Method for manufacturing a fluororesin molded article, and fluororesin molded article

Abstract

The present invention provides a method for manufacturing a fluororesin molded article that can produce a fluororesin molded article with good tensile properties, and a fluororesin molded article. [Solution] A method for manufacturing a fluororesin molded article, comprising the step of obtaining a fluororesin molded article by molding a molding material containing fluororesin with an electromagnetic wave irradiation molding apparatus.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a fluororesin molded body and a fluororesin molded body.

Background Art

[0002] As a processing method for a fluororesin having a high melt viscosity such as polytetrafluoroethylene, a method of cutting after compression molding is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a method for manufacturing a fluororesin molded body capable of obtaining a fluororesin molded body having good tensile properties and a fluororesin molded body.

Means for Solving the Problems

[0005] The present disclosure (1) is a method for manufacturing a fluororesin molded body, including a step of obtaining a fluororesin molded body by molding a molding material containing a fluororesin with an electromagnetic wave irradiation molding device.

[0006] The present disclosure (2) is the manufacturing method according to the present disclosure (1), wherein the electromagnetic wave irradiation molding device includes a special mold capable of molding at a temperature of 250°C or higher, and the special mold has a mold into which the molding material is charged and a heat generating part.

[0007] The present disclosure (3) is the manufacturing method according to the present disclosure (2), wherein the mold has durability against a fluororesin.

[0008] Disclosure (4) relates to a manufacturing method according to Disclosure (2) or (3) wherein the heating element comprises an electromagnetic wave absorber.

[0009] Disclosure (5) is a method for manufacturing the special mold in any combination of any of Disclosures (2) to (4), further comprising the metal mold and the heat insulating portion around the heating element.

[0010] Disclosure (6) is a manufacturing method in any combination of any of Disclosures (2) to (5) in which the special mold is heated under reduced pressure to form the molding material.

[0011] Disclosure (7) is a method for manufacturing any combination of the electromagnetic wave being a microwave as described in Disclosures (1) to (6).

[0012] This disclosure (8) states that the melt viscosity of the fluororesin is 10 4 ~10 14 This is a method for manufacturing any combination of Pa·s with any of (1) to (7) of the present disclosure.

[0013] Disclosure (9) provides a method for producing any combination of the fluororesin with any of Disclosures (1) to (8), wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, polychlorotrifluoroethylene, and ethylene / chlorotrifluoroethylene copolymer.

[0014] Disclosure (10) is a method for producing any combination of the fluororesin with any of Disclosures (1) to (9), wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, and polychlorotrifluoroethylene.

[0015] Disclosure (11) is a method for producing any combination of the fluororesin with any of Disclosures (1) to (10), wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene and polychlorotrifluoroethylene.

[0016] This disclosure (12) is a method for producing the fluororesin in any combination of any of the disclosures (1) to (11), wherein the fluororesin is polytetrafluoroethylene.

[0017] Disclosure (13) is a method for producing any combination of the fluororesin with any of Disclosures (1) to (12), wherein the fluororesin is polytetrafluoroethylene that has been heated to a temperature above its melting point.

[0018] The present disclosure (14) is a method for producing any combination of the fluororesin with any of the present disclosures (1) to (13), which is a modified polytetrafluoroethylene that has been heated to a temperature above its melting point.

[0019] This disclosure (15) is a method for producing the molding material in any combination of any of the disclosures (1) to (14), further comprising an inorganic filler.

[0020] This disclosure (16) is a method for producing the molding material in any combination of any of the disclosures (1) to (15), which is a powder.

[0021] The present disclosure (17) is a method for producing the fluororesin molded article in any combination of any of the present disclosures (1) to (16), wherein the density of the fluororesin molded article is 2.10 to 2.20 g / ml.

[0022] Disclosure (18) is a method for producing the fluororesin molded article in any combination of any of Disclosures (1) to (17), wherein the density of the fluororesin molded article is 2.14 g / ml or more.

[0023] This disclosure (19) is a method for manufacturing the fluororesin molded article in any combination of any of the disclosures (1) to (18) that include a filler.

[0024] Disclosure (20) is a fluororesin molded article obtained by a manufacturing method in any combination of any of Disclosures (1) to (19).

[0025] The present disclosure (21) is a fluororesin molded article obtained from a material containing a fluororesin, having an orientation degree of 56% or less.

[0026] The present disclosure (22) is a fluororesin molded article according to the present disclosure (21), wherein the fluororesin is polytetrafluoroethylene that has been heated to a temperature above its melting point.

[0027] The present disclosure (23) is a fluororesin molded article obtained from a material containing polytetrafluoroethylene that has been heated to a temperature above its melting point, having a density of 2.14 g / ml or more and a tensile elongation of 200% or more.

[0028] The present disclosure (24) is a fluoropolymer molded article according to the present disclosure (23), having a density of 2.16 to 2.20 g / ml and a tensile elongation of 200 to 500%.

[0029] The present disclosure (25) is a fluororesin molded article according to the present disclosure (23), wherein the polytetrafluoroethylene is a modified polytetrafluoroethylene and has a tensile elongation of 400% or more.

[0030] The present disclosure (26) is a fluoropolymer molded article according to the present disclosure (25), having a density of 2.16 to 2.20 g / ml and a tensile elongation of 400 to 500%.

[0031] The present disclosure (27) is a fluoropolymer molded article in any combination with any of the present disclosures (21) to (26) having an orientation degree of 47% or less.

[0032] The present disclosure (28) is a fluororesin molded article in any combination with any of the present disclosures (21) to (27) having an orientation degree of 5% or less.

[0033] The present disclosure (29) is a fluororesin molded article in any combination of the material being a powder with any of the present disclosures (21) to (28).

[0034] The present disclosure (30) is a fluoropolymer molded article in any combination of any of the present disclosures (21) to (29) further comprising a filler.

[0035] The present disclosure (31) is a fluoropolymer molded article used in any combination of any of the present disclosures (20) to (30) for use in at least one selected from the group consisting of lining sheets, packings, gaskets, diaphragm valves, heat-resistant wires, heat-resistant insulating tapes, release sheets, sealing materials, casings, sleeves, bellows, hoses, piston rings, butterfly valves, rectangular tanks, wafer carriers, circuit boards, nuts, bolts, fittings, semiconductor components, optical lens components, solar cell panel films, and OA rolls. [Effects of the Invention]

[0036] According to this disclosure, a method for manufacturing a fluororesin molded article and a fluororesin molded article can be provided that can be obtained with good tensile properties. [Brief explanation of the drawing]

[0037] [Figure 1] A cross-sectional view showing a special type in one embodiment of the present disclosure. [Figure 2] Small-angle X-ray diffraction pattern of the fluororesin molded body obtained in Example 2. [Figure 3] Small-angle X-ray diffraction pattern of the fluororesin molded product obtained in Comparative Example 2. [Figure 4] The annular strength distribution of the fluororesin molded articles obtained in Example 2 and Comparative Example 2. [Modes for carrying out the invention]

[0038] The following provides a detailed explanation of this disclosure.

[0039] This disclosure provides a method for manufacturing a fluororesin molded article, which includes a step of obtaining a fluororesin molded article by molding a molding material containing fluororesin with an electromagnetic wave irradiation molding apparatus.

[0040] In the manufacturing method disclosed herein, molding is performed using an electromagnetic wave irradiation molding apparatus, making it possible to obtain a fluororesin molded article with good tensile properties. Furthermore, compared to compression molding and cutting, a fluororesin molded article can be obtained in a shorter time, and molding losses can be reduced because the desired molded article can be obtained without cutting.

[0041] The molding material formed by the manufacturing method of this disclosure includes a fluororesin.

[0042] The above fluororesin has a melt viscosity of 10 4 It is preferable that it be Pa·s or higher, 5 It is more preferable that it be Pa·s or higher, 10 7 It is even more preferable that it be Pa·s or higher. 10 It is even more preferable that it be Pa·s or higher, and also 10 14 Pa·s may be used below. Conventionally, fluororesins with such high melt viscosity are processed by compression molding and cutting, which often require a lot of time. However, according to the manufacturing method of this disclosure, they can be molded in a relatively short time. The above melt viscosity is quantified using a melt viscoelasticity analyzer MCR302 (manufactured by Anton Paar Japan Co., Ltd.). A parallel plate with a diameter of 7 mm is used as the measuring fixture, and the complex viscosity measured at a deformation rate of 0.3%, a sample thickness of 0.5 mm, a temperature of 230°C or 380°C, and a frequency of 0.01 radians per second is defined as the melt viscosity. For fluororesins that melt at 230°C, the measurement is performed at 230°C, and for fluororesins that do not melt at 230°C, the measurement is performed at 380°C.

