Sizing composition, its use and a method for producing paper, board or the like

Abstract

The invention relates to a composition for sizing of a surface of paper, board or the like and its use for increasing strength properties of paper, board or the like. The composition has a solids content of 3-30%, and it comprises degraded non-ion is starch, and at least 0.5 weight-% of anionic polyacrylamide, which has a molecular weight, MW, >500 000 g/mol and <2 500 000 g/mol and an anionicity in the range of 4-35 mol-%. The invention further relates also to a method for producing paper, board or the like, which comprises addition of a first strength composition, which comprises a cationic agent, to a fibre stock, formation of a fibrous web from the fibre stock, drying of the fibrous web to dryness of at least 60%, and application of a second strength com position, which comprises an anionic hydrophilic polymer and a starch component, on the surface of the fibrous web.

Claims

1. Sizing composition for sizing of a surface of paper, board or the like, the sizing composition having a solids content of 3-30% and comprising degraded non-ionic starch, and at least 0.5 weight-% of anionic polyacrylamide, which has an average molecular weight, MW, >500 000 g/mol and <2 500 000 g/mol, and an anionicity in the range of 4-35 mol-%.

2. Composition according to claim 1, characterised in that the anionic polyacrylamide has the average molecular weight in the range of 530 000-2 000 000 g/mol, preferably 530 000-1 500 000 g/mol, more preferably 650 000-1 400 000 g/mol.

3. Composition according to claim 1 or 2, characterised in that the anionic polyacrylamide has the anionicity in the range of 4-24 mol-%, preferably 4-17 mol-%, more preferably 5-17 mol-%.

4. Composition according to claim 3, characterised in that the anionic polyacrylamide has anionicity in the range of 7-15 mol-%, preferably 9-13 mol-%.

5. Composition according to any of claims 1-4, characterised in that the anionic polyacrylamide is a copolymer of acrylamide and unsaturated carboxylic acid monomers, such as (meth)acrylic acid, maleic acid, crotonic acid, itaconic acid or their mixture.

6. Composition according to any of preceding claims 1-5, characterised in that the composition comprises 0.5-10 weight-%, preferably 0.75-5 weight-%, preferably 1-2.5 weight-%, of anionic polyacrylamide.

7. Composition according to any of preceding claims 1-6, characterised in that the starch is enzyme treated or thermally degraded starch.

8. Composition according to any of preceding claims 1-7, characterised in that the starch, prior to its possible degradation, has an amylose content of 15-30%, preferably 20-30%, more preferably 24-30%.

9. Composition according to any of preceding claims 1-8, characterised in that the composition is free from inorganic mineral fillers or pigments.

10. Use of sizing composition according to any of claims 1-9 for increasing strength properties of paper, board or the like.

11. Use according to claim 10, characterised in that the paper, board or the like comprises recycled fibres.

12. Use according to claim 10 or 11, characterised in that the paper or board is selected from uncoated fine paper, liner, fluting or folding boxboard (FBB).

13. Use according to any of claim 10, 11 or 12, characterised in that the paper or board has an ash content of at least 6%, preferably at least 12%, more preferably at least 15%.

14. Use according to any of preceding claims 10-13, characterised in that the application temperature of the sizing composition is 50-90° C., preferably 65-85° C.

15. Use according to any of preceding claims 10-14, characterised in that the sizing composition is applied 5-80 kg/ton paper as dry, preferably 10-50 kg/ton paper as dry.

16. Method for producing paper, board or the like, which method comprises adding a first strength composition, which comprises a cationic agent, to a fibre stock, forming a fibrous web from the fibre stock, drying the fibrous web to dryness of at least 60%, applying on the surface of the fibrous web a second strength composition, which comprises an anionic hydrophilic polymer and a starch component.

17. Method according to claim 16, characterised in that the cationic agent in the first strength composition comprises cationic starch or at least one cationic synthetic polymer or a mixture of cationic starch and cationic synthetic polymer(s).

18. Method according to claim 17, characterised in that the cationic synthetic polymer is selected from a group comprising copolymers of (meth)acrylamide and cationic monomers; glyoxylated polyacrylamide; polyvinylamine; N-vinyl formamide; copolymer of acrylamide and diallyldimethylammonium chloride (DADMAC); polyamidoamine epihalohydrin and any of their mixtures.

