Resin films, circuit board materials, circuit boards, and electronic devices

Abstract

To provide a resin film that allows further reduction of dielectric loss tangents (lower dielectric loss tangents) and further reduction of deformation due to temperature change (lower linear expansion coefficients), and also has excellent water resistance.SOLUTION: A resin film comprises a resin composition comprising a polyaryl ketone resin (A), a polyether imide resin (B), and a fluorinated filler (C). In the film, the fluorinated filler (C) has an aspect ratio of 2 or more to 20 or less, with its content of 25 pts. mass or more relative to the total content of 100 pts. mass of the polyaryl ketone resin (A) and the polyether imide resin (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin film suitable for use as, for example, a circuit board material, a circuit board material using the resin film, a circuit board, and an electronic device. [Background technology]

[0002] Insulating materials for printed circuit boards require solder heat resistance due to their manufacturing process. For example, if heat-resistant thermoplastic resins such as polyetherketone resin or polyimide resin can be used as insulating materials for printed circuit boards, they can exhibit excellent electrical properties at high temperatures, and it is expected that the reliability of circuits in high-temperature environments can be improved. However, these heat-resistant thermoplastic resins have high molding temperatures, which necessitates the use of adhesives such as epoxy resins or hot press molding at temperatures above 260°C when bonding them to conductors, resulting in problems such as the time required for heating and cooling. Furthermore, in the case of crystalline resins, adhesion cannot be obtained unless heated to near the melting point, and above the melting point, the resin suddenly flows out, causing deformation due to fluidity.

[0003] Therefore, Patent Document 1 discloses a film-like insulator comprising 65 to 35% by mass of crystalline polyarylketone resin and 35 to 65% by mass of amorphous polyetherimide resin, having a glass transition temperature of 150 to 230°C and a crystal melting peak temperature of 260°C or higher.

[0004] Furthermore, in order to support high frequencies for next-generation high-speed communication (5G), there is a demand for lower dielectric constant and lower dielectric loss tangent of substrate materials.

[0005] Therefore, in order to enable high-frequency operation, for example, Patent Document 2 discloses a multilayer polyimide film as a substrate material containing polytetrafluoroethylene (PTFE) micropowder in polyimide. Patent Document 3 discloses an electromagnetic shielding film having an insulating resin layer and a conductive layer containing a metal adjacent to the insulating resin layer, wherein the insulating resin layer contains a polyimide having a specific structure.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] As described above, if a resin film formed from a resin composition containing a crystalline polyarylene ketone resin and an amorphous polyetherimide resin can be used as a material for a printed wiring board, it is expected to have excellent electrical properties at high temperatures and to obtain circuit reliability. However, considering high-frequency compatibility for next-generation high-speed communication (5G), it was necessary to further reduce the dielectric tangent. In addition, it was also necessary to solve the problem of water absorption, which is an inherent problem of polyimide resins. Furthermore, assuming use in a printed wiring board, due to the mismatch between thermal and cold changes, there is a possibility of causing peeling of the copper foil. Therefore, it was also necessary to lower the linear expansion coefficient of the resin film and make it as close as possible to the linear expansion coefficient of copper.

[0008] Therefore, the present invention relates to a resin film formed from a resin composition containing a polyarylene ketone resin and a polyetherimide resin, and aims to provide a resin film that can have a lower dielectric tangent (lower dielectric tangent), a smaller shape change due to temperature change (lower linear expansion coefficient), and excellent water resistance (low water absorption). [Means for solving the problem]

[0009] According to the present invention, the following resin film and circuit board material using the resin film are provided. [1] A resin film comprising a resin composition containing a polyarylketone resin (A), a polyetherimide resin (B), and a fluorine-containing filler (C), A resin film in which the aspect ratio of the fluorine-containing filler (C) in the film is 2 or more and 20 or less, and its content is 25 parts by mass or more per 100 parts by mass of the total content of polyarylketone resin (A) and polyetherimide resin (B). [2] The resin film according to [1], comprising 20 to 70 parts by mass of polyarylketone resin (A) and 20 to 70 parts by mass of polyetherimide resin (B) per 100 parts by mass of the resin composition. [3] The resin film according to [1] or [2], wherein the fluorine-containing filler (C) has an average particle size of 5 μm or less in a thickness cross section in the film width direction, with the long axis of the filler as the particle size. [4] The fluorine-containing filler (C) has a bulk density of 0.1 g / cm³ 3 More than 1.0g / cm 3 A resin film as described in any of the following [1] to [3]. [5] The resin film according to any one of [1] to [4], wherein the fluorine-containing filler (C) is synthetic mica. [6] A resin film according to any of [1] to [5], wherein the relative crystallinity is 90% or less. [7] A resin film according to any of [1] to [6], wherein the dielectric loss tangent at 10 GHz is 0.005 or less. [8] A resin film according to any of [1] to [7], wherein the relative permittivity at 10 GHz is 3.8 or less. [9] A resin film according to any of [1] to [8], wherein the coefficient of linear expansion is 50 ppm / °C or less.

[10] A resin film used on a circuit board, as described in any of [1] to [9].

[0010]

[11] A circuit board material having a structure in which a resin film described in any of [1] to [9] is laminated with a conductor.

[0011]

[12] A circuit board comprising the circuit board material described in

[11] .

[13]

[12] An electronic device having the circuit board described above. [Effects of the Invention]

[0012] The resin film proposed in this invention is a resin film made of a resin composition containing a polyarylketone resin and a polyetherimide resin, to which a specific amount of a fluorine-containing filler (C) of a specific shape is blended. With such a resin film, the dielectric loss tangent can be made lower (low dielectric loss tangent), the change in shape due to temperature changes can be made smaller (low coefficient of linear expansion), and the water absorption rate can be low and the water resistance can be excellent. Furthermore, by using a fluorine-containing filler (C) with an aspect ratio of 20 or less, it is possible to prevent defects such as holes from occurring during film formation. Moreover, because the filler has good dispersibility, it is possible to increase the filler density while maintaining film-forming properties and mechanical properties, thereby further improving the reduction of dielectric loss tangent and the coefficient of thermal expansion. [Modes for carrying out the invention]

[0013] Next, the present invention will be described based on examples of embodiments. However, the present invention is not limited to the embodiments described below.

