Liquid crystal polymer composite, liquid crystal polymer composite film, and metal-clad laminate containing the same

Abstract

A liquid crystal polymer composite film is formed from a resin composite comprising one or more liquid crystal polymers and one or more fillers. The liquid crystal polymer composite film has a thickness in the range of 10 μm to 200 μm and a ratio of in-plane permittivity in the longitudinal direction to the transverse direction in the frequency range of 1.0 to 1.4 in the frequency range of 1 GHz to 10 GHz. A metal-clad laminate comprises a liquid crystal polymer composite film and a metal-clad layer laminated to the main surface of the liquid crystal polymer composite film. The metal-clad laminate may be included as part of an antenna.

Description

Technology Field

[0001] This is a PCT international patent application claiming the benefit of U.S. Provisional Application No. 63 / 128,564 filed December 21, 2020 and U.S. Provisional Application No. 63 / 165,480 filed March 24, 2021, the entire contents of both of which are incorporated herein by reference.

[0002] The present invention relates to liquid crystal polymer composites, and in particular, to liquid crystal polymer composite films that may be included in a metal-clad laminate. The metal-clad laminate may be used as a multilayer stack-up of rigid multilayer circuits, a multilayer stack of flexible PCBs, or a single layer of a “hybrid” structure in communication products such as antenna assemblies, or in multilayer applications such as multilayer circuit boards. Background Technology

[0003] The high-frequency market continues to expand. For example, 5G communication standards provide networks capable of using frequencies up to 40 GHz, while millimeter-wave (mmWave) radar for autonomous driving operates at a higher 70 GHz. Devices such as mobile handsets, tablets, laptops, vehicles, and other devices include antenna substrate assemblies to utilize 5G networks. These antenna assemblies may include electrically conductive, flexible, or rigid substrates to which antenna materials are applied (e.g., copper-clad laminates). However, there may be challenges in providing antenna substrates with electrical and physical / mechanical properties suitable for use in high-frequency applications. The problem to be solved

[0004] The present disclosure relates to a liquid crystal polymer (“LCP”) composite that can be processed into a film. This LCP composite film can be used as part of a metal-clad laminate and may be suitable for use in high-frequency products such as antenna assemblies or automotive radar. The LCP composite film produced from the LCP composite may have low in-plane dielectric permittivity and low loss tangent for high-frequency applications. The film produced from the LCP composite may also have low anisotropy for one or more of these properties in some embodiments. means of solving the problem

[0005] The present invention relates to different limitations, options, and embodiments that may be included alone or in combination.

[0006] A liquid crystal polymer composite film formed from a resin composite, wherein the resin composite comprises one or more liquid crystal polymers present in an amount ranging from 40% to 95% by weight based on the total weight of the liquid crystal polymer composite; and one or more fillers present in an amount ranging from 5% to 60% by weight based on the total weight of the liquid crystal polymer composite, the thickness of the liquid crystal polymer composite film is in the range of 10 μm to 200 μm, and the ratio of the in-plane permittivity in the machine direction of the liquid crystal polymer composite film to the in-plane permittivity in the transverse direction of the liquid crystal polymer composite film is in the range of 1.0 to 1.4 in the frequency range of 1 GHz to 10 GHz.

[0007] In the liquid crystal polymer composite film, the ratio of the loss tangent in the longitudinal direction of the liquid crystal polymer composite film to the loss tangent in the transverse direction of the liquid crystal polymer composite film is in the range of 0.2 to 1.0 in the frequency range of 1 GHz to 10 GHz.

[0008] In the liquid crystal polymer composite film, the one or more liquid crystal polymers comprise a polymer comprising monomer units derived from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.

[0009] In the liquid crystal polymer composite film above, the one or more liquid crystal polymers include a polymer comprising monomer units derived from 4-hydroxybenzoic acid.

[0010] In the liquid crystal polymer composite film above, the one or more fillers include one or more of zeolite, fused silica, or talc.

[0011] In the liquid crystal polymer composite film above, the melt viscosity of the resin composite at a melting temperature of 320 °C and a shear rate of 1800 (1 / sec) is 30 Pa-s or more and less than 120 Pa-s.

[0012] In the liquid crystal polymer composite film, the melt viscosity of the resin composite at a melting temperature of 320 °C and a shear rate of 1800 (1 / sec) is 36 Pa-s or more and less than 80 Pa-s, and the thickness of the liquid crystal polymer composite film is in the range of 10 μm to 100 μm.

[0013] In the liquid crystal polymer composite film, the melt viscosity of the resin composite at a melting temperature of 320 °C and a shear rate of 1800 (1 / sec) is 36 Pa-s or more and less than 57 Pa-s, and the thickness of the liquid crystal polymer composite film is in the range of 10 μm to 100 μm.

[0014] The thickness of the liquid crystal polymer composite film is in the range of 25 μm to 200 μm.

[0015] The metal-clad laminate comprises the liquid crystal polymer composite film; and a metal layer laminated to the major surface of the liquid crystal polymer composite film, wherein the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the permittivity in the transverse direction of the liquid crystal polymer composite film is in the range of 0.9 to 1.2 in the frequency range of 1 GHz to 10 GHz.

[0016] In the above metal-clad laminate, the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the permittivity in the transverse direction of the liquid crystal polymer composite film is in the range of 0.9 to 1.1 in the frequency range of 1 GHz to 10 GHz.

[0017] In the above metal-clad laminate, the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the permittivity in the transverse direction of the liquid crystal polymer composite film provided to the metal-clad laminate is smaller than the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the permittivity in the transverse direction of the liquid crystal polymer composite film prior to lamination.

[0018] In the above metal-clad laminate, the metal is copper, and the roughness of the copper surface is less than 5 microns when measured as Rz 10-point mean roughness.

[0019] In the metal-clad laminate above, the peel strength of the copper in the liquid crystal polymer composite film is in the range of 6.0 to 13.0 lb / in.

[0020] In the above metal-clad laminate, the metal is copper, and the roughness of the copper surface is 3 microns or less when measured by an unknown 10-point average roughness.

[0021] In the above metal-clad laminate, the peel strength of MHT copper in the liquid crystal polymer composite film is in the range of 4.0 to 10.0 lb / in.

[0022] The metal-clad laminate further comprises an additional metal-clad layer laminated to an additional main surface of the liquid crystal polymer composite film.

[0023] In the above metal-clad laminate, the ratio of the coefficient of thermal expansion of the liquid crystal polymer composite film in the longitudinal direction (MD / TD) to the transverse direction is in the range of 0.9 to 1.0.

[0024] In the above metal-clad laminate, the thickness of the laminate is in the range of 15 μm to 50 μm, and the laminate is flexible.

