FINELY DIVIDED, STARCH-CONTAINING POLYMER DISPERSIONS, PROCESSES FOR THEIR PREPARATION AND USE AS SIZES IN PAPERMAKING

Abstract

The invention relates to a finely divided, starch-containing aqueous polymer dispersion which is obtainable by free radical emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one redox initiator and starch, wherein the ethylenically unsaturated monomers comprise (a) from 30 to 65% by weight of acrylonitrile and/or methacrylonitrile, (b) from 35 to 60% by weight of at least one C.sub.1-C.sub.12-alkyl acrylate and/or at least one C.sub.1-C.sub.12-alkyl methacrylate, (c) from 0 to 35% by weight of at least one other ethylenically unsaturated copolymerisable monomer, in which the sum of (a), (b) and (c) totals 100%, and in which the aqueous polymer dispersion comprises, (d) from 10 to 55% by weight of an ionic tapioca starch, in which the weight of (d) is based on the total solids of components (a), (b), (c) and (d) of the aqueous polymer dispersion. The invention also relates to a process for the manufacture of the finely divided, starch containing aqueous polymer dispersions and also to the use of said finely divided starch containing aqueous polymer dispersions as a size for paper, board and cardboard.

Claims

1: A finely divided, starch-containing aqueous polymer dispersion which is obtained by free radical emulsion polymerization of ethylenically unsaturated monomers in the presence of at least one redox initiator and starch, wherein the ethylenically unsaturated monomers comprise: (a) from 30 to 65% by weight of acrylonitrile and/or methacrylonitrile, (b) from 35 to 60% by weight of at least one C.sub.1-C.sub.12-alkyl acrylate and/or at least one C.sub.1-C.sub.12-alkyl methacrylate, (c) from 0 to 35% by weight of at least one other ethylenically unsaturated copolymerisable monomer, wherein the sum of (a), (b) and (c) totals 100%, and wherein the aqueous polymer dispersion comprises: (d) from 10 to 55% by weight of an ionic tapioca starch, wherein the weight of (d) is based on the total solids of components (a), (b), (c) and (d) of the aqueous polymer dispersion.

2: The finely divided, starch containing aqueous polymer dispersion according to claim 1, wherein the ionic tapioca starch is a degraded starch with a molar mass Mw of from 1,000 to 65,000 g/mol.

3: The finely divided, starch containing aqueous polymer dispersion according to claim 1, wherein the ionic tapioca starch is anionic or cationic.

4: The finely divided, starch containing aqueous polymer dispersion according to claim 1, wherein the free radical emulsion polymerization is carried out in the presence of at least 0.01% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

5: The finely divided, starch-containing aqueous polymer dispersion according to claim 1, wherein the ethylenically unsaturated monomers comprise: (a) from 40 to 60% by weight of acrylonitrile and/or methacrylonitrile, (b) from 40 to 60% by weight of at least one C.sub.1-C.sub.12-alkyl acrylate and/or at least one C.sub.1-C.sub.12-alkyl methacrylate, (c) from 0 to 20% by weight of at least one other ethylenically unsaturated copolymerisable monomer, wherein the sum of (a), (b) and (c) totals 100%, and wherein the aqueous polymer dispersion comprises: (d) from 10 to 55% by weight of an anionic or cationic degraded tapioca starch with a molar mass Mw of from 1,000 to 65,000 g/mol, in which the weight of (d) is based on the total solids of components (a), (b), (c) and (d) of the aqueous polymer dispersion, and the free radical emulsion polymerization is carried out in the presence of at least 0.01% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

6: The finely divided, starch-containing aqueous polymer dispersion according to claim 3, wherein the ethylenically unsaturated monomers comprise: (a) from 40 to 60% by weight of acrylonitrile and/or methacrylonitrile, (b) from 40 to 60% by weight of at least two of C.sub.1-C.sub.12-alkyl acrylate and/or C.sub.1-C.sub.12-alkyl methacrylate, (c) from 0 to 20% by weight of at least one other ethylenically unsaturated copolymerisable monomer, wherein the sum of (a), (b) and (c) totals 100%, and wherein the aqueous polymer dispersion comprises: (d) from 10 to 55% by weight of an anionic or cationic degraded tapioca starch with a molar mass Mw of from 1,000 to 65,000 g/mol, in which the weight of (d) is based on the total solids of components (a), (b), (c) and (d) of the aqueous polymer dispersion, and the free radical emulsion polymerization is carried out in the presence of at least 0.01% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

