JP3071342B2 - Fluorine-containing random copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluorine-containing random copolymer. Specifically, the present invention provides a fluorine-containing random copolymer having improved mechanical strength.

[0002]

2. Description of the Related Art Fluororesins are manufactured in various types due to their excellent properties of chemical resistance, heat resistance, melt moldability and electrical properties, and are used in a wide range of industrial fields due to their excellent properties. ing. For example, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (hereinafter referred to as PFA) is well known and widely used as a melt-moldable fluororesin.

Japanese Patent Application Laid-Open No. 2-276808 discloses that tetrafluoroethylene and CF ₂ ＝ CFOCH ₂ (C
F ₂ ) _n X (where X is a hydrogen atom or fluorine, chlorine and bromine, and n is an integer of 1 or more). This copolymer has the characteristic of exhibiting very good copolymerizability. The obtained copolymer has the same chemical resistance, mechanical strength, and electrical properties as conventional fluororesins.

[0004]

However, the conventional P
The fluororesin including FA has a problem that mechanical strength such as tensile breaking strength and bending life is lower than other engineering plastics.

In order to improve the tensile strength at break and the bending life, a method of increasing the molecular weight is conceivable. However, when the molecular weight is increased, the specific melt viscosity increases and the melt formability decreases. In order to improve the bending life, it has been proposed to increase the number of carbon atoms in the side chain based on the fluorine-containing vinyl ether contained therein, or to increase the content of the fluorine-containing vinyl ether contained therein (see, for example, Japanese Patent Application Laid-Open No. H11-157572). Japanese Patent Application No. 5-2007) has a problem that other mechanical strengths such as tensile breaking strength are not sufficient.

[0006] From such a background, there has been a demand for the development of a fluorocopolymer having good mechanical strength such as tensile breaking strength and bending life.

[0007]

Means for Solving the Problems The present inventors have intensively studied a fluorine-containing copolymer which has solved the above-mentioned disadvantages. As a result, a copolymer composed of a monomer unit based on tetrafluoroethylene and a monomer unit based on fluorine-containing vinyl ether having two specific structures, and each monomer unit having a specific composition, The inventors have found that they exhibit excellent mechanical strength such as tensile breaking strength and bending life, and have completed the present invention.

That is, the present invention provides: (A) a compound represented by the following general formula (I):

[0009]

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(B) i) a monomer unit based on tetrafluoroethylene represented by the following formula:

[0011]

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(Where n is an integer of 1 to 3 and X ¹ is a hydrogen atom or a halogen atom); and ii) a monomer unit based on a short-chain fluorine-containing vinyl ether represented by the following general formula (III): )

[0013]

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(Where m is an integer of 5 to 20, and X ²
Is a hydrogen atom or a halogen atom. A) a monomer unit based on a short-chain fluorinated vinyl ether and a monomer unit based on a long-chain fluorinated vinyl ether comprising 1 to 10 mol% in total of a monomer unit based on a long-chain fluorinated vinyl ether Of the monomer units based on the long-chain fluorinated vinyl ether in the total of 40 to 99 mol%, and the specific melt viscosity measured at 372 ° C. is 1 × 10 ² to 1 ×.
10 ⁷ poise is a fluorine-containing random copolymer.

In the present invention, a monomer unit based on tetrafluoroethylene represented by the above (I), a monomer unit based on a short-chain fluorine-containing vinyl ether represented by the above formula (II), and a monomer unit based on the above formula (III) ) That the monomer unit based on long-chain fluorinated vinyl ether is copolymerized at a specific composition ratio, and that the resulting fluorinated random copolymer has mechanical properties such as tensile rupture strength and bending life. This is important for achieving excellent strength.