[0025] In the above metal-clad laminate, the thickness of the laminate is in the range of 50 μm to 200 μm, and the laminate is rigid.

[0026] A metal-clad laminate comprises a liquid crystal polymer composite film; and a metal layer laminated to the main surface of the liquid crystal polymer composite film, wherein the composite film has a dielectric constant of less than 3.1.

[0027] The antenna includes the metal-clad laminate.

[0028] The substrate includes the metal-clad laminate.

[0029] The metal-clad laminate further comprises a third layer, said layer comprises a material selected from the group comprising FR4, PTFE, polyimide, and combinations thereof.

[0030] The aforementioned and other features of the present invention are described in more detail below with reference to the attached drawings. Brief explanation of the drawing

[0031] FIG. 1 is a schematic perspective view of an exemplary LCP composite film. Figure 2 is a schematic side view of an exemplary metal-clad laminate. Figure 3 is a schematic side view of an exemplary metal-clad laminate. Figures 4 and 5 are graphs showing X-ray diffraction (XRD) data of LCP composite films and metal-clad laminates. FIG. 6 illustrates a general arrangement of a film extruder having an associated extrusion die according to one embodiment of the present invention. Specific details for implementing the invention

[0032] The liquid crystal polymer composite (“LCP composite”) of the present disclosure comprises a mixture of one or more liquid crystal polymer materials and one or more fillers.

[0033] A liquid crystal polymer (“LCP”) is a polymer that is anisotropic in itself when tested using a thermo-optical test (TOT) or any reasonable variation thereof, as described in U.S. Patent No. 4,118,372, incorporated herein by reference.

[0034] LCP materials are anisotropic materials, and their mechanical and electrical properties may differ in directions parallel to or transverse to the flow direction (longitudinal direction).

[0035] There are three types of liquid crystal polymers developed for industrial use. All are based on the utilization of hydroxybenzoic acid. Type I was first used by Sumitomo and Solvay, possesses the highest heat distortion temperature, and is primarily used for connectors. Types II and III are "copolymers" developed to lower temperature resistance and optimize the processing of LCPs.

[0036] The present invention relates to composite systems comprising fillers applicable to all three types of LCPs to adjust properties that make them “composites” having unique properties for high-frequency circuit applications. Accordingly, the present invention relates to both homopolymers and copolymers of HBA (hydroxybenzoic acid).

[0037]

[0038] LCPs are typically derived from monomers comprising aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, aromatic diols, aliphatic diols, aromatic hydroxyamines, and / or aromatic diamines. For example, aromatic polyesters obtained by polymerizing one or more aromatic hydroxycarboxylic acids; aromatic polyesters obtained by polymerizing an aromatic dicarboxylic acid, one or more aliphatic dicarboxylic acids, an aromatic dial, and one or more aliphatic dials, or an aromatic hydroxycarboxylic acid; Aromatic polyesters obtained by polymerizing one or more monomers selected from the group consisting of aromatic dicarboxylic acids, aliphatic dicarboxylic acids, aromatic diols, and aliphatic diols; aromatic polyester amides obtained by polymerizing aromatic hydroxyamines, one or more aromatic diamines, and one or more aromatic hydroxycarboxylic acids; aromatic polyester amides obtained by polymerizing aromatic hydroxyamines, one or more aromatic diamines, one or two aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, and one or more aliphatic carboxylic acids; It may be an aromatic polyesteramide obtained by polymerizing an aromatic hydroxyamine, one or more aromatic diamines, one or more aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, one or more aliphatic carboxylic acids, aromatic diols, and one or more aliphatic diols.

[0039] Examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and halogen-, alkyl-, or allyl-substituted derivatives of hydroxybenzoic acid.

[0040] Examples of aromatic dicarboxylic acids include terephthalic acid; isophthalic acid; 3,3′-diphenyl dicarboxylic acid; 4,4′-diphenyl dicarboxylic acid; 1,4-naphthalene dicarboxylic acid; 1,5-naphthalene dicarboxylic acid; 2,6-naphthalene dicarboxylic acid; and alkyl- or halogen-substituted aromatic dicarboxylic acids such as t-butylterephthalic acid, chloroterephthalic acid, etc.

[0041] Examples of aliphatic dicarboxylic acids include cyclic aliphatic dicarboxylic acids such as trans-1,4-cyclohexane dicarboxylic acid; cis-1,4-cyclohexane dicarboxylic acid; 1,3-cyclohexane dicarboxylic acid; and their substituted derivatives.

[0042] Examples of aromatic diols are hydroquinone; biphenol; 4,4′-dihydroxydiphenyl ether; 3,4′-dihydroxydiphenyl ether; bisphenol A; 3,4′-dihydroxydiphenylmethane; 3,3′-dihydroxydiphenylmethane; 4,4′-dihydroxydiphenylsulfone; 3,4′-dihydroxydiphenylsulfone; 4,4′-dihydroxydiphenylsulfide; 3,4′-dihydroxydiphenylsulfide; 2,6′-naphthalenediol; 1,6′-naphthalenediol; It includes 4,4′-dihydroxybenzophenone; 3,4′-dihydroxybenzophenone; 3,3′-dihydroxybenzophenone; 4,4′-dihydroxydiphenyldimethylsilane; and their alkyl- and halogen-substituted derivatives.

[0043] Examples of aliphatic diols include cyclic, linear, and branched aliphatic diols such as trans-1,4-hexanediol; cis-1,4-hexanediol; trans-1,3-hexanediol; cis-1,2-cyclohexanediol; ethylene glycol; 1,4-butanediol; 1,6-hexanediol; 1,8-octanediol; trans-1,4-cyclohexanedimethanol; cis-1,4-cyclohexanedimethanol, etc.; and their substituted derivatives.

[0044] Examples of aromatic hydroxyamines and aromatic diamines include 4-aminophenol, 3-aminophenol, p-phenylenediamine, m-phenylenediamine, and their substituted derivatives.

[0045] One or more LCPs may be produced using any method known in the art. For example, they may be produced by standard polycondensation techniques (melt polymerization, solution polymerization, and solid-phase polymerization). In some embodiments, it is preferable that the LCPs be produced in an inert gas atmosphere under anhydrous conditions. For example, in a melt acidolysis method, the required amounts of acetic anhydride, 4-hydroxybenzoic acid, diol, and terephthalic acid are stirred and then heated in a reaction vessel provided with a combination of a nitrogen introduction tube and a distillation head or cooler; after by-products such as acetic acid are removed through the distillation head or cooler, they are collected. After the amount of captured by-products becomes constant and the polymerization is almost complete, the molten mass is heated under vacuum (usually 10 mmHg or less), and the remaining by-products are removed to complete the polymerization.

