Resin composition and molded body

Abstract

The present invention pertains to a resin composition and a molded body containing the resin composition. The resin composition contains: a polyimide resin (A) which includes a repeat structural unit represented by formula (1) and a repeat structural unit represented by formula (2) and in which the content ratio of the repeat structural unit represented by formula (1) with respect to the total of the repeat structural unit represented by formula (1) and the repeat structural unit represented by formula (2) is 20-70 mol%; and a resin represented by a prescribed formula (5) or an acid modified product thereof (B). The ratio [(B) / {(A)+(B)}] of the contained mass of the component (B) with respect to the total contained mass of the component (A) and the component (B) is higher than 0.50. (R1 represents a divalent group having 6-22 carbon atoms and including at least one alicyclic hydrocarbon structure. R2 represents a divalent chain-like aliphatic group having 5-16 carbon atoms. X1 and X2 each independently represent a tetravalent group having 6-22 carbon atoms and including at least one aromatic ring.)

Description

Resin composition and molded article

[0001] The present invention relates to a resin composition and a molded article.

[0002] Polyimide resins are useful engineering plastics with high thermal stability, strength, and solvent resistance due to their molecular chain rigidity, resonance stabilization, and strong chemical bonds, and are used in a wide range of fields. While polyimide resins have high heat resistance, they lack thermoplasticity and have the drawback of poor moldability. However, in recent years, thermoplastic polyimide resins have been reported. Thermoplastic polyimide resins not only have the inherent heat resistance of polyimide resins, but also have excellent moldability. Therefore, thermoplastic polyimide resins can be used to mold products used in harsh environments, something that general-purpose thermoplastic resins such as nylon and polyester could not.

[0003] One known molecular design technique for imparting thermoplasticity to polyimide resins is to incorporate flexible structures, such as aliphatic structures, into the main chain. While aliphatic structures have the advantages of relatively easily imparting thermoplasticity to polyimides and easily exhibiting low dielectric properties due to their bulkiness, they have the drawback of being less resistant to oxidation than aromatic structures, thereby reducing the inherently high flame retardancy of polyimides. Therefore, in order to apply such thermoplastic polyimide resins to applications requiring high flame retardancy, efforts have been made to improve flame retardancy by adding flame retardants. For example, Patent Document 1 discloses that a resin composition containing a polyimide resin of a specific structure and a metal phosphinate flame retardant exhibits excellent moldability, high flame retardancy, and a good appearance.

[0004] A method of modifying a resin by using two or more resin components instead of using additives such as flame retardants is also known. For example, Patent Document 2 discloses that a resin composition containing predetermined polyimide resin particles and at least one resin selected from the group consisting of thermoplastic resins and thermosetting resins can improve various properties such as heat resistance and mechanical properties while maintaining the light weight inherent to the resin.

[0005] International Publication No. 2019 / 220968 International Publication No. 2021 / 100716

[0006] The technology disclosed in Patent Document 2 is a technology for improving heat resistance, mechanical properties, etc. by incorporating a polyimide resin into a thermoplastic resin or a thermosetting resin while maintaining the particulate state without thermally melting it, but it does not improve the flame retardancy of the resin composition. An object of the present invention is to provide a resin composition and a molded article that can exhibit high flame retardancy even when a small amount of flame retardant is used or no flame retardant is used.

[0007] The present inventors have found that the above-mentioned problems can be solved by a resin composition containing a polyimide resin formed by combining specific different polyimide structural units in a specific ratio, and an aromatic resin having a specific structure, in a predetermined ratio. Specifically, the present invention relates to the following: [1] A resin composition comprising: a polyimide resin (A) containing repeating structural units represented by the following formula (1) and repeating structural units represented by the following formula (2), wherein the content of the repeating structural units of formula (1) relative to the total content of the repeating structural units of formula (1) and formula (2) is 20 to 70 mol %, and a resin (B) represented by the following formula (5) or an acid-modified product thereof, wherein the ratio of the mass content of component (B) to the total mass content of component (A) and component (B), [(B) / {(A)+(B)}], is greater than 0.50. (R １ is a divalent group having 6 to 22 carbon atoms and containing at least one alicyclic hydrocarbon structure. ２ is a divalent chain aliphatic group having 5 to 16 carbon atoms. １ and X ２ are each independently a tetravalent group containing at least one aromatic ring and having 6 to 22 carbon atoms. (R ５１ ~R ５５ , and R ６１ ~R ６４ are each independently a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 4 carbon atoms, and R ６５is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n is the number of repeating structural units and is a number of 10 or more.) [2] The resin composition according to the above [1], wherein the total content of the component (A) and the component (B) in the resin composition is 50% by mass or more. [3] The resin composition according to the above [1] or [2], wherein the intrinsic viscosity of the component (B) measured in chloroform at 30°C is 0.20 to 0.60 dL / g. [4] The resin composition according to any one of the above [1] to [3], wherein the resin composition is obtained by melt-kneading at a temperature exceeding the melting point of the component (A). [5] The resin composition according to any one of the above [1] to [4], wherein pellets made of the resin composition have a microphase-separated structure. [6] A molded article comprising the resin composition according to any one of the above [1] to [5]. [7] The molded article according to the above [6], wherein the molded article is an injection-molded article. [8] The molded article according to [6] or [7] above, wherein the molded article having a thickness of 4 mm has an oxygen index of 28 or more, as measured in accordance with JIS K 7201:1995.

[0008] According to the present invention, it is possible to provide a resin composition and a molded article that can exhibit high flame retardancy even when a small amount of a flame retardant is used or no flame retardant is used at all.

[0009] 1 is a schematic diagram showing a method for preparing a sample (ultrathin section) used for observation with a field emission scanning transmission electron microscope (FE-STEM). 2 is a micrograph of a cross section of the resin composition (pellet) of Example 1, cut in a direction perpendicular to the machine direction (MD), observed with an FE-STEM. 3 is a schematic diagram for explaining a method for preparing a test piece used for evaluating the adhesion between a film and a copper foil. 4 is a schematic diagram for explaining a method for evaluating the adhesion between a film and a copper foil, and the tensile adhesive strength.

[0010] [Resin Composition] The resin composition of the present invention contains a polyimide resin (A) that contains a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), wherein the content ratio of the repeating structural unit of formula (1) to the total of the repeating structural units of formula (1) and formula (2) is 20 to 70 mol %, and a resin (B) that is represented by the following formula (5) or an acid-modified product thereof, wherein the ratio of the content of component (B) to the total content of component (A) and component (B) [(B) / {(A)+(B)}] is greater than 0.50. (R １ is a divalent group having 6 to 22 carbon atoms and containing at least one alicyclic hydrocarbon structure. ２ is a divalent chain aliphatic group having 5 to 16 carbon atoms. １ and X ２ are each independently a tetravalent group containing at least one aromatic ring and having 6 to 22 carbon atoms. (R ５１ ~R ５５ , and R ６１ ~R ６４ are each independently a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 4 carbon atoms, and R ６５ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and n is the number of repeating structural units and is a number of 10 or more.

[0011] The resin composition of the present invention contains a polyimide resin (A) obtained by combining specific different polyimide structural units in the above-mentioned specific ratio, and a resin represented by the formula (5) or an acid-modified product thereof (B) in a predetermined ratio, thereby exhibiting high flame retardancy even with a small amount of flame retardant or no flame retardant being used. The reason for the above-mentioned effect of the present invention is unclear, but it is thought to be as follows. The resin composition of the present invention is a resin composition in which the mass ratio [(B) / {(A)+(B)}] is greater than 0.50 and the content of aromatic rings is high. Therefore, for example, when a molded article made from the resin composition is subjected to a combustion test, char formation is promoted on the surface of the molded article, making it difficult to burn. Furthermore, as described below, it is thought that components (A) and (B) form a microphase-separated structure in the resin composition or molded article, and that at the phase-separated interface between components (A) and (B), the aromatic rings in component (A) and the aromatic structures in component (B) partially form charge-transfer complexes, thereby thermally stabilizing the structure.

[0012] Furthermore, by containing component (A) and component (B), the resin composition of the present invention can achieve an extremely low dielectric constant and dielectric dissipation factor (hereinafter, these will also be collectively referred to as "low dielectric properties") for a resin material, and further, the resin composition also has good adhesion to metal foils such as copper foils.

[0013] <Polyimide Resin (A)> The polyimide resin (A) used in the present invention contains a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), and the content ratio of the repeating structural unit of formula (1) to the total of the repeating structural units of formula (1) and formula (2) is 20 to 70 mol %. (R １ is a divalent group having 6 to 22 carbon atoms and containing at least one alicyclic hydrocarbon structure. ２ is a divalent chain aliphatic group having 5 to 16 carbon atoms. １ and X ２ are each independently a tetravalent group containing at least one aromatic ring and having 6 to 22 carbon atoms.

