GB608943A - Improvements in or relating to manufacture of soap - Google Patents

Abstract

<PICT:0608943/III/1> An aqueous saponifying reagent and a fat are passed continuously through a series of mixing compartments maintained at a saponifying temperature and the conditions of saponification are adapted in each compartment to maintain a saponified mixture in which the degree of saponification of the available fatty acid is either below 70 or above 85 per cent. The degree of saponification in each compartment is determined, for example, by the temperature and time during which the reagents are together in the compartment. The saponification may be carried out so that less than 70 per cent of the available fatty acid is saponified in the first compartment, and in a subsequent compartment the degree of saponification is raised to over 85 per cent. Alternatively, saponification in excess of 85 per cent may be effected in the first compartment. In order to obtain effective utilization of the aqueous saponifying reagent, a further quantity of fat may be fed into a compartment downstream from the compartment in which p saponification has proceeded to an extent in excess of 85 per cent, provided that the degree of saponification is not brought within the range 70 to 85 per cent. For example, in Fig. 5, fat from container 110 is passed in confluence with lye from container 111 into the first compartment 116 of the mixer 114 provided with a heating coil 120, wherein saponification occurs to an extent in excess of 85 per cent of the available fatty acid. Brine may also be fed into the compartment 116 from container 122 in order to grain the soap as it is formed. Coils 120 in compartments 117, 118 and 119 may be used to cool the soap before it enters the centrifuge 121. A further quantity of fat may be introduced into 117 through pipe-line 126 to utilize excess lye contained in the soap, but insufficient to produce a mixture in which less than 85 per cent of the available fatty acid is saponified. In a modification, the fat fed from container 110 may be a mixture of soap and fat derived from the first stage of a multi-stage process in which saponification has proceeded to an extent corresponding to less than 70 per cent utilization of the available fatty acid. Specifications 549,386 and 549,387 are referred to.