[0046] In some embodiments, one or more LCPs have number average molecular weights in the range of about 2,000 to about 200,000. In other embodiments, LCPs have number average molecular weights in the range of about 10,000 to about 20,000. Molecular weight can affect the melt viscosity of the LCP.

[0047] One or more LCPs included in the LCP composite are preferably thermoplastic polyester polymers containing rigid mesogenic linkages. In some embodiments, one or more LCP polymers have crystalline melting points in the range of about 250 °C to 375 °C. In other embodiments, one or more LCP polymers have crystalline melting points in the range of about 270 °C to 355 °C.

[0048] One or more LCPs can be classified as pure polymers in that they are not reinforced, filled / mixed, or otherwise modified by additional materials before being combined with one or more fillers.

[0049] Exemplary LCPs that can be used in films are thermoplastic polyester polymers comprising monomer units derived from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; thermoplastic polyester polymers comprising monomer units derived from 6-hydroxy-2-naphthoic acid, terephthalic acid, and acetaminophen; and thermoplastic polyester polymers comprising monomer units derived from 4-hydroxybenzoic acid, terephthalic acid, and 4,4'-biphenol.

[0050] Exemplary LCPs are available from Celanese Corporation under the trademark VECTRA®. These include VECTRA®A polymers (e.g., VECTRA®A950), VECTRA®B polymers (e.g., VECTRA®B950), and VECTRA®C polymers (e.g., VECTRA®C950).

[0051] VECTRA® A polyester is the chemical formula 73 mol% of monomer units derived from 4-hydroxybenzoic acid ("HBA") having, and chemical formula It contains 27 mol% of monomer units derived from 2,6-hydroxynaphthoic acid ("HNA") having

[0052] VECTRA® A950 has a melting point of approximately 278°C.

[0053] VECTRA®B polyester consists of 60 mol% monomer units derived from HNA, 20 mol% monomer units derived from TA, and the chemical formula It contains 20 mol% of monomer units derived from acetaminophenol having

[0054] VECTRA® B950 has a melting point of approximately 280°C.

[0055] VECTRA® C polyester contains 80 mol% monomer units derived from HBA and 20 mol% monomer units derived from HNA. VECTRA® C950 has a melting point of approximately 320 °C.

[0056] The total amount of LCP present in the composite material may be in the range of 40% to 95% by weight based on the total weight of the composition. In other embodiments, the total amount of LCP present in the composite material may be in the range of 50% to 85% by weight based on the total weight of the composition. In other embodiments, the total amount of LCP present in the composite material may be in the range of 60% to 85% by weight based on the total weight of the composition. In other embodiments, the total amount of LCP present in the composite material may be in the range of 70% to 80% by weight based on the total weight of the composition.

[0057] Exemplary fillers that may be included as one or more fillers in the LCP composite include zeolite, fused silica, talc, or a combination thereof. One or more fillers included in the LCP composite may have a low dielectric constant (Dk). One or more fillers included in the LCP composite film may be mechanically rigid, temperature-stable, and have a suitable size that allows them to bond with one or more LCPs in forming the LCP composite and to produce a desired product (e.g., film) without destroying the fillers (e.g., crushing, melting, etc.).

[0058] Generally, zeolites are microporous crystalline materials having pores of generally uniform molecular size and generally low theoretical dielectric constants. In some embodiments, aluminum, silicon, and oxygen are included in the framework of the zeolite (e.g., aluminosilicate zeolite). In other embodiments, silicon and oxygen are included in the framework of the zeolite (e.g., silica zeolite). In other embodiments, the zeolite may include one or more additional metals such as Ti, Sn, and / or Zn in addition to aluminum, silicon, and oxygen, or silicon and oxygen.

[0059] In some embodiments, the average pore diameters of the pores of the zeolite may be 2 nm or less. The pores may be a host of water molecules and / or ions. In other embodiments, the pores may contain air. Exemplary zeolites include Pentasil (MFI) zeolites available from Clariant AG. These include Pentasil (MFI) CZP 800, Pentasil (MFI) CZP 200, Pentasil (MFI) CZP 90, Pentasil (MFI) CZP 30, and Pentasil (MFI) CZP 27.

[0060] Fused silica is a glass composed of silica in an amorphous form. Examples include sol-gel silica and organic-templated mesoporous silica. Sol-gel silica provides the ability to adjust Dk values. Organic-templated mesoporous silica is a type of material that can provide more uniform pores than sol-gel silica (with a pore size range of up to about 100 nm) and has been shown to have promising Dk values.

[0061] Talc is a hydrous magnesium silicate mineral with the chemical composition of Mg3Si4O10(OH)2. The composition of talc is generally close to this generalized chemical formula, but some substitutions may occur. Small amounts of Al or Ti may replace Si; and small amounts of Fe, Mn, Al, and / or Ca may replace Mg.

[0062] The total amount of filler present in the LCP composite may be in the range of 5% to 60% by weight based on the total weight of the composition. In other embodiments, the total amount of filler present in the LCP composite may be in the range of 15% to 50% by weight based on the total weight of the composition. In other embodiments, the total amount of filler present in the LCP may be in the range of 15% to 40% by weight based on the total weight of the composition. In other embodiments, the total amount of filler present in the LCP composite may be in the range of 15% to 35% by weight based on the total weight of the composition. In other embodiments, the total amount of filler present in the LCP composite may be in the range of 15% to 30% by weight based on the total weight of the composition.

[0063] In some embodiments, the LCP composite may comprise one or more additives in addition to one or more liquid crystal polymers (“LCP” materials and one or more fillers. Exemplary fillers include pigments, carbon black, carbon fibers, glass fibers, etc. The total amount of additives present in the LCP composite may be in the range of 0.001 wt% to 5 wt% based on the total weight of the composition. In other embodiments, the total amount of additives present in the LCP composite may be in the range of 0.01 wt% to 3 wt% based on the total weight of the composition. In other embodiments, the total amount of additives present in the LCP composite may be in the range of 0.1 wt% to 1 wt% based on the total weight of the composition. In other embodiments, the LCP composite may not comprise one or more additives in addition to one or more liquid crystal polymers (“LCP” materials and one or more fillers.

[0064] An LCP composite can be formed by melting and combining one or more LCPs with one or more fillers. In some embodiments, when one or more LCP materials are melted and combined with one or more fillers, the LCP composite can be formed into pellets or other suitable forms that can be used as LCP composite resin in subsequent production of the product. In other embodiments, when one or more LCP materials are melted and combined with one or more fillers, the LCP composite can be used directly in the formation of the product. For example, the LCP composite can be formed into a film. The film can be formed by a melt extrusion process, an injection molding process, or other suitable processes. In an exemplary melt extrusion process, the LCP composite is extruded onto various casting rolls and cooled so that one or more LCPs of the LCP composite solidify, and the LCP composite is provided in the form of a film.

