Patent GB-1370670-A (GB)
Title: Method and apparatus for the manufacture of variegated soap bars
IPC: B29C48/06
Filed: 1971-12-15
Abstract: 1370670 Extruding variegated soap .COLGATE-PALMOLIVE CO 15 Dec 1971 [29 Dec 1970] 58322/71 Heading B5A [Also in Division C5] A soap bar 13, Fig. 2, is extruded with a variegated appearance which may comprise a marbling, or a more striped dispersion of soap 131, Fig. 9, of one colour within a base soap 133 which is uncoloured, or of a different colour. The soap bar 13 is extruded from the die 57 of a plodder 19 which, at a vacuum chamber inlet 35 thereof, is supplied with pieces 33, 31 of each soap respectively cut by rotary knives 49, 29 at the multiple orifice outlets 45, 15 of screw plodders 17, 15. The extruded bar may be shaved to enhance the variegated effect, by knives 115, Fig. 5, prior to cooling or drying, followed by cutting and pressing to form a tablet. The plodders 19, 17, 15 and the chamber 35 one provided with jackets through which cooling or heating water is circulated. The inlet end of the screw 55 of plodder 19 may have a shallower pitch and greater thread depth than at its downstream end. The chamber 35 may have a window 67 or automatic means to detect and maintain, by alteration of the plodder screw speeds, a required level of the soap pieces 53 at the inlet end of the screw 55, e.g. to 30 to 70% of the screw depth. The soap is subject to transverse compression in a conical inlet chamber 59 to the die 57 and a perforate pressure plate at the inlet to chamber 57 may be employed to produce a soap bar of a more striped appearance. The compression chamber and die are preferably of a length less than half the diameter of the screw 55, and may be defined, Fig. 4 (not printed), between outer arcuately tapering walls and a conical projection from a perforate pressure plate. Alternatively, Fig. 5, a pressure chamber 105 may be employed to which the soap is delivered through pressure plate openings 103 from which it is cut by a rotary knife 109 driven by a shaft 111 from the screw 55, the knife blades also effecting a transverse displacement of the cut soap to produce a marbelised, rather than a striped appearance and which effect may be modified by pressure plate openings of differing size, number and arrangement, and by from 1 to 12, and preferably 2 to 5, radially extending blades of the rotary knife. The pressure plate and cutter may be located at the downstream end of the compression chamber, and followed by a further compression section. The soap producing the variegated effect is present in an amount of 3 to 49% by weight, preferably 5 to 20%, or 3 to 25%, and is made more plastic than the base soap by the addition of more water, or a plasticising substance of which a number are specified. The soaps may comprise synthetic detergents, mainly solid specified anionic or non-anionic, but also minor proportions of amphoterics and cationics. Preferably, synthetic detergents comprise minor proportions of the soaps, which may include water-insoluble soap, e.g. magnesium stearate. The soap may include less than 10%, e.g. less than 5%, of adjuvenants, although up to 40% may be included with synthetic detergents. Four examples are given relating to specified soap compositions, comprising uncoloured, or white, base soaps variegated with green, pink, blue, or red soap, and with a base soap being of a non-white colour lighter in shade than a contrasting variegating colour.