US PATENT SUBCLASS 521 / 27-- .~.~ Membrane or process of preparing

US PATENT SUBCLASS 521 / 27
.~.~ Membrane or process of preparing

Current as of: June, 1999
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521 /	HD	SYNTHETIC RESINS OR NATURAL RUBBERS -- PART OF THE CLASS 520 SERIES

*	DD	SYNTHETIC RESINS (Class 520, Subclass 1) {3}
25	DF	.~ ION-EXCHANGE POLYMER OR PROCESS OF PREPARING {7}
27		.~.~ Membrane or process of preparing

DEFINITION

Classification: 521/27

(under subclass 25) Subject matter wherein the ion-exchange polymer is in the form of a membrane.

(1) Note. By membrane is meant a thin sheet or film generally having some degree of permeability, and which may be homogenous or heterogeneous in structure, and the the latter case the ion-exchange material is a component of a composition.

SEE OR SEARCH CLASS

210, Liquid Purification or Separation,

500.21, (2) Note for the lines between this class (521) and other classes with respect to membranes defined by composition.