US PATENT SUBCLASS 521 / 159-- .~.~.~ N=C=X reactant having at least two C-NH-C(=X)- groups, e.g., prepolymers, etc.

US PATENT SUBCLASS 521 / 159
.~.~.~ N=C=X reactant having at least two C-NH-C(=X)- groups, e.g., prepolymers, etc.

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}
50	DF	.~ CELLULAR PRODUCTS OR PROCESSES OF PREPARING A CELLULAR PRODUCT, E.G., FOAMS, PORES, CHANNELS, ETC. {27}
155	DF	.~.~ Cellular product derived from a -N=C=X containing reactant wherein X is a chalcogen atom {10}
159		.~.~.~ N=C=X reactant having at least two C-NH-C(=X)- groups, e.g., prepolymers, etc.

DEFINITION

Classification: 521/159

N=C=X reactant having at least two C- - groups, e.g., prepolymers, etc.:

(under subclass 155) Subject matter wherein the -N=C=X (X is chalcogen) reactant contains at least two C-NH groups.

(1) Note. Patents for the most part herein concern the after treatment of a prepolymer having a terminal -N=C=X group.

SEE OR SEARCH THIS CLASS, SUBCLASS:

155, through 158 and 160 through 177, for products and processes where a prepolymer is inherently prepared in an ongoing polymerization reaction and is subsequently modified, but where no intent has been made to recognize or identify the prepolymer intermediate.