In mold electronic printed circuit board encapsulation and assembly

• US 10,156,352 B2
• Filed: 04/16/2014
• Issued: 12/18/2018
• Est. Priority Date: 04/19/2013
• Status: Active Grant

• Current Assignee: Covestro LLC (Covestro AG), Thermal Solution Resources, LLC
• Original Assignee: Covestro LLC (Covestro AG), Thermal Solution Resources, LLC
• Inventors: Davis, Terry G., Rocco, David, Sagal, Mikhail, McCanna, Jessee, Sunderland, Nicolas, Lorenzo, James, Matsco, Mark, Dunay, Kevin
• Primary Examiner(s): Santiago, Mariceli
• Application Number:
  US14/784,975
• Publication Number:
  US 20160084490A1
• Time in Patent Office: 1,707 Days
• CPC Class Codes: B29C 67/246 Moulding high reactive monomers or prepolymers, e.g. by reaction injection moulding [RIM], liquid injection moulding [LIM] casting monomers B29C39/006, mixing construction B29B7/74
• CPC Class Codes: B29K 2075/00 Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2669/00 Use of PC, i.e. polycarbonates or derivatives thereof for preformed parts, e.g. for inserts
• CPC Class Codes: B29K 2995/0013 Conductive
• CPC Class Codes: B29L 2031/3425 Printed circuits
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 23/006 the substrate being distinct from the light source holder
• CPC Class Codes: F21V 29/773 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/87 Organic material, e.g. filled polymer composites; Thermo-conductive additives or coatings therefor
• CPC Class Codes: F21V 31/04 Provision of filling media
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

The present invention provides an assembly comprising a thermally conductive thermoplastic polymer as a heat sink to provide thermal management for an electrical/electronic component and a reaction injection molded (RIM) polyurethane to replace the potting compound typically used in such assemblies. In addition to replacing the potting compound, the cured polyurethane forms the part, such as the base of the LED bulb, which heretofore has been a separate component, thus reducing the number of components and saving a production step.

Claims

1. An assembly comprising:

a heat sink comprising a thermally conductive thermoplastic polymer composition;

a first electrical/electronic component;

a second electrical/electronic component; and

a polyurethane,

wherein the heat sink partially or fully surrounds the first electrical/electronic component, and

wherein the polyurethane partially or fully surrounds the second electrical/electronic components to form the assembly,

wherein the thermally conductive thermoplastic polymer composition comprises a blend selected from the group consisting of polycarbonate and polyethylene terephthalate, polycarbonate and polybutylene terephthalate, polycarbonate and polyphenylene sulfide, and polycarbonate and liquid crystalline polymers.

2. The assembly according to claim 1, wherein the first and second electrical/electronic components are each selected from the group consisting of a printed circuit board, a light emitting diode (LED), a resistor, a constant current driver, a driver/controller, a capacitor, a microprocessor, an integrated circuit, a photocell, a piezo-transducer, an inductor, and a proximity switch.

3. An assembly according to claim 1, wherein the first electrical/electronic component comprises an LED printed circuit board and the second electrical/electronic component comprises a driver/controller circuit board.

4. The assembly according to claim 1 further comprising at least one of a power supply and a threaded connector.

5. An assembly comprising:

a heat sink comprising a thermally conductive thermoplastic polymer composition;

a first electrical/electronic component;

a second electrical/electronic component; and

a polyurethane,

wherein the heat sink partially or fully surrounds the first electrical/electronic component, and

wherein the polyurethane partially or fully surrounds the second electrical/electronic components to form the assembly,

wherein the thermally conductive thermoplastic polymer composition comprises expanded graphite in an amount of from 10 wt.-% to 70 wt.-% of the composition.

6. The assembly according to claim 5, wherein the thermally conductive thermoplastic polymer composition contains an amorphous thermoplastic polymer selected from the group consisting of polypropylene, cyclic olefin copolymers, polycarbonate, polymethylmethacrylate and polystyrene.

7. The assembly according to claim 6, wherein the thermally conductive thermoplastic polymer composition comprises polycarbonate.

8. The assembly according to claim 5, wherein the thermally conductive thermoplastic polymer composition comprises expanded graphite in an amount of from 20 wt.-% to 60 wt.-% of the composition.

