WO2025028162A1 - Polyimide resin composition, molded body and method for producing same, and metal foil laminate - Google Patents

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 same, and metal foil laminate

The present invention relates to a polyimide resin composition, a molded body and its manufacturing method, and a metal foil laminate.

Polyimide resins are useful engineering plastics that have high thermal stability, high strength, and high 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.
Although polyimide resins have high heat resistance, they do not exhibit thermoplasticity and have the problem of low moldability. However, in recent years, polyimide resins with thermoplasticity have been reported. Thermoplastic polyimide resins have excellent moldability in addition to the heat resistance that polyimide resins inherently have. Therefore, thermoplastic polyimide resins can be used for molded products used in harsh environments where general-purpose thermoplastic resins such as nylon and polyester could not be used.

Among thermoplastic resins, crystalline thermoplastic resins have a melting point and exhibit fluidity at high temperatures, and therefore can be molded easily and inexpensively.
In thermoforming of a resin material containing a crystalline thermoplastic resin, it is important to control the crystallization rate of the resin. For example, Patent Document 1 proposes a resin composition containing a liquid crystal polymer of a predetermined structure and a polyimide resin for the purpose of improving the handleability during melt molding of a liquid crystal polymer, which has a high crystallization rate and a low elasticity when melted.

International Publication No. 2022/004471

Since the liquid crystal polymer used in the technology disclosed in Patent Document 1 has a high crystallization rate, the crystallization rate is reduced to improve the handleability during melt molding. In contrast, 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.
An object of the present invention is to provide a polyimide resin composition containing a crystalline thermoplastic polyimide resin of a predetermined structure and having a crystallization rate improved as compared with that of the resin alone, a molded article containing the same and a method for producing the same, and a metal foil laminate.

（Ｒ_１は少なくとも１つの脂環式炭化水素構造を含む炭素数６～２２の２価の基である。Ｒ_２は炭素数５～１６の２価の鎖状脂肪族基である。Ｘ_１及びＸ_２は、それぞれ独立に、少なくとも１つの芳香環を含む炭素数６～２２の４価の基である。）

（Ｒ_５１～Ｒ_５４はそれぞれ独立に、炭素数１～１２の炭化水素基である。Ｙは－Ｒ_５５－Ｚ－Ｒ_５６－で示される２価の基である。Ｒ_５５及びＲ_５６はそれぞれ独立に、単結合又は炭素数１～１２のアルキレン基であり、Ｚはアリーレン基である。ｎは１～１０の整数である。）
［２］前記ポリイミド樹脂組成物中の前記リン含有化合物（Ｂ）の含有量が、前記結晶性熱可塑性ポリイミド樹脂（Ａ）１００質量部に対し０．５～３０質量部である、［１］に記載のポリイミド樹脂組成物。
［３］前記ポリイミド樹脂組成物中の前記結晶性熱可塑性ポリイミド樹脂（Ａ）及び前記リン含有化合物（Ｂ）の合計含有量が５０質量％以上である、［１］又は［２］に記載のポリイミド樹脂組成物。
［４］前記式（５）において、Ｒ_５１～Ｒ_５４がフェニル基であり、ｎが１である、［１］～［３］のいずれか１項に記載のポリイミド樹脂組成物。
［５］前記ポリイミド樹脂組成物からなるペレットの融点をＴｍ（℃）、結晶化温度をＴｃ（℃）とした場合に、Ｔｍ－Ｔｃが５０℃以下である、［１］～［４］のいずれか１項に記載のポリイミド樹脂組成物。
［６］［１］～［５］のいずれか１項に記載のポリイミド樹脂組成物を含む成形体。
［７］［１］～［５］のいずれか１項に記載のポリイミド樹脂組成物を、前記リン含有化合物（Ｂ）の融点を超える温度で溶融混練する工程を含む、成形体の製造方法。
［８］［６］に記載の成形体からなる層と、金属箔からなる層とを有する、金属箔積層板。 The present inventors have found that the above-mentioned problems can be solved by a polyimide resin composition containing a polyimide resin in which specific different polyimide structural units are combined in a specific ratio, and a phosphorus-containing compound having a specific structure.
That is, the present invention relates to the following.
[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).

( _R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. _R2 is a divalent chain aliphatic group having 5 to 16 carbon atoms. _X1 and _X2 are each independently a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.)

(R ₅₁ to R ₅₄ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is a divalent group represented by -R ₅₅ -Z-R ₅₆ -. 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 from 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 mass% or more.
[4] The polyimide resin composition according to any one of [1] to [3], wherein in the formula (5), R ₅₁ to R ₅₄ are phenyl groups 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 product according to [6] and a layer made of metal foil.

The present invention provides a polyimide resin composition that contains a crystalline thermoplastic polyimide resin of a specific structure and has a crystallization rate that is faster than that of the resin alone, a molded article that contains the polyimide resin composition, a method for producing the molded article, and a metal foil laminate.

[Definition]
In this specification, the term "crystalline thermoplastic polyimide resin" refers to a polyimide resin that has both a melting point and a glass transition temperature.
In this specification, whether or not the crystallization rate of the polyimide resin composition of the present invention is improved compared to that of the crystalline thermoplastic polyimide resin (A) alone is judged 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 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 by a differential scanning calorimeter according to the method described in the Examples.

（Ｒ_１は少なくとも１つの脂環式炭化水素構造を含む炭素数６～２２の２価の基である。Ｒ_２は炭素数５～１６の２価の鎖状脂肪族基である。Ｘ_１及びＸ_２は、それぞれ独立に、少なくとも１つの芳香環を含む炭素数６～２２の４価の基である。）

（Ｒ_５１～Ｒ_５４はそれぞれ独立に、炭素数１～１２の炭化水素基である。Ｙは－Ｒ_５５－Ｚ－Ｒ_５６－で示される２価の基である。Ｒ_５５及びＲ_５６はそれぞれ独立に、単結合又は炭素数１～１２のアルキレン基であり、Ｚはアリーレン基である。ｎは１～１０の整数である。） [Polyimide resin composition]
The polyimide resin composition of the present invention contains a crystalline thermoplastic polyimide resin (A) which 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 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).

( _R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. _R2 is a divalent chain aliphatic group having 5 to 16 carbon atoms. _X1 and _X2 are each independently a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.)

