crepe rubber vs natural rubber

crepe rubber and natural rubber both are nouns.

Word	Noun	Adjective	Verb	Adverb
crepe rubber	Yes	No	No	No
natural rubber	Yes	No	No	No

As nouns, natural rubber is a hypernym of crepe rubber; that is, natural rubber is a word with a broader meaning than crepe rubber:

crepe rubber: crude natural rubber; used mainly for shoe soles
natural rubber: an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products

Other hypernyms of crepe rubber include caoutchouc, gum elastic, India rubber, rubber.

crepe rubber (noun)	natural rubber (noun)
crude natural rubber; used mainly for shoe soles	an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products