Patent Application
20250187308
The present invention relates to a laminate.
The speed and capacity of signals in mobile communication devices such as mobile phones, network infrastructure devices such as servers and routers, and electronic apparatuses such as large computers have been increased year by year, and particularly, a rapid growth of fifth generation mobile communication systems (5G) is expected. For example, a high-frequency circuit board (for example, a printed wiring board such as a rigid substrate and a flexible substrate) is mounted on these electronic apparatuses. In addition, in recent years, as an application using such a high-frequency signal, a new system using a high-frequency wireless signal is put into practical use and a practical plan is made in the field of intelligent transport systems (ITS) (for example, automobile and transportation system-related) and the field of short-range communication indoors, and the high-frequency circuit board is also used for these devices and the like.
As a polymer constituting the polymer layer, for example, JP2018-066018A discloses “polyarylate resin containing a divalent phenol residue represented by General Formula (1) and an aromatic divalent carboxylic acid residue represented by General Formula (2) and General Formula (3)”.
A laminate used for a high-frequency circuit board or the like is required to have excellent low dielectric characteristics and excellent low water absorption. In addition, it is also required that adhesiveness between the polymer layer and the copper layer is excellent.
As a result of studying the invention disclosed in JP2018-066018A, the present inventors have found that it is difficult to achieve a balance between low dielectric characteristics, low water absorption, and adhesiveness.
Therefore, an object of the present invention is to provide a laminate having excellent low dielectric characteristics, low water absorption, and adhesiveness.
As a result of intensive studies on the above-described objects, the present inventors have found that the above-described objects can be accomplished by the following configurations.
A laminate comprising:
The laminate according to [1],
The laminate according to [1] or [2],
The laminate according to any one of [1] to [3],
According to the present invention, it is possible to provide a laminate having excellent low dielectric characteristics, low water absorption, and adhesiveness.
In the present specification, numerical ranges represented by “to” include numerical values before and after “to” as lower limit values and upper limit values.
The laminate according to the embodiment of the present invention includes a copper layer and a polymer layer, in which the polymer layer contains a polyarylate, and the polyarylate has at least one repeating unit I selected from the group consisting of a repeating unit represented by Formula (I-A), a repeating unit represented by Formula (I-B), and a repeating unit represented by Formula (I-C), and has a repeating unit II represented by Formula (II).
The laminate according to the embodiment of the present invention includes a polymer layer containing the specific polyarylate.
Hereinafter, each member which can be included in the laminate will be described in detail.
The laminate includes a copper layer.
Examples of the copper layer include a rolled copper foil and an electrolytic copper foil.
The copper layer may have a wiring pattern.
A surface roughness Rz of the copper layer (preferably, the interface with the polymer layer) is preferably 2.0 μm or less, and more preferably 1.0 μm or less. The lower limit thereof is preferably 0.01 μm or more.
The laminate includes a polymer layer containing the specific polyarylate.
In Formula (I-A), R1 represents a branched alkyl group having 4 or more carbon atoms.
In Formula (I-A), R1 represents a branched alkyl group having 4 or more carbon atoms.
In Formula (I-A), R2 represents a hydrogen atom, a linear alkyl group, or an aryl group which may have a substituent.
In Formula (I-A), R3 represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent.
In Formula (I-A), R1 and R2 are not bonded to each other to form a ring structure.
As the repeating unit represented by Formula (I-A), a repeating unit represented by Formula (I-Aa) is preferable.
In Formula (I-B), R4 represents a hydrogen atom, a linear alkyl group, or an aryl group which may have a substituent.
In Formula (I-B), R4 represents a hydrogen atom, a linear alkyl group, or an aryl group which may have a substituent.
In Formula (I-B), n represents an integer of 2 to 20.
In Formula (I-C), R6 and R7 represent a hydrogen atom, an alkyl group, or an aryl group which may have a substituent.
Specific examples of the repeating unit represented by Formula (I-A) are shown below. In the formulae, Me represents a methyl group.
Specific examples of the repeating unit represented by Formula (I-B) are shown below. In the formulae, Me represents a methyl group.
Specific examples of the repeating unit represented by Formula (I-C) are shown below.
