JP2000319471A - Polymer composition and molded product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer composition which has such crystallization properties as to form small spherulites without detriment to moldability by compounding a fluorocopolymer prepared by thermally treating a copolymer comprising specific kinds of structural units in a specified ratio at a specified temperature or higher with a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer. SOLUTION: This composition comprises 80-99.95 pts.wt. fluorocopolymer and 20-0.05 pts.wt. tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer. The fluorocopolymer is prepared by thermally treating a copolymer comprising 96-99.99 mol% structural units represented by formula I, 0.01-1 mol% structural units represented by formula II and 0-3 mol% structural units represented by formula III at 200 deg.C or higher. The composition is melt molded to give a molded article having a spherulite size of 10 μm or lower. In the formulas, X is F or Cl; R1 is a divalent fluorinated organic group; Y is hydroxyl or the like; and Z is a monovalent fluorinated organic group other than-O-R1Y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in the crystallization characteristics of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (hereinafter referred to as PFA).

[0002]

2. Description of the Related Art PFA is a polymer material excellent in heat resistance, chemical resistance, solvent resistance and the like, and is used for various purposes by utilizing its characteristics. However, PFA is a crystalline resin, and a large number of crystal nuclei are generated in the melt during cooling and solidification after melt molding. Spherulites grow in the same direction around the crystal nuclei, and stop growing at the borders with each other. It is known that the surface smoothness of a molded product in which spherulites are formed depends on the size of the spherulites. If the spherulites grow large and the surface smoothness of the molded product is poor, impurities tend to accumulate on the surface when used as a tube. When used as a pipe joint, stress cracks are likely to occur.

[0003] It is known that the size of spherulites depends on the cooling rate after melt molding. Fine spherulites are generated as the quenching is performed, but quenching may not be possible depending on the molding method. For example, in the extrusion molding of a thick-walled tube, when the extruded tube is cooled from the outer surface, the inner surface of the pipe is not quenched, so that large spherulites are generated on the inner surface of the pipe, and the smoothness of the inner surface is poor. There is a need for PFA having crystallization characteristics that generate fine spherulites even at a relatively slow cooling rate.

[0004] As a method of refining spherulites of PFA,
There is known a method of adding a small amount of a specific polytetrafluoroethylene (hereinafter referred to as PTFE) as a crystal nucleating agent to PFA (JP-A-7-70397). But PT
When the melt-kneading of FE and PFA is insufficient, fish eyes tend to occur. In addition, PTFE can be melted and kneaded excessively.
Is mixed with PFA, and there is a problem that the effect of refining spherulites as a crystal nucleating agent is reduced.

[0005]

An object of the present invention is to provide a PF
An object of the present invention is to improve the crystallization characteristics so that small spherulites are formed without impairing the physical properties and moldability of A.

[0006]

According to the present invention, the unit represented by the formula 1 is 96 to 99.99 mol%, the unit represented by the formula 2 is 0.01 to 1 mol%, and the unit represented by the formula The copolymer (A) containing the unit represented by 3 in a ratio of 0 to 3 mol% (hereinafter referred to as a fluorine-containing copolymer (A)) is 20
Fluorinated copolymer (B) heat-treated at 0 ° C. or higher, PF
A (C) and a fluorine-containing polymer composition containing 0.05 to 20 parts by weight of (B) based on 100 parts by weight of the total of (B) and (C). provide.

[0007]

Embedded image

Wherein X is a fluorine atom or a chlorine atom; R ^f is a divalent fluorine-substituted organic group;
Is a hydroxyalkyl group, a carboxyl group, or a monovalent carboxylic acid derivative group, and Z is a monovalent fluorine-substituted organic group other than —O—R ^f Y.

Further, the present invention provides a molded product obtained by melt-molding the above-mentioned fluoropolymer composition.

The fluorinated copolymer (B) is obtained by subjecting the fluorinated copolymer (A) to a heat treatment.
It functions as a crystal nucleating agent of (C). Even if the fluorine-containing polymer composition of the present invention is excessively melt-kneaded, the effect as a crystal nucleating agent does not decrease.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention is a composition containing a fluorine-containing copolymer (B) and PFA. Heat treatment of the fluorinated copolymer (A) increases the melt viscosity of the fluorinated copolymer (B) obtained. This is because, by heat treatment, the compound of formula 2 in the molecule of the fluorocopolymer (A)
Functional group -O-R ^f Y unit, by crosslinking reaction with the functional base in the other molecule, the fluorine-containing copolymer (B) is estimated to be due to generated having a crosslinked structure in the.
However, this description is to help the understanding of the present invention, and does not limit the present invention in any way.

