Low dielectric constant low dielectric loss tangent laminate containing an aerogel layer

Abstract

This invention provides a copper-clad laminate with an ultra-low dielectric constant suitable for use in printed circuit boards (PCBs). [Solution] The laminates 10b and 10c include one or more conductive layers 14 and one or more electrically insulating layers 18 bonded to the conductive layers. Each conductive layer may contain at least 90% by weight of copper. Each electrically insulating layer may include a layer of polymer aerogel. For at least one of the opposing front and rear surfaces of the laminate, at least a portion of the surface is defined by one of the conductive layers.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 025,947, filed on 15 May 2020, which is incorporated herein by reference in its entirety without waiver of rights.

[0002] A. Field of Invention The present invention generally relates to copper-clad laminates for use in high-frequency (e.g., 10-300 GHz) electrical applications such as communication systems, antenna systems, electric amplifiers, and radar systems. [Background technology]

[0003] B. Description of related technologies Copper-clad laminates are often used in printed circuit boards (PCBs). Traditionally, a copper-clad laminate comprises one or more thin (e.g., less than 1 inch (mil) of copper, at least one of which defines the outer surface of the laminate, and one or more insulating substrates that can provide structural support to the copper layers. To fabricate a PCB, each of the copper layers can be etched to define separate conductive lines or "traces" that allow electricity to flow between different components bonded to the PCB.

[0004] The substrate properties of a copper-clad laminate can affect the durability and electrical performance of the PCB. For example, the laminate may heat up when components are soldered to the PCB or during the use of the PCB. Thermal expansion of the substrate, especially when its temperature rises above the glass transition temperature (Tg), can cause delamination of the copper layer and / or damage to the joints connecting the components to the PCB. In addition, the rate at which a signal can propagate through the PCB and the amount of electromagnetic energy of the signal wasted on the PCB affect the dielectric constant (D) of the laminate. k ) and dielectric loss tangent (D f It is affected by )

[0005] Substrates used in PCBs include glass fiber woven or nonwoven fabrics dispersed in epoxy resin, polytetrafluoroethylene (PTFE), and paper impregnated with phenol-formaldehyde resin (e.g., phenolic paper). Copper-clad laminates incorporating one or more such substrates often have relatively low dielectric loss tangents (e.g., 0.0009–0.0018 at 10 GHz) which can reduce dielectric loss, but their dielectric constants exceed 2.0. For example, copper-clad laminates of PTFE substrates typically have a dielectric constant of 2.2–2.3 at 10 GHz. When the dielectric constant exceeds 2.0, PCBs using conventional copper-clad laminates may not be able to propagate signals at speeds sufficient to maintain signal integrity in high-frequency applications such as 5G communication systems and high-speed digital circuits. Therefore, there is a need in the art for copper-clad laminates with ultra-low dielectric constants suitable for use in PCBs. [Overview of the project]

[0006] To address this need in the art, some of the laminates of the present invention include one or more conductive layers, each containing at least 90% by weight of copper, and one or more electrically insulating layers bonded to the conductive layers. In some aspects, at least one of the electrically insulating layers may contain a porous material. In some aspects, each of the electrically insulating layers may independently contain a porous material. In certain aspects, the porous material may be an open-cell porous material. In certain other aspects, the porous material may be a closed-cell porous material. In certain aspects, the porous material may be a foam. In certain aspects, the foam may be an organic or silicone foam. Non-limiting examples of organic foams may include polyurethane, polystyrene, polyvinyl chloride, (meth)acrylic polymers, polyamides, polyimides, polyaramids, polyureas, polyesters, polyolefins (e.g., polyethylene, polypropylene, ethylene propylene diene monomer (EPDM) foams, etc.), polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, polyvinyl acetate, ethyl vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), polymethyl methacrylate, polyacrylate, polycarbonate, polysulfonate, or synthetic rubber foams, or any combination thereof. In certain aspects, the foam may be a polyurethane foam. In certain aspects, the porous material may be an aerogel. In some laminates, the electrical insulating layer may each include a polymer aerogel layer. Such aerogel layers may give the laminate an ultra-low dielectric constant (e.g., less than 2.0 at 10 GHz, e.g., 1.7 or less) and an ultra-low dielectric loss tangent (e.g., less than 0.002 at 10 GHz), making it suitable for high-frequency electrical applications.

[0007] The composition of the aerogel layer can enhance the heat resistance of the laminate, making it suitable for use in PCBs. For example, in some embodiments, for at least one of the electrical insulating layers, the polymer aerogel layer has a thermal decomposition temperature of at least 400°C, 450°C, or 500°C. In some embodiments, for at least one of the electrical insulating layers, the polymer aerogel layer contains at least 90% by weight of an organic polymer, and / or at least 90% by weight of polyimide, polyamide, polyaramid, polyurethane, polyurea, and / or polyester. In some embodiments, for at least one of the electrical insulating layers, the polymer aerogel layer includes an open-cell structure and / or includes micropores, mesopores, and / or macropores. In some embodiments, the aerogel layer has a pore volume, where micropores, mesopores, and / or macropores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. In some embodiments, for at least one of the electrical insulating layers, the polymer aerogel layer has an average pore diameter of 2.0 nm to 50 nm or 50 nm to 5,000 nm, optionally 100 nm to 800 nm, 100 nm to 500 nm, 150 nm to 400 nm, 200 nm to 300 nm, or 225 nm to 275 nm. Thus, such a laminate would be able to withstand the heat during PCB manufacturing (e.g., from soldering) and during PCB use.

[0008] In addition, in some embodiments, at least one of the aerogel layers has a thickness of 20 mils or less, 12 mils or less, or 7 mils or less, for example, 3 mils to 20 mils, 3 mils to 15 mils, 3 mils to 12 mils, or 3 mils to 7 mils. Such relatively thin aerogel layers can promote low dielectric constant and low dielectric loss tangent of the laminate. To illustrate, in some embodiments, at least one aerogel layer has i) a dielectric constant less than or equal to any one of 3, 2.75, 2.5, 2.25, 2, 1.75, 1.6, 1.4, 1.3, 1.2, and 1.1 at 10 GHz, or between any two of these values; and / or a dielectric loss tangent less than or equal to any one of 0.005, 0.004, 0.003, 0.0025, 0.00225, 0.002, 0.00175, 0.0015, 0.00125, 0.001, 0.00075, and 0.0005 at 10 GHz, or between any two of these values. For illustrative purposes, in some embodiments, the dielectric constant of the laminate is 2.0 or less, 1.9 or less, 1.8 or less, 1.75 or less, 1.7 or less, or 1.6 or less at 10 GHz, and / or the dielectric loss tangent of the laminate is 0.0025 or less, 0.00225 or less, 0.002 or less, 0.00175 or less, or 0.0015 or less at 10 GHz.

[0009] In some aspects, at least one or more electrical insulating layers may include fibers without the porous material of the present invention. In other aspects, at least one or more electrical insulating layers may include a combination of the porous material of the present invention and fibers (e.g., fibers dispersed or aligned within the porous material). The fibers may be natural, synthetic, semi-synthetic fibers, or a combination thereof. The fibers may include plant, woody, animal, mineral, biological fibers, or a combination thereof. In some specific examples, the fibers may include rayon, bamboo, diacetate, triacetate fibers, polyester fibers, aramid fibers, or a combination thereof. In some embodiments, the fibers may include metallic fibers, carbon fibers, carbide fibers, glass fibers, mineral fibers, basalt fibers, or a combination thereof. In some embodiments, the fibers may include thermoplastic polymer fibers, thermosetting polymer fibers, or a combination thereof. Non-limiting examples of thermoplastic fibers include polyethylene terephthalate (PET), polymers of the polycarbonate (PC) family, polybutylene terephthalate (PBT), poly(1,4-cyclohexylidenecyclohexane-1,4-dicarboxylate) (PCCD), glycol-modified polycyclohexyl terephthalate (PCTG), poly(phenylene oxide) (PPO), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polymethyl methacrylate (PMMA), polyethyleneimine, or polyethere. This includes fibers made from luimide (PEI) and its derivatives, thermoplastic elastomers (TPE), terephthalic acid (TPA) elastomers, poly(cyclohexanedimethylene terephthalate) (PCT), polyethylene naphthalate (PEN), polyamide (PA), polysulfone sulfonate (PSS), polysulfone sulfonate, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), acrylonitrile butyldiene styrene (ABS), polyphenylene sulfide (PPS), copolymers thereof, or mixtures thereof.Non-limiting examples of thermosetting fibers include fibers of unsaturated polyester resins, polyurethanes, polyoxybenzylmethylene glycol anhydride (e.g., Bakelite), urea formaldehyde, diallyl phthalate, epoxy resins, epoxy vinyl esters, polyimides, cyanate esters of polycyanurates, dicyclopentadienes, phenols, benzoxazines, copolymers thereof, or mixtures thereof. In some embodiments, the fibers are polyaramids, polyimides, polybenzoxazoles, polyurethanes, or mixtures thereof. In some embodiments, the fibers are vinylon. In some embodiments, the fibers are polyester fibers. In some embodiments, the fibers are nonwoven fabrics. In some embodiments, the fibers form a fiber matrix. In some embodiments, the fibers are 5 μm thick. 2 ~40,000 μm 2 The average filament cross-sectional area and average length are 20 mm to 100 mm. In some embodiments, the cross-sectional area is 5, 10, 15, 20, 25, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500 μm. 2or between any two of those values. In some embodiments, the fibers have an average length of about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, 2000, 3000, 4000, 5000 mm, or between any two of those values. Bundles of various types of fibers can be used depending on the intended use of the internal reinforcing aerogel. For example, the bundle may be of carbon fibers or ceramic fibers, or of fibers that are carbon or ceramic precursors, glass fibers, aramid fibers, or a mixture of different types of fibers. The bundle can contain any number of fibers. For example, the bundle can contain 400, 750, 800, 1375, 1000, 1500, 3000, 6000, 12000, 24000, 50000, or 60000 filaments. The fibers can have a filament diameter of 5 - 24 microns, 10 - 20 microns, or 12 - 15 microns, or any range between them, or 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 microns, or any value between them. The fibers in the fiber bundle are 7μm 2 ~800μm 2 and can have an average filament cross-sectional area, which is equivalent to an average diameter of 3 - 30 microns for circular fibers. In some embodiments, the fiber matrix includes felt, batting, non-woven fabric, or mat.

[0010] The conductive layer can have a thickness suitable for propagating an electrical signal. In some embodiments, at least one of the conductive layers has a thickness of 0.5 mils - 3 mils, 0.5 mils - 2 mils, or 0.5 mils - 0.9 mils, 1 mil - 2 mils, 1.4 mils, or about 0.7 mils. At least one of the conductive layers, in some embodiments, is 0.35 - 3 ounces per square foot (oz / ft 2 ) or 0.35 - 0.75 oz / ft 2 , for example, about 0.5 oz / ft 2It has a surface density.

[0011] In some embodiments, the laminate includes one or more adhesive layers, respectively, disposed between adjacent layers of conductive and electrically insulating layers. The adhesive layers can bond the other layers together and have properties that enhance the electrical performance of the laminate and reduce delamination. For illustrative purposes, in some embodiments, at least one of the adhesive layers includes a fluoropolymer film, at least one of the adhesive layers includes a polyimide film, and / or at least one of the adhesive layers includes a B-stage epoxy. In some embodiments, at least one of the adhesive layers has a dielectric constant of 3.5 or less, 3.0 or less, 2.5 or less, or 2.25 or less at 10 GHz, and / or a dielectric loss tangent of 0.0040 or less, 0.0035 or less, 0.0030 or less, 0.0025 or less, 0.0020 or less, or 0.0015 or less at 10 GHz. In some embodiments, at least one of the adhesive layers has a decomposition temperature of 350°C or higher, 375°C or higher, 400°C or higher, 450°C or higher, or 500°C or higher, and / or a glass transition temperature or melting point of 100°C or higher, 150°C or higher, 200°C or higher, 225°C or higher, 250°C or higher, or 275°C or higher. In some embodiments, at least one of the adhesive layers has a thickness of 0.3 mil to 5 mil, 0.3 mil to 3.0 mil, 0.3 mil to 2.0 mil, 0.3 mil to 1.2 mil, or 0.75 to 1.25 mil.

[0012] An aerogel, and thus the laminate, can be relatively flexible. For example, in some embodiments, the laminate is arranged in a roll shape such that a part of the front surface of the laminate faces a part of the rear surface of the laminate. In some such embodiments where the laminate is flexible enough to be arranged in a roll shape, the laminate can be used for a flexible circuit board. However, in other embodiments, the laminate can have a sufficiently high rigidity such that it cannot be rolled. For example, in some embodiments, the laminate includes one or more reinforcing layers. Each of the reinforcing layers has a bending rigidity that is at least 10% greater than the bending rigidity of each of the conductive layer and the electrical insulating layer in some embodiments. For at least one of the electrical insulating layers, in some embodiments, at least one of the reinforcing layers is at least partially embedded in the layer of the polymer aerogel such that the Young's modulus of the electrical insulating layer is at least 200 Mpa. At least one of the reinforcing layers includes, in some embodiments, one or more unidirectional sheets, non-woven sheets, or woven sheets each containing fibers. For at least one of the electrical insulating layers, in some embodiments, the plurality of fibers are dispersed in the layer of the polymer aerogel such that the Young's modulus of the electrical insulating layer is at least 200 MPa. At least one of the reinforcing layers includes, in some embodiments, one or more paper sheets. However, in other embodiments, the laminate does not contain fibers.

