Patent ID: 8715785

Claim:
A process for mass producing hollow glass articles which, when positioned beside one another with the same orientation in one and the same plane, are liable to come into mutual contact along a surface of revolution, the method comprising hot treating the hollow glass articles before entering an annealing lehr to apply a first coating comprising a metal oxide to the hollow glass articles, after the hollow glass articles have left the annealing lehr and before entering into an optical checking machine, coating the surface of revolution with a second layer comprising a polymer without any solid contact between the hollow glass articles, and rotating the hollow glass articles through another turn at least along an axis of said surface of revolution in the optical checking machine and simultaneously coating the surface of revolution with a third layer comprising a polymer that is different from the polymer comprised in the second layer at a temperature of 20° C. to 100° C., wherein the maximum thickness of the combined thickness of the second coating and the third coating of the surface of revolution is from 1.5 to 5 times higher than the combined thickness of the second coating and the third coating on a surface other than the surface of revolution, wherein the second layer and the third layer reduce the coefficient of friction between the hollow glass articles and are not visible to a naked eye, wherein the hollow glass articles are glass bottles, glass flasks, or glass pots, and wherein the surface of revolution represents at most 50% of the external surface of the hollow glass articles.