7: The finely divided, starch-containing aqueous polymer dispersion according to claim 1, wherein the ethylenically unsaturated monomers comprise: (a) from 40 to 60% by weight of acrylonitrile and/or methacrylonitrile, (b) from 40 to 60% by weight of at least two of C.sub.1-C.sub.12-alkyl acrylate and/or C.sub.1-C.sub.12-alkyl methacrylate comprising (b1) at least one C.sub.1-C.sub.4-alkyl acrylate and/or at least one C.sub.1-C.sub.4-alkyl methacrylate, and (b2) at least one C.sub.5-C.sub.12-alkyl acrylate and/or at least one C.sub.5-C.sub.12-alkyl methacrylate, (c) from 0 to 20% by weight of at least one other ethylenically unsaturated copolymerisable monomer, wherein the sum of (a), (b) and (c) totals 100%, and wherein the aqueous polymer dispersion comprises, (d) from 10 to 55% by weight of an anionic or cationic degraded tapioca starch with a molar mass Mw of from 1,000 to 65,000 g/mol, in which the weight of (d) is based on the total solids of components (a), (b), (c) and (d) of the aqueous polymer dispersion, and the free radical emulsion polymerization is carried out in the presence of at least 0.01% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

8: The finely divided, starch-containing aqueous polymer dispersion according to claim 7, wherein component (b1) is at least one member selected from the group consisting of n-butyl acrylate and tertiary butyl acrylate and component (b2) is 2-ethylhexyl acrylate.

9: The finely divided, starch containing aqueous polymer dispersion according to claim 7, wherein the ratio of component (b1) to component (b2) is 10:1 to 1:1.

10: The finely divided, starch-containing aqueous polymer dispersion according to claim 1, wherein the ethylenically unsaturated monomers comprise: (a) from 40 to 60% by weight of acrylonitrile and/or methacrylonitrile, (b) from 40 to 60% by weight of at least two of C.sub.1-C.sub.4-alkyl acrylate and/or C.sub.1-C.sub.4-alkyl methacrylate, (c) from 0 to 20% by weight of at least one other ethylenically unsaturated copolymerisable monomer, wherein the sum of (a), (b) and (c) totals 100%, and wherein the aqueous polymer dispersion comprises: (d) from 10 to 55% by weight of an anionic or cationic degraded tapioca starch with a molar mass Mw of from 1,000 to 65,000 g/mol, in which the weight of (d) is based on the total solids of components (a), (b), (c) and (d) of the aqueous polymer dispersion, and the free radical emulsion polymerization is carried out in the presence of at least 0.01% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

11: The finely divided, starch-containing aqueous polymer dispersion according to claim 10, wherein component (b) is a mixture that comprises at least one of n-butyl acrylate and tertiary butyl acrylate.

12: The finely divided, starch-containing aqueous polymer dispersion according to claim 1, wherein the free radical emulsion polymerization is carried out in the presence of at least 0.01% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one monocyclic monoterpene chain transfer agent.

13: The finely divided, starch-containing aqueous polymer dispersion according to claim 12, wherein the monocyclic monoterpene is terpinolene.

14: The finely divided, starch-containing aqueous polymer dispersion according to claim 1, wherein the free radical emulsion polymerization is carried out in the presence of 0.01 to 10% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

15: The finely divided, starch-containing aqueous polymer dispersion according to claim 1, wherein the free radical emulsion polymerization is carried out in the present of 0.01 to 5% by weight, based on the weight of the ethylenically unsaturated monomers, of at least one terpene containing chain transfer agent.

16: A process for the preparation of a finely divided, starch-containing aqueous polymer dispersion according to claim 1, the process comprising: polymerizing, by free radical emulsion polymerization, the ethylenically unsaturated monomers in the presence of the at least one redox initiator and the starch.

17. (canceled)

18: A process of sizing paper, board, or cardboard, the method comprising, applying at least one finely divided, starch-containing aqueous polymer dispersion according to claim 1 to paper, board, or cardboard.

Description

EXAMPLE 1

[0086] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 98.56 gr of cationic tapioca starch, Ehcat 69 from EMS (DS=0.060-0.070) was dispersed in 438 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 0.38 gr of 25% concentration by weight aqueous calcium acetate solution and 2.2 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45-50 min of stirring. At a temperature of 85 C., 8.59 gr of -amylase (Termamyl 120L) was charged into the vessel and mixed for 30 min. The enzymatic starch degradation was stopped by adding 8.6 gr of glacial acetic acid solution. After the addition of 1.95 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 5.6 gr of an 18% strength by weight aqueous hydrogen peroxide solution the reaction was allowed to run with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feed of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 43.8 gr of demineralised water, 0.4 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 100 gr of Acrylonitrile, 80 gr of n-Butyl acrylate, 20 gr of 2-Ethyl hexyl acrylate and 0.79 gr terpinolene which were added at constant rate for 165 mins. Simultaneously the initiator feed 49.68 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it is cooled down to 60 C. After 5.03 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then mixed for 15 min, followed by adding 5.1 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited)(10%) for 60 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. Then 2.58 gr Acticid MBS, (a biocide available from Thor Specialty Chemical Company) and 1.23 gr defoamer (Afranil T from BASF) were added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 96.1% and a particle size of 91.2 nm.

