My guess is that the material is really trivial, and they're just trying to protect the composition so they can get a lead to market. Once it's on the market, I

My guess is that the material is really trivial, and they're just trying to protect the composition so they can get a lead to market. Once it's on the market, I bet it'll be cracked open within days, and cloned fast. My guess? The phase change material could be as simple as beeswax. (Melting point of 62-64 C, very close to the melting point they specify.) They'd want to optimize for heat capacity, but there are plenty of natural and safe materials in the ballpark.