[0043] It is also preferable that the above-mentioned fluororesin does not exhibit melt-flow properties. Fluororesins that do not exhibit melt-flow properties are conventionally processed by compression molding and cutting, which often require considerable time. However, according to the manufacturing method of this disclosure, they can be molded in a relatively short time. In this specification, "not exhibiting melt fluidity" means that the melt flow rate (MFR) is less than 0.25 g / 10 min, preferably less than 0.10 g / 10 min, and more preferably 0.05 g / 10 min or less. In this specification, the MFR of fluororesins is a value obtained according to ASTM D1238, using a melt indexer, as the mass of polymer (g / 10 min) flowing out of a nozzle with an inner diameter of 2.095 mm and a length of 8 mm per 10 minutes at a measurement temperature (e.g., 372°C for PFA and FEP, and 297°C for ETFE) and load (e.g., 5 kg for PFA, FEP, and ETFE). In the case of PTFE, the value is obtained by measurement under the same measurement conditions as for PFA.

[0044] Furthermore, if a pre-molded body (unfired molded body) made by compression molding of fluororesin is heated at a temperature above the melting point of the fluororesin for one hour or more, and the decrease in thickness after heating compared to the thickness before heating is less than 20%, or if the thickness after heating is greater than the thickness before heating, it also means that the fluororesin does not exhibit melt-fluidity.

[0045] The above fluororesin preferably has an MFR of 0.25 g / 10 min or more at 372°C and a load of 5 kg, more preferably 0.5 g / 10 min or more, even more preferably 1.0 g / 10 min or more, and also preferably 100 g / 10 min or less, more preferably 90 g / 10 min or less, and even more preferably 80 g / 10 min or less.

[0046] The above fluororesins include polytetrafluoroethylene [PTFE], tetrafluoroethylene [TFE] / perfluoro(alkyl vinyl ether) [PAVE] copolymer [PFA], TFE / hexafluoropropylene [HFP] copolymer [FEP], ethylene [Et] / TFE copolymer [ETFE], Et / TFE / HFP copolymer [EFEP], polychlorotrifluoroethylene [PCTFE], chlorotrifluoroethylene [CTFE] / TFE copolymer, CTFE / TFE / PAVE copolymer, Et / C Examples include TFE copolymer [ECTFE], polyvinyl fluoride [PVF], polyvinylidene fluoride [PVdF], vinylidene fluoride [VdF] / TFE copolymer, VdF / HFP copolymer, VdF / TFE / HFP copolymer, VdF / HFP / (meth)acrylic acid copolymer, VdF / CTFE copolymer, VdF / pentafluoropropylene copolymer, VdF / PAVE / TFE copolymer, TFE / perfluoro(alkylallyl ether) copolymer, etc., which can be used individually or in combination.

[0047] Among the above fluororesins, at least one selected from the group consisting of PTFE, PFA, FEP, ETFE, PCTFE, and ECTFE is preferred, at least one selected from the group consisting of PTFE, PFA, FEP, and PCTFE is more preferred, at least one selected from the group consisting of PTFE and PCTFE is even more preferred, and PTFE is particularly preferred.

[0048] The above PTFE may be a homopolymer of TFE, or it may be a modified PTFE containing polymerization units based on 99.0% by mass or more of TFE and polymerization units based on 1.0% by mass or less of modified monomer (hereinafter also referred to as "modified monomer units"). The above modified PTFE may consist only of polymerization units based on TFE and modified monomer units.

[0049] The above modified PTFE preferably has a content of modified monomer units in the range of 0.00001 to 1.0% by mass based on all polymerization units. As the lower limit of the content of modified monomer units, 0.0001% by mass is more preferable, 0.001% by mass is further more preferable, 0.005% by mass is even more preferable, and 0.010% by mass is particularly more preferable. As the upper limit of the content of modified monomer units, 0.90% by mass is preferable, 0.50% by mass is more preferable, 0.40% by mass is further more preferable, 0.30% by mass is even more preferable, 0.20% by mass is particularly more preferable, and 0.10% by mass is particularly preferable. In the present specification, the above modified monomer unit means a part of the molecular structure of PTFE that is derived from the modified monomer.

[0050] In the present specification, the content of each polymerization unit constituting the fluororesin can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis according to the type of monomer.

[0051] The above modified monomer is not particularly limited as long as it can copolymerize with TFE. For example, perfluoroolefins such as hexafluoropropylene [HFP]; hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perhaloolefins such as chlorotrifluoroethylene; perfluorovinyl ether; perfluoroallyl ether; (perfluoroalkyl)ethylene, ethylene, etc. may be mentioned. Also, the modified monomer used may be one kind or a plurality of kinds.

[0052] The above perfluorovinyl ether is not particularly limited. For example, the following general formula (A): CF2=CF-ORf A (A) (In the formula, Rf A represents a perfluoro organic group.) Perfluoro unsaturated compounds represented by the formula and the like may be mentioned. In the present specification, the above “perfluoro organic group” means an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The above perfluoro organic group may have an ether oxygen.

[0053] As the above perfluorovinyl ether, for example, in the above general formula (A), Rf A Examples include perfluoro(alkyl vinyl ether) [PAVE], where the perfluoroalkyl group has 1 to 10 carbon atoms. Preferably, the number of carbon atoms in the perfluoroalkyl group is 1 to 5.

[0054] Examples of perfluoroalkyl groups in the above-mentioned PAVE include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, and perfluorohexyl groups.

[0055] The above perfluorovinyl ether further includes, in the above general formula (A), Rf A Those in which the group is a perfluoro(alkoxyalkyl) group with 4 to 9 carbon atoms, Rf A The formula is as follows:

[0056] [ka]

[0057] The base represented by (wherein m represents an integer from 0 to 4) is Rf. A The formula is as follows:

[0058] [ka]

[0059] Examples include the base represented by (wherein n represents an integer from 1 to 4).

[0060] (Perfluoroalkyl)ethylene (PFAE) is not particularly limited and examples include (perfluorobutyl)ethylene (PFBE) and (perfluorohexyl)ethylene.

[0061] Examples of perfluoroallyl ethers include general formula (B): CF2 = CF - CF2 - ORf B (B) (In the formula, Rf B ) represents a perfluoroorganic group. Examples include fluoromonomers represented by ).

[0062] The above Rf B The perfluoroallyl ether is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. The perfluoroallyl ether is preferably at least one selected from the group consisting of CF2=CF-CF2-O-CF3, CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9, more preferably at least one selected from the group consisting of CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9, and even more preferably CF2=CF-CF2-O-CF2CF2CF3.

[0063] The above PTFE preferably has a standard specific gravity (SSG) of 2.130 to 2.280. More preferably, the SSG is 2.220 or less, and even more preferably 2.200 or less. Furthermore, it is preferably 2.140 or more, and even more preferably 2.150 or more. The above SSG is measured using a sample molded in accordance with ASTM D 4895-89 and measured by the water displacement method in accordance with ASTM D-792.

[0064] The above-mentioned PTFE preferably has non-melt secondary processability. Non-melt secondary processability refers to the property that the melt flow rate cannot be measured at temperatures higher than the melting point, in accordance with ASTM D-1238 and D-2116, or in other words, the property that does not easily flow even in the melting temperature range.

[0065] The PTFE described above may have a history of being heated to a temperature above its melting point. Even when using recycled PTFE or other PTFE that has a history of being heated to a temperature above its melting point, it is difficult to obtain a molded article with tensile properties equivalent to that of a molded article made from PTFE that has not been heated to a temperature above its melting point, even when compression molding is performed. According to the manufacturing method of this disclosure, even when using PTFE that has a history of being heated to a temperature above its melting point, a molded article with excellent tensile properties can be obtained. Examples of the above-mentioned heating include heating for molding, heat treatment, and the like.

[0066] The PTFE described above preferably has one or more melting points in the temperature range below 333°C. The temperature range below 333°C is more preferably below 332°C, even more preferably below 331°C, preferably 250°C or higher, and more preferably 300°C or higher. A melting point within the above range indicates that the material has been heated to a temperature above its melting point. In this specification, the melting point of a fluoropolymer is the temperature corresponding to the minimum point in the heat of fusion curve obtained when the temperature is increased at a rate of 10°C / min using a differential scanning calorimeter (DSC). If there are two or more minimum points in a single melting peak, each of them shall be considered a melting point.

[0067] The PTFE mentioned above may not have a history of being heated to a temperature above its melting point. In this case, it is preferable that the PTFE has one or more melting points in the temperature range of 333 to 360°C. The temperature range is more preferably 334°C or higher, even more preferably 335°C or higher, even more preferably 355°C or lower, and even more preferably 350°C or lower. The fact that the melting point is within the above range indicates that there is no history of heating to a temperature above the melting point. In addition to the melting point mentioned above, the substance may also have a melting point in the temperature range below 333°C.