[0065] Similar to molecular weight, the amount and type of fillers can affect melt viscosity. For example, a pure resin with a viscosity of 21 Pa-s is compared to a high molecular weight resin with a viscosity of 27 Pa-s. The two resins are mixed with fillers (the pure resin is mixed with 24 wt% filler, and the high molecular weight resin is mixed with 20 wt% filler). The melt viscosity of the mixed resins is significantly affected: after mixing, the pure resin has a viscosity of 57 Pa-s, and after mixing, the high molecular weight resin has a viscosity of 36 Pa-s. All viscosity measurements were performed using a Dynsico LCR 7000 Capillary Rheometer with a barrel diameter of 0.376 inches, a die diameter of 0.762 mm, a die length of 30.48 mm, and a cone angle of 120 degrees at a melting temperature of 320 °C and a shear rate of 1800 (1 / sec). The melt viscosity can be adjusted to produce unprocessable synthetic materials, preferably maintained at less than 120 Pa-s. While it may be more desirable to maintain the melt viscosity at 80 Pa-s or less, it is also desirable to increase the viscosity for the pure resin to at least 90 Pa-s.

[0066] The “film” is a manufactured article having opposing surfaces extending in the length direction and the width direction orthogonal to the length direction, respectively, and the opposing surfaces are spaced apart from each other in the thickness direction orthogonal to the length direction and the width direction. FIG. 1 illustrates an exemplary LCP composite film (100) comprising opposing surfaces (102, 104).

[0067] Each of the main surfaces extends in the length direction (120) and in the width direction (122) orthogonal to the length direction. In embodiments where the film is produced by a process such as extrusion, the length direction may also be referred to as the longitudinal direction, and the width direction may also be referred to as the transverse direction. The main surfaces (102, 104) are spaced apart from each other in the thickness direction (124) orthogonal to the length direction (120) and the width direction (122).

[0068] In some embodiments, the LCP composite film is produced as a sheet having a given length and a given width. In other embodiments, the film is produced as a continuous roll having a given width, which can subsequently be cut to length.

[0069] LCP composite films may have mechanical properties that make them suitable for use as part of an antenna assembly.

[0070] For example, the thickness of the LCP composite film (in the thickness direction extending between the main surfaces of the film) may be in the range of 1 μm to 250 μm. In some embodiments, the thickness of the LCP composite film may be in the range of 10 μm to 200 μm. In other embodiments, the thickness of the LCP composite film may be in the range of 25 μm to 150 μm. In other embodiments, the thickness of the LCP composite film may be in the range of 25 μm to 100 μm. In other embodiments, the thickness of the film may be in the range of 25 μm to 50 μm. In some embodiments, the thickness tolerance of the LCP composite film is ±1 μm. In other embodiments, the thickness tolerance of the LCP composite film is ±0.05 μm.

[0071] The tensile modulus of the LCP composite can be measured according to IPC-TM-650 2.4.19 Tensile Strength and Elongation and ASTM D882, the entire disclosure of which is incorporated herein by reference. In some embodiments, the tensile modulus of the LCP composite film in the longitudinal and transverse directions is in the range of 50 MPa to 10 Gpa. In other embodiments, the tensile modulus of the LCP composite film in the longitudinal and transverse directions is in the range of 90 MPa to 10 Gpa. In other embodiments, the tensile modulus of the LCP composite film in the longitudinal and transverse directions is in the range of 98 MPa to 10 Gpa. In other embodiments, the tensile modulus of the LCP composite film in the longitudinal and transverse directions is in the range of 1 Gpa to 10 Gpa. In other embodiments, the tensile modulus of the LCP composite film in the longitudinal and transverse directions is in the range of 5 GPa to 10 GPa.

[0072] Elongation may be measured in accordance with IPC-TM-650 2.4.19 Tensile Strength and Elongation, the entire disclosure of which is incorporated herein by reference. In some embodiments, the balanced elongation of the LCP composite film in the longitudinal and transverse directions is in the range of 2% to 20%. In other embodiments, the balanced elongation of the LCP composite film in the longitudinal and transverse directions is in the range of 2% to 15%. In other embodiments, the balanced elongation of the LCP composite film in the longitudinal and transverse directions is in the range of 2% to 10%. In other embodiments, the balanced elongation of the LCP composite film in the longitudinal and transverse directions is in the range of 5% to 10%.

[0073] CTE (or dimensional stability) may be measured in accordance with IPC-TM-650 2.2.4 Dimensional Stability, the entire disclosure of which is incorporated herein by reference. In some embodiments, the coefficient of thermal expansion (CTE) of the LCP composite film in the longitudinal and transverse directions is in the range of -20 ppm / °C to 100 ppm / °C. In other embodiments, the coefficient of thermal expansion (CTE) of the LCP composite film in the longitudinal and transverse directions is in the range of 0 ppm / °C to 85 ppm / °C.

[0074] LCP composite films may possess electrical properties that make them suitable for use as part of an antenna assembly. For example, LCP composite films may possess low in-plane permittivity (Dk) and low loss tangent (tan(δ)) in the high-frequency range, making them suitable for use as part of an antenna assembly. The in-plane permittivity (Dk) and loss tangent (Df) of the formed LCP composite films may be measured according to ASTM D2520-13, the entire disclosure of which is incorporated herein by reference.

[0075] The “permittivity” (Dk) of a material is the (absolute) permittivity of the material expressed as a ratio to the electric constant (i.e., to the value of the absolute permittivity of a classical vacuum). This dimensionless quantity may also be referred to as “relative permittivity.”

[0076] "In-plane" permittivity (Dk) is the permittivity measured in the length direction (i.e., vertical direction) or width direction (i.e., horizontal direction) arranged along the field direction.

[0077] The loss tangent (tan(δ)) is a measure of the intrinsic electromagnetic energy dissipation of a material (absorption of electromagnetic waves by dielectric materials). The loss tangent can also be referred to as the dissipation factor (Df). A lower loss tangent indicates lower electromagnetic energy dissipation, which means less absorption of the original transmitted electromagnetic waves by the dielectric material. A higher loss tangent implies greater dielectric absorption, which means more absorption of the original transmitted electromagnetic waves by the dielectric material.