The fluorine-containing copolymer (B) in the composition of the present invention can be a PFA crystal nucleating agent. When a small amount of the fluorinated copolymer (B) is added to PFA, melt-kneaded and molded, fine spherulites are formed in the molded product. Also, unlike PTFE, even if it is excessively melt-kneaded, the effect as a crystal nucleating agent is not impaired. This effect is presumably because the fluorine-containing copolymer (B) is not completely mixed with PFA due to crosslinking.

In the unit of the formula 1, X is preferably a fluorine atom from the viewpoint of chemical resistance and the like. In the unit of Formula 2, R ^f, that is, the divalent fluorine-substituted organic group is
It is sufficient that the number of substituted fluorine atoms is one or more, and a fully fluorinated divalent fluorine-substituted organic group is more preferable. R ^f is preferably a carbon-only or divalent fluorine-substituted organic group having a chain formed by carbon and oxygen.

Specific examples thereof include a perfluoroalkylene group or a perfluoroalkylene group containing an ether bond. The number of carbon atoms constituting the chain of R ^f is preferably in the range of 1 to 15, particularly 1 to 10. R ^f preferably has a linear structure, but may have a branched structure.
In the case of a branched structure, the number of carbon atoms in the branched portion is 1 to 3.
Those having a short chain of the order are preferred. Particularly preferred R ^f - a (m is an integer of from 2 to 6) - (CF _{2) m.}

R^fIs, for example,-(CF_Two)
_Two−, − (CF_Two)_Three−, − (CF_Two) _Four−, − (CF_Two)_Five
−, − (CF_Two)₆-, -CF_TwoCF (CF_Three) O (C
F_Two)_Three-, -CF_TwoCF (CF_Three) OCF_TwoCF (CF_Three)
O (CF_Two)_Two−, − (CF_TwoCF_TwoO)_Two− (CF_Two)
_Three−, −CF_TwoCF (CF_Three) CF_TwoCF_TwoCF (CF_Three) C
F_Two-And the like.

In formula 2, Y is a hydroxyalkyl group,
A carboxyl group or a monovalent carboxylic acid derivative group
You. As the carboxylic acid derivative group, -COOA (A is carbon
Alkyl group of about 1 to 3 and fluor of about 1 to 3 carbon atoms
Alkyl groups, alkali metals, ammonium bases,
Is a substituted ammonium base) or -COB (B is fluorine
Atom or chlorine atom). Of these,
Preferably, Y is a hydroxyalkyl group or an alkoxy group.
A rubonyl group, -CH_TwoOH, -CH_TwoCH _TwoOH,
-COOCH_ThreeIs preferred.

The content of the unit represented by the formula 2 in the fluorinated copolymer (A) is from 0.01 to 1 mol%. 0.0
If it is less than 1 mol%, the crosslink density of the fluorine-containing copolymer (B) is insufficient, and if it is melt-kneaded with PFA excessively, it is mixed with PFA and has little effect as a crystal nucleating agent. If it exceeds 1 mol%, the melt viscosity of the fluorinated copolymer (B) becomes too high, and PF
It becomes difficult to knead with A and fish eyes are generated. Equation 2
May be included alone or in combination of two or more.

In the unit of the formula 3, Z, that is, a monovalent
The nitrogen-substituted organic group is represented by the formula -OR ^fMonovalent other than Y
It is a nitrogen-substituted organic group.
A perfluoroalkoxy group having 1 to 10 carbon atoms is preferred.
No. When the content of the formula 3 exceeds 3 mol%, the fluorine-containing copolymer
The melting point of (B) is too low, and its effect as a crystal nucleating agent is low.
Become.

The fluorinated copolymer (B) can be obtained by subjecting the fluorinated polymer (A) to a heat treatment at a temperature of 200 ° C. or higher. When the temperature is lower than 200 ° C., —OR ^f Y in Formula 2 is hard to undergo a crosslinking reaction. Although -O-R ^f Y is a melting point or higher to crosslinking reaction, for fluoropolymer (B) is fused, so unless added to the PFA by grinding it may cause fish eyes, preferably the melting point It is preferred to employ a heat treatment temperature of less than. The heat treatment is preferably carried out for a time until 50% or more, preferably 90% or more of Y in the formula 2 decomposes and undergoes a crosslinking reaction. If a large amount of Y in Formula 2 remains without a crosslinking reaction, the chemical resistance of the composition may be reduced.
The heat treatment time is preferably 3 hours or more at 300 ° C., for example. The heat treatment in the present invention is desirably performed in an atmosphere in which oxygen is present.

