Telecommunications articles and methods including crosslinked fluoropolymers

Abstract

Telecommunication articles comprising a crosslinked fluoropolymer layer are described. In typical embodiments, the crosslinked fluoropolymer layer is a substrate, a patterned (e.g., photoresist) layer, an insulating layer, a passivation layer, a cladding, a protective layer, or a combination thereof. Methods for making telecommunication articles and forming patterned fluoropolymer layers are also described. The fluoropolymer preferably comprises at least 80, 85, or 90 weight percent polymerized units of a perfluorinated monomer and a cure site selected from nitrile, iodine, bromine, and chlorine. Exemplary telecommunication articles include integrated circuits, printed circuit boards, antennas, and fiber optic cables. Fluoropolymer compositions are also described.

Description

Summary of the Invention

[0001] In one embodiment, electronic telecommunication articles are described that include a crosslinked fluoropolymer layer. In a typical embodiment, the crosslinked fluoropolymer layer is a substrate, a patterned (e.g., photoresist) layer, an insulating layer, a passivation layer, a cladding, a protective layer, or a combination thereof.

[0002] In another embodiment, a method of making a telecommunications article is described, comprising providing a film or coating solution comprising a fluoropolymer and applying the film or coating solution to a component of the telecommunications article. The coating solution typically further comprises a fluorinated solvent. The method further comprises crosslinking the fluoropolymer by exposure to heat, actinic radiation, or a combination thereof.

[0003] In another embodiment, a method for forming a patterned fluoropolymer layer is described that includes applying a fluoropolymer film to a substrate, selectively crosslinking portions of the fluoropolymer film by exposure to actinic radiation, and removing uncrosslinked portions of the fluoropolymer film.

[0004] In each of these embodiments, the fluoropolymer preferably comprises at least 80, 85, or 90% by weight polymerized units of perfluorinated monomers and cure sites selected from nitrile, iodine, bromine, and chlorine.

[0005] Exemplary telecommunications articles include integrated circuits, printed circuit boards, antennas, and fiber optic cables. [Brief explanation of the drawings]

[0006] [Figure 1]1A-1C are schematic cross-sectional views of forming a patterned fluoropolymer layer by photolithography in an exemplary embodiment of integrated circuit (IC) fabrication. [Figure 2] FIG. 1 is a perspective view of an exemplary printed circuit board (PCB) containing an integrated circuit. [Figure 3A] 1 is a cross-sectional view of an exemplary fluoropolymer passivation layer and insulating layer. [Figure 3B] 1 is a cross-sectional view of an exemplary fluoropolymer passivation layer and insulating layer. [Figure 4] FIG. 2 is a plan view of an exemplary antenna for a mobile computing device. [Figure 5A] 1 is a perspective view of an exemplary antenna on a communications tower. [Figure 5B] 1 is a perspective view of an exemplary antenna on a communications tower. [Figure 6] 1 is a cross-sectional view of an exemplary fiber optic cable. DETAILED DESCRIPTION OF THE INVENTION

[0007] Described herein are certain fluoropolymer compositions (e.g., films and coatings) for use in telecommunications articles. As used herein, electronic refers to devices that use the electromagnetic spectrum (e.g., electrons, photons), while communication is the transmission of signs, signals, messages, words, sentences, images, and sounds, or information of any nature, by wire, wireless, optical, or other electromagnetic systems.

[0008] Polyimide materials are widely used in the telecommunications industry. The structure of poly-oxydiphenylene-pyromellitimide, "Kapton," is as follows: [ka]

[0009] Polyimide films have a dielectric constant value in the range of 2.78 to 3.48 at 1 Hz at room temperature and a dielectric constant of 0.01 to 0.03. tangent The material exhibited excellent insulating properties.

[0010] Perfluoropolymers have substantially lower dielectric constants and dielectric constants than polyimides, which are particularly important for fifth-generation cellular network technology ("5G") articles. tangent For example, the crosslinked fluoropolymer compositions described herein may have a dielectric constant (Dk) of less than 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, or 1.95. In some embodiments, the dielectric constant is at least 2.02, 2.03, 2.04, 2.05. Furthermore, the crosslinked fluoropolymer compositions described herein may have low dielectric constants. tangent , typically less than 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002, 0.001, 0.0009, 0.0008, 0.0007, 0.0006, 0.0005, 0.0004, 0.0003. tangent is at least 0.00022, 0.00023, 0.00024, 0.00025. Dielectric properties (e.g., constant and loss) can be determined according to the test methods described in the Examples. As the number of non-fluorine atoms increases (e.g., the number of carbon-hydrogen and / or carbon-oxygen bonds increases), the dielectric constant and dielectric tangent also typically increases.

[0011] However, perfluoropolymers have not been used to replace polyimides, and various electrical communication articles at least partially lack perfluoropolymer materials that can be crosslinked by exposure to actinic radiation, more preferably ultraviolet radiation.Crosslinked perfluoropolymer materials can have improved mechanical properties compared with uncrosslinked perfluoropolymer materials.Therefore, the perfluoropolymer compositions described are suitable for use in various electrical communication articles to replace polyimides.

[0012] In one embodiment, the telecommunications article is an integrated circuit, or in other words a silicon chip or microchip, i.e., a microscopic electronic circuit array formed by the fabrication of various electrical and electronic components (resistors, capacitors, transistors, etc.) on a wafer of semiconductor material (silicon).

[0013] In one embodiment, the fluoropolymer compositions described herein can be used to form patterned (e.g., photoresist) layers. The fluoropolymer compositions described herein can be used as negative photoresists in a variety of fabrication techniques. In some embodiments, the (e.g., sacrificial) photoresist material is etched away and does not remain in the finished article. In other embodiments, the photoresist material can be present in the finished article. Various integrated circuit designs are described in the literature.

[0014] Referring to FIG. 1, in one embodiment, a method for forming a patterned fluoropolymer layer is described that includes applying a fluoropolymer film 100 to a substrate (e.g., a silicon wafer 120 or a surface thereof coated with a passivating (e.g., SiO2) layer 125), selectively crosslinking portions of the fluoropolymer film by exposure to actinic radiation, and removing uncrosslinked portions of the fluoropolymer film.

[0015] In some embodiments, the method further includes providing a mask (e.g., a photomask) 130 having one or more openings between the fluoropolymer film 100 and a source of actinic (e.g., electron beam or UV) radiation 140, and exposing the fluoropolymer film to actinic radiation through at least one opening in the mask.

[0016] As known in the art, a mask includes actinic energy (e.g., UV light) transmitting portions and portions that are opaque to actinic energy (e.g., UV light). A photomask typically comprises a transparent substrate having an opaque mask pattern on the surface of the substrate. The substrate is typically glass (e.g., high-purity quartz) and is transparent to the illumination (i.e., wavelength and intensity) of the photolithography process used. Masks are typically prepared by selective deposition or selective etching of a mask material. Common opaque mask materials include chromium metal, iron oxide, molybdenum silicide, and the like, as known in the art.

[0017] After exposure, the fluoropolymer film comprises a patterned fluoropolymer layer that includes portions of cured or otherwise crosslinked fluoropolymer 150 and uncured or otherwise uncrosslinked fluoropolymer 175 .

[0018] In some embodiments, the method further comprises removing portions of the uncrosslinked fluoropolymer film by dissolving the uncrosslinked portions in solvent 160 (e.g., washing the fluoropolymer film with a fluorinated solvent). Portions of the cured or otherwise crosslinked fluoropolymer 150 remain on the surface of the substrate as a patterned fluoropolymer layer. In this embodiment, the substrate or its (e.g., SiO2) coated surface that comes into contact with the solvent is substantially insoluble in the solvent utilized to remove the uncrosslinked portions of the fluoropolymer film. In a preferred embodiment, the solvent is a fluorinated solvent.

[0019] In some embodiments, particularly when it is desired to apply a thin fluoropolymer film to a substrate, the method includes applying a coating solution (e.g., spin coating) to the substrate, the coating solution including a fluorinated solvent and a fluoropolymer. In some embodiments, the fluoropolymer preferably includes primarily polymerized units of perfluorinated monomers and cure sites. The coating further includes a curing agent that reacts with the cure sites in the presence of chemical (e.g., UV) radiation, thereby crosslinking the fluoropolymer. The method typically includes removing the fluorinated solvent (e.g., by evaporation). In this embodiment, the substrate or its (e.g., SiO2) coated surface that comes into contact with the solvent is substantially insoluble in the fluorinated solvent of the coating solution. The fluorinated solvent used to remove the uncrosslinked portions of the fluoropolymer film and the fluorinated solvent of the coating solution can be the same or different fluorinated solvents. Furthermore, the method typically includes recycling or otherwise reusing the fluorinated solvent utilized to remove the uncrosslinked portions of the fluoropolymer film and / or the fluorinated solvent of the coating solution.

[0020] In other embodiments, the uncured portion 175 may be removed by other solvent-free methods, such as laser ablation.

[0021] The patterned fluoropolymer layer can be used to fabricate other layers, such as circuits of patterned electrode materials. Suitable electrode materials and deposition methods are known in the art. Such electrode materials include, for example, inorganic or organic materials, or composites of the two. Exemplary electrode materials include polyaniline, polypyrrole, poly(3,4-ethylenedioxythiophene) (PEDOT) or doped conjugated polymers, as well as dispersions or pastes of particles of graphite or metals such as Au, Ag, Cu, Al, Ni, or mixtures thereof, as well as sputter-coated or evaporated metals such as Cu, Cr, Pt / Pd, Ag, Au, Mg, Ca, Li, or mixtures thereof, or metal oxides such as indium tin oxide (ITO), F-doped ITO, GZO (gallium doped zinc oxide), or AZO (aluminum doped zinc oxide). Organometallic precursors can also be used and deposited from the liquid phase.

[0022] In another embodiment, a fluoropolymer (e.g., photoresist) layer can be disposed on a metal (e.g., copper) substrate in the manufacture of a printed circuit board (PCB). An exemplary perspective view of a printed circuit board is shown in FIG. 2. Printed circuit boards (or PCBs) are used to mechanically support and electrically connect electronic components using conductive paths, tracks, or signal traces etched from a (e.g., copper) metal sheet laminated onto a non-conductive substrate. Such substrates are typically made from insulating materials such as glass fiber reinforced epoxy resin or paper reinforced phenolic resin. The electrical pathways are typically created from a negative photoresist, as previously described. Thus, in this embodiment, a cross-linked fluoropolymer is disposed on the surface of a (e.g., copper) metal substrate. Portions of the uncross-linked fluoropolymer are removed to form conductive (e.g., copper) pathways. The cross-linked fluoropolymer (e.g., photoresist) remains present and is disposed between the conductive (e.g., copper) pathways of the printed circuit board. Solder is used to attach components to the surfaces of these substrates. In some embodiments, the printed circuit board further comprises an integrated circuit 200, as shown in Figure 2. Printed circuit board assemblies have applications in nearly every electronic item, including computers, computer printers, televisions, and cell phones.

[0023] In another embodiment, the crosslinked fluoropolymer films described herein may be utilized as insulating, passivating, and / or protective layers in the manufacture of integrated circuits.

[0024] Referring to FIG. 3A, in one embodiment, a thin fluoropolymer film 300 (e.g., typically having a thickness of less than 50, 40, or 30 nm) may be disposed on a passivation layer 310 (e.g., SiO2) disposed on an electrode-patterned 360 silicon chip 320.

[0025] Referring to Figure 3B, in another embodiment, a thin fluoropolymer film 300 (e.g., typically having a thickness of at least 100, 200, 300, 400, 500 nm) can be disposed on an electrode-patterned 360 silicon chip 320. In this embodiment, the fluoropolymer layer can function as both a passivation layer and an insulating layer. Passivation is the use of a thin coating to provide electrical stability by isolating the transistor surface from the electrical and chemical conditions of the environment.

[0026] In another embodiment, the crosslinked fluoropolymer films described herein can be utilized as a substrate for an antenna. A transmitter antenna emits energy into space (e.g., radio frequency) while a receiver antenna captures the energy and converts it into electricity.

[0027] The patterned electrodes of the antenna can also be formed by photolithography. Screen printing, flexography, and inkjet printing can also be used to form electrode patterns, as known in the art. Various antenna designs for (e.g., mobile) computing devices (smartphones, tablets, laptops, desktops) have been described in the literature. One representative split-ring monopole antenna is shown in Figure 4, with the following dimensions in microns: [Table 1]

[0028] The low dielectric fluoropolymer films and coatings described herein can also be utilized as insulating and protective layers for transmitter antennas on cell towers and other (e.g., outdoor) structures. There are two main types of antennas used on cell towers. Figure 5A shows a typical omnidirectional (e.g., dipole) antenna used to transmit / receive in any direction. Figure 5B shows a typical directional antenna used to transmit / receive only in a specific desired direction, such as circular and rectangular types of horn antennas.

[0029] In another embodiment, the low dielectric fluoropolymer compositions described herein can also be utilized in optical fiber cables. Referring to FIG. 6, optical fiber cables typically include five major components: a core, which is typically high-purity (e.g., silica) glass 620; a cladding 630; a coating (e.g., a first inner protective layer) 640; a reinforcing fiber 650; and an outer jacket (i.e., a second outer protective layer) 660. The function of the cladding is to provide a lower refractive index at the core interface to cause reflections within the core as light waves transmit through the fiber. The coating on the cladding is typically present to reinforce the fiber core, absorb shock, and provide extra protection against excessive cable bending. The low dielectric fluoropolymer compositions described herein can be used as the cladding, coating, outer jacket, or a combination thereof.

[0030] In other embodiments, the low dielectric fluoropolymer films and coatings described herein can also be utilized as insulating films on flexible cables and magnet wires. For example, in a laptop computer, the cable connecting the main logic board to the display (which must flex each time the laptop is opened and closed) can be a low dielectric fluoropolymer composition described herein with copper conductors.

[0031] Telecommunications articles are typically not sealing components of the equipment used in wafer and chip manufacturing.

[0032] Those skilled in the art will appreciate that the low dielectric fluoropolymer compositions described herein can be utilized in a variety of telecommunications articles, particularly in place of polyimides, and that such utility is not limited to the specific articles described herein.

[0033] The fluoropolymers described herein are copolymers that contain polymerized units derived primarily or exclusively (e.g., repeating) from two or more perfluorinated comonomers. Copolymers refer to polymeric materials resulting from the simultaneous polymerization of two or more monomers. In some embodiments, the comonomers include tetrafluoroethene (TFE) and one or more unsaturated perfluoro(e.g., alkenyl, vinyl) alkyl ethers.

[0034] In some preferred embodiments, the one or more unsaturated perfluoroalkyl ethers have the general formula: R f -O-(CF2) n -CF=CF2 wherein n is 1 (allyl ether) or 0 (vinyl ether); R f represents a perfluoroalkyl residue optionally interrupted by one or more oxygen atoms. f may contain up to 10 carbon atoms, for example 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. f contains 8 or fewer, more preferably 6 or fewer carbon atoms and most preferably 3 or 4 carbon atoms. f has 3 carbon atoms. In another embodiment, R f has one carbon atom. f R may be linear or branched and may or may not contain cyclic units. f Specific examples of include residues having one or more ether functional groups, including, but not limited to: -(CF2)-O-C3F7, -(CF2)2-O-C2F5, -(CF2) r3 -O-CF3, -(CF2-O)-C3F7, -(CF2-O)2-C2F5, -(CF2-O)3-CF3, -(CF2CF2-O)-C3F7, -(CF2CF2-O)2-C2F5, -(CF2CF2-O)3-CF3

[0035] R f Other specific examples of include residues that do not contain an ether functionality, including, but not limited to, -CF, -CF, -CF, -CF, where the C and C residues may be branched or linear, but are preferably linear.

[0036] Specific examples of suitable perfluoroalkyl vinyl ethers (PAVEs) and perfluoroalkyl allyl ethers (PAAEs) include perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE), perfluoro(n-propyl vinyl) ether (PPVE-1), perfluoro-2-propoxypropyl vinyl ether (PPVE-2), perfluoro-3-methoxy-n-propyl vinyl ether, perfluoro-2-methoxy-ethyl vinyl ether, CF₂=CF—O—CF₂—O—CF 5、 CF2=CF-O-CF2-O-C3F7, [ka] and their allyl ether homologues. Specific examples of allyl ethers include CF2=CF-CF2-O-CF3, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-(CF3)3-O-CF3.

[0037] Further examples include, but are not limited to, the vinyl ethers described in European Patent Application No. 1,997,795(B1).

[0038] Such perfluorinated ethers are commercially available, for example, from Anles Ltd. (St. Petersburg, Russia) and other companies, or can be prepared according to the methods described in U.S. Pat. No. 4,349,650 (Krespan) or European Patent No. 1,997,795, or modifications thereof known to those skilled in the art.

[0039] In some embodiments, one or more unsaturated perfluoroalkyl ethers comprise unsaturated cyclic perfluoroalkyl ethers such as 2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole. In other embodiments, the fluoropolymer is substantially free of unsaturated cyclic perfluoroalkyl ethers such as 2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole. By substantially free, it is meant that the amount is zero or sufficiently low, and the fluoropolymer properties are approximately the same.

