Polyimide resin composition, molded body and method for producing same, and metal foil laminate

Abstract

Provided are: a polyimide resin composition containing a crystalline thermoplastic polyimide resin (A) having a prescribed structure and a phosphorus-containing compound (B) represented by formula (5); a molded body containing the polyimide resin composition; a method for producing the molded body; and a metal foil laminate. (R51 to R54 each independently are a C1-12 hydrocarbon group. Y is a divalent group represented by -R55-Z-R56-. R55 and R56 each independently are a single bond or a C1-12 alkylene group, and Z is an arylene group. n is an integer of 1-10.)

Description

Polyimide resin composition, molded body and method for producing the same, and metal foil laminate

[0001] The present invention relates to a polyimide resin composition, a molded article and a method for producing the same, and a metal foil laminate.

[0002] Polyimide resins are useful engineering plastics with high thermal stability, strength, and solvent resistance due to the rigidity of their molecular chains, 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, where general-purpose thermoplastic resins such as nylon and polyester cannot.

[0003] Among thermoplastic resins, crystalline thermoplastic resins have a melting point and exhibit fluidity at high temperatures, allowing for easy and inexpensive molding. In thermoforming of resin materials containing crystalline thermoplastic resins, controlling the crystallization rate of the resin is important. For example, Patent Document 1 proposes a resin composition containing a liquid crystal polymer of a predetermined structure and a polyimide resin, with the aim of improving the handleability, etc., of liquid crystal polymers, which have a high crystallization rate and a reduced elasticity when melted, during melt molding.

[0004] International Publication No. 2022 / 004471

[0005] The liquid crystal polymer used in the technology disclosed in Patent Document 1 has a high crystallization rate, so by reducing the crystallization rate, handling during melt molding is improved. However, depending on the type of crystalline thermoplastic resin, it may be desirable to increase the crystallization rate of the resin in order to improve the molding cycle during melt molding. The present invention aims to provide a polyimide resin composition containing a crystalline thermoplastic polyimide resin of a predetermined structure and having a crystallization rate higher than that of the resin alone, a molded product containing the same, a method for producing the same, and a metal foil laminate.

[0006] The present inventors have found that a polyimide resin composition containing a polyimide resin having a specific combination of different polyimide structural units in a specific ratio and a phosphorus-containing compound having a specific structure can solve the above problems. Specifically, the present invention relates to the following: [1] A polyimide resin composition comprising: (A) a crystalline thermoplastic polyimide resin 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 of the repeating structural units of formula (1) and the repeating structural units of formula (2) is 15 to 70 mol %; and (B) a phosphorus-containing compound represented by the following formula (5). (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 ５４ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is -R ５５ -Z-R ５６ - is a divalent group represented by R ５５ and R ５６ are each independently a single bond or an alkylene group having 1 to 12 carbon atoms, and Z is an arylene group. n is an integer of 1 to 10.) [2] The polyimide resin composition according to [1], wherein the content of the phosphorus-containing compound (B) in the polyimide resin composition is 0.5 to 30 parts by mass per 100 parts by mass of the crystalline thermoplastic polyimide resin (A). [3] The polyimide resin composition according to [1] or [2], wherein the total content of the crystalline thermoplastic polyimide resin (A) and the phosphorus-containing compound (B) in the polyimide resin composition is 50% by mass or more. [4] In the formula (5), R ５１ ~R ５４is a phenyl group, and n is 1. [5] The polyimide resin composition according to any one of [1] to [4], wherein Tm - Tc is 50°C or less, where Tm (°C) is the melting point of a pellet made of the polyimide resin composition and Tc (°C) is the crystallization temperature. [6] A molded article comprising the polyimide resin composition according to any one of [1] to [5]. [7] A method for producing a molded article, comprising a step of melt-kneading the polyimide resin composition according to any one of [1] to [5] at a temperature exceeding the melting point of the phosphorus-containing compound (B). [8] A metal foil laminate having a layer made of the molded article according to [6] and a layer made of metal foil.

[0007] According to the present invention, it is possible to provide a polyimide resin composition containing a crystalline thermoplastic polyimide resin of a predetermined structure and having a crystallization rate improved compared to that of the resin alone, a molded article containing the same, a method for producing the same, and a metal foil laminate.

[0008] [Definition] In this specification, the term "crystalline thermoplastic polyimide resin" refers to a polyimide resin having both a melting point and a glass transition temperature. In this specification, whether the crystallization rate of the polyimide resin composition of the present invention is improved compared to the case of the crystalline thermoplastic polyimide resin (A) alone is determined using Tm-Tc (°C), which is the difference between the melting point Tm and the crystallization temperature Tc, as an index. When the value of Tm-Tc (°C) of the polyimide resin composition is smaller than that of the case of the crystalline thermoplastic polyimide resin (A) alone, it can be considered that the crystallization rate is improved. The melting point, glass transition temperature, and crystallization temperature can be measured using a differential scanning calorimeter by the method described in the Examples.

