Composition, molded body, coated electric wire, and method for producing composition

Abstract

A composition according to the present invention includes a copolymer that includes TFE units and PAVE units. The TFE units are 93.0–98.0 mass% of the total monomer units of the copolymer, and the PAVE units are 2.0–7.0 mass% of the total monomer units of the copolymer. The MFR of the composition is 1.0–40.0 g / 10 min. With respect to a melting curve observed when a differential scanning calorimeter is used to raise the temperature of the composition from 200°C to 350°C at 10°C / min, the percentage A of a peak area that represents the heat of fusion that is a peak area determined from the curve of the melting curve from 315°C to 330°C and a straight line is 1.0%–20.0%, and the slope of the straight line that connects the heat flow at 315°C and the heat flow at 320°C is positive.

Description

Composition, molded body, coated electric wire, and method for producing the composition

[0001] The present disclosure relates to a composition, a molded body, a coated electric wire, and a method for producing the composition.

[0002] As a fluororesin excellent in mechanical properties, chemical properties, electrical properties, etc. and capable of melt processing, a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PFA") is known. PFA is also excellent in heat resistance, chemical resistance, and purity.

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

[0004] Japanese Patent Laid-Open No. 7-70397

[0005] Netsu Sokutei, 38(3), p77-82

[0006] In the field of semiconductor manufacturing, as the miniaturization and integration of integrated circuits progress, the threshold value of the size regarded as a pattern defect is decreasing. One of the causes of defects is the contamination of chemical solutions with metal ions from the chemical solution supply system of semiconductor manufacturing equipment. The PFA molded body installed in the chemical solution supply system is also one of the sources of metal ions. One of the causes of metal contamination of the PFA molded body is the presence of irregularities on the surface of the PFA molded body. When irregularities exist on the surface of the PFA molded body, contaminants tend to stay in the irregularities. For example, Non-Patent Document 1 describes adding PTFE as a nucleating agent to refine spherulites. However, since the PTFE added as a nucleating agent itself becomes a contamination source, it is required to improve the smoothness of the surface of the PFA molded body 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 manufacturing the composition. Another embodiment of the present disclosure aims to solve the problem of providing a molded article using the above composition, and a coated electric wire.

[0008] 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, wherein the content of the tetrafluoroethylene-based structural unit 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 structural unit is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer, and the melt flow rate measured under conditions of a temperature of 372°C is 1.0 to 40.0 g / 10 min. A composition wherein, in a 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 by the curve from 315°C to 330°C and the straight line to the peak area indicating 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 1.0 to 20.0%, 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. <2> The composition according to claim 1, wherein the constituent units based on perfluoro(alkyl vinyl ether) include constituent units based on perfluoro(propyl vinyl ether). <3> The composition according to claim 1 or 2, 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 copolymer has a main chain with 10 carbon atoms. ６ -CF = CF per unit ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ , and -CH ２A composition according to any one of <1> to <3>, wherein the total number of functional groups selected from the group consisting of OH is 50 or less. <5> A composition according to any one of <1> to <4>, wherein the proportion A is 5.0 to 20.0%. <6> A molded article of the composition according to any one of <1> to <5>. <7> A molded article according to <6>, which is a tube, fitting, sheet, nut, tank, wire covering material, or a member to be compressed. <8> A covered wire comprising a conductor and a covering layer disposed on the surface of the conductor and containing the composition according to any one of <1> to <5>. <9> A method for producing a composition comprising using tetrafluoroethylene and perfluoro(alkyl vinyl ether) as raw materials, polymerizing them by a solution polymerization method, and producing a composition containing a copolymer having constituent units based on tetrafluoroethylene and constituent units based on perfluoro(alkyl vinyl ether), wherein the content of constituent units based on tetrafluoroethylene is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, the content of constituent units based on perfluoro(alkyl vinyl ether) 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 5 to 12 mol% of the perfluoro(alkyl vinyl ether) has been consumed during the polymerization relative to the amount of perfluoro(alkyl vinyl ether) used at the start of polymerization, tetrafluoroethylene is added in an amount of 15 to 65 mol% relative to the total amount of perfluoro(alkyl vinyl ether) and tetrafluoroethylene used at the start of polymerization. <10> A method for producing the composition according to <9>, wherein polymerization is carried out in a liquid medium containing a hydrofluoroether. <11> A method for producing the composition according to <10>, wherein the hydrofluoroether is 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

[0009] One embodiment of this disclosure aims to solve the problem of providing a composition that can produce a molded article with excellent surface smoothness, and a method for manufacturing the composition. Another embodiment of this disclosure aims to solve the problem of providing a molded article using the above composition, and a coated electric wire.