[0040] In some preferred embodiments, the fluoropolymer is derived primarily or exclusively from perfluorinated comonomers, including tetrafluoroethene (TFE) and one or more of the unsaturated perfluoroalkyl ethers listed above. As used herein, "predominantly" means that at least 80, 85, or 90 wt.% of the polymerized units of the fluoropolymer are derived from such perfluorinated comonomers, such as tetrafluoroethene (TFE) and one or more unsaturated perfluoroalkyl ethers, based on the total weight of the fluoropolymer. In some embodiments, the fluoropolymer contains at least 81, 82, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, or 97 wt.% or more of such perfluorinated comonomers, based on the total weight of the fluoropolymer. The fluoropolymer may contain at least 40, 45, or 50 wt.% of polymerized units derived from TFE. In some embodiments, the maximum amount of polymerized units derived from TFE is 60 wt.% or less.

[0041] The fluoropolymer typically comprises polymerized units derived from one or more unsaturated perfluoroalkyl ethers (PAVEs) (e.g., PMVE, PAAE, or a combination thereof) in an amount of at least 10, 15, 20, 25, 30, 45, or 50 wt. % based on the total polymerized monomer units of the fluoropolymer. In some embodiments, the fluoropolymer comprises up to 50, 45, 40, or 35 wt. % of polymerized units derived from one or more unsaturated perfluoroalkyl ethers (PMVE, PAAE, or a combination thereof) based on the total polymerized monomer units of the fluoropolymer. The molar ratio of units derived from TFE to units derived from the perfluorinated alkyl ethers described above can be, for example, 1:1 to 5:1. In some embodiments, the molar ratio is in the range of 1.5:1 to 3:1.

[0042] Although the fluoropolymer may be thermoplastic, in preferred embodiments, the fluoropolymer is amorphous. As used herein, an amorphous fluoropolymer is a material that is essentially free of crystallinity or has no significant melting point (peak maximum) as determined by differential scanning calorimetry according to DIN EN ISO 11357-3:2013-04 under nitrogen flow and a heating rate of 10°C / min. Typically, amorphous fluoropolymers have a glass transition temperature (Tg) of less than 26°C, less than 20°C, or less than 0°C, for example, from -40°C to 20°C, or from -50°C to 15°C, or from -55°C to 10°C. The fluoropolymer may typically have a Mooney viscosity (ML1+10 at 121°C) of about 2 to about 150, for example, from 10 to 100, or from 20 to 70. For amorphous polymers containing cyclic perfluorinated alkyl ether units, the glass transition temperature is typically at least 70° C., 80° C., or 90° C. and can range up to 220° C., 250° C., 270° C., or 290° C. The MFI (297° C. / 5 kg) is 0.1 to 1000 g / 10 min.

[0043] In other embodiments, the fluoropolymer may have a melting point below 150°C or 100°C.

[0044] The fluoropolymer is preferably a curable fluoropolymer containing one or more cure sites. A cure site is a functional group that reacts in the presence of a curing agent or curing system to crosslink the polymer. Cure sites are typically introduced by copolymerizing a cure site monomer, which is a functional comonomer that already contains a cure site or its precursor. One indication of crosslinking is that the dried and cured coating composition is not soluble in the fluorinated solvent of the coating.

[0045] Cure sites can be introduced into the polymer by using cure site monomers, i.e., functional monomers, functional chain transfer agents, and starter molecules as described below. Fluoroelastomers may contain cure sites that are reactive to more than one class of curative.

[0046] Curable fluoroelastomers may also contain cure sites in the backbone as pendant groups or at terminal positions. Cure sites within the fluoropolymer backbone can be introduced by using suitable cure site monomers. Cure site monomers are monomers that contain one or more functional groups that can act as cure sites, or precursors that can be converted to cure sites.

[0047] In some embodiments, the cure site comprises an iodine atom or a bromine atom.

[0048] Iodine-containing cure site end groups can be introduced by using iodine-containing chain transfer agents in the polymerization, which are described in more detail below. To introduce iodine end groups, halogenated redox systems, such as those described below, can be used.

[0049] In addition to iodine curesites, other curesites may also be present, such as Br-containing curesites or curesites containing one or more nitrile groups. The Br-containing curesites may be introduced by Br-containing curesite monomers.

[0050] Examples of cure site comonomers include, for example: (a) Bromo- or iodo-(per)fluoroalkyl-(per)fluorovinyl ethers, including, for example, those having the formula: ZRf-O-CX=CX2 [wherein each X may be the same or different and represents H or F, Z is Br or I, and Rf is C1-C12 (per)fluoroalkylene optionally containing chlorine atoms and / or ether oxygen atoms]. Suitable examples include ZCF2-O-CF=CF2, ZCF2CF2-O-CF=CF2, ZCF2CF2CF2-O-CF=CF2, CF3CFZCF2-O-CF=CF2, or ZCF2CF2-O-CF2CF2CF2-O-CF=CF2 [wherein Z represents Br or I], (b) Bromo- or iodoperfluoroolefins, such as those having the formula: Z'-(Rf) r -CX=CX2 wherein each X independently represents H or F, Z′ is Br or I, and Rf is a C1-C aryl group optionally containing a chlorine atom. 12 perfluoroalkylene, and r is 0 or 1; and (c) Non-fluorinated bromo- and iodo-olefins such as vinyl bromide, vinyl iodide, 4-bromo-1-butene, and 4-iodo-1-butene.

[0051] Illustrative examples include, but are not limited to, compounds according to (b) where X is H, such as compounds where X is H and Rf is C1-C3 perfluoroalkylene. Specific examples include bromo- or iodo-trifluoroethene, 4-bromo-perfluorobutene-1, 4-iodo-perfluorobutene-1, or bromo- or iodo-fluoroolefins, such as 1-iodo,2,2-difluoroethene, 1-bromo-2,2-difluoroethene, 4-iodo-3,3,4,4-tetrafluorobutene-1, and 4-bromo-3,3,4,4-tetrafluorobutene-1, 6-iodo-3,3,4,4,5,5,6,6-octafluorohexene-1.

[0052] In some embodiments, the cure site comprises a chlorine atom. Such cure site monomers have the general formula: CX1X2=CY1Y2, where X1 and X2 are independently H and F, Y1 is H, F, or Cl, and Y2 is Cl, a fluoroalkyl group (R F ), a fluoroether group having at least one Cl substituent (OR F ), or -CF2-OR F Fluoroalkyl groups (R F ) is typically a partially or fully fluorinated C1-C5 alkyl group. Examples of cure site monomers with chlorine atoms include CF2=CFCl, CF2=CF-CF2Cl, and CF2=CF-O-(CF2) n -Cl[n=1 to 4], CH2=CHCl, and CH2=CCl2.

[0053] Typically, the amount of iodine or bromine or chlorine or a combination thereof in the fluoropolymer is 0.001 to 5 wt%, preferably 0.01 to 2.5 wt%, or 0.1 to 1 wt%, or 0.2 to 0.6 wt%, based on the total weight of the fluoropolymer. In one embodiment, the curable fluoropolymer contains 0.001 to 5 wt%, preferably 0.01 to 2.5 wt%, or 0.1 to 1 wt%, more preferably 0.2 to 0.6 wt%, of iodine, based on the total weight of the fluoropolymer.

[0054] The composition may optionally further comprise a second fluoropolymer that does not have a halogen cure site. The amount of the fluoropolymer that does not have a halogen cure site is typically less than 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5 weight percent of the total fluoropolymer. Thus, the composition has a sufficient amount of fluoropolymer that has a halogen cure site to achieve adequate crosslinking.

[0055] In one embodiment, the composition further comprises a second fluoropolymer derived primarily or exclusively from two or more perfluorinated comonomers comprising tetrafluoroethene (TFE) and one or more unsaturated cyclic perfluoroalkyl ethers, such as 2,2-bistrifluoromethyl-4,5-difluoro-1,3 dioxole. Such fluoropolymers are commercially available as "TEFLON™ AF," "CYTOP™," and "HYFLON™."

[0056] In some embodiments, the second fluoropolymer contains a nitrile-containing cure site. When a combination of fluoropolymers with different cure sites is utilized, the composition may be characterized as dual-cure, containing different cure sites that are reactive to different cure systems.

[0057] Fluoropolymers with halogen cure sites (iodine, bromine, and chlorine) are preferred for UV curing, although fluoropolymers with nitrile-containing cure sites may alternatively be used for thermal or electron beam curing.

[0058] Fluoropolymers having nitrile-containing cure sites are known, such as those described in US Pat. No. 6,720,360.

[0059] The nitrile-containing cure site may be reactive to other cure systems, such as, but not limited to, bisphenol cure systems, peroxide cure systems, triazine cure systems, and especially amine cure systems. Examples of nitrile-containing cure site monomers have the following formula: CF2=CF-CF2-O-Rf-CN, CF2=CFO(CF2) r CN, CF2=CFO[CF2CF(CF3)O] p (CF2) v OCF(CF3)CN, CF2=CF[OCF2CF(CF3)] k O(CF2) u CN, [wherein r represents an integer of 2 to 12, p represents an integer of 0 to 4, k represents 1 or 2, v represents an integer of 0 to 6, u represents an integer of 1 to 6, and Rf represents a perfluoroalkylene or divalent perfluoroether group.] Specific examples of nitrile-containing fluorinated monomers include, but are not limited to, perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene), CF2=CFO(CF2)5CN, and CF2=CFO(CF2)3OCF(CF3)CN.

[0060] In some embodiments, the amount of nitrile-containing cure site comonomer is typically at least 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 wt. % based on the total weight of the fluoropolymer, and typically no more than 10 wt. %. Suitable curing agents for nitrile cure sites are known in the art and include, but are not limited to, (e.g., fluorinated) amidines, amidoximes, and others described in WO 2008 / 094758 A1, which is incorporated herein by reference. Representative curing agents include, for example, bis-tetraphosphonium perfluoroadipate, methyl sulfone, tetrabutylphosphonium tolui-hexafluoroisopropoxide trifluoromethoxy, and tetrafluoropropyl amidine.

[0061] In one embodiment, fluoropolymers with nitrile-containing cure sites can be combined with peroxides and ethylenically unsaturated compounds as curing agents, as described in WO 2018 / 107017. In this embodiment, suitable organic peroxides are those that generate free radicals at cure temperatures. Examples include dialkyl peroxides or bis(dialkyl peroxides), such as di-tert-butyl peroxide, which has a tertiary carbon atom attached to the peroxy oxygen. Specific examples include 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3 and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, dibenzoyl peroxide, tert-butyl perbenzoate, α,α'-bis(t-butylperoxy-diisopropylbenzene), and di[1,3-dimethyl-3-(t-butylperoxy)-butyl]carbonate. Generally, about 1 to 5 parts of peroxide per 100 parts of fluoropolymer can be used.

[0062] In other embodiments, the composition is substantially free of fluoropolymers having nitrile-containing cure sites. In this embodiment, the composition is also free of curing agents that react with nitrile groups.

[0063] In other embodiments, halogenated chain transfer agents can be utilized to provide terminal cure sites. Chain transfer agents are compounds that can react with growing polymer chains and terminate chain growth. Examples of chain transfer agents that have been reported for the production of fluoroelastomers include those of the formula RI x where R is an x-valent fluoroalkyl or fluoroalkylene group having 1 to 12 carbon atoms, which may be interrupted by one or more ether oxygens and may contain chlorine and / or bromine atoms. R may be Rf, which may be an x-valent (per)fluoroalkyl or (per)fluoroalkylene group, which may be interrupted one or more times by ether oxygens. Examples include α-ω diiodoalkanes, α-ω diiodofluoroalkanes, and α-ω diiodoperfluoroalkanes, which may contain one or more catenary ether oxygens. The "α-ω" indicates that the iodine atoms are at the terminal positions of the molecule. Such compounds can be represented by the general formula XRY, where X and Y are I, and R is as defined above. Specific examples include diiodomethane, α-ω (or 1,4-) diiodobutane, α-ω (or 1,3-) diiodopropane, α-ω (or 1,5-) diiodopentane, α-ω (or 1,6-) diiodohexane, and 1,2-diiodoperfluoroethane. [ka] wherein X is independently selected from F, H, and Cl; f and R' f are independently selected from F and monovalent perfluoroalkanes having 1 to 3 carbons, R is F or a partially or fully fluorinated alkane containing 1 to 3 carbons, and R'' fis a divalent fluoroalkylene having 1 to 5 carbons or a divalent fluorinated alkylene ether having 1 to 8 carbons and at least one ether bond; k is 0 or 1; n, m, and p are independently selected from integers of 0 to 5; n+m is at least 1; and p+q is at least 1.

[0064] The fluoropolymer may or may not contain units derived from at least one modifying monomer. The modifying monomer can introduce branching sites into the polymer structure. Typically, the modifying monomer is a bisolefin, a bisolefin ether, or a polyether. The bisolefin and bisolefin (poly)ether may be fully fluorinated, partially fluorinated, or non-fluorinated. Preferably, they are fully fluorinated. Suitable fully fluorinated bisolefin ethers include those represented by the following general formula: CF2=CF-(CF2) n -O-(Rf)-O-(CF2) m -CF=CF2 [wherein n and m are independently 1 or 0, and Rf represents a perfluorinated, linear or branched, cyclic or acyclic, aliphatic or aromatic hydrocarbon residue containing up to 30 carbon atoms, optionally interrupted by one or more oxygen atoms]. A particularly suitable perfluorinated bisolefin ether is a di-vinyl ether represented by the following formula: CF2=CF-O-(CF2) n -O-CF=CF2 [In the formula, n is an integer of 1 to 10, preferably 2 to 6, and for example, n can be 1, 2, 3, 4, 5, 6, or 7.] More preferably, n represents an odd number, such as 1, 3, 5, or 7.

[0065] Further specific examples include bisolefin ethers according to the following general formula: CF2=CF-(CF2) n -O-(CF2) p-O-(CF2) m -CF=CF2 [wherein n and m are independently either 1 or 0, and p is an integer of 1 to 10 or 2 to 6.] For example, n may be selected to represent 1, 2, 3, 4, 5, 6, or 7, preferably 1, 3, 5, or 7.

[0066] Further suitable perfluorinated bisolefin ethers can be represented by the formula: [ka] [In the formula, R af and R bf are different linear or branched perfluoroalkylene groups of 1 to 10 carbon atoms, in particular 2 to 6 carbon atoms, which may or may not be interrupted by one or more oxygen atoms. af and / or R bf may also be a perfluorinated phenyl or substituted phenyl group, n is an integer of 1 to 10, m is an integer of 0 to 10, and preferably m is 0. Furthermore, p and q are independently 1 or 0.

[0067] In another embodiment, the perfluorinated bisolefin ether can be represented by the formula immediately above, wherein m, n, and p are zero, and q is 1-4.

[0068] The modifying monomers can be prepared by methods known in the art and are commercially available, for example, from Anles Ltd. (St. Petersburg, Russia).

[0069] Preferably, no modifiers are used or only small amounts are used. Typical amounts include 0 to 5 wt. %, or 0 to 1.4 wt. %, based on the total weight of the fluoropolymer. The modifiers may be present, for example, in an amount of about 0.1 wt. % to about 1.2 wt. %, or about 0.3 wt. % to about 0.8 wt. %, based on the total weight of the fluoropolymer. Combinations of modifiers may also be used.

[0070] The fluoropolymer may contain partially fluorinated or non-fluorinated comonomers and combinations thereof, but this is not preferred. Typical partially fluorinated comonomers include, but are not limited to, 1,1-difluoroethene (vinylidene fluoride, VDF) and vinyl fluoride (VF) or trifluorochloroethene or trichlorofluoroethene. Examples of non-fluorinated comonomers include, but are not limited to, ethene and propene. The amount of units derived from these comonomers ranges from 0 to 8 wt. % based on the total weight of the fluoropolymer. In some embodiments, the concentration of such comonomers is 7, 6, 5, 4, 3, 2, or 1% or less based on the total weight of the fluoropolymer.

[0071] In a preferred embodiment, the curable fluoropolymer is a perfluoroelastomer containing only repeat units derived (exclusively) from perfluorinated comonomers, but which may also contain units derived from cure site monomers and, if desired, modifying monomers. The cure site monomers and modifying monomers may be partially fluorinated, non-fluorinated, or perfluorinated, preferably perfluorinated. The perfluoroelastomer may contain 69 to 73, 74, or 75 wt. % fluorine (based on the total weight of the perfluoroelastomer). The fluorine content can be achieved by appropriate selection of comonomers and their amounts.

[0072] Such highly fluorinated amorphous fluoropolymers are typically soluble in hydrogen-containing organic liquids only to the extent of at least 1% by weight at room temperature and standard pressure (e.g., they are not soluble in any of methyl ethyl ketone ("MEK"), tetrahydrofuran ("THF"), ethyl acetate, or N-methyl pyrrolidinone ("NMP").

[0073] Fluoropolymers can be prepared by methods known in the art, such as bulk, suspension, solution, or aqueous emulsion polymerization. As described in the art, various emulsifiers can be used, including, for example, 3H-perfluoro-3-[(3-methoxy-propoxy)propanoic acid. For example, the polymerization process can be carried out by free radical polymerization of the monomer alone or as a solution, emulsion, or dispersion in an organic solvent or water. Seeded polymerization may or may not be used. Curable fluoroelastomers that can be used also include commercially available fluoroelastomers, especially perfluoroelastomers.

[0074] The fluoropolymer may have a unimodal, bimodal, or multimodal molecular weight distribution. The fluoropolymer may or may not have a core-shell structure. A core-shell polymer is a polymer in which, towards the end of the polymerization, typically after at least 50 mol% of the comonomer has been consumed, the comonomer composition, comonomer ratio, or reaction rate is changed to form a shell of a different composition.

[0075] The fluorine content of the fluoropolymer is typically at least 60, 65, 66, 67, 68, 69, or 70% by weight of the fluoropolymer, and typically no more than 76, 75, 74, or 73% by weight.

