Abstract:
The invention relates to granules comprising zinc oxide and precipitated silicic acid which are readily dispersible in rubber blends, to a process for their production, and to their use.
Abstract:
Mouldable and vulcanisable rubber mixtures are made containing a rubber (A) which still contains double bonds and which is cross-linkable by means of sulphur and a vulcanization accelerator or a mixture of rubber (A) with a different rubber (B), 0.2 to 10 parts of sulphur, 0.2 to 10 parts of a vulcanization accelerator and 1.0 to 10 parts of a bis-(alkoxysilylalkyl)polysulfide. There can also be present a silicate filler and/or a carbon black filler of rubber. The rubber mixtures have the silane, vulcanization accelerator and sulphur, calculated as S8 present in a molar ratio which causes the rubber mixture to have a reversion R=O (+/-5%) resulting from the cross-linking isotherm at the vulcanization temperature where the reversion R is calculated according to Formula II in which Dmax is the maximum vulcameter moment of rotation Dmin is the minimum vulcameter moment of rotation D(max+60 min) is the vulcameter moment of rotation measured 60 minutes after the appearance of the maximum moment of rotation. There is also disclosed the process of vulcanizing the above-mentioned rubber mixtures or moulding compositions and forming vehicle tires using the rubber mixtures.
Abstract:
A method of granulating resorcinol/silica mixtures which comprises transporting a mixture of resorcinol and precipitated silica by conveyor worms to two pressing rollers whose shafts are attached vertically above one another and whose contact pressure can be varied, compacting said mixture between said rollers, breaking up the compacted mixture with a cake breaker to obtain a granulate with minimum grain size and separating the remaining dusty portion of said mixture. The mixtures can be added to vulcanizable rubber to provide improved adhesion to rubber reinforcements.