Resin composition, film, metal-clad laminate, and circuit board

Abstract

Provided is a resin composition that has a low dielectric loss tangent at a high-frequency band and enables the formation of a film having reduced film thickness unevenness. The resin composition contains a thermoplastic liquid crystal polymer. The resin composition has a dielectric loss tangent at 5 GHz of no greater than 0.0015. When, after 12 minutes of measurement at a frequency of 1 rad / s using a rotary rheometer, the frequency is switched to 100 rad / s, the percentage of reduction in the complex viscosity η* 7 minutes after the switch is 20% or less.

Description

Resin composition, film, metal-clad laminate, and circuit board Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2023-080082, filed May 15, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a resin composition containing a polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer), a film containing the resin composition, a metal-clad laminate having a metal layer bonded to at least one surface of the film, and a circuit board having at least an insulating layer and a conductor layer containing the resin composition.

[0003] In recent years, the fields of information processing and communications equipment have seen remarkable development, and as the speed of transmission signals in the circuits used in these fields increases, signals are becoming increasingly higher in frequency, which has led to a demand for substrates used in circuit boards to have excellent dielectric properties in the high-frequency range.

[0004] Thermoplastic liquid crystal polymers have attracted attention as materials with excellent dielectric properties (high-frequency properties) in the high-frequency range. For example, Patent Document 1 (Japanese Patent No. 4639756) discloses an aromatic liquid crystal polyester containing 40 to 74.8 mol% repeating units derived from 2-hydroxy-6-naphthoic acid, 12.5 to 30 mol% repeating units derived from hydroquinone or 4,4'-dihydroxybiphenyl, 12.5 to 30 mol% repeating units derived from 2,6-naphthalenedicarboxylic acid, and 0.2 to 15 mol% repeating units derived from terephthalic acid or 4,4'-biphenyldicarboxylic acid, wherein the number of moles of repeating units derived from terephthalic acid or 4,4'-biphenyldicarboxylic acid is equal to or greater than the number of moles of repeating units derived from 2,6-naphthalenedicarboxylic acid, and having a flow initiation temperature of 300 to 400°C. It also discloses that this aromatic liquid crystal polyester has low dielectric loss and excellent processability into a film shape.

[0005] Patent No. 4639756

[0006] However, although the aromatic liquid crystal polyester described in the examples of Patent Document 1 exhibits a low dielectric loss tangent, the film formed from such an aromatic liquid crystal polyester has a problem in that unevenness in film thickness occurs as an appearance defect.

[0007] Therefore, an object of the present invention is to provide a thermoplastic liquid crystal polymer resin composition that has a low dielectric loss tangent in the high frequency band and enables the formation of a film with reduced thickness unevenness, which is an appearance defect.

[0008] Another object of the present invention is to provide a film containing the resin composition, a metal-clad laminate having a metal layer bonded to at least one surface of the film, and a circuit board comprising a conductor layer and an insulating layer containing the resin composition.

[0009] As a result of intensive research to achieve the above object, the inventors of the present invention have found that a resin composition containing a thermoplastic liquid crystal polymer has a dielectric loss tangent at 5 GHz within a specific range and a complex viscosity η ＊ The present inventors have found that a resin composition having a reduction rate within a specific range can be molded into a film having excellent dielectric properties in the high frequency band and reduced unevenness in film thickness, and have completed the present invention.

[0010] That is, the present invention can be configured in the following aspects: [Aspect 1] A resin composition containing a thermoplastic liquid crystal polymer, which has a dielectric loss tangent at 5 GHz of 0.0015 or less (preferably 0.0014 or less, more preferably 0.0013 or less, even more preferably 0.0012 or less, even more preferably 0.0011 or less, and particularly preferably 0.0010 or less), and which has a complex viscosity η 7 minutes after measurement at a frequency of 1 rad / s under the following measurement conditions using a rotational rheometer at a frequency of 1 rad / s for 12 minutes and then switching to a frequency of 100 rad / s. ＊ The resin composition has a decrease rate of 20% or less (preferably 19% or less, more preferably 18% or less, even more preferably 15% or less, and even more preferably 10% or less). (Measurement conditions) Parallel plate measurement Gap distance: 0.9 mm Plate diameter: 25 mm Measurement temperature: Endothermic peak temperature Tm derived from the thermoplastic liquid crystal polymer measured using a differential scanning calorimeter１ +20°C Strain: 3.0% Soak time when measuring at frequencies of 1 rad / s and 100 rad / s: 0.0 seconds Sampling interval when measuring at a frequency of 100 rad / s: 5.0 seconds / pt Preheating time: 5 minutes [Aspect 2] The resin composition according to aspect 1, wherein the endothermic peak temperature Tm is measured using a capillary rheometer with a capillary diameter of 1.0 mm, a capillary length of 20 mm, and １ +20°C, shear rate 1000 sec －１ A resin composition according to Aspect 1 or 2, wherein the melt viscosity measured under the conditions of a capillary rheometer having a capillary diameter of 1.0 mm, a capillary length of 20 mm, and the endothermic peak temperature Tm １ +20°C, shear rate 1000 sec －１ A resin composition having a melt tension of 0.002 N or more (preferably 0.003 N or more, more preferably 0.004 N or more) when pulled at a preheating time of 5 minutes, a distance from the capillary outlet to the center position of a tension pulley of 200 mm, and a take-up speed of 30 m / min. [Aspect 4] The resin composition according to any one of Aspects 1 to 3, wherein the endothermic peak temperature Tm during the first heating cycle is measured using a differential scanning calorimeter under the following heating and cooling conditions: １ and the endothermic peak temperature Tm during the sixth temperature rise ６ The difference Tm １ -Tm ６ The resin composition according to any one of Aspects 1 to 4, wherein the endothermic peak temperature Tm is 12°C or lower (preferably 10°C or lower, more preferably 9°C or lower, and even more preferably 8°C or lower). (Temperature Raising and Lowering Conditions) Temperature raising conditions: raising the temperature from 25°C to 400°C at a rate of 20°C / min, and holding for 2 minutes after reaching 400°C Temperature lowering conditions: lowering the temperature from 400°C to 25°C at a rate of 20°C / min, and holding for 2 minutes after reaching 25°C. [Aspect 5] The resin composition according to any one of Aspects 1 to 4, wherein the endothermic peak temperature Tm is measured using a capillary rheometer with a capillary diameter of 1.0 mm, a capillary length of 20 mm, and１ +20°C, shear rate 1000 sec －１ a resin composition in which the melt viscosity measured under conditions of a preheating time of 5 minutes is X (Pa s), and the melt viscosity measured under conditions of the same temperature and the same shear rate after leaving the composition to stand in a barrel for 30 minutes at the same temperature is Y (Pa s), and the ratio Y / X is 1.30 or less (preferably 1.25 or less, and more preferably 1.20 or less). [Embodiment 6] The resin composition according to any one of embodiments 1 to 5, wherein, in the thermoplastic liquid crystal polymer, the repeating units represented by the following formula (1) account for 0 to 25 mol % (preferably 0.1 to 25 mol %, more preferably 1 to 20 mol %), the repeating units represented by the following formula (2) account for 25 to 90 mol % (preferably 25 to 80 mol %, more preferably 30 to 75 mol %), the repeating units represented by the following formula (3) account for 0.1 to 40 mol % (preferably 0.1 to 37.5 mol %, more preferably 1 to 35 mol %, even more preferably 5 to 30 mol %), and the repeating units represented by the following formula (4) account for 0.1 to 40 mol % (preferably 0.1 to 37.5 mol %, more preferably 1 to 35 mol %, even more preferably 5 to 30 mol %), relative to the total amount of all repeating units. １ -CO- (1) -O-Ar ２ -CO- (2) -CO-Ar ３ -CO- (3) -O-Ar ４ -O- (4) (wherein, Ar １ is a 1,4-phenylene group, Ar ２ is a 2,6-naphthylene group, and Ar ３ is at least one selected from the group consisting of a 1,4-phenylene group, a 1,3-phenylene group, and a 2,6-naphthylene group, and Ar ４ is at least one selected from the group consisting of a 1,4-phenylene group, a 1,3-phenylene group, and a 4,4'-biphenylylene group, and Ar １ , Ar ２ , Ar ３ and Ar ４ The hydrogen atoms of the aromatic ring are each independently represented by C １－３(Optionally, the repeating units may be substituted with at least one selected from the group consisting of an alkyl group, a halogen atom, and a phenyl group.) [Aspect 7] The resin composition according to Aspect 6, wherein the thermoplastic liquid crystal polymer has a total amount of repeating units containing 2,6-naphthylene groups of 40 mol% or more (preferably 50 mol% or more, more preferably 60 mol% or more) relative to the total amount of all repeating units. [Aspect 8] The resin composition according to any one of Aspects 1 to 7, wherein the resin composition comprises particulate matter. [Aspect 9] The resin composition according to any one of Aspects 1 to 8, wherein the resin composition comprises an additive material, the additive material being at least one selected from the group consisting of a thermoplastic resin, a thermosetting resin, an inorganic compound, and a liquid crystal oligomer. [Aspect 10] The resin composition according to Aspect 9, wherein the thermoplastic resin comprises at least one selected from the group consisting of amorphous polyarylate-based resins, polyphenylene ether-based resins, polyphenylene sulfide-based resins, polyetherimide-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyetheretherketone-based resins, and fluorine-based resins. [Aspect 11] The resin composition according to Aspect 9 or 10, wherein the inorganic compound comprises at least one selected from the group consisting of silica and titanium oxide. [Aspect 12] The resin composition according to any one of Aspects 9 to 11, wherein the resin composition comprises two or more types of inorganic particles having different median sizes. [Aspect 13] The resin composition according to any one of Aspects 9 to 12, wherein the resin composition comprises two or more types of the additive material. [Aspect 14] The resin composition according to any one of Aspects 9 to 13, wherein the weight ratio of the thermoplastic liquid crystal polymer to the additive material (thermoplastic liquid crystal polymer / additive material) is in the range of 63.0 / 37.0 to 94.9 / 5.1 (preferably 66.0 / 34.0 to 94.5 / 5.5, more preferably 72.0 / 28.0 to 93.0 / 7.0). [Aspect 15] A film comprising the resin composition according to any one of Aspects 1 to 14. [Aspect 16] The film according to Aspect 15, having a thickness of 5 to 200 μm (preferably 10 to 150 μm).[Aspect 17] The film according to aspect 15 or 16, wherein the coefficient of variation of thickness in the film width direction as measured with a continuous thickness meter is 1.90% or less (preferably 1.80% or less, more preferably 1.75% or less, even more preferably 1.70% or less, still more preferably 1.40% or less, and particularly preferably 1.30% or less). [Aspect 18] A metal-clad laminate comprising the film according to any one of aspects 15 to 17, and a metal layer bonded to at least one surface of the film. [Aspect 19] A circuit board comprising at least a conductor layer and an insulating layer containing the resin composition according to any one of aspects 1 to 14.