[0014] The polyimide resin (A) used in the present invention is a thermoplastic resin, and is preferably in the form of powder or pellets. Thermoplastic polyimide resins are distinguished from polyimide resins that do not have a glass transition temperature (Tg) or that decompose at a temperature lower than the glass transition temperature, and are formed by molding a polyimide precursor such as polyamic acid and then closing the imide ring.

[0015] The repeating structural unit of formula (1) is described in detail below. １ is a divalent group having 6 to 22 carbon atoms and containing at least one alicyclic hydrocarbon structure. Here, the alicyclic hydrocarbon structure refers to a ring derived from an alicyclic hydrocarbon compound, and the alicyclic hydrocarbon compound may be saturated or unsaturated, and may be monocyclic or polycyclic. Examples of alicyclic hydrocarbon structures include, but are not limited to, cycloalkane rings such as a cyclohexane ring, cycloalkene rings such as cyclohexene, bicycloalkane rings such as norbornane, and bicycloalkene rings such as norbornene. Among these, a cycloalkane ring is preferred, a cycloalkane ring having 4 to 7 carbon atoms is more preferred, and a cyclohexane ring is even more preferred. R １ has 6 to 22 carbon atoms, preferably 8 to 17. １ contains at least one alicyclic hydrocarbon structure, preferably 1 to 3.

[0016] R １ is preferably a divalent group represented by the following formula (R1-1) or (R1-2): (m １１ and m １２ are each independently an integer of 0 to 2, preferably 0 or 1. １３ ~m １５ are each independently an integer of 0 to 2, preferably 0 or 1.

[0017] R １ is particularly preferably a divalent group represented by the following formula (R1-3): In the divalent group represented by the above formula (R1-3), the positional relationship of the two methylene groups with respect to the cyclohexane ring may be either cis or trans, and the ratio of cis to trans may be any value.

[0018] X １ is a tetravalent group having 6 to 22 carbon atoms and containing at least one aromatic ring. The aromatic ring may be a single ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a tetracene ring, but are not limited to these. Among these, a benzene ring and a naphthalene ring are preferred, and a benzene ring is more preferred. X １ has 6 to 22 carbon atoms, preferably 6 to 18. １ contains at least one aromatic ring, preferably 1 to 3.

[0019] X １ is preferably a tetravalent group represented by any one of the following formulae (X-1) to (X-4). (R １１ ~R １８ are each independently an alkyl group having 1 to 4 carbon atoms. １１ ~p １３ are each independently an integer of 0 to 2, preferably 0. １４ , p １５ , p １６ and p １８ are each independently an integer of 0 to 3, preferably 0. １７ is an integer of 0 to 4, preferably 0. １１ ~L １３ are each independently a single bond, an ether group, a carbonyl group, or an alkylene group having 1 to 4 carbon atoms. １ is a tetravalent group having 6 to 22 carbon atoms and containing at least one aromatic ring, and therefore, R １２ , R １３ , p １２ and p １３ is selected so that the number of carbon atoms of the tetravalent group represented by formula (X-2) is in the range of 10 to 22. Similarly, L in formula (X-3) １１ , R １４ , R１５ , p １４ and p １５ is selected so that the number of carbon atoms of the tetravalent group represented by formula (X-3) is in the range of 12 to 22, and L in formula (X-4) １２ , L １３ , R １６ , R １７ , R １８ , p １６ , p １７ and p １８ is selected so that the number of carbon atoms in the tetravalent group represented by formula (X-4) falls within the range of 18 to 22.

[0020] X １ is particularly preferably a tetravalent group represented by the following formula (X-5) or (X-6).

[0021] Next, the repeating structural unit of formula (2) will be described in detail below. ２ is a divalent chain aliphatic group having 5 to 16 carbon atoms, preferably 6 to 14 carbon atoms, more preferably 7 to 12 carbon atoms, and even more preferably 8 to 10 carbon atoms. Here, the chain aliphatic group means a group derived from a chain aliphatic compound, and the chain aliphatic compound may be saturated or unsaturated, linear or branched, and may contain a heteroatom such as an oxygen atom. ２ is preferably an alkylene group having 5 to 16 carbon atoms, more preferably an alkylene group having 6 to 14 carbon atoms, even more preferably an alkylene group having 7 to 12 carbon atoms, and among these, an alkylene group having 8 to 10 carbon atoms is preferred. The alkylene group may be a linear alkylene group or a branched alkylene group, but is preferably a linear alkylene group. ２ is preferably at least one selected from the group consisting of an octamethylene group and a decamethylene group, and particularly preferably an octamethylene group.

[0022] Also, R ２Another preferred embodiment of the group R2-1 is a divalent chain aliphatic group containing an ether group and having 5 to 16 carbon atoms. The number of carbon atoms is preferably 6 to 14, more preferably 7 to 12, and even more preferably 8 to 10. Among these, a divalent group represented by the following formula (R2-1) or (R2-2) is preferred. (m ２１ and m ２２ are each independently an integer of 1 to 15, preferably 1 to 13, more preferably 1 to 11, and even more preferably 1 to 9. ２３ ~m ２５ are each independently an integer of 1 to 14, preferably 1 to 12, more preferably 1 to 10, and even more preferably 1 to 8. ２ is a divalent chain aliphatic group having 5 to 16 carbon atoms (preferably 6 to 14 carbon atoms, more preferably 7 to 12 carbon atoms, and even more preferably 8 to 10 carbon atoms), and therefore, m in formula (R2-1) ２１ and m ２２ is selected so that the carbon number of the divalent group represented by formula (R2-1) is in the range of 5 to 16 (preferably 6 to 14 carbon atoms, more preferably 7 to 12 carbon atoms, and even more preferably 8 to 10 carbon atoms). ２１ +m ２２ is 5 to 16 (preferably 6 to 14, more preferably 7 to 12, and even more preferably 8 to 10). ２３ ~m ２５ is selected so that the carbon number of the divalent group represented by formula (R2-2) is in the range of 5 to 16 (preferably 6 to 14 carbon atoms, more preferably 7 to 12 carbon atoms, and even more preferably 8 to 10 carbon atoms). ２３ +m ２４ +m ２５ has 5 to 16 carbon atoms (preferably 6 to 14 carbon atoms, more preferably 7 to 12 carbon atoms, and even more preferably 8 to 10 carbon atoms).

[0023] X ２ is X in formula (1). １ The definitions and preferred embodiments are the same as above.

[0024] The content ratio of the repeating structural unit of formula (1) relative to the total of the repeating structural units of formula (1) and formula (2) is 20 to 70 mol%. When the content ratio of the repeating structural unit of formula (1) is within the above range, the polyimide resin can be sufficiently crystallized even in a typical injection molding cycle. If the content ratio is less than 20 mol%, moldability decreases, and if it exceeds 70 mol%, crystallinity decreases, resulting in decreased heat resistance. From the viewpoint of achieving high crystallinity, the content ratio of the repeating structural unit of formula (1) relative to the total of the repeating structural units of formula (1) and formula (2) is preferably 65 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less. In particular, the content ratio of the repeating structural unit of formula (1) relative to the total of the repeating structural units of formula (1) and formula (2) is preferably 20 mol% or more but less than 40 mol%. Within this range, the crystallinity of the polyimide resin (A) is increased, resulting in a resin composition with even better heat resistance. From the viewpoint of moldability, the content ratio is preferably 25 mol% or more, more preferably 30 mol% or more, and even more preferably 32 mol% or more, and from the viewpoint of expressing high crystallinity, it is even more preferably 35 mol% or less.

[0025] The total content of the repeating structural units of formula (1) and formula (2) relative to all repeating structural units constituting the polyimide resin (A) is preferably 50 to 100 mol %, more preferably 75 to 100 mol %, even more preferably 80 to 100 mol %, and still more preferably 85 to 100 mol %.

[0026] The polyimide resin (A) may further contain a repeating structural unit of the following formula (3). In this case, the content ratio of the repeating structural unit of formula (3) relative to the total of the repeating structural units of formula (1) and formula (2) is preferably 25 mol% or less. On the other hand, there is no particular lower limit, as long as it is greater than 0 mol%. From the viewpoint of improving heat resistance, the content ratio is preferably 5 mol% or more, more preferably 10 mol% or more, while from the viewpoint of maintaining crystallinity, the content ratio is preferably 20 mol% or less, more preferably 15 mol% or less. (R ３ is a divalent group having 6 to 22 carbon atoms and containing at least one aromatic ring. ３ is a tetravalent group having 6 to 22 carbon atoms and containing at least one aromatic ring.