[0014] <This resin film> An example of an embodiment of the present invention (referred to as "the resin film") is a resin film comprising a resin composition (referred to as "the resin composition") that includes at least a polyarylketone resin (A), a polyetherimide resin (B), and a fluorine-containing filler (C).

[0015] By incorporating a fluorine-containing filler (C) into a mixture of polyarylketone resin (A) and polyetherimide resin (B), it is possible not only to reduce the dielectric loss tangent but also to lower the coefficient of thermal expansion when the film is formed, bringing it closer to that of copper, for example. Furthermore, it is possible to resolve the water absorption problem that is a challenge for polyimide films.

[0016] <Polyaryl ketone resin (A)> Polyaryl ketone resins are typically crystalline resins with excellent heat resistance, flame retardancy, hydrolysis resistance, and chemical resistance. Their glass transition temperature is preferably between 140°C and 170°C. Furthermore, the crystalline nature of polyarylketone resin can be determined by differential scanning calorimetry (DSC), specifically by confirming at least one of the crystal melting peak and / or recrystallization peak.

[0017] Polyarylketone resins (A) are thermoplastic resins whose structural units include aromatic rings, ether bonds, and ketone bonds. Typical examples include polyetherketone, polyetheretherketone, polyetherketoneketone, and polyetheretherketoneketone. In particular, polyether ether ketone is preferred for this resin composition. Furthermore, the polyarylketone resin used may be one type alone, or two or more types may be used in combination.

[0018] The crystal melting temperature of the polyarylketone resin (A) is preferably 260 to 400°C. In particular, when this resin film is applied as a substrate for electronics substrates such as printed circuit boards, the crystal melting peak temperature of the polyarylketone resin (A) is preferably 260°C or higher, more preferably 280°C or higher, and even more preferably 300°C or higher.

[0019] <Polyetherimide resin (B)> The polyetherimide resin (B) is not particularly limited, and its production method and properties are described in, for example, U.S. Patent 3,905,942 and U.S. Patent 3,803,085.

[0020] The polyetherimide resin (B) used in this resin composition is usually an amorphous resin, and specifically, it preferably has a repeating unit represented by the following general formula (1). It is preferable that the polyetherimide resin (B) has the following repeating unit structure in that it is easy to improve various performances. Note that the fact that the polyetherimide resin is amorphous can be determined by DSC.

[0021] TIFF0007852374000001.tif47170

[0022] In general formula (1), Y 1 ~Y 6 each independently represents a hydrogen atom, an alkyl group, or an alkoxy group, and Ar 7 ~Ar 9 each independently represents an arylene group having 6 to 24 carbon atoms which may have a substituent, and X 1 represents either a direct bond, or -O-, -SO2-, -S-, -C(=O)-, or a divalent aliphatic hydrocarbon group.

[0023] The polyetherimide resin (B) preferably has a structure in which the repeating unit represented by the above general formula (1) is repeated, for example, 10 to 1,000 times. The number of repeating units is more preferably 20 to 700, and even more preferably 30 or more or 500 or less. If the number of repeating units is within such a range, the viscosity at the time of melting is not too high, the moldability is excellent, and various performances such as heat resistance and heat aging resistance tend to be well balanced and easy to improve.

[0024] Y 1 ~Y 6The alkyl group in this is, for example, an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 2 carbon atoms. Specifically, preferred examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, 1-methylpentyl group, n-hexyl group, isohexyl group, and the like. Also, Y 1 ~Y 6 The alkoxy group in this is, for example, an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 2 carbon atoms. Specifically, preferred groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentyloxy, and n-hexyloxy groups. Y 1 ~Y 6 They may be the same or they may be different. 1 ~Y 6 It is preferable that it be a hydrogen atom.

[0025] Ar 7 ~Ar 9 Examples of arylene groups in this context include phenylene groups, naphthylene groups, and anthracenylene groups. Examples of substituents on the arylene group include alkyl groups, halogens, alkoxy groups, and halogen-substituted alkyl groups. The alkyl and alkoxy groups used as substituents have, for example, 1 to 6 carbon atoms, preferably 1 to 2 carbon atoms, and specific examples are as described above. A halogen-substituted alkyl group is a group in which one or more hydrogen atoms of an alkyl group are substituted with halogens. The alkyl group in a halogen-substituted alkyl group is the same as described above. Examples of halogens include chlorine atoms, bromine atoms, fluorine atoms, and iodine atoms. 7 ~Ar 9They may be the same or different from each other. 7 ~Ar 9 If substituents are present, the number of carbon atoms in the arylene group should preferably be between 6 and 24. Ar 7 ~Ar 9 The phenylene group is preferably a phenylene group which may have substituents, and among these, the phenylene group is preferred.

[0026] X 1 The divalent aliphatic hydrocarbon group in is preferably a divalent aliphatic hydrocarbon group having 1 to 6 carbon atoms, and more preferably a divalent saturated aliphatic hydrocarbon group. Divalent saturated aliphatic hydrocarbon groups are -C y H 2y It is represented as -(y is an integer from 1 to 6), and specific examples include the methylene group, dimethylene group, trimethylene group, propylene group, ethylidene group (-CH(CH3)-), and dimethylmethylene group (-C(CH3)2-). X 1 A divalent saturated aliphatic hydrocarbon group is preferred, and a dimethylmethylene group (-C(CH3)2-) is more preferred.

[0027] In the above general formula (1), Ar 9 This may be a 1,4- or 1,3-arylene group having 6 to 24 carbon atoms, which may have substituents, but is preferably a 1,4-arylene group having 6 to 24 carbon atoms, which may have substituents. The bond position with the imide group is at the 1,4 position, which makes the structure stable and improves heat aging resistance, and also tends to achieve excellent low water absorption, heat resistance, and impact resistance such as puncture impact strength. Therefore, the polyetherimide resin (B) is preferably represented by the following general formula (2).

