Waterborne polyurethane adhesive composition and method for bonding articles

摘要

The present invention relates to novel waterborne adhesives which are polymerizable by UV light and are capable of being activated by heat, and which particularly display good adhesion to difficult substrates, such as ethylene vinyl acetate copolymers (EVA) with a low vinyl acetate content, or rubber. The invention further provides a novel method in which, after the application of the waterborne adhesive to an article and drying, irradiation with UV light and at the same time or thereafter activation by heat are performed. The adhesive film which is irradiated and activated in this way is then bonded to a further article. The invention also provides the use of the adhesives to make items such as shoes.

主权项

1. A method for bonding articles, comprising
I) coating an article with a waterborne dispersion comprising from 30.0 to 94.9 weight % of a polymer selected from the group consisting of crystalline or partly crystalline polyurethane, polyurea, and polyurethane polyurea, from 5.0 to 60.0 weight % of a monomer which can polymerise by radical polymerisation, from 0.1 to 10.0 weight % of a photoinitiator, and optionally, from 0.5 to 15.0 weight % of a crosslinking agent, wherein the weight percent relating to the solids content of said waterborne dispersion adds up to 100, and wherein, when measured by DSC to DIN 65467 at a heating rate of 20K/min, the polymer has a melting peak corresponding to an enthalpy of fusion of >3 J/g; II) removing water; III) irradiating with actinic radiation to form an irradiated film; IV) simultaneously with or after III), introducing heat into the irradiated film; and V) bringing the article into contact with a further article wherein the further article is coated with the waterborne dispersion of step I) or with another adhesive which is activated by heat.