[0027] R ３ is a divalent group having 6 to 22 carbon atoms and containing at least one aromatic ring. The aromatic ring may be a single ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, and a tetracene ring, but are not limited to these. Among these, a benzene ring and a naphthalene ring are preferred, and a benzene ring is more preferred. R ３ has 6 to 22 carbon atoms, preferably 6 to 18. ３ contains at least one aromatic ring, preferably 1 to 3. The aromatic ring may have a monovalent or divalent electron-withdrawing group bonded thereto. Examples of the monovalent electron-withdrawing group include a nitro group, a cyano group, a p-toluenesulfonyl group, halogen, a halogenated alkyl group, a phenyl group, and an acyl group. Examples of the divalent electron-withdrawing group include a fluorinated alkylene group (e.g., -C(CF ３ ) ２ -, - (CF ２ ) ｐ In addition to halogenated alkylene groups such as - (where p is an integer from 1 to 10), -CO-, -SO ２ -, -SO-, -CONH-, -COO- and the like.

[0028] R ３ is preferably a divalent group represented by the following formula (R3-1) or (R3-2). (m ３１ and m ３２ are each independently an integer of 0 to 2, preferably 0 or 1. ３３ and m ３４ are each independently an integer of 0 to 2, preferably 0 or 1. ２１ , R ２２ , and R ２３ are each independently an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or an alkynyl group having 2 to 4 carbon atoms. ２１ , p２２ and p ２３ is an integer of 0 to 4, preferably 0. ２１ is a single bond, an ether group, a carbonyl group, or an alkylene group having 1 to 4 carbon atoms. ３ is a divalent group having 6 to 22 carbon atoms and containing at least one aromatic ring, and therefore, m ３１ , m ３２ , R ２１ and p ２１ is selected so that the number of carbon atoms of the divalent group represented by formula (R3-1) is in the range of 6 to 22. Similarly, L in formula (R3-2) ２１ , m ３３ , m ３４ , R ２２ , R ２３ , p ２２ and p ２３ is selected so that the number of carbon atoms in the divalent group represented by formula (R3-2) falls within the range of 12 to 22.

[0029] X ３ is X in formula (1). １ The definitions and preferred embodiments are the same as above.

[0030] The polyimide resin (A) may further contain a repeating structural unit represented by the following formula (4). (R ４ Ha-SO ２ - or -Si(R ｘ ) (R ｙ ) is a divalent group containing O—, and R ｘ and R ｙ each independently represents a chain aliphatic group having 1 to 3 carbon atoms or a phenyl group. ４ is a tetravalent group having 6 to 22 carbon atoms and containing at least one aromatic ring. ４ is X in formula (1). １ The definitions and preferred embodiments are the same as above.

[0031] The terminal structure of the polyimide resin (A) is not particularly limited, but it is preferable that the polyimide resin (A) has a chain aliphatic group having 5 to 14 carbon atoms at the terminal. The chain aliphatic group may be saturated or unsaturated, and may be linear or branched. When the polyimide resin (A) has the above-mentioned specific group at the terminal, a resin composition with excellent heat aging resistance can be obtained. Examples of saturated chain aliphatic groups having 5 to 14 carbon atoms include an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, a lauryl group, an n-tridecyl group, an n-tetradecyl group, an isopentyl group, a neopentyl group, a 2-methylpentyl group, a 2-methylhexyl group, a 2-ethylpentyl group, a 3-ethylpentyl group, an isooctyl group, a 2-ethylhexyl group, a 3-ethylhexyl group, an isononyl group, a 2-ethyloctyl group, an isodecyl group, an isododecyl group, an isotridecyl group, and an isotetradecyl group. Examples of unsaturated chain aliphatic groups having 5 to 14 carbon atoms include 1-pentenyl, 2-pentenyl, 1-hexenyl, 2-hexenyl, 1-heptenyl, 2-heptenyl, 1-octenyl, 2-octenyl, nonenyl, decenyl, dodecenyl, tridecenyl, and tetradecenyl groups. Among these, the chain aliphatic groups are preferably saturated chain aliphatic groups, and more preferably saturated linear chain aliphatic groups. Furthermore, from the viewpoint of obtaining heat aging resistance, the chain aliphatic groups preferably have 6 or more carbon atoms, more preferably 7 or more carbon atoms, and even more preferably 8 or more carbon atoms, and preferably have 12 or less carbon atoms, more preferably 10 or less carbon atoms, and even more preferably have 9 or less carbon atoms. The chain aliphatic groups may be of one type, or two or more types. The chain aliphatic group is particularly preferably at least one selected from the group consisting of an n-octyl group, an isooctyl group, a 2-ethylhexyl group, an n-nonyl group, an isononyl group, an n-decyl group, and an isodecyl group, further preferably at least one selected from the group consisting of an n-octyl group, an isooctyl group, a 2-ethylhexyl group, an n-nonyl group, and an isononyl group, and most preferably at least one selected from the group consisting of an n-octyl group, an isooctyl group, and a 2-ethylhexyl group.From the viewpoint of heat aging resistance, the polyimide resin (A) preferably has, at its terminals, only chain aliphatic groups having 5 to 14 carbon atoms in addition to terminal amino groups and terminal carboxy groups. When a group other than the above is present at its terminals, the content thereof is preferably 10 mol % or less, more preferably 5 mol % or less, based on the chain aliphatic groups having 5 to 14 carbon atoms.

[0032] From the viewpoint of exhibiting excellent heat aging resistance, the content of the chain aliphatic groups having 5 to 14 carbon atoms in the polyimide resin (A) is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, and even more preferably 0.2 mol% or more, based on 100 mol% of the total of all repeating structural units constituting the polyimide resin (A). Furthermore, in order to ensure a sufficient molecular weight and obtain good mechanical properties, the content of the chain aliphatic groups having 5 to 14 carbon atoms in the polyimide resin (A) is preferably 10 mol% or less, more preferably 6 mol% or less, and even more preferably 3.5 mol% or less, based on 100 mol% of the total of all repeating structural units constituting the polyimide resin (A). The content of the chain aliphatic groups having 5 to 14 carbon atoms in the polyimide resin (A) can be determined by depolymerizing the polyimide resin (A).

[0033] The polyimide resin (A) preferably has a melting point of 360°C or lower and a glass transition temperature of 150°C or higher. From the viewpoint of heat resistance, the melting point of the polyimide resin (A) is more preferably 280°C or higher, even more preferably 290°C or higher. From the viewpoint of exhibiting high moldability, the melting point is preferably 345°C or lower, more preferably 340°C or lower, even more preferably 335°C or lower. From the viewpoint of exhibiting high moldability, the glass transition temperature of the polyimide resin (A) is more preferably 160°C or higher, more preferably 170°C or higher. From the viewpoint of exhibiting high moldability, the glass transition temperature is preferably 250°C or lower, more preferably 230°C or lower, even more preferably 200°C or lower. The melting point and glass transition temperature of the polyimide resin (A) can both be measured by a differential scanning calorimeter. Furthermore, from the viewpoint of improving crystallinity, heat resistance, mechanical strength, and chemical resistance, the polyimide resin (A) preferably has a heat value of 5.0 mJ / mg or more, more preferably 10.0 mJ / mg or more, and even more preferably 17.0 mJ / mg or more, of the heat value of the exothermic crystallization peak observed when the polyimide resin is melted and then cooled at a temperature decreasing rate of 20°C / min, as measured by a differential scanning calorimeter. The upper limit of the heat value of crystallization is not particularly limited, but is usually 45.0 mJ / mg or less. The melting point, glass transition temperature, and heat value of crystallization of the polyimide resin (A) can be specifically measured by the methods described in the Examples.

[0034] The logarithmic viscosity of a 0.5 mass % solution of polyimide resin (A) in concentrated sulfuric acid at 30°C is preferably in the range of 0.2 to 2.0 dL / g, more preferably 0.3 to 1.8 dL / g. If the logarithmic viscosity is 0.2 dL / g or higher, sufficient mechanical strength can be obtained when the resulting resin composition is molded into a molded article, and if it is 2.0 dL / g or lower, moldability and handleability are improved. The logarithmic viscosity μ can be calculated by measuring the flow times of concentrated sulfuric acid and the polyimide resin solution at 30°C using a Cannon-Fenske viscometer, and then using the following formula: μ=ln(ts / t ０ ) / C t ０ : Time during which concentrated sulfuric acid flows ts: Time during which polyimide resin solution flows C: 0.5 (g / dL)

[0035] The weight-average molecular weight Mw of the polyimide resin (A) is preferably in the range of 10,000 to 150,000, more preferably 15,000 to 100,000, even more preferably 20,000 to 80,000, still more preferably 30,000 to 70,000, and even more preferably 35,000 to 65,000. If the weight-average molecular weight Mw of the polyimide resin (A) is 10,000 or more, the mechanical strength of the resulting molded article will be good; if it is 40,000 or more, the stability of the mechanical strength will be good; and if it is 150,000 or less, the moldability will be good. The weight-average molecular weight Mw of the polyimide resin (A) can be measured by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) as a standard sample.