[0010] Figure 1 is a schematic diagram illustrating proportion A.

[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 the process is achieved. In this disclosure, numerical ranges indicated using "~" include the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in 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. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical 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" is a compound formed by the polymerization of monomers. That is, a "polymer" has multiple structural units. In this disclosure, “copolymer” 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” is a general term for an atomic group derived from one monomer molecule directly formed by the polymerization of monomers, and an atomic group obtained by chemically transforming a part of the above atomic group. In the following, as may be the case, 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 composition comprising a copolymer containing a tetrafluoroethylene-based structural unit and a perfluoro(alkyl vinyl ether)-based structural unit. The copolymer contained in the present disclosure has a content of tetrafluoroethylene-based structural units of 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, and a content of perfluoro(alkyl vinyl ether)-based structural units 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, when the composition is heated from 200°C to 350°C at a rate of 10°C / min using a differential scanning calorimeter, the melting curve observed is such that the ratio A of the peak area, which is determined by the curve from 315°C to 330°C and the straight line, to the peak area, which is determined by the straight line connecting the points where the melting curve deviates from the baseline and the points where it returns to the baseline around the melting peak, is 1.0 to 20.0%, and the slope of the straight line connecting the heat flow at 315°C and the heat flow at 320°C is positive.

[0014] The composition disclosed herein yields a molded article with excellent surface smoothness, particularly when the above-mentioned proportion A is 1.0 to 20.0% and the slope of the line connecting the heat flow at 315°C and the heat flow at 320°C is a positive value. The reason for this is not clear, but it is presumed to be 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 1.0 to 20.0%, 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 becomes smaller. 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 structure are significantly different. In this case, spherulites derived from PFA are formed from spherulites derived from the immiscible 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 surface smoothness may occur. The melting curve in differential scanning calorimetry when PTFE is added has two peaks in the heat of fusion. At this time, the slopes of the heat flow at 315°C and the heat flow at 320°C are negative because the peak of the heat of fusion derived from PTFE exists 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 is positive, does not have a peak in the amount of heat of fusion derived 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 composition described in Patent Document 1 contains 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 melting curve observed when the composition is heated from 200°C to 350°C at 10°C / min using a differential scanning calorimeter (DSC), the ratio A of the peak area determined by the curve from 315°C to 330°C and the straight line, which represents the amount of heat of fusion determined by drawing a straight line connecting the point where the melting curve deviates from the baseline and the point where it returns before and after the melting peak, is 1.0 to 20.0%.

[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 1.0 to 20.0% of the peak area indicating the heat of fusion.

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

[0023] When proportion A is 1.0% or more, the surface smoothness of the molded article is excellent due to the nucleating effect of copolymers with a high TFE unit content in the copolymer contained in the composition. When proportion A is 20.0% or less, the surface smoothness of the molded article is excellent because each component contained in the composition is easily miscible.

[0024] From the viewpoint of further improving the smoothness of the molded surface, the ratio A is preferably 1.0 to 20.0%, and more preferably 5.0 to 20.0%.

[0025] Methods for obtaining a composition in which proportion A is 1.0 to 20.0% include, for example, a dry blending method of copolymers having different TFE unit and PAVE unit contents with each other in powder or pellet form, a wet blending method of dispersions with each other, 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·°C)] = ("Heat flow value at 320°C" - "Heat flow value at 315°C") / 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·°C), and more preferably 0.0020 to 0.0150 mW / (mg·°C).

[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 1.0 g / 10 min or higher, the melt moldability is excellent. When the MFR is 40.0 g / 10 min or lower, the mechanical strength of the molded article is excellent.