EXAMPLE 2

[0087] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 138 gr of anionic oxidized tapioca starch (Ehstable 15 from EMS) was dispersed in 715 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 1.73 gr of 25% concentration by weight aqueous calcium acetate solution were added and the mixture was heated to 85 C. in the course of 45 min of stirring. At 85 C., 7.3 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) was added and then mixed for 20 min. Afterwards, the enzymatic starch degradation was stopped by adding 13.19 gr of glacial acetic acid solution. After the addition of 2.62 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 4.52 gr of an 18% strength by weight aqueous hydrogen peroxide solution the reaction was allowed to run with stirring for 15 min. The reaction temperature is further maintained at 85 C. Afterwards, the feeding of monomer and initiator into the vessel was started simultaneously. The monomer emulsion mixture consisted of 68 gr of demineralised water, 0.53 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 152.3 gr of acrylonitrile, 121.8 gr of n-Butyl acrylate, 30.45 gr of 2-ethyl hexyl acrylate and 1.19 gr terpinolene which were added at constant rate for 165 mins. Simultaneously the initiator feed 58.57 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it was cooled down to 60 C. After 8.68 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minutes and then mixed for 15 min, followed by adding 15.53 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. 1.55 gr Trilon B (Chelating agent, from BASF) was added and then the pH was adjusted to 4.5-5.5 using 25% strength Sodium Hydroxide. Afterwards, 2.58 gr biocide (Acticid MBS, Thor Specialty Chemical Company) and 0.12 gr defoamer (Afranil T from BASF) were added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 95.7% and a particle size of 101 nm.

EXAMPLE 3

[0088] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 141.4 gr of anionic oxidized tapioca starch (Ehstable 15 from EMS) was dispersed in 715 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 1.73 gr of 25% concentration by weight aqueous calcium acetate solution were added and the mixture was heated to 85 C. in the course of 45 min of stirring. At 85 C., 8.22 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) was added and then mixed for 20 min. Afterwards, the enzymatic starch degradation was stopped by adding 13.19 gr of glacial acetic acid solution. After the addition of 2.62 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 4.52 gr of an 18% strength by weight aqueous hydrogen peroxide solution was allowed to run with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 68 gr of demineralised water, 0.53 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 152.3 gr of acrylonitrile, 121.8 gr of n-Butyl acrylate, 30.45 gr of 2-ethyl hexyl acrylate which were added at constant rate for 165 mins. Simultaneously the initiator feed 58.57 gr of 18% strength by weight aqueous hydrogen peroxide solution was added over 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it was cooled down to 60 C. After 8.68 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then the reaction mixture was mixed for 15 min, followed by adding 15.53 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. Add 1.55 gr Trilon B (Chelating agent, from BASF) and then adjust the pH: 4.5-5.5 using 25% strength Sodium Hydroxide. Afterwards, 2.58 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 0.12 gr defoamer (Afranil T from BASF) were added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 95.1% and a particle size of 112 nm.

Comparative Example 1: (US Patent 2012/0180970)

[0089] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 87.32 gr of anionic oxidized tapioca starch (Ehstable 15 from EMS) was dispersed in 872 gr of demineralised water under nitrogen atmosphere and with stirring. Then the mixture was heated to 80 C. in the course of 45 min of stirring. At 80 C, 5.58 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) was added and then mixed for 20 min. Afterwards, the enzymatic starch degradation was stopped by adding 0.472 gr of glacial acetic acid solution (60%). Afterwards 3.63 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O) was added. The reaction temperature was further increased to 85 C. At 85 C., the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 128 gr of demineralised water, 0.64 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 117 gr of styrene, 58.25 gr of n-Butyl acrylate, 1.90 acrylic acid and 0.77 gr terpinolene (95%) which were added at constant rate for 120 mins. Simultaneously the initiator feed 43.138 gr of 10% strength by weight aqueous hydrogen peroxide solution was added over 150 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it was cooled down to 60 C. After 2.54 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then mixed for 15 min. Thereafter the reaction mixture was cooled down to room temperature. 2.42 gr formalin was added followed by the addition of 1.3 gr biocide (Acticid MBS from Thor Specialty Chemical Company) After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 95.8% and a particle size of 89 nm.

