Method for producing surface-modified tetrafluoroethylene-based polymer, method for producing modified powder, liquid composition, method for producing modified molded article, and modified molded article

Abstract

The present invention provides a modified tetrafluoroethylene-based polymer and a method for producing a powder of the polymer, which are modified by plasma treatment under an atmosphere close to atmospheric pressure, and a method for producing a molded article of a tetrafluoroethylene-based polymer, which is highly surface-modified by plasma treatment under an atmosphere close to atmospheric pressure. The method for producing a modified tetrafluoroethylene-based polymer and a powder of the polymer is a method for producing a surface-modified tetrafluoroethylene-based polymer by plasma treatment of a tetrafluoroethylene-based polymer and a powder of the polymer under an atmosphere close to atmospheric pressure. The method for producing a molded article is a method for producing a molded article having a surface layer containing a tetrafluoroethylene-based polymer, by plasma treatment of at least a part of the surface layer of the molded article under an atmosphere close to atmospheric pressure, which contains a reducing gas having a hydrogen atom, so that at least a part of the surface has a modified layer formed by introducing a hydrogen atom into the tetrafluoroethylene-based polymer.

Description

Technical Field

[0001] This invention relates to a method for manufacturing surface-modified tetrafluoroethylene polymers, a method for manufacturing modified powders, a liquid composition, a method for manufacturing modified molded articles, and modified molded articles. Background Technology

[0002] Polymers of tetrafluoroethylene have excellent physical properties such as mold release, electrical insulation, water and oil repellency, chemical resistance, weather resistance, and heat resistance. Liquid compositions in which their powders are dispersed can be used as materials that can be easily formed into various molded objects (Patent Document 1).

[0003] However, tetrafluoroethylene polymers have extremely low polarity and poor interaction with other compounds, such as liquid dispersion media, resulting in insufficient powder dispersibility. Therefore, to improve powder dispersibility and adjust the liquid properties of liquid compositions, surfactants, thickeners, and other modifiers are often added to the liquid composition.

[0004] Furthermore, films made from tetrafluoroethylene polymers exhibit excellent electrical insulation, water and oil repellency, chemical resistance, and heat resistance, making them useful as printing substrate materials (Patent Document 2). However, the adhesiveness of tetrafluoroethylene polymer films remains insufficient. Therefore, to improve surface properties such as adhesiveness, surface modification of the films has been studied. Patent Document 3 describes a method for introducing peroxide functional groups onto the surface of a polytetrafluoroethylene film by plasma treatment in an atmosphere containing rare gases at near atmospheric pressure.

[0005] Furthermore, tetrafluoroethylene polymers are low-polarity polymers with excellent insulation resistance and insulation breakdown properties, and the surface of their molded products is not easily modified. Moreover, the behavior of tetrafluoroethylene polymers when subjected to plasma treatment is not fully understood, and their effects are difficult to stabilize and sometimes difficult to sustain.

[0006] Therefore, the current practice is to combine other methods with plasma treatment of polytetrafluoroethylene polymer molded products. For example, in Patent Document 3, a polytetrafluoroethylene membrane is subjected to plasma treatment to introduce peroxide functional groups on the surface, then immersed in water to introduce hydroxyl groups on the surface, and further subjected to the action of a silane coupling agent to modify the membrane surface.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Text of International Publication No. 2016 / 159102

[0010] Patent Document 2: Text of International Publication No. 2019 / 142790

[0011] Patent Document 3: Japanese Patent Application Publication No. 2013-049819 Summary of the Invention

[0012] The technical problem that the invention aims to solve

[0013] The inventors have investigated a method for plasma treatment that highly modifies the surface of tetrafluoroethylene-based polymer powders.

[0014] The results showed that if the surface of the tetrafluoroethylene polymer powder was treated under specified plasma treatment conditions, the surface was modified, and the surface properties such as wettability of the powder and the dispersibility of the liquid composition prepared therefrom were improved without impairing its physical properties.

[0015] Furthermore, during plasma treatment of molded tetrafluoroethylene polymers, the inventors investigated plasma treatment conditions that could highly modify the surface of the molded tetrafluoroethylene polymers without requiring the combination described in Patent Document 3. The results showed that if the molded article was treated under the specified plasma treatment conditions, a stable layer could be formed. It was also found that by forming this layer, the wettability and surface properties such as adhesion of the molded article were improved without impairing the overall properties of the tetrafluoroethylene polymer.

[0016] The purpose of this invention is to provide a method for highly modifying tetrafluoroethylene polymers to improve their physical properties.

[0017] The object of the present invention is to provide a method for highly surface-modifying powders of tetrafluoroethylene polymers to improve their surface properties, and a liquid composition with excellent dispersibility and other liquid properties prepared thereby.

[0018] The present invention aims to provide a method for highly surface-modifying molded articles of tetrafluoroethylene polymers to improve their surface properties, and molded articles of highly surface-modified tetrafluoroethylene polymers.

[0019] Technical solutions adopted to solve technical problems

[0020] The present invention has the following technical content.

[0021] <1> A method for manufacturing modified tetrafluoroethylene polymers involves plasma treatment of the tetrafluoroethylene polymers under an atmosphere close to atmospheric pressure to obtain surface-modified tetrafluoroethylene polymers.

[0022] <2> A method for manufacturing modified powder involves plasma treatment of tetrafluoroethylene polymer powder under an atmosphere close to atmospheric pressure to modify the surface of the powder.

[0023] <3> As mentioned above <2> The manufacturing method involves subjecting the powder to plasma treatment in an atmosphere containing a reducing gas with hydrogen atoms at near atmospheric pressure to obtain a powder formed by introducing hydrogen atoms into the tetrafluoroethylene polymer.

[0024] <4> As mentioned above <2> or <3> The manufacturing method wherein the plasma treatment is performed in an atmosphere shielded from air.

[0025] <5> As mentioned above <2> ~ <4> The manufacturing method wherein, prior to the plasma treatment, the powder is subjected to plasma treatment in an atmosphere containing rare gases.

[0026] <6> As mentioned above <2> ~ <5> The manufacturing method wherein the atmosphere comprises at least one gas selected from a reducing gas having hydrogen atoms, a vinyl compound, and a vinylidene compound.

[0027] <7> As mentioned above <2> ~ <6> In the manufacturing method described above, the atmosphere further comprises a rare gas.

[0028] <8> As mentioned above <2> ~ <7> In the manufacturing method described above, the pressure close to atmospheric pressure is 0.08 to 0.12 MPa.

[0029] <9> As mentioned above <2> ~ <8> In the manufacturing method described above, the average particle size of the powder is less than 50 μm.

[0030] <10> As mentioned above <2> ~ <9> In the manufacturing method described above, the tetrafluoroethylene polymer is a tetrafluoroethylene polymer with a fluorine content of 70-76% by mass.

[0031] <11> As mentioned above <2> ~ <10> The manufacturing method wherein the tetrafluoroethylene polymer has atomic groups containing oxygen atoms.

[0032] 12. A liquid composition comprising the above-mentioned components. <2> ~ <11> The modified powder and liquid dispersion medium obtained by the manufacturing method, wherein the modified powder is dispersed.

[0033] <13> As mentioned above <12> The liquid composition wherein the average particle size of the modified powder is less than 50 μm.

[0034] <14> As mentioned above <12> or <13> The liquid composition wherein the tetrafluoroethylene polymer is a tetrafluoroethylene polymer with a fluorine content of 70-76% by mass.

[0035] <15> As mentioned above <12> ~ <14> The liquid composition wherein the tetrafluoroethylene polymer has atomic groups containing oxygen atoms.

[0036] <16> A method for manufacturing a molded article, comprising plasma treatment of at least a portion of the surface layer of a molded article having a surface layer comprising a tetrafluoroethylene-based polymer in an atmosphere containing a reducing gas having hydrogen atoms at near atmospheric pressure, such that at least a portion of the surface has a modified layer formed by introducing hydrogen atoms into the tetrafluoroethylene-based polymer.

[0037] <17> As mentioned above <16> The manufacturing method wherein the plasma treatment is performed in an atmosphere shielded from air.

[0038] <18> As mentioned above <16> or <17> In the manufacturing method described above, the surface layer is pre-treated with plasma in an atmosphere free of reducing gases before the plasma treatment.

[0039] <19> As mentioned above <16> ~ <18> In the manufacturing method described above, the reducing gas is hydrogen, ammonia, or a hydrocarbon gas.