In the present invention, the monomer unit based on tetrafluoroethylene is represented by the general formula (I):

[0017]

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Is a monomer unit represented by the formula:

Further, the above-mentioned general formula (II)

[0020]

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In the monomer unit based on the short-chain fluorine-containing vinyl ether represented by the formula, n is an integer of 1 to 3.
X ¹ is a hydrogen atom or a halogen atom,
A hydrogen atom or a fluorine atom is desirable from the viewpoint of thermal stability.

Further, the above-mentioned general formula (III)

[0023]

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In the monomer unit based on the long-chain fluorine-containing vinyl ether represented by the formula, m is an integer of 5 to 20, but m is preferably an integer of 5 to 8 in view of availability of raw materials. X ² is a hydrogen atom or a halogen atom, and is preferably a hydrogen atom or a fluorine atom from the viewpoint of chemical and thermal stability.

In the fluorine-containing random copolymer of the present invention, the monomer unit based on tetrafluoroethylene represented by the general formula (I) is 90 to 99 mol%, preferably 95 to 99 mol%.
And a monomer unit based on the short-chain fluorinated vinyl ether represented by the general formula (II) and a monomer unit based on the long-chain fluorinated vinyl ether represented by the general formula (III). 1 to 10 mol%, preferably 1 to 5 mol%. When the monomer unit based on tetrafluoroethylene is less than 90 mol%, the resulting fluorine-containing random copolymer has a low softening temperature, which is not preferable because of a problem in moldability. On the other hand, when the monomer unit based on tetrafluoroethylene is more than 99 mol%, the obtained fluorine-containing random copolymer is
The specific melt viscosity becomes too high, resulting in a copolymer having poor moldability.

Further, in the fluorine-containing random copolymer of the present invention, a monomer unit based on the short-chain fluorine-containing vinyl ether represented by the above formula (II) and a long-chain fluorine-containing fluorine-containing compound represented by the above formula (III) The proportion of the monomer unit based on the long-chain fluorine-containing vinyl ether in the total of the monomer units based on the vinyl ether is 40 to 99 mol%, preferably 50 to 99 mol%. When the ratio of the monomer unit based on the long-chain fluorine-containing vinyl ether is 40,
When it is less than mol%, the resulting copolymer has a high tensile strength at break but does not improve the bending life. On the other hand, when the proportion of the monomer unit based on the long-chain fluorine-containing vinyl ether is larger than 99 mol%, the obtained copolymer has a high folding life but does not improve the tensile strength at break.

The fluorine-containing random copolymer of the present invention is a random copolymer in which the monomer units represented by the general formulas (I), (II) and (III) are randomly arranged.

Since the fluorine-containing random copolymer of the present invention is insoluble in various solvents, its molecular weight cannot be determined by ordinary means. However, since the specific melt viscosity of the fluorine-containing random copolymer of the present invention depends on the molecular weight, the molecular weight can be estimated by measuring the specific melt viscosity. That is, the fluorine-containing random copolymer of the present invention has 3
Although the specific melt viscosity measured at 72 ° C. is in the range of 1 × 10 ² to 1 × 10 ⁷ poise, the range of 1 × 10 ³ to 1 × 10 ⁶ poise in consideration of the moldability of the fluorine-containing random copolymer. It is preferred that When the specific melt viscosity measured at 372 ° C. is out of the range of 1 × 10 ² to 1 × 10 ⁷ poise, the obtained copolymer has poor moldability and is difficult to use.

The fluorine-containing random copolymer of the present invention has a nuclear magnetic resonance spectrum of fluorine (hereinafter simply referred to as ¹⁹ F-NMR) and an infrared absorption spectrum (hereinafter simply referred to as IR).
Can be easily confirmed by measuring singly or in combination. ^In the measurement of ¹⁹ F-NMR, measurement is performed at 320 ° C., and trichlorofluoromethane is used as a reference substance (the high magnetic field side is negative and expressed in ppm). −
80 to -90 ppm CF ₃ group, -110 to -130 p
pm to CF ₂ group has a peak based on CF group -135~-140ppm, the integral value of these peaks, the formula of the fluorinated random copolymer (I)
A monomer unit based on tetrafluoroethylene, a monomer unit based on a short-chain fluorinated vinyl ether represented by the general formula (II), and a monomer unit based on the general formula (III)
The monomer unit ratio with the monomer unit based on the long-chain fluorine-containing vinyl ether represented by the formula (1) can be determined. FIG. 1 shows ¹⁹ F- of the fluorine-containing random copolymer obtained in Example 1.
3 shows an NMR chart.

