Process for the manufacture of surfactant cleansing blocks and compositions thereof

DETAILED DESCRIPTION OF THE INVENTION By way of definition, the term "block" as used herein means formed, solid composition of matter articles obtained in accordance with the processes described herein.
"Hydrated cellulose" means a cellulosic material, preferably hydroxyalkyl cellulose, that has sorbed a hydroxy-containing compound whose hydroxy groups are available for sorption.
"Curing" means the substantial hardening of the soft homogeneous blend of admixed constituents comprising the block subsequent to the termination of shear forces acting thereon.
The blocks of the present invention comprise a hydrated cellulose material and surfactant.
It has been found that hydration of the cellulose material prior to blending with anhydrous surfactant or with an organic oil (including organic fragrance oils) is advantageous in several respects, and overcomes certain processing difficulties inherent in the manufacture of surfactant containing cleansing blocks, particularly cleansing blocks manufactured by extrusion.
Firstly, hydration of the cellulose, which acts as a binder to retain the shape of the blocks of the present invention when they are immersed in aqueous media, improves handleability of the blend of constituents comprising the block during the latter stages of the manufacturing process.
This is especially important in extrusion of the homogeneous blend.
Hydration accelerates curing of the block thereby permitting high speed extrusion and on-line cutting of the extrudate.
It has been found that blocks manufactured with hydroxyalkyl cellulose that has not been hydrated have a tendency, when placed in aqueous media, to swell, it is believed as a consequence of water absorption, the swelling deleteriously affecting block integrity.
Hydrated hydroxyalkyl cellulose blocks, on the other hand, have reduced tendency to swell and deteriorate resulting in longer-lived blocks.
Finally, it has been found that the degree of hydration of the hydrated hydroxyalkyl cellulose is a variable that may be regulated to provide flexibility in process operation and/or product characteristics