JPS623161B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a fluorine-containing polymer having a _-CF2I group and/or a >CFI group as a functional group. Fluorine-containing polymers having chemically bonded iodine atoms in their molecules (hereinafter simply referred to as fluorine-containing polymers having iodine) can be used in various ways by utilizing the reactivity of the iodine atoms. For example, ~ _CF2I groups in a fluorine-containing polymer membrane are reacted with a Grignard reagent such as _C6H5MgBr to form _{~ CF2MgBr} groups, and then reacted with sulfonyl chloride to form _{~ CF2SO2Cl} , A method of converting into a sulfonic acid group by hydrolysis has been proposed. Furthermore, a perfluoropolymer containing ~ _CF2I groups is reacted with tetraethylpyrophosphite in the presence of a radical initiator, followed by oxidation,
By hydrolysis, phosphonic acid group

It has been proposed that it is possible to obtain polymers having the group [Formula]. Furthermore, JP-A-53-
Publication No. 86788 describes an example of radical crosslinking of an iodine-containing fluorine-based polymer. In order to provide a smooth and advantageous means for producing fluorine-containing polymers containing iodine, the present inventor has conducted various studies and examinations, and as a result of conducting various studies and examinations, the present inventors have discovered that iodine, etc. can be reacted with fluorine-containing polymers having specific carboxylic acid groups. By letting
It has been found that the above objects can be advantageously achieved.
That is, by swollen a fluorine-containing polymer having -CF ₂ CO ₂ H groups, etc., preferably in a solvent and reacting it with iodine or the like in the presence of a radical initiator such as peroxide, -CF ₂ Fluorine-containing polymers having I groups etc. can be obtained smoothly and advantageously. Thus, the present invention provides that as a functional group -
A first fluorine-containing polymer having a CF ₂ CO ₂ H group and/or a >CFCO ₂ H group is reacted with an iodine and/or an iodine-containing compound to form a -CF ₂ I group and/or a >CFI group.
The present invention provides a novel method for producing a fluorine-containing polymer having iodine, which is characterized by producing a second fluorine-containing polymer having a group. The method of reacting the first fluorine-containing polymer with iodine or an iodine-containing compound is not particularly limited, and any known or well-known method may be employed as appropriate. for example,
The first fluorine-containing polymer and iodine or an iodine-containing compound are reacted in the presence of heat, light, ionizing radiation, a radical initiator, or other catalyst in the presence or absence of a suitable solvent. Good. Specifically, methods include methods of irradiating ultraviolet rays in the presence of vapor of elemental iodine, methods of heating, methods of irradiating with ionizing radiation; methods of heating in the presence of elemental iodine and a radical initiator; A method of dissolving in an organic solvent and heating it; a method of coexisting a photosensitizer and irradiating it with visible light and ultraviolet light; and a method of combining two or more methods, such as a method of heating in the presence of a radical initiator and simultaneously irradiating it with ultraviolet light. For example, a method of doing so may be exemplified. In the present invention, the reaction can be easily carried out by contacting with iodine vapor, but of course the reaction with iodine can also be carried out in the form of a solution. Furthermore, when using an iodine-containing compound, it is preferable to carry out the reaction in a solvent that can dissolve the iodine-containing compound. Generally, the reaction between the first fluorine-containing polymer and iodine or an iodine-containing compound can be carried out by selecting various reaction conditions or operations depending on the reaction method, the type of raw materials, etc. Generally, when only heat is used, it is carried out within a temperature range of 200° C. or higher, preferably 250° C. or higher, at which the first fluorine-containing polymer does not decompose. When using light, ultraviolet light is preferable, but it is not necessarily ultraviolet light, and visible light may be used in the presence of a sensitizer. As the photosensitizer in this case, conventionally known or well-known ones can be used without any restriction, and can be appropriately selected depending on the purpose. Ionizing radiation is α, β, γ, and This must be done within a range that does not result in a decrease in mechanical strength. Further, as the radical initiator in a preferred embodiment of the present invention, any conventionally known or well-known organic or inorganic type can be used without limitation, and examples of the organic type include hydrocarbon type, fluorine-containing type, and permeable type. Fluoro-based materials can be selected as appropriate, but those with a half-life of decomposition of 40° C. or higher and 10 hours or longer are selected. Specifically, benzoyl peroxide, p-nitrobenzoyl peroxide, m-chlorobenzoyl peroxide, tertiary butylperoxyisopropyl carbonate (BPIC), perfluorobenzoyl peroxide, and the like can be exemplified. In the present invention, iodine is preferably used, and the iodine may be in elemental, gaseous, solution, or solid form, and in the case of solution, the concentration is not particularly limited, but is usually 0.001% by weight. ~Used up to saturated solutions. The solvent used when the solution is in the form of a solution is selected in part for the purpose of dissolving iodine and controlling the degree of reaction to the first fluorine-containing polymer. For example, if only the vicinity of the surface layer of the first fluorine-containing polymer is to be reacted, a solvent having poor affinity for the first fluorine-containing polymer is used to react only the surface layer;