[0036] (Method for Producing Polyimide Resin (A)) The polyimide resin (A) can be produced by reacting a tetracarboxylic acid component with a diamine component. The tetracarboxylic acid component contains a tetracarboxylic acid and / or a derivative thereof having at least one aromatic ring, and the diamine component contains a diamine having at least one alicyclic hydrocarbon structure and a chain aliphatic diamine.

[0037] The tetracarboxylic acid containing at least one aromatic ring is preferably a compound in which four carboxy groups are directly bonded to the aromatic ring, and may contain an alkyl group in the structure. The tetracarboxylic acid preferably has 6 to 26 carbon atoms. Examples of the tetracarboxylic acid include pyromellitic acid, 2,3,5,6-toluenetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, and 1,4,5,8-naphthalenetetracarboxylic acid. Among these, pyromellitic acid is more preferred.

[0038] Examples of the derivative of a tetracarboxylic acid containing at least one aromatic ring include anhydrides or alkyl esters of tetracarboxylic acids containing at least one aromatic ring. The tetracarboxylic acid derivative preferably has 6 to 38 carbon atoms. Examples of the anhydrides of tetracarboxylic acids include pyromellitic acid monoanhydride, pyromellitic acid dianhydride, 2,3,5,6-toluenetetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, and 1,4,5,8-naphthalenetetracarboxylic acid dianhydride. Examples of alkyl esters of tetracarboxylic acids include dimethyl pyromellitic acid, diethyl pyromellitic acid, dipropyl pyromellitic acid, diisopropyl pyromellitic acid, dimethyl 2,3,5,6-toluenetetracarboxylate, dimethyl 3,3',4,4'-diphenylsulfonetetracarboxylate, dimethyl 3,3',4,4'-benzophenonetetracarboxylate, dimethyl 3,3',4,4'-biphenyltetracarboxylate, dimethyl 1,4,5,8-naphthalenetetracarboxylate, etc. In the alkyl esters of tetracarboxylic acids, the alkyl group preferably has 1 to 3 carbon atoms.

[0039] The tetracarboxylic acid and / or derivative thereof containing at least one aromatic ring may be at least one compound selected from the above, and may be used alone or in combination of two or more compounds.

[0040] The diamine containing at least one alicyclic hydrocarbon structure preferably has 6 to 22 carbon atoms, and examples thereof include 1,2-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis(2-methylcyclohexylamine), carvonediamine, limonenediamine, isophoronediamine, norbornanediamine, bis(aminomethyl)tricyclo[5.2.1.0] ... ２，６]decane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylpropane, etc. are preferred. These compounds may be used alone, or two or more compounds selected from these may be used in combination. Of these, 1,3-bis(aminomethyl)cyclohexane is preferably used. Note that diamines containing an alicyclic hydrocarbon structure generally have structural isomers, but the ratio of cis / trans isomers is not limited.

[0041] The chain aliphatic diamine may be linear or branched, and preferably has 5 to 16 carbon atoms, more preferably 6 to 14, and even more preferably 7 to 12. Furthermore, as long as the chain portion has 5 to 16 carbon atoms, it may contain an ether bond therebetween. Preferred examples of the chain aliphatic diamine include 1,5-pentamethylenediamine, 2-methylpentane-1,5-diamine, 3-methylpentane-1,5-diamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine, and 2,2'-(ethylenedioxy)bis(ethyleneamine). The chain aliphatic diamine may be used alone or in combination. Among these, chain aliphatic diamines having 8 to 10 carbon atoms are preferably used, and at least one selected from the group consisting of 1,8-octamethylenediamine and 1,10-decamethylenediamine is particularly preferably used.

[0042] In producing the polyimide resin (A), the molar ratio of the amount of the diamine containing at least one alicyclic hydrocarbon structure charged to the total amount of the diamine containing at least one alicyclic hydrocarbon structure and the chain aliphatic diamine is preferably 20 to 70 mol %. This molar ratio is preferably 25 mol % or more, more preferably 30 mol % or more, and even more preferably 32 mol % or more, and from the viewpoint of achieving high crystallinity, is preferably 60 mol % or less, more preferably 50 mol % or less, even more preferably less than 40 mol %, and even more preferably 35 mol % or less.

[0043] The diamine component may also contain a diamine containing at least one aromatic ring. The diamine containing at least one aromatic ring preferably has 6 to 22 carbon atoms, and examples thereof include ortho-xylylenediamine, meta-xylylenediamine, para-xylylenediamine, 1,2-diethynylbenzenediamine, 1,3-diethynylbenzenediamine, 1,4-diethynylbenzenediamine, 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-diaminobenzene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, α,α'-bis(4-aminophenyl)1,4-diisopropylbenzene, α,α'-bis(3-aminophenyl)-1,4-diisopropylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,6-diaminonaphthalene, and 1,5-diaminonaphthalene.

[0044] In the above, the molar ratio of the amount of the diamine containing at least one aromatic ring to the total amount of the diamine containing at least one alicyclic hydrocarbon structure and the chain aliphatic diamine is preferably 25 mol% or less. On the other hand, the lower limit is not particularly limited, as long as it is greater than 0 mol%. From the viewpoint of improving heat resistance, the molar ratio is preferably 5 mol% or more, more preferably 10 mol% or more, while from the viewpoint of maintaining crystallinity, the molar ratio is preferably 20 mol% or less, more preferably 15 mol% or less. Furthermore, from the viewpoint of reducing coloration of the polyimide resin (A), the molar ratio is preferably 12 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, and even more preferably 0 mol%.

[0045] When producing the polyimide resin (A), the ratio of the amount of the tetracarboxylic acid component to the amount of the diamine component charged is preferably 0.9 to 1.1 moles of the diamine component per mole of the tetracarboxylic acid component.

[0046] Furthermore, when producing the polyimide resin (A), a terminal-capping agent may be mixed in addition to the tetracarboxylic acid component and the diamine component. The terminal-capping agent is preferably at least one selected from the group consisting of monoamines and dicarboxylic acids. The amount of terminal-capping agent used may be any amount sufficient to introduce the desired amount of terminal groups into the polyimide resin (A), and is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.06 mol, and even more preferably 0.002 to 0.035 mol per mol of the tetracarboxylic acid and / or its derivative. Among these, monoamine terminal-capping agents are preferred. From the viewpoint of introducing the aforementioned linear aliphatic group having 5 to 14 carbon atoms to the terminal of the polyimide resin (A) to improve heat aging resistance, monoamines having a linear aliphatic group having 5 to 14 carbon atoms are more preferred, and monoamines having a saturated linear aliphatic group having 5 to 14 carbon atoms are even more preferred. The end-capping agent is particularly preferably at least one selected from the group consisting of n-octylamine, isooctylamine, 2-ethylhexylamine, n-nonylamine, isononylamine, n-decylamine, and isodecylamine, more preferably at least one selected from the group consisting of n-octylamine, isooctylamine, 2-ethylhexylamine, n-nonylamine, and isononylamine, and most preferably at least one selected from the group consisting of n-octylamine, isooctylamine, and 2-ethylhexylamine.

[0047] As a polymerization method for producing the polyimide resin (A), a known polymerization method can be applied, and the method described in WO 2016 / 147996 can be used.

[0048] <Resin Represented by Formula (5) or Acid-Modified Product Thereof (B)> The resin composition of the present invention contains a polyimide resin (A) and a resin represented by the following formula (5) or an acid-modified product thereof (B). (R ５１ ~R ５５ , and R ６１ ~R ６４ are each independently a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 4 carbon atoms, and R ６５is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and n is the number of repeating structural units and is a number of 10 or more.

[0049] In formula (5), R ５１ ~R ５５ , and R ６１ ~R ６５ The alkyl group having 1 to 4 carbon atoms in the formula (I) may be either linear or branched, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Among these, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group is preferred, and a methyl group is more preferred.

[0050] In formula (5), R ５１ , R ５３ , R ６１ , and R ６３ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. ５２ , R ５４ , R ６２ , and R ６４ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a methyl group. ６５ is preferably a hydrogen atom.

[0051] In formula (5), n is a number of 10 or more, and more preferably 20 or more.

[0052] The resin represented by the formula (5) is preferably poly(2,6-dimethyl-1,4-phenylene ether), which is a resin represented by the following formula (5-1). (wherein n is the same as defined above.)

[0053] Examples of acid-modified resins represented by formula (5) include resins obtained by modifying the resin represented by formula (5) with a carboxylic acid or a carboxylic acid derivative. As the carboxylic acid or carboxylic acid derivative, unsaturated carboxylic acids and their derivatives are preferred from the viewpoint of reactivity with the resin represented by formula (5). Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, sorbic acid, mesaconic acid, and angelic acid. Examples of derivatives of unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, and metal salts, among which acid anhydrides are preferred. Among the above, from the viewpoints of exhibiting high flame retardancy and availability, the acid-modified resin represented by formula (5) is preferably a resin obtained by modifying the resin represented by formula (5) with maleic acid or a maleic acid derivative (a maleic acid-modified resin represented by formula (5)), and more preferably a resin obtained by modifying the resin represented by formula (5) with maleic anhydride.