[0011] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one," unless the content clearly dictates otherwise. As used herein, the terms "and / or," "at least one," and "one or more" include any and all combinations of the associated listed items.

[0012] It should be noted that any combination of at least two elements disclosed in the claims and / or the specification is included in the present invention, and in particular any combination of two or more of the claims described in the claims is included in the present invention.

[0013] The resin composition of the present invention has a low dielectric loss tangent in the high frequency band and can be molded into a film with reduced unevenness in film thickness.

[0014] A film containing the resin composition of the present invention has a low dielectric loss tangent in the high frequency band, and therefore can be suitably used as a circuit board material or the like.

[0015] [Thermoplastic liquid crystal polymer] The resin composition contains a thermoplastic liquid crystal polymer. The thermoplastic liquid crystal polymer is composed of a melt-moldable liquid crystal polymer (or a polymer capable of forming an optically anisotropic molten phase), and its chemical structure is not particularly limited as long as it is a melt-moldable liquid crystal polymer, but examples thereof include thermoplastic liquid crystal polyesters and thermoplastic liquid crystal polyester amides in which amide bonds are introduced therein.

[0016] The thermoplastic liquid crystal polymer may also be a polymer in which an isocyanate-derived bond such as an imide bond, a carbonate bond, a carbodiimide bond or an isocyanurate bond is further introduced into an aromatic polyester or an aromatic polyester amide.

[0017] In this specification, the ability to form an optically anisotropic molten phase can be confirmed by, for example, placing a sample on a hot stage, heating it in a nitrogen atmosphere, and observing the light transmitted through the sample.

[0018] Specific examples of thermoplastic liquid crystal polymers include known thermoplastic liquid crystal polyesters and thermoplastic liquid crystal polyester amides derived from the compounds classified as (1) to (4) below and their derivatives. However, it goes without saying that there is an appropriate range for the combination of various raw material compounds in order to form a polymer that can form an optically anisotropic molten phase.

[0019] (1) Aromatic or aliphatic diol (see Table 1 for representative examples)

[0020] (2) Aromatic or aliphatic dicarboxylic acids (see Table 2 for representative examples)

[0021] (3) Aromatic hydroxycarboxylic acids (see Table 3 for representative examples)

[0022] (4) Aromatic diamines, aromatic hydroxyamines, or aromatic aminocarboxylic acids (see Table 4 for representative examples)

[0023] Representative examples of thermoplastic liquid crystal polymers obtained from these raw material compounds include copolymers having the repeating units shown in Tables 5 and 6.

[0024]

[0025]

[0026] Examples of copolymers constituting thermoplastic liquid crystal polymers include copolymers containing repeating units derived from two or more aromatic hydroxycarboxylic acids, and copolymers containing repeating units derived from at least one aromatic hydroxycarboxylic acid, repeating units derived from at least one aromatic dicarboxylic acid, and repeating units derived from at least one aromatic diol and / or aromatic hydroxyamine. For example, copolymers containing at least repeating units derived from p-hydroxybenzoic acid and / or 6-hydroxy-2-naphthoic acid as repeating units derived from aromatic hydroxycarboxylic acids are preferred. The resin composition may contain a mixture of two or more of these copolymers, each with a different combination of repeating units or a different content of repeating units.

[0027] The thermoplastic liquid crystal polymer in the resin composition preferably contains repeating units derived from at least one aromatic hydroxycarboxylic acid, repeating units derived from at least one aromatic dicarboxylic acid, and repeating units derived from at least one aromatic diol and / or aromatic hydroxyamine. In this specification, when the resin composition contains two or more copolymers with different combinations of repeating units or different contents, the repeating units constituting the thermoplastic liquid crystal polymer in the resin composition are expressed as the total repeating units of all of those copolymers. In addition, the content of each repeating unit constituting the thermoplastic liquid crystal polymer in the resin composition is expressed as an average value calculated taking into account the combination, content and molecular weight of the repeating units of each of the two or more copolymers.

[0028] For example, the thermoplastic liquid crystal polymer in the resin composition may contain, relative to the total amount of all repeating units, 0 to 25 mol% of repeating units represented by the following formula (1) (hereinafter, sometimes referred to as repeating units (1)), 25 to 90 mol% of repeating units represented by the following formula (2) (hereinafter, sometimes referred to as repeating units (2)), 0.1 to 40 mol% of repeating units represented by the following formula (3) (hereinafter, sometimes referred to as repeating units (3)), and 0.1 to 40 mol% of repeating units represented by the following formula (4) (hereinafter, sometimes referred to as repeating units (4)). １ -CO- (1) -O-Ar ２ -CO- (2) -CO-Ar ３ -CO- (3) -O-Ar ４ -O- (4) (wherein, Ar １ is a 1,4-phenylene group, and Ar ２ is a 2,6-naphthylene group, and Ar ３ is at least one selected from the group consisting of a 1,4-phenylene group, a 1,3-phenylene group, and a 2,6-naphthylene group, and Ar ４ is at least one selected from the group consisting of a 1,4-phenylene group, a 1,3-phenylene group, and a 4,4'-biphenylylene group, and Ar １ , Ar ２ , Ar ３ and Ar ４ The hydrogen atoms of the aromatic ring are each independently represented by C １－３ It may be substituted with at least one selected from the group consisting of an alkyl group, a halogen atom, and a phenyl group.

[0029] When the thermoplastic liquid crystal polymer in the resin composition contains the repeating unit (1), the content of the repeating unit (1) is preferably 0.1 to 25 mol%, more preferably 1 to 20 mol%, based on the total amount of all repeating units.

[0030] The content of the repeating unit (2) in the thermoplastic liquid crystal polymer in the resin composition may be preferably 25 to 80 mol %, more preferably 30 to 75 mol %, based on the total amount of all repeating units.

[0031] The content of the repeating unit (3) in the thermoplastic liquid crystal polymer in the resin composition is preferably 0.1 to 37.5 mol%, more preferably 1 to 35 mol%, and even more preferably 5 to 30 mol%, based on the total amount of all repeating units.

[0032] The content of the repeating unit (4) in the thermoplastic liquid crystal polymer in the resin composition is preferably 0.1 to 37.5 mol%, more preferably 1 to 35 mol%, and even more preferably 5 to 30 mol%, based on the total amount of all repeating units.