The mechanism presumed to have a crosslinked structure in the fluorinated copolymer (B) is shown below. In the fluorinated copolymer (A), Y in Formula 2 is recognized by IR analysis. In the fluorinated copolymer (B), it is recognized that the amount of Y is reduced as compared with the fluorinated copolymer (A), or Y is not recognized. Further, the melt viscosity of the fluorinated copolymer (B) is larger than that of the fluorinated copolymer (A), and the rate of increase is determined by the content ratio of Y in Formula 2 in the fluorinated copolymer (A). The greater the number, the greater.

For example, in formula 2, -R ^f Y is-(CF ₂ ) ₃
COOCH ₃ , and the unit represented by the formula 2 is 0.2
Mol%, containing 99.8 mol% of a unit represented by the formula 1,
The fluorinated copolymer (A) obtained by heat-treating the fluorinated copolymer (A) having a melt viscosity of 7.7 × 10 ⁴ poises at 300 ° C. for 20 hours has -COOCH ₃ -derived by IR analysis. No peak was detected and its melt viscosity was 1.6 × 10
Rises to ⁶ poise.

As a mechanism for forming a crosslinked structure, Y, for example, —COOCH ₃ causes a hydrolysis reaction, a decarboxylation reaction, and the like by heat and moisture in the air to generate —CF ₂ CF ₂ .radicals. It is presumed that two radicals between the merging chains are coupled to form a crosslinked structure. Therefore, the fluorine-containing copolymer (B) is a modified polymer containing a polymerized unit based on tetrafluoroethylene homopolymer (PTFE), a trace amount of hexafluoropropylene less than 1% by weight, perfluoro (alkyl vinyl ether) or the like.
It is presumed to have a structure different from FE.

The heat of crystallization of the fluorine-containing copolymer (B) is preferably from 40 to 49 J / g. When a crosslinked structure is generated by the heat treatment, the crystallinity tends to decrease and the heat of crystallization tends to decrease. If the heat of crystallization exceeds 49 J / g, the crosslink density of the fluorine-containing copolymer (B) is insufficient, and if it is excessively kneaded with PFA, the effect as a crystal nucleating agent is reduced. On the other hand, if it is less than 40 J / g, the crosslink density becomes too high and PFA
And it becomes difficult to mix with it, causing fish eye.

The proportion of the fluorine-containing copolymer (B) in the composition of the present invention is 0.05 to 20 parts by weight based on 100 parts by weight of the total of PFA and the fluorine-containing copolymer (B). If the amount is less than 0.05 part by weight, the effect of refining the spherulites is small, and if it exceeds 20 parts by weight, the moldability tends to be impaired.

The fluorinated copolymer (A) and its production method are known (JP-A-3-91513, JP-A-3-2313).
34753). The fluorinated copolymer (A) is obtained by reacting a monomer represented by the formula 4, a monomer represented by the formula 5, and optionally a monomer represented by the formula 6 under the action of a polymerization initiation source. It is obtained by copolymerization. However, X in Formula 4, ^Rf and Y in Formula 5, and Z in Formula 6 are all the same as described above.

[0026]

Embedded image

As a polymerization initiation source, ionizing radiation, a polymerization initiator such as an organic peroxide-based polymerization initiator or an oxidation-reduction-based polymerization initiator can be employed. As the polymerization method, a conventionally known polymerization method such as suspension polymerization, emulsion polymerization, solution polymerization, or bulk polymerization can be employed.

Examples of the polymerization initiator include bis (fluoroacyl) peroxides, bis (chlorofluoroacyl) peroxides, dialkylperoxydicarbonates, diacyl peroxides, peroxyesters,
And persulfates.

As a polymerization medium, CCIF is used in solution polymerization.
_TwoCF_TwoCCIFH (hereinafter referred to as HCFC225cb)
Which hydrochlorofluorocarbons, t-buta
In suspension polymerization and emulsion polymerization, water or water is used.
Is a mixed solvent of water and another solvent. The polymerization temperature is
0 ° C to 100 ° C, polymerization pressure 0.5 to 30 kg / cm ^Two
Can be selected from the range.

