Amorphous fluoropolymer manufactured articles

• US 6,469,116 B2
• Filed: 06/28/1999
• Issued: 10/22/2002
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: Ausimont, S.p.A.
• Original Assignee: Ausimont, S.p.A.
• Inventors: Drioli, Enrico, Grippaldi, Giuseppina, Arcella, Vincenzo, Maccone, Patrizia
• Primary Examiner(s): Zitomer, Fred
• Application Number:
  US09/340,137
• Publication Number:
  US 20020065383A1
• Time in Patent Office: 1,212 Days
• Field of Search: 526/247, 526/250, 526/255, 526/253
• US Class Current: 526/247
• CPC Class Codes: B01D 71/44 Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups B01D71/26-B01D71/42
• CPC Class Codes: C08F 214/262 with fluorinated vinyl ethers
• CPC Class Codes: C08F 34/02 in a ring containing oxygen coumarone-indene polymers C08F244/00

Abstract

Amorphous fluoropolymer selfsupported manufactured articles obtained by casting from solution in a single step, characterized in that they are obtained by the polymerization of a structure (I), optionally and preferably with a monomer having a structure (II):

CF₂=CY₁Y₂  (II)

wherein: R_f is a C₁-C₅ perfluoroalkyl radical; X₁ and X₂ are selected from F and CF₃; Y₁ and Y₂ are selected from F, Cl, H, CF₃, OR_f; having refractive index lower than 1.35, transmittance higher than 90% in the radiation field 300-2,000 nm wave length, and thickness higher than 20-25 μm.

Claims

1. Autosupported manufactured articles from amorphous flouropolymers in the form of films or membranes, obtained by casting from solution in a single step, wherein said amorphous polymers have been obtained by the copolymerization of a structure (I), with a monomer having a structure (II):

2. Manufactured articles according to claim 1 wherein the dioxole having structure (I) is 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD);

and the compounds having structure (II) are selected from the group consisting of tetrafluoroethylene, (C₁-C₅) perfluoroalkylvinylethers, trifluoroethylelene, hexafluoropropene, chlorotrifluoroethylene, vinylidene fluoride.

3. Manufactured articles according to claim 1 wherein the membranes are thick, asymmetrical and composite semipermeable membranes in flat, tubular form or hollow fiber.

4. A process for preparing manufactured articles according to claim 1, comprising the preparation of the amorphous polymer solution in a solvent up to a viscosity such that the solution can be handled and subsequently spread by casting in a single step on a support of a definite configuration.

5. A process for the preparation of manufactured articles according to claim 4 wherein in order to obtain the manufactured articles under the form of small tubes or capillaries, the solution is let flow in tubular glass supports having a predefinite internal diameter;

when the fluid has wetted all the support internal surface, the solution feeding is stopped and so coated support is kept under filtered inert gas;

the glass support is then thermally treated to completely dry the polymer;

the support is completely dipped in water, mechanically the polymer is completely taken off from the glass.

6. A process for preparing manufactured articles according to claim 4 wherein in order to obtain the manufactured articles in the form of films, the amorphous polymer solution is spread with a stratifying knife having a definite thickness on a flat and smooth support;

subsequently it is thermally treated for the solvent removal.

7. A process for the preparation of manufactured articles according to claim 6 wherein the film is in the form of autosupported thick membrane, optionally used on supports for the obtainment of composite membranes.

8. A process for the preparation of manufactured articles according to claim 7 wherein the membrane is asymmetrical, obtained by the phase inversion method using as non-solvent the aliphatic hydrocarbon class having from 5 to 10 carbon atoms.

9. A process for the preparation of manufactured articles according to claim 4 wherein the support for the solution spreading by casting is selected among glass/quartz, polymethylmethacrylate, polycarbonate, polyurethane, polystyrene, ceramic and metal supports, thermoplastic fluoropolymers.

10. A process for the preparation of manufactured articles according to claim 9, wherein the support is polyurethane.

11. A process for the preparation of manufactured articles according to claim 4 wherein the solvent is selected from (per)fluoropolyethers, dihydroperfluoropolyethers, fluorinated and perfluorinated ethers, optionally containing one or more H atoms in the end groups, perfluoroalkanes.

12. A process for the preparation of manufactured articles according to claim 11, wherein the (per)fluoropolyethers contain the following units, statistically distributed along the chain, selected from:

(C₃F₆O), (C₂F₄O), (CFXO) wherein X is equal to F or CF₃, (CR₁R₂CF₂CF₂O) wherein R₁ equal to or different from R₂ is H, F, perfluoroalkyl C₁-C₃.

13. A process for the preparation of manufactured articles according to claim 12 wherein the (per)fluoropolyethers are selected from:

a) —

O(C₃F₆O)_m′

(CFXO)_n′

—

wherein the (C₃F₆O) and (CFXO) units are perfluorooxyalkylenic units statistically distributed along the chain;

m′ and

n′

are integers such as to give products having boiling point in the range 60°

-300°

C., and m′

/n′

is comprised between 5 and 40, when n′

is different from 0;

X is equal to F or CF₃;

n′

can also be 0;

b) —

O(C₂F₄O)_p′

(CFXO)_q′

—

(C₃F₆O)_t′

wherein p′

, q′ and

t′

are integers such as to give products having the boiling point indicated in a), p′

/q′

is in the range 5-0.3, t′

can be equal to 0 and q′

/(q′

+p′

+t′

) lower than or equal to {fraction (1/10)} and the t′

/p′

ratio is from 0.2 to 6;

c) —

(CR₁R₂CF₂CF₂O)_n—

wherein R₁ and R₂ have the above indicated meaning, and n is an integer such as to give products with the boiling point indicated in a);

the end groups are selected from —

CF₃, —

C₂F₅, C₃F₇, optionally containing one or two chlorine atoms, and CF₂H, —

CFHCF₃.

14. A process for the preparation of manufactured articles according to claim 4, wherein a plasticizer is used having an average molecular weight higher than 1,000.

15. A process for the preparation of manufactured articles according to claim 4, wherein the amorphous polymer solution to be used for the casting is purified by filtering and/or centrifugation methods.

16. A process for the preparation of manufactured articles according to claim 15, wherein the solution is submitted to microfiltering and ultrafiltering/nanofiltering processes.

17. The process of claim 5, wherein the filtered inert gas is air.

18. The process of claim 5, wherein the filtered inert gas is nitrogen.

19. The process of claim 8, wherein the non-solvent used is the aliphatic hydrocarbon class which has 5 to 7 carbon atoms.

20. The process of claim 8, wherein the non-solvent used is n-pentane.

21. The process of claim 9, wherein the support is glass.

22. The process of claim 9, wherein the support is polyurethane.

23. The process of claim 13, wherein p′

/q′

is in the range of 2.7-0.5.

24. The process of claim 14, wherein the plasticizer has an average molecular weight higher than 3,000.

25. The process of claim 14, wherein the plasticizer has an average molecular weight higher than 8,000.

26. The process of claim 13, wherein m′

and n′

are integers such as to give products having a boiling point in the range of 60°

-150°

C.