[0013] For at least one of the opposing front and rear surfaces of the laminate, in some embodiments, at least a portion, optionally at least a majority, of the surface is defined by one of the conductive layers. In some embodiments, one or more conductive layers include two or more conductive layers, where optionally at least a portion of the front surface of the laminate is defined by a first one of the conductive layers and at least a portion of the rear surface of the laminate is defined by a second one of the conductive layers. The electrical insulation layer includes, in some embodiments, two or more, optionally four or more, electrical insulation layers. In some embodiments, no conductive layer is disposed between adjacent layers of the electrical insulation layers. The laminate has, in some embodiments, a thickness of 5 mils to 100 mils, 5 mils to 75 mils, 5 mils to 50 mils, or 5 mils to 30 mils.

[0014] Some of the circuit boards of the present invention include some of the laminates of the present invention and include a solder mask layer bonded to the surface such that the solder mask layer covers at least a majority of the surface for at least one of the front and rear surfaces. The solder mask layer includes, in some embodiments, at least 90 wt% polymer and / or has a thickness of 3.2 mils or less, 1.6 mils or less, or 0.8 mils or less. Some of the devices of the present invention include some of the circuit boards of the present invention and optionally an antenna electrically coupled to the circuit board. In some embodiments, the device is an electrical amplifier, a radar system, or a communication system.

[0015] Similarly, a method for producing a polymer aerogel layer suitable for use in at least some of the laminates of the present invention is also disclosed. The method may include the steps of (a) providing monomers or combinations of monomers to a solvent to form a solution; (b) polymerizing the monomers in the solution to form a polymer gel matrix; and (c) subjecting the polymer gel matrix to conditions sufficient to remove liquid from the polymer gel matrix to form an aerogel having a polymer matrix containing open cell structures. Step (b) may further include the step of adding a curing agent to the solution to reduce the solubility of the polymer formed in the solution and to form macropores in the gel matrix, the formed macropores containing liquid from the solution. The process may include the step of pouring the polymer gel matrix in step (b) onto a support such that a layer of polymer gel matrix is ​​constructed on the support, where the aerogel in step (c) is in the form of a film.

[0016] The porous structure of aerogels, including the amount and volume of macroporous, mesoporous, and microporous cells, can be controlled primarily by controlling the polymer / solvent dynamics during the formation of the polymer gel matrix. As an example, a curing agent can be added to the solution in step (b) to reduce the solubility of the polymer formed in the solution and to form macropores in the gel matrix, the formed macropores containing liquid from the solution. Such a curing agent could be, for example, 1,4-diazabicyclo[2.2.2]octane. Alternatively, to improve the solubility of the polymer formed in the solution, adding a curing agent such as triethylamine to the solution in step (b) will result in the formation of a relatively small number of macropores in the gel matrix. In another example, when forming a polyimide aerogel, increasing the ratio of rigid amines (e.g., p-phenylenediamine (p-PDA)) to more flexible diamines (e.g., 4,4'-oxydianiline (4,4'-ODA)) in the polymer backbone may favor the formation of macropores compared to smaller mesopores and micropores.

[0017] More detailed information regarding monomers, solvents, and processing conditions is broadly described below, but the following can be adjusted to control the porous structure of the aerogel: (1) polymerization solvent; (2) polymerization temperature; (3) polymer molecular weight; (4) molecular weight distribution; (5) copolymer composition; (6) branching amount; (7) crosslinking amount; (8) branching method; (9) crosslinking method; (10) method used for gel formation; (11) type of catalyst used for gel formation; (12) chemical composition of the catalyst used for gel formation; (13) amount of catalyst used for gel formation; (14) gel formation temperature; (15) type of gas flowing over the material during gel formation; (16) velocity of gas flowing over the material during gel formation; (17) atmospheric pressure during gel formation; (18) removal of dissolved gases during gel formation; (19) presence of solid additives in the resin during gel formation; (20) duration of the gel formation process; (21) substrate used for gel formation; (22) at each stage of any solvent exchange process. (23) the type of solvent used; (24) the composition of the solvent used in each stage of any solvent exchange process; (25) the time used in each stage of any solvent exchange process; (26) the residence time of the portion in each stage of the solvent exchange process; (27) the flow rate of any solvent exchange solvent; (28) the stirring speed of any solvent exchange solvent; (29) the temperature used in each stage of any solvent exchange process; (30) the ratio of the volume of any solvent exchange solvent to the volume of the portion; (31) the drying method; (32) the temperature at each stage of the drying process; (33) the pressure at each stage of the drying process; (34) the composition of the gas used in each stage of the drying process; (35) the gas flow rate in each stage of the drying process; (36) the gas temperature in each stage of the drying process; (37) the temperature of the portion in each stage of the drying process; (38) the presence of an enclosure around the portion in each stage of the drying process; (39) the type of enclosure around the portion during drying; and / or (40) the solvent used in each stage of the drying process.

[0018] The term "aerogel" generally refers to a class of materials produced by forming a gel, removing a mobile intervening solvent phase from the pores, and then replacing it with a gas or gaseous material. By controlling the gel and evaporation system, density, shrinkage, and pore collapse can be minimized. The aerogels of the present invention may include macropores, mesopores, and / or micropores. In a preferred scenario, macropores may occupy the majority of the pore volume of the aerogel (e.g., more than 50%). In other alternative scenarios, mesopores and / or micropores may occupy the majority of the pore volume of the aerogel, such that macropores occupy less than 50% of the pore volume of the aerogel. In some embodiments, the aerogels of the present invention have a low bulk density (about 0.75 g / cm³). 3 Preferably about 0.01 g / cm³ 3 ~0.5g / cm 3 ), high surface area (generally about 10m²) 2 / g~1,000m 2 / g or more, preferably about 50m 2 / g~1000m 2 It may have high porosity (about 20% or more, preferably more than about 85%) and / or a relatively large pore volume (more than about 0.3 mL / g, preferably more than about 1.2 mL / g).

[0019] The presence of macropores, mesopores, and / or micropores in the aerogel of the present invention can be determined by mercury intrusion porosimetry (MIP) and / or gas physicoadsorption experiments. MIP testing can be used to measure mesopores and macropores (i.e., American Standard Testing Method (ASTM) D4404-10, Standard Test Method for Determination of Pore Volume and Pore Volume Distribution of Soil and Rock by Mercury Intrusion Porosimetry). Gas physicoadsorption experiments can be used to measure micropores (i.e., ASTM D1993-03 (2008) Standard Test Method for Precipitated Silica - Surface Area by Multipoint BET Nitrogen).

[0020] The "decomposition temperature" of a material is the temperature at which 2%, 5%, or 10% of a sample of the material decomposes when heated in an environment that reaches that temperature. The decomposition temperature can be measured by placing the sample in a thermogravimetric analyzer (TGA), heating the sample from the ambient temperature inside the TGA (for example, at a rate of 10°C / min), and recording the temperature at which the sample's mass is 2%, 5%, or 10% lower than its initial mass as the decomposition temperature.

[0021] The term "combined" is defined as being linked, but not necessarily directly or mechanically. Two "combined" items may be single entities or linked to each other through one or more intermediate components or elements.

[0022] The terms “a” and “an” are defined as one or more unless the disclosure expressly requires otherwise.

[0023] The term “substantially” is defined as being largely but not entirely the specified (and including the specified; for example, substantially 90 degrees includes 90 degrees, and substantially parallel includes parallel). In any disclosed embodiment, the terms “substantially,” “approximately,” and “about” may be replaced with “within [a certain percentage]” of the specified, where the percentage is 0.1, 1, 5, or 10%.

[0024] The phrase "and / or" means "and or." For example, A, B, and / or C include: A only, B only, C only, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C. In other words, "and / or" functions as an inclusive or.

[0025] The terms “comprise” (and any form of “comprises” and “comprising”), “have” (and any form of “has” and “having”), “include” (and any form of “includes” and “including”), and “contain” (and any form of “contains” and “containing”) are open-ended linking verbs. As a result, a device that “comprises,” “has,” “includes,” or “contains” one or more elements has, but is not limited to having only, those one or more elements. Similarly, a method that “comprises,” “has,” “includes,” or “contains” one or more stages has, but is not limited to having, those one or more stages.

[0026] Any aspect of any apparatus and method may consist of or essentially consist of any described elements, features, and / or steps, rather than comprise / have / include / contain them. Accordingly, in any of the claims, the phrase "consists of" or "essentially consists of" can be used in place of any of the aforementioned open-ended linking verbs to modify a given claim from one which otherwise used an open-ended linking verb.

[0027] Unless expressly prohibited by the nature of this disclosure or the aspects thereof, features of one aspect may be applied to other aspects, even if not described or illustrated.

[0028] [Invention 1001] One or more conductive layers, each containing at least 90% by weight of copper, One or more electrically insulating layers bonded to a conductive layer, each comprising a polymer aerogel layer, and A laminate including, At least one of the opposing front and rear surfaces of the laminate is defined by one of the conductive layers. Laminated structure. [Invention 1002] The conductive layer comprises two or more conductive layers. At least a portion of the front surface of the laminate is defined by one of the first conductive layers, and At least a portion of the rear surface of the laminate is defined by one of the second conductive layers. A laminate according to the present invention 1001. [Invention 1003] A laminate according to the present invention 1001 or 1002, wherein at least one conductive layer has a thickness of 0.5 mil to 3.0 mil or 0.5 mil to 0.9 mil. [Invention 1004] A laminate according to the present invention 1003, wherein at least one of the conductive layers has a thickness of about 0.7 mils. [Invention 1005] At least one of the conductive layers has a conductivity of 0.35 to 3.0 ounces per square foot (oz / ft 2 ) or 0.35~0.75 oz / ft 2 A laminate according to any of the present invention 1001 to 1004 having a surface density. [Invention 1006] At least one of the conductive layers is approximately 0.5 oz / ft 2 A laminate of the present invention 1005 having a surface density. [Invention 1007] A laminate according to any one of the invention 1001 to 1006, wherein at least one of the electrical insulating layers includes a polymer aerogel layer with an open-cell structure. [Invention 1008] A laminate according to any one of the present invention 1001 to 1007, wherein at least one of the electrical insulating layers comprises a polymer aerogel layer with micropores, mesopores, and / or macropores. [Invention 1009] For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Micropores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. A laminate according to the present invention 1008. [Invention 1010] For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Mesopores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. A laminate according to the present invention 1008. [Invention 1011] For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Macropores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. A laminate according to the present invention 1008. [Invention 1012] For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Micropores and / or mesopores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. A laminate according to the present invention 1008. [Invention 1013] A laminate according to any one of the present invention 1001 to 1007, wherein at least one of the electrical insulating layers is a polymer aerogel layer having an average pore diameter of 2.0 nm to 50 nm. [Invention 1014] A laminate according to any one of the present invention 1001 to 1007, wherein at least one of the electrical insulating layers is a polymer aerogel layer having an average pore diameter of 50 nm to 5,000 nm. [Invention 1015] A laminate according to the present invention 1014, wherein the average pore diameter is 100nm to 800nm, 100nm to 500nm, 150nm to 400nm, 200nm to 300nm, or 225nm to 275nm. [Invention 1016] A laminate according to any one of invention 1001 to 1015, wherein at least one of the electrical insulating layers is a polymer aerogel layer containing at least 90% by weight of an organic polymer. [Invention 1017] A laminate according to any one of invention 1001 to 1015, wherein at least one of the electrical insulating layers is a polymer aerogel layer containing at least 90% by weight of polyimide, polyamide, polyaramid, polyurethane, polyurea, and / or polyester. [Invention 1018] A laminate of the present invention 1017, wherein at least one of the electrical insulating layers is a polymer aerogel layer containing at least 90% by weight of polyimide. [Invention 1019] A laminate according to any one of the present invention 1001 to 1018, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 20 mils or less. [Invention 1020] A laminate according to the present invention 1019, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 12 mils or less. [Invention 1021] A laminate according to the present invention 1020, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 7.0 mil or less. [Invention 1022] A laminate according to any one of the invention 1001 to 1018, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 3.0 to 20 mils, 3.0 to 15 mils, 3.0 to 12 mils, or 3.0 to 7.0 mils. [Invention 1023] A laminate according to any one of the invention 1001 to 1022, wherein at least one of the electrical insulating layers is a polymer aerogel layer having a decomposition temperature of 400°C or higher, 450°C or higher, or 500°C or higher. [Invention 1024] One or more adhesive layers are placed between adjacent layers of the conductive layer and the electrically insulating layer, respectively. A laminate according to any of the present invention 1001 to 1023, including the above. [Invention 1025] A laminate according to the present invention 1024, wherein at least one of the adhesive layers includes a fluoropolymer film. [Invention 1026] A laminate according to the present invention 1024, wherein at least one of the adhesive layers includes a polyimide film. [Invention 1027] A laminate according to the present invention 1024, wherein at least one of the adhesive layers contains B-stage epoxy. [Invention 1028] A laminate according to any one of the present invention 1024 to 1027, wherein at least one of the adhesive layers has a dielectric constant of 3.5 or less, 3.0 or less, 2.5 or less, or 2.25 or less at 10 GHz. [Invention 1029] A laminate according to any of inventions 1024 to 1028, wherein at least one of the adhesive layers has a dielectric loss tangent of 0.0040 or less, 0.0035 or less, 0.0030 or less, 0.0025 or less, 0.0020 or less, or 0.0015 or less at 10 GHz. [Invention 1030] A laminate according to any of the present invention 1024 to 1029, wherein at least one of the adhesive layers has a decomposition temperature of 350°C or higher, 375°C or higher, 400°C or higher, 450°C or higher, or 500°C or higher. [Invention 1031] A laminate according to any of the present invention 1024 to 1030, wherein at least one of the adhesive layers has a glass transition temperature or melting point of 100°C or higher, 150°C or higher, 200°C or higher, 225°C or higher, 250°C or higher, or 275°C or higher. [Invention 1032] A laminate according to any of invention 1024 to 1031, wherein at least one of the adhesive layers has a thickness of 0.3 to 5 mils, 0.3 to 3.0 mils, 0.3 to 2.0 mils, 0.3 to 1.2 mils, or 0.75 to 1.25 mils. [Invention 1033] The electrical insulating layer includes two or more electrical insulating layers, In the electrical insulating layer, there is no conductive layer placed between adjacent layers. A laminate according to any of the inventions 1001 to 1032. [Invention 1034] A laminate according to any of the present invention 1001 to 1033, having a thickness of 5.0 mil to 100 mil, 5.0 mil to 75 mil, 5.0 mil to 50 mil, or 5.0 mil to 30 mil. [Invention 1035] A laminate according to any of the present invention 1001 to 1034, wherein a part of the front surface of the laminate is arranged in a roll shape so as to face a part of the rear surface of the laminate. [Invention 1036] A laminate according to any of the present invention 1001 to 1035, having a dielectric constant of 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less, or 1.6 or less at 10 GHz. [Invention 1037] A laminate according to the present invention 1036, wherein the dielectric constant is 1.75 or less. [Invention 1038] A laminate according to any of the present invention 1001 to 1037, having a dielectric loss tangent of 0.0025 or less, 0.00225 or less, 0.002 or less, 0.00175 or less, or 0.0015 or less at 10 GHz. [Invention 1039] A laminate according to the present invention 1038, wherein the dielectric loss tangent is 0.002 or less. [Invention 1040] Includes a 1-terra reinforcement layer, Each of the reinforcing layers has a bending stiffness at least 10% greater than the bending stiffness of the conductive layer and the electrical insulating layer, and / or For at least one of the electrical insulating layers, at least one reinforcing layer is at least partially embedded in the polymer aerogel layer such that the Young's modulus of the electrical insulating layer is at least 200 MPa, and / or In at least one of the electrical insulating layers, multiple fibers are dispersed in the polymer aerogel layer such that the Young's modulus of the electrical insulating layer is at least 200 MPa. A laminate according to any of the present invention 1001 to 1039. [Invention 1041] At least one of the reinforcement layers, One or more unidirectional sheets, woven sheets, or nonwoven sheets containing fibers, and / or one or more paper sheets. A laminate of the present invention 1040, including the above. [Invention 1042] A laminate according to any of the present invention 1001 to 1040, which does not contain fibers. [Invention 1043] A laminate according to any of invention 1001 to 1041, For at least one of the front and rear surfaces, a solder mask layer is bonded to the surface such that the solder mask layer covers at least a large portion of the surface, and the solder mask layer contains at least 90% by weight of polymer. A circuit board, including a circuit board. [Invention 1044] A circuit board according to the present invention 1043, wherein the thickness of the solder mask layer is 3.2 mils or less, 1.6 mils or less, or 0.8 mils or less. [Invention 1045] An apparatus comprising a circuit board according to the present invention 1043 or 1044, The circuit board includes an antenna electrically coupled to it, and / or A device that is an electrical amplifier, radar system, or communication system. Some details and other information related to the aforementioned aspects are described below. [Brief explanation of the drawing]

