PROCESS FOR THE PRODUCTION OF NANO-FIBRILLAR CELLULOSE SUSPENSIONS

Abstract

The present invention relates to a process for the production of suspensions of nano-fibrillar cellulose by providing cellulose fibres and at least one filler and/or pigment; combining the cellulose fibres and the at least one filler and/or pigment; and fibrillating the cellulose fibres in the presence of at least one filler and/or pigment, as well as the suspensions of nano-fibrillar cellulose obtained by this process and their uses.

Claims

1-24. (canceled)

25. A process for the production of a nano-fibrillar cellulose suspension comprising the steps of: (a) providing cellulose fibres, wherein all or part of the cellulose fibres may be obtained from a recycled pulp; (b) providing at least one filler and/or pigment; (c) combining the cellulose fibres and the at least one filler and/or pigment; and (d) fibrillating the cellulose fibres in an aqueous environment in the presence of the at least one filler and/or pigment in a homogenizer or an ultra-fine friction grinder until a nano-fibrillar cellulose suspension is formed, wherein in step (d) the weight ratio of fibres to the at least one filler and/or pigment on a dry weight basis is from 1:10 to 10:1.

26. The process according to claim 25, wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.2 to 35 wt-%.

27. The process according to claim 25, wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.25 to 10 wt-%.

28. The process according to claim 25, wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 1 to 5 wt-%.

29. The process according to claim 25, wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 2 to 4.5 wt-%.

30. The process according to claim 25, wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 1.3 to 3.5 wt-%.

31. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) is precipitated calcium carbonate.

32. The process according to claim 31, wherein the at least one filler and/or pigment in step (b) is precipitated calcium carbonate having a vateritic, a calcitic or an aragonitic crystal structure.

33. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) is natural ground calcium carbonate.

34. The process according to claim 33, wherein the at least one filler and/or pigment in step (b) is natural ground calcium carbonate selected from marble, limestone and/or chalk.

35. The process according to claim 31, wherein the precipitated calcium carbonate in step (b) is ultrafine discrete prismatic, scalenohedral or rhombohedral precipitated calcium carbonate.

36. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) is in the form of particles having a median particle size of from 0.03 to 15 μm.

37. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) is in the form of particles having a median particle size of from 0.2 to 5 μm.

38. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) is in the form of particles having a median particle size of from 0.2 to 4 μm.

39. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) is in the form of particles having a median particle size of about 1.5 or about 3.2 μm.

40. The process according to claim 25, wherein the at least one filler and/or pigment in step (b) comprises a dispersing agent.

41. The process according to claim 40, wherein the dispersing agent is selected from homopolymers or copolymers of polycarboxylic acids and/or their salts or esters, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, acryl amide or acrylic esters, or mixtures thereof, alkali polyphosphates, phosphonic-, citric- or tartaric acids, salts or esters thereof, or mixtures thereof.

42. The process according to claim 25, wherein before fibrillating in step (d), the pH of the combination of the cellulose fibres and the at least one filler and/or pigment is adjusted to a pH of 10 to 12.

43. The process according to claim 25, wherein after fibrillating in step (d), the pH of the suspension is re-adjusted to a pH of 7.5 to 9.5.

44. The process according to claim 25, wherein after fibrillating in step (d), the pH of the suspension is re-adjusted to a pH of about 8.5.

45. The process according to claim 25, wherein the combination resulting from step (c) is stored for 2 to 12 hours prior to fibrillating in step (d).

46. The process according to claim 25, wherein the combination resulting from step (c) is stored for 3 to 10 hours, prior to fibrillating in step (d).

47. The process according to claim 25, wherein the combination resulting from step (c) is stored for 4 to 8 hours, prior to fibrillating in step (d).

48. The process according to claim 25, wherein a cellulose solvent is added to the combination in step (c) prior to fibrillating in step (d).

49. The process according to claim 25, wherein the cellulose solvent is copper(II)ethylenediamine, iron-sodium-tartrate or lithium-chloride/dimethylacetamine.

50. The process according to claim 25, wherein in step (d) the weight ratio of fibres to the at least one filler and/or pigment on a dry weight basis is from 1:6 to 6:1.

51. The process according to claim 25, wherein in step (d) the weight ratio of fibres to the at least one filler and/or pigment on a dry weight basis is from 1:4 to 4:1.

