| abstract |
PURPOSE: To prevent the generation of crazing and contracture by swelling the collagen sponge by an aq. soln. of a hydrophilic org. solvent, then subjecting the sponge to freeze drying. n CONSTITUTION: The collagen sponge is immersed in a soln. of the hydrophilic org. solvent of 15% concn. and is substd. with distilled water and thereafter, this sponge is rapidly frozen in a cryogenic refrigerator kept at -80°C. After this sponge is completely frozen, the sponge is subjected to the freeze drying in a vacuum freeze drying device to complete the treatment. The hydrophilic org. solvent used in this embodiment refers to alcohols, such as methanol, ethanol and propanol, and lower ketones and is most adequately, particularly in terms of safety, ethanol. The generation of the crazing and the contracture is prevented in this way. n COPYRIGHT: (C)1991,JPO&Japio |