Further, in the measurement of IR, 990c
It has an absorption band based on a> CFOCF ₂ — group near m ⁻¹ and a —CF ₂ — group near 1200 cm ⁻¹ , and 9
Around 50 cm ^-1 > CFOCH ₂ -group and 2975 cm
^-1 and has an absorption band based on a —CH ₂ — group, and the quantification of these absorption bands indicates that the fluorine-containing random copolymer has a simple structure based on tetrafluoroethylene represented by the above general formula (I). A monomer unit based on the short-chain fluorine-containing vinyl ether represented by the general formula (II);
The monomer unit ratio with the monomer unit based on the long-chain fluorine-containing vinyl ether represented by the general formula (III) can be determined. FIG. 2 shows an IR chart of the fluorine-containing random copolymer obtained in Example 1.

The fluorine-containing random copolymer of the present invention may be produced by any method. Preferably, tetrafluoroethylene and the general formula (IV)

[0032]

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(Where n and X ¹ are the same as described above) and a fluorine-containing vinyl ether represented by the general formula (V):

[0034]

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(Wherein m and X ² are the same as those described above) with the long-chain fluorinated vinyl ether containing 90 to 99 mol% of the above tetrafluoroethylene and the short-chain fluorinated vinyl ether. Together with 1 to 10 mol%, and the long-chain fluorinated vinyl ether occupying the total of the short-chain fluorinated vinyl ether and the long-chain fluorinated vinyl ether is randomly copolymerized at a copolymerization ratio of 40 to 99 mol%. Is preferred.

Here, the short-chain fluorine-containing vinyl ether represented by the above general formula (IV) is not particularly limited, but preferred examples thereof are as follows.

CF ₂ ＣＦCFOCH ₂ CF ₃ , CF ₂ ＣＦCFOCH ₂ CF ₂ H, CF ₂ ＣＨCFOCH ₂ CF ₂ Br, CF ₂ ＣＦCFOCH ₂ CF ₂ Cl, CF ₂ ＣＦCFOCH ₂ CF ₂ CF ₃ , CF _{2 = CFOCH 2 CF 2 CF 2 H} , CF 2 = CFOCH 2 CF 2 CF 2 Br, CF 2 = CFOCH 2 CF 2 CF 2 Cl, CF 2 = CFOCH 2 (CF 2) 2 CF 3, CF 2 = CFOCH 2 ( _{CF 2) 2 CF 2 H,} CF 2 = CFOCH 2 (CF 2) 2 CF 2 Br, CF 2 = CFOCH 2 (CF 2) 2 CF 2 Cl, and the like. Further, the long-chain fluorine-containing vinyl ether represented by the above general formula (V) is not particularly limited, but preferred examples thereof are as follows.