[0076] The fluoropolymer compositions described herein contain one or more ethylenically unsaturated curing agents. The ethylenically unsaturated curing agent is typically present in an amount of at least 1, 1.5, or 2 wt. % based on the total weight of the fluoropolymer. For compositions with a lower amount of crosslinking, the ethylenically unsaturated curing agent may be present in a lower amount, such as at least 0.005, 0.1, 0.2, 0.3, or 0.5 wt. %. The maximum amount of ethylenically unsaturated curing agent is typically no more than 10, 9, 8, 7, 6, or 5 wt. % based on the total weight of the fluoropolymer.

[0077] The ethylenically unsaturated groups of the curing agent are typically (meth)acrylic, including (meth)acrylates RCH=CHCOO- and (meth)acrylamide RCH=CHCONH-, where R is hydrogen or methyl, alkenyl (CH=CH-), including vinyl, or alkynyl.

[0078] Useful multi(meth)acrylate curing agents include: (a) di(meth)acrylic-containing monomers, for example, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol monoacrylate monomethacrylate, ethylene glycol diacrylate, alkoxylated aliphatic diacrylates, alkoxylated cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, alkoxylated neopentyl glycol diacrylate, caprolactone-modified neopentyl glycol hydroxypivalate diacrylate, caprolactone-modified neopentyl glycol hydroxypivalate diacrylate, cyclohexanedimethanol diacrylate, diethylene glycol diacrylate, dipropylene glycol diacrylate, ethoxylated bisphenol A diacrylate, hydroxypivalaldehyde-modified trimethylolpropane diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, tetraethylene glycol diacrylate, tricyclodecane dimethanol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, etc. (b) tri(meth)acrylic-containing monomers, such as glycerol triacrylate, trimethylolpropane triacrylate, ethoxylated triacrylates (e.g., ethoxylated trimethylolpropane triacrylate), propoxylated triacrylates (e.g., propoxylated glyceryl triacrylate, propoxylated trimethylolpropane triacrylate), trimethylolpropane triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, etc. (c) Higher functional (meth)acrylic-containing monomers, such as ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, pentaerythritol triacrylate, ethoxylated pentaerythritol tetraacrylate, and caprolactone-modified dipentaerythritol hexaacrylate.

[0079] In some embodiments, the ethylenically unsaturated curing agent contains at least two or three ethylenically unsaturated groups. The maximum number of ethylenically unsaturated groups is typically 3, 4, 5, or 6. In this embodiment, the ethylenically unsaturated groups are preferably alkenyl groups. Thus, in some embodiments, the composition is substantially free of (meth)acrylate groups.

[0080] The ethylenically unsaturated curing agent may be linear, branched, or contain cyclic groups. The ethylenically unsaturated curing agent may be aliphatic or aromatic. Examples of useful ethylenically unsaturated curing agents include triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, tri(methylallyl)isocyanurate, tris(diallylamine)-s-triazine, triallyl phosphite, (N,N')-diallylacrylamide, hexaallyl phosphoramide, (N,N,N,N)-tetraalkyltetraphthalamide, (N,N,N',N-tetraallylmalonamide, trivinyl isocyanurate, N,N'-m-phenylene bismaleimide, diallyl phthalate, and tri(5-norbornene-2-methylene)cyanurate. In some embodiments, the ethylenically unsaturated curing agent is heterocyclic, such as in the case of triallyl isocyanurate (TAIC).

[0081] In some embodiments, the ethylenically unsaturated curing agent comprises a silicone-containing moiety, such as a silane or siloxane. When the curing agent comprises a silicone-containing moiety, the curing agent can also promote adhesion of the fluoropolymer to the substrate.

[0082] Suitable ethylenically unsaturated curing agents that include a silicone-containing moiety include, for example, diallyldimethylsilane and 1,3-divinyltetramethyldisiloxane.

[0083] In some embodiments, the ethylenically unsaturated curing agent comprises at least one ethylenically unsaturated group and at least one alkoxysilane group.Suitable curing agents include, for example, (meth)acryloylalkoxysilanes, such as 3-(methacryloxy)propyltrimethoxysilane, 3-(methacryloxy)propylmethyldimethoxysilane, 3-(acryloyloxypropyl)methyldimethoxysilane, 3-(methacryloyloxy)propyldimethylmethoxysilane, and 3-(acryloyloxypropyl)dimethylmethoxysilane.In some embodiments, the amount of (meth)acryloylalkoxysilane is at least 2, 3, 4, or 5 wt% to achieve a highly crosslinked fluoropolymer.

[0084] Suitable alkenylalkoxysilanes include vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane, vinyltri-t-butoxysilane, vinyltris-isobutoxysilane, vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, and allyltriethoxysilane.

[0085] In some embodiments, the ethylenically unsaturated curing agent has the general formula: X 1 -L 1 -SiR m (OR 1 ) 3-m [In the formula, X 1 is an ethylenically unsaturated group such as (meth)acrylic or vinyl, L 1 is an organic divalent linking group having 1 to 12 carbon atoms, R is independently C1-C4 alkyl, most typically methyl or ethyl; R 1are independently H or C1-C4 alkyl, most typically methyl or ethyl; m may range from 0 to 2.

[0086] In an exemplary embodiment, L 1 is an alkylene group. In some embodiments, L 1 is an alkylene group having 1, 2, or 3 carbon atoms. 1 comprises or consists of an aromatic group such as phenyl or (eg, C1-C4) alkylphenyl.

[0087] The composition may include a single ethylenically unsaturated curing agent or a combination of ethylenically unsaturated curing agents as described immediately above.

[0088] The compositions described herein further comprise an electron donating group or a precursor thereof. The electron donating group may be present on the same compound, such as in the case of an aminoalkene or a vinylaniline, or the electron donating group may be present as a separate compound.

[0089] The fluoropolymer and / or curing agent contain chromophores, i.e., atoms or groups that absorb light at specific frequencies. In some embodiments, the fluoropolymer and / or curing agent may not have sufficient absorbance independently, but in combination with each other, they do.

[0090] In some embodiments, the fluoropolymer, curing agent, or combination thereof has an absorbance of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 in the wavelength range of 190 nm to 400 nm. In some embodiments, such absorbance is at least 200 nm, 210 nm, 220 nm, 230 nm, or 240 nm. In some embodiments, such absorbance is at wavelengths of 350, 340, 330, 320, 310 nm, or 290 nm or less. In other embodiments, the fluoropolymer, curing agent, or combination thereof has an absorbance of at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 in the wavelength range of 150 nm to 200 nm.

[0091] Without intending to be bound by theory, it is speculated that upon exposure to actinic (e.g., UV) radiation of a suitable wavelength and intensity, halogen atoms in the cure sites of the fluoropolymer become excited and ionized. The ionized halogen atoms react with electron-donating groups, rendering protonated cure sites in place of the former halogen atoms. Such protonated cure sites covalently bond with ethylenically unsaturated groups of the curing agent.

[0092] Although other electron-donating groups can be used, the compound containing the electron-donating group is typically an amine or its precursor. Suitable amines include primary amines, secondary amines, tertiary amines, and combinations thereof. The amines may be aliphatic or aromatic. Amine compounds can also be used to provide a crosslinked fluoropolymer layer by using an amine curing agent to (e.g., thermally) cure a fluoropolymer having a (e.g., nitrile) cure site.

[0093] Exemplary amine compounds include diaminohexane, N,N,N',N'-tetramethyl-1,4-diaminobutane (TMDAB); N,N-dimethylaniline; triethylenetetramine; and diethylenetriamine. In some embodiments, the amine groups are separated by alkylene groups having at least 3, 4, 5, or 6 (e.g., carbon) atoms. Typically, the number of (e.g., carbon) atoms is 12 or less. If the amine compound has an insufficient chain length, it may be a less effective electron-donating group. The alkylene group may optionally include a substituent such as a siloxane, provided that the compound is an electron donor or a precursor thereof.

[0094] In some embodiments, the electron donor compound may be characterized as an electron donor precursor, meaning that the compound is not an electron donor when first combined with the fluoropolymer, however, the precursor compound decomposes or otherwise reacts to form the (e.g., amine) electron donor before or during cure.

[0095] Electron donor precursors include nitrogen-containing nucleophilic compounds such as heterocyclic secondary amines; guanidine; compounds that decompose in situ at temperatures between 40°C and 330°C to form guanidine; compounds that decompose in situ at temperatures between 40°C and 330°C to form primary or secondary amines; compounds of the formula R1-NH-R2, where R1 is H-, C1-C 10 an aliphatic hydrocarbon group or an aryl group having a hydrogen atom at the α-position, and R2 is a C1-C 10 an aliphatic hydrocarbon group, an aryl group having a hydrogen atom at the α-position, -CONHR3, -NHCO2R3, or -OH', where R3 is a C1-C 10 and substituted amidines of the formula HN=CRNRR, where R, R, and R are independently H, alkyl, or aryl groups, and at least one of R, R, and Re is not H.

[0096] As used herein, "heterocyclic secondary amine" refers to an aromatic or aliphatic cyclic compound having at least one secondary amine nitrogen contained within the ring. Such compounds include, for example, pyrrole, imidazole, pyrazole, 3-pyrroline, and pyrrolidine.

[0097] Guanidines are compounds derived from guanidine, i.e., compounds containing the -NHCNHNH- group, such as, but not limited to, diphenylguanidine, diphenylguanidine acetate, aminobutylguanidine, biguanidine, isopentylguanidine, di-σ-tolylguanidine, o-tolylbiguanide, and triphenylguanidine.

[0098] Other compounds that decompose in situ at temperatures between 40°C and 330°C to produce either primary or secondary amines include, but are not limited to, di- or poly-substituted ureas (e.g., 1,3-dimethylurea); N-alkyl or -dialkylcarbamates (e.g., N-(tert-butyloxycarbonyl)propylamine); di- or poly-substituted thioureas (e.g., 1,3-dimethyl-thiourea); aldehyde-amine condensation products (e.g., 1,3,5-trimethylhexahydro-1,3,5-triazine); N,N'-dialkylphthalamide derivatives (e.g., N,N'-dimethylphthalamide); and amino acids.

[0099] When a thermally activated electron donor precursor compound is utilized as described immediately above, the composition is typically heated before and / or during curing.

[0100] Another type of amine electron donor is represented by the formula: [ka] and [ka] Bis(aminophenols) and bis(aminothiophenols) of the formula: [ka] In the formula, A is SO, O, CO, alkyl having 1 to 6 carbon atoms, perfluoroalkyl having 1 to 10 carbon atoms, or a carbon-carbon bond connecting two aromatic rings. The amino group and hydroxyl group in the formula above are interchangeably located at the meta and para positions relative to the A group.

[0101] In some embodiments, the amine electron donor compound is an aziridine compound. In some embodiments, the aziridine compound comprises at least two aziridine groups. The aziridine compound may comprise 3, 4, 5, 6, or more than 6 aziridine groups. The aziridine compound has the following structure: [ka] wherein R is a core moiety having a valence of Y; L is a bond, a divalent atom, or a divalent linking group; R1, R2, R3, and R4 are independently hydrogen or C1-C4 alkyl (e.g., methyl); Y is typically 2, 3, or more.

[0102] In some embodiments, R is -SO2-. In some embodiments, R is a residue of a multi(meth)acrylate compound. In some embodiments, L is a C1-C4 alkylene optionally substituted with one or more (e.g., adjacent or pendant) oxygen atoms, thereby forming an ether or ester bond. In an exemplary embodiment, R1 is methyl and R2, R3, and R4 are hydrogen.

[0103] Representative aziridine compounds include trimethylolpropane tri-[β-(N-aziridinyl)-propionate, 2,2-bishydroxymethylbutanol tris[3-(1-aziridine)propionate]; 1-(aziridin-2-yl)-2-oxabut-3-ene; and 4-(aziridin-2-yl)-but-1-ene; and 5-(aziridin-2-yl)-pent-1-ene.

[0104] In some embodiments, polyaziridine compounds can be prepared by reacting divinyl sulfone with alkylene (e.g., ethylene) imines, as described in U.S. Patent No. 3,235,544 (Christena). A representative compound is di(2-propyleneiminoethyl) sulfone, shown below: [ka]

[0105] The polyaziridine compounds described above contain at least two aziridine groups when the compounds are added to the coating composition. In other embodiments, the polyaziridine compounds do not contain two aziridine groups when the compounds are added to the composition, and further form polyaziridines in situ. For example, a compound containing a single aziridine group and a single (meth)acrylate group can form a dimer or oligomerize by reaction of the (meth)acrylate groups, thereby forming a polyazirdine (i.e., diaziridine) compound.

[0106] In some embodiments, the composition comprises an electron donor compound comprising at least one (e.g., primary, secondary, tertiary) amine group and at least one organosilane (e.g., alkoxysilane) group. Such compounds can improve the bonding that independently crosslinks the fluoroelastomers described herein, thereby providing a second fluoropolymer crosslinking mechanism. By using an ethylenically unsaturated curing agent in combination with an amino-substituted organosilane, lower concentrations of curing agent and electron donor compound can be utilized to provide a highly crosslinked fluoropolymer.

[0107] In some embodiments, the amine can be characterized as an amino-substituted organosilane ester or ester equivalent having at least one, and preferably two or three, ester or ester equivalent groups on the silicon atom. Ester equivalents are well known to those skilled in the art and include, for example, compounds such as silane amides (RNR'Si), silane alkanoates (RC(O)OSi), Si-O-Si, SiN(R)-Si, SiSR, and RCONR'Si compounds that can be thermally and / or catalytically displaced by R"OH. R and R' are independently selected and can include hydrogen, alkyl, arylalkyl, alkenyl, alkynyl, cycloalkyl, and substituted analogs such as alkoxyalkyl, aminoalkyl, and alkylaminoalkyl. R" can be the same as R and R', except that R" is not H. These ester equivalents can also be cyclic compounds, such as those derived from ethylene glycol, ethanolamine, ethylenediamine (e.g., N-[3-(trimethoxysilyl)propyl]ethylenediamine), and their amides.

[0108] Examples of such cyclic compounds of alternative ester equivalents include: [ka]

[0109] In this example of a cyclic compound, R' is as defined above, but may not be aryl. 3-Aminopropylalkoxysilanes are known to cyclize upon heating, and these RNHSi compounds may be useful in the present invention. Preferably, the amino-substituted organosilane ester or ester equivalent has an ester group, such as methoxy, which is readily volatilized as methanol. The amino-substituted organosilane must have at least one ester equivalent and may be, for example, a trialkoxysilane.

[0110] For example, amino-substituted organosilanes can be represented by the formula (Z2N-L-SiX'X''X''') [wherein, Z is hydrogen, alkyl, or substituted aryl or alkyl, such as amino-substituted alkyl; L may be a divalent linear C1-12 alkylene or may comprise a C3-8 cycloalkylene, a 3-8 membered heterocycloalkylene, a C2-12 alkenylene, a C4-8 cycloalkenylene, a 3-8 membered heterocycloalkenylene, or a heteroarylene unit; and each of X', X" and X"' is a C1-18 alkyl, halogen, C1-8 alkoxy, C1-8 alkylcarbonyloxy, or amino group, with the proviso that at least one of X', X", and X'" is a labile group. Furthermore, any two or all of X', X" and X"' may be linked via a covalent bond. The amino group may be an alkylamino group.

[0111] L may be a divalent aromatic group or may be interrupted by one or more divalent aromatic or heteroatom groups. The aromatic group may include a heteroaromatic group. The heteroatom is preferably nitrogen, sulfur, or oxygen. L is optionally substituted with C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl, C1-4 alkoxy, amino, C3-6 cycloalkyl, 3- to 6-membered heterocycloalkyl, monocyclic aryl, 5- to 6-membered heteroaryl, C1-4 alkylcarbonyloxy, C1-4 alkyloxycarbonyl, C1-4 alkylcarbonyl, formyl, C1-4 alkylcarbonylamino, or C1-4 aminocarbonyl. L is further optionally interrupted by -O-, -S-, -N(Rc)-, -N(Rc)-C(O)-, -N(Rc)-C(O)-O-, -OC(O)-N(Rc)-, -N(Rc)-C(O)-N(Rd)-, -OC(O)-, -C(O)-O-, or -OC(O)-O-. Each of Rc and Rd is independently hydrogen, alkyl, alkenyl, alkynyl, alkoxyalkyl, aminoalkyl (primary, secondary, or tertiary), or haloalkyl.

[0112] Examples of amino-substituted organosilanes include 3-aminopropyltrimethoxysilane (SILQUEST A-1110), 3-aminopropyltriethoxysilane (SILQUEST A-1100), bis(3-trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)n-methylamine, 3-(2-aminoethyl)aminopropyltrimethoxysilane (SILQUEST A-1120), SILQUEST A-1130, (aminoethylaminomethyl)phenethyltrimethoxysilane, (aminoethylaminomethyl)phenethyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (SILQUEST A-2120), bis-(γ-triethoxysilylpropyl)amine (SILQUEST A-2120), and bis-(γ-triethoxysilylpropyl)amine (SILQUEST A-2120). A-1170), N-(2-aminoethyl)-3-aminopropyltributoxysilane, 6-(aminohexylaminopropyl)trimethoxysilane, 4-aminobutyltrimethoxysilane, 4-aminobutyltriethoxysilane, p-(2-aminoethyl)phenyltrimethoxysilane, 3-aminopropyltris(methoxyethoxyethoxy)silane, 3-aminopropylmethyldiethoxysilane, oligomeric aminosilanes such as DYNASYLAN 1146, and 3-(N-methylamino)propyltrimethoxysilane. , N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropyldimethylethoxysilane, and the following cyclic compounds. [ka] [ka] [ka] [ka]

[0113] Bis-silyl urea [RO)3Si(CH2)NR]2C=O is another example of an amino-substituted organosilane ester or ester equivalent.