[0078] In some embodiments, the in-plane permittivity (Dk) of the LCP composite film in the longitudinal and transverse directions, respectively, at 10 GHz is in the range of 2.40 to 4.00. In other embodiments, the in-plane permittivity (Dk) of the LCP composite film in the longitudinal and transverse directions, respectively, at 10 GHz is in the range of 2.60 to 3.80. In other embodiments, the in-plane permittivity (Dk) of the LCP composite film in the longitudinal and transverse directions, respectively, at 10 GHz is in the range of 2.80 to 3.70. In other embodiments, the in-plane permittivity (Dk) of the LCP composite in the longitudinal and transverse directions, respectively, at 10 GHz is in the range of 2.80 to 3.50.

[0079] In some embodiments, the LCP composite may have a relatively constant in-plane permittivity (Dk) over a range of frequencies. For example, in some embodiments, the in-plane permittivity (Dk) of the LCP composite film in each of the longitudinal and transverse directions may be in the range of 2.40 to 4.00 over a frequency range of 1 GHz to 10 GHz. In other embodiments, the in-plane permittivity (Dk) of the LCP composite film in each of the longitudinal and transverse directions may be in the range of 2.60 to 3.80 over a frequency range of 1 GHz to 10 GHz. In other embodiments, the in-plane permittivity (Dk) of the LCP composite film in each of the longitudinal and transverse directions may be in the range of 2.80 to 3.70 over a frequency range of 1 GHz to 10 GHz. In other embodiments, the in-plane permittivity (Dk) of the LCP composite film in the longitudinal and transverse directions, respectively, may be in the range of 2.80 to 3.50 over a frequency range of 1 GHz to 10 GHz.

[0080] The LCP composite of the present disclosure may provide low anisotropy with respect to the dielectric constant (Dk) of the LCP composite film formed. In some embodiments, the ratio of the longitudinal dielectric constant (Dk) to the transverse dielectric constant (Dk) at 10 GHz for a film having a thickness of 10 μm to 200 μm is in the range of 1.0 to 1.4. In other embodiments, the ratio of the longitudinal dielectric constant (Dk) to the transverse dielectric constant (Dk) at 10 GHz for a film having a thickness of 10 μm to 200 μm is in the range of 1.0 to 1.35. In other embodiments, the ratio of the longitudinal dielectric constant (Dk) to the transverse dielectric constant (Dk) at 10 GHz for a film having a thickness of 10 μm to 200 μm is in the range of 1.0 to 1.25. In other embodiments, the ratio of the longitudinal permittivity (Dk) to the transverse permittivity (Dk) at 10 GHz for a film having a thickness of 10 µm to 200 µm is in the range of 1.0 to 1.20.

[0081] In some embodiments, the loss tangent (Df) of the LCP composite film in the longitudinal and transverse directions at 10 GHz is less than 0.00. In other embodiments, the loss tangent (Df) of the LCP composite film in the longitudinal and transverse directions at 10 GHz is in the range of 0.003 to 0.0001.

[0082] In some embodiments, the LCP composite may have a relatively constant loss tangent (Df) over a range of frequencies. For example, in some embodiments, the loss tangent (Df) of the LCP composite film in each of the longitudinal and transverse directions may be less than 0.003 over a frequency range of 1 GHz to 10 GHz. In other embodiments, the loss tangent (Df) of the LCP composite film in each of the longitudinal and transverse directions may be in the range of 0.003 to 0.0001 over a frequency range of 1 GHz to 10 GHz.

[0083] The LCP composite of the present disclosure may provide low anisotropy with respect to the loss tangent (Df) of the LCP composite film formed. In some embodiments, the ratio of the longitudinal loss tangent (Df) to the transverse loss tangent (Df) at 10 GHz for a film having a thickness of 10 μm to 200 μm is in the range of 0.2 to 1.0. In other embodiments, the ratio of the longitudinal loss tangent (Df) to the transverse loss tangent (Df) at 10 GHz for a film having a thickness of 10 μm to 200 μm is in the range of 0.5 to 1.0.

[0084] Examples - LCP composite films

[0085] LCP films are formed by melt extrusion. Pure LCP resin is melted, combined with a filler, and extruded to a predetermined thickness. Table 1 shows the respective compositions and thicknesses of the extruded films.

[0086]

[0087] Table 2 shows the electrical properties of the LCP composite examples described in Table 1. The in-plane permittivity (Dk) and loss tangent (Df) of the formed LCP composite films are measured according to IPC-TM-650 2.5.5.3 (or ASTM D2520-13 - confirm) permittivity (dielectric constant) and loss tangent (dissipation factor), the entirety of which is included herein by reference. Each specimen of Examples 1 through 10 was tested according to such testing procedures, and the results are shown in the table. The films are measured as a function of frequency, and Table 2 shows the average permittivity (Dk) of the examples at 10 GHz. Film specimens of Examples 1 and 2 were also tested to measure the dissipation factor (Df) in both the longitudinal and transverse directions, and Table 2 shows the average dissipation factor (Df) of the examples at 10 GHz.

[0088]

[0089] The in-plane permittivity (Dk) with respect to frequency was measured in the frequency range of 2 GHz to 11 GHz. The in-plane permittivity (Dk) in the longitudinal and transverse directions remains relatively constant.

[0090] Table 3 shows the tensile moduli of Examples 1 through 4 described in Table 1. Tensile moduli are measured according to IPC-TM-650 2.4.19 Tensile Strength and Elongation. Each of the specimens of Examples 1 through 4 was tested according to such testing procedures, and the results are shown in the table.

[0091]

[0092] Table 4 shows the coefficient of thermal expansion (CTE) of Examples 1 through 4 described in Table 1. CTE (or dimensional stability) is measured according to IPC-TM-650 2.2.4 Dimensional Stability. Each sample of Examples 1 through 4 was tested according to such testing procedures, and the results are shown in the table.

[0093]

[0094] Table 5 shows the elongation of the examples described in Table 1. Elongation is measured according to IPC-TM-650 2.4.19. Each sample of Examples 1 through 4 was tested according to such testing procedures, and the results are shown in Table 1.

[0095]

[0096] Now, referring to FIGS. 4 and 5, the metal-clad laminate may comprise the LCP composite film of the present disclosure. The metal-clad laminate may comprise a structure in which one or more metal-clad layers are laminated to the LCP composite film. FIG. 2 illustrates an exemplary embodiment in which one metal-clad layer (150) is provided on one main surface (102) of the LCP composite film and another metal-clad layer (152) is provided on the other main surface (104) of the LCP composite film (100). FIG. 3 illustrates an exemplary embodiment in which one metal-clad layer (150) is provided on one main surface (102) of the LCP composite film (100).

[0097] The metal-clad laminate may include a third component layer comprising a film laminated within the metal-clad laminate to provide functionality. The third component layer (not shown) may include polytetrafluoroethylene, glass-reinforced epoxy laminate films such as FR-4, polyimide films, and combinations thereof. The functionality provided by such a third component layer may provide a metal-clad laminate capable of functioning as a printed circuit board.

