Claims
- 1. A process of the production of separators for use in cells comprising
- irradiating a film of an organic polymer 150 .mu.m or less thick with ionizing radiation at a dose rate of 5.times.10.sup.4 -10.sup.7 rads/sec. to give a total dose of 1 Mrad or more,
- thereafter contacting the irradiated film with an aqueous solution of a terminally unsaturated monomer substantially free of oxygen and containing at least one chlorine-containing organic solvent selected from the group consisting of ethylene dichloride and carbon tetrachloride, at a temperature of 10.degree. C.-60.degree. C. to thereby bring about the graft copolymerization of said monomer onto said film and
- then treating the grafted film with an aqueous alkaline solution.
- 2. The process as defined in claim 1 wherein said organic polymer is one selected from polyolefin resins.
- 3. The process as defined in claim 2 wherein said polyolefin resin is polyethylene.
- 4. The process as defined in claim 1 wherein said terminally unsaturated monomer is at least one member selected from the group consisting of acrylic acid, methacrylic acid, styrene sulfonic acid, vinyl pyridine and vinyl sulfonic acid.
- 5. The process as defined in claim 1 wherein said aqueous solution comprises 10-60% by weight of a terminally unsaturated monomer, 0.01-2.5% by weight of Mohr's salt and 37.5-89.99% by weight of water.
- 6. The process as defined in claim 1 wherein said aqueous solution of an alkali is an aqueous 2-10% by weight solution of an alkali hydroxide.
- 7. The process as defined in claim 1 wherein said aqueous solution of a terminally unsaturated monomer contains 2-15% by weight of at least one member selected from the group consisting of methyl alcohol, ethyl alcohol and isopropyl alcohol.
- 8. The process as defined in claim 1 wherein the irradiation is carried out either in vacuum or in an inert gas.
- 9. The process as defined in claim 1 wherein the irradiation is carried out either in air or in an oxygen atmosphere.
- 10. The process as defined in claim 1 wherein said film is an unstretched film.
- 11. A process as defined in claim 1 further comprising subjecting said film to extraction with water after the graft polymerization and before treatment with aqueous alkaline solution, in order to remove unreacted monomer and homopolymer.
- 12. A process as defined in claim 7 wherein said treatment with alkali hydroxide is effected at room temperature to 90.degree. C. for 5-120 minutes.
- 13. A process as defined in claim 1 wherein the total dose of ionizing radiation is 2-30 Mrads.
- 14. A process as defined in claim 1 wherein the terminally unsaturated monomer comprises a mixture of acrylic acid and tetraethylene glycol dimethacrylate.
- 15. The process as defined in claim 1 wherein the oxygen content of said aqueous solution is 0.1 ppm or less.
- 16. The process as defined in claim 1 wherein said aqueous solution contains one inhibitor of homopolymerization selected from the group consisting of ferrous salt and cupric salt.
- 17. The process as defined in claim 12 wherein said inhibitor of homopolymerization is used within the range of 0.01-2.5% by weight based on the amount of the aqueous solution.
- 18. The process as defined in claim 1 wherein said aqueous solution contains chlorinated organic solvent.
- 19. The process as defined in claim 1 wherein said aqueous solution contains a hydrophilic multi-functional monomer.
- 20. The process as defined in claim 2 wherein said hydrophilic multi-functional monomer is selected from the group consisting of polyethylene glycol diacrylate and polyethylene glycol dimethacrylate having the general formula:
- CH.sub.2 .dbd.CHCOO(CH.sub.2 CH.sub.2 O).sub.n COCH.dbd.CH.sub.2 or
- CH.sub.2 .dbd.C(CH.sub.3)COO(CH.sub.2 CH.sub.2 O)nCOC(CH.sub.3).dbd.CH.sub.2
- respectively, wherein n is an integer of 4-14.
Priority Claims (4)
Number |
Date |
Country |
Kind |
54-11982 |
Feb 1979 |
JPX |
|
54-11984 |
Feb 1979 |
JPX |
|
54-11986 |
Feb 1979 |
JPX |
|
54-11988 |
Feb 1979 |
JPX |
|
BACKGROUND OF THE INVENTION
This is a continuation-in-part application of U.S. patent application Ser. No. 118,101 filed on Feb. 4, 1980 now abandoned.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
3088791 |
Cline et al. |
May 1963 |
|
3188165 |
Magat et al. |
Jun 1965 |
|
3322661 |
Yoshikawa et al. |
May 1967 |
|
3427206 |
Scardaville et al. |
Feb 1969 |
|
3955014 |
Mostev et al. |
May 1976 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
118101 |
Feb 1980 |
|