Polyimide resin composition and molded article

Abstract

A polyimide resin composition and a molded article containing the same, the polyimide resin composition comprising a polyimide resin (A) and a polyethersulfone resin (B), the polyimide resin (A) comprising a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), and the content ratio of the repeating structural unit of the formula (1) is 20 to 70 mol% based on the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2), and the mass ratio [(A) / (B)] of the component (A) to the component (B) is 0.1 / 99.9 to 65 / 35. (R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. R2 is a divalent linear 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.)

Description

Technical Field

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

[0002] Polyimide resins are useful engineering plastics having high heat stability, high strength, and high solvent resistance due to the rigidity of the molecular chain, resonance stabilization, and strong chemical bonds, and are used in a wide range of fields. In addition, crystalline polyimide resins can further improve their heat resistance, strength, and chemical resistance, and thus are expected to be used as a substitute for metals. However, while polyimide resins have high heat resistance, they have the problem of not exhibiting thermoplasticity and having low moldability.

[0003] High heat-resistant resins such as VESPEL (registered trademark) are known as polyimide molding materials (Patent Document 1), but even at high temperatures, their fluidity is extremely low, so molding is difficult and requires long-term molding under high temperature and high pressure conditions, which is also disadvantageous in terms of cost. On the other hand, if it is a resin having a melting point and fluidity at high temperatures like a crystalline resin, it can be easily and inexpensively molded.

[0004] Therefore, in recent years, polyimide resins having thermoplasticity have been reported. Thermoplastic polyimide resins are excellent in moldability in addition to the heat resistance inherent in polyimide resins. Therefore, thermoplastic polyimide resins can also be applied to molded articles used in harsh environments where general thermoplastic resins such as nylon and polyester cannot be applied.

[0005] For example, Patent Document 2 discloses a thermoplastic polyimide resin containing a specified repeating structural unit, which is obtained by reacting a tetracarboxylic acid and / or its derivative containing at least one aromatic ring, a diamine containing at least one alicyclic hydrocarbon structure, and a linear aliphatic diamine.

[0006] In the field of engineering plastics, a technique of compounding two or more thermoplastic resins to form an alloy for the purpose of improving physical properties and imparting functions corresponding to uses is known. Patent Document 3 discloses a thermoplastic polyimide resin containing a specified repeating unit, and also describes a case where the polyimide resin is used in combination with other resins as a polymer alloy. Patent Document 4 discloses a polyimide-based resin composition having excellent heat resistance, rigidity, and impact resistance, which contains a polyetherimide resin and a crystalline polyimide resin, and the crystalline polyimide resin contains a tetracarboxylic acid component and an aliphatic diamine component.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-28524

[0010] Patent Document 2: WO 2013 / 118704

[0011] Patent Document 3: WO 2016 / 147996

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2018-70699 Summary of the Invention

[0013] Problem that the invention aims to solve

[0014] The thermoplastic polyimide resin described in Patent Document 3 has crystallinity and is excellent in heat resistance, strength, chemical resistance, etc., but there is still room for further improvement in the tensile properties, particularly toughness, among the mechanical properties. It is considered that when the toughness is improved, the impact resistance, vibration damping property, etc. are also improved, and expansion to applications that value these properties is expected. The improvement of the toughness described here means that the elongation until fracture increases when a tensile stress is applied to the molded body, and can be evaluated, for example, by measuring the tensile fracture strain.

[0015] In the examples of Patent Document 4, the tensile modulus and the elongation at break of the molded body formed from the polyimide resin composition containing the polyetherimide resin and the crystalline polyimide resin were evaluated, but in any of the examples, the elongation at break exceeding that of the crystalline polyimide resin alone was not obtained.

[0016] An object of the present invention is to provide a polyimide resin composition and a molded body in which the heat resistance, bending properties, etc. derived from the crystalline thermoplastic polyimide resin are maintained at a high level while the toughness is further improved.

[0017] Solutions for solving problems

[0018] The present inventors have found that the following polyimide resin composition can solve the above problems. The polyimide resin composition contains, at a specified mass ratio: a crystalline thermoplastic polyimide resin obtained by combining specific different polyimide structural units at a specific ratio, and a polyethersulfone resin.

[0019] That is, the present invention relates to the following.

[0020] [1] A polyimide resin composition comprising a polyimide resin (A) and a polyethersulfone resin (B), wherein the polyimide resin (A) comprises a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), and the content ratio of the repeating structural unit of formula (1) is 20 to 70 mol% based on the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2), and the mass ratio [(A) / (B)] of component (A) to component (B) is 0.1 / 99.9 to 65 / 35.