Comparative Example 2: European Patent (EP) 0276 770 B2

[0090] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 141.11 gr of anionic oxidized Potato starch (Amylex 15 from Sud Chemie) was dispersed in 715 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 1.73 gr of 25% concentration by weight aqueous calcium acetate solution were added and the mixture was heated to 85 C. in the course of 45 min of stirring. At 85 C., 7.3 gr of 1% aqueous solution of commercially--amylase (Termamyl 120L from Novo Nordisk) was added and then mixed for 20 min. Afterwards, the enzymatic starch degradation was stopped by adding 13.19 gr of glacial acetic acid solution. After the addition of 2.62 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 4.52 gr of an 18% strength by weight aqueous hydrogen peroxide solution the reaction was allowed to run with stirring for 15 min. The reaction temperature is further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 68 gr of demineralised water, 0.53 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 167.48 gr of acrylonitrile, 137.03 gr of n-Butyl acrylate were added at constant rate for 165 mins. Simultaneously the initiator feed 48.57 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it was cooled down to 60 C. After 8.68 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then mixed for 15 min, followed by adding 15.53 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. 1.55 gr Trilon B was added and then the pH was adjusted to 4.5-5.5 using 25% strength Sodium Hydroxide. Afterwards, 2.58 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 0.12 gr defoamer (Afranil T from BASF) were added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 93.8% and a particle size of 115 nm.

Comparative Example 3 (US Patent 2012/0180970)

[0091] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 89.82 gr of anionic oxidized Potato starch (Amylex 15 from Sud Chemie) was dispersed in 893 gr of demineralised water under nitrogen atmosphere and with stirring. Then the mixture was heated to 80 C. in the course of 45 min of stirring. At 80 C., 5.63 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) was added and then mixed for 20 min. Afterwards, the enzymatic starch degradation was stopped by adding 0.872 gr of glacial acetic acid solution (60%). 3.65 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O) was then added. The reaction temperature was further increased to 85 C. At 85 C., the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 128 gr of demineralised water, 0.65 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 117 gr of styrene, 58.25 gr of n-Butyl acrylate, 1.90 acrylic acid and 0.78 gr terpinolene (95%) were added at constant rate for 120 mins. Simultaneously the initiator feed 43.39 gr of 10% strength by weight aqueous hydrogen peroxide solution was added over 150 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it was cooled down to 60 C. After 2.84 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minutes and then the reaction mixture was mixed for 15 min. Thereafter the reaction mixture was cooled down to room temperature. 2.39 gr formalin and then 1.3 gr biocide (Acticid MBS from Thor Specialty Chemical Company) were added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 96.3% and a particle size of 86 nm.

[0092] The application test work was carried out on liner paper by passing the liner paper through the size press containing the respective compositions of the examples as sizing solutions. The respective sizing solution was used to wet size the liner paper and was then dried using the drying calendar at a temperature of 120 C. Afterwards, the size of paper was put in a conditioning humidity room for at least eight hours before making the Cobb 60 measurement. The results are presented in Tables 1 and 2.

TABLE-US-00001 TABLE 1 Application Test on Liner Paper (Based weight (BW): 150 gsm) Blank Ex1 Ex2 Ex 3 Comp1 Comp2 Comp3 Concentration 6 6 6 6 6 6 6 of Oxidised Tapioca Starch (%) PSA Dosage 0 1.5 2.0 1.5 2.0 1.5 2.0 1.5 2.0 1.5 2.0 1.5 2.0 (g/l) Cobb60 131 70 36 77 40 89 51 108 103 96 81 113 106 (g/m2)

TABLE-US-00002 TABLE 2 Application Test on Liner Paper (Bw: 150 gsm) Blank Ex1 Ex2 Ex 3 Comp1 Comp2 Comp3 Concentration 6 6 6 6 6 6 6 of OxidiSed Tapioca Starch (%) Alun (g/l) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 PSA Dosage 0 1.5 2.0 1.5 2.0 1.5 2.0 1.5 2.0 1.5 2.0 1.5 2.0 (g/l) Cobb60 130 35 25 40 24 52 36 80 53 63 39 95 73 (g/m2)

[0093] For determining the degree of sizing of the surface-sized papers, the Cobb.sub.60 value according to DIN EN 20 535 was determined. The water absorbing of the paper sheet in g/m.sup.2 after contact with water and a contact time of 60 s is defined as the Cobb.sub.60 value. The lower the Cobb.sub.60 value, the better is the sizing effect of the dispersion used.