[0029] The following drawings are illustrative and not limiting. For brevity and clarity, not all features of a given structure are always labeled in every drawing in which that structure appears. The same reference number does not necessarily refer to the same structure. Rather, the same reference number may be used to indicate similar features or features with similar functions, just as it may not refer to identical reference numbers.

[0030] [Figure 1] Figure 1A is a top view of a first embodiment of the laminate of the present invention, which includes a polymer aerogel layer positioned between two copper-containing layers. Figure 1B is a cross-sectional side view of the laminate of Figure 1A, obtained along line 1B-1B. [Figure 2] Figure 2A is a cross-sectional side view of a second embodiment of the laminate of the present invention, which includes two polymer aerogel layers positioned between two copper-containing layers. Figure 2B is a cross-sectional side view of a third embodiment of the laminate of the present invention, which includes four polymer aerogel layers positioned between two copper-containing layers. [Figure 3] Figure 3A is a cross-sectional side view of a fourth embodiment of the laminate of the present invention, which includes a reinforcing layer embedded in a polymer aerogel layer. Figure 3B is a cross-sectional side view of a fifth embodiment of the laminate of the present invention, which includes a non-embedded reinforcing layer in addition to the polymer aerogel layer and the copper-containing layer. [Figure 4] Figure 1A is a perspective view of the roll-shaped laminate. [Figure 5A]Figure 5A is a top view of one circuit board of the present invention, including the laminate shown in Figure 1A, in which the copper-containing layer on top of the laminate is etched to define separate conductive paths. Figure 5A omits the solder mask layer of the circuit board. [Figure 5B] Figure 5A is a top view of the circuit board, where the solder mask layer covers at least a large portion of the top surface of the laminate. [Figure 5C] This is a cross-sectional side view of the circuit board shown in Figure 5A, obtained along line 5C-5C in Figure 5B. [Figure 6] This is a schematic diagram of one apparatus of the present invention, including the circuit board shown in Figure 5A which is electrically coupled to the antenna. [Figure 7] This is the distribution of pore diameters for the first non-restrictive aerogel of the present invention. [Figure 8] This is the distribution of pore diameters for the second non-limiting aerogel of the present invention. [Figure 9] This is the distribution of pore diameters for the third non-limiting aerogel of the present invention. [Modes for carrying out the invention]

[0031] Detailed explanation A. Copper-clad laminates, circuit boards, and devices incorporating them. Referring to Figures 1A and 1B, a first embodiment 10a of the laminate of the present invention is shown. The laminate 10a may include one or more conductive layers 14 and one or more electrical insulating layers 18, for example, one or more conductive layers, or any two of any number, such as 1, 2, 3, 4, 5, or 6, and one or more electrical insulating layers, or any two of any number, such as 1, 2, 3, 4, 5, or 6. As shown, the laminate 10a includes two conductive layers 14 and one electrical insulating layer 18 disposed between them. However, in other embodiments, the laminate (e.g., 10b or 10c) may include a plurality of electrical insulating layers 18, for example, two (Figure 2A) or four (Figure 2B) electrical insulating layers.

[0032] For at least one of the opposing front and rear surfaces (22a and 22b) of the laminate (e.g., 10a to 10c), at least a portion (e.g., at least the majority, and at most all) of the surface (e.g., the planar area of ​​the surface) may be defined by one of the conductive layers 14; as shown, substantially all of the front and rear surfaces are defined by the first and second conductive layers, respectively, and all of the electrical insulating layers 18 are located between the first and second conductive layers. In this way, one or more of the conductive layers 14 can be exposed so that circuits can be fabricated from them (e.g., by etching, as described later), and the electrical insulating layers 18 support and insulate the conductive layers. To further facilitate such circuit fabrication, in some embodiments where there are multiple electrical insulating layers 18, no conductive layers 14 are located between adjacent layers of the electrical insulating layers.

[0033] Each of the conductive layers 14 may contain copper to enhance conductivity. For example, each of the conductive layers 14 may contain copper in any one or more of 90% by weight, 91% by weight, 92% by weight, 93% by weight, 94% by weight, 95% by weight, 96% by weight, 97% by weight, 98% by weight, or 99% by weight, or between any two of these values. The thickness 30 of each conductive layer 14 may promote manufacturability and appropriate electrical properties. For example, at least one of the conductive layers 14 (e.g., each) may have a thickness 30 of 30 such that it is less than or equal to any one of the following values: 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0, 0.9, 0.8, 0.7, 0.6, or 0.5 mils, or between any two of these values ​​(e.g., 0.5 to 3.0 mils, e.g., 0.5 to 2 mils, e.g., 0.5 to 0.9 mils, about 1.4 mils, or about 0.7 mils). The surface density of each conductive layer 14 may be 3.0, 2.5, 2.0, 1.5, 1.0, 0.75, 0.50, or 0.25 ounces per square foot (oz / ft). 2 ) less than or equal to any one value, or between any two values ​​(for example, 0.35 to 3.0 oz / ft) 2 For example, 0.35~0.75 oz / ft 2 Or approximately 0.5 oz / ft 2) can be relatively thick (e.g., 1.5 mil or more and / or 1.1 oz / ft). 2 By using a conductive layer 14 with the above surface density, it can be adapted to larger power loads.

[0034] In some aspects, each of the electrical insulation layers 18 may contain a porous material. In certain aspects, the porous material may be an open-cell porous material. In certain other aspects, the porous material may be a closed-cell porous material. In certain aspects, the porous material may be a foam. In certain aspects, the foam may be an organic or silicone foam. Non-limiting examples of organic foams may include polyurethane, polystyrene, polyvinyl chloride, (meth)acrylic polymer, polyamide, polyimide, polyaramid, polyurea, polyester, polyolefin (e.g., polyethylene, polypropylene, ethylene propylene diene monomer (EPDM) foam), polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, polyvinyl acetate, ethyl vinyl alcohol (EVOH), ethylene vinyl acetate (EVA), polymethyl methacrylate, polyacrylate, polycarbonate, polysulfonate, or synthetic rubber foam, or any combination thereof. In certain aspects, the foam may be a polyurethane foam. In certain aspects, the porous material may be an aerogel. In some aspects, each of the electrical insulating layers 18 may include a layer of polymer aerogel. To promote desired dielectric properties (e.g., low dielectric constant and low dielectric loss tangent), each aerogel layer 18 may be relatively thin. For example, the thickness 34 of at least one (e.g., each) aerogel layer 18 may be less than or equal to any one of 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9.0, 8.0, 7.0, 6.0, 5.0, 4.0, or 3.0 mils, or between any two of these values, preferably 12 mils or less (e.g., about 10 mils) or 7.0 mils or less (e.g., about 5.0 mils).In some embodiments, each of the electrical insulating layers 18 has i) a dielectric constant less than or equal to any one of 3, 2.75, 2.5, 2.25, 2, 1.75, 1.6, 1.4, 1.3, 1.2, and 1.1 at 10 GHz, or between any two of these values; and / or a dielectric loss tangent less than or equal to any one of 0.005, 0.004, 0.003, 0.0025, 0.00225, 0.002, 0.00175, 0.0015, 0.00125, 0.001, 0.00075, and 0.0005 at 10 GHz, or between any two of these values.

[0035] Each polymer aerogel layer 18 may have micropores, mesopores, and / or macropores. Micropores, mesopores, and / or macropores (e.g., micropores, mesopores, micropores and mesopores, or macropores) may occupy 10%, 25%, 50%, 75%, or 95% of the pore volume of each aerogel layer 18, or any one of these values. The average pore volume of each aerogel layer 18 may be 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 800, 1,000, 2,000, 3,000, 4,000, or 5,000 nm, or any two of these values.

[0036] Each of the aerogel layers 18 may also be heat-resistant, such that the laminate can withstand heating during circuit board manufacturing (e.g., during soldering) and during use (e.g., from heat generated by electricity flowing through the laminate). For example, the decomposition temperature of at least one of the aerogel layers 18 (e.g., each) may be greater than or equal to any one of 400, 425, 450, 475, 500, 525, 550, 575, or 600°C, or between any two of these values ​​(e.g., greater than or equal to 450°C). The materials and manufacturing processes for the polymer aerogel layers are described in sections B and C below.

