JP-2026075089-A - Method for manufacturing fluoropolymer molded articles

Abstract

[Problem] To provide a manufacturing method that can produce a fluoropolymer molded article in which the content of a fluorine-containing compound represented by the general formula: [C 5 F 11 COO - ] M + (wherein M + represents a cation) is reduced. [Solution] A method for producing a fluoropolymer molded article is provided, wherein the content of the hydrophilic fluorine-containing compound is reduced by heat-treating a molded article containing a fluoropolymer and a hydrophilic fluorine-containing compound at a temperature below the melting point of the fluoropolymer, wherein the molded article contains a fluoropolymer containing at least one fluorine-containing ether monomer unit selected from the group consisting of perfluorovinyl ether units and perfluoroallyl ether units, and the hydrophilic fluorine-containing compound is a fluorine-containing compound represented by the general formula: [C5F11COO- ] M + (wherein M + represents a cation). [Selection Diagram] None

Inventors

• 山本 有香里
• 村上 眞司
• 加藤 丈人
• 藤澤 学

Assignees

• ダイキン工業株式会社

Dates

Publication Date

20260507

Application Date

20251021

Priority Date

20241021

Claims (13)

1. A method for producing a fluoropolymer molded article, comprising heat-treating a molded article containing a fluoropolymer and a fluorine-containing compound having hydrophilic groups at a temperature below the melting point of the fluoropolymer, thereby producing a molded article in which the content of the fluorine-containing compound having hydrophilic groups is reduced, The molded article contains a fluoropolymer containing at least one fluorine-containing ether monomer unit selected from the group consisting of perfluorovinyl ether units and perfluoroallyl ether units, A method for producing a fluoropolymer molded article, wherein the fluorine-containing compound having the hydrophilic group is a fluorine-containing compound represented by the general formula: [C 5 F 11 COO - ] M + (wherein M + represents a cation).
2. The manufacturing method according to claim 1, wherein the molded body is an unused molded body.
3. The manufacturing method according to claim 1 or 2, wherein the molded body is heat-treated without being crushed.
4. The manufacturing method according to claim 1 or 2, comprising crushing the molded body and heat-treating the crushed molded body.
5. The manufacturing method according to claim 1 or 2, wherein the molded body is a molten molded body.
6. The manufacturing method according to claim 1 or 2, wherein the molded article is at least one selected from the group consisting of an extruded article, an injection-molded article, a blow-molded article, and a transfer-molded article.
7. The manufacturing method according to claim 1 or 2, wherein the molded body is a molten molded body, the molten molded body is crushed, and the crushed molded body is heat-treated.
8. The manufacturing method according to claim 1 or 2, wherein the temperature of the heat treatment is 150°C or higher.
9. The manufacturing method according to claim 1 or 2, wherein the heat treatment time is 1 second or more.
10. The manufacturing method according to claim 1 or 2, wherein the content of the fluorine-containing ether monomer units is 1.0 to 12.0% by mass.
11. The manufacturing method according to claim 1 or 2, wherein the fluoropolymer is a tetrafluoroethylene/fluorine-containing ether monomer copolymer and a tetrafluoroethylene/hexafluoropropylene/fluorine-containing ether monomer copolymer.
12. The manufacturing method according to claim 1 or 2, wherein the content of the fluorine-containing compound having hydrophilic groups in the molded article subjected to the heat treatment is 5 ppb by mass or more.
13. The manufacturing method according to claim 1 or 2, wherein the content of the fluorine-containing compound having the hydrophilic group in the molded article after heat treatment is less than 5 ppb by mass.

