| 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} |
| 99 | DF | .~.~ Cellular product formation prior to or during solid polymer formation in the presence of a stated ingredient other than water {18} |
| 123 | | .~.~.~ Ingredient contains a metal atom {1} |
| 124 | DF | .~.~.~.~> Metal atom is part of an organic compound {2} |