[0040] <20> As mentioned above <16> ~ <19> In the manufacturing method described above, the atmosphere of the plasma treatment further includes nitrogen or a rare gas.

[0041] <21> As mentioned above <16> ~ <20> In the manufacturing method described above, the pressure close to atmospheric pressure is 0.08 to 0.12 MPa.

[0042] <22> As mentioned above <16> ~ <21> In the manufacturing method described above, the at least part of the shaped article having a surface layer containing a tetrafluoroethylene polymer is a film of a tetrafluoroethylene polymer, or a laminate having a substrate layer and a layer of a tetrafluoroethylene polymer.

[0043] <23> As mentioned above <16> ~ <22> In the manufacturing method described above, the fluorine content of the tetrafluoroethylene polymer is 70-76% by mass.

[0044] <24> As mentioned above <16> ~ <23> The manufacturing method wherein the tetrafluoroethylene polymer has atomic groups containing oxygen atoms.

[0045] <25> A molded article comprising a tetrafluoroethylene-based polymer, wherein at least a portion of its surface has a modified layer formed by introducing hydrogen atoms into the tetrafluoroethylene-based polymer, wherein the maximum height of the peak located at 284 eV to 286 eV in a region from the surface to a depth of 1 nm, as determined by X-ray photoelectron spectroscopy, is more than 0.2 times the maximum height of the peak located at 289 eV to 295 eV in the same region, and the fluorine atom content in the region is less than 55%.

[0046] <26> As mentioned above <25> The molded article wherein the fluorine content of the tetrafluoroethylene polymer is 70-76% by mass.

[0047] <27> As mentioned above <25> or <26> The molded article wherein the tetrafluoroethylene polymer has atomic groups containing oxygen atoms.

[0048] <28> As mentioned above <25> ~ <27> The shaped article wherein the thickness of the modified layer is less than 1000 nm.

[0049] <29> As mentioned above <25> ~ <27> The molded article is a film of a tetrafluoroethylene polymer or a laminate having a substrate layer and a tetrafluoroethylene polymer layer.

[0050] Invention Effects

[0051] According to the present invention, highly modified tetrafluoroethylene-based polymers can be manufactured.

[0052] According to the present invention, modified powders of tetrafluoroethylene polymers with excellent wetting and dispersibility can be manufactured without impairing the physical properties of tetrafluoroethylene polymers, thereby enabling the easy manufacture of liquid compositions with excellent liquid properties. From these liquid compositions, molded articles (layered articles, single films, etc.) possessing the physical properties of tetrafluoroethylene polymers and exhibiting excellent adhesion can be easily manufactured.

[0053] According to the present invention, it is possible to manufacture molded articles of tetrafluoroethylene polymers in which at least a portion of the surface has a stable modified layer formed by efficiently introducing hydrogen atoms into the tetrafluoroethylene polymer. Furthermore, molded articles of tetrafluoroethylene polymers with improved overall tetrafluoroethylene polymer properties and enhanced surface properties such as adhesion can be obtained. Detailed Implementation

[0054] The following terms have the following meanings.

[0055] "Tetrafluoroethylene polymers" are polymers containing units based on tetrafluoroethylene (hereinafter also referred to as "TFE units").

[0056] The glass transition temperature (Tg) of a polymer is a value determined by analyzing polymers using the dynamic viscoelasticity assay (DMA).

[0057] "The melting temperature (melting point) of a polymer" refers to the temperature corresponding to the maximum value of the melting peak as determined by differential scanning calorimetry (DSC).

[0058] "(Meth)acrylate" refers to the general term for acrylates and methacrylates.

[0059] "D50" is the average particle size of the powder, which is the cumulative 50% diameter of the powder volume as determined by laser diffraction scattering. That is, the particle size distribution of the powder is determined by laser diffraction scattering, and a cumulative curve is obtained with the total volume of the powder as 100%. The particle size at the point on the cumulative curve where the cumulative volume reaches 50% is the average particle size.

[0060] "D90" is the cumulative volumetric particle size of the powder, which is the cumulative 90% diameter of the powder based on the volumetric reference, calculated in the same way.

[0061] "Monomer-based unit" refers to a group of atoms based on the aforementioned monomer, formed through monomer polymerization. The unit can be formed directly through the polymerization reaction, or it can be formed by processing the polymer to transform a portion of the aforementioned unit into a unit with a different structure. Hereinafter, units based on monomer 'a' will also be simply referred to as "monomer 'a' unit".

[0062] The manufacturing method of the present invention (hereinafter also referred to as "this method") is a method for manufacturing modified F polymers by plasma treatment of tetrafluoroethylene polymers (hereinafter also referred to as F polymers) under an atmosphere close to atmospheric pressure.

[0063] The first aspect of this method (hereinafter also referred to as Method 1) is a method for manufacturing a modified powder by subjecting the original powder to plasma treatment at near atmospheric pressure to modify the surface of the powder, using polymer F as the powder (hereinafter also referred to as the original powder).

[0064] The modified powder preferably has a modified layer formed by modifying the F polymer on its surface. More preferably, the modified layer is formed by introducing hydrogen atoms into the F polymer, or by introducing a vinyl compound or vinylidene compound into the F polymer.

[0065] In the modified layer formed by introducing hydrogen atoms into polymer F, the maximum height of the peak located at 284 eV to 286 eV (hereinafter referred to as "peak H") in the region from the surface to a depth of 1 nm, as determined by X-ray photoelectron spectroscopy (hereinafter also referred to as "ESCA"), is preferably 0.2 times or more than 1 times the maximum height of the peak located at 289 eV to 295 eV (hereinafter also referred to as "peak F") in the same region.

[0066] In the surface measurements based on ESCA, a Quantera II (manufactured by ULVAC-PHI Co., Ltd.) was used. Monochromatic AlKα rays at 100W were used as the X-ray source. An ion gun and a neutralization gun with a barium oxide emitter were used to prevent the sample surface from becoming charged. The photoelectron detection area was set to 100 μmφ, the photoelectron detection angle to 45 degrees, and the pass energy to 55 eV. Furthermore, the proportion of fluorine atoms was calculated based on the various peak intensities (N1s, O1s, C1s, and F1s orbitals) detected by the measurements. Additionally, the depth from the surface was determined based on the sputtering rate of the SiO2 sputtered film using C60 ions as sputtering ions.

[0067] Peaks H and F are photoelectron peaks based on the 1s orbital of carbon atoms (C1s) and the 1s orbital of fluorine atoms (F1s), respectively. In other words, peak H can be regarded as a peak originating from a single bond (CH bond) between carbon and hydrogen atoms, and peak F can be regarded as a peak originating from a single bond (CF bond) between carbon and fluorine atoms.

[0068] In addition to peaks H and F, the above region may also contain photoelectron peaks based on the 1s orbital of oxygen atoms (O1s) and photoelectron peaks based on the 1s orbital of nitrogen atoms (N1s) (hereinafter also referred to as "other peaks").

[0069] The proportion of fluorine atoms in the above-mentioned region [atomic percentage] is preferably 55% or less, more preferably 40% or less.

[0070] The percentage of fluorine atoms is calculated using the following steps.

[0071] Within the range of photoelectron peaks of C1s, O1s, N1s, and F1s in ESCA, the background is subtracted to calculate the peak intensity of each element (carbon, oxygen, nitrogen, and fluorine).

[0072] For each of the four elements, the peak intensity is calculated by dividing the peak intensity by the relative sensitivity coefficient specific to that element. The proportion of the peak intensity (correction value) of fluorine atoms in the total correction value is taken as the "fluorine atom content ratio".

[0073] In addition, on the surface of the original powder, the maximum height of peak H is preferably less than 0.2 times, more preferably less than 0.1 times, relative to the maximum height of peak F.

[0074] Furthermore, the proportion of fluorine atoms in the surface of the original powder is preferably greater than 55%, more preferably greater than 60%.

[0075] According to Method 1, modified powders with improved surface properties (wetting properties, etc.) and dispersion stability can be obtained without impairing the overall physical properties (electrophysical properties, etc.) of the F polymer. The mechanism of action is not necessarily clear, but it is believed to be as follows.

[0076] The plasma treatment in Method 1 is carried out at near atmospheric pressure, in other words, in an atmosphere with high gas density. Therefore, it is believed that the gases contained in the atmosphere undergo partial plasmaification. Furthermore, it is believed that the gases contained in the atmosphere not only transform into plasma themselves, but also form electrically neutral free radicals, which become modifying components of the polymer.