A content of the repeating unit I in the specific polyarylate is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and particularly preferably 40% by mass or more with respect to the total mass of the specific polyarylate. The upper limit thereof is preferably 70% by mass or less, and more preferably 60% by mass or less with respect to the total mass of the specific polyarylate.
The specific polyarylate has a repeating unit II represented by Formula (II).
In Formula (II), Rc represents an alkyl group, an aryl group which may have a substituent, or a halogen atom.
The alkyl group represented by Rc and the aryl group which may have a substituent, represented by Rc, are each the same as the alkyl group represented by R3 and the aryl group which may have a substituent, represented by R3; and suitable aspects thereof are also the same.
A content of the repeating unit II in the specific polyarylate is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and particularly preferably 40% by mass or more with respect to the total mass of the specific polyarylate. The upper limit thereof is preferably 70% by mass or less, and more preferably 60% by mass or less with respect to the total mass of the specific polyarylate.
The specific polyarylate may have other repeating units in addition to the above-described repeating units.
A content of the other repeating units in the specific polyarylate is preferably 10% to 60% by mass, more preferably 20% to 50% by mass, and still more preferably 30% to 50% by mass with respect to the total mass of the specific polyarylate.
The specific polyarylate preferably has a crosslinking structure.
A weight-average molecular weight of the specific polyarylate is preferably 50,000 to 250,000, more preferably 80,000 to 180,000, and still more preferably 100,000 to 150,000.
The specific polyarylate may be used alone or in combination of two or more kinds thereof.
The polymer layer may contain a liquid crystal polymer.
The liquid crystal polymer may be a thermotropic liquid crystal polymer which exhibits liquid crystallinity in a molten state.
The liquid crystal polymer preferably has a repeating unit represented by any of Formulae (LC1) to (LC4).
In Formula (LC2), Ar1 represents a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, or a phenanthryl group, each of which may have a substituent.
A content of the repeating unit represented by Formula (LC1) is preferably 10 to 80 mol % and more preferably 50 to 65 mol % with respect to the total mass of the liquid crystal polymer.
The liquid crystal polymer may have a particle shape.
A melting point of the liquid crystal polymer is preferably 300° C. or higher, more preferably 305° C. or higher, and still more preferably 310° C. or higher. The upper limit thereof is preferably 350° C. or lower, more preferably 345° C. or lower, and still more preferably 340° C. or lower.
The liquid crystal polymer may be used alone or in combination of two or more kinds thereof.
The polymer layer may contain other polymers in addition to the specific polyarylate.
A thickness of the polymer layer is preferably 1 to 100 μm and more preferably 2 to 60 μm.
In a case where the laminate includes a single polymer layer, the laminate is preferably a laminate including the copper layer and the single polymer layer in this order (hereinafter, also referred to as “laminate X”). In other words, the laminate X has a configuration in which the single polymer layer is provided on the copper layer, and has a two-layer structure as a whole. The single polymer layer in the laminate X contains the specific polyarylate.
Examples of a suitable aspect of the laminate X include an aspect X.
In a case where the laminate includes a multi-polymer layer, the laminate is preferably a laminate including the copper layer and the multi-polymer layer in this order (hereinafter, also referred to as “laminate Y”). In other words, the laminate Y has a configuration in which the multi-polymer layer is provided on the copper layer, and has a multilayer structure of three or more layers as a whole. Among the multi-polymer layers in the laminate Y, at least a polymer layer (first polymer layer) in direct contact with the copper layer contains the specific polyarylate.
Examples of a suitable aspect of the laminate Y include an aspect Y1 to an aspect Y8.
Aspect Y6: a laminate including a copper layer, a first polymer layer, a second polymer layer, and a third polymer layer in this order, in which the first polymer layer contains a first specific polyarylate, the second polymer layer contains a liquid crystal polymer, and the third polymer layer contains a second specific polyarylate;
A production method of the specific polyarylate is not particularly limited, and a known production method may be used.
The production method of the specific polyarylate may include a method A.
In the method A, as a water phase, an alkaline aqueous solution of dihydric phenol is prepared, and then a polymerization catalyst is added thereto.
The method A has three advantages.
In the method A in the production method of the specific polyarylate, from the viewpoint of enhancing characteristics of the obtained specific polyarylate, it is preferable to use, as the dihydric phenol component, a monomer from which the above-described repeating unit I is derived.
