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US 7,923,518 B2Granted
Nitrile rubbers
AssigneeLANXESS Deutschland GmbH
InventorWerner Obrecht
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Abstract
The present application provides novel nitrile rubbers comprising repeating units of at least one α,β-unsaturated nitrile, at least one conjugated diene and optionally one or more further copolymerizable monomers which nitrile rubbers are distinguished by a specific calcium content as well as a specific chlorine content and dispose of specific thio end groups. Additionally, an improved polymerization and work-up process is provided to produce the aforementioned nitrile rubbers.
Claims36
A nitrile rubber which contains repeating units of at least one α,β-unsaturated nitrile and, at least one conjugated diene and
- (i) has a calcium content of 150 ppm to 1290 ppm, based on the nitrile rubber, and a chlorine content of at least 40 ppm, based on the nitrile rubber, and
- (ii) contains 2,2,4,6,6-pentamethylheptane-4-thio, 2,4,4,6,6-pentamethylheptane-2-thio, 2,3,4,6,6-pentamethylheptane-2-thio and 2,3,4,6,6-pentamethylheptane-3-thio end groups,
- wherein the nitrile rubber has a storage stability of not more than 3 Mooney units, said storage stability calculated by the formula (I),
- storage stability =MV2−MV1 (I)
- where MV1 is the Mooney viscosity of the nitrile rubber and MV2 is the Mooney viscosity of the same nitrile rubber after storage at 100 ° C. for 48 hours.
2 more elements
Dependencies are inferred from the claim text.