Method for manufacturing fluororesin molding materials, method for manufacturing fluororesin molded articles, molding materials and molded articles

Abstract

The present invention provides a manufacturing method for regenerating fluororesin molding material from fluororesin molded articles, which enables the smooth production of molded articles having a desired shape while suppressing the occurrence of molding defects and without impairing the excellent properties inherent in fluororesin. [Solution] A method for producing a fluororesin molding material (II) is provided, which involves using a fluororesin molded article (I) formed from a fluororesin that has undergone two or more melt shear treatments performed above the melting point of the fluororesin as a raw material, and performing a melt shear treatment, wherein the melt flow rate (MFR) change rate calculated by the calculation formula described in the specification is within the range of -15% to +15%.

Description

[Technical Field]

[0001] This disclosure relates to a method for manufacturing a fluororesin molding material, a method for manufacturing a fluororesin molded article, a molding material, and a molded article. [Background technology]

[0002] 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. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-36237 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure aims to provide a manufacturing method for regenerating fluororesin molding material from fluororesin molded articles, which enables the smooth production of fluororesin molding material having a desired shape while suppressing the occurrence of molding defects and without impairing the excellent properties inherent in fluororesin. [Means for solving the problem]

[0005] According to this disclosure, a method for producing a fluororesin molding material (II) is provided, which involves using a fluororesin molded article (I) formed from a fluororesin that has undergone two or more melt shear treatments performed above the melting point of the fluororesin as a raw material, and performing a melt shear treatment, wherein the melt flow rate (MFR) change rate is within the range of -15% to +15%. MFR change rate (%) = log 10 (A / B) × 100 A: MFR (g / 10 min) of fluoropolymer molding material (II) at 372°C B: MFR (g / 10 min) of the fluororesin molded body (I) at 372 °C

Advantages of the Invention

[0006] According to the present disclosure, there is provided a manufacturing method for recycling a fluororesin molding material from a fluororesin molded body, which can smoothly manufacture a molded body having a desired shape without impairing the excellent properties inherent to the fluororesin while suppressing the occurrence of molding defects, and can provide a manufacturing method capable of manufacturing a fluororesin molding material.

Embodiments for Carrying Out the Invention

[0007] <​​​​​​​​​​​​​​Patent Document 1 describes a manufacturing method for producing recycled fluororesin using melt-molded used fluororesin molded products as raw materials. The recycled fluororesin produced by the manufacturing method described in Patent Document 1 is a pulverized material obtained by crushing the molded product using a pulverizer, and the shape of the pulverized material is chip-like with a particle size of 0.5 to 10 mm. It has become clear that molding defects are likely to occur when such pulverized material is molded using a screw-type molding machine. The reason for this is presumed to be that because such pulverized material is of uneven size, it is difficult to stably engage with the screw, and the melting state in the cylinder becomes uneven, making discharge from the nozzle or extrusion die provided at the tip of the cylinder unstable. Therefore, in order to suppress molding defects, there is a need for a manufacturing method that can produce recycled fluororesin with uniform size.

[0011] The inventors focused on a manufacturing method that utilizes melt shear treatment as a method for producing fluororesin molding materials of uniform size using a fluororesin molded article (I) as a raw material. However, it became clear that simply using melt shear treatment significantly alters the melt flow rate (MFR) of the fluororesin, impairing the excellent properties (for example, high tensile strength and large tensile elongation) that the raw material fluororesin originally possessed.

[0012] This disclosure provides a manufacturing method that brilliantly solves these problems, and is a method for manufacturing a fluororesin molding material (II) by performing a melt shear treatment on a fluororesin molded article (I) formed from a fluororesin that has undergone two or more melt shear treatments performed above the melting point of the fluororesin as a raw material.

[0013] Next, the manufacturing method of this disclosure will be described in more detail.

[0014] In the manufacturing method of this disclosure, a fluororesin molding material (II) is produced by performing a melt shear treatment using a fluororesin molded article (I) as a raw material. In this process, by keeping the rate of change of the melt flow rate (MFR) between the fluororesin molded article (I) and the fluororesin molding material (II) within the range of -15% to +15%, a fluororesin molding material can be produced that allows for the smooth manufacture of molded articles having a desired shape without impairing the excellent properties inherent in the fluororesin.

[0015] The MFR change rate is calculated using the following formula. MFR change rate (%) = log 10 (A / B) × 100 A: MFR (g / 10 min) of fluoropolymer molding material (II) at 372°C B: MFR (g / 10 min) of fluoropolymer molded article (I) at 372°C

[0016] In this disclosure, MFR is a value obtained in accordance with ASTM D1238 as the mass (g / 10 min) of polymer flowing out of a nozzle with an inner diameter of 2.1 mm and a length of 8 mm per 10 minutes using a melt indexer at 372°C and a load of 5 kg.

[0017] The range of the MFR change rate is preferably -15% or more at the lower limit, more preferably -10% or more, even more preferably -6% or more, and most preferably -3% or more at the upper limit, preferably +15% or less, more preferably +10% or less, even more preferably +6% or less, and most preferably +3% or less.

[0018] In one embodiment, the fluororesin molded article (I) includes a molded article having a shape that is difficult to treat by melt shearing using a screw-type molding machine.

[0019] In this disclosure, a screw-type molding machine is a molding machine equipped with a screw, which typically rotates the screw to apply a melting shear force to the fluororesin material, and continuously transfers the fluororesin material from a material supply port provided in the cylinder to a nozzle or extrusion die installed at the tip of the cylinder, thereby molding the fluororesin material.

[0020] "Molded bodies with shapes that make melt shearing difficult using screw-type molding machines" refers to molded bodies that are too small to reach the screw portion of a molding machine equipped with a screw, making it impossible to apply the machine, or molded bodies that, even when fed into the cylinder of a molding machine equipped with a screw and the screw is rotated, are difficult to grip with the screw and cannot be stably transported to the tip of the cylinder. Raw materials containing such molded bodies are difficult to supply into the cylinder, and even if they are supplied and melted in the cylinder, the molten fluororesin is discharged from the nozzle or extrusion die with no or insufficient melt shear force applied to a portion of it, which can cause molding defects.

[0021] The manufacturing method of the present disclosure involves performing a melt shear treatment while adjusting the MFR change rate (%) within the above-described range. Therefore, by using the manufacturing method of the present disclosure, even when a molded body having a shape that is difficult to perform melt shear treatment using a screw-type molding machine is used as a raw material, a fluororesin molding material (II) having a shape that can be easily molded by melt shear treatment using a screw-type molding machine can be manufactured. Moreover, by using the fluororesin molding material (II) obtained by the manufacturing method of the present disclosure, it is possible to smoothly manufacture a molded body having a desired shape without impairing the excellent properties inherent in the fluororesin, while suppressing the occurrence of molding defects.

[0022] In one embodiment, the fluororesin molded article (I) includes a molded article having a maximum length of 15 mm or more. Such a long molded article may not reach the screw when fed into a molding machine equipped with a screw, or even if it reaches the screw and the screw is rotated, it may not easily get caught in the screw, making it impossible to apply any or sufficient molten shear force. The maximum length is the maximum length of the line segment connecting two points on the surface of the molded article. For example, if the molded article is a rectangular parallelepiped, the maximum length is the length of the diagonal of the rectangular parallelepiped. For example, if the molded article is an ellipsoid, the maximum length is the length of the major axis of the ellipsoid.

[0023] In one embodiment, the fluororesin molded article (I) includes a sprue or runner. Since the sprue or runner usually has an elongated shape, even if it is fed into a molding machine equipped with a screw, it may not reach the screw, or even if it reaches the screw and the screw is rotated, it may not easily get caught in the screw and cannot be conveyed forward, so a melt shear force cannot be applied at all or insufficiently.