52. The process according to claim 25, wherein in step (d) the weight ratio of fibres to the at least one filler and/or pigment on a dry weight basis is from 1:3 to 3:1.

53. The process according to claim 25, wherein in step (d) the weight ratio of fibres to the at least one filler and/or pigment on a dry weight basis is from 1:2 to 2:1.

54. A material composite, plastic, paint, rubber, concrete, ceramic, adhesive, food or wound-healing composition comprising the nano-fibrillar cellulose suspension according to claim 25.

55. The process according to claim 25, wherein the fibrillating in step (d) is carried out by an ultra-fine friction grinder or a homogenizer, and wherein the temperature of the suspension in the ultra-fine friction grinder or the homogenizer is above 60° C.

56. The process according to claim 25, wherein the fibrillating in step (d) is carried out by an ultra-fine friction grinder or a homogenizer, and wherein the temperature of the suspension in the ultra-fine friction grinder or the homogenizer is above 80° C.

57. The process according to claim 25, wherein the fibrillating in step (d) is carried out by an ultra-fine friction grinder or a homogenizer, and wherein the temperature of the suspension in the ultra-fine friction grinder or the homogenizer is above 90° C.

58. The process according to claim 25, wherein the combination from step (c) is fibrillated in step (d) until a Schopper Riegler degree is increased by ≥6° SR.

59. The process according to claim 25, wherein the combination from step (c) is fibrillated in step (d) until a Schopper Riegler degree is increased by ≥8° SR.

60. The process according to claim 25, wherein the combination from step (c) is fibrillated in step (d) until a Schopper Riegler degree is increased by ≥10° SR.

61. The process according to claim 25, wherein the combination from step (c) is fibrillated in step (d) until a Schopper Riegler degree is increased by ≥15° SR.

62. The process according to claim 25, wherein the combination of fibres to the at least one filler and/or pigment from step (c) is fibrillated in step (d) until a final Schopper-Riegler degree of ≥60° SR is reached.

63. The process according to claim 25, wherein the combination of fibres to the at least one filler and/or pigment from step (c) is fibrillated in step (d) until a final Schopper-Riegler degree of ≥70° SR is reached.

64. The process according to claim 25, wherein the combination of fibres to the at least one filler and/or pigment filler from step (c) is fibrillated in step (d) until a final Schopper-Riegler degree of ≥80° SR is reached.

Description

DESCRIPTION OF THE FIGURES

[0069] FIG. 1 shows the ° SR/passage for pulp suspensions fibrillated with and without different natural ground calcium carbonates.

[0070] FIG. 2 shows the ° SR/passage for pulp suspensions fibrillated with different fillers/pigments.

[0071] FIG. 3 shows the ° SR/running time for pulp suspensions ground in a ball mill with and without natural ground calcium carbonate.

[0072] FIG. 4 shows the ° SR/running time for pulp suspensions ground with and without natural ground calcium carbonate added before or after fibrillation.

EXAMPLES

[0073] 1. Increase of ° SR/Passage Using GCC

[0074] For examining the development of the ° SR/passage, eucalyptus pulp with a ° SR of 25 was treated first in an ultra-fine friction grinder at 4 wt-% solids content with and without the addition of GCC. A similar experiment was run on an homogenizer with eucalyptus pulp at 1.5 wt-% solids content with and without GCC.

[0075] Material [0076] GCC: Omyacarb 1-AV (solids content 100 wt % based on weight of fibres present) available from Omya AG. The weight median particle size d.sub.50=1.7 μm measured by Sedigraph 5100. [0077] Omyacarb 10-AV (solids content 100 wt-% based on weight of fibres present) available from Omya AG. The weight median particle size d.sub.50 is 10.0 μm measured by Sedigraph 5100. [0078] Pulp: Eucalyptus pulp with 25° SR and an equivalent aqueous suspension pH of 7.6.

Example 1—Ultrafine Friction Grinder

[0079] For the comparative example eucalyptus pulp in the form of dry mats of 500 g per mat (700×1 000×1.5 mm) was used. 170 g pulp thereof was torn into pieces of 40×40 mm. 3 830 g tap water was added. The suspension was stirred in a 10 dm.sup.3 bucket at 2000 rpm using a dissolver disk with a diameter of 70 mm. The suspension was stirred for at least 15 minutes at 2000 rpm.