From the viewpoint of workability during the production, it is preferable that the solid 4,4′-biphenyldicarbonyl chloride does not contain an organic solvent.
In the interfacial polymerization of the production method of the specific polyarylate, from the viewpoint of enhancing characteristics of the obtained specific polyarylate and controlling the molecular weight during polymerization, it is preferable to use a compound represented by Formula (S) together with the dihydric phenol.
H—O—Ra (S)
In Formula (S), Ra represents a monovalent organic group.
In the production method of the specific polyarylate, post treatment in the method for producing the above-described polymer may be carried out.
Examples of the production method of the specific polyarylate include a production method of polycondensing a monomer from which the repeating unit I is derived, a monomer from which the repeating unit II is derived, and as necessary, other monomers by a conventional method.
Examples of a method of polycondensing the above-described monomers include a method of polycondensing by an interfacial polymerization method, a solution polymerization method, and the like; and an interfacial polymerization method is preferable.
In the above-described production method of the specific polyarylate, a method B may be used.
In the above-described production method of the specific polyarylate, a method C may be used.
In the interfacial polymerization, from the viewpoint of controlling the molecular weight of the specific polyarylate, a terminal blocking agent may be used during the polymerization. In addition, from the viewpoint of controlling characteristics of the specific polyarylate, it is preferable that the terminal of the above-described specific polyarylate is sealed with a monohydric phenol, a monovalent acid chloride, a monohydric alcohol, a monovalent carboxylic acid, or the like.
Examples of the polymerization catalyst of the interfacial polymerization include quaternary ammonium salts such as tributylbenzylammonium halide, tetrabutylammonium halide, trimethylbenzylammonium halide, and tricthylbenzylammonium halide; and quaternary phosphonium salts such as tributylbenzylphosphonium halide, tetrabutylphosphonium halide, trimethylbenzylphosphonium halide, and tricthylbenzylphosphonium halide.
Examples of the organic solvent of the organic phase in the interfacial polymerization include chlorine-based solvents such as dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, 1,1,2,2-tetrachloroethane, 1,1,1-trichlorocthane, o-dichlorobenzene, m-dichlorobenzene, and p-dichlorobenzene; aromatic hydrocarbons such as toluene, benzene, xylene, and anisole; and tetrahydrofuran.
Acetic acid is added to the specific polyarylate solution obtained after the polymerization to terminate the polymerization, and then the specific polyarylate solution is repeatedly stirred and washed with water to remove ionic components such as sodium ions, potassium ions, lithium ions, chloride ions, and polymerization catalyst, which are contained in the specific polyarylate solution. The water used for washing may be acidic or basic, and the washing is repeatedly performed until the washing waste water is neutral.
By adding dropwise the obtained specific polyarylate solution to a poor solvent, the specific polyarylate as a solid content is precipitated. A concentration of solid contents of the specific polyarylate solution is preferably 7% by mass or less. In addition, it is preferable that the volume of the poor solvent is 3 times or more the volume of the polymer solution. Examples of the poor solvent include methanol, ethanol, isopropyl alcohol, acetone, acetonitrile, and hexane.
By adding the specific polyarylate solution to the poor solvent, it is possible to reduce residual monomers, the alkali, and impurities derived from the polymerization catalyst, which are contained in the specific polyarylate. In order to reduce the content of the residual monomers and the impurities, it is particularly preferable that the immersion time in the poor solvent after the precipitation treatment in the poor solvent is 1 minute or longer. In addition, in a case where trimethylbenzylammonium halide, tricthylbenzylammonium halide, or the like, which has a relatively low polymerization activity, is used as the polymerization catalyst, it is preferable that the immersion time is 3 minutes or longer. In order to reduce the residual monomers and the impurities, the above-described operation of dissolving the obtained specific polyarylate in a solvent again and adding the solution to the poor solvent for precipitation may be repeated.
