In mold electronic printed circuit board encapsulation and assembly
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.
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.