[0024] In one embodiment, the fluororesin molded article (I) includes scraps generated during the manufacture of extruded articles such as tubes. Extruded articles that are pushed out of the extrusion die immediately after the start of extrusion molding may have defects such as inconsistent shape and are usually excluded from the product. Since the excluded extruded articles usually include those with an elongated shape, they may not reach the screw even when fed into a molding machine equipped with a screw, or even if they reach the screw and the screw is rotated, they may not easily get caught in the screw and cannot be conveyed forward, so no or sufficient molten shear force can be applied.

[0025] In one embodiment, the fluororesin molded article (I) includes a resin ball. A "resin ball" is a lump formed from a molded article that does not have product value. Since resin balls usually have a relatively large shape, even if they are fed into a molding machine equipped with a screw, they cannot reach the screw and therefore cannot be subjected to melt shearing treatment.

[0026] In one embodiment, the fluororesin molded article (I) includes pulverized material. Because the pulverized material is of uneven size, it is difficult to stably engage with the screw, and the melting state within the cylinder becomes uneven. This makes it easy for the material to be discharged from the nozzle or extrusion die at the tip of the cylinder to become unstable, which can cause molding defects, making it difficult to use directly for molding products.

[0027] In one embodiment, a fluororesin molded material (II) is produced by mixing a fluororesin molded article (I) with a virgin polymer and then performing a melt shear treatment. The mass ratio of the fluororesin molded article (I) to the virgin polymer may be, for example, 1:99 to 99:1, preferably 5:95 to 95:5, and more preferably 10:90 to 90:10. In one embodiment, the mass ratio of the fluororesin molded article (I) to the virgin polymer may be 99:1 to 100:0, and at 100:0, i.e., the fluororesin molded material (II) may be subjected to melt shear treatment alone without mixing it with the virgin polymer. Even when a virgin polymer is mixed, the MFR change rate can be controlled within the above range by appropriately setting the mass ratio and melt shear treatment conditions.

[0028] As the virgin polymer, a melt-processable fluororesin of the same type as the fluororesin forming the fluororesin molded article (I) or a different type can be used. When using the same type of fluororesin, the monomer composition of the polymer forming the fluororesin molding material (II) can be adjusted, or the physical properties of the fluororesin molding material (II), such as the melt flow rate, can be adjusted.

[0029] By using the manufacturing method of the present disclosure, a fluororesin molding material (II) with uniform size can be manufactured. Therefore, by using the fluororesin molding material (II) manufactured by the manufacturing method of the present disclosure, it is possible to smoothly manufacture a molded article having a desired shape while suppressing the occurrence of molding defects.

[0030] Specific examples of fluoropolymer molded articles (I) include molded articles other than pellets, such as scraps and waste materials generated during the manufacture of fluoropolymer molded articles, and used fluoropolymer molded articles. Examples of scraps and waste materials include: defective products resulting from molding fluoropolymers; sprues and runners generated during injection molding of fluoropolymers; waste materials generated from edge trimming and punching of fluoropolymer molded products; and waste materials generated from the start of molding until the shape of the extruded product stabilizes when manufacturing molded products such as sheets, tubes, and electric wires by extrusion molding of fluoropolymers. Examples of used fluoropolymer molded articles include sheets, tubes, fittings, sealants, films, bottles, and wafer carriers. These may have been used in high-temperature environments, in contact with water or chemicals, or outdoors. If the used molded articles are contaminated, they may be cleaned with a cleaning solution, dried, and used as fluoropolymer molded articles (I).

[0031] The manufacturing method disclosed herein can also be used to repeatedly regenerate fluororesins. That is, molded articles manufactured using fluororesin molding material (II) manufactured by the manufacturing method disclosed herein can also be reused as raw materials (fluororesin molded article (I)) in the manufacturing method disclosed herein. By using the manufacturing method disclosed herein, fluororesin molding material (II) can be manufactured without impairing the excellent properties inherent in the fluororesin, even when the same fluororesin is repeatedly regenerated.

[0032] The fluororesin used to form the fluororesin molded article (I) is melt-processable, and is typically a melt-processable fluororesin. Melt-processability means that the polymer can be melted and processed using conventional processing equipment such as extruders and injection molding machines.

[0033] The melt flow rate (MFR) of the fluororesin molded article (I) is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, even more preferably 1.0 g / 10 min or more, still more preferably 3.0 g / 10 min or more, particularly preferably 10.0 g / 10 min or more, most preferably 15.0 g / 10 min or more, preferably 100.0 g / 10 min or less, more preferably 90.0 g / 10 min or less, still more preferably 80.0 g / 10 min or less, still more preferably 70.0 g / 10 min or less, and particularly preferably 50.0 g / 10 min or less. The MFR of the fluororesin molded article (I) is the same as the MFR of the fluororesin forming the fluororesin molded article (I), provided that the fluororesin molded article (I) does not contain any components other than fluororesin, to the extent that it affects the MFR.

[0034] The fluororesin used to form the fluororesin molded article (I) preferably has functional groups. By selecting a fluororesin molded article (I) formed from a fluororesin having functional groups as the raw material, the MFR change rate can be easily adjusted within the above-mentioned range, and therefore, a fluororesin molding material can be manufactured without impairing the excellent properties inherent in the fluororesin.

[0035] Functional groups are functional groups located at the ends of the main chain or side chains of the copolymer, and functional groups located within the main chain or side chains. Preferably, the functional group is at least one selected from the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH, more preferably -COF, -COOH, and -CH2OH, and even more preferably -CH2OH.

[0036] The number of functional groups in the fluororesin that forms the fluororesin molded article (I) is 10 carbon atoms in the main chain. 6The number of functional groups per unit is preferably 1 or more, more preferably 6 or more, even more preferably 10 or more, still more preferably 20 or more, and particularly preferably 30 or more. There is no particular upper limit, but it may be 700 or less. The number of functional groups may be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0037] In one embodiment, the fluororesin used to form the fluororesin molded article (I) has at least one functional group selected from the group consisting of -CH2OH, -COF, and -COOH. By selecting a fluororesin molded article (I) formed from a fluororesin having these functional groups as a raw material, the MFR change rate can be easily adjusted to the above range, and therefore, a fluororesin molding material can be manufactured without impairing the excellent properties inherent in the fluororesin.

[0038] If the fluororesin forming the fluororesin molded article (I) has at least one functional group selected from the group consisting of -CH2OH, -COF, and -COOH, the total number of -CH2OH, -COF, and -COOH is 10 carbon atoms in the main chain. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, and especially preferably 30 or more. There is no particular upper limit, but it may be 500 or less.

[0039] In one embodiment, the fluororesin used to form the fluororesin molded article (I) has -COF and -COOH. By selecting a fluororesin molded article (I) formed from a fluororesin having these functional groups as a raw material, the MFR change rate can be easily adjusted to the above range, and therefore, a fluororesin molding material can be manufactured without impairing the excellent properties inherent in the fluororesin.

[0040] If the fluororesin forming the fluororesin molded article (I) has -COF and -COOH, the total number of -COF and -COOH is 10 carbon atoms in the main chain. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably more than 6, even more preferably 10 or more, particularly preferably 20 or more, most preferably 30 or more, and there is no upper limit, but it may be 500 or less or 300 or less.

[0041] In one embodiment, the fluororesin used to form the fluororesin molded article (I) contains -CH2OH. By selecting the fluororesin molded article (I) formed from a fluororesin containing -CH2OH as the raw material, the MFR change rate can be easily adjusted to within the above range, and therefore, a fluororesin molding material can be manufactured without impairing the excellent properties inherent in the fluororesin.

[0042] When the fluororesin forming the fluororesin molded article (I) has -CH2OH, the number of -CH2OH is 10 carbon atoms in the main chain. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, and especially preferably 30 or more. There is no particular upper limit, but it may be 500 or less.

[0043] Infrared spectroscopy can be used to identify the types of functional groups and measure their number.

[0044] The number of functional groups is specifically measured by the following method. First, the copolymer is molded by cold pressing 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, and a difference spectrum is obtained from this spectrum to the base spectrum where the copolymer is completely fluorinated and no functional groups are present. From the absorption peak of a specific functional group appearing in this difference spectrum, the number of carbon atoms in the copolymer (1 × 10) is calculated according to the following formula (A). 6Calculate the sensory group number N per piece.

