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US 2015/0091202 A1Published application
Free-flowing pressure sensitive adhesives
AssigneeHenkel AG & Co. Kgm
InventorsMilan Burgsmueller, David Duckworth, Gerald Petry, Gunther Kratz, Eckhard Puerkner
Life of this patent
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Abstract
The invention relates to hot melt adhesives which are pressure sensitive adhesives whereby the adhesive is provided in a granulated form and is free-flowing and does not block during storage. Such pellets can be used as feed for automated feeder devices for the supply hot melt application systems.
Claims11
A method for forming a plurality of hot melt pressure sensitive adhesive pellets comprising the steps of:
- (A) melting a core comprising (i) a polyester, polyacrylate, polyolefin, polyurethane, ethylene vinyl acetate polymers, styrene block copolymers or mixtures thererof, and (ii) a tackifier;
- and the pressure sensitive adhesive material has a tacky surface at 25° C.;
- (B) melting a polymeric film comprising (i) a thermoplastic polymer and (ii) less than 20 wt-% wax, based on the total weight of the polymeric film;
- (C) extruding the core at a temperature above or at the softening point of the core;
- and
- (D) simultaneously co-extruding the polymeric film to surround the core whereby the polymeric film completely surrounds the core.
3 more elements
A process for forming a hot melt pressure sensitive adhesive pellets comprising the steps of:
- (a) melting a core of a pressure sensitive adhesive material that comprises (i) a polyester, polyacrylate, polyolefin, polyurethane, ethylene vinyl acetate polymers, styrene block copolymers or mixtures thererof, and (ii) a tackifier;
- and the material has a softening point of 80 to 150° C. and has a tacky surface at 25° C.;
- (b) extruding the core at a temperature in the range of 100° C. to 150° C. to form an extruded core;
- (c) co-extruding a polymeric film to surround the extruded core to form an adhesive, wherein the film comprises (i) a thermoplastic polymer with a melting point of 90° C. to 120° C. and (ii) less than 20 wt-% wax, based on the total weight of the polymeric film;
- (d) cooling the adhesive;
- and
- (e) pinching the adhesive to a form a plurality of pellets at a temperature where the polymeric film is stretched and covers the surface of the core. wherein having the extruded core is completely surrounded by a continuous outer shell of a polymeric film.
4 more elements
Dependencies are inferred from the claim text.