EXAMPLE 4

[0094] In a polymerization vessel which equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 98.56 gr of cationic tapioca starch, Ehcat 69 (DS=0.060-0.070) (available from EMS) were dispersed in 438 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 0.38 gr of 25% concentration by weight aqueous calcium acetate solution and 2.2 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45-50 min of stirring. At a temperature of 85 C., 8.59 gr of -amylase (Termamyl 120L) was charged into the vessel and mixed for 30 min. The enzymatic starch degradation was stopped by adding 8.6 gr of glacial acetic acid solution. After the addition of 1.95 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 5.6 gr of an 18% strength by weight aqueous hydrogen peroxide solution was added with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 43.8 gr of demineralised water, 0.4 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 100 gr of Acrylonitrile, 80 gr of n-Butyl acrylate, 20 gr of 2-Ethyl hexyl acrylate and 0.79 gr terpinolene was added at constant rate for 165 mins. Simultaneously the initiator feed 49.68 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it is cooled down to 60 C. After 5.03 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then mixed for 15 min, followed by adding 5.1 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixed for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. Then add 2.58 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 1.23 gr defoamer (Afranil T available from BASF). After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 96.1% and a particle size of 91.2 nm.

EXAMPLE 5

[0095] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 98.56 gr of cationic tapioca starch, Ehcat 69 (DS=0.060-0.071) (from EMS) was dispersed in 438 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 0.38 gr of 25% concentration by weight aqueous calcium acetate solution and 2.2 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45-50 min of stirring. At a temperature of 85 C., 8.59 gr of -amylase (Termamyl 120L) was charged into the vessel and mixed for 30 min. The enzymatic starch degradation was stopped by adding 8.6 gr of glacial acetic acid solution. After the addition of 1.95 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 5.6 gr of an 18% strength by weight aqueous hydrogen peroxide solution was added with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feed of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 43.8 gr of demineralised water, 0.4 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 100 gr of Acrylonitrile, 80 gr of n-Butyl acrylate, 20 gr of 2-Ethyl hexyl acrylate and 1.60 gr terpinolene was added at constant rate for 165 mins. Simultaneously the initiator feed 49.68 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it is cooled down to 60 C. After 5.03 gr TBHP (tertiary butyl hydro peroxide) (10%) were added for 30 minutes and then mixed for 15 min, followed by adding 5.1 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixed for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. 2.58 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 1.23 gr defoamer (Afranil T available from BASF) were then added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 96.6% and a particle size of 87.1 nm

EXAMPLE 6

[0096] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 98.56 gr of cationic tapioca starch, Ehcat 69 (DS=0.060-0.070) was dispersed in 438 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 0.38 gr of 25% concentration by weight aqueous calcium acetate solution and 2.2 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45-50 min of stirring. At a temperature of 85 C., 8.59 gr of -amylase (Termamyl 120L) was charged into the vessel and mixed for 30 min. The enzymatic starch degradation was stopped by adding 8.6 gr of glacial acetic acid solution. After the addition of 1.95 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 5.6 gr of an 18% strength by weight aqueous hydrogen peroxide solution was added with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 43.8 gr of demineralised water, 0.4 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 100 gr of Acrylonitrile, 80 gr of n-Butyl acrylate, 20 gr of 2-Ethyl hexyl acrylate (no terpinolene) were added at constant rate for 165 mins. Simultaneously the initiator feed 49.68 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it was cooled down to 60 C. After 5.03 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then mixed for 15 min, followed by adding 5.1 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. 2.58 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 1.23 gr defoamer (Afranil T available from BASF) and then added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 94.1% and a particle size of 101 nm.

Comparative Example 4 (Patent EP 0276 770 B2 Date 22 Jan. 88)

[0097] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 163.51 gr of cationic Potato starch (DS=0.045) was dispersed in 1010 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 0.32 gr of 25% concentration by weight aqueous calcium acetate solution and 32 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45 min of stirring. After further 30 minutes, the enzymatic starch degradation was stopped by adding 30.38 gr of glacial acetic acid solution. After the addition of 6.41 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 8.48 gr of an 10% strength by weight aqueous hydrogen peroxide solution was allowed to run with stirring for 15 min. The reaction temperature is further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 100.0 gr of demineralised water, 1.0 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 298.5 gr of acrylonitrile, 366.38 gr of n-Butyl acrylate were added for 165 min. Simultaneously the initiator feed 88.12 gr of 10% strength by weight aqueous hydrogen peroxide solution was added over 215 min. After the end of metering, the reaction mixture was stirred for another 60 minutes at 85 C. and then it is cooled down to 60 C. After 2.53 gr TBHP (tertiary butyl hydro peroxide) (10%) were added for 30 minute the reaction mixture was mixed for 15 min, followed by adding 5.0 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 10 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. 7.2 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 0.25 defoamer (Afranil T from BASF) were then added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 91.8% and a particle size of 120 nm.

