Elastomeric composition for pharmaceutical articles
Elastomeric polymers and compounded elastomers have reduced amounts of leachables. The compound comprises a polymer and 50 to 100 phr of filler. The polymer is prepared by reacting a mixture of i) a C 4 to C 7 isoolefin monomer, ii) a styrene based monomer, and optionally iii) a C 4 to C 14 multiolefin monomer wherein the polymer contains 5 to 15 wt % of styrene derived units. At least 5% of the filler is precipitated silica.
1. An elastomeric composition, the composition comprising:
a halogenated polymer, the halogenated polymer consisting of i) C4 to C7 isoolefin monomer derived units, ii) non-functionalized alkylstyrene derived units, and iii) halogen functionalized alkylstyrene derived units, wherein the halogenated polymer contains 5 to 15 wt % of alkylstyrene derived units,
a cure package, and
50 to 100 phr of filler,
the composition being characterized by 10 to 60% of the total filler, based on the total phr of the filler in the composition, is precipitated silica and the remaining amount of filler is calcined clay and the cure package is present in amounts of 0.1 to 5 phr.
2. The elastomeric composition of claim 1 , wherein the precipitated silica comprises silanol groups.
3. The elastomeric composition of claim 1 , wherein the cure package comprises a carbamate or a metal oxide.
4. The elastomeric composition of claim 1 , wherein the cure package comprises a carbamate, the carbamate being present in amounts of not more than 2.0 phr.
5. The elastomeric composition of claim 1 , wherein the elastomeric composition further comprises a plasticizer.
6. The elastomeric composition of claim 1 , wherein the polymer is halogenated with either bromine or chlorine.
7. The elastomeric composition of claim 1 , wherein the alkylstyrene derived units are present in the halogenated polymer in an amount of 7.5 to 10 wt %.
8. The elastomeric composition of claim 1 , wherein the isoolefin is selected from the group consisting of isobutylene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-butene, 2-butene, hexene, and 4-methyl-1-pentene.
9. An article formed of the composition of claim 1 .
10. The article of claim 9 , wherein the article is a vial stopper or a vial seal.