[0033] From the viewpoint of easily increasing the molecular weight of the thermoplastic liquid crystal polymer and improving the mechanical properties, the molar ratio of the repeating unit (3) to the repeating unit (4) in the thermoplastic liquid crystal polymer in the resin composition, as (3) / (4), may be 95 / 100 to 100 / 95, preferably 98 / 100 to 100 / 98, more preferably 99 / 100 to 100 / 99, and even more preferably 100 / 100.

[0034] The thermoplastic liquid crystal polymer in the resin composition preferably has a naphthalene skeleton as a repeating unit from the viewpoint of reducing the dielectric loss tangent. For example, the total amount of repeating units containing 2,6-naphthylene groups in the thermoplastic liquid crystal polymer in the resin composition may be 40 mol% or more, preferably 50 mol% or more, and more preferably 60 mol% or more, based on the total amount of all repeating units. Furthermore, from the viewpoint of adjusting the melting point and improving melt moldability, it may be 95 mol% or less, preferably 90 mol% or less, and more preferably 85 mol% or less. Examples of repeating units containing 2,6-naphthylene groups include repeating unit (2) (a repeating unit derived from 6-hydroxy-2-naphthoic acid) and Ar ３is a 2,6-naphthylene group (repeating unit derived from 2,6-naphthalenedicarboxylic acid), is preferred.

[0035] In the thermoplastic liquid crystal polymer in the resin composition, each of the repeating units (1) to (4) may contain two or more kinds. The content of each repeating unit represents the content of all repeating units corresponding to each repeating unit. For example, the thermoplastic liquid crystal polymer in the resin composition contains Ar as the repeating unit (3). ３ When the repeating unit (3) contains two types of repeating units, a 1,4-phenylene group repeating unit and a 2,6-naphthylene group repeating unit, the content of the repeating unit (3) represents the total content of these repeating units.

[0036] The thermoplastic liquid crystal polymer in the resin composition may contain two or more types of repeating unit (3) and / or two or more types of repeating unit (4).

[0037] The thermoplastic liquid crystal polymer in the resin composition may have repeating units other than the repeating units (1) to (4), but the total content of the repeating units (1) to (4) relative to the total amount of all repeating units may be, for example, 95 mol% or more, preferably 98 mol% or more, more preferably 99 mol% or more, and even more preferably 100 mol%.

[0038] The thermoplastic liquid crystal polymer can be synthesized by a known polycondensation method. As the monomer to be subjected to polycondensation, various aromatic diols, aromatic dicarboxylic acids, aromatic hydroxycarboxylic acids, aromatic hydroxyamines, etc. may be used, and carboxylic acid derivatives such as acylated products of hydroxyl groups, esterified products of carboxyl groups, acid halides, and acid anhydrides, which are obtained by activating the terminals of these monomers, may also be used.

[0039] The polycondensation may be carried out in the presence of various polymerization catalysts, such as organotin catalysts (dialkyltin oxides, etc.), antimony catalysts (antimony trioxide, etc.), titanium catalysts (titanium dioxide, etc.), alkali metal salts or alkaline earth metal salts of carboxylic acids (potassium acetate, etc.), Lewis acid salts (BF ３etc.), organic compound catalysts (N,N-dimethylaminopyridine, 1-methylimidazole, etc.), etc.

[0040] After polycondensation is carried out by melt polymerization, solid-state polymerization may be carried out by, for example, extracting the polymer obtained by the melt polymerization step, pulverizing it into powder or flakes, or granulating it in an extruder into pellets, and then heat-treating it in a solid state under vacuum or in an inert atmosphere such as nitrogen.

[0041] [Resin Composition] The resin composition has a dielectric loss tangent of 0.0015 or less at 5 GHz and a complex viscosity η ＊ The reduction rate of the thickness of the resin composition is 20% or less. Such a resin composition can be molded into a film having excellent dielectric properties in the high frequency band and reduced unevenness in film thickness.

[0042] In the present invention, the inventors have discovered a problem that when a conventional thermoplastic liquid crystal polymer having a low dielectric loss tangent in the high frequency band is molded into a film, the resulting film is prone to uneven thickness. The reason for this is thought to be that thermoplastic liquid crystal polymers with a low dielectric loss tangent in the conventional technology tend to have weak polarization in the molecular chain direction, and the liquid crystal domains, which are regions where the molecular chains of such thermoplastic liquid crystal polymers are aligned, are less stable under shear during film formation, resulting in uneven thickness as an appearance defect in the molded film. Thus, the inventors have discovered a trade-off relationship in which the properties of a thermoplastic liquid crystal polymer that exhibits a low dielectric loss tangent in the high frequency band are disadvantageous in film formation. The inventors have discovered that the stability of the liquid crystal domains of a thermoplastic liquid crystal polymer under shear is affected by the complex viscosity η ＊ and found that the complex viscosity η in a resin composition containing a thermoplastic liquid crystal polymer is correlated with the reduction rate of ＊ By controlling the rate of decrease in dielectric constant within a specific range, we have discovered a resin composition that exhibits a low dielectric loss tangent in the high frequency band, while maintaining high stability of the liquid crystal domains even under shear stress and enabling the formation of films with reduced film thickness unevenness.

[0043] The resin composition may have a dielectric dissipation factor at 5 GHz of preferably 0.0014 or less, more preferably 0.0013 or less, even more preferably 0.0012 or less, even more preferably 0.0011 or less, particularly preferably 0.0010 or less, and particularly preferably 0.0009 or less. The lower the dielectric dissipation factor at 5 GHz, the better. While the lower limit is not particularly limited, it may be, for example, 0.0001 or more. In this specification, the dielectric dissipation factor of a resin composition is a value measured using a film-shaped (or sheet-shaped) sample in one in-plane direction (X direction) and a perpendicular in-plane direction (Y direction), and calculated as the average value of the X and Y directions. Specifically, this value is measured by the method described in the Examples below. When the sample is not in a film shape, the dielectric dissipation factor of the resin composition can be measured by molding the sample into a film shape (e.g., by heat pressing, etc.) to prepare a sample.

[0044] The resin composition has a complex viscosity η ＊ The decrease rate of the complex viscosity η may be preferably 19% or less, more preferably 18% or less, even more preferably 15% or less, and even more preferably 10% or less. ＊ The lower limit of the decrease rate of the complex viscosity η is not particularly limited, and may be, for example, 0.1% or more, or 0.2% or more. ＊ The rate of decrease was measured using a rotational rheometer with a parallel plate having a plate diameter of 25 mm and a gap distance of 0.9 mm. The measurement temperature was the endothermic peak temperature Tm １ The complex viscosity η is measured by the following procedure under the conditions of +20°C, strain: 3.0%, soak time: 0.0 seconds when measuring at frequencies of 1 rad / s and 100 rad / s, and sampling interval: 5.0 seconds / pt when measuring at a frequency of 100 rad / s. That is, first, the apparatus is preheated for 5 minutes after the temperature inside the apparatus reaches the measurement temperature, and then measurement is carried out at a frequency of 1 rad / s for 12 minutes, and then the complex viscosity η is measured at the time when the frequency is switched to 100 rad / s. ＊ Ｘ , and the complex viscosity η 7 minutes after switching ＊Ｙ By measuring the complex viscosity η ＊ The rate of decrease is (η ＊ Ｘ -η ＊ Ｙ ) / η ＊ Ｘ This is the value calculated as x100.

[0045] Also, the endothermic peak temperature Tm １ Tm refers to the temperature of the endothermic peak derived from the thermoplastic liquid crystal polymer contained in the resin composition, which appears when the temperature is raised from 25 ° C. to 400 ° C. at a rate of 20 ° C. / min in differential scanning calorimetry of the resin composition. Note that the "endothermic peak temperature" is the temperature at the apex of the endothermic peak. When multiple endothermic peaks derived from thermoplastic liquid crystal polymers are observed in a sample, the endothermic peak temperature derived from the thermoplastic liquid crystal polymer with the largest weight ratio in the sample is referred to as Tm １ In addition, when a plurality of endothermic peaks derived from the thermoplastic liquid crystal polymer are observed in the sample and the weight ratios of the plurality of thermoplastic liquid crystal polymers belonging to each endothermic peak are equal, the lowest endothermic peak temperature is defined as Tm １ The endothermic peak temperature Tm １ may be, for example, in the range of 260 to 370°C, preferably in the range of 280 to 360°C, and more preferably in the range of 290 to 350°C.