Comparative Example 5 (Corresponding to Example 1 According to US Patent 2009/0139675)

[0098] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 104.9 gr of cationic Potato starch (DS=0.065-0.07) was dispersed in 395 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 1.16 gr of 25% concentration by weight aqueous calcium acetate solution and 11.6 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45 min of stirring. After further 30 minutes, the enzymatic starch degradation was stopped by adding 5.9 gr of glacial acetic acid solution. After the addition of 1.14 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 5.28 gr of an 18% strength by weight aqueous hydrogen peroxide solution was added to the reaction mixture with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 90.0 gr of demineralised water, 0.2 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 140 gr of styrene and 60 gr of n-Butyl acrylate were added at constant rate for 120 mins. Simultaneously the initiator feed 46.11 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 150 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. After 6.20 gr of 10% strength TBHP (tertiary butyl hydro peroxide) was added for 30 minute and then mixed for 30 min. following this 8.20 gr TBHP (10%) was added over 30 min. Thereafter the reaction mixture was cooled down to room temperature. 0.95 gr EDTA (40%) was added and the pH was adjusted to 6 by addition of 15.63 gr NaOH (25%). After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 94.6% and an average particle size (Dz) 81 nm.

Comparative Example 6 (Corresponding to Example 3 According to Example EP-B-1 056 783)

[0099] In a polymerization vessel which was equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 78.1 gr of oxidative degraded potato starch (Perfectamyl A4692 from Avebe) was dispersed in 500 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 1.16 gr of 25% concentration by weight aqueous calcium acetate solution and 11.6 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45 min of stirring. After further 30 minutes, the enzymatic starch degradation was stopped by adding 5.9 gr of glacial acetic acid solution. After the addition of 27 gr of a 1% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 73 gr of an 3% strength by weight aqueous hydrogen peroxide solution was added to the mixture with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 90.0 gr of demineralised water, 0.2 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 104 gr of styrene, 42.6 gr of n-Butyl acrylate, 42.6 gr of t-Butyl acrylate, and 10.6 acrylic acid which were added at constant rate for 120 mins. Simultaneously the initiator feed 59 gr of 3% strength by weight aqueous hydrogen peroxide solution was added for 150 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. After 0.75 gr of 70% strength TBHP (tertiary butyl hydro peroxide) was added for 30 minute and then mixed for 30 min and the pH was adjusted to 6.5 using ammonia. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 24.1% and LD (0.01%) of 90.1% and an average particle size (Dz) 85 nm.

[0100] The application test work was carried out on liner paper by passing the liner paper through the size press containing the respective compositions of the examples as sizing solutions. The respective sizing solution was used to wet size the liner paper and was dried using the drying calendar at a temperature of 120 C. Afterwards, the size of paper was put in a conditioning humidity room for at least eight hours before making the Cobb measurement. The results are presented in Table 3.

TABLE-US-00003 TABLE 3 Application Test on Liner Paper Blank Ex4 Ex5 Ex6 Comp4 Comp5 Comp6 Concentration 6 6 6 6 6 6 6 of Tapioca Starch (%) PSA Dosage 0 1.5 2.5 1.5 2.5 1.5 2.5 1.5 2.5 1.5 2.5 1.5 2.5 (g/l) Cobb60 128 59 32 55 30 69 41 73 49 115 101 105 89 (g/m2)

TABLE-US-00004 TABLE 4 Application Test on Liner Paper Blank Ex4 Ex5 Ex6 Comp4 Comp5 Comp6 Concentration 6 6 6 6 6 6 6 of Tapioca Starch (%) Alun (g/l) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 PSA Dosage 0 1.5 2.5 1.5 2.5 1.5 2.5 1.5 2.5 1.5 2.5 1.5 2.5 (g/l) Cobb60 131 30 23 32 23 45 29 72 41 92 80 87 68 (g/m2)

TABLE-US-00005 TABLE 5 Application Test on Semi-sized wood free paper Blank Ex4 Comp4 Comp5 Concentration 6 6 6 6 of Tapioca Starch (%) PSA Dosage 0 0.5 1.0 0.5 1.0 0.5 1.0 (g/l) Cobb60 104 59 32 68 50 69 41 (g/m2)

[0101] For determining the degree of sizing of the surface-sized papers, the Cobb.sub.60 value according to DIN EN 20 535 was determined. The water absorbing of the paper sheet in g/m.sup.2 after contact with water and a contact time of 60 s is defined as the Cobb.sub.60 value. The lower the Cobb.sub.60 value, the better is the sizing effect of the dispersion used.