[0080] The suspension was then fibrillated with an ultra-fine friction grinder (Supermasscolloider from Masuko Sangyo Co. Ltd, Japan (Model MKCA 6-2)). The grinding stones were silicon carbide with a grit class of 46 (grit size 297-420 μm). The gap between the grinding stones was chosen to be the dynamic 0-point as described in the manual delivered by the supplier. The speed of the rotating grinder was adjusted to be 1200 rpm. The suspension was recirculated several times and samples were taken. The Schopper-Riegler degree (° SR) was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1.

[0081] For the inventive example eucalyptus pulp in the form of dry mats of 500 g per mat (700×1 000×1.5 mm) was used. 170 g pulp thereof was torn into pieces of 40×40 mm. 160 g Omyacarb 1-AV was added. 3 830 g tap water was added. The suspension was stirred in a 10 dm.sup.3 bucket at 2000 rpm using a dissolver disk with a diameter of 70 mm. The suspension was stirred for at least 15 minutes at 2000 rpm. The suspension had a pH of about 7.5.

[0082] The suspension was then fibrillated with an ultra-fine friction grinder (Supermasscolloider from Masuko Sangyo Co. Ltd, Japan (Model MKCA 6-2)). The grinding stones were silicon carbide with a grit class of 46 (grit size 297-420 μm). The gap between the grinding stones was chosen to be the dynamic 0-point as described in the manual delivered by the supplier. The speed of the rutating grinder was adjusted to be 1200 rpm. The suspension was recirculated several times and samples were taken. The Schopper-Riegler degree (° SR) was measured according to the Zelicheming Merkblatt V/7/61 and standardized in ISO 5267/1. The additional filler was not considered for the requested 2 g/l pulp consistency for the measurement.

[0083] For the inventive example eucalyptus pulp in the form of dry mats of 500 g per mat (700×1 000×1.5 mm) was used. 170 g pulp thereof was torn into pieces of 40×40 mm. 160 g Omyacarb 10-AV was added. 3 830 g tap water was added. The suspension was stirred in a 10 dm.sup.3 bucket at 2 000 rpm using a dissolver disk with a diameter of 70 mm. The suspension was stirred for at least 15 minutes at 2 000 rpm. The suspension had a pH of about 7.2.

[0084] The suspension was then fibrillated with an ultra-fine friction grinder (Supermasscolloider from Masuko Sangyo Co. Ltd, Japan (Model MKCA 6-2)). The grinding stones were silicon carbide with a grit class of 46 (grit size 297-420 μm). The gap between the grinding stones was chosen to be the dynamic 0-point as described in the manual delivered by the supplier. The speed of the rotating grinder was adjusted to be 1200 rpm. The suspension was recirculated several times and samples were taken. The Schopper-Riegler degree (° SR) was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1. The additional filler was not considered for the requested 2 g/l pulp consistency for the measurement.

[0085] Results

[0086] FIG. 1 shows the development of the ° SR as a function of passages through the Supermasscolloider. It becomes apparent that the addition of GCC increases the efficiency of the device per passage.

Example 2—Homogenizer

[0087] For the comparative example eucalyptus pulp in the form of dry mats of 500 g per mat (700×1 000×1.5 mm) was used. 47 g pulp thereof was torn into pieces of 40×40 mm. 2953 g tap water was added. The suspension was stirred in a 5 dm.sup.3 bucket at 2000 rpm using a dissolver disk with a diameter of 70 mm. The suspension was stirred for at least 15 minutes at 2000 rpm.

[0088] This suspension was fed into the Homogenizer (GEA Niro Soavi NS2006L) but did not run through the machine.

[0089] For the inventive example eucalyptus pulp in the form of dry mats of 500 g per mat (700×1000×1.5 mm) was used. 47 g pulp thereof was torn into pieces of 40×40 mm. 45 g Omyacarb 1-AV was added. 2953 g tap water was added. The suspension was stirred in a 5 dm.sup.3 bucket at 2000 rpm using a dissolver disk with a diameter of 70 mm. The suspension was stirred for at least 15 minutes at 2000 rpm.

[0090] This suspension was fed into the Homogenizer (GEA Niro Soavi NS2006L). The flow through the homogenizer was between 100 and 200 g min.sup.−1 and the pressure was adjusted to be between 200 and 400 bar. The suspension was recirculated several times and samples were taken. The Schopper-Riegler degree (° SR) was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1. The additional filler was not considered for the requested 2 g/l pulp consistency for the measurement.

