JP4453300B2 - 2,2,3,3,4,5-Hexafluoro-2,3-dihydrofuran and polymer containing the monomer - Google Patents

Description

  The present invention relates to a novel fluorine-containing monomer and a novel fluorine-containing polymer obtained from the fluorine-containing monomer.

  A fluororesin such as polytetrafluoroethylene (PTFE) has been used as a material and a protective material for electronic parts because it has chemical stability, thermal stability, electrical characteristics, and chemical resistance. However, general-purpose fluororesins such as PTFE have a drawback of low transparency due to high crystallinity of the polymer main chain.

  On the other hand, it is known that a fluororesin having a saturated ring structure in the main chain is amorphous and can be a transparent fluororesin. The transparent fluororesin is used as a transparent coating material, optical material or the like.

  Special monomers such as perfluoro (3-butenyl vinyl ether) and perfluoro (2,2-dimethyl-1,3-dioxole) are known as monomers for producing a fluororesin having a ring structure. (See Patent Document 1).

U.S. Pat. No. 3,865,845 (page 3)

  Although the production process of these monomers is long and the yield is extremely low, development of monomers having various saturated ring structures and a polymerizable double bond in a part of the ring structure has been desired. The monomers proposed are perfluoro (2,2-dimethyl-1,3-dioxole) and perfluoro (1,4-dioxene), and it is hoped that more monomers can be developed. It was rare.

  The present inventors have made various studies for the purpose of obtaining a polymerizable monomer that can be copolymerized with various comonomers, is perfluorinated, and has a ring structure. As a result, a perfluoro monomer having a furan ring skeleton achieves the object, and a polymerized unit of the monomer (the “polymerized unit” in the present invention can be formed when a polymerizable monomer is polymerized. The polymer containing a repeating unit derived from the polymerizable monomer) has been found to have effective physical properties. Further, it has been found that the polymerized units of the monomer can be introduced into the polymer at a high rate, and the obtained polymer can introduce a saturated ring structure into the main chain at a high rate.

That is, the present invention provides the following inventions.
(1) 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran.
(2) A polymerizable monomer comprising 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran.
(3) homopolymerizing 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran, or 2,2,3,3,4,5-hexafluoro-2,3-dihydro A method for producing a fluorine-containing polymer essentially comprising a polymer unit represented by the following formula (2), wherein furan is copolymerized with at least one other polymerizable monomer.

  (4) A fluorinated polymer comprising polymerized units represented by the following formula (2) and having a molecular weight of 500 to 1,000,000, or a polymerized unit of a polymerized unit represented by formula (2) and another polymerizable monomer A fluorine-containing polymer having a molecular weight of 500 to 1,000,000 and having a polymerized unit of another polymerizable monomer, it is represented by the formula (2) in the fluorine-containing polymer. A fluorine-containing polymer, wherein the proportion of polymerized units is 0.01% by mass or more and less than 100% by mass.

  2,2,3,3,4,5-Hexafluoro-2,3-dihydrofuran provided by the present invention is a novel compound and a useful compound as a fluorine-containing monomer. Moreover, in the polymer which polymerized this fluorine-containing monomer, the ratio of the polymerization unit derived from this monomer can be changed arbitrarily. Further, the fluoromonomer can provide a low refractive index fluororesin excellent in transparency. In addition, since the polymer obtained by polymerizing the fluorine-containing monomer of the present invention is soluble in a fluorine-based solvent, a low reflection processing material, a chemical-resistant coating material, a water- and oil-repellent material, an optical fiber core and a cladding material Application to optical waveguide materials, electronic component materials, film materials, etc. can be made easier. Furthermore, the physical properties of the polymer can be improved by copolymerizing the fluorine-containing monomer of the present invention by using it as a second component in the polymerization of other polymerizable monomers (especially other monomers containing fluorine atoms). .

  The 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran of the present invention is a compound represented by the following formula (1).

  2,2,3,3,4,5-Hexafluoro-2,3-dihydrofuran represented by the formula (1) is obtained by using tetrahydrofurfuryl alcohol, which is industrially available at a low cost, as a raw material. (See WO00 / 56694, WO02 / 4397, etc.).