[0021]

[0022] (R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. R2 is a divalent linear 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.)

[0023] [2] A molded article comprising the polyimide resin composition described in [1] above.

[0024] Effects of the Invention

[0025] Regarding the polyimide resin composition and the molded article of the present invention, they have excellent heat resistance and bending properties and high toughness, and thus are expected to be applied to uses that value impact resistance, vibration damping properties, etc. For example, they can be applied to sliding members such as gears and bearings, cutting members, structural members such as robotic arms, winding coating materials such as electric wires, screws, nuts, seals, speaker diaphragms, reflectors, components related to the fifth-generation mobile communication system (5G) and the sixth-generation mobile communication system (6G), various films, etc. In addition, it can also be expected to be applied to uses such as water treatment membranes for the same uses as polyethersulfone resins.

[0026] Explanation of reference numerals

[0027] Figure 1 It is a schematic diagram showing a method for manufacturing a sample (ultrathin section) for field emission scanning transmission electron microscope (FE-STEM) observation.

[0028] Figure 2 It is a micrograph when observing a cross-section cut parallel to the flow direction (MD) of the polyimide resin composition (granules) of Example 1 using FE-STEM.

[0029] Figure 3 It is a micrograph when observing a cross-section cut parallel to the MD of the polyimide resin composition (granules) of Example 2 using FE-STEM.

[0030] Figure 4Microscopic images of the cross-section of the polyimide resin composition (granules) of Comparative Example 1 cut parallel to the MD, as observed using FE-STEM.

[0031] Figure 5 Microscopic images of the cross-section of the granules of the polyethersulfone resin (B1) of Reference Example 1 cut parallel to the MD, as observed using FE-STEM. Detailed Description

[0032] [Polyimide Resin Composition]

[0033] The polyimide resin composition of the present invention contains a polyimide resin (A) and a polyethersulfone resin (B). The aforementioned polyimide resin (A) contains a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2). The content ratio of the repeating structural unit of formula (1) is 20 to 70 mol% with respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2). The mass ratio [(A) / (B)] of component (A) to component (B) is 0.1 / 99.9 to 65 / 35.

[0034]

[0035] (R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. R2 is a divalent linear 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.)

[0036] By having the aforementioned constitution, the polyimide resin composition of the present invention can maintain heat resistance, bending properties, etc. at a high level, and can also improve toughness compared to the case of component (A) alone or component (B) alone.

[0037] The reason for this is not yet certain, but it is thought that since component (A) is a crystalline thermoplastic resin, component (B) is an amorphous thermoplastic resin, and they have a high mutual dispersibility, a resin composition and a molded article in which component (A) is microdispersed from the micron scale to the nanometer scale are formed. It is speculated that in the molded article in which component (A) is microdispersed at the micron to nanometer scale, stress is dispersed when stress is applied. Therefore, for example, when tensile stress is applied, internal cracks in the molded article are generated complexly, and strain is relieved at multiple points, thus improving toughness.

[0038] [Polyimide Resin (A)]

[0039] The polyimide resin (A) used in the present invention contains a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2). With respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2), the content ratio of the repeating structural unit of formula (1) is 20 to 70 mol%.

[0040]

[0041] (R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure. R2 is a divalent linear 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.)

[0042] The polyimide resin (A) used in the present invention is a crystalline thermoplastic resin, and its form is preferably powder or pellets. For thermoplastic polyimide resins, they are distinguished from, for example, polyimide resins that do not have a glass transition temperature (Tg) formed by closing the imide ring after molding in the state of polyimide precursors such as polyamic acid, or polyimide resins that decompose at a temperature below the glass transition temperature.

[0043] The repeating structural unit of formula (1) will be described in detail below.

[0044] R1 is a divalent group having 6 to 22 carbon atoms 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 can be saturated or unsaturated, and can be monocyclic or polycyclic.

[0045] Examples of the alicyclic hydrocarbon structure include cycloalkane rings such as cyclohexane rings, cycloalkene rings such as cyclohexene rings, bicycloalkane rings such as norbornane rings, and bicycloalkene rings such as norbornene rings, but are not limited thereto. Among them, cycloalkane rings are preferred, cycloalkane rings having 4 to 7 carbon atoms are more preferred, and cyclohexane rings are further preferred.

[0046] The number of carbon atoms of R1 is 6 to 22, preferably 8 to 17.