(R ₅₁ to R ₅₄ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is a divalent group represented by -R ₅₅ -Z-R ₅₆ -. 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 from 1 to 10.)

The polyimide resin composition of the present invention is a resin composition in which a crystalline thermoplastic polyimide resin (A) (hereinafter also simply referred to as "polyimide resin (A)") obtained by combining specific different polyimide constituent units in the above-mentioned specific ratio and a specific phosphorus-containing compound (B) (hereinafter also simply referred to as "compound (B)") are combined, thereby improving the crystallization rate compared to the case of polyimide resin (A) alone.
The reason why the above-mentioned effects are obtained in the present invention is not clear, but is thought to be as follows.
In general, a crystal nucleating agent is used to increase 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, and in that case, it is considered that the effect of increasing the crystallization temperature Tc of the resulting resin composition is exerted.
In some cases, an inorganic compound is used as a crystal nucleating agent. Inorganic compounds usually have no melting point or a high melting point exceeding 400°C, but since the compound (B) is an organic compound having a melting point equal to or lower than that of the crystalline thermoplastic polyimide resin (A), adding the compound (B) to the 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 the crystalline thermoplastic polyimide resin (A) alone, and it is considered that the crystallization rate is improved.

Furthermore, by containing both polyimide resin (A) and compound (B), the polyimide resin composition of the present invention can suppress the molecular weight reduction of polyimide resin (A) during melt-kneading and achieve high flame retardancy. The reason for this is assumed to be that crosslinks are formed between polyimide resin (A) and compound (B) during melt-kneading to the extent that does not impair fluidity during melting, which is believed to provide the effect of suppressing molecular weight reduction and the effect of improving flame retardancy. Compound (B) is also a highly flame-retardant phosphorus-atom-containing compound, and has the characteristic of being highly heat-resistant since it does not have an ester structure. Therefore, when compound (B) is added to 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 a temperature above the melting point of polyimide resin (A), and is believed to have a high effect of improving flame retardancy.

（Ｒ_１は少なくとも１つの脂環式炭化水素構造を含む炭素数６～２２の２価の基である。Ｒ_２は炭素数５～１６の２価の鎖状脂肪族基である。Ｘ_１及びＸ_２は、それぞれ独立に、少なくとも１つの芳香環を含む炭素数６～２２の４価の基である。） <Crystalline Thermoplastic Polyimide Resin (A)>
The crystalline thermoplastic polyimide resin (A) used in the present invention contains a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and the content of the repeating unit of the formula (1) relative to the total of the repeating unit of the formula (1) and the repeating unit of the formula (2) is 15 to 70 mol %.

( _R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. _R2 is a divalent chain aliphatic group having 5 to 16 carbon atoms. _X1 and _X2 are each independently a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.)

The polyimide resin (A) used in the present invention is a crystalline thermoplastic resin, and is preferably in the form of a powder or pellets. Thermoplastic polyimide resins are formed, for example, 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 polyimide resins that decompose at a temperature lower than the glass transition temperature.

The repeating unit of formula (1) is described in detail below.
_R1 is a divalent group containing at least one alicyclic hydrocarbon structure and having 6 to 22 carbon atoms. Here, the alicyclic hydrocarbon structure means 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 the alicyclic hydrocarbon structure include, but are not limited to, a cycloalkane ring such as a cyclohexane ring, a cycloalkene ring such as a cyclohexene ring, a bicycloalkane ring such as a norbornane ring, and a bicycloalkene ring 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.
_R1 has 6 to 22 carbon atoms, and preferably 8 to 17 carbon atoms.
_R1 contains at least one alicyclic hydrocarbon structure, and preferably contains 1 to 3 alicyclic hydrocarbon structures.

（ｍ_１１及びｍ_１２は、それぞれ独立に、０～２の整数であり、好ましくは０又は１である。ｍ_１３～ｍ_１５は、それぞれ独立に、０～２の整数であり、好ましくは０又は１である。） R ₁ is preferably a divalent group represented by the following formula (R1-1) or (R1-2).

( _m11 and _m12 each independently represent an integer of 0 to 2, preferably 0 or 1. _m13 to _m15 each independently represent an integer of 0 to 2, preferably 0 or 1.)

　なお、上記の式（Ｒ１－３）で表される２価の基において、２つのメチレン基のシクロヘキサン環に対する位置関係はシスであってもトランスであってもよく、またシスとトランスの比は如何なる値でもよい。 _R1 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 to the cyclohexane ring may be either cis or trans, and the ratio of cis to trans may be any value.

_X1 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, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a tetracene ring. Among these, a benzene ring and a naphthalene ring are preferred, and a benzene ring is more preferred.
_X1 has 6 to 22 carbon atoms, and preferably 6 to 18 carbon atoms.
_X1 contains at least one aromatic ring, and preferably contains 1 to 3 aromatic rings.

（Ｒ_１１～Ｒ_１８は、それぞれ独立に、炭素数１～４のアルキル基である。ｐ_１１～ｐ_１３は、それぞれ独立に、０～２の整数であり、好ましくは０である。ｐ_１４、ｐ_１５、ｐ_１６及びｐ_１８は、それぞれ独立に、０～３の整数であり、好ましくは０である。ｐ_１７は０～４の整数であり、好ましくは０である。Ｌ_１１～Ｌ_１３は、それぞれ独立に、単結合、エーテル基、カルボニル基又は炭素数１～４のアルキレン基である。）
　なお、Ｘ_１は少なくとも１つの芳香環を含む炭素数６～２２の４価の基であるので、式（Ｘ－２）におけるＲ_１２、Ｒ_１３、ｐ_１２及びｐ_１３は、式（Ｘ－２）で表される４価の基の炭素数が１０～２２の範囲に入るように選択される。
　同様に、式（Ｘ－３）におけるＬ_１１、Ｒ_１４、Ｒ_１５、ｐ_１４及びｐ_１５は、式（Ｘ－３）で表される４価の基の炭素数が１２～２２の範囲に入るように選択され、式（Ｘ－４）におけるＬ_１２、Ｌ_１３、Ｒ_１６、Ｒ_１７、Ｒ_１８、ｐ_１６、ｐ_１７及びｐ_１８は、式（Ｘ－４）で表される４価の基の炭素数が１８～２２の範囲に入るように選択される。 _X1 is preferably a tetravalent group represented by any one of the following formulas (X-1) to (X-4).

