| 摘要 |
1,034,437. Microcapsules. GEVAERT PHOTO-PRODUCTEN N.V. Feb. 20, 1963 [Feb. 20, 1962], No. 6860/63. Heading B8C. Solid particles and liquid droplets of a sparingly water-soluble or water-insoluble material are encapsulated in a mantle of a gelatine derivative which is insoluble in acid aqueous medium but soluble in medium of a higher pH by one of the following methods: (i) The material to be encapsulated is dispersed in an aqueous solution of a gelatine derivative of the said type and the dispersion is acidified to cause the gelatin derivative to coacervate and encapsulate the dispersion particles in a mantle which may be subsequently gelled, e.g. by cooling, and, if desired, hardened, e.g. by treatment with chrome alum. (ii) The material is dispersed in an aqueous solution of gelatin to which a reagent is subsequently added to react with the gelatin to form a derivative of the abovementioned type and which is caused to coacervate by acidification and encapsulate the dispersion, subsequent treatment being as in (i) above. (iii) The material is dispersed in an aqueous dispersion of the gelatin derivative which is already coacervated but not gelled whereby encapsulation of the particles occurs and subsequent treatment being as in (i) above. Suitable gelatine derivatives include the products of the reaction of gelatin with aliphatic and aromatic carboxylic acid anhydrides, compounds containing a reactive halogen atom, e.g. sulphonyl chlorides, sulphonyl fluorides, carbonyl chlorides, carbonyl bromides, chloroformates and other types of compound containing reactive halogen atoms, isocyanates and N-arylvinyl sulphonamides numerous specific examples of such compounds being given. Materials which may be encapsulated include those suitable for use in photography, e.g. N- hex - decyl - 1 - hydroxy - 2 - naphthamide (colour coupler) encapsulated in a gelatinesilver halide emulsion. Other specific examples relate to the encapsulation of paraffin oil, toluene and carbon tetrachloride. |