[0037] In some aspects, each of the electrical insulation layers 18 may include fibers without the porous material of the present invention. In other aspects, each of the electrical insulation layers 18 may include a combination of the porous material of the present invention and fibers (e.g., fibers dispersed or aligned within the porous material). The fibers may be natural, synthetic, semi-synthetic fibers, or a combination thereof. The fibers may include plant, woody, animal, mineral, biological fibers, or a combination thereof. In some specific examples, the fibers may include rayon, bamboo, diacetate, triacetate fibers, polyester fibers, aramid fibers, or a combination thereof. In some embodiments, the fibers may include metal fibers, carbon fibers, carbide fibers, glass fibers, mineral fibers, basalt fibers, or a combination thereof. In some embodiments, the fibers may include thermoplastic polymer fibers, thermosetting polymer fibers, or a combination thereof. Non-limiting examples of thermoplastic fibers include polyethylene terephthalate (PET), polymers of the polycarbonate (PC) family, polybutylene terephthalate (PBT), poly(1,4-cyclohexylidenecyclohexane-1,4-dicarboxylate) (PCCD), glycol-modified polycyclohexyl terephthalate (PCTG), poly(phenylene oxide) (PPO), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polymethyl methacrylate (PMMA), polyethyleneimine, or polyethere. This includes fibers made from luimide (PEI) and its derivatives, thermoplastic elastomers (TPE), terephthalic acid (TPA) elastomers, poly(cyclohexanedimethylene terephthalate) (PCT), polyethylene naphthalate (PEN), polyamide (PA), polysulfone sulfonate (PSS), polysulfone sulfonate, polyether ether ketone (PEEK), polyether ketone ketone (PEKK), acrylonitrile butyldiene styrene (ABS), polyphenylene sulfide (PPS), copolymers thereof, or mixtures thereof.Non-limiting examples of thermosetting fibers include fibers of unsaturated polyester resins, polyurethanes, polyoxybenzylmethylene glycol anhydride (e.g., Bakelite), urea formaldehyde, diallyl phthalate, epoxy resins, epoxy vinyl esters, polyimides, cyanate esters of polycyanurates, dicyclopentadienes, phenols, benzoxazines, copolymers thereof, or mixtures thereof. In some embodiments, the fibers are polyaramids, polyimides, polybenzoxazoles, polyurethanes, or mixtures thereof. In some embodiments, the fibers are vinylon. In some embodiments, the fibers are polyester fibers. In some embodiments, the fibers are nonwoven fabrics. In some embodiments, the fibers form a fiber matrix. In some embodiments, the fibers are 5 μm thick. 2 ~40,000 μm 2 The average filament cross-sectional area and average length are 20 mm to 100 mm. In some embodiments, the cross-sectional area is 5, 10, 15, 20, 25, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500 μm. 2, or any two of those values. In some embodiments, the fibers have an average length of about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, 2000, 3000, 4000, 5000 mm, or any two of those values. Bundles of various types of fibers can be used depending on the intended application of the internally reinforced aerogel. For example, the bundle may be of carbon fiber or ceramic fiber, or of fiber that is a precursor of carbon or ceramic, glass fiber, aramid fiber, or a mixture of different types of fibers. The bundle may contain any number of fibers. For example, a bundle may contain 400, 750, 800, 1375, 1000, 1500, 3000, 6000, 12000, 24000, 50000, or 60000 filaments. The fibers may have filament diameters of 5–24 microns, 10–20 microns, or 12–15 microns, or any range in between, or filament diameters of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 microns, or any value in between. The fibers in a bundle of fibers may be 7 μm in diameter. 2 ~800μm 2 The average filament cross-sectional area may be such that the average diameter of the circular fibers is 3 to 30 microns. In some embodiments, the fiber matrix includes felt, padding, nonwoven fabric, or mat.

[0038] The laminate may also include one or more adhesive layers 26, e.g., any one or more of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, or any two adhesive layers, for bonding the other layers of the laminate to each other. Each of the adhesive layers 26 may be placed between adjacent layers of the other laminate layers (e.g., conductive layer 14 and electrically insulating layer 18). Bonding can be achieved by stacking the layers (e.g., 14, 18, 26) and optionally applying heat and / or pressure (e.g., using a press) to the stack so that its temperature exceeds the glass transition temperature of the adhesive layers 26.

[0039] The adhesive layer 26 may have a composition that reduces the risk of delamination through heat resistance, etc. For example, at least one of the adhesive layers 26 (e.g., each) may have a decomposition temperature of any one value or greater than 350, 375, 400, 425, 450, or 500°C, or between any two values. In addition, at least one of the adhesive layers 26 (e.g., each) may have a glass transition temperature or melting point of any one value or greater than 100, 150, 175, 200, 225, 250, or 275°C, or between any two values. The adhesive layer 26 can also promote a low dielectric constant and dielectric loss tangent for the laminate. For example, measured at 10 GHz, at least one (e.g., each) of the adhesive layers 26 may have a dielectric constant less than or equal to any one of 3.5, 3.25, 3.0, 2.75, 2.5, or 2.25, or between any two values ​​(e.g., less than or equal to 3.0), and / or a dielectric loss tangent less than or equal to any one of 0.0040, 0.0035, 0.0030, 0.0025, 0.0020, or 0.0015, or between any two values ​​(e.g., less than or equal to 0.00375). Exemplary adhesives suitable for the adhesive layers 26 include fluoropolymer films, polyimide films, and B-stage epoxy. The adhesive for the adhesive layer 26 may be a commercially available adhesive such as DuPont® FEP Film, Pyralux® HT, and Pyralux® GPL, as well as Toyochem Co., LTD. (Tokyo, Japan) TSU510S-A and DuPont® Teflon FEP. The thickness 38 of at least one (e.g., each) of the adhesive layer 26 may be less than or equal to any one of 5.0, 4.0, 3.0, 2.0, 1.25, 1.0, 0.75, 0.60, 0.50, 0.40, or 0.30 mils, or between any two of these values ​​(e.g., 0.3 to 0.7 mils, e.g., about 0.5 mils), which can promote adhesion while promoting the desired dielectric properties.

[0040] The laminate may have a relatively thin total thickness 42 (e.g., measured between the front and back surfaces (22a and 22b)) suitable for use in circuit boards (e.g., to promote low dielectric constant and dielectric loss tangent). For example, the thickness 42 may be less than or equal to any one of 100, 75, 50, 40, 30, or 20 mils, or between any two of those values ​​(e.g., 5 to 30 mils).

[0041] The laminate may have dielectric properties suitable for use in high-frequency applications (e.g., signal frequencies of 10 to 300 GHz). For example, the laminate may have an ultra-low dielectric constant, such as being less than or equal to any one of 2.0, 1.9, 1.8, 1.7, or 1.6 at 10 GHz, or between any two values ​​(e.g., less than or equal to 1.75), allowing electrical signals to propagate through the laminate at relatively high speeds. In addition, the laminate may have a low dielectric loss tangent to reduce dielectric loss, such as being less than or equal to any one of 0.0025, 0.00225, 0.002, 0.00175, or 0.0015 at 10 GHz, or between any two values ​​(e.g., less than or equal to 0.002).

[0042] In some embodiments, the laminate may include reinforcement, such as multiple fibers, to increase strength and / or stiffness (e.g., for rigid circuit board applications). Referring, for example, to Figures 3A and 3B, are laminates 10d and 10e, which are substantially the same as laminate 10a, except that each includes one or more reinforcing layers 46, e.g., one or more of any number of 1, 2, 3, 4, 5, 6, 7, or 8, or any two or more reinforcing layers. At least one of the reinforcing layers 46 (e.g., each) may include one or more sheets. At least one of the sheets (e.g., each) may optionally include unidirectional sheets, woven sheets, and / or nonwoven sheets, containing fibers dispersed in a thermoplastic or thermosetting resin (e.g., a resin with a different structure (e.g., non-porous) or composition from the aerogel layer 18). The sheets of the reinforcing layer 46 may also be substantially fiberless (e.g., polymer films, such as fluoropolymer films). When multiple sheets are included, the reinforcing layer 46 may be a reinforced laminate. In addition, or alternatively, at least one of the reinforcing layers 46 (e.g., each) may include a paper sheet, optionally containing cellulose fibers, vinylon fibers, polyester fibers, polyolefin fibers, and / or polypropylene fibers. Suitable papers for the reinforcing layer 46 are commercially available from Hirose Paper Mfg. Co. (Kochi, Japan) or Hirose Paper North America (Macon, Georgia, USA).

[0043] As shown, for at least one of the aerogel layers 18, at least one of the reinforcing layers 46 is embedded in the aerogel layer (Figure 3A). As shown, while a single reinforcing layer 46 is embedded in the aerogel layer 18, in other embodiments, multiple reinforcing layers (e.g., any one or more of 2, 3, 4, 5, or 6, or between two) can be embedded in the aerogel layer. In addition, or alternatively, one or more reinforcing layers 46 do not need to be embedded in one of the aerogel layers 18, but can be bonded to other laminate layers via one or more adhesive layers 26 (e.g., they can be placed between adjacent layers of adhesive layers). The reinforcing or supporting layers 46 can be embedded in or bonded to the aerogel layer 18 as described in Section C.

[0044] Furthermore, as shown, the laminates 10d and 10e are reinforced with reinforcing layers 46, but in some embodiments, at least one of the aerogel layers 18 (e.g., each) may optionally contain reinforcing fibers dispersed throughout the aerogel layer (e.g., discontinuous or engraved, not arranged in a sheet) such that the volume of fibers is at least one of 0.1%, 10%, 20%, 30%, 40%, or 50% of the volume of the polymer aerogel layer, or between any two of these values. However, in some embodiments, the laminate does not contain fibers (e.g., to increase flexibility).

[0045] Suitable fibers include glass fibers, carbon fibers, aramid fibers, thermoplastic fibers, thermosetting fibers, ceramic fibers, basalt fibers, rock wool fibers, steel fibers, and cellulose fibers. The average filament cross-sectional area of ​​the fibers used for reinforcement is 7, 15, 30, 60, 100, 200, 300, 400, 500, 600, 700, or 800 μm. 2It can be any one or more of the following values, or between any two values; for example, for a fiber having a circular cross-section, the average diameter of the fiber can be any one or more of the following values, or between any two values ​​(e.g., 5-24 μm, e.g., 10-20 μm or 12-15 μm).

[0046] Non-limiting examples of thermoplastic polymers that can be used as a material in which fibers are dispersed in the reinforcing layer 46 and / or for polymer reinforcing fibers include polyethylene terephthalate (PET), polycarbonate (PC), polybutylene terephthalate (PBT), poly(1,4-cyclohexylidenecyclohexane-1,4-dicarboxylate) (PCCD), glycol-modified polycyclohexyl terephthalate (PCTG), poly(phenylene oxide) (PPO), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polymethyl methacrylate (PMMA), polyethyleneimine, or polyetheric acid. This includes polyamides (PEI) and their derivatives, thermoplastic elastomers (TPE), terephthalic acid (TPA) elastomers, poly(cyclohexanedimethylene terephthalate) (PCT), polyethylene naphthalate (PEN), polyamides (PA), polysulfone sulfonates (PSS), polysulfone sulfonates, polyether ether ketones (PEEK), polyether ketone ketones (PEKK), acrylonitrile butyldiene styrene (ABS), polyphenylene sulfide (PPS), copolymers thereof, polyesters or derivatives thereof, polyamides or derivatives thereof (e.g., nylon), or mixtures thereof.

[0047] Non-limiting examples of thermoplastic fibers that can be used as materials in which fibers are dispersed in the reinforcing layer 46 and / or for polymer reinforcing fibers include unsaturated polyester resins, polyurethanes, polyoxybenzylmethylene glycol anhydride (e.g., Bakelite), urea formaldehyde, diallyl phthalate, epoxy resins, epoxy vinyl esters, polyimides, cyanate esters of polycyanurates, dicyclopentadienes, phenols, benzoxazines, copolymers thereof, or mixtures thereof.

[0048] Such reinforcement can increase the strength and stiffness of the laminate. For example, each of the electrically insulating layers 18 reinforced with an aerogel layer (e.g., by one or more embedded sheets and / or fiber reinforcement dispersed throughout the aerogel) may have a tensile strength of any one value greater than or equal to 5, 10, 15, 20, or 25 MPa, or between any two values, and / or a Young's modulus of any one value greater than or equal to 200, 225, 250, 275, 300, 325, or 350 MPa, or between any two values. Each of the reinforcing layers 46 may also be stiffer than the other laminate layers; for example, the bending stiffness of each reinforcing layer may be greater than the bending stiffness of the conductive layer 14 and the electrically insulating layer 18, respectively, by any one value greater than or equal to 10%, 20%, 30%, or 40%, or between any two values.

[0049] A further description of appropriate reinforcement of the aerogel layer 18 is provided in U.S. Patent No. 10,500,557 by Sakaguchi et al., which is incorporated herein by reference in its entirety.

[0050] The laminate (e.g., 10a-10e) can be rigid or flexible. For example, referring to Figure 4, the laminate (whether reinforced as described above) can be placed in a roll shape 48 having an inner diameter 50 of any one value less than or equal to 10 cm, 8 cm, 5 cm, 4 cm, 2 cm, or 1 cm, or between any two of those values, without undergoing permanent deformation. Such flexibility may be provided by the materials of the conductive layer, aerogel layer, and other (if any) layers of the laminate, and / or the relatively thin thickness of those layers (e.g., as described above), even if not to the level of this example. In the case of the roll shape 48, a portion of the front surface 22a of the laminate may face a portion of the rear surface 22b. The laminate may have a protective film 52 detachably placed on at least one of its front and rear surfaces (22a and 22b) (to protect one or more of the conductive layers 14). The protective film 52 can be removed from the laminate, for example, by peeling it off. Such a protective film does not form part of the laminate.

[0051] Such flexible laminates may be suitable for use in flexible circuit boards. However, in other embodiments, the laminate may have higher rigidity (e.g., so that it cannot be placed in such a roll shape without undergoing permanent deformation and / or breakage), which may be provided by the aforementioned reinforcement. Such laminates may be suitable for use in rigid circuit boards.

[0052] Some of the laminates of the present invention (e.g., 10a to 10e) can be incorporated into a circuit board. For example, referring to Figures 5A to 5C, a circuit board 54 including laminate 10a is shown. As shown, at least one of the conductive layers 14 defining one portion of the front and rear surfaces (22a and 22b) (e.g., each) can be etched such that the conductive layer defines one or more conductive wires 56. Etching can remove material from the conductive layer 14; as a result, the etched layer can define a smaller surface area of ​​the front and / or rear surfaces (22a and 22b) than that defined by the polymer aerogel layer 18 and / or adhesive layer 26 (e.g., less than any one value of 90%, 80%, 70%, 60%, 50%, or 40%, or between any two values) (e.g., where such surface area is measured as a planar area).