[0009] [Polyimide Resin Composition] The polyimide resin composition of the present invention contains a crystalline thermoplastic 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 of the repeating structural unit of formula (1) relative to the total of the repeating structural units of formula (1) and formula (2) is 15 to 70 mol %, and a phosphorus-containing compound (B) represented by the following formula (5). (R １is 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 ５４ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is -R ５５ -Z-R ５６ - is a divalent group represented by R ５５ and R ５６ are each independently a single bond or an alkylene group having 1 to 12 carbon atoms, Z is an arylene group, and n is an integer of 1 to 10.

[0010] The polyimide resin composition of the present invention is a resin composition in which a crystalline thermoplastic polyimide resin (A) (hereinafter simply referred to as "polyimide resin (A)"), which is a combination of specific different polyimide structural units in the above-mentioned specific ratio, is combined with a specific phosphorus-containing compound (B) (hereinafter simply referred to as "compound (B)"), thereby achieving a higher crystallization rate than that of polyimide resin (A) alone. The reason why the above effect is achieved in the present invention is unclear, but it is thought to be as follows. Generally, a crystal nucleating agent or the like is used to improve the crystallization rate of a crystalline thermoplastic resin. When compound (B) is added to crystalline thermoplastic polyimide resin (A), compound (B) may act similarly to a crystal nucleating agent, which is thought to increase the crystallization temperature Tc of the resulting resin composition. Inorganic compounds may also be used as crystal nucleating agents. Inorganic compounds usually have no melting point or a high melting point exceeding 400°C, but compound (B) is an organic compound having a melting point comparable to or lower than that of crystalline thermoplastic polyimide resin (A), and therefore adding compound (B) to crystalline thermoplastic polyimide resin (A) has the effect of lowering the melting point Tm of the resulting resin composition. Therefore, the value of Tm - Tc becomes lower than that of crystalline thermoplastic polyimide resin (A) alone, and it is thought that the crystallization rate is improved.

[0011] Furthermore, by containing both the polyimide resin (A) and the compound (B), the polyimide resin composition of the present invention can suppress the molecular weight reduction of the polyimide resin (A) during melt-kneading and achieve high flame retardancy. The reason for this is believed to be that crosslinks are formed between the polyimide resin (A) and the compound (B) during melt-kneading to a degree that does not impair the melt flowability, thereby achieving the effect of suppressing the molecular weight reduction and the effect of improving flame retardancy. Furthermore, the compound (B) is a highly flame-retardant phosphorus-containing compound, and since it does not have an ester structure, it also has the characteristic of having high heat resistance. Therefore, when added to a polyimide resin (A) with a relatively high melting point and glass transition temperature, it is unlikely to undergo thermal decomposition, even when melt-kneaded at temperatures above the melting point of the polyimide resin (A), and is therefore believed to have a high effect of improving flame retardancy.

[0012] <Crystalline Thermoplastic Polyimide Resin (A)> The crystalline thermoplastic 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 of the repeating structural unit of formula (1) relative to the total of the repeating structural units of formula (1) and formula (2) is 15 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.

[0013] The polyimide resin (A) used in the present invention is a crystalline thermoplastic resin, and is preferably in the form of powder or pellets. Thermoplastic polyimide resins are formed by molding a polyimide precursor such as polyamic acid and then closing the imide rings, and 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.

[0014] The repeating structural unit of formula (1) is described in detail below. １is 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.

[0015] 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.

[0016] 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.

[0017] 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 １has 6 to 22 carbon atoms, preferably 6 to 18. １ contains at least one aromatic ring, preferably 1 to 3.

[0018] 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 , R １５ , 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.

[0019] X １is particularly preferably a tetravalent group represented by the following formula (X-5) or (X-6).

[0020] 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.

[0021] Also, R ２ Another 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. ２is 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).

[0022] X ２ is X in formula (1). １ The definitions and preferred embodiments are the same as above.

[0023] 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 15 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 15 mol%, molding processability decreases, and if it exceeds 70 mol%, crystallinity decreases, resulting in reduced 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, even more preferably 50 mol% or less, and even more preferably less than 40 mol%. From the viewpoint of achieving high crystallinity, it is even more preferably 35 mol% or less. From the viewpoint of achieving high crystallinity, the content ratio is preferably 20 mol% or more.

[0024] 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 %.

[0025] 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.

[0026] R ３is 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.

[0027] 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 , p ２２ 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. ３is 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 in 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.

[0028] X ３ is X in formula (1). １ The definitions and preferred embodiments are the same as above.

[0029] 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.

[0030] 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.

[0031] The content of the linear aliphatic groups having 5 to 14 carbon atoms in the polyimide resin (A) is preferably 0.01 to 10 mol%, more preferably 0.1 to 6 mol%, and even more preferably 0.2 to 3.5 mol%, based on 100 mol% of the total of all repeating structural units constituting the polyimide resin (A). When the content of the linear aliphatic groups having 5 to 14 carbon atoms in the polyimide resin (A) is 0.01 mol% or more based on 100 mol% of the total of all repeating structural units constituting the polyimide resin (A), excellent heat aging resistance is exhibited, while when it is 10 mol% or less, sufficient molecular weight is ensured and good mechanical properties are obtained. Here, "the total of all repeating structural units constituting the polyimide resin (A)" refers to the sum of the repeating structural units represented by the formulas (1), (2), (3), and (4). The content of the linear aliphatic groups having 5 to 14 carbon atoms in the polyimide resin (A) can be determined by depolymerizing the polyimide resin (A).