[0045] N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm)

[0046] For reference, absorption frequencies, molar absorption coefficients, and correction coefficients for several functional groups are shown in Table 1. The molar absorption coefficient was determined from FT-IR measurement data of low molecular weight model compounds.

Table 1

[0047] The absorption frequencies of -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are several tens of wavenumbers (cm -1 ) lower than the absorption frequencies of -COF, -COOH free and -COOH bonded, -COOCH3, and -CONH2 shown in the table, respectively.

[0048] [[ID=2,9]] For example, the number of functional groups of -COF is the sum of the number of functional groups determined from the absorption peak of the absorption frequency of -1 1883 cm due to -CF2COF and the number of functional groups determined from the absorption peak of the absorption frequency of -1 1840 cm due to -CH2COF.

[0049] The above functional groups are introduced into the copolymer, for example, by a chain transfer agent or a polymerization initiator used in the production of the copolymer. For example, when an alcohol is used as a chain transfer agent or a peroxide having a -CH2OH structure is used as a polymerization initiator, -CH2OH is introduced into the main chain end of the copolymer. In addition, by polymerizing a monomer having a functional group, the above functional group is introduced into the side chain end of the copolymer.

[0050] ​​​​There are no particular limitations on the method used for the molten shear treatment, and conventionally known methods can be used. For example, a screw-type extrusion machine or a screw-type injection molding machine can be used for the molten shear treatment.

[0051] The melt shearing temperature is preferably 390°C or lower, more preferably 385°C or lower, and even more preferably 380°C or lower. By setting the melt shearing temperature within the above range, the MFR change rate can be easily adjusted to within the above range, and therefore, fluororesin molding materials can be manufactured without impairing the excellent properties inherent in the fluororesin. The melt shearing temperature is usually the set temperature of the cylinder in the melting zone of the molding machine used for the melt shearing. When using a resin with high viscosity, the set temperature of the die portion may be set higher than the set temperature of the cylinder in the melting zone to prevent the occurrence of melt fracture, for example, it may be higher than 390°C. Furthermore, the melt shearing temperature is preferably the melting point of the fluororesin + 85°C or lower, more preferably the melting point of the fluororesin + 80°C or lower, and even more preferably the melting point of the fluororesin + 75°C or lower.

[0052] The temperature of the molten shear treatment is preferably 355°C or higher, and more preferably 360°C or higher. By setting the temperature of the molten shear treatment within the above range, fluororesin material (II) can be efficiently manufactured, and the MFR change rate can be easily adjusted within the above range. Therefore, fluororesin molding materials can be manufactured without impairing the excellent properties inherent in the fluororesin. The temperature of the molten shear treatment is usually the set temperature of the cylinder in the melting zone of the molding machine used for the molten shear treatment. The temperature of areas other than the melting zone, such as the feed zone, may be lower than 355°C. Furthermore, the temperature of the molten shear treatment is preferably the melting point of the fluororesin + 55°C or higher, and more preferably the melting point of the fluororesin + 50°C or higher.

[0053] From the viewpoint of making it easier to adjust the MFR change rate within the above range, it is preferable to select a fluororesin molded article (I) formed from a functional fluororesin as the raw material, and to adjust the temperature of the melt shear treatment within the above range.

[0054] The inside of the extruder may be kept in an atmosphere with added air, oxygen, nitrogen, etc., to remove volatile components. It may also have a vent, be open, or have a vent to reduce pressure.

[0055] In one embodiment, the molten shear treatment is carried out substantially in the absence of water. In one embodiment, the fluororesin molded article (I) subjected to the molten shear treatment substantially contains no water. In one embodiment, the water content in the fluororesin molded article (I) subjected to the molten shear treatment is preferably 1.00% by mass or less, more preferably 0.50% by mass or less, even more preferably 0.30% by mass or less, may be 0% by mass or more, and preferably 0.01% by mass or more. In one embodiment, the fluororesin molded article (I) subjected to the molten shear treatment does not contain an amount of water exceeding the water content in the air. By refraining from actively supplying water to the fluororesin molded article (I) or the extruder, corrosion of metal parts constituting the extruder, such as cylinders, can be suppressed, and the incorporation of metal into the fluororesin molding material can be prevented. Furthermore, according to the manufacturing method of this disclosure, even when the molten shear treatment is carried out without actively supplying water, a colorless fluororesin molding material (II) can be produced.

[0056] In one embodiment, by selecting a fluororesin molded article (I) formed from a fluororesin having functional groups as the raw material, and setting the melt shear treatment temperature to 360-390°C, more preferably 360-385°C, and even more preferably 360-380°C, the MFR change rate can be more easily adjusted to the above range, and therefore, fluororesin molding materials can be manufactured more efficiently without impairing the excellent properties inherent in the fluororesin. The number of functional groups is 10 carbon atoms in the main chain. 6The number of functional groups per unit is preferably 1 or more, more preferably 6 or more, even more preferably 10 or more, still more preferably 20 or more, and particularly preferably 30 or more. There is no particular upper limit, but it may be 700 or less. The number of functional groups may be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0057] The reason why the MFR change rate can be more easily adjusted within the above range by selecting a fluororesin with functional groups and controlling the temperature of the melt shear treatment is presumed to be as follows: During the melt shear treatment, which is performed at high temperatures, the main chain of the fluororesin is broken, but if the fluororesin has functional groups, the main chain of the fluororesin is also extended simultaneously by bonding between the functional groups. If the melt shear treatment temperature is too high, the breaking of the main chain of the fluororesin tends to take precedence, but it is presumed that by appropriately controlling the melt shear treatment temperature, the breaking and extension of the main chain of the fluororesin can be carried out in a balanced manner while maintaining the high productivity of the fluororesin molding material.

[0058] From the viewpoint of achieving a more balanced progression between the cleavage and elongation of the main chain of the fluororesin, it is preferable to appropriately control the melt shearing temperature and to appropriately select the type and number of functional groups. Particularly preferred embodiments are as follows.

[0059] In one embodiment, by selecting a fluororesin molded article (I) formed from a fluororesin having at least one functional group selected from the group consisting of -CH2OH, -COF, and -COOH as the raw material, and by setting the melt shear treatment temperature to 360-390°C, more preferably 360-385°C, and even more preferably 360-380°C, the MFR change rate can be more easily adjusted to the above range, and therefore, fluororesin molding materials can be manufactured more efficiently without impairing the excellent properties inherent in the fluororesin. The total number of -CH2OH, -COF, and -COOH is 10 carbon atoms in the main chain. 6Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, and especially preferably 30 or more. There is no particular upper limit, but it may be 500 or less.

[0060] In one embodiment, by selecting a fluororesin molded article (I) formed from a fluororesin having -COF and -COOH as the raw material, and setting the melt shear treatment temperature to 360-390°C, more preferably 360-385°C, and even more preferably 360-380°C, the MFR change rate can be more easily adjusted to the above range, and therefore, fluororesin molding materials can be manufactured more efficiently without impairing the excellent properties inherent in the fluororesin. The total number of -COF and -COOH is 10 carbon atoms in the main chain. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably more than 6, even more preferably 10 or more, particularly preferably 20 or more, most preferably 30 or more, and there is no upper limit, but it may be 500 or less or 300 or less.

[0061] In one embodiment, by selecting a fluororesin molded article (I) formed from a fluororesin having -CH2OH as the raw material, and setting the melt shear treatment temperature to 360-390°C, more preferably 360-385°C, and even more preferably 360-380°C, the MFR change rate can be more easily adjusted to the above range, and therefore, fluororesin molding materials can be manufactured more efficiently without impairing the excellent properties inherent in the fluororesin. The number of -CH2OH is the number of carbon atoms in the main chain (10 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, and especially preferably 30 or more. There is no particular upper limit, but it may be 500 or less.