[0028] TIFF0007852374000002.tif43170

[0029] In general formula (2), Y 1 ~Y 6Each of these independently represents a hydrogen atom, an alkyl group, or an alkoxy group, and Ar 7 ~Ar 9 Each of these independently represents an arylene group having 6 to 24 carbon atoms, which may have substituents, and X 1 represents either a direct bond or one of the following: -O-, -SO2-, -S-, -C(=O)-, or a divalent aliphatic hydrocarbon group. (1,4)Ar in general formula (2) 9 The imide group is Ar 9 It is connected to the 1st and 4th positions of the base.

[0030] Y in general formula (2) 1 ~Y 6 , X 1 This is as explained above. Ar 9 The arylene group in is a 1,4-phenylene group, a 1,4-naphthylene group, 1, Examples include the 4-anthracenylene group. These arylene groups may have substituents as described above, but the substituents are as explained above. 9 This is preferably a 1,4-phenylene group which may have a substituent, and more preferably a 1,4-phenylene group.

[0031] In general formula (2), Ar 7 Ar 8 As explained above, Ar 7 and Ar 8 It is preferably a 1,4-arylene group having 6 to 24 carbon atoms, which may have substituents. Examples of 1,4-arylene groups include 1,4-phenylene group, 1,4-naphthylene group, and 1,4-anthracenylene group. These arylene groups may have substituents as described above, but the substituents are as explained above. Ar 7 and Ar 8 It is more preferably a substituted 1,4-phenylene group, and even more preferably a substituted 1,4-phenylene group.

[0032] In particular, the polyetherimide resin (B) used in this resin composition is especially preferred to have a structure represented by the following formula (3). The polyetherimide resin (B) has the following structure, which tends to result in this resin film having excellent mechanical properties, good crystallinity, heat resistance, and good adhesion to metals, etc. Furthermore, it tends to have good moldability and secondary processing properties.

[0033] TIFF0007852374000003.tif39170

[0034] In the general formula (3) above, n (number of repetitions) is usually an integer in the range of 10 to 1,000, preferably 20 or more or 700 or less, and more preferably 30 or more or 500 or less. When n is within this range, the viscosity at melting is not too high, resulting in excellent moldability and a good balance of various properties such as heat resistance and heat aging resistance.

[0035] A specific example of the polyetherimide resin (B) having the above structure is, for example, one sold by Savic Innovative Plastics under the product name "Ultem" series.

[0036] Furthermore, it is particularly preferable to use a combination of two types of polyetherimide resin (B): a polyetherimide resin having the structure shown in structural formula (4) below and a polyetherimide resin having the structure shown in structural formula (5) below, from the viewpoint of adjusting the crystallization rate, adjusting the relative degree of crystallinity, and improving mechanical properties. Here, the polyetherimide resin having the structure shown in structural formula (4) is a polycondensate of 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic acid dianhydride and p-phenylenediamine (para-polyetherimide), and is known to be partially compatible with polyarylketone resin (A), such as PEEK, and can improve the mechanical properties of this resin film. On the other hand, the polyetherimide resin having the structure shown in the above structural formula (5) is a polycondensate of 4,4'-[isopropylidenebis(p-phenyleneoxy)]diphthalic acid dianhydride and m-phenylenediamine (meta-polyetherimide), and is known to be compatible with polyarylketone resin (A), such as PEEK, and the crystallization rate of this resin composition can be adjusted.

[0037] The preferred blending ratio of the two is 1 to 80 parts by mass of the polyetherimide resin having the structure shown in structural formula (4) per 100 parts by mass of the total of both, and more preferably 10 parts by mass or more, or 70 parts by mass or less, and more preferably 20 parts by mass or more, or 60 parts by mass or less.

[0038] TIFF0007852374000004.tif64170

[0039] Furthermore, other copolymerizable monomer units may be introduced into each of the polyetherimide resins described above, as long as they do not exceed the spirit of the present invention. Furthermore, polyetherimide resins can be used individually or in combination of two or more types.

[0040] The glass transition temperature of the polyetherimide resin (B) is preferably 160°C or higher and 300°C or lower, more preferably 170°C or higher or 290°C or lower, more preferably 180°C or higher or 280°C or lower, more preferably 190°C or higher or 270°C or lower, and most preferably 200°C or higher or 260°C or lower. If the glass transition temperature of polyetherimide resin (B) is above the lower limit, the heat resistance of this resin composition tends to be sufficient. On the other hand, if the glass transition temperature of polyetherimide resin (B) is below the upper limit, molding or secondary processing can be performed at relatively low temperatures. Furthermore, if the mixture contains two or more types of polyetherimide resin (B), it is preferable that the glass transition temperatures of each resin fall within the above range.

[0041] <Fluorine-containing filler (C)> There are no particular limitations on the fluorine-containing filler; it may be an organic filler or an inorganic filler. The shape of the filler can include, for example, fibrous, flaky, plate-like, or thin flake-like shapes. Examples of the inorganic fillers include, for example, flake-like, plate-like, or flaky powders made of inorganic materials such as clay, glass, silica, aluminum nitride, silicon nitride, synthetic mica, natural mica, boehmite, talc, sericite, illite, kaolinite, montmorillonite, vermiculite, smectite, alumina, titanates such as magnesium potassium titanate and lithium potassium titanate, and calcium carbonate. Other examples include glass fibers, aramid fibers, carbon fibers, and potassium titanate fibers. Among these, the fluorine-containing filler (C) is preferably a particle of silica, glass, mica, talc, kaolin, calcium carbonate, etc., that contains fluorine. Among these, mica particles containing fluorine are preferred because they can improve dielectric properties.

