Conductive composite compositions with fillers

• US 20080118736A1
• Filed: 08/31/2007
• Published: 05/22/2008
• Est. Priority Date: 05/16/2006
• Status: Active Grant

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Liu, Wanjun, Fukushima, Hiroyuki, Drzal, Lawrence T., Do, InHwan
• Granted Patent: US 8,017,228 B2
• Time in Patent Office: Days
• US Class Current: 428/297.4
• CPC Class Codes: B05D 1/045 on non-conductive substrates
• CPC Class Codes: C03C 25/465 Coatings containing composite materials
• CPC Class Codes: C08J 5/06 using pretreated fibrous materials
• CPC Class Codes: D06M 11/74 with carbon or graphite; with carbides; with graphitic acids or their salts
• CPC Class Codes: D06M 2200/00 Functionality of the treatment composition and/or properties imparted to the textile material
• CPC Class Codes: D06M 23/08 Processes in which the treating agent is applied in powder or granular form adhesives for multi-layer textile fabrics D06M17/00
• CPC Class Codes: Y10T 428/24994 Fiber embedded in or on the surface of a polymeric matrix
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/292 In coating or impregnation
• CPC Class Codes: Y10T 428/2991 Coated

Abstract

Composite materials with a polymer matrix, low resistivity graphite coated fillers having exfoliated and pulverized graphite platelets coated on an outer surface of high resistivity fillers, are provided. The fillers can be fibers or particles. The composite materials incorporating the graphite coated fillers as reinforcements can be electrostatically painted without using a conductive primer on the polymer matrix.

Claims

1. A reinforced composite material which comprises:

(a) polymeric matrix in admixture with a plurality of graphite coated fibers mixed in the polymeric matrix, the fiber having a high resistivity and having an outer surface, and exfoliated and pulverized platelets of the graphite having a particle size between about 0.1 and 500 microns coated on the outer surface of the fiber; and

(b) high resistivity particles coated with the graphite platelets in the polymeric matrix, wherein the reinforced composite material enables electrostatic painting.

2. The reinforced composite material of claim 1, wherein the fibers comprise glass fibers.

3. The reinforced composite material of claim 2, wherein the weight fraction of the platelets on the outer surface of the glass fibers is from about 0.01 wt % to about 15 wt % of the weight of the fibers and on the outer surface of the particles is from about 0.05 to 20% of the weight of the particles.

4. The reinforced composite material of claim 1, wherein the fibers comprise polymer fibers.

5. The reinforced composite material of claim 1, wherein the polymeric matrix comprises a thermoset or thermoplastic organic polymer.

6. The composite material of any one of claims 1, 2, 3, 4 or 5 wherein the particles are calcium carbonate particles.

7. The composite material of any one of claims 1, 2, 3, 4 or 5 wherein the fibers are as a bundle of fibers.

8. The composite material of any one of claims 1, 2, 3, 4 or 5 wherein the fibers are as a bundle of fibers and the particles are calcium carbonate.

9. The composite material of any one of claims 1, 2, 3, 4 or 5 wherein the composite is as a sheet molding composition with the fibers which are chopped in the polymer matrix.

10. The composite material of any one of claims 1, 2, 3, 4 or 5 wherein the fibers are distributed throughout the polymer matrix.

11. A method of electrostatic painting a reinforced composite material without using a conductive primer comprising the steps of:

(a) providing a reinforced composite material which comprises a polymeric matrix in admixture with a plurality of graphite coated fibers mixed in the polymeric matrix comprising the fibers having a high resistivity and having an outer surface, and exfoliated and pulverized platelets of the graphite having a particle size between about 0.1 and 500 microns coated on the outer surface of the fiber; and

high resistivity particles coated with the graphite platelets;

(b) electrically grounding the reinforced composite material;

(c) providing a charged powder comprising a resin and a pigment;

(d) spraying the charged powder onto the electrically grounded reinforced composite material so as to coat the material; and

(e) curing the powder on the reinforced composite material in a curing oven, so as to electrostatically paint the reinforced composite material with the powder.

12. The method of claim 11, wherein the fibers are glass fibers.

13. The reinforced composite material of claim 12, wherein the weight fraction of the platelets on the outer surface of the glass fibers is from about 0.01 wt % to about 15 wt % of the weight of the fibers and on the outer surface of the particles is from about 0.05 to 20% of the weight of the particles.