[0077] That is, it is believed that in the plasma treatment in Method 1, since the plasma treatment is carried out in this state, the F polymer can be easily and effectively modified.

[0078] For example, if the gas contains a reducing gas with hydrogen atoms, it is considered that not only does it itself become plasma, but it also becomes electrically neutral hydrogen radicals. As a result, it is believed that the hydrogen radicals act on the CF bonds of the plasma-activated F polymer, thus modifying the polymer. In particular, since the atomic radius of hydrogen atoms is comparable to that of fluorine atoms, this interaction is considered to be easily enhanced.

[0079] As a result, according to Method 1, it is believed that non-fluorine atoms or molecules can be effectively introduced into the F polymer contained on the surface of the original powder. In addition, the cleavage of the F polymer on the surface of the original powder caused by plasma is suppressed, and its molecular weight reduction is also suppressed, so the surface state of the modified F polymer is easily stabilized.

[0080] Based on this mechanism, it is believed that by using this method 1, a powder with the physical properties of F polymer and excellent surface properties can be obtained, thereby making it easy to prepare a liquid composition with excellent dispersibility.

[0081] The fluorine content of the F polymer is preferably 70-76% by mass. In this high-fluorine-content F polymer, the physical properties (electrophysical properties, etc.) are excellent; however, the polarity is particularly low, resulting in poor surface properties (wetting properties, etc.) of the original powder. According to this method, even in this original powder, a modified powder with improved surface properties can be obtained without compromising the overall physical properties of the F polymer.

[0082] The melting temperature of polymer F is preferably above 180°C, more preferably 200–325°C, and even more preferably 280–320°C. The glass transition temperature of polymer F is preferably 30–150°C, more preferably 75–125°C. Polytetrafluoroethylene (PTFE), polymers containing TFE units and perfluoro(alkyl vinyl ether) (PAVE)-based units (PAVE units) (PFA), or copolymers containing TFE and hexafluoropropylene-based units (FEP) are preferred, with PFA or FEP being particularly preferred. These polymers may also contain units based on other comonomers.

[0083] As a PAVE, CF2 = CFOCF3, CF2 = CFOCF2CF3 or CF2 = CFOCF2CF2CF3 (PPVE) is preferred, and PPVE is more preferred.

[0084] The F polymer preferably has atomic groups containing oxygen atoms. According to this method, modified molded articles with further improved surface properties can be easily obtained without impairing the physical properties of the F polymer based on these atomic groups.

[0085] The aforementioned atomic groups can be contained in the monomer units of the F polymer or in the terminal groups of the polymer backbone. As an example of the latter, polymers having the aforementioned atomic groups as terminal groups derived from polymerization initiators, chain transfer agents, etc., can be cited.

[0086] The atomic group containing oxygen atoms is preferably a hydroxyl group or a carbonyl group, and particularly preferably a carbonyl group.

[0087] The hydroxyl group is preferably a group containing an alcohol hydroxyl group, more preferably -CF2CH2OH or -C(CF3)2OH.

[0088] The carbonyl group is a group containing a carbonyl group (>C(O)), preferably a carboxyl group, alkoxy carbonyl group, amide group, isocyanate group, urethane group (-OC(O)NH2), acid anhydride residue (-C(O)OC(O)-), imide residue (-C(O)NHC(O)-, etc.) or carbonate group (-OC(O)O-), with acid anhydride residues being particularly preferred.

[0089] When polymer F contains carbonyl groups, the number of carbonyl groups in polymer F relative to 1 × 10 6 The number of carbon atoms in the main chain is preferably 10 to 5000, more preferably 100 to 3000, and even more preferably 800 to 1500. Furthermore, the number of carbonyl groups in the F polymer can be quantified according to the method described in International Publication No. 2020 / 145133.

[0090] Examples of preferred forms of F polymers include polymers containing TFE and PAVE units and having oxygen-containing groups (1), or polymers containing TFE and PAVE units, containing PAVE units at a rate of 2.0 to 5.0 mol% relative to all monomer units, and not having oxygen-containing groups (2). These polymers form microspheres in the molded article, thus facilitating the formation of the modified layer according to Method 1.

[0091] Polymer (1) is preferably a polymer comprising TFE units, PAVE units, and monomer units having hydroxyl or carbonyl groups. Polymer (1) preferably comprises 90 to 99 mol% of TFE units, 0.5 to 9.97 mol% of PAVE units, and 0.01 to 3 mol% of units based on the above monomers relative to all units.

[0092] In addition, the monomers mentioned above are preferably itaconic anhydride, citraconic anhydride or 5-norbornene-2,3-dicarboxylic anhydride (also known as nadic anhydride; hereinafter also referred to as "NAH").

[0093] As a specific example of polymer (1), the polymer described in International Publication No. 2018 / 16644 can be cited.

[0094] The polymer (2) consists only of TFE units and PAVE units, preferably containing 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units relative to all units.

[0095] The content of PAVE units in polymer (2) is preferably 2.1 mol% or more, more preferably 2.2 mol% or more, relative to all monomer units.

[0096] In addition, polymer (2) does not have atomic groups containing oxygen atoms, meaning that, relative to the number of carbon atoms constituting the polymer backbone, 1 × 10⁻⁶. 6 The polymer contains fewer than 500 oxygen-containing groups. Preferably, the number of oxygen-containing groups is less than 100, more preferably less than 50. The lower limit for the number of oxygen-containing groups is typically 0.

[0097] The polymer (2) can be manufactured by using a polymerization initiator or chain transfer agent that does not produce oxygen-containing groups as end groups of the polymer chain, or by fluorinating an F polymer having oxygen-containing groups. As a method of fluorination, the use of fluorine gas can be cited (see Japanese Patent Application Publication No. 2019-194314, etc.).

[0098] The raw powder is preferably composed of F polymer. The content of F polymer in the raw powder is preferably 80% by mass or more, more preferably 100% by mass.

[0099] Other components that may be included in the original powder include heat-resistant resins such as aromatic polyesters, polyamide-imides, thermoplastic polyimides, polyphenylene ethers, and polyphenylene oxides. The D50 of the original powder is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 8 μm or less. The D50 of the original powder is preferably 0.1 μm or more, more preferably 0.3 μm or more, and even more preferably 1 μm or more. Furthermore, the D90 of the original powder is preferably less than 100 μm, more preferably 90 μm or less. If the D50 and D90 of the original powder are within the above ranges, its surface area increases, making modification of the original powder easier.

[0100] The plasma treatment in Method 1 is carried out in an atmosphere close to atmospheric pressure. "Close to atmospheric pressure" refers to a pressure of 0.1 ± 0.02 MPa. From the viewpoint of controlling plasma generation in the atmosphere and enhancing the effect of hydrogen reducing species, a pressure of 0.08 to 0.12 MPa is preferred. From the viewpoint of shielding against external gases and suppressing the mixing of components that hinder plasma treatment, a pressure of at least atmospheric pressure (0.101325 MPa) and less than 0.12 MPa is more preferred.

[0101] The plasma treatment in Method 1 is preferably carried out in an atmosphere containing any one of a reducing gas having hydrogen atoms, a vinyl compound, and a vinylidene compound. As the reducing gas having hydrogen atoms, hydrogen, ammonia, or a hydrocarbon gas is preferred; more preferably, hydrogen, ammonia, methane, or ethane; from the viewpoint of being a hydrogen reducing agent in the above-described mechanism, hydrogen or ammonia is more preferred; and hydrogen is most preferred. Two or more reducing gases may be used in combination.

[0102] Vinyl compounds are derived from the formula CH2=CHR 1 The compound represented by (R in the formula) 1 (Representing a monovalent organic group), specific examples include acrylic acid, acrylates, acrylamide, α-olefins (propylene, 1-butene, etc.), vinyl ethers, vinyl esters, allyl ethers, vinyl chloride, and styrene. Vinyl compounds are preferably acrylic acid or acrylates. Two or more vinyl compounds may be used in combination. Vinylene compounds refer to compounds with the formula CH2=CHR. 2 R 3 The compound represented by (R in the formula) 2 and R 3Each of the following (representing a single monovalent organic group) can be used independently: examples include methacrylic acid, methacrylates, methacrylamide, and vinylidene chloride. Vinyl compounds are preferably methacrylic acid or methacrylates. Two or more vinylidene compounds may be used in combination.