[0042] Mica (also called mica) is a plate-like crystalline mineral belonging to the mica group of phyllosilicate minerals. It is classified into two types: natural mica (muscovite, biotite, phlogopite, etc.) and synthetic mica that is artificially produced. In particular, synthetic mica is known in which the hydroxyl groups (OH) of naturally occurring mica are replaced with fluorine (F) to enable use at high temperatures. Well-known methods for synthesizing synthetic mica include hydrothermal synthesis, solid-phase synthesis, and melt synthesis, and it may be manufactured by any of these methods. Among synthetic mica particles, non-swelling synthetic mica is particularly preferred from the viewpoint of heating dimensional stability and water resistance. Examples of non-swelling synthetic micas include fluorinated phlogopite, potassium tetrasilicate, and potassium teniolite.

[0043] (Aspect ratio) The aspect ratio of the fluorine-containing filler (C) in the film is preferably between 2 and 20. Such a low aspect ratio fluorine-containing filler (C) is preferable because it not only prevents defects such as pore formation, but also has good dispersion properties and is less prone to aggregation, allowing for high-density filling of the film while maintaining film-forming properties and mechanical characteristics, thereby reducing the coefficient of thermal expansion of the film. From this viewpoint, the aspect ratio of the fluorine-containing filler (C) in the film is more preferably 2.2 or more or 18 or less, even more preferably 2.5 or more or 15 or less, particularly more preferably 2.7 or more or 13 or less, and most preferably 3 or more or 10 or less.

[0044] The aspect ratio (= major axis diameter / minor axis diameter) of the filler material (C) in the film can be obtained by observing the filler material in the film cross-section in the film width direction (TD, direction perpendicular to the flow direction) using an electron microscope, determining the major axis diameter (maximum diameter) and minor axis diameter (diameter perpendicular to the maximum diameter) of each filler material, and then calculating it. In this process, at least 100 or more filler materials are arbitrarily selected, the aspect ratio of each filler material is calculated, and the average of these is taken as the average aspect ratio. Furthermore, if the filler material exhibits a flaky appearance, the average value of the particle size when the diameter of each filler material, i.e., the long axis, is considered the particle size, is divided by the average value of the thickness of each filler material.

[0045] (particle size) From the viewpoint of film-forming properties, the average particle size of the filler (C) in the film is preferably 5 μm or less, more preferably 4 μm or less, more preferably 3 μm or less, and especially preferably 2 μm or less. On the other hand, from the viewpoint of the filler's filling effect, the average particle size of the filler (C) in the film is preferably 0.1 μm or larger, and more preferably 0.3 μm or larger. The particle size of the filler (C) in the film is the average particle size obtained by observing the thickness cross-section in the width direction and using the long axis (maximum diameter) of each filler as the particle size. In this case, at least 100 or more fillers are randomly selected from the film cross-section in the film width direction (TD, direction perpendicular to the flow direction), the long axis of each filler is measured, and the average of these measurements is taken as the average particle size.

[0046] (Bulk density) Fluorine-containing filler (C) has a bulk density of 0.1 g / cm³, from the viewpoint of ease of filling into resin. 3 Preferably, it is 0.13 g / cm³ or more. 3 In particular, 0.15 g / cm³ 3 It is even more preferable if the above conditions are met. On the other hand, from the viewpoint of improving the surface area of ​​the filler, 1.0 g / cm 3 Preferably, it is 0.8 g / cm³ 3 Among them, 0.5 g / cm³ 3 The following is even more preferable:

[0047] (Other ingredients) In addition to the components described above, this resin composition may optionally contain other resins, fillers, and various additives, such as heat stabilizers, ultraviolet absorbers, light stabilizers, nucleating agents, colorants, lubricants, and flame retardants. The content of other resins is not particularly limited, but it may be, for example, about 10 parts by mass or less per 100 parts by mass of the total amount of polyarylketone resin (A) and polyetherimide resin (B). However, it is preferable that the resin in this resin composition consists of polyarylketone resin (A) and polyetherimide resin (B).

[0048] <Percentage of each ingredient> When this resin composition is used as a substrate for electronics substrates such as printed circuit boards, it is preferable that the resin composition contains polyarylketone resin (A) and polyetherimide resin (B) in a mixed mass ratio of A / B = 70 to 30 / 30 to 70. In particular, for the following reasons, it is preferable that the resin composition contains a crystalline polyarylketone resin (A) and an amorphous polyetherimide resin (B). In a mixed resin of polyarylketone resin (A) and polyetherimide resin (B), as the content of polyetherimide resin (B) increases, the glass transition temperature of the mixed resin improves, and the crystallization temperature (Tc) measured by DSC during heating shifts to a higher temperature, reducing the crystallization rate. Here, if the polyetherimide resin (B) is 30% by mass or more, the glass transition temperature of the entire resin composition can be improved, preventing insufficient heat resistance, preventing large volume shrinkage (dimensional change) due to crystallization, and maintaining reliability as a circuit board, which is preferable. Also, because the crystallization rate does not increase, it is possible to prevent crystallization before adhesion to a substrate such as copper foil when laminating the resin film onto the substrate using a heating roller or the like. In other words, by increasing the content of polyetherimide resin (B) to a certain extent, the crystallization rate can be reduced, and by heating above Tg, the elastic modulus can be reduced to the rubbery elastic range, allowing lamination onto substrates such as copper foil in a relatively low temperature range. On the other hand, if the content of polyetherimide resin (B) is 70% by mass or less, it is preferable because it prevents the overall crystallinity of the composition from becoming too low, and the crystallization rate does not become too slow. Furthermore, since the dielectric loss tangent of polyetherimide resin is higher than that of polyarylketone resin, it is also preferable from the viewpoint of reducing the dielectric loss tangent of the resin composition that the content of polyetherimide resin (B) be 70% by mass or less. From this perspective, the mass ratio of polyarylketone resin (A) to polyetherimide resin (B) is preferably 70:30 to 30:70, as described above, and more preferably 65:35 to 35:65, and even more preferably 60:40 to 40:60.

[0049] From the viewpoint of imparting heat resistance through crystallization, the content of polyarylketone resin (A) is preferably 20 parts by mass or more per 100 parts by mass of the resin composition, and more preferably 25 parts by mass or more. On the other hand, from the viewpoint of adhesion to copper foil, the content is preferably 70 parts by mass or less per 100 parts by mass of the resin composition, and more preferably 60 parts by mass or less, and more preferably 50 parts by mass or less.