In a case of producing the above-described specific polyarylate, impurities insoluble in tetrahydrofuran or dichloromethane may be generated. One of causes is considered to be that 4,4′-biphenyldicarbonyl chloride or the like is used for introducing the repeating unit represented by Formula (II) described above. That is, it is considered that, in a case where 4,4′-biphenyldicarboxylic acid or 4-(4-carboxyphenyl)-benzoyl chloride, that is an impurity which can be contained in the 4,4′-biphenyldicarbonyl chloride, is brought into the production process of the above-described specific polyarylate, as shown in the following scheme, an acid anhydride compound is formed as the insoluble impurity.
It is preferable that the polymer layer does not contain such insoluble impurities. Examples of a method of obtaining a specific polyarylate containing no insoluble impurities include a method in which a solution containing the polymer and the insoluble impurities is treated with various adsorbents to remove the insoluble impurities.
Examples of a manufacturing method of the laminate include a known manufacturing method.
It is also preferable that the manufacturing method of the laminate includes a step of melting a polymer (for example, the specific polyarylate, the liquid crystal polymer, and the like) to form a polymer layer, and a step of bonding the obtained polymer layer and a copper layer.
The composition for forming a polymer layer is a composition used for forming the polymer layer.
Examples of the solvent include chlorine-based solvents such as dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, 1,1,2,2-tetrachloroethane, 1,1,1-trichloroethane, o-dichlorobenzene, and m-dichlorobenzene; aromatic hydrocarbons such as toluene, benzene, and xylene; N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), 1,4-dioxane, and tetrahydrofuran.
Examples of the crosslinking agent include aliphatic polyfunctional epoxy compounds such as 1,5-hexadiene di-epoxy and 1,4-butanediol diglycidyl ether; aromatic polyfunctional epoxy compounds such as 2,2-bis(4-glycidyloxyphenyl)propane and N,N-diglycidyl-4-glycidyloxyaniline; and heterocycle-containing polyfunctional epoxy compounds such as triglycidyl isocyanurate.
Examples of the curing agent include imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole; tertiary amines such as 4-dimethylaminopyridine, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol; and organic phosphines such as triphenylphosphine and tributylphosphine.
The laminate can be suitably used for a high-frequency circuit board, and it is preferable to use the laminate as a laminate for a high-frequency circuit board.
Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited thereto. In structural formulae shown below, Me represents a methyl group.
A specific polyarylate P-01 was prepared according to the following scheme.
2,2-bis(4-hydroxyphenyl)-4-methylpentane (manufactured by Honshu Chemical Industry Co., Ltd.; 11.4493 g), 2,3,5-trimethylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.; 0.1750 g), sodium hydrosulfite (manufactured by FUJIFILM Wako Pure Chemical Corporation; 0.0572 g), and water (230 mL) were charged into a reaction container equipped with a stirrer to obtain a suspension. Sodium hydroxide (manufactured by FUJIFILM Wako Pure Chemical Corporation; 4.8378 g), benzyltributylammonium chloride (manufactured by FUJIFILM Wako Pure Chemical Corporation; 0.1981 g), and water (150 mL) were added to the suspension with stirring at a temperature of room temperature (20° C.), and the mixture was stirred for 30 minutes under a nitrogen atmosphere to obtain a solution in which the solids were mostly dissolved (there was some turbidity). o-dichlorobenzene (manufactured by FUJIFILM Wako Pure Chemical Corporation; 210 mL) was added to the aqueous solution, the mixture was stirred for 30 minutes under a nitrogen atmosphere, and then 4,4′-biphenyldicarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.; 12.0000 g) as powder was added thereto. After completion of the addition, the temperature was set to room temperature (20° C.), and the mixture was stirred for 4 hours under a nitrogen atmosphere to proceed a reaction. The solution after the polymerization was diluted with o-dichlorobenzene (300 mL), and the water phase was removed. After washing with a dilute acetic acid solution and ion exchange water, the resultant was poured into methanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) to precipitate a polymer. The precipitated polymer was filtered, and dried at 50° C. The polymer was re-dissolved in 900 mL of tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation), and poured into methanol to precipitate the polymer. The precipitated polymer was filtered, washed with methanol, and then dried at 50° C. to obtain a white specific polyarylate P-01 (17.8 g). A weight-average molecular weight (Mw) of the specific polyarylate P-01, which was determined as a polystyrene-equivalent molecular weight by gel permeation chromatography (GPC; using tetrahydrofuran as an eluent), was 120,000.