[0103] The atmosphere in plasma processing may consist of only any of the gases mentioned above, or it may also contain other gases. From the viewpoint of controlling plasma generation, it is preferable to contain reducing gases and other gases. Other gases are preferably water vapor, nitrogen, or rare gases. From the above viewpoint, rare gases are more preferred, helium, argon, or neon are even more preferred, and argon is the most preferred.

[0104] The concentration of a gas containing a reducing gas having hydrogen atoms or any one of vinyl compounds and vinylidenes in the plasma treatment atmosphere is preferably greater than 99% by volume, more preferably 99.5% by volume or more, and even more preferably 99.9% by volume or more. The upper limit of the concentration of the above-mentioned gas is 100% by volume. When the atmosphere contains the above-mentioned gas and rare gases, it is acceptable as long as the total concentration of the above-mentioned gas and rare gases is within the above-mentioned range.

[0105] If the gas concentration in the atmosphere is within the above range, the above-mentioned mechanism of action is easily enhanced. The above-mentioned atmosphere can be formed by using high-purity gases or by shielding the air from the atmosphere in the plasma treatment described below.

[0106] The gas composition of the above-described atmosphere preferably includes 0.1% by volume or more of a reducing gas, more preferably more than 1% by volume. The gas composition of the above-described atmosphere preferably includes 100% by volume or less of a reducing gas, more preferably less than 50% by volume. Preferred examples of the gas composition of the above-described atmosphere include a gas composition comprising 75–99.5% by volume and 0.5–25% by volume of a rare gas and hydrogen, respectively, and a gas composition comprising 75–99% by volume and 1–25% by volume of a rare gas and ammonia, respectively. Furthermore, these gas compositions preferably do not contain oxygen.

[0107] The plasma treatment in Method 1 is preferably carried out in a gas atmosphere containing a reducing gas having hydrogen atoms, or in a gas atmosphere containing the aforementioned vinyl compound or vinylidene compound. In the former case, a modified powder formed by introducing hydrogen atoms into the surface of the modified powder can be obtained; in the latter case, a modified powder with polyvinyl compound chains or polyvinylidene compound chains introduced into the surface of the modified powder can be obtained.

[0108] Examples of vinyl or vinylidene compounds include acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate, with acrylic acid being preferred. In this case, (meth)acrylic acid chains and (meth)acrylate chains are readily and densely introduced into the surface of the original powder.

[0109] In this case, the concentration (volume basis) of vinyl compounds or vinylidene compounds in the gaseous atmosphere is preferably 1200 to 1400 ppm.

[0110] Furthermore, from the viewpoint of controlling plasma generation, the gas atmosphere in this case preferably also contains other gases. The preferred form of the other gases is the same as the preferred form of other gases in the atmosphere containing a reducing gas having hydrogen atoms described above.

[0111] In addition, when the vinyl or vinylidene compound is in liquid or solid form, it can be heated to be used as a gas or bubbled to produce gas.

[0112] From the viewpoint of suppressing the introduction of components that hinder plasma processing, the plasma processing in Method 1 is preferably carried out in an atmosphere shielded from air (especially oxygen), and more preferably in an atmosphere completely shielded from air.

[0113] Examples of methods for shielding against air include setting the atmospheric pressure in plasma processing above atmospheric pressure and setting up barrier walls in plasma processing equipment to suppress air mixing.

[0114] Examples of plasma treatment methods in Method 1 include: preparing raw powder and performing plasma discharge in a plasma cavity containing a reducing gas or other raw material gas to achieve the required atmosphere; and placing raw powder between opposing electrodes and performing plasma discharge while supplying a raw material gas to achieve the required atmosphere.

[0115] The voltage during plasma discharge is preferably 5–20 kV. The frequency of the power supply during plasma discharge is preferably 50 Hz–100 MHz. The discharge power density relative to the electrode area during plasma discharge is preferably 1–400 W·min / cm². 2 When plasma discharge is performed under the above discharge conditions, the adhesion of the modified molded article tends to become excellent. For the original powder being tested, the discharge time during plasma discharge is preferably 0.1 seconds to 300 minutes.

[0116] The preferred temperature for plasma discharge is 0–300°C, more preferably 10–50°C.

[0117] If plasma discharge is performed under these conditions, it is easier to introduce hydrogen atoms, or either polyvinyl chloride compound chains or polyvinylene compound chains into the F polymer present on the surface of the original powder containing F polymer. This makes it easier to obtain modified powders with highly improved surface properties such as wettability without compromising the overall properties of the F polymer.

[0118] In particular, if the temperature during plasma discharge is within the above range, it is easier to form a more selective and denser modified layer.

[0119] In Method 1, it is preferable to pre-treat the surface of the original powder in an atmosphere containing rare gases before subjecting it to plasma treatment. This pretreatment yields a more highly modified powder. The atmosphere preferably does not contain reducing gases.

[0120] The modified powder obtained by this method 1 has improved surface properties such as wettability and high dispersibility in liquid dispersion media.

[0121] The sedimentation rate of the modified powder is preferably 60% or less, more preferably 50% or less, and even more preferably 40% or less. Here, sedimentation rate refers to the value calculated by the following formula after dispersing the modified powder in a liquid dispersion medium, measuring 1.3 μL of a dispersion containing 5% by mass of the modified powder, adding it to a 1.5 μL microtube (model: 1-7521-01, manufactured by Azwan Co., Ltd.), and centrifuging at 13000 rpm for 5 minutes. If no sedimentation occurs, the sedimentation rate is 0%.

[0122] Sedimentation rate [%] = (Height of sedimented component / Total height of dispersion) × 100

[0123] The liquid dispersion medium can be water or a non-aqueous dispersion medium. As a non-aqueous dispersion medium, a liquid compound selected from amides, ketones and esters is preferred, and N-methyl-2-pyrrolidone, γ-butyrolactone, cyclohexanone or cyclopentanone is more preferred.

[0124] Preferably, the liquid composition comprising the modified powder obtained by method 1 and a liquid composition thereof, wherein the modified powder is dispersed therein (hereinafter also referred to as "the composition") is prepared.

[0125] The content of the modified powder in this composition is preferably 1-60% by mass, more preferably 10-50% by mass. Furthermore, the content of the liquid dispersion medium is preferably 40-99% by mass, more preferably 50-90% by mass. This composition may also contain inorganic fillers or other resins (polymers) different from polymer F. The modified powder exhibits excellent wettability and dispersibility, so in this case, the dispersion stability of the composition is also readily excellent. In particular, even when PTFE is included as another resin, it is easy to prepare a highly dispersible liquid composition. This liquid composition is preferably prepared by mixing the modified powder and an aqueous dispersion containing PTFE powder.

[0126] The viscosity of this composition is preferably 50–1000 mPa·s, more preferably 75–500 mPa·s. Under these conditions, the coating properties of this composition are excellent. The thixotropic ratio of this composition is preferably 1.0–2.2. Under these conditions, the coating properties and homogeneity of this composition are excellent. Furthermore, the thixotropic ratio is calculated by dividing the viscosity of this composition measured at 30 rpm by the viscosity of this composition measured at 60 rpm.

[0127] This composition exhibits excellent dispersion stability and can form molded articles with excellent crack resistance and strong adhesion to the substrate without compromising the physical properties of the F polymer. If this composition is applied to the surface of a substrate and heated to form a polymer layer containing the F polymer (hereinafter also referred to as "F layer (1)"), a laminate having a substrate layer and an F layer can be manufactured.

[0128] In the manufacture of the laminate, it is sufficient to form an F layer (1) on at least one side of the substrate surface. The F layer (1) can be formed on only one side of the substrate or on both sides of the substrate. The surface of the substrate can be surface treated with a silane coupling agent or the like. When coating this composition, coating methods such as spraying, roller coating, spin coating, gravure coating, microgravure coating, gravure offset coating, doctor blade coating, touch coating, bar coating, die coating, spray Mayer wire-wound bar coating, and slot die coating can be used.

[0129] The F layer (1) is preferably formed by heating to remove the dispersion medium and then firing it into a polymer. Particularly preferred is the formation by heating the substrate to the temperature at which the dispersion medium evaporates (100–300°C) and then heating the substrate to the firing temperature range of the polymer (300–400°C). That is, the F layer (1) is preferably a sintered product containing PTFE and PFA. The thickness of the F layer (1) is preferably 0.1 μm or more, more preferably 1 μm or more. The upper limit of the thickness is 100 μm. Within this range, an F layer with excellent crack resistance can be easily formed. The peel strength between the F layer (1) and the substrate layer is preferably 3 N / cm or more, more preferably 10 N / cm or more, and even more preferably 15 N / cm or more. The peel strength is preferably 100 N / cm or less. If this composition is used, the laminate can be easily formed without impairing the properties of the PTFE in the F layer.

