JPS588403B2 - Perfluorovinyl fluoropolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a fluoropolymer having a perfluorovinyl group in its side chain.

The perfluorovinyl group introduced into the side chain of the fluoropolymer is the crosslinking site or species of the polymer. Polymers with vinyl groups in their side chains can improve heat resistance, chemical resistance, and other properties, or add completely new properties to polymers because they act as reaction sites to introduce functional groups of species. You will be able to do this.

However, conventionally, it has been extremely difficult to produce such polymers having perfluorovinyl groups in their side chains, and no examples of producing such polymers have been reported yet.

During polymerization of a fluoromonomer having two or more vinyl groups, a fluoropolymer having a vinyl group may be partially produced by leaving only one of the vinyl groups.
It is extremely difficult to control and its manufacture is not reliable.

In view of the above circumstances, the present inventor conducted various studies on the production of fluoropolymers having perfluorinated vinyl groups in their side chains, and found that it was relatively easy to produce fluoropolymers having side chains with a specific structure. We have discovered a scale that can be converted into a fluoropolymer having perfluorovinyl groups as side chains, and provide such a novel method as the present invention.

That is, the present invention provides the side chain with -(0)l-(CF2)r-CO
A, or -(O)l-(CF2)r-2-CF(CF3
)-COA (where l=o or 1, r is 2 to 9, A is a fluorine atom, 10M or -NR1R2, M is an alkali metal, R1 and R2 are alkyl having 1 to 10 carbon atoms) A fluoropolymer having a perfluorinated vinyl group in its side chain is characterized by heat-treating a fluoropolymer having a perfluorinated vinyl group (representing a group) to convert the side chain to -(0)l-(CF2)r-2-CF=CF2. In the method of manufacturing polymers.

According to the present invention, a fluoropolymer having a vinyl group can be produced reliably and in a good yield by a relatively simple method, and the amount of vinyl groups in the side chain of the polymer can be reduced. It is also possible to appropriately control as necessary.

To explain the present invention in more detail below, the raw materials for the fluoropolymer having a vinyl group in the side chain of the present invention include =(0)l-(CF2)r-COA1 or -(0)l -(CF2)r-2-CF(CF3)-CO
Any polymer having A (l, r, A are the same as above) can be used, but due to its ease of manufacture,
Preferably, polymers with the following general formula are used.

In this 5, X, Suitably selected, l=O or 1, r=2 to 9, B is -(CF2)r
-COA or -(CF2)r-2-CF(CF3)-C
OA is S, and A is the same as above, but it is particularly preferable that A is OM and M is an alkali metal because the reaction is easy.

The polymers are usually fluorinated olefins and -COA.
or a polymerizable fluoromonomer containing a group convertible thereto, and optionally converting the group into -CO
Typical examples of fluorinated olefins used in this step include tetrafluoroethylene, trifluorochloroethylene, hexafluoropropylene, trifluoroethylene, and vinyl fluoride. Representative examples of polymerizable fluoromonomers containing a -COA group or a group convertible thereto include CF2-CF-(CF2)2-9COA', CF2=C
F-0-(CF2)COA', CF2=CF-0-(C
F2)-CF(CF3)-COA'.

In addition, A' represents A or a group convertible to A, and -OR can be converted to 10M by alkali treatment (wherein, R represents H or an alkyl group having about 1 to 10 carbon atoms). It also includes things like.

The polymerization of the above-mentioned fluorinated olefin and a polymerizable fluoromonomer containing a -COA group or a group convertible thereto, as well as a third monomer used as necessary, is carried out using an appropriate polymerization initiation source. Publication No. 48-2223, Special Publication No. 20788, Special Publication No. 48-419
This is carried out by the known method described in Japanese Patent No. 42.

The polymer is 5,000 to 1,000 due to the need for moldability and strength.
It is made to have a molecular weight of about 1,000,000, preferably 10,000 to 500,000, and is formed into an appropriate shape such as powder, granules, or a film.

The conversion from A' to A, which is carried out depending on the case, can be carried out before or after molding, but when A is 10M, from the viewpoint of moldability, for example, A' is -OR. It is preferable to form the precursor into a desired shape and then convert it to 10M with an appropriate alkali.

The side chain of the present invention thus produced includes (0)l-(cp2)r-COA or -(0)l-(C
F2) r-2-CF(CF3) A fluoropolymer with one COA can be heat-treated to transform the side chain into -(
0)l-(CF, ), -2-CF=CF2.