[0053] The circuit board 54 may include one or more solder mask layers 58, each bonded to one of the front and rear surfaces (22a and 22b) respectively, such that the solder mask layer covers at least a large portion of the surface (Figures 5B and 5C). Each of the solder mask layers 58 can protect the outermost conductive layer 14 (e.g., from corrosion, damage, and / or short circuits). For example, each solder mask layer 58 may contain a polymer (e.g., any of the aforementioned) such that the polymer is optionally contained in any one or more of 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%, or between any two of these values. To promote such protection while maintaining proper manufacturability and / or electrical properties, the thickness 62 of each solder mask layer 58 may be less than or equal to any one of 3.2, 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, or 0.8 mils, or between any two of those values ​​(e.g., 0.8 to 3.2 mils). Each solder mask layer 58 may cover a portion smaller than all of the surface to which the solder mask layer is bonded (e.g., 22a or 22b) such that at least a portion of the conductive layer 14 is exposed (e.g., so that components can be electrically connected to it) (Figure 5B).

[0054] Some of the circuit boards of the present invention (e.g., 54) can be incorporated into devices (e.g., 66) used for high-frequency (e.g., 10-300 GHz) applications. For example, referring to Figure 6, the device 66 includes a circuit board 54 and an antenna 70 electrically coupled to the circuit board. As shown, the device 66 is a communication system (e.g., used in satellites, high-speed routers and servers, spacecraft, mobile phones, mobile phone base stations, etc.). The device 66 could also be another device used in high-frequency applications, such as an electrical amplifier and / or radar system.

[0055] B. Materials for polymer aerogel layers The polymer aerogel layer may contain organic materials, inorganic materials, or mixtures thereof. Organic aerogels can be made from polyacrylate, polystyrene, polyacrylonitrile, polyurethane, polyurea, polyimide, polyamide, polyaramid, polyfurfural alcohol, phenol furfuryl alcohol, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, polyacrylamide, various epoxies, agar, agarose, etc. In certain embodiments, the aerogel is a polyimide aerogel.

[0056] Polyimides are a type of polymer with many desirable properties. Polyimide polymers contain a nitrogen atom in their polymer backbone, where the nitrogen atom is linked to two carbonyl carbons so that it is somewhat stabilized by adjacent carbonyl groups. The carbonyl group contains a carbon atom called the carbonyl carbon, which is double-bonded to an oxygen atom. Since polyimide polymers are usually produced using two different types of monomers, polyimides are typically considered AA-BB type polymers. Polyimides can also be prepared from AB type monomers. For example, aminodicarboxylic acid monomers can be polymerized to form AB type polyimides. Monoamines and / or monoanhydrides can be used as end-capping agents as needed.

[0057] One class of polyimide monomers is typically diamines, or diamine monomers. Diamine monomers may also be diisocyanates, and it should be understood that isocyanates may be substituted for amines as appropriate in this description. As is well known to those skilled in the art, there are other types of monomers that can be used instead of diamine monomers. These other types of monomers are called acid monomers and are typically in the form of dianhydrides. In this description, the term “diacid monomer” is defined to include dianhydrides, tetraesters, diesteric acids, tetracarboxylic acids, or trimethylsilyl esters, all of which can react with diamines to produce polyimide polymers. Dianhydrides should be understood to be tetraesters, diesteric acids, tetracarboxylic acids, or trimethylsilyl esters, which may be substituted as appropriate. As is well known to those skilled in the art, there are other types of monomers that can be used instead of diacid monomers.

[0058] Since one diamino acid monomer has two anhydride groups, different diamino monomers can react with each anhydride group, and therefore a diamino acid monomer can be located between two different diamino monomers. A diamine monomer contains two amine functional groups; therefore, after the first amine functional group is bonded to one diamino acid monomer, the second amine functional group is still available to bond to another diamino acid monomer, which then bonds to another diamine monomer, and so on. In this way, a polymer skeleton is formed. The resulting polycondensation reaction product forms a polyamic acid.

[0059] Polyimide polymers are typically formed from two different types of monomers, and it is possible to mix different variants of each type of monomer. Therefore, one, two, or more diacid monomers can be included in the reaction vessel, as can one, two, or more diamino monomers. When long polymer chains are desired, the total molar amount of diacid monomers is maintained to be approximately the same as the total molar amount of diamino monomers. Because multiple types of diamines or diacids can be used, the monomer composition of each polymer chain can be varied to produce polyimides with different properties. For example, a single diamine monomer AA can be reacted with two diacid comonomers B1B1 and B2B2 to produce a polyimide of the general formula (AA-B1B1). x -(AA-B2B2) y A polymer chain of the following can be formed, where x and y are determined by the relative incorporation of B1B1 and B2B2 into the polymer backbone. Alternatively, the diamine comonomers A1A1 and A2A2 can be reacted with a single diacid monomer BB to form a polymer of the general formula (A1A1-BB). x -(A2A2-BB) y A polymer chain of the general formula (A1A1-B1B1) can be formed by reacting two diamine comonomers A1A1 and A2A2 with two diacid comonomers B1B1 and B2B2. w -(A1A1-B2B2) x -(A2A2-B1B1) y -(A2A2-B2B2) z Polymer chains can be formed, where w, x, y, and z are determined by the relative incorporation of A1A1-B1B1, A1A1-B2B2, A2A2-B1B1, and A2A2-B2B2 into the polymer backbone. Three or more diacid comonomers and / or three or more diamine comonomers can also be used. Thus, one or more diamine monomers can be polymerized with one or more diacids, and the general formula of the polymer is determined by varying the amount and type of monomers used.

[0060] There are many examples of monomers that can be used to prepare polymer aerogels containing polyamic acid amide polymers. In some embodiments, the diamine monomer is a substituted or unsubstituted aromatic diamine, a substituted or unsubstituted alkyl diamine, or a diamine that may contain both aromatic and alkyl functional groups. A non-restrictive list of possible diamine monomers includes 4,4'-oxydianiline (ODA), 3,4'-oxydianiline, 3,3'-oxydianiline, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, diaminobenzanilide, 3,5-diaminobenzoic acid, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 1,3-bis-(4-aminophenoxy)benzene, 1,3-bis-(3-aminophenoxy)benzene, 1,4-bis-(4-aminophenoxy)benzene, 1,4-bis-(3-aminophenoxy)benzene, 2,2-bis[4-( 4-aminophenoxy)phenyl]-hexafluoropropane, 2,2-bis(3-aminophenyl)-1,1,1,3,3,3-hexafluoropropane, 4,4'-isopropylidenedianiline, 1-(4-aminophenoxy)-3-(3-aminophenoxy)benzene, 1-(4-aminophenoxy)-4-(3-aminophenoxy)benzene, bis-[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(3-aminophenoxy)phenyl]sulfone, bis(4-[4-aminophenoxy]phenyl) ether, 2,2'-bis-(4-aminophenyl)-hexafluoropropane (6F-diamine), 2,2'-bis-(4-phenoxyaniline)isopropylidene, meta-phenylenediamine, para-phenylenediamine, 1,2-diaminobenzene, 4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,6-diaminopyridine, bis(3-aminophenyl)diethylsilane, 4,4'-diaminodiphenyldiethylsilane, benzidine, dichlorobenzidine, 3,3'-dimethoxybenzidine, 4,4'-Diaminobenzophenone, N,N-bis(4-aminophenyl)-n-butylamine, N,N-bis(4-aminophenyl)methylamine, 1,5-diaminonaphthalene, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4-aminophenyl-3-aminobenzoate, N,N-bis(4-aminophenyl)aniline, bis(p-beta-amino-t-butylphenyl)ether, p-bis-2-(2-methyl-4-aminopentyl)benzene, p-bis(1,1-dimethyl-5-aminopentyl)benzene, 1,3-bis(4-aminophenoxy)benzene, m-xylenediamine, p-xylenediamine, 4,4'-diaminodiphenyl etherphosphine oxide, 4,4'-diaminodiphenyl N-methylamine, 4,4'- Diaminodiphenyl N-phenylamine, amino-terminated polydimethylsiloxane, amino-terminated polypropylene oxide, amino-terminated polybutylene oxide, 4,4'-methylenebis(2-methylcyclohexylamine), 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, and 4,4'-methylenebisbenzeneamine, 2,2'-dimethylbenzidine (also known as 4,4'-diamino-2,2'-dimethylbiphenyl (DMB)), bisaniline-p-xylidene, 4,4'-bis(4-aminophenoxy)biphenyl, 3,3'-bis(4 This includes aminophenoxy)biphenyl, 4,4'-(1,4-phenylenediisopropylidene)bisaniline, and 4,4'-(1,3-phenylenediisopropylidene)bisaniline, or combinations thereof. In certain embodiments, the diamine monomer is ODA, 2,2'-dimethylbenzidine, or both.

[0061] An unrestricted list of possible dianhydride ("diacid") monomers includes hydroquinone dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), pyromellitic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 4,4'-(4,4'-isopropylidene diphenoxy)bis(phthalic acid anhydride), 2,2-bis(3, 4-Dicarboxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid anhydride, bis(3,4-dicarboxyphenyl) sulfoxide dianhydride, polysiloxane-containing dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 2,3,2',3'-benzophenonetetracarboxylic acid dianhydride, naphthalene-2,3,6,7-tetracarboxylic acid dianhydride, naphthalene-1,4,5,8-tetracarboxylic acid dianhydride, 4, 4'-Oxydiphthalic acid dianhydride, 3,3',4,4'-biphenylsulfonetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, bis(3,4-dicarboxyphenyl)sulfide dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, 2,6-dichloronaphthalene-1,4 These include ,5,8-tetracarboxylic dianhydride, 2,7-dichloronaptalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, phenanthrene, 8,9,10-tetracarboxylate dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, and thiophene-2,3,4,5-tetracarboxylic dianhydride. In certain embodiments, the dianhydride monomer is BPDA, PMDA, or both.

[0062] In some cases, the molar ratio of the anhydride to the total diamine is 0.4:1–1.6:1, 0.5:1–1.5:1, 0.6:1–1.4:1, 0.7:1–1.3:1, or in particular 0.8:1–1.2:1. In further cases, the molar ratio of the dianhydride to the polyfunctional amine (e.g., triamine) is 2:1–140:1, 3:1–130:1, 4:1–120:1, 5:1–110:1, 6:1–100:1, 7:1–90:1, or in particular 8:1–80:1. Monoanhydride groups can also be used. Non-limiting examples of monoanhydride groups include 4-amino-1,8-naphthalic anhydride, endo-bicyclo[2.2.2]octa-5-ene-2,3-dicarboxylic acid anhydride, citraconic acid anhydride, trans-1,2-cyclohexanedicarboxylic acid anhydride, 3,6-dichlorophthalic acid anhydride, 4,5-dichlorophthalic acid anhydride, tetrachlorophthalic acid anhydride, 3,6-difluorophthalic acid anhydride, 4,5-difluorophthalic acid anhydride, tetrafluorophthalic acid anhydride, maleic acid anhydride, 1-cyclopentene-1,2-dicarboxylic acid anhydride, and 2,2-dimethylglutaric acid anhydride. This includes 3,3-dimethylglutaric anhydride, 2,3-dimethylmaleic anhydride, 2,2-dimethylsuccinic anhydride, 2,3-diphenylmaleic anhydride, phthalic anhydride, 3-methylglutaric anhydride, methylsuccinic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, 2,3-pyrazinedicarboxylic acid anhydride, or 3,4-pyridinedicarboxylic acid anhydride. In particular, one anhydride group may be a phthalic anhydride.

[0063] In another embodiment, the polymer composition used to prepare the polymer aerogel layer comprises a polyfunctional amine monomer having at least three primary amine functional groups. The polyfunctional amine may be a substituted or unsubstituted aliphatic polyfunctional amine, a substituted or unsubstituted aromatic polyfunctional amine, or a polyfunctional amine comprising a combination of an aliphatic group and two aromatic groups, or a combination of an aromatic group and two aliphatic groups.A non-restrictive list of possible polyfunctional amines includes propane-1,2,3-triamine, 2-aminomethylpropane-1,3-diamine, 3-(2-aminoethyl)pentane-1,5-diamine, bis(hexamethylene)triamine, N',N'-bis(2-aminoethyl)ethane-1,2-diamine, N',N'-bis(3-aminopropyl)propane-1,3-diamine, 4-(3-aminopropyl)heptane-1,7-diamine, N',N'-bis(6-A Minohexyl)hexane-1,6-diamine, benzene-1,3,5-triamine, cyclohexane-1,3,5-triamine, melamine, N-2-dimethyl-1,2,3-propanetriamine, diethylenetriamine, 1-methyl or 1-ethyl or 1-propyl or 1-benzyl-substituted diethylenetriamine, 1,2-dibenzyldiethylenetriamine, lauryldiethylenetriamine, N-(2-hydroxypropyl)diethylenetriamine N,N-bis(l-methylheptyl)-N-2-dimethyl-1,2,3-propanetriamine, 2,4,6-tris(4-(4-aminophenoxy)phenyl)pyridine, N,N-dibutyl-N-2-dimethyl-l,2,3-propanetriamine, 4,4'-(2-(4-aminobenzyl)propane-1,3-diyl)dianiline, 4-((bis(4-aminobenzyl)amino)methyl)aniline, 4-(2-(bis(4-aminophenethyl)amino)eth These include 1,3,5-tris(4-aminophenethyl)pentane-1,5-diyl)dianiline, 1,3,5-tris(4-aminophenoxy)benzene (TAPOB), 4,4',4''-methanetriyltrianiline, N,N,N',N'-tetrakis(4-aminophenyl)-1,4-phenylenediamine, polyoxypropylene triamines, octa(aminophenyl) polyhedral oligomer silsesquioxanes, or combinations thereof. A specific example of a polyoxypropylene triamine is JEFFAMINE® T-403 from Huntsman Corporation, The Woodlands, TX, USA. In certain embodiments, the aromatic polyfunctional amine may be 1,3,5-tris(4-aminophenoxy)benzene or 4,4',4''-methanetriyltrianiline.In some embodiments, the polyfunctional amine comprises three primary amine groups and one or more secondary and / or tertiary amine groups, for example, N',N'-bis(4-aminophenyl)benzene-1,4-diamine.

