Method of drying a material having a cohesive phase
AssigneeGenzyme Corporation
InventorGary S. Rea
Life of this patent
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Abstract
A method for drying a material such as a polymer hydrogel which passes through a cohesive phase as it dries is disclosed. The method comprises agitating a composition while removing liquid until the solids content of the composition reaches a level at which the composition enters a cohesive phase, halting agitation, removing liquid from the composition in the absence of agitation, and resuming agitation. Practice of the present invention can eliminate the problems associated with adhesion of a material to itself and to process equipment during the cohesive phase.
Claims14
1-36. (canceled)
A method of removing liquid from a composition comprising:
- a. agitating the composition while removing liquid until the composition enters a cohesive phase;
- b. halting agitation;
- c. removing liquid from the composition in the absence of agitation until the composition passes through the cohesive phase;
- d. resuming agitation;
- and
- e. removing liquid from the composition while agitating the composition until the solids content of the composition reaches a pre-determined level, wherein said composition comprises a polymer.
The method of 37, wherein said polymer is a cross-linked polymer.
The method of 37, wherein said polymer comprises a repeat unit having the formula
- wherein a and b are the number of primary amine groups and a+b is about 9, c is the number of cross-linking groups and c is about 1, n is the fraction of protonated amines and n is about 0.4 and m is an integer.
The method of 39, wherein said composition is agitated at a pressure P1 and the liquid is removed from the composition in the absence of agitation at a pressure P2, wherein P2 is less than P1.
Dependencies are inferred from the claim text.