A specific polyarylate P-02 was prepared according to the following scheme.
4,4′-(2-ethylhexylidene)diphenol (manufactured by Honshu Chemical Industry Co., Ltd.; 11.3740 g), 4,4′-decylidenebisphenol (manufactured by Honshu Chemical Industry Co., Ltd.; 1.3826 g), 2,3,5-trimethylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.; 0.1757 g), sodium hydrosulfite (manufactured by FUJIFILM Wako Pure Chemical Corporation; 0.0515 g), and water (240 mL) were charged into a reaction container equipped with a stirrer to obtain a suspension. Sodium hydroxide (manufactured by FUJIFILM Wako Pure Chemical Corporation; 4.8323 g), benzyltributylammonium chloride (manufactured by FUJIFILM Wako Pure Chemical Corporation; 0.1783 g), and water (160 mL) were added to the suspension with stirring at a temperature of room temperature (20° C.), and the mixture was stirred for 30 minutes under a nitrogen atmosphere to obtain a solution in which the solid contents were mostly dissolved (there was some turbidity). o-dichlorobenzene (manufactured by FUJIFILM Wako Pure Chemical Corporation; 220 mL) was added to the aqueous solution, the mixture was stirred for 30 minutes under a nitrogen atmosphere, and then 4,4′-biphenyldicarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.; 12.0000 g) as powder was added thereto. After completion of the addition, the temperature was set to room temperature (20° C.), and the mixture was stirred for 4 hours under a nitrogen atmosphere to proceed a reaction. The solution after the polymerization was diluted with o-dichlorobenzene (300 mL), and the water phase was removed. After washing with a dilute acetic acid solution and ion exchange water, the resultant was poured into methanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) to precipitate a polymer. The precipitated polymer was filtered, and dried at 50° C. The polymer was re-dissolved in 900 mL of tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation), and poured into methanol to precipitate the polymer. The precipitated polymer was filtered, washed with methanol, and then dried at 50° C. to obtain a white specific polyarylate P-02 (17.5 g). A weight-average molecular weight (Mw) of the specific polyarylate P-02, which was determined as a polystyrene-equivalent molecular weight by gel permeation chromatography (GPC; using tetrahydrofuran as an eluent), was 130,000.
A specific polyarylate P-03 was prepared according to the following scheme.
2,2-bis(4-hydroxyphenyl)-4-methylpentane (manufactured by Honshu Chemical Industry Co., Ltd.; 6.8697 g), 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (manufactured by Tokyo Chemical Industry Co., Ltd.; 6.4109 g), 2,3,5-trimethylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.; 0.1757 g), sodium hydrosulfite (manufactured by FUJIFILM Wako Pure Chemical Corporation; 0.0343 g), and water (244 mL) were charged into a reaction container equipped with a stirrer to obtain a suspension. Sodium hydroxide (manufactured by FUJIFILM Wako Pure Chemical Corporation; 4.8323 g), benzyltributylammonium chloride (manufactured by FUJIFILM Wako Pure Chemical Corporation; 0.1981 g), and water (163 mL) were added to the suspension with stirring at a temperature of room temperature (20° C.), and the mixture was stirred for 30 minutes under a nitrogen atmosphere to obtain a solution in which the solids were mostly dissolved (there was some turbidity). Dichloromethane (manufactured by FUJIFILM Wako Pure Chemical Corporation; 250 mL) was added to the aqueous solution, the mixture was stirred for 30 minutes under a nitrogen atmosphere, and then 4,4′-biphenyldicarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.; 12.0000 g) as powder was added thereto. After completion of the addition, the temperature was set to room temperature (20° C.), and the mixture was stirred for 4 hours under a nitrogen atmosphere to proceed a reaction. The solution after the polymerization was diluted with dichloromethane (300 mL), and the water phase was removed. After washing with a dilute acetic acid solution and ion exchange water, the resultant was poured into methanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) to precipitate a polymer. The precipitated polymer was filtered, and dried at 50° C. The polymer was re-dissolved in 900 mL of tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation), and poured into methanol to precipitate the polymer. The precipitated polymer was filtered, washed with methanol, and then dried at 50° C. to obtain a white specific polyarylate P-03 (20.1 g). A weight-average molecular weight (Mw) of the specific polyarylate P-03, which was determined as a polystyrene-equivalent molecular weight by gel permeation chromatography (GPC; using tetrahydrofuran as an eluent), was 90,000.