[0068] The above PFA is not particularly limited, but a copolymer in which the molar ratio of TFE units to PAVE units (TFE units / PAVE units) is 70 / 30 or more and less than 99 / 1 is preferred. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and an even more preferred molar ratio is 80 / 20 or more and 98.9 / 1.1 or less. The above PFA is also preferably a copolymer in which monomer units derived from monomers copolymerizable with TFE and PAVE are 0.1 to 10 mol% (TFE units and PAVE units totaling 90 to 99.9 mol%), more preferably 0.1 to 5 mol%, and particularly preferably 0.2 to 4 mol%.

[0069] Monomers copolymerizable with TFE and PAVE include HFP and formula (I):CZ 1 Z 2 =CZ 3 (CF2) n Z 4 (In the formula, Z 1 , Z 2 and Z 3 Z represents a hydrogen atom or a fluorine atom, either identical or different. 4 ∫ represents a hydrogen atom, a fluorine atom, or a chlorine atom, and n is an integer from 2 to 10. ) Vinyl monomer represented by formula (II): CF2 = CF-OCH2-Rf 1 (In the formula, Rf 1 CZ represents a perfluoroalkyl group having 1 to 5 carbon atoms. ) Alkyl perfluorovinyl ether derivatives represented by formula (III):CZ 5 Z 6 =CZ 7 -CZ 8 Z 9 -O-Rf 2 (In the formula, Z 5 , Z 6 and Z 7 Z represents a hydrogen atom, a chlorine atom, or a fluorine atom, either identical or different. 8 and Z 9 Rf represents a hydrogen atom or a fluorine atom. 2 CH2=CFCF2-O-Rf 3CF2 = CFCF2 - O - Rf 3 (Perfluoroalkyl allyl ether), CF2=CFCH2-O-Rf 3 CH2=CHCF2-O-Rf 3 (In the formula, Rf 3 Examples of which are the same as in formula (III) above include the following. Furthermore, monomers copolymerizable with TFE and PAVE include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, and acid anhydrides of unsaturated dicarboxylic acids, such as itaconic acid, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride.

[0070] The above PFA preferably has a melting point of 180 to less than 324°C, more preferably 230 to 320°C, and even more preferably 280 to 320°C.

[0071] The above PFA preferably has an MFR of 0.25 g / 10 min or more and 100 g / 10 min or less, more preferably 0.5 g / 10 min or more, even more preferably 1.0 g / 10 min or more, even more preferably 90 g / 10 min or less, and even more preferably 80 g / 10 min or less. The MFR of PFA is obtained according to ASTM D1238 as the mass of polymer (g / 10 min) flowing out of a nozzle with an inner diameter of 2.095 mm and a length of 8 mm per 10 minutes, using a melt indexer at a measurement temperature of 372°C and a load of 5 kg.

[0072] The above FEP is not particularly limited, but a copolymer in which the molar ratio of TFE units to HFP units (TFE units / HFP units) is 70 / 30 or more and less than 99 / 1 is preferred. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and an even more preferred molar ratio is 80 / 20 or more and 98.9 / 1.1 or less. The above FEP is also preferably a copolymer in which monomer units derived from monomers copolymerizable with TFE and HFP are 0.1 to 10 mol% (TFE units and HFP units totaling 90 to 99.9 mol%), more preferably 0.1 to 5 mol%, and particularly preferably 0.2 to 4 mol%.

[0073] Monomers copolymerizable with TFE and HFP include PAVE, monomers represented by formula (III), and alkyl perfluorovinyl ether derivatives represented by formula (II). Furthermore, monomers copolymerizable with TFE and HFP include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, and acid anhydrides of unsaturated dicarboxylic acids, such as itaconic acid, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride.

[0074] The above FEP preferably has a melting point of 150 to less than 324°C, more preferably 200 to 320°C, and even more preferably 240 to 320°C.

[0075] The above FEP preferably has an MFR of 0.25 g / 10 min or more and 100 g / 10 min or less, more preferably 0.5 g / 10 min or more, even more preferably 1.0 g / 10 min or more, even more preferably 80 g / 10 min or less, and even more preferably 60 g / 10 min or less. The MFR of FEP is obtained according to ASTM D1238 as the mass of polymer (g / 10 min) flowing out of a nozzle with an inner diameter of 2.095 mm and a length of 8 mm per 10 minutes, using a melt indexer at a measurement temperature of 372°C and a load of 5 kg.

[0076] Examples of the above-mentioned PCTFE include CTFE homopolymers and copolymers containing polymerization units based on CTFE ("CTFE units") and polymerization units based on a monomer (α) polymerizable with CTFE ("monomer (α) units").

[0077] The above PCTFE preferably has a CTFE unit content of 90 to 100 mol%, more preferably 98 to 100 mol%, and even more preferably 99 to 100 mol%.

[0078] When the above PCTFE is a copolymer containing CTFE units and monomer (α) units, the monomer (α) is not particularly limited as long as it is a monomer copolymerizable with CTFE, for example, tetrafluoroethylene (TFE), ethylene (Et), vinylidene fluoride (VdF), perfluoro(alkyl vinyl) ether (PAVE), and the following general formula (1): CX 3 X 4 =CX 1 (CF2) n X 2 (1) (In the formula, X 1 , X 3 and X 4 X represents a hydrogen atom or a fluorine atom, either identical or different. 2 ) represents a hydrogen atom, a fluorine atom, or a chlorine atom, and n represents an integer from 1 to 10. ) A vinyl monomer represented by the following general formula (2) CF2 = CF - OCH2 - Rf 4 (2) (In the formula, Rf 4 Examples include alkyl perfluorovinyl ether derivatives represented by perfluoroalkyl groups having 1 to 5 carbon atoms.

[0079] Examples of the above-mentioned PAVEs include perfluoro(methyl vinyl ether) [PMVE], perfluoro(ethyl vinyl ether) [PEVE], perfluoro(propyl vinyl ether) [PPVE], and perfluoro(butyl vinyl ether).

[0080] The vinyl monomer represented by the above general formula (1) is not particularly limited, but examples include hexafluoropropylene (HFP), perfluoro(1,1,2-trihydro-1-hexene), perfluoro(1,1,5-trihydro-1-pentene), and the following general formula (3): H2C=CX 5 Rf 5 (3) (In the formula, X 5 is H, F, or CF3, and Rf 5Examples include perfluoro(alkyl)ethylene, which is a perfluoroalkyl group having 1 to 10 carbon atoms. Perfluoro(butyl)ethylene is preferred as the above perfluoro(alkyl)ethylene.

[0081] The alkyl perfluorovinyl ether derivative represented by the above general formula (2) is Rf 4 It is preferable that the group is a perfluoroalkyl group having 1 to 3 carbon atoms, and more preferably CF2=CF-OCH2-CF2CF3.

[0082] The monomer (α) polymerizable with the above CTFE is preferably at least one selected from the group consisting of TFE, Et, VdF, PAVE, and vinyl monomers represented by the above general formula (1). Furthermore, the above monomer (α) may be one type or two or more types.

[0083] As the monomer (α) above, unsaturated carboxylic acids copolymerizable with CTFE may also be used. The unsaturated carboxylic acids are not particularly limited and include, for example, unsaturated aliphatic carboxylic acids having 3 to 6 carbon atoms such as (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and aconitic acid, and may also be unsaturated aliphatic polycarboxylic acids having 3 to 6 carbon atoms.

[0084] The above-mentioned unsaturated aliphatic polycarboxylic acids are not particularly limited and include, for example, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, aconitic acid, etc. Acid anhydrides that can be produced, such as maleic acid, itaconic acid, and citraconic acid, may also be acid anhydrides.

[0085] The monomer (α) described above may consist of two or more types, but if one of them is VdF, PAVE and / or HFP, it does not need to be used in combination with itaconic acid, citraconic acid and their acid anhydrides.

[0086] The above PCTFE preferably has a melting point of 205 to 225°C, and more preferably 210 to 216°C.

[0087] The above PCTFE has a flow value of 1 × 10⁻⁶ -5 It is preferable that the concentration is (cc / s) or higher, and 1 × 10 -4 It is more preferable that it be (cc / s) or more, 5 × 10 -4 It is even more preferable that it be (cc / s) or more. Also, it is preferable that it be 1 (cc / s) or less, and 1 × 10 -2 It is more preferable that it be (cc / s) or less, 5 × 10 -3 It is even more preferable that it be (cc / s) or less. The flow values ​​mentioned above were measured using an elevated flow tester, with a measurement temperature of 230°C, a load of 980N, and a nozzle diameter of 1mmφ.