That is, tetrahydrofurfuryl alcohol is reacted with a fluorine-containing group and a compound having a —COX (X represents a fluorine atom or a chlorine atom) group to form a partially fluorinated ester, and in the partially fluorinated ester, The C—H structure is fluorinated by fluorination reaction such as liquid phase fluorination and substituted with C—F, and then the ester is thermally decomposed, or the ester bond of the ester is decomposed and then thermally decomposed. Can be manufactured. A typical example of the production method can be represented by the following general formula. However, X in the formula represents a fluorine atom or a chlorine atom as described above, Q represents an n-valent fluorinated organic group, Q ^f represents a perfluorinated n-valent organic group, and n represents Q or It means the number of groups bonded to Q ^f and is an integer of 1 or more.

That is, a compound (A-1) and 2-tetrahydrofurfuryl alcohol are reacted to obtain a compound (A-2), and the compound (A-2) is perfluorinated to obtain a compound (A-3). Next, the compound (A-3) is thermally decomposed to obtain the compound represented by the formula (1), or the ester bond of the compound (A-3) is decomposed to obtain the compound (A-4). Examples thereof include a method of obtaining the compound represented by the formula (1) by thermally decomposing the compound (A-4) after it is obtained. The conditions of each reaction step of the above reaction and the operation method during the reaction can be carried out according to the conditions and methods described in WO00 / 56694, WO02 / 4397 and the like. Incidentally, Q is preferably the same group as Q ^f, X is preferably a fluorine atom, n represents is preferably an integer of 1 to 4.

  In addition, the present invention homopolymerizes 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran, or 2,2,3,3,4,5-hexafluoro-2,3. -Provided is a method for producing a fluorine-containing polymer in which dihydrofuran and one or more other polymerizable monomers are copolymerized, and a fluorine-containing copolymer that can be produced by the production method. The molecular weight of the fluoropolymer of the present invention is preferably from 500 to 1,000,000, particularly preferably from 500 to 200,000, particularly preferably from 500 to 100,000, and further preferably from 500 to 10,000.

  The fluorine-containing copolymer of the present invention is a polymer having a saturated ring structure in the main chain and can be a transparent fluororesin. The fluorine-containing copolymer of the present invention having a polymerization unit of 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran as essential is a known perfluoro (3-butenyl vinyl ether) ( Hereinafter, it is also referred to as BVE.) And a polymer having a saturated ring structure in the main chain in common with the polymer obtained by cyclopolymerization. The structure of a polymer obtained by homocyclopolymerization of BVE and the structure of a polymer obtained by completely alternating copolymerization of 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran and tetrafluoroethylene Are both polymers that can be distinguished in terms of the structure of the end groups. Further, in the BVE copolymer, it is very difficult to change the proportion of the ring structure in the copolymer, and a copolymer having a ring structure of a certain degree or more cannot be obtained. According to the polymerization reaction using 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran of the present invention, the ratio of the ring structure can be arbitrarily selected, The kind of the polymerizable monomer and the copolymerization ratio can also be arbitrarily changed.

Examples of other polymerizable monomers include not only fluorine-containing monomers but also non-fluorinated monomers, and various monomers having radical polymerizability can be employed. Examples include fluorine-containing monomers, hydrocarbon monomers, and other monomers; olefins such as ethylene and propylene; fluoroolefins such as tetrafluoroethylene and vinylidene fluoride; fluorine-containing vinyl ethers such as perfluoro (alkyl vinyl ether) _{s; CF 2 = CFO (CF 2} ) 3 COOCH 3, CF 2 = CFOCF 2 CF (CF 3) fluorine-containing vinyl ethers containing OCF 2 _CF 2 SO ₂ F reactive group such as; BVE, perfluoro (allyl Fluorinated monomers capable of cyclopolymerization such as vinyl ether); monomers having a fluorinated saturated ring structure such as perfluoro (2,2-dimethyl-1,3-dioxole), and the like, and olefins, fluoroolefins, Fluorine-containing monomers capable of cyclopolymerization are preferred .

  Further, in the fluorine-containing copolymer of the present invention in the case where fluorine-containing vinyl ethers containing a reactive group are copolymerized, the reactive group may be derivatized with another group. Moreover, you may use together the fluorine-containing copolymer of this invention with the other compound (for example, crosslinking agent etc.) which can react with a reactive group.

