Slurry process for the production of absorptive carboxy methyl cellulose fibers

Claim 1

In a slurry process for the production of sodium carboxymethyl cellulose, exhibiting increased absorptive and retentive capacity wherein cellulose is slurried in an aqueous solution of isopropanol and contacted in a first step with sodium hydroxide and the resulting alkali cellulose is contacted with monochloroacetic acid in a second step and thereby etherified to a conventionally soluble d.s. while still slurried in said aqueous solution of isopropanol; the improvement which consists of maintaining a total liquid to cellulose ratio in said steps of about 25 to 40 to 1, by weight, while contacting the cellulose and the alkali cellulose in said steps with about 1.5 moles of sodium hydroxide per mole of monochloroacetic acid and using about 2.2 moles of monochloroacetic acid per mole of anhydroglucose unit of cellulose after neutralization of at least 0.5, to produce an essentially acid product while further maintaining as liquid ratios in said steps, a water to cellulose ratio of about 3.3 to 1, by weight, and an isopropanol to water ratio of about 8 to 1, by weight, while contacting the slurried cellulose with the sodium hydroxide at a slurry temperature of about 5*C. to about 25*C. for a period of about 0.2 to about 0.6 hour and thereafter contacting the thus produced alkali cellulose with the monochloroacetic acid at a slurry temperature of about 60*C. to about 80*C. for a period of about 3 hours to about 12 hours to produce sodium carboxymethyl cellulose exhibiting a d.s. of about 0.4 to about 1.2, a water solubility of less than about 35 percent, a WRV of about 1000 to about 7000 and a SRV of about 400 to about 2,500 is produced.