[0130] Examples of substrate materials include copper, aluminum, iron, glass, resin, silicon, and ceramics. Examples of substrate shapes include planar, curved, and uneven surfaces, as well as foil, plate, film, and fibrous forms. Specific examples of laminates include metal-clad laminates having a metal foil and an F layer (1) on at least one surface of the metal foil, and multilayer films having a polyimide film and F layers (1) on both surfaces of the polyimide film. These laminates possess excellent electrical properties and other physical properties, making them suitable as printed circuit board materials. Specifically, these laminates can be used in the manufacture of flexible or rigid printed circuit boards.

[0131] If the composition is impregnated in a fabric and dried by heating, an impregnated fabric in which the F polymer is impregnated can be obtained. The impregnated fabric can also be referred to as a coated fabric obtained by coating the fabric with the F layer (1). The fabric is preferably a glass fiber fabric, a carbon fiber fabric, an aramid fiber fabric, or a metal fiber fabric, and more preferably a glass fiber fabric or a carbon fiber fabric. From the viewpoint of improving the tight adhesion between the fabric and the F layer (1), the fabric can be treated with a silane coupling agent. The total content of the F polymer in the fabric is preferably 30 to 80% by mass. Examples of methods for impregnating the composition in the fabric include immersing the fabric in the composition and coating the fabric with the composition.

[0132] The polymer can also be sintered during the drying of the fabric. One method for sintering the polymer is to pass the fabric through a ventilated drying oven at an atmosphere of 300–400°C. Alternatively, the drying of the fabric and the sintering of the polymer can be performed in one step. The impregnated fabric exhibits excellent properties such as high adhesion between the F layer (1) and the fabric, high surface smoothness, and minimal deformation. If this fabric is hot-pressed with a metal foil, a metal-coated laminate with high peel strength and minimal warping can be obtained, making it suitable as a printing substrate material.

[0133] Alternatively, a laminate consisting of a substrate and an impregnated fabric layer can be manufactured by placing a fabric impregnated with the composition onto the surface of a substrate, heating and drying it to form an impregnated fabric layer comprising the F polymer and the fabric. The form is not particularly limited; if a fabric impregnated with the dispersion is coated onto part or all of the inner wall surface of a component such as a tank, pipe, or container, and the component is heated while rotating, an impregnated fabric layer can be formed on part or all of the inner wall surface of the component. This manufacturing method is also useful as a lining method for the inner wall surface of components such as tanks, pipes, and containers.

[0134] According to the above-described mechanism of action, this composition exhibits excellent dispersion stability and can be effectively impregnated in porous or fibrous materials. Examples of such porous or fibrous materials include materials other than the aforementioned woven fabrics, specifically plate-like, columnar, or fibrous materials. These materials can be pretreated with curable resins, silane coupling agents, etc., and may be further filled with inorganic fillers. Furthermore, these materials can be twisted into yarns, cables, or wires. During twisting, an intermediate layer composed of other polymers such as polyethylene can also be incorporated. Examples of manufacturing molded articles by impregnating this composition in such materials include impregnating this composition in a curable resin or a fibrous material carrying the cured material.

[0135] Examples of fibrous materials include high-strength and low-elongation fibers such as carbon fiber, aramid fiber, and silicon carbide fiber. Preferred curing resins are thermosetting resins such as epoxy resin, unsaturated polyester resin, and polyurethane resin. A specific example of this type is a composite cable formed by impregnating this composition into a cable made by twisting carbon fibers loaded with a thermosetting resin, and then heating and firing the F polymer. This composite cable can be used for large structures, ground anchors, oil drilling, cranes, cableways, elevators, agriculture, forestry, fisheries, and slings.

[0136] The second aspect of the manufacturing method of the present invention (hereinafter also referred to as "Method 2") is a method for manufacturing a modified molded article (hereinafter also referred to as the original molded article) having at least a portion of a surface layer containing an F polymer under a near-atmospheric pressure atmosphere containing a reducing gas having hydrogen atoms, thereby causing at least a portion of the surface to have a modified layer formed by introducing hydrogen atoms into the F polymer.

[0137] In Method 2, the maximum height of peak H in the modified layer is preferably more than 0.2 times the maximum height of peak F, and more preferably more than 1 time.

[0138] Peaks H and F are the same as above.

[0139] Furthermore, the proportion of fluorine atoms in the above-mentioned region [atomic percentage] is preferably 55% or less, more preferably 40% or less.

[0140] The proportion and steps for adding fluorine atoms are the same as described above.

[0141] In addition, on the surface of the original formed article, the maximum height of peak H is preferably less than 0.2 times, more preferably less than 0.1 times, relative to the maximum height of peak F.

[0142] Furthermore, the proportion of fluorine atoms in the surface of the original formed article is preferably greater than 55%, more preferably greater than 60%.

[0143] According to Method 2, a modified molded article containing polymer F can be obtained, wherein at least a portion of the surface of the modified layer has excellent surface properties (wetting properties, etc.) without impairing the overall physical properties (electrophysical properties, etc.) of the polymer F. The mechanism of action is not necessarily clear, but is believed to be as follows.

[0144] The plasma treatment in Method 2 is carried out at near atmospheric pressure, in other words, in an atmosphere with high gas density. Therefore, it is believed that the gases contained in the atmosphere undergo partial ionization. Furthermore, it is believed that the reducing gases containing hydrogen atoms in the atmosphere not only transform into plasma themselves, but also into electrically neutral hydrogen radicals.

[0145] That is, it is assumed that the plasma treatment in Method 2 is performed in a state where both plasma and hydrogen free radicals are present. Since the plasma treatment is carried out in this state, it is assumed that the hydrogen free radicals act on the CF bonds of the plasma-activated F polymer to form a modified layer. In particular, since the atomic radius of hydrogen atoms is similar to that of fluorine atoms, it is assumed that this interaction is easily enhanced, effectively forming a modified layer.

[0146] As a result, it is believed that this method 2 efficiently introduces hydrogen atoms into the F polymer contained on the surface of the molded article, forming a modified layer. Furthermore, it is believed that the reduction of the molecular weight of the F polymer caused by plasma is suppressed due to the action of hydrogen free radicals, thus enabling the formation of a highly stable modified layer.

[0147] Based on this mechanism, it is believed that through this method 2, a modified molded article can be obtained, which is a molded article of F polymer with a modified layer formed by introducing hydrogen atoms into the F polymer on the surface of the molded article containing the F polymer, and possessing the overall physical properties of the F polymer and the surface physical properties of the molded article.

[0148] The thickness of the modified layer in the modified molded article is preferably less than 1000 nm, more preferably less than 500 nm, and particularly preferably less than 100 nm. The thickness of the modified layer is preferably more than 1 nm. The thickness of the modified layer refers to its length in the direction perpendicular to its plane when the modified layer has a planar unfolded shape, and its shortest length when the modified layer does not have a planar unfolded shape.

[0149] The definition and scope of polymer F in this Law 2 are as described above.

[0150] In Method 2, the original molded article is a molded article whose surface layer contains F polymer. Furthermore, the surface layer of the molded article refers to the region extending at least approximately 1000 nm from the surface of the molded article in the thickness direction. The molded article to which Method 2 applies is a molded article whose surface layer contains F polymer. The thickness of the molded article is the same as described above, being its length in the direction perpendicular to its plane when the molded article has a planar unfolded shape, and its shortest length when the molded article does not have a planar unfolded shape.

[0151] The original product may contain F polymer entirely or only on the surface. In the latter case, F polymer may be contained in the entire surface or only in a portion of the surface.

[0152] The surface shape of the original material can be smooth or uneven.

[0153] The original molded article is preferably a molded article having a layer containing F polymer on the surface, and more preferably a sheet molded article having a layer portion containing F polymer on the surface.

[0154] The thickness of the layer containing polymer F on the surface is preferably 1 μm or more, more preferably 5 μm or more, and particularly preferably 10 μm or more. The thickness of the layer containing polymer F is preferably 1 mm or less. If the original molded article has a layer containing polymer F on the surface of this thickness, a modified molded article possessing the polymer F properties and surface properties of the molded article as a whole can be easily obtained by this method.

