PROCESS FOR OBTAINING THIN FILMS AND FILM-FORMING ARTICLES
Provided is a process for obtaining a film or film-forming article. The process includes a) providing a solvent system comprising at least one molecule bearing a sulfoxide function, where the solvent system has a water content of less than 1000 ppm by weight and having a pH of greater than or equal to 6. The process also includes b) preparing a polymer solution, either by dissolving the polymers in the solvent system or by synthesizing the polymers in the solvent system. The process also includes c) removing the solvent system to obtain the film or the film-forming article.
1 . A process for obtaining a film or film-forming article, said process comprising:
a) providing a solvent system comprising at least one molecule bearing a sulfoxide function, said solvent system having a water content less than 1000 ppm by weight and having a pH of greater than or equal to 6;
b) preparing a polymer solution, either by dissolving the polymers in said solvent system or by synthesizing the polymers in said solvent system;
c) removing the solvent system to obtain the film or the film-forming article.
2 . The process as claimed in claim 1 , wherein the water content of the solvent system is less than or equal to 900 ppm by weight.
3 . The process as claimed in claim 1 , wherein the solvent system has a pH ranging from 6 to 14.
4 . The process as claimed in claim 1 , wherein the solvent system comprises from 5% to 100% by weight of molecules bearing at least one sulfoxide function, relative to the total weight of the solvent system.
5 . The process as claimed in claim 1 , wherein the molecules bearing at least one sulfoxide function correspond to formula (1):
in which:
X and V, which may be identical or different, are chosen, independently of each other, from oxygen, sulfur, SO, SO 2 , NH and NR″;
a and b, which may be identical or different represent, independently of each other 0 or 1; n is equal to 1 or 2;
R, R′ and R″, which may be identical or different, are chosen, independently of each other, from a linear or branched alkyl radical, containing from 1 to 12 carbon atoms, a linear or branched alkenyl radical, containing from 2 to 12 carbon atoms, and an aryl radical containing from 6 to 10 carbon atoms; R, R′ and R″ possibly being substituted with radicals chosen from alkyl, alkenyl, aryl and halogen, and possibly containing one or more heteroatoms chosen from O, S, N, P and Si; R and R′ also possibly forming, together with the atoms that bear them, a hydrocarbon-based cyclic structure optionally containing one or more heteroatoms chosen from O, S and N, said cyclic structure including in total 5, 6, 7, 8 or 9 ring members.
6 . The process as claimed in claim 1 , wherein the molecules bearing at least one sulfoxide function correspond to formula (1a):
in which:
R and R′, which may be identical or different, are chosen from a linear or branched alkyl radical containing from 1 to 4 carbon atoms, a linear or branched alkenyl radical containing from 1 to 4 carbon atoms, and a phenyl radical; and
n is equal to 1 or 2.
7 . The process as claimed in claim 1 , in which the molecules bearing at least one sulfoxide function are dimethyl sulfoxide molecules.
8 . The process as claimed in claim 1 , wherein the polymer solution comprises from 1 to 90% by weight relative to the total weight of the polymer solution.
9 . The process as claimed in claim 1 , wherein the polymers are chosen from polyurethanes, polysulfones, polyvinylidene fluorides, polyether sulfones, polyphenyl sulfones, cellulose acetate, polyamides, polyacrylics, poly-epoxies, polymethacrylates, polycarbonates, silicones, vinyl polymers, polyimide-imides and polyimides.
10 . The process as claimed in claim 1 , wherein the polymer solution is obtained by dissolving the polymers in the solvent system at a temperature ranging from 10° C. to 120° C.
11 . The process as claimed in claim 1 , wherein the removal of the solvent system is performed by coagulating the polymers in a medium that is nonsolvent for said polymers and solvent for said solvent system.
12 . The process as claimed in claim 11 , wherein the medium that is nonsolvent for the polymers and solvent for the solvent system comprises at least 20% by weight of water, relative to the total weight of the medium that is nonsolvent for the polymers and solvent for the solvent system.
13 . The process as claimed in claim 1 , further comprising a step d) of treating the solvent effluents obtained on conclusion of step c).
14 . The process as claimed in claim 13 , wherein the treatment step d) comprises a preliminary step d1) of separation for recovering the molecules bearing at least one sulfoxide function, on the one hand, and the aqueous effluents, on the other hand.
15 . The process as claimed in claim 13 , wherein the treatment step d) comprises a chemical, biological and/or thermal oxidation, which is performed either directly on the solvent effluents derived from step c) or on the aqueous effluent derived from the preliminary step d1).
16 . The process as claimed in claim 13 , wherein the treatment step d) is performed at the site of implementation of steps a) to c) of the process as claimed in claim 1 .
17 . The process as claimed in claim 13 , wherein the treatment step d) is performed at a site different from the site of implementation of steps a) to c) of the process as claimed in claim 1 .