19. Method according to claim 17 or 18, characterised in that the cationic synthetic copolymer is a copolymer originating from >20 mol-% of non-ionic monomers and 3-30 mol-%, preferably 5-20 mol-%, more preferably 6-10 mol-%, of cationic monomers.

20. Method according to claims 17-19, characterised in that the cationic synthetic polymer has an average molecular weight of 200 000-6 000 000 g/mol, preferably 300 000-3 000 000 g/mol, more preferably 500 000-2 000 000 g/mol, even more preferably 600 000-950 000 g/mol.

21. Method according to any of preceding claims 16-20, characterised in that the cationic agent has charge density of 0.05-5 meq/g, preferably 0.1-3 meq/g, more preferably 0.3-2 meq/g, even more preferably 0.5-1.4 meq/g, at pH 7.

22. Method according to any of claims 16-21, characterised in adding the first strength composition to the fibre stock in amount of 0.2-15 kg/ton, preferably 0.4-9 kg/ton produced paper, more preferably 1-5 kg/ton produced paper, calculated as dry product.

23. Method according to any of claims 16-22, characterised in that the second strength composition comprises 0.1-20 weight-%, preferably 0.5-10 weight-%, more preferably 0.7-4 weight-% of anionic hydrophilic polymer, and 80-99.9 weight-%, preferably 90-99 weight-%, more preferably 96-99 weight-% of starch.

24. Method according to claim 16, characterised in that the anionic hydrophilic polymer is a copolymer of (meth)acrylamide and an anionic monomer.

25. Method according to claim 24, characterised in that the anionic monomer is selected from unsaturated mono- or dicarboxylic acids.

26. Method according to any of preceding claims 16-25, characterised in that the anionic hydrophilic polymer of the second strength agent has an average molecular weight of 50 000-8 000 000 g/mol, preferably 150 000-3 000 000 g/mol, more preferably 250 000-1 500 000 g/mol, even more preferably 350 000-950 000 g/mol.

27. Method according to any of preceding claims 16-26, characterised in that the anionic hydrophilic polymer of the second strength agent originates from >20 mol-% of non-ionic monomers and 1-50 mol-%, preferably 2-25 mol-%, more preferably 4-17 mol-%, of anionic monomers.

28. Method according to any of preceding claims 16-27, characterised in that the fibre stock comprises at least 10-30%, more preferably 11-19% of inorganic mineral filler, measured by ash content at 525° C.

29. Method according to any of preceding claims 16-28, characterised in that the fibre stock comprises at least 20 weight-%, preferably at least 50 weight-%, of fibres originating from recycled paper or board.

30. Method according to any of claims 16-29, characterised in applying the second strength composition on the fibre web in such amount that the anionic hydrophilic polymer is applied on the web in amount of 0.1-5 kg/t, preferably 0.2-3 kg/t, more preferably 0.5-2 kg/t.

Description

EXAMPLE 1

General Procedure for Synthesis of Anionic Polyacrylamide Solution

[0085] Anionic polyacrylamides were synthesized by radical polymerization using the following general procedure. Prior to polymerization monomer mixture was prepared in a monomer tank by mixing all monomers (including possible cross-linker monomers), water, Na-salt of EDTA and sodium hydroxide. This mixture is called hereafter “Monomer mixture”. The monomer mixture was purged with nitrogen gas for 15 min.

[0086] Catalyst solution was made in a catalyst tank by mixing water and ammonium persulfate. The mixture is called hereafter “Catalyst solution” and it was made less than 30 min before use.

[0087] Water was added into a polymerization reactor equipped with mixer and a jacket for heating and/or cooling. The water was purged with nitrogen gas for 15 min. The water was heated to 100° C. Both “Monomer mixture” and “Catalyst solution” feeds were started at the same time. Feed time for “Monomer mixture” was 90 min and for “Catalyst solution” 100 min. When the feed of “Catalyst solution” was completed, the mixture in the polymerization reactor was mixed for 45 min. The mixture was cooled to 30° C. and then the aqueous polymer solution was removed from the reactor.

[0088] The following characteristics were analyzed for the obtained aqueous polymer solution. Dry solids content was analyzed by using Mettler Toledo HR73, at 150° C. Viscosity was analyzed by Brookfield DVI+, equipped with small sample adapter, at 25° C., using spindle S18 for solutions with viscosity <500 mPas and spindle S31 for solutions, with viscosity 500 mPas or higher, and using the highest feasible rotation speed for the spindle. pH of the solution was analyzed by using calibrated pH-meter.

