Coated fabrics, which typically include polyvinyl chloride (PVC) or vinyl, on such fabrics as cotton, nylon, rayon, polyester and combinations thereof are found in a variety of finished products including automotive upholstery, furniture, wallpaper and luggage. In the bonding of the sheet vinyl to the fabric scrim, the fabricator trims the edges before the coated fabric is shipped to the end user. Today, it has been estimated that among the major manufacturers of vinyl coated fabrics, tens of millions of pounds of PVC are lost because there is no economical way to separate the vinyl from its fabric backing.
Chemical methods for achieving this separation, i.e., processes described and claimed in U.S. Pat. Nos. 3,624,009; 3,836,486; and 3,873,411, have to date not been considered to be economical processes for the recovery of PVC.
There have been an increasing number of prior art recovery processes employing cryogenic embrittlement; see U.S. Pat. Nos. 2,879,005; 3,614,001; 3,666,185; 3,718,284; 3,768,739; 3,885,744; 3,749,322; 4,020,992, 4,025,990 and 4,251,034 as well as the relevant references cited therein.
The prior art cryogenic processes have been effective to embrittle the thermoplastic coating and to liberate the thermoplastic from the material on which the plastic is bonded. However, all of the prior art processes, whether taken alone or in combination, have neither disclosed nor suggested a viable means for separating thermoplastic from the fabric after such liberation.
Specifically, it has been found that a very poor recovery of PVC is obtained by a combination of the cryogenic grinding, impacting and screening steps disclosed in U.S. Pat. No. 2,879,005 or U.S. Pat. No. 4,020,992 with the air separating means disclosed in U.S. Pat. No. 3,885,744.