[0155] The original product is preferably a film of F polymer, or a laminate having a substrate layer and a layer containing F polymer (hereinafter also referred to as "F layer (2)") with F layer (2) on the surface. In the film of F polymer, or in the laminate with F layer (2) on both sides, this method can be applied to both sides or only to one side.

[0156] The membrane of F polymer preferably uses F polymer as the main component, and preferably contains more than 50% by mass and less than 100% by mass of F polymer.

[0157] Other components that may be contained in the F polymer membrane include heat-resistant resins such as epoxy resin, maleimide resin, polyurethane resin, polyimide resin, polyamide-imide resin, polyphenylene ether resin, polyphenylene ether resin, and liquid crystal polyester resin; inorganic fillers such as nitride fillers, silica fillers, mica fillers, clay fillers, and talc fillers; carbon fillers such as carbon fiber; and elastomers.

[0158] The substrate layer of the laminate is preferably a resin substrate layer or a metal substrate layer.

[0159] Examples of metal substrate layers include metal foil, and examples of materials include copper, nickel, aluminum, titanium, and their alloys.

[0160] Examples of resin substrates include resin films, and examples of resin materials include polyimide, polyarylate, polysulfone, polyarylsulfone, polyamide, polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamide-imide, liquid crystal polyester, and liquid crystal polyesteramide. Furthermore, examples of resin substrates include prepregs used as precursors for fiber-reinforced resin substrates.

[0161] As preferred forms of laminates, examples include metal-clad laminates having a metal foil and an F layer (2) formed on at least one surface of the metal foil, and multilayer films having a resin film and an F layer (2) formed on at least one surface of the resin film.

[0162] The metal foil in the metal-clad laminate is preferably copper foil. This metal-clad laminate is particularly useful as a printed circuit board material. The resin film of the multilayer film is preferably a polyimide film. This multilayer film can be used as a wire coating material and a printed circuit board material.

[0163] The plasma treatment in Method 2 is carried out in an atmosphere containing a reducing gas with hydrogen atoms.

[0164] As a reducing gas containing hydrogen atoms, hydrogen, ammonia, or a hydrocarbon gas is preferred, more preferably hydrogen, ammonia, methane, or ethane. From the viewpoint of being able to serve as the hydrogen reducing agent in the above-described mechanism of action, hydrogen or ammonia is more preferred, and hydrogen is the most preferred. One reducing gas may be used alone, or two or more may be used in combination.

[0165] The atmosphere in plasma processing may consist only of a reducing gas, or it may contain other gases. From the viewpoint of controlling plasma generation, it is preferable to contain a reducing gas and other gases. The other gases are preferably water vapor, nitrogen, or rare gases. From the above viewpoint, rare gases are more preferred, helium, argon, or neon are even more preferred, and argon is the most preferred.

[0166] The concentration of reducing gas in the atmosphere during plasma processing (in the case where the atmosphere includes the aforementioned gas and rare gas, this refers to the total concentration of the aforementioned gas and rare gas) is preferably greater than 99% by volume, more preferably 99.5% by volume or more, and even more preferably 99.9% by volume or more. The upper limit for the concentration of the aforementioned gas is 100% by volume. If the gas concentration in the atmosphere is within the above range, the aforementioned mechanism of action is easily enhanced. The aforementioned atmosphere can be formed by using high-purity gas or by shielding air from the atmosphere of the plasma processing described below.

[0167] The gas composition of the above-described atmosphere preferably includes 0.1% by volume or more of a reducing gas, more preferably more than 1% by volume. The gas composition of the above-described atmosphere preferably includes 100% by volume or less of a reducing gas, more preferably less than 50% by volume. Preferred examples of the gas composition of the above-described atmosphere include a gas composition comprising 75–99.5% by volume and 0.5–25% by volume of a rare gas and hydrogen, respectively, and a gas composition comprising 75–99% by volume and 1–25% by volume of a rare gas and ammonia, respectively. Furthermore, these gas compositions preferably do not contain oxygen.

[0168] The plasma treatment in Method 2 is carried out in an atmosphere close to atmospheric pressure. "Close to atmospheric pressure" refers to a pressure of 0.1 ± 0.02 MPa. From the viewpoint of controlling plasma generation in the atmosphere and enhancing the effect of hydrogen reducing species, a pressure of 0.08 to 0.12 MPa is preferred. From the viewpoint of shielding against external gases and suppressing the mixing of components that hinder plasma treatment, a pressure of at least atmospheric pressure (0.101325 MPa) and less than 0.12 MPa is more preferred.

[0169] From the viewpoint of suppressing the introduction of components that hinder plasma processing, the plasma processing in Method 2 is preferably carried out in an atmosphere shielded from air, especially oxygen, and more preferably in an atmosphere that is completely shielded from air.

[0170] Examples of methods for shielding against air include setting the atmospheric pressure in plasma processing above atmospheric pressure and setting up barrier walls in plasma processing equipment to suppress air mixing.

[0171] Examples of plasma treatment methods in Method 2 include: placing the original molded object in a plasma cavity containing a raw material gas such as a reducing gas to achieve atmospheric conditions, and placing the original molded object between opposing electrodes and supplying a raw material gas to achieve atmospheric conditions while performing plasma discharge.

[0172] The voltage during plasma discharge is preferably 5–20 kV. The frequency of the power supply during plasma discharge is preferably 50 Hz–100 MHz. The discharge power density relative to the electrode area during plasma discharge is preferably 1–400 W·min / cm². 2 When plasma discharge is performed under the above discharge conditions, the adhesion of the modified molded product tends to become excellent.

[0173] For the original molded object, the discharge time during plasma discharge is preferably 0.1 seconds to 300 minutes.

[0174] The preferred temperature for plasma discharge is 0–300°C, more preferably 10–50°C.

[0175] If plasma discharge is performed under these conditions, it is easier to introduce hydrogen atoms into the F polymer present on the surface of the original molded part containing F polymer, and it is easier to obtain modified molded parts with highly improved surface properties such as wettability without damaging the overall properties of the F polymer.

[0176] In particular, if the temperature during plasma discharge is within the above range, it is easier to form a more selective and denser modified layer.

[0177] In Method 2, the surface of the original molded article can also be pre-treated with plasma in an atmosphere free of reducing gases before plasma treatment. If the surface of the original molded article is moderately roughened by this treatment, the contact area between the plasma and the surface of the molded article increases during the plasma treatment of this method, making it easier to form a modified layer with a higher degree of hydrogen atom induction. The atmosphere preferably contains a rare gas.

[0178] If the original molded article is the aforementioned laminate and is further laminated with other substrates, the bonding strength with other substrates can be improved if this method 2 is applied to the F layer (2) of the original molded article to form a modified layer before lamination. For example, if an original molded article is made by coating a liquid composition containing F polymer powder onto a strip substrate and heating it to form the F layer (2), and this method 2 is applied to its F layer (2), and it is further laminated with other strip substrates by a roll-to-roll process, a strip composite substrate can be easily obtained.

[0179] Furthermore, when the original molded article is a long, cylindrical laminate, a modified molded article with a modified layer can be obtained by unwinding the original molded article from the roll, passing it between opposing electrodes, and simultaneously supplying a raw material gas to achieve the required atmosphere conditions for plasma discharge. The resulting modified molded article can be directly fed into a lamination process for stacking with other substrates, or it can be temporarily wound into a cylindrical shape, unwound, and then fed into the lamination process for stacking with other substrates. From the viewpoint of simplifying the process, it is preferable to assemble the discharge device for performing the plasma discharge into the lamination apparatus, so that the original molded article can be pre-treated with plasma before the lamination process.

[0180] The modified molded article of the present invention (hereinafter also referred to as "this molded article") is a molded article having at least a portion of its surface having a modified layer formed by introducing hydrogen atoms into the F polymer, wherein the modified layer is a layer in which the maximum height of the H peak is more than 0.2 times the maximum height of the F peak and the fluorine atom content in the aforementioned region is less than 55%. This molded article is preferably manufactured by method 2 of the present invention.

[0181] The morphology of the polymer F in this molded article, including the preferred morphology, is the same as that in Method 1. The morphology of the modified layer and the state or shape of the surface in this molded article, including the preferred morphology, are the same as those in Method 2. Examples of preferred forms of this molded article include: a film having a modified layer on at least one surface of the polymer F film; a metal-clad laminate having a metal foil and an F layer (2) formed on at least one surface of the metal foil, and having a modified layer on the surface of the F layer (2); and a multilayer film having a resin film and an F layer (2) formed on at least one surface of the resin film, and having a modified layer on the surface of the F layer. When the F layer is formed on both sides of the metal-clad laminate, or when the F layer (2) is formed on both sides of the multilayer film, the modified layer may be on both surfaces.

