Fusible phase-change powders for thermal management, methods of manufacture thereof, and articles containing the powders
A fusible, phase-change powder composition includes a plurality of powder particles comprising a polymer composition, an unencapsulated phase-change material, and optionally, an additive composition; wherein the powder composition is fusible at a temperature of 25 to 105° C., or 28 to 60° C., or 45 to 85° C., or 60 to 80° C., or 80 to 100° C.
1. A fusible, phase-change powder composition, comprising:
a plurality of powder particles comprising
5 to 20 weight percent of a polymer composition comprising a styrene-ethylene/propylene-styrene block copolymer, a styrene-butadiene block copolymer, or a styrene-ethylene/butylene-styrene block copolymer,
80 to 97 weight percent of an unencapsulated phase-change material comprising a paraffin having a melting temperature of 35 to 60° C., wherein weight percent is based on the total weight of the phase-change powder composition, and
optionally, an additive composition;
wherein the powder composition is fusible at a temperature of 25 to 105° C.
2. The fusible, phase-change powder composition of claim 1 , wherein the plurality of powder particles comprises 85 to 97 weight percent of the unencapsulated phase-change material comprising the paraffin having the melting temperature of 35 to 60° C., wherein weight percent is based on the total weight of the phase-change powder composition.
3. The fusible, phase-change powder composition of claim 1 , wherein
a solubility parameter of the polymer is within ±1 of the solubility parameter of the phase-change material.
4. The fusible, phase-change powder composition of claim 1 , wherein the plurality of powder particles comprises 90 to 97 weight percent of the unencapsulated phase-change material comprising the paraffin having the melting temperature of 35 to 60° C., wherein weight percent is based on the total weight of the phase-change powder composition.
5. The fusible, phase-change powder composition of claim 1 , wherein
the unencapsulated phase-change material has a heat of fusion, determined by differential scanning calorimetry according to ASTM D4118, of greater than 150 Joules/gram.
6. The fusible, phase-change powder composition of claim 1 , comprising the additive composition,
wherein the additive composition comprises an encapsulated phase-change material, a flame retardant, a thermal stabilizer, an antioxidant, a thermoconductive filler, a thermally insulating filler, a magnetic filler, a colorant, or a combination thereof.
7. The fusible, phase-change powder composition of claim 1 , comprising
5 to 20 weight percent of the additive composition;
wherein weight percent is based on the total weight of the phase-change powder composition and totals 100 weight percent.
8. The fusible, phase-change powder composition of claim 1 , having a heat of fusion, determined by differential scanning calorimetry according to ASTM D4118, at the melting temperature of
at least 150 Joules/gram.
9. The fusible, phase-change powder composition of claim 1 , wherein the average particle size of the powder is 1 to 500 micrometers.
10. A solid phase-change composition made from the fusible, phase-change powder of claim 1 .
11. A method of manufacturing the fusible, phase-change powder composition of claim 1 , the method comprising:
combining
a composition comprising the polymer composition and optionally a solvent,
molten unencapsulated phase-change material, and
optionally an additive composition to form a mixture;
optionally removing the solvent from the mixture;
cooling the mixture to provide a solid phase-change material; and
reducing the solid phase-change material to a powder to provide a fusible, phase-change powder composition.
12. The method of claim 11 , wherein reducing the solid phase-change material to a powder comprises grinding.
13. The method of claim 11 , wherein grinding is performed by a planetary ball mill.
14. The method of claim 11 , wherein the particle size of the powder is 1 to 500 micrometers.
15. An article comprising the fusible, phase-change powder composition of claim 1 .
16. The article of claim 15 , wherein the fusible, phase-change powder composition is disposed in a cavity of the article.
17. The article of claim 15 , wherein the fusible, phase-change powder composition is fused at elevated temperature to provide a solid.
18. A method of manufacturing an article comprising a phase-change composition, the method comprising
injecting the fusible, phase-change powder composition of claim 1 into a cavity of an article at a first temperature below the melting point of the phase-change material in the fusible, phase-change powder composition, and
heating the fusible, phase-change powder composition at a second temperature above the melting point of the phase-change material in the fusible, phase-change powder composition and below the glass transition temperature of the composition to form a fused, solid phase-change composition.
19. The article of claim 16 , wherein the cavity has a smallest dimension of greater than the average particle size of the powder and less than 2 centimeters.
20. The article of claim 15 , wherein the article is an electronic device.