Solvay Solexis S.p.a.

Solvay Specialty Polymers Italy S.p.a.

Valeri Kapeliouchko

Marco Malvasi

Tiziana Poggio

Stefano Ferrero

Giuseppe Marchionni

Vito Tortelli

Vincenzo Arcella

Marco Apostolo

Ivan Diego Wlassics

Mario Visca

Alba Chittofrati

Riccardo Pieri

Liubov Chernysheva

Giuseppe Filardo

Evasio Deregibus

Aniello Gargiulo

Fabrizio Spada

Alberto Mirigliani

Alessandro Galia

Onofrio Scialdone

Omar Ligabue

The invention pertains to a process for manufacturing a (per)fluoropolymer, said process comprising polymerizing one or more fluorinated monomers in the presence of a multi-phase medium, said medium comprising:

Method for manufacturing fluoropolymers

The invention pertain to a process for purifying a fluoropolymer dispersion, said process comprising: Still an object of the invention is an aqueous fluoropolymer dispersion comprising less than 1 ppm of fluorinated surfactant.

Fluoropolymer dispersion purification

A method for making a fluoropolymer comprising an aqueous emulsion polymerization of one or more fluorinated monomers wherein the aqueous emulsion polymerization is carried out in the presence of at least one cyclic fluorocompound of the following formula (I): wherein X, X, X, equal to or different from each other are independently selected among H, F, and C(per)fluoroalkyl groups, optionally comprising one or more catenary or non-catenary oxygen atoms; L represents a bond or a divalent group; Ris a divalent fluorinated Cbridging group; Y is a hydrophilic function selected among anionic functionalities, cationic functionalities and non-ionic functionalities.

A fluoropolymer [polymer (F)], a polymerisation process for its manufacture, and a molding process using such fluoropolymer [polymer (F)]. The polymerisation process comprises polymerising at least one fluorinated monomer in a polymerization medium, in which the polymerization medium is mixed by means of a stirring system comprising at least two counter-rotating impellers. Surprisingly and advantageously, the polymerization occurs without fouling or deposit formation on the reactor walls, and moreover, occurs with improved homogeneity, without composition, pressure or temperature gradients, thus enabling obtaining homogeneous polymer composition with no risk of local overheating. A polymer (F) obtained from such process has improved morphology (percentage of organized structures, i.e. of particles of regular shape) and, hence, has good free flowing properties which make it suitable for being processed by compression molding with no need of intermediate milling or grinding process or other size reduction process.

Polymerisation process

Fine fluoropolymer powders substantially fluorinated surfactant free, in particular fluorinated ionic surfactants, preferably perfluorooctanoic acid or its salts, comprising an anionic polyelectrolyte.

Fine fluoropolymer powders

A process for preparing a fluoropolymer dispersion that is substantially anionic fluorinated surfactant free includes adding to a fluoropolymer dispersion a nonionic surfactant having a cloud point (CP) between 40 and 80&#xb0; C. in a concentration of 1.5% to 50% by weight of the fluoropolymer, heating the dispersion up to a temperature Tin a range of CP&#xb1;10&#xb0;C., decanting the dispersion in a reactor at Tuntil obtaining a lower aqueous phase containing a concentrated fluoropolymer dispersion and an upper aqueous phase substantially not containing the fluoropolymer dispersion, washing the decanted dispersion with a solution of water and nonionic surfactant having a concentration of the nonionic surfactant of 0.5% to 50% by weight of the fluoropolymer, removing the upper aqueous phase from the upper part of the reactor, and discharge and recovery of the fluoropolymer dispersion.

Process for preparing fluoropolymer dispersions

A process to substantially remove fluorinated anionic surfactants from fluoropolymer dispersions comprising the following steps:

A process for producing a polymer by polymerizing at least one fluorinated monomer in the presence of a radical initiator and a surfactant in a polymerization medium containing essentially only carbon dioxide. The surfactant is a functional (per)fluoropolyether having recurring units (R1) and at least one functional group containing a heteroatom other than fluorine, the recurring units containing at least one ether linkage in the main chain and at least one fluorine atom. Molded article containing the polymer obtained from the process.

Polymerization process

Dispersions of fluorinated polymers substantially free from fluorinated surfactants, having high stability to shear combined with high stability to segregation, said dispersions comprising one or more anionic surfactants having the following general formula (1):Y'-(P)-CH(Y)-(P)-Y&#x2033;&#x2003;&#x2003;(1)wherein:

TFE copolymers

A process for preparing fluoropolymer dispersions, substantially free from anionic fluorinated surfactants, and with a coagulum amount &#x3c;0.1% by weight, comprising: a) step a1) addition of: 

A process to substantially remove the fluorinated anionic surfactants from fluoropolymer dispersions comprising the following steps:

A process to substantially remove the fluorinated anionic surfactants comprising the following steps:

Fluoropolymer aqueous dispersions having particles with average diameters from 150 to 400 nm, comprising bifunctional fluorinated surfactants having formula:A-R&#x2014;B&#x2003;&#x2003;(I)wherein:

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Alessandria, Italy

Valeri Kapeliouchko