[0064] Non-limiting examples of capping agents or groups include those derived from reagents, particularly amines, maleimides, nadiimides, acetylenes, biphenylenes, norbornene, cycloalkyls, and N-propargyls, as well as reagents containing 5-norbornene-2,3-dicarboxylic acid anhydride (nadic anhydride, Na), methylnadic anhydride, hexachloronadic anhydride, cis-4-cyclohexene-1,2-dicarboxylic acid anhydride, 4-amino-N-propargylphthalimide, 4-ethynylphthalic anhydride, and maleic anhydride.

[0065] The characteristics or properties of the final polymer are greatly influenced by the selection of monomers used to produce the polymer. Factors to consider when selecting monomers include the properties of the final polymer, such as flexibility, thermal stability, coefficient of thermal expansion (CTE), coefficient of water absorption expansion (CHE), and any other properties that are particularly desirable, as well as cost. Often, certain important properties of the polymer can be identified for a particular application. Other properties of the polymer may be less important or may have a wide range of acceptable values; therefore, many different monomer combinations can be used.

[0066] In some examples, the polymer backbone may contain further substituents. Substituents (e.g., oligomers, functional groups, etc.) may be directly bonded to the backbone or linked to it through linking groups (e.g., tethers or flexible tethers). In other embodiments, compounds or particles may be incorporated into the polyimide structure (e.g., by mixing and / or encapsulation) without covalent bonding to the polyimide structure. In some examples, the incorporation of compounds or particles may be carried out during a polyamic reaction step. In some examples, particles may aggregate, thereby producing a polyimide having domains containing different concentrations of non-covalently bonded compounds or particles.

[0067] Certain properties of polyimides can be influenced by incorporating specific compounds into them. Monomer selection is one way to influence specific properties. Another way to influence properties is by adding compounds or property-modifying molecules to the polyimide.

[0068] C. Preparation of polymer aerogel layers Polymer aerogel films that can be used in at least some of the laminates of the present invention are commercially available. Non-limiting examples of such films include Blueshift AeroZero® rolled thin films (available from Blueshift Materials, Inc. (Spencer, Massachusetts)) and Airloy® films (available from Aerogel Technologies, LLC), with Blueshift AeroZero® rolled thin films being preferred in some aspects.

[0069] Furthermore, in addition to the processes described later, polymer aerogels (such as films, stock shapes, or monoliths) can be prepared using the methods described in International Publication No. 2014 / 189560 by Rodman et al., No. 2017 / 07888 by Sakaguchi et al., No. 2018 / 078512 by Yang et al., No. 2018 / 140804 by Sakaguchi et al., and No. 2019 / 006184 by Irvin et al., International Application PCT / US2019 / 029191 by Ejaz et al., U.S. Patent Application Publication No. 2017 / 0121483 by Poe et al., and / or U.S. Patent No. 9,963,571 by Sakaguchi et al., all of which are incorporated herein by reference in their entirety.

[0070] The following provides non-limiting steps that can be used to produce a polymer aerogel layer suitable for use in the laminate of the present invention. These steps may include (1) preparation of the polymer gel, (2) optional solvent exchange, (3) drying the polymer solution to form an aerogel, and (4) bonding the polymer aerogel film onto a substrate.

[0071] 1. Formation of polymer gel The first stage in the synthesis of aerogels may be the synthesis of a polymerized gel. For example, if a polyimide aerogel is desired, at least one acid monomer can be reacted with at least one diamino monomer in a reaction solvent to produce a polyamic acid. As mentioned above, many acid monomers and diamino monomers may be used to synthesize polyamic acids. In one aspect, the polyamic acid is brought into contact with an imidation catalyst in the presence of a chemical dehydrating agent to produce a polymerized polyimide gel via an imidation reaction. "Imidation" is defined as the conversion of a polyimide precursor to imide. Any imidation catalyst suitable for driving the conversion of the polyimide precursor to the polyimide state is appropriate. Non-limiting examples of chemical imidation catalysts include pyridine, methylpyridine, quinoline, isoquinoline, 1,8-diazabicyclo[5.4.0]undeca-7-ene (DBU), triethylenediamine, lutidine, N-methylmorpholine, triethylamine, tripropylamine, tributylamine, other trialkylamines, 2-methylimidazole, 2-ethyl-4-methylimidazole, imidazole, other imidazoles, and combinations thereof. Any dehydrating agent suitable for use in the formation of imide rings from amic acid precursors is suitable for use in the methods of the present invention. Preferred dehydrating agents include at least one compound selected from the group consisting of acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride, phosphorus trichloride, and dicyclohexylcarbodiimide.

[0072] In one aspect of the present invention, one or more diamino monomers and one or more polyfunctional amine monomers are pre-mixed in one or more solvents, and then one or more dianhydrides (e.g., diacid monomers) are added sequentially in small amounts at predetermined time increments while monitoring the viscosity. The desired viscosity of the polymerization solution may be in the range of 50 to 20,000 cP, or particularly 500 to 5,000 cP. Non-crosslinked aerogels can be prepared by carrying out the reaction using the gradual addition of dianhydrides while monitoring the viscosity. For example, a triamine monomer (23 equivalents) can be added to the solvent to obtain a 0.0081 molar solution. A first diamine monomer (280 equivalents) can be added to the solution, followed by a second diamine monomer (280 equivalents). Next, dianhydrides (552 equivalents in total) can be added sequentially in small amounts at predetermined time increments while monitoring the viscosity. Dianhydrides can be added until the viscosity reaches 1,000 to 1,500 cP. For example, the first part of the dianhydride can be added, the reaction can be stirred (e.g., for 20 minutes), the second part of the dianhydride can be added, and then a sample of the reaction mixture can be analyzed for viscosity. After stirring for a further time (e.g., 20 minutes), the third part of the dianhydride can be added, and a sample can be taken for viscosity analysis. After stirring for a desired period (e.g., 10 to 12 hours), one anhydride (96 equivalents) can be added. After reaching the target viscosity, the reaction mixture can be stirred for a desired period (e.g., 10 to 12 hours) or until the reaction is considered complete.

[0073] The reaction temperature for gel formation can be determined by routine experimentation depending on the starting materials. In a preferred embodiment, the temperature may be one or more of any one of 15°C, 20°C, 30°C, 35°C, 40°C, and 45°C, or between any two of these values. After a desired time (e.g., about 2 hours), the product can be isolated (e.g., filtered), and then nitrogen-containing hydrocarbons (828 equivalents) and a dehydrating agent (1214 equivalents) can be added. The addition of nitrogen-containing hydrocarbons and / or dehydrating agents can be done at any temperature. In some embodiments, nitrogen-containing hydrocarbons and / or dehydrating agents are added to the solution at 20°C to 28°C (e.g., room temperature) and stirred at that temperature for a desired time. In some examples, after adding nitrogen-containing hydrocarbons and / or dehydrating agents, the solution temperature is raised to 150°C.

[0074] The reaction solvent may include dimethyl sulfoxide (DMSO), diethyl sulfoxide, N,N-dimethylformamide (DMF), N,N-diethylformamide, N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 1-methyl-2-pyrrolidinone, N-cyclohexyl-2-pyrrolidone, 1,13-dimethyl-2-imidazolidinone, diethylene glycol dimethoxy ether, o-dichlorobenzene, phenol, cresol, xylenol, catechol, butyrolactone, hexamethylphosphoramide, and mixtures thereof. The reaction solvent and other reactants can be selected based on their suitability with the materials and methods applied; that is, based on whether the polymerized polyamic acid amide gel is cast onto a support film, injected into a moldable portion, or poured into a shape for further processing into a workpiece. In certain embodiments, the reaction solvent is DMSO.

[0075] With the above in mind, the incorporation of macropores into the aerogel polymer matrix, as well as the amount of such macropores present, can be carried out in the manner outlined. In one non-limiting manner, the formation of macropores, compared to small mesopores and micropores, can be controlled primarily by controlling the polymer / solvent dynamics during gel formation. In this way, the pore structure can be controlled, and the amount and volume of macroporous, mesoporous, and microporous cells can be controlled. For example, curing additives that reduce the solubility of the polymer produced during polymerization, such as 1,4-diazabicyclo[2.2.2]octane, may produce polymer gels containing more macropores compared to other curing additives that improve the solubility of the resulting polymer, such as trimethylamine. In another specific non-limiting example, when producing polyimide aerogels, the formation of macropores can be favored over small mesopores and micropores by increasing the ratio of rigid amines (e.g., p-phenylenediamine (p-PDA)) incorporated into the polymer backbone to more flexible diamines (e.g., -ODA).

[0076] The polymer solution may be cast onto a cast sheet covered with a support film for a certain period of time. Casting techniques may include spin casting, gravure coating, three-roll coating, roll knife coating, slot die extrusion, dip coating, Meyer rod coating, or other techniques. In one embodiment, the cast sheet is a polyethylene terephthalate (PET) cast sheet. After the time has elapsed, the polymerization-reinforced gel is removed from the cast sheet and prepared for a solvent exchange step. In some embodiments, the cast film can be heated stepwise to high temperatures to remove the solvent and convert the amic acid functional groups in the polyamic acid to polyimide by a dehydration cyclization reaction also known as imidization. In some examples, the polyamic acid may be converted to polyimide in solution by adding a chemical dehydrating agent, a catalyst, and / or heat.

[0077] In some embodiments, polyimide polymers can be produced by preparing polyamic acid polymers in a reaction vessel. The polyamic acid is then formed into a sheet or film and subsequently treated with a catalyst or heat and catalyst to convert the polyamic acid into polyimide.

[0078] The wet gel used to prepare the aerogel may be prepared by any known gel-forming technique, for example, by adjusting the pH and / or temperature of a diluted metal oxide solution to the point at which gelation occurs.

[0079] 2. Any solvent exchange After synthesizing the polymer gel, in certain cases, it may be desirable to perform a solvent exchange, replacing the reaction solvent with a more desirable second solvent. Therefore, in one embodiment, a solvent exchange can be performed by placing the polymer gel inside a pressure vessel and depositing it in a mixture containing the reaction solvent and the second solvent. A high-pressure atmosphere is then created inside the pressure vessel, thereby forcing the second solvent into the polymer gel and replacing part of the reaction solvent. Alternatively, the solvent exchange step may be carried out without using a high-pressure environment. Multiple solvent exchanges may be necessary. In some embodiments, solvent exchange is not essential.

[0080] The time required for solvent exchange will vary depending on the type of polymer being exchanged and the reaction solvent and second solvent used. In one embodiment, each solvent exchange may take 1 to 168 hours, or any period between those, including 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23, 24, 25, 50, 75, 100, 125, 150, 155, 160, 165, 166, 167, or 168 hours. In another embodiment, each solvent exchange may take approximately 1 to 60 minutes, or about 30 minutes. Exemplary second solvents include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 3-methyl-2-butanol, 3,3-dimethyl-2-butanol, 2-pentanol, 3-pentanol, 2,2-dimethylpropan-1-ol, cyclohexanol, diethylene glycol, cyclohexanone, acetone, acetylacetone, 1,4-dioxane, diethyl ether, dichloromethane, trichloroethylene, chloroform, carbon tetrachloride, water, and mixtures thereof. In certain non-limiting embodiments, the second solvent may have a freezing point suitable for carrying out supercritical or subcritical drying steps. For example, at 1 atmosphere, tert-butyl alcohol has a freezing point of 25.5°C and water has a freezing point of 0°C. Alternatively, drying may be carried out without using supercritical or subcritical drying steps, such as by evaporative drying techniques, as described below.

[0081] The temperature and pressure used in the solvent exchange process may be varied. The duration of the solvent exchange process can be adjusted by performing the solvent exchange at various temperatures, atmospheric pressures, or both, provided that the pressure and temperature in the pressure vessel do not cause either the first or second solvent to separate from the liquid phase into a gas, vapor, solid, or supercritical fluid. In general, higher pressure and / or temperature reduces the amount of time required for the solvent exchange, while lower temperature and / or pressure increases the amount of time required for the solvent exchange.

[0082] 3. Cooling and drying In one embodiment, the polymerized gel can be exposed to supercritical drying after solvent exchange. In this example, the solvent in the gel can be removed by supercritical CO2 extraction.

