The invention relates to a contact adhesive based on a polyurethane of at least one diisocyanate and at least one low molecular weight polyethylene glycol, the polyethylene glycol having a molecular weight of up to 2,000 and the polyurethane having a degrees of crystallization of less than 20%. The contact adhesive can be applied from the melt or from an aqueous solution or dispersion. Surprisingly, it is suitable not only for polar plastic surface, but above all for PE and PP surfaces and of course for paper. Accordingly, the contact adhesive is preferably useful for applying paper labels to PE bottles.