Method for manufacturing fluoroelastomers in aqueous emulsion without using fluorinated surfactants
AssigneeSYENSQO SPECIALTY POLYMERS ITALY S.p.A.
InventorsFiorenza D'Aprile, Alessio Marrani
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Abstract
The present invention relates to a method for manufacturing fluoroelastomers via emulsion polymerization in the absence of fluorinated surfactants and in the presence of one or more polycarboxylic acid having from 2 to 22 carbon atoms. The invention also relates to an aqueous fluoroelastomer latex and to a fluoroelastomer which can be obtained from the process.
Claims15
A method of making a fluoroelastomer [fluoroelastomer A] in an aqueous reaction medium free from fluorinated surfactants said method comprising:
- a:
- forming an aqueous emulsion comprising:
- i) one or more polycarboxylic acid having from 2 to 22 carbon atoms, in acid or salt form,
- iii) a free-radical initiator,
- ii) monomers comprising vinylidene fluoride (VDF) and one or more fluorinated monomer different from VDF,
- iv) optionally a chain transfer agent;
- b:
- initiating the polymerization of said monomers, thereby forming a fluoroelastomer [fluoroelastomer A] as a stable latex,
- wherein:
- said fluoroelastomer A comprises 30-80% by moles of recurring units derived from vinylidene fluoride (VDF), and 20-70% by moles of recurring units derived from one or more fluorinated monomer different from VDF.
An aqueous latex, free from fluorinated surfactants, comprising one or more polycarboxylic acid having from 2 to 22 carbon atoms, in acid or salt form, and particles of a fluoroelastomer A, wherein said particles of fluoroelastomer A have an average particle size, measured according to ISO 13321, below 400 nm and wherein said fluoroelastomer A:
- comprises 30-80% by moles of recurring units derived from VDF, 20-70% by moles of recurring units derived from one or more fluorinated monomer different from VDF,
- possesses a Mooney viscosity (ML1+10 (121° C.)) of at least 10 MU, and
- comprises —CH2OH chain ends in an amount of zero to less than 10 mmol/kg of fluoroelastomer A.
A fluoroelastomer A possessing a Mooney viscosity (ML1+10 (121° C.)) of at least 10 MU;
- and comprising:
- 30-80% by moles of recurring units derived from VDF, 20-70% by moles of recurring units derived from one or more fluorinated monomer different from VDF,
- CH2OH chain ends in an amount of zero to less than 10 mmol/kg of fluoroelastomer A, and
- hydrogen-comprising chain ends selected from the group consisting of —CF2H and —CF2CH3 in an amount of 15 to 100 mmol/kg of fluoroelastomer A.
Dependencies are inferred from the claim text.