CR-4-USP ZINC OXIDE CAS# 1314-13-2

CR-4-USP Zinc Oxide is used in natural and synthetic rubber compounds as part of the cure system activation. It can also enhance heat aging properties of the vulcanized rubber. It is typically added a 3.0 – 5.0 phr level, early in the mixing process except with polychloroprene compounds. The high purity of CR-4-USP allows it to be used in medical and pharmaceutical rubber products.

Packaging: 50 lb. bags

Shelf life: 24 months from manufacturing date


*Zinc Oxide

99.9% Min.


20 ppm Max.


10 ppm Max.


10 ppm Max.


6 ppm Max.

*Loss at 110°C

0.07% Max.

*Loss on Ignition

0.20% Max.

*Retained on 325 mesh U. S. sieve

0.02% Max.

*Surface Area

4.0 - 5.0 m2/g

*Iron & other heavy metals

Pass USP tests


Pass USP tests


Pass USP tests

Bulk Density

35.0 – 45.0 lb/ft2

Specific Gravity, typical


*Actual tech data / technical data values reported on Certificate of Analysis

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      • Western Reserve Chemicals
      • 60 S. Seiberling Street
      • Akron, OH 44305

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