[0114] In some embodiments, the curing agent may include an amino group with latent functionality. One example of such a curing agent is a blocked amine group such as: R 3 -N=C(R 1 )(R 2 ) [In the formula, R 1 and R 2 are independently selected from linear or branched alkyl groups containing 1 to 6 carbon atoms. In an exemplary embodiment, R is methyl and R 2 R is a straight or branched alkyl group containing at least 2, 3, 4, 5, or 6 carbon atoms. 3 is typically an organic group (e.g., having a molecular weight of less than 500, 450, 400, 350, 300, or 250 g / mol).

[0115] The blocked amine can be activated by water adsorbed on the surface of the coated substrate or by moisture provided by humidity. Unblocking begins in minutes and is generally complete within a few hours (e.g., 2 hours). During unblocking, -N=C(R 1 )(R 2 ) group can be converted to -NH2 and then reacted with (e.g., nitrile cure sites) of the fluoropolymer.

[0116] In some embodiments, the curing agent comprises a blocked amine group and an alkoxysilane group. Such blocked amine curing agents have the following general formula: (R 4 O)3-Si-(CH2) m -N=C(R1)(R2) [In the formula, R 1 and R 2 R is, as described above, independently selected from linear or branched alkyl groups containing 1 to 6 carbon atoms. 1 is independently selected from linear or branched alkyl groups containing 1 to 6 carbon atoms, m is an integer from 1 to 4, and each R 4 are independently a C1 or C2 alkyl group.

[0117] One exemplary curing agent containing blocked amine and alkoxysilane groups is N-(1,3-dimethylbutylidene)aminopropyl-triethoxysilane, shown below: [ka]

[0118] Such curing agents are available from Gelest and from 3M as "3M™ Dynamer™ Rubber Curative RC5125." Blocked amines are additional examples of electron donor precursors.

[0119] In some embodiments, the amine curing agent comprises an aziridine group and an alkoxysilane group. Such compounds are known, for example, from U.S. Pat. No. 3,243,429, which is incorporated herein by reference. Aziridine alkoxysilane compounds have the general structure: [ka] wherein R″ is hydrogen or C1-C4 alkyl (e.g., methyl); X is a bond, a divalent atom, or a divalent linking group; n is 0, 1, or 2; m is 1, 2, or 3; The sum or n+m is 3.

[0120] One representative compound is 3-(2-methylaziridinyl)ethylcarboxylpropyltriethoxysilane.

[0121] Various other suitable aziridine crosslinkers are known and are described in WO 2014 / 075246, published May 22, 2014, and in "NEW GENERATION OF MULTIFUNCTIONAL CROSSLINKERS" (see https: / / www.pstc.org / files / public / Milker00.pdf), which are incorporated herein by reference.

[0122] The composition may include a single (eg, amine) electron donor compound, or a combination of amine electron donor compounds may be present.

[0123] The amount of (e.g., amine) electron donor compound is typically at least 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, or 0.5 wt. % solids (i.e., excluding solvent of the coating composition). In some embodiments, the amount of (e.g., amine) electron donor compound is no more than 5, 4.5, 4, 3.5, or 3 wt. % solids.

[0124] In some embodiments, the fluoropolymer composition further comprises an alkoxysilane compound that does not have an amine functionality. In some embodiments, such an alkoxysilane has the formula: R 2 Si(OR 1 ) m [In the formula, R 1 are independently alkyl as defined above, R 2 are independently hydrogen, alkyl, aryl, alkaryl, or OR 1 and m ranges from 1 to 3, and as noted above is typically 2 or 3.

[0125] formula R 2 Si(OR 1 ) m Suitable alkoxysilanes include, but are not limited to, tetra-, tri-, or dialkoxysilanes, and any combinations or mixtures thereof. Representative alkoxysilanes include propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane.

[0126] Preferably, the alkyl group of the alkoxysilane contains 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms. Preferred alkoxysilanes for use herein are selected from the group consisting of tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and any mixture thereof. Preferred alkoxysilanes for use herein include tetraethoxysilane (TEOS). The alkoxysilanes without organofunctional groups utilized in the method of making the coating composition may be partially hydrolyzed, such as in the case of partially hydrolyzed tetramethoxysilane (TMOS) available from Mitsuibishi Chemical Company under the trade designation "MS-51."

[0127] When present, the amount of alkoxysilane compound without (amine / electron donor) functionality (e.g., TESO) is typically at least 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, or 0.5 wt. % solids (i.e., excluding solvents of the coating composition). In some embodiments, the amount of alkoxysilane compound without functional groups is no more than 5, 4.5, 4, 3.5, or 3 wt. % solids.

[0128] In some embodiments, the compositions described herein comprise a (e.g., UV) cure system comprising an ethylenically unsaturated compound in combination with an electron donor compound, such as an amine, in the absence of an organic peroxide. The organic peroxide is an electron acceptor and therefore competes with ionized halogen atoms, thereby reducing crosslinking of the fluoropolymer. In some embodiments, the composition is also substantially free of other electron acceptors that reduce crosslinking.

[0129] In other embodiments, aminoorganosilane ester compounds or ester equivalents can be utilized in the absence of ethylenically unsaturated compounds capable of (e.g., UV) curing and / or thermal curing the fluoropolymer, as described in International Application No. PCT / US2019 / 036460, which is incorporated herein by reference.

[0130] The fluoropolymer (coating solution) composition includes at least one solvent. The solvent is capable of dissolving the fluoropolymer. The solvent is typically present in an amount of at least about 25% by weight, based on the total weight of the coating solution composition. In some embodiments, the solvent is present in an amount of at least 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95%, or more, based on the total weight of the coating solution composition.

[0131] The fluoropolymer (coating solution) composition typically comprises at least 0.01, 0.02, 0.03, 0.03, 0.04, 0.04, 0.05, 0.06, 0.7, 0.8, 0.9, or 1 wt.% fluoropolymer based on the weight of the total coating solution composition. In some embodiments, the fluoropolymer coating solution composition comprises at least 2, 3, 4, or 5 wt.% fluoropolymer. In some embodiments, the fluoropolymer coating solution composition comprises at least 6, 7, 8, 9, or 10 wt.% fluoropolymer. The fluoropolymer coating solution composition typically comprises no more than 50, 45, 40, 35, 30, 25, or 20 wt.% fluoropolymer based on the weight of the total coating solution composition.

[0132] The optimal amount of solvent and fluoropolymer may vary depending on the end use. For example, to provide a thin coating, a very dilute fluoropolymer solution in the solvent, e.g., 0.01% to 5% by weight of fluoropolymer, may be desired. Also, for spray coating applications, a low viscosity composition may be preferable to a high viscosity solution. The concentration of fluoropolymer in the solution affects the viscosity and can be adjusted accordingly. An advantage of the present disclosure is that solutions can also be prepared that contain a high concentration of fluoropolymer yet still result in a low viscosity, clear liquid composition.

[0133] In some embodiments, the fluoropolymer coating solution composition can be a liquid. The liquid can have, for example, a viscosity of less than 2,000 mPas at room temperature (20°C + / - 2°C). In other embodiments, the fluoropolymer coating solution composition is a paste. The paste can have, for example, a viscosity of 2,000 to 100,000 mPas at room temperature (20°C + / - 2°C).

[0134] The solvent is liquid at ambient conditions and typically has a boiling point above 50° C. Preferably, the solvent has a boiling point below 200° C. so that it can be easily removed. In some embodiments, the solvent has a boiling point below 190, 180, 170, 160, 150, 140, 130, 120, 110, or 100° C.

[0135] The solvent is partially or fully fluorinated. Therefore, the solvent is non-aqueous. Various partially or fully fluorinated solvents are known, including perfluorocarbons (PFCs), hydrochlorofluorocarbons (HCFCs), perfluoropolyethers (PFPEs), and hydrofluorocarbons (HFCs), as well as fluorinated ketones and fluorinated alkylamines.

[0136] In some embodiments, the solvent has a global warming potential (GWP, 100-year ITH) of less than 1000, 900, 800, 700, 600, 500, 400, 300, 200, or 100. The GWP is typically greater than 0 and can be at least 10, 20, 30, 40, 50, 60, 70, or 80.

[0137] As used herein, GWP is a relative measure of the global warming potential of a compound based on the structure of the compound. The GWP of a compound, as defined by the Intergovernmental Panel on Climate Change (IPCC) in 1990 and revised in subsequent reports, is calculated as the warming caused by the release of 1 kilogram of the compound relative to the warming caused by the release of 1 kilogram of CO2 over a specific integration time horizon (ITH).

number

[0138] In some embodiments, the solvent comprises a partially fluorinated ether or partially fluorinated polyether. The partially fluorinated ether or polyether may be linear, cyclic, or branched. Preferably, it is branched. Preferably, the partially fluorinated ether or polyether comprises a non-fluorinated alkyl group and a fully fluorinated alkyl group, and more preferably, the fully fluorinated alkyl group is branched.

[0139] In one embodiment, the partially fluorinated ether or polyether solvent has the formula: Rf-OR where Rf is a perfluorinated or partially fluorinated alkyl or (poly)ether group, and R is a non-fluorinated or partially fluorinated alkyl group. Typically, Rf can have 1 to 12 carbon atoms. Rf may be a primary, secondary, or tertiary fluorinated or perfluorinated alkyl residue. This means that when Rf is a primary alkyl residue, the carbon atom linked to the ether atom contains two fluorine atoms and is bonded to another carbon atom of the fluorinated or perfluorinated alkyl chain. In that case, Rf is R f 1 This polyether corresponds to —CF— and has the general formula: R f 1 It can be represented as -CF2-OR.

[0140] When Rf is a secondary alkyl residue, the carbon atom linked to the ether atom is also linked to one fluorine atom and two carbon atoms of the partially and / or fully fluorinated alkyl chain, and Rf is (R f 2 R f 3 )CF-. This polyether corresponds to (R f 2 Rf 3 )CF-OR.

[0141] When Rf is a tertiary alkyl residue, the carbon atom linked to the ether atom is also linked to three carbon atoms of the partially and / or fully fluorinated alkyl chain, and Rf is (R f 4 R f 5 R f 6 )-C-. This polyether corresponds to (R f 4 R f 5 R f 6 )-C-OR. R f 1 , R f 2 , R f 3 , R f 4 , R f 5 , R f 6 corresponds to the definition of Rf and is a perfluorinated or partially fluorinated alkyl group, optionally interrupted by one or more ether oxygens. They may be linear, branched, or cyclic. Polyether combinations may also be used, as may combinations of primary, secondary, and / or tertiary alkyl residues.

[0142] An example of a solvent containing a partially fluorinated alkyl group is C3F7OCHFCF3 (CAS number 3330-15-2).

[0143] An example of a solvent where Rf comprises a perfluorinated (poly)ether is C3F7OCF(CF3)CF2OCHFCF3 (CAS number 3330-14-1).

[0144] In some embodiments, the partially fluorinated ether solvent has the formula: CpF2p+1-O-CqH2q+1 [wherein q is an integer of 1 to 5, for example, 1, 2, 3, 4, or 5, and p is an integer of 5 to 11, for example, 5, 6, 7, 8, 9, 10, or 11]. Preferably, C p F 2p+1 is branched. Preferably, C p F 2p+1 is branched and q is 1, 2 or 3.

[0145] Representative solvents include, for example, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane and 3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-(trifluoromethyl)hexane, which are commercially available, for example, from 3M Company (St. Paul, MN) under the trade name NOVEC.

[0146] Fluorinated (e.g., ether and polyether) solvents may be used alone or in combination with other solvents, which may be fluorochemical or non-fluorochemical solvents. When a non-fluorochemical solvent is combined with a fluorinated solvent, the concentration of the non-fluorochemical solvent is typically less than 30, 25, 20, 15, 10, or 5 wt. % based on the total amount of solvent. Representative non-fluorochemical solvents include ketones such as acetone, MEK, methyl isobutyl ketone, methyl amyl ketone, and NMP; ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tetrahydrofurfuryl ether; esters such as methyl acetate, ethyl acetate, and butyl acetate; and cyclic esters such as delta-valerolactone and gamma-valerolactone.

[0147] In some embodiments, the composition further comprises crystalline fluoropolymer particles.

[0148] In one embodiment, such coating compositions are prepared by blending a latex containing crystalline fluoropolymer particles with a latex containing amorphous fluoropolymer particles. The fluoropolymer particles typically have a small average particle size, e.g., less than 400 nm, but can be larger, especially if the applied coating is rubbed after curing. For example, the fluoropolymer particle size range can be from about 50 to about 1000 nm, or from about 50 to about 400 nm, or from about 50 to about 200 nm.

[0149] The latexes can be combined in any suitable manner, such as by vortex mixing for 1-2 minutes. The method further includes coagulating the mixture of latex particles. Coagulation can be carried out, for example, by cooling (e.g., freezing) the blended latex or by adding a suitable salt (e.g., magnesium chloride). Cooling is particularly desirable for coatings used in semiconductor manufacturing and other applications where the introduction of salts may be undesirable. The method optionally further includes washing the coagulated mixture of amorphous and crystalline fluoropolymer particles. The washing step can substantially remove emulsifiers or other surfactants from the mixture and can help obtain a well-mixed blend of substantially non-agglomerated dry particles. In some embodiments, the surfactant level in the resulting dry particle mixture can be, for example, less than 0.1 wt.%, less than 0.05 wt.%, or less than 0.01 wt.%. The method further includes drying the coagulated latex mixture. The coagulated latex mixture can be dried by any suitable means, such as air drying or oven drying. In one embodiment, the coagulated latex mixture can be dried at 100° C. for 1 to 2 hours.

[0150] The dried coagulated latex mixture can be dissolved in a solvent suitable for dissolving the amorphous fluoropolymer particles to form a stable coating composition containing a homogeneous dispersion of crystalline fluoropolymer particles in a solution of amorphous fluoropolymer.

[0151] The coating solution can be utilized to provide a coating on a substrate by applying a layer of the coating composition to the surface of the substrate and drying the coating composition (i.e., removing the fluorinated solvent by evaporation).

[0152] In some embodiments, the method further comprises scrubbing (eg, buffing, polishing) the dried layer, thereby forming an amorphous fluoropolymer binder layer containing crystalline submicron fluoropolymer particles.

[0153] The submicron crystalline fluoropolymer particles at the coating surface form a thin, continuous or nearly continuous fluoropolymer surface layer disposed on the underlying coating of amorphous fluoropolymer. In a preferred embodiment, the thin crystalline fluoropolymer layer is spread relatively uniformly on the underlying coating and appears thinner and more uniform than if the fluoropolymer particles were simply subjected to fibrillation (e.g., by orientation or other stretching).

[0154] The average roughness (Ra) of a surface is the arithmetic mean of the absolute values ​​of the surface height deviations measured from the mean plane. In some embodiments, Ra is at least 40 or 50 nm and up to 100 nm before rubbing. In some embodiments, the surface after rubbing is at least 10, 20, 30, 40, 50, or 60% smoother. In some embodiments, Ra is less than 35, 30, 25, or 20 nm after rubbing.

[0155] Various rubbing techniques can be used when forming the coating or when the coated article is or will be used thereafter. Simply wiping or buffing the coating several times with cheesecloth or other suitable woven, nonwoven, or knitted fabric is often sufficient to form the desired thin layer. Those skilled in the art will understand that many other rubbing techniques can be used. Rubbing can also reduce the haze of the cured coating.

[0156] Various crystalline fluoropolymer particles can be used, including mixtures of different crystalline fluoropolymer particles.Crystalline fluoropolymer particles typically have high crystallinity, and therefore have significant melting point (peak maximum) as determined by differential scanning calorimetry according to DIN EN ISO 11357-3:2013-04 under nitrogen flow and a heating rate of 10 ° C. / min.

[0157] For example, the crystalline fluoropolymer particles may comprise particles of a fluoropolymer having a Tm of at least 100, 110, 120, or 130° C. In some embodiments, the crystalline fluoropolymer particles may comprise particles of a fluoropolymer having a Tm of 350, 340, 330, 320, 310, or 300° C. or less.

[0158] The crystalline fluoropolymer particles typically have a fluorine content greater than about 50 weight percent, and may include particles of fluoropolymer having a fluorine content of about 50 to about 76 weight percent, about 60 to about 76 weight percent, or about 65 to about 76 weight percent.

[0159] Representative crystalline fluoropolymers include, for example, 3M™ Dyneon™ PTFE Dispersions TF5032Z, TF5033Z, TF5035Z, TF5050Z, TF5135GZ, and TF5070GZ; and perfluorinated fluoropolymers such as 3M™ Dyneon™ Fluorothermoplastic Dispersions PFA6900GZ, PFA6910GZ, FEP6300GZ, and THV340Z.

[0160] Other suitable fluoropolymer particles are available from suppliers such as Asahi Glass, Solvay Solexis, and Daikin Industries, and are known to those skilled in the art.

[0161] Commercially available aqueous dispersions typically contain nonionic and / or ionic surfactants at concentrations up to 5-10% by weight. These surfactants are substantially removed by washing the coagulated blend. Residual surfactant concentrations of less than 1, 0.05, or 0.01% by weight may be present. Because the nonionic / ionic surfactant content is not as high, it is often more convenient to use an "as-polymerized" aqueous fluoropolymer latex.