[0062] As the fluororesin used to form the fluororesin molded article (I), at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymer and tetrafluoroethylene / hexafluoropropylene copolymer is preferred, at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymer and tetrafluoroethylene / hexafluoropropylene / fluoroalkyl vinyl ether copolymer is more preferred, and tetrafluoroethylene / fluoroalkyl vinyl ether copolymer is even more preferred. By selecting a fluororesin containing fluoroalkyl vinyl ether units, the MFR change rate can be more easily adjusted within the above-mentioned range.

[0063] As the fluoroalkyl vinyl ether, at least one selected from the group consisting of perfluoro(methyl vinyl ether) (CF2=CF-O-CF3), perfluoro(ethyl vinyl ether) (CF2=CF-O-C2F5), and perfluoro(propyl vinyl ether) (CF2=CF-O-C3F7) is preferred, and at least one selected from the group consisting of perfluoro(ethyl vinyl ether) and perfluoro(propyl vinyl ether) is more preferred.

[0064] The content of fluoroalkyl vinyl ether units in the tetrafluoroethylene / fluoroalkyl vinyl ether copolymer is preferably 1.0 to 12.0% by mass, more preferably 1.5% by mass or more, even more preferably 2.0% by mass or more, even more preferably 2.5% by mass or more, more preferably 10.0% by mass or less, and even more preferably 8.0% by mass or less, relative to the total monomer units of the copolymer.

[0065] The content of tetrafluoroethylene units in the tetrafluoroethylene / fluoroalkyl vinyl ether copolymer is preferably 88.0 to 99.0% by mass, more preferably 90.0% by mass or more, even more preferably 92.0% by mass or more, preferably 98.5% by mass or less, more preferably 98.0% by mass or less, and even more preferably 97.5% by mass or less, relative to the total monomer units of the copolymer.

[0066] In one embodiment, the tetrafluoroethylene / fluoroalkyl vinyl ether copolymer does not contain hexafluoropropylene units, or contains less than 0.1% by mass of hexafluoropropylene units relative to the total monomer units of the copolymer. In another embodiment, the tetrafluoroethylene / fluoroalkyl vinyl ether copolymer contains only tetrafluoroethylene units and fluoroalkyl vinyl ether units.

[0067] The content of hexafluoropropylene units in the tetrafluoroethylene / hexafluoropropylene copolymer is preferably 0.1 to 25.0% by mass, more preferably 1.0% by mass or more, even more preferably 2.0% by mass or more, even more preferably 20.0% by mass or less, and even more preferably 15.0% by mass or less, relative to the total monomer units of the copolymer.

[0068] The content of tetrafluoroethylene units in the tetrafluoroethylene / hexafluoropropylene copolymer is preferably 70.0 to 99.8% by mass, more preferably 75.0% by mass or more, even more preferably 80.0% by mass or more, even more preferably 98.0% by mass or less, and even more preferably 97.0% by mass or less, relative to the total monomer units of the copolymer.

[0069] The tetrafluoroethylene / hexafluoropropylene copolymer may contain fluoroalkyl vinyl ether units. That is, the fluororesin may be a tetrafluoroethylene / hexafluoropropylene / fluoroalkyl vinyl ether copolymer. The content of fluoroalkyl vinyl ether units in the copolymer is preferably 0.1 to 20.0% by mass, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, even more preferably 10.0% by mass or less, and even more preferably 3.0% by mass or less, relative to the total monomer units of the copolymer.

[0070] The copolymer may contain units based on monomers other than tetrafluoroethylene units, fluoroalkyl vinyl ether units, and hexafluoropropylene units. Other monomers include vinyl fluoride, vinylidene fluoride, chlorotrifluoroethylene, and CZ. 1 Z 2 =CZ 3 (CF2) n Z 4 (In the formula, Z 1 , Z 2 and Z 3 These represent H or F, and Z, which are the same or different. 4 ∫ represents H, F, or Cl, and n is an integer from 2 to 10. The vinyl monomer represented by CF₂ = CF-OCH₂-Rf 3 (In the formula, Rf 3 represents a perfluoroalkyl group having 1 to 5 carbon atoms. Examples include alkyl perfluorovinyl ether derivatives represented by ), ethylene, and propylene. The content of other monomers is preferably 0 to 0.5% by mass, more preferably 0.05 to 0.3% by mass, and even more preferably 0.1 to 0.2% by mass, relative to the total monomer units of the copolymer.

[0071] The fluororesin contained in the molding material of this disclosure can be produced by bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc. However, suspension polymerization is preferred because it does not necessarily require the use of surfactants, coagulants, etc. as materials used in polymerization, and the metal content can be easily controlled.

[0072] In this disclosure, the content of each monomer unit in the fluororesin is: 19 Measurement is performed using the 1F-NMR method.

[0073] The melting point of the fluororesin is preferably 200°C or higher, more preferably 210°C or higher, even more preferably 220°C or higher, preferably 320°C or lower, and more preferably 315°C or lower.

[0074] The melting point of the tetrafluoroethylene / fluoroalkyl vinyl ether copolymer is preferably 280°C or higher, more preferably 285°C or higher, even more preferably 290°C or higher, preferably 320°C or lower, and more preferably 315°C or lower.

[0075] The melting point of the tetrafluoroethylene / hexafluoropropylene copolymer is preferably 200°C or higher, more preferably 210°C or higher, even more preferably 220°C or higher, preferably 300°C or lower, more preferably 285°C or lower, and even more preferably 270°C or lower.

[0076] In this disclosure, the melting point can be measured using a differential scanning calorimetry (DSC).

[0077] In one embodiment, the fluororesin molded article (I) contains components other than fluororesin (hereinafter sometimes referred to as "other components"). In one embodiment, the fluororesin molded article (I) substantially does not contain other components. In one embodiment, the fluororesin molded article (I) contains no other components at all, or contains only trace amounts of other components (for example, less than 0.1% by mass or less than 0.01% by mass) relative to the mass of the molded article.

[0078] Other components include fillers, plasticizers, processing aids, mold release agents, pigments, flame retardants, lubricants, light stabilizers, weather stabilizers, conductive agents, antistatic agents, ultraviolet absorbers, antioxidants, foaming agents, fragrances, oils, softeners, and hydrofluoricating agents.

[0079] In the manufacturing method of the present disclosure, the fluororesin molded article (I) may be crushed to produce pulverized products having a maximum length of less than 15 mm that can be conveyed in a melt shearing apparatus, and the pulverized products may be subjected to melt shearing. The size of the fluororesin molded article (I) is not particularly specified as long as it can be conveyed in a melt shearing apparatus, but for application to a general melt shearing apparatus, it is preferable that the maximum length of the fluororesin molded article (I) is 15 mm or less. In particular, if the fluororesin molded article (I) includes molded articles having a maximum length of 15 mm or more, it is preferable to produce pulverized products having a maximum length of less than 15 mm and then perform melt shearing on the pulverized products. This makes it easier to perform melt shearing using a screw-type extrusion molding machine or screw-type injection molding machine equipped with a screw with a screw groove depth of less than 15 mm. The screw groove depth is the distance between the grooves provided at the difference between the maximum and minimum diameters of the screw.

[0080] Crushing refers to the process of dividing raw materials using energy to reduce their size (volume). Examples of energy include compression, impact, collision, shear, and abrasion. Examples of crushing by compression include jaw crushers, gyrant rerry crushers, cone crushers, and roll crushers. Examples of crushing by impact include hammer mills, pin mills, and mill grinders. Examples of crushing by collision include jet mills and ball mills. Examples of crushing by shear include single-screw pusher crushers, granulators, plastic runner crushers, cutter mills, shredders, and guillotine cutters. Examples of crushing by abrasion include disc mills and millstones. Some of these processes involve not just one type of energy but a combination of multiple energies. Because fluororesins are soft and tend to stretch thin when rubbed under stress, shear-type crushing is preferable as it minimizes friction. Among shear-type crushing machines, single-screw pusher crushers, granulators, and plastic runner crushers are preferred because they minimize friction while applying stress.