[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 for adjusting the MFR of the copolymer to the above range is to adjust the molecular weight of the copolymer. The larger the molecular weight of the copolymer, the smaller the MFR. The MFR of the copolymer is measured in accordance with ASTM D1238, under conditions of a temperature of 372°C and a load of 5 kg, and represents the mass (g) of the copolymer flowing out of an orifice with a diameter of 2.095 mm and a length of 8 mm in 10 minutes. The copolymer and other components contained in the composition will be described in detail below.

[0034] [This copolymer] This copolymer contains TFE units and PAVE units. The TFE units are 93.0 to 98.0% by mass based on all the monomer units of the copolymer. The PAVE units are 2.0 to 7.0% by mass based on all the monomer units of the copolymer.

[0035] From the viewpoint of enhancing the strength of the molded body, the content of the TFE units is preferably 93.0% by mass or more, more preferably 93.5% by mass or more, and still more preferably 94.0% by mass or more based on all the monomer units of the copolymer. From the viewpoint of enhancing the flexibility of the molded body, the content of the TFE units is preferably 98.0% by mass or less, more preferably 97.5% by mass or less, and still more preferably 97.0% by mass or less based on all the monomer units of the copolymer.

[0036] From the viewpoint of enhancing the flexibility of the molded body, the content of the PAVE units is preferably 2.0% by mass or more, more preferably 2.5% by mass or more, and still more preferably 3.0% by mass or more based on all the monomer units contained in the copolymer. From the viewpoints of enhancing the crystallinity of the copolymer and enhancing the strength of the molded body, the content of the PAVE units is preferably 7.0% by mass or less, more preferably 6.5% by mass or less, and still more preferably 6.0% by mass or less based on all the monomer units contained in the copolymer.

[0037] As the PAVE, the monomer represented by the formula (1) is preferable. CF ２ =CF−O−Rf １ (1) In the formula (1), Rf １ [[ID=IS]] represents a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms of the perfluoroalkyl group represented by Rf １ 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. [[ID=1Y]]

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

[0039] In this copolymer, 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, the total content of TFE units and PAVE units is preferably 95.0% by mass or more, more preferably 98.0% by mass or more, even more preferably 99.0% by mass or more, and may be 100.0% by mass, relative to the total 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 TFE and PAVE units. Examples of other monomers include ethylene, vinylidene fluoride (VdF), hexafluoropropylene (HFP), and CX. １ X ２ = CX ３ (CF ２ ) ｎ X ４ (In the formula, X １ , X ２ , and X ３ Each of these independently represents either a hydrogen atom or a fluorine atom, X ４ ) represents a monomer, and CF ２ = CF - OCH ２ -Rf ２ (In the formula, Rf ２ ) represents a perfluoroalkyl group having 1 to 5 carbon atoms. Examples include monomers represented by ). When 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 contains only TFE units and PAVE units and does not contain units based on other monomers. 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 as follows: １９ It can be measured by known methods such as F-NMR (nuclear magnetic resonance analysis).

[0043] This copolymer is -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ , and -CH ２ The total number of specific functional groups selected from the group consisting of OH (hereinafter also referred to as "specific functional groups") (hereinafter also referred to as "number of 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. These specific functional groups are introduced into the copolymer, for example, by a chain transfer agent or polymerization initiator used in its production. More specifically, for example, when an alcohol is used as the chain transfer agent, or when -CH is used as the polymerization initiator. ２ When a peroxide having an OH structure is used, -CH is added to the main chain end of this copolymer. ２OH is introduced. Furthermore, by polymerizing monomers having functional groups, specific functional groups are introduced to the side chain ends of the copolymer. Also, if the number of functional groups in the copolymer having specific functional groups exceeds a predetermined range, the copolymer is fluorinated to remove the specific functional groups -CF ３ The number of functional groups can be reduced by converting them to 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 copolymer that is completely fluorinated and 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 is determined according to the following formula (A). ６ Calculate the number of functional groups N per individual.