The other polymerizable monomer may be one type or two or more types. By copolymerizing the other polymerizable monomer as the second component monomer, a fluororesin having excellent characteristics can be provided. In particular, when the fluorine-containing copolymer of the present invention is a copolymer of 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran and tetrafluoroethylene, tetrafluoro By changing the copolymerization ratio of ethylene, a copolymer having an arbitrary glass transition temperature (T _g ) can be produced. For example, by reducing the proportion of tetrafurfuryl Roo ethylene, it can produce a copolymer of high T _g.

  When the fluoropolymer of the present invention is a copolymer of 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran and one or more other polymerizable monomers, The proportion of 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran polymerized units (hereinafter also referred to as polymerized units A) is 0.01% by mass or more based on the total polymerized units. And less than 100% by weight. The arrangement of the polymer units in the copolymer is preferably block, random, or graft, and particularly preferably random.

  In the case where the fluoropolymer of the present invention is a copolymer and the ratio of the polymerization unit A is as small as about 0.01 to 1.0 mol%, the copolymer is obtained by polymerizing only other polymerizable monomers. Compared with a polymer, a remarkable improvement effect of physical properties can be expected. For example, when a copolymer with tetrafluoroethylene is used, the melt moldability can be remarkably improved as compared with polytetrafluoroethylene (PTFE).

On the other hand, the polymer in the case the proportion of the polymerized units A frequently as about 30 to 100% by mass, tends to polymer becomes transparent, trend of high T _g of, and, is observed a tendency that solubility in solvent is enhanced. This is because, when the fluoropolymer of the present invention contains a saturated ring structure in a high proportion in the main chain, the crystallinity of the main chain is broken, and it has amorphous characteristics, so that transparency and good dissolution in a solvent are achieved. It is thought that it can achieve sex. In the copolymer obtained by the BVE such copolymerizable believed high T _g can be attained.

  The manufacturing method of the fluoropolymer of this invention is not specifically limited, It is preferable to manufacture by radical polymerization reaction. The radical polymerization reaction is preferably carried out under the action of a radical polymerization initiator. As the radical polymerization initiator, a general polymerization initiator for radical polymerization can be used, and an azo compound, an organic peroxide can be used. Inorganic peroxides are preferred examples.

Specific examples of the radical polymerization initiator include 2,2′-azobis (2-aminopropane) dihydrochloride, 4,4′-azobis (4-cyanopentanoic acid), 2,2′-azobis (4- Azo compounds such as methoxy-2,4-dimethylvaleronitrile), 1,1′-azobis (1-cyclohexanecarbonitrile); methyl ethyl ketone peroxide, benzoyl peroxide, ((CH ₃ ) ₂ CHOCOO) ₂ , perfluorobenzoyl Peroxide, perfluorobutyryl peroxide, perfluorononanoyl peroxide, organic peroxide such as C (CF ₃ ) ₃ —O—C (CF ₃ ) ₃ ; K ₂ S ₂ O ₈ , (NH ₄ ) ₂ And inorganic peroxides such as S ₂ O ₈ .

  Polymerization methods include bulk polymerization in which monomers are polymerized as they are, solution polymerization in a solvent in which the monomers are dissolved, suspension polymerization in the presence or absence of a suitable organic solvent in an aqueous medium, and in an aqueous medium. Examples thereof include emulsion polymerization carried out in the presence of an emulsifier.

Solvents that can be used for polymerization include water; ketones such as acetone; esters such as ethyl acetate; ethers such as tetrahydrofuran; aromatic hydrocarbons such as benzene and toluene; trichlorotrifluoroethane, dichloropentafluoropropane, Perfluorochlorinated alkane [F (CFClCF ₂ ) _n Cl, where n is an integer of 1-7. Chlorofluorohydrocarbons such as]; perfluorobenzene, perfluoro (2-butyl tetrahydrofuran), perfluoro trialkyl amines _{[N (C n F 2n +} 1) 3, where n is an integer of 2 to 4. ], Perfluoroalkane _{[C n F 2n + 2,} wherein n is 6-8 integer. ] Fluorinated solvents such as nonafluorobutyl methyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoropentane, tridecafluorohexane, etc. And solvents such as hydrogenated fluorinated ethers. When using a solvent at the time of superposition | polymerization, the solvent may be 1 type or may be 2 or more types.