[0032] 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 Tm of the polyimide resin (A) is preferably 270°C or higher, more preferably 280°C or higher, even more preferably 290°C or higher, still more preferably 300°C or higher, still more preferably 310°C or higher, and still more preferably 315°C or higher. From the viewpoint of exhibiting high moldability, it is preferably 345°C or lower. Furthermore, from the viewpoint of exhibiting high moldability, the glass transition temperature Tg of the polyimide resin (A) is preferably 250°C or lower, more preferably 230°C or lower, and even more preferably 200°C or lower.

[0033] The crystallization temperature Tc of the polyimide resin (A) is preferably 200°C or higher, more preferably 220°C or higher, and even more preferably 250°C or higher from the viewpoint of heat resistance, and is preferably 350°C or lower, more preferably 320°C or lower, and even more preferably 300°C or lower from the viewpoint of moldability.

[0034] From the viewpoints of crystallinity, heat resistance, mechanical strength, and chemical resistance, the polyimide resin (A) preferably has a heat of fusion Hm of 5.0 J / g or more, more preferably 10 J / g or more, and even more preferably 17 J / g or more. The upper limit of the heat of fusion Hm is not particularly limited, but is usually 45 J / g or less. The heat of fusion Hm of the polyimide resin (A) is calculated by differential scanning calorimetry from the area of ​​the heat of fusion peak (endothermic peak) observed near the melting point when the polyimide resin (A) is heated at a heating rate of 10°C / min to melt at a temperature above the melting point, then cooled at a heating rate of 20°C / min, and then heated again at a heating rate of 10°C / min to melt.

[0035] From the viewpoints of crystallinity, heat resistance, mechanical strength, and chemical resistance, the polyimide resin (A) preferably has a heat of crystallization Hc of 5.0 J / g or more, more preferably 10 J / g or more, and even more preferably 17 J / g or more. The upper limit of the heat of crystallization Hc is not particularly limited, but is usually 45 J / g or less. The heat of crystallization Hc of the polyimide resin (A) refers to the heat of the exothermic crystallization peak observed when the polyimide resin (A) is melted and then cooled at a temperature drop rate of 20°C / min using a differential scanning calorimeter. The melting point Tm, glass transition temperature Tg, crystallization temperature Tc, heat of fusion Hm, and heat of crystallization Hc of the polyimide resin (A) can be specifically measured by the methods described in the Examples.

[0036] 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 25,000 to 70,000, and even more preferably 25,000 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, 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.

[0037] (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.

[0038] 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.

[0039] 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.

[0040] The tetracarboxylic acid and / or derivative thereof containing at least one aromatic ring may be at least one compound selected from the above, which may be used alone, or two or more compounds may be used in combination.

[0041] 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.

[0042] 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.

[0043] In producing the polyimide resin (A), the molar ratio of the amount of the diamine containing at least one alicyclic hydrocarbon structure to the total amount of the diamine containing at least one alicyclic hydrocarbon structure and the chain aliphatic diamine is preferably 15 to 70 mol %. This molar amount is preferably 20 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.

[0044] 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.

[0045] 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%.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] From the viewpoint of obtaining the effects of the present invention, the content of the polyimide resin (A) in the polyimide resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 88% by mass or more, and is preferably 99.5% by mass or less.

[0050] <Phosphorus-Containing Compound (B)> The polyimide resin composition of the present invention contains a polyimide resin (A) and a phosphorus-containing compound (B) represented by the following formula (5): By blending the compound (B) with the polyimide resin (A) having the specific structure, a polyimide resin composition having a crystallization rate improved compared to the case of the polyimide resin (A) alone can be obtained. (R ５１ ~R ５４ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is -R ５５ -Z-R ５６ - is a divalent group represented by R ５５ and R ５６ are each independently a single bond or an alkylene group having 1 to 12 carbon atoms, Z is an arylene group, and n is an integer of 1 to 10.

[0051] In formula (5), R ５１ ~R ５４ The hydrocarbon group having 1 to 12 carbon atoms in the formula (I) is preferably an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms, and from the viewpoint of improving the crystallization rate and heat resistance, an aryl group having 6 to 12 carbon atoms is preferred. Examples of the aryl group include a phenyl group, a toluyl group, a mesityl group, a biphenyl group, and a naphthyl group, and a phenyl group is preferred.

[0052] In formula (5), Y is -R ５５ -Z-R ５６ - is a divalent group represented by R ５５ and R ５６ are each independently a single bond or an alkylene group having 1 to 12 carbon atoms, preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, and even more preferably an alkylene group having 1 to 4 carbon atoms. The alkylene group is preferably one or more selected from the group consisting of a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, and an isobutylene group, more preferably one or more selected from the group consisting of a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group, and even more preferably a methylene group.