[0182] The morphologies of these F polymer films, metal foils, resin films, and F layers (2), including preferred morphologies and those of this method, are as follows. 1 The forms are the same.

[0183] This molded article possesses the overall properties of the F polymer and the surface properties derived from high polarity, making it particularly useful as a wire coating material and a printed circuit board material.

[0184] For example, the dielectric constant of the F polymer film or F layer (2) having the modified layer is preferably 2.0 to 3.5, more preferably 2.0 to 3.0. Furthermore, the dielectric constant is measured using a split dielectric resonator (SPDR) at a frequency of 10 GHz under conditions of 23°C ± 2°C and 50 ± 5% relative humidity. In the case where the molded article is a multilayer film, the dielectric constant of the molded article is preferably 2.0 to 3.5, more preferably 2.0 to 3.0. The water contact angle of the outermost layer (modified layer) of the molded article is preferably 100° or less, more preferably 90° or less. Furthermore, the water contact angle of the outermost layer (modified layer) of the molded article is preferably 10° or more, more preferably 30° or more. The water contact angle is a value measured by the static drop method described in JIS R 3257:1999.

[0185] The surface of this molded article with the modified layer can also be laminated and bonded to other substrates. In this case, the peel strength at the interface between this molded article and other substrates that are the objects of lamination is preferably 8 N / cm or more, and more preferably 10 N / cm or more.

[0186] Hot pressing is an example of a method for laminating and bonding this molded article to other substrates. The hot pressing temperature is preferably below the melting point of the polymer F, more preferably below 300°C, and even more preferably below 240°C. The hot pressing temperature is preferably above 120°C, and even more preferably above 160°C. Because this molded article has a modified layer with excellent wettability and other physical properties on its surface, it can be laminated and bonded to other substrates at even lower temperatures.

[0187] Other substrates, besides the metal substrates and resin substrates mentioned above, include prepregs, glass substrates, and ceramic substrates.

[0188] Examples of structures for a laminate of this molded article and other substrates include metal substrate / molded article with modified layers on both sides / other substrate layer / molded article with modified layers on both sides / metal substrate, metal substrate layer / other substrate layer / molded article with modified layers on both sides / other substrate layer / metal substrate layer, etc. Each layer may also contain glass cloth or filler.

[0189] The aforementioned laminates can be used as antenna components, printed circuit boards, aircraft components, automotive components, sports equipment, food industry supplies, coatings, cosmetics, etc. Specifically, they can be used as wire sheathing materials (aircraft wires, etc.), electrical insulating tapes, oil drilling insulating tapes, printed circuit board materials, separation membranes (precision filtration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode adhesives (for lithium secondary batteries, fuel cells, etc.), photocopier rollers, covers for furniture, motor vehicle dashboards, and household appliances, sliding components (load bearings, sliding shafts, valves, bearings, gears, cams, belt conveyors, food conveyor belts, etc.), tools (shovels, files, awls, saws, etc.), boilers, hoppers, pipes, ovens, baking molds, chutes, plastic molds, toilets, and container covering materials.

[0190] The present invention has been described above in terms of the present method, the present method 1 and the present method 2, and the molded article, but the present invention is not limited to the above-described embodiments.

[0191] For example, in the above-described embodiments, Method 1 and Method 2 can be modified by adding any other step or by replacing it with any step that performs the same function. Furthermore, in the above-described embodiments, the molded article can be modified by adding any other structure or by replacing it with any structure that performs the same function.

[0192] Example

[0193] The present invention will now be described in detail through examples, but the present invention is not limited thereto.

[0194] [Example 1] Example of manufacturing modified powder and liquid compositions

[0195] The following raw materials were used.

[0196] Powder F 1: A powder (average particle size: 2.6 μm) composed of polymer 1 (melting point: 300 °C, fluorine content: 71% by mass) comprising 97.9 mol% TFE units, 2.0 mol% PPVE units and 0.1 mol% NAH units. Powder F 1 corresponds to the resin powder (A) described in paragraph 0154 of International Publication No. 2018 / 016644.

[0197] F powder 2: Powder composed of polymer 2 (melting point: 300℃, fluorine content: 71% by mass) containing 98.7 mol% TFE units and 1.3 mol% PPVE units (average particle size: 4.3 μm).

[0198] In polymer 1, relative to each 1×10 6 Each main chain carbon has 1000 carbonyl groups, and in polymer 2, relative to each 1×10 6 Each main chain has 40 carbon atoms containing carbonyl groups.

[0199] [Example 1-1] Example of manufacturing modified powder 1 and liquid composition 1

[0200] In a plasma chamber containing a dielectric material sandwiched between a pair of opposing electrodes, a mechanism for generating plasma based on a dielectric barrier discharge, and a stage for holding the powder, F powder 1 was uniformly arranged. A mixture of 95% by volume Ar and 5% by volume hydrogen was introduced into the chamber, shielding it from external gases. The combined concentration of Ar and hydrogen in the chamber was maintained above 99.9% by volume during plasma treatment, and the pressure and temperature within the chamber were maintained at 0.1 MPa and 25°C, respectively. The treatment frequency was set to 13 kHz, the applied voltage was set to 9 kV, and plasma discharge was performed in the chamber to treat F powder 1 for 1 minute, resulting in modified powder 1.

[0201] Add 67 parts by mass of distilled water to 33 parts by mass of modified powder 1, and stir for 60 minutes to obtain a liquid composition 1 containing modified powder 1 and water, and free of surfactants, in which modified powder 1 is dispersed.

[0202] [Example 1-2] Evaluation Example

[0203] A mixture consisting of 1 part by mass of a nonionic fluorinated surfactant (Ftergent 250, manufactured by Neos Corporation) and 66 parts by mass of distilled water was added to 33 parts by mass of powder 1, and the mixture was stirred for 60 minutes to obtain a liquid composition C1 in which powder 1 is dispersed. This liquid composition C1 is equivalent to the dispersion (C-1) described in paragraph 0156 of International Publication No. 2018 / 016644. The "dispersibility" evaluation described in the examples of International Publication No. 2018 / 016644 was performed on liquid composition 1 and liquid composition C1, and the results showed that both liquid compositions exhibited equivalent dispersibility.

[0204] [Examples 1-3] Examples of manufacturing modified powder 2 and liquid composition 2

[0205] Except for changing F powder 1 to F powder 2, the same procedure as in Example 1-1 was followed to obtain modified powder 2 and liquid composition 2.

[0206] [Examples 1-4] Examples of manufacturing modified powder 3 and liquid composition 3

[0207] Except for changing F powder 1 to F powder 2, not specifically shielding external gas during plasma discharge, making the total concentration of Ar gas and hydrogen gas in the plasma processing chamber less than 99.9%, and making oxygen greater than 1% by volume during plasma discharge, the modified powder 3 was obtained by operating in the same manner as in Example 1-1, and a liquid composition 3 was obtained.

[0208] [Examples 1-5] Evaluation Examples

[0209] Liquid composition C2 was prepared in the same manner as in Examples 1-2, except that F powder 1 was replaced with F powder 2.

[0210] The adhesive properties of the molded articles of liquid compositions 2, 3 and C2 were evaluated by the following steps.

[0211] The liquid compositions were coated onto copper foil using a molding method, and then passed through a drying oven at 120°C for 5 minutes to form a dried film on the copper foil surface. The film was then further passed through a far-infrared furnace at 380°C for 10 minutes to calcine the polymer, thus preparing a laminate with a polymer layer (10 μm thick) on the copper foil surface. A rectangular test piece, 100 mm long and 10 mm wide, was cut from this laminate, and the copper foil was peeled off from the polymer layer from one end of the test piece to a position 50 mm along its length.

[0212] During peeling, a tensile testing machine (manufactured by Orientec Co., Ltd.) was used to peel the laminate at a 90-degree angle with a tensile speed of 50 mm / min, centered at a position 50 mm away from one end of the test piece along its length. The average load at a measurement distance of 10 mm to 30 mm was measured to evaluate the peel strength (N / cm) of the laminate.

[0213] The peel strength of the laminate formed by liquid composition 2 is 8 N / cm, the peel strength of the laminate formed by liquid composition 3 is 4 N / cm, and the peel strength of the laminate formed by liquid composition C2 is less than 3 N / cm.