(R ₁₁ to R ₁₈ are each independently an alkyl group having 1 to 4 carbon atoms. _{p 11} to p ₁₃ are each independently an integer of 0 to 2, preferably 0. p ₁₄ , p ₁₅ , p ₁₆ and p ₁₈ are each independently an integer of 0 to 3, preferably 0. p ₁₇ is an integer of 0 to 4, preferably 0. _{L 11} to L ₁₃ are each independently a single bond, an ether group, a carbonyl group or an alkylene group having 1 to 4 carbon atoms.)
Since _X1 is a tetravalent group containing at least one aromatic ring and having 6 to 22 carbon atoms, _R12 , _R13 , _p12 , and _p13 in formula (X-2) are 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 ₁₁ , R ₁₄ , R ₁₅ , p ₁₄ and p ₁₅ in formula (X-3) are selected so that the number of carbon atoms in the tetravalent group represented by formula (X-3) falls within the range of 12 to 22, and L ₁₂ , L ₁₃ , R 16 , R ₁₇ , R ₁₈ , p ₁₆ , p ₁₇ and p ₁₈ in formula (X-4) are 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.

_X1 is particularly preferably a tetravalent group represented by the following formula (X-5) or (X-6).

Next, the repeating unit of formula (2) will be described in detail below.
_R2 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, may be linear or branched, and may contain a heteroatom such as an oxygen atom.
_R2 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 particularly preferably an alkylene group having 8 to 10 carbon atoms. The alkylene group may be a linear alkylene group or a branched alkylene group, but is preferably a linear alkylene group.
_R2 is preferably at least one selected from the group consisting of an octamethylene group and a decamethylene group, and particularly preferably an octamethylene group.

（ｍ_２１及びｍ_２２は、それぞれ独立に、１～１５の整数であり、好ましくは１～１３、より好ましくは１～１１、更に好ましくは１～９である。ｍ_２３～ｍ_２５は、それぞれ独立に、１～１４の整数であり、好ましくは１～１２、より好ましくは１～１０、更に好ましくは１～８である。）
　なお、Ｒ_２は炭素数５～１６（好ましくは炭素数６～１４、より好ましくは炭素数７～１２、更に好ましくは炭素数８～１０）の２価の鎖状脂肪族基であるので、式（Ｒ２－１）におけるｍ_２１及びｍ_２２は、式（Ｒ２－１）で表される２価の基の炭素数が５～１６（好ましくは炭素数６～１４、より好ましくは炭素数７～１２、更に好ましくは炭素数８～１０）の範囲に入るように選択される。すなわち、ｍ_２１＋ｍ_２２は５～１６（好ましくは６～１４、より好ましくは７～１２、更に好ましくは８～１０）である。
　同様に、式（Ｒ２－２）におけるｍ_２３～ｍ_２５は、式（Ｒ２－２）で表される２価の基の炭素数が５～１６（好ましくは炭素数６～１４、より好ましくは炭素数７～１２、更に好ましくは炭素数８～１０）の範囲に入るように選択される。すなわち、ｍ_２３＋ｍ_２４＋ｍ_２５は５～１６（好ましくは炭素数６～１４、より好ましくは炭素数７～１２、更に好ましくは炭素数８～１０）である。 Another preferred embodiment of _R2 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.

( _m21 and _m22 each independently represent an integer of 1 to 15, preferably 1 to 13, more preferably 1 to 11, and even more preferably 1 to 9. _m23 to _m25 each independently represent an integer of 1 to 14, preferably 1 to 12, more preferably 1 to 10, and even more preferably 1 to 8.)
Since R 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), m ₂₁ and m ₂₂ in formula (R2-1) are 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). In other words, m ₂₁ +m ₂₂ is 5 to 16 (preferably 6 to 14, more preferably 7 to 12, and even more preferably 8 to 10).
Similarly, m ₂₃ to m ₂₅ in formula (R2-2) are 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). In other words, m ₂₃ + m ₂₄ + m ₂₅ is 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).

_X2 is defined in the same manner as _X1 in formula (1), and the preferred embodiments are also the same.

The content ratio of the repeating structural unit of formula (1) to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) is 15 to 70 mol %. When the content ratio of the repeating structural unit of formula (1) is within the above range, it becomes possible to sufficiently crystallize the polyimide resin even in a general injection molding cycle. If the content ratio is less than 15 mol %, the moldability decreases, and if it exceeds 70 mol %, the crystallinity decreases, and therefore the heat resistance decreases.
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 preferably 65 mol % or less, more preferably 60 mol % or less, even more preferably 50 mol % or less, still more preferably less than 40 mol %, from the viewpoint of expressing high crystallinity, and even more preferably 35 mol % or less.
From the viewpoint of moldability, the content is preferably 20 mol % or more.

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

（Ｒ_３は少なくとも１つの芳香環を含む炭素数６～２２の２価の基である。Ｘ_３は少なくとも１つの芳香環を含む炭素数６～２２の４価の基である。） The polyimide resin (A) may further contain a repeating unit of the following formula (3). In this case, the content ratio of the repeating unit of the formula (3) to the total of the repeating unit of the formula (1) and the repeating unit of the formula (2) is preferably 25 mol% or less. On the other hand, the lower limit is not particularly limited, and it is sufficient that it is more 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.

( _R3 is a divalent group having 6 to 22 carbon atoms containing at least one aromatic ring. _X3 is a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.)

_R3 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, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a tetracene ring. Among these, a benzene ring and a naphthalene ring are preferred, and a benzene ring is more preferred.
_R3 has 6 to 22 carbon atoms, and preferably 6 to 18 carbon atoms.
_R3 contains at least one aromatic ring, and preferably contains 1 to 3 aromatic rings.
Furthermore, a monovalent or divalent electron-withdrawing group may be bonded to the aromatic ring. Examples of the monovalent electron-withdrawing group include a nitro group, a cyano group, a p-toluenesulfonyl group, a halogen, a halogenated alkyl group, a phenyl group, and an acyl group. Examples of the divalent electron-withdrawing group include a halogenated alkylene group such as a fluorinated alkylene group (e.g., -C(CF ₃ ) ₂ -, -(CF ₂ ) _p - (wherein p is an integer of 1 to 10)), as well as -CO-, -SO ₂ -, -SO-, -CONH-, -COO-, and the like.