  There are no particular limitations on the reaction conditions (temperature, pressure, etc.) during the polymerization. The reaction conditions can be appropriately changed in consideration of the boiling point of the monomer used for the polymerization, the heating source, the method for removing the polymerization heat, and the like. In the usual case, the polymerization temperature is preferably from 0C to 200C, particularly preferably from 10C to 150C, particularly preferably from 30C to 120C, and further preferably from 30C to 100C. The polymerization pressure may be reduced or increased. Usually, normal pressure to 2 MPa (gauge pressure) is preferable, normal pressure to 1 MPa (gauge pressure) is particularly preferable, and normal pressure to 0.5 MPa is particularly preferable.

The fluorine-containing polymer provided by the present invention can exhibit high solvent solubility when compared with a polymer obtained by cyclopolymerization. The solvent is appropriately changed depending on the structure and molecular weight of the fluorine-containing polymer, but a fluorine-containing organic solvent is preferable, and in particular, hexafluorobenzene, perfluoro (2-butyltetrahydrofuran), perfluorotributylamine, Perfluorohydrocarbons such as fluorodecalin, perfluoro (methyldecalin), perfluorocyclohexane, perfluorohexane, perfluorooctane, and perfluorohydrocarbons such as C ₆ F ₁₃ H and C ₈ F ₁₇ C ₂ H ₅ , Fluoroaromatics such as 1,3-trifluoromethylbenzene are preferred.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these. In addition, _Mw shows a weight average molecular weight and _Mn shows a number average molecular weight. In the examples, the gel permeation chromatographic method is referred to as GPC method. The measurement method of the GPC method was according to the method described in JP-A-2000-74892. Specifically, a mixed solution of CF ₂ ClCF ₂ CFHCl and (CF ₃ ) ₂ CHOH (volume ratio 99: 1) was used as a mobile phase as a mobile phase, and PLgel 5 μm MIXED-C (inner diameter 7) manufactured by Polymer Laboratories. 0.5 mm, 30 cm in length) were connected in series to form an analytical column. As a standard sample for molecular weight measurement, a calibration curve was prepared using 10 kinds of polymethyl methacrylate (manufactured by Polymer Laboratories) having a molecular weight distribution (M _w / M _n ) of less than 1.17 and a molecular weight of 1,000 to 2,000,000. The mobile phase flow rate was 1.0 ml / min, the column temperature was 37 ° C., the detector was an evaporative light scattering detector, and the molecular weight was determined as the polymethylmethacrylate equivalent molecular weight.

[Example 1]
(Example 1-1) Esterification reaction

2-Tetrahydrofurfuryl alcohol (20 g) and (CH ₃ CH ₂ ) ₃ N (21.8 g) were placed in a flask and stirred in an ice bath. FCOCF (CF ₃ ) OCF ₂ CF ₂ CF ₃ (71.5 g) was added dropwise over 1 hour while maintaining the internal temperature of the flask at 10 ° C. or lower. After completion of dropping, the mixture was further stirred at 25 ° C. for 2 hours. Next, water (50 mL) was added while maintaining the internal temperature of the flask at 15 ° C. or lower to obtain a reaction solution separated into two layers.

  The reaction solution was separated, and the lower layer was washed twice with water (50 mL), dried over magnesium sulfate, and then filtered to obtain a crude liquid. The target ester compound (66.3 g) was obtained by distillation under reduced pressure as a fraction of 88 to 89 ° C./2.7 kPa (absolute pressure). The GC purity was 98%. The formation of compound (A-20) was confirmed by NMR analysis.

¹ H-NMR (300.4 MHz, CDCl ₃ , TMS) δ (ppm): 1.60 to 1.73 (m, 1H), 1.86 to 2.10 (m, 3H), 3.76 to 3 .91 (m, 2H), 4.14 to 4.22 (m, 1H), 4.28 to 4.47 (m, 2H).
¹⁹ F-NMR (282.7 MHz, CDCl ₃ , CFCl ₃ ) δ (ppm): −79.9 (1F), −81.3 (3F), −82.1 (3F), −86.4 (1F) ), -129.5 (2F), -131.5 (1F).