[0088] The above-mentioned fluororesin can also be a combination of several different fluororesins. For example, several fluororesins with different constituent monomers may be used in combination, an unfired fluororesin and a fired fluororesin may be used in combination, or a fluororesin that does not exhibit melt-flow properties and a fluororesin that does exhibit melt-flow properties may be used in combination. The method of mixing the several fluororesins is not particularly limited, and known methods can be used. The mixing may be carried out dry or wet, but dry mixing is preferred. It is more preferable to mix powders of several fluororesins together.

[0089] The fluororesin content is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95.0% by mass or more, even more preferably 98.0% by mass or more, even more preferably 98.5% by mass or more, even more preferably 99.0% by mass or more, even more preferably 99.5% by mass or more, even more preferably 99.9% by mass or more, and particularly preferably 99.99% by mass or more, and may also be 100% by mass or less.

[0090] The above-mentioned molding material may or may not contain fillers. Examples of fillers include inorganic fillers such as glass fibers, glass beads, carbon fibers, spherical carbon, carbon black, graphite, carbon nanotubes (CNTs), silica, alumina, mica, silicon carbide, boron nitride, aluminum nitride, magnesium oxide, titanium oxide, bismuth oxide, cobalt oxide, molybdenum disulfide, bronze, gold, silver, copper, and nickel; and organic fillers such as aromatic polyesters, polyimides, and polyphenylene sulfide. One or more of these can be used. Inorganic fillers are preferred, and conductive fillers or thermally conductive fillers are also preferred.

[0091] Since the above-mentioned filler yields a molded article with excellent properties such as electrical conductivity and thermal conductivity, it is preferable that the aspect ratio be 10 or more, more preferably 50 or more, and may be 1000 or less. The manufacturing method of this disclosure makes it possible to obtain a molded article with excellent properties such as electrical conductivity and thermal conductivity, even when using a filler with a high aspect ratio as described above. The above aspect ratio can be calculated from images measured by a transmission electron microscope (TEM) or an atomic force microscope (AFM).

[0092] The content of the above filler is preferably 80% by mass, more preferably 60% by mass or less, even more preferably 40% by mass or less, even more preferably 20% by mass or less, even more preferably 10% by mass or less, even more preferably 5.0% by mass or less, even more preferably 2.0% by mass or less, even more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, and especially preferably 0.5% by mass or less. It may also be 0% by mass or more, preferably 0.01% by mass or more, and more preferably 0.1% by mass or more.

[0093] It is also preferable to use a conductive filler as the above-mentioned filler. When materials containing conductive fillers are molded by methods such as compression molding or extrusion molding, there is a problem that the conductivity is not fully exhibited. In the manufacturing method of this disclosure, molding is performed using microwaves, so even when conductive fillers are used, a molded article with excellent conductivity can be obtained. This is thought to be because, in microwave molding, the resin can be molded without flowing, so the conductive filler is less likely to aggregate or be damaged, and a good conductive path is maintained.

[0094] Examples of the conductive fillers mentioned above include carbon fillers and metal-based fillers. Carbon fillers and metal-based fillers may be used in combination.

[0095] Examples of the above-mentioned carbon fillers include carbon black, graphite, graphene sheets, carbon nanotubes (CNTs), carbon nanostructures, carbon nanofibers, PAN-based carbon fibers, pitch-based carbon fibers, etc., and one or more of these can be used.

[0096] Examples of the above-mentioned metal-based fillers include metal powders such as iron, silver, copper, stainless steel, aluminum, and nickel; conductive metal oxide powders such as zirconium oxide; these metal fibers; conductive metal oxide fibers; and metal-coated synthetic fibers.

[0097] As the conductive filler mentioned above, carbon fillers are preferred, and carbon nanotubes are more preferred.

[0098] The carbon nanotubes described above may be multilayered or single-walled, but single-walled carbon nanotubes are particularly preferred. Single-walled carbon nanotubes are preferred because they have particularly excellent conductive properties.

[0099] The single-walled carbon nanotubes described above are a special type of carbon material known as one-dimensional materials. Single-walled carbon nanotubes consist of sheets of graphene that are rolled to form hollow tubes with walls one atom thick. Due to their chemical structure and size, single-walled carbon nanotubes exhibit excellent mechanical, electrical, thermal, and optical properties.

[0100] The average diameter of the carbon nanotubes is preferably 1000 nm or less, more preferably 800 nm or less, even more preferably 500 nm or less, even more preferably 300 nm or less, particularly preferably 200 nm or less, and also preferably 0.1 nm or more, more preferably 0.5 nm or more, and even more preferably 1.0 nm or more. The average diameter of the carbon nanotubes mentioned above can be determined from the optical absorption spectrum, Raman spectrum, transmission electron microscope (TEM), or atomic force microscope (AFM) images of the carbon nanotubes obtained by ultraviolet-visible near-infrared spectroscopy (UV-Vis-NIR).

[0101] The average fiber length of the carbon nanotubes is preferably less than 100 μm, more preferably 50 μm or less, even more preferably 20 μm or less, even more preferably 10 μm or less, and also preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The average fiber length of the carbon nanotubes can be determined by obtaining an AFM image of the carbon nanotubes using an atomic force microscope (AFM), or by obtaining a TEM image of the carbon nanotubes using a transmission electron microscope (TEM), measuring the length of each carbon nanotube, and dividing the sum of the lengths by the number of carbon nanotubes measured.

[0102] The G / D ratio of the above carbon nanotube, as measured by Raman spectroscopy (wavelength 532 nm), is preferably 0.5 or higher, more preferably 0.8 or higher, even more preferably 1.0 or higher, and also preferably 250 or lower, more preferably 200 or lower, and even more preferably 150 or lower. The G / D ratio is the ratio of the intensity of the G band to the D band in the Raman spectrum of a carbon nanotube (G / D). A higher G / D ratio of a carbon nanotube indicates higher crystallinity and fewer impurities and defects in the carbon nanotube.

[0103] Furthermore, carbon nanotubes with a very large G / D ratio of 90 or more are also known, and such carbon nanotubes can also be suitably used. Carbon nanotubes with a large G / D ratio are particularly preferable because they can impart conductivity with a small content, and can exhibit good surface smoothness and stress crack resistance in molded articles.

[0104] Commercially available carbon nanotubes can be used as described above. Examples of commercially available single-walled carbon nanotubes include TUBALL from OCSiAl and ZEONANO from Zeon Corporation, while examples of multi-walled carbon nanotubes include TPR carbon nanotubes, NC7000 from Nanocyl, FT6000 series from Canno, and K-nano400 from Kumho Petrochemical.

[0105] The content of the conductive filler is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, even more preferably 0.5% by mass or less, and may be 0% by mass or more, preferably 0.01% by mass or more, and even more preferably 0.05% by mass or more, based on the total amount of the fluororesin and the conductive filler. As described above, good conductivity can be imparted even with a relatively small amount of conductive filler, thus enabling conductivity without impairing moldability or the mechanical strength of the molded product. Furthermore, it can be suitably used in applications where the use of large amounts of conductive filler is undesirable due to concerns about conductive filler leaching.

[0106] It is also preferable to use a thermally conductive filler as the above-mentioned filler. When materials containing a thermally conductive filler are molded by methods such as compression molding or extrusion molding, there is a problem that the thermal conductivity is not fully exhibited. In the manufacturing method of this disclosure, since molding is performed using microwaves, a molded body with excellent thermal conductivity can be obtained even when a thermally conductive filler is used. This is thought to be because, in microwave molding, the resin can be molded without flowing, so the thermally conductive filler is less likely to aggregate or be damaged, and a good heat conduction path is maintained.

[0107] Examples of the above-mentioned thermally conductive fillers include boron nitride, aluminum nitride, magnesium oxide, and alumina, and one or more of these can be used. Among these, boron nitride is preferred.

[0108] The content of the above-mentioned thermal conductive filler is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.0% by mass or less, even more preferably 0.5% by mass or less, and may be 0% by mass or more, preferably 0.01% by mass or more, and even more preferably 0.05% by mass or more, based on the total amount of the above-mentioned fluororesin and the above-mentioned thermal conductive filler. As described above, even with a relatively small amount of thermally conductive filler, good thermal conductivity can be imparted, thus allowing for the provision of thermal conductivity without compromising moldability or the mechanical strength of the molded product. Furthermore, it can be suitably used in applications where the use of large amounts of thermally conductive filler is undesirable due to concerns about filler leaching.

[0109] The method for mixing the above-mentioned fluororesin and the above-mentioned filler is not particularly limited, and known methods can be used. The mixing may be carried out dry or wet, but dry mixing is preferred. It is more preferable to mix the above-mentioned fluororesin powder with the above-mentioned filler powder.