[0053] -R ５５ -Z-R ５６ In the divalent group represented by -, Z is an arylene group, such as a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 4,4'-biphenylene group, a 2,6-naphthylene group, etc. Among these, from the viewpoint of improving the crystallization rate, a 1,3-phenylene group or a 1,4-phenylene group is preferred, and a 1,4-phenylene group is more preferred.

[0054] In formula (5), n is an integer of 1 to 10, preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, and even more preferably 1.

[0055] The melting point of the phosphorus-containing compound (B) is preferably 250 to 360°C, more preferably 280 to 355°C, and even more preferably 300 to 350°C. A melting point of the phosphorus-containing compound (B) of 250°C or higher is advantageous in terms of heat resistance, while a melting point of 360°C or lower reduces the Tm-Tc value of the resulting polyimide resin composition compared to the case of the polyimide resin (A) alone, making it easier to improve the crystallization rate. The melting point of the phosphorus-containing compound (B) can be measured using a differential scanning calorimeter.

[0056] From the viewpoint of improving the crystallization rate and the heat resistance, the phosphorus-containing compound (B) is a compound represented by the formula (5) in which R ５１ ~R ５４ is preferably a phenyl group, and n is preferably 1. A specific example of the phosphorus-containing compound (B) is a compound represented by the following structural formula (1,4-bis[(diphenylphosphoroso)methyl]benzene).

[0057] The content of the phosphorus-containing compound (B) in the polyimide resin composition is preferably 0.5 to 30 parts by mass, more preferably 0.5 to 25 parts by mass, even more preferably 1 to 20 parts by mass, still more preferably 2 to 15 parts by mass, even more preferably 3 to 15 parts by mass, still more preferably 5 to 15 parts by mass, and still more preferably 8 to 15 parts by mass, relative to 100 parts by mass of the polyimide resin (A). When the content of the phosphorus-containing compound (B) is 0.5 parts by mass or more relative to 100 parts by mass of the polyimide resin (A), the crystallization rate improving effect and flame retardancy can be easily imparted, and when it is 30 parts by mass or less, good appearance and heat resistance can be maintained.

[0058] <Additives> The polyimide 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, 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 the physical properties inherent in the polyimide resin (A), the amount thereof in the polyimide 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.

[0059] The polyimide resin composition of the present invention may contain resins other than the polyimide resin (A) to the extent that their properties are not impaired. Such resins are preferably highly heat-resistant thermoplastic resins, such as polyamide resins, polyester resins, polyimide resins other than the polyimide resin (A), polycarbonate resins, polyetherimide resins, polyamideimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyarylate resins, liquid crystal polymers, polyetheretherketone resins, polyetherketone resins, polyetherketoneketone resins, polyetheretherketoneketone resins, polybenzimidazole resins, and the like. Among these, from the viewpoints of heat resistance, moldability, strength, and solvent resistance, one or more resins selected from the group consisting of polyetherimide resins, polyphenylene sulfide resins, and polyetheretherketone resins are preferred. Liquid crystal polymers are preferred from the viewpoint of low water absorption, and polyphenylene sulfide resins are preferred from the viewpoint of achieving high flame retardancy. When the polyimide resin (A) is used in combination with other resins, there are no particular limitations on the blending ratio, as long as the properties of the polyimide resin composition are not impaired.

[0060] However, from the viewpoint of obtaining the effects of the present invention, the total content of the polyimide resin (A) and the phosphorus-containing compound (B) in the polyimide resin composition of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, even 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, but is 100% by mass or less.

[0061] The polyimide resin composition of the present invention can take any form, but is preferably in the form of pellets. Because the polyimide resin composition of the present invention and the polyimide resin (A) used therein are thermoplastic, for example, the polyimide resin (A), the phosphorus-containing compound (B), and various optional components, if necessary, can be dry-blended, or the phosphorus-containing compound (B) and optional components can be separately fed into the extruder from a location separate from the feed of the polyimide resin (A), followed by melt-kneading in the extruder to extrude strands, which can then be cut and pelletized. Furthermore, molded articles having desired shapes can be easily produced by introducing the pellets into various molding machines and thermoforming them using the methods described below. From the viewpoint of pelletization, the polyimide resin composition of the present invention preferably does not contain a solvent. Specifically, the solvent content in the polyimide 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.

[0062] <Thermal Properties of Polyimide Resin Composition> The polyimide resin composition of the present invention has a high crystallization rate. For example, when the melting point of a pellet made of the polyimide resin composition is Tm (°C) and the crystallization temperature is Tc (°C), Tm - Tc is preferably 52°C or less, more preferably 50°C or less, even more preferably 48°C or less, and even more preferably 45°C or less. The lower limit is 0°C or more, and from the viewpoint of improving moldability, it is preferably 10°C or more, more preferably 20°C or more. The melting point and crystallization temperature of the pellet made of the polyimide resin composition can be measured by the same method as for polyimide resin (A).

[0063] [Molded Article] The present invention provides a molded article comprising the polyimide 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.

