Composition, molded body, insulated wire, and method for manufacturing the composition

Abstract

The present invention provides a composition, etc., that can produce a molded article with excellent surface smoothness. [Solution] A composition comprising a copolymer containing TFE units and PAVE units, wherein the content of TFE units is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, the content of PAVE units is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer, the MFR is 1.0 to 40.0 g / 10 min, and in the melting curve observed by raising the temperature of the composition from 200°C to 350°C at 10°C / min using a differential scanning calorimeter, the ratio A of the peak area determined from the curve and line between 315°C and 330°C in the melting curve to the peak area indicating the heat of fusion is 1% to 20%, and the slope of the line connecting the heat flow at 315°C and the heat flow at 320°C is a positive value.

Description

[Technical Field]

[0001] This disclosure relates to compositions, molded articles, insulated wires, and methods for manufacturing compositions. [Background technology]

[0002] A copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PFA") is known as a fluororesin that has excellent mechanical, chemical, and electrical properties and can be melt-processed. PFA also has excellent heat resistance, chemical resistance, and purity.

[0003] For example, Patent Document 1 describes a melt-mold tetrafluoroethylene / fluoroalkoxytrifluoroethylene copolymer composition characterized by containing polytetrafluoroethylene having a crystallization temperature of 305°C or higher and a heat of crystallization of 50 J / g or higher. Non-patent document 1 describes adding polytetrafluoroethylene (hereinafter also referred to as "PTFE") as a nucleating agent to the molding material to refine the spherulites. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-70397 [Non-patent literature]

[0005] [Non-Patent Document 1] Netsu Sokutei, 38(3), pp. 77-82 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the field of semiconductor manufacturing, the threshold size for what is considered a pattern defect is decreasing as integrated circuits become smaller and more integrated. One of the causes of defects is the contamination of chemicals with metal ions from the chemical supply system of semiconductor manufacturing equipment. PFA molded bodies attached to the chemical supply system are also one of the sources of metal ions. One of the causes of metal contamination of PFA molded bodies is the presence of irregularities on the surface of the PFA molded body. When irregularities are present on the surface of a PFA molded body, contaminants tend to accumulate in these irregularities. For example, Non-Patent Document 1 describes adding PTFE as a nucleating agent to refine spherulites, but since the PTFE added as a nucleating agent itself becomes a source of contamination, there is a need to improve the surface smoothness of PFA molded articles without adding a nucleating agent.

[0007] In view of the above circumstances, one embodiment of the present disclosure aims to solve the problem of providing a composition that can produce a molded article with excellent surface smoothness, and a method for producing the composition. Other embodiments of this disclosure aim to solve the problem of providing a molded article and a coated electric wire using the above composition. [Means for solving the problem]

[0008] The means for solving the above problems include the following embodiments. <1> A composition comprising a copolymer containing a tetrafluoroethylene-based structural unit and a perfluoro(alkyl vinyl ether)-based structural unit, The content of tetrafluoroethylene-based constituent units is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer. The content of perfluoro(alkyl vinyl ether) based constituent units is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer. The melt flow rate measured under conditions of 372°C is 1.0 to 40.0 g / 10 min. In the melting curve observed by heating the composition from 200 °C to 350 °C at a rate of 10 °C / min using a differential scanning calorimeter, with respect to the peak area indicating the heat of fusion determined by connecting the points where the melting curve deviates from and returns to the baseline before and after the melting peak with a straight line, the ratio A of the peak area determined from the curve between 315 °C and 330 °C in the melting curve to the peak area determined from the straight line is 1 to 20%, and the slope of the straight line connecting the heat flow at 315 °C and the heat flow at 320 °C is a positive value. Composition. <2> The composition according to claim 1, wherein the structural unit based on perfluoro(alkyl vinyl ether) contains a structural unit based on perfluoro(propyl vinyl ether). <3> The composition according to <1> or <2>, having a melt flow rate measured under the condition of a temperature of 372 °C of 1.0 to 19.0 g / 10 min. <4> The total number of functional groups selected from the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH per 10 main chain carbon atoms of the copolymer is 50 or less. The composition according to any one of <1> to <3>. 6 The composition according to any one of <1> to <3>, wherein the ratio A is 5 to 20%. <5> The composition according to any one of <1> to <4>, wherein the ratio A is 5 to 20%. <6> A molded article of the composition according to any one of <1> to <5>. <7> The molded article according to <6>, which is a tube, a joint, a sheet, a nut, a tank, an electric wire coating material, or a compression member. <8> A coated electric wire comprising a conductor and a coating layer disposed on the surface of the conductor and containing the composition according to any one of <1> to <5>. <9> Using tetrafluoroethylene and perfluoro(alkyl vinyl ether) as raw materials, polymerization is carried out by a solution polymerization method, including producing a composition containing a copolymer comprising a structural unit based on tetrafluoroethylene and a structural unit based on perfluoro(alkyl vinyl ether). The content of the structural unit based on tetrafluoroethylene is 93.0 to 98.0% by mass based on all monomer units of the copolymer. The content of the structural unit based on perfluoro(alkyl vinyl ether) is 2.0 to 7.0% by mass based on all monomer units of the copolymer. The melt flow rate measured under the condition of a temperature of 372 °C is 1.0 to 40.0 g / 10 min. When 5 to 12 mol% of perfluoro(alkyl vinyl ether) is consumed with respect to the amount of perfluoro(alkyl vinyl ether) used at the start of polymerization during the polymerization, tetrafluoroethylene is added at 15 to 65 mol% with respect to the total amount of perfluoro(alkyl vinyl ether) and tetrafluoroethylene used at the start of polymerization. A method for producing a composition. <10> The method for producing the composition according to <9>, wherein the polymerization is carried out in a liquid medium containing a hydrofluoroether. <11> The method for producing the composition according to <10>, wherein the hydrofluoroether is 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

Advantages of the Invention

[0009] The problem to be solved by one embodiment of the present disclosure is to provide a composition capable of obtaining a molded body excellent in surface smoothness and a method for producing the composition. The problem to be solved by another embodiment of the present disclosure is to provide a molded body using the above composition and a coated electric wire.

Brief Description of the Drawings

[0010] [Figure 1] Figure 1 is a schematic diagram for explaining ratio A. [Modes for carrying out the invention]

[0011] The embodiments for carrying out the embodiments of this disclosure will be described in detail below. However, the embodiments of this disclosure are not limited to the embodiments described below. In the embodiments described below, the components (including elemental steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the embodiments of this disclosure.

[0012] In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, provided that the purpose of such process is achieved. In this disclosure, the numerical range indicated using "~" includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition, unless otherwise specified. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In this disclosure, "polymer" refers to a compound formed by the polymerization of monomers. That is, a "polymer" has multiple structural units. In this disclosure, "polymer" is a compound obtained by copolymerizing two or more monomers. A copolymer containing units based on monomer X and units based on monomer Y is a compound obtained by copolymerizing at least monomer X and monomer Y, and other monomers may or may not be further copolymerized. In this disclosure, "unit" refers to a collective term for atomic groups derived from one monomer molecule that are directly formed by the polymerization of monomers, and atomic groups obtained by chemically transforming a part of the above atomic group. In the following, as appropriate, units derived from individual monomers will be referred to by adding "unit" to the monomer name.