[0054] Examples of the maleic acid modified resin represented by the formula (5) include resins having a structure represented by the following formula (5-2) and / or the following formula (5-3). (In the formula, R ５１ ~R ５５ , R ６１ , R ６３ , R ６４ , R ６５ , and n are the same as above.)

[0055] The acid-modified product of the resin represented by formula (5) preferably has an acid-modification ratio of 0.01 to 5.0% by mass, more preferably 0.05 to 3.0% by mass, even more preferably 0.1 to 2.0% by mass, and even more preferably 0.2 to 1.0% by mass, from the viewpoints of obtaining low dielectric properties, improving film formability, and availability. The acid-modification ratio here refers to the content (% by mass) of acid-derived structures in the acid-modified product. For example, when the acid-modified product of the resin represented by formula (5) is a resin obtained by modifying the resin represented by formula (5) with maleic anhydride, the acid-modification ratio refers to the content (% by mass) of structures derived from maleic anhydride in the acid-modified product.

[0056] From the viewpoints of exhibiting high flame retardancy and availability, component (B) is preferably a resin represented by the formula (5) or a maleic acid-modified product thereof, more preferably a resin represented by the formula (5), and even more preferably poly(2,6-dimethyl-1,4-phenylene ether), which is a resin represented by the formula (5-1).

[0057] The intrinsic viscosity of component (B), measured in chloroform at 30°C, is preferably 0.20 to 0.60 dL / g, more preferably 0.30 to 0.50 dL / g, and even more preferably 0.30 to 0.45 dL / g, from the viewpoint of exhibiting high flame retardancy and improving moldability.

[0058] As the resin represented by the formula (5), commercially available products such as "PX100F" (poly(2,6-dimethyl-1,4-phenylene ether), Tg = 207°C, intrinsic viscosity at 30°C measured in chloroform = 0.37 dL / g) manufactured by Polyxylenol Singapore Pte. Ltd. and "PX100L" (poly(2,6-dimethyl-1,4-phenylene ether), Tg = 210°C, intrinsic viscosity at 30°C measured in chloroform = 0.47 dL / g) can also be used. Commercially available products of resins (maleic acid modified products) obtained by modifying the resin represented by the formula (5) with maleic anhydride include "Iupiace PME-80" (maleic anhydride modification rate: 0.38% by mass) manufactured by Mitsubishi Engineering-Plastics Corporation.

[0059] <Content> The ratio of the mass content of component (B) to the total mass content of components (A) and (B) in the resin composition [(B) / {(A)+(B)}] is more than 0.50, preferably 0.60 or more, more preferably 0.65 or more, even more preferably 0.70 or more, still more preferably 0.75 or more, and still more preferably 0.80 or more, from the viewpoint of exhibiting high flame retardancy and obtaining low dielectric properties. The upper limit is less than 1.00, and from the viewpoint of exhibiting high flame retardancy, it is preferably 0.99 or less, more preferably 0.98 or less, and even more preferably 0.95 or less.

[0060] The content of component (A) in the resin composition is not particularly limited as long as it is within a range in which the ratio [(B) / {(A)+(B)}] exceeds 0.50. From the viewpoint of achieving high flame retardancy and low dielectric properties, the content is preferably 1 to 45 mass%, more preferably 2 to 40 mass%, even more preferably 5 to 30 mass%, and still more preferably 5 to 25 mass%.

[0061] The content of component (B) in the resin composition is not particularly limited as long as it is within a range in which the ratio [(B) / {(A)+(B)}] exceeds 0.50. From the viewpoint of achieving high flame retardancy and low dielectric properties, the content is preferably 30 to 99.5 mass%, more preferably 40 to 99.5 mass%, even more preferably 50 to 99.5 mass%, still more preferably 60 to 98 mass%, still more preferably 70 to 95 mass%, and still more preferably 75 to 95 mass%.

[0062] <Additives> The resin composition of the present invention may contain additives such as fillers, reinforcing fibers, delustering agents, plasticizers, antistatic agents, coloring inhibitors, antigelling agents, colorants, sliding property improvers, antioxidants, conductive agents, resin modifiers, compatibilizers, etc. When the above additives are used, there are no particular restrictions on the amount thereof, but from the viewpoint of exhibiting the effects of the additives while maintaining high flame retardancy, the amount thereof in the resin composition is usually 50% by mass or less, preferably 0.0001 to 30% by mass, more preferably 0.001 to 15% by mass, and even more preferably 0.01 to 10% by mass.

[0063] Furthermore, the resin composition of the present invention can contain resins other than component (A) and component (B) as long as the properties of the composition are not impaired. Such resins are preferably highly heat-resistant thermoplastic resins, such as polyamide resins, polyester resins, polyimide resins other than polyimide resin (A), polycarbonate resins, polyetherimide resins, polyamideimide resins, polyphenylene etherimide resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyarylate resins, liquid crystal polymers, polyetheretherketone resins, polyetherketone resins, polyetherketoneketone resins, polyetheretherketoneketone resins, polybenzimidazole resins, and fluorine-based resins. Examples of fluorine-based resins include polytetrafluoroethylene, perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-ethylene copolymers, polyvinylidene fluoride, and polychlorotrifluoroethylene. Among these, from the viewpoints of heat resistance, moldability, strength, and solvent resistance, one or more selected from the group consisting of polyetherimide resins, polyphenylene sulfide resins, and polyether ether ketone resins are preferred, from the viewpoint of low water absorption, liquid crystal polymers are preferred, and from the viewpoint of obtaining high flame retardancy, one or more selected from the group consisting of polyphenylene sulfide resins, polytetrafluoroethylene, and perfluoroalkyl vinyl ether copolymers are preferred. When resins other than component (A) and component (B) are used in combination, there are no particular restrictions on the amount of the resins added, as long as the properties of the resin composition are not impaired.

[0064] However, from the viewpoint of obtaining the effects of the present invention, the total content of component (A) and component (B) in the resin composition of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, and still more preferably 95% by mass or more, and is 100% by mass or less.

[0065] The resin composition of the present invention can exhibit high flame retardancy even with a small flame retardant content. From this perspective, the content of the flame retardant in the resin composition is preferably 5% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, still more preferably 0.5% by mass or less, still more preferably 0.2% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.05% by mass or less, still more preferably 0.02% by mass or less, still more preferably less than 0.01% by mass, and still more preferably 0% by mass. Examples of the flame retardant include existing flame retardants such as halogen-based flame retardants, phenol-based flame retardants, phosphorus-based flame retardants, metal oxide-based flame retardants, metal hydroxide-based flame retardants, metal salt-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, and boron compound-based flame retardants.

[0066] From the viewpoint of forming pellets, the resin composition of the present invention preferably does not contain a solvent. Specifically, the content of the solvent in the resin composition is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.1% by mass or less.

[0067] <Form of Resin Composition> The resin composition of the present invention can take any form. However, from the viewpoint of exhibiting high flame retardancy by forming a microphase-separated structure (described later) and obtaining low dielectric properties, the resin composition is preferably obtained by melt-kneading at a temperature above the melting point of component (A), and more preferably is a pellet obtained by melt-kneading at a temperature above the melting point of component (A). That is, component (A) in the resin composition of the present invention is preferably subjected to thermal history, and such a resin composition is distinguished from a resin composition containing component (A) in a powder state. Because the resin composition of the present invention is thermoplastic, for example, after adding and dry-blending component (A), component (B), and various optional components as needed, or after separately feeding component (B) and optional components from a location separate from the feed of component (A) into the extruder, the composition can be melt-kneaded in the extruder to extrude strands, and the strands can be cut to pelletize. Furthermore, by introducing the pellets into various molding machines and thermoforming them using the method described below, molded articles having desired shapes can be easily produced. In a resin composition containing a flame retardant, bleeding out or thermal decomposition of the flame retardant, discoloration, whitening, etc. are usually likely to occur during the pellet production process and thermoforming process. However, the resin composition of the present invention has the advantage that these problems do not occur.

[0068] Pellets made from the resin composition of the present invention and molded articles obtained by molding the resin composition preferably have a microphase-separated structure from the viewpoints of exhibiting high flame retardancy and obtaining low dielectric properties. The microphase-separated structure is a phase-separated structure at the micro to nano level formed by phase separation between component (A) and component (B), and may be a sea-island structure or a co-continuous structure, but a sea-island structure is preferred. In a sea-island structure, either component may form the "sea" depending on the mass ratio of component (A) to component (B) in the pellet. Whether or not a pellet or molded article has a microphase-separated structure can be determined by observing the surface or cross section of the pellet or molded article with a scanning transmission electron microscope (STEM).