[0064] [Method for Producing Molded Article] The polyimide resin composition of the present invention has thermoplasticity, and therefore, the molded article of the present invention can be easily produced by thermoforming. Thermoforming methods include injection molding, extrusion molding, inflation molding, blow molding, hot press molding, vacuum forming, pressure forming, laser forming, welding, and adhesion, and any molding method that involves a thermal melting step can be used.

[0065] The method for producing a molded article of the present invention preferably includes a step of melt-kneading the polyimide resin composition at a temperature exceeding the melting point of the phosphorus-containing compound (B). This allows the phosphorus-containing compound (B) to be uniformly dispersed in the polyimide resin composition, and furthermore, the Tm-Tc value of the resulting polyimide resin composition is lower than that of the polyimide resin (A) alone, making it easier to improve the crystallization rate. From the above viewpoints, the temperature during melt-kneading of the polyimide resin composition is preferably a temperature exceeding the melting point of the phosphorus-containing compound (B), more preferably a temperature at least 5°C above the melting point of the phosphorus-containing compound (B), and even more preferably a temperature at least 10°C above the melting point of the phosphorus-containing compound (B).

[0066] The temperature at which the polyimide resin composition is melt-kneaded is preferably a temperature exceeding the melting point of the polyimide resin (A). From the viewpoint of melting the polyimide resin (A) and suppressing deterioration of the polyimide resin (A) and the phosphorus-containing compound (B), the temperature is preferably in the range of 250 to 400°C, more preferably 290 to 360°C.

[0067] Specific procedures for producing a molded article include, for example, the following method. First, the phosphorus-containing compound (B) and, if necessary, various optional components are added to the polyimide resin (A) and dry-blended, and then the mixture is introduced into an extruder, melt-kneaded, and extruded to produce pellets. Alternatively, the polyimide resin (A) may be introduced into an extruder and melted, and the phosphorus-containing compound (B) and, if necessary, various optional components are introduced therein, and melt-kneaded with the polyimide resin (A) in the extruder and extruded to produce the pellets. The pellets may be dried and then introduced into various molding machines and thermoformed at preferably 250 to 400°C, more preferably 290 to 360°C, to produce a molded article having a desired shape.

[0068] <Flame Retardancy> The polyimide resin composition and molded article of the present invention exhibit high flame retardancy because they contain the polyimide resin (A) and the phosphorus-containing compound (B). The flame retardancy can be evaluated by a method in accordance with the UL94VTM test (thin material vertical flame test; ASTM D4804), specifically, by the method described in the examples.

[0069] <Uses> The polyimide resin composition and molded article of the present invention can be used in a wide range of applications, including, for example, sixth-generation mobile communication system (6G) related components that use 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) flexible substrates, multilayer laminates, etc. Boards, 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 radar, aerospace radar, 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.

[0070] The polyimide resin composition and molded article of the present invention have a lower melting point than the polyimide resin (A) alone, and therefore are preferable when used in a metal foil laminate in that the heat-sealing property to the metal foil is improved. Hereinafter, the metal foil laminate will be described.

[0071] [Metal Foil Laminate] The present invention provides a metal foil laminate having a layer made of a molded article containing the polyimide resin composition and a layer made of metal foil. Examples of metal foil laminates include copper-clad laminates, which may include a layer made of a film-shaped molded article containing the polyimide resin composition (hereinafter simply referred to as a "resin film layer") and at least one copper foil layer. Examples include laminates in which copper foil is laminated on at least one side, preferably both sides, of a resin film containing the polyimide resin composition.

[0072] The resin film used in producing the copper-clad laminate can be produced by the same method as the method for producing the molded article. The thickness of the resin film and the resin film layer in the copper-clad laminate is preferably 5 to 500 μm, more preferably 10 to 300 μm, and even more preferably 12.5 to 200 μm, from the viewpoint of ensuring the strength of the copper-clad laminate and improving the adhesion between the resin film layer and the copper foil layer.

[0073] The copper foil used in the manufacture of copper-clad laminates is not particularly limited; commercially available rolled copper foils, electrolytic copper foils, etc. can be used, but rolled copper foils are preferred from the standpoint of flexibility. The thickness of the copper foil layer and the copper foil used to form it is preferably 2 to 50 μm, more preferably 3 to 30 μm, and even more preferably 5 to 20 μm, from the standpoint of ensuring sufficient conductivity and improving adhesion to the resin film layer. This thickness refers to the thickness per copper foil layer or per copper foil. The surface roughness of the copper foil used in the manufacture of copper-clad laminates is not particularly limited, but the surface roughness of the copper foil is directly related to the electrical properties of the laminate itself obtained after lamination with the resin film. Generally, a lower surface roughness results in a laminate with better dielectric properties. Therefore, the maximum height roughness Rz of the copper foil surface is preferably in the range of 0.1 to 1 μm, more preferably 0.2 to 0.8 μm. The maximum height roughness Rz of the copper foil surface can be measured, for example, using a surface roughness meter.

[0074] From the viewpoint of improving the strength and conductivity of the copper-clad laminate, the thickness of the copper-clad laminate is preferably 15 to 600 μm, more preferably 25 to 500 μm, and even more preferably 50 to 300 μm. The copper-clad laminate may have any layer other than the resin film layer and the copper foil layer, as long as the effects of the present invention are not impaired.