The perfluoro (alkyl vinyl ether) which is a raw material monomer of PFA in the present invention includes P
From the viewpoint of the mechanical strength of FA at high temperatures, the number of carbon atoms is 3 to
A perfluoro (alkyl vinyl ether) having 10 is preferred, and a perfluoro (propyl vinyl ether) having 5 carbon atoms is particularly preferred. Further, the content ratio of the polymerization unit based on perfluoro (alkyl vinyl ether) in PFA is preferably about 1 to 3 mol% from the viewpoint of the moldability of PFA and the mechanical strength at high temperature.

Although the melt viscosity of PFA is not particularly limited, the melt viscosity at 372 ° C. is 5 × from the viewpoint of moldability.
It is preferably 10 ^{3 to} 5 × 10 ⁵ poise. The fluoropolymer composition of the present invention has crystallization characteristics with a small spherulite size without impairing the excellent physical properties and moldability of PFA.

The method for melt-kneading the fluoropolymer composition is not particularly limited. A method in which the fluorine-containing copolymer (B) is mixed with the molten PFA while stirring, a method in which the PFA and the fluorine-containing copolymer (B) are simultaneously supplied to a single-screw or twin-screw extruder and kneaded. Can be For convenience, a method of kneading with a kneading extruder is preferred. PF during kneading
The form of A and the fluorinated copolymer (B) is also not particularly limited, and pellets, beads, powders and the like are used, but the form of the fluorinated copolymer (B) is preferably powder.

The fluoropolymer composition of the present invention can be melt-molded. Melt molding refers to molding a molded product such as a film, a sheet, a tube, or the like from a molten fluoropolymer composition using an extruder, an injection molding machine, or a compression molding machine. This includes molding a molded article coated on a substrate.

The fluorinated polymer composition of the present invention has a fluorinated polymer having a spherulite size of 10 μm or less by melt molding.
Preferably, a molded article having a size of 5 μm or less is provided, and an extruded tube having an inner surface roughness of 0.3 μm or less is provided. Furthermore, since it has crystallization characteristics that easily generate fine spherulites even at a relatively slow cooling rate, it is possible to smoothly and advantageously obtain a tube with excellent inner surface smoothness even when forming a thick tube by an extrusion method. it can.

In the present invention, spherulite size, inner surface roughness,
Melt viscosity, melting point, heat of crystallization, crystallization temperature, and copolymer composition are measured by the following methods.

[Spherulite Size]
A test film is prepared by compression molding into a μm film, and then rapidly cooling it to around room temperature in about 5 minutes using a cooling press machine. Spherulite size was measured by observing the surface of the test film with a polarizing microscope.

[Inner Surface Roughness] Using a single-screw extruder, 3
Extrusion molding is performed at 80 ° C. into a tube having an inner diameter of 8 mm and an outer diameter of 10 mm, followed by water cooling from the outside of the tube to prepare a test tube. The inner surface roughness (R _t ) of the test tube was measured with a roughness meter (Surfcoder SE-30H, manufactured by Kosaka Laboratories).

[Melt Viscosity] Using a flow tester manufactured by Shimadzu Corporation, using a die having a nozzle length of 8 mm and a nozzle diameter of 2.1 mm, a load of 7 kg and a flow value Q (cm ³ / sec) when extruded at a predetermined temperature. , Melt viscosity (Poise) = 409 /
It was determined by the equation Q.

[Melting Point] A 10 mg sample was measured using DTA (manufactured by Seiko Denshi) at a heating rate of 10 ° C./min, and the temperature at the end of the endothermic peak was defined as the melting point.

[Heat of crystallization, crystallization temperature]
Using a SC (manufactured by Seiko Denshi), 10 ° C from the molten state
The crystallization heat at the time of cooling at a rate of / min and crystallization and its peak temperature were measured. The peak temperature was taken as the crystallization temperature.

[Copolymer Composition] A molded film having a thickness of about 30 μm was subjected to IR analysis and determined as follows. (CF ₂ = CF
O (CF ₂ ) ₃ COOCH ₃ polymerized unit / (tetrafluoroethylene-based polymerized unit) (molar ratio) is 0.42 × (absorbance at 2370 cm ⁻¹ ) / (18
(Absorbance at 00 cm ^-1 ).

