The European Patent Office (EPO) has rejected calls by WL Gore & Associates Gmbh, holder of the Gore-Tex trademark, to withdraw a leather waterproofing patent held by its rival Nextec Srl.

The patent relates to the lamination of breathable waterproof membranes onto leather and it is at the heart of Nextec's OutDry technology used to make waterproof and breathable footwear and gloves.

The membrane is bonded directly to the inner side of leather shoe uppers, glove shells and clothing to prevent water penetration and overcomes the traditional system of waterproof membranes combined with a lining.

The decision by the EPO in Munich puts an end to a filing launched in 2004 by WL Gore which argued the technology was covered by previous documents and was not patentable.

The EPO Board of Opposition has rejected this view and has provided better definition on the scope of the claims to include elastic membranes which are adaptable to the stretch of natural leather.

Nextec says the OutDry technology is now protected by several granted and pending patents in Europe, the US, China, Japan and other manufacturing countries.