Polyamide composition containing electrically conductive carbon

Patent metadata

Field	Value
Publication number	US-9312043-B2
Application number	US-201313804328-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 16, 2012
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A polyamide composition which provides moldings having a significantly reduced percolation threshold and an improved electrical conductivity is provided. The composition contains a) at least 40 parts by weight of a polyamide; b) from 0.15 to 25 parts by weight of an electrically conductive carbon; c) from 0.3 to 8 parts by weight of an oligofunctional compound; and, optionally, d) conventional auxiliaries and additives, wherein the electrically conductive carbon comprises at least one of carbon nanotubes and graphene, the oligofunctional compound comprises at least one functional group reactive with reactive groups on a surface of the electrically conductive carbon and at least one functional group reactive with an end group of the polyamide, and the sum of the parts by weight of the components a) to d) is 100.

First claim

The invention claimed is:

1. A polyamide composition, comprising:
a) at least 40 parts by weight of a polyamide;
b) from 0.15 to 25 parts by weight of an electrically conductive carbon;
c) from 0.3 to 8 parts by weight of an oligofunctional compound; and, optionally,
d) conventional auxiliaries and additives,
wherein
the electrically conductive carbon comprises at least one of carbon nanotubes and graphene,
the oligofunctional compound comprises at least one functional group reactive with reactive groups on a surface of the electrically conductive carbon and at least one functional group reactive with an end group of the polyamide, wherein the at least one functional group reactive with reactive groups on a surface of the electrically conductive carbon and the at least one functional group reactive with an end group of the polyamide of the oligofunctional compound are selected from the group of reactive functional groups consisting of an oxazinone group, an oxazolone group, an oxazoline group, an isocyanate group, a carbodiimide group, a N-acyllactam group, a N-acylimide group, an aromatic or aliphatic carbonic ester group, and an epoxide group,
with the proviso that
compounds which have at least two carbonic ester groups and no further different reactive groups and compounds which contain at least two carbodiimide groups are combined only with amino-functionalized carbon nanotubes, and that
compounds which have at least one epoxide group have a number average molecular weight M n of not more than 8000 g/mol; and
the sum of the parts by weight of the components a) to d) is 100.

2. The polyamide composition according to claim 1 , wherein the oligofunctional compound c) comprises from 2 to 40 functional groups.

3. The polyamide composition according to claim 1 , wherein a content of the electrically conductive carbon is from 3 to 25 parts by weight.

4. The polyamide composition according to claim 1 , which comprises covalent linkages wherein the oligofunctional compound bonds to the polyamide and to the carbon nanotubes or graphene.

5. The polyamide composition according to claim 1 , wherein the oligofunctional compound is of formula (IV):

6. The polyamide composition according to claim 1 , wherein the oligofunctional compound is of formula (I):

7. The polyamide composition according to claim 1 , wherein the oligofunctional compound is of formula (XI):

8. The polyamide composition according to claim 1 , wherein the polyamide comprises monomer units of an average of at least 8 carbon atoms.

9. The polyamide composition according to claim 8 , wherein the polyamide comprises at least one selected from the group consisting of PA610, PA88, PA8, PA612, PA810, PA106, PA108, PA9, PA613, PA614, PA618, PA812, PAl28, PA1010, PA1013, PA10, PA814, PA148, PA1012, PA11, PA1014, PA1212, and PA12.

10. The polyamide composition according to claim 1 , wherein the electrically conductive carbon comprises carbon nanotubes and the carbon nanotubes are multiwalled carbon nanotubes (MWCNTs).

11. The polyamide composition according to claim 10 , wherein the multiwalled carbon nanotubes (MWCNTs) are amino-functionalized.

12. A process for producing the polyamide composition according to claim 1 , comprising:
reacting the oligofunctional compound c) with the electrically conductive carbon in the absence of the polyamide; and
mixing the reaction product with the polyamide;
wherein optional constituents may be added to the mixture during the mixing.

13. A process for producing the polyamide composition according to claim 1 , comprising:
mixing the polyamide a), electrically conductive carbon b), oligofunctional compound c) and optionally conventional auxiliaries and additives d) together in a melt.

14. A process for producing the polyamide composition according to claim 1 , comprising:
producing a masterbatch of polyamide a), electrically conductive carbon b) and the oligofunctional compound c); and
mixing the masterbatch into a polyamide comprising end groups reactive with the oligofunctional compound c);
wherein the polyamide comprising end groups reactive with the oligofunctional compound c) optionally comprises conventional auxiliaries and additives.

15. The process according to claim 14 , wherein a content of electrically conductive carbon in the masterbatch is from 3 to 25 parts by weight.

16. An object obtained by a process comprising molding the polyamide composition according to claim 1 .

17. The object according to claim 16 , wherein the object is a fuel filter, a fuel line or a plug connector.

18. An instrument switch comprising a molding of the polyamide composition according to claim 1 , wherein the instrument switch is located in a location selected from the group consisting of an explosion-protected room and an antistatic house.

Assignees

• Haeger Harald
• Wursche Roland
• Hermasch Sylvia Anita
• Jakisch Lothar
• Krause Beate
• Poetschke Petra
• Socher Robert
• Evonik Degussa Gmbh

Inventors

• Haeger Harald
• Wursche Roland
• Hermasch Sylvia Anita
• Jakisch Lothar
• Krause Beate
• Poetschke Petra
• Socher Robert

Classifications

• H01B1/24

  the conductive material comprising carbon-silicon compounds, carbon or silicon · CPC title

• C08L77/06

  Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence) · CPC title

• C08J2477/00

  Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers · CPC title

• C08L77/00 Primary

  Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain (of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08); Compositions of derivatives of such polymers · CPC title

• C08K9/04

  Ingredients treated with organic substances {(treated with macromolecular compounds C08K9/08)} · CPC title