  (Example 1-2) Fluorination reaction

  1,1,2-Trichloro-1,2,2-trifluoroethane (hereinafter abbreviated as R-113) (313 g) was added to a 500 mL nickel autoclave, and the mixture was stirred and kept at 25 ° C. At the autoclave gas outlet, a cooler maintained at 20 ° C., a packed bed of NaF pellets, and a cooler maintained at −10 ° C. were installed in series. In addition, the liquid return line for returning the condensed liquid to the autoclave was installed from the cooler kept at -10 ° C. After blowing nitrogen gas for 1.0 hour, fluorine gas diluted to 20% with nitrogen gas was blown for 1 hour at a flow rate of 8.08 L / h. Next, while blowing fluorine gas at the same flow rate, a solution obtained by dissolving the compound (A-20) (5.01 g) obtained by esterification in R-113 (100 g) was injected over 4.7 hours.

Furthermore, while blowing fluorine gas at the same flow rate, 9 mL of R-113 solution having a benzene concentration of 0.01 g / mL was injected while raising the temperature from 25 ° C. to 40 ° C., and the benzene inlet of the autoclave was closed, and further the autoclave After the outlet valve was closed and the pressure reached 0.20 MPa, the fluorine gas inlet valve of the autoclave was closed, and stirring was continued for 0.4 hours. Next, while maintaining the pressure in the reactor at 40 ° C., 6 mL of the above benzene solution was injected, the benzene inlet of the autoclave was closed, the outlet valve of the autoclave was closed, and the pressure was adjusted to 0.20 MPa. Then, the fluorine gas inlet valve of the autoclave was closed and stirring was continued for 0.4 hours. Further, the same operation was repeated three times. The total amount of benzene injected was 0.33 g, and the total amount of R-113 injected was 33 mL. Further, nitrogen gas was blown for 1.0 hour. As a result of quantifying the target product by ¹⁹ F-NMR, it was confirmed that Compound (A-30) was produced, and the yield was 64%.

¹⁹ F-NMR (376.0 MHz, CDCl ₃ , CFCl ₃ ) δ (ppm): −80.3 (1F), −81.9 (3F), −82.1 (3F), −83.5 to − 84.8 (2F), -85.5 to -88.0 (3F), -126.5 (1F), -127.4 (1F), -128.1 (1F), -130.2 (2F) ), -130.4 (1F), -132.2 (1F), -135.8 (1F).

  (Example 1-3) Thermal decomposition reaction of perfluoroester

Compound (A-30) (2.1 g) obtained by fluorination was charged into a flask together with NaF powder (0.02 g), and heated in an oil bath at 140 ° C. for 10 hours with vigorous stirring. A reflux condenser whose temperature was adjusted to −10 ° C. was installed at the top of the flask. After cooling, a liquid sample (2.0 g) was recovered, and this was precision distilled to recover compound (A-40) (0.8 g). The structure of the compound (A-40) was confirmed by ¹⁹ F-NMR.

¹⁹ F-NMR (376.0 MHz, CDCl ₃ , CFCl ₃ ) δ (ppm): 26.6 to 26.3 (1F), −82.6 to −83.9 (2F), −117.9 to − 118.3 (1F), -125.7 to -127.0 (2F), -128.9 to -129.9 (1F), -134.4 to -135.3 (1F).

  (Example 1-4) 2,3,4,4,5,5-hexafluoro-2,3-dihydrofuran synthesis reaction

  A tubular reaction tube having an inner diameter of 5.2 cm was filled with soda glass beads (800 ml, trademark: Gakunan # 150) and heated to 390 ° C. By flowing nitrogen gas from the lower part of the reactor at a flow rate of 2.7 mol / h, a fluidized bed state is obtained, and the compound (A-40) is flowed with nitrogen gas at 91 g / h (0.37 mol / h). The reaction was carried out. The reaction crude gas from the reactor outlet was recovered in a dry ice cooling trap and a liquid nitrogen cooling trap connected thereafter. After reacting 662 g (2.7 mol) of the raw material, only nitrogen gas was supplied for 1 hour to collect all the reaction component gases remaining in the reactor. The nitrogen gas trap was gradually heated to the dry ice cooling temperature after completion of the reaction, and all components that vaporized at this temperature were purged and then recovered as a collected gas. The crude product recovered in the dry ice cooling trap and the liquid nitrogen cooling trap was combined to recover 450 g of crude liquid. As a result of analyzing the recovered liquid by GC, the raw material contained 10 mol%, the compound (1) contained 70%, and the compound (1) isomer represented by the following formula contained 10%.