[0162] As mentioned above, crystalline fluoropolymers have a melting point that can be determined by DSC. The degree of crystallinity depends on the selection and concentration of polymerized monomers in the fluoropolymer. For example, PTFE homopolymer (containing 100% TFE units) has a melting point (Tm) above 340°C. The addition of a comonomer, such as an unsaturated (per)fluoroalkyl ether, reduces the Tm. For example, if a fluoropolymer contains about 3-5 wt% polymerized units of such a comonomer, the Tm is about 310°C. As yet another example, if a fluoropolymer contains about 15-20 wt% polymerized units of HFP, the Tm is about 260-270°C. As yet another example, if a fluoropolymer contains 30 wt% polymerized units of a (per)fluoroalkyl ether (e.g., PMVE) or other comonomer that reduces crystallinity, the fluoropolymer no longer has a melting point detectable via DSC and is therefore characterized as amorphous.

[0163] In some embodiments, crystalline fluoropolymer particles contain at least 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or about 100% by weight of polymerized units of TFE.In addition, crystalline fluoropolymer particles typically contain a lower concentration of unsaturated (per)fluoroalkyl ether (e.g., PMVE) than amorphous fluoropolymer.In typical embodiments, crystalline fluoropolymer particles contain less than 30, 25, 20, 15, 10, or 5% by weight of polymerized units of (per)fluoroalkyl ether (e.g., PMVE).

[0164] In some embodiments, the crystalline fluoropolymer is a copolymer formed from constituent monomers known as tetrafluoroethylene ("TFE"), hexafluoropropylene ("HFP"), and vinylidene fluoride ("VDF", "VF2"). The monomer structures of these constituents are shown below: TFE:CF2=CF2(1) VDF:CH2=CF2(2) HFP:CF2=CF-CF3(3)

[0165] In some embodiments, the crystalline fluoropolymer is comprised of at least two constituent monomers (HFP and VDF), and in some embodiments, all three constituent monomers, in various molar amounts.

[0166] Tm depends on the amount of TFE, HFP, and VDF. For example, a fluoropolymer containing about 45% by weight of polymerized units of TFE, about 18% by weight of polymerized units of HFP, and about 37% by weight of polymerized units of VDF has a Tm of about 120 ° C. As another example, a fluoropolymer containing about 76% by weight of polymerized units of TFE, about 11% by weight of polymerized units of HFP, and about 13% by weight of polymerized units of VDF has a Tm of about 240 ° C. By increasing the polymerized units of HFP / VDF, while decreasing the polymerized units of TFE, the fluoropolymer becomes amorphous. An overview of crystalline and amorphous fluoropolymers can be found in Ullmann's Encyclopedia of Industrial Chemistry (7th Edition, 2013 Wiley-VCH Verlag. 10.1002 / 14356007.a11 393 pub 2), Chapter: Fluoropolymers, Organic.

[0167] The crystalline fluoropolymer particles and amorphous fluoropolymer particles can be combined in various ratios. For example, the coating composition contains about 5 to about 95 weight percent crystalline fluoropolymer particles and about 95 to about 5 weight percent amorphous fluoropolymer, based on the total weight percent solids (i.e., excluding solvent). In some embodiments, the coating composition contains about 10 to about 75 weight percent crystalline fluoropolymer particles and about 90 to about 25 weight percent amorphous fluoropolymer.

[0168] In some embodiments, the coating composition contains from about 10 to about 50 weight percent crystalline fluoropolymer particles and from about 90 to about 50 weight percent amorphous fluoropolymer, hi some embodiments, the coating composition contains from about 10 to about 30 weight percent crystalline fluoropolymer particles and from about 90 to about 70 weight percent amorphous fluoropolymer.

[0169] Compositions containing curable fluoroelastomers may further contain additives known in the art. Examples include acid acceptors. Such acid acceptors can be inorganic or blends of inorganic and organic acid acceptors. Examples of inorganic acceptors include magnesium oxide, lead oxide, calcium oxide, calcium hydroxide, dibasic lead phosphate, zinc oxide, barium carbonate, strontium hydroxide, calcium carbonate, and hydrotalcite. Organic acceptors include epoxy, sodium stearate, and magnesium oxalate. Particularly suitable acid acceptors include magnesium oxide and zinc oxide. Blends of acid acceptors can also be used. The amount of acid acceptor generally depends on the nature of the acid acceptor used. Typically, the amount of acid acceptor used is 0.5 to 5 parts per 100 parts of fluoropolymer.

[0170] The fluoropolymer composition may contain additional additives typically utilized in the processing and compounding of fluoropolymers, such as stabilizers, surfactants, ultraviolet ("UV") absorbers, antioxidants, plasticizers, lubricants, fillers, and processing aids, provided that they have sufficient stability under the intended conditions of use. Specific examples of additives include carbon particles such as carbon black, graphite, and soot. Additional additives include, but are not limited to, pigments, such as iron oxide and titanium dioxide. Other additives include, but are not limited to, clay, silicon dioxide, barium sulfate, silica, glass fiber, or other additives known and used in the art.

[0171] In some embodiments, the fluoropolymer composition includes silica, glass fiber, thermally conductive particles, or a combination thereof. Any amount of silica and / or glass fiber and / or thermally conductive particles can be present. In some embodiments, the amount of silica and / or glass fiber is at least 0.05, 0.1, 0.2, or 0.3 wt.% of the total solids of the composition. In some embodiments, the amount of silica and / or glass fiber is no more than 5, 4, 3, 2, or 1 wt.% of the total solids of the composition. Small concentrations of silica can be utilized to thicken the coating composition. Additionally, small concentrations of glass fiber can be used to improve the strength of the fluoropolymer film. In other embodiments, the amount of glass fiber can be at least 5, 10, 15, 20, 25, 35, 40, 45, or 50 wt.% of the total solids of the composition. The amount of glass fiber is typically no more than 55, 50, 45, 40, 35, 25, 20, 15, or 10 wt.%. In some embodiments, the glass fibers have an average length of at least 100, 150, 200, 250, 300, 350, 400, 450, or 500 microns. In some embodiments, the glass fibers have an average length of at least 1, 2, or 3 mm, and typically no more than 5 or 10 mm. In some embodiments, the glass fibers have an average diameter of at least 1, 2, 3, 4, or 5 microns, and typically no more than 10, 15, 30, or 25 microns. The glass fibers may have an aspect ratio of at least 3:1, 5:1, 10:1, or 15:1.

[0172] In some embodiments, the fluoropolymer composition does not contain inorganic oxide particles (e.g., silica). In other embodiments, the fluoropolymer composition contains inorganic oxide particles (e.g., silica and / or thermally conductive). In some embodiments, the amount of inorganic oxide particles (e.g., silica and / or thermally conductive) is at least 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt. % of the total solids of the composition. In some embodiments, the amount of inorganic oxide particles (e.g., silica and / or thermally conductive) is no more than 90, 85, 80, 75, 70, or 65 wt. % of the total solids of the composition. Various combinations of silica and thermally conductive particles can be utilized. In some embodiments, the total amount of inorganic oxide particles (e.g., silica and thermally conductive), or the amount of specific types of silica particles (e.g., fused silica, fumed silica, glass bubbles, etc.) or thermally conductive particles (e.g., boron nitride, silicon carbide, aluminum oxide, aluminum trihydrate) is 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5 wt.% or less of the total solids of the composition. To further reduce dielectric properties, a higher concentration of inorganic oxide particles (e.g., silica) may be preferred. Thus, compositions containing inorganic oxide particles (e.g., silica) may have even lower dielectric properties than crosslinked fluoropolymer alone.

[0173] In some embodiments, the inorganic oxide particles (e.g., silica) and / or glass fibers have a dielectric constant at 1 GHz of less than or equal to 7, 6.5, 6, 5.5, 5, 4.5, or 4. In some embodiments, the inorganic oxide particles (e.g., silica) and / or glass fibers have a dielectric loss tangent at 1 GHz of less than or equal to 0.005, 004, 0.003, 0.002, or 0.0015.

[0174] In some embodiments, the composition comprises inorganic oxide particles or glass fibers comprising primarily silica. In some embodiments, the amount of silica is typically at least 50, 60, 70, 75, 80, 85, or 90 wt. % of the inorganic oxide particles or glass fibers, and in some embodiments, the amount of silica is typically at least 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or more (e.g., at least 99.5, 99.6, or 99.7) wt. % silica. Higher silica concentrations typically have lower dielectric constants. In some embodiments, the (e.g., fused) silica particles may further comprise small concentrations of other metals / meta oxides, such as Al2O3, Fe2O5, TiO2, KO, CaO, MgO, and Na2O. In some embodiments, the total amount of such metals / metal oxides (e.g., Al2O3, CaO, and MgO) is independently 30, 25, 20, 15, or 10 wt.% or less. In some embodiments, the inorganic oxide particles or glass fibers may include B2O3. The amount of B2O3 may range up to 25 wt.% of the inorganic oxide particles or glass fibers. In other embodiments, (e.g., fumed) silica particles may further include small concentrations of additional metal / metal oxides such as Cr, Cu, Li, Mg, Ni, P, and Zr. In some embodiments, the total amount of such metals or metal oxides is 5, 4, 3, 2, or 1 wt.% or less. In some embodiments, silica may be described as quartz. The amount of non-silica metal or metal oxides can be determined by the use of inductively coupled plasma mass spectrometry. Inorganic oxide particles (e.g., silica) are typically dissolved in hydrofluoric acid and distilled at low temperatures as H2SiF6.

[0175] In some embodiments, inorganic particles may be characterized as "agglomerates," meaning weak associations between primary particles, such as particles held together by charge or polarity. Agglomerates are typically physically broken down into smaller entities, such as primary particles, during preparation of the coating solution. In other embodiments, inorganic particles may be characterized as "aggregates," meaning strongly bonded or fused particles, such as covalently or thermally bonded particles prepared by processes such as sintering, electric arc, flame hydrolysis, or plasma. Aggregates are typically not physically broken down into smaller entities, such as primary particles, during preparation of the coating solution. "Primary particle size" refers to the average diameter of a single (unaggregated, non-agglomerated) particle.

[0176] The (e.g., silica) particles can have a variety of shapes, such as spherical, ellipsoidal, linear, or branched. Fused and fumed silica aggregates are more commonly branched. The aggregate size is generally at least 10 times the primary particle size of the individual parts.

[0177] In other embodiments, the (e.g., silica) particles may be characterized as glass bubbles. The glass bubbles may be prepared from soda-lime borosilicate glass. In this embodiment, the glass may contain approximately 70 percent silica (silicon dioxide), 15 percent soda (sodium oxide), and 9 percent lime (calcium oxide), along with smaller amounts of various other compounds.

[0178] In some embodiments, the inorganic oxide particles can be characterized as (e.g., silica) nanoparticles having an average or median particle size of less than 1 micron. In some embodiments, the average or median particle size of the (e.g., silica) inorganic oxide particles is 500 or 750 nm. In other embodiments, the average particle size of the (e.g., silica) inorganic oxide particles can be at least 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10 microns. In some embodiments, the average particle size is 30, 25, 20, 15, or 10 microns or less. In some embodiments, the composition contains little or no (e.g., colloidal silica) nanoparticles having particles of 100 nanometers or less. The concentration of (e.g., colloidal silica) nanoparticles is typically less than (10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 wt. %. Inorganic oxides (eg, silica particles) can include a normal distribution of particle sizes with a single peak, or a distribution of particles with two or more peaks.

[0179] In some embodiments, 1% or less by weight of the inorganic oxide (e.g., silica) particles have a particle size of 3 or 4 microns or greater. In some embodiments, 1% or less by weight of the inorganic oxide (e.g., silica) particles have a particle size of 5 or 10 microns or greater. In other embodiments, 5, 4, 3, 2, or 1% or less by weight of the particles have a particle size greater than 45 microns. In some embodiments, 1% or less by weight of the particles have a particle size in the range of 75-150 microns.

[0180] In some embodiments, the average or median particle size refers to the "primary particle size," which refers to the average or median diameter of individual, non-aggregated, non-agglomerated particles. For example, the particle size of colloidal silica or glass bubbles is typically the average or median particle size in preferred embodiments, and the average or median particle size refers to the average or median diameter of the aggregates. The particle size of inorganic particles can be measured using transmission electron microscopy. The particle size of fluoropolymer coating solutions can be measured using dynamic light scattering.

[0181] In some embodiments, the inorganic (eg, silica) particles have a specific gravity in the range of 2.18 to 2.20 g / cc.

[0182] Aggregated particles, such as in the case of fumed and fused (e.g., silica) particles, may have a smaller surface area than primary particles of the same size. In some embodiments, the (e.g., silica) particles have a surface area of ​​about 50-500 m 2 In some embodiments, the BET surface area is in the range of 450, 400, 350, 300, 250, 200, 150, or 100 m / g. 2 / g.

[0183] In some embodiments, the inorganic nanoparticles may be characterized as colloidal silica. It is understood that unmodified colloidal silica nanoparticles generally contain hydroxyl or silanol functional groups on the nanoparticle surface and are typically characterized as hydrophilic.

[0184] In some embodiments, inorganic particles (e.g., silica aggregates), and particularly colloidal silica nanoparticles, are surface-treated with a hydrophobic surface treatment. Common hydrophobic surface treatments include compounds such as alkoxylsilanes (e.g., octadecyltriethoxysilane), silazanes, or siloxanes. Various hydrophobic fumed silicas are commercially available from AEROSIL™, Evonik, and various other suppliers. Exemplary hydrophobic fumed silicas include AEROSIL™ grades R972, R805, RX300, and NX90S.

[0185] In some embodiments, inorganic particles (e.g., silica aggregates) are surface-treated with a fluorinated alkoxysilane compound. Such compounds typically contain a perfluoroalkyl group or a perfluoropolyether group. The perfluoroalkyl group or perfluoropolyether group typically has 4, 5, 6, 7, or 8 carbon atoms or less. The alkoxysilane group can be attached to the alkoxysilane group by a variety of divalent linking groups, including alkylene, urethane, and -SON(Me)-. Some representative fluorinated alkoxysilanes are described in U.S. Pat. No. 5,274,159 and WO 2011 / 043973, which are incorporated herein by reference. Other fluorinated alkoxysilanes are commercially available.

[0186] The fluoropolymer composition can be prepared by mixing a polymer, a curing agent including at least one ethylenically unsaturated curing agent, at least one compound having an electron donating group, optional additives, and a fluorinated solvent. In some embodiments, the fluoropolymer is first dissolved in a fluorinated solvent, and the curing agent and other additives including the electron donor compound are then added.

[0187] In some embodiments, the fluoropolymer composition comprises thermally conductive particles.

[0188] In some embodiments, the thermally conductive inorganic particles are preferably non-electrically conductive. Suitable non-electrically conductive materials include ceramics such as metal oxides, hydroxides, oxyhydroxides, silicates, borides, carbides, and nitrides. Suitable ceramic fillers include, for example, silicon oxide, zinc oxide, alumina trihydrate (ATH) (also known as hydrated alumina, aluminum oxide, and aluminum trihydroxide), aluminum nitride, boron nitride, silicon carbide, and beryllium oxide. Other thermally conductive fillers include carbon-based materials such as graphite and metals such as aluminum and copper. Combinations of different thermally conductive materials can be used. Such materials are not electrically conductive, i.e., have an electronic bandgap greater than 0 eV, and in some embodiments, at least 1, 2, 3, 4, or 5 eV. In some embodiments, such materials have an electronic bandgap of 15 or 20 eV or less. In this embodiment, the composition may optionally further comprise a low concentration of thermally conductive particles having an electronic bandgap less than 0 eV or greater than 20 eV.

[0189] In a preferred embodiment, the thermally conductive particles comprise a material having a bulk thermal conductivity of >10 W / m·K. The thermal conductivities of some representative inorganic materials are listed in the table below. [Table 2]

[0190] In some embodiments, the thermally conductive particles comprise a material having a bulk thermal conductivity of at least 15 or 20 W / m·K. In other embodiments, the thermally conductive particles comprise a material having a bulk thermal conductivity of at least 25 or 30 W / m·K. In still other embodiments, the thermally conductive particles comprise a material having a bulk thermal conductivity of at least 50, 75, or 100 W / m·K. In still other embodiments, the thermally conductive particles comprise a material having a bulk thermal conductivity of at least 150 W / m·K. In typical embodiments, the thermally conductive particles comprise a material having a bulk thermal conductivity of about 350 or 300 W / m·K or less.

[0191] Thermally conductive particles are available in a number of shapes, including spherical and acicular shapes that can be irregular or plate-like. In some embodiments, the thermally conductive particles are crystalline and typically have a geometric shape. For example, hexagonal boron nitride is commercially available from Momentive. Furthermore, alumina trihydrate is described as a hexagonal platelet. A combination of particles having different shapes can be utilized. The thermally conductive particles generally have an aspect ratio of less than 100:1, 75:1, or 50:1. In some embodiments, the thermally conductive particles have an aspect ratio of less than 3:1, 2.5:1, 2:1, or 1.5:1. In some embodiments, generally symmetrical (e.g., spherical, hemispherical) particles can be used.

[0192] Boron nitride particles are commercially available from 3M as "3M™ Boron Nitride Cooling Fillers."