[0110] To improve the dispersibility of the filler and to facilitate the expression of the filler's properties in the molded article, it is preferable to compound the fluororesin and the filler to form compound particles. In particular, compounding is preferable when the filler is a conductive filler. The compounding method is not limited, but examples include compounding by mixing the fluororesin and the filler while applying high mechanical energy, or compounding by supplying a supercritical fluid such as supercritical carbon dioxide to a slurry containing the fluororesin and the filler. Methods for mixing while applying high mechanical energy include methods such as shearing, compression, stretching, grinding, friction, kneading, mixing, dispersion, crushing, and shaking. These methods may or may not involve chemical reactions. As a method of mixing while applying the high mechanical energy mentioned above, a method of mixing using a friction mill can also be mentioned. The friction mill is a device that arranges multiple blades on the outer circumference of a rotating shaft inside a drum, and rotates these blades to generate centrifugal diffusion and vortex flow, thereby causing the powder to flow within the drum. An example of such a device is the one described in Japanese Patent Publication No. 2010-180099.

[0111] The fluororesin to be mixed with the above-mentioned filler is preferably a particle obtained by compression molding or melting and pulverizing. This increases the hardness of the fluororesin particles and improves the dispersibility of the filler in the resulting molded article. Furthermore, the dispersibility of the filler can be further improved by compounding the fluororesin particles obtained in this way with the above-mentioned filler using a friction mill. One preferred embodiment of this disclosure is that the above-mentioned molding material includes composite particles obtained by compression molding or melting and grinding the above-mentioned fluororesin particles and the above-mentioned filler, which are compounded by a friction mill.

[0112] The above molding material preferably contains substantially no filler. "Substantially no filler" means that the filler content is less than 0.01% by mass, preferably less than 0.001% by mass, relative to the total amount of the fluororesin and the filler. The lower limit is not limited and may be 0% by mass.

[0113] The form of the molding material described above is not particularly limited and may be a powder, pellets, etc., but it is preferably a powder.

[0114] The molding of the above-mentioned molding material is carried out using an electromagnetic wave irradiation molding apparatus. The electromagnetic waves that can be used in the above-mentioned electromagnetic wave irradiation molding apparatus are preferably those including a wavelength range of 0.01 to 100 m. Examples of such electromagnetic waves include electromagnetic waves including a wavelength range of 0.01 to 1 m (microwaves) and electromagnetic waves including a wavelength range of 1 to 100 m (high frequency), with microwaves being particularly preferred.

[0115] The electromagnetic wave irradiation molding apparatus described above is equipped with a special mold capable of molding at temperatures of 250°C or higher, and preferably the special mold has a metal mold into which the molding material is fed and a heating element. By using such a special mold, even high-melting-point fluororesins that are difficult to mold with rubber molds (heat resistance temperature of about 250°C) can be molded.

[0116] The above-described metal mold functions as a molding die. Because metal has excellent thermal conductivity, it effectively conducts heat from the heat-generating part to the molding material, allowing for the effective molding of even fluororesins with high melting points. Furthermore, using metal improves the heat resistance of the molding die.

[0117] The metal in the above metal mold is preferably one or more selected from the group consisting of, for example, aluminum, iron, copper, and alloys containing these. The alloy may be any alloy containing one or more of aluminum, iron, or copper, for example, brass (copper-zinc alloy).

[0118] The above-mentioned metal mold preferably has durability against fluororesin. More specifically, it is preferable that the mold is resistant to deterioration due to corrosion, etc., even when the fluororesin is molded at a temperature above its melting point. The above metal mold preferably has a material and / or surface treatment layer that takes into consideration durability against fluororesin, and more preferably has a material and / or surface treatment layer that takes into consideration durability against fluororesin. Examples of the materials mentioned above include SUS420J2 modified steel materials such as STAVAX (manufactured by Uddeholm) and HPM38 (manufactured by Proterial); alloy tool steels such as SKD11, SKD12, SKD61, and SK3; and NAK (manufactured by Daido Steel Co., Ltd.). Examples of the surface treatment layer include electrolytic plating and electroless plating of nickel, hard chromium, etc. The above surface treatment layer may be combined with various metals that can be used in the metal molds described above, or with materials that have been chosen for their durability against the fluororesin.

[0119] Preferably, the metal mold has an internal space into which the molding material is filled. Furthermore, preferably, the metal mold is composed of a plurality of members that can move relative to each other (for example, slide relative to each other), and has an internal space surrounded by these members. In this embodiment, the volume of the internal space can be adjusted by the relative movement of the plurality of members. More specifically, the metal mold preferably has a first mold portion having a convex portion and a second mold portion having a concave portion, wherein the convex portion of the first mold portion and the concave portion of the second mold portion are configured to slide relative to each other in the depth direction of the concave portion, and an internal space is formed between the first mold portion and the second mold portion in which the molding material is filled.

[0120] The heating element described above is capable of heating the metal mold, and is preferably a heating element that generates heat by absorbing electromagnetic waves.

[0121] The heating element preferably contains an electromagnetic wave absorber. Examples of electromagnetic wave absorbers include materials containing one or more components selected from the group consisting of barium titanate, aluminum oxide, silicon oxide, carbon (graphite or carbon), carbon black, carbon nanofiber, charcoal powder, graphene, carbon nanotubes, pigments such as cyanine compounds, phthalocyanine compounds, dithiol metal complexes, naphthoquinone compounds, diinmonium compounds, azo compounds, ferrite, lead zirconate titanate (PZT), silicon carbide, mullite, and petalite, with silicon carbide being particularly preferred.

[0122] The heating element is preferably arranged on the outer circumference of the metal mold. The position and number of heating elements are not limited, but for example, if the metal mold has a hexahedral shape, it is preferable that they be arranged on at least one face, preferably on at least two opposing faces (for example, the top and bottom faces, or two opposing faces on the sides), and may be arranged on three or more faces (for example, the top and bottom faces and two opposing faces on the sides), or on all faces.

[0123] The above-described special mold further preferably has an insulating section around the metal mold and the heating element. The insulating section suppresses heat dissipation from the space in which the metal mold and the heating element are arranged, and can promote the temperature rise of the metal mold. As a result, even fluororesins with high melting points can be suitably molded. The above-mentioned heat insulating portion is preferably made of a material that can exhibit a heat insulating effect and can transmit at least a portion of electromagnetic waves.

[0124] The above-mentioned heat insulating section is preferably arranged around the unit including the metal mold and the heat-generating section, and is more preferably arranged such that the heat-generating section is not visible from any angle (preferably so that the unit is not visible).

[0125] The electromagnetic wave irradiation molding apparatus described above preferably further includes an electromagnetic wave generator. The electromagnetic wave generator is preferably capable of generating electromagnetic waves including a wavelength range of 0.01 to 100 m. In other words, it is preferable that the wavelength range of the generated electromagnetic waves is within the range of 0.01 to 100 m. Within this wavelength range, absorption of electromagnetic waves by the heat insulating section can be suppressed, and heat can be efficiently generated from the heat heating section. Preferably, the electromagnetic wave generator described above is capable of generating electromagnetic waves (microwaves) including a wavelength range of 0.01 to 1 m, or electromagnetic waves (high frequency) including a wavelength range of 1 to 100 m.

[0126] An example of a special mold that can be used in the manufacturing method of this disclosure is shown in Figure 1, but is not limited thereto. In Figure 1, the cavity 10 can also be called a mold and has an internal space 15 into which the raw material to be molded is filled. By molding the raw material, a molded body having a shape corresponding to the shape of the internal space 15 is obtained. The cavity 10 is made of metal, which allows for efficient conduction of heat from the heating elements 21 and 22 (described later) to the raw materials in the internal space 15, and also improves the heat resistance of the cavity 10. The cavity 10 is divided into multiple components (two in the example of Figure 1) and is composed of a combination of a first mold section 11 and a second mold section 12. In the example of Figure 1, an internal space 15 for filling with raw material is formed between the pair of first mold sections 11 and second mold sections 12. The cavity 10 is configured such that the volume of the internal space 15 surrounded by the multiple members (in this case, the first mold part 11 and the second mold part 12) can be changed by the relative movement of the multiple members that constitute the cavity 10. In the example shown in Figure 1, the first mold section 11 and the second mold section 12 are configured to slide relative to each other. When the first mold section 11 and the second mold section 12 slide closer to each other, the volume of the internal space 15 decreases. Here, the first mold portion 11 has a convex portion, and the second mold portion 12 has a concave portion. When the convex portion of the first mold portion 11 and the concave portion of the second mold portion 12 slide relative to each other in the depth direction of the concave portion, the inner surface of the concave portion of the second mold portion 12 can guide the movement of the convex portion of the first mold portion 11. When the first mold section 11 and the second mold section 12 move closer to each other, the volume of the internal space 15 decreases, and the raw material inside the internal space 15 is pressed between the first mold section 11 and the second mold section 12. This allows the raw material to take on a shape corresponding to the shape of the internal space 15. Cavity 10 corresponds to the metal mold described above.