（ｍ_３１及びｍ_３２は、それぞれ独立に、０～２の整数であり、好ましくは０又は１である。ｍ_３３及びｍ_３４は、それぞれ独立に、０～２の整数であり、好ましくは０又は１である。Ｒ_２１、Ｒ_２２、及びＲ_２３は、それぞれ独立に、炭素数１～４のアルキル基、炭素数２～４のアルケニル基、又は炭素数２～４のアルキニル基である。ｐ_２１、ｐ_２２及びｐ_２３は０～４の整数であり、好ましくは０である。Ｌ_２１は、単結合、エーテル基、カルボニル基又は炭素数１～４のアルキレン基である。）
　なお、Ｒ_３は少なくとも１つの芳香環を含む炭素数６～２２の２価の基であるので、式（Ｒ３－１）におけるｍ_３１、ｍ_３２、Ｒ_２１及びｐ_２１は、式（Ｒ３－１）で表される２価の基の炭素数が６～２２の範囲に入るように選択される。
　同様に、式（Ｒ３－２）におけるＬ_２１、ｍ_３３、ｍ_３４、Ｒ_２２、Ｒ_２３、ｐ_２２及びｐ_２３は、式（Ｒ３－２）で表される２価の基の炭素数が１２～２２の範囲に入るように選択される。 _R3 is preferably a divalent group represented by the following formula (R3-1) or (R3-2).

( _m31 and _m32 each independently represent an integer of 0 to 2, preferably 0 or 1. _m33 and _m34 each independently represent an integer of 0 to 2, preferably 0 or 1. _R21 , _R22 , and R23 each independently represent 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. _p21 , _p22 , and _{p23 each} independently represent an integer of 0 to 4, preferably 0. _L21 represents a single bond, an ether group, a carbonyl group, or an alkylene group having 1 to 4 carbon atoms.)
Since R ₃ is a divalent group containing at least one aromatic ring and having 6 to 22 carbon atoms, m ₃₁ , m ₃₂ , R ₂₁ and p ₂₁ in formula (R3-1) are selected so that the divalent group represented by formula (R3-1) has a carbon number in the range of 6 to 22.
Similarly, L ₂₁ , m ₃₃ , m ₃₄ , R ₂₂ , R ₂₃ , p ₂₂ and p ₂₃ in formula (R3-2) are selected so that the divalent group represented by formula (R3-2) has 12 to 22 carbon atoms.

_X3 is defined in the same manner as _X1 in formula (1), and the preferred embodiments are also the same.

（Ｒ_４は－ＳＯ_２－又は－Ｓｉ（Ｒ_ｘ）（Ｒ_ｙ）Ｏ－を含む２価の基であり、Ｒ_ｘ及びＲ_ｙはそれぞれ独立に、炭素数１～３の鎖状脂肪族基又はフェニル基を表す。Ｘ_４は少なくとも１つの芳香環を含む炭素数６～２２の４価の基である。）
　Ｘ_４は、式（１）におけるＸ_１と同様に定義され、好ましい様態も同様である。 The polyimide resin (A) may further contain a repeating unit represented by the following formula (4).

(R ₄ is a divalent group containing -SO ₂ - or -Si(R _x )(R _y )O-, and R _x and R _y each independently represent a chain aliphatic group having 1 to 3 carbon atoms or a phenyl group. X ₄ is a tetravalent group containing at least one aromatic ring and having 6 to 22 carbon atoms.)
_X4 is defined in the same manner as _X1 in formula (1), and the preferred embodiments are also the same.

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 specific group at its terminal, a resin composition having excellent heat aging resistance can be obtained.
Examples of the saturated chain aliphatic group 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 the unsaturated chain aliphatic group having 5 to 14 carbon atoms include a 1-pentenyl group, a 2-pentenyl group, a 1-hexenyl group, a 2-hexenyl group, a 1-heptenyl group, a 2-heptenyl group, a 1-octenyl group, a 2-octenyl group, a nonenyl group, a decenyl group, a dodecenyl group, a tridecenyl group, and a tetradecenyl group.
Among them, the chain aliphatic group is preferably a saturated chain aliphatic group, more preferably a saturated linear chain aliphatic group. From the viewpoint of obtaining heat aging resistance, the chain aliphatic group preferably has 6 or more carbon atoms, more preferably 7 or more carbon atoms, even more preferably 8 or more carbon atoms, and preferably has 12 or less carbon atoms, more preferably 10 or less carbon atoms, even more preferably 9 or less carbon atoms. The chain aliphatic group may be of only one kind or of two or more kinds.
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 terminal, only a chain aliphatic group having 5 to 14 carbon atoms, in addition to a terminal amino group and a terminal carboxy group. When the polyimide resin (A) has a group other than the above at its terminal, the content thereof is preferably 10 mol % or less, more preferably 5 mol % or less, based on the chain aliphatic group having 5 to 14 carbon atoms.

The content of the chain aliphatic group 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 units constituting the polyimide resin (A). When the content of the chain aliphatic group 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 units constituting the polyimide resin (A), excellent heat aging resistance is exhibited, and when it is 10 mol % or less, a sufficient molecular weight is ensured and good mechanical properties are obtained.
The term "total of all repeating units constituting the polyimide resin (A)" used herein means the total of the repeating units represented by the above formulas (1), (2), (3) and (4).
The content of the chain aliphatic group having 5 to 14 carbon atoms in the polyimide resin (A) can be determined by depolymerizing the polyimide resin (A).

The polyimide resin (A) preferably has a melting point of 360° C. or less and a glass transition temperature of 150° C. or more. From the viewpoint of heat resistance, the melting point Tm of the polyimide resin (A) is preferably 270° C. or more, more preferably 280° C. or more, even more preferably 290° C. or more, still more preferably 300° C. or more, still more preferably 310° C. or more, and still more preferably 315° C. or more, and from the viewpoint of exhibiting high moldability, it is preferably 345° C. or less.
From the viewpoint of achieving 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.

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.