[0013] <Composition> The composition of the present disclosure is a copolymer comprising a tetrafluoroethylene-based structural unit and a perfluoro(alkyl vinyl ether)-based structural unit. The copolymer contained in the present disclosure has a tetrafluoroethylene-based structural unit content of 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, and a perfluoro(alkyl vinyl ether)-based structural unit content of 2.0 to 7.0% by mass relative to the total monomer units of the copolymer. The composition of the present disclosure has a melt flow rate of 1.0 to 40.0 g / 10 min as measured under conditions of a temperature of 372°C. In the composition of this disclosure, the melting curve observed when the composition is heated from 200°C to 350°C at a rate of 10°C / min using a differential scanning calorimeter, the ratio A of the peak area representing the heat of fusion, which is determined by drawing a straight line connecting the point where the melting curve deviates from the baseline and the point where it returns to the baseline before and after the melting peak, to the peak area determined by the curve from 315°C to 330°C and the straight line is 1% to 20%, and the slope of the straight line connecting the heat flow at 315°C and the heat flow at 320°C is a positive value.

[0014] In particular, the composition of this disclosure yields a molded article with excellent surface smoothness when the above proportion A is 1% to 20% and the slope of the straight line connecting the heat flow at 315°C and the heat flow at 320°C is a positive value. The reason for this is unclear, but it can be speculated as follows:

[0015] The peak area determined from the curve between 315°C and 330°C in the melting curve and the straight line mentioned above is due to the copolymer containing units based on tetrafluoroethylene and units based on perfluoro(alkyl vinyl ether). Of these, the above proportion A corresponds to the proportion of components in the copolymer that have a small content of units based on perfluoro(alkyl vinyl ether) and higher crystallinity. When the copolymer melted during melt molding is cooled, recrystallization usually proceeds from the highly crystalline components, and these become spherulites. If the above proportion A is 1-20%, the spherulites formed in the initial stages of cooling act as nucleating agents, and the main components that did not recrystallize in the initial stages of cooling recrystallize from the vicinity of the spherulites while the degree of supercooling is small. As a result, the diameter of the spherulites in the copolymer at the end of cooling is small. Due to this effect, a molded article with excellent surface smoothness can be obtained without adding PTFE as a nucleating agent. When PTFE is added as a nucleating agent, the main component PFA and the additive PTFE do not become completely miscible even after melt molding because their phase transition behavior and molecular structures are significantly different. In this case, spherulites derived from PFA are formed from spherulites derived from miscible PTFE, which can result in a variation in the degree of supercooling required for crystallization during cooling. Therefore, even with the addition of PTFE, a variation in spherulite diameter and a variation in the smoothness of the distribution surface may occur. When PTFE is added, the melting curve in differential scanning calorimetry has two peaks in the heat of fusion. In this case, the slope of the heat flow at 315°C and the heat flow at 320°C is negative because there is a peak in the heat of fusion originating from PTFE in the temperature range above 320°C. In other words, the composition of this disclosure, in which the slope of the heat flow at 315°C and the heat flow at 320°C are positive, does not have a peak in the heat of fusion originating from PTFE, and each component in the composition is uniformly miscible, so there is no distribution in the diameter of the spherulites produced, and a molded article with excellent surface smoothness can be obtained without adding PTFE.

[0016] Hereinafter, copolymers containing units based on tetrafluoroethylene and units based on perfluoro(alkyl vinyl ether) will also be referred to as "this copolymer," units based on tetrafluoroethylene will also be referred to as "TFE units," and units based on perfluoro(alkyl vinyl ether) will also be referred to as "PAVE units."

[0017] Since the compositions described in Patent Documents 1 and 2 contain PTFE, in the melting curve observed when the composition is heated from 200°C to 350°C at a rate of 10°C / min using a differential scanning calorimeter, the slope of the straight line connecting the heat flow at 315°C and the heat flow at 320°C is not a positive value.

[0018] [DSC measurement] In the composition disclosed herein, the composition is heated from 200°C to 350°C at a rate of 10°C / min using a differential scanning calorimeter (DSC), and in the melting curve observed, the ratio A of the peak area representing the heat of fusion, which is determined by drawing a straight line connecting the point where the melting curve deviates from the baseline and the point where it returns to the baseline before and after the melting peak, is 1% to 20%.

[0019] In a melting curve observed by heating a composition from 200°C to 350°C at a rate of 10°C / min using DSC, the peak area, determined by drawing straight lines connecting the points where the melting curve deviates from the baseline and where it returns to it before and after the melting peak, represents the heat of fusion.

[0020] From the viewpoint of suppressing the amount of heat required during melt molding, the heat of fusion of the composition disclosed herein is preferably 10 to 50 J / g, more preferably 15 to 40 J / g, and even more preferably 17 to 30 J / g.

[0021] The composition disclosed herein allows for the production of a molded article with excellent surface smoothness, provided that the ratio A of the peak area determined from the curve between 315°C and 330°C in the melting curve and the straight line is 1% to 20% of the peak area indicating the heat of fusion.

[0022] Figure 1 is a schematic diagram illustrating proportion A. In Figure 1, the melting curve is represented by curve X. The straight line Y is the line connecting the point where the melting curve deviates from the baseline and the point where it returns to the baseline around the melting peak. The region enclosed by curve X and line Y represents the peak area indicating the heat of fusion. The shaded area in Figure 1 represents the peak area determined by the curve and line Y in the melting curve from 315°C to 330°C. In Figure 1, ratio A is the ratio of the peak area shown in the shaded area to the peak area showing the heat of fusion.

[0023] When proportion A is 1% or more, the surface smoothness of the molded body is excellent due to the nucleating effect of the copolymer, which has a high TFE unit content in the copolymer contained in the composition. When proportion A is 20% or less, the components contained in the composition are easily compatible, resulting in excellent surface smoothness of the molded article.

[0024] From the viewpoint of further improving the smoothness of the molded surface, the ratio A is preferably 1-20%, and more preferably 5-20%.

[0025] Methods for obtaining a composition in which proportion A is 1% to 20% include, for example, a dry blending method of copolymers having different TFE unit and PAVE unit contents in powder or pellet form, a wet blending method of dispersion liquids, and the method for producing the composition of the present disclosure described later, with the method for producing the composition of the present disclosure described later being preferred.

[0026] Furthermore, in the melting curve observed when the composition is heated from 200°C to 350°C at a rate of 10°C / min using DSC, the slope of the line connecting the heat flow at 315°C and the heat flow at 320°C (hereinafter also referred to as "slope T") is a positive value.

[0027] A positive slope T means that the heat flow value at 315°C is smaller than the heat flow value at 320°C.

[0028] The slope T is calculated based on the following formula. Slope T [mW / (mg·℃)] = ("Heat flow value at 320℃" - "Heat flow value at 315℃") / 5

[0029] The heat flow value at 315°C is preferably -0.60 to -0.10 mW / mg, and more preferably -0.55 to -0.15 mW / mg. The heat flow value at 320°C is preferably -0.55 to -0.10 mW / mg, and more preferably -0.55 to -0.15 mW / mg. The slope T is preferably 0.0010 to 0.0200 mW / (mg·℃), and more preferably 0.0020 to 0.0150 mW / (mg·℃).

[0030] Since the melting point of PTFE is 327°C, if the composition contains PTFE, the melting curve will be bimodal, and the slope T will be a negative value.

[0031] One method for obtaining a composition in which the above-mentioned slope T is a positive value is to adjust the mixing ratio of copolymers in which the content of TFE units and PAVE units differs from each other.

[0032] [Melt flow rate] The melt flow rate (MFR) of the composition is 1.0 to 40.0 g / 10 min. When the MFR is 1.0g / 10min or higher, the melt moldability is excellent. A molded product exhibits superior mechanical strength when the MFR (Metal Flow Rate) is 40.0 g / 10 min or less.

[0033] From this viewpoint, the MFR of the composition is preferably 1.0 to 40.0 g / 10 min, more preferably 1.0 to 19.0 g / 10 min, and even more preferably 2.0 to 18.0 g / 10 min. A specific example of a method to bring the MFR of this copolymer within the above range is to adjust the molecular weight of the copolymer. The larger the molecular weight of this copolymer, the smaller the MFR. The MFR of a copolymer refers to the mass (g) of copolymer flowing out of a 2.095 mm diameter, 8 mm length orifice in 10 minutes, measured under ASTM D1238 conditions of 372°C and a 5 kg load. The copolymer and other components contained in the composition are described in detail below.