[0046] From the viewpoint of melt moldability, the resin composition was measured using a capillary rheometer with a capillary diameter of 1.0 mm, a capillary length of 20 mm, and an endothermic peak temperature Tm １ +20°C, shear rate 1000 sec －１ The melt viscosity measured under conditions of a preheating time of 5 minutes may be 30 to 120 Pa·s. The melt viscosity of the resin composition may be preferably 35 to 80 Pa·s, more preferably 40 to 70 Pa·s, and even more preferably 42 to 65 Pa·s. If this value is too high, retention of the molten resin may occur during the melt molding process, and if it is too low, sufficient melt tension may not be exhibited during film formation. The melt viscosity is a value measured by the method described in the Examples below.

[0047] From the viewpoint of melt moldability, the resin composition was measured using a capillary rheometer with a capillary diameter of 1.0 mm, a capillary length of 20 mm, and an endothermic peak temperature Tm １ +20°C, shear rate 1000 sec －１ When the melt viscosity measured under conditions of a preheating time of 5 minutes is defined as X (Pa s), and then the melt viscosity measured under conditions of the same temperature and shear rate after leaving the resin composition to stand in the barrel for 30 minutes at the same temperature is defined as Y (Pa s), the ratio Y / X may be 1.30 or less. If the melt viscosity ratio Y / X is too large, the resin composition will thicken upon heating, which tends to cause the molten resin composition to stagnate during melt molding, resulting in poor melt moldability. The melt viscosity ratio Y / X of the resin composition may preferably be 1.25 or less, more preferably 1.20 or less. Furthermore, the lower limit of the melt viscosity ratio Y / X of the resin composition is not particularly limited, but may be, for example, 1.00 or more.

[0048] The resin composition was measured using a capillary rheometer at an endothermic peak temperature Tm １ +20°C, shear rate 1000 sec －１ The melt tension when pulled at a take-up speed of 30 m / min under conditions of a preheating time of 5 minutes may be 0.002 N or more. If the melt tension is too low, it may lead to film formation problems during melt molding, such as draw resonance occurring during film molding using a T-die or unstable bubbles during inflation molding. The melt tension of the resin composition may be preferably 0.003 N or more, more preferably 0.004 N or more. Furthermore, the upper limit of the melt tension of the resin composition is not particularly limited, but may be, for example, 0.01 N or less.

[0049] From the viewpoint of heat resistance, the resin composition is measured using a differential scanning calorimeter at the endothermic peak temperature Tm １ and the endothermic peak temperature Tm during the sixth temperature rise ６ The difference Tm １ -Tm６ These endothermic peak temperatures may be determined by measuring the temperature of the resin composition by differential scanning calorimetry, in which the temperature is increased from 25° C. to 400° C. at a rate of 20° C. / min, and then maintained for 2 minutes after reaching 400° C.; and then the temperature is decreased from 400° C. to 25° C. at a rate of 20° C. / min, and then maintained for 2 minutes after reaching 25° C.; and when this temperature increase and decrease cycle is repeated six times, the temperature of the endothermic peak during the first temperature increase is determined as Tm １ (°C), the temperature of the endothermic peak during the sixth temperature rise is Tm ６ (°C). The difference in endothermic peak temperature Tm １ -Tm ６ is an index showing how much the endothermic peak temperature, which means the melting point of the thermoplastic liquid crystal polymer, has decreased due to the thermal history caused by the temperature rise and fall cycle. If this is too large, it is expected that the thermoplastic liquid crystal polymer will undergo ester exchange due to heating, and the heat resistance will tend to be poor due to the thermal history. １ -Tm ６ may be preferably 10°C or less, more preferably 9°C or less, and even more preferably 8°C or less.

[0050] The resin composition has a dielectric loss tangent and a complex viscosity η ＊As long as the rate of decrease is within a specific range, it is not limited, but may contain, for example, particulate matter. In this specification, particulate matter refers to a component that is dispersed and incompatible at room temperature in a matrix of a thermoplastic liquid crystal polymer having a predetermined composition (combination of repeating units and their content) contained as a main component in the resin composition. The shape of the particulate matter is not particularly limited, and it may exist in any particle shape, such as spherical, cylindrical, honeycomb, fibrous, or irregular. It is sufficient that the particulate matter is confirmed to be dispersed in the matrix of the thermoplastic liquid crystal polymer contained as a main component. For example, the average particle diameter of the particulate matter may be 50 μm or less, preferably 30 μm or less, more preferably 10 μm or less, and the lower limit is not particularly limited, but may be, for example, 0.01 μm or more. The average particle diameter of the particulate matter is calculated as the average value of the maximum diameters of the particulate matter dispersed in the matrix using image analysis with an electron microscope (e.g., SEM). The particulate matter may include not only the additive materials described below, but also particulate thermoplastic liquid crystal polymers having a different composition from the thermoplastic liquid crystal polymer contained as the main component.In this specification, the term "main component" refers to the component that is contained in the resin composition at the highest content.In addition, even if the thermoplastic liquid crystal polymer is contained as a particulate matter, as described above, the repeating unit and its content of the thermoplastic liquid crystal polymer in the resin composition are expressed as the average value of all repeating units and their contents of all thermoplastic liquid crystal polymers contained in the resin composition, without distinguishing between the main component and the particulate matter.

[0051] The resin composition has a dielectric loss tangent and a complex viscosity η ＊ The additive material is not limited as long as the reduction rate is within a specific range, but may contain, for example, an additive material. The additive material is a component other than the thermoplastic liquid crystal polymer, and may be at least one selected from the group consisting of a thermoplastic resin, a thermosetting resin, an inorganic compound, and a liquid crystal oligomer. The additive material is preferably at least one selected from the group consisting of a thermoplastic resin and an inorganic compound.

[0052] The thermoplastic resin is not particularly limited as long as it is a thermoplastic resin other than the above-mentioned thermoplastic liquid crystal polymer, but examples thereof include amorphous polyarylate resins, polyphenylene ether resins, polyphenylene sulfide resins, polyetherimide resins, polyethersulfone resins, polyetheretherketone resins, polycarbonate resins, and fluorine-based resins. The amorphous polyarylate resin refers to an amorphous aromatic polyester obtained by polycondensation of a dihydric phenol and an aromatic dicarboxylic acid, such as a copolymer of bisphenol A with terephthalic acid and isophthalic acid. The fluorine-based resin refers to a polymer having fluorine atoms in the molecular chain, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene (PFA). Of these thermoplastic resins, amorphous polyarylate resins, polyphenylene ether resins, and fluorine-based resins are preferred.

[0053] Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, thermosetting polyimide resins, bismaleimide resins, phenol resins, melamine resins, and thermosetting polyurethane resins.

[0054] Examples of inorganic compounds include silica (silicon oxide), alumina (aluminum oxide), titanium oxide, zirconium oxide, silicon carbide, aluminum nitride, boron nitride, barium titanate, glass, mica, talc, etc. Among these inorganic compounds, at least one selected from the group consisting of silica and titanium oxide is preferred, and silica is more preferred.

[0055] The inorganic compound is preferably contained as inorganic particles. The median diameter of the inorganic particles may be 0.01 to 10 μm, preferably 0.03 to 5 μm, and more preferably 0.05 to 1 μm. In this specification, the median diameter of the inorganic particles refers to the particle diameter at which the cumulative value reaches 50% in the particle size distribution measured by a laser diffraction / scattering method.

[0056] The resin composition may contain two or more types of inorganic particles having different median diameters. The inorganic particles having different median diameters may be the same type of inorganic particles having different median diameters, or may be different types of inorganic particles having different median diameters.

[0057] The liquid crystal oligomer refers to an oligomer of 10 or less that is composed of repeating units selected from the various repeating units exemplified for the thermoplastic liquid crystal polymer described above, and is produced by a known polymerization method such as polycondensation of the raw material compounds (monomers) described above. The term "10 or less" means that the total number of repeating units in one molecule is 10 or less.

[0058] The resin composition may contain two or more additive materials, which may have different chemical structures, for example, two or more thermoplastic resins, thermosetting resins, inorganic compounds, or liquid crystalline oligomers (e.g., two or more thermoplastic resins and two or more inorganic compounds), or at least two or more selected from the group consisting of thermoplastic resins, thermosetting resins, inorganic compounds, and liquid crystalline oligomers (e.g., one or more thermoplastic resins and one or more inorganic compounds, one or more thermoplastic resins and one or more thermosetting resins).