As shown in the following table, predetermined amounts of various components were mixed to obtain each composition for forming a polymer layer.
The LCP (liquid crystal polymer particles; 84.9 parts by mass), Novatec LD (low density polyethylene; 12.0 parts by mass) manufactured by Japan Polyethylene Corporation, Bond First (registered trademark) E (copolymer of ethylene and glycidyl methacrylate (E-GMA copolymer); 3.0 parts by mass) manufactured by Sumitomo Chemical Co., Ltd., and Irganox 1010 (hindered phenol-based thermal stabilizer; 0.1 parts by mass) manufactured by BASF SE were mixed with each other, and pelletized by kneading using an extruder. The polymer pelletized by kneading was dried at 80° C. using a dehumidifying hot air dryer having a dew point temperature of −45° C. for 12 hours to reduce the moisture content to 50 ppm or less.
A composition for forming a polymer layer, which was used for forming a first layer shown in Table 2, was applied onto a treated surface of a copper foil (manufactured by FUKUDA METAL FOIL & POWDER CO., LTD., CF-T4X-SV-18, thickness: 18 μm, surface roughness Rz of treated surface: 0.85 μm) while adjusting the flow rate so that the film thickness after drying was obtained as shown in Table 2. The coating film was dried under the conditions of 80° C. and 2 hours to obtain a laminate B including a polymer layer B corresponding to the first layer shown in Table 2 on the copper foil.
A composition for forming a polymer layer, which was used for forming a first layer shown in Table 2, was applied onto a treated surface of a copper foil (manufactured by FUKUDA METAL FOIL & POWDER CO., LTD., CF-T4X-SV-18, thickness: 18 μm, surface roughness Rz of treated surface: 0.85 μm) while adjusting the flow rate so that the film thickness after drying was obtained as shown in Table 2. The coating film was dried under the conditions of 80° C. and 2 hours to obtain a laminate including a polymer layer C1 corresponding to the first layer shown in Table 2 on the copper foil.
The copper foil in the laminates of Examples and Comparative Examples was removed by an etching treatment (immersed in a 40% by mass aqueous solution of iron (III) chloride (manufactured by Wako Pure Chemical Industries, Ltd.) for 6 hours), and then a sample for measuring dielectric characteristics and measuring water absorption rate was obtained.
Dielectric characteristics were evaluated by measuring a dielectric loss tangent using a resonance perturbation method at a frequency of 10 GHz.
The measurement sample (approximately 0.2 g) was cut out and infused with deionized water. After the infusing at 25° C. for 1 week, water droplets on the surface were wiped off, and a water absorption rate was measured by Karl Fischer vaporization method (measurement device: AQ-2250, vaporization device: AQS-225320, used reagent: AQUALITE RS-A (for general use), measurement temperature: 180° C., nitrogen gas flow rate: 200 mL/min) and evaluated according to the following evaluation standard.
Each of the laminates of Examples and Comparative Examples was cut into a strip shape of 1 cm×5 cm to produce a sample for evaluating adhesiveness. Adhesiveness (unit: kN/m) of the obtained evaluation sample was measured according to a method for measuring a peeling strength described in JIS C 6481. The peeling conditions were such that the copper foil was peeled off from the evaluation sample at a peeling rate of 50 mm/sec at an angle of 90° with respect to the evaluation sample. The measurement was carried out 5 times, and an arithmetic average value was obtained and evaluated according to the following evaluation standard.
The evaluation results are shown in Table 2.
From the results shown in the table, it was found that the laminate according to the embodiment of the present invention was excellent in all of low dielectric characteristics, low water absorption rate, and adhesiveness.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-157310 | Sep 2022 | JP | national |
This application is a Continuation of PCT International Application No. PCT/JP2023/033752 filed on Sep. 15, 2023, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2022-157310 filed on Sep. 30, 2022. The above applications are hereby expressly incorporated by reference, in their entirety, into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2023/033752 | Sep 2023 | WO |
| Child | 19055504 | US |