EXAMPLE 7

[0102] In a polymerization vessel which equipped with a stirrer, reflux condenser, jacket heating and metering apparatus, 98.56 gr of cationic tapioca starch, Ehcat 69 (DS=0.060-0.070) were dispersed in 438 gr of demineralised water under nitrogen atmosphere and with stirring. Thereafter, 0.38 gr of 25% concentration by weight aqueous calcium acetate solution and 5.6 gr of 1% aqueous solution of commercially available -amylase (Termamyl 120L from Novo Nordisk) were added and the mixture was heated to 85 C. in the course of 45-50 min of stirring. At a temperature of 85 C., 8.59 gr of -amylase (Termamyl 120L) was charged into the vessel and mixed for 30 min. The enzymatic starch degradation was stopped by adding 8.6 gr of glacial acetic acid solution. After the addition of 1.95 gr of a 10% strength by weight aqueous iron II sulfate solution (FeSO4.7H2O), 5.6 gr of an 18% strength by weight aqueous hydrogen peroxide solution was added to the mixture with stirring for 15 min. The reaction temperature was further maintained at 85 C. Afterwards, the feeding of monomer and initiator was started simultaneously. The monomer emulsion mixture consisted of 43.8 gr of demineralised water, 0.4 gr of a 40% strength by weight aqueous solution of sodium alkane sulfonate (K30 from Bayer AG), 100 gr of Acrylonitrile, 40 gr of n-Butyl acrylate, 60 gr of tert-Butyl acrylate and 1.18 gr terpinolene were added at constant rate for 165 mins. Simultaneously the initiator feed 49.68 gr of 18% strength by weight aqueous hydrogen peroxide solution was added for 195 min. After the end of metering, the reaction mixture was stirred for another 30 minutes at 85 C. and then it is cooled down to 60 C. Subsequently 5.03 gr TBHP (tertiary butyl hydro peroxide) (10%) was added for 30 minute and then mixed for 15 min, followed by adding 5.1 gr Rongalit C (sodium formaldehyde sulfoxylate available from Wuxi Yuanhui Chemical Company Limited) (10%) for 60 min and then mixing it for 30 mins. Thereafter the reaction mixture was cooled down to room temperature. 2.58 gr biocide (Acticid MBS from Thor Specialty Chemical Company) and 1.23 gr defoamer (Afranil T available from BASF) were then added. After filtration (125 m), a finely divided dispersion was obtained having a solids content of 30% and LD (0.01%) of 96.6% and a particle size of 89.7 nm.

[0103] The application test work was carried out on liner paper by passing the liner paper through the size press containing the respective compositions of the examples as sizing solutions. The respective sizing solution was used to wet size the liner paper and was dried using the drying calendar at a temperature of 120 C. Afterwards, the size of paper was put in a conditioning humidity room for at least eight hours before making the Cobb measurement. The results are presented in Table 3.

TABLE-US-00006 TABLE 6 Application Test on Liner Paper Blank Ex4 Ex7 Concentration of Tapioca 6 6 6 Starch (%) PSA Dosage (g/l) 0 2.0 3.0 2.0 3.0 Cobb60 (g/m2) 133 62 35 63 32

TABLE-US-00007 TABLE 7 Application Test on Liner Paper Blank Ex4 Ex7 Concentration of Tapioca 6 6 6 Starch (%) Alun (g/l) 1.0 1.0 1.0 PSA Dosage (g/l) 0 1.0 2.0 1.0 2.0 Cobb60 (g/m2) 133 39 23 35 22

[0104] For determining the degree of sizing of the surface-sized papers, the Cobb.sub.60 value according to DIN EN 20 535 was determined. The water absorbing of the paper sheet in g/m.sup.2 after contact with water and a contact time of 60 s is defined as the Cobb.sub.60 value. The lower the Cobb.sub.60 value, the better is the sizing effect of the dispersion used.

EXAMPLE 8

[0105] 24 finely divided polymer dispersions were prepared by a method and analogous to Example 1 using cationic tapioca starch of different degrees of substitution: Ehcat 35 from EMS (DS=0.035-0.040), Ehcat 50 from EMS (DS=0.050-0.055), and Ehcat 69 from EMS (DS=0.060-0.070). Tables 8-13 indicate the dose of the respective cationic tapioca starch; the amount of alum (where this is included in the dispersion); the viscosity and pH of the respective dispersion.

[0106] The application test work was carried out on liner paper by passing the liner paper through the size press containing the respective compositions of the examples as sizing solutions. The respective sizing solution was used to wet size the liner paper and was dried using the drying calendar at a temperature of 120 C. Afterwards, the size of paper was put in a conditioning humidity room for at least eight hours before making the Cobb 60 measurement. The results are presented in Table 8-13.