[0127] In Figure 1, the heating elements 21 and 22 absorb electromagnetic waves and generate heat, and are located on the outside of the cavity 10. Heating element 21 is located on the rear side of the first mold section 11, as viewed from the internal space 15. Heating element 22 is located on the rear side of the second mold section 12, as viewed from the internal space 15. The heating elements 21 and 22 correspond to the heating sections described above.

[0128] In Figure 1, the thermal insulation materials 31, 32, 33, and 34 are made of a material that can provide thermal insulation and transmit at least a portion of the electromagnetic waves generated from an electromagnetic wave generator (not shown), and are arranged around the unit consisting of the cavity 10 and the heating elements 21 and 22. The presence of the insulating materials 31, 32, 33, and 34 suppresses heat dissipation from the enclosed interior (where the unit consisting of the cavity 10 and heating elements 21 and 22 is located) and promotes a temperature rise in the cavity 10. This allows for suitable molding even when the raw material has a high melting point. From this viewpoint, it is preferable that the insulating materials 31, 32, 33, and 34 be arranged around the unit consisting of the cavity 10 and heating elements 21 and 22 so that the heating elements 21 and 22 are not visible from any angle (preferably so that the unit consisting of the cavity 10 and heating elements 21 and 22 is not visible). The insulation materials 31, 32, 33, and 34 correspond to the insulation sections described above.

[0129] In the manufacturing method of the present disclosure, molding is preferably carried out under reduced pressure conditions. The molding pressure (gauge pressure) is preferably -70kPa or less, more preferably -75kPa or less, even more preferably -80kPa or less, even more preferably -85kPa or less, and also preferably -100kPa or more, more preferably -95kPa or more, and even more preferably -90kPa or more.

[0130] The molding temperature can be determined according to the fluororesin being molded, but for example, it is preferably above the melting point of the fluororesin, more preferably 5°C higher than the melting point of the fluororesin, even more preferably 10°C higher than the melting point of the fluororesin, and also preferably 50°C higher or lower than the melting point of the fluororesin, more preferably 40°C higher or lower than the melting point of the fluororesin, and even more preferably 30°C higher or lower than the melting point of the fluororesin.

[0131] In the manufacturing method of this disclosure, it is preferable to heat the special mold under reduced pressure conditions to form the molding material. The preferred pressure and temperature are as described above.

[0132] The molding time (the time to maintain the temperature after raising it to a predetermined molding temperature) can be determined according to the size of the target fluororesin molded article, but for example, 10 seconds or more is preferred, 1 minute or more is more preferred, 3 minutes or more is even more preferred, 4 minutes or more is even more preferred, and 2 hours or less is preferred, 1 hour or less is more preferred, 30 minutes or less is even more preferred, and 15 minutes or less is even more preferred.

[0133] The manufacturing method of the present disclosure may further include, if necessary, a step of cooling the fluororesin molded article.

[0134] The manufacturing method of this disclosure can, for example, produce a fluororesin molded article with high density and good tensile properties. Furthermore, since the manufacturing method of this disclosure does not require cutting, it is possible to obtain fluororesin molded articles with smooth surfaces or molded articles with complex shapes. A fluororesin molded article obtained by the manufacturing method of this disclosure is also one of the disclosures.

[0135] The fluororesin molded article obtained by the manufacturing method of this disclosure preferably has a tensile strength of 14 MPa or more, more preferably 17 MPa or more, more preferably 20 MPa or more, even more preferably 25 MPa or more, even more preferably 30 MPa or more, even more preferably 35 MPa or more, and particularly preferably 40 MPa or more. The upper limit is not particularly limited, but may be, for example, 60 MPa or 50 MPa. The above tensile strength shall be measured in accordance with ASTM D1708.

[0136] The fluororesin molded articles obtained by the manufacturing method of this disclosure preferably have a tensile elongation of 80% or more, more preferably 100% or more, even more preferably 200% or more, even more preferably 220% or more, even more preferably 250% or more, even more preferably 280% or more, even more preferably 300% or more, even more preferably 350% or more, even more preferably 380% or more, even more preferably 400% or more, and particularly preferably 450% or more. The upper limit is not particularly limited, but may be, for example, 600% or 500%. The above tensile elongation shall be measured in accordance with ASTM D1708.

[0137] The fluororesin molded article obtained by the manufacturing method of this disclosure preferably has a density of 2.10 g / ml or more, more preferably 2.14 g / ml or more, even more preferably 2.15 g / ml or more, even more preferably 2.16 g / ml or more, and particularly preferably 2.17 g / ml or more. The upper limit is not particularly limited, but may be, for example, 2.20 g / ml. The above density is measured by the liquid weighing method in accordance with JIS Z 8807.

[0138] The manufacturing method of this disclosure also yields a fluororesin molded article with a low degree of orientation. Fluororesins have a long-period lamellar structure in which regularly crystalline regions and disordered amorphous regions are stacked alternately. Molded articles obtained by commonly used molding methods for fluororesins, such as injection molding, extrusion molding, and compression molding, tend to exhibit anisotropy due to the orientation of the polymer chains. The fluororesin molded articles obtained by the manufacturing method of this disclosure tend to exhibit less anisotropy in the long-period structure and have a lower degree of orientation.

[0139] The fluororesin molded articles obtained by the manufacturing method of this disclosure preferably have an orientation degree of 47% or less, more preferably 35% or less, even more preferably 25% or less, even more preferably 15% or less, and particularly preferably 5% or less. The lower limit is not particularly limited, but may be, for example, 0%. The degree of orientation described above is obtained by observing a fluororesin molded product using small-angle X-ray diffusion (SAXS) or ultra-small-angle X-ray diffusion (USAXS), reading the small-angle X-ray diffraction pattern with image analysis software, and obtaining the annular intensity distribution. Using this annular intensity distribution, the degree of orientation is calculated using the following formula. The SAXS or USAXS method can be performed in accordance with the descriptions in "Polymer X-ray Diffraction: Angle Analysis" by Masao Kasai and Nobutami Kasai, Maruzen Co., Ltd., 1968, and "Polymer X-ray Diffraction: Angle Analysis" by Toru Masuko, 3.3, Yamagata University Co-op, 1995.

number

[0140] The fluororesin molded article obtained by the manufacturing method of the present disclosure may also preferably contain a filler. Examples of the filler include those that can be used in the manufacturing method of the present disclosure. The filler is preferably a conductive filler or a thermally conductive filler in that it can impart excellent electrical conductivity or thermal conductivity.

[0141] This disclosure also provides a fluororesin molded article (hereinafter also referred to as "fluororesin molded article (1) of this disclosure") obtained from a material containing a fluororesin and having an orientation degree of 56% or less. The fluororesin molded article (1) of this disclosure has a low degree of orientation, so the physical properties of the molded article are not anisotropic and uniform. Specifically, the tensile properties do not change significantly in the orientation direction and the direction perpendicular to it, the shrinkage rate is uniform, and the optical properties are not polarized.

[0142] The fluororesin in the fluororesin molded article (1) of this disclosure is the same as the fluororesin in the molding material molded by the manufacturing method of this disclosure. The fluororesin in the fluororesin molded article (1) of this disclosure is preferably at least one selected from the group consisting of perhalo resins, ETFE and ECTFE, more preferably at least one selected from the group consisting of perfluororesins, PCTFE, ETFE and ECTFE, even more preferably at least one selected from the group consisting of PTFE, PFA, FEP, ETFE, PCTFE and ECTFE, even more preferably at least one selected from the group consisting of PTFE, PFA, FEP and PCTFE, and PTFE is particularly preferred. The PTFE is preferably PTFE that has a history of being heated to a temperature above its melting point.

[0143] As the fluororesin in the fluororesin molded article (1) of this disclosure, perhalo resins are also preferred, and at least one selected from the group consisting of PTFE, PFA, FEP and PCTFE is more preferred. Perfluororesin is also preferred as the fluororesin in the fluororesin molded article (1) of this disclosure. In the fluororesin molded article (1) of this disclosure, at least one selected from the group consisting of PTFE, PFA, and PCTFE is particularly preferred as the fluororesin.

[0144] The fluororesin in the fluororesin molded article (1) of this disclosure is preferably a fluororesin that is insoluble in the solvent. In this specification, a person skilled in the art will be able to clearly understand the scope of a fluororesin that is insoluble in the solvent. Examples of the above-mentioned solvent-insoluble fluororesin include at least one selected from the group consisting of PTFE, PFA, FEP, PCTFE, ETFE, EFEP, and ECTFE.