[0059] The resin composition has a dielectric loss tangent and a complex viscosity η depending on the additive material used and its content. ＊ The reduction rate can be adjusted, for example, the weight ratio of the thermoplastic liquid crystal polymer to the additive material (thermoplastic liquid crystal polymer / additive material) may be in the range of 63.0 / 37.0 to 94.9 / 5.1, preferably 66.0 / 34.0 to 94.5 / 5.5, more preferably 72.0 / 28.0 to 93.0 / 7.0. In this specification, when the resin composition contains two or more additive materials, this weight ratio is calculated based on the total amount of all additive materials.

[0060] In one embodiment, the resin composition may contain a thermoplastic liquid crystal polymer and an inorganic compound. The inorganic compound may be any of the above-mentioned inorganic compounds, and preferably inorganic particles, such as at least one selected from the group consisting of silica particles and titanium oxide particles. Two or more types of these inorganic particles with different median sizes may also be used. For example, the resin composition may contain silica particles and titanium oxide particles with different median sizes, or may contain two or more types of silica particles with different median sizes.

[0061] In another embodiment, the resin composition may contain a thermoplastic liquid crystal polymer and a thermoplastic resin. The thermoplastic resin may be any of the above-mentioned thermoplastic resins, and is preferably at least one selected from the group consisting of an amorphous polyarylate resin, a polyphenylene ether resin, and a fluorine-containing resin.

[0062] The resin composition may also contain a thermoplastic resin in the form of thermoplastic resin particles, such as fluorine-based resin particles.

[0063] In another embodiment, the resin composition may contain a thermoplastic liquid crystal polymer, a thermoplastic resin, and an inorganic compound. For example, the resin composition may contain at least one thermoplastic resin selected from the group consisting of an amorphous polyarylate resin and a polyphenylene ether resin, and may contain silica as an inorganic compound.

[0064] The resin composition may contain two or more thermoplastic liquid crystal polymers having different compositions. For example, the resin composition may contain a thermoplastic liquid crystal polymer as a particulate material as a component other than the thermoplastic liquid crystal polymer as the main component.

[0065] When the resin composition contains a thermoplastic liquid crystal polymer and an inorganic compound, the weight ratio of the thermoplastic liquid crystal polymer to the inorganic compound (thermoplastic liquid crystal polymer / inorganic compound) may be in the range of 66.0 / 34.0 to 96.0 / 4.0, preferably 80.0 / 20.0 to 94.9 / 5.1, more preferably 90.0 / 10.0 to 94.0 / 6.0.

[0066] The content of the inorganic compound in the resin composition may be 0 to 30% by weight, preferably 1 to 15% by weight, and more preferably 4.5 to 9.5% by weight, based on the weight of the solid content in the resin composition.

[0067] When the resin composition contains a thermoplastic liquid crystal polymer and a thermoplastic resin, the weight ratio of the thermoplastic liquid crystal polymer to the thermoplastic resin (thermoplastic liquid crystal polymer / thermoplastic resin) may be in the range of 60.0 / 40.0 to 96.0 / 4.0, preferably 63.0 / 37.0 to 94.9 / 5.1, more preferably 65.0 / 35.0 to 94.0 / 6.0.

[0068] The content of the thermoplastic resin in the resin composition may be 0 to 37% by weight, preferably 3 to 30% by weight, and more preferably 5 to 28% by weight, based on the weight of the solid content in the resin composition.

[0069] The total content of the inorganic compound and the thermoplastic resin in the resin composition may be 4 to 37% by weight, preferably 5 to 30% by weight, and more preferably 6 to 20% by weight, based on the weight of the solid content in the resin composition.

[0070] [Method for producing resin composition] The resin composition can be produced by mixing the above-mentioned thermoplastic liquid crystal polymer and additive materials by a known method. The resin composition may be produced by mixing two or more thermoplastic liquid crystal polymers with different compositions. In addition, these thermoplastic liquid crystal polymers may be obtained by melt polymerization and then mixed with a thermoplastic liquid crystal polymer whose polymerization degree has been adjusted by solid-state polymerization.

[0071] The resin composition may be produced by melt-kneading raw materials such as the above-mentioned thermoplastic liquid crystal polymer and additive materials in an extruder.The extruder used for melt-kneading is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw extruder, and a multi-screw extruder.Among these, a twin-screw extruder is preferred from the viewpoint of uniformly dispersing the auxiliary components (e.g., additive materials) in the resin composition.

[0072] From the viewpoint of uniformly mixing the raw material components, the L / D of the extruder is preferably 10 to 100, more preferably 15 to 80, and even more preferably 20 to 60. When the L / D is 10 or more, a better kneading state is more easily obtained. Furthermore, when the L / D is 100 or less, shear heat generation during kneading can be reduced, and thermal decomposition of each component in the resin composition can be suppressed. Here, L [unit: mm] is the length of the cylinder of the extruder, and D [unit: mm] is the inner diameter of the cylinder of the extruder.

[0073] The extruder preferably has one or more open vents. By using such an extruder, decomposition products and volatile components can be sucked through the open vents, thereby improving the quality of the resulting resin composition. In order to suck decomposition products and the like through the open vents, for example, it is preferable to place the open vents in a reduced pressure state. When reducing the pressure, the pressure is preferably 0.1 to 90 kPa, more preferably 0.3 to 80 kPa, even more preferably 0.5 to 50 kPa, and particularly preferably 0.7 to 10 kPa. By setting the pressure of the open vents to 90 kPa or less, the amount of remaining decomposition products and volatile components can be reduced. Furthermore, by setting the pressure of the open vents to 0.1 kPa or more, the productivity of the resin composition can be improved.

[0074] The extruder can be connected to a known die depending on the desired shape of the resin composition. For example, a strand die can be connected and the extruded resin composition can be cut to a desired length to obtain a granular or columnar resin composition.

[0075] The method for feeding the raw materials for the resin composition to the extruder is not particularly limited, and all the raw materials may be fed together from a gravimetric feeder to a raw material feed hopper, or each or some of the raw materials may be fed together to a raw material feed hopper using two or more gravimetric feeders. When a premix is ​​produced by mixing some or all of the raw materials, the production method is not particularly limited, and the raw materials can be mixed using a known mixer such as a tumbler mixer or a Henschel mixer, for example.

[0076] An example of the screw configuration of the extruder is one having a conveying section equipped with a full-flight screw segment that conveys the raw materials and kneaded product of the resin composition, and a kneading section equipped with a kneading disk (forward, neutral, reverse, etc.) that kneads the raw materials of the resin composition and a screw segment in which the feeding direction of the molten resin is reversed (a screw segment with a reverse spiral winding direction, reverse flight). From the viewpoint of uniformly dispersing the secondary components (e.g., additive materials) in the resin composition, it is preferable to have one or more kneading sections. In addition, in order to avoid an increase in resin pressure at the twin-screw extruder head, it is preferable that the conveying section be installed behind the kneading section that conveys the kneaded product of the resin composition to the die section or the like.

[0077] From the viewpoint of preventing deterioration of the resin composition, the resin composition may be melt-kneaded while passing an inert gas through the extruder.

[0078] A polymer filter may be installed downstream of the extruder to remove foreign matter, and examples of the polymer filter include a candle-type polymer filter and a leaf-disk-type polymer filter.

[0079] [Film] The resin composition described above can be suitably used for forming a film. The film can be produced by extrusion molding the resin composition. Any method can be used as the extrusion molding method, but well-known methods such as the T-die method and inflation method are industrially advantageous. In particular, the inflation method applies stress not only in the mechanical axis direction of the film (hereinafter abbreviated as MD direction) but also in a direction perpendicular to this (hereinafter abbreviated as TD direction), allowing for uniform stretching in the MD and TD directions, thereby producing a film with controlled molecular orientation, dielectric properties, etc. in the MD and TD directions.

[0080] Furthermore, the film may be stretched as needed after extrusion molding. The stretching method itself is known, and either biaxial stretching or uniaxial stretching may be used, but biaxial stretching is preferred because it is easier to control the degree of molecular orientation. For stretching, known uniaxial stretching machines, simultaneous biaxial stretching machines, sequential biaxial stretching machines, etc. may be used.

[0081] In extrusion molding, a stretching process may be performed to control the orientation. For example, in extrusion molding using a T-die method, the molten sheet extruded from the T-die may be stretched not only in the MD direction of the thermoplastic liquid crystal polymer film but also in both the TD direction and the MD direction simultaneously to form a film, or the molten sheet extruded from the T-die may be stretched in the MD direction once and then in the TD direction to form a film.

[0082] In addition, in extrusion molding by the inflation method, a cylindrical sheet melt-extruded from a ring die may be stretched at a predetermined draw ratio (corresponding to the stretch ratio in the MD direction) and blow ratio (corresponding to the stretch ratio in the TD direction) to form a film.