[0214] [Example 2] Example of manufacturing modified membranes

[0215] The following raw materials were used.

[0216] Membrane 1: Membrane of polymer F 1 (thickness: 25 μm).

[0217] Membrane 2: A membrane (thickness: 25 μm) of polymer 3 (melting point: 305 °C, fluorine content: 71% by mass) containing 98.2 mol% TFE units and 1.8 mol% PPVE units.

[0218] In membranes 1 and 2, the peak H (located at 284 eV to 286 eV in the region from the membrane surface to a depth of 10 nm) measured by ESCA is weak. The maximum height of peak H is less than 0.2 times smaller than the maximum height of peak F (located at 289 eV to 295 eV in the region from the membrane surface to a depth of 10 nm), which is sufficiently small. The fluorine atom content is 60%.

[0219] In addition, the ESCA-based surface measurements used a Quantera II (manufactured by ULVAC-PHI Corporation). A monochromatic AlKα X-ray source of 100W was used, employing an ion gun and a neutralization gun with a barium oxide emitter to prevent surface charging. The photoelectron detection area was set to 100 μmφ, the photoelectron detection angle to 45 degrees, and the pass energy to 55 eV. Furthermore, the proportion of fluorine atoms was calculated based on the measured peak intensities (N1s, O1s, C1s, and F1s orbitals). The depth from the surface was also determined based on the sputtering rate of the SiO2 sputtered film using C60 ions as sputtering ions.

[0220] [Example 2-1] Manufacturing example of modified film 1

[0221] A membrane 1 is disposed within a plasma chamber containing a dielectric material sandwiched between a pair of opposing electrodes and a mechanism for generating plasma based on a dielectric barrier discharge. A mixture of 95% by volume Ar and 5% by volume hydrogen is introduced into the chamber, shielding it from external gases, maintaining the pressure within the chamber at 0.1 MPa and the temperature at 25°C. A plasma discharge is performed within the chamber at a processing frequency of 13 kHz and an applied voltage of 9 kV for 2 minutes, subjecting the membrane 1 to plasma treatment.

[0222] In the surface of the obtained film (modified film 1), the maximum height of peak H is 2.5 times that of peak F, and the fluorine atom content in the above region is 30%. In addition, the surface of modified film 1 was etched 100 nm in the thickness direction, and its surface was measured again by ESCA. The results confirmed that its profile was the same as that of film 1. Modified film 1 is a film with a modified layer formed by introducing hydrogen atoms into polymer 1 on its surface.

[0223] [Example 2-2] Manufacturing example of modified film 2

[0224] Except that the gas sealed in the chamber was changed to a mixture of 94% by volume Ar, 5% by volume ammonia and 1% by volume water vapor, the membrane 1 was subjected to plasma treatment in the same manner as in Example 1.

[0225] On the surface of the obtained film (modified film 2), the maximum height of peak H is 0.2 times that of peak F, confirming that modified film 2 is a film with a modified layer formed on the surface by introducing hydrogen atoms into polymer 1.

[0226] [Example 2-3] Manufacturing example of modified film 3

[0227] Except for replacing membrane 1 with membrane 2, the same procedure as in Example 1 was followed, and membrane 2 was subjected to plasma treatment.

[0228] On the surface of the obtained film (modified film 3), the maximum height of peak H is 3 times that of peak F, and the fluorine atom content in the above region is 25%, confirming that modified film 3 is a film with a modified layer formed by introducing hydrogen atoms into polymer 2 on its surface.

[0229] [Examples 2-4] Manufacturing examples of modified membrane 4 (comparative examples)

[0230] Except that the gas sealed in the chamber was only Ar, the membrane 1 was subjected to plasma treatment in the same manner as in Example 1.

[0231] The surface state of the membrane (modified membrane 4) obtained by ESCA measurement is basically the same as that of membrane 1.

[0232] [Examples 2-5] Manufacturing examples of modified film 5 (comparative examples)

[0233] Except for setting the conditions to vacuum, the membrane 1 was subjected to plasma treatment in the same manner as in Example 1.

[0234] The surface state of the membrane (modified membrane 5) obtained by ESCA measurement is basically the same as that of membrane 1.

[0235] [Examples 2-6] Evaluation of modified membranes

[0236] Modified film 1 and a clean copper foil were placed facing each other and hot-pressed (temperature: 340℃, pressure: 15kN / m) to obtain an adhesive laminate of modified film 1 and copper foil. A rectangular test piece with a length of 100mm and a width of 10mm was cut from this adhesive laminate and left to stand at 25℃ for 3 months. Then, the copper foil layer was peeled off from modified film 1 from one end of the test piece to a position 50mm along its length. During peeling, using a tensile testing machine (manufactured by Orientec Co., Ltd.) with a tensile speed of 50mm / min, a 90-degree peel was performed with the center at a distance of 50mm from one end of the test piece along its length. The average load over a distance of 10mm to 30mm was measured as the peel strength (N / cm).

[0237] For each membrane, adhesive laminates were also fabricated in the same manner, and their peel strength was evaluated. The results are summarized in Table 1.

[0238] [Table 1]

[0239] Table 1

[0240]

[0241] Industrial applications

[0242] The results above clearly show that the modified powder prepared by this method is not prone to sedimentation, and its dispersibility in water is the same as that when a surfactant is added, even without the addition of surfactant. It is also evident that molded articles formed from liquid compositions containing the modified powder prepared by this method exhibit higher adhesion to the substrate and stronger bonding properties compared to molded articles formed from liquid compositions containing the original powder.

[0243] As can be seen from the above, the modified powder based on this method is highly surface modified. The composition containing this modified powder will become a liquid composition with excellent dispersibility and other liquid properties even without the addition of surfactants, and can form a molded article with high substrate adhesion.

[0244] Liquid compositions containing modified powders based on this method are liquid compositions with excellent dispersibility and other liquid properties, and can be efficiently impregnated in porous or fibrous materials.

[0245] Furthermore, the above results clearly show that when the modified molded articles prepared by this method, i.e., modified films 1 to 3, are bonded to copper foil, the peel strength is higher than that of films 1 or 2 as the original molded articles, indicating that the adhesion strength has been improved. Moreover, the peel strength of modified films 1 to 3 based on this method to copper foil is higher than that of modified films 4 and 5 not prepared according to this method. Therefore, the modified molded articles based on this method are highly surface-modified.

[0246] Therefore, it is believed that the modified molded articles based on this method and the laminates with other substrates can be used as antenna components, printed circuit boards, aircraft components, automotive components, sports equipment, food industry products, coatings, cosmetics, etc.

Claims

1. A method for manufacturing a modified molded article, comprising plasma treatment of at least a portion of the surface layer of a molded article having a surface layer comprising a tetrafluoroethylene-based polymer containing units based on perfluoro(alkyl vinyl ether) or hexafluoropropylene with a melting temperature of 200–325°C under an atmosphere containing any one of hydrogen or ammonia and a rare gas and shielding it from air, such that at least a portion of the surface has a modified layer with a thickness of 1 nm or more and 100 nm or less formed by introducing hydrogen atoms into the tetrafluoroethylene-based polymer. in, The total concentration of either hydrogen or ammonia and the rare gas in the atmosphere is above 99.9% by volume. In the modified layer, the maximum height of the peak located at 284eV to 286eV in the region from the surface to a depth of 1nm, as determined by X-ray photoelectron spectroscopy, is more than 0.2 times the maximum height of the peak located at 289eV to 295eV in the same region, and the fluorine atom content in the region is less than 55%.

2. The manufacturing method as described in claim 1, characterized in that, Before performing the plasma treatment, the surface layer is pre-treated with plasma in an atmosphere free of reducing gases.

3. The manufacturing method as described in claim 1 or 2, characterized in that, The tetrafluoroethylene polymers have atomic groups containing oxygen atoms.

4. A modified molded article comprising a tetrafluoroethylene polymer, wherein at least a portion of its surface has a modified layer of thickness greater than 1 nm and less than 100 nm formed by introducing hydrogen atoms into a tetrafluoroethylene polymer comprising units based on perfluoro(alkyl vinyl ether) or hexafluoropropylene at a melting temperature of 200–325 °C, wherein the maximum height of the peak located at 284 eV–286 eV in a region from the surface to a depth of 1 nm, as determined by X-ray photoelectron spectroscopy, is more than 0.2 times the maximum height of the peak located at 289 eV–295 eV in the same region, and the fluorine atom content in the region is less than 55%.

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