EXAMPLE 2

Synthesis of Test Polymer AC17HM Synthesis of test polymer AC17HM is described as a production example in detail.

[0089] Prior to the polymerization a monomer mixture was prepared in a monomer tank by mixing 42.4 g of water, 188 g of 50% aqueous solution of acrylamide, 19.5 g acrylic acid, 0.59 g of 39% aqueous solution of Na-salt of EDTA and 10.8 g of 50% aqueous solution sodium hydroxide. Monomer mixture was purged with nitrogen gas for 15 min.

[0090] A catalyst solution was prepared in a catalyst tank by mixing 27 g water and 0.08 g ammonium persulfate.

[0091] 440 g of water was added in a polymerization reactor. The polymerization was performed as described above in Example 1.

[0092] The following characteristics were determined form test product AC17HM: dry solids content 15.1%, viscosity 7700 mPas, pH 5.1. The polymer solution was diluted with water to concentration of 10%. Viscosity of the diluted polymer solution was 1200 mPas.

EXAMPLE 3

Size Press Test

[0093] Preparation of Surface Size Compositions

[0094] A 15 weight-% solution of dextrinated surface size starch (C*Film 07311, Cargill) is cooked for 30 min at 95° C. The starch was selected to simulate enzymatically degraded native starch. Surface size compositions are prepared by mixing of water, starch and used chemicals, in this order. This means that anionic polyacrylamide and 1 weight-% cationic acrylate based hydrophobisation agent (Fennosize S3000, Kemira Oyj), calculated as dry, was added to the cooked surface size starch solution, and mixed at 70° C., for at least 2 min. Starch, the used anionic polyacrylamides and their amounts in weigh-%, calculated as dry, are listed in Table 3. Viscosity of the obtained composition was measured by using Brookfield Visco cP, Spindle 18, 100 rpm, 60° C., at 9% concentration. The surface size compositions were stored at 70° C. until surface sizing experiments were carried out.

[0095] Surface Sizing Experiments

[0096] Size press parameters were as follows:

[0097] Size press manufacturer: Werner Mathis AG, CH 8155 Niederhasli/Zürich; Size press model: HF 47693 Type 350; Operation speed: 2 m/min; Operation pressure: 1 bar; Operation temperature: 60° C.; Sizing solution volume: 140 ml/test; Sizing times/sheet: 2.

[0098] Sizing is performed in machine direction and the surface size composition is applied as 12 weight-% solution.

[0099] Base paper was Schrenz paper, 100 g/m.sup.2, 100% recycled fibre based liner grade without size press. The base paper had an ash content of 16.4% (standard ISO 1762, temperature 525° C.) and bulk value 1.57 cm.sup.3/g (measured with standard ISO 534).

[0100] Drying of the sized sheets was made in one-cylinder felted steam heated dryer drum at 95° C. for 1 min. Shrinkage was restricted in dryer.

[0101] The test samples are sized twice, and the properties of the sized sheets are measured. The used measurements, testing devices and standards are given in Table 4.

[0102] The measured results after one pass are given in Table 5 and after two pass in Table 6. The percentage values for pick-up in Table 5 and 6 are calculated from weight increase of an air-conditioned sheet, where the basis weight of the sheet is measured before and after sizing. The percentage values for starch saving in Table 5 and 6 are calculated as the ratio of the pick-up value of an individual test sample and the pick-up value of the reference. The indexed values in Table 5 and 6 are given as the strength divided by the basis weight of the paper/board. The geometric (GM) value is the square root of (MD value)*(CD value). MD value is the measured strength value in machine direction and CD value is the measured strength value in machine cross direction.

[0103] It can be seen from results in Table 5 for test samples 2 and 6, where the amount of the polymer in the sizing composition was 2.5% that after one pass the obtained values for SCT GM index and CMT30 index are clearly improved when they are compared to comparative test sample 4 with the same polymer content. When improvements in strength results are obtained even at low polymer dosage the overall process economy is improved.

[0104] Furthermore, it can be seen from results in Table 5 for test samples 3 and 7, where the amount of the polymer in the sizing composition was 7.5%, that the obtained values for SCT GM index, burst Index and CMT30 index are similar or improved when they are compared to comparative test sample 5 with the same polymer content. Clear and unexpected improvement can be seen in the obtained Cobb60 values, which indicates that the compositions according to the present invention gave better hydrophobication effect. Further, higher dry content and higher starch savings could be obtained.