[0081] The crushing process may be performed once or repeatedly until a molded body of the desired shape can be produced. By using a mesh screen, the material can be easily crushed to a size smaller than the mesh size. The crushed molded body may also be classified by known methods such as airflow classification.

[0082] The shape of the crushed molded body is not particularly limited and may be particulate, granular, or other shapes. The maximum length of a single piece of the crushed molded body is not particularly limited as long as it can be supplied to the molding machine, but may be, for example, 0.1 mm or more, 1 mm or more, 3 mm or more, less than 15 mm, 10 mm or less, or 8 mm or less.

[0083] By using the manufacturing method of the present disclosure, pellets can be produced as a fluororesin molding material (II). Since pellets usually have a uniform size, by using pellets obtained by the manufacturing method of the present disclosure, it is possible to smoothly manufacture molded articles having a desired shape without impairing the excellent properties inherent in the fluororesin, while suppressing the occurrence of molding defects.

[0084] For the melt shearing process used in manufacturing pellets, a screw-type extruder, preferably one equipped with a screw with a groove depth of less than 15 mm, can be used. In one embodiment, a fluororesin molded body (I) or a pulverized product obtained from a fluororesin molded body (I) is melted, extruded, and cut to a predetermined length using an extruder to produce pellets.

[0085] The shape of the pellets is not particularly limited and may be any shape that fluororesin pellets typically have. For example, the pellets may be disc-shaped or cylindrical with a diameter of 0.3 to 10.0 mm, preferably 0.5 to 7.0 mm, more preferably 1.0 to 5.0 mm, and a height (thickness) of 0.3 to 10.0 mm, preferably 0.5 to 7.0 mm, more preferably 1.0 to 5.0 mm. If the pellets are smaller than the above range, handling becomes difficult, and static electricity is easily generated, leading to contamination by foreign matter and adhesion to the surface of the equipment. If the pellets are larger, they may not be able to be stably fed into the screw, and the melting state in the cylinder may become uneven, making discharge from the nozzle or extrusion die at the tip of the cylinder unstable and causing molding defects.

[0086] The obtained fluororesin molding material (II), such as pellets, can be molded by known methods to form a molded body having a desired shape. In one embodiment, after producing pellets as the fluororesin molding material (II) using the manufacturing method of the present disclosure, the pellets are subjected to melt shear treatment using a screw-type extrusion molding machine or screw-type injection molding machine equipped with screws with a groove depth of less than 15 mm to produce a molded body (excluding the pellets).

[0087] By using the manufacturing method disclosed herein, a fluororesin molding material (II) having the characteristics of the molding material described later can be manufactured.

[0088] 2.Molding material This disclosure also relates to a molding material in which the -CH2OH index (X), calculated by the following formula from the height of each peak appearing in a chart obtained by Fourier transform infrared spectroscopy, is 0.90 or less, preferably 0.85. -CH2OH index (X)=C / (C+D) C: 3648cm -1 Height of the peak originating from -CH2OH appearing nearby D: 1856cm -1 The height of the peaks appearing in the vicinity (peaks originating from main chain elongation)

[0089] In the manufacturing method of the present disclosure, by using a fluororesin molded article (I) formed from a fluororesin having -CH2OH as a raw material, a molded material having the -CH2OH index (X) within the above range can be obtained.

[0090] In one embodiment, the molding material can be characterized by the fact that the height of each peak appearing in the chart obtained by measurement using Fourier transform infrared spectroscopy, and the melt flow rate (MFR), are calculated by the following formula, and the -CH2OH index (Y) is 0.45 or less, preferably 0.40 or less. -CH2OH index (Y)=C / (C+D)×A -0.2 A: MFR (g / 10 min) of molding material at 372°C C: 3648cm -1 Height of the peak originating from -CH2OH appearing nearby D: 1856cm -1 The height of the peaks appearing in the vicinity (peaks originating from main chain elongation)

[0091] In the manufacturing method of the present disclosure, a molded fluororesin article (I) formed from a fluororesin having -CH2OH is appropriately adjusted and is used as a raw material, thereby obtaining a molded material having a -CH2OH index (Y) within the above range.

[0092] In one embodiment, the fluororesin forming the molding material has -CH2OH. The number of -CH2OH groups in the fluororesin forming the molding material is such that the main chain has 10 carbon atoms. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, and especially preferably 30 or more. There is no particular upper limit, but it may be 500 or less.

[0093] In one embodiment, the fluororesin forming the molding material has -COF and -COOH. The total number of -COF and -COOH in the fluororesin forming the molding material is 10 carbon atoms in the main chain. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably more than 6, even more preferably 10 or more, particularly preferably 20 or more, most preferably 30 or more, with an upper limit of preferably 500 or less, and more preferably 300 or less.

[0094] In one embodiment, the fluororesin forming the molding material has at least one functional group selected from the group consisting of -CH2OH, -COF, and -COOH. The total number of -CH2OH, -COF, and -COOH groups in the fluororesin forming the molding material is 10 carbon atoms in the main chain. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, and especially preferably 30 or more. There is no particular upper limit, but it may be 500 or less.

[0095] In one embodiment, the fluororesin forming the molding material has -CF2H. The number of -CF2H atoms in the fluororesin forming the molding material is such that the main chain has 10 carbon atoms. 6 Preferably, there are 1 or more per unit, more preferably 6 or more, even more preferably 10 or more, even more preferably 20 or more, particularly preferably 30 or more, preferably 500 or less, more preferably 400 or less, and even more preferably 300 or less.

[0096] In one embodiment, the fluororesin forming the molding material has functional groups. The number of functional groups in the fluororesin forming the molding material is such that the main chain has 10 carbon atoms. 6The number of functional groups per unit is preferably 1 or more, more preferably 6 or more, even more preferably 10 or more, still more preferably 20 or more, and particularly preferably 30 or more. There is no particular upper limit, but it may be 700 or less. The number of functional groups may be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0097] As the fluororesin used to form the molding material, at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymers and tetrafluoroethylene / hexafluoropropylene copolymers is preferred, at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymers and tetrafluoroethylene / hexafluoropropylene / fluoroalkyl vinyl ether copolymers is more preferred, and tetrafluoroethylene / fluoroalkyl vinyl ether copolymers are even more preferred. Examples of these copolymers include those described above as fluororesins used to form the fluororesin molded article (I).

[0098] In one embodiment, the molding material has a tensile strength (TS) of 15 MPa or more. The tensile strength is preferably 20 MPa or more, more preferably 25 MPa or more, and there is no particular upper limit, but it may be 50 MPa or less.

[0099] The tensile strength can be measured by the method described in the examples.

[0100] In one embodiment, the molding material has a tensile elongation (EL) of 250% or more. The tensile elongation is preferably 300% or more, more preferably 330% or more, and even more preferably 350% or more, and there is no particular upper limit, but it may be 600% or less.

[0101] Tensile elongation can be measured by the method described in the examples.

[0102] The molding material of this disclosure can be used for known applications of fluororesins. In one embodiment, the molding material of this disclosure is a pellet. The pellet of this disclosure can be manufactured, for example, by manufacturing a pellet as a fluororesin molding material (II) using the manufacturing method of this disclosure.

[0103] This disclosure also relates to molded articles (excluding pellets) obtained from molding materials. The molded articles (excluding pellets) of this disclosure can be manufactured, for example, by producing pellets as a fluororesin molding material (II) using the manufacturing method of this disclosure, and then performing a melt shear treatment using the pellets as raw material. That is, the molded articles (excluding pellets) of this disclosure can be suitably manufactured by the manufacturing method of the molded articles of this disclosure. Alternatively, molded articles (excluding pellets) can be manufactured by mixing the pellets of this disclosure with pellets of a virgin polymer and then performing a melt shear treatment.

[0104] A molded product can be obtained by molding the molding material of this disclosure. The method for molding the above-mentioned molding material is not particularly limited, but can include melt molding, and known methods such as extrusion molding, injection molding, transfer molding, inflation molding, and compression molding can be used. These molding methods can be appropriately selected depending on the shape of the molded product to be obtained.