[0193] In some embodiments, the boron nitride particles have a density of at least 0.05, 0.01, 0.15, 0.03 g / cm 3 , up to about 0.60, 0.70, or 0.80 g / cm 3 The surface area of ​​the boron nitride particles is in the range of <25, <20, <10, <5, or <3 m 2 The surface area may be typically at least 1 or 2 m 2 / g.

[0194] In some embodiments, the boron nitride (e.g., platelet) particles have a particle size d(0.1) in the range of about 0.5 to 5 microns. In some embodiments, the boron nitride (e.g., platelet) particles have a particle size d(0.9) in the range of at least 5 and up to 20, 25, 30, 35, 40, 45, or 50 microns.

[0195] The coating compositions described herein that include fluorinated solvents are "stable," meaning that the coating composition remains homogeneous when stored in a sealed container at room temperature for at least 24 hours. In some embodiments, the coating composition is stable for one week or more. "Homogeneous" refers to a coating composition that does not exhibit a visibly separated precipitate or a visibly separated layer when freshly shaken, placed in a 100 mL glass container, and allowed to stand at room temperature for at least four hours.

[0196] In some embodiments, the fluoropolymer is first combined with other solid ingredients, particularly the electron donor (e.g., amine) compound and ethylenically unsaturated curing agent described herein, and inorganic particles (e.g., silica), if present. The fluoropolymer and amine compound can be combined in conventional rubber processing equipment to provide a solid mixture, i.e., a solid polymer containing additional ingredients, also referred to in the art as a "compound." Typical equipment includes rubber mills, internal mixers such as Banbury mixers, and mixing extruders. During mixing, the components and additives are uniformly dispersed throughout the resulting fluoropolymer "compound" or polymer sheet. The compound is then preferably pulverized, for example, by cutting into smaller pieces, and then dissolved in a solvent.

[0197] The fluoropolymer coating solution compositions described herein are suitable for coating substrates. Fluoropolymer coating solution compositions can be formulated to have various viscosities, depending on the solvent and fluoropolymer content and the presence or absence of optional additives. Fluoropolymer coating solution compositions typically contain or are solutions of fluoropolymers, and can be in the form of a liquid or paste. Although the compositions may contain dispersed or suspended materials, these materials are preferably additives and are not fluoropolymers of the type described herein. Preferably, the compositions are liquids, more preferably solutions containing one or more fluoropolymers described herein dissolved in a solvent described herein.

[0198] The fluoropolymer compositions described herein are suitable for coating substrates and the viscosity can be adjusted (via solvent content) to make them applicable by a variety of coating methods, including but not limited to spray coating or printing (such as, but not limited to, ink printing, 3D printing, screen printing), painting, impregnation, roller coating, bar coating, dip coating, and solvent casting.

[0199] Coated substrates and articles can be prepared by applying the fluoropolymer composition to a substrate and removing the solvent. Curing can occur upon, during, or after solvent removal. The solvent can be reduced or completely removed, for example, by evaporation, drying, or by allowing the solvent to evaporate. After solvent removal, the composition can be characterized as "dry."

[0200] The methods for making crosslinked fluoropolymers described herein include curing a fluoropolymer with actinic radiation (e.g., UV or electron beam). The fluoropolymer composition, the substrate, or both are transparent to the curing radiation. In some embodiments, a combination of UV curing and thermal (e.g., post-) curing is utilized. The curing is carried out at a temperature and for a time effective to form a cured fluoroelastomer. Optimization of conditions can be tested by examining the fluoroelastomer for its mechanical and physical properties. Curing can be carried out in an oven with or without pressure. A post-cure cycle at elevated temperature and / or pressure may be applied to ensure complete completion of the curing process. The curing conditions depend on the cure system used.

[0201] In some embodiments, the composition is cured by UV curing. The fluoropolymer of the composition described herein contains little or no polymerized units of vinylidene fluoride (VDF) (i.e., CH₂=CF₂) or VDF bonded to hexafluoropropylene (HFP). Polymerized units of VDF can undergo dehydrofluorination (i.e., HF elimination reaction), as described in U.S. Patent Application Publication No. 2006 / 0147723. The reaction is limited by the number of polymerized VDF groups bonded to the HFP groups contained in the fluoropolymer. The double bonds generated as a result of dehydrofluorination can then react with aminoalkoxysilanes (via Michael addition), thereby grafting fluorinated pendant alkoxysilane groups onto the fluoropolymer backbone. When irradiated with UV light, such pendant groups can undergo free-radical copolymerization with multifunctional (meth)acrylate compounds.

[0202] However, because the fluoropolymer of the composition described herein contains few or no polymerized units of VDF (i.e., CH2=CF2) bonded to HFP groups, the fluoropolymer is not affected by the reaction scheme just described. As evidenced by the following examples, an amine compound alone can initiate UV curing in the absence of a free radical photoinitiator. The inclusion of a free radical photoinitiator typically does not increase the crosslinking of the fluoropolymer. This result suggests that the fluoropolymer is not crosslinked via a free radical mechanism.

[0203] The composition may optionally further comprise a photoinitiator, although a conventional free radical initiator is not required. In other embodiments, the composition is substantially free of free radical initiators, including such free radical photoinitiators.

[0204] In some embodiments, the UV radiation may have sufficient intensity at wavelengths of at least 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, or 240 nm. In some embodiments, the UV radiation may have sufficient intensity at wavelengths of 350 nm, 340 nm, 330 nm, 320 nm, 310 nm, or 290 nm or less. In some embodiments, the (e.g., UV) actinic radiation has sufficient intensity at wavelengths in the range of 270-290 nm so that, in the presence of an electron donor (e.g., an amine), a wavelength-induced single electron transfer reaction can occur between C-I bonds. In some embodiments, the UV radiation has sufficient intensity at wavelengths below 240 nm (150-200 nm) so that, in the presence of an electron donor (e.g., an amine), a wavelength-induced single electron transfer reaction can occur between C-Cl or C-Br bonds.

[0205] UV light sources can be of various types. Low intensity sources such as black lights typically produce 0.1 or 0.5 mW / cm 2 (milliwatts per square centimeter) to 10mW / cm 2(measured by a United States National Institute of Standards and Technology approved dosimeter, e.g., UVIMAP UM 365 LS (Electronic Instrumentation & Technology, Inc., Sterling, VA)). High-intensity sources generally have intensities in the range of 10, 15, or 20 mW / cm. 2 Ultra-high intensity, up to 450mW / cm 2 In some embodiments, the high intensity light source provides an intensity in the range of up to 500, 600, 700, 800, 900, or 1000 mW / cm. 2 UV light for polymerizing the ethylenically unsaturated monomers can be provided by a variety of light sources, including light-emitting diodes (LEDs), fluorescent black lights, arc lamps such as xenon-arc lamps and medium- and low-pressure mercury lamps (including germicidal lamps), microwave-driven lamps, lasers, or combinations thereof. The composition can also be polymerized with higher-intensity light sources available from Fusion UV Systems Inc. Lamps emitting ultraviolet or blue light are typically preferred. UV exposure times for polymerization and curing can vary depending on the intensity of the light source used. For example, full cure with a low-intensity light source can be achieved with exposure times ranging from about 30 to 300 seconds, while full cure with a high-intensity light source can be achieved with shorter exposure times ranging from about 5 to 20 seconds. Partial cure with a high-intensity light source can typically be achieved with exposure times ranging from about 2 seconds to about 5 or 10 seconds. In some embodiments, post-cure can be carried out at temperatures ranging from 170°C to 250°C for 0.1 to 24 hours.

[0206] In some embodiments, post-curing of the fluoropolymer can optionally be carried out at lower temperatures. Lower temperature post-curing is suitable for coating heat-sensitive substrates. In some embodiments, post-curing is carried out at temperatures ranging from 100, 110, 120, 130, 135, or 140°C up to 170°C for 5-10 minutes to 24 hours. In some embodiments, the temperature is no greater than 169, 168, 167, 166, 165, 164, 163, 162, 161, or 160°C. In some embodiments, the temperature is no greater than 135, 130, 125, or 120°C. In preferred embodiments, after curing, the fluoropolymer It is well cross-linked , the at least 80, 85, 90, 95, or 100% by weight but in a fluorinated solvent (e.g., 3-ethoxyperfluoro-2-methylhexane) at 25°C for up to 12 hours. , at a weight ratio of 5 wt.% fluoropolymer to 95 wt.% fluorinated solvent So that it cannot be dissolved become .

[0207] The composition can be used to impregnate a substrate, print (e.g., screen print) onto a substrate, or coat a substrate, for example, but not limited to, spray coating, paint dip coating, roller coating, bar coating, solvent casting, paste coating, etc. The substrate can be organic, inorganic, or a combination thereof. Suitable substrates can include any solid surface, including substrates selected from glass, plastic (e.g., polycarbonate), composite materials, metals (stainless steel, aluminum, carbon steel), alloys, wood, and paper, among others. The coating can be colored if the composition contains a pigment, e.g., titanium dioxide, or a black filler such as graphite or soot, or colorless if no pigment or black filler is present.

[0208] Bonding agents and primers may be used to pretreat the surface of the substrate before coating. For example, adhesion of a coating to a metal surface can be improved by applying an adhesive or primer. Examples include commercially available primers or adhesives, such as those sold under the trade name CHEMLOK.

[0209] Articles containing a coating of the compositions described herein include, but are not limited to, impregnated fabrics, such as protective clothing. Another example of an impregnated fabric is a glass scrim impregnated with the fluoropolymer composition (e.g., silica-containing) described herein. The fabric may include woven or nonwoven fabrics. Other articles include articles exposed to corrosive environments, such as seals and sealing parts and valves used in chemical processing, including, but not limited to, chemical reactors, molds, parts or linings of chemical processing equipment, such as etching, or particularly corrosive materials or hydrocarbon fuels or solvents; combustion engines, electrodes, fuel transport, acid and base containers and systems, valves, pumps and tubing for electrolytic cells, fuel cells, electrolytic cells, and articles used in or for etching.

[0210] An advantage of the coating compositions described herein is that they can be used to prepare thick or thin coatings or fluoropolymer sheets. In some embodiments, the dried and cured fluoropolymer has a thickness of 0.1 micron to 1 or 2 mils. In some embodiments, the dried and cured fluoropolymer has a thickness of at least 0.2, 0.3, 0.4, 0.5, or 0.6 microns. In some embodiments, the dried and cured fluoropolymer has a thickness of at least 1, 2, 3, 4, 5, or 6 microns.

[0211] In typical embodiments, the dried and cured (i.e., crosslinked) composition has a low dielectric constant (Dk), typically less than 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90. In some embodiments, the dielectric constant is at least 2.02, 2.03, 2.04, 2.05. The dried and cured (i.e., crosslinked) composition has a low dielectric constant (Dk). tangent , typically less than 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002, 0.001, 0.0009, 0.0008, 0.0007, 0.0006, 0.0005, 0.0004, 0.0003. tangent is at least 0.00022, 0.00023, 0.00024, 0.00025.

[0212] The dried and cured coatings may exhibit good adhesion to a variety of substrates (e.g., glass, polycarbonate) as evidenced by the coating exhibiting a Boiling Water Test rating of 2, and preferably 3 or 4, as described in International Application No. PCT / US2019 / 036460. In preferred embodiments, the dried and cured coatings are durable as evidenced by the coating exhibiting a Abrasion Test rating of 2, and preferably 3 or 4, as described in the previously cited International Application No. PCT / US2019 / 036460. In some embodiments, the coatings are durable as evidenced by the Abrasion Test after being subjected to the Boiling Water Test.

[0213] The dried and cured coatings may exhibit good adhesion to metals such as copper. For example, in some embodiments, the T-peel to copper foil ranges from at least 0.1, 0.2, 0.3, 0.4, 0.5, or 0.6 N / mm to at least 1 N / mm (i.e., 10 N / cm), 1.5 N / mm, 2 N / mm, or 2.5 N / mm, as determined by the test method described in the Examples.

[0214] In some embodiments, the dried and cured coating has good hydrophobic and oleophobic properties according to the black oil marker resistance test, i.e., marker fluid beading, described in previously cited International Application No. PCT / US2019 / 036460, and is easily removable with a paper towel or cloth.

[0215] In some embodiments, the dried and cured coating has good hydrophobicity and oleophobicity as determined by contact angle measurements (as determined according to the test methods described in the Examples). In some embodiments, the static, advancing, and / or receding contact angles with water can be at least 100, 105, 110, 115, 120, 125, and typically no greater than 130 degrees. In some embodiments, the advancing and / or receding contact angles with hexadecane can be at least 60, 65, 70, or 75 degrees. In some embodiments, the coating exhibits such contact angles after being subjected to a boiling water test, or a boiling water test and an abrasion test (as determined according to the test methods described in previously cited International Application No. PCT / US2019 / 036460).

[0216] In some embodiments, the dried and cured coating exhibits good corrosion resistance (i.e., does not corrode) according to the acid / base corrosion test described in previously cited International Application No. PCT / US2019 / 036460.

[0217] In some embodiments, the dried and cured coating (eg, film) exhibits low water absorption, eg, less than 0.5, 0.4, 0.3, 0.2, or 0.1, as determined by the Water Uptake Test Method described in the Examples.

[0218] In some embodiments, the compositions exhibit a low coefficient of thermal expansion, as determined by the test methods described in the examples, for example, less than 150, 100, 50, 40, 30, 20, or 10. For some thermal barrier applications, the coefficient of thermal expansion is less critical and can range up to 175, 200, or 225.

[0219] As used herein, the term "partially fluorinated alkyl" refers to an alkyl group in which some, but not all, hydrogen atoms attached to the carbon chain have been replaced with fluorine. For example, a F2HC- group or a FH2C- group is a partially fluorinated methyl group. Alkyl groups in which the remaining hydrogen atoms have been partially or completely replaced with other atoms, such as other halogen atoms such as chlorine, iodine, and / or bromine, are also encompassed by the term "partially fluorinated alkyl," as long as at least one hydrogen atom has been replaced with fluorine. For example, residues of the formula F2ClC- or FHClC- are also partially fluorinated alkyl residues.

[0220] A "partially fluorinated ether" is an ether containing at least one partially fluorinated group, or an ether containing one or more fully fluorinated groups and at least one non-fluorinated group or at least one partially fluorinated group. For example, F2HC-O-CH3, F3C-O-CH3, F2HC-O-CFH2, and F2HC-O-CF3 are examples of partially fluorinated ethers. Ether groups in which the remaining hydrogen atoms are partially or completely replaced with other atoms, such as other halogen atoms such as chlorine, iodine, and / or bromine, are also encompassed by the term "partially fluorinated alkyl," as long as at least one hydrogen is replaced with fluorine. For example, ethers of the formula F2ClC-O-CF3 or FHClC-O-CF3 are also partially fluorinated ethers.

[0221] The terms "perfluorinated alkyl" or "perfluoroalkyl" are used herein to refer to an alkyl group in which all of the hydrogen atoms attached to the alkyl chain have been replaced with fluorine atoms. For example, F3C- represents a perfluoromethyl group.