[0069] [Molded Article] The present invention provides a molded article comprising the resin composition. The shape of the molded article is not particularly limited, and examples thereof include a sheet, a film, a strand, a filament, etc. These may be intermediate parts for industrial products or final products.

[0070] Since the resin composition of the present invention has thermoplasticity, the molded article of the present invention can be easily produced by thermoforming. Examples of thermoforming methods include injection molding, extrusion molding, inflation molding, blow molding, hot press molding, vacuum molding, pressure molding, laser molding, welding, and welding. Any molding method involving a thermal melting step can be used. From the viewpoint of the moldability of the resin composition, the molded article of the present invention is preferably an injection-molded article. When the resin composition is injection-molded, this is preferred because molding can be performed without setting the molding temperature and mold temperature during molding to high temperatures. For example, injection molding can be performed at a molding temperature of preferably 400°C or less, more preferably 360°C or less, and a mold temperature of preferably 260°C or less, more preferably 220°C or less.

[0071] As a method for producing a molded body, for example, the pellets produced by the above method are dried, and then the pellets are introduced into various molding machines and thermoformed to produce a molded body having a desired shape.

[0072] <Flame Retardancy> The resin composition and molded article of the present invention have high flame retardancy. Specifically, the oxygen index of the molded article having a thickness of 4 mm, measured in accordance with JIS K 7201:1995, is preferably 28 or more, more preferably 28.5 or more, even more preferably 29 or more, even more preferably 30 or more, and even more preferably 32 or more. The degree of flame retardancy can be confirmed by measuring the oxygen index as one indicator of flame retardancy. The oxygen index represents the oxygen concentration required to sustain combustion; if it exceeds 21, combustion will not continue in air under normal conditions. In addition, an oxygen index of 27 or more is generally considered to indicate high flame retardancy. Specifically, the oxygen index can be measured by the method described in the examples.

[0073] <Low Dielectric Properties> The resin composition and molded article of the present invention have low dielectric properties, and can achieve, for example, a dielectric constant of 3.0 or less and a dielectric loss tangent of 0.005 or less at a measurement frequency of 10 GHz. The dielectric constant is preferably 2.90 or less, more preferably 2.85 or less, even more preferably 2.70 or less, and even more preferably 2.50 or less, and the dielectric loss tangent is preferably 0.004 or less, more preferably 0.003 or less. The dielectric constant and dielectric loss tangent can be measured specifically by the methods described in the examples.

[0074] <Adhesion> The resin composition and molded article of the present invention also have good adhesion to metal foils such as copper foils. Therefore, the resin composition and molded article of the present invention can also be used in metal foil laminates such as copper-clad laminates. The adhesion of the molded article made of the resin composition of the present invention to copper foil can be evaluated by the method described in the examples.

[0075] <Applications> The resin composition and molded article of the present invention are suitable for applications requiring high flame retardancy, a low dielectric constant, and a low dielectric dissipation factor, such as components related to 6th generation mobile communication systems (6G) using 5G or frequency bands of 70 GHz to 300 GHz (smartphones, flexible printed circuit boards, metal foil laminates such as copper-clad laminates, antennas, antenna substrates, etc.), various antennas other than those mentioned above (microwave antennas, millimeter wave antennas, waveguide slot antennas, horn antennas, lens antennas, printed antennas, triplate antennas, microstrip antennas, patch antennas, etc.), various antenna substrates (antenna substrates for 77 GHz automotive millimeter wave radar, antenna substrates for terahertz wave radar, antenna substrates for aircraft radar, antenna substrates for tracked special vehicles, antenna substrates for WiGig, etc.), wire coating materials (low dielectric wire coating materials, etc.), bonding sheets, insulating films, raw materials for carbon fiber reinforced plastics (CFRP), high frequency circuit boards, printed wiring boards, chip-on-film (COF) frames, etc. Flexible substrates, multilayer laminates, LED-mounted substrates, industrial robot substrates, communication substrates for household robots, semiconductor element materials, wafers for high-frequency devices, Wi-Fi chips, wireless communication devices, transmission lines (coaxial lines, strip lines, microstrip lines, coplanar lines, parallel lines, etc.), bearing coatings, heat-insulating shafts, trays, various belts (seamless belts, etc.), heat-resistant low-dielectric tapes, heat-resistant low-dielectric tubes, various sensors (touch sensors, etc.), various radars (automotive radars, aerospace radars, etc.), radomes (radar domes), optical communication modules (TOSA / ROSA), 8k-TV cables, mobile terminals or digital home appliances (tablet terminals, notebook PCs, flat-screen TVs, retractable TVs, digital cameras, smart glasses, smart watches, etc.), base stations (macrocell base stations, small cell base stations, C-RAN base stations, etc.), drones (commercial drones, long-distance drones, etc.), surveillance cameras, indoor or outdoor servers, artificial satellites, space station communications equipment, etc.

[0076] The present invention will now be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, various measurements and evaluations in each production example and example were carried out as follows.

[0077] <Infrared Spectroscopic Analysis (IR Measurement)> IR measurement of the polyimide resin was carried out using a JEOL Ltd. "JIR-WINSPEC50".

[0078] <Logarithmic Viscosity μ> A polyimide resin was dried at 190 to 200°C for 2 hours, and then 0.100 g of the polyimide resin was dissolved in 20 mL of concentrated sulfuric acid (96%, manufactured by Kanto Chemical Co., Inc.) to prepare a polyimide resin solution. Measurement was carried out at 30°C using a Cannon-Fenske viscometer. Logarithmic viscosity μ was calculated using the following formula: μ = ln[(ts / t ０ ) / C] t ０ : Time during which concentrated sulfuric acid flows ts: Time during which polyimide resin solution flows C: 0.5 g / dL

[0079] <Melting point, glass transition temperature, crystallization temperature, heat of fusion, heat of crystallization> The melting point Tm, glass transition temperature Tg, crystallization temperature Tc, heat of fusion Hm, and heat of crystallization Hc of the resin used alone in each example or the resin composition obtained in each example were measured using a differential scanning calorimeter (TA Instruments' "DSC-25"). In measuring the crystallization temperature Tc, resin powder was used for the polyimide resin, and pellets were used for the crystalline thermoplastic resin composition as the measurement sample. Under a nitrogen atmosphere, the measurement sample was subjected to the following thermal history conditions. The thermal history conditions were a first temperature rise (heating rate 10 ° C. / min), followed by cooling (cooling rate 20 ° C. / min), followed by a second temperature rise (heating rate 10 ° C. / min). The melting point Tm was determined by reading the peak top value of the endothermic peak observed during the second temperature rise. The glass transition temperature Tg was determined by reading the value observed during the second temperature rise. The crystallization temperature Tc was determined by reading the peak top value of the exothermic peak observed during cooling. For Tm, Tg, and Tc, when multiple peaks were observed, the peak top value of each peak was read. The heat of fusion Hm (mJ / mg) was calculated from the area of ​​the heat of fusion peak (endothermic peak) near the melting point observed when the measurement sample was heated to a temperature above the melting point at a heating rate of 10°C / min, melted, cooled at a heating rate of 20°C / min, and then melted again at a heating rate of 10°C / min. The heat of crystallization Hc (mJ / mg) was calculated from the area of ​​the exothermic crystallization peak observed when the measurement sample was heated to a temperature above the melting point at a heating rate of 10°C / min, melted, and then cooled at a heating rate of 20°C / min.

[0080] <Crystallization Half Time> The crystallization half time of the polyimide resin was measured using a differential scanning calorimeter (DSC-6220 manufactured by SII Nanotechnology, Inc.). The polyimide resin was held at 420°C for 10 minutes in a nitrogen atmosphere to completely melt it, and then rapidly cooled at a cooling rate of 70°C / min. The time required from the appearance of the observed crystallization peak to the peak top was calculated. In Table 1, crystallization half times of 20 seconds or less are indicated as "<20".

[0081] <Weight-average molecular weight> The weight-average molecular weight (Mw) of the polyimide resin was measured using a gel permeation chromatography (GPC) measuring device "Shodex GPC-101" manufactured by Showa Denko K.K. under the following conditions: Column: Shodex HFIP-806M Mobile phase solvent: hexafluoroisopropanol (HFIP) containing 2 mM sodium trifluoroacetate Column temperature: 40°C Mobile phase flow rate: 1.0 mL / min Sample concentration: approximately 0.1% by mass Detector: IR detector Injection volume: 100 μm Calibration curve: standard PMMA

[0082] <Heat distortion temperature (HDT)> Using the resin alone used in each example or the resin composition obtained in each example, an injection-molded article measuring 80 mm x 10 mm x 4 mm thick was produced by the method described below and used for measurement. Measurements were performed in accordance with JIS K7191-1,2:2015, using a flatwise test. Specifically, the heat distortion temperature was measured using an HDT tester "Auto-HDT3D-2" (manufactured by Toyo Seiki Seisakusho, Ltd.) under conditions of a support distance of 64 mm, a load of 1.80 MPa, and a heating rate of 120°C / hour.