[0034] [This copolymer] This copolymer contains TFE units and PAVE units. The TFE units represent 93.0 to 98.0% by mass of the total monomer units of this copolymer. The PAVE units are 2.0 to 7.0% by mass relative to the total monomer units of this copolymer.

[0035] From the viewpoint of increasing the strength of the molded article, the TFE unit content is preferably 93.0% by mass or more, more preferably 93.5% by mass or more, and even more preferably 94.0% by mass or more, relative to the total monomer units of the copolymer. From the viewpoint of increasing the flexibility of the molded article, the TFE unit content is preferably 98.0% by mass or less, more preferably 97.5% by mass or less, and even more preferably 97.0% by mass or less, relative to the total monomer units of the copolymer.

[0036] From the viewpoint of improving the flexibility of the molded article, the PAVE unit content is preferably 2.0% by mass or more, more preferably 2.5% by mass or more, and even more preferably 3.0% by mass or more, relative to the total monomer units contained in the copolymer. From the viewpoint of improving the crystallinity of the copolymer and improving the strength of the molded article, the PAVE unit content is preferably 7.0% by mass or less, more preferably 6.5% by mass or less, and even more preferably 6.0% by mass or less, relative to the total monomer units contained in the copolymer.

[0037] As PAVE, the monomer represented by formula (1) is preferred. CF2 = CF - O - Rf 1 (1) In formula (1), Rf 1 Rf represents a perfluoroalkyl group with 1 to 10 carbon atoms. 1The number of carbon atoms in the perfluoroalkyl group represented by is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3 from the viewpoint of more excellent polymerization reactivity. The perfluoroalkyl group may be linear or branched.

[0038] Specific examples of PAVE include perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE). From the viewpoint of excellent balance between raw material cost and ease of handling during polymerization, PMVE or PPVE is preferable, and PPVE is more preferable. PAVE may be used alone or in combination of two or more.

[0039] In this copolymer, from the viewpoints of favorably exhibiting the characteristics of the TFE unit and the PAVE unit, and the molded body being difficult to be easily deformed by compression or tension, the total content of the TFE unit and the PAVE unit is preferably 95.0% by mass or more, more preferably 98.0% by mass or more, still more preferably 99.0% by mass or more, and may be 100.0% by mass with respect to all the monomer units contained in this copolymer.

[0040] This copolymer may or may not contain units based on other monomers copolymerizable with TFE and PAVE in addition to the TFE unit and the PAVE unit. Examples of other monomers include, for example, ethylene, vinylidene fluoride (VdF), hexafluoropropylene (HFP), CX 1 X 2 =CX 3 (CF2) n X 4 (wherein X 1 X 2 and X 3 each independently represents a hydrogen atom or a fluorine atom, X 4 represents a hydrogen atom, a fluorine atom, or a chlorine atom, and n represents an integer of 1 to 10.) and CF2=CF-OCH2-Rf 2 [[ID=3?]](wherein Rf 2) represents a perfluoroalkyl group having 1 to 5 carbon atoms. Examples include monomers represented by ). If the copolymer contains units based on other monomers, the content of units based on other monomers is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less, relative to the total monomer units contained in the copolymer.

[0041] From the viewpoint of exhibiting the properties of TFE units and PAVE units well, and from the viewpoint of the molded article not being easily deformed by compression or tension, it is preferable that this copolymer does not contain units based on other monomers and contains only TFE units and PAVE units. In this case, the total content of TFE units and PAVE units is 100.0% by mass relative to the total monomer units contained in this copolymer.

[0042] The respective contents of TFE units, PAVE units, and other monomer-based units in this copolymer are: 19 It can be measured by known methods such as F-NMR (nuclear magnetic resonance analysis).

[0043] In this copolymer, the total number of specific functional groups selected from the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH (hereinafter also referred to as "specific functional groups") is such that the main chain of this copolymer has 10 carbon atoms. 6 The number of specific functional groups per unit is preferably 200 or less, more preferably 100 or less, even more preferably 50 or less, particularly preferably 10 or less, and extremely preferably 6 or less. By keeping the number of specific functional groups below the above upper limit, decomposition from terminal functional groups is suppressed, thus improving the heat resistance of the molded article. A small number of specific functional groups is preferable, but the number of carbon atoms in the main chain is 10 6 Each item can contain one or more, two or more, or three or more.

[0044] Specific functional groups are functional groups present at the ends of the main chain or side chains of the copolymer, and functional groups present in the main chain or side chains. Specific functional groups are introduced into the copolymer, for example, by the chain transfer agent or polymerization initiator used in its production. More specifically, for example, if an alcohol is used as the chain transfer agent, or if a peroxide having the structure -CH2OH is used as the polymerization initiator, -CH2OH is introduced to the ends of the main chain of the copolymer. Furthermore, specific functional groups can also be introduced to the ends of the side chains of the copolymer by polymerizing monomers containing functional groups. Furthermore, if the number of functional groups in this copolymer having specific functional groups exceeds a predetermined range, the number of functional groups can be reduced by fluorinating the copolymer and converting the specific functional groups to -CF3 terminal groups. The number of functional groups in this copolymer can be adjusted by changing the conditions of the fluorination treatment (treatment time, etc.).

[0045] The types and number of functional groups in this copolymer can be determined by infrared spectroscopy. Specifically, the number of functional groups is measured by the following method. First, the copolymer is molded by hot pressing at 330°C to produce a film with a thickness of 0.25 to 0.30 mm. This film is analyzed by Fourier transform infrared spectroscopy (FT-IR) to obtain the infrared absorption spectrum of the copolymer. Separately, an infrared absorption spectrum (base spectrum) is obtained from a completely fluorinated copolymer that does not contain specific functional groups, and the difference spectrum between the infrared absorption spectrum and the base spectrum of the copolymer is obtained. From the absorption peak of the specific functional group appearing in this difference spectrum, the number of carbon atoms in the main chain of the copolymer (10) is determined according to the following formula (A). 6 Calculate the number of functional units N per individual.

[0046] N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm)

[0047] Table 1 shows the absorption frequency, molar extinction coefficient, and correction factor for specific functional groups. The molar extinction coefficient of specific functional groups is determined from FT-IR (Fourier transform infrared spectroscopy) measurement data of low-molecular-weight model compounds.

[0048] [Table 1]

[0049] In this copolymer, the absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are obtained by subtracting several tens of Kaiser (cm) from the respective absorption frequencies of -CF2H, -COF, -COOH (free and bonded), -COOCH3, and -CONH2 shown in the table. -1 ) becomes lower. For example, the number of -COFs is such that the absorption frequency at 1883 cm⁻¹ is due to -CF2COF. -1 The number of functional groups determined from the absorption peak and the absorption frequency of 1840 cm² due to -CH2COF -1 This is the sum of the number of functional groups determined from the absorption peaks.

[0050] From the viewpoint of excellent mechanical strength of the molded article, the melting point of this copolymer is preferably 298.0°C or higher, more preferably 299.0°C or higher, and even more preferably 300.0°C or higher. From the viewpoint of excellent moldability of this copolymer and excellent low-speed tear strength of the molded article, the melting point of this copolymer is preferably 310.5°C or lower, more preferably 310.0°C or lower, and even more preferably 309.5°C or lower. One method for setting the melting point of this copolymer within the above range is to lower the polymerization temperature during the production of this copolymer. The melting point of this copolymer is the temperature corresponding to the endothermic peak when the copolymer is heated at a rate of 10°C / min in an air atmosphere using a scanning differential thermal analyzer.

[0051] The term "polymer" here is intended to distinguish it from so-called elastomers. Elastomers are copolymers that do not have a melting point.