From the viewpoints of crystallinity, heat resistance, mechanical strength, and chemical resistance, the polyimide resin (A) has a heat of fusion Hm of preferably 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 from the area of the heat of fusion peak (endothermic peak) near the melting point observed when the polyimide resin (A) is heated at a heating rate of 10° C./min to melt at a temperature equal to or higher than 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, by differential scanning calorimeter measurement.

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) means the heat of the exothermic crystallization peak observed when the polyimide resin (A) is melted and then cooled at a temperature decreasing rate of 20° C./min, as measured by 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 method described in the Examples.

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 obtained molded article becomes good, and if it is 150,000 or less, the moldability becomes 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.

(Method for producing polyimide resin (A))
The polyimide resin (A) can be produced by reacting a tetracarboxylic acid component containing at least one aromatic ring-containing tetracarboxylic acid and/or a derivative thereof with a diamine component containing at least one alicyclic hydrocarbon structure and a chain aliphatic diamine.

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. As the tetracarboxylic acid, pyromellitic acid, 2,3,5,6-toluenetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, etc. are preferred. Among these, pyromellitic acid is more preferred.

Examples of derivatives of tetracarboxylic acids containing at least one aromatic ring include anhydrides or alkyl esters of tetracarboxylic acids containing at least one aromatic ring. The tetracarboxylic acid derivatives preferably have 6 to 38 carbon atoms. Examples of anhydrides of tetracarboxylic acids include pyromellitic monoanhydride, pyromellitic dianhydride, 2,3,5,6-toluenetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 1,4,5,8-naphthalenetetracarboxylic 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, and dimethyl 1,4,5,8-naphthalenetetracarboxylate. In the alkyl esters of the above tetracarboxylic acids, the alkyl group preferably has 1 to 3 carbon atoms.

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

The number of carbon atoms of the diamine containing at least one alicyclic hydrocarbon structure is preferably 6 to 22, 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. These compounds may be used alone, or two or more compounds selected from these may be used in combination. Among these, 1,3-bis(aminomethyl)cyclohexane is preferably used. Diamines containing an alicyclic hydrocarbon structure generally have structural isomers, but the ratio of cis/trans isomers is not limited.

The chain aliphatic diamine may be linear or branched, and preferably has a carbon number of 5 to 16, more preferably 6 to 14, and even more preferably 7 to 12. In addition, when the number of carbon atoms in the chain portion is 5 to 16, an ether bond may be contained therein. As the chain aliphatic diamine, for example, 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, 2,2'-(ethylenedioxy)bis(ethyleneamine), and the like are preferred.
The chain aliphatic diamine may be used alone or in combination of two or more. Among these, a chain aliphatic diamine having 8 to 10 carbon atoms is preferably used, and in particular, at least one selected from the group consisting of 1,8-octamethylenediamine and 1,10-decamethylenediamine is preferably used.

When producing polyimide resin (A), the molar ratio of the amount of diamine containing at least one alicyclic hydrocarbon structure charged to the total amount of diamine containing at least one alicyclic hydrocarbon structure and chain aliphatic diamine is preferably 15 to 70 mol%. The molar amount is preferably 20 mol% or more, and from the viewpoint of expressing 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.

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 orthoxylylenediamine, metaxylylenediamine, paraxylylenediamine, 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.

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 more 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.
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 still more preferably 0 mol %.

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

When producing the polyimide resin (A), a terminal blocking agent may be mixed in addition to the tetracarboxylic acid component and the diamine component. The terminal blocking agent is preferably at least one selected from the group consisting of monoamines and dicarboxylic acids. The amount of the terminal blocking agent used may be any amount that allows a desired amount of terminal groups to be introduced 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, as the end-capping agent, a monoamine end-capping agent is preferable, and from the viewpoint of improving heat aging resistance by introducing the above-mentioned chain aliphatic group having 5 to 14 carbon atoms into the end of the polyimide resin (A), a monoamine having a chain aliphatic group having 5 to 14 carbon atoms is more preferable, and a monoamine having a saturated linear aliphatic group having 5 to 14 carbon atoms is even more preferable.
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, further 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.

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

From the viewpoint of obtaining the effects of the present invention, the content of 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, even more preferably 80% by mass or more, even more preferably 88% by mass or more, and preferably 99.5% by mass or less.

（Ｒ_５１～Ｒ_５４はそれぞれ独立に、炭素数１～１２の炭化水素基である。Ｙは－Ｒ_５５－Ｚ－Ｒ_５６－で示される２価の基である。Ｒ_５５及びＲ_５６はそれぞれ独立に、単結合又は炭素数１～１２のアルキレン基であり、Ｚはアリーレン基である。ｎは１～１０の整数である。） <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 higher than that of the polyimide resin (A) alone can be obtained.

(R ₅₁ to R ₅₄ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is a divalent group represented by -R ₅₅ -Z-R ₅₆ -. 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 from 1 to 10.)

In formula (5), the hydrocarbon group having 1 to 12 carbon atoms for R ₅₁ to R ₅₄ 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 preferably a phenyl group.

In formula (5), Y is a divalent group represented by -R ₅₅ -Z-R ₅₆ -, and 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.

In the divalent group represented by -R ₅₅ -Z-R ₅₆ -, 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 preferable, and a 1,4-phenylene group is more preferable.

In formula (5), n is an integer from 1 to 10, preferably from 1 to 4, more preferably from 1 to 3, even more preferably from 1 to 2, and even more preferably 1.

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. When the melting point of the phosphorus-containing compound (B) is 250° C. or higher, it is advantageous in terms of heat resistance, and when it is 360° C. or lower, the Tm-Tc value of the resulting polyimide resin composition can be made lower than that 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.

From the viewpoint of increasing the crystallization rate and improving the heat resistance, it is preferable that in the phosphorus-containing compound (B), R ₅₁ to R ₅₄ are phenyl groups and n is 1 in formula (5).
A specific example of the phosphorus-containing compound (B) is the compound represented by the following structural formula (1,4-bis[(diphenylphosphoroso)methyl]benzene).

