Useful coatings for heat-shrink prods. - consists of suitable polymer which bonds to heat-shrink article and incorporates indicator to show when correct shrinkage temp. arises

摘要

A thermally sensitive surface coating for heat-shrink prods., partic. for thermoplastic heat-shrink sleeves for cables, indicates the optimal temp. for shrinking. The coating used is a polymer which bonds to the surface of the sleeve. It can be filled with glass fibres and/or insecticide. The exampale shown is a heat-shrink sleeve (1) with a polymer coating (2) in bands. The sleeve (1) is e.g. roughened or treated with flame or corona discharge to render it capable of adhering and a hot melt coating is applied (2) at right angles to the direction of shrinkage in the form of bands 2mm apart. The coating is e.g. polyamide 4.6 with a crystallisation m.pt. of 290 deg. C and is 5% filled with short glass fibres. An adhesive (4) is applied to the inner face of the sleeve (1) which is activated at 290 deg. C. The sleeve shrinks i.e. when the coating (2) begins to flow. ADVANTAGE - The coating not only shows when a partic. temp. is reached but also performs other useful functions such as resistance to rodents, insects or microbes.