EP0648787A1
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EP
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Process for preparing tetrafluoroethylene copolymers with other perfluorinated monomers
Assignee: Syensqo Specialty Polymers Italy SpA
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Filing: 1994-10-07
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Granted: —
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Expires: 2014-10-07
Abstract
Abstract The invention relates to a process for obtaining copolymers of tetrafluoroethylene with one or more perfluorinated monomers having ethylenic unsaturation, said copolymers having only carboxylic or carboxylate groups as unstable end groups, by polymerization in aqueous emulsion in the presence of a dispersing agent. The process is characterized in that CHF₂-CH₃ is used as chain transfer agent, and an inorganic peroxidic compound is used as initiator. The carboxylic or carboxylate groups are successively transformed into stable groups of the -CF₂H type by known stabilizing treatments.
Inventors
- 👤 Pasqua Colaianna
- 👤 Julio A. Abusleme
- 👤 Natalino Del Fanti
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 19:36
CPC Classifications
C; C08; C08F; C08F214/00; C08F214/18; C08F214/26; C08F214/262; C08F14/00; C08F14/18; C08F14/26; C08F2/00; C08F2/12; C08F2/16; C08F2/22
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
81 words
Process for preparing tetrafluoroethylene copolymers with one or more perfluorinated monomers having ethylenic unsaturation, said copolymers having, as unstable end groups, only carboxylic groups or carboxylate groups, by polymerization in aqueous emulsion in the presence of dispersing agents, characterized in that asymmetric difluoroethane CHF₂-CH₃ is used as chain transfer agent, in an amount comprised between 0.55 and 30% by moles with respect to the mixture of tetrafluoroethylene with the other perfluorinated monomer or monomers, and an inorganic peroxidic compound as initiator.
Claim 2
Dependent Claim
34 words
Process according to claim 1, characterized in that the amount of CHF₂-CH₃ is comprised between 0.55 and 10% by moles with respect to the mixture of tetrafluoroethylene with the other perfluorinated monomer or monomers.
Claim 3
Dependent Claim
46 words
Process according to claims 1 or 2, characterized in that the polymerization is carried out in the presence of a base or of a basic salt in such an amount that, at the polymerization end, all the unstable groups are in the form of carboxylate groups.
Claim 4
Dependent Claim
23 words
Process according to one or more of the previous claims, characterized in that the basic salt is a sodium or potassium basic salt.
Claim 5
Dependent Claim
40 words
Process according to one or more of the previous claims, characterized in that the base or the basic salt are used in such an amount to maintain the pH at a value comprised between 7 and 10 during the polymerization.
Claim 6
Dependent Claim
42 words
Preocess according to claim 1 or 2, characterized in that the polymerization is carried out in the absence of a base or of a basic salt, obtaining at the polymerization end all the unstable end groups in the form of carboxylic groups.
Claim 7
Dependent Claim
22 words
Process according to one or more of the previous claims, characterized in that the inorganic peroxidic compound is sodium or potassium persulphate.
Claim 8
Dependent Claim
34 words
Process according to one or more of the previous claims, characterized in that the dispersing agent is selected from the group consisting of sodium or potassium salts of perfluoroalkylcarboxylic acids and of perfluoroalkoxyethereal acids.
Claim 9
Dependent Claim
41 words
Process according to one or more of the previous claims, characterized in that the polymerization is carried out in the presence of an aqueous emulsion or microemulsion of perfluoropolyethers having perfluoroalkyl end groups, using, as dispersing agent, a perfluorinated dispersing agent.
Claim 10
Dependent Claim
91 words
Process for obtaining tetrafluoroethylene copolymers with one or more perfluorinated monomers having ethylenic unsaturation, said copolymers being without unstable end groups and having stable -CF₂H end groups, characterized in that the aqueous dispersion of the copolymers having, as unstable end groups, only carboxylate groups, obtained according to the process described in one or more of the claims from 3 to 5 and from 7 to 9, is brought to a pH comprised between 7 and 8, and, subsequently, is submitted to a thermal treatment at a temperature from 180 to 300°C.
Claim 11
Dependent Claim
91 words
Process for obtaining tetrafluoroethylene copolymers with one or more perfluorinated monomers having ethylenic unsaturation, said copolymers being free from unstable end groups and having stable -CF₂H end groups characterized in that the aqueous dispersion of the copolymers having, as unstable end groups, only carboxylic groups, obtained according to the process described in claim 6, is treated with a base or a sodium or potassium basic salt until a pH comprised between 7 and 8 is reached and, subsequently, is submitted to a thermal treatment at a temperature from 180 to 300°C.
Claim 12
Dependent Claim
145 words
Process for obtaining tetraflauoroethylene copolymers with one or more perfluorinated monomers having ehylenic unsaturation, said copolymers being free from unstable end groups and having stable end groups -CONH₂ by polymerization in aqueous emulsion in the presence of dispersing agents, characterized in that the polymerization is carried out in the presence of: 1° CHF₂-CH₃ in an amount from 0.55 to 30% by moles with respect to the mixture of tetrafluoroethylene with the other perfluorinated monomer or monomers, as chain transfer agent; 2° an inorganic peroxidic compound; 3° a base or a basic salt such as and in such an amount to maintain the pH at values comprised between 7 and 9 during the polymerization; 4° an ammonia aqueous solution in excess compared with the stoichiometric amount necessary to change all the end groups -COO⁻ coming from the chain transfer and from the initiator into -CONH₂ groups.
Claim 13
Dependent Claim
34 words
Process according to claim 12, characterized in that the amount of CHF₂-CH₃ is comprised from 0.55 to 10% by moles with respect to the mixture of tetrafluoroethylene with the other fluorinated monomer or monomers.
Claim 14
Dependent Claim
47 words
Process according to claims 12 or 13, characterized in that ammonium persulphate is used as inorganic peroxidic compound; an ammonium basic salt is used as base or basic substance; and an ammonium salt of a perfluoroalkylcarboxylic acid or of a perfluoroalkoxyethereal acid is used as dispersing agent.
Claim 15
Dependent Claim
40 words
Process according to one or more of claims 12-14, characterized in that the polymerization is carried out in the presence of an aqueous emulsion or microemulsion of perfluoropolyethers having perfluoroalkyl end groups, using, as dispersing agent, a perfluorinated dispersing agent.
References Cited (Backward Citations)
EP0220910A2
Cited
EP0457255A2
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