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| | Class Definition for Class 521 - SYNTHETIC RESINS OR NATURAL RUBBERS -- PART OF THE CLASS 520 SERIES |
 | | A polyurea is defined to be a polymer containing the moiety, -NN-, and is generally prepared from either a diamine and a dilsocyanate, a diamine and urea, a diamine and phosgene or a bishaloformate and a diamine. |
 | | Solid polymer as used throughout this schedule does not exclude polymers which would be solid except that under the conditions of use their physical state has been changed to satisfy the process conditions required (e.g., molten, dissolved). |
 | | Furthermore, polymers which are to be after-treated and which already have been exposed to a preliminary after-treatment step, (e.g., halogenated polymer, alkylated polymer, etc.) are classified on the basis of the unsaturated monomers or reactants used in the preparation of the polymer. |
| www.uspto.gov /go/classification/uspc521/defs521.htm (5658 words) |
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