[0083] <Dielectric Constant, Dielectric Loss Tangent> A 1.5 mm thick injection molded article was prepared using the resin alone used in each example, or pellets of the resin composition obtained in each example, by the method described below. This was then machined to prepare test pieces measuring 60 mm x 1.5 mm x 1.5 mm thick, which were used for measurements. Using a PNA Network Analyzer N5222B manufactured by Keyside Technology Co., Ltd. and a cavity resonator CP531 manufactured by Kanto Electronics Application Development Co., Ltd., the dielectric constant and dielectric loss tangent were measured at a temperature of 23°C, humidity of 50%, and a measurement frequency of 10 GHz by the cavity resonator perturbation method in accordance with IEC 62810. The measured values ​​were averaged over two measurements. The test pieces were conditioned at a temperature of 23°C and humidity of 50% for at least 24 hours and then immediately used for measurements.

[0084] <Oxygen Index> Using the resin compositions produced in each example, injection-molded articles measuring 80 mm × 10 mm × 4 mm thick were produced by the method described below. Using these molded articles as test pieces, the oxygen index was measured using a candle combustion tester Type D (manufactured by Toyo Seiki Seisakusho, Ltd.) according to JIS K 7201:1995.

[0085] Production Example 1 (Production of Polyimide Resin 1) 500 g of 2-(2-methoxyethoxy)ethanol (manufactured by Nippon Nyukazai Co., Ltd.) and 218.12 g (1.00 mol) of pyromellitic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were introduced into a 2 L separable flask equipped with a Dean-Stark apparatus, a Liebig condenser, a thermocouple, and four paddle blades. After nitrogen flow, the mixture was stirred at 150 rpm to obtain a uniform suspension. Meanwhile, using a 500 mL beaker, 49.79 g (0.35 mol) of 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., cis / trans ratio = 7 / 3) and 93.77 g (0.65 mol) of 1,8-octamethylenediamine (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 250 g of 2-(2-methoxyethoxy)ethanol to prepare a mixed diamine solution. This mixed diamine solution was gradually added using a plunger pump. Although heat was generated during the dropwise addition, the internal temperature was adjusted to remain within the range of 40 to 80°C. During the dropwise addition of the mixed diamine solution, nitrogen flow was maintained throughout, and the stirring impeller rotation speed was set to 250 rpm. After the dropwise addition was completed, 130 g of 2-(2-methoxyethoxy)ethanol and 1.284 g (0.010 mol) of n-octylamine (Kanto Chemical Co., Inc.), an end-capping agent, were added and further stirred. At this stage, a pale yellow polyamic acid solution was obtained. Next, the stirring speed was increased to 200 rpm, and the polyamic acid solution in the 2-L separable flask was heated to 190°C. During the temperature increase, precipitation of polyimide resin powder and dehydration associated with imidization were observed between 120 and 140°C. After holding at 190°C for 30 minutes, the solution was allowed to cool to room temperature and then filtered. The obtained polyimide resin powder was washed with 300 g of 2-(2-methoxyethoxy)ethanol and 300 g of methanol, filtered, and then dried in a dryer at 180°C for 10 hours to obtain 317 g of powder of crystalline thermoplastic polyimide resin 1 (hereinafter also simply referred to as "polyimide resin 1"). The IR spectrum of polyimide resin 1 was measured, revealing a ν(C=O) 1768, 1697 (cm －１The inherent viscosity was 1.30 dL / g, Tm was 323°C, Tg was 184°C, Tc was 266°C, the heat of fusion was 26.7 mJ / mg, the heat of crystallization was 30.0 mJ / mg, the crystallization half time was 20 seconds or less, and the Mw was 55,000.

[0086] Production Example 2 (Production of Polyimide Resin 2) 769 g of 2-(2-methoxyethoxy)ethanol (manufactured by Nippon Nyukazai Co., Ltd.) and 174.50 g (0.80 mol) of pyromellitic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were introduced into a 2 L separable flask equipped with a Dean-Stark apparatus, a Liebig condenser, a thermocouple, and four paddle blades. After nitrogen flow, the mixture was stirred at 150 rpm to obtain a uniform suspension. Meanwhile, using a 500 mL beaker, 22.76 g (0.16 mol) of 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., cis / trans ratio = 7 / 3) and 92.33 g (0.64 mol) of 1,8-octamethylenediamine (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 250 g of 2-(2-methoxyethoxy)ethanol to prepare a mixed diamine solution. This mixed diamine solution was gradually added using a plunger pump. Although heat was generated during the dropwise addition, the internal temperature was adjusted to remain within the range of 40 to 80°C. During the dropwise addition of the mixed diamine solution, nitrogen flow was maintained throughout, and the stirring impeller rotation speed was set to 250 rpm. After the dropwise addition was completed, 10 g of 2-(2-methoxyethoxy)ethanol and 1.027 g (0.008 mol) of n-octylamine (Kanto Chemical Co., Inc.), an end-capping agent, were added and further stirred. At this stage, a pale yellow polyamic acid solution was obtained. Next, the stirring speed was increased to 200 rpm, and the polyamic acid solution in the 2-L separable flask was heated to 185°C. During the temperature increase, precipitation of polyimide resin powder and dehydration associated with imidization were observed between 120 and 140°C. After holding at 185°C for 30 minutes, the solution was allowed to cool to room temperature and then filtered. The obtained polyimide resin powder was washed with 600 g of methanol, filtered, and then dried in a dryer at 185°C for 10 hours to obtain 256 g of powder of crystalline thermoplastic polyimide resin 2 (hereinafter also simply referred to as "polyimide resin 2"). Polyimide resin 2 had a Tm of 344°C, a Tg of 166°C, a Tc of 299°C, a heat of fusion of 40 mJ / mg, a heat of crystallization of 35 mJ / mg, and an Mw of 36,000.

[0087] The compositions and evaluation results of the polyimide resins obtained in Production Examples 1 and 2 are shown in Table 1. The mole percentages of the tetracarboxylic acid component and the diamine component in Table 1 are values ​​calculated from the amounts of each component charged when the polyimide resin was produced.

[0088]

[0089] The abbreviations in Table 1 are as follows: PMDA: pyromellitic dianhydride 1,3-BAC: 1,3-bis(aminomethyl)cyclohexane OMDA: 1,8-octamethylenediamine n-OcA: n-octylamine

[0090] Example 1 (Preparation and Evaluation of Resin Composition and Molded Article) The powder of polyimide resin 1 obtained in Production Example 1 and the powder of component (B), poly(2,6-dimethyl-1,4-phenylene ether) (PX100F manufactured by Polyxylenol Singapore Pte. Ltd., Tg = 207°C, intrinsic viscosity at 30°C measured in chloroform = 0.37 dL / g) were dry blended in the proportions shown in Table 2, and then melt-kneaded and extruded using a co-rotating twin-screw kneading extruder (HK-25D manufactured by Parker Corporation, screw diameter 25 mmΦ, L / D = 41) at a barrel temperature of 330 to 340°C and a screw rotation speed of 120 rpm. The strand extruded from the extruder was air-cooled and then pelletized using a pelletizer (Fan Cutter FC-Mini-4 / N manufactured by Hoshi Plastics Co., Ltd.). The resulting pellets were dried at 80°C for 12 hours and then used for injection molding. Using an injection molding machine (FANUC Corporation's "ROBOSHOT α-S30iA"), injection molding was performed at a barrel temperature of 360°C, a mold temperature of 180°C, and a molding cycle of 72 seconds to produce injection-molded articles of the predetermined shape used in the above evaluations. The obtained pellets or injection-molded articles were used to perform various evaluations using the methods described above. The results are shown in Table 2.

[0091] Example 2, Comparative Examples 2 to 4 Pellets and injection-molded articles were prepared and evaluated in the same manner as in Example 1, except that the powder of polyimide resin 1 obtained in Production Example 1 and poly(2,6-dimethyl-1,4-phenylene ether) powder "PX100F" were used in the proportions shown in Table 2 and injection molding was performed with a molding cycle time of 65 to 72 seconds (Example 2: 73 seconds, Comparative Example 2: 65 seconds, Comparative Example 3: 67 seconds, Comparative Example 4: 77 seconds). The results are shown in Table 2.

