 860 nm wavelength, expressed in NTU.

[0151] FIG. 1 demonstrates that, all things being otherwise equal, the UL viscosity drops when the monomer/polyamine ratio drops. This leads to the conclusion that the polyamine acts as a transfer agent to the polymer.

[0152] FIGS. 2 and 3 demonstrate that, whatever the products of the invention (I-1 to I-5) with respect to the polymer alone (P-1) and with respect to the polyamine alone (H-1), there is a synergistic effect between the improvement in thick stock dewatering, vacuum dewatering of dilute stock (DDA) as well as turbidity. In this case, the monomer/polyamine mass ratio of 70/30 (I-3) makes it possible to obtain the most favorable combination of gain in thick stock dewatering/vacuum dewatering of the dilute stock (DDA)/turbidity.

[0153] FIGS. 4 and 5 demonstrate that the products of the invention (I-3 and I-6) are much more efficient in vacuum dewatering of the dilute stock, in turbidity, as well as in dryness before press compared to the corresponding mixtures (M-1 and M-2) and to the products alone (H-1, P-1 and P-2).

[0154] FIG. 6 demonstrates that, whatever the products of the invention (I-3 and I-7) compared to the products alone (P-1, H-1, H-2), there is a synergistic effect between the improvement in vacuum dewatering of the dilute stock (DDA) as well as turbidity. In this specific case, it should be noted that the structure of the polyamine has a positive impact on the application performance compared to a linear polyamine.

[0155] FIG. 7 demonstrates that polymerization in the form of an inverse emulsion (I-8) remains much more efficient compared to the corresponding powder form (C-1) and mixture (M-3). In addition, polymerization in inverse emulsion form, with a polyamine, makes it possible to solve the stability problem of the simple mixture.

[0156] According to FIG. 8, in tests 2 to 15, the products of the invention I-3 and I-6, tested in comparison and respectively with the products P-1 and P-2 (Table 2; Test 4 vs 2 and 3, Test 6 vs 2 and 5, Test 9 vs 7 and 8, Test 12 vs 10 and 11, and Test 15 vs 13 and 14), in combination with a retention system (single or multi-component), provide better performance in terms of improved dilute stock vacuum dewatering (DDA) as well as reduced turbidity.