[0105] The results after two pass are given in Table 6. The results are similar to those in given in Table 5. This means that improvements for test samples 2 and 6 in obtained values for SCT GM index and CMT30 index can be observed when they are compared to comparative test sample 4. Similarly, it can be seen from results in Table 6 for test samples 3 and 7 that the obtained values for SCT GM index, burst Index and CMT30 index are similar or improved when they are compared to comparative test sample 5 with the same polymer content. Clear improvements are again seen in the obtained Cobb60 values, as well as dry content and starch savings.

EXAMPLE 4

Size Press Test

[0106] The surface sizing compositions are prepared in the same manner as in Example 3.

[0107] The surface sizing experiments are carried out in the same manner and using the same base paper as in Example 3, except for following points: [0108] the test samples are sized only once, the sizing volume being 100 ml; [0109] the experiments are carried out for each test sample by sizing both at 6 weight-% and 12 weight-% concentration, in which case the pick-up was about 3% and 5%, respectively. The results for each test sample were calculated linearly to correspond 3.5% pick-up.

[0110] The results of Example 4 are given in Table 7. The indexed values are calculated in the same manner than in Example 3.

[0111] It can be seen from Table 7 that the surface size compositions according to the present invention provide simultaneous improvement, i.e. increase, in SCT GM Index and burst index. Furthermore, it can be observed that for test sample 16 the CMT30 index is clearly improved, even if the polymer content in the size composition is only 2.5%.

[0112] Further, from Table 7 it could be anticipated that the surface size compositions comprising polymer with higher molecular weight have especially good performance results. It is speculated that low level of cross-linking or no cross-linking of the polymer might be beneficial for the performance.

EXAMPLE 5

Size Press Test

[0113] The surface sizing compositions are prepared in the same manner as in Example 3, except that no hydrophobisation agent was used.

[0114] The surface sizing experiments are carried out in the same manner and using the same base paper as in Example 3, except that the test samples are sized only once, the sizing volume being 100 ml.

[0115] Starch, the used anionic polyacrylamides and their amounts in weigh-%, calculated as dry, are listed in Table 8. The results of Example 5 are shown in Table 9. The pick-up values and the indexed values are calculated in the same manner than in Example 3.

[0116] It can be seen from Table 9 that even if some improvement in SCT GM index and burst strength index can be observed for all the used surface size compositions, the improvement was more pronounced when the composition comprised polymer with higher anionicity, see the test samples 2 and 3 of Table 9.

EXAMPLE 6

Size Press Test

[0117] The surface sizing compositions are prepared in the same manner as in Example 3, except that no hydrophobisation agent was used and the surface starch used was Stabilys A020 (Roquette, France).

[0118] The surface sizing experiments are carried out in the same manner and using the same base paper as in Example 3, except for the following points: [0119] the surface size composition was applied as 9 weight-% solution, [0120] the applicator rolls of the sizing apparatus were heated in 82° C. water bath.

[0121] Starch, the used anionic polyacrylamides and their amounts in weigh-%, calculated as dry, are listed in Table 10. The results of Example 6 are shown in Table 11. The pick-up values and indexed values are calculated in the same manner than in Example 3.

[0122] It can be seen from Table 11 that when the surface size composition comprises polymer with too low molecular weight (Test sample 2) or polymer with too high molecular weight (Test samples 3 and 4) the simultaneous improvement of both SCT GM index and burst index is not achieved.

EXAMPLE 7

Size Press Test

[0123] The surface sizing compositions are prepared in the same manner as in Example 3. Hydrophobisation agent was used in some of the surface size compositions, see Table 12.

[0124] The surface sizing experiments are carried out in the same manner as in Example 3, except for the following points: [0125] the surface size composition was applied as 9 weight-% solution, [0126] base paper was Schrenz paper, 105 g/m.sup.2, 100% recycled fibre based liner grade without size press. The base paper had an ash content of 15.9% (measured with standard ISO 1762, temperature 525° C.) and bulk value 1.75 cm.sup.3/g (measured with standard ISO 534).

[0127] Starch, the used anionic polyacrylamides and their amounts in weigh-%, calculated as dry, are listed in Table 12. The results of Example 7 are shown in Table 13. The pick-up values and the indexed values are calculated in the same manner than in Example 3.