The recovered crude liquid was purified by distillation under pressure (0.5 MPa), compound (1) was isolated and confirmed to have the following structure by ¹⁹ F-NMR and GC-Mass spectrum (EI detection) analysis.

¹⁹ F-NMR (282.7 MHz, CDCl ₃ , CFCl ₃ ) δ ppm: (−92.60 ppm, bs, 2F, Fa), (−113.95 ppm, dd, 2F, Jb−c = 11 Hz, Jb−d = 11 Hz, Fb), (−202.03 ppm, dt, 1F, Jc−d = 20 Hz, Jc−b = 11 Hz, Fc), (−107.90 ppm, dt, 1F, Jd−c = 20 Hz, Jd−b = 11 Hz, Fd).

Mass (EI method) m / z: 178 (M ⁺ ), 159, 131, 128, 112, 109, 100, 93, 81, 69, 62, 50, 47 (calculated Exact mass of C ₄ F ₆ O: 177 .99).

[Example 2]
BVE (15 g), ion-exchanged water (150 g) and a polymerization initiator (((CH ₃ ) ₂ CHOCOO) ₂ , 90 mg) were placed in a pressure-resistant glass autoclave having an internal volume of 200 mL. After performing nitrogen substitution in the system three times, the compound (1) (15 g) was introduced, pressurized to 0.4 MPa with nitrogen, and suspension polymerization was performed at 40 ° C. for 22 hours. As a result, a polymer A (16 g) was obtained. The intrinsic viscosity [η] of the polymer was 0.40 at 30 ° C. in perfluoro (2-butyltetrahydrofuran). The glass transition point (T _g ) of the polymer A was 128 ° C., and it was a tough and transparent glassy polymer at room temperature. The 10% thermal decomposition temperature was 460 ° C. and the refractive index was 1.33. In the ¹⁹ F-NMR spectrum of the polymer A, it was confirmed that the peak of the fluorine atom bonded to the carbon atom constituting the unsaturated bond disappeared completely and the furan ring structure was retained.

[Example 3]
Perfluoro (2-butyltetrahydrofuran) (20 g) and C (CF ₃ ) ₃ —O—O—C (CF ₃ ) ₃ (40 mg) as a polymerization initiator were placed in a stainless steel autoclave having an internal volume of 100 mL. Replacement with nitrogen gas was performed. Thereafter, the autoclave was cooled to −78 ° C. in a dry ice / ethanol bath, and the compound (1) (12.0 g) obtained in Example 1-4 was charged. Thereafter, the inside of the system was pressurized to 0.5 MPa with nitrogen gas and polymerized at 100 ° C. for 36 hours. As a result, a polymer (hereinafter referred to as polymer B) (0.6 g) was obtained. As a result of measuring ¹⁹ F-NMR of the polymer B, it was confirmed that the peak of the fluorine atom bonded to the carbon atom constituting the unsaturated bond had disappeared completely and that the furan ring structure was retained.

The _Mw of the polymer B was 1350 by the GPC method. Polymer B was a tough and transparent glassy polymer at room temperature. As a result of measuring a _{T g} in differential scanning calorimetry (DSC method) was 70 ° C..

[Example 4]
Perfluoro (2-butyltetrahydrofuran) (20 g) and a polymerization initiator (((CH ₃ ) ₂ CHOCOO) ₂ , 15.4 mg) were placed in a stainless steel autoclave with an internal volume of 100 mL, and the system was replaced with nitrogen gas. . Thereafter, the autoclave was cooled to −78 ° C. in a dry ice / ethanol bath, and the compound (1) (5.0 g) and vinylidene fluoride (0.54 g) obtained in Example 1-4 were charged. Thereafter, the inside of the system was pressurized to 0.2 MPa with nitrogen gas, and polymerization was performed at 40 ° C. for 24 hours and further at 50 ° C. for 20 hours. As a result, a polymer (hereinafter referred to as polymer C) (2.5 g) was obtained. As a result of measuring ¹⁹ F-NMR of the polymer C, the ratio of the polymer unit of the compound (1) to the total polymer unit in the polymer C is 46 mol%, and the ratio of the polymer unit of vinylidene fluoride is 54 mol. %Met. Further, in the ¹⁹ F-NMR spectrum of the polymer C, it was confirmed that the peak of the fluorine atom bonded to the carbon atom constituting the unsaturated bond had completely disappeared and the furan ring structure was retained. .

