Stretch Additive

Stretch additive changes the elasticity of cured plastisol, letting a print elongate along with fabrics carrying 2% to 10% or more spandex without the ink film splitting. It's mixed in at ratios the manufacturer specs per garment stretch, and it typically trades a small amount of opacity and cure speed for that added give.

This matters most on performance tees, compression shirts, and ribbed-knit collars, where a standard plastisol print will crack the first time the fabric is pulled taut, a race bib number on a moisture-wicking singlet, a logo across a ribbed athletic waistband. We've seen unmodified prints on stretch fabric crack visibly the very first time an athlete raised their arms overhead.

Pros reach for stretch additive automatically on anything with spandex or a tight athletic cut, and they'll often recommend water-based or discharge ink instead when the stretch factor is extreme, since those systems flex more naturally than plastisol even with additive. Placement matters too, avoiding high-stretch zones like side seams reduces stress on the ink regardless of formulation.

Buyers sometimes assume any plastisol print will hold up fine on activewear; without stretch additive, standard plastisol on a high-spandex garment is one hard stretch away from a cracked logo.