[0083] The film thus obtained is composed of the above-mentioned resin composition. The above-mentioned resin composition has a complex viscosity η ＊ Since the rate of decrease in thickness is low within a specific range, the stability of the liquid crystal domains under shear is high, and it is possible to form a film with reduced film thickness unevenness. For example, the film may have a thickness variation coefficient in the film width direction, as measured with a continuous thickness meter, of 1.90% or less, preferably 1.80% or less, more preferably 1.75% or less, even more preferably 1.70% or less, still more preferably 1.40% or less, and particularly preferably 1.30% or less. In this specification, the thickness variation coefficient is calculated using the thickness measurement data in the film width direction as thickness standard deviation / average thickness x 100, and is measured by the method described in the Examples below.

[0084] The thickness of the film can be appropriately set depending on the application, and can be selected from a wide range of, for example, 1 to 500 μm. However, taking into consideration that the film will be used as a material for the insulating layer of a circuit board, the thickness may be preferably 5 to 200 μm, and more preferably 10 to 150 μm.

[0085] The melting point (Tm) of the film may be in the range of 260 to 370° C., preferably in the range of 280 to 360° C., and more preferably in the range of 285 to 350° C. The melting point Tm of the film is determined as the temperature of an endothermic peak derived from the thermoplastic liquid crystal polymer that appears when a film sample is heated from 25° C. at a rate of 20° C. / min using a differential scanning calorimeter.

[0086] [Metal-clad laminate] The above-mentioned film can be used in a metal-clad laminate having a metal layer bonded to at least one surface thereof. The metal-clad laminate may be a single-sided metal-clad laminate having a metal layer on one side of the film, or a double-sided metal-clad laminate having metal layers on both sides of the film. The metal-clad laminate may be formed by laminating the film and the metal layer via an adhesive layer (e.g., adhesive), but from the viewpoint of reducing the thickness as a circuit board manufacturing material, a metal-clad laminate in which the film and the metal layer are directly laminated without an adhesive layer is preferred.

[0087] The metal-clad laminate may be produced by adhering a metal foil to the above-mentioned film by thermocompression bonding to form a metal layer, by forming a metal layer by sputtering, vapor deposition, electroless plating, etc., or by casting a resin composition onto a metal foil.

[0088] The metal forming the metal layer is not particularly limited and may be, for example, gold, silver, copper, iron, tin, nickel, aluminum, chromium, or an alloy metal thereof, etc. These metals may contain other metal species at 2000 ppm by mass or less, and may contain inevitable impurities.

[0089] When a metal foil is used as the metal layer, it may be, for example, a metal foil formed of the above metals, and copper foil or stainless steel foil is preferred from the viewpoints of conductivity, handleability, cost, etc. Copper foil produced by a rolling method or an electrolytic method can be used. In addition, the metal foil may be subjected to a surface treatment such as a conventional roughening treatment within a range that does not impair the high-frequency characteristics of the metal clad laminate of the present invention.

[0090] In sputtering or vapor deposition, a metal is sputtered or vapor-deposited to bring the metal parts into contact with each other and bond them together. Sputtering or vapor deposition is a well-known method in the field of circuit board manufacturing. Examples of metals for sputtering or vapor deposition include copper, aluminum, gold, tin, and chromium.

[0091] Electroless plating is a process of bonding two materials by depositing a metal from a solution containing metal ions. Electroless plating is a well-known method in the field of manufacturing plated products on non-conductive materials (such as plastics and ceramics). Examples of metals that can be used include copper, nickel, cobalt, gold, tin, and chromium.

[0092] The metal-clad laminate can be effectively used as a material for parts used in the fields of electricity and electronics, office equipment and precision instruments, power semiconductors, etc., for example, as a circuit board material.

[0093] [Circuit Board] The above-mentioned resin composition can be used for a circuit board including at least an insulating layer containing the resin composition and a conductor layer. For example, a circuit board can be produced by forming a conductor pattern on the surface of the above-mentioned film. Alternatively, a circuit board can be produced by processing the metal layer of the above-mentioned metal-clad laminate into a wiring circuit. Known methods can be used as the circuit processing method, and for example, a circuit can be formed by etching the metal layer on the film using a subtractive method.

[0094] The conductor layer is formed, for example, from a metal having at least electrical conductivity, and a circuit is formed on this conductor layer using a known circuit processing method. The conductor forming the conductor layer may be any of various electrically conductive metals, such as gold, silver, copper, iron, tin, nickel, aluminum, chromium, or alloys thereof.

[0095] The circuit board can be used as various high-frequency circuit boards. The circuit board may also be a circuit board (or a semiconductor device mounting board) on which a semiconductor device (e.g., an IC chip) is mounted. Since the dielectric loss tangent of the circuit board is controlled to be low, the circuit board may be used for various transmission lines, such as known or conventional transmission lines such as coaxial lines, strip lines, microstrip lines, coplanar lines, and parallel lines, or for antennas (e.g., microwave or millimeter wave antennas). The circuit board may also be used for antenna devices in which an antenna and a transmission line are integrated. For example, the circuit board may be used for various sensors, particularly for automotive radar.

[0096] Examples of antennas include antennas that utilize millimeter waves or microwaves, such as waveguide slot antennas, horn antennas, lens antennas, print antennas, triplate antennas, microstrip antennas, and patch antennas.

[0097] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0098] [Endothermic Peak Temperature] Using a differential scanning calorimeter ("DSC Q2000" manufactured by TA Instruments Japan Co., Ltd.), 5.0 mg of the resin composition was placed in a sample container, and the temperature was increased and decreased six times under the following temperature increase and decrease conditions. At that time, the temperature of the endothermic peak derived from the thermoplastic liquid crystal polymer during the first temperature increase was determined as Tm １ (°C), the endothermic peak derived from the thermoplastic liquid crystal polymer during the sixth temperature rise is Tm ６ (°C). From these values, Tm １ -Tm ６ (°C) was calculated. (Temperature increase and decrease conditions) Temperature increase conditions: The temperature was increased from 25°C to 400°C at a rate of 20°C / min, and after reaching 400°C, it was held for 2 minutes. Temperature decrease conditions: The temperature was decreased from 400°C to 25°C at a rate of 20°C / min, and after reaching 25°C, it was held for 2 minutes.

[0099] [Film Melting Point] Using a differential scanning calorimeter ("DSC Q2000" manufactured by TA Instruments Japan Co., Ltd.), a sample of a predetermined size was taken from the films obtained in the Examples and Comparative Examples and placed in a sample container. The temperature was raised from 25°C to 400°C at a rate of 20°C / min, and the temperature of the endothermic peak that appeared when the temperature was raised was taken as the melting point Tm of the film.

[0100] [Dielectric Loss Tangent] The films obtained in the examples and comparative examples were cut in the MD direction to obtain sample pieces 8 cm long and 2 mm wide. Similarly, samples were cut in the TD direction to obtain sample pieces 8 cm long and 2 mm wide. The dielectric loss tangent was measured at a frequency of 5 GHz using a cavity resonator perturbation method. A 5 GHz cavity resonator (manufactured by Kanto Electronics Application Development Co., Ltd.) was connected to a network analyzer ("E8362B" manufactured by Agilent Technology), and the sample pieces were inserted into the cavity resonator. Measurements were performed at 25°C to measure the dielectric loss tangent in the MD and TD directions, and the average value was calculated as the dielectric loss tangent.

[0101] [Complex viscosity η ＊ (Sample Preparation Method) The resin compositions obtained in the Examples and Comparative Examples were １ +15 to Tm １ +30°C (Tm １ indicates the endothermic peak temperature derived from the thermoplastic liquid crystal polymer during the first temperature rise measured above), under the condition of a pressure of 100 kg / cm ２ The sheet was then punched into a disk having a diameter of 25 mm to obtain a measurement sample.

[0102] (Measurement Method) Using a rotational rheometer ("ARES-G2" manufactured by TA Instruments Japan Co., Ltd.), a measurement sample was set on parallel plates with a plate diameter of 25 mm, and the gap distance was set to 0.9 mm. The measurement temperature was set to the endothermic peak temperature Tm of the resin composition obtained above. １Measurements were performed using the following conditions: +20°C, strain: 3.0%, soak time: 0.0 seconds when measuring at frequencies of 1 rad / s and 100 rad / s, sampling interval: 5.0 seconds / pt when measuring at a frequency of 100 rad / s. First, the device was preheated for 5 minutes after reaching the measurement temperature. Next, measurements were performed at a frequency of 1 rad / s for 12 minutes, and then the frequency was switched to 100 rad / s and the measurement was continued. The complex viscosity at the time of switching to the frequency of 100 rad / s was defined as η ＊ Ｘ The complex viscosity 7 minutes after switching is η ＊ Ｙ The complex viscosity η ＊ The reduction rate (%) of (η ＊ Ｘ -η ＊ Ｙ ) / η ＊ Ｘ ×100.