[0046] N = I × K / t (A) I: Absorbance K: Correction factor 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]

[0049] Furthermore, in this copolymer, -CH ２ CF ２ H, -CH ２ COF, -CH ２ COOH, -CH ２ COOCH ３ , and -CH ２ CONH ２The absorption frequency is -CF shown in the table. ２ H, -COF, -COOH (free and bonded), -COOCH ３ , and -CONH ２ From each absorption frequency, several tens of kaiser (cm －１ ) becomes lower. For example, the number of -COF is -CF ２ The absorption frequency due to COF is 1883 cm⁻¹. －１ The number of functional groups determined from the absorption peak, and -CH ２ The absorption frequency due to COF is 1840 cm⁻¹. －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 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 bringing the melting point of this copolymer within the above range is to lower the polymerization temperature during the production of the 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 Components] 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 compositions of this disclosure contain 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 composition of this disclosure does not contain PTFE. If PTFE is included, it is preferable that it be 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 Producing 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 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 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 1.0 to 20.0%, 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 amount of TFE added 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 an F-nuclear magnetic resonance spectrometer (BRKer Biospin's "AVANCE-III-HD400"). The relationship between the amount of PAVE used and the molar ratio allows for the confirmation of PAVE consumption.

[0058] Adding TFE when PAVE consumption is 5 mol% or more allows for a relatively large proportion of TFE units in the copolymer produced after TFE addition. Adding TFE when PAVE consumption is 12 mol% or less prevents the proportion of copolymers with a relatively large proportion of TFE units in the copolymer produced after TFE addition from becoming too large, making it easier to control the composition of the copolymer produced through polymerization. From this viewpoint, 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 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 the predetermined time onward in which the proportion of TFE units is higher than the proportion of TFE units 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] Normally, 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 shows some degree of distribution. In contrast, in the method for producing the composition of this disclosure, the distribution is said to be larger because TFE is added later during polymerization. However, it is difficult to measure this distribution.

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

[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 to 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 at a temperature of 0 to 100°C, and more preferably a radical polymerization initiator with a temperature 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. 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.

[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 methoxynonanafluorobutane (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), ethoxynonanafluorobutane (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 HFE-449pc-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), 3-methoxy-4-trifluoromethyl-1,1,1,2,2,3,4,5,5,5-decafluoropentane (C ２ F ５ CF(OCH)３ ) CF (CF ３ ) CF ３ Examples include:

[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 a low content of metal elements, the content of metal elements in water is preferably 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 content of metal elements is preferably 0 ppb by mass or more. The method for achieving the above content of metal elements is not particularly limited, and examples include methods of reducing the content of metal elements by filtering water with various filters. The content of metal elements in water can be measured by the absolute calibration curve method using ICP-MS. The electrical conductivity of water is preferably 1.00 μS / cm or less, 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 metal elements in the water, and the electrical conductivity of water increases as the amount of metal elements increases. 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 relative to the total mass of the mixed solvent. The amount of polymerization medium used is preferably 3 times or more by mass relative to 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 relative to 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 relative to the amount of monomer used.

[0073] As chain transfer agents, 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 suitable from the viewpoint of having a large chain transfer constant and requiring a small amount of addition; hydrocarbons such as n-pentane, n-hexane, and cyclohexane; CF ２ H ２ Hydrofluorocarbons such as acetone; ketones such as methyl mercaptan; esters such as methyl acetate and ethyl acetate; and ethers such as diethyl ether and methyl ethyl ether are preferred. Among these, from the viewpoint of a higher chain transfer constant and higher stability of the terminal 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. As for alcohols, methanol or ethanol is preferred, and methanol is more preferred from the viewpoint of reactivity and availability. One type of chain transfer agent may be used alone, or two or more types may be used in combination. 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, 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. Polymerizability may be excellent at a polymerization temperature of 15°C or higher. The melting point of the copolymer may be improved at a polymerization temperature of 60°C or lower. The polymerization pressure is preferably 0.5 to 3.0 MPa, 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 Step] 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"). Fluorination treatment may result in the copolymer having -COOH, -COOCH ３ ien-CH ２ OH, -COF, -CF=CF ２ , -CONH ２ , and -CF ２ A specific functional group consisting of H, -CF ３ This allows for conversion to a specific functional group, making it easier to adjust the number of functional groups in this 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 source include F ２ Gas, N ２ F ２ and halogen fluorides (for example, IF ５ and CLF ３ Examples include:

[0079] F ２The concentration of fluorine radical sources such as gases may be 100% by volume. From a safety standpoint, F ２ It is preferable to use a mixed gas obtained by diluting the gas with an inert gas so that the gas concentration is 5 to 50 volume percent (preferably 15 to 30 volume percent). 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 of fluorination treatment include, for example, placing a shelf with the copolymer inside an oven and heating the inside of the oven with F ２ One method involves filling the column with gas or a gas mixture and heating it for a certain period of time. Another method involves heating a flow-through column packed with copolymer pellets while introducing F into the flow-through column. ２ Another method involves circulating a gas or a mixed gas for a certain period of time. The fluorination treatment time 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, and is, for example, 0.5 to 30 hours, with 1 to 24 hours being preferred.