[0128] It can be seen from Table 13 that the size compositions according to the present invention comprising polymers with higher molecular weight and anionicity than the polymer, which was used in comparative the surface size of test samples, provide better SCT strength and similar or better burst strength, when the polymer amounts in the surface size compositions are taken into account. Furthermore, it can be observed that the surface size composition of test sample 9 could provide an improved strength properties even if it comprised hydrophobisation agent.

EXAMPLE 8

[0129] Commercial Central European Old Corrugated Container (OCC) stock from Central Europe was used as raw material in Example 8.

[0130] OCC was disintegrated from bales with mill water to achieve consistency of 2.3% for the test stock suspension. Disintegration was performed by using Andritz laboratory refiner for 35 minutes with open fillings, i.e. refiner blades were open in order to avoid refining effect. The properties of the disintegrated OCC stock and the mill water used are given in Table 14.

[0131] Papermaking agents and compositions used in Example 8 are given in Table 15. The molecular weights in Table 15 are measured by using gel permeation chromatography employing size exclusion chromatographic columns with polyethylene oxide (PEO) calibration, if not otherwise indicated.

[0132] The used papermaking agents and compositions were dosed into the disintegrated OCC stock. Fresh mill water was used as process water, which was fed into a mixing tank with the disintegrated OCC stock under agitation. Thus the stock was diluted to headbox consistency of 1% with the fresh mill water.

[0133] The diluted stock suspension was fed to a headbox of a pilot paper machine. A retention polymer and colloidal silica were used as retention aids. Retention polymer was added before the headbox pump of the pilot paper machine, and the colloidal silica was dosed before the headbox of the pilot paper machine. The used retention polymer was a cationic copolymer of acrylamide, molecular weight about 6,000,000 g/mol, charge density 10 mol-%. Colloidal silica had an average particle size of 5 nm. Retention polymer dosage was 100 g/ton of dry product, and colloidal silica dosage was 200 g/ton of dry product

[0134] OCC liner and fluting sheets having basis weight of 100 g/m.sup.2 were produced on a pilot paper machine. Operational parameters of the pilot paper machine were as follows:

[0135] Running speed: 2 m/min; Web width: 0.32 m; Rotation speed of the holey roll: 120 rpm; Press section: 2 nips; Drying section: 8 pre-drying cylinders, baby cylinder, 5 drying cylinders.

[0136] After the manufacture, the sheets were size pressed with dextrinated starch C*film 07311 (Cargill). This degraded starch simulates enzymatically degraded native starch. Sizing amount was 50 kg/t dry. Size press parameters were as follows:

[0137] Size press manufacturer: Werner Mathis AG, CH 8155 Niederhasli/Zürich; Size press model: HF 49895; Operation speed: 3 m/min; Operation pressure: 1.5 bar; Operation temperature: 70° C.; Sizing solution volume: 300 ml; Sizing times/sheet: 2. Drying of the sized sheets was done in one-cylinder felted steam heated dryer drum at 93° C. for 2 min. Shrinkage was restricted in dryer.

[0138] Before testing of the strength properties of the produced liner sheets, they were pre-conditioned for 24 h at 23° C. in 50% relative humidity according to standard ISO 187. Devices and standards, which were used to measure the properties of the sheets, are given in Table 4, except for SCT, where Lorentzen & Wettre Compression Strength tester was used, according to standard ISO 9895.

[0139] The results for strength property tests are given in Table 16. The results in Table 16 are indexed: obtained burst strength and SCT measurement values are indexed by dividing each obtained measurement value by basis weight of the measured sheet. SCT strength was then calculated as geometrical mean of machine direction strength and cross direction strength.

[0140] From the results of Table 16 it can be seen that both the burst strength and SCT strength are clearly improved when the method according to the present invention is used, i.e. a first strength composition comprising at least one cationic agent is added to the pulp and a second strength composition which comprises anionic hydrophilic polymer is applied on the sheet surface. The combination according to second aspect of the invention, i.e. the first strength composition added before second strength composition, makes it possible to reduce the amount of anionic hydrophilic polymer, which is applied on the surface of the fibrous web, while obtaining similar or higher strength properties.

EXAMPLE 9

[0141] Example 9 was performed in the same manner and by using the same raw materials, papermaking agents and compositions and test methods as Example 8. Basis weight of the produced base paper was 110 g/m.sup.2.

[0142] The results for strength property tests of Example 9 are given in Table 17.

