| 摘要 |
PURPOSE:Removal of residual formaldehyde resulting from the formation of microcapsule with the wall membrane of urea-formaldehyde resin, etc. by reacting the residual formaldehyde with saccharide under a specified condition. CONSTITUTION:Microdroplets emulsified in a liquid vehicle are encapsulated with the wall membrane of urea-formaldehyde or melamine-formaldehyde resin to form microcapsules. An excess amount of formaldehyde used is reacted with five members of saccharides such as glucose, fructose, glycerine aldehyde, etc. at a temperature of 20 to 50 deg.C, at a pH of 11 to 12.5 in the presence of a hydroxide of alkali metal such as lithium, sodium, etc. to remove the excess formaldehyde, said alkal; metal hydroxide acting as a catalyst and alkalinity-adjusting agent. The reaction products of formaldehyde with saccharides are harmless and do not deteriorate the quality of the obtained microcapsules. |