[0098] Exemplary metals that can be used in one or more metal-clad layers include one or more electrically conductive metals such as copper, aluminum, copper alloys, aluminum alloys, etc. Exemplary coppers include MHT copper and rolled annealed (RA) copper. One or more metals can provide excellent adhesion to the LCP composite. In embodiments having one or more metal-clad layers, the material of one metal-clad layer may be the same as or different from the material of the other clad layer(s). RA copper foils are manufactured by a rolling process after copper is cast into a block, whereas ED copper foils are manufactured by a galvanic process in which copper is deposited onto a rotating drum. RA copper foils can be rolled to desired thicknesses of 6 to 500 microns. Each surface is preferably smooth but can be roughened. ED copper foils have rough and smooth surfaces and generally have a thickness of 6 to 25 microns. In some embodiments, the roughness of the surface adjacent to the LCP composite film may be selected to be less than 5 microns or 3 microns or less, as measured by the methods described in JIS B 0601-2001 (10-point average roughness).

[0099] In some embodiments, the thickness of the metal clad layer is in the range of 5 µm to 50 µm. In other embodiments, the thickness of the metal clad laminate (e.g., copper) is in the range of 10 µm to 40 µm. In other embodiments, the thickness of the metal clad laminate is in the range of 10 µm to 30 µm. In other embodiments, the thickness of the metal clad laminate is in the range of 10 µm to 20 µm. In some embodiments having one or more metal clad layers, the thickness of one metal clad layer may differ from the thickness of the other clad layer(s). In other embodiments having one or more metal clad layers, the thickness of the metal clad layers may be the same.

[0100] In an exemplary lamination process, a metal-clad laminate can be produced by preheating platens, placing a stack of an LCP composite film and one or more metal layers between the platens, and applying a predetermined amount of pressure to the layers while heating the layers to a predetermined temperature to form a laminate. After a predetermined time, the formed laminate can be removed from the platens and cooled. In some embodiments, the predetermined temperature is greater than 225 °C and less than 325 °C. In other embodiments, the predetermined temperature is greater than 250 °C and less than 300 °C. In other embodiments, the predetermined temperature is greater than 250 °C and less than 300 °C. In some embodiments, the predetermined pressure used in the lamination process is greater than 0.25 ton and less than 5 ton. In other embodiments, the predetermined pressure is greater than 0.75 ton and less than 4.25 ton. The temperature and pressure used can allow the LCP composite film to be laminated onto one or more metal layers, but can be low enough to avoid melting the LCP composite to the extent that it causes leakage from the lamination.

[0101] The formed laminate may subsequently undergo one or more post-forming steps. For example, the metal clad layer(s) may be etched to form a metal layer of a desired shape. The laminate may be rinsed after etching.

[0102] Such lamination may include a release layer placed between the pressure plates and the adjacent film to minimize adhesion of the film to the pressure plates. Such release layers are designed to maintain a smooth surface of the film and allow heat flow from the pressure plates to the film. The lamination method can be used to manufacture a single metal-clad laminate as shown in FIG. 3, or a double metal-clad laminate as shown in FIG. 2. The double metal-clad laminate can be converted into a single metal-clad laminate by partially or wholly etching one of the outer metal layers.

[0103] In one embodiment of the lamination process, a single-clad laminate is formed by combining film extrusion with a calendering process. Referring to FIG. 6, a general arrangement of a film extruder (310) having an associated extrusion die (320) is shown. The extrusion die (320) includes a flat die capable of producing a flat liquid film of LCP with a desired thickness and width through die bolt adjustments. The extruder serves to produce a flat LCP film in the form of a hot melt curtain (330).

[0104] A metal foil substrate (340) is positioned adjacent to a calendar (350) comprising both a first roll (351) and a second roll (352). The first roll (351) and the second roll (352) are positioned adjacent to each other to create a minimum roll separation region, which is referred to as a nip region (353). In the nip region (353), the first and second roll surfaces are nearly parallel. The rolls may be deflected relative to each other to create pressure in the nip region (353). The second roll includes a heated surface capable of transferring heat to substrates transferred over its surface.

[0105] The metal foil (340) is heated by being placed on the second roll (352) while tension is applied to remove and prevent wrinkles in the foil. The surface temperature of the second roll is variable and can be varied above 180°C to heat the metal foil to a temperature in the range of 180 to 220°C. As the metal foil (340) is heated by the second roll (352), it enters the nip area and meets the hot molten curtain that is created by the extrusion die (320) and extends through gravity to the nip area (353).

[0106] The high-temperature metal curtain (330) aligns with the metal foil in the nip area and creates a molten pool (not shown) calendered between two calender rolls, so that the thickness of the single metal-clad laminate (360) is formed in the nip area.

[0107] The calendar (350) further includes a third roll (354) capable of pulling a single metal-clad laminate (360) from the nip area. Post-calendering operations may further include measuring the laminate thickness, trimming the laminate, and winding.

[0108] One embodiment of the lamination process is thickness uniformity generated in both machine and cross-machine directions. Changes in the gap region due to the dimensions of the rolls, thermal effects, and roll distortions caused by high pressures that may occur in the gap can result in product non-uniformity in the cross-machine direction. Roll vibration and feed uniformity, as well as the eccentricity of the rolls relative to the roll shaft, must be strictly controlled to prevent non-uniformity in the machine direction. The uniform gap size can be distorted during operation due to hydrodynamic forces generated in the nip region that deflect the rolls. Under such conditions, the resulting laminate is thick in the middle and thin at the edges. Accordingly, the rolls (351 and 352) are ground, hardened, and polished, and the roll cross diameter is maintained within 5 microns for every 50 mm along each roll. The roll surfaces are coated with a diamond-like coating (DLC) having high hardness and high release properties, and are maintained at 0.2 micron Ra after coating. The maximum nip force is maintained in a nip area of ​​0.13 kN / mm between the rolls to produce a 65-micron thick laminate consisting of a metal foil 12 to 35 micron thick and an LCP film 50 micron thick.

[0109] In some embodiments, the ratio of the dielectric constant (Dk) in the longitudinal direction to the dielectric constant (Dk) in the transverse direction at 10 GHz of an LCP composite film included in a metal-clad laminate having a thickness of 10 µm to 200 µm is in the range of 1.0 to 1.2. In other embodiments, the ratio of the dielectric constant (Dk) in the longitudinal direction to the dielectric constant (Dk) in the transverse direction at 10 GHz of an LCP composite film included in a metal-clad laminate having a thickness of 10 µm to 200 µm is in the range of 1.0 to 1.1. In other embodiments, the ratio of the dielectric constant (Dk) in the longitudinal direction to the dielectric constant (Dk) in the transverse direction at 10 GHz of an LCP composite film included in a metal-clad laminate having a thickness of 10 µm to 200 µm is in the range of 1.0 to 1.05.

