Morphological forms of fillers for electrical insulation

• US 20070026221A1
• Filed: 09/28/2006
• Published: 02/01/2007
• Est. Priority Date: 06/14/2005
• Status: Abandoned Application

• Current Assignee: Siemens Energy Incorporated (Siemens AG)
• Original Assignee: Siemens Power Generation, Inc.
• Inventors: Smith, James, Stevens, Gary, Wood, John
• Application Number:
  US11/529,181
• Publication Number:
  US 20070026221A1
• Time in Patent Office: Days
• US Class Current: 428/325
• CPC Class Codes: C09K 5/14 Solid materials, e.g. powdery or granular
• CPC Class Codes: H01F 27/2871 Pancake coils
• CPC Class Codes: H01F 41/127 Encapsulating or impregnating encapsulating coil and core H01F41/005
• CPC Class Codes: H01L 21/02107 Forming insulating materials on a substrate
• CPC Class Codes: H01L 21/316 composed of oxides or glassy oxides or oxide based glass
• CPC Class Codes: H02K 3/40 for high voltage, e.g. affording protection against corona discharges
• CPC Class Codes: H02K 9/227 Heat sinks
• CPC Class Codes: H05K 1/0373 containing additives, e.g. fillers H05K1/036 takes precedence
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles
• CPC Class Codes: H05K 2201/0248 Needles or elongated particles; Elongated cluster of chemically bonded particles microfibers H05K2201/0251; stacked conductors H05K2201/0379
• CPC Class Codes: Y10T 428/249959 Void-containing component is wood or paper
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/2916 including boron or compound thereof [not as steel]

Abstract

A high thermal conductivity resin that has a host resin matrix, and a high thermal conductivity filler. The high thermal conductivity filler (30) forms a continuous organic-inorganic composite with the host resin matrix. The fillers are from 1-1000 nm in length, and have average aspect ratios of between 3-100. At least a portion of the high thermal conductivity fillers comprise morphologies (31) chosen from one or more of hexagonal, cubic, orthorhombic, rhombohedral, tetragonal, whiskers and tubes. In particular, some of the fillers will aggregate into secondary structures.

Claims

1. A high thermal conductivity resin comprising:

a host resin matrix; and

a high thermal conductivity filler;

wherein said high thermal conductivity filler forms a continuous organic-inorganic composite with said host resin matrix;

wherein said high thermal conductivity fillers are from 1-1000 nm in length, and wherein said high thermal conductivity fillers have an average aspect ratio of between 3-100;

wherein at least a portion of said high thermal conductivity fillers comprise morphologies chosen from the group consisting of hexagonal, cubic, orthorhombic, rhombohedral, tetragonal, whiskers and tubes.

2. The high thermal conductivity resin of claim 1, wherein a portion of said high thermal conductivity fillers aggregate into secondary structures, whereby said aggregates are held together by chemical or physical bonding.

3. The high thermal conductivity resin of claim 2, wherein interconnection between secondary structures create thermal conduction through said host resin matrix.

4. The high thermal conductivity resin of claim 2, wherein said aggregate secondary structures form at least one of stacks, spheroids, splayed spheres, sheets, dendritic starts and pearl necklaces.

5. The high thermal conductivity resin of claim 2, wherein up to 50-100% by weight of said high thermal conductivity fillers form secondary structures.

6. The high thermal conductivity resin of claim 2, wherein 5-50% of said high thermal conductivity fillers do not form secondary structures.

7. The high thermal conductivity resin of claim 2, wherein the high thermal conductivity fillers that do not form secondary structures are of a different type of filler than high thermal conductivity fillers that form secondary structures.

8. The high thermal conductivity resin of claim 1, wherein said high thermal conductivity fillers comprise fillers that are decorated with nano fillers.

9. The high thermal conductivity resin of claim 8, wherein the nano fillers comprise 5-10% by weight of the total nano-decorated filler.

10. The high thermal conductivity resin of claim 8, wherein multiple secondary structures are formed within the same host resin matrix.

11. The high thermal conductivity resin of claim 1, wherein said high thermal conductivity fillers comprises hexagonal BN.

12. The high thermal conductivity resin of claim 11, wherein said hexagonal BN is approximately 50-200 nm in length.

13. The high thermal conductivity resin of claim 11, wherein said hexagonal boron nitride fillers aggregate into stacks.

14. The high thermal conductivity resin of claim 11, wherein smaller hexagonal BN fillers decorate larger hexagonal BN fillers.

15. The high thermal conductivity resin of claim 11, wherein the high thermal conductivity filler further comprise rod shaped fillers.

16. The high thermal conductivity resin of claim 1, wherein said high thermal conductivity fillers have an average aspect ratio of between 10-50.

17. The high thermal conductivity resin of claim 1, wherein reactive surface groups are present on said thermal conductivity filler.

18. A continuous organic-inorganic resin comprising:

a host resin network;

a first class of inorganic high thermal conductivity fillers evenly dispersed in said host resin network and essentially completely co-reacted with said host resin network; and

a second class of inorganic high thermal conductivity fillers unevenly dispersed in said host resin network, wherein said second class of inorganic high thermal conductivity fillers aggregate into secondary structures;

wherein said high thermal conductivity fillers have a length of between 1-1000 nm and an average aspect ratio of 3-100;

wherein said high thermal conductivity fillers are selected from at least one of oxides, nitrides, and carbides;

wherein at least a portion of said high thermal conductivity fillers comprise morphologies chosen from the group consisting of hexagonal, cubic, orthorhombic, rhombohedral, tetragonal, whiskers and tubes.

19. The continuous organic-inorganic resin of claim 18, wherein said second class of fillers self aggregate.

20. The continuous organic-inorganic resin of claim 18, wherein said second class of fillers are at least in part aggregated by an external mechanism.

21. The continuous organic-inorganic resin of claim 18, wherein said host resin network is impregnated into a mica paper.

22. The continuous organic-inorganic resin of claim 21, wherein said second class of fillers aggregate with greater concentration within voids in said mica paper.

23. The continuous organic-inorganic resin of claim 18, wherein said high thermal conductivity fillers have been surface treated to introduce surface functional groups that allows for the essentially complete co-reactivity with said host resin network.

24. The continuous organic-inorganic resin of claim 18, wherein said continuous organic-inorganic resin comprises a maximum of 60% by volume of said high thermal conductivity fillers.

25. The continuous organic-inorganic resin of claim 18, wherein said first class of filler is boron nitride and wherein said second class of filler is alumina

26. The continuous organic-inorganic resin of claim 25, wherein the boron nitride comprises 15-30% by weight of said continuous organic-inorganic resin, and wherein said alumina comprises 1-10% by weight of said continuous organic-inorganic resin.

27. The continuous organic-inorganic resin of claim 18, wherein the ratio of said second class of fillers to said first class of fillers is between 3:

1 to 10;

1 by weight.