[0052] [Other ingredients] The compositions of this disclosure may or may not contain components other than the copolymer. For example, the compositions of this disclosure may contain resins other than the copolymer, heat stabilizers, antioxidants, colorants, ultraviolet absorbers, fillers, crosslinking agents, crosslinking aids, organic peroxides, etc. If the composition of this disclosure contains components other than the copolymer, the total content of such components is preferably 70 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 10 parts by mass or less, particularly preferably 1 part by mass or less, and very preferably 0.1 parts by mass or less, per 100 parts by mass of the copolymer. The total content of components other than the copolymer may be 0.0000001 parts by mass or more, 0.0000005 parts by mass or less, or 0.000001 parts by mass or more, per 100 parts by mass of the copolymer. From this viewpoint, the total content of components other than the copolymer may be 0.0000001 to 70 parts by mass, per 100 parts by mass of the copolymer.

[0053] In order to make the above slope T a positive value, it is preferable that the compositions of this disclosure do not contain PTFE. If PTFE is included, it is preferably 0.009 parts by mass or less, and more preferably 0.008 parts by mass or less, per 100 parts by mass of the copolymer.

[0054] The form of the compositions disclosed herein is not particularly limited, but the compositions disclosed herein are preferably solid compositions. "Solid composition" means a composition that is solid at 25°C.

[0055] [Method for manufacturing the composition] The method for producing the composition of the present disclosure includes a step (hereinafter also referred to as the "polymerization step") in which TFE and PAVE are used as raw materials, and polymerization is carried out by a solution polymerization method to produce a composition containing a copolymer containing TFE units and PAVE units, wherein the TFE unit content is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, the PAVE unit content is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer, the melt flow rate measured under conditions of a temperature of 372°C is 1.0 to 40.0 g / 10 min, and when PAVE has been consumed at a rate of 5 to 12 mol% relative to the amount of PAVE used at the start of polymerization, TFE is added at a rate of 15 to 65 mol% relative to the total amount of PAVE and TFE used at the start of polymerization.

[0056] In general manufacturing methods, all raw materials are used at the start of polymerization, but in the method for manufacturing the composition of the present disclosure, the composition of the present disclosure can be manufactured by adding TFE later during polymerization. Specifically, according to the method for manufacturing the composition of the present disclosure, a composition can be manufactured that contains a copolymer containing TFE units and PAVE units, wherein the TFE unit content is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, the PAVE unit content is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer, the MFR is 1.0 to 40.0 g / 10 min, the ratio A is 1% to 20%, and the slope T is a positive value.

[0057] During polymerization, the amount of PAVE consumed relative to the amount of PAVE used at the start of polymerization is determined by the following method. When the continuous addition amount of TFE after the start of polymerization reaches 160 g, the polymerization is terminated, the obtained slurry is filtered to separate the polymerization medium, and then dried at 100°C for 15 hours, and the resulting white powder is... 19 The molar ratio of PAVE is calculated using a F-nuclear magnetic resonance spectrometer (AVANCE-III-HD400, manufactured by Bruker Biospin). The relationship between the amount of PAVE used and the molar ratio allows for the determination of PAVE consumption.

[0058] Adding TFE when PAVE consumption is 5 mol% or higher can relatively increase the proportion of TFE units in the copolymer produced after TFE addition. When TFE is added when PAVE consumption is 12 mol% or less, the proportion of copolymers with a relatively large proportion of TFE units in the copolymer produced after TFE addition does not become too large, making it easier to control the composition of the copolymer produced through polymerization. From this perspective, the amount of PAVE consumed at the time of TFE addition is more preferably 5 to 12 mol%, and even more preferably 6 to 11 mol%.

[0059] During polymerization, by adding 15 to 65 mol% of TFE at a predetermined time point relative to the total amount of PAVE and TFE used at the start of polymerization, a copolymer can be obtained in the polymerization process from that point onward where the proportion of TFE units is higher than the proportion of TFE units relative to PAVE units and TFE units at the start of polymerization. A copolymer with a high proportion of TFE units is not PTFE, but it can be said to have a composition close to that of PTFE. Since the composition obtained by the manufacturing method of this disclosure contains PFA with a composition close to that of PTFE, a molded article with excellent surface smoothness can be obtained.

[0060] As described above, the copolymers contained in the compositions obtained by the method for producing the compositions of this disclosure contain TFE units and PAVE units, and include copolymers in which the ratio of TFE units to PAVE units is relatively low and copolymers in which the ratio of TFE units is relatively high. Thus, when considering the copolymers on a molecule-by-molecule basis, the proportion of TFE units differs from molecule to molecule, but when considered as an aggregate, the TFE unit content is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, and the PAVE unit content is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer.

[0061] Even when polymerization is carried out using all the raw materials at the start of polymerization, the ratio of each constituent unit in the resulting copolymer will have some degree of distribution. In contrast, the method for producing the composition of this disclosure involves adding TFE during polymerization, resulting in a larger distribution. However, measuring this distribution is difficult.

[0062] The amount of TFE added when 5-12 mol% of PAVE has been consumed is 15-65 mol% of the total amount of PAVE and TFE used at the start of polymerization, preferably 16-60 mol%, and more preferably 17-60 mol%, from the viewpoint of easily increasing the TFE unit content in the copolymer obtained after TFE addition.

[0063] Furthermore, after polymerization has started, TFE may be continuously added before 5 to 12 mol% of PAVE relative to the amount of PAVE used at the start of polymerization has been consumed. By continuously adding TFE after polymerization has started, the pressure during polymerization can be maintained at the same level as the pressure at the start of polymerization.

[0064] Furthermore, TFE may be added in an amount of 15-65 mol% relative to the total amount of PAVE and TFE used at the start of polymerization, and then TFE may be added continuously. By adding TFE in addition and then continuously adding TFE, the pressure during polymerization can be maintained at the same level as the pressure at the start of polymerization.

[0065] In the polymerization process, in addition to the above monomers (TFE, PAVE, and other monomers as needed), polymerization initiators, polymerization media, chain transfer agents, emulsifiers, pH adjusters, etc., can be used.

[0066] The polymerization initiator is preferably a radical polymerization initiator with a half-life of 10 hours and a temperature range of 0 to 100°C, and more preferably a radical polymerization initiator with a temperature range of 20 to 90°C. Specific examples of polymerization initiators include the various polymerization initiators exemplified in International Publication No. 2013 / 015202. The polymerization initiator may be used alone or in combination of two or more types. The amount of polymerization initiator used is preferably 0.01 to 0.9 parts by mass, and more preferably 0.05 to 0.5 parts by mass, per 100 parts by mass of monomer used.

[0067] Polymerization media include water, organic solvents, and mixed solvents of water and organic solvents. Examples of organic solvents include fluorine-based solvents such as perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers. Specific examples of organic solvents include the polymerization media exemplified in International Publication No. 2013 / 015202. Polymerization media containing water are preferred. Ultrapure water is more preferred as the water.

[0068] In particular, from the viewpoint of balancing viscosity and thermal conductivity, the polymerization medium preferably contains a hydrofluoroether. That is, polymerization is preferably carried out in a liquid medium containing a hydrofluoroether.

[0069] Examples of hydrofluoroethers include methoxynononafluorobutane (HFE-7100), 1,1-difluoroethyl-2,2,2-trifluoroethyl ether (HFE-365mf-c), 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (HFE-347pc-f), 1,1-difluoroethyl-2,2,3,3,3-pentafluoropropyl ether (HFE-467sc-f), ethoxynononafluorobutane (HFE-569s1), 1,1,2,3,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether (HFE-449mec-f), and 1,1,2,2-tetrafluoroethyl-2,2,3,3,3-pentafluoropropyl ether (HFE-449 Examples include pc-f), 1,1-difluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE-476pcf-c), 1,1,2,3,3,3-hexafluoropropyl-2,2,3,3,3-pentafluoropropyl ether (HFE-54-11mec-f), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (HFE-458pc-fc), 1,1,2,3,3,3-hexafluoropropyl-2,2,3,3-tetrafluoropropyl ether (HFE-55-10mec-fc), and 3-methoxy-4-trifluoromethyl-1,1,1,2,2,3,4,5,5,5-decafluoropentane (C2F5CF(OCH3)CF(CF3)CF3).

