Sika Schweiz Ag

Shingo Tsuno

Peter W Merz

Ukiwo Obasi Onuoha

New primers for the improvement of the adhesion of cross-linking adhesive systems top polyolefinic thermoplastic materials such as e.g., polypropylene, polyethylene or EPDM are disclosed. Said primers, on the one hand are characterized by a simple method of production and good storage stability, on the other hand by good wetting and good homogeneous film forming characteristics, said film forming characteristics enabling a uniform thickness of the layer, leading to good adhesion qualities. Essential constituents of such primers are prepolymers based on hydrogenated polyisoprene diol.

Primer

New thixotropic agents for the use in cross-linking systems, in particular one-component adhesives and sealants, are described. The thixotropic agents have the advantage that on the one hand they cause only a minor or no increase in viscosity, and on the other hand they do not cause any blead out or migration, respectively. The thixotropic agents of the present invention are based on urea derivatives that usually are present in a concentration of 5 to 50 wt.-%, in particular of 15 to 30 wt.-%, in a preferably reactive carrier material. After the cross-linking of the system, the reactive carrier material is incorporated, preferably into the structure matrix, or interwoven with said structure matrix, respectively, such that it can not diffuse out of the cured material.

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Zurich, Switzerland

Shingo Tsuno