[0091] Results

[0092] The comparative sample that contained no GCC could not be fed through the homogenizer. Only the GCC containing sample showed a good runnability. Schopper-Riegler values are reported in Table I after 5 and 10 passages through the homogenizer.

TABLE-US-00001 TABLE 1 Passages ° SR 0 25 5 74 10 91

[0093] 2. Increase of ° SR Using PCC in a Refiner

Example 3—Ultrafine PCC

[0094] Material [0095] PCC: Ultrafine prismatic PCC. The weight median particle size d.sub.50=1.14 μm measured by Sedigraph 5100 (100 wt-% of particles have a diameter <2 μm; 27 wt-% of particles have a diameter <1 um). [0096] This PCC was provided in the form of an aqueous suspension having a solids content of 7.9 wt-%. [0097] Pulp: Longfibre bleached kraft pulp with 16° SR and an equivalent aqueous suspension pH of between 6 and 8.

[0098] An aqueous suspension was formed of the above carbonate and pulp such that this suspension had a solids content of approximately 4 wt-% and a carbonate:pulp weight ratio of 29:71.

[0099] Approximately 12.5 dm.sup.3 of this suspension were circulated during a period of 9 minutes through an Escher Wyss R 1 L Labor-Refiner under 5.4 kW.

[0100] A Schopper-Riegler (° SR) of the obtained suspension of 92° SR was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1.

Example 4—Coarse PCC

[0101] a) Suspension According to the Invention

[0102] Material [0103] PCC: Scalenohedral PCC. The weight median particle size d.sub.50=3.27 μm measured by Sedigraph 5100 (11 wt-% of particles have a diameter <2 μm; 4 wt-% of particles have a diameter <1 um). This PCC was provided in the form of an aqueous suspension having a solids content of 15.8%. [0104] Pulp: Eucalyptus with 38° SR and an equivalent aqueous suspension pH of between 6 and 8.

[0105] An aqueous suspension was formed of the above carbonate and pulp such that this suspension had a solids content of approximately 9.8 wt-% and a carbonate:pulp weight ratio of 75:25. This suspension presented an 18° SR.

[0106] Approximately 38 m.sup.3 of this suspension was circulated during a period of 17.5 hours through a Metso Refiner RF-0 under 92 kW at a flow rate of 63 m.sup.3/hour.

[0107] A Schopper-Riegler (° SR) of the obtained suspension of 73° SR was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1.

[0108] b) Comparative Suspension

[0109] Material [0110] PCC: Scalenohedral PCC. The weight median particle size d.sub.50=3.27 μm measured by Sedigraph 5100 (11 wt-% of particles have a diameter <2 μm; 4 wt-% of particles have a diameter <1 um). This PCC was provided in the form of an aqueous suspension having a solids content of 15.8%. [0111] Pulp: Eucalyptus with 38° SR and an equivalent aqueous suspension pH of between 6 and 8.

[0112] An aqueous suspension was formed of the above pulp such that this suspension had a solids content of approximately 4.5 wt-%.

[0113] Approximately 20 m.sup.3 of this suspension was circulated during a period of 17.5 hours through a Metso Refiner RF-0 under 92 kW at a flow rate of 63 m.sup.3/hour.

[0114] A Schopper-Riegler (° SR) of the obtained suspension of 65° SR was measured according to the Zelicheming Merkblatt V/7/61 and standardized in ISO 5267/1.

[0115] To this suspension, the above scalenohedral PCC was added in an amount so as to obtain a carbonate:pulp weight ratio of 75:25. A Schopper-Riegler (° SR) of the obtained suspension of 25° SR was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1.

[0116] This clearly shows that the presence of calcium carbonate during the fibrillation step is essential for obtaining a high Schopper Riegler degree, i.e. an efficient fibrillation of the cellulose fibres.

[0117] 3. Increase of ° SR/Passage Using Different Fillers or Pigments and/or Different Pulps

[0118] For examining the development of the ° SR/passage, eucalyptus or pine pulp was treated in an ultra-fine friction grinder with the addition of the filler or pigment as indicated here below.