[0070] In particular, from the viewpoint of polymerization reactivity, the hydrofluoroether is preferably 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

[0071] From the viewpoint of easily obtaining copolymers with low metal element content, the water is preferably of 2.0 ppm by mass or less, more preferably 1.0 ppm by mass or less, even more preferably 0.5 ppm by mass or less, and particularly preferably 0.1 ppm by mass or less. The metal element content is preferably 0 ppb by mass or more. The method for achieving the above-mentioned metal element content is not particularly limited, and examples include methods such as filtering water with various filters to reduce the metal element content. The metallic element content in water can be measured using an absolute calibration curve method with ICP-MS. The electrical conductivity of water is preferably 1.00 μS / cm or less, and more preferably 0.08 μS / cm or less. The lower limit is preferably 0 μS / cm or more. The magnitude of the electrical conductivity of water is related to the amount of metallic elements in the water; the more metallic elements there are, the higher the electrical conductivity of the water. The electrical conductivity of water can be measured by known measurement methods.

[0072] The polymerization medium may be used alone or in combination of two or more types. A mixed solvent of water and a fluorinated solvent is preferred as the polymerization medium, and a mixed solvent of water and perfluorocarbon is more preferred. From the viewpoint of suspendability and economic efficiency, the amount of fluorinated solvent used is preferably 10% by mass or more and less than 100% by mass of the total mass of the mixed solvent. The amount of polymerization medium used is preferably 3 times or more by mass ratio of the amount of monomer used, and more preferably 5 times or more. Furthermore, the amount of polymerization medium used is preferably 20 times or less by mass ratio of the amount of monomer used, and more preferably 17 times or less. From this viewpoint, the amount of polymerization medium used is preferably 3 to 20 times, and more preferably 5 to 17 times, by mass ratio of the amount of monomer used.

[0073] From the viewpoint of having a large chain transfer constant and requiring a small amount of addition, alcohols such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, and 2,2,3,3,3-pentafluoropropanol are preferred as chain transfer agents; hydrocarbons such as n-pentane, n-hexane, and cyclohexane are preferred; hydrofluorocarbons such as CF2H2 are preferred; ketones such as acetone are preferred; mercaptans such as methyl mercaptan are preferred; esters such as methyl acetate and ethyl acetate are preferred; and ethers such as diethyl ether and methyl ethyl ether are preferred. In particular, from the viewpoint of a higher chain transfer constant and greater stability of the end groups of the copolymer, at least one selected from the group consisting of alcohols, hydrocarbons, and hydrofluorocarbons is preferred, at least one selected from the group consisting of alcohols and hydrocarbons is more preferred, and alcohols are even more preferred. Among the alcohols, methanol or ethanol is preferred, and methanol is more preferred from the viewpoint of reactivity and availability. The chain transfer agent may be used alone or in combination of two or more. The amount of chain transfer agent used is preferably 0.001 times or more by mass ratio of the amount of monomer used, and more preferably 0.005 times or more. Furthermore, the amount of chain transfer agent used is preferably 5 times or less by mass ratio of the amount of monomer used, and more preferably 4 times or less. From this viewpoint, the amount of chain transfer agent used is preferably 0.001 to 5 times, and more preferably 0.005 to 4 times, by mass ratio of the amount of monomer used.

[0074] As for the compounds used in polymerization (monomer components, polymerization initiators, chain transfer agents, emulsifiers, pH adjusters, etc., excluding aqueous media), it is preferable not to use compounds containing metal elements, from the viewpoint of easily obtaining compositions with low metal element content.

[0075] The polymerization temperature is preferably 15 to 60°C, more preferably 20 to 58°C, and even more preferably 25 to 55°C. A polymerization temperature of 15°C or higher may result in excellent polymerizability. A polymerization temperature of 60°C or lower may improve the melting point of the copolymer. The polymerization pressure is preferably 0.5 to 3.0 MPa, and more preferably 0.9 to 2.5 MPa. The polymerization time is preferably 1 to 12 hours.

[0076] If an aqueous dispersion containing the copolymer is obtained by carrying out the polymerization process, the copolymer can be recovered by coagulating, washing, and drying the copolymer contained in the aqueous dispersion. Alternatively, if the copolymer is obtained as a slurry by polymerization, the copolymer can be recovered by removing the slurry from the reaction vessel, washing, and drying it. The copolymer can also be recovered in powder form by drying.

[0077] [Fluorination process] The method for producing the composition of the present disclosure may further include a step of fluorinating the copolymer obtained in the polymerization step (this step is also referred to as the "fluorination step"). By fluorination, specific functional groups consisting of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H that the copolymer may have can be converted to -CF3. This reduces the number of specific functional groups, making it easier to adjust the number of functional groups in the copolymer within a predetermined range.

[0078] Fluorination treatment is carried out by contacting an unfluorinated copolymer with a fluorine-containing compound. Examples of fluorine-containing compounds include fluorine radical sources that generate fluorine radicals under fluorination treatment conditions. Examples of the above fluorine radical sources include F2 gas, N2F2, and halogenated fluorides (e.g., IF5 and ClF3).

[0079] The concentration of the fluorine radical source, such as F2 gas, may be 100% by volume. From a safety standpoint, it is preferable to use a mixed gas obtained by diluting F2 gas with an inert gas so that the concentration is 5 to 50% by volume (preferably 15 to 30% by volume). Examples of inert gases include nitrogen gas, helium gas, and argon gas, and from an economic standpoint, nitrogen gas is preferred.

[0080] The temperature during the fluorination treatment is preferably below the melting point of the copolymer, more preferably 20 to 240°C, and even more preferably 100 to 235°C. The fluorination treatment may also be carried out by contacting the molten copolymer with a fluorine-containing compound.

[0081] Specific methods for fluorination treatment include, for example, placing a shelf on which the copolymer is placed inside an oven, filling the oven with F2 gas or a mixed gas, and heating it for a certain period of time. Another method involves heating a flow-through column filled with copolymer pellets while flowing F2 gas or a mixed gas through the column for a certain period of time. The processing time for the fluorination treatment can be appropriately adjusted depending on the number of functional groups in the copolymer before fluorination, the desired number of functional groups, and the fluorination treatment method. For example, it is 0.5 to 30 hours, with 1 to 24 hours being preferred.

[0082] [Molded body] The molded articles of the present disclosure are molded articles of the compositions of the present disclosure. The molded articles of this disclosure are obtained by molding the compositions of this disclosure.

[0083] Specific examples of the molded articles of this disclosure include injection-molded articles obtained by injection molding of a composition, extruded articles obtained by extrusion molding, blow-molded articles obtained by blow molding, transfer-molded articles obtained by transfer molding, press-molded articles obtained by press molding, rotationally molded articles obtained by rotational molding, and coatings obtained by electrostatic coating. Press-molded articles obtained by press molding are preferred for the molded articles of the present invention. Injection-molded articles are also preferred because they can be obtained with a beautiful appearance without corroding the mold used for molding.