[0075] The method for producing a copper-clad laminate is not particularly limited, and known methods can be used. For example, a lamination method can be used in which the resin film and copper foil are superimposed and then laminated under heat and pressure. Since the resin film contains a thermoplastic polyimide resin (A), the surface can be heat-melted and pressed to laminate the copper foil. The apparatus used for producing a copper-clad laminate can be any apparatus capable of laminating a resin film and a copper foil under heat and pressure, such as a roll laminator, a flat laminator, a vacuum press, or a double belt press. Among these, from the viewpoint of productivity of the copper-clad laminate and obtaining a copper-clad laminate with good appearance, a vacuum press or a double belt press is preferably used. A double belt press is an apparatus equipped with a pair of endless belts arranged above and below, in which film-shaped materials (resin film and copper foil) forming each layer are continuously fed between the belts, and the materials are heated and pressurized through the endless belt by a heating and pressurizing mechanism to produce a laminate. Examples of double belt press devices include the device described in JP 2010-221694 A and a double belt press device manufactured by Dymco Corporation.

[0076] The heating temperature when producing a copper-clad laminate by the above method is not particularly limited as long as it is a temperature that can soften or melt the resin film, but from the viewpoint of reducing the burden on the equipment and production, it is preferably in the range of 250 to 400°C, more preferably 290 to 360°C. Furthermore, the pressure conditions when producing a copper-clad laminate are preferably 0.1 to 20 MPa, more preferably 0.15 to 15 MPa, and even more preferably 0.2 to 12 MPa, from the viewpoint of improving the adhesion between the resin film and the copper foil and reducing the burden on the equipment and production. Furthermore, from the viewpoint of improving production efficiency, the pressure application time is preferably in the range of 1 to 600 seconds, more preferably 5 to 400 seconds, and even more preferably 10 to 300 seconds.

[0077] Although the resin film is characterized by its ability to be heat-sealed, it is also possible to use an adhesive to bond the resin film and copper foil together in the production of copper-clad laminates. The adhesive can be selected from a variety of adhesives, including varnish-type adhesives, sheet-type adhesives, and powder-type adhesives. From the perspective of ensuring low dielectric properties, adhesives with low dielectric properties are also preferred. Examples of adhesives with low dielectric properties include the polyimide adhesive "PIAD" series manufactured by Arakawa Chemical Industries, Ltd.

[0078] [Use] The present invention also provides use of the phosphorus-containing compound (B) represented by the following formula (5) as a crystallization rate enhancer for a crystalline thermoplastic resin. (R ５１ ~R ５４ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is -R ５５ -Z-R ５６ - is a divalent group represented by R ５５ and R ５６ are each independently a single bond or an alkylene group having 1 to 12 carbon atoms, and Z is an arylene group. n is an integer of 1 to 10. By blending the phosphorus-containing compound (B) with a crystalline thermoplastic resin, the crystallization rate of the crystalline thermoplastic resin can be improved.

[0079] The amount of the phosphorus-containing compound (B) to be blended with the crystalline thermoplastic resin is preferably 0.5 to 30 parts by mass, more preferably 0.5 to 25 parts by mass, even more preferably 1 to 20 parts by mass, still more preferably 2 to 15 parts by mass, still more preferably 3 to 15 parts by mass, still more preferably 5 to 15 parts by mass, and still more preferably 8 to 15 parts by mass, per 100 parts by mass of the crystalline thermoplastic resin.

[0080] The crystalline thermoplastic resin is not particularly limited, but is preferably a crystalline thermoplastic 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), in which the content of the repeating structural unit of formula (1) relative to the total of the repeating structural units of formula (1) and formula (2) is 15 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 having 6 to 22 carbon atoms and containing at least one aromatic ring. The polyimide resin (A), the phosphorus-containing compound (B), and preferred embodiments thereof are the same as those described above.

[0081] 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.

[0082] <Infrared Spectroscopic Analysis (IR Measurement)> IR measurement of the polyimide resin was carried out using a JEOL Ltd. "JIR-WINSPEC50".

[0083] <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 polyimide resin or polyimide resin composition were measured using a differential scanning calorimeter (TA Instruments' "DSC-25"). In each measurement, resin powder was used for the polyimide resin (Comparative Examples 1 and 2), and pellets were used for the other polyimide resin compositions. Under a nitrogen atmosphere (nitrogen gas flow rate of 50 ml / min), the measurement sample was subjected to the following thermal history conditions. The thermal history conditions were a first heating (heating rate of 10°C / min), followed by cooling (cooling rate of 20°C / min), followed by a second heating (heating rate of 10°C / min). The melting point Tm was determined by reading the peak top value of the endothermic peak observed during the second heating. The glass transition temperature Tg was determined by reading the value observed during the second heating. 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 (J / g) 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 melted again at a heating rate of 10°C / min. The heat of crystallization Hc (J / g) 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.