[0222] A "perfluorinated ether" is an ether in which all hydrogen atoms have been replaced with fluorine atoms. An example of a perfluorinated ether is F3C-O-CF3. The present invention includes the following aspects. (Item 1) 1. A telecommunications article comprising a crosslinked fluoropolymer layer, the fluoropolymer comprising at least 80, 85, or 90% by weight of polymerized units of a perfluorinated monomer, and cure sites. (Item 2) Item 10. The telecommunications article of item 1, wherein the crosslinked fluoropolymer layer is a substrate, a patterned (e.g., photoresist) layer, an insulating layer, a passivation layer, a cladding, a protective layer, or a combination thereof. (Item 3) 3. The telecommunications article according to item 1 or 2, wherein the article is an integrated circuit or a printed circuit board. (Item 4) 4. The telecommunications article according to any one of items 1 to 3, wherein the article is an antenna. (Item 5) 5. The telecommunications article according to item 4, wherein the article is an antenna for a computing device (smartphone, tablet, laptop, desktop) or an outdoor structure. (Item 6) 3. The telecommunications article according to item 1 or 2, wherein the article is an optical cable. (Item 7) the crosslinked fluoropolymer layer i) Dielectric constant (Dk) less than 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95; ii) dielectric loss less than 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002, 0.001, 0.0009, 0.0008, 0.0007, 0.0006; 7. The telecommunications article according to any one of items 1 to 6, comprising: (Item 8) 8. The telecommunications article of any one of items 1 to 7, wherein the fluoropolymer further comprises a cure site selected from nitrile, iodine, bromine, and chlorine. (Item 9) 9. The telecommunications article of any one of items 1 to 8, wherein the perfluorinated monomer is selected from tetrafluoroethene (TFE) and one or more unsaturated perfluoroalkyl ethers. (Item 10) The unsaturated perfluoroalkyl ether of the fluoropolymer has the general formula R f -O-(CF 2 ) n -CF=CF 2 [wherein n is 1 or 0, and R f is a perfluoroalkyl group or a perfluoroether group. (Item 11) the crosslinked fluoropolymer i) peroxides and ethylenically unsaturated compounds; ii) one or more compounds containing an electron donating group and an ethylenically unsaturated group, or iii) Aminoorganosilane ester compounds or ester equivalents 11. The telecommunications article according to any one of items 1 to 10, which is crosslinked with a curing agent selected from: (Item 12) 12. The telecommunication article of any one of items 1 to 11, wherein the curing agent comprises at least two ethylenically unsaturated groups, or at least one ethylenically unsaturated group and at least one alkoxysilane group. (Item 13) 13. The telecommunication article according to item 11 or 12, wherein the ethylenically unsaturated group is selected from (meth)acrylic or alkenyl. (Item 14) 14. The telecommunications article of any one of items 1 to 13, wherein the crosslinked fluoropolymer is crosslinked with an amine curing agent. (Item 15) 15. The telecommunications article of any one of items 1 to 14, wherein the fluoropolymer comprises 40 to 60 wt% of polymerized units of TFE, based on the total weight of the fluoropolymer. (Item 16) 16. The telecommunications article of any one of items 1-15, wherein the crosslinked fluoropolymer comprises no more than 5, 4, 3, 2, 1, or 0.1 wt. % of polymerized units derived from non-fluorinated or partially fluorinated monomers, and / or comprises no more than 5, 4, 3, 2, 1, or 0.1 wt. % of ester-containing linkages. (Item 17) 17. The telecommunications article of any one of items 1 to 16, wherein the crosslinked fluoropolymer is insoluble in 3-ethoxyperfluoro2-methylhexane or 3-methoxyperfluoro4-methylpentane. (Item 18) 18. The telecommunications article of any one of items 1 to 17, wherein the crosslinked fluoropolymer layer further comprises crystalline fluoropolymer particles. (Item 19) 1. A method for forming a patterned fluoropolymer layer, comprising: applying a fluoropolymer film to a substrate; selectively crosslinking portions of said fluoropolymer film by exposure to actinic radiation; removing the uncrosslinked portions of said fluoropolymer film. (Item 20) 20. The method of claim 19, further comprising providing a mask having one or more openings between the fluoropolymer film and a source of actinic radiation, and exposing the fluoropolymer film to actinic radiation through at least one opening in the mask. (Item 21) 21. The method of claim 19, wherein removing the uncrosslinked portion of the fluoropolymer film comprises dissolving the uncrosslinked portion in a solvent. (Item 22) 22. The method according to any one of items 19 to 21, wherein the substrate is substantially insoluble in the solvent. (Item 23) 23. The method according to item 21 or 22, wherein the solvent is a fluorinated solvent. (Item 24) applying the fluoropolymer film to the substrate, applying a coating solution to the substrate, the coating solution comprising: a fluorinated solvent; a fluoropolymer; a curing agent that reacts with said cure sites in the presence of actinic radiation, thereby crosslinking said fluoropolymer; and removing the fluorinated solvent. (Item 25) 25. The method of claim 24, wherein the substrate is substantially insoluble in the fluorinated solvent of the coating solution. (Item 26) 26. The method according to any one of items 19 to 25, wherein the fluorinated solvent for removing the uncrosslinked portion of the fluoropolymer film and the fluorinated solvent of the coating solution are the same or different fluorinated solvents. (Item 27) 27. The method according to any one of items 19 to 26, wherein the substrate is a silicon-containing substrate or a metal (e.g., copper) substrate. (Item 28) 28. The method of any one of items 19 to 27, wherein the fluoropolymer comprises at least 80, 85, or 90 wt.% polymerized units of perfluorinated monomers. (Item 29) 29. The method of any one of items 19 to 28, wherein the fluoropolymer further comprises a cure site selected from nitrile, iodine, bromine, and chlorine. (Item 30) 30. The method according to any one of items 19 to 29, wherein the actinic radiation is ultraviolet light or an electron beam. (Item 31) 31. The method according to any one of items 19 to 30, wherein the fluorinated polymer and curing agent are further characterized according to any one of items 7 to 18. (Item 32) 32. The method according to any one of items 19 to 31, wherein the fluorinated solvent is a partially fluorinated ether. (Item 33) The fluorinated solvent has the formula: C p F 2p+1 -OC q H 2q+1

[0039] wherein q is an integer of 1 to 5, and p is an integer of 5 to 11. (Item 34) Said C p F 2p+1 34. The method according to item 33, wherein the unit is branched. (Item 35) 34. The method according to any one of items 19 to 33, wherein the fluorinated solvent has a GWP of less than 1000. (Item 36) 36. The method of any one of items 19 to 35, wherein the method further comprises applying an electrode material to the patterned fluoropolymer layer. (Item 37) 25. The method according to any one of items 19 to 24, wherein the substrate is a component of an integrated circuit, a printed circuit board, or an antenna. (Item 38) 1. A composition for use in forming a patterned fluoropolymer layer, comprising: a fluoropolymer comprising at least 80, 85, or 90 wt. % polymerized units of a perfluorinated monomer and a cure site selected from nitrile, iodine, bromine, and chlorine; and one or more curing agents that react with said cure sites, thereby crosslinking said fluoropolymer. (Item 39) 39. The composition of claim 38, further comprising a fluorinated solvent. (Item 40) 40. The composition according to item 38 or 39, wherein the fluoropolymer and fluorinated solvent are further characterized according to any one of items 7 to 18 and 32 to 35. (Item 41) 1. A method of making a telecommunications article, comprising: providing a film or coating solution comprising a fluoropolymer comprising at least 80, 85, or 90 weight percent polymerized perfluorinated monomers, cure sites, and one or more curing agents that react with said cure sites, thereby crosslinking said fluoropolymer; applying said film or coating solution to a component of a telecommunications article. (Item 42) 42. The method of claim 41, further comprising crosslinking the fluoropolymer by exposure to heat, actinic radiation, or a combination thereof. (Item 43) 43. The method of claim 41 or 42, wherein the coating solution further comprises a fluorinated solvent. (Item 44) 44. The method according to any one of items 41 to 43, wherein the fluoropolymer and fluorinated solvent are further characterized according to any one of items 7 to 18 and 32 to 35. (Item 45) 45. The method according to any one of items 41 to 44, wherein the component is a component of an integrated circuit, a printed circuit board, an antenna, or an optical cable. (Item 46) 19. The telecommunications article of any one of items 1 to 18, wherein the crosslinked fluoropolymer layer further comprises silica, glass fibers, or a combination thereof. (Item 47) 46. ​​The method of any one of items 19-37 or 41-45, wherein the fluoropolymer film or coating solution further comprises silica, glass fiber, or a combination thereof. (Item 48) 41. The composition according to any one of items 38 to 40, wherein the composition further comprises silica, glass fibers, or a combination thereof. (Item 49) 49. The telecommunications article, method, or composition of any one of items 1 to 48, further comprising a thermally conductive filler. (Item 50) 50. The telecommunications article, composition, or method of any one of items 46 to 49, wherein the silica is fumed silica, fused silica, glass bubbles, or a combination thereof. (Item 51) 51. The telecommunication article, composition, or method of any one of items 46-50, wherein the fumed or fused silica has an aggregate particle size of at least 500 nm, 1 micron, 1.5 microns, or 2 microns. (Item 52) 52. The telecommunications article, composition, or method of any one of items 46 to 51, wherein the silica comprises a hydrophobic surface treatment, and the hydrophobic surface treatment optionally comprises a fluorinated alkoxysilane compound. (Item 53) 54. The telecommunication article, composition, or method of any one of items 46-53, wherein the silica is present in an amount of at least 10, 20, 30, 40, 50, 60, or 70 wt. % based on the total weight % solids of the film, composition, or coating solution. (Item 54) 54. The telecommunications article, composition, or method of any one of items 46 to 53, further comprising a thermally conductive filler. (Item 55) a fluoropolymer comprising at least 80, 85, or 90 wt. % polymerized units of a perfluorinated monomer and a cure site selected from nitrile, iodine, bromine, and chlorine; one or more curatives that react with the cure sites, thereby crosslinking the fluoropolymer; silica, glass fiber, or a combination thereof. (Item 56) 56. The composition of claim 55, further comprising a fluorinated solvent. (Item 57) 55. The composition according to item 53 or 54, wherein the fluoropolymer and fluorinated solvent are further characterized according to any one of items 7 to 18 and 32 to 35. (Item 58) 58. The composition according to item 56 or 57, wherein the silica is further characterized by any one of items 50 to 54. (Item 59) a fluoropolymer comprising at least 80, 85, or 90 wt. % polymerized units of a perfluorinated monomer and a cure site selected from nitrile, iodine, bromine, and chlorine; one or more curatives that react with the cure sites, thereby crosslinking the fluoropolymer; a thermally conductive filler. (Item 60) 60. The composition of claim 59, further comprising a fluorinated solvent. (Item 61) 61. The composition according to item 59 or 60, wherein the fluoropolymer and fluorinated solvent are further characterized according to any one of items 7 to 18 and 32 to 35.

[0223] The following examples are provided to further illustrate the present disclosure without intending to limit the disclosure to the specific examples and embodiments described. [Example]

[0224] Unless otherwise stated or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and elsewhere in this specification are by weight. [Table 3-1] [Table 3-2]

[0225] Preparation of fluorinated ether dienes As described in U.S. Patent No. 5,384,374, a fluorinated ether diol (HO-CH2-CF2-O-(CF2CF2)CF2-CH2-OH (0.16 mol)) having an average molecular weight of 1500 and an average hydroxyl functionality of 1.8 was reacted with sodium methoxide (0.34 mol) and then with allyl bromide (40 g, 0.36 mol) in a 250 mL three-neck flask equipped with a condenser at 60° C. overnight. After the reaction, the reaction mixture was washed with water, and the pale yellow liquid was dried over CaCl2 before rotavapor to remove any remaining allyl bromide.

[0226] General Procedure - Preparation of perfluoroelastomeric PFE coating solution with multifunctional alkene / aminosilane ester photocrosslinker: Perfluoroelastomer PFE-1 and PFE-2 solutions were prepared by cutting the gum into small pieces separately and adding them to HFE solvent (HFE-7300 or HFE-7500) to make a 10 wt% PFE in HFE solution (10 g PFE and 90 g HFE). The container was sealed with PTFE tape and paraffin film. The solution was subjected to vigorous shaking overnight (approximately 12 hours) to ensure complete homogenization.

[0227] All aminosilanes and initiators were dissolved or dispersed in HFE to form 1 wt% or 5 wt% solutions or suspensions (e.g., 0.5 g of TAIC was added to 9.5 g of HFE to form a 5 wt% suspension in a vial). To the PFE solution, an amine (e.g., aminosilane), alkene, and optionally a photoinitiator were added. For example, a sample (5% TAIC, 1% APES, 2% TMOS) was prepared by adding 0.3157 g of TAIC suspension (5 wt% in HFE), 0.0606 g of APES suspension (5 wt% in HFE), and 0.1224 g of TMOS solution (5 wt% in 7500) to 3 g of PFE-1 solution (10 wt% in PFE-1). Many silanes form suspensions rather than solutions in HFE. Such suspensions were homogenized using a vortex shaker at 1000 rpm for 10 seconds to form a well-dispersed slurry, which was then added to the PFE-HFE solution, and the percentages in the formula (e.g., 5%, 3%, 1%) were mass fractions based on the solid content of PFE (e.g., PFE-1 + 5% APES + 2% 1173 means: PFE-1 / APES solids = 95:5 and PFE-1 / 1173 solids = 98:2).

[0228] General Procedure - Preparation of Perfluoroelastomer PFE Coating Solution with Fluorinated Alkene / Aminosilane Ester Photocrosslinker: Using a similar method to that described above, perfluoroelastomer PFE-1 and PFE-2 solutions were prepared by cutting the gum into small pieces separately and placing them in HFE solvent to obtain a 10 wt% solution of PFE in HFE in a glass jar. The glass jar was sealed with Teflon tape and paraffin film. The solution was subjected to vigorous shaking overnight (approximately 12 hours) until completely homogenous. Most of the alkene was dissolved or dispersed in HFE to form a 1 wt% or 5 wt% solution or suspension. In cases where there was rapid phase separation between the alkene and HFE solution, and in cases where the alkene sample was solid at room temperature and did not disperse completely in HFE-7500, the alkene was dissolved in methanol or methoxypropanol instead. These alkenes include 4,4'-bis((1,2,2-trifluorovinyl)oxy)-1,1'-biphenyl (dissolved in methanol), chloro-1,2-phenylenediacrylate (dissolved in methanol), perchloro-1,2-phenylenediacrylate (dissolved in methoxypropanol), and 2,4,6-tribromobenzene-1,3,5-triyl triacrylate (dissolved in methoxypropanol). In addition to the alkenes, all silanes and photoinitiators were dissolved or dispersed in HFE to form 1 wt% or 5 wt% solutions or suspensions. To the PFE were added the alkene or polyfunctional alkene and other chemicals, including silanes and initiators, as indicated in the table.

[0229] Split-post dielectric resonator measurements at 25GHz All split post dielectric resonator measurements were performed in accordance with standard IEC 61189-2-721 at frequencies near 25 GHz. Each thin material or film was inserted between two fixed dielectric resonators. The resonant frequency and quality factor of the post were affected by the presence of the test specimen, which in turn affected the complex permittivity (dielectric constant and dielectric constant). tangent The geometry of the split dielectric resonator fixture used in our measurements was designed by QWED (Warsaw, Poland). This 25 GHz resonator has a TE with only an azimuthal electric field component. 01dBecause they operate in a sine wave mode, the electric field remains continuous at the dielectric interface. The split-post dielectric resonators measure the permittivity components in the plane of the specimen. Loop coupling (critically coupled) was used in each of these dielectric resonator measurements. This 25 GHz split-post resonator measurement system was coupled with a Keysight VNA (Vector Network Analyzer Model PNA 8364C 10 MHz to 50 GHz). Calculations were performed using QWED's commercial analytical split-post resonator software, providing a powerful measurement tool for determining the complex permittivity of each specimen at 25 GHz.

[0230] Coefficient of Thermal Expansion (CTE) measurement CTE measurements were performed using a Thermomechanical Analyzer (TMA) TMA Q400 from TA Instrument. Film samples were cut into rectangular shapes (4.5 mm x 24 mm) and mounted in tension clamps. The samples were heated to at least 150°C using a ramp rate of 3.00°C / min and then cooled to room temperature at the same rate. The samples were then heated again to the target temperature. The calculated CTE from the second cycle was reported.

[0231] Water uptake measurement Water absorption measurements were performed using a Q500SA vapor absorption analyzer from TA Instrument. Samples were placed in a quartz pan located within a programmable chamber. Approximately 5 mg of sample was used for each measurement. The samples were first dried in the chamber until the weight did not change for more than 20 minutes. The samples were then placed under conditions of 60°C and 50% humidity until weight equilibrium was achieved. Water absorption values ​​were calculated based on the weight gain of the sample divided by the original weight.

[0232] T-type peeling measurement The films were laminated with Cu foil for 20 minutes at 24°C. The laminated samples were cut into 0.5 inch wide strips for T-peel measurements. Measurements were performed using an Instron electromechanical universal testing machine using the ASTM D1876 standard method.

[0233] static contact angle Static contact angle measurements were performed using deionized water on a drop shape analyzer DSA100 from KRUSS (Germany). The reported values ​​were the average of at least three drops measured on the right and left sides of the drop. For static measurements, the drop volume was 5 μL.

[0234] Table 2. Crosslinking yield of cured fluoropolymers For crosslinking yield studies, samples were prepared by depositing 3 g of solution onto PET film. The coated film was dried at ambient temperature for 2 hours and at 50°C for 20 minutes. After the samples were completely dry, the PET film samples were placed on a wood or stainless steel board and cured under a single 500-watt H-bulb or 500-watt D-bulb UV lamp at a speed of 30 feet per minute in 5-10 runs (as indicated in the table). After UV curing, many samples were also heat-cured in an oven at 120°C for 5 minutes (as indicated in the table). Some of the same samples were also subjected to heat-curing conditions without UV curing.

[0235] The UV-cured samples (1-2 mil thick) were peeled from the PET film, weighed, and then dissolved in HFE in a vial. The mass ratio of cured PFE sample to HFE solvent was 5 / 95. The vial was subjected to vigorous shaking overnight (approximately 12 hours), after which any observations were recorded, as described in the table below. The precipitated sample in the HFE solution (i.e., cross-linked PFE) was collected, dried, and weighed. In some cases, the gel (i.e., less cross-linked PFE) was collected, dried, and weighed. [Table 4] [Table 5] [Table 6] [Table 7] [Table 8] [Table 9] [Table 10] [Table 11] [Table 12]

[0236] Preparation of fluoropolymer solutions with dispersed crystalline fluoropolymer particles: Perfluoroelastomer latex PFE-1 was mixed with crystalline fluoropolymer latex PFA, PTFE, or THV, respectively, in the weight ratios listed in Table 11. The solutions were vortex mixed for 1 to 2 minutes. The thoroughly mixed solutions were then frozen at -20°C for 4 hours, then removed and thawed in warm water. After thawing, the precipitate was filtered and washed with deionized (DI) water. The resulting solids were dried in an oven at 100°C for 1 to 2 hours. The dried coagulated solids were mixed with HFE to form a 10 wt% solution in HFE. TAIC and APS were also added to the HFE compositions as shown in Table 11. Each composition was placed in a shaker for 3 to 4 hours to obtain a stable, well-dispersed, homogeneous composition.

[0237] Samples were prepared by depositing 3 g of the solution onto PET film. The coated film was dried at ambient temperature for 2 hours and at 50°C for 20 minutes. After the samples were completely dry, the PET film samples were placed on a wood or stainless steel board and cured under a single 500-watt H-bulb at a speed of 30 feet per minute in 5 to 10 runs (as indicated in the table). After UV curing, some samples were also heat cured in an oven at 120°C for 5 minutes (as indicated in Table 11).