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, even more preferably 2 to 15 parts by mass, even more preferably 3 to 15 parts by mass, even more preferably 5 to 15 parts by mass, and even more preferably 8 to 15 parts by mass, per 100 parts by mass of polyimide resin (A). If the content of the phosphorus-containing compound (B) is 0.5 parts by mass or more per 100 parts by mass of polyimide resin (A), it is easy to impart the crystallization rate improving effect and flame retardancy, and if it is 30 parts by mass or less, good appearance and heat resistance can be maintained.

<Additives>
The polyimide resin composition of the present invention may contain additives such as fillers, reinforcing fibers, matting agents, plasticizers, antistatic agents, coloring inhibitors, antigelling agents, colorants, sliding property improvers, antioxidants, conductive agents, and resin modifiers, as necessary.
When the above-mentioned additives are used, there are no particular limitations on the amount of the additives used. From the viewpoint of exerting the effects of the additives while maintaining the physical properties derived from the polyimide resin (A), the amount of the additives used 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.

In addition, the polyimide resin composition of the present invention can be blended with other resins other than the polyimide resin (A) to the extent that the properties are not impaired. As the other resins, highly heat-resistant thermoplastic resins are preferred, and examples thereof include 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 selected from the group consisting of polyetherimide resins, polyphenylene sulfide resins, and polyetheretherketone resins are preferred, from the viewpoints of low water absorption, liquid crystal polymers are preferred, and from the viewpoint of obtaining high flame retardancy, polyphenylene sulfide resins are preferred.
When the polyimide resin (A) is used in combination with other resins, there are no particular limitations on the blending ratio thereof as long as the properties of the polyimide resin composition are not impaired.

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, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less.

The polyimide resin composition of the present invention may take any form, but is preferably in the form of pellets.
Since the polyimide resin composition of the present invention and the polyimide resin (A) used therein have thermoplasticity, for example, the polyimide resin (A), the phosphorus-containing compound (B), and various optional components as required are added and dry-blended, or the phosphorus-containing compound (B) and optional components are separately fed from a location other than the feeding of the polyimide resin (A) to the extruder, and then the resulting mixture is melt-kneaded in the extruder to extrude strands, which are then cut and pelletized. Moreover, the pellets can be introduced into various molding machines and thermoformed by the method described below to easily produce molded articles having desired shapes.
From the viewpoint of forming a pellet, the polyimide resin composition of the present invention preferably does not contain a solvent. Specifically, the content of the solvent 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.

<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 pellets made of the polyimide resin composition can be measured in the same manner as in the polyimide resin (A).

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

[Method of manufacturing molded body]
Since the polyimide resin composition of the present invention has thermoplasticity, 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 molding, compressed air molding, laser molding, welding, adhesion, etc., and molding can be performed by any molding method that involves a thermal melting step.

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), which makes it possible to uniformly disperse the phosphorus-containing compound (B) in the polyimide resin composition, and further makes it easy to lower the Tm-Tc value of the resulting polyimide resin composition as compared to the case of the polyimide resin (A) alone, thereby improving the crystallization rate.
From the above viewpoints, the temperature when the polyimide resin composition is melt-kneaded is preferably a temperature exceeding the melting point of the phosphorus-containing compound (B), more preferably a temperature that is 5°C or higher than the melting point of the phosphorus-containing compound (B), and even more preferably a temperature that is 10°C or higher than the melting point of the phosphorus-containing compound (B).

The temperature at which the polyimide resin composition is melted and kneaded is preferably above the melting point of the polyimide resin (A), and is preferably in the range of 250 to 400°C, more preferably 290 to 360°C, from the viewpoint of melting the polyimide resin (A) and suppressing deterioration of the polyimide resin (A) and the phosphorus-containing compound (B).

As a specific procedure for producing the molded body, for example, the following method can be mentioned.
First, the phosphorus-containing compound (B) and various optional components as required are added to the polyimide resin (A) and dry-blended, and then the mixture is introduced into an extruder, melt-kneaded and extruded in the extruder to prepare pellets. Alternatively, the polyimide resin (A) may be introduced into an extruder to melt, and the phosphorus-containing compound (B) and various optional components as required are introduced thereinto, melt-kneaded with the polyimide resin (A) in the extruder, and extruded to prepare the pellets.
After drying the pellets, they are 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.

<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 conforming to the UL94VTM test (thin material vertical flame test; ASTM D4804), specifically, by the method described in the examples.

<Applications>
The polyimide resin composition and molded article of the present invention can be used for, for example, sixth-generation mobile communication system (6G) related members using 5G or frequency bands of 70 G 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 vehicle-mounted millimeter wave radar, antenna substrates for terahertz wave radar, antenna substrates for aircraft radar, antenna substrates for caterpillar-type 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, multi-layer 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 coats, 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 (vehicle radars, aerospace radars, etc.), radomes (radar domes), optical communication modules (TOSA / ROSA), 8k-TV cable mobile terminals or digital home appliances (tablet terminals, notebook PCs, thin 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 communication equipment, etc.

The polyimide resin composition and molded article of the present invention have a lower melting point than the polyimide resin (A) alone, so when used in a metal foil laminate, it is preferable in that the thermal adhesion to the metal foil is improved. The metal foil laminate will be described below.

[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 a metal foil.
The metal foil laminate mainly includes a copper-clad laminate, which may have a layer of a film-shaped molded product containing the polyimide resin composition (hereinafter, also simply referred to as a "resin film layer") and at least one copper foil layer. For example, a laminate having a configuration in which copper foil is laminated on at least one side, preferably both sides, of a resin film containing the polyimide resin composition can be mentioned.

The resin film used in the manufacture of the copper-clad laminate can be manufactured in the same manner as in the manufacture of the molded body. 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.

The copper foil used in the manufacture of the copper-clad laminate is not particularly limited, and commercially available rolled copper foil, electrolytic copper foil, etc. can be used, but rolled copper foil is preferred from the viewpoint 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 viewpoint of ensuring sufficient electrical conductivity and improving adhesion to the resin film layer. The thickness is the thickness per copper foil layer or per copper foil sheet.
In addition, the surface roughness of the copper foil used in the manufacture of the copper-clad laminate 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 laminating the resin film, and generally, the lower the surface roughness, the better the dielectric properties of the laminate. 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, by a surface roughness meter.

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, from the viewpoint of improving the strength and electrical conductivity of the copper-clad laminate. The copper-clad laminate may have any layer other than the resin film layer and the copper foil layer, as long as the effect of the present invention is not impaired.