[0092] Comparative Example 1 The powder of polyimide resin 1 obtained in Production Example 1 was melt-kneaded and extruded using a Laboplastomill (manufactured by Toyo Seiki Seisakusho, Ltd.) at a barrel temperature of 360°C and a screw rotation speed of 150 rpm. The strand extruded from the extruder was air-cooled and then pelletized using a pelletizer (Hoshi Plastics Co., Ltd.'s "Fan Cutter FC-Mini-4 / N"). The resulting pellets were dried at 150°C for 12 hours and then used for injection molding. Using an injection molding machine (Fanuc Corporation's "ROBOSHOT α-S30iA"), injection molding was performed at a barrel temperature of 350°C, a mold temperature of 200°C, and a molding cycle of 50 seconds to produce injection-molded articles of the specified shape used in the above evaluation (HDT measurement). The resulting pellets or injection-molded articles were used to perform various evaluations using the methods described above. The results are shown in Table 2.

[0093]

[0094] As shown in Table 2, the molded articles made from the resin compositions of Examples 1 and 2 have improved oxygen indexes compared to the molded articles of Comparative Examples 1 to 4, and are therefore highly flame retardant.

[0095] Comparative Examples 5 and 6, Examples 3 and 4 Pellets and injection-molded articles were prepared in the same manner as in Example 1, except that polyimide resin 2 obtained in Production Example 2 and powder of poly(2,6-dimethyl-1,4-phenylene ether) (PX100L manufactured by Polyxylenol Singapore Pte. Ltd., Tg = 210°C, intrinsic viscosity at 30°C measured in chloroform = 0.47 dL / g) as component (B) were used in the proportions shown in Table 3. The results are shown in Table 3.

[0096]

[0097] As shown in Table 3, the molded articles made from the resin compositions of Examples 3 and 4 also have higher oxygen indices and higher flame retardancy than the molded articles of Comparative Examples 5 and 6.

[0098] Details of each component shown in Tables 2 and 3 are as follows: <Component (A)> Polyimide resin 1: Crystalline thermoplastic polyimide resin 1 obtained in Production Example 1 Polyimide resin 2: Crystalline thermoplastic polyimide resin 2 obtained in Production Example 2 <Component (B)> PX100F: Poly(2,6-dimethyl-1,4-phenylene ether), "PX100F" manufactured by Polyxylenol Singapore Pte. Ltd., Tg = 207°C, intrinsic viscosity at 30°C measured in chloroform = 0.37 dL / g PX100L: Poly(2,6-dimethyl-1,4-phenylene ether), "PX100L" manufactured by Polyxylenol Singapore Pte. Ltd., Tg = 210°C, intrinsic viscosity at 30°C measured in chloroform = 0.47 dL / g

[0099] Furthermore, the morphology of the pellets obtained in Example 1 was confirmed by the following method. The pellet obtained in Example 1 was cut using an ultramicrotome (Leica Microsystems EM UC7) in a direction perpendicular to the pellet flow direction (MD) (i.e., so that the TD cross section was exposed) as shown in Figure 1 to prepare ultrathin sections. In Figure 1, 1 denotes the pellet and 2 denotes the ultrathin section. The section was stained in the vapor phase of ruthenium tetroxide for 30 minutes and then observed in transmission using a field emission scanning transmission electron microscope (FE-STEM, Carl Zeiss Gemini SEM500) with an accelerating voltage of 30 kV, column mode: Normal, aperture size: 20 μm, working distance: 3.6 mm, detection signal: aSTEM A, and observation magnification: 10,000 times using a STEM detector (Figure 2). In the observation image in Figure 2, dark areas correspond to stained areas, and light areas correspond to unstained areas. In the observation image, the dark areas were determined to be composed of resin (B), which is easily stained by ruthenium tetroxide. 2, it can be seen that the polyimide resin (A) and the resin (B) form a microphase-separated structure (sea-island structure) in the pellets obtained in Example 1. It is also presumed that the polyimide resin (A) forms the island portions, and the resin (B) forms the sea portion.

[0100] Example 1A (Film Production and Evaluation, and Evaluation of Adhesion Between the Film and Copper Foil) <Film Production> Pellets of the resin composition obtained in Example 1 were dried at 150°C for 10 hours and then fed into a φ20 mm single-screw extruder equipped with a 150 mm wide T-die and melt-kneaded at a resin temperature of 350 to 360°C. The melt-kneaded resin composition was continuously extruded through the T-die of the single-screw extruder and then cooled with a metal roll, which was a cooling roll at 140°C, to obtain a film with a thickness of 70 μm. Here, the temperature of the φ20 mm single-screw extruder was set to 335 to 340°C, and the temperature of the T-die was set to 335°C.

[0101] <Adhesion between Film and Copper Foil> A 10 cm x 10 cm film 3 prepared by the above method and a 10 cm x 10 cm x 12 μm thick copper foil 4 (rolled copper foil, JX Metals Corporation "TQ-MS-VSP") were prepared. As shown in FIG. 3(a), the copper foil 4 and film 3 were placed in this order on release paper (material: PTFE), with the copper foil 4 and film 3 overlapping by 1 cm (d = 1 cm in FIG. 3(a)). Another sheet of release paper was placed on top of this and heat-sealed using a thermal gradient tester (manufactured by Toyo Seiki Seisakusho, Ltd., heater: upper side). The heat-sealing conditions were a temperature of 250°C, a pressure of 0.4 MPa (gauge pressure) for 60 seconds. After heat sealing, the release paper was removed, and the film shown in FIG. 3(a) was cut in the MD direction to prepare a 1 cm wide strip-shaped test piece (FIG. 3(b)). The adhesive area between the film 3' and the copper foil 4' in FIG. 3(b) is 1 cm ２ Next, the short sides of the film 3' of the obtained test piece were held and the film was hung so that the long sides were parallel to the direction of gravity as shown in Figure 4. If the copper foil 4' on the bottom side did not fall off within 30 seconds, it was determined that there was adhesiveness.

[0102] <Tensile adhesive strength> Test specimens were prepared in the same manner as in the evaluation of "Adhesion between film and copper foil" above, and used for evaluation. The test specimens were placed in the gripping fixtures of a universal testing machine ("Strograph VG" manufactured by Toyo Seiki Seisaku-sho, Ltd.) with the film on top and the copper foil on the bottom, with the long sides parallel to the direction of gravity. A tensile shear test was carried out in accordance with JIS K 6849-1994 under the conditions of temperature: 23°C, test range: 200 N, and test speed: 5 mm / min, and the tensile adhesive strength (N / cm ２ ) was sought.

[0103] Example 2A A film was produced and evaluated in the same manner as in Example 1A, except that the resin composition used to produce the film was changed to the resin composition obtained in Example 2. The results are shown in Table 4.

[0104]

[0105] As can be seen from Table 4, the film made of the resin composition of the present invention has adhesiveness to copper foil, and therefore can also be used for metal foil laminates such as copper-clad laminates.

[0106] According to the present invention, it is possible to provide a resin composition and a molded article that can exhibit high flame retardancy even when a small amount of a flame retardant is used or no flame retardant is used at all.

[0107] 1 Pellet 2 Ultrathin slice 3, 3' Film 4, 4' Copper foil

Claims

1. A resin composition comprising: a polyimide resin (A) containing a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), wherein the content ratio of the repeating structural unit of formula (1) to the total of the repeating structural units of formula (1) and formula (2) is 20 to 70 mol %; and a resin represented by the following formula (5) or an acid-modified product thereof (B), wherein the ratio of the mass content of component (B) to the total mass content of component (A) and component (B), [(B) / {(A)+(B)}], is greater than 0.

50. 【Chemical 1】 (R １ is a divalent group having 6 to 22 carbon atoms and containing at least one alicyclic hydrocarbon structure. ２ is a divalent chain aliphatic group having 5 to 16 carbon atoms. １ and X ２ are each independently a tetravalent group containing at least one aromatic ring and having 6 to 22 carbon atoms. 【Chemistry 2】 (R ５１ ~R ５５ , and R ６１ ~R ６４ are each independently a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 4 carbon atoms, and R ６５ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and n is the number of repeating structural units and is a number of 10 or more.

2. The resin composition according to claim 1, wherein the total content of the component (A) and the component (B) in the resin composition is 50 mass% or more.

3. 2. The resin composition according to claim 1, wherein the component (B) has an intrinsic viscosity measured in chloroform at 30° C. of 0.20 to 0.60 dL / g.

4. The resin composition according to claim 1, wherein the resin composition is obtained by melt-kneading at a temperature exceeding the melting point of the component (A).

5. The resin composition according to claim 1 , wherein a pellet made of the resin composition has a microphase-separated structure.

6. A molded article comprising the resin composition according to any one of claims 1 to 5.

7. The molded article according to claim 6, which is an injection molded article.

8. The molded article according to claim 6, wherein the molded article has an oxygen index of 28 or more when measured in accordance with JIS K 7201:1995 and has a thickness of 4 mm.

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