CF ₂ ＣＦCFOCH ₂ (CF ₂ ) ₄ CF ₃ , CF ₂ ＣＦCFOCH ₂ (CF ₂ ) ₄ CF ₂ H, CF ₂ ＣＦCFOCH ₂ (CF ₂ ) ₄ CF ₂ Br, CF ₂ ＣＦCFOCH ₂ ( _{CF 2) 4 CF 2 Cl,} CF 2 = CFOCH 2 (CF 2) 5 CF 3, CF 2 = CFOCH 2 (CF 2) 5 CF 2 H, CF 2 = CFOCH 2 (CF 2) 5 CF 2 Br, CF ₂ = CFOCH ₂ (CF ₂ ) ₅ CF ₂ Cl, CF ₂ = CFOCH ₂ (CF ₂ ) ₆ CF ₃ , CF ₂ = CFOCH ₂ (CF ₂ ) ₆ CF ₂ H, CF ₂ = CFOCH ₂ (CF ₂ ) _{6 CF 2 Br, CF 2 = CFOCH} 2 (CF 2) 6 CF 2 Cl, CF 2 = CFOCH 2 (CF 2) 7 CF 3, CF 2 = CFOCH 2 (CF 2) 7 CF 2 H, CF 2 = CFOCH 2 (CF ₂ ) ₇ CF ₂ Br, CF ₂ = CFOCH ₂ (CF ₂ ) ₇ CF ₂ CL, and the like. As a method of copolymerizing such tetrafluoroethylene and the fluorine-containing vinyl ether represented by the general formula (IV, V), a known method is used without any particular limitation. That is, an optimum polymerization method may be selected from among polymerization methods such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method in consideration of conditions such as copolymerizability of a monomer to be used.

First, the solution polymerization method will be described. The organic solvent used is not particularly limited, but chlorofluorocarbon, chlorofluorohydrocarbon and perfluorocarbon are generally preferably used. Also,
In the case of solution polymerization, 0.3-
It is also possible to carry out the polymerization in the presence of 10 times by weight, preferably 1 to 5 times by weight of water. As the polymerization initiator,
Known radical generators can be employed, but in consideration of the heat resistance of the obtained fluorine-containing random copolymer, fluorine-containing radical generators are preferred. For example, [D (CF ₂ ) _y CO ₂ ] ₂ (where D is a hydrogen atom, a fluorine atom, or a chlorine atom, and y is an integer of 1 to 5),

[0040]

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(Where D is a hydrogen atom, a fluorine atom or a chlorine atom, y is an integer of 1 to 5, and q is 0
-3. ) Is adopted. Furthermore, if specific examples of the radical generator suitably used in the present invention are shown,

[0042]

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And the like. The amount of the radical generator used cannot be determined unconditionally depending on the solvent used, the polymerization conditions, particularly the temperature, but is usually 0.002 to 0.5 mol%, preferably 0.005 mol%, based on the amount of the monomer used.
A range of 5 to 0.2 mol% may be selected. Further, the radical generator may be introduced at once at the start of the polymerization, or may be introduced intermittently during the polymerization. Particularly, depending on the conditions, the polymerization may be difficult to proceed on the way, but in such a case, it is effective to add the radical generator again in the middle.
The polymerization temperature is determined based on the decomposition rate of the radical generator to be used as one standard, and is usually 0 to 100 ° C, preferably 5 to 60 ° C.

In the suspension polymerization, the type and amount of the polymerization initiator can be carried out in the same manner as described for the solution polymerization. The polymerization temperature is determined using the decomposition temperature of the radical generator as one guide, but is usually 0 to 100 ° C.
Preferably it is 5-60 degreeC. In suspension polymerization, it is preferable to use a dispersion stabilizer. Known dispersion stabilizers may be used without any limitation, but ammonium perfluorocarboxylate, ammonium perfluorosulfonate, polyvinyl alcohol and the like are preferably used, and the effect of dispersion stability is particularly obtained. From the thermal stability of the copolymer, ammonium perfluorocarboxylate having a long-chain alkyl group having 5 to 10 carbon atoms is preferred. From the viewpoint of dispersion stability, chlorofluorocarbons and perfluoro compounds may be used in addition to the above-mentioned dispersion stabilizers, and the amount thereof is preferably 0.1 to 1 times the weight of water.

The emulsion polymerization will be further described. A water-soluble radical generator is used as a polymerization initiator.
Inorganic peroxides such as ammonium persulfate and potassium persulfate are preferably used. The polymerization temperature is from 20 to 140C, preferably from 40 to 100C. In the emulsion polymerization, a dispersion stabilizer may be used, and the type and amount thereof are as described in the suspension polymerization. In emulsion polymerization, a buffer such as ammonium carbonate may be used without any problem.

