A component of tufted carpet consisting of woven or nonwoven fabric into which pile yarn tufts are inserted by the tufting needles. It is the carrier fabric for the pile yarn and should not be con- fused with secondary backing which is a reinforcing fabric laminated to the back of tufted carpet subsequent to the tufting process. Most primary backing is either woven or nonwoven polypropylene, although woven jute is still sometimes used. Some synthetic primary backings have nylon fibre attached to their upper surfaces to make them union dyeable with nylon pile yarns.