[0050] From the viewpoint of adjusting the crystallization rate of the resin composition, the content of polyetherimide resin (B) is preferably 20 parts by mass or more, 30 parts by mass or more, and more preferably 40 parts by mass or more, per 100 parts by mass of the resin composition. On the other hand, from the viewpoint of reducing dielectric loss tangent, it is preferably 70 parts by mass or less, 60 parts by mass or less, and more preferably 50 parts by mass or less, per 100 parts by mass of the resin composition.

[0051] From the viewpoint of reducing dielectric loss tangent and reducing the coefficient of linear expansion, the content of the fluorine-containing filler (C) is preferably 25 parts by mass or more per 100 parts by mass of the total content of the polyarylketone resin (A) and polyetherimide resin (B), and more preferably 30 parts by mass or more. On the other hand, from the viewpoint of film-forming properties, the content is preferably 50 parts by mass or less per 100 parts by mass of the total content of the polyarylketone resin (A) and polyetherimide resin (B), and more preferably 40 parts by mass or less.

[0052] (Film thickness) When used as a circuit board material for electrical and electronic equipment, the thickness of this resin film is preferably 10 μm or more or 300 μm or less, more preferably 20 μm or more or 200 μm or less, and more preferably 30 μm or more or 100 μm or less. Furthermore, it is preferable to manufacture the film in such a way that the anisotropy of its physical properties in the flow direction (MD) and its perpendicular direction (TD) is minimized.

[0053] (Dielectric loss tangent) The dielectric loss tangent is an indicator of electrical energy loss within an insulator, and is a value determined from the ratio of the current being charged to the current being lost. In an ideal insulator, there is no electrical energy loss, so a small dielectric loss tangent is desirable for an insulator. In high-frequency substrates, power absorption per unit volume causes signal transmission loss, which is converted into heat. The dielectric loss tangent affects the quality of signal transmission; therefore, the larger the dielectric loss tangent, the greater the absorption and signal loss, and conversely, the lower the dielectric loss tangent, the less signal loss there is. The dielectric loss tangent of this resin film at 10 GHz is preferably 0.005 or less, and more preferably 0.004 or less, from the viewpoint of high-frequency circuit board applications. A smaller dielectric loss tangent is preferable because it reduces dielectric loss, leading to improved electrical signal transmission efficiency and higher speeds in the circuit board. The lower limit of the dielectric loss tangent is not particularly limited.

[0054] (Relative permittivity) One purpose of increasing frequency is to transmit signals faster; in other words, in high-frequency circuits, it is necessary to increase the speed of signals. The lower the relative permittivity, the faster the signal speed becomes, approaching the speed of light. Therefore, a material with a low relative permittivity is appropriate. From this viewpoint, the relative permittivity of the resin film is preferably 3.8 or less, more preferably 3.6 or less, more preferably 3.4 or less, more preferably 3.2 or less, and more preferably 3.0 or less. A smaller relative permittivity is preferable because it reduces dielectric loss, leading to improved transmission efficiency and higher speed of electrical signals on the circuit board. The lower limit of the relative permittivity is not particularly limited.

[0055] The relative permittivity and dielectric loss tangent can be determined by creating a 50 μm thick film from this resin film, using that film as a test specimen, and measuring it using the cavity resonator method under the conditions of a temperature of 23°C, a humidity of 50% RH, and a frequency of 10 GHz.

[0056] (Water absorption rate) Water absorption, or water absorption rate, affects the dielectric constant and dielectric loss. This resin film has a low water absorption rate, which helps prevent delamination from the copper foil on the substrate. Furthermore, its increased migration resistance helps prevent short circuits. Therefore, the water absorption rate of this resin film is preferably 1% or less, more preferably 0.8% or less, and even more preferably 0.6% or less. The lower limit of the water absorption rate is not particularly limited. The water absorption rate can be measured by preparing a film from this resin film as shown in the examples, and then immersing the film as a test piece in water at 23°C for 24 hours, measuring the change in mass before and after immersion.

[0057] (Relative crystallinity) Relative crystallinity is a value determined from the ratio of the crystallized volume at a given time to the total volume that can be crystallized. The degree of crystallinity of crystalline polymers is a structural parameter deeply related to their general physical properties, and evaluating the degree of crystallinity can sometimes identify the causes of insufficient rigidity, cracking, whitening, etc. Methods for measuring the degree of crystallinity include density analysis, thermal analysis, NMR, and IR.

[0058] The resin film preferably has a relative crystallinity of 90% or less, more preferably 70% or less, more preferably 50% or less, more preferably 30% or less, more preferably 20% or less, more preferably 10% or less, more preferably 5% or less, and among these, even more preferably 2% or less. The lower limit of the relative crystallinity is not particularly limited.

[0059] The relative crystallinity can be obtained by using a differential scanning calorimeter (PerkinElmer, Pyris1 DSC) to heat a test specimen obtained from the film at a heating rate of 10°C / min, and calculating it using the following formula (1) from the heat quantity of the crystal melting peak (J / g) and the heat quantity of the recrystallization peak (J / g) obtained at this time. Relative crystallinity (%) = {1 - (ΔHc / ΔHm)} × 100 (1) ΔHc: Heat energy (J / g) of the recrystallization peak under a 10°C / min heating condition for the film material. ΔHm: Heat energy (J / g) at the crystal melting peak under a 10°C / min heating condition for the film.

[0060] If multiple recrystallization peaks are present, their total heat energy is calculated as ΔHc. If multiple crystallization peaks are present, their total heat energy is calculated as ΔHm. Films that do not show recrystallization peaks when measured with a differential scanning calorimeter (ΔHc = 0 J / g) can be considered crystallized films, while those that show recrystallization peaks can be considered films that have not completely crystallized. To achieve the relative crystallinity within the aforementioned range, for example, the conditions during film manufacturing can be appropriately adjusted, and the details of this will be described later.