9. The assembly according to claim 8, wherein the thermally conductive thermoplastic polymer composition comprises expanded graphite in an amount of from 30 wt.-% to 50 wt.-% of the composition.

10. The assembly according to claim 5, wherein at least 90% of the particles of the expanded graphite have a particle size of at least 200 microns.

11. The assembly according to claim 5, wherein the first and second electrical/electronic components are each selected from the group consisting of a printed circuit board, a light emitting diode (LED), a resistor, a constant current driver, a driver/controller, a capacitor, a microprocessor, an integrated circuit, a photocell, a piezo-transducer, an inductor, and a proximity switch.

12. An assembly according to claim 5, wherein the first electrical/electronic component comprises an LED printed circuit board and the second electrical/electronic component comprises a driver/controller circuit board.

13. The assembly according to claim 5 further comprising at least one of a power supply and a threaded connector.

14. A process of making an assembly comprising:

partially or fully surrounding a first electrical/electronic component with a heat sink comprising a thermally conductive thermoplastic polymer;

partially or fully surrounding a second electrical/electronic component with a reaction injection molded polyurethane; and

forming the assembly by interlocking the reaction injection molded polyurethane with the heat sink,

wherein the thermally conductive thermoplastic polymer composition comprises a blend selected from the group consisting of polycarbonate and polyethylene terephthalate, polycarbonate and polybutylene terephthalate, polycarbonate and polyphenylene sulfide, and polycarbonate and liquid crystalline polymers.

15. The process according to claim 14, wherein the first and second electrical/electronic components are each selected from the group consisting of a printed circuit board, a light emitting diode (LED), a resistor, a constant current driver, a driver/controller, a capacitor, a microprocessor, an integrated circuit, a photocell, a piezo-transducer, an inductor, and a proximity switch.

16. The process according to claim 14, further comprising a step of inserting a power supply into a polyurethane reaction injection mold before reaction injection molding the polyurethane.

17. A process of making an assembly comprising:

partially or fully surrounding a first electrical/electronic component with a heat sink comprising a thermally conductive thermoplastic polymer;

partially or fully surrounding a second electrical/electronic component with a reaction injection molded polyurethane; and

forming the assembly by interlocking the reaction injection molded polyurethane with the heat sink,

wherein the thermally conductive thermoplastic polymer composition comprises expanded graphite in an amount of from 10 wt.-% to 70 wt.-% of the composition.

18. The process according to claim 17, wherein the thermally conductive thermoplastic polymer composition contains an amorphous thermoplastic polymer selected from the group consisting of polypropylene, cyclic olefin copolymers, polycarbonate, polymethylmethacrylate and polystyrene.

19. The process according to claim 18, wherein the thermally conductive thermoplastic polymer composition comprises polycarbonate.

20. The process according to claim 17, wherein the thermally conductive thermoplastic polymer composition comprises expanded graphite in an amount of from 20 wt.-% to 60 wt.-% of the composition.

21. The process according to claim 20, wherein the thermally conductive thermoplastic polymer composition comprises expanded graphite in an amount of from 30 wt.-% to 50 wt.-% of the composition.

22. The process according to claim 17, wherein at least 90% of the particles of the expanded graphite have a particle size of at least 200 microns.

23. The process according to claim 17, wherein the first and second electrical/electronic components are each selected from the group consisting of a printed circuit board, a light emitting diode (LED), a resistor, a constant current driver, a driver/controller, a capacitor, a microprocessor, an integrated circuit, a photocell, a piezo-transducer, an inductor, and a proximity switch.

24. The process according to claim 17, further comprising a step of inserting a power supply into a polyurethane reaction injection mold before reaction injection molding the polyurethane.

25. A process of making an assembly comprising:

partially or fully surrounding an LED printed circuit board with a heat sink comprising a thermally conductive thermoplastic polymer;

partially or fully surrounding a driver/controller circuit board with a reaction injection molded polyurethane; and

forming the assembly by interlocking the reaction injection molded polyurethane with the heat sink.

26. The process according to claim 25, wherein the thermally conductive thermoplastic polymer composition contains an amorphous thermoplastic polymer selected from the group consisting of polypropylene, cyclic olefin copolymers, polycarbonate, polymethylmethacrylate and polystyrene.

27. The process according to claim 26, wherein the thermally conductive thermoplastic polymer composition comprises polycarbonate.