Process for making filament tobacco smoke filters

Claim 1

IN A PROCESS OF MAKING TOBACCO SMOKE FILTER ELEMENTS COMPRISING OF CRIMPED CONTINUOUS CELLULOSE ACETATE FILAMENTS OF A DENIER OF FROM 0.5 TO 16 WHICH ARE WRAPPED IN A PAPER WRAPPER, THE IMPROVEMENT WHICH COMPRISES APPLYING PARTIALLY ACROSS THE INNER SURFACE OF THE PAPER WRAPPER AS A SOLUTION A LIQUID-DOPE COATING COMPOSITION WITHOUT ADHESIVE ABILITY WHEN APPLIED, SAID LIQUID-DOPE COATING COMPOSITION CONSISTING OF 1-4% BY WEIGHT SOLID CELLULOSE ESTER DISSOLVED IN 96-99% BY WEIGHT LIQUID TRIACETIN, THE PAPER WRAPPER BEING OF A THICKNESS OF THE ORDER OF 0.03 TO 0.06 MM., AND THEN CONTACTING THE SURFACE FILAMENTS OF THE ELEMENT WITH SAID LIQUID-DOPE COATING COMPOSITION APPLIED TO SAID PAPER WRAPPER DURING THE WRAPPING OPERATION AND BONDING THE SURFACE FILAMENTS TO THE PAPER WRAPPER WITH ABSORPTION OF LIQUID TRIACETIN BY THE FILAMENTS.