The _Mw of the polymer C was 75000 from the GPC method. Further, the polymer C was a tough and transparent glassy polymer at room temperature. The 10% weight loss temperature of this polymer was 443 ° C. as measured by thermogravimetric analysis in nitrogen. Further, _{T g} measured by DSC method was 80 ° C..

[Example 5]
Perfluoro (2-butyltetrahydrofuran) (5 g) and CF ₂ ═CHCF (CF ₃ ) CF ₂ OCF═CF ₂ (hereinafter abbreviated as 5M monomer) (8.7 g), C (CF ₃ as a polymerization initiator) ) ₃ -O—O—C (CF ₃ ) ₃ (60 mg) was placed in an autoclave (stainless steel, internal volume 100 mL), the system was replaced with nitrogen gas, and then the autoclave was placed in a dry ice / ethanol bath. Cooled to -78 ° C. The compound (1) (6.5 g) obtained in Example 1-4 was charged into an autoclave. Thereafter, the inside of the system was pressurized to 0.2 MPa with nitrogen gas, and polymerization was carried out at 95 ° C. for 20 hours and further at 100 ° C. for 48 hours. As a result, a polymer (hereinafter referred to as polymer D) (6.3 g) was obtained. As a result of measuring ¹⁹ F-NMR of the polymer D, the ratio of the polymer unit of the compound (1) to the total polymer unit in the polymer D is 25 mol%, and the ratio of the polymer unit of the 5M monomer is 75 mol%. Met. Further, in the ¹⁹ F-NMR spectrum of the polymer D, it was confirmed that the peak of the fluorine atom bonded to the carbon atom constituting the unsaturated bond had disappeared completely and that the furan ring structure was retained. .

The _Mw of the polymer D was 22000 from the GPC method. The polymer D was a tough and transparent glassy polymer at room temperature. As a result of measurement by the DSC method, _{T g} was 90 ° C..

  The fluoropolymer of the present invention can be used as a tube, a wire coating material, or the like by melt molding. Further, the fluoropolymer of the present invention is used as a low reflection processing material, a chemical resistant coating material, a water and oil repellent material, an optical fiber core and cladding material, an optical waveguide material, an electronic component material, a film material, etc. it can.

  Further, since the fluoropolymer of the present invention can have a low dielectric constant, it can be used as a protective film for semiconductor elements. Further, since the water-absorbing rate of the fluoropolymer can be lowered, the semiconductor element can be shielded from moisture. That is, the fluorine-containing polymer of the present invention is an interlayer insulating film (for example, for semiconductor elements, liquid crystal displays, multilayer wiring boards, etc.), buffer coat film, passivation film, α-ray shielding film, element sealing material, It can be used as an adhesive for semiconductors (for example, for LOC, die bonding, etc.), an interlayer insulating film for high-density mounting substrates, high-frequency elements (for example, RF circuit elements, GaAs elements, InP elements, etc.), moisture-proof films, and protective films.

Furthermore, the fluoropolymer of the present invention can be used alone as a film or as a film laminated with a resin such as polyimide. The film can be used as a circuit board film or a film capacitor.

Claims (4)

  2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran.   A polymerizable monomer comprising 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran. 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran is homopolymerized, or 2,2,3,3,4,5-hexafluoro-2,3-dihydrofuran and others A method for producing a fluorine-containing polymer essentially comprising a polymer unit represented by the following formula (2), wherein at least one of the polymerizable monomers is copolymerized.

A fluorine-containing polymer consisting of polymerized units represented by the following formula (2) and having a molecular weight of 500 to 1,000,000, or one of polymerized units represented by formula (2) and other polymerizable monomers It is a fluorine-containing polymer having a molecular weight of 500 to 1,000,000 as described above, and when it contains polymerized units of other polymerizable monomers, the polymer unit represented by the formula (2) in the fluorine-containing polymer A fluorine-containing polymer, wherein the ratio is 0.01% by mass or more and less than 100% by mass.