[0105] The molding method for the above-mentioned molding material is preferably extrusion molding, compression molding, or injection molding, with extrusion molding being more preferable. Using these molding methods, molded products such as tubes, films, and bottles can be easily manufactured.

[0106] The shape of the molded product described above is not particularly limited and includes, for example, films, sheets, plates, rods, blocks, cylinders, containers, electric wires, tubes, fittings, sealing materials, bottles, wafer carriers, etc. It may also be a fluororesin coating that forms a coating layer for cooking utensils such as the inner pot of a rice cooker, a hot plate, or a frying pan, or a topcoat layer for a fixing roller in an image forming device such as an electrophotographic or electrostatic recording copier or a laser printer. The fluororesin coating can be formed by applying a fluororesin paint to a substrate.

[0107] The above molded products are not particularly limited, but can be applied to the following uses, for example: Diaphragm pump diaphragms, bellows molded products, wire insulation, semiconductor components, packings and seals, thin-walled tubes for copy rolls, monofilaments, belts, gaskets, optical lens components, tubes for oil drilling, tubes for geothermal power generation, power lines for oil drilling, power lines for satellites, power lines for nuclear power generation, power lines for aircraft, solar panel films, gaskets for secondary batteries and electric double-layer capacitors, OA rolls, etc.

[0108] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

[0109] <1> According to the first aspect of this disclosure, A method for producing a fluororesin molding material (II) by performing a melt shear treatment on a fluororesin molded article (I) formed from a fluororesin that has undergone two or more melt shear treatments performed above the melting point of the fluororesin, the method comprising: The melt flow rate (MFR) change rate is within the range of -15% to +15%. A manufacturing method is provided. MFR change rate (%) = log 10 (A / B) × 100 A: MFR (g / 10 min) of fluoropolymer molding material (II) at 372°C B: MFR (g / 10 min) of fluoropolymer molded article (I) at 372°C <2> According to the second aspect of this disclosure, A first method for manufacturing a fluororesin molded article (I) is provided, which includes a molded article having a shape that is difficult to treat by melt shearing using a screw-type molding machine. <3> According to the third aspect of this disclosure, A method for manufacturing a fluororesin molded article (I) is provided, according to a first or second aspect, including a molded article having a maximum length of 15 mm or more. <4> According to the fourth aspect of this disclosure, A method is provided for manufacturing a fluoropolymer molded article (I) including a sprue or runner, according to any of the first to third aspects. <5> According to the fifth aspect of this disclosure, A manufacturing method is provided for a fluororesin molded article (I) in which the MFR at 372°C is 100.0 g / 10 min or less, according to any of the first to fourth aspects. <6> According to the sixth aspect of this disclosure, The fluororesin forming the fluororesin molded article (I) has functional groups, and the number of these functional groups is such that the main chain has 10 carbon atoms. 6 A manufacturing method is provided that involves one or more of the first to fifth aspects per unit. <7> According to the seventh aspect of this disclosure, The fluororesin forming the fluororesin molded article (I) has at least one functional group selected from the group consisting of -CH2OH, -COF, and -COOH, and the number of said functional groups is such that the main chain has 10 carbon atoms. 6 A manufacturing method is provided that involves one or more units per unit, according to any of the first to sixth perspectives. <8> According to the eighth aspect of this disclosure, The fluororesin forming the fluororesin molded article (I) has -CH2OH, and the number of -CH2OH is such that the main chain has 10 carbon atoms. 6 A manufacturing method is provided that involves one or more units per unit, according to any of the first to seventh aspects. <9> According to the ninth aspect of this disclosure, A manufacturing method is provided according to any of the first to eight points, wherein the temperature of the molten shear treatment is 390°C or lower. <10> According to the tenth aspect of this disclosure, The fluororesin forming the fluororesin molded article (I) has functional groups, and the number of these functional groups is such that the main chain has 10 carbon atoms. 6 A manufacturing method is provided in which there is one or more units per piece, and the melt shear treatment temperature is 360 to 390°C, according to any of the first to ninth aspects. <11> According to the eleventh aspect of this disclosure, A method for producing a fluororesin molded article (I) is provided, wherein the fluororesin used to form the fluororesin molded article (I) is at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymers and tetrafluoroethylene / hexafluoropropylene copolymers, according to any of the first to tenth aspects. <12> According to the 12th aspect of this disclosure, A method for producing a fluororesin molded article (I) is provided, in which the fluororesin is a tetrafluoroethylene / fluoroalkyl vinyl ether copolymer, according to any of the first to eleventh aspects. <13> According to the 13th aspect of this disclosure, A manufacturing method is provided, comprising crushing a fluororesin molded body (I) to produce a pulverized product having a maximum length of less than 15 mm, and then performing a melt shear treatment on the pulverized product, according to any of the first to twelfth aspects. <14> According to the fourteenth aspect of this disclosure, A manufacturing method is provided, comprising crushing a fluororesin molded article (I) including a molded article having a maximum length of 15 mm or more to produce a pulverized product having a maximum length of less than 15 mm, and then performing a melt shear treatment on the pulverized product using a screw-type extrusion molding machine or screw-type injection molding machine equipped with a screw with a groove depth of less than 15 mm, according to any of the first to thirteenth viewpoints. <15> According to the 15th aspect of this disclosure, A method for manufacturing a fluororesin molding material (II) in any of the first to fourteen aspects is provided, wherein the fluororesin molding material (II) is a pellet. <16> According to the sixteenth aspect of this disclosure, A manufacturing method is provided in which the -CH2OH index (X), calculated by the following formula from the height of each peak appearing in the chart of the fluoropolymer molding material (II) measured by Fourier transform infrared spectroscopy, is 0.90 or less, according to any of the first to fifteen viewpoints. -CH2OH index (X)=C / (C+D) C: 3648cm -1 Height of the peak originating from -CH2OH appearing nearby D: 1856cm -1 Height of the peaks appearing nearby <17> According to the seventeenth aspect of this disclosure, A manufacturing method is provided that meets any of the first to sixteen criteria, wherein the height of each peak appearing in the chart of the fluoropolymer molding material (II) measured by Fourier transform infrared spectroscopy, and the -CH2OH index (Y) calculated from the MFR of the fluoropolymer molding material (II) using the following formula, are 0.45 or less. -CH2OH index (Y)=C / (C+D)×A -0.2 A: MFR (g / 10 min) of fluoropolymer molding material (II) at 372°C C: 3648cm -1 Height of the peak originating from -CH2OH appearing nearby D: 1856cm -1 Height of the peaks appearing nearby <18> According to the 18th aspect of this disclosure, The total number of -COF and -COOH groups in the fluororesin forming the fluororesin molding material (II) is 10 carbon atoms. 6 A manufacturing method is provided that produces 300 or fewer units per unit, according to any of the first to seventeen perspectives. <19> According to the 19th aspect of this disclosure, A method for manufacturing a molded article is provided, which involves first manufacturing pellets as a fluororesin molding material (II) using a manufacturing method according to any of the 1 to 18 aspects, and then using the pellets as raw material, performing a melt shear treatment using a screw-type extrusion molding machine or screw-type injection molding machine equipped with a screw with a groove depth of less than 15 mm to produce a molded article (excluding the pellets). <20> According to the 20th aspect of this disclosure, A molding material formed from a fluororesin is provided, wherein the -CH2OH index (X), calculated by the following formula from the heights of each peak appearing in a chart obtained by Fourier transform infrared spectroscopy, is 0.90 or less. -CH2OH index (X)=C / (C+D) C: 3648cm -1 Height of the peak originating from -CH2OH appearing nearby D: 1856cm -1 Height of the peaks appearing nearby <21> According to the 21st aspect of this disclosure, A molding material is provided that meets a 20th criterion, wherein the height of each peak appearing in the chart obtained by measurement using Fourier transform infrared spectroscopy, and the melt flow rate (MFR), are used to calculate the -CH2OH index (Y) by the following formula, which is 0.45 or less. -CH2OH index (Y)=C / (C+D)×A -0.2 A: MFR (g / 10 min) of molding material at 372°C C: 3648cm -1 Height of the peak originating from -CH2OH appearing nearby D: 1856cm -1 Height of the peaks appearing nearby <22> According to the 22nd aspect of this disclosure, The total number of -COF and -COOH groups is equal to the number of carbon atoms in a 10-carbon group. 6 A molding material according to a 20th or 21st viewpoint is provided, which is formed from a fluororesin having 300 or fewer particles per unit. <23> According to the 23rd aspect of this disclosure, The total number of -COF and -COOH groups is equal to the number of carbon atoms in a 10-carbon group. 6 A molding material is provided that is formed from a fluororesin, with each unit having more than 6 and no more than 300 units, according to any of the 20th to 22nd viewpoints. <24> According to the 24th aspect of this disclosure, A molding material is provided that is formed from a fluororesin, wherein the fluororesin is at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymers and tetrafluoroethylene / hexafluoropropylene copolymers, according to any 20th to 23rd viewpoint. <25> According to Perspective 25 of this Disclosure, A molding material is provided which is formed from a fluororesin, wherein the fluororesin is a tetrafluoroethylene / fluoroalkyl vinyl ether copolymer, according to any 20th to 24th viewpoint. <26> According to Perspective 26 of this Disclosure, A molding material is provided that has a tensile strength of 20 MPa or more, according to any of the 20th to 25th views. <27> According to Perspective 27 of this Disclosure, A molding material is provided that has a tensile elongation of 250% or more, according to any of the 20th to 26th views. <28> According to Perspective 28 of this Disclosure, A molding material is provided that is manufactured using a fluororesin molded article formed from a fluororesin that has undergone two or more melt shear treatments performed at a temperature above the melting point of the fluororesin as a raw material, in accordance with any of the 20th to 27th views. <29> According to Perspective 29 of this Disclosure, A molding material is provided that is a pellet, according to any of the 20th to 28th views. <30> According to the 30th aspect of this disclosure, A molded article (excluding pellets) obtained from a molding material according to any of the 20th to 29th aspects is provided. [Examples]

