Process for preparing water sorptive products
The present invention is directed to a process for preparing cellulose containing water sorptive products from an aqueous suspension or paper furnish in accordance with conventional paper making techniques. The suspension or paper furnish employed in preparing the sorptive products comprises a polymer component and a fibrous component slurried in water. The polymer component is provided from a specifically defined class of crosslinked copolymers which contain carboxyl groups. A representative polymer from this class includes that obtained by reacting methyl acrylate and methacrylate acid in the presence of ethylene glycol dimethacrylate. The polymer component becomes water sorptive when the carboxyl groups present thereon are neutralized with a base. In the practice of the process of the present invention, a composite product is prepared from the above mentioned suspension, partially dried, and then neutralized in a specifically controlled manner. Neutralization is achieved while controlling the amount of base and water which contacts the composite product. The control is exercised in a manner sufficient to achieve a proper degree of salting and to prevent undue sorption of the water during neutralization. Such control results in a substantial improvement in the cost efficiency of the process since the amount of water which must be eventually evaporated from the neutralized product is held to a minimum.