[0047] R1 contains at least one alicyclic hydrocarbon structure, preferably 1 to 3.

[0048] R1 is preferably a divalent group represented by the following formula (R1-1) or (R1-2).

[0049]

[0050] (m 11 and m 12 are each independently an integer from 0 to 2, preferably 0 or 1. m 13 to m15 Each independently represents an integer from 0 to 2, preferably 0 or 1.)

[0051] R1 is particularly preferably a divalent group represented by the following formula (R1-3).

[0052]

[0053] 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 cis or trans, and the ratio of cis to trans may be any value.

[0054] X1 is a tetravalent group having 6 to 22 carbon atoms and including at least one aromatic ring. The aromatic ring may be a monocyclic 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 them, a benzene ring and a naphthalene ring are preferred, and a benzene ring is more preferred.

[0055] The number of carbon atoms in X1 is 6-22, preferably 6-18.

[0056] X1 contains at least one aromatic ring, preferably 1 to 3 aromatic rings.

[0057] X1 is preferably a tetravalent group represented by any of the following formulae (X-1) to (X-4).

[0058]

[0059] (R 11 ~R 18 Each is independently an alkyl group having 1 to 4 carbon atoms. 11 ~p 13 Each independently represents an integer of 0 to 2, preferably 0. 14 、p 15 、p 16 and p 18 Each independently represents an integer of 0 to 3, preferably 0. 17 is an integer of 0 to 4, preferably 0. 11 ~L 13 Each is independently a single bond, a carbonyl group, or an alkylene group having 1 to 4 carbon atoms.)

[0060] It should be noted that X1 is a tetravalent group having 6 to 22 carbon atoms and containing at least one aromatic ring, so R in formula (X-2) 12 , R 13 、p 12 and p 13 The tetravalent group represented by the formula (X-2) is selected so that the number of carbon atoms is within the range of 10 to 22.

[0061] Similarly, L in formula (X-3) 11 , R 14 , R 15 , p 14 and p 15 are selected in such a way 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 are selected in such a way that the number of carbon atoms of the tetravalent group represented by formula (X-4) is in the range of 18 to 22.

[0062] X1 is particularly preferably a tetravalent group represented by the following formula (X-5) or (X-6).

[0063]

[0064] Next, the repeating structural unit of formula (2) will be described in detail.

[0065] R2 is a divalent linear aliphatic group having 5 to 16 carbon atoms, preferably 6 to 14 carbon atoms, more preferably 7 to 12 carbon atoms, and further preferably 8 to 10 carbon atoms. Here, the linear aliphatic group means a group derived from a linear aliphatic compound, and the linear aliphatic compound may be saturated or unsaturated, and may be linear or branched.

[0066] R2 is preferably an alkylene group having 5 to 16 carbon atoms, more preferably 6 to 14 carbon atoms, still more preferably 7 to 12 carbon atoms, and among them, an alkylene group having 8 to 10 carbon atoms is preferred. The aforementioned alkylene group may be a linear alkylene group or a branched alkylene group, and a linear alkylene group is preferred.

[0067] R2 is preferably at least one selected from the group consisting of octamethylene and decamethylene, and particularly preferably octamethylene.

[0068] X2 is defined in the same manner as X1 in formula (1), and the preferred modes are also the same.

[0069] With respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2), the content ratio of the repeating structural unit of formula (1) is 20 to 70 mol%. When the content ratio of the repeating structural unit of formula (1) is within the aforementioned range, the polyimide resin can be sufficiently crystallized even in a normal injection molding cycle. When this content ratio is less than 20 mol%, the moldability is reduced, and when it exceeds 70 mol%, the crystallinity is reduced, and thus the heat resistance is reduced.

[0070] From the viewpoint of exhibiting high crystallinity, the content ratio of the repeating structural unit of the formula (1) is preferably 65 mol% or less, more preferably 60 mol% or less, still more preferably 50 mol% or less, and even more preferably less than 40 mol% with respect to the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2).

[0071] When the content ratio of the repeating structural unit of the formula (1) is 20 mol% or more and less than 40 mol% with respect to the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2), the crystallinity of the polyimide resin (A) becomes high, and a resin molded body having more excellent heat resistance can be obtained. From the viewpoint of moldability, the above content ratio is preferably 25 mol% or more, more preferably 30 mol% or more, still more preferably 32 mol% or more, and from the viewpoint of exhibiting high crystallinity, even more preferably 35 mol% or less.