[0061] The relative crystallinity can be adjusted by changing the mixing ratio of polyarylketone resin (A) and polyetherimide resin (B). Specifically, the relative crystallinity can be reduced by increasing the mixing ratio of polyetherimide resin (B), which is normally amorphous, to polyarylketone resin (A), which is normally crystalline. Furthermore, the relative crystallinity can also be adjusted by the cooling rate during film formation. For example, the relative crystallinity can be reduced by rapidly cooling the molten polymer of this resin composition. For instance, even if the blending ratio of polyetherimide resin (B) is 50% by mass or less, it is possible to reduce the relative crystallinity to 20% or less by rapid cooling. Furthermore, even films with low relative crystallinity can have their crystallinity increased through heat treatment.

[0062] (Coefficient of linear expansion) When this resin film is intended to be laminated onto a substrate such as copper foil, the mismatch between thermal and cold changes may cause the copper foil to peel off. Therefore, it is preferable to lower the coefficient of thermal expansion of this resin film and bring it as close as possible to the coefficient of thermal expansion of copper. From this viewpoint, it is preferable that the coefficient of linear expansion of this resin film is 50 ppm / °C or less in both the MD and TD directions, more preferably 40 ppm / °C or less, and even more preferably 35 ppm / °C or less. Since the coefficient of linear expansion of copper foil is approximately 20 ppm / °C, the lower limit is expected to be 15 ppm / °C or higher.

[0063] <Method of manufacturing this film> This resin film can be manufactured by melting and kneading the resin composition and then rapidly cooling it to form a film. In this case, examples of film formation methods include inflation molding, extrusion casting using a T-die, and calendering. Among these, extrusion casting using a T-die is preferred from the viewpoint of film formation properties and stable productivity. In extrusion casting using a T-die, the molding temperature is adjusted as appropriate depending on the flow characteristics and film-forming properties of the composition, but is generally above the melting point and below 430°C. The thickness of the molded body is not particularly limited, but is typically around 10 μm to 800 μm.

[0064] To reduce the relative crystallinity of this resin film, it is preferable to rapidly cool and form a film from the molten mixture of the above-mentioned mixed composition.

[0065] The molding temperature in the extrusion casting method using a T-die is adjusted as appropriate depending on the flow characteristics and film-forming properties of the resin composition, but is generally between 280°C and 350°C. For melt mixing, commonly used single-screw extruders, twin-screw extruders, kneaders, and mixers can be used, and are not particularly limited.

[0066] In the extrusion casting method using a T-die, the resulting film may be rapidly cooled and collected in an amorphous state, crystallized by heating with a casting roll, or collected in an amorphous state and then heat-treated to collect in a crystallized state. Generally, amorphous films have excellent durability and secondary processing properties, while crystallized films have excellent heat resistance and rigidity (stiffness). Therefore, the film in the optimal crystallized state should be used depending on the application and purpose.

[0067] One way to adjust the cooling conditions when cooling the molten resin composition to form a film is, for example, to use a cast roll as a cooler and bring the extruded molten resin into contact with the cast roll.

[0068] <This circuit board material> A circuit board material according to one embodiment of the present invention (referred to as "this circuit board material") has a structure in which the above-described resin film and a conductor are laminated together. For example, a circuit can be formed from this conductor to constitute a circuit board.

[0069] Copper foil can be given as an example of the aforementioned conductor. The copper foil can be patterned into a predetermined shape on a circuit board by etching or other means, and used to form wiring and other components. The thickness of the copper foil is preferably, for example, 1 to 80 μm, and more preferably 3 μm or more or 50 μm or less, and more preferably 5 μm or more or 30 μm or less.

[0070] The copper foil may be directly bonded to the base film without an adhesive layer, or it may be bonded via an adhesive layer. The adhesive layer is not particularly limited, but examples include polyimide-based resin adhesives, epoxy-based resin adhesives, acrylic-based resin adhesives, and phenol-based resin adhesives. Among these, epoxy-based resin adhesives are preferred.

[0071] Alternatively, the copper foil may be surface-treated with a surface treatment agent such as a silane coupling agent and then laminated to the base film via the surface treatment agent, or the copper foil may be laminated directly to the base film without the use of a surface treatment agent or adhesive layer.

[0072] This resin film preferably constitutes either a base film or a cover film. The base film serves as the substrate for the circuit board, and it is preferable that copper foil be provided on the base film. A cover film, sometimes called a coverlay film, is a film used to cover and protect copper foil and other materials placed on a base film. Cover films are used by being laminated to the copper foil surface of the base film or rigid substrate that forms the substrate of a circuit board. The cover film is generally bonded to a substrate such as a base film or rigid substrate via an adhesive layer. The adhesive used for the adhesive layer is as described above. The adhesive layer may also be omitted as appropriate, in which case the cover film may be bonded to copper foil that has been surface-treated with a surface treatment agent such as a silane coupling agent, or it may be bonded directly to the copper foil without an adhesive layer or surface treatment agent.

[0073] Furthermore, while copper foil is generally patterned and partially provided on the substrate, in areas where copper foil is not provided on the substrate, the cover film may be directly bonded to the substrate or bonded to the substrate via an adhesive layer.

[0074] <Circuit boards / electronic equipment> A circuit board according to one embodiment of the present invention is equipped with the circuit board material described above.

[0075] Examples of circuit boards include FPC (Flexible Printed Circuits) and FCCL (Flexible Cupper Clad Laminate). As described above, the present invention provides molded articles such as this resin film with a well-balanced and excellent performance in various aspects, including dielectric properties, and also exhibits low water absorption. Therefore, it satisfies the required characteristics for circuit boards and is suitable for use in such applications. In particular, the present invention is especially suitable for FPCs and FCCLs as described above.

[0076] An example of an electronic device according to an embodiment of the present invention is equipped with the circuit board described above. Examples of such electronic devices include portable electronic devices such as mobile phones, smartphones, electronic organizers, digital still cameras, and video cameras; electronic paper; televisions; DVD players; various audio equipment; car navigation systems; in-car displays such as instrument panels; calculators; printers; scanners; photocopiers; refrigerators; and washing machines.