[0110] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to such embodiments.

[0111] Each value in the experimental example was measured using the following method.

[0112] <Composition of fluoropolymer> The content of each monomer unit was measured using an NMR analyzer (for example, a Bruker BioSpin AVANCE300 high-temperature probe).

[0113] <Meltflow Rate> In accordance with ASTM D1238, the mass (g / 10 min) of polymer flowing out of a nozzle with an inner diameter of 2.1 mm and a length of 8 mm per 10 minutes was determined using a melt indexer G-01 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 372°C under a 5 kg load.

[0114] <Melting point> Using a differential scanning calorimeter (product name: X-DSC7000, manufactured by Hitachi High-Tech Science Corporation), the temperature was increased from 200°C to 350°C at a heating rate of 10°C / min, followed by cooling from 350°C to 200°C at a cooling rate of 10°C / min. A second heating was then performed from 200°C to 350°C at a heating rate of 10°C / min, and the melting point was determined from the melting curve peak generated during the second heating process.

[0115] <Functional group, peak height> Copolymers were molded by cold pressing to produce films with a thickness of 0.25 to 0.30 mm. These films were scanned 40 times using a Fourier transform infrared spectrometer (FT-IR, Spectrum One, PerkinElmer) to obtain infrared absorption spectra, and the difference spectrum from the base spectrum, which is completely fluorinated and lacks functional groups, was obtained. From the absorption peaks of specific functional groups appearing in this difference spectrum, the carbon atoms in the sample (1 × 10⁶) were analyzed according to the following formula (A). 6 The number of functional units N per individual was calculated. N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm) The correction factor for -CH2OH was set to 2236, the correction factor for -COF to 388, and the correction factor for -COOH to 439. -The peak height and 1856cm originate from CH2OH. -1The height of the peak appearing in the vicinity was determined from the obtained infrared absorption spectrum.

[0116] <- Number of CF2H > The number of -CF2H groups in a fluorine-containing copolymer was determined using a nuclear magnetic resonance spectrometer AVANCE-300 (Bruker BioSpin) at a measurement temperature of (polymer melting point + 20°C). 19 The peak integral value of the -CF2H group was determined by performing 1F-NMR measurements.

[0117] <Tensile strength (TS), Tensile elongation (EL)> Using the pellets and heat press molding machine prepared in Experimental Examples 3 and 8, 2.0 mm thick test specimens (compression molded) were obtained. From these specimens, dumbbell-shaped test pieces were cut out using an ASTM V-type dumbbell. Using the obtained dumbbell-shaped test pieces, the tensile strength and tensile elongation were measured at 25°C under conditions of 50 mm / min using an Autograph (Shimadzu Corporation AG-I 300kN) in accordance with ASTM D638.

[0118] The following molded bodies were used in the experimental examples. The physical properties of each molded body are shown in Table 2.

[0119] Molded body 1 Injection molded parts (sprue, runner) Tetrafluoroethylene / perfluoropropyl vinyl ether copolymer Maximum length: 30-200mm

[0120] Molded body 2 Injection molded parts (sprue, runner) Tetrafluoroethylene / perfluoropropyl vinyl ether copolymer Maximum length: 30-200mm

[0121] Molded body 3 Injection molded parts (sprue, runner) Tetrafluoroethylene / perfluoropropyl vinyl ether copolymer Maximum length: 30-200mm

[0122] Molded body 4 Injection molded parts (sprue, runner) Tetrafluoroethylene / perfluoropropyl vinyl ether copolymer Maximum length: 30-200mm

[0123] Molded body 5 Extruded body (tube) Tetrafluoroethylene / perfluoropropyl vinyl ether copolymer Maximum length: 30-500mm

[0124] [Table 2]

[0125] Experimental Example 1 Molded body 1 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd., with a screw groove depth of 8 mm) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0126] Experimental Example 2 The pellets obtained in Experimental Example 1 were injection molded using a screw-type injection molding machine (SE50EV-A manufactured by Sumitomo Heavy Industries, Ltd.) with a cylinder temperature of 390°C, a mold temperature of 200°C, and an injection speed of 30 mm / s (residence time in the injection molding machine of approximately 2 minutes). Products with the desired shape were recovered as injection molded bodies, and sprues and runners with a maximum length of 30 to 200 mm were recovered as scrap materials.

[0127] Experimental Example 3 The injection-molded bodies (sprue and runner) obtained in Experimental Example 2 were crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0128] Experimental Example 4 Molded bodies 1 and 2 were each crushed using a granulator (HARMO GRANCUTTER SPCII-C200) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The crushed material from molded body 1 and the crushed material from molded body 2 were mixed in a ratio of 1:4 (by mass) and extruded using a screw-type extruder (Imoto Seisakusho IMC-9513) at a molding temperature of 370°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0129] Experimental Example 5 Molded body 1 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 390°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0130] Experimental Example 6 Molded body 1 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 360°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0131] Experimental Example 7 The molded body 3 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0132] Experimental Example 8 The molded body 4 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0133] Experimental Example 9 The molded body 5 was crushed using a cutting mill (Retsch cutting mill SM300) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material was extruded using a screw-type extruder (Imoto Seisakusho Co., Ltd. IMC-9513) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0134] The results are shown in Table 3. [Table 3]

[0135] Experimental Example 10 Molded body 1 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material of molded body 1 and PFA pellets 1 (MFR: 31.2 g / 10 min, PPVE: 5.5 mass%) were mixed in a 4:1 ratio (mass ratio) and extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0136] Experimental Example 11 Molded body 1 was crushed using a granulator (GRANCUTTER SPCII-C200, manufactured by HARMO Corporation) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material of molded body 1 and PFA pellets 1 (MFR: 31.2 g / 10 min, PPVE: 5.5 mass%) were mixed in a 1:1 ratio (mass ratio) and extruded using a screw-type extruder (IMC-9513, manufactured by Imoto Seisakusho Co., Ltd.) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0137] Experimental Example 12 Molded body 1 was crushed using a granulator (HARMO GRANCUTTER SPCII-C200) to obtain crushed material with a maximum length of 3 to 8 mm (uneven size). The obtained crushed material of molded body 1 and PFA pellets 1 (MFR: 31.2 g / 10 min, PPVE: 5.5 mass%) were mixed in a ratio of 35:65 (mass ratio), and the mixture was extruded using a screw-type extruder (Imoto Seisakusho IMC-9513) at a molding temperature of 380°C (20 rpm, residence time in the extruder approximately 4 minutes) to obtain uniformly shaped pellets without coloration.

