mixes were then vulcanized to rubber sheets 100 u00d7 100 u00d7 2 mm in electric heated presses 300 bar at 150 u00b0 c to t 90 5 min of the rheometer curves the mechanical dynamic properties of the vulcanizates were tested under various conditions 1 when fresh 2 after seven days 39 hot air aging at 70 u00b0 c 3 after 14 days 39 hot air aging 4 after extraction with acid water at ph4 and 80 u00b0 c the results appear in table 3 the hot air aging of the test bodies is intended to simulate the normal aging process of rubber articles in a shorter time and is well known to the person skilled in the art for this purpose extraction in acid water at ph 4 in these tests is intended to simulate the effects of acid rainwater for example and to dissolve the aminic anti aging agents out of the test body under intensified conditions extraction was effected by immersing the sample bodies in temperature controlled 80 u00b0 c aqueous buffer solutions the extraction medium was renewed daily as a reference test bodies were also tested which contained no anti aging agent without aaa and those protected against the aging process by vulkanox u00ae 4020 6 ppd the prior art the mechanical dynamic properties e g modulus m tensile strength ts and elongation at break eb of the vulcanizates are given in tables 4 6 these tests showed that compounds a and b according to the present invention already have better elongation at break in the mechanical properties of the fresh un aged.