B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
B29B15/00—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00
B29B15/02—Pretreatment of the material to be shaped, not covered by groups B29B7/00 - B29B13/00 of crude rubber, gutta-percha, or similar substances