[0119] Material [0120] GCC: Aqueous suspension of natural ground calcium carbonate dispersed with polymeric acrylic acid-based dispersant, solids content 50 wt-%). The volume median particle size d.sub.50 is 246 nm measured by Malvern Zetasizer Nano ZS. [0121] Talc: Finntalc F40 available from Mondo Minerals. [0122] Pulp: Eucalyptus pulp in the form of dry mats, with 17 to 20° SR, a brightness of 88.77% (ISO 2470-2) and an equivalent aqueous suspension pH of between 7 and 8. [0123] Pine pulp in the form of dry mats, with 17 to 20° SR, a brightness of 88.19% (ISO 2470-2) and an equivalent aqueous suspension pH of between 7 and 8.

Example 5—Ultrafine Friction Grinder

[0124] In the following examples, the pulp indicated in the Table below, in the form of dry mats, was used. 90 g pulp thereof was torn into pieces of 40×40 mm. The filler indicated in the Table below was added in the indicated amount, along with 2 190 g of tap water. The suspensions were each stirred in a 10 dm.sup.3 bucket at 2000 rpm using a dissolver disk with a diameter of 70 mm. The suspensions were each stirred for at least 10 minutes at 2000 rpm.

[0125] The suspensions were then fibrillated with an ultra-fine friction grinder (Supermasscolloider from Masuko Sangyo Co. Ltd, Japan (Model MKCA 6-2)). The grinding stones were silicon carbide with a grit class of 46 (grit size 297-420 μm). Prior to commencing the following tests, the gap between the grinding stones was set to be the dynamic 0-point as described in the manual delivered by the supplier. For each the tests below, the gap between the grinding stones were further closed from this 0-point by 5 increments, corresponding to an adjustment of −50 μm, as soon as the first material passed between the stones. The speed of the rotating grinder was adjusted to be 2000 rpm for the first 5 passages, and decreased to 1500 rpm for passage 6 and to 1000 rpm for passage 7. Following each passage, the rpm of the friction grinder was increased to approximately 2600 rpm for a period of 5 seconds in order to ensure that a maximum of materials was extracted from the friction grinder before commencing the following passage directly thereafter. The Schopper-Riegler degree (° SR) was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1. The additional filler was not considered for the requested 2 g/l pulp consistency for the measurement. So the pulp consistency was constant for Tests a and b at 2 g/l.

TABLE-US-00002 Test a) b) Type pulp: Eucalyptus Pine Type filler/pigment GCC Finntalc F40 Amount filler/pigment 90 g [180 g] 90 g (g dry, [g suspension]) Weight ratio 1:1 1:1 filler/pigment:fibre

[0126] Results

[0127] FIG. 2 shows the development of the ° SR as a function of passages through the Supermasscolloider. It becomes apparent that the addition of filler results in an efficient ° SR development in the device per passage (compared to tests g and f below), also for other pulp types than Eucalyptus and other filler types than GCC and PCC.

[0128] 4. Increase of ° SR/Passage of Comparative Example Treating Pulp in a Ball Mill with and without GC

[0129] For examining the development of the ° SR/passage, eucalyptus pulp was treated in a ball mill with and without the addition of the filler or pigment as indicated here below.

[0130] Material [0131] GCC: Omyacarb 1-AV in the form of a powder, available from Omya AG. The weight median particle size d.sub.50=1.7 μm measured by Sedigraph 5100. [0132] Pulp: Eucalyptus pulp in the form of dry mats, with 17 to 20° SR, a brightness of 88.77% (ISO 2470-2) and an equivalent aqueous suspension pH of between 7 and 8.

Example 6—Ball Mill

[0133] In the following examples, the pulp indicated in the table below, in the form of dry mats, was used. 88 g pulp thereof was torn into pieces of 40×40 mm. Omyacarb 1-AV was added in the amount indicated in the Table below, along with 5000 g of tap water. The suspensions were each stirred in a 10 dm.sup.3 bucket at 2000 rpm using a dissolver disk with a diameter of 70 mm. The suspensions were each stirred for at least 10 minutes at 2000 rpm.

[0134] 1600 g of each suspension was then introduced in a 3 dm.sup.3 porcelain vessel filled with 3500 g of Verac beads having a bead diameter of 2 cm. The vessel was closed and rotated 43 rpm for a period of 24 hours. The Schopper-Riegler degree (° SR) was measured according to the Zellcheming Merkblatt V/7/61 and standardized in ISO 5267/1. The additional filler was not considered for the requested 2 g/l pulp consistency for the measurement. So the pulp consistency was constant for Tests c and d at 2 g/l.

