RUBBER MIX Russian patent published in 1994 - IPC

FIELD: production of tires and industrial rubber articles. SUBSTANCE: the rubber mix comprises (parts): 100 chlorobutyl rubber; 2.5 3.5 stearic acid; 1.8-2.2 sulfur; 1.1-1.5 tetramethylthiurem disulfide; 40-60 industrial carbon having a specific geometric surface of 90-110 m²/h; 7-15 barium sulfide; 0.5-0.8 mercaptoimidazoline and 3-15 natural zeolite. The viscosity of the rubber mix at 120 C is 62-74 conventional units. The additional vulcanization time is 60-90 min. The properties of rubber it has a conventional tensile strength of 21.7-23.7, an elongation of 470-525%, a hardness of 58-63 Shore A units, a multiple stretch resistance of 1150-1370 thousand cycles. After ageing (at 125 C for 5 days): the rubber has a tensile strength of 83-91% of the original value, an elongation of 95-99% of the original value, a decomposition starting temperature of 287-303 C. A variation in the weight of the rubber when the latter is swollen (%): 0.4-2.0 in icy acetic acid (20 C, 10 days): 4.0-6.2 in 10% oxalic acid (100 C, 3) days; and 0.5-1.2 in concentrated hydrochloric acid (20 C, 60 days). EFFECT: improved properties of the rubber mix. 2 tbl