[0082] [Molded Article] The molded article of the present disclosure is a molded article of the composition of the present disclosure. The molded article of the present disclosure is obtained by molding the composition of the present 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 among the molded articles of this disclosure. Injection-molded articles are also preferred because they can be obtained with a beautiful appearance without corroding the mold used for molding.

[0084] Furthermore, the form of the molded article of this disclosure may include, for example, pellets and powders. The molded article of this disclosure can be molded by conventionally known methods. As a method for molding the molded article, for example, a method may be used in which the composition is extruded while melting using a single-screw extruder, a twin-screw extruder, or a tandem extruder, and cut to a predetermined length to form 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 higher than the melting point of the composition. Conventionally known methods such as strand cutting, hot cutting, underwater cutting, and sheet cutting can be used for cutting the molded article. The volatile components in the pellets may be removed by heating the obtained pellets (degassing treatment). The obtained pellets may 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 applications: Food packaging films, lining materials for fluid transfer lines used in food manufacturing processes, packings, seals, sheets and other fluid transfer components for food manufacturing equipment; chemical stoppers, packaging films, lining materials for fluid transfer lines used in pharmaceutical manufacturing processes, packings, seals, sheets and other chemical liquid transfer components; internal lining members for chemical liquid 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 fuel transfer components such 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 automobile brake hoses, air conditioning hoses, radiator hoses and wire insulation materials; semiconductor 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, fuel cell carrier films, 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; and 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, 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 an insulated layer disposed on the surface of the conductor and comprising the composition of the present disclosure. The insulated layer is preferably a layer obtained by molding the composition of the present disclosure.

[0092] Insulated wires are suitable for LAN cables (Ethernet cables), high-frequency transmission cables, flat cables, heat-resistant cables, etc. In particular, insulated wires are suitable for transmission cables such as LAN cables (Ethernet 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 example, AWG (American Wire Gauge)-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.

[0099] The embodiments of the present disclosure will now be described in detail with reference to examples, but the embodiments of the present disclosure are not limited to these examples. In the following examples, Examples 1 to 5 are examples, and Examples 6 to 8 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 contained in the composition obtained in each example is: １９The molar ratio was calculated using an F-nuclear magnetic resonance spectrometer (BRKer Biospin's "AVANCE-III-HD400"), 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 molded 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 the MFR (g / 10 min).

[0103] (Number of Functional Groups) The fluorinated 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 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 above method 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 number of carbon atoms in the main chain of the fluorine-containing resin contained in the sample films was determined according to the following formula (A). ６ The number of functional groups 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 factor 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 to 30 mg of the fluorinated composition obtained in each example was used and 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 is degassed, and then CF ３ CH ２ OCF ２ CF ２ 625 g of H (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 vessel. Next, the temperature inside the polymerization vessel 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 vessel 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 the polymerization initiator solution was continuously added thereafter. In addition, TFE was continuously charged to maintain the pressure during polymerization 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, after which the oven was sealed and vacuumed. After that, F was placed inside the oven. ２ N ２ F, which is diluted with gas. ２ / N ２ A mixed gas was introduced, filling the oven with the above-mentioned mixed gas. The pressure inside the oven was maintained at atmospheric pressure (1 atm), and the temperature was maintained at 230°C. The reaction was allowed to proceed for 120 minutes from the start of the introduction of the mixed gas. After the reaction was complete, heating was stopped, and the F inside the oven was released. ２ / N ２ Mixed gas to N ２ When the number of functional groups in composition 1, which was removed from the oven after gas substitution, was calculated according to the procedure described above, it was found to be less than 6. Furthermore, the MFR of composition 1 was 13.5 g / 10 min. The copolymer composition in composition 1 was identical to that of the untreated copolymer.

