3M Dual Lock SJ3550 Type 250 Reclosable Fastener Black Acrylic Adhesive

3M SJ3550 Dual Lock Fastener

The 3M SJ3550 Dual Lock is a reclosable fastener with 250 stems per square inch for general-purpose attachment. It uses mushroom-shaped stems on a polypropylene carrier coated with an acrylic pressure-sensitive adhesive. The fastener bonds to metals, glass, and medium-to-high surface energy plastics and paint. It replaces screws, rivets, or hook-and-loop in applications needing access or repositioning.

Thermals Noise Power

This adhesive fastener has no moving parts, electronics, or power requirements, so it produces no heat, noise, or electrical draw. Performance depends on surface preparation and the combined stem density of the mating pairs. The acrylic adhesive provides a permanent bond to the substrate while the stems handle repeated closure cycles mechanically.

Type 250 Stem Density Mating

Type 250 fasteners mate with Type 170, 250, or 400 counterparts, with higher combined numbers yielding greater closure strength. The stems deliver five times the closure strength of standard hook-and-loop and a closure life of 1000 cycles. Engaged thickness measures 230 mils, while carrier and adhesive thickness totals 140 mils with a 4-mil liner.