Description

This disclosure relates to a method for producing fluoropolymer molded articles. Patent Document 1 describes a method for producing recycled fluororesin, which includes a step of heat-treating a melt-molded used fluororesin molded product at a temperature of 200°C or higher but below its melting point. Japanese Patent Publication No. 2002-36237 The following describes specific embodiments of this disclosure in detail, but this disclosure is not limited to the embodiments described below. Patent Document 1 describes that recycled fluororesin can be produced using melt-molded used fluororesin molded products as raw materials and the above-described manufacturing method, thereby removing impurities such as chemical solutions and other substances to a degree equivalent to that of the fluororesin before use. However, depending on the molding conditions, fluoropolymer molded articles may contain fluorine-containing compounds represented by the general formula: [C 5 F 11 COO - ] M + (wherein M + represents a cation). In other words, the present disclosure is a method for producing a fluoropolymer molded article in which the content of the hydrophilic fluorine-containing compound is reduced by heat-treating a molded article containing a fluoropolymer and a hydrophilic fluorine-containing compound at a temperature below the melting point of the fluoropolymer, wherein the molded article contains a fluoropolymer containing at least one fluorine-containing ether monomer unit selected from the group consisting of perfluorovinyl ether units and perfluoroallyl ether units, and the hydrophilic fluorine-containing compound is a fluorine-containing compound represented by the general formula: [C 5 F 11 COO - ]M + (wherein M + represents a cation). Next, the manufacturing method of this disclosure will be described in more detail. (A molded article containing a fluorine-containing compound having a hydrophilic group) The molded article subjected to heat treatment in the manufacturing method of this disclosure contains a fluorine-containing compound having a hydrophilic group. The hydrophilic groups of fluorine-containing compounds are preferably anionic groups such as acidic groups, for example, -NH₂ , -PO₃M , -OPO₃M , -SO₃M , -OSO₃M , and -COOM (where M represents a cation in each formula). Among the above hydrophilic groups, -SO₃M or -COOM are preferred, and -COOM is more preferred. Examples of cations include H⁺ , ammonium ions, alkali metal ions, and alkaline earth metal ions. In one embodiment, the molded article subjected to heat treatment contains a fluorine-containing compound having a hydrophilic group, which is represented by the following general formula. General formula: [C 5 F 11 COO − ]M + (In the formula, M + represents a cation.) The content of the compound represented by the general formula: [C 5 F 11 COO - ]M + in the molded article subjected to heat treatment may be 5 ppb or more by mass, 15 ppb or more by mass, 25 ppb or more by mass, 30 ppb or more by mass, 35 ppb or more by mass, 40 ppb or more by mass, 45 ppb or more by mass, or 50 ppb or more by mass, and may be 1000 ppb or less by mass, or 500 ppb or less by mass. In one embodiment, the molded article subjected to heat treatment contains a fluorine-containing compound having a hydrophilic group, which is represented by the following general formula. General formula: [C n-1 F 2n-1 COO - ]M + (In the formula, n is an integer between 8 and 14, and M + represents a cation.) The content of the compound represented by the general formula: [C n-1 F 2n-1 COO - ] M + (wherein n is an integer from 8 to 14, and M + represents a cation) in a molded article subjected to heat treatment may be 1 ppb by mass or more, 2 ppb by mass or more, 3 ppb by mass or more, 4 ppb by mass or more, or 5 ppb by mass or more, and may be 1000 ppb by mass or less, or 500 ppb by mass or less. n may be an integer from 9 to 14. In one embodiment, the molded article subjected to heat treatment contains a fluorine-containing compound having a hydrophilic group, which is represented by the following general formula. General formula: [C n-1 F 2n-1 COO - ]M + (In the formula, n is an integer between 11 and 14, and M + represents a cation.) The molded article subjected to heat treatment contains a compound represented by the general formula: [C n-1 F 2n-1 COO - ] M + (wherein n is an integer from 11 to 14, and M + represents a cation) which may be 1 ppb by mass or more, 2 ppb by mass or more, 3 ppb by mass or more, 4 ppb by mass or more, or 5 ppb by mass or more, and may be 1000 ppb by mass or less, or 500 ppb by mass or less. In one embodiment, the molded article subjected to heat treatment contains a fluorine-containing compound having a hydrophilic group, which is represented by the following general formula (H1). General formula (H1): [X-Rf-A − ] i M i+ (In the formula, X is H, Cl, Br, F, or I; Rf is a partially fluorinated or fully fluorinated aliphatic group of a linear or branched chain