| abstract |
A heat pack capable of being heated to at least 55° C. is provided and includes a flexible impervious outer container capable of being sealed to retain a liquid such as water therein and of maintaining its sealed integrity when heated to at least the aforesaid temperature. A porous, non-rigid filing material, which can absorb at least its own weight of the liquid, is located in the container. Advantageously, the pack contains a weight of liquid in the range 250 goods to 1250 goods, which liquid is water or compounds having one or more hydroxyl groups, or a mixture of water and such hydroxyl group compounds. In order to prevent microbial growth within the liquid-filled, sealed container, a predetermined quantity of a preservative at an appropriate concentration is also added to the fill. The filling material is preferably either fibrous or spongy in nature and advantageously may be a textile material or paper which is either recycled or would otherwise be treated as scrap or waste. Preferably also, air is removed from the outer container prior to it being sealed. The pack is also capable of use as a negative heat pack, i.e. a cool pack. |