The method for producing the copper-clad laminate is not particularly limited, and a known method can be used. For example, the resin film and the copper foil are laminated together under heat and pressure conditions. Since the resin film contains the thermoplastic polyimide resin (A), it is possible to press the surface of the resin film in a heat-melted state and laminate it to the copper foil.
The apparatus used for producing the copper-clad laminate may be any apparatus capable of bonding the resin film and the copper foil under heating and pressurizing conditions, such as a roll laminator, a flat laminator, a vacuum press apparatus, a double belt press apparatus, etc. Among these, from the viewpoint of productivity of the copper-clad laminate and from the viewpoint of obtaining a copper-clad laminate with good appearance, it is preferable to use a vacuum press apparatus or a double belt press apparatus. The double belt press apparatus is an apparatus that has a pair of endless belts arranged above and below, continuously feeds the film-shaped material (resin film and copper foil) that forms each layer between the belts, and heats and presses the material 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.

The heating temperature when manufacturing 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 manufacturing, it is preferably in the range of 250 to 400°C, more preferably 290 to 360°C. Furthermore, the pressure conditions when manufacturing 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 from the viewpoint of reducing the burden on the equipment and manufacturing. Furthermore, from the viewpoint of improving production efficiency, the pressure 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.

The resin film is characterized by its ability to be heat welded, but in the manufacture of copper-clad laminates, it is also possible to use an adhesive to bond the resin film and copper foil together. The adhesive can be any type, such as a varnish-type adhesive, a sheet-type adhesive, or a powder-type adhesive. From the perspective of ensuring low dielectric properties, an adhesive with low dielectric properties is also preferred. An example of an adhesive with low dielectric properties is the polyimide adhesive "PIAD" series manufactured by Arakawa Chemical Industries Co., Ltd.

（Ｒ_５１～Ｒ_５４はそれぞれ独立に、炭素数１～１２の炭化水素基である。Ｙは－Ｒ_５５－Ｚ－Ｒ_５６－で示される２価の基である。Ｒ_５５及びＲ_５６はそれぞれ独立に、単結合又は炭素数１～１２のアルキレン基であり、Ｚはアリーレン基である。ｎは１～１０の整数である。）
　結晶性熱可塑性樹脂に前記リン含有化合物（Ｂ）を配合することで、該結晶性熱可塑性樹脂の結晶化速度を向上させることができる。 [use]
The present invention can also provide use of a phosphorus-containing compound (B) represented by the following formula (5) as an agent for improving the crystallization rate of a crystalline thermoplastic resin.

(R ₅₁ to R ₅₄ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is a divalent group represented by -R ₅₅ -Z-R ₅₆ -. 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 from 1 to 10.)
By blending the phosphorus-containing compound (B) with the crystalline thermoplastic resin, the crystallization rate of the crystalline thermoplastic resin can be improved.

The amount of phosphorus-containing compound (B) to be blended with respect to 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, even more preferably 2 to 15 parts by mass, even more preferably 3 to 15 parts by mass, even more preferably 5 to 15 parts by mass, and even more preferably 8 to 15 parts by mass, per 100 parts by mass of the crystalline thermoplastic resin.

（Ｒ_１は少なくとも１つの脂環式炭化水素構造を含む炭素数６～２２の２価の基である。Ｒ_２は炭素数５～１６の２価の鎖状脂肪族基である。Ｘ_１及びＸ_２は、それぞれ独立に、少なくとも１つの芳香環を含む炭素数６～２２の４価の基である。）
　ポリイミド樹脂（Ａ）、リン含有化合物（Ｂ）、並びにこれらの好適態様については、前記と同じである。 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 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 %.

( _R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. _R2 is a divalent chain aliphatic group having 5 to 16 carbon atoms. _X1 and _X2 are each independently a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.)
The polyimide resin (A), the phosphorus-containing compound (B), and the preferred embodiments thereof are the same as those described above.

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 manufacturing example and example were carried out as follows.

<Infrared Spectroscopic Analysis (IR Measurement)>
The IR measurement of the polyimide resin was carried out using a JIR-WINSPEC50 manufactured by JEOL Ltd.

<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 ("DSC-25" manufactured by TA Instruments). In each measurement, resin powder was used as the measurement sample for the polyimide resin (Comparative Examples 1 and 2), and pellets were used as the measurement sample for the other polyimide resin compositions.
Under a nitrogen atmosphere (nitrogen gas flow rate 50 ml/min), the measurement sample was subjected to the following thermal history conditions: first heating (heating rate 10° C./min), then cooling (cooling rate 20° C./min), then second heating (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 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) observed near the melting point when the measurement sample was heated to a temperature above the melting point at a heating rate of 10° C./min to melt, 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 heat of crystallization peak observed when the measurement sample was heated to a temperature above the melting point at a heating rate of 10° C./min to melt, and then cooled at a heating rate of 20° C./min.

<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 Co., Ltd. In each measurement, a resin powder was used as a measurement sample for the polyimide resin (Comparative Examples 1 and 2), and a pellet was used as a measurement sample 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: 1.0mL/min
Sample concentration: about 0.1% by mass
Detector: IR detector Injection amount: 100 μm
Calibration curve: Standard PMMA

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

(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 of methane gas twice for 3 seconds. The total flaming time (seconds) when the film was exposed to a 20 mm high flame of methane gas twice is shown in Table 2 (n=5). A shorter total time indicates better flame retardancy.

(Whether or not combustion reaches the 125 mm mark)
The presence or absence of flame reaching the 125 mm mark from the bottom end of the film was observed, 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.

(Whether or not cotton ignites)
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 ignited during the five tests is shown in Table 2. When there was no ignition, it was recorded as "none". The fewer the number of ignitions, the higher the drip prevention effect and the better the flame retardancy.

(Determination of flame retardancy)
Flame retardancy was ranked based on the UL94VTM criteria. In Table 2, if the material has flame retardancy equivalent to VTM-0, it is listed as "VTM-0 equivalent," if it has flame retardancy equivalent to VTM-1, it is listed as "VTM-1 equivalent," and if it has flame retardancy equivalent to VTM-2, it is listed as "VTM-2 equivalent." Flame retardancy increases in the order of VTM-0>1>2, and if it does not reach flame retardancy equivalent to VTM-2, it is listed as "not VTM compliant."