[0072] The content ratio of the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2) is preferably 50 to 100 mol%, more preferably 75 to 100 mol%, still more preferably 80 to 100 mol%, and even more preferably 85 to 100 mol% with respect to all the repeating structural units constituting the polyimide resin (A).

[0073] 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 the formula (3) is preferably 25 mol% or less with respect to the total of the repeating structural unit of the formula (1) and the repeating structural unit of the formula (2). On the other hand, the lower limit is not particularly limited as long as it exceeds 0 mol%.

[0074] In the case of containing the repeating structural unit of the formula (3), from the viewpoint of improving heat resistance, the above content ratio is preferably 5 mol% or more, more preferably 10 mol% or more, and on the other hand, from the viewpoint of maintaining crystallinity, it is preferably 20 mol% or less, more preferably 15 mol% or less.

[0075]

[0076] (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.)

[0077] R3 is a divalent group having 6 to 22 carbon atoms containing at least one aromatic ring. The aforementioned aromatic ring may be a monocyclic 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 thereto. Among them, a benzene ring and a naphthalene ring are preferred, and a benzene ring is more preferred.

[0078] The number of carbon atoms in R3 is 6 to 22, preferably 6 to 18.

[0079] R3 contains at least one aromatic ring, preferably 1 to 3 aromatic rings.

[0080] R3 is preferably a divalent group represented by the following formula (R3-1) or (R3-2).

[0081]

[0082] (m 31 and m 32 are each independently an integer from 0 to 2, preferably 0 or 1. m 33 and m 34 are each independently an integer from 0 to 2, preferably 0 or 1. R 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. p 21 、p 22 and p 23 are integers from 0 to 4, preferably 0. L 21 is a single bond, a carbonyl group, or an alkylene group having 1 to 4 carbon atoms.)

[0083] It should be noted that R3 is a divalent group having 6 to 22 carbon atoms and containing at least one aromatic ring. Therefore, m 31 、m 32 、R 21 and p 21 are selected in such a way that the number of carbon atoms in the divalent group represented by formula (R3-1) is in the range of 6 to 22.

[0084] Similarly, L 21 、m 33 、m 34 、R 22 、R 23 、p 22 and p 23 in formula (R3-2) are selected in such a way that the number of carbon atoms in the divalent group represented by formula (R3-2) is in the range of 12 to 22.

[0085] X3 is defined in the same way as X1 in formula (1), and the preferred forms are also the same.

[0086] There is no particular limitation on the terminal structure of the polyimide resin (A), and it preferably has a linear aliphatic group having 5 to 14 carbon atoms at the terminal.

[0087] The chain aliphatic group may be saturated or unsaturated, and may be linear or branched. If the polyimide resin (A) has the above-mentioned specific group at the terminal, a resin composition excellent in heat aging resistance can be obtained.

[0088] Examples of the saturated chain aliphatic group having 5 to 14 carbon atoms include n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, dodecyl, n-tridecyl, n-tetradecyl, isopentyl, neopentyl, 2-methylpentyl, 2-methylhexyl, 2-ethylpentyl, 3-ethylpentyl, isooctyl, 2-ethylhexyl, 3-ethylhexyl, isononyl, 2-ethyloctyl, isodecyl, isododecyl, isotridecyl, isotetradecyl, etc.

[0089] Examples of the unsaturated chain aliphatic group 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, tetradecenyl, etc.

[0090] Among them, the above-mentioned chain aliphatic group is preferably a saturated chain aliphatic group, more preferably a saturated linear chain aliphatic group. In addition, from the viewpoint of obtaining heat aging resistance, the above-mentioned chain aliphatic group preferably has 6 or more carbon atoms, more preferably 7 or more carbon atoms, further preferably 8 or more carbon atoms, preferably 12 or less carbon atoms, more preferably 10 or less carbon atoms, and further preferably 9 or less carbon atoms. The above-mentioned chain aliphatic group may be only 1 kind, or may be 2 or more kinds.

[0091] The above-mentioned chain aliphatic group is particularly preferably at least one selected from the group consisting of n-octyl, isooctyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl and isodecyl, more preferably at least one selected from the group consisting of n-octyl, isooctyl, 2-ethylhexyl, n-nonyl and isononyl, and most preferably at least one selected from the group consisting of n-octyl, isooctyl and 2-ethylhexyl.

[0092] In addition, from the viewpoint of heat aging resistance, the polyimide resin (A) preferably has only a chain aliphatic group having 5 to 14 carbon atoms at the terminal except for the terminal amino group and the terminal carboxyl group. When there are other groups at the terminal, its content is preferably 10 mol% or less, more preferably 5 mol% or less, relative to the chain aliphatic group having 5 to 14 carbon atoms.