In any of the polymerization methods, the polymerization reaction proceeds sufficiently if the pressure of tetrafluoroethylene is in the range of 1 to 30 kg / cm ² -G. However, when the pressure is too high, the apparatus becomes considerably expensive. 1 to 1
0 kg / cm ² -G is preferred. A predetermined amount of tetrafluoroethylene and fluorinated vinyl ether may be sealed in a reactor to carry out the polymerization, and depending on the amount consumed by the polymerization of tetrafluoroethylene and fluorinated vinyl ether, only tetrafluoroethylene or tetrafluoroethylene may be used. Fluoroethylene and fluorinated vinyl ether may be added continuously or intermittently during polymerization.

Further, in any of the polymerization methods, it is preferable to add a chain transfer agent for controlling the molecular weight. Examples of the chain transfer agent include chlorinated hydrocarbons such as carbon tetrachloride and chloroform; alkanes such as hexane, pentane, butane, propane, ethane and methane; ethers such as diethyl ether and dimethyl ether; methanol and ethanol. Of these, alkanes, alcohols and hydrogen are preferred from the viewpoints of the solubility in the polymerization solvent and the stability of the produced copolymer. If the chain transfer agent is a gas, it may be injected at a pressure that can maintain a necessary amount of dissolution in the polymerization solvent. In the case of a liquid, the necessary amount may be added in advance or intermittently. The amount of chain transfer agent used depends on the type of chain transfer agent,
Although it varies within a certain range depending on the polymerization conditions, it is usually preferably from 0.05 to 10 mol%, preferably from 0.1 to 5 mol%, based on the total amount of monomers in the polymerization tank. Here, when water is present in the polymerization system, it is preferable to add the chain transfer agent so that the concentration of the chain transfer agent in the organic phase is within the above range in consideration of the distribution ratio between the aqueous phase and the organic phase.

The produced fluorine-containing random copolymer is obtained by separating unreacted monomers, solvents and the like from the polymerization reaction mixture. For the operation, a known monomer removing method can be adopted. For example, the operation of releasing gaseous tetrafluoroethylene from the gas phase of the polymerization tank, the filtration of unreacted tetrafluoroethylene and unreacted fluorinated vinyl ether dissolved in the polymerization solvent, centrifugation, and heating or depressurization are performed to obtain a fluorine-containing random copolymer. An operation of separating from the polymer can be given.

In the fluorine-containing random copolymer of the present invention, X ¹ , a monomer unit based on the fluorine-containing vinyl ether represented by the general formulas (II) and (III),
A copolymer in which any of X ² is not a fluorine atom can be easily perfluorinated with a fluorinating agent such as fluorine gas.

Since the fluorine-containing random copolymer of the present invention has excellent chemical resistance, it can be used as a film, a tube, a packing material, a lining material, a wafer carrier, a bottle, and other molded products in industrial fields requiring chemical resistance. Can be used. It also has excellent electrical properties, especially dielectric constant,
Because of its low dielectric loss, it can be used for connectors, substrate materials, insulating materials, etc. in the electric and electronics fields. Further, since it has excellent mechanical strength, particularly excellent bending life, it is also effective as a wire coating agent.

[0051]

The fluorine-containing random copolymer of the present invention comprises a monomer unit based on tetrafluoroethylene represented by the general formula (I) and a specific short unit represented by the general formulas (II) and (III). Since the monomer units based on the long-chain fluorinated vinyl ether and the monomer units based on the long-chain fluorinated vinyl ether are copolymerized at a specific composition ratio, the tensile breaking strength and the bending life resistance are reduced. All of the mechanical strengths are remarkably excellent. This value is, for example, that the monomer unit based on tetrafluoroethylene represented by the general formula (I) and the monomer unit based on the short-chain fluorinated vinyl ether represented by the general formula (II) are the same. In the case of the same specific melt viscosity, the tensile strength at break is about 40 to 60 kg / cm ² higher and the bending life is about 2 to 5 times higher than that of the polymerized binary copolymer. A binary copolymer of a monomer unit based on tetrafluoroethylene represented by the general formula (I) and a monomer unit based on a long-chain fluorine-containing vinyl ether represented by the general formula (III) Compared to the copolymer, when the specific melt viscosity is the same, it has an equally good bending life and a tensile breaking strength of 160 to 180 k.
g / cm ² higher.

[0052]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

The measured values were obtained as follows.

1. Tensile breaking strength (1) Measurement Measured according to JIS K7113.

(2) Preparation of Test Samples The fluorine-containing random copolymer of the present invention and a copolymer for comparison were melted at a temperature of 350 ° C., and then cooled while compressing under a pressure of 120 kg / cm ^2. A sheet having a thickness of ２2 mm was prepared.

2. Specific Melt Viscosity Measured using a Koka type melt viscosity measuring device (manufactured by Shimadzu Corporation). Using a die having a diameter of 1 mm and a length of 10 mm, measurement was performed at a temperature of 372 ° C. with a load of 13.14 kg.

3. Bending Life (1) Measurement Bending life was measured using a standard bending durability tester described in ASTM D-2176-63T. For the measurement, a film having a length of 120 mm and a width of 15 mm was attached to a standard bending durability tester, and a load of 1.25 kg was applied. The film is moved left and right by a standard bending durability tester.
Fold at a rate of about 175 cycles / min at 35 degree angles. The number of cycles to breakage was recorded on the counter of a standard bending endurance tester, and each sample was measured three times.
The average value was defined as the bending life.

(2) Preparation of Test Sample The fluorine-containing random copolymer of the present invention and a copolymer for comparison were melted at a temperature of 340 ° C., then cooled while compressing at a pressure of 120 kg / cm ² , and cooled to 0%. A film having a thickness of 0.2 to 0.23 mm was prepared.

Example 1 400 g of 1,1,2-trichlorotrifluoroethane purified by distillation was put into a 300-mL stainless steel reactor equipped with a stirrer, and the inside was degassed. Atmospheric pressure. In the reactor, 0.14 g of methanol and 3.22 g of 2,2,3,3,3-pentafluoropropyltrifluorovinyl ether and 2,2,3,3,4,4,5,5,6, 6,
After adding 6,72 g of 7,7,7-pentadecafluorooctyl trifluorovinyl ether, the rotation speed of the stirring motor was set to 800, and tetrafluoroethylene was introduced to adjust the pressure to 8 kg / cm ² -G. Next, 18
While maintaining the temperature at ° C, 1.1 g of a 1,1,2-trichlorotrifluoroethane solution (5% by weight) of bis (heptafluorobutyryl) peroxide was introduced to initiate polymerization. During the polymerization, the polymerization temperature was kept at 18 ° C. and the pressure was kept at 8 kg / cm ² -G by introducing tetrafluoroethylene. 100 minutes after the start of the reaction, the amount of tetrafluoroethylene introduced is 4
When the pressure reached 0 g, the pressure in the reactor was released.
The reactor was connected to a vacuum pump via a cooling trap, and the pressure was reduced while stirring, and low boiling components such as a solvent and unreacted monomers were collected in the trap. After the distillation, the reactor was disassembled, the copolymer was taken out, and vacuum-dried at 150 ° C. for 12 hours to obtain 46 g of the copolymer.

When ¹⁹ F-NMR of this copolymer was measured, a peak derived from a monomer unit based on CF ₂ ＝ CFOCH ₂ C ₂ F ₅ was −87.6 ppm (3F) -121.9. ppm (2F) -138.0 ppm (1F), a peak derived from a monomer unit based on CF ₂ ＣＦCFOCH ₂ C ₇ F ₁₅ was −84.3 ppm (3F) −122.1 ppm (2F ) Was confirmed at -137.9 ppm (1F) (FIG. 1). When the IR of this copolymer was measured, a peak derived from a monomer unit based on CF ₂ = CFOCH ₂ C ₂ F ₅ was found to be 2975 cm ⁻¹ (—CH ₂ −) 935 cm ⁻¹ (> In CFOCH ₂ −), a peak derived from a monomer unit based on CF ₂ ＣＦCFOCH ₂ C ₇ F ₁₅ was confirmed at 2975 cm ⁻¹ (—CH ₂ −) 955 cm ⁻¹ (> CFOCH ₂ −). (FIG. 2). From the above results, the copolymer was found to have 9 monomer units based on tetrafluoroethylene.
7.27 mol%, a monomer unit based on 2,2,3,3,3-pentafluoropropyl trifluorovinyl ether is 1.0
Mol%, 2,73,3,3,4,4,5,5,6,6,7,7,7-pentadecafluorooctyl trifluorovinyl ether copolymerized 1.73 mol% of monomer units Was confirmed. Further, the specific melt viscosity at 372 ° C. of the copolymer was 2.4 × 10 ⁵ poise.

This copolymer was melt-molded and subjected to JIS K-
When the tensile strength at break was measured based on No. 7113, it was 5
It was 50 kg / cm ² . Furthermore, the bending life was measured to be 3540100 times.

Examples 2 to 7, Comparative Examples 1 and 2 In Example 1, the amount of the fluorine-containing vinyl ether charged,
Copolymerization was performed in the same manner as in Example 1 except that the amounts of methanol and radical initiator charged were changed to the conditions shown in Table 1, to obtain a copolymer. About the obtained copolymer,
As a result of IR measurement, the content of the monomer unit based on the fluorinated vinyl ether in the copolymer is shown in Table 1. Table 2 shows the results of measuring the specific melt viscosity, tensile strength at break, and bending life of the copolymer.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

Examples 8 to 17 In Example 1, the kind of fluorine-containing vinyl ether, the amount of fluorine-containing vinyl ether charged, the amount of methanol charged,
Copolymerization was carried out in the same manner as in Example 1 except that the charged amount of the radical initiator was changed to the conditions shown in Tables 3 and 5, to obtain a copolymer. Table 3 and Table 5 show the content of monomer units based on the fluorinated vinyl ether in the copolymer as a result of IR measurement of the obtained copolymer. Also,
Tables 4 and 6 show the results of measuring the specific melt viscosity, tensile strength at break, and bending life of the copolymer.

[0067]

[Table 4]

[0068]

[Table 5]

[0069]

[Table 6]

[0070]

[Table 7]

[0071]

[Table 8]

[Brief description of the drawings]

FIG. 1 is a ¹⁹ F-NMR chart of the fluorine-containing random copolymer of the present invention obtained in Example 1.

FIG. 2 is an IR chart of the fluorine-containing random copolymer of the present invention obtained in Example 1.

Claims (1)

(57) [Claims] (A) General formula (I) And (B) i) a monomer unit based on tetrafluoroethylene represented by the following formula: (Where n is an integer of 1 to 3 and X ¹ is a hydrogen atom or a halogen atom); and ii) a monomer unit based on a short-chain fluorinated vinyl ether represented by the general formula (III): 3] (Where m is an integer of 5 to 20, and X ² is a hydrogen atom or a halogen atom). 372 to 372 mol% of the monomer units based on the long-chain fluorinated vinyl ether in the total of the monomer units based on the short-chain fluorinated vinyl ether and the monomer units based on the long-chain fluorinated vinyl ether; A fluorine-containing random copolymer having a specific melt viscosity of 1 × 10 ² to 1 × 10 ⁷ poise measured at ° C.