[0145] The fluororesin molded article (1) of this disclosure has an orientation degree of 56% or less, but is preferably 47% or less, more preferably 35% or less, even more preferably 25% or less, even more preferably 15% or less, and particularly preferably 5% or less. The lower limit is not particularly limited, but may be, for example, 0%.

[0146] The fluororesin molded article (1) of this disclosure is preferably obtained by a processing method that includes a step of heating the fluororesin to a temperature above its melting point. The fluororesin molded article (1) of this disclosure is also preferably obtained by a processing method that does not use a solvent. The fluororesin molded article (1) of this disclosure is also preferably not a cast film (a film obtained by a solvent casting method).

[0147] The fluororesin molded article (1) of this disclosure preferably has a maximum thickness of 10 μm or more, more preferably 0.1 mm or more, and even more preferably 1 mm or more. The upper limit is not particularly limited and may be 1 m or more. The above maximum thickness can be measured using a thickness gauge, ruler, or tape measure.

[0148] This disclosure also provides a fluororesin molded article (hereinafter also referred to as the fluororesin molded article (2) of this disclosure) obtained from a material containing PTFE that has been heated to a temperature above its melting point, and having a density of 2.14 g / ml or more and a tensile elongation of 200% or more. The fluoropolymer molded article (2) of this disclosure has high density and good tensile properties despite using PTFE that has been heated to a temperature above its melting point.

[0149] In this specification, unless otherwise specified, the fluoropolymer molded articles (1) and (2) of this disclosure shall be collectively referred to as "fluoropolymer molded articles of this disclosure." Examples of PTFE-containing materials in the fluoropolymer molded articles of this disclosure that have been heated to a temperature above their melting point include those described as molding materials in the manufacturing method of this disclosure.

[0150] The fluororesin molded articles of this disclosure have a density of 2.14 g / ml or more, preferably 2.15 g / ml or more, more preferably 2.16 g / ml or more, and even more preferably 2.17 g / ml or more. The upper limit is not particularly limited, but may be, for example, 2.20 g / ml.

[0151] The fluororesin molded articles of this disclosure have a tensile elongation of 200% or more, but are preferably 220% or more, more preferably 250% or more, even more preferably 280% or more, even more preferably 300% or more, even more preferably 350% or more, even more preferably 380% or more, even more preferably 400% or more, and particularly preferably 450% or more. The upper limit is not particularly limited, but may be, for example, 600% or 500%.

[0152] When the PTFE is modified PTFE, the tensile elongation of the fluororesin molded article of this disclosure is more preferably 250% or more, even more preferably 280% or more, even more preferably 300% or more, even more preferably 350% or more, even more preferably 380% or more, even more preferably 400% or more, and particularly preferably 450% or more. The upper limit is not particularly limited, but may be, for example, 600% or 500%.

[0153] The fluororesin molded articles of this disclosure preferably have a tensile strength of 14 MPa or more, more preferably 17 MPa or more, even more preferably 20 MPa or more, even more preferably 25 MPa or more, even more preferably 30 MPa or more, and particularly preferably 35 MPa or more. The upper limit is not particularly limited, but may be, for example, 60 MPa or 50 MPa.

[0154] The fluororesin molded article (2) of this disclosure preferably has an orientation degree of 56% or less, preferably 47% or less, more preferably 35% or less, even more preferably 25% or less, even more preferably 15% or less, and particularly preferably 5% or less. The lower limit is not particularly limited, but may be, for example, 0%.

[0155] When the PTFE is modified PTFE, the tensile strength of the fluororesin molded article of this disclosure is preferably 17 MPa or more, more preferably 20 MPa or more, even more preferably 25 MPa or more, even more preferably 30 MPa or more, and particularly preferably 35 MPa or more. The upper limit is not particularly limited, but may be, for example, 60 MPa or 50 MPa.

[0156] The fluororesin molded articles of this disclosure may also preferably contain fillers. Examples of fillers include those that can be used in the manufacturing methods of this disclosure. The fillers are preferably conductive fillers or thermally conductive fillers in that they can provide excellent electrical or thermal conductivity.

[0157] The fluororesin molded articles of this disclosure may also preferably be substantially free of fillers. Substantially free of fillers means that the filler content is less than 0.01% by mass, preferably less than 0.001% by mass, relative to the total amount of the fluororesin and fillers. The lower limit is not limited and may be 0% by mass.

[0158] The fluororesin molded articles of this disclosure can be suitably manufactured, for example, by the manufacturing method of this disclosure described above.

[0159] The fluororesin molded articles obtained by the manufacturing method of the present disclosure, and the fluororesin molded articles of the present disclosure, can be suitably used in lining sheets, packings, gaskets, diaphragm valves, heat-resistant wires, heat-resistant insulating tapes for vehicle motors and generators, release sheets, sealing materials, casings, sleeves, bellows, hoses, piston rings, butterfly valves, rectangular tanks, wafer carriers, circuit boards, nuts, bolts, fittings, semiconductor components, optical lens components, solar cell panel films, OA rolls, and the like. In particular, it can be suitably used for packing, gaskets, sealing materials, casings, and piston rings.

[0160] 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. [Examples]

[0161] The present disclosure will now be further described with reference to examples, but the present disclosure is not limited to these examples.

[0162] Each value was determined using the following method.

[0163] <Melting point> The melting point was defined as the temperature corresponding to the minimum point in the heat of fusion curve obtained when the temperature was increased at a rate of 10°C / min using a differential scanning calorimeter (DSC). If there were two or more minimum points in a single melting peak, each was defined as a melting point.

[0164] <Standard specific gravity (SSG)> Samples were prepared according to ASTM D 4895-89 and measured using the water displacement method according to ASTM D-792.

[0165] <Melting viscosity> The viscosity was quantified using a melt viscoelasticity analyzer MCR302 (manufactured by Anton Paar Japan Co., Ltd.). A 7mm diameter parallel plate was used as the measuring fixture, and the complex viscosity measured at a deformation rate of 0.3%, a sample thickness of 0.5mm, a temperature of 230°C or 380°C, and a frequency of 0.01 radians per second was defined as the melt viscosity. Fluororesins that melt at 230°C were measured at 230°C, and fluororesins that do not melt at 230°C were measured at 380°C.

[0166] <Melt Flow Rate (MFR)> In accordance with ASTM D1238, the MFR (Mass Flow Rate) was defined as the mass of polymer (g / 10 min) flowing out of a nozzle with an inner diameter of 2.095 mm and a length of 8 mm per 10 minutes, using a melt indexer at a measurement temperature of 372°C and a load of 5 kg.

[0167] <Flow Value> Measurements were taken using an elevated flow tester under the following conditions: measurement temperature 230°C, load 980N, and nozzle diameter 1mmφ.

[0168] <Tensile strength and elongation> Measurements were taken in accordance with ASTM D1708.

[0169] <density> Measurements were taken using the liquid weighing method in accordance with JIS Z 8807.

[0170] <Orientation degree> The fluororesin molded articles obtained in Examples 2 and 7 and Comparative Examples 2 and 3 were observed using small-angle X-ray diffusion (SAXS) or ultra-small-angle X-ray diffusion (USAXS). High-resolution SAXS or USAXS was performed at beamline BL19B2 of SPring-8, Japan Synchrotron Radiation Research Institute (JASRI), with an X-ray wavelength of 0.069 nm, X-ray energy of 18 keV, camera length of 3.04 m, and a two-dimensional pixel detector (DECTRIS, PILATUS 2M) at room temperature of 25°C. When observing modified PTFE, a camera length of 41 m was used. Fluororesin molded articles with a thickness of 1-2 mm were used as observation samples without further processing. Molded articles with a thickness of 1 cm or more were processed into a film approximately 0.3 mm thick by cutting and then used for observation. Similarly, the fluororesin molded article obtained in Example 7 was also processed into a film approximately 0.3 mm thick by cutting and used for observation. X-rays were irradiated in the thickness direction (through) and observed. The X-ray exposure time was 60 seconds. The small-angle X-ray diffraction pattern was read using image analysis software (DECTRIS, ALUBLA) to obtain the annular intensity distribution. The degree of orientation was calculated using this annular intensity distribution according to the following formula. The results are shown in Table 3.