[0084] <Number Average Molecular Weight (Mn), Weight Average Molecular Weight (Mw)> The number average molecular weight (Mn) and weight average molecular weight (Mw) of the polyimide resin or the polyimide resin composition obtained in each example were measured under the following conditions using a gel permeation chromatography (GPC) measuring device "Shodex GPC-101" manufactured by Resonac Corporation. In each measurement, a resin powder was used as the measurement sample for the polyimide resin (Comparative Examples 1 and 2), and a pellet was used for the polyimide resin composition. Column: Shodex HFIP-806M Mobile phase solvent: 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

[0085] <Flame Retardancy> Using the polyimide resin or the polyimide resin composition obtained in each example, a molded article (film) measuring 200 mm x 50 mm x 0.05±0.01 mm thick was prepared by the method described below. The film was conditioned at 23±2°C and 50±5% RH for 48 hours, and then used in a UL94VTM test (thin material vertical flame test; ASTM D4804) under the following test environment: 25±10°C and 75% RH.

[0086] (Total Flaming Burning Time) The film was rolled into a cylindrical shape and attached vertically to a clamp, and exposed to a 20 mm high flame using methane gas for 3 seconds twice. The total flaming burning time (seconds) (n=5) is shown in Table 2. A shorter total time indicates better flame retardancy.

[0087] (Whether or not flame reached the 125 mm mark) The film was observed for whether or not flame reached the 125 mm mark from the bottom end, and the number of times that flame reached the 125 mm mark out of five tests is shown in Table 2. A smaller number of times indicates better flame retardancy.

[0088] (Whether or not cotton caught fire) In the above combustion test, the presence or absence of ignition by dripping on cotton placed 300 mm below the film was observed. The number of times that the cotton caught fire out of five tests is shown in Table 2. If the cotton never caught fire, it was recorded as "none". A lower number of ignitions indicates a higher drip prevention effect and better flame retardancy.

[0089] (Determination of Flame Retardancy) Flame retardancy rank was determined based on the UL94VTM criteria. In Table 2, if the flame retardancy was equivalent to VTM-0 according to the UL94VTM criteria, it was indicated as "VTM-0 equivalent," if the flame retardancy was equivalent to VTM-1, it was indicated as "VTM-1 equivalent," and if the flame retardancy was equivalent to VTM-2, it was indicated as "VTM-2 equivalent." Flame retardancy increases in the order of VTM-0 > 1 > 2, and if the flame retardancy did not reach VTM-2 equivalent, it was indicated as "VTM non-compliant."

[0090] Production Example 1 (Production of Polyimide Resin 1) 600 g of 2-(2-methoxyethoxy)ethanol (manufactured by Nippon Nyukazai Co., Ltd.) and 218.58 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, 49.42 g (0.347 mol) of 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., cis / trans ratio = 7 / 3) and 93.16 g (0.645 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 to the flask 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. Nitrogen flow was maintained throughout the dropwise addition of the mixed diamine solution, 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 1.934 g (0.00149 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 316 g of powder of polyimide resin 1. When the IR spectrum of polyimide resin 1 was measured, it was found that ν(C═O) 1768, 1697 (cm －１ The melting point (Tm) was 319°C, the glass transition temperature (Tg) was 184°C, the crystallization temperature (Tc) was 266°C, the heat of fusion (Hm) was 28 J / g, the heat of crystallization (Hc) was 30 J / g, and the Mw was 39,800.

[0091] 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 to the flask 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 1.541 g (0.012 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 120 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 a powder of crystalline thermoplastic polyimide resin 2 (hereinafter also simply referred to as "polyimide resin 2"). The IR spectrum of polyimide resin 2 was measured, and it was found to have a ν(C=O) 1768, 1697 (cm －１ The melting point (Tm) was 344°C, the glass transition temperature (Tg) was 160°C, the crystallization temperature (Tc) was 295°C, the heat of fusion (Hm) was 38 J / g, the heat of crystallization (Hc) was 37 J / g, and the Mw was 45,000.

[0092] The compositions of the polyimide resins in the production examples 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 is produced.

[0093]

[0094] 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

[0095] Examples 1 to 6 (Production and Evaluation of Polyimide Resin Composition and Molded Article (Resin Film)) The crystalline thermoplastic polyimide resin (A) obtained in Production Example 1 or 2 and the phosphorus-containing compound (B) shown in Table 2 were thoroughly mixed by dry blending. The resulting mixed powder was extruded into strands having a diameter of 2 to 3 mm using a co-rotating twin-screw kneading extruder ("HK-25D-41D" manufactured by Parker Corporation) at a barrel temperature of 350°C and a screw rotation speed of 200 rpm for Examples 2 to 4, and a small twin-screw extruder at a barrel temperature of 360°C and a screw rotation speed of 100 rpm for Examples 1, 5, and 6. The strands extruded from the extruder were air-cooled and then pelletized using a pelletizer ("Fan Cutter FC-Mini-4 / N" manufactured by Hoshi Plastics Co., Ltd.). For Examples 2 to 4, the resulting pellets (polyimide resin composition) were dried at 190°C for 10 hours and then used for extrusion molding using the method described below. The pellets were placed in a Φ20 mm single-screw extruder equipped with a 150 mm wide T-die, melt-kneaded at a resin temperature of 340 to 360°C, and continuously extruded from the T-die of the single-screw extruder. The mixture was then cooled with a metal cooling roll at 140°C to obtain a resin film with a thickness of 0.05±0.01 mm. The temperature of the Φ20 mm single-screw extruder was adjusted to 340 to 355°C, and the temperature of the T-die was adjusted to 350°C. The resulting pellets (polyimide resin composition) or the prepared resin film were subjected to various evaluations using the methods described above. The results are shown in Table 2.

