METHOD FOR DISPERSING NANOPARTICLES IN FLUID MEDIA

1 . A process for dispersing nanoparticles in a medium-viscosity fluid medium, wherein the nanoparticles and the fluid medium together make a number m passages through one or more multiscrew extruders having one or more kneading zones, where m is an integer greater than or equal to 1.

2 . The process of claim 1 , wherein each single passage i has one or more kneading zones having a total length of LK i and an internal barrel diameter of D i and the parameter K 1

K





1

=

∑

i

=

1

m



LK

i

D

i

is greater than 10

3 . The process of claim 1 , wherein the nanoparticles and the fluid medium remain for a residence time of tk i in one or more kneading zones during the passage i and the parameter K 2

K





2

=

∑

i

=

1

m



n

i



tk

i

is greater than 500, where n i is the rotational speed of the multiscrew extruder present in the respective passage.

4 . The process of claim 1 , wherein at least part of the kneading zone(s) is formed by kneading elements whose cross-sectional profile can be represented by an always differentiatable profile curve.

5 . The process of claim 4 , wherein the nanoparticles and the fluid medium remain for a residence time of te i in one or more zones having kneading elements whose cross-sectional profile can be represented by an always differentiatable profile curve during the passage i and the parameter K 3

K





3

=

∑

i

=

1

m



n

i



te

i

is greater than 300, where n i is the rotational speed of the multiscrew extruder present in the respective passage.

6 . The process of claim 1 , wherein one or more of said multiscrew extruders have an arrangement of transport-active kneading elements, followed in the transport direction by transport-neutral or backwards-transporting kneading discs or a combination of transport-neutral and backwards-transporting kneading discs.

7 . The process of claim 1 , wherein the nanoparticles are metered dry into a feed hopper of a multiscrew extruder while the medium-viscosity fluid medium is introduced downstream thereof.

8 . The process of claim 1 , wherein a precondensate is produced in a first step and is diluted with further fluid medium in a second step.

9 . Process according to claim 8 , wherein the ratio of the precondensate to the further fluid medium is in the range from 1:1000 to 3:1.

10 . Process according to claim 8 , wherein the further fluid medium differs in at least one feature selected from the group consisting of viscosity, molecular weight, number of functional groups per molecule.

11 . Process according to claim 1 , wherein said nanoparticles are carbon nanotubes.

12 . Process according to claim 1 , wherein the fluid medium has a viscosity in the range from 0.5 to 1000 Pa·s at 15° C. to 30° C.

13 . Process according to claim 1 , wherein the fluid medium is one or more compounds selected from the group consisting of isocyanates, polyols, epoxy resins, polyester resins, phenol-formaldehyde resins, melamine resins, melamine-phenol resins, silicones and prepolymers.

14 . The process of claim 2 , wherein K 1 is greater than 20.

15 . The process of claim 14 , wherein K 1 is greater than 50.

16 . The process of claim 3 , wherein K 2 is greater than 2500.

17 . The process of claim 16 wherein K 2 is greater than 5000.

18 . The process of claim 5 , wherein K 3 is greater than 2000.

19 . The process of claim 18 , wherein K 3 is greater than 4000.