Crosslapped needlepunched carpeting consists of two main types, one containing polypropylene and the other polyester, as the main fiber constituents.
In the manufacture of such carpeting, there is unavoidable trim waste, totaling 4.
The majority of this carpeting, approximately 80%, is made of polypropylene and contains a polyvinyl acetate copolymer latex as a binder.
Use of polyethylene fiber increases the overall integrity and strength of the carpeting and has the advantage of being able to be blended in dry form with the polypropylene fiber while it is being formed into carpeting.
The objective of this work was to find a feasible way of recycling polypropylene carpet waste into a meltable, thermo-formable backcoating for polyester carpeting so that the back-coated carpeting could be molded for use as an automotive trunk liner.
This processing consisted of three essential steps: 1) reduction of the polypropylene waste carpeting to a different form and particle size for further processing, 2) application of the waste to the back of polyester carpeting by either a powder or a flock applicator and 3) melting and fusing the applied waste into a film and bonding it to the back of the polyester carpeting so that it could be reactivated and the carpeting thermally formed in a subsequent molding step.
A) a carpeting containing a crosslinked polyvinyl acetate copolymer latex as the binding component.
B) a carpeting containing polyethylene binder fiber instead of polyvinyl acetate as the binding component and
C) a trial carpeting containing a non-crosslinked polyvinyl acetate copolymer latex as the binding component.
Performing this process on the carpeting containing crosslinked latex resulted in a blend of fibers interlocked with hard opaque particles.
Melting and fusing trial: Small hand application and fusing trials performed by depositing the granulated waste onto the back of polyester carpeting and heating at 350 [degrees] F resulted in melting of the waste but no coalescing into a coherent film.
Powder application trial: Use of a powder applicator (consisting of a rotating gravure roll and a doctor blade on the bottom portion of a V-shaped storage bin) to deposit the granulated waste onto the back of polyester carpeting resulted in plugging up of the depressions in the gravure roll in a very short time and made it virtually impossible to apply the granulated waste as a backcoating onto a suitable carpeting substrate.
Size reduction of waste by flock cutting: In yet another attempt to modify the carpeting waste to enable application and fusion to form a carpet backcoating, the waste was passed through a flock cutter to reduce it to the smallest possible particle size.
Since there is increasing use of polypropylene carpeting containing polyethylene fiber as a binder instead of cross-linked polyvinyl acetate, it was decided to granulate and flock cut the former waste in a manner similar to that containing crosslinked polyvinyl acetate and compare the two in a backcoating application.
Melting and fusing trials using flock cut waste: This waste was hand-applied to the back of polyester carpeting and treated similarly to the flock cut waste containing crosslinked latex.