[0096] Comparative Example 1: The powder of polyimide resin 1 obtained in Production Example 1 was extruded into strands with a diameter of 2 to 3 mm using a co-rotating twin-screw kneading extruder ("HK-25D-41D" manufactured by Parker Corporation) at a barrel temperature of 350°C and a screw rotation speed of 120 rpm. The strands extruded from the extruder were 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 190°C for 10 hours and then used for extrusion molding. The pellets were fed into a Φ20 mm single-screw extruder equipped with a 150 mm wide T-die, melt-kneaded at a resin temperature of 340 to 360°C, and continuously extruded from the T-die of the single-screw extruder. The resulting resin was then cooled with a metal chill roll at 140°C to obtain a resin film with a thickness of 0.05±0.01 mm. The temperature of the 20 mm diameter single-screw extruder was adjusted to 340 to 355°C, and the temperature of the T-die was adjusted to 350°C. The powder of polyimide resin 1 obtained in Production Example 1 or the prepared resin film was used to carry out various evaluations using the methods described above. The results are shown in Table 2.

[0097] Comparative Example 2 The powder of polyimide resin 2 obtained in Production Example 2 was used to carry out various evaluations by the methods described above. The results are shown in Table 2.

[0098]

[0099] Details of each component shown in Table 2 are as follows: <Crystalline thermoplastic polyimide resin (A)> Polyimide resin 1 obtained in Production Example 1 Polyimide resin 2 obtained in Production Example 2 <Phosphorus-containing compound (B)> Compound represented by the following structural formula (1,4-bis[(diphenylphosphoroso)methyl]benzene), manufactured by Aurora Fine Chemicals, melting point: 336°C, 5% decomposition temperature (measured at a heating rate of 10°C / min under a nitrogen atmosphere): 401°C

[0100] A comparison of Comparative Example 1 with Examples 1 to 5 and a comparison of Comparative Example 2 with Example 6 in Table 2 reveals that the polyimide resin compositions of the present invention have a lower Tm-Tc value than the polyimide resin alone, i.e., an improved crystallization rate. Furthermore, the polyimide resin compositions of Examples 1 to 6 show less molecular weight reduction even when subjected to thermal melting than the polyimide resin alone. A comparison of Comparative Example 1 with Examples 2 to 4 reveals that the molded articles of Examples 2 to 4 containing the polyimide resin compositions of the present invention also have improved flame retardancy compared to the molded article of Comparative Example 1.

[0101] According to the present invention, it is possible to provide a polyimide resin composition containing a crystalline thermoplastic polyimide resin of a predetermined structure and having a crystallization rate improved compared to that of the resin alone, a molded article containing the same, a method for producing the same, and a metal foil laminate.

Claims

1. A polyimide resin composition comprising: a crystalline thermoplastic 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), in which the content of the repeating structural unit of the formula (1) relative to the total of the repeating structural units of the formula (1) and the repeating structural units of the formula (2) is 15 to 70 mol %; and a phosphorus-containing compound (B) represented by the following formula (5). (R １ R 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 having 6 to 22 carbon atoms and containing at least one aromatic ring. (R ５１ ~R ５４ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is -R ５５ -Z-R ５６ R is a divalent group represented by the formula: ５５ and R ５６ are each independently a single bond or an alkylene group having 1 to 12 carbon atoms, and Z is an arylene group. n is an integer of 1 to 10.

2. The polyimide resin composition according to claim 1, wherein the content of the phosphorus-containing compound (B) in the polyimide resin composition is 0.5 to 30 parts by mass per 100 parts by mass of the crystalline thermoplastic polyimide resin (A).

3. The polyimide resin composition according to claim 1 or 2, wherein the total content of the crystalline thermoplastic polyimide resin (A) and the phosphorus-containing compound (B) in the polyimide resin composition is 50 mass% or more.

4. In the formula (5), R ５１ ~R ５４ The polyimide resin composition according to any one of claims 1 to 3, wherein is a phenyl group, and n is 1.

5. The polyimide resin composition according to any one of claims 1 to 4, wherein Tm - Tc is 50°C or less, where Tm (°C) is the melting point of a pellet made of the polyimide resin composition and Tc (°C) is the crystallization temperature.

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

7. A method for producing a molded article, comprising the step of melt-kneading the polyimide resin composition according to any one of claims 1 to 5 at a temperature exceeding the melting point of the phosphorus-containing compound (B).

8. A metal foil laminate comprising a layer of the molded article according to claim 6 and a layer of metal foil.

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