TABLE-US-00003 Test c) d) Type pulp Eucalyptus Eucalyptus Type filler/pigment None Omyacarb 1-AV Amount filler/pigment 0 g 28.2 g (g dry, [g suspension]) Weight ratio n/a 1:1 filler/pigment:fibre

[0135] Results

[0136] FIG. 3 shows the development of the ° SR as a function of passages through the ball mill. It is apparent that the addition of filler does not positively influence the ° SR development in the device over time.

[0137] 5. Beneficial Effect of Filler

Example 7—Ultrafine Friction Grinder

[0138] Tests e to g were processed with an ultra-fine friction grinder (Supermasscolloider from Masuko Sangyo Co. Ltd, Japan (Model MKCA 6-2) with mounted silicon carbide stones having a grit class of 46 (grit size 297-420 M). The gap between the stones was adjusted to “−50” μm (dynamic 0-point, as described in the manual delivered by the supplier). The speed of the rotating grinder was set to 2000 rpm for passes 1-5, to 1500 rpm for pass 6 and to 1000 rpm for pass 7. Samples for Shopper-Riegler degree measurements were taken before grinding, after passes 5, 6 and 7. The Shopper-Riegler degree (° SR) was measured according to the Zelicheming Merkblatt V/7/61 and standardized in ISO 5267/1. The additional filler was not considered for the requested 2 g/l pulp consistency for the measurement. So the pulp consistency was constant for all tests e to g at 2 g/I.

[0139] Material: [0140] Omyacarb 1 AV Omyacarb 1-AV available from OmyaAG; Fine calcium carbonate powder, manufactured from a high purity, white marble; The weight median particle size d.sub.50 is 1.7 μm measured by Sedigraph 5100. [0141] Eucalyptus pulp Dry mat, brightness: 88.77% (ISO 2470-2), equivalent pulp suspension pH between 7 and 8 and ° SR between 17 and 20

[0142] Test e):

[0143] 90 g dry Eucalyptus pulp, 2910 g tap water and 90 g Omyacarb 1 AV (1:1 pulp to filler, dry/dry) were mixed using a Pendraulik stirrer at 2000 rpm with a mounted dissolver disk (d=70 mm) for at least 10 minutes. This mixture was processed with the Supermasscolloider as described above in the according paragraph. Samples were taken and measured as described above in the according paragraph.

[0144] Test f) (Comparative Test):

[0145] 90 g dry Eucalyptus pulp and 2910 g tap water were mixed using a Pendraulik stirrer at 2000 rpm with a mounted dissolver disk (d=70 mm) for at least 10 minutes. This mixture was processed with the Supermasscolloider as described above in the according paragraph. Samples were taken and measured as described above in the according paragraph.

[0146] Test g) (Comparative Test):

[0147] Same as test f) but 90 g Omyacarb 1 AV added after fibrillation.

[0148] Results

[0149] FIG. 4 shows that the addition of filler (test g) to a nanocellulosic suspension that was produced in the absence of filler (test f) leads to increased ° SR values, but not to a change of steepness (that means no efficiency increase).

[0150] However a nanocellulosic suspension that was produced in the presence of filler (test e) shows a higher increase of ° SR compared to the comparative tests (g and f).

[0151] 6. Use of Nano-Fibrillar Cellulose Suspension in Paper Making

[0152] 60 g dry of a sulphated paste of wood and fibres composed of 80% birch and 20% pine, with a freeness value of 23° SR, is diluted in 10 dm.sup.3 of water. To this dilution is added approximately 1.5 g dry of the nano-fibrillar cellulose suspension produced according to Example 1 using Omyacarb 1-AV, as well as a 62 wt-% suspension of a pro-dispersed natural ground calcium carbonate (marble) having a microcrystalline, rhombohedral particle shape and a weight median particle size d.sub.50 of 0.8 μm (measured by Sedigraph 5100). The latter is added in an amount so as to obtain an overall filler content of 30+/−0.5% based on the final paper weight. After 15 minutes of agitation and following addition of 0.06% by dry weight, relative to the dry weight of the paper, of a polyacrylamide retention aid, a sheet with a grammage of 75 g/m.sup.2 is formed using Rapid-Köthen type hand sheet former.