[0084] Furthermore, examples of the forms of the molded articles of this disclosure include pellets and powders. The molded articles of this disclosure can be molded by conventionally known methods. Examples of molding methods for the molded articles include extruding a composition while melting it using a single-screw extruder, a twin-screw extruder, or a tandem extruder, cutting it to a predetermined length, and forming it into pellets. The extrusion temperature in melt extrusion is appropriately changed depending on the melt viscosity of the composition and the manufacturing method, but it is preferably 20 to 140°C or more higher than the melting point of the composition. Conventional known methods such as strand cutting, hot cutting, underwater cutting, and sheet cutting can be used for cutting the molded body. Volatile components in the pellets may be removed by heating the obtained pellets (degassing treatment). The obtained pellets may also be treated by contacting them with hot water at 30 to 200°C, steam at 100 to 200°C, or hot air at 40 to 200°C.

[0085] Specific examples of molded articles of this disclosure include nuts, bolts, fittings, films, bottles, gaskets, wire insulation materials, tubes, hoses, pipes, valves, seats, seals, packings, tanks, rollers, containers, cocks, connectors, filter housings, filter cages, flow meters, pumps, wafer carriers, and wafer boxes.

[0086] The molded articles of this disclosure can be used for the following purposes: Fluid transfer components for food manufacturing equipment, such as food packaging films, lining materials for fluid transfer lines used in food manufacturing processes, packings, seals, and sheets; chemical stoppers, packaging films, lining materials for fluid transfer lines used in pharmaceutical manufacturing processes, packings, seals, and sheets; internal lining components for chemical tanks and piping in chemical plants or semiconductor factories; O-rings, tubes, packings, valve cores, hoses, and seals used in automobile fuel systems and peripheral equipment, as well as hoses and seals used in automobile automatic transmission systems; carburetor flange gaskets, shaft seals, valve stem seals, seals, and hoses used in automobile engines and peripheral equipment, as well as other automobile components such as brake hoses, air conditioning hoses, radiator hoses, and wire insulation materials; semiconductor components such as O-rings, tubes, packings, valve cores, hoses, seals, rolls, gaskets, diaphragms, and fittings for semiconductor manufacturing equipment. Examples include: chemical liquid transfer components for equipment; paint and ink components such as paint rolls, hoses, tubes, and ink containers for painting equipment; food and beverage transfer components such as tubes or hoses for food and beverages, hoses, belts, gaskets, fittings, food packaging materials, and glass cooking equipment; waste liquid transport components such as tubes and hoses for waste liquid transport; high-temperature liquid transport components such as tubes and hoses for high-temperature liquid transport; steam piping components such as tubes and hoses for steam piping; corrosion-resistant tapes for piping such as tapes wrapped around piping on ship decks, etc.; various coating materials such as wire coating materials, optical fiber coating materials, transparent surface coating materials and backing materials provided on the light incident side surface of photovoltaic elements of solar cells; sliding components such as diaphragms and various gaskets for diaphragm pumps; agricultural films, carrier films for fuel cells, and weather-resistant covers for various roofing materials and side walls, etc.; interior materials used in the building sector, and coating materials for glass such as non-combustible fire-resistant safety glass; lining materials such as laminated steel sheets used in the home appliance sector, etc.

[0087] In particular, the molded articles of this disclosure can be suitably used as sheets, tubes, fittings, nuts, sheets, tanks, wire coverings, or members to be compressed.

[0088] The compressible member is a member used in a compressed and deformed state, and its size and shape are appropriately set according to the application. The shape of the compressible member may be, for example, annular. The compressible member may also have a circular, oval, or rounded-corner rectangle shape in plan view, and may have a through hole in its center.

[0089] The compressible member can be used as a piping component for transferring fluids. Furthermore, the compressible member can be used as a component for constructing a non-aqueous electrolyte battery, and is particularly suitable as a component used in contact with the non-aqueous electrolyte in a non-aqueous electrolyte battery.

[0090] The compressible member can also be suitably used as a sealing member, such as a sealing gasket and sealing packing, and as an insulating member, such as an insulating gasket and insulating packing. A sealing member is a member used to prevent leakage of liquid or gas, or intrusion of liquid or gas from the outside. An insulating member is a member used to insulate electricity. The compressible member may also be a member used for both sealing and insulating purposes.

[0091] [Insulated wire] The insulated wire of the present disclosure comprises a conductor and a coating layer disposed on the surface of the conductor and comprising the composition of the present disclosure. The coating layer is preferably a layer obtained by molding the composition of the present disclosure.

[0092] Insulated wires are suitable for LAN cables (Eathernet cables), high-frequency transmission cables, flat cables, heat-resistant cables, etc. In particular, insulated wires are suitable for transmission cables such as LAN cables (Eathernet cables) and high-frequency transmission cables.

[0093] Examples of conductor materials include metals such as copper and aluminum. The diameter of the conductor is, for example, 0.02 to 3 mm.

[0094] Specific examples of conductors include, for instance, AWG-46 (solid copper wire with a diameter of 40 micrometers), AWG-26 (solid copper wire with a diameter of 404 micrometers), AWG-24 (solid copper wire with a diameter of 510 micrometers), and AWG-22 (solid copper wire with a diameter of 635 micrometers).

[0095] The thickness of the coating layer is, for example, 0.1 to 3.0 mm.

[0096] Coaxial cables are an example of high-frequency transmission cables. Coaxial cables generally have a structure in which an inner conductor, an insulating coating layer, an outer conductor layer, and a protective coating layer are laminated in order from the core to the outer periphery. The molded article containing the copolymer of this disclosure can be suitably used as an insulating coating layer containing the copolymer. The thickness of each layer in the above structure is not particularly limited, but typically the inner conductor has a diameter of about 0.1 to 3 mm, the insulating coating layer has a thickness of about 0.3 to 3 mm, the outer conductor layer has a thickness of about 0.5 to 10 mm, and the protective coating layer has a thickness of about 0.5 to 2 mm.

[0097] Insulated wires may have another layer between the conductor and the insulation layer, and may also have yet another layer outside the insulation layer.

[0098] Insulated wires can be manufactured, for example, by extruding the composition of this disclosure onto a conductor in a molten state to form an insulating layer. [Examples]

[0099] The embodiments of this disclosure will now be described in detail with reference to examples, but the embodiments of this disclosure are not limited to these examples. In the following examples, Examples 1 to 5 are examples, and Examples 6 to 7 are comparative examples.

[0100] (Abbreviations for each monomer unit) PTFE: Polytetrafluoroethylene TFE: Tetrafluoroethylene PPVE: Perfluoro(propyl vinyl ether) AE-3000: 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether

[0101] (Content of each monomer unit) The content (mass%) of each unit in the composition obtained in each example is: 19 The molar ratio was calculated using a 1F nuclear magnetic resonance spectrometer (AVANCE-III-HD400, manufactured by Bruker Biospin), and the calculated molar ratio was then converted to mass ratio from the chemical structural formulas of each unit.

[0102] (MFR (Melt Flow Rate)) For each composition obtained in the example, a melt flow tester (Shimadzu Corporation "CFT-500EX") was used to measure the mass (g) of the molding material flowing out of an orifice with a diameter of 2.095 mm and a length of 8 mm in 10 minutes, in accordance with ASTM D1238, under conditions of a temperature of 372°C and a load of 5 kg, and this was defined as MFR (g / 10 min).