[0138] The results are shown in Table 4.

[0139] [Table 4]

Claims

1. A method for producing a fluororesin molding material (II) by performing a melt shear treatment on a fluororesin molded article (I) formed from a fluororesin that has undergone two or more melt shear treatments performed above the melting point of the fluororesin, the method comprising: The melt flow rate (MFR) change rate is within the range of -15% to +15%. Manufacturing method. MFR change rate (%) = log １０ (A / B) × 100 A: MFR (g / 10 min) of fluoropolymer molding material (II) at 372°C B: MFR (g / 10 min) of fluororesin molded article (I) at 372°C

2. The manufacturing method according to claim 1, wherein the fluororesin molded article (I) includes a molded article having a shape that is difficult to perform melt shear treatment using a screw-type molding machine.

3. The manufacturing method according to claim 1 or 2, wherein the fluororesin molded article (I) includes a molded article having a maximum length of 15 mm or more.

4. The manufacturing method according to claim 1 or 2, wherein the fluororesin molded article (I) includes a sprue or runner.

5. The manufacturing method according to claim 1 or 2, wherein the MFR of the fluororesin molded article (I) at 372°C is 100.0 g / 10 min or less.

6. The fluororesin forming the fluororesin molded article (I) has functional groups, and the number of these functional groups is such that the main chain has 10 carbon atoms. ６ The manufacturing method according to claim 1 or 2, wherein each unit contains one or more units.

7. The fluororesin forming the fluororesin molded article (I) is -CH ２ It has at least one functional group selected from the group consisting of OH, -COF, and -COOH, and the number of said functional groups is such that the main chain has 10 carbon atoms. ６ The manufacturing method according to claim 1 or 2, wherein each unit contains one or more units.

8. The fluororesin forming the fluororesin molded article (I) is -CH ２ It has OH and -CH ２ The number of OH groups is equal to the number of carbon atoms in the main chain (10). ６ The manufacturing method according to claim 1 or 2, wherein each unit contains one or more units.

9. The manufacturing method according to claim 1 or 2, wherein the temperature of the molten shear treatment is 390°C or lower.

10. The fluororesin forming the fluororesin molded article (I) has functional groups, and the number of these functional groups is such that the main chain has 10 carbon atoms. ６ The manufacturing method according to claim 1 or 2, wherein there is one or more per unit, and the melt shear treatment temperature is 360 to 390°C.

11. The manufacturing method according to claim 1 or 2, wherein the fluororesin used to form the fluororesin molded article (I) is at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymers and tetrafluoroethylene / hexafluoropropylene copolymers.

12. The manufacturing method according to claim 1 or 2, wherein the fluororesin used to form the fluororesin molded article (I) is a tetrafluoroethylene / fluoroalkyl vinyl ether copolymer.

13. A manufacturing method according to claim 1 or 2, comprising crushing a fluororesin molded body (I) to produce a pulverized product having a maximum length of less than 15 mm, and performing a melt shear treatment on the pulverized product.

14. The manufacturing method according to claim 1 or 2, comprising: crushing a fluororesin molded article (I) including a molded article having a maximum length of 15 mm or more to produce a pulverized product having a maximum length of less than 15 mm; and performing a melt shear treatment on the pulverized product using a screw-type extrusion molding machine or screw-type injection molding machine equipped with a screw with a groove depth of less than 15 mm.

15. The manufacturing method according to claim 1 or 2, wherein the fluororesin molding material (II) is pellets.

16. From the height of each peak appearing in the chart of the fluororesin molding material (II) measured by Fourier transform infrared spectroscopy, the -CH ２ OH index (X) calculated by the following formula is 0.90 or less, and the manufacturing method according to claim 1 or 2. -CH ２ OH index (X) = C / (C + D) C: 3648cm －１ Appears nearby - CH ２ Peak height originating from OH D: 1856cm －１ Height of the peaks appearing nearby

17. -CH is calculated from the height of each peak appearing in the chart of the fluoropolymer molding material (II) measured by Fourier transform infrared spectroscopy, and from the MFR of the fluoropolymer molding material (II), using the following formula. ２ The manufacturing method according to claim 1 or 2, wherein the OH index (Y) is 0.45 or less. -CH ２ OH index (Y) = C / (C + D) × A －０．２ A: MFR (g / 10 min) of fluoropolymer molding material (II) at 372°C C: 3648cm －１ Appears nearby - CH ２ Peak height originating from OH D: 1856cm －１ Height of the peaks appearing nearby

18. The total number of -COF and -COOH groups in the fluororesin forming the fluororesin molding material (II) is 10 carbon atoms. ６ The manufacturing method according to claim 1 or 2, wherein the quantity per unit is 300 or less.

19. A method for manufacturing a molded article, comprising: manufacturing pellets as a fluororesin molding material (II) using the manufacturing method described in claim 1 or 2; and then using the pellets as raw material and performing a melt shearing treatment using a screw-type extrusion molding machine or screw-type injection molding machine equipped with a screw with a groove depth of less than 15 mm to manufacture a molded article (excluding the pellets).

20. A molding material formed from fluororesin, the following formula is used to calculate the -CH ratio from the height of each peak appearing in the chart obtained by Fourier transform infrared spectroscopy: ２ A molding material having an OH index (X) of 0.90 or less. -CH ２ OH index (X) = C / (C + D) C: 3648cm －１ Appears nearby - CH ２ Peak height originating from OH D: 1856cm －１ Height of the peaks appearing nearby

21. The height of each peak appearing in the chart obtained by Fourier transform infrared spectroscopy, and the melt flow rate (MFR), are used to calculate -CH using the following formula. ２ The molding material according to claim 20, wherein the OH index (Y) is 0.45 or less. -CH ２ OH index (Y) = C / (C + D) × A －０．２ A: MFR (g / 10 min) of the molding material at 372°C C: 3648cm －１ Appears nearby - CH ２ Peak height originating from OH D: 1856cm －１ Height of the peaks appearing nearby

22. The total number of -COF and -COOH groups is equal to the number of carbon atoms (10). ６ A molding material according to claim 20 or 21, formed from a fluororesin having 300 or fewer particles per unit.

23. The total number of -COF and -COOH groups is equal to the number of carbon atoms (10). ６ The molding material according to claim 20 or 21, which is formed from a fluororesin having a number of particles greater than 6 and 300 or less per particle.

24. The molding material according to claim 20 or 21, wherein the fluororesin is formed from a fluororesin, and the fluororesin is at least one selected from the group consisting of tetrafluoroethylene / fluoroalkyl vinyl ether copolymer and tetrafluoroethylene / hexafluoropropylene copolymer.

25. A molding material according to claim 20 or 21, wherein the fluororesin is formed from a fluororesin, and the fluororesin is a tetrafluoroethylene / fluoroalkyl vinyl ether copolymer.

26. The molding material according to claim 20 or 21, wherein the tensile strength is 20 MPa or more.

27. The molding material according to claim 20 or 21, wherein the tensile elongation is 250% or more.

28. The molding material according to claim 20 or 21, which is a molding material manufactured using a fluororesin molded article formed from a fluororesin that has undergone two or more melt shear treatments performed at a melting point above the melting point of the fluororesin as a raw material.

29. The molding material according to claim 20 or 21, which is a pellet.

30. A molded article obtained from the molding material according to claim 20 or 21 (excluding pellets).

Images