RADIATION CURABLE PHASE CHANGE MATERIAL SOLUTIONS AND SHAPE STABLE THERMOSET PHASE CHANGE MATERIAL GELS FORMED THEREFROM
Thermoset thermal energy gels having a radiation cured polymeric network are formed from a hydrophobic phase change material (PCM); (a) 1% wt/wt to 15% wt/wt of a polybutadiene based rubber polymer that is soluble in the PCM and has (i) a pendant 1,2 vinyl content of at least 0.5% wt/wt thereof or (ii) a 1,4 cis content of at least 9.0% wt/wt; or (iii) a combination of 1,2 vinyl content plus a 1,4 cis content of at least 45% wt/wt; or (b) 1% wt/wt to 15% wt/wt of a polyisoprene based rubber polymer that is soluble in the PCM and has (i) a combination of 1,2 Add plus 3,4 Add content of at least 0.5% wt/wt thereof or (ii) a combination of 1,4 cis content plus a 1,4 trans content of at least 40% wt/wt; and 0.01% wt/wt to 0.50% wt/wt of a photoinitiator soluble in the PCM.
1 . A thermoset thermal energy gel comprising:
a radiation cured polymeric network formed from
a hydrophobic phase change material;
(a) 1% wt/wt to 15% wt/wt of a polybutadiene based rubber polymer that is soluble in the hydrophobic phase change material and has (i) a pendant 1,2 vinyl content of at least 0.5% wt/wt thereof or (ii) a 1,4 cis content of at least 9.0% wt/wt; or (iii) a combination of 1,2 vinyl content plus a 1,4 cis content of at least 45% wt/wt; or
(b) 1% wt/wt to 15% wt/wt of a polyisoprene based rubber polymer that is soluble in the hydrophobic phase change material and has (i) a combination of 1,2 Add plus 3,4 Add content of at least 0.5% wt/wt thereof or (ii) a combination of 1,4 cis content plus a 1,4 trans content of at least 40% wt/wt; and
0.01% wt/wt to 0.50% wt/wt of a photoinitiator soluble in the hydrophobic phase change material;
wherein the hydrophobic phase change material is the balance thereof.
2 . The thermoset thermal energy gel of claim 1 , wherein the polybutadiene based rubber polymer or the polyisoprene based rubber polymer is present as 1% to 10% wt/wt of the thermoset thermal energy gel.
3 . The thermoset thermal energy gel of claim 1 , wherein the polybutadiene based rubber polymer is a polybutadiene rubber, a styrene butadiene rubber, or a styrene butadiene styrene rubber.
4 . The thermoset thermal energy gel of claim 1 , wherein the polybutadiene based rubber polymer is (a) a high vinyl 1,2-polybutadiene atactic linear polymer with a vinyl content of 77%, with a Tg of −31° C. and a Mooney viscosity (ML (1+4), 100° C.) of 70, (b) a high vinyl 1,2-polybutadiene polymer that is syndiotactic, with a Mw of 100,000 g/mol a melting point of 71° C., and a 1,2-polybutadiene vinyl content of 90% wt/wt, or (c) a random copolymer high vinyl solution polymerized styrene butadiene rubber (S-SBR), with a styrene content of 15% to 21% wt/wt, a 1,2-vinyl content of 48% to 68% with respect to polybutadiene, and a Mooney viscosity between 58 and 75.
5 . The thermoset thermal energy gel of claim 1 , wherein the polyisoprene based rubber polymer is a polyisoprene rubber, a copolymer of polyisoprene and polybutadiene rubber, or a styrene isoprene styrene rubber.
6 . The thermoset thermal energy gel of claim 3 , wherein the rubber polymer has a dissolution point, in the hydrophobic phase change material, of equal to or less than 100° C.
7 . The thermoset thermal energy gel of claim 3 , wherein the rubber polymer has a dissolution point in the hydrophobic phase change material, of equal to or less than 75° C.
8 . The thermoset thermal energy gel of claim 3 , wherein the rubber polymer has a dissolution point, in the hydrophobic phase change material, in a range of 30° C. to 40° C.
9 . The thermoset thermal energy gel of claim 3 , wherein the rubber polymer is a syndiotactic butadiene rubber.
10 . The thermoset thermal energy gel of claim 3 , wherein the rubber polymer is a 1,4 cis butadiene rubber having a 1,4 cis content of between 35% to 40% wt/wt.
11 . The thermoset thermal energy gel of claim 3 , wherein the rubber polymer is a 1,4 cis butadiene rubber having a 1,4 cis content of at least 90% wt/wt.
12 . The thermoset thermal energy gel of claim 1 , wherein the hydrophobic phase change material is selected from the group consisting of an n-alkane, a fatty acid methyl ester, a fatty alcohol, a fatty acid, and mixtures thereof.
13 . The thermoset thermal energy gel of claim 12 , wherein the n-alkane is saturated and has carbon atoms within the range of C 10 -C 30 and the fatty acid methyl ester has carbon atoms within the range of C 12 -C 16 .
14 . The thermoset thermal energy gel of claim 1 , wherein the photoinitiator comprises phosphine oxide.
15 . The thermoset thermal energy gel of claim 1 , comprising a hydrogenated styrenic block copolymer as a secondary resin as 0.5% to 15% wt/wt of the gel.
16 . The thermoset thermal energy gel of claim 15 , wherein the hydrogenated styrenic block copolymer is fully hydrogenated and is selected from the group consisting of a styrene-ethylene-propylene (SEP) polymer, a styrene-ethylene-propylene-styrene (SEPS) polymer, a styrene-ethylene-ethylene-propylene-styrene (SEEPS) polymer, a styrene-ethylene-butylene-styrene (SEBS) polymer, a SEBS with an enhanced rubber segment (ERS), a styrene-ethylene butylene/styrene-styrene (S-EB/S-S) polymer, and combinations thereof.
17 . The thermoset thermal energy gel of claim 15 , wherein the hydrogenated styrenic block copolymer is a diblock SEP.
18 . The thermoset thermal energy gel of claim 17 , wherein the diblock SEP has styrene as 25% to 40% wt/wt thereof and is 100% diblock in structure.
19 . The thermoset thermal energy gel of claim 15 , wherein the hydrogenated styrenic block copolymer is a diblock or triblock copolymer.
20 . A radiation curable phase change solution comprising:
a hydrophobic phase change material;
(a) 1% wt/wt to 15% wt/wt of a polybutadiene based rubber polymer that is soluble in the hydrophobic phase change material and has (i) a pendant 1,2 vinyl content of at least 0.5% wt/wt thereof or (ii) a 1,4 cis content of at least 9.0% wt/wt; or (iii) a combination of 1,2 vinyl content plus a 1,4 cis content of at least 45% wt/wt; or
(b) 1% wt/wt to 15% wt/wt of a polyisoprene based rubber polymer that is soluble in the hydrophobic phase change material and has (i) a combination of 1,2 Add plus 3,4 Add content of at least 0.5% wt/wt thereof or (ii) a combination of 1,4 cis content plus a 1,4 trans content of at least 40% wt/wt; and
0.01% wt/wt to 0.50% wt/wt of a photoinitiator soluble in the hydrophobic phase change material;
wherein the hydrophobic phase change material is the balance thereof, and upon exposure to radiation the composition cures to form a thermoset gel.
21 . A cold pack comprising:
a container sealingly enclosing the thermoset gel of claim 1 .
22 . The cold pack of claim 21 , wherein the container is a rigid container that retains a preselected shape and configuration or the container is a flexible container that is conformable to a surface against which the flexible container is seated.