[0042]

[Example 1] A stainless steel reaction vessel having an inner volume of 1.1 liter was degassed, and 470 g of water and HCFC225c were used.
290 g of b, 10.5 g of CF ₂ ＣＦCFO (CF ₂ ) ₃ COOCH ₃ , 80 g of tetrafluoroethylene (hereinafter referred to as TFE), and 45 g of methanol were charged. While maintaining the temperature at 50 ° C., the concentration of the polymerization initiator bis (perfluorobutyryl) peroxide was 0.25% by weight of HCF.
A C225cb solution was charged and the reaction was started. During the reaction, TFE was introduced into the system, and the reaction pressure was increased to 13.0 kg /
cm ² . The polymerization initiator was intermittently charged so that the polymerization rate was almost constant. 100 TFE introduced
g, the reaction is terminated and the fluorine-containing copolymer A
106 g of the white powder of 1 were obtained. As a result of NMR analysis, the fluorinated copolymer A1 was found to be CF ₂ ＣＦCFO (CF ₂ ) ₃ COO
The content of polymerized units based on CH ₃ is 0.4 mol%, the melting point is 315 ° C., the crystallization temperature is 295 ° C., and the heat of crystallization is 51 J.
/ G at 372 ° C. and a melt viscosity of 7.8 × 10 ⁴ poise.

Subsequently, the fluorinated copolymer A1 was heated at 300 ° C.
Heat treatment in an oven for 24 hours to obtain a fluorine-containing copolymer B1
I got As a result of IR analysis, the fluorine-containing copolymer B1 contained-
No peak derived from COOCH ₃ was detected, and the melting point was 3
20 ° C., crystallization temperature 302 ° C., heat of crystallization 43 J /
g, and the melt viscosity at 372 ° C. was 5.3 × 10 ⁶ poise.

Next, polymerized units based on TFE / CF_Two
= CFOC_ThreeF₇98.7 / 1.3
(Molar ratio), and the melt viscosity at 372 ° C. is 2.5
× 10 ^FivePoise, PFA1 with crystallization temperature of 280 ° C
Using 95 parts by weight of the beads of PFA1 and the above
5 parts by weight of the powder of the fluorine-containing copolymer B1
Melt-kneading with a kneading extruder to obtain a fluoropolymer composition 1
Was obtained. The melt-kneading condition is the cylinder temperature C1.
/ C2 / C3 / C4 / C5 / C6 / H = 200 ° C / 35
0 ° C / 380 ° C / 380 ° C / 380 ° C / 385 ° C / 38
5 ° C, feed rate 20 kg / hr, screw rotation speed 80
rpm. The resulting pellet at 372 ° C.
The melt viscosity is 2.7 × 10^FivePoise.

The pellets of the fluoropolymer composition 1 were compression molded to obtain a film having a thickness of 200 μm. The spherulite size in this film was 1-3 μm. The inner surface roughness (R _t ) of the extruded tube obtained from the fluoropolymer composition 1 was 0.3 μm.

The melting and kneading conditions include a cylinder temperature C1 /
C2 / C3 / C4 / C5 / C6 / H = 200 ° C./390
° C / 390 ° C / 390 ° C / 390 ° C / 395 ° C / 395
C, spherulite size, inner surface roughness of extruded tube (R _t )
Was the same.

[Example 2] CF_Two= CFO (CF_Two)_ThreeCOO
CH_Three0.8 g of methanol and 50 g of methanol
Polymerization was carried out in the same manner as in Example 1, and the fluorinated copolymer A2 was white.
105 g of a powder were obtained. As a result of NMR analysis,
The polymer A2 is CF_Two= CFO (CF_Two) _ThreeCOOCH_ThreeTo
Content of polymerized units based on 0.09 mol% and melting point of 32
5 ° C, crystallization temperature 309 ° C, heat of crystallization 53.7 J /
g, melt viscosity at 372 ° C. is 9.7 × 10^FourPoise
Met. Fluorine-containing copolymer A2 at 300 ° C. for 24 hours
After heat treatment, the obtained fluorinated copolymer B2 was analyzed by IR.
As a result, -COOCH_ThreePeaks derived from
327 ° C, crystallization temperature 315 ° C, heat of crystallization
Is 47 J / g and the melt viscosity at 372 ° C. is 1.6 × 1
0^FivePoise.

