Surface prepn. of plastic profiles for use with hot-melt adhesive - by irradiating with pulsed short wavelength radiation, esp. 320-440 nm UV, to form surface micro-cavities to allow penetration of adhesive

摘要

A process for the surface prepn. of plastic profiles (I) in order to improve their adhesiveness when using hot-melt adhesives comprises irradiating the surface with a pulsed beam of radiation of very low wavelength (L), resulting in cleavage of the mol. structure at the surface without penetrating inside the substrate, and leaving microscopic cavitites into which the adhesive can penetrate. Pref. radiation is very low wavelength UV, esp. with L = 320-440 nm. The pref. substrate is a profile of rigid PVC, methacrylate, plastic or similar material; this is irradiated as above, covered with a layer of paper, wood, PVC or PVC/paper which is coated with hot-melt adhesive, and then passed over a suitable hot roller to bond the coating to the substrate. USE/ADVANTAGE - Used, e.g. for applying decorative coatings of paper, plastic, wood, etc. to plastic substrates such as walls, doors, ceilings, windows, furniture parts etc. The process provides the surface of the substrate (acrylic resin, polyamide, PE, PP, polyurethane, PVC etc.) with the necessary porosity to ensure adequate penetration of hot-melt adhesive, without adversely affecting the bulk properties of the substrate. The process ensures high bond strength using low-cost hot-melt adhesives which can be applied in the open air (contrast solvent-contg. polyurethane adhesives).