[0143] It can be seen from results in Table 17 that the sheets prepared according to the second aspect of the present invention show similar or even improved burst index values as the reference samples. It should be noted that all sheets prepared according to the second aspect of the present invention show lower size pick values. This means that the similar or even better burst index values are obtained by using lower amounts of size, which gives considerable savings in material used.

[0144] Even if the invention was described with reference to what at present seems to be the most practical and preferred embodiments, it is appreciated that the invention shall not be limited to the embodiments described above, but the invention is intended to cover also different modifications and equivalent technical solutions within the scope of the enclosed claims.

TABLE-US-00001 TABLE 1 Anionic polyacrylamides, dry polymers, which are used in Examples 3-7. Molecular Weight, Anionicity Ubbelohde Abbreviation Remark [mol-%] [Mg/mol] LMA-V-2 12.5 1.4 LK4358/1 comparative 5 2.7

TABLE-US-00002 TABLE 2 Anionic polyacrylamides, solution polymers, which are used in Examples 3-7. Cross- linker Molecular [mol-%, Anionicity Viscosity Weight of total Abbreviation Remark [mol-%] [mPas] [Mg/mol] monomers] AC8H 8 4300 0.5 — AC8M compar- 8 300 0.44 — ative AC8L compar- 8 83 0.34 — ative AC20H 20 9560 0.71 — AC20M compar- 20 360 0.46 — ative AC20L compar- 20 70 0.33 — ative AC32H 32 4400 0.65 — AC32M compar- 32 236 0.42 — ative AC32L compar- 32 63 0.32 — ative AC13HM 12.5 1170 0.55 — AC4H 4 6400 0.68 — AC17HM 17 1200 0.55 — AC8H-CL2 8 9940 0.71 0.018 AC20M-CL1 compar- 20 194 0.41 0.030 ative AC11HM 11 1070 0.54 —

TABLE-US-00003 TABLE 3 Anionic polyacrylamides and their amounts in weigh-% for Example 3. Test Composition Sample Starch Polymer Viscosity # Remark [%] Polymer/ [%] [mPas] 1 reference 99 — 0 3.2 2 96.5 AC8H 2.5 7.9 3 91.5 AC8H 7.5 18.9 4 comparative 96.5 AC8M 2.5 5.8 5 comparative 91.5 AC8M 7.5 11.2 6 96.5 AC13HM 2.5 8.2 7 91.5 AC13HM 7.5 21.7

TABLE-US-00004 TABLE 4 Sheet testing devices and standards used. Measurement Device Standard Basis weight Mettler Toledo ISO 536 SCT GM Index Lorentzen & Wettre ISO 9895 (Short Span Compression Strength tester Compression test) Burst strength IDM Test EM-50/80 ISO 2758 CMT30 Index Sumet-Messtechnik SC-500 ISO 7263: 1994 Fluter: PTA Group AV-S Cobb60 — ISO 535

TABLE-US-00005 TABLE 5 The measured results after one pass in Example 3. Test Penetrated Starch Sample Polymer Pick-up SCT GM Index Burst Index CMT30 Index Cobb60 Dry content saving # Remark [kg/t dry] [%] [Nm/g] [kPam.sup.2/g] [Nm.sup.2/g] [g/m]2 [%]* [%] 1 ref. 0 4.2 23.8 1.98 1.29 106 74 0 2 1.0 3.8 24.1 2.12 1.25 90 76 8.6 3 2.7 3.6 24.5 2.06 1.28 80 77 15.0 4 comp. 1.0 3.9 23.6 2.12 1.24 97 75 6.9 5 comp. 2.8 3.7 24.1 2.10 1.29 100 76 11.0 6 0.9 3.4 24.3 2.11 1.28 93 78 17.9 7 2.3 3.1 24.7 2.21 1.29 83 80 26.5 *dry content after size press

TABLE-US-00006 TABLE 6 The measured results after two passes in Example 3. Test Penetrated Starch Sample Polymer Pick-up SCT GM Index Burst Index CMT30 Index Cobb30 Dry content saving # Remark [kg/t dry] [%] [Nm/g] [kPam.sup.2/g] [Nm.sup.2/g] [g/m]2 [%]* [%] 1 ref. 0 7.0 25.2 2.01 1.36 93 63 0 2 1.6 6.3 26.8 2.22 1.47 30 66 12.7 3 4.5 6.0 27.3 2.28 1.48 25 67 21.8 4 comp. 1.6 6.5 25.8 2.07 1.40 58 65 10.6 5 comp. 4.7 6.3 26.5 2.30 1.49 40 66 17.8 6 1.5 5.9 26.6 2.20 1.45 26 67 18.8 7 4.1 5.4 27.6 2.45 1.51 27 69 28.6 *dry content after size press

