Polymer composition and its use as a phase change material

Patent metadata

Field	Value
Publication number	US-11208544-B2
Application number	US-201716332863-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Sep 28, 2016
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

A polymer composition comprising: (a) from 50% by volume to 99% by volume, preferably from 70% by volume to 95% by volume, of at least one homopolymer or copolymer of ethylene; (b) from 1% by volume to 50% by volume, preferably from 5% by volume to 30% by volume, of at least two fillers having different thermal conductivity; (c) from 100 ppm to 4000 ppm, preferably from 200 ppm to 3500 ppm of at least one fluoropolymer; the sum of (a)+(b) being 100. Said polymer composition can be used as a phase change material (PCM), in particular for thermal energy storage (TES), more in particular for the storage of solar energy.

First claim

The invention claimed is:

1. A phase change material that is adapted for thermal energy storage, comprising a polymer composition comprising:
(a) from 80% by volume to 99% by volume of at least one homopolymer or copolymer of ethylene;
(b) from 1% by volume to 20% by volume of at least two fillers having different thermal conductivity: (b 1 ) fillers having a thermal conductivity lower than or equal to 15 W/mK; (b 2 ) fillers having a thermal conductivity higher than or equal to 50 W/mK;
from 100 ppm to 4000 ppm of at least one fluoropolymer;

wherein said at least one homopolymer or copolymer of ethylene and said at least one fluoropolymer, are the only (co)polymers of the composition, and the sum of (a)+(b) is 100.

2. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 , wherein said homopolymer or copolymer of ethylene is selected from:
high-density polyethylene (HDPE);
medium-density polyethylene (MDPE);
low-density polyethylene (LDPE);
linear-low-density polyethylene (LLDPE), very-low-density polyethylene (VLDPE), ultra-low-density polyethylene (ULDPE), which are copolymers of ethylene with at least one aliphatic α-olefin having the formula CH 2 ═CH—R in which R represents a linear or branched alkyl group containing from 1 to 12 carbon atoms, selected from: propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene;
or mixtures thereof.

3. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 , wherein said fillers (b 1 ) are selected from: talc H 2 Mg 3 (SiO 3 ) 4 , calcium carbonate (CaCO 3 ), magnesium hydroxide [Mg(OH) 2 ], mica, barium oxide (BaO), boehmite [g-AlO(OH)], diaspore [g-AlO(OH)], gibbsite [Al(OH) 3 ], barium sulfate (BaSO 4 ), wollastonite (CaSiO 3 ), zirconium oxide (ZrO 2 ), silicon oxide (SiO 2 ), glass fiber, magnesium aluminate [MgO x Al 2 O 3 in which x=from 1.5 to 2.5], dolomite [CaMg(CO 3 ) 2 ], clay, hydrotalcite, or mixtures thereof.

4. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 , wherein said fillers (b 2 ) are selected from: boron nitride (BN), aluminum nitride (AlN), magnesium silicon nitride (MgSiN 2 ), silicon carbide (SiC), graphite, ceramic coated graphite, expanded graphite, graphene, carbon fiber, carbon nanotubes (CNT), graphitized carbon black, or mixtures thereof.

5. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 , wherein said fillers (b 1 ) and said fillers (b 2 ) have:
an aspect ratio, said aspect ratio being defined as the ratio between the diameter and the thickness of said fillers, ranging from 5 to 1000; and/or
at least one of the three dimensions ranging from 0.1 μm to 1000 μm.

6. Polymer composition according to claim 1 , wherein said at least one filler (b 1 ) and said at least one filler (b 2 ) are present in a ratio by volume ranging from 4:1 to 1:2.

7. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 , wherein said fluoropolymer (c) is selected from fluoroelastomers, mixtures comprising a fluoroelastomer and an ethylene (co)polymer, masterbatches comprising a fluoroelastomer and a (co)polymer of ethylene.

8. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 comprising from 200 ppm to 3500 ppm of said at least one fluoropolymer.

9. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 wherein said fillers (b1) have a thermal conductivity ranging from 1 W/mK to 10 W/mK and said fillers (b 2 ) have a thermal conductivity ranging from 80 W/mK to 500 W/mK.

10. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 5 wherein said fillers (b 1 ) and said fillers (b 2 ) have:
said aspect ratio ranging from 10 to 500; and/or said at least one of the three dimensions ranging from 3 μm to 500 μm.

11. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 , wherein said at least one filler (b 1 ) and said at least one filler (b 2 ) are present in a ratio by volume ranging from 2:1 to 1:1.

12. A phase change material that is adapted for thermal energy storage, comprising a polymer composition according to claim 1 wherein said at least one fluoropolymer does not reduce a thermal conductivity of said polymer composition.

Assignees

• Versalis Spa

Inventors

• Castiglioni Andrea
• Scavello Francesco
• Balducci Daniele
• Mariani Paolo

Classifications

• C08K2003/385

  Binary compounds of nitrogen with boron · CPC title

• C08L2207/062

  HDPE · CPC title

• C09K5/14

  Solid materials, e.g. powdery or granular · CPC title

• C08L23/06 Primary

  Polyethylene · CPC title

• C08L27/12

  containing fluorine atoms · CPC title