Chemical name: Mixture of polymeric sulfur and silica
Crystex™ OT 33 AS is a non-blooming vulcanizing agent for unsaturated elastomers.
MAJOR APPLICATIONS AND PROPERTIES:
Because insoluble sulfur is metastable temperatures should be kept as low as possible during mixing. Between 100°C and 130°C significant reversion can take place to soluble sulfur.
Dispersion of Crystex™ OT 33 AS in rubber is critical. Due to its small particle size and its tendency for electrostatic charge build-up agglomerates can be formed which can result in inhomogeneous vulcanizates. Sufficiently long mixing times should be applied preferably in a separate mixing step under well controlled conditions.
If dry pre-mixes are produced of Crystex™ OT 33 AS and other vulcanization chemicals, reversion can take place if it is in direct contact with alkaline components.