[0083] In another embodiment, after solvent exchange, the polymerized gel can be subjected to subcritical drying. In this example, the gel can be cooled to below the freezing point of the second solvent and subjected to a freeze-drying or lyophilization process to produce an aerogel. For example, if the second solvent is water, the polymerized gel is cooled to below 0°C. After cooling, the polymerized gel is subjected to reduced pressure for a certain period of time to sublimate the second solvent.

[0084] In yet another embodiment, after solvent exchange, the polymerized gel may be subjected to subcritical drying with optional heating after most of the second solvent has been removed by sublimation. In this example, the partially dried gel material is heated for a certain period of time to a temperature close to or above the boiling point of the second solvent. The period can range from several hours to several days, but a typical period is about 4 hours. During the sublimation process, some of the second solvent present in the polymerized gel is removed, leaving a gel that may have macropores, mesopores, or micropores, or any combination thereof, or all of such pore sizes. After the completion or near completion of the sublimation process, an aerogel is formed.

[0085] In yet another embodiment, after solvent exchange, the polymerized gel can be dried under ambient conditions by removing the solvent, for example, under a flow of gas (e.g., air, anhydrous gas, or an inert gas (e.g., nitrogen (N2) gas)). Furthermore, passive drying techniques can also be used, such as simply exposing the gel to ambient conditions without using an airflow.

[0086] Once cooled or dried, the film and stock shape can be configured for use in the laminate of the present invention. For example, the film or stock shape can be processed into any desired shape (e.g., by cutting or polishing) such as a square, rectangle, circle, triangle, irregular shape, or random shape. Alternatively, as described above, the film or stock shape can be attached to a support material with an adhesive or the like. In an alternative embodiment, the support material can be incorporated into a matrix of polymer aerogel, as described later.

[0087] 4. Incorporation of a reinforcing layer into the polymer aerogel matrix In addition to the methods described above regarding the use of adhesives for bonding polymer aerogels to support materials, any aspect of the present invention may include incorporating support materials into a polymer matrix to produce reinforced polymer aerogels without the use of adhesives. Notably, during the production of unreinforced polymer aerogels, a reinforcing support film can be used as a carrier to support the gelled film during processing. During unwinding, the gelled film can be irreversibly pressed into the carrier film. Pressing the gelled film into the carrier film can provide a substantial improvement in durability. In another example, during the solution casting step described above, the polymer solution can be cast into the reinforcing or support material.

[0088] Substrate selection and direct casting may enable optimization (e.g., minimization) of the thickness of the resulting reinforced aerogel material. This process can also be extended to the production of fiber-reinforced polymer aerogels, providing internally reinforced polyimide aerogels as an example. The process may include (a) forming a polyamic acid solution from a mixture of dianhydride and diamine monomers in a polar solvent such as DMSO, DMAc, NMP, or DMF; (b) contacting the polyamic acid solution with the chemical curing agents and chemical dehydrating agents mentioned above to initiate chemical imidation; (c) casting the polyamic acid solution onto a fiber support before gelation and allowing it to permeate; (d) gelling the catalytic polyamic acid solution around and within the fiber support during chemical imidation; (e) optionally performing solvent exchange to facilitate drying; and (f) removing the transient liquid phase contained within the gel by supercritical, subcritical, or ambient drying to obtain an internally reinforced aerogel. [Examples]

[0089] The present invention will be described in detail with specific examples. The following examples are provided for illustrative purposes only and are not intended to limit the invention in any way. Those skilled in the art will readily recognize non-material parameters that can be changed or modified to obtain essentially the same results.

[0090] Table 1 shows the acronyms of the compounds used in the following examples.

[0091] [Table 1]

[0092] The structure of the starting material is shown below. TIFF2026076254000003.tif41158

[0093] Example 1 (Preparation of highly branched BPDA / DMB-ODA polyimide) A reaction vessel equipped with a stirrer and a water jacket was used. The temperature was maintained in the range of 18–35°C by adjusting the water flow rate through the reaction vessel jacket. DMSO (108.2 lbs. 49.1 kg) was added to the reaction vessel, and the stirrer speed was adjusted to 120–135 rpm. TAPOB (65.13 g) was added to the solvent. To this solution, DMB (1081.6 g) was added, followed by ODA (1020.2 g). Next, the first part of BPDA (1438.4 g) was added. After stirring for 20 minutes, the viscosity of the reaction mixture sample was analyzed using a Brookfield DV1 viscometer (Brookfield, AMETEK, USA). The second part of BPDA (1407.8 g) was added, and the reaction mixture was stirred for a further 20 minutes. The third part of BPDA (138.62 g) was added, and the reaction mixture was stirred for 20 minutes. The viscosity of the reaction mixture sample was analyzed. After stirring for 8 hours, PA (86.03 g) was added. The resulting reaction mixture was stirred until no more solids were visible. After 2 hours, the product was removed from the reaction vessel, filtered, and weighed.

[0094] Example 2 (Preparation of highly branched polyimide aerogel monoliths by freeze-drying) The resin prepared in Example 1 (approximately 10,000 g) was mixed with triethylamine (approximately 219 g) and acetic anhydride (approximately 561 g) for 5 minutes. After mixing, the resulting solution was poured into a square 15" x 15" mold and left for 48 hours. The gelled product was removed from the mold and placed in an acetone bath. After immersion for 24 hours, the acetone bath was replaced with fresh acetone. The immersion and replacement process was repeated 5 times. After the final replacement, the bath was replaced with tertiary butyl alcohol. After immersion for 24 hours, the tertiary butyl alcohol bath was replaced with fresh tertiary butyl alcohol. The immersion and replacement process was repeated 3 times. Subsequently, the portion was flash-frozen and subjected to subcritical drying at 5°C for 96 hours, followed by drying under reduced pressure at 50°C for 48 hours. The final recovered aerogel portion was observed using scanning electron microscopy (SEM) with a Phenom Pro Scanning Electron Microscope (Phenom-World, the Netherlands) and showed an open-cell structure. It was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA) and measured at 0.22 g / cm³. 3 The density and porosity of 88.5% were determined by ASTM D395-16, the compressive modulus was 2.2 MPa, and the compressive strength at 25% strain was 3.5 MPa, also determined by ASTM D395-16. The pore diameter distribution was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA), and the pore diameter distribution is shown in Figure 7. From the data, it was determined that 100% of the pores were macropores, and the average pore diameter was approximately 1,200 nm, thus confirming the formation of a macroporous aerogel structure.

[0095] Example 3 (Preparation of highly branched polyimide aerogel monoliths by heat drying) The resin prepared in Example 1 (approximately 10,000 g) was mixed with triethylamine (approximately 219 g) and acetic anhydride (approximately 561 g) at a temperature of 10-35°C for 5 minutes. After mixing, the resulting solution was poured into a square 15" x 15" mold and left for 48 hours. The gelled product was removed from the mold and placed in an acetone bath. After immersion for 24 hours, the acetone bath was replaced with fresh acetone. The immersion and replacement process was repeated five times. After the final replacement, the portion was dried in an ambient air drying process (approximately 20-30°C) over 48 hours to evaporate most of the acetone, followed by heat drying at 50°C for 4 hours, 100°C for 2 hours, 150°C for 1 hour, and then 200°C for 30 minutes. The final recovered aerogel had similar properties to those observed in Example 2.

[0096] Example 4 (Preparation of highly branched polyimides) As described in Example 1, approximately 2.86 g of TAPOB was added to a reaction vessel containing approximately 2,523.54 g of DMSO at a temperature of 18-35°C. To this solution, the first part of DMB (approximately 46.75 g) was added, followed by the first part of ODA (approximately 44.09 g). After stirring for approximately 20 minutes, the first part of BPDA (approximately 119.46 g) was added. After stirring for approximately 20 minutes, TAPOB (approximately 2.86 g), DMB (approximately 46.75 g), and ODA (approximately 44.09 g) were added. After stirring for approximately 20 minutes, BPDA (approximately 119.46 g) was added. After stirring for approximately 20 minutes, TAPOB (approximately 2.86 g), DMB (approximately 46.75 g), and ODA (approximately 44.09 g) were added. After stirring for approximately 20 minutes, BPDA (approximately 119.46 g) was added. After stirring for approximately 8 hours, PA (approximately 50.12 g) was added. The resulting reaction mixture was stirred until no more solids were visible. After approximately 2 hours, the product was removed from the reaction vessel, filtered, and weighed.

[0097] Example 5 (Preparation of highly branched polyimide aerogel monoliths by freeze-drying) The resin prepared in Example 4 (approximately 400 g) was mixed with 2-methylimidazole (approximately 53.34 g) at a temperature of 18-35°C for 5 minutes, and then mixed with benzoic anhydride (approximately 161.67 g) for 5 minutes. After mixing, the resulting solution was poured into a square 3" x 3" mold and placed in a 75°C oven for 30 minutes, then left at room temperature overnight. The gelled product was removed from the mold and placed in an acetone bath. After immersion for 24 hours, the acetone bath was replaced with fresh acetone. The immersion and replacement process was repeated 5 times. After the last replacement, the bath was replaced with tertiary butyl alcohol. After immersion for 24 hours, the tertiary butyl alcohol bath was replaced with fresh tertiary butyl alcohol. The immersion and replacement process was repeated 3 times. Subsequently, the portion was frozen in a shelf freezer and subjected to subcritical drying at 5°C for 96 hours, followed by drying under reduced pressure at 50°C for 48 hours. The final recovered aerogel portion was observed using scanning electron microscopy (SEM) with a Phenom Pro Scanning Electron Microscope (Phenom-World, the Netherlands) and was found to have an open-cell structure. It was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA) and measured at 0.15 g / cm³. 3 The density and porosity of 92.2% were observed. The pore size distribution was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA), and the pore size distribution is shown in Figure 8. From the data, it was determined that 96.3% of the pore volume of the molded aerogel was occupied by pores with an average pore diameter greater than 50 nm, and therefore a macroporous aerogel structure was formed.

[0098] Example 6 (Preparation of highly branched polyimides) As described in Example 1, approximately 2,776.57 g of DMSO was added to a reaction vessel, to which approximately 2.05 g of TAPOB was added at a temperature of 18-35°C. To this solution, approximately 33.54 g of DMB was added, followed by approximately 31.63 g of ODA. After stirring for approximately 20 minutes, approximately 67.04 g of PMDA was added. After stirring for approximately 20 minutes, approximately 2.05 g of TAPOB, approximately 33.54 g of DMB, and approximately 31.63 g of ODA were added. After stirring for approximately 20 minutes, approximately 67.04 g of PMDA was added. After stirring for approximately 20 minutes, approximately 2.05 g of TAPOB, approximately 33.54 g of DMB, and approximately 31.63 g of ODA were added. After stirring for approximately 20 minutes, approximately 67.04 g of PMDA was added. After stirring for approximately 8 hours, PA (approximately 18.12 g) was added. The resulting reaction mixture was stirred until no more solids were visible. After approximately 2 hours, the product was removed from the reaction vessel, filtered, and weighed.

[0099] Example 7 (Preparation of highly branched polyimide aerogel monoliths by freeze-drying) The resin prepared in Example 6 (approximately 400 g) was mixed with 2-methylimidazole (approximately 40.38 g) at a temperature of 18-35°C for 5 minutes, and then mixed with benzoic anhydride (approximately 122.38 g) for 5 minutes. After mixing, the resulting solution was poured into a square 3" x 3" mold and placed in a 75°C oven for 30 minutes, then left at room temperature overnight. The gelled product was removed from the mold and placed in an acetone bath. After immersion for 24 hours, the acetone bath was replaced with fresh acetone. The immersion and replacement process was repeated 5 times. After the last replacement, the bath was replaced with tertiary butyl alcohol. After immersion for 24 hours, the tertiary butyl alcohol bath was replaced with fresh tertiary butyl alcohol. The immersion and replacement process was repeated 3 times. Subsequently, the portion was frozen in a shelf freezer and subjected to subcritical drying at 5°C for 96 hours, followed by drying under reduced pressure at 50°C for 48 hours. The final recovered aerogel portion was observed using scanning electron microscopy (SEM) with a Phenom Pro Scanning Electron Microscope (Phenom-World, the Netherlands) and showed an open-cell structure. It was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA) and measured at 0.23 g / cm³. 3 The aerogel exhibited a density and porosity of 82.7%. The pore size distribution was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA), and the pore size distribution is shown in Figure 9. From the data, it was determined that pores with an average pore diameter greater than 50 nm occupied 90.6% of the aerogel's pore volume.

[0100] Example 8 (Preparation of highly branched polyamic film) A reaction vessel equipped with a stirrer and a water jacket was used. The temperature was maintained in the range of 20-28°C by adjusting the water flow rate through the reaction vessel jacket. DMSO (108.2 lbs. 49.1 kg) was added to the reaction vessel, and the stirrer speed was adjusted to 120-135 rpm. TAPOB (65.03 g) was added to the solvent. To this solution, DMB (1,080.96 g) and then ODA (1,018.73 g) were added. The first part of BPDA (1,524.71 g) was added. After stirring for 20 minutes, the viscosity of the sample of the reaction mixture was analyzed. The second part of BPDA (1,420.97 g) was added, and the reaction mixture was stirred for a further 20 minutes. The viscosity of the sample of the reaction mixture was analyzed. The third part of BPDA (42.81 g) was added, and the reaction mixture was stirred for a further 20 minutes. The viscosity of the sample of the reaction mixture was analyzed. After stirring for 8 hours, PA (77.62 g) was added. The resulting reaction mixture was stirred until no more solids were visible. After 2 hours, the resin was removed from the reaction vessel, filtered, and weighed.