[0077] <Explanation of terms> In this invention, the term "film" also includes "sheets," and the term "sheet" also includes "film." Furthermore, when the term "panel" is used, as in "image display panel" or "protective panel," it encompasses plates, sheets, and films.

[0078] In this invention, when "X~Y" (where X and Y are any numbers) is written, unless otherwise specified, it means "X or greater and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." Furthermore, when "X or greater" (where X is any number) is written, unless otherwise specified, it includes the meaning of "preferably greater than X," and when "Y or less" (where Y is any number) is written, unless otherwise specified, it also includes the meaning of "preferably less than Y." [Examples]

[0079] The present invention will be further explained in the following examples, but these examples do not limit the present invention in any way. Furthermore, various measurements of the raw materials described herein, the resin composition, and the film molded from the resin composition were performed as follows.

[0080] (1) Aspect ratio of the filler The aspect ratio (major axis diameter / minor axis diameter) of the filler was determined by observing the thickness cross-section in the width direction of the obtained film (sample) using an electron microscope, extracting at least 100 filler samples, measuring the major axis diameter and minor axis diameter of each filler, calculating the aspect ratio (major axis diameter / minor axis diameter), and taking the average of these values ​​as the average aspect ratio.

[0081] (2) Particle size of the filler The particle size of the filler was determined by observing the thickness cross-section in the width direction of the obtained film (sample) using an electron microscope, extracting at least 100 filler particles at random, measuring the major axis diameter of each filler particle, and taking the average of the major axis diameters as the average particle size.

[0082] (3) Bulk density of the filler 50cm 3 The bulk density of the filler was calculated by sealing the powdered filler into a container by tapping it several times and then measuring the mass after sealing.

[0083] (4) Glass transition temperature The raw material pellets were kneaded at 380°C using a Φ40mm coaxial single-screw extruder, then extruded through a T-die, and subsequently cooled on a casting roll at approximately 180°C to produce a 50 μm thick film. Dynamic viscoelasticity measurements were performed on the obtained film using a viscoelastic spectrometer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) in accordance with JIS K7244-4:1999, under the conditions of strain 0.1%, frequency 10 Hz, temperature range 20-400°C, and heating rate 3°C / min. The temperature at the peak of the obtained tensile loss coefficient (tanδ) was defined as the glass transition temperature.

[0084] (5) Crystal melting temperature The raw material pellets were subjected to a differential scanning calorimeter (DSC) Pyris1 DSC (manufactured by PerkinElmer) in accordance with JIS K7121:2012. The temperature range was 25 to 380°C and the heating rate was 10°C / min. The crystal melting temperature was determined from the peak top temperature of the DSC curve detected during the reheating process.

[0085] (6) Relative crystallinity The obtained film (sample) was heated at a heating rate of 10°C / min using a PerkinElmer differential scanning calorimeter "Pyris1 DSC". The relative crystallinity was calculated from the heat energy (J / g) of the crystal melting peak and the heat energy (J / g) of the recrystallization peak obtained at this time using the following formula. [Formula] Relative crystallinity (%) = {1 - (ΔHc / ΔHm)} × 100 ΔHc: Heat energy (J / g) of the recrystallization peak under a 10°C / min heating condition for the film. ΔHm: Heat energy (J / g) at the crystal melting peak under a 10°C / min heating condition for the film.

[0086] (7) Relative permittivity The obtained films (samples) were measured using the cavity resonator method in accordance with JIS C2565:1992, under conditions of 23°C, 50% RH humidity, and 10 GHz frequency.

[0087] (8) Dielectric loss tangent The obtained films (samples) were measured using the cavity resonator method in accordance with JIS C2565:1992, under conditions of 23°C, 50% RH humidity, and 10 GHz frequency. A dielectric loss tangent of 0.005 or less was rated as Good (○), and one exceeding 0.005 was rated as Poor (×).

[0088] (9) Coefficient of linear expansion The obtained film (sample) was cut to a size of 4 mm x 10 mm, and a tensile test was performed in the MD or TD direction in a thermomechanical analyzer (TMA) (Hitachi High-Tech Science Corporation, model: TMA / SS7100) while applying a load of 1 mN and maintaining a constant heating rate (5 °C / min) in the temperature range of 30 °C to 150 °C. The coefficient of linear expansion (CTE) was measured from the elongation of the film with respect to temperature. An average CTE of 35 ppm / ℃ or less in MD / TD was rated as Very Good (○), greater than 35 ppm / ℃ but 50 ppm / ℃ or less was rated as Good (△), and greater than 50 ppm / ℃ was rated as Poor (×).

[0089] (10) Water absorption rate From the obtained film (sample), a test piece with a diameter of 10 cm (thickness of 100 μm) was cut out and used as a measurement sample. In accordance with JIS K7209:2000, the obtained measurement sample was immersed in water at 23°C for 24 hours, and the water absorption rate (%) was measured from the change in mass before and after immersion.

[0090] (11) Copper foil adhesion One side of the obtained film (sample) has electrolytic copper foil. CF-V9S-SV-12 (12μm thick), manufactured by Fukuda Metal Industries, was stacked and hot-pressed at 240°C and 3MPa to produce a single-sided copper-clad sheet. We evaluated the copper foil as Good (○) if it was properly adhered, and as Poor (×) if it was not adhered.