TABLE-US-00008 TABLE 8 Test Blank 1 2 3 4 Concentration of Excel % 6 6 6 6 6 Size 22 starch Solution Ehcat 35 DS g/L 0 1.5 2.0 3.0 4.0 0.035-0.040 pH 7.51 6.05 5.82 5.51 5.32 Viscosity m .Math. 17 17 17 17 17 Pa .Math. S Pick up % 5.31 5.22 5.32 5.34 5.32 Cobb 60 g/m2 130 93 76 44 25

TABLE-US-00009 TABLE 9 Test Blank 5 6 7 8 Concentration of Excel % 6 6 6 6 6 Size 22 starch Solution Ehcat 50 DS g/L 0 1.5 2.0 3.0 4.0 0.050-0.055 pH 7.51 5.95 5.69 5.41 5.23 Viscosity m .Math. 17 17 17 17 17 Pa .Math. S Pick up % 5.31 5.36 5.40 5.20 5.14 Cobb 60 g/m2 130 85 65 29 24

TABLE-US-00010 TABLE 10 Test Blank 9 10 11 12 Concentration of Excel % 6 6 6 6 6 Size 22 starch Solution Ehcat 69 DS g/L 0 1.5 2.0 3.0 4.0 0.060-0.070 pH 7.51 5.92 5.73 5.42 5.24 Viscosity m .Math. 17 17 17 17 17 Pa .Math. S Pick up % 5.31 4.98 5.10 5.44 5.30 Cobb 60 g/m2 130 80 62 28 22

TABLE-US-00011 TABLE 11 Test Blank 13 14 15 16 Concentration of Excel % 6 6 6 6 6 Size 22 starch Solution Ehcat 35 DS g/L 0 1.5 2.0 3.0 4.0 0.035-0.040 Alum g/L 1.0 1.0 1.0 1.0 pH 7.51 3.94 3.93 3.92 3.94 Viscosity m .Math. 17 17 17 17 17 Pa .Math. S Pick up % 5.31 5.46 5.14 5.93 5.47 Cobb 60 g/m2 130 51 27 23 20

TABLE-US-00012 TABLE 12 Test Blank 17 18 19 20 Concentration of Excel % 6 6 6 6 6 Size 22 starch Solution Ehcat 50 DS g/L 0 1.5 2.0 3.0 4.0 0.050-0.055 Alum g/L 1.0 1.0 1.0 1.0 pH 7.51 3.95 3.95 3.96 3.95 Viscosity m .Math. 17 17 17 17 17 Pa .Math. S Pick up % 5.31 5.58 5.63 5.50 5.69 Cobb 60 g/m2 130 42 22 21 19

TABLE-US-00013 TABLE 13 Test Blank 21 22 23 24 Concentration of Excel % 6 6 6 6 6 Size 22 starch Solution Ehcat 69 DS g/L 0 1.5 2.0 3.0 4.0 0.065-0.070 Alum g/L 1.0 1.0 1.0 1.0 pH 7.51 5.92 5.73 5.42 5.24 Viscosity m .Math. 17 17 17 17 17 Pa .Math. S Pick up % 5.31 5.18 5.18 5.31 5.53 Cobb 60 g/m2 130 40 25 22 19

[0107] For determining the degree of sizing of the surface-sized papers, the Cobb.sub.60 value according to DIN EN 20 535 was determined. The water absorbing of the paper sheet in g/m.sup.2 after contact with water and a contact time of 60 s is defined as the Cobb.sub.60 value. The lower the Cobb.sub.60 value, the better is the sizing effect of the dispersion used.

[0108] It can be seen from the results presented that the polymer dispersions containing the cationic tapioca starches of different degrees of substitution (DS) provide suitable sizing results. It can be seen that at low doses of cationic tapioca starch i.e. 1.5 or 2.0 g/L the starches with a higher degree of substitution provide relatively better Cobb 60 values than those with the lower degree of substitution. Nevertheless at doses of 3.0 and 4.0 g/L cationic tapioca starch the Cobb 60 values are all very good with less variation observed between the starches of different degrees of substitution.

[0109] Tables 11-13 show that when 1 g/L alum is incorporated into the polymer dispersion in conjunction with the respective cationic starch that improved sizing results are obtained. Although the best overall sizing results can be seen at the doses of 3.0 and 4.0 g/L cationic tapioca starch when the alum is included, the sizing results are significantly improved at the lower doses of 1.5 or 2.0 g/L cationic tapioca starch with 1 g/L alum by comparison to the equivalent dispersions in the absence of alum.