[0093] From the viewpoint of excellent heat aging resistance, the content of the linear aliphatic group having 5 to 14 carbon atoms in the polyimide resin (A) is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, and further preferably 0.2 mol% or more, based on 100 mol% in total of all the repeating structural units constituting the polyimide resin (A). In addition, in order to ensure a sufficient molecular weight and obtain good mechanical properties, the content of the linear aliphatic group having 5 to 14 carbon atoms in the polyimide resin (A) is preferably 10 mol% or less, more preferably 6 mol% or less, further preferably 3.5 mol% or less, still more preferably 2.0 mol% or less, and still more preferably 1.2 mol% or less, based on 100 mol% in total of all the repeating structural units constituting the polyimide resin (A).

[0094] The content of the linear aliphatic group having 5 to 14 carbon atoms in the polyimide resin (A) can be determined by depolymerizing the polyimide resin (A).

[0095] The polyimide resin (A) preferably has a melting point of 360°C or lower and a glass transition temperature of 150°C or higher. From the viewpoint of heat resistance, the melting point of the polyimide resin (A) is more preferably 280°C or higher, and further preferably 290°C or higher. From the viewpoint of exhibiting high moldability, it is preferably 345°C or lower, more preferably 340°C or lower, and further preferably 335°C or lower. In addition, from the viewpoint of heat resistance, the glass transition temperature of the polyimide resin (A) is more preferably 160°C or higher, and still more preferably 170°C or higher. From the viewpoint of exhibiting high moldability, it is preferably 250°C or lower, more preferably 230°C or lower, and further preferably 200°C or lower.

[0096] In addition, from the viewpoints of improving crystallinity, heat resistance, mechanical strength, and chemical resistance, when the polyimide resin (A) is measured by a differential scanning calorimeter and the polyimide resin is melted and then cooled at a cooling rate of 20°C / minute, the heat of the crystallization exothermic peak observed (hereinafter, simply referred to as "heat of crystallization") is preferably 5.0 mJ / mg or more, more preferably 10.0 mJ / mg or more, and further preferably 17.0 mJ / mg or more. The upper limit value of the heat of crystallization is not particularly limited and is usually 45.0 mJ / mg or less.

[0097] The melting point, glass transition temperature, and heat of crystallization of the polyimide resin (A) can all be measured by a differential scanning calorimeter, and specifically, they can be measured by the method described in the examples.

[0098] The weight-average molecular weight Mw of the polyimide resin (A) preferably ranges from 10,000 to 150,000, more preferably from 15,000 to 100,000, still more preferably from 20,000 to 80,000, even more preferably from 30,000 to 70,000, and even more preferably from 35,000 to 65,000. If the weight-average molecular weight Mw of the polyimide resin (A) is 10,000 or more, the mechanical strength of the resulting molded article becomes good, and if it is 40,000 or more, the stability of the mechanical strength becomes good. In addition, if it is 150,000 or less, the moldability becomes good.

[0099] 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. Specifically, it can be measured by the method described in the examples.

[0100] The range of the logarithmic viscosity of a 5% by mass sulfuric acid solution of the polyimide resin (A) at 30 °C is preferably from 0.8 to 2.0 dL / g, more preferably from 0.9 to 1.8 dL / g. If the logarithmic viscosity is 0.8 dL / g or more, sufficient mechanical strength can be obtained when forming the molded article. When the logarithmic viscosity is 2.0 dL / g or less, the moldability and operability become good. The logarithmic viscosity μ is measured by using a Cannon-Fenske viscometer to measure the flow times of concentrated sulfuric acid and the above polyimide resin solution at 30 °C, and is calculated by the following formula.

[0101] μ = ln[(ts / t0) / C]

[0102] t0: Flow time of concentrated sulfuric acid

[0103] ts: Flow time of polyimide resin solution

[0104] C: 0.5 (g / dL)

[0105] (Method for producing polyimide resin (A))

[0106] 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 containing at least one aromatic ring and / or its derivative, and the diamine component contains a diamine containing at least one alicyclic hydrocarbon structure and a linear aliphatic diamine.

[0107] The tetracarboxylic acid containing at least one aromatic ring is preferably a compound obtained by directly bonding four carboxyl groups to the aromatic ring, and the structure may contain an alkyl group. Additionally, the aforementioned tetracarboxylic acid preferably has 6 to 26 carbon atoms. As the aforementioned tetracarboxylic acid, pyromellitic acid, 2,3,5,6-toluene tetracarboxylic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 3,3',4,4'-biphenyl tetracarboxylic acid, 1,4,5,8-naphthalene tetracarboxylic acid, etc. are preferred. Among these, pyromellitic acid is more preferred.

