Phase change compositions

A process for preparing a thermodynamically stable aqueous liquid composition containing crystalline sodium acetate trihydrate as a phase change material which is resistant to the nucleation of crystalline sodium acetate on heating and cooling, the process comprising the steps of:

• a) mixing an aqueous solution comprising sodium acetate anhydrous with the one or more alkali soluble polymers and, optionally, water to form a mixture;
• and
• b) heating the mixture to at or above 58° C. to provide a phase change material containing crystalline sodium acetate trihydrate, wherein the aqueous solution may optionally include an agent for modifying the melting point of sodium acetate;
• and
• wherein the aqueous solution comprises:
• from 40% to 60% of sodium acetate anhydrous;
• from 0.1% to 10% of at least one suitable alkali soluble polymer;
• from 0.1% to 5% of at least one suitable nucleation promoter;
• optionally, from 1% to 25% of a melting point depressing agent;
• and
• water to balance.