PURPOSE: To provide a thermal energy storage element which is safe and inexpensive and does not cause lowering in strength of a container even when thermal energy storage and dissipation are repeated, by enclosing a thermal energy storage material mainly composed of a hydrated salt in a container made of a specified laminated film.
CONSTITUTION: A laminated film which comprises at least one aluminum layer (e.g. aluminum foil layer), a fused layer (e.g. polyethylene layer) and an extruded polyethylene plastic layer (e.g. ethylene/acrylic acid copolymer layer) in contact with the surface of the fused layer side of the aluminum layer is prepd. A container is prepd. from this laminated film, and a thermal energy storage material mainly composed of a hydrated salt such as sodium acetate trihydrate is enclosed in the container to obtain the desired thermal energy storage element which is suitable for use as a warmer.
ISHII TAKAHITO
ISHII KAZUNORI
KOMENO HIROSHI