TABLE-US-00007 TABLE 7 Results of Example 4. Test Sample Starch Polymer Viscosity SCT GM Index* Burst Index* CMT30 Index* # Remark Polymer [%] [%] [mPas] [%] [%] [%] 1 reference — 100 0 4 0 0 0 2 AC20H 97.5 2.5 28 3.3 5.3 4.5 3 AC20H 92.5 7.5 65 4.5 9.0 4.3 4 comparative AC32M 97.5 2.5 10 1.0 6.9 4.0 5 comparative AC32M 92.5 7.5 21 2.8 11.0 5.8 6 comparative AC20M 97.5 2.5 15 3.8 3.0 0.5 7 comparative AC20M 92.5 7.5 28 4.3 6.0 4.9 8 comparative AC8M 97.5 2.5 8 −0.8 4.7 2.1 9 comparative AC8M 92.5 7.5 15 5.6 5.4 5.4 10 comparative AC20L 97.5 2.5 9 3.0 −1.5 5.0 11 comparative AC20L 92.5 7.5 15 4.5 5.7 1.5 12 comparative AC20M-CL1 97.5 2.5 14 2.6 0.9 2.6 13 comparative AC20M-CL1 92.5 7.5 27 4.7 4.4 4.0 14 AC32H 97.5 2.5 28 2.4 4.5 4.8 15 AC32H 92.5 7.5 72 5.7 8.9 2.9 16 AC8H 97.5 2.5 15 4.2 8.0 5.3 17 AC8H 92.5 7.5 33 8.7 13.8 5.6 18 comparative AC8L 97.5 2.5 7 2.3 0.5 1.7 19 comparative AC8L 92.5 7.5 11 5.3 10.6 4.2 20 AC8H-CL2 97.5 2.5 15 4.3 7.0 −0.8 21 AC8H-CL2 92.5 7.5 31 7.4 13.1 3.6 *values are given as increase %, calculated from the values for the reference

TABLE-US-00008 TABLE 8 Anionic polyacrylamides and their amounts in weigh-% for Example 5. Test Composition Sample Starch Polymer Viscosity # Remark [%] Polymer [%] [mPas] 1 reference 100 — 0 3.5 2 97.5 AC13HM 2.5 12.1 3 92.5 AC13HM 7.5 27.1 4 97.5 AC4H 2.5 8 5 92.5 AC4H 7.5 17.4

TABLE-US-00009 TABLE 9 Results of Example 5. Test Penetrated SCT GM Index Burst Index Dry Sample Polymer Pick-up increase* increase* content* # Remark [kg/t dry] [%] [%] [%] [%] 1 reference 0.0 3.8 0.0 0.0 76 2 0.9 3.4 3.7 4.6 78 3 2.4 3.3 2.4 9.2 79 4 0.8 3.3 1.1 1.5 79 5 2.4 3.2 1.9 4.3 79 *values are given as increase %, calculated from the values for the reference

TABLE-US-00010 TABLE 10 Anionic polyacrylamides and their amounts in weigh-% for Example 6. Test Composition Sample Starch Polymer Viscosity # Remark [%] Polymer/ [%] [mPas] 1 reference 100 — — 7.25 2 comparative 97.5 AC8M 2.5 12.6 3 comparative 99 LK4358/1 1 22.3 4 comparative 97.5 LK4358/1 2.5 31.2 5 97.5 AC13HM 2.5 20.9

TABLE-US-00011 TABLE 11 Results of Example 6. Test Penetrated Pick- SCT GM Burst Sample Polymer up Index Index # Remark [kg/t dry] [%] [Nm/g] [kPam.sup.2/g] 1 reference 0 3.8 25.9 2.3 2 comparative 0.9 3.7 25.9 2.3 3 comparative 0.4 4.3 24.8 2.2 4 comparative 1.1 4.3 24.3 2.2 5 0.9 3.6 26.1 2.4