[0103] (Number of functional groups) The fluorinated compositions obtained in each example were hot-pressed at 330°C using a hydraulic press (SA-301, manufactured by Tester Industries Co., Ltd.) to produce sample films with a thickness of 0.25 to 0.30 mm. These sample films were scanned 40 times using a Fourier transform infrared spectrometer (FT-IR, Nicolet iS5, manufactured by ThermoScientific) to obtain infrared absorption spectra. Next, the above compositions were subjected to the fluorination treatment described below for a long period of time to prepare separate base samples that were completely fluorinated and free of functional groups. Base films were then prepared from each base sample in the same manner as above. The base films were analyzed using the method described above to obtain infrared absorption spectra (base spectra), and the difference spectrum between the infrared absorption spectrum of the sample films and the base spectrum of the base films was obtained. From the absorption peaks of the functional groups appearing in this difference spectrum, the main chain carbon number 10 of the fluorine-containing resin contained in the sample films was determined according to the following formula (A). 6 The number of functional cards N per individual was calculated. The correction factors used are as shown in Table 1 above. N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm)

[0104] (Melting point) The melting point (°C) of the composition was determined using a scanning differential thermal analyzer (NETZSCH DSC204F1 Phoenix) in an air atmosphere. 10-30 mg of the fluorinated composition obtained in each example was heated from 200°C to 350°C at a rate of 10°C / min, then cooled from 350°C to 200°C at a rate of 10°C / min, and finally heated again from 200°C to 350°C at a rate of 10°C / min. The melting point was determined from the temperature at which the maximum endothermic peak was observed.

[0105] [Example 1] (Preparation of Composition 1) A polymerization tank with a stirrer and an internal volume of 1.3 L was degassed, and then 625 g of CF3CH2OCF2CF2H (AE-3000: product name, manufactured by AGC), 417 g of water, 91.3 g of PPVE (343.9 mmol, amount of PPVE used at the start of polymerization), and 22.6 g of methanol were charged into the polymerization tank. Next, the temperature inside the polymerization tank was raised to 50°C (polymerization temperature), and 140 g of TFE (1405.2 mmol, amount of TFE used at the start of polymerization) was charged to raise the pressure inside the polymerization tank to 1.30 MPa (gauge pressure). 2 mL of a 0.06 mass% AE-3000 solution of heptafluorobutyroyl peroxide was charged as a polymerization initiator solution to start polymerization, and thereafter the polymerization initiator solution was continuously added. In addition, TFE was continuously charged so that the pressure during polymerization was maintained at the same level as the pressure at the start of polymerization. 43 mL of polymerization initiator solution was added, and 160 g of TFE was continuously charged. When 7.3 mol% of the PPVE used at the start of polymerization had been consumed, 28 g of TFE was added. The 28 g of TFE corresponds to 18.5 mol% of the total amount of PPVE and TFE used at the start of polymerization. The pressure in the polymerization vessel rose to 1.52 MPa (gauge pressure). TFE was continuously added to maintain the pressure during polymerization at the same level as the pressure at the start of polymerization. After adding 2 mL of polymerization initiator solution and continuously charging 10 g of TFE, the temperature in the polymerization vessel was lowered to 23°C, and the pressure in the polymerization vessel was purged until it reached 1 atm. The polymerization time was 300 minutes.

[0106] The obtained slurry was filtered to separate the polymerization medium, and then dried at 100°C for 15 hours to obtain the untreated copolymer. The composition of the untreated copolymer was TFE units / PPVE units = 96.2 / 3.8 (mass%).

[0107] Next, the untreated copolymer was subjected to a tray-type fluorination treatment using the following method. The untreated composition 1, placed in a special tray, was placed in a box-type reaction oven. The oven was then sealed and evacuated. Subsequently, an F2 / N2 mixed gas, prepared by diluting F2 gas with N2 gas to a concentration of 20% by volume, was introduced into the oven, filling it with the mixed gas. The pressure inside the oven was maintained at atmospheric pressure (1 atm), and the temperature at 230°C. The reaction was carried out for 120 minutes from the start of introduction of the mixed gas. After the reaction was complete, heating was stopped, and the F2 / N2 mixed gas in the oven was replaced with N2 gas. When the number of functional groups was calculated for composition 1, which was removed from the oven, according to the procedure described above, it was found to be less than 6. The MFR of composition 1 was 13.5 g / 10 min. The composition of the copolymer contained in composition 1 was identical to that of the untreated copolymer.

[0108] [Example 2] (Preparation of Composition 2) Initially, the amount of PPVE and methanol added to the polymerization tank were changed to 56.0 g and 20.2 g respectively. During polymerization, when 7.2 mol% of the PPVE used at the start of polymerization had been consumed, 28.8 g of TFE was added. 28.8 g of TFE corresponds to 20.3 mol% of the total amount of PPVE and TFE used at the start of polymerization. A copolymer with a composition of TFE units / PPVE units = 97.5 / 2.5 (mass%) was obtained in the same manner as in Example 1, except that 10.0 g of TFE was continuously added after the additional TFE was added to complete the polymerization. The polymerization time was 280 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare Composition 2, which had an MFR of 14.2 g / 10 min and fewer than 6 functional groups.

[0109] [Example 3] (Creation of Portrait 3) Initially, the amount of PPVE, methanol, and TFE added to the polymerization tank was changed to 87.9 g, 16.8 g, and 99.2 g respectively. During polymerization, when PPVE had been consumed at 10.3 mol% of the initial amount of PPVE used, 65.1 g of TFE was added. 65.1 g of TFE corresponds to 55.1 mol% of the total amount of PPVE and TFE used at the start of polymerization. A copolymer with a composition of TFE units / PPVE units = 94.3 / 5.7 (mass%) was obtained in the same manner as in Example 1, except that 4.0 g of TFE was continuously added after the additional TFE was added to complete the polymerization. The polymerization time was 370 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare composition 3, which had an MFR of 14.1 g / 10 min and fewer than 6 functional groups.

[0110] [Example 4] (Preparation of Composition 4) Initially, the amount of AE-3000, water, PPVE, methanol, and TFE added to the polymerization tank were changed to 846.1g, 270.0g, 115.7g, 7.5g, and 186.2g, respectively. During polymerization, when PPVE had been consumed at 5.4 mol% of the initial amount used, 48.4g of TFE was added. 48.4g of TFE corresponds to 23.0 mol% of the total amount of PPVE and TFE used at the start of polymerization. A copolymer with a composition of TFE units / PPVE units = 96.5 / 3.5 (mass%) was obtained in the same manner as in Example 1, except that 7.7g of TFE was continuously added after the additional TFE addition to complete the polymerization. The polymerization time was 260 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare composition 4, which had an MFR of 2.4g / 10min and fewer than 6 functional groups.

[0111] [Example 5] (Preparation of Composition 5) Initially, the amount of AE-3000, water, PPVE, methanol, and TFE added to the polymerization tank was changed to 841.9g, 272.5g, 119.6g, 5.2g, and 126.7g respectively. During polymerization, when 8.0 mol% of the PPVE used at the start of polymerization had been consumed, 97.5g of TFE was added. 97.5g of TFE corresponds to 61.5 mol% of the total amount of PPVE and TFE used at the start of polymerization. A copolymer with a composition of TFE units / PPVE units = 94.1 / 5.9 (mass%) was obtained in the same manner as in Example 1, except that 5.4g of TFE was continuously added after the additional TFE addition to complete the polymerization. The polymerization time was 290 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare composition 5, which had an MFR of 2.1g / 10min and fewer than 6 functional groups.

[0112] [Example 6] (Preparation of Composition 6) A copolymer with a composition of TFE units / PPVE units = 95.9 / 4.1 (mass%) was obtained in the same manner as in Example 1, except that no additional TFE was added. The polymerization time was 260 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare composition 6, which had an MFR of 13.9 g / 10 min and fewer than 6 functional groups.

[0113] [Example 7] (Preparation of Composition 7) In the same procedure as in Example 1, except that the amount of AE-3000 initially charged into the polymerization tank was changed to 843.9g, the amount of water to 270.0g, the amount of PPVE to 115.8g, the amount of methanol to 7.9g, and the amount of TFE to 186.0g, and no additional TFE was added, a copolymer with a composition of TFE units / PPVE units = 96.5 / 3.5 (mass%) was obtained. The polymerization time was 230 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to produce a copolymer with an MFR of 1.9g / 10min and fewer than 6 functional groups.

