Seal for a dispensing apparatus
A seal for a valve for use in a pharmaceutical dispensing device, which seal is formed from a thermoplastic elastomer including a propylene component with isotactic crystallinity.
1. A valve seal for use in a pharmaceutical dispensing device, wherein the seal comprises a sealing member formed from a seal material comprising a thermoplastic elastomer comprising a copolymer or terpolymer of propylene and one or more alpha-olefins selected from one or more of ethylene, butene, hexene, octene, and decene, wherein the propylene component constitutes at least 80% of the thermoplastic elastomer and at least a portion of the propylene component has isotactic crystallinity.
2. A valve seal as claimed in claim 1 , wherein the propylene component has from 2 to 25% isotactic crystallinity.
3. A valve seal as claimed in claim 1 , wherein the thermoplastic elastomer has a molecular weight (Mw) of at least 100,000.
4. A valve seal as claimed in claim 1 , wherein the seal material comprises an additional thermoplastic component.
5. A valve seal as claimed in claim 4 , wherein the additional thermoplastic component comprises one or more polymers selected from styrene-ethylene-ethylene-propylene, styrene-ethylene-propylene, styrene-butadiene-styrene, polyether block polyamide, polyether-polyester, ethylene-diene, polydimethylsiloxane/urea copolymers, and cyclo-olefin copolymers.
6. A valve seal as claimed in claim 4 , wherein the one or more additional thermoplastic components is/are present in the seal material in an amount of from 1 to 40 wt. %.
7. A valve seal as claimed in claim 1 , wherein the seal material further comprises a mineral and/or inorganic filler.
8. A valve seal as claimed in claim 7 , wherein the filler is selected from one or more of clays, calcined clays, nano particle clays, talcs and amino-silane-coated clays.
9. A valve seal as claimed in claim 7 , wherein the filler is present in the seal material in an amount of from 1 to 40 wt. %.
10. A valve seal as claimed in claim 1 , wherein the seal material is essentially free of a cross-linking agent.
11. A valve seal as claimed in claim 1 , wherein the seal material is essentially free of a plasticizer.
12. A valve seal as claimed in claim 1 , wherein the seal material is essentially free of a processing aid.
13. A valve seal as claimed in claim 1 , wherein the seal material is essentially free of a compatiblising agent.
14. A valve for use in a pharmaceutical dispensing device having a seal, wherein the seal is formed from a material comprising a thermoplastic elastomer comprising a copolymer or terpolymer of propylene and one or more alpha-olefins selected from one or more of ethylene, butene, hexene, octene, and decene, wherein the propylene component constitutes at least 80% of the thermoplastic elastomer and at least a portion of the propylene component has isotactic crystallinity.
15. A pharmaceutical dispensing device having a valve, wherein the valve comprises a seal, wherein the seal is formed from a material comprising a thermoplastic elastomer comprising a copolymer or terpolymer of propylene and one or more alpha-olefins selected from one or more of ethylene, butene, hexene, octene, and decene, wherein the propylene component constitutes at least 80% of the thermoplastic elastomer and at least a portion of the propylene component has isotactic crystallinity.
16. A pharmaceutical dispensing device as claimed in claim 15 which is a pharmaceutical metered dose aerosol inhaler device.
17. A dispensing apparatus for dispensing pressurised fluid comprising a valve body defining a chamber, a valve member extending movably through the chamber and through at least one annular seal co-operating with the valve member and the body to regulate the discharge of fluid, wherein the at least one seal is formed from a material comprising a thermoplastic elastomer comprising a copolymer or terpolymer of propylene and one or more alpha-olefins selected from one or more of ethylene, butene, hexene, octene, and decene, wherein the propylene component constitutes at least 80% of the thermoplastic elastomer and at least a portion of the propylene component has isotactic crystallinity.
18. A dispensing apparatus comprising a pressurised dispensing container having a valve body provided with two annular valve seals through which a valve member is axially slidable, said seals being disposed at inlet and outlet apertures of a valve chamber so that the valve functions as a metering valve, wherein at least one of the annular valve seals is formed from a material comprising a thermoplastic elastomer comprising a copolymer or terpolymer of propylene and one or more alpha-olefins selected from one or more of ethylene, butene, hexene, octene, and decene, wherein the propylene component constitutes at least 80% of the thermoplastic elastomer and at least a portion of the propylene component has isotactic crystallinity.
19. A dispensing apparatus as claimed in claim 17 , comprising a pressurised dispensing container operatively connected to the valve body and containing the fluid to be dispensed and a hydrofluorocarbon propellant comprising propellant type 134a or 227.
20. A dispensing apparatus as claimed in claim 17 , wherein the fluid to be dispensed comprises a liquid or particulate product as a solution or suspension in a carrier liquid comprising alcohol.
21. A dispensing apparatus as claimed in claim 20 , wherein the alcohol comprises ethanol.
22. A valve seal as claimed in claim 2 , wherein the propylene component has from 5 to 15% isotactic crystallinity.
23. A valve seal as claimed in claim 6 , wherein the one or more additional thermoplastic components is/are present in the seal material in an amount of from 1 to 10 wt. %.
24. A valve seal as claimed in claim 9 , wherein the filler is present in the seal material in an amount of from 1 to 30 wt. %.