TABLE-US-00012 TABLE 12 Anionic polyacrylamides and their amounts in weigh-% for Example 7. Test Hydrophob. Sample Starch Agent Polymer Viscosity # Remark [%] [%] Polymer [%] [mPas] 1 ref. 100 — — — 7.25 2 comp. 97.5 — AC8M 2.5 12.6 3 comp. 95 — AC8M 5 22.3 4 97.5 — AC11HM 2.5 31.2 5 95 — AC11HM 5 20.9 6 97.5 — LMA-V-2 2.5 20.9 7 95 — LMA-V-2 5 20.9 8 ref. 99 1 — — 20.9 9 96.5 1 AC11HM 2.5 20.9

TABLE-US-00013 TABLE 13 Results of Example 7. Test Penetrated Pick- SCT GM Burst Sample Polymer up Index Index # Remark [kg/t dry] [%] [Nm/g] [kPam.sup.2/g] 1 reference 0.0 9.2 22.9 1.96 2 comparative 2.3 9.4 23.3 2.10 3 comparative 4.5 9.0 23.7 2.13 4 2.4 9.4 24.0 2.11 5 4.5 9.0 24.1 2.13 6 2.3 9.2 23.7 2.06 7 4.5 8.9 25.2 2.26 8 reference 0.0 8.9 22.6 1.98 9 2.2 8.8 23.1 2.03

TABLE-US-00014 TABLE 14 Characteristics of disintegrated OCC stock and mill water used in Example 8. Disintegrated Mill Device/standard used Characteristic OCC stock water for measurement pH — 7.5 Knick Portamess 911 Conductivity 1.9 2.5 Knick Portamess 911 Charge (μeq/l) −262 −283 Mütek PCD 03 Zeta potential (mV) −8.7 — Mütek SZP-06 Consistency (g/l) 23 — ISO 4119 Ca-content (mg/l) — 643 ISO 777 Alkanity (mmol/l) — 2.2 ISO 9963 COD (mg/l) 1013 630 ISO 6060

TABLE-US-00015 TABLE 15 Papermaking agents and compositions used in Example 1. Charge Molecular at pH 7, Weight, Abbreviation Agent/Composition meq/g dry 10.sup.6 g/mol Comment STA Cationic waxy starch 0.4 Cooked starch STA2 Cationic potato starch 0.2 Cooked starch CPAM1 Copolymer of acrylamide- 1.3 ~0.8 Cationic polymer acryloyloxyethyltrimethyl ammoniumchloride (ADAM-Cl) GPAM Copolymer of glyoxylated 2 ~0.4 Cationic acrylamide and DADMAC crosslinked polymer APAM1 Copolymer of acrylamide and −1.1 ~0.5 Anionic polymer acrylic acid APAM2 MBA copolymer of acryl- −2.8 ~0.5 Anionic amide and acrylic acid** crosslinked polymer *The degree of hydrolysis is 40 mol-%. Active polymer content is 74%. The percentage of hydrolysis degree gives the amount of monomers having amine functionality in their structure. **crosslinker: methylenebisacrylamide (MBA) 600 ppm of monomers

TABLE-US-00016 TABLE 16 Results of strength property tests of Example 8. Pulp Size Additive Additive SCT Dose Size Dose Geom. ind. Burst index Pulp Additive [kg/ton] Additive [kg/ton] [kNm/kg] [kPam.sup.2/g] — — — — 22.4 2.15 — — APAM1 2.8 23.6 2.21 — — APAM1 5.7 26.1 2.53 CPAM + STA 0.5 + 0.5 — — 24.5 2.17 CPAM + STA 0.5 + 0.5 APAM1 2.7 26.4 2.57 CPAM + STA 0.5 + 0.5 APAM1 5.4 28.1 2.49

TABLE-US-00017 TABLE 17 Results of strength property tests of Example 9. Pulp Size Additive Additive Size pick Burst Pulp Dose Size Dose up index Additive [kg/ton] Additive [kg/ton] [%] [kPam.sup.2/g] Comment STA2 10 — — 6.8 2.8 Reference STA2 10 APAM1 3.2 6.4 3.1 Good STA2 10 APAM1 5.9 5.9 3.1 Good GPAM 1 — 7.9 2.9 Reference GPAM 1 APAM1 3.8 7.5 2.9 Good GPAM 1 APAM1 7.1 7.1 3.0 Good CPAM1 + 0.5 + 0.5 — — 8.4 3.0 Reference STA CPAM1 + 0.5 + 0.5 APAM2 3.6 7.2 3.1 Good STA CPAM1 + 0.5 + 0.5 APAM2 6.9 6.9 3.2 Good STA