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Technical Data Sheet
Crystex™ CURE PRO

Chemical Synonym
  • Insoluble Sulfur, Polymeric sulfur
  • Rubber modification
  • Tires
  • Tires-custom

Product Description
CAS No. Polymeric sulfur: 9035-99-8 Process oil: 64742-52-5

Crystex™ Cure Pro is a non-blooming vulcanizing agent for unsaturated elastomers that offers tire manufactures improved productivity and reliability of supply without compromising safety. Crystex Cure Pro offers an unmatched combination of premium thermal stability, in-rubber dispersion and flowability. Crystex Cure Pro is oiled to 10.5 % but maintains the high standard of dust safety exhibited by existing Crystex products.


Crystex Cure Pro is polymeric sulfur and is insoluble in elastomers. Consequently, it will retard bin scorch, prevent migration of sulfur and preserve surface tack.

Crystex Cure Pro is used in compounds containing a relatively large sulfur loading above the solubility of sulfur in the elastomer and compounds that require higher processing temperatures or additional bloom protection.

Crystex Cure Pro offers less hassle during material handling, less tendency for product to compact, and improved accuracy in automatic dosing systems due to its significantly improved flow characteristics.

At vulcanization temperatures Crystex Cure Pro will de-polymerize to soluble sulfur and will behave similarly to Rubber Maker's sulfur.

Reversion of Crystex Cure Pro to soluble sulfur is also catalyzed by alkaline products. The presence of alkaline accelerators can be critical.

Crystex Cure Pro is non-staining and non-discoloring.

Typical Properties

PropertyTest MethodTypical Value, Units
Specific Gravity @ 20°CFDe18.21.8 approximate
Bulk DensityFDe18.1500-600 kg/m3
Bulk Density (compacted)FDe18.1700-800 kg/m3
Average particle sizeFPa17.1<70µm

Storage and Shelf Life
Crystex Cure Pro is a metastable product which can revert to soluble sulfur if not stored under proper conditions. Store Crystex Cure Pro in a well-ventilated area below 30 °C, avoiding exposure of the packaged product to direct sunlight. Do not store near products that can emit free amines such as sulfenamides and DTDM. Amines and other alkaline vapors can cause Crystex Cure Pro to revert to "Rubber Maker''s" sulfur at any temperature. High temperatures will also cause Crystex Cure Pro to revert to "Rubber Maker''s" sulfur. When stored in closed containers below 20 °C the reversion rate is less than 1 %/year. Reversion of Crystex Cure Pro could result in sulfur bloom of uncured rubber.

The shelf life of Crystex Cure Pro is 12 months from the date of manufacture, based on the recommended handling and storage conditions. Once the material has surpassed shelf life, please contact us if you would like to receive our suggestions for material re-verification, based on key product characteristics.

Handling Precautions
For detailed information on toxicological properties and handling precautions please refer to the current Safety Data Sheet. This information sheet can be downloaded from our web site or requested from the nearest Eastman office and should be consulted before handling this product. Hazards, ingredients, first aid, firefighting method, accidental release measures, exposure, personal protection, storage / handling, physical and chemical properties are all on SDS.

Properties reported here are typical of average lots. Eastman makes no representation that the material in any particular shipment will conform exactly to the values given.

Eastman and its marketing affiliates shall not be responsible for the use of this information, or of any product, method, or apparatus mentioned, and you must make your own determination of its suitability and completeness for your own use, for the protection of the environment, and for the health and safety of your employees and purchasers of your products. No warranty is made of the merchantability of fitness of any product, and nothing herein waives any of the Seller's conditions of sale.

10/25/2021 5:32:13 PM