14. The reinforced composite material of claim 11, wherein the fibers comprise polymer fibers.

15. The reinforced composite material of claim 11, wherein the polymeric matrix comprises a thermoset or thermoplastic organic polymer.

16. The composite material of any one of claims 11, 12, 13, 14 or 15 wherein the particles are calcium carbonate particles.

17. The composite material of any one of claims 11, 12, 13, 14 or 15 wherein the fibers are as a bundle of fibers.

18. The composite material of any one of claims 11, 12, 13, 14 or 15 wherein the fibers are as a bundle of fibers and the particles are calcium carbonate.

19. The composite material of any one of claims 11, 12, 13, 14 or 15 wherein the composite is as a sheet molding composition with the fibers which are chopped in the polymer matrix.

20. A method of making a plurality of low resistivity graphite coated fillers comprising the steps of:

(a) providing a plurality of high resistivity fillers;

(b) providing a graphite solution comprising exfoliated and pulverized graphite particles having a particle size between about 0.1 and 500 microns in the solution;

(c) coating the plurality of the fillers with the graphite solution; and

(d) drying the sprayed fillers to provide the low resistivity graphite coated fibers.

21. A method of making a plurality of low resistivity graphite coated fillers comprising the steps of:

(a) providing a plurality of high resistivity fillers;

(b) providing a graphite solution comprising exfoliated and pulverized graphite particles having a particle size between about 0.1 and 500 microns in a solution;

(c) spraying the graphite solution onto the plurality of fillers for a time to provide sprayed fillers; and

(d) drying the sprayed fillers to provide the low resistivity graphite coated fillers.

22. A method of making a plurality of low resistivity graphite coated fillers comprising the steps of:

(a) providing a plurality of high resistivity fillers;

(b) providing a graphite solution comprising exfoliated and pulverized graphite particles having a particle size between about 0.1 and 500 microns mixed in a solution;

(c) coating the plurality of fillers with the graphite solution; and

(d) drying the fillers to provide the low resistivity graphite coated fillers.

23. A method of electrostatic painting a reinforced composite material without using a conductive primer comprising the steps of:

(a) providing a reinforced composite material which comprises a polymeric matrix; and

a plurality of graphite coated fillers mixed in the polymeric matrix, each of the fillers comprising a high resistivity filler and having an outer surface, and exfoliated and pulverized graphite platelets having a particle size between about 0.1 and 500 microns coated on the outer surface of the filler to provide the coated filler;

(b) electrically grounding the reinforced composite material;

(c) providing a charged powder comprising a resin and a pigment;

(d) spraying the charged powder onto the electrically grounded reinforced composite material so as to coat the material; and

(e) curing the powder on the reinforced composite material in a curing oven, so as to electrostatically paint the reinforced composite material with the powder.

24. A reinforced composite material which comprises in admixture:

(a) polymeric matrix; and

(b) a plurality of graphite coated fillers mixed in the polymeric matrix, the filler having a high resistivity and having an outer surface, and exfoliated and pulverized platelets of the graphite having a particle size between about 0.1 and 500 microns coated on the outer surface of the filler, wherein the reinforced composite material enables electrostatic painting.

25. The reinforced composite material of claim 24, wherein the filler comprises glass fibers.

26. The reinforced composite material of claim 25, wherein the weight fraction of the platelets on the outer surface of the glass fibers is from about 0.01 wt % to about 15 wt % of the weight of the fibers.

27. The reinforced composite material of claim 24, wherein the filler comprises polymer fibers.

28. The reinforced composite material of claim 24, wherein the polymeric matrix comprises a thermoset or thermoplastic organic polymer.

29. The composite material of any one of claims 24, 25, 26, 27 or 28 wherein the filler is particles.

30. The composite material of any one of claims 24, 25, 26, 27 or 28 wherein the filler is fibers as a bundle of fibers.

31. The composite material of any one of claims 24, 25, 26, 27 or 28 wherein the filler is fibers as a bundle of fibers and particles.

32. The composite material of any one of claims 24, 25, 26, 27 or 28 wherein the composite is as a sheet molding composition wherein the filler is fibers which are in chopped form in the polymer matrix.

33. The composite material of any one of claims 24, 25, 26, 27 or 28 wherein the fibers are distributed throughout the polymer matrix.