The heat treatment is preferably carried out at 150 to 350°C, particularly preferably 200 to 300°C, in air, vacuum, or inert gas, optionally under increased pressure or reduced pressure.

The heat treatment conditions mentioned above are related to the amount of side chains of the raw material polymer converted to vinyl groups, so by changing the conditions, the content of vinyl groups in the produced polymer can be controlled.

For example, the conversion rate to vinyl groups can be increased by increasing the heat treatment temperature or by lengthening the heat treatment time.

It goes without saying that the content of side chain vinyl groups in the produced polymer can be controlled by the content of the polymerizable fluoromonomer having a -COA group or a group convertible thereto in the copolymer.

The thus produced fluoropolymer having a vinyl group in its side chain can be modified by introducing various functional groups by reacting the vinyl group with various reagents, as described above. Is possible.

For example, the polymer may include SO2F2, COF2, H3P.
By adding O4 or halogen (ICl, I2, Br2, etc.), the side chains of the polymer are converted to -CFSO2F.
CF3,-CFCOFCF3-CFH2PO4CF2H
, -CFICF2Cl (with addition of ICl), and the vinyl group can be a reactive site of a crosslinking monomer or a grafting point for graft polymerization.

Examples are shown below to more specifically illustrate the present invention, but it goes without saying that the present invention is not limited to the above description and the following examples.

Example 1 A film consisting of a copolymer of tetrafluoroethylene and methyl perfluoro-5-oxer-6-heptenoate (content of the latter 13 moles) was prepared in water/methanol/NaOH.
(weight ratio 50/20/30) and refluxed for 4 hours to convert the side chain carboxyl group to its sodium salt.

The obtained film was boiled to remove the alkali content, and further dried under reduced pressure at 100°C.

Regarding the Kameru film, as shown in Table 1, 2
Heat treatment was performed at a temperature of 00 to 250°C for several tens of minutes to several hours.

In order to examine the results of such heat treatment, infrared absorption spectroscopy was used to investigate the effects of vinyl groups (179
0Cm-1) and carboxylate (1680Cm-1')
The amount of vinyl groups in the produced polymer (mole ratio) and its conversion rate (mole ratio) were calculated.

Table 1 Heat treatment conditions Vinyl group content Conversion rate amount (mole ratio) (mole ratio) No. I 225℃, 30 minutes 1.3 10
No. 2 230℃, 〃 3.6
28 No. 3 230℃, 60 minutes 5.5
42 No. 4 240℃, 30 minutes 9.1 7
ONo. 5 250°C, 〃10.5 81 Example 2 A film consisting of a copolymer of tetrafluoroethylene and methyl perfluoro 2 methyl pentanoate (the content of the latter was 3 mol) was prepared in the same manner as in Example 1 to remove side chains. The carboxylic ester was converted to the sodium salt and dried.

This film was heat treated at 230°C for 30 minutes.

According to infrared absorption spectrum analysis, the vinyl group content is 0.8
He was in charge of the mall.

The conversion rate is 27. Example 3 A powder of a copolymer of ethylene tetrafluoride and a fluoride of formula (the content of the latter was 10 mol) was heat treated at 250° C. for 8 hours.

According to infrared absorption spectrum analysis, the vinyl group content was 3 moles.

The conversion rate is 30. Example 4 A powder of a copolymer of ethylene tetrafluoride and an acid amide represented by the formula CF2=CFO(CF2)3CONH2 (the content of the latter being 7 mol) was mixed with potassium carbonate powder and then heated at 250°C for 3 hours. Processed.

It was pickled, dried and formed into a film, and then treated in an aqueous sodium hydroxide solution.

The vinyl group content of the film was determined by infrared absorption spectrum analysis to be 1 molar, and the conversion rate was 14 molar.

Claims (1)

[Claims] 1 side chain, one(0)z-(CF2), one COA. or (0)l-(CF2)L2-CF(CF3)-C
OA (where l=o or 1, r=2 to 9, A is a fluorine atom, -0M or -NR1R2, M is an alkali metal, R1 and R2 are an alkyl group having 1 to 10 carbon atoms) A fluoropolymer having a perfluorinated vinyl group in its side chain is characterized in that the fluoropolymer having a perfluorinated vinyl group is heat-treated (4) to convert the side chain to -(0)l-(CF2)r2-CF=CF2. manufacturing method.