[0103] [Melt Viscosity] The resin compositions obtained in the Examples and Comparative Examples were dried for 16 hours using a vacuum dryer at 140°C and a reduced pressure of 1.4 kPa. Using a capillary rheometer ("Capillograph (registered trademark) F-2" manufactured by Toyo Seiki Seisaku-sho, Ltd.; barrel diameter: 15 mm), the resin compositions were charged into the barrel, and the measurement temperature was the endothermic peak temperature Tm of the resin composition obtained above. １ Measurement was carried out under the condition of +20°C by the following procedure. After the temperature inside the barrel reached the measurement temperature, the sample was preheated in the barrel for 5 minutes, and then heated at the measurement temperature and a shear rate of 1000 sec. －１ The melt viscosity was measured under the conditions above, and this melt viscosity was designated as X (Pa·s).

[0104] After measuring the melt viscosity X, the piston was stopped and the molten resin was allowed to stand in the barrel for 30 minutes, after which the melt viscosity was measured under the same temperature and shear rate conditions, and this melt viscosity was designated as Y (Pa s). The melt viscosity ratio Y / X was calculated.

[0105] [Melt tension] The resin compositions obtained in the examples and comparative examples were dried for 16 hours at 140°C and a reduced pressure of 1.4 kPa using a vacuum dryer. The resin compositions were charged into a barrel of a capillary rheometer ("Capillograph (registered trademark) F-2" manufactured by Toyo Seiki Seisaku-sho, Ltd.; barrel diameter: 15 mm), and the endothermic peak temperature Tm of the resin composition obtained above was measured. １ Measurements were carried out under the following conditions: +20°C, distance from the capillary outlet to the center of the tension pulley: 200 mm. After the temperature inside the barrel reached the measurement temperature, the barrel was preheated for 5 minutes, and then the measurement temperature was maintained at a piston speed of 33.33 mm / min (shear rate 1000 sec). －１ ) Under the condition, the take-up speed is changed from 25 m / min to 0.02778 m / s ２ The melt tension was measured when the film was taken up at a take-up speed of 50 m / min while being raised at this rate, and the melt tension (N) was read when the film was taken up at a take-up speed of 30 m / min.

[0106] [Film Thickness] Five sample pieces with a TD width of 210 mm and an MD width of 30 mm were cut out from the films obtained in the Examples and Comparative Examples. Using a desktop thickness gauge ("RC-1W" manufactured by Meisan Co., Ltd.), the five sample pieces were transported in the TD direction at a transport speed of 60 mm / sec, and thickness measurements were performed at 0.5 mm intervals. First, the average thickness measured in the transport direction for each sample piece was determined. Then, the average thickness value of each of the five sample pieces was used as thickness data, and the average value was calculated as the thickness (μm) from the thickness data at those five points. In addition, the standard deviation was calculated as the thickness standard deviation (μm) from the thickness data at the five points, and the thickness variation coefficient (%) was calculated using the following formula. Thickness variation coefficient = thickness standard deviation / average thickness × 100

[0107] Reference Example 1 A reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser was charged with 1,034.99 g of 6-hydroxy-2-naphthoic acid (HNA; 5.5 mol), 83.07 g of terephthalic acid (TPA; 0.5 mol), 378.33 g of 2,6-naphthalenedicarboxylic acid (NDCA; 1.75 mol), 272.52 g of hydroquinone (HQ; 2.475 mol, used in an excess of 0.225 mol), 1,226.87 g of acetic anhydride (11.9 mol), and 0.17 g of 1-methylimidazole as a catalyst. After stirring for 15 minutes at room temperature under a nitrogen atmosphere, the mixture was heated with stirring and maintained at 145°C for 1 hour. Next, the mixture was heated from 145°C to 310°C over 3 hours and 30 minutes while distilling off the by-product acetic acid and unreacted acetic anhydride. The mixture was kept at 310° C. for 3 hours, then cooled to room temperature, and pulverized in a pulverizer to obtain a powder of a thermoplastic liquid crystal polymer.

[0108] The obtained powder was heated in a heating atmosphere. The temperature was raised from 25°C to 250°C over 1 hour, and then from 250°C to 315°C over 5 hours. The temperature was then held at 315°C, and the endothermic peak temperatures were 320.5°C and 340.5°C at a shear rate of 1000 s －１ The solid-state polymerization was carried out until the melt viscosity of the solid-state polymer reached 54 Pa s. Thereafter, the solid-state polymerized powder was cooled, and the cooled powder was granulated at 340 ° C. using a twin-screw kneading extruder to obtain pellets of thermoplastic liquid crystal polymer A.

[0109] Reference Example 2: 20.19 g of 6-hydroxy-2-naphthoic acid (HNA; 107.3 mmol), 7.73 g of 2,6-naphthalenedicarboxylic acid (NDCA; 35.8 mmol), 1.97 g of hydroquinone (HQ; 17.9 mmol), 3.33 g of 4,4'-dihydroxybiphenyl (BP; 17.9 mmol), 20.08 g of acetic anhydride (196.7 mmol), and 3.77 mg of potassium acetate as a catalyst were placed in a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. The mixture was heated from room temperature with stirring under a nitrogen atmosphere and maintained at 160°C for approximately 2 hours. The mixture was then heated and maintained at 280°C for 0.5 hours, 320°C for 1 hour, and 360°C for 1 hour. Next, a reduced pressure treatment (100 Pa) was performed (30 to 120 minutes) until the foaming was confirmed to have ceased, and then the mixture was substituted with nitrogen, cooled to room temperature, and pulverized in a pulverizer to obtain a powder of thermoplastic liquid crystal polymer. The powder after cooling had endothermic peak temperatures of 291.1 ° C. and 311.1 ° C. at a shear rate of 1000 s －１ The cooled powder was granulated at 315° C. using a twin-screw kneading extruder to obtain pellets of thermoplastic liquid crystal polymer B.

[0110] (Reference Example 3) 660.5 g of 6-hydroxy-2-naphthoic acid (HNA; 3.51 mol), 248.3 g of terephthalic acid (TPA; 1.49 mol), 14.3 g of hydroquinone (HQ; 0.13 mol), and 254.2 g of 4,4'-dihydroxybiphenyl (BP; 1.37 mol) were charged into a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, and 1.03 moles of acetic anhydride relative to the total amount (mol) of hydroxyl groups in the monomers was further charged. The mixture was heated from room temperature to 150°C over 1 hour with stirring under a nitrogen atmosphere, and then maintained at 150°C for 1 hour. Next, the mixture was heated to 350°C over 7 hours while distilling off the by-produced acetic acid, and then the pressure was reduced to 1333 Pa over 90 minutes. The polymerization reaction was terminated when a predetermined torque was reached, and the mixture was cooled to room temperature and pulverized in a pulverizer to obtain a powder of a thermoplastic liquid crystal polymer.

[0111] The obtained powder was heated in a heated atmosphere. The temperature was increased from 25°C to 250°C over 1 hour, and then increased from 250°C to 325°C over 2 hours. The temperature was then maintained at 325°C, and the endothermic peak temperatures were increased at a shear rate of 1000 s －１ The solid-state polymerization was carried out until the melt viscosity reached 55 Pa·s. The cooled powder was granulated at 360° C. using a twin-screw kneading extruder to obtain pellets of thermoplastic liquid crystal polymer C.

[0112] (Reference Example 4) A thermoplastic liquid crystal polymer ("A920RX" manufactured by Polyplastics Co., Ltd.; HBA / HNA = 73 / 27 (mol)) was heated from 25°C to 240°C over 1 hour. The temperature was then maintained at 240°C, and the endothermic peak temperature was 295.0°C. The shear rate at 315.0°C was 1000 s －１ The solid-state polymerization was carried out until the melt viscosity of the powder reached 53 Pa·s. The cooled powder was granulated at 315° C. using a twin-screw kneading extruder to obtain pellets of thermoplastic liquid crystal polymer D.

[0113] The following additive materials were used: Silica particles A ("Surface-treated Adma Fine Silica SC2500-SQ" manufactured by Admatechs Co., Ltd., median diameter 0.5 μm) Silica particles B (manufactured by Admatechs Co., Ltd., median diameter 0.3 μm) Polyphenylene ether (PPE; "Zylon S201A" manufactured by Asahi Kasei Corporation) Amorphous polyarylate (PAR; "U-100" manufactured by Unitika Ltd.)