In addition, if the reaction is to proceed uniformly to the inside, it is desirable to use a solvent that has good affinity for the first fluorine-containing polymer and can sufficiently swell it. Further, as the iodine-containing compound, inorganic or organic iodine salts are used. The inorganic iodine salt is not particularly limited, and the cation may be an alkali metal salt, an alkaline earth metal salt, a transition metal iodine salt, or a complex salt. As organic iodine salts, organic compounds with so-called onium bases such as primary, secondary, and tertiary amines, quaternary ammonium bases, arsonium bases, phosphonium bases, and sulfonium bases combined with cations are used. The chain is not particularly limited, such as a saturated or unsaturated straight chain, a branched chain alkyl group, a cyclic chain, a chain having an aromatic ring, or a chain having a heterocycle. Furthermore, the iodine-containing compound is not in the form of a salt as described above, but may also be one in which iodine is bonded to a halogen compound such as bromine or chlorine through a covalent bond. In the present invention, it is important that the first fluorine-containing polymer has _{a -CF2CO2H} group and/or a > _CFCO2H group as a functional group. There is no particular reason to limit the content of the functional groups, and they may be bonded in a uniform or non-uniform distribution in the fluorine-containing polymer. The form of the first fluorine-containing polymer is not particularly limited and may be in the form of granules, powder, lumps, or molded products such as membranes or films. That is, the first fluorine-containing polymer may be formed into a film before the reaction of the present invention, or, of course, may be formed after being formed into the second fluorine-containing polymer. Furthermore, in the case of a film-like material, the functional groups may be unevenly distributed on one or both surface layers. The first fluorine-containing polymer may contain functional groups other than the above-mentioned specific functional groups. In addition, the first fluorine-containing polymer can be selected to have an appropriate amount of fluorine content depending on the purpose, but from the viewpoint of heat resistance, chemical resistance, acid resistance, oxidation resistance, etc., perfluorocarbon-based polymers are used. Preferably. Of course, depending on the intended use of the second fluorinated polymer, it may contain chlorine, bromine, hydrocarbon groups, etc. within a practical range. In addition, it is preferable that the specific functional group is bonded to the side chain of the polymer, but if the functional group is bonded to the end of the side chain that has a perfluorocarbon side chain formed on the perfluorocarbon main chain, suitable. Furthermore, the specific functional group may be bonded via an ether bond, a thioether bond, or a fluorine-containing alkylene group. Preferred specific examples of the first fluorine-containing polymer include the following. That is, (p is an integer of 0 to 5, q is an integer of 1 to 10) (the molar ratio of x/y is 5/95 to 30/70). In the present invention, a particularly preferred embodiment is to swell the first fluorine-containing polymer in a solvent and react it with iodine in the presence of peroxide.
As such a solvent, a fluorine-containing solvent such as 1,1,2-trifluoro-1,2,2-trichloroethane is suitable, and the amount of solvent per gram of the fluorine-containing polymer is
About 10 to 20 g can be adopted. A reaction temperature of 80 to 150°C, preferably about 100 to 130°C may be employed. There is no limit to the reaction time, usually 2 to 6
About an hour is enough. As peroxide,
Examples include benzoyl peroxide, tertiary butylpaoxyisopropyl carbonate (BPIC), and 0.1 to 1 mole of ~CF ₂ CO ₂ H or >CFCO ₂ H group in the first fluorinated polymer. About 3 moles,
Preferably, about 1.2 to 1.5 mol is employed. This reaction molar ratio can be changed as appropriate depending on the form of the desired product. In addition, iodine is 0.5 to 3 times the mole of peroxide used, preferably 1.2
It can be selected from a range of about 2.2 times the mole. The second fluorine-containing polymer having iodine obtained in the present invention can be employed for various purposes in various fields. For example, by introducing an ion exchange group such as a sulfonic acid group or a phosphonic acid group, it can be used as an ion exchange resin or an ion exchange membrane. Furthermore, by utilizing the radical crosslinking properties of iodine, it can be used as a crosslinking site in fluorine-based elastomers. Next, embodiments of the present invention will be described in more detail, but it goes without saying that the present invention is not limited by such explanations. Example 1 Tetrafluoroethylene and methyl-4-(1.
A copolymer (number average molecular weight of approximately 500,000) of 1,2-trifluorovinyloxy)-perfluorobutanoate (CF ₂ = CFO (CF ₂ ) ₃ CO ₂ CH ₃ ) is hydrolyzed to form a carboxylic acid type. It was converted to . The carboxylic acid type functional group capacity was 1.42 meq/gram dry resin.
70.4 g of this carboxylic acid type resin was added to 860 g of 1.1.2-trifluoro-1.
It was suspended in 2,2-trichloroethane (R-113) and heated to 100°C for 1 hour to completely swell. After cooling, 75.0 g (290 mmol) of iodine and 35.8 g
(148 mmol) of benzoyl peroxide was added and heated to 100℃ for 3 hours and 120℃ for 2 hours while stirring well.
