METHOD FOR PRODUCING A TYRE COMPRISING AN IMPROVED TREAD WITH A FOAMED MATERIAL

摘要

The invention relates to a method for producing a tyre comprising a tread. A layer of foamed material forms a rolling layer (14A) of a tread (14) incorporating tread pattern elements (20, 22, 26). In order to form the foamed material, a blank is provided with a mass of material comprising p,p'-oxybis (benzene sulfonyl) hydrazide forming a pore-forming agent. The blank is placed in a vulcanisation mould (28) comprising moulding elements (30, 32, 34). At least 95% of the moulding elements (30, 32, 34) each meet the following two conditions: a) the moulding element (30, 32, 34) is separated from at least one other moulding element (30, 32, 34) by a distance, expressed in millimeters, that is shorter than or equal to DM = 6.85 + 0.0065 T3, wherein T, which is higher than or equal to 3 pce, is the rate of p,p'-oxybis (benzene sulfonyl) hydrazide in the mass of material used to form the foamed material, and b) the moulding element (30, 32, 34) is used to form a tread pattern element (20, 22, 26) having a depth at least equal to 80 % of the thickness of the rolling layer (14A).