[0114] Next, for 100 parts of the copolymer after fluorination treatment, an average particle size of 500 μm and a specific gravity of 2.16 g / cm³ were obtained. 3Composition 7 was prepared by mixing 1.0 part of the PTFE powder in a vial and mixing it at 25°C for 15 hours using a roller-type shaker (IKA Corporation, device name "Rollar6basic"). The MFR of Composition 7 was 1.9 g / 10 min.

[0115] (Thermophysical property evaluation) - Heat of fusion - Using a scanning differential thermal analyzer (NETZSCH DSC204F1 Phoenix), the compositions obtained in each example were heated from 200°C to 350°C at a rate of 10°C / min under an air atmosphere. Subsequently, they were cooled from 350°C to 200°C at a rate of 10°C / min. When the mixture was heated again from 200°C to 350°C at a rate of 10°C / min, the peak area determined by drawing a straight line connecting the points where the melting curve deviates from the baseline and where it returns to the baseline around the melting peak was defined as the heat of fusion.

[0116] -Percentage A- The peak area was calculated from the curve between 315°C and 330°C and the straight line mentioned above, and the ratio A to the peak area representing the heat of fusion was calculated.

[0117] -Tilting T- The slope T of the straight line connecting the heat flow at 315°C and the heat flow at 320°C in the melting curve was calculated.

[0118] (Synovial fluid evaluation) -Ultrapure water contact angle- The compositions obtained in each example were hot-press molded at 330°C using a hydraulic press (SA-301, manufactured by Tester Industries Co., Ltd.) to produce sample films measuring 5 cm in length, 5 cm in width, and 1.0 mm in thickness. At arbitrary points on the sample film, approximately 2 μL of ultrapure water (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dropped onto the sample film at 25°C with the film fixed horizontally using a contact angle meter (SA-Co1, manufactured by Kyowa Interface Science Co., Ltd.) to measure the contact angle with the ultrapure water. This measurement was performed at five arbitrary points on the sample film, and the arithmetic mean was calculated.

[0119] -Urpure water drop angle- Using the contact angle meter described above, approximately 20 μL of ultrapure water was dropped onto the surface and tilted from 0° to 90° relative to the horizontal plane at a speed of 1° / second. The tilt angle at which the droplet began to slide downward, i.e., the fall angle, was measured. This was measured at five arbitrary points within the sample film, and the arithmetic mean was calculated.

[0120] -The rate at which ultrapure water falls- Using the contact angle meter described above, approximately 20 μL of ultrapure water was dropped onto the sample film while it was tilted to 50° relative to the horizontal plane. The maximum movement speed within the observation range after the droplet began to slide downwards was measured and defined as the falling velocity. This was measured at five arbitrary points within the sample film, and the arithmetic mean was calculated.

[0121] -The stability of ultrapure water falling- When the above-mentioned falling velocity was measured at five arbitrary points within the sample film, the slope of the movement velocity to the distance traveled was determined during observation of the droplet. The falling stability was determined based on the following criteria. If the slope of the movement velocity to the distance traveled is always positive, it indicates that the droplet is falling stably without a decrease in movement velocity.

[0122] A: At all five arbitrary measurement points, the slope of the droplet's velocity relative to its distance traveled is always positive. B: At one of any five measurement points, there exists a point where the slope of the droplet's velocity relative to its distance traveled is negative. C: At two or more of the five arbitrary measurement points, there are locations where the slope of the droplet's velocity relative to its distance traveled is negative.

[0123] The measurement and evaluation results are shown in Table 2. In Table 2, "Y" is indicated if the composition contains PTFE, and "N" is indicated if it does not contain PTFE.

[0124] [Table 2]

[0125] As shown in Table 2, Examples 1-5 demonstrated superior surface smoothness compared to Examples 6 and 7.

[0126] In Examples 1-5, the contact angle with ultrapure water exceeded 110° in all cases, which is equivalent to that of known PFAs, indicating that the water repellency is comparable to that of PFAs. The falling angle of ultrapure water is small when the above-mentioned ratio A is 1% or more. When the above-mentioned ratio A is 1% or more, the diameter of the spherulites generated in the molded product becomes smaller, and it is thought that the smoothness of the molded product surface is improved. As a result, the fine irregularities on the surface of the molded product are reduced, so that droplets of ultrapure water can fall even at a small angle. The falling velocity of ultrapure water is high when the above-mentioned ratio A is 1% or more. By a mechanism equivalent to that of the falling angle of ultrapure water, droplets of ultrapure water can be rapidly dropped from the surface of the molded product. The stability of ultrapure water droplets falling is high when the above-mentioned ratio A is 1% or more and the above-mentioned slope T is always positive. When the above-mentioned slope T is always positive, the diameter distribution of spherulites generated on the molded product also becomes smaller, and it is thought that there is less variation in the smoothness of the molded product surface. As a result, the size distribution of fine irregularities on the molded product surface becomes smaller, so ultrapure water droplets can be dropped from the molded product surface with high reproducibility and quickly.

Claims

1. A composition comprising a copolymer containing a tetrafluoroethylene-based structural unit and a perfluoro(alkyl vinyl ether)-based structural unit, The content of the tetrafluoroethylene-based constituent units is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer. The content of the perfluoro(alkyl vinyl ether)-based constituent units is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer. The melt flow rate measured under conditions of 372°C is 1.0 to 40.0 g / 10 min. In a melting curve observed by heating the composition from 200°C to 350°C at a rate of 10°C / min using a differential scanning calorimeter, the ratio A of the peak area representing the heat of fusion, determined by drawing a straight line connecting the points where the melting curve deviates from the baseline and where it returns to the baseline before and after the melting peak, to the peak area determined by the curve from 315°C to 330°C and the straight line is 1-20%, and the slope of the straight line connecting the heat flow at 315°C and the heat flow at 320°C is positive. composition.

2. The composition according to claim 1, wherein the perfluoro(alkyl vinyl ether) based structural unit includes a perfluoro(propyl vinyl ether) based structural unit.

3. The composition according to claim 1, wherein the melt flow rate measured under conditions of a temperature of 372°C is 1.0 to 19.0 g / 10 min.

4. The main chain number of carbon atoms of the copolymer is 10 ６ -CF = CF per unit ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ , and -CH ２ The composition according to claim 1, wherein the total number of functional groups selected from the group consisting of OH is 50 or less.

5. The composition according to claim 1, wherein the proportion A is 5 to 20%.

6. A molded article of the composition according to any one of claims 1 to 5.

7. The molded body according to claim 6, which is a tube, fitting, sheet, nut, tank, wire covering material, or member to be compressed.

8. A covered electric wire comprising a conductor and a coating layer disposed on the surface of the conductor and comprising the composition according to any one of claims 1 to 5.

9. The process involves using tetrafluoroethylene and perfluoro(alkyl vinyl ether) as raw materials, polymerizing them by solution polymerization, and producing a composition containing a copolymer that includes structural units based on tetrafluoroethylene and structural units based on perfluoro(alkyl vinyl ether). The content of the tetrafluoroethylene-based constituent units is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer. The content of the perfluoro(alkyl vinyl ether)-based constituent units is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer. The melt flow rate measured under conditions of 372°C is 1.0 to 40.0 g / 10 min. A method for producing a composition, comprising: adding tetrafluoroethylene at a rate of 15 to 65 mol% relative to the total amount of perfluoro(alkyl vinyl ether) and tetrafluoroethylene used at the start of polymerization, when the perfluoro(alkyl vinyl ether) has been consumed at a rate of 5 to 12 mol% relative to the amount of perfluoro(alkyl vinyl ether) used at the start of polymerization during the polymerization process.

10. A method for producing the composition according to claim 9, wherein the polymerization is carried out in a liquid medium containing a hydrofluoroether.

11. A method for producing the composition according to claim 10, wherein the hydrofluoroether is 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

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