Radiation curable phase change material solutions and shape stable thermoset phase change material gels formed therefrom
Radiation curable phase change solutions (PCM) and said solutions as a thermoset thermal energy gels (a radiation cured polymeric network) has a hydrophobic PCM, a polybutadiene urethane acrylate oligomer soluble in the hydrophobic PCM and present as 7% wt/wt to 25% wt/wt of the gel, a photoinitiator soluble in the hydrophobic PCM and present as 0.01% wt/wt to 0.5% wt/wt of the gel, a mono-functional or di-functional crosslinker soluble in the hydrophobic PCM and present as 0% wt/wt to 10% wt/wt of the gel, and a hydrogenated styrenic block copolymer as a secondary resin as 0% to 20% wt/wt of the gel and optionally a tertiary resin as 0% to 5% wt/wt of the gel, wherein the tertiary resin is a hydrogenated styrenic block copolymer that is different than the secondary resin. The solution or gel is sealed in a container, e.g., a sachet, to form a cold pack.
1. A thermoset thermal energy gel comprising:
a radiation cured polymeric network formed from
a hydrophobic phase change material;
a polybutadiene urethane acrylate oligomer soluble in the hydrophobic phase change material and present as 7% wt/wt to 25% wt/wt of the thermoset thermal energy gel;
a photoinitiator soluble in the hydrophobic phase change material and present as 0.01% wt/wt to 0.5% wt/wt of the thermoset thermal energy gel; and
a mono-functional crosslinker soluble in the hydrophobic phase change material, present as 0.1% wt/wt to 10% wt/wt of the thermoset thermal energy gel and selected from the group consisting of a mono-functional vinyl caprolactam, an aliphatic monofunctional acrylate, an ethoxylated nonyl-phenol acrylate, an alkoxylated nonyl-phenol acrylate, a 4-tert-butyl cyclohexyl acrylate, and combinations thereof.
2. The thermoset thermal energy gel of claim 1 , wherein the thermoset thermal energy gel is shape stable in that it supports its own weight and after 20 freeze/thaw cycles has weight loss of 1% or less.
3. The thermoset thermal energy gel of claim 2 , wherein the thermoset thermal energy gel is creep resistant up to 60° C.
4. The thermoset thermal energy gel of claim 1 , wherein the polybutadiene urethane acrylate oligomer is a difunctional aliphatic polybutadiene urethane acrylate oligomer.
5. 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.
6. The thermoset thermal energy gel of claim 5 , wherein the n-alkane is saturated and has an amount of carbon atoms within the range of C 10 -C 40 .
7. The thermoset thermal energy gel of claim 1 , wherein the photoinitiator comprises phosphine oxide.
8. The thermoset thermal energy gel of claim 1 , wherein when the mono-functional crosslinker is present as 0.1% wt/wt to 1% wt/wt of the thermoset thermal energy gel, the polybutadiene urethane acrylate oligomer is present as 18% wt/wt to 21% wt/wt of the thermoset thermal energy gel.
9. The thermoset thermal energy gel of claim 1 , wherein a balance is the hydrophobic phase change material is present in an amount of a balance of the thermoset thermal energy gel.
10. The thermoset thermal energy gel of claim 1 , further comprising a hydrogenated styrenic block copolymer as a secondary resin as 0.5% to 20% wt/wt of the thermoset thermal energy gel.
11. The thermoset thermal energy gel of claim 10 , further comprising a tertiary resin as 0.5% to 5% wt/wt of the thermoset thermal energy gel, wherein the tertiary resin is a hydrogenated styrenic block copolymer that is different than the secondary resin.
12. The thermoset thermal energy gel of claim 11 , wherein the tertiary resin is present as 1% to 2% wt/wt of the thermoset thermal energy gel and the secondary resin is present as 1% to 10% wt/wt of the thermoset thermal energy gel.
13. The thermoset thermal energy gel of claim 12 , wherein the secondary resin and the tertiary resin are both styrene-ethylene-butylene-styrene linear polymers with tri-block structures.
14. A radiation curable phase change solution comprising:
a hydrophobic phase change material;
a radiation curable polybutadiene urethane acrylate oligomer soluble in the hydrophobic phase change material and present as 7% wt/wt to 25% wt/wt of the radiation curable phase change solution;
a photoinitiator soluble in the hydrophobic phase change material and present as 0.01% wt/wt to 0.5% wt/wt of the radiation curable phase change solution; and
a mono-functional or di-functional crosslinker soluble in the hydrophobic phase change material and present as 0.1% wt/wt to 10% wt/wt of the radiation curable phase change solution;
wherein upon exposure to radiation the radiation curable phase change solution cures to form a thermoset gel;
wherein the radiation curable phase change solution comprises less than 30% solids and has a viscosity less than 5000 cP at 60° C.
15. The radiation curable phase change solution of claim 14 , wherein the polybutadiene urethane acrylate oligomer is a difunctional aliphatic polybutadiene urethane acrylate oligomer.
16. The radiation curable phase change solution of claim 14 , 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.
17. The radiation curable phase change solution of claim 16 , wherein the n-alkane is saturated and has an amount of carbon atoms within the range of C 10 -C 40 .
18. The radiation curable phase change solution of claim 14 , wherein the photoinitiator comprises phosphine oxide.
19. The radiation curable phase change solution of claim 14 , wherein the crosslinker is a mono-functional crosslinker, and the mono-functional crosslinker comprises a mono-functional vinyl caprolactam, a mono-functional lauryl acrylate, a mono-functional isobornyl acrylate, an aliphatic monofunctional acrylate, an ethoxylated nonyl-phenol acrylate, an alkoxylated nonyl-phenol acrylate, or a 4-tert-butyl cyclohexyl acrylate.
20. The radiation curable phase change solution of claim 14 , wherein the crosslinker is a di-functional crosslinker, and the di-functional crosslinker comprises a di-functional 1,6-hexanediol diacrylate, di-functional 3-methyl-1,5-pentanediol diacrylate, hydroxy pivalic acid neopentyl glycol diacrylate, or 2-butyl-2-ethyl 1,3-propanediol diacrylate.
21. The radiation curable phase change solution of claim 14 , wherein the hydrophobic phase change material is present in an amount of a balance of the radiation curable phase change solution.
22. The radiation curable phase change solution of claim 14 , further comprising a hydrogenated styrenic block copolymer as a secondary resin as 0.5% to 20% wt/wt of the radiation curable phase change solution.
23. The radiation curable phase change solution of claim 22 , further comprising a tertiary resin as 0.5% to 5% wt/wt of the radiation curable phase change solution, wherein the tertiary resin is a hydrogenated styrenic block copolymer that is different than the secondary resin.
24. The radiation curable phase change solution of claim 23 , wherein the tertiary resin is present as 1% to 2% wt/wt of the radiation curable phase change solution and the secondary resin is present as 1% to 10% wt/wt of the radiation curable phase change solution.
25. The radiation curable phase change solution of claim 24 , wherein the secondary resin and the tertiary resin are both styrene-ethylene-butylene-styrene linear polymers with tri-block structures.
26. A cold pack comprising:
a container sealingly enclosing the thermoset thermal energy gel of claim 1 .
27. The cold pack of claim 26 , wherein the container permanently encloses the thermoset thermal energy gel.
28. The cold pack of claim 26 , wherein the container is a rigid container that retains a preselected shape and configuration.
29. The cold pack of claim 26 , wherein the container is a flexible container that is conformable to the surface against which the flexible container is seated.