[0238] The UV-cured samples (1-2 mil thick) were peeled from the PET film, weighed, and then dissolved in HFE in a vial. The mass ratio of cured PFE sample to HFE solvent was 5 / 95. The vial was subjected to vigorous shaking overnight (approximately 12 hours), after which any observations were recorded, as described in the table below. The precipitated sample in the HFE solution (i.e., crosslinked PFE) was collected, dried, and weighed. [Table 13]

[0239] Table 12. Effect of aminosilane esters on UV curing of PFE-1 Perfluoroelastomer PFE-1 solution was prepared by cutting the gums separately into small pieces and adding them to HFE solvent (HFE-7300 or HFE-7500) to make a 10 wt% PFE in HFE solution (10 g PFE and 90 g HFE), as described above. Aminosilane, alkoxysilane, and 1173 were dissolved or dispersed in HFE to form 1 wt% or 5 wt% solutions or suspensions, which were then combined with the PFE-1 solution, as described above. [Table 14] [Table 15]

[0240] Some of the compositions of Examples 12-1 to 13-1 were cured with a D bulb instead of an H bulb and provided similar crosslinking results.

[0241] Basic Procedure - Compounded Fluoropolymer (CFP) with Inorganic Filler: Compounded fluoropolymer (CFP) was prepared using conventional rubber processing equipment by combining 100 g of perfluoroelastomer with filler to provide a well-mixed solid mixture of perfluoroelastomer and filler according to Table 14. Glass bubbles were treated with a fluorinated hydrophobic surface treatment prior to use. [Table 16]

[0242] SRC220 Surface Treatment Glass Bubbles A solution was prepared by adding 9 g of 3M Stain Resistant Additive SRC220 (aqueous fluorinated polyurethane dispersion, 15% solids) to 50 g of DI water, stirring for 5 minutes, and transferring the solution to a 60 mL syringe with an 18-gauge needle syringe.

[0243] 900g of iM16K Glass Bubbles was added to a 1-gallon Lodige Popenmier mixer. The surface treatment solution was sprayed while mixing at 400 rpm. After mixing for 15 minutes at room temperature, the mixing vessel was heated to 120-130°C for 1.5 hours.

[0244] Basic procedure for coating with PFE-3 and CQ0382 or CQ1082: The PFE coating solution was prepared generally as described above to yield a 9 wt% solution in HFE. Fused silica filler was separately dispersed in HFE using a high-speed mixer to form a 50 wt% solids dispersion. The PFE solution and fused silica dispersion were mixed together, followed by the addition of the curing agent, alkoxysilane, and glass fiber. PFE composite films were obtained by coating the solution with a comma bar coater with a gap of 300 μm to 350 μm. The resulting coating was coated onto a release liner (precoated with a fluorinated release coating) and then dried in an oven at 100°C to remove the solvent. The film was then separated from the liner, placed on a Teflon-coated metal tray, and baked at 160°C to 200°C to crosslink the system. The resulting film thickness ranged from 230 μm to 290 μm. The films were characterized using different test methods. The component (i.e., solids) concentrations and results are summarized in Tables 15 to 17. [Table 17] [Table 18] [Table 19]

[0245] Basic procedure for coating from PFE-3 and fused silica (SF550): A solution of PFE-3 containing fused silica in HFE was prepared generally as described above using PFE-3 gum (20 g, cut into small pieces), 3M fused silica (8.6 g, FS550), and HFE (290 g). A stable coating solution had 6.45 wt% PFE-3, with a 70 / 30 weight ratio of PFE-3 to FS550. Similarly, a 6.45% coating solution with an 80 / 20 weight ratio of PFE-3 to fused silica was prepared using 20 g PFE-3, 6.0 g FS550, and 290 g HFE.

[0246] All crosslinkers (e.g., BTESPA) were dissolved in HFE to form 5% or 10% solutions. 3% to 5% of the BTESPA crosslinker was formulated into the PFE-3 / FS550 solution based on the amount of PFE. The alkoxysilane compounds were formulated with the PFE-3 / FS550 solution based on the weight of FS550, as shown below. After thorough mixing, the solutions were coated onto either RL film or DuPont PFA film at different thicknesses and then cured in an oven at 140°C for 5 hours. Coatings on release liners were removed from the liner before testing, and coatings on PFA film were tested directly on the PFA film. CTE was tested from films peeled from the liner. The formulations and test results are summarized in Tables 18 and 19. In some examples, moisture uptake (23°C / 5-95% RH) was measured. The moisture uptake of sample 18.6 was 0.11%. [Table 20] [Table 21]

[0247] Coatings from compounded fluoropolymers: For the coating solution formulation, all CFP (20 g, cut into small pieces) was first dissolved in HFE (180 g) to obtain a 10% solution after vigorously shaking overnight in a sealed glass bottle. All crosslinkers (e.g., BTESPA) were dissolved in HFE to obtain 5% or 10% solutions. All crosslinkers were formulated into the CFP solution based on the total weight of the CFP, as shown in Table 20. After thorough mixing, the solutions were coated onto either RL film, DuPont PFA film, or FEP film at different thicknesses and then cured in an oven at 140°C for 5 hours before testing. Coatings on release liners were removed from the liner before testing, and coatings on PFA film were tested directly on the PFA film. CTE was tested from films peeled from the liner. The results are summarized in Tables 20 and 21. For some of the examples, water uptake (23°C / 5-95% RH) was measured. Two examples that showed good water uptake were 20.12 and 20.14, which had water uptake of 0.15% and 0.13%, respectively. [Table 22] [Table 23]

[0248] UV cured formulated fluoropolymer coatings: A 10% coating solution of compounded fluoropolymer with inorganic filler (e.g., silica) was prepared generally as described above from 20 g of PFE-1-based CFP gum (cut into small pieces) and 180 g of HFE after vigorously shaking overnight at room temperature in a sealed glass bottle. The crosslinkers (BTESPA and TAIC) were dispersed in the HFE to obtain a 5% solution. All crosslinkers (BTESPA and TAIC) were formulated into the CFP solution based on the total weight of the CFP as shown below. After thorough mixing, the solution was coated onto either DuPont PFA film or FEP film at different thicknesses. The coatings were first dried in an oven at 100°C for 5 minutes and then cured with an H-bulb UV at 100% power under nitrogen with 10 passes at 30 fpm. The results are summarized in Table 22. [Table 24]

[0249] Basic procedure for coating from PFE-3 and silica particles: The PFE coating solution was prepared generally as described above to yield a 5 wt% solution of PFE-3 in HFE-7300. Fused silica filler was separately dispersed in the HFE in a high-speed mixer to form a 50 wt% solids dispersion.

[0250] Bis(3-trimethoxysilylpropyl)amine (BTMSPA) was dissolved or dispersed in HFE-7300 to form a 10 wt. % solution or suspension. BTMSPA and silica particles were added to the PFE-3 solution as shown in Table 23. The BTMSPA in the HFE-7300 solution was homogenized using a vortex shaker at 1000 revolutions per minute (rpm) for 10 seconds to form a well-dispersed slurry, which was then added to the PFE-3 / HFE-7300 solution. The percentages shown in the formula (e.g., 5%, 2%) were mass fractions based on the solid content of PFE-3. For example, PFE-3 + 5% BTMSPA means a PFE-3 / APES solids ratio of 95:5. The above prepared solution was typically vortexed at 2500 rpm for 1-2 minutes. All of the above prepared solutions were coated onto a clean PET release liner or copper foil with a No. 24 Meyer rod, and the resulting coatings were typically cured for 20 minutes to 1 hour at 165°C. The cured films were peeled from the liner and evaluated for Dk, Df, water uptake, and CTE. [Table 25]

[0251] Basic Procedure for Preparing Perfluoroelastomer-Perfluoropolastic Nanoparticle Dispersion Coating Solutions: PFE-PFA or PFE-PTFE Coagulation and Dispersion Preparation Perfluoroelastomer PFE-3 (30.5 wt%) was co-coagulated with PFA latex (30 wt% PFA-2 latex) or PTFE latex (30 wt% obtained from dilution of 55 wt% TFM-2 latex) in the ratios listed in Table 24. The latex solutions were mixed and placed on a roller for 20 minutes. The well-mixed solutions were then frozen overnight in a refrigerator. They were then removed and thawed in hot water or in an oven at 60°C. After melting, the precipitate was filtered and washed at least three times with deionized (DI) water. The resulting solids were dried overnight in an air-circulating oven at 55-65°C. The dried PFE / PFA-2 and PFE / PTFE co-coagulated solids were mixed with HFE-7300 separately in 5-20 wt% solutions. They were placed on a shaker or roller at a speed of 80 cycles / min overnight or longer to obtain stable, well-dispersed solutions in HFE-7300 (Table 24).

[0252] The general procedure for the preparation of perfluoropolymer coating solutions, optionally with aminosilane ester or fluorinated amidine curing agents and inorganic fillers including spherical silica, fiberglass particles, and boron nitride particles, for coating, electrical property measurements, and copper bond adhesion measurements: PFE-3, PFE-3 / PFA-2, or PFE-3 / PTFE was dissolved / dispersed in HFE-7300 by cutting the fluoropolymer material into small pieces, placing them in separate glass jars, and adding HFE-7300 solvent to each jar. The containers were then sealed thoroughly with PTFE tape and paraffin film. The solutions were then vigorously shaken overnight (approximately 12 hours) to obtain a completely homogenous solution of 5-8 wt% PFE-3 in HFE-7300 (e.g., 5 g of PFE-3 and 95 g of HFE-7300), 10 wt% PFE-3 / PTFE, or PFE-3 / PFA-2 in HFE-7300.

[0253] To prepare fully fluorinated polymer HFE solutions for coating, BTMSPA, aminosilane, or fluorinated amidine curing agents were added separately to the PFE-3, PFE-3 / PTFE, or PFE-3 / PFA-2 dispersions in the percentages listed in Table 24. For coating solutions containing inorganic fillers, the inorganic or mixed fillers were weighed separately in glass jars, and a small amount of HFE solvent was added to each inorganic or mixed filler and vortexed for 1 to 2 minutes. The amounts of the fluoropolymer HFE solution and curing agent prepared above were added separately to the HFE-7300 filler or mixed filler slurry in the ratios listed in Table 24.

[0254] An alternative method for preparing the inorganic filler-containing fluoropolymer-HFE solution described above involves first mixing the fluoropolymer PFE-3, PFE-3 / PFA-2, or PFE-3 / PTFE with one or more inorganic fillers in the appropriate ratio, followed by adding the amount of HFE-7300 to achieve the specific weight percent solution concentration listed in Table 24. The resulting solution was placed on a shaker or roller at a speed of 80 cycles / min overnight or longer. The resulting solution was homogeneous. Aminosilane BTMSPA or other curing agent was added to the freshly prepared fluoropolymer-inorganic filler-HFE-7300 solution in the ratio listed in Table 24. The percentages in the formula (e.g., 5%, 2%) were mass fractions based on the solids content of PFE-3. For example, PFE-3 + 5% BTMSPA means a PFE-3 / APES solids ratio of 95:5. The prepared solution was typically vortexed at 2500 rpm for 1-2 minutes. All of the above prepared solutions were coated onto a 3M release liner with a No. 24 Meyer rod, or the solution was simply poured onto the liner to obtain thicker coating samples, and the resulting coatings were typically dried overnight at room temperature or cured at 120-165°C for 20-105 minutes. The cured films were peeled from the liner and were available for adhesion to copper, Dk / Df measurements, and CTE measurements as shown in Table 24.

[0255] The perfluoropolymer solution was coated onto a release liner and either dried overnight at room temperature or cured for 30 to 105 minutes at 120 to 165°C. The resulting film, with an average thickness of 15 to 40 microns, was peeled from the liner and then laminated to Cu foil in a sandwich structure for bonding, typically for 30 minutes, at the temperature indicated in the table and under 1 to 2 tons of pressure. [Table 26]

[0256] Basic procedure for the preparation of perfluoropolymer coating solutions with inorganic fillers: A solution containing a co-coagulated perfluoropolymer and one or more inorganic fillers (e.g., silica nanoparticles, quartz fiber, and boron nitride), referred to as a fluoropolymer resin, was dissolved / dispersed in HFE-7300. The solution was prepared in the following stepwise procedure: the dry inorganic and fluoropolymer resins were combined in a container, and HFE-7300 was added. The container was then sealed and gently agitated on a roller overnight or longer until the solution was determined to be fully mixed and ready for coating. The solution was then transferred to a shear mixing container and mixed at 2500-3500 rpm for 3-4 minutes. BTMSPA was added to the thoroughly mixed solution (5% resin by weight in the solution). After adding the BTMSPA, the solution was vortexed to thoroughly mix and then placed on a shaker for 30-60 minutes. The solution was then coated onto a release liner using a No. 24 Meyer rod and tape guide to control film thickness. The film was air-dried at room temperature, then removed from the release liner and heat-cured at 165°C for 1 hour. The cured samples were then ready for testing. [Table 27] [Table 28]

Claims

1. 1. A telecommunications article comprising a crosslinked fluoropolymer layer, the fluoropolymer in the crosslinked fluoropolymer layer comprises at least 80 wt. % polymerized units of a perfluorinated monomer, based on the total weight of the fluoropolymer, and cure sites; The crosslinked fluoropolymer layer comprises: i) a dielectric constant (Dk) of less than 2.75 at a frequency of 25 GHz; and ii) a dissipation factor of less than 0.01 at a frequency of 25 GHz; 1. A telecommunications article that is an integrated circuit, a printed circuit board, an antenna, or an optical cable having a combination of:

2. 10. The telecommunications article of claim 1, wherein the fluoropolymer comprises at least 85% by weight of polymerized units of perfluorinated monomers, based on the total weight of the fluoropolymer.

3. 10. The telecommunications article of claim 1, wherein the fluoropolymer comprises at least 90% by weight of polymerized units of perfluorinated monomers, based on the total weight of the fluoropolymer.

4. 10. The telecommunications article of claim 1, wherein the crosslinked fluoropolymer layer has a dielectric constant (Dk) of less than 2.

50.

5. 10. The telecommunications article of claim 1, wherein the crosslinked fluoropolymer layer has a dielectric constant (Dk) of less than 2.

00.

6. 10. The telecommunications article of claim 1, wherein the crosslinked fluoropolymer layer has a dissipation factor of less than 0.

005.

7. 10. The telecommunications article of claim 1, wherein the crosslinked fluoropolymer layer has a dissipation factor of less than 0.

002.

8. The telecommunications article of any one of claims 1 to 7, wherein the crosslinked fluoropolymer layer is a substrate, a patterned layer, an insulating layer, a passivation layer, a cladding, a protective layer, or a combination thereof.

9. The telecommunication article according to any one of claims 1 to 7, wherein the antenna is an antenna of a computing device (smartphone, tablet, laptop, desktop) or an outdoor structure.

10. The telecommunications article of any one of claims 1 to 7, wherein the fluoropolymer further comprises a cure site selected from nitrile, iodine, bromine, and chlorine.

11. The telecommunications article of any one of claims 1 to 7, wherein the perfluorinated monomer is selected from tetrafluoroethene (TFE) and one or more unsaturated perfluoroalkyl ethers.

12. The unsaturated perfluoroalkyl ether of the fluoropolymer has the general formula R ｆ -O-(CF ２ ) ｎ -CF=CF ２ [wherein n is 1 or 0, and R ｆ is a perfluoroalkyl group or a perfluoroether group.

13. the crosslinked fluoropolymer layer i) peroxides and ethylenically unsaturated compounds; ii) one or more compounds containing an electron-donating group and an ethylenically unsaturated group, or iii) aminoorganosilane ester compounds or ester equivalents The telecommunications article of any one of claims 1 to 7, which is crosslinked with a curing agent selected from:

14. 14. The telecommunications article of claim 13, wherein the curing agent comprises at least two ethylenically unsaturated groups, or at least one ethylenically unsaturated group and at least one alkoxysilane group.

15. The telecommunications article of any one of claims 1 to 7, wherein the crosslinked fluoropolymer layer is crosslinked with an amine curing agent.

16. The telecommunications article of any one of claims 1 to 7, wherein the fluoropolymer comprises 40 to 60 wt% of polymerized units of TFE, based on the total weight of the fluoropolymer.

17. 8. The telecommunications article of any one of claims 1 to 7, wherein the crosslinked fluoropolymer layer comprises no more than 5 wt.% of polymerized units derived from non-fluorinated or partially fluorinated monomers and / or comprises no more than 5 wt.% of ester-containing linkages.

18. The telecommunications article of any one of claims 1 to 7, wherein the crosslinked fluoropolymer layer is insoluble in 3-ethoxyperfluoro2-methylhexane or 3-methoxyperfluoro4-methylpentane.

19. The telecommunications article of any one of claims 1 to 7, wherein the crosslinked fluoropolymer layer further comprises crystalline fluoropolymer particles.

20. The telecommunications article of any one of claims 1 to 19, wherein the crosslinked fluoropolymer layer further comprises silica, glass fibers, or a combination thereof.

21. The telecommunications article of any one of claims 1 to 20, wherein the crosslinked fluoropolymer layer further comprises a thermally conductive filler.

22. 21. The telecommunications article of claim 20, wherein the silica is fumed silica, fused silica, glass bubbles, or a combination thereof.

23. 23. The telecommunications article of claim 22, wherein the fumed or fused silica has an aggregate size of at least 500 nm.

24. 21. The telecommunications article of claim 20, wherein the silica comprises a hydrophobic surface treatment, the hydrophobic surface treatment optionally comprising a fluorinated alkoxysilane compound.

25. 21. The telecommunications article of claim 20, wherein the silica is present in an amount of at least 10% by weight, based on the total amount of the crosslinked fluoropolymer layer.

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