[0114] (Example 1) 90.9 wt% of the thermoplastic liquid crystal polymer A obtained in Reference Example 1 and 9.1 wt% of silica particles A were melt-kneaded using a twin-screw kneading extruder at a cylinder setting temperature of 330 ° C. to prepare a resin composition. The analysis results of the obtained resin composition are shown in Table 7.

[0115] The resin composition was melt-extruded through an annular inflation die (die diameter 46.0 mm, die slit spacing 900 μm) at a draw ratio of 2.0 and a blow ratio of 4.2 to produce a film. The analytical results of the obtained film are shown in Table 7.

[0116] (Examples 2 to 9, Comparative Examples 1 to 5) Resin compositions and films were prepared in the same manner as in Example 1, except that each component was used in the weight ratio shown in Table 7. Table 7 shows the analysis results of the obtained resin compositions and films.

[0117]

[0118] As shown in Table 7, the resin compositions of Examples 1 to 9 had a dielectric loss tangent and a complex viscosity η ＊ Since the rate of decrease is within a specific range, the film obtained by molding such a resin composition can have a small coefficient of variation in thickness.

[0119] On the other hand, in Comparative Examples 1 and 2, the thermoplastic liquid crystal polymers had low dielectric loss tangents at 5 GHz, but the complex viscosities η ＊ Since the rate of decrease in thickness is high, the film obtained by molding such a thermoplastic liquid crystal polymer has a large coefficient of variation in thickness, and unevenness in film thickness occurs as an appearance defect.

[0120] The resin compositions of Comparative Examples 3 and 5 had low dielectric loss tangents at 5 GHz, but had low complex viscosities η ＊ Since the rate of decrease in thickness is high, the film obtained by molding such a resin composition has a large coefficient of variation in thickness, and unevenness in film thickness occurs as an appearance defect.

[0121] The resin composition of Comparative Example 4 had a complex viscosity η ＊ Since the rate of decrease in thickness is low, the film obtained by molding this has a small coefficient of variation in thickness, but since the dielectric loss tangent at 5 GHz is high, the dielectric properties in the high frequency range required for various circuit boards are insufficient.

[0122] The resin composition of the present invention has a low dielectric loss tangent in the high frequency band and can be molded into a film with reduced film thickness unevenness. Therefore, the film obtained by molding the resin composition can be suitably used as a high frequency circuit board material in the fields of electricity and electronics, office equipment and precision instruments, power semiconductors, etc.

[0123] While the preferred embodiments of the present invention have been described above, those skilled in the art will readily recognize various changes and modifications within the scope of the present invention, which are obvious from the description of the present invention. Therefore, such changes and modifications are to be interpreted as falling within the scope of the invention as defined by the claims.

Claims

1. A resin composition containing a thermoplastic liquid crystal polymer, which has a dielectric loss tangent of 0.0015 or less at 5 GHz, and which is measured using a rotational rheometer under the following measurement conditions at a frequency of 1 rad / s for 12 minutes, and then the complex viscosity η 7 minutes after switching to a frequency of 100 rad / s. ＊ The resin composition has a decrease rate of 20% or less. (Measurement conditions) Parallel plate measurement Gap distance: 0.9 mm Plate diameter: 25 mm Measurement temperature: Endothermic peak temperature Tm derived from a thermoplastic liquid crystal polymer measured using a differential scanning calorimeter １ +20°C Distortion: 3.0% Soak time at frequencies of 1 rad / s and 100 rad / s: 0.0 seconds Sampling interval at frequency of 100 rad / s: 5.0 seconds / pt Preheat time: 5 minutes 2. The resin composition according to claim 1, wherein the capillary rheometer is used to measure the temperature of the endothermic peak at a capillary diameter of 1.0 mm, a capillary length of 20 mm, and the endothermic peak temperature Tm １ +20°C, shear rate 1000 sec －１ and a melt viscosity measured under conditions of a preheating time of 5 minutes of 30 to 120 Pa·s.

3. The resin composition according to claim 1, wherein the capillary rheometer is used to measure the endothermic peak temperature Tm, the capillary diameter being 1.0 mm, the capillary length being 20 mm, １ +20°C, shear rate 1000 sec －１ The resin composition has a melt tension of 0.002 N or more when pulled at a take-up speed of 30 m / min under conditions of a pre-heating time of 5 minutes, a distance from the capillary outlet to the center position of a tension pulley of 200 mm.

4. The resin composition according to claim 1, wherein the endothermic peak temperature Tm during the first heating cycle is measured by repeating a heating and cooling cycle under the following heating and cooling conditions using a differential scanning calorimeter. １ and the endothermic peak temperature Tm during the sixth heating ６ Difference Tm １ -Tm ６ A resin composition having a temperature of 12° C. or less. (Temperature increase / decrease conditions) Temperature increase conditions: increase temperature from 25° C. to 400° C. at a rate of 20° C. / min, and hold for 2 minutes after reaching 400° C. Temperature decrease conditions: decrease temperature from 400° C. to 25° C. at a rate of 20° C. / min, and hold for 2 minutes after reaching 25° C.

5. The resin composition according to claim 1, wherein the endothermic peak temperature Tm is measured by using a capillary rheometer with a capillary diameter of 1.0 mm, a capillary length of 20 mm, and １ +20°C, shear rate 1000 sec －１ a melt viscosity measured under conditions of a pre-heating time of 5 minutes is designated as X (Pa s), and thereafter, after leaving the composition to stand in a barrel for 30 minutes at the same temperature, a melt viscosity measured under conditions of the same temperature and shear rate is designated as Y (Pa s), and the ratio Y / X of these two is 1.30 or less.

6. The resin composition according to claim 1, wherein the repeating units represented by the following formula (1) account for 0 to 25 mol %, the repeating units represented by the following formula (2) account for 25 to 90 mol %, the repeating units represented by the following formula (3) account for 0.1 to 40 mol %, and the repeating units represented by the following formula (4) account for 0.1 to 40 mol %, based on the total amount of all repeating units in the thermoplastic liquid crystal polymer. １ -CO- (1) -O-Ar ２ -CO- (2) -CO-Ar ３ -CO- (3) -O-Ar ４ -O- (4) (wherein, Ar １ is a 1,4-phenylene group, Ar ２ is a 2,6-naphthylene group, and Ar ３ is at least one selected from the group consisting of a 1,4-phenylene group, a 1,3-phenylene group, and a 2,6-naphthylene group, and Ar ４ is at least one selected from the group consisting of a 1,4-phenylene group, a 1,3-phenylene group, and a 4,4′-biphenylylene group, and Ar １ , Ar ２ , Ar ３ and Ar ４ The hydrogen atoms of the aromatic ring are each independently represented by C １－３ may be substituted with at least one selected from the group consisting of an alkyl group, a halogen atom, and a phenyl group) 7. A resin composition according to claim 6, wherein the total amount of repeating units containing 2,6-naphthylene groups in the thermoplastic liquid crystal polymer is 40 mol % or more relative to the total amount of all repeating units.

8. The resin composition according to claim 1, comprising particulate matter.

9. The resin composition according to claim 1, further comprising an additive material, the additive material being at least one selected from the group consisting of thermoplastic resins, thermosetting resins, inorganic compounds and liquid crystal oligomers.

10. A resin composition according to claim 9, comprising as the thermoplastic resin at least one selected from the group consisting of amorphous polyarylate-based resins, polyphenylene ether-based resins, polyphenylene sulfide-based resins, polyetherimide-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyetheretherketone-based resins, and fluorine-based resins.

11. The resin composition according to claim 9, comprising as said inorganic compound at least one selected from the group consisting of silica and titanium oxide.

12. The resin composition according to claim 9, which contains two or more types of inorganic particles having different median sizes.

13. The resin composition according to claim 9, comprising two or more of the additive materials.

14. The resin composition according to claim 9, wherein the weight ratio of the thermoplastic liquid crystal polymer to the additive material (thermoplastic liquid crystal polymer / additive material) is in the range of 63.0 / 37.0 to 94.9 / 5.

1.

15. A film comprising the resin composition according to any one of claims 1 to 14.

16. The film according to claim 15, having a thickness of 5 to 200 μm.

17. The film according to claim 15, which has a coefficient of variation in thickness in the width direction of the film as measured by a continuous thickness meter of 1.90% or less.

18. A metal-clad laminate comprising the film according to claim 15 and a metal layer bonded to at least one surface of the film.

19. A circuit board comprising at least a conductor layer and an insulating layer containing the resin composition according to any one of claims 1 to 14.