Production Example 1 (Production of Polyimide Resin 1)
In a 2L separable flask equipped with a Dean-Stark apparatus, a Liebig condenser, a thermocouple, and four paddle blades, 600g of 2-(2-methoxyethoxy)ethanol (manufactured by Nippon Nyukazai Co., Ltd.) and 218.58g (1.00mol) of pyromellitic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were introduced, and after nitrogen flow, the mixture was stirred at 150 rpm to obtain a uniform suspension solution. Meanwhile, using a 500mL beaker, 49.42g (0.347mol) of 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., cis/trans ratio = 7/3) and 93.16g (0.645mol) of 1,8-octamethylenediamine (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 250g 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 the drop generates heat, the internal temperature was adjusted to be within 40 to 80°C. The mixed diamine solution was dropped under nitrogen flow conditions, and the stirring blade rotation speed was 250 rpm. After the drop was completed, 130 g of 2-(2-methoxyethoxy)ethanol and 1.934 g (0.00149 mol) of n-octylamine (manufactured by Kanto Chemical Co., Ltd.), which is 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 2L separable flask was heated to 190°C. During the temperature increase, precipitation of polyimide resin powder and dehydration due to imidization were confirmed when the liquid temperature was between 120 and 140°C. After holding at 190°C for 30 minutes, the solution was allowed to cool to room temperature and filtered. The resulting 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 polyimide resin 1 powder.
The IR spectrum of the polyimide resin 1 showed characteristic absorption of imide ring at 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.

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, and the mixture was stirred at 150 rpm to obtain a uniform suspension solution after nitrogen flow. 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 the drop generates heat, the internal temperature was adjusted to be within 40 to 80°C. The mixed diamine solution was dropped under nitrogen flow conditions, and the stirring blade rotation speed was 250 rpm. After the drop was completed, 10 g of 2-(2-methoxyethoxy)ethanol and 1.541 g (0.012 mol) of n-octylamine (manufactured by Kanto Chemical Co., Ltd.), which is 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 2L separable flask was heated to 185°C. During the temperature increase, precipitation of polyimide resin powder and dehydration due to imidization were confirmed when the liquid temperature was between 120 and 140°C. After holding at 185°C for 120 minutes, the solution was allowed to cool to room temperature and 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 crystalline thermoplastic polyimide resin 2 (hereinafter also simply referred to as “polyimide resin 2”) powder.
The IR spectrum of the polyimide resin 2 showed characteristic absorption of the imide ring at ν(C═O) 1768 and 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.

The composition of the polyimide resin in the manufacturing example is shown in Table 1. The mole percentages of the tetracarboxylic acid component and diamine component in Table 1 are values calculated from the amount of each component charged when the polyimide resin is manufactured.

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

Examples 1 to 6 (Production and Evaluation of Polyimide Resin Compositions and Molded Articles (Resin Films))
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 obtained 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) under conditions of a barrel temperature of 350°C and a screw rotation speed of 200 rpm for Examples 2 to 4, and using a small twin-screw extruder under conditions of a barrel temperature of 360°C and a screw rotation speed of 100 rpm for Examples 1, 5, and 6.
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.).
In Examples 2 to 4, the obtained pellets (polyimide resin composition) were dried at 190° C. for 10 hours and then used for extrusion molding in the following manner.
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. Thereafter, the pellets were cooled with a metal roll, which was a cooling roll at 140° C., to obtain a resin film having a thickness of 0.05±0.01 mm.
Here, 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 obtained pellets (polyimide resin composition) or the prepared resin film were subjected to various evaluations by the above-mentioned methods. The results are shown in Table 2.

Comparative Example 1
The powder of polyimide resin 1 obtained in Production Example 1 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) under conditions of a barrel temperature of 350°C and a screw rotation speed of 120 rpm.
The strand extruded from the extruder was air-cooled and then pelletized with a pelletizer ("Fan Cutter FC-Mini-4/N" manufactured by Hoshi Plastics Co., Ltd.) The obtained 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. Thereafter, the pellets were cooled with a metal roll, which was a cooling roll at 140° C., to obtain a resin film having a thickness of 0.05±0.01 mm.
Here, 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 powder of polyimide resin 1 obtained in Production Example 1 or the prepared resin film was used to carry out various evaluations by the methods described above. The results are shown in Table 2.

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.

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

Comparison of Comparative Example 1 with Examples 1 to 5 and Comparison Example 2 with Example 6 in Table 2 reveals that the polyimide resin compositions of the present invention have a lower Tm-Tc value, i.e., a higher crystallization rate, than the polyimide resin alone. Furthermore, the polyimide resin compositions of Examples 1 to 6 suppress the decrease in molecular weight even when thermally melted, compared to the polyimide resin alone.
In addition, by comparing Comparative Example 1 with Examples 2 to 4, it can be seen that the molded articles of Examples 2 to 4 containing the polyimide resin composition of the present invention also have improved flame retardancy as compared to the molded article of Comparative Example 1.

The present invention provides a polyimide resin composition that contains a crystalline thermoplastic polyimide resin of a specific structure and has a crystallization rate that is faster than that of the resin alone, a molded article that contains the polyimide resin composition, a method for producing the molded article, and a metal foil laminate.

Claims (8)

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).

( _R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. _R2 is a divalent chain aliphatic group having 5 to 16 carbon atoms. _X1 and _X2 are each independently a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.)

(R ₅₁ to R ₅₄ are each independently a hydrocarbon group having 1 to 12 carbon atoms. Y is a divalent group represented by -R ₅₅ -Z-R ₅₆ -. 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 from 1 to 10.) 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). 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. The polyimide resin composition according to claim 1, wherein in the formula (5), R ₅₁ to R ₅₄ are a phenyl group, and n is 1. The polyimide resin composition according to any one of claims 1 to 4, in which Tm-Tc is 50°C or less, where Tm (°C) is the melting point of the pellet made of the polyimide resin composition, and Tc (°C) is the crystallization temperature. A molded article comprising the polyimide resin composition according to any one of claims 1 to 5. A method for producing a molded product, comprising a 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). A metal foil laminate having a layer made of the molded body according to claim 6 and a layer made of metal foil.