Holds time. After cooling, the resin is filtered off and then R
-113/acetone/methanol mixed solvent and finally methanol. It was dried under reduced pressure at 80° C. for 16 hours to obtain 80 g of dry polymer. When taking an infrared absorption spectrum of this polymer, the absorption at 1780 cm ^-1 due to carboxylic acid groups disappeared, and at 760 cm ^-1 -
It showed absorption based on CF ₂ I group. As a result of elemental analysis, it was found that 1.25 milliequivalents of iodine was contained per gram of dry resin. From these results, it was found that conversion of carboxylic acid to iodide occurred almost quantitatively. Example 2 20 g of a carboxylic acid-type perfluoropolymer with an ion exchange capacity of 1.28 meq/g resin was added to 430 g of 1,2-difluoro-polymer in an autoclave.
It was suspended in 1,1,2,2-tetrachloroethane and heated to 100°C for 1 hour to completely swell.
After cooling, 21.3 g (84 mmol) of iodine and 70.4 g (40
mmol) of tertiary butyl peroxyisopropyl carbonate (BPIC) was added, and the mixture was kept at 120°C for 1 hour and at 135°C for 2 hours while stirring well. After cooling, the resin was filtered off, then washed with an acetone-methanol mixed solvent and finally with methanol.
It was dried under reduced pressure at 80° C. for 16 hours to obtain 23 g of dry polymer. 760 cm ^-1 in infrared absorption spectrum
It exhibited characteristic absorption based on CF ₂ I. As a result of elemental analysis, it was found that 1.08 milliequivalents of iodine was contained per gram of resin. Example 3 65 using azobisisobutyronitrile as an initiator
Tetrafluoroethylene and CF ₂ = CFO (CF ₂ ) ₃ COOCH ₃ and (Preparation ratio 80/20) was copolymerized in bulk system, and TQ was achieved with ion exchange capacity 1.37 meq/g polymer.
A copolymer at 210°C was obtained. The copolymer was press-molded at 210°C to obtain a film with a thickness of 300μ. After pasting the two films together and sealing the periphery with polytetrafluoroethylene packing,
It was immersed in a 25wt% caustic soda solution at 90°C for 1 hour, and then in concentrated hydrochloric acid at 90°C for 1 hour. Then, after thoroughly washing with water and drying, it was immersed in 1,2-difluoro-1,1,2,2-tetrachloroethane and heated at 90°C for 1 hour to cause the surface to swell well. After cooling, iodine and benzoyl peroxide were added, and the reaction system was kept at 100°C for 5 hours. After thoroughly washing the film with methanol and drying it, the infrared absorption spectrum of the film surface revealed that the carboxylic acid group was 760 cm ^-1.
It was found that it was converted to a CF ₂ I group. Application example 1 20 g of the perfluoropolymer having a pendant side chain containing -CF ₂ I groups obtained in Example 1 was suspended in 300 ml of 1,1,2-trichloro-1,2,2-trichloroethane, 21.7 g of tetraethyl pyrophosphite and 4.1 g of ditertiary butyl peroxide were added, and the mixture was heated and stirred in an autoclave at 100°C for 2 hours and at 120°C for 3 hours. The resulting polymer suspension was cooled to 0°C under a nitrogen stream,
It was oxidized with 50 ml of methanol solution containing 11.34 g of tertiary butyl hydroperoxide. The polymer was filtered off, washed with methanol, and then dried under reduced pressure. Next, this polymer was heated to reflux in 50 ml of 1N hydrochloric acid, and the polymer was filtered, washed, and dried to give a total of 19.8
g of dry polymer was obtained. Phosphonate groups by elemental analysis and titration

The content of formula was 0.81 meq/gram dry resin. The infrared absorption spectrum of this resin was 1280 ~
Strong absorption based on P=O and CF ₂ was observed at 1100 cm ^-1 . Application Example 2 The film obtained in Example 3 was immersed in a tetrahydrofuran solution of C ₆ H ₅ MgBr and left at -70°C for 5 hours and at -40°C for 2 hours. After cooling again to −70 °C, add excess SO ₂ Cl ₂ and cool to −70 °C for 24 h.
It was then brought back to room temperature. After taking out the membrane and washing it with dilute hydrochloric acid and then water, the bonded membrane was separated and 25wt
% caustic soda solution at 90°C for 16 hours. It was confirmed from the infrared absorption spectra of both surfaces of the film that the treated surface was _-SO3Na , and the other surface was -COONa.

Claims (1)

[Claims] 1. -CF ₂ CO ₂ H group and/or > as a functional group
A first fluorinated polymer having a CFCO ₂ H group is reacted with iodine and/or an iodine-containing compound.
1. A method for producing a fluorine-containing polymer having iodine, which comprises producing a second fluorine-containing polymer having a CF ₂ I group and/or a >CFI group. 2. The manufacturing method according to claim 1, wherein the first fluorine-containing polymer is perfluorocarbon-based. 3 Swelling the first fluorine-containing polymer in a solvent,
The manufacturing method according to claim 1, which comprises reacting with iodine in the presence of peroxide.