number

[0171] The following materials were used in each experimental example. <Fluororesin> PTFE(1):TFE homopolymer (melting point: 345°C, SSG: 2.15, melt viscosity: 10) 12 Pa·s) is compressed, molded, fired, and then crushed. PTFE(2): Modified PTFE (Modified monomer (PPVE) content: 0.15 mass%, Melting point: 339°C, SSG: 2.15, Melt viscosity: 10 11 Pa·s) is compressed, molded, fired, and then crushed. PTFE(3): Uncalcined TFE homopolymer (melting point: 345°C, SSG: 2.15, melt viscosity: 10) 12 Pa·s) powder. PTFE(4): Uncalcined modified PTFE (modified monomer (PPVE) content: 1% by mass, melting point: 339°C, SSG: 2.15, melt viscosity: 10) 11 Pa·s) powder. PTFE(5):TFE polymer (melting point: 345°C, SSG: 2.12, melt viscosity: 10) 12 A mixture of 90% by mass of Pa·s and 10% by mass of carbon fiber is compressed, fired, and then pulverized. PFA:TFE / PPVE copolymer (Melting point: 304℃, MFR: 7.0g / 10min, Melt viscosity: 10%) 4 Pa·s) powder. FEP:TFE / HFP copolymer (Melting point: 270°C, MFR: 3.2g / 10min, Melt viscosity: 10%) 7 Pa·s) powder. PCTFE(1): CTFE homopolymer (melting point: 212°C, flow value: 0.7 × 10⁻⁶) -3 cc / s, melt viscosity: 10 7 Pa·s) powder. PCTFE(2):CTFE homopolymer (melting point: 212°C, flow value: 0.7 × 10⁻⁶) -3 cc / s, melt viscosity: 10 7 Pellets from Pa·s.

[0172] Example 1 PTFE(1) particles were filled into a special mold having an aluminum metal mold, a heating element containing silicon carbide as an electromagnetic wave absorber, and an insulating element arranged around them. The pressure was reduced (-80kPa) in a vacuum line, and microwave irradiation was performed in an AmolsysM300 electromagnetic wave irradiation device manufactured by micro-AMS Co., Ltd. The temperature was raised under conditions of a maximum temperature of 340°C and a holding time of 300 seconds, followed by a cooling process to perform molding and obtain a flat fluororesin molded body measuring 100 × 100 × 1 mmt. The physical properties of the obtained fluororesin molded articles were measured using the method described above. The results are shown in Table 1.

[0173] Example 2 A fluororesin molded article was obtained in the same manner as in Example 1, except that PTFE(2) was used instead of PTFE(1), and its physical properties were measured. The results are shown in Table 1.

[0174] Comparative Example 1 PTFE(1) particles were molded using a compression molding method to obtain a flat fluororesin molded body with a diameter of φ120 × 1 mmt. The physical properties of the obtained fluororesin molded articles were measured using the method described above. The results are shown in Table 1.

[0175] Comparative Example 2 A fluororesin molded article was obtained in the same manner as in Comparative Example 1, except that PTFE(2) was used instead of PTFE(1), and its physical properties were measured. The results are shown in Table 1.

[0176] Examples 3 and 4 A fluororesin molded article was obtained in the same manner as in Example 1, except that a fluororesin shown in Table 2 was used instead of PTFE(1), and its physical properties were measured. The results are shown in Table 2.

[0177] Example 5 A fluororesin molded article was obtained in the same manner as in Example 1, except that PFA was used instead of PTFE(1) and the molding conditions were changed to a maximum temperature of 330°C and a holding time of 180 seconds. The physical properties were then measured. The results are shown in Table 2.

[0178] Example 6 A fluororesin molded article was obtained in the same manner as in Example 1, except that FEP was used instead of PTFE(1) and the molding conditions were changed to a maximum temperature of 280°C and a holding time of 180 seconds. The physical properties were then measured. The results are shown in Table 2.

[0179] Examples 7 and 8 A fluororesin molded article was obtained in the same manner as in Example 1, except that a fluororesin shown in Table 2 was used instead of PTFE(1), and the molding conditions were changed to a maximum temperature of 260°C and a holding time of 300 seconds. The physical properties were then measured. The results are shown in Table 2.

[0180] Example 9 A fluororesin molded article was obtained in the same manner as in Example 1, except that PTFE(5) was used instead of PTFE(1) and the molding conditions were changed to a maximum temperature of 370°C and a holding time of 300 seconds. The physical properties were then measured. The results are shown in Table 2.

[0181] Comparative Example 3 Using a compression molding method, PCTFE(1) particles were molded to obtain a fluororesin molded body with a thickness of 2 cm. This body was then machined in the thickness direction to obtain a flat fluororesin molded body with a thickness of 0.3 mm.

[0182] [Table 1]

[0183] [Table 2]

[0184] [Table 3] [Explanation of symbols]

[0185] 10: Cavity 11: 1st mold part 12:Second mold part 15: Interior space 21, 22: Heating element 31, 32, 33, 34: Insulation

Claims

1. A method for manufacturing a fluororesin molded article, comprising the step of obtaining a fluororesin molded article by molding a molding material containing fluororesin with an electromagnetic wave irradiation molding apparatus.

2. The electromagnetic wave irradiation molding apparatus is equipped with a special mold capable of molding at a temperature of 250°C or higher, and the special mold comprises a metal mold into which the molding material is fed and a heating element, as described in claim 1.

3. The manufacturing method according to claim 2, wherein the metal mold has durability against fluororesin.

4. The manufacturing method according to claim 2 or 3, wherein the heat-generating portion includes an electromagnetic wave absorber.

5. The manufacturing method according to claim 2 or 3, wherein the special mold further comprises an insulating portion around the metal mold and the heating portion.

6. The manufacturing method according to claim 2 or 3, wherein the special mold is heated under reduced pressure conditions to form the molding material.

7. The manufacturing method according to claim 1 or 2, wherein the electromagnetic wave is a microwave.

8. The melt viscosity of the fluororesin is 10 ４ ~10 １４ The manufacturing method according to claim 1 or 2, wherein the material is Pa·s.

9. The manufacturing method according to claim 1 or 2, wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, polychlorotrifluoroethylene, and ethylene / chlorotrifluoroethylene copolymer.

10. The manufacturing method according to claim 1 or 2, wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, and polychlorotrifluoroethylene.

11. The manufacturing method according to claim 1 or 2, wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene and polychlorotrifluoroethylene.

12. The manufacturing method according to claim 1 or 2, wherein the fluororesin is polytetrafluoroethylene.

13. The method for producing the fluororesin according to claim 1 or 2, wherein the fluororesin is polytetrafluoroethylene that has been heated to a temperature above its melting point.

14. The method for producing the fluororesin according to claim 1 or 2, wherein the fluororesin is modified polytetrafluoroethylene that has been heated to a temperature above its melting point.

15. The manufacturing method according to claim 1 or 2, wherein the molding material further comprises an inorganic filler.

16. The manufacturing method according to claim 1 or 2, wherein the molding material is a powder.

17. The manufacturing method according to claim 1 or 2, wherein the density of the fluororesin molded article is 2.10 to 2.20 g / ml.

18. The manufacturing method according to claim 1 or 2, wherein the density of the fluororesin molded article is 2.14 g / ml or more.

19. The manufacturing method according to claim 1 or 2, wherein the fluororesin molded body contains a filler.

20. A fluororesin molded article obtained by the manufacturing method described in claim 1.

21. A fluororesin molded article obtained from a material containing fluororesin, having an orientation degree of 56% or less.

22. The fluororesin molded article according to claim 21, wherein the fluororesin is polytetrafluoroethylene that has been heated to a temperature above its melting point.

23. A fluororesin molded article obtained from a material containing polytetrafluoroethylene that has been heated to a temperature above its melting point, having a density of 2.14 g / ml or more and a tensile elongation of 200% or more.

24. A fluororesin molded article according to claim 23, wherein the density is 2.16 to 2.20 g / ml and the tensile elongation is 200 to 500%.

25. The fluororesin molded article according to claim 23, wherein the polytetrafluoroethylene is modified polytetrafluoroethylene and has a tensile elongation of 400% or more.

26. A fluororesin molded article according to claim 25, wherein the density is 2.16 to 2.20 g / ml and the tensile elongation is 400 to 500%.

27. A fluororesin molded article according to claim 21 or 23, wherein the degree of orientation is 47% or less.

28. A fluororesin molded article according to claim 21 or 23, wherein the degree of orientation is 5% or less.

29. The fluororesin molded article according to claim 21 or 23, wherein the material is a powder.

30. Furthermore, the fluororesin molded article according to claim 21 or 23, further comprising a filler.

31. A fluororesin molded article according to any one of claims 20, 21, and 23, used in at least one selected from the group consisting of lining sheets, packings, gaskets, diaphragm valves, heat-resistant wires, heat-resistant insulating tapes, release sheets, sealing materials, casings, sleeves, bellows, hoses, piston rings, butterfly valves, rectangular tanks, wafer carriers, circuit boards, nuts, bolts, fittings, semiconductor components, optical lens components, solar cell panel films, and OA rolls.

Images