What is claimed is:
1. A process for the copolymerization of a tetrafluoroethylene copolymer of the dispersionfine powder type, said copolymer containing essentially from 99.4% by weight to 99.98% by weight tetrafluoroethylene monomer units and from 0.02% by weight to 0.6% by weight copolymerized perfluorobutylethylene comonomer units, comprising:
(a) copolymerizing said monomer and comonomer in a pressurized reactor, and
(b) initiating said copolymerization by adding potassium permanganate (KMnO4),
(c) carrying out the entire reaction in the absence of any ionic strength enhancer, and
(d) stopping the addition of (KMnO4)initiator at a point in the reaction no further than 80% of the reaction completion.
2. The process of claim 1 including adding the comonomer as a precharge in the copolymerization reaction.
3. The process of claim 1 including adding the comonomer incrementally and intermittently, from the beginning of the reaction through only a portion of the complete reaction.
4. The process of claim 1 including stopping the addition of KMnO4 initiator at a point in the reaction no further than 60% of the reaction completion.
5. The process of claim 1 including stopping the addition of KMnO4 initiator at a point in the reaction no further than 50% of the reaction completion.
6. The process of claim 1 for the copolymerization of a tetrafluoroethylene copolymer of the dispersionfine powder type, wherein:
said polymerized comonomer units are present in an amount from 0.02% by weight to 0.6% by weight, based upon total copolymer weight; and
said copolymer has a raw dispersion primary particle size (RDPS) in the range between 0.175 microns to and including 0.203 microns and has a standard specific gravity (SSG) of less than 2.143.
7. The process of claim 6 wherein said copolymer has a RDPS in the range between 0.175 microns to and including 0.203 microns and has a SSG of less than 2.140.
8. The process of claim 6 including adding the comonomer as a precharge in the copolymerization reaction.
9. The process of claim 6 including adding the comonomer incrementally and intermittently, from the beginning of the reaction through only a portion of the complete reaction.
10. The process of claim 6 including stopping the addition of KMnO4 initiator at a point in the reaction no further than 60% of the reaction completion.
11. The process of claim 6 including stopping the addition of KMnO4 initiator at a point in the reaction no further than 50% of the reaction completion.
12. A tetrafluoroethylene copolymer of the dispersionfine powder type, containing polymerized tetrafluoroethylene monomer units, and copolymerized perfluorobutylethylene comonomer units, wherein:
(a) said copolymerized comonomer units are present in an amount from 0.02% by weight to 0.6% by weight, based upon total copolymer weight; and
(b) said copolymer has a raw dispersion primary particle size (RDPS) in the range between 0.175 microns to and including 0.203 microns and has a standard specific gravity (SSG) of less than 2.143.
13. The copolymer of claim 12 wherein said comonomer units are present in an amount from 0.05% by weight to 0.5% by weight.
14. The copolymer of claim 12 wherein the RDPS is within the range between 0.178 microns and 0.200 microns and has a SSG of less than 2.140.
15. The copolymer of claim 12 dispersed within an aqueous dispersion.
16. The copolymer of claim 12 in the form of fine powder.
17. A tetrafluoroethylene copolymer of the dispersionfine powder type, containing polymerized tetrafluoroethylene monomer units and copolymerized perfluorobutylethylene comonomer units, wherein:
(a) said copolymerized comonomer units are present in an amount from 0.05% by weight to 0.5% by weight, based upon total copolymer weight; and
(b) said copolymer has a RDPS between 0.178 microns and 0.200 microns and has a SSG of less than 2.140.
18. The copolymer of claim 17 dispersed within an aqueous dispersion.
19. The copolymer of claim 17 in the form of fine powder.
20. The copolymer of claim 12 shaped into the form of expanded beading having a break strength of at least 7.9 lbs.
21. The copolymer of claim 17 shaped into the form of expanded beading having a break strength of at least 9.0 lbs.
22. The copolymer of claim 20 having a break strength of at least 11.0 lbs.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A dose form of sumatriptan comprising a condensation aerosol
formed by heating a thin layer containing sumatriptan, on a solid support, to produce a vapor of sumatriptan and condensing the vapor to form a condensation aerosol
characterized by less than 10% sumatriptan degradation products by weight, and
an MMAD of less than 5 microns, wherein the dose form comprises less than 20 mg of sumatriptan.
2. A dose form of frovatriptan comprising a condensation aerosol
formed by heating a thin layer containing frovatriptan, on a solid support, to produce a vapor of frovatriptan and condensing the vapor to form a condensation aerosol
characterized by less than 10% frovatriptan degradation products by weight, and
MMAD of less than 5 microns, wherein the dose form comprises less than 2 mg of frovatriptan.
3. A dose form of naratriptan comprising of a condensation aerosol
formed heating a thin layer containing naratriptan, on a solid support, to produce a vapor of naratriptan and condensing the vapor to form a condensation aerosol
characterized by less than 10% naratriptan degradation products by weight, and
an MMAD of less than 5 microns, wherein the dose form comprises less than 0.8 mg of naratriptan.
4. A method of producing a dose form of sumatriptan comprising a condensation aerosol, the method comprising:
a. heating a thin layer containing sumatriptan, on a solid support, to produce a vapor of sumatriptan, and
b. providing an air flow through the vapor to form a condensation aerosol characterized by less than 10% sumatriptan degradation products by weight, and an MMAD of less than 5 microns, wherein the dose form comprises less than 20 mg of sumatriptan.
5. A method of producing a dose form of frovatriptan comprising a condensation aerosol, the method comprising:
a. heating a thin layer containing frovatriptan, on a solid support, to produce a vapor of frovatriptan, and
b. providing an air flow through the vapor to form a condensation aerosol characterized by less than 10% frovatriptan degradation products by weight, and an MMAD of less than 5 microns, wherein the dose form comprises less than 2 mg of frovatriptan.
6. A method of producing a dose form of naratriptan comprising a condensation aerosol, the method form comprising:
a. heating a thin layer containing naratriptan on a solid support, to produce a vapor of naratriptan, and
b. providing an air flow through the vapor to form a condensation aerosol characterized by less than 10% naratriptan degradation products by weight, and an MMAD of less than 5 microns, wherein the dose form comprises less than 0.8 mg of naratriptan.