[0108] [Example 2] (Preparation of Composition 2) The amount of PPVE initially charged into the polymerization tank was changed to 56.0 g and the amount of methanol to 20.2 g. 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. Except that 10.0 g of TFE was continuously charged after the additional TFE was added to complete the polymerization, the process was carried out in the same manner as in Example 1 to obtain a copolymer with a composition of TFE units / PPVE units = 97.5 / 2.5 (mass%). The polymerization time was 280 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare Composition 2 with an MFR of 14.2 g / 10 min and fewer than 6 functional groups.

[0109] [Example 3] (Preparation of Composition 3) The amount of PPVE initially charged into the polymerization tank was changed to 87.9 g, the amount of methanol to 16.8 g, and the amount of TFE to 99.2 g. During polymerization, when PPVE had been consumed at a rate of 10.3 mol% relative to the amount of PPVE used at the start of polymerization, 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. Except for the fact that 4.0 g of TFE was continuously charged after the additional TFE was added to complete the polymerization, the process was carried out in the same manner as in Example 1 to obtain a copolymer with a composition of TFE units / PPVE units = 94.3 / 5.7 (mass%). The polymerization time was 370 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare Composition 3 with an MFR of 14.1 g / 10 min and fewer than 6 functional groups.

[0110] [Example 4] (Preparation of Composition 4) The amount of AE-3000 initially charged into the polymerization tank was changed to 846.1 g, the amount of water to 270.0 g, the amount of PPVE to 115.7 g, the amount of methanol to 7.5 g, and the amount of TFE to 186.2 g. During polymerization, when PPVE had been consumed at 5.4 mol% of the amount of PPVE used at the start of polymerization, 48.4 g of TFE was added. 48.4 g 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 7.7 g of TFE was continuously charged after the additional TFE was added to complete the polymerization. The polymerization time was 260 minutes. Next, similar to Example 1, the untreated copolymer was fluorinated to prepare composition 4, which had an MFR of 2.4 g / 10 min and fewer than 6 functional groups.

[0111] [Example 5] (Preparation of Composition 5) The amount of AE-3000 initially charged into the polymerization tank was changed to 841.9 g, the amount of water to 272.5 g, the amount of PPVE to 119.6 g, the amount of methanol to 5.2 g, and the amount of TFE to 126.7 g. During polymerization, when 8.0 mol% of the amount of PPVE used at the start of polymerization had been consumed, 97.5 g of TFE was added. 97.5 g 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 5.4 g of TFE was continuously charged after the additional TFE was added to complete the polymerization. The polymerization time was 290 minutes. Next, similar to Example 1, the untreated copolymer was fluorinated to prepare composition 5, which had an MFR of 2.1 g / 10 min and fewer than 6 functional groups.

[0112] [Example 6] (Preparation of Composition 6) Except that no additional TFE was added, 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. The polymerization time was 260 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was fluorinated to prepare Composition 6 with an MFR of 13.9 g / 10 min and fewer than 6 functional groups.

[0113] [Example 7] (Preparation of Composition 7) The amount of AE-3000 initially charged into the polymerization tank was changed to 843.9 g, the amount of water to 270.0 g, the amount of PPVE to 115.8 g, the amount of methanol to 7.9 g, and the amount of TFE to 186.0 g. Except that no additional TFE was added, the preparation was the same as in Example 1 to obtain a copolymer with a composition of TFE units / PPVE units = 96.5 / 3.5 (mass%). The polymerization time was 230 minutes. Subsequently, the untreated copolymer was fluorinated in the same manner as in Example 1 to produce a copolymer with an MFR of 1.9 g / 10 min 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 used. 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 (manufactured by IKA Corporation, device name "Roller6basic"). The MFR of composition 7 was 1.9 g / 10 min.

[0115] [Example 8] (Preparation of Composition 8) 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 of Japanese Patent Application Publication No. Hei 8-73689. The polymerization time was 235 minutes. Subsequently, in the same manner as in Example 1, the untreated copolymer was subjected to fluorination treatment to prepare Composition 8 with an MFR of 2.8 g / 10 min and fewer than 6 functional groups.

[0116] (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.

[0117] -Ratio A- The peak area determined from the curve from 315°C to 330°C and the above straight line was calculated, and the ratio A of the peak area representing the heat of fusion was calculated.

[0118] -Slope 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.