[0108] As derivatives of the tetracarboxylic acid containing at least one aromatic ring, acid anhydrides or alkyl esters of the tetracarboxylic acid containing at least one aromatic ring can be cited. The aforementioned tetracarboxylic acid derivative preferably has 6 to 38 carbon atoms. As acid anhydrides of the tetracarboxylic acid, pyromellitic acid monoanhydride, pyromellitic dianhydride, 2,3,5,6-toluene tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, etc. can be cited. As alkyl esters of the tetracarboxylic acid, dimethyl pyromellitate, diethyl pyromellitate, dipropyl pyromellitate, diisopropyl pyromellitate, dimethyl 2,3,5,6-toluene tetracarboxylate, dimethyl 3,3',4,4'-diphenylsulfone tetracarboxylate, dimethyl 3,3',4,4'-benzophenone tetracarboxylate, dimethyl 3,3',4,4'-biphenyl tetracarboxylate, dimethyl 1,4,5,8-naphthalene tetracarboxylate, etc. can be cited. Among the above alkyl esters of the tetracarboxylic acid, the alkyl group preferably has 1 to 3 carbon atoms.

[0109] The tetracarboxylic acid containing at least one aromatic ring and / or its derivatives can be used alone, selecting at least one compound from the above, or two or more compounds can be used in combination.

[0110] The carbon atoms of the diamine containing at least one alicyclic hydrocarbon structure preferably have 6 to 22. For example, 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), carboxydiamine, limonene diamine, isophorone diamine, norbornene diamine, bis(aminomethyl)tricyclo[5.2.1.0 2,6 decane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylpropane, etc. These compounds can be used alone, or two or more compounds selected from them can be used in combination. Among them, 1,3-bis(aminomethyl)cyclohexane can be suitably used. It should be noted that diamines containing an alicyclic hydrocarbon structure generally have structural isomers, but the ratio of cis / trans isomers is not limited.

[0111] The chain aliphatic diamine can be straight-chain or branched-chain, and preferably has 5 to 16 carbon atoms, more preferably 6 to 14 carbon atoms, and further preferably 7 to 12 carbon atoms. In addition, the number of carbon atoms in the chain part only needs to be 5 to 16, and an ether bond can be included 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(ethylamine), etc. are preferred.

[0112] One or more chain aliphatic diamines can be used in combination. Among these, chain aliphatic diamines having 8 to 10 carbon atoms can be suitably used, and at least one selected from the group consisting of 1,8-octamethylenediamine and 1,10-decamethylenediamine can be particularly suitably used.

[0113] When producing the polyimide resin (A), the molar ratio of the input 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 20 to 70 mol%. This molar amount is preferably 25 mol% or more, more preferably 30 mol% or more, further preferably 32 mol% or more, and from the viewpoint of exhibiting high crystallinity, it is preferably 60 mol% or less, more preferably 50 mol% or less, further preferably less than 40 mol%, and further preferably 35 mol% or less.

[0114] In addition, in the above diamine component, a diamine containing at least one aromatic ring can be contained. The diamine containing at least one aromatic ring preferably has 6 to 22 carbon atoms, and examples thereof include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 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, 1,5-diaminonaphthalene, etc.

[0115] Among the above, the molar ratio of the input amount of diamine containing at least one aromatic ring to the total amount of diamine containing at least one alicyclic hydrocarbon structure and linear aliphatic diamine is preferably 25 mol% or less, more preferably 20 mol% or less, and still more preferably 15 mol% or less.

[0116] The lower limit of the aforementioned molar ratio is not particularly limited, but from the viewpoint of improving heat resistance, it is preferably 5 mol% or more, more preferably 10 mol% or more.

[0117] On the other hand, from the viewpoint of reducing the coloring of the polyimide resin, the aforementioned molar ratio is further preferably 12 mol% or less, still more preferably 10 mol% or less, still more preferably 5 mol% or less, and still more preferably 0 mol%.

[0118] When manufacturing the polyimide resin (A), for the input amount ratio of the aforementioned tetracarboxylic acid component to the aforementioned diamine component, relative to 1 mol of the tetracarboxylic acid component, the diamine component is preferably 0.9 to 1.1 mol.

[0119] In addition, when manufacturing the polyimide resin (A), in