[0110] The low anisotropy of metal-clad laminates allows them to be used in communication applications, such as, for example, as part of an antenna assembly.

[0111] The in-plane permittivity (Dk) of an LCP contained in a metal-clad laminate can be measured according to the measurement methods presented in Oliver et al.’s “Round Robin of High Frequency Test Methods by the IPC-D24C Task Group,” the entire disclosure of which is incorporated herein by reference. Oliver et al. presented other exemplary microstrip transmission line measurement methods, including extraction from impedance, group delay extraction from phase, and differential phase length; In addition, methods for measuring free space transmission, methods including perturbed resonant cavities with electric field oriented in-plane of dielectric, and methods including aperture-coupled stripline with electric field oriented normal to plane of dielectric are presented. Metal-clad laminates including LCP composite films may also be measured according to IPC-TM-650 2.5.5.3, IPC-TM-650 2.5.5.9, and IPC-TM-650 2.5.5.5, the entire contents of which are incorporated herein by reference.

[0112] The CTE of the LCP composite film included in the metal-clad laminate can be measured in accordance with IPC-TM-650 2.2.4 Dimensional Stability, the entire disclosure of which is incorporated herein by reference. In some embodiments, the ratio of the longitudinal CTE to the transverse direction (MD / TD) of the LCP composite film included in the metal-clad laminate is in the range of 0.01 to 1.0. In other embodiments, the ratio of the longitudinal CTE to the transverse direction (MD / TD) of the LCP composite film included in the metal-clad laminate is in the range of 0.2 to 0.8. In other embodiments, the ratio of the longitudinal CTE to the transverse direction (MD / TD) of the LCP composite film included in the metal-clad laminate is in the range of 0.4 to 0.7.

[0113] The peel strength of the metal-clad laminate can be measured in accordance with IPC-TM-650 2.4.9 Peel Strength, Flexible Dielectric Materials, the entire disclosure of which is incorporated herein by reference. In some embodiments, where the metal clad is MHT copper, the peel strength of MHT copper from the LCT composite film is in the range of 6.0 to 13.0 lb / in. In other embodiments, where the metal clad is MHT copper, the peel strength of MHT copper from the LCT composite film is in the range of 8.0 to 12.0 lb / in. In some embodiments, where the metal clad is RA copper, the peel strength of RA copper from the LCT composite film is in the range of 4.0 to 10.0 lb / in. In other embodiments, when the metal clad is RA copper, the peel strength of RA copper from the LCT composite film is in the range of 5.0 to 8.0 lb / in.

[0114] Examples - Metal-clad laminates including LCP composite films

[0115] LCP composite films produced according to Examples 4 and 5 are laminated with RA copper having a thickness of 12 μm. To ensure that the layers of the metal-clad laminate resemble the stack shown in FIG. 2, LCP composite films are laminated with a layer of RA copper on each main surface. Lamination is performed using a predetermined amount of pressure and a predetermined temperature to form the laminate. The specific pressures and temperatures used for each lamination process are shown in FIG. 6.

[0116] Exemplary metal-clad laminates comprising LCP composite films are tested in accordance with IPC-4204 and IPC-4204A, the entirety of which is incorporated herein by reference. The specification sheet IPC-4202 / 24 incorporated herein relates to the testing of copper-clad liquid crystal polymers.

[0117] Table 6 presents the in-plane permittivity (Dk) of metal-clad laminates formed including an LCP composite film. The in-plane permittivity (Dk) of metal-clad laminates including an LCP composite film is measured by extraction from the microstrip transmission line method—impedance—as presented in Oliver et al.’s “Round robin of high-frequency test methods by the IPC-D24C task group.”

[0118]

[0119] FIG. 4 shows the XRD analysis results of the unlaminated and laminated samples of Example 4 compared with a sample of a commercially available liquid crystal polymer used in radio frequency circuits (“Comparative Example”). The sample of the Comparative Example is also laminated with RA copper having a thickness of 12 μm. As shown, the unlaminated sample of Example 4 includes a profile in which peaks are provided at 90° and -90°. For the samples of Example 5 laminated at 270 °C, these peaks are significantly reduced.

[0120] Table 7 presents the coefficient of thermal expansion (CTE) of metal-clad laminates formed including the LCP composite film produced according to Example 4. The CTE is measured according to IPC-TM-650 dimensional stability. Samples of metal-clad laminates including the LCP composite film produced according to Example 4 were tested according to such testing procedures, and the results are shown in the table.

[0121]

[0122] Table 8 presents the peel strength of metal-clad laminates containing LCP composite films produced according to Examples 1 through 7, and comparative metal-clad laminates produced using comparative examples. Each example was laminated to make two 11-inch x 7-inch clads. One was 1 ounce of MHT copper. The other was 1 ounce of RA copper. Peel strength is measured according to IPC-TM-650 2.4.9 Peel Strength, Flexible Dielectric Materials. Each sample of Examples 1 through 7 was tested according to such testing procedures, and the results are shown in the table.

[0123]

[0124] The results from Table 8 show improved peel strength of metal-clad laminates containing LCP composite films produced according to Examples 1 through 7 compared to metal-clad laminates produced using comparative examples. The improved adhesion provided by metal-clad laminates containing LCP composite films allows for the use of RA copper, which is smoother and harder to bond than MHT copper.

[0125] Although the present invention has been illustrated and described in relation to specific embodiments or examples, it will be apparent to those skilled in the art from reading and understanding this specification and the accompanying drawings that equivalent changes and modifications may occur. In particular, with respect to the various functions performed by the elements described above (components, assemblies, devices, components, etc.), terms used to describe such elements (including references to “means”) are intended to be opposed to any element that performs the designated function of the described element (i.e., is functionally equivalent), even if it is not structurally equivalent to the disclosed structure performing the function in the exemplary embodiments or examples of the present invention illustrated herein, unless otherwise indicated. Furthermore, while specific features of the present invention have been described with respect to only one or more of the multiple illustrated embodiments, such features may be combined with one or more other features of other embodiments that may be desired and advantageous for any given or specific application.