[0119] (Synovial Fluid Evaluation) - Ultrapure Water Contact Angle - The 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 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 (manufactured by Kyowa Interface Science Co., Ltd., device name "SA-Co1"), and the contact angle with ultrapure water was measured. This was measured at five arbitrary points on the sample film, and the arithmetic mean was calculated.

[0120] - Ultrapure Water Drop Angle - Using the above contact angle meter, approximately 20 μL of ultrapure water was dropped onto the horizontal plane and tilted from 0° to 90° at a speed of 1° / second. The tilt angle at which the droplet began to slide downward, i.e., the drop angle, was measured. This was measured for five arbitrary points within the sample film, and the arithmetic mean was calculated.

[0121] - Ultrapure Water Dropping Velocity - Using the above contact angle meter, approximately 20 μL of ultrapure water was dropped onto the sample film with the film 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 dropping velocity. This was measured at five arbitrary points within the sample film, and the arithmetic mean was calculated.

[0122] - Rolling Stability of Ultrapure Water - When the rolling velocity was measured at five arbitrary points within the sample film, the slope of the moving velocity to the distance traveled was determined during observation of the droplets. The rolling stability was determined based on the following criteria. If the slope of the moving velocity to the distance traveled is always positive, it indicates that the droplets are rolling stably without a decrease in their moving velocity.

[0123] 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 the five arbitrary measurement points, 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, the slope of the droplet's velocity relative to its distance traveled is negative.

[0124] 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.

[0125]

[0126] As shown in Table 2, Examples 1 to 5 demonstrated superior surface smoothness compared to Examples 6, 7, and 8.

[0127] In Examples 1-5, the contact angle of ultrapure water exceeds 110° in all cases, which is equivalent to that of known PFA, indicating water repellency comparable to that of PFA. The rolling angle of ultrapure water is small when the above ratio A is 1.0% or more. When the above ratio A is 1.0% or more, the diameter of the spherulites generated on the molded product becomes smaller, and it is thought that the smoothness of the molded product surface improves. As a result, fine irregularities on the surface of the molded product are reduced, allowing ultrapure water droplets to fall even at small angles. The rolling velocity of ultrapure water is large when the above ratio A is 1.0% or more. By a mechanism similar to that of the rolling angle of ultrapure water, ultrapure water droplets can be quickly dropped from the surface of the molded product. The rolling stability of ultrapure water is high when the above ratio A is 1.0% or more and the above slope T is always positive. When the above slope T is always positive, the distribution of the diameter of the 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. This reduces the size distribution of fine irregularities on the surface of the molded product, allowing for highly reproducible and rapid dropping of ultrapure water droplets from the molded product surface.

[0128] Furthermore, the disclosure of Japanese Patent Application No. 2025-016299, filed on February 3, 2025, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated as being incorporated by reference.

Claims

1. A composition comprising a copolymer containing a tetrafluoroethylene-based structural unit and a perfluoro(alkyl vinyl ether)-based structural unit, wherein the content of the tetrafluoroethylene-based structural unit 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 structural unit is 2.0 to 7.0% by mass relative to the total monomer units of the copolymer, and the melt flow rate measured under conditions of 372°C is 1.0 to 40.0 g / 10 min. A composition wherein, in a 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 by the curve from 315°C to 330°C and the straight line to the peak area representing the heat of fusion, which is determined by connecting the points where the melting curve deviates from the baseline and the points where it returns to the baseline around the melting peak, is 1.0 to 20.0%, 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.

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 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 5.0 to 20.0%.

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 described in any one of claims 1 to 5.

9. A method for producing a composition comprising using tetrafluoroethylene and perfluoro(alkyl vinyl ether) as raw materials, polymerizing them by a solution polymerization method, and producing a composition containing a copolymer comprising constituent units based on tetrafluoroethylene and constituent units based on perfluoro(alkyl vinyl ether), wherein the content of constituent units based on tetrafluoroethylene is 93.0 to 98.0% by mass relative to the total monomer units of the copolymer, the content of constituent units based on perfluoro(alkyl vinyl ether) 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 the perfluoro(alkyl vinyl ether) has been consumed by 5 to 12 mol% of the amount of perfluoro(alkyl vinyl ether) used at the start of polymerization during the polymerization, tetrafluoroethylene is added 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.

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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