[0101] 10,000 g of resin was mixed with 250 g of 2-methylimidazole for 5 minutes. 945 g of benzoic anhydride was added, and the solution was mixed for another 5 minutes. After mixing, the resulting solution was poured onto a mobile polyester substrate and heated in a 100°C oven for 30 seconds. The gelled film was collected and placed in an acetone bath. After immersion for 24 hours, the acetone bath was replaced with fresh acetone. The immersion and replacement process was repeated six times. After the final replacement, the gelled film was removed. The acetone solvent was evaporated at room temperature under a flow of air, followed by drying at 200°C for 2 hours. The final recovered aerogel portion was observed using scanning electron microscopy (SEM) with a Phenom Pro Scanning Electron Microscope (Phenom-World, the Netherlands) and showed an open-cell structure. It was measured according to ASTM D4404-10 using a Micromeritics® AutoPore V 9605 Automatic Mercury Penetrometer (Micromeritics® Instrument Corporation, USA) and measured at 0.20 g / cm³. 3The film exhibited a density and porosity of >80%. The final recovered film, measured according to ASTM D882-12, showed a tensile strength of 1200 psi (8.27 MPa) and elongation of 14% at room temperature. The film had an average pore diameter of 400 nm.

[0102] Example 9 (Preparation of copper-clad polyimide aerogel laminates) A laminate was prepared in which a polyimide aerogel layer was bonded between two copper layers by thermal lamination of an adhesive sheet to the aerogel film on either side of the aerogel film. Each copper foil layer had a thickness of 1.4 mils, and the polyimide aerogel layer was a 139.7 micron (5.5 mil) Blueshift AeroZero® film.

[0103] Prior to lamination, the AeroZero® film was dried in a convection oven at 120°C for 30 minutes. After assembling the aerogel film between two adhesive sheets with a copper foil layer on top, the sample was placed in a vacuum press. Copper-clad laminates were fabricated using three low Dk / Df adhesives: Teflon FEP (Dupont), Pyralux GPL (Dupont), and TSU 510 (ToyoChem).

[0104] The press was heated to 180°C using a temperature gradient of 5°C / min and a pressure increase from 4 psi to 300 psi. The press was then kept isothermal at 180°C for a range of 10 to 60 minutes, depending on the type of adhesive used. The press was then cooled to 50°C, maintaining a temperature of 5°C / min and a pressure of 300 psi.

[0105] Example 10 (Dielectric properties of polyimide aerogel film) The dielectric constant (Dk) and loss tangent (Df) characteristics of Blueshift AeroZero® film at 1 MHz and 1 GHz were measured according to the IPC TM-650 Method 2.5.5.9. Parallel Plate Method. Samples were pre-conditioned at 23±5°C and 50±5%RH for a minimum of 24 hours prior to testing. The thickness of the polyimide aerogel film used was 148 microns. The dielectric properties are shown in Table 1.

[0106] [Table 1]

[0107] Example 11 (Dielectric properties of polyimide aerogel films at high frequencies) The dielectric constant (Dk) and loss tangent (Df) of a 157.8 micron thick polyimide aerogel film were measured at 10 GHz using a Damaskos Thin Sheet tester. The results were Dk = 1.45 and Df = 0.0046.

[0108] Example 12 (Dielectric properties of polyimide aerogel stock shape) The dielectric constant (Dk) and loss tangent (Df) of a 10.2 mm thick polyimide aerogel sample were measured at room temperature (22°C, 22% RH) using a DI Model 08 Thin Sheet Tester and a DI Model 900T Open Resonator, with an Anritsu VectorStar vector network analyzer controlled by CAVITY® for Macintosh OS X. Thin Sheet Tester measurements conform to ASTM D 2520 Part C. Table 2 shows the average dielectric constant (Dk) and loss tangent (Df) measured in four directions (X1, X2, Y1, and Y2) using the Model 08 Thin Sheet Tester.

[0109] [Table 2]

[0110] Table 3 shows the average dielectric constant (Dk) and loss tangent (Df) measured in two directions (X, Y) using a Model 900T Open Resonator for frequencies in the range of 7.3 GHz to 50 GHz.

[0111] [Table 3]

[0112] Example 13 (Dielectric properties of polyimide aerogel copper-clad laminates) The dielectric constant (Dk) and loss tangent (Df) of an etched sample of a 161-micron thick polyimide aerogel copper-clad laminate were measured at 10 GHz. The results were Dk = 2.0 and Df = 0.004.

[0113] The aforementioned specification and examples provide a complete description of the structure and use of exemplary embodiments. While certain embodiments have been described in some detail, or with respect to one or more individual embodiments, those skilled in the art will be able to make many modifications to the disclosed embodiments without departing from the scope of the invention. Therefore, there is no intention to limit the various exemplary embodiments of the apparatus and methods to any particular form disclosed. Rather, they include all modifications and substitutions within the scope of the claims, and embodiments other than those shown may include some or all of the features of the embodiments shown. For example, elements may be omitted or combined as a single structure and / or connections may be substituted. Furthermore, where appropriate, aspects of any embodiment described above may be combined with aspects of any other embodiment described above to form further embodiments having equivalent or different characteristics and / or functions and addressing the same or different problems. Similarly, it will be understood that the advantages and merits described above may relate to one embodiment or to several embodiments.

[0114] Unless such a limitation is explicitly referenced in the given claims using the terms “means” or “step,” the claims are not intended to include, and should not be construed to include, a means-plus or step-plus-function limitation.

Claims

1. One or more conductive layers, each containing at least 90% by weight of copper, One or more electrically insulating layers bonded to a conductive layer, each comprising a polymer aerogel layer, and A laminate containing, At least one of the opposing front and rear surfaces of the laminate is defined by one of the conductive layers. Laminated structure.

2. The conductive layer comprises two or more conductive layers. At least a portion of the front surface of the laminate is defined by one of the first conductive layers, and At least a portion of the rear surface of the laminate is defined by one of the second conductive layers. The laminate according to claim 1.

3. The laminate according to claim 1 or 2, wherein at least one of the conductive layers has a thickness of 0.5 mil to 3.0 mil or 0.5 mil to 0.9 mil.

4. The laminate according to claim 3, wherein at least one of the conductive layers has a thickness of about 0.7 mils.

5. At least one of the conductive layers has a conductivity of 0.35 to 3.0 ounces per square foot (oz / ft 2 ) or 0.35–0.75 oz / ft 2 A laminate according to any one of claims 1 to 4, having a surface density.

6. At least one of the conductive layers is approximately 0.5 oz / ft 2 The laminate according to claim 5, having a surface density.

7. The laminate according to any one of claims 1 to 6, wherein at least one of the electrical insulating layers includes an open-cell structure of polymer aerogel layer.

8. The laminate according to any one of claims 1 to 7, wherein at least one of the electrical insulating layers comprises a polymer aerogel layer with micropores, mesopores, and / or macropores.

9. For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Micropores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. The laminate according to claim 8.

10. For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Mesopores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. The laminate according to claim 8.

11. For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Macropores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. The laminate according to claim 8.

12. For at least one of the electrical insulation layers, The polymer aerogel layer has pore volume, Micropores and / or mesopores occupy at least 10%, at least 50%, at least 75%, or at least 95% of the pore volume. The laminate according to claim 8.

13. The laminate according to any one of claims 1 to 7, wherein at least one of the electrical insulating layers is a polymer aerogel layer having an average pore diameter of 2.0 nm to 50 nm.

14. The laminate according to any one of claims 1 to 7, wherein at least one of the electrical insulating layers is a polymer aerogel layer having an average pore diameter of 50 nm to 5,000 nm.

15. The laminate according to claim 14, wherein the average pore diameter is 100 nm to 800 nm, 100 nm to 500 nm, 150 nm to 400 nm, 200 nm to 300 nm, or 225 nm to 275 nm.

16. The laminate according to any one of claims 1 to 15, wherein at least one of the electrical insulating layers is a polymer aerogel layer containing at least 90% by weight of an organic polymer.

17. The laminate according to any one of claims 1 to 15, wherein at least one of the electrical insulating layers comprises a polymer aerogel layer containing at least 90% by weight of polyimide, polyamide, polyaramid, polyurethane, polyurea, and / or polyester.

18. The laminate according to claim 17, wherein at least one of the electrical insulating layers comprises a polymer aerogel layer containing at least 90% by weight of polyimide.

19. The laminate according to any one of claims 1 to 18, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 20 mils or less.

20. The laminate according to claim 19, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 12 mils or less.

21. The laminate according to claim 20, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 7.0 mil or less.

22. The laminate according to any one of claims 1 to 18, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a thickness of 3.0 to 20 mils, 3.0 to 15 mils, 3.0 to 12 mils, or 3.0 to 7.0 mils.

23. The laminate according to any one of claims 1 to 22, wherein at least one of the electrical insulating layers has a polymer aerogel layer with a decomposition temperature of 400°C or higher, 450°C or higher, or 500°C or higher.

24. One or more adhesive layers are placed between adjacent layers of the conductive layer and the electrically insulating layer, respectively. A laminate according to any one of claims 1 to 23, including the laminate described in any one of claims 1 to 23.

25. The laminate according to claim 24, wherein at least one of the adhesive layers comprises a fluoropolymer film.

26. The laminate according to claim 24, wherein at least one of the adhesive layers comprises a polyimide film.

27. The laminate according to claim 24, wherein at least one of the adhesive layers comprises B-stage epoxy.

28. The laminate according to any one of claims 24 to 27, wherein at least one of the adhesive layers has a dielectric constant of 3.5 or less, 3.0 or less, 2.5 or less, or 2.25 or less at 10 GHz.

29. The laminate according to any one of claims 24 to 28, wherein at least one of the adhesive layers has a dielectric loss tangent of 0.0040 or less, 0.0035 or less, 0.0030 or less, 0.0025 or less, 0.0020 or less, or 0.0015 or less at 10 GHz.

30. The laminate according to any one of claims 24 to 29, wherein at least one of the adhesive layers has a decomposition temperature of 350°C or higher, 375°C or higher, 400°C or higher, 450°C or higher, or 500°C or higher.

31. The laminate according to any one of claims 24 to 30, wherein at least one of the adhesive layers has a glass transition temperature or melting point of 100°C or higher, 150°C or higher, 200°C or higher, 225°C or higher, 250°C or higher, or 275°C or higher.

32. The laminate according to any one of claims 24 to 31, wherein at least one of the adhesive layers has a thickness of 0.3 to 5 mils, 0.3 to 3.0 mils, 0.3 to 2.0 mils, 0.3 to 1.2 mils, or 0.75 to 1.25 mils.

33. The electrical insulating layer includes two or more electrical insulating layers, In the electrical insulating layer, there is no conductive layer placed between adjacent layers. A laminate according to any one of claims 1 to 32.

34. A laminate according to any one of claims 1 to 33, having a thickness of 5.0 mil to 100 mil, 5.0 mil to 75 mil, 5.0 mil to 50 mil, or 5.0 mil to 30 mil.

35. The laminate according to any one of claims 1 to 34, wherein a part of the front surface of the laminate is arranged in a roll shape so as to face a part of the rear surface of the laminate.

36. A laminate according to any one of claims 1 to 35, having a dielectric constant of 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less, or 1.6 or less at 10 GHz.

37. The laminate according to claim 36, wherein the dielectric constant is 1.75 or less.

38. A laminate according to any one of claims 1 to 37, having a dielectric loss tangent of 0.0025 or less, 0.00225 or less, 0.002 or less, 0.00175 or less, or 0.0015 or less at 10 GHz.

39. The laminate according to claim 38, wherein the dielectric loss tangent is 0.002 or less.

40. Includes a 1-territorial reinforcing layer, Each of the reinforcing layers has a bending stiffness at least 10% greater than the bending stiffness of the conductive layer and the electrical insulating layer, and / or For at least one of the electrical insulating layers, at least one reinforcing layer is at least partially embedded in the polymer aerogel layer such that the Young's modulus of the electrical insulating layer is at least 200 MPa, and / or In at least one of the electrical insulating layers, multiple fibers are dispersed in the polymer aerogel layer such that the Young's modulus of the electrical insulating layer is at least 200 MPa. A laminate according to any one of claims 1 to 39.

41. At least one of the reinforcement layers, One or more unidirectional sheets, woven sheets, or nonwoven sheets containing fibers, and / or one or more paper sheets. The laminate according to claim 40, including the following:

42. A laminate according to any one of claims 1 to 40, which does not contain fibers.

43. A laminate according to any one of claims 1 to 41, A solder mask layer bonded to the surface of at least one of the front and rear surfaces, such that the solder mask layer covers at least a large portion of the surface, and comprising at least 90% by weight of a polymer. A circuit board, including a circuit board.

44. The circuit board according to claim 43, wherein the thickness of the solder mask layer is 3.2 mils or less, 1.6 mils or less, or 0.8 mils or less.

45. Apparatus comprising a circuit board according to claim 43 or 44, The circuit board includes an antenna electrically coupled to it, and / or A device that is an electrical amplifier, radar system, or communication system.

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