A method and a device for producing nanofibrillar cellulose

Patent metadata

Field	Value
Publication number	US-2016102433-A1
Application number	US-201414890392-A
Country	US
Kind code	A1
Filing date	May 13, 2014
Priority date	May 14, 2013
Publication date	Apr 14, 2016
Grant date	—

Abstract

In a method for producing nanofibrillar cellulose, cellulose based fiber material in dispersion is processed for separating fibrils. The method includes a first step where the fiber material is supplied to a disperser, where it flows through several counter-rotating rotors in such a way that the material is repeatedly subjected to shear and impact forces by the effect of the different counter-rotating rotors, and a second step, where the fiber material obtained from the first step is supplied to a homogenizer, where it is subjected to homogenization by the effect of pressure.

First claim

1 - 18 . (canceled)

19 . A method for producing nanofibrillar cellulose, wherein cellulose based fiber material in dispersion is processed for separating fibrils, the method comprising: a first step where the fiber material is supplied to a disperser, where it flows through several counter-rotating rotors in such a way that the fiber material is repeatedly subjected to shear and impact forces by the effect of different counter-rotating rotors, and a second step, where the fiber material obtained from the first step is supplied to a homogenizer, where it is subjected to homogenization by the effect of pressure.

20 . The method according to claim 19 , wherein in the first step, the fiber material is supplied through the several counter-rotating rotors outwards in radial direction with respect to a rotation axis of the rotors in such a way that the fiber material is repeatedly subjected to shear and impact forces by the effect of blades of the different counter-rotating rotors, whereby the fiber material is simultaneously fibrillated at least partly, wherein the fibrillation is effected by means of impact energy utilizing a series of frequently repeated impacts having varying directions of action.

21 . The method according to claim 19 , wherein in the second step, the homogenization pressure is 200 to 1000 bar.

22 . The method according to claim 19 , wherein in the first step, the passage of material through the disperser is repeated one or more times and/or in the second step, the passage of material through the homogenizer is repeated one or more times.

23 . The method according to claim 19 , wherein in the first step, the material is passed through the disperser 1-3 times, and in the second step, the material is passed through the homogenizer 1-3 times.

24 . The method according to claim 19 , wherein the nanofibrillar cellulose is produced continuously by passing the material continuously through a disperser or dispersers connected in series and by passing the material continuously through a homogenizer or homogenizers connected in series.

25 . The method according to claim 19 , wherein the fiber material is processed in the second step in the same consistency as obtained from the first step.

26 . The method according to claim 19 , wherein the fiber material is treated at least in the first step at a consistency of 1-8 wt-%.

27 . The method according to claim 26 , wherein the fiber material is treated in the second step at a consistency of 1.5-6 wt-%.

28 . The method according to claim 19 , wherein in the fiber material supplied to the first step, the internal bonds of the fiber have been weakened by chemical or enzymatic pretreatment.

29 . The method according to claim 28 , wherein the cellulose is anionically or cationically modified cellulose.

30 . The method according to claim 28 , wherein the cellulose is oxidized cellulose containing carboxyl groups.

31 . The method according to claim 28 , wherein the cellulose is carboxymethylated cellulose.

32 . The method according to claim 19 , wherein the nanofibrillar cellulose obtained from the second step has a Brookfield viscosity of at least 5,000 mPa·s, measured at a consistency of 0.8% and at 10 rpm.

33 . The method according to claim 19 , wherein the nanofibrillar cellulose obtained from the second step has turbidity value lower than 90 NTU, measured at a consistency of 0.1%.

34 . The method according to claim 19 , wherein the nanofibrillar cellulose obtained from the second step has a zero shear viscosity in the range of 1,000 to 100,000 Pa·s, and a yield stress in the range of 1 to 50 Pa, determined by rotational reometer at a consistency of 0.5 wt %.

35 . The method according to claim 19 , wherein in the second step, the homogenization pressure is 300 to 650 bar.

36 . The method according to claim 19 , wherein in the second step, the homogenization pressure is 310 to 450 bar.

37 . The method according to claim 19 , wherein the fiber material is treated at least in the first step at a consistency of 2-5 wt-%.

38 . The method according to claim 37 , wherein the fiber material is treated in the second step at a consistency of 2.5-4 wt-%.

39 . The method according to claim 19 , wherein the nanofibrillar cellulose obtained from the second step has a Brookfield viscosity of at least 15,000 mPa·s, measured at a consistency of 0.8% and at 10 rpm.

40 . The method according to claim 19 , wherein the nanofibrillar cellulose obtained from the second step has turbidity value of 5 to 90 NTU, measured at a consistency of 0.1%.

41 . The method according to claim 19 , wherein the nanofibrillar cellulose obtained from the second step has a zero shear viscosity in the range of 5,000 to 50,000, and a yield stress in the range of 3 to 15 Pa, determined by rotational reometer at a consistency of 0.5 wt %.

42 . A device for producing nanofibrillated cellulose from cellulose-based fiber material, comprising
a disperser comprising an inlet and outlet for fiber material and between the inlet and outlet, several counter-rotating rotors configured to subject fiber material dispersion repeatedly to shear and impact forces by the effect of different counter-rotating rotors, a homogenizer comprising an inlet and outlet for fiber material and between the inlet and outlet, a narrow through-flow gap, said homogenizer further comprising means configured to create pressure in fiber material dispersion before said through-flow gap to cause shearing and impact forces on the fiber material dispersion flowing through said through-flow gap, the outlet of the disperser being connected to the inlet of the homogenizer.

43 . The device according to claim 42 , wherein it comprises two dispersers connected in series and the outlet of the last disperser is connected to the inlet of a homogenizer or to the inlets of homogenizers connected in parallel.

Assignees

• Upm Kymmene Corp

Inventors

• Nuopponen Markus
• Tamper Juha
• Tienvieri Taisto

Classifications

• D21D1/006

  Disc mills · CPC title

• D21D1/20 Primary

  Methods of refining · CPC title

• D21C9/007 Primary

  by mechanical or physical means · CPC title

• D21H17/25

  Cellulose · CPC title

• D21D1/004

  Methods of beating or refining including disperging or deflaking · CPC title