Non-slip finishes are easy to understand. Their practical importance is much greater than one might suppose from first looking at these few pages. Since the main effect of non-slip finishes is to increase the adhesion between fibres and yarns regardless of fabric construction, the generic term for these finishes would be fibre and yarn bonding finishes. Other terms that can be used include anti-slip, non-shift and slip-proofing finishes.
Adhesion between yarns is especially important in woven fabrics at the seams and in highly stretched areas like the elbows of shirts, blouses and jackets. Slippage of warp and fill yarns can also be a problem during preparation, dyeing, printing and finishing. This shifting generates an unequal appearance of woven fabrics, but the yarns are not damaged as in similar knitwear defects. Fabric elongation, moir and crack marks can be caused by a too low yarn density, under-constructed fabrics and by very smooth fibres.
Smooth fibres, such as filaments of synthetic yarn, can cause similar problems in knitted fabrics. Runs, dropped stitches and snags are fabric defects that can be attributed to lack of fibre adhesion. Common terms for these interrelated problems are picking and snagging. The chemical products that reduce or eliminate these defects (anti-picking and anti-snagging finishes) are quite similar to non-slip finishes. Among the factors that can affect yarn slippage are fibre type, yarn size, fabric weave, yarn count (ends and picks per square inch or centimeter), fabric weight and type of finishing process.
Non-slip finishes are often used with under-constructed fabrics to compensate for the reduced yarn count and to achieve acceptable physical properties. Lining and pocketing fabrics made with smooth synthetic filaments are finished with friction enhancers combined with durable press agents, water repellents or hand modifiers to prevent seam slippage. Umbrella fabrics made from nylon or polyester filament yarns are treated with friction enhancers and water repellents. The properties of any woven fabric with long floats can usually be improved with nonslip finishes. In particular, Jacquard upholstery fabrics with long floats are stabilised by back coating with film-forming polymers. A special variation of the non-slip finishes, often combined with the incorporation of metal filaments, is the stab- and stitch-resistant finish, used for protective clothing and furniture, for example in trains and buses.