| 摘要 |
<p>A seal for a valve for use in a pharmaceutical dispensing device, which seal is formed from an elastomeric composition comprising one or more elastomers and a cross-linking agent comprising an aliphatic dialkyl peroxide and/or an aliphatic perketal peroxide. Preferably, the cross-linking agent is of the formula I or II wherein R1-R6are each independently H, a saturated or unsaturated C1to C6alkyl; and wherein R7is a saturated or unsaturated C1-C18alkyl, a C1-C18alkyl valerate or a cyclic alkyl. The cross-linking agent may be a symmetric peroxide, preferably selected from one or more of: 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexene-3, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, n-butyl-4,4' -di(tel-t-butylperoxy)valerate and 1,1 ' -di (tert-butylperoxy)-3,3,5-trimethylcyclohexane. The elastomeric composition may also comprise a coagent or a crosslink activator. The seal is particularly suitable for use in pharmaceutical dispensing devices such as pressurised metered dose aerosol inhaler devices. A valve comprising the seal, a pharmaceutical device comprising the valve and a process for the preparation of the seal are also claimed.</p> |