[0091] [Polyaryl ketone resin (A)] (A)-1: Polyether ether ketone (crystalline resin, Daicel Evonik VESTAKEEP 3300G, crystal melting temperature (DSC measurement): 295°C, glass transition temperature (dynamic viscoelastic measurement): 154°C)

[0092] [Polyetherimide resin (B)] (B)-1: Polyetherimide (amorphous resin, meta-polyetherimide, Ultem CRS1000-1000 manufactured by Sabic, glass transition temperature (dynamic viscoelasticity measurement): 238°C) (B)-2: Polyetherimide (para-polyetherimide, Ultem CRS5001 manufactured by Sabic, glass transition temperature (dynamic viscoelastic measurement): 230°C)

[0093] [Filler (C)] (C)-1: Non-swelling synthetic mica (flattened shape, manufactured by Coop Chemical, MK-100, laser diffraction particle size distribution analyzer, particle size (D50) when the cumulative number of particles from the small particle size side reaches 50% is 5 μm, bulk density is 0.22 g / cm³) 3 (Contains fluorine atoms) (C)-2: Non-swelling synthetic mica (flattened shape, measured by Coop Chemical MK-200, laser diffraction particle size distribution analyzer, particle size (D50) at 50% cumulative number from the small particle size side is 8 μm, bulk density is 0.24 g / cm³) 3 (Contains fluorine atoms) (C)-3: Non-swelling synthetic mica (flattened shape, PDM-5L manufactured by Topy Industries, with a laser diffraction particle size distribution analyzer showing a particle size (D50) of 6 μm and bulk density of 0.22 g / cm³ when the cumulative number of particles from the smallest particle size side reaches 50%). 3 (Contains fluorine atoms) (C)-4: Natural mica (scale shape, muscovite, Repco MX-F, laser diffraction particle size distribution analyzer, particle size (D50) when the cumulative number of particles from the smallest particle size side reaches 50% is 4 μm, bulk density is 0.2 g / cm³) 3 (Contains no fluorine atoms)

[0094] (Example 1) A mixed composition of (A)-1, (B)-1, (B)-2, and (C)-1 was prepared as shown in Table 1. The mixture was kneaded at 380°C using a Φ40 mm coaxial single-screw extruder equipped with a T-die, then extruded from the T-die, and subsequently cooled on a casting roll at approximately 180°C to produce a 50 μm thick film (sample). The aspect ratio of filler (C)-1 in the film was 4.4, and the average particle size was 1.1 μm.

[0095] (Examples 2-3) A film (sample) was prepared in the same manner as in Example 1, except that the mixed mass ratios of (A)-1, (B)-1, (B)-2, and (C)-1 were changed as shown in Table 1. In all films (samples), the aspect ratio of the filler (C)-1 in the film was 4.4, and the average particle size was 1.1 μm.

[0096] (Example 4) A film (sample) was prepared in the same manner as in Example 1, except that the mixed mass ratios of (A)-1, (B)-1, (B)-2, and (C)-2 were changed as shown in Table 1. The aspect ratio of filler (C)-2 in the film was 6.8, and the average particle size was 1.3 μm.

[0097] (Examples 5-7) A film (sample) was prepared in the same manner as in Example 1, except that the mixed mass ratios of (A)-1, (B)-1, (B)-2, and (C)-3 were changed as shown in Table 1. The aspect ratio of filler (C)-3 in the film was 8.9, and the average particle size was 1.1 μm.

[0098] (Comparative Examples 1-4) A film (sample) was prepared in the same manner as in Example 1, except that the mixed mass ratios of (A)-1, (B)-1, (B)-2, and (C)-1 were changed as shown in Table 1. With the exception of Comparative Example 2, the aspect ratio of the filler (C)-1 in the film was 4.4 and the average particle size was 1.1 μm in all films (samples).

[0099] (Comparative Example 5) A film (sample) was prepared in the same manner as in Example 1, except that the mixed mass ratios of (A)-1, (B)-1, (B)-2, and (C)-4 were changed as shown in Table 1. The aspect ratio of filler (C)-4 in the film was 2.5, and the average particle size was 0.7 μm.

[0100] [Table 1]

[0101] The results from Examples 1-7 in Table 1 above demonstrate that incorporating fluorine-containing synthetic mica can achieve both low dielectric loss tangent and low linear expansion. Furthermore, it exhibited low water absorption and good adhesion to copper foil at 240°C.

[0102] On the other hand, when no filler was included, as in Comparative Example 2, or when the amount of filler was small, as in Comparative Example 1, the dielectric loss tangent and coefficient of linear expansion were high. In the case of Comparative Example 3, where polyetherimide resin was not included, the crystallization rate was faster, and the adhesion to the copper foil at 240°C was reduced. As in Comparative Example 4, when the polyarylketone resin was not included, the dielectric loss tangent value increased. As shown in Comparative Example 5, when natural mica without fluorine was used instead of synthetic mica, the dielectric loss tangent and coefficient of linear expansion were higher compared to when synthetic mica was used.

Claims

1. The resin film is made of a resin composition comprising a polyarylketone resin (A), a polyetherimide resin (B) containing para-polyetherimide and meta-polyetherimide, and a fluorine-containing filler (C). A resin film in which the aspect ratio of the fluorine-containing filler (C) in the film is 2 or more and 10 or less, and its content is 25 parts by mass or more per 100 parts by mass of the total content of polyarylketone resin (A) and polyetherimide resin (B).

2. The resin film according to claim 1, comprising 20 to 70 parts by mass of polyarylketone resin (A) and 20 to 70 parts by mass of polyetherimide resin (B) per 100 parts by mass of the resin composition.

3. The resin film according to claim 1 or 2, wherein the fluorine-containing filler (C) has an average particle size of 5 μm or less in a thickness cross-section in the film width direction, with the long axis of the filler as the particle size.

4. The fluorine-containing filler (C) has a bulk density of 0.1 g / cm³. 3 1.0g / cm or more 3 The resin film according to claim 1 or 2, wherein the following applies:

5. The resin film according to claim 1 or 2, wherein the fluorine-containing filler (C) is synthetic mica.

6. The resin film according to claim 1 or 2, wherein the relative crystallinity is 90% or less.

7. The resin film according to claim 1 or 2, wherein the dielectric loss tangent at 10 GHz is 0.005 or less.

8. The resin film according to claim 1 or 2, wherein the relative permittivity at 10 GHz is 3.8 or less.

9. The resin film according to claim 1 or 2, wherein the coefficient of linear expansion is 50 ppm / °C or less.

10. A resin film according to claim 1 or 2, for use on a circuit board.

11. A circuit board material having a structure in which a resin film according to claim 1 or 2 and a conductor are laminated together.

12. A circuit board comprising the circuit board material described in claim 11.

13. An electronic device comprising the circuit board described in claim 12.

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