Claims

Claim 1 A liquid crystal polymer composite film formed from a resin composite, wherein the resin composite comprises: one or more liquid crystal polymers present in an amount ranging from 40% by weight to 95% by weight based on the total weight of the liquid crystal polymer composite; and one or more porous fillers present in an amount ranging from 5% by weight to 60% by weight based on the total weight of the liquid crystal polymer composite, comprising at least one of a zeolite having an average pore diameter of 2 nm or less and a mesoporous silica having a pore size up to 100 nm, wherein the thickness of the liquid crystal polymer composite film is in the range of 10 μm to 200 μm, and the ratio of the in-plane dielectric permittivity in the machine direction of the liquid crystal polymer composite film to the in-plane dielectric permittivity in the transverse direction of the liquid crystal polymer composite film is in the range of 1.0 to 1.4 in the frequency range of 1 GHz to 10 GHz. Claim 2 A liquid crystal polymer composite film according to claim 1, wherein the ratio of the loss tangent in the longitudinal direction of the liquid crystal polymer composite film to the loss tangent in the transverse direction of the liquid crystal polymer composite film is in the range of 0.2 to 1.0 in the frequency range of 1 GHz to 10 GHz. Claim 3 A liquid crystal polymer composite film according to claim 1 or 2, wherein the one or more liquid crystal polymers comprise a polymer comprising monomer units derived from 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid. Claim 4 A liquid crystal polymer composite film according to claim 1 or 2, wherein the one or more liquid crystal polymers comprise a polymer comprising monomer units derived from 4-hydroxybenzoic acid. Claim 5 delete Claim 6 A liquid crystal polymer composite film according to claim 1 or 2, wherein the melt viscosity of the resin composite at a melting temperature of 320 ℃ and a shear rate of 1800 (1 / sec) is 30 Pa-s or more and less than 120 Pa-s. Claim 7 A liquid crystal polymer composite film according to claim 1 or 2, wherein the melt viscosity of the resin composite at a melting temperature of 320 ℃ and a shear rate of 1800 (1 / sec) is 36 Pa-s or more and less than 80 Pa-s, and the thickness of the liquid crystal polymer composite film is in the range of 10 μm to 100 μm. Claim 8 A liquid crystal polymer composite film according to claim 1 or 2, wherein the melt viscosity of the resin composite at a melting temperature of 320 ℃ and a shear rate of 1800 (1 / sec) is 36 Pa-s or more and less than 57 Pa-s, and the thickness of the liquid crystal polymer composite film is in the range of 10 μm to 100 μm. Claim 9 A liquid crystal polymer composite film according to claim 1 or 2, wherein the thickness of the liquid crystal polymer composite film is in the range of 25 μm to 200 μm. Claim 10 A metal-clad laminate comprising: the liquid crystal polymer composite film of claim 1 or 2; and a metal layer laminated to the main surface of the liquid crystal polymer composite film, wherein the ratio of the in-plane dielectric constant in the longitudinal direction of the liquid crystal polymer composite film to the in-plane dielectric constant in the transverse direction of the liquid crystal polymer composite film is in the range of 0.9 to 1.2 in a frequency range of 1 GHz to 10 GHz. Claim 11 In claim 10, the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the in-plane permittivity in the transverse direction of the liquid crystal polymer composite film is in the range of 0.9 to 1.1 in the frequency range of 1 GHz to 10 GHz, a metal-clad laminate. Claim 12 In claim 10, the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the in-plane permittivity in the transverse direction of the liquid crystal polymer composite film provided in the metal-clad laminate is smaller than the ratio of the in-plane permittivity in the longitudinal direction of the liquid crystal polymer composite film to the in-plane permittivity in the transverse direction of the liquid crystal polymer composite film prior to lamination, metal-clad laminate. Claim 13 A metal-clad laminate according to claim 10, wherein the metal is copper, and the roughness of the copper surface is less than 5 microns when measured by Rz 10-point mean roughness. Claim 14 In claim 13, the peel strength of the copper in the liquid crystal polymer composite film is in the range of 6.0 to 13.0 lb / in, metal-clad laminate. Claim 15 A metal-clad laminate according to claim 10, wherein the metal is copper, and the roughness of the copper surface is 3 microns or less when measured by an unknown 10-point average roughness. Claim 16 In claim 15, the copper is MHT copper, and the peel strength of the MHT copper in the liquid crystal polymer composite film is in the range of 4.0 to 10.0 lb / in, metal-clad laminate. Claim 17 A metal-clad laminate according to claim 10, further comprising an additional metal-clad layer laminated to an additional main surface of the liquid crystal polymer composite film. Claim 18 In claim 10, the ratio of the coefficient of thermal expansion of the liquid crystal polymer composite film in the longitudinal direction (MD / TD) to the transverse direction is in the range of 0.9 to 1.0, a metal-clad laminate. Claim 19 In claim 10, the thickness of the laminate is in the range of 15 μm to 50 μm, and the laminate is a flexible metal-clad laminate. Claim 20 In claim 10, the thickness of the laminate is in the range of 50 μm to 200 μm, and the laminate is a rigid metal-clad laminate. Claim 21 A method for manufacturing a metal-clad laminate, wherein the metal-clad laminate comprises a liquid crystal polymer composite film of claim 1 or 2 and a metal layer laminated to the main surface of the liquid crystal polymer composite film, wherein the liquid crystal polymer composite film has a relative permittivity of less than 3.1, and the method comprises the steps of: positioning the metal layer adjacent to a calender comprising first and second rolls positioned in a parallel configuration to form a nip region bounded by the surfaces of the first and second rolls; positioning an extruder having the extrusion die in a straight line with the calender such that the extrusion die is positioned above the nip region; heating the metal layer and moving the heated metal layer to the nip region; and extruding the liquid crystal polymer composite film - a melt curtain exiting the extrusion die and entering the nip region -; A method comprising the step of laminating the liquid crystal polymer composite film and the metal layer in the nip region to produce the metal-clad laminate. Claim 22 In claim 21, a method wherein, in the step of heating the metal layer, the metal layer is heated at a temperature in the range of 180 to 220°C. Claim 23 In claim 22, in the step of heating the metal layer, the second roll is heated at a temperature in the range of 180 to 220°C. Claim 24 In claim 21, a method wherein, in the step of positioning the metal layer, the first and second rolls are deflected relative to each other to generate a nip force in the nip area when the metal layer and the molten curtain flow. Claim 25 In claim 24, the method wherein the nip force is maintained in the range of 0 to 0.13 kN / mm. Claim 26 In claim 21, a method wherein, in the step of laminating the liquid crystal polymer composite film, a melt pool is formed from the melt curtain in the nip area, the melt pool is calendered between the two rolls, and the thickness of the metal-clad laminate is determined by the distance between the two rolls. Claim 27 In claim 26, the thickness of the metal foil is in the range of 12 to 35 microns, and the thickness of the liquid crystal polymer composite film is in the range of 40 to 100 microns. Claim 28 In claim 27, the method wherein the thickness of the liquid crystal polymer composite film is 50 microns. Claim 29 delete

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