5 parts by weight of the fluorinated copolymer B2 and 95 parts by weight of the beads of PFA1 used in Example 1 were melt-kneaded by a twin-screw kneading extruder to obtain a fluorinated polymer composition 2
Was obtained. The melt-kneading condition is the cylinder temperature C1.
/ C2 / C3 / C4 / C5 / C6 / H = 200 ° C / 35
0 ° C / 380 ° C / 380 ° C / 380 ° C / 385 ° C / 38
5 ° C, feed rate 20 kg / hr, screw rotation speed 80
rpm. The melt viscosity of the obtained pellet at 372 ° C. was 2.8 × 10 ⁵ poise.

The pellets of the fluoropolymer composition 2 were compression molded to obtain a 200 μm thick film. The spherulite size in this film was 1-3 μm. The inner surface roughness (R _t ) of the extruded tube obtained from the fluoropolymer composition 2 was 0.3 μm.

The melting and kneading conditions include a cylinder temperature C1 /
C2 / C3 / C4 / C5 / C6 / H = 200 ° C./390
° C / 390 ° C / 390 ° C / 390 ° C / 395 ° C / 395
C, spherulite size, inner surface roughness of extruded tube (R _t )
Was the same.

Example 3 (Comparative Example) CF ₂ ＣＦCFO (C
F _{2) 3} without using COOCH _3, except using 20g of methanol in the same manner as in Example 1 by polymerizing TFE, white PT
105 g of FE powder were obtained. This PTFE powder had a crystallization temperature of 315 ° C., a heat of crystallization of 55 J / g, and a melt viscosity at 372 ° C. of 1.7 × 10 ⁶ poise.

5 parts by weight of this PTFE powder and 95 parts by weight of the beads of PFA1 used in Example 1 were melt-kneaded by a twin-screw kneading extruder to obtain a pellet-shaped polymer composition. Melt kneading conditions are as follows: cylinder temperature C1 / C2 / C3
/ C4 / C5 / C6 / H = 200 ° C / 350 ° C / 380
° C / 380 ° C / 380 ° C / 385 ° C / 385 ° C, feed rate 20 kg / hr, screw rotation speed 80 rpm. The melt viscosity of the obtained pellet at 372 ° C. was 2.8 × 10 ⁵ poise.

The pellets of the polymer composition were compression molded to obtain a 200 μm thick film. The spherulite size in this film was 2-5 μm. The inner surface roughness (R _t ) of the extruded tube obtained from the polymer composition was 0.4 μm.

The melting and kneading conditions include a cylinder temperature C1 /
C2 / C3 / C4 / C5 / C6 / H = 200 ° C./390
° C / 390 ° C / 390 ° C / 390 ° C / 395 ° C / 395
When the temperature was changed to an excessive temperature of 10 ° C. and the feed rate was 10 kg / hr, the spherulite size increased to 10 to 20 μm, and the inner surface roughness (R _t ) of the extruded tube increased to 0.9 μm.

[0055]

According to the present invention, a PFA composition which produces fine spherulites in melt molding can be easily obtained without impairing the physical properties and workability of PFA, and a molded article having excellent surface smoothness can be obtained. Further, even under excessive melt-kneading conditions, the effect of refining spherulites does not decrease, and no decrease in surface smoothness is observed.

Claims (4)

[Claims] 1. A unit represented by the formula (1) is 96 to 99.99 mol%, a unit represented by the formula (2) is 0.01 to 1 mol%, and a unit represented by the formula (3) is defined as 0 as an optional component. Fluorinated copolymer (B) obtained by heat-treating copolymer (A) containing at a rate of ３3 mol% at 200 ° C. or more, and tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer (C) A composition comprising (B) and (C) in a total of 1
A fluoropolymer composition containing 0.05 to 20 parts by weight of (B) based on 00 parts by weight. Embedded image However, in the formula, X is a fluorine atom or a chlorine atom,
R ^f is a divalent fluorine-substituted organic group, Y is a hydroxyalkyl group, a carboxyl group, or a monovalent carboxylic acid derivative group, and Z is a monovalent fluorine-substituted organic group other than —O—R ^f Y It is. 2. Perfluoro (alkyl vinyl ether)
Is a perfluoro (propyl vinyl ether). 3. A molded article obtained by melt-molding the fluoropolymer composition according to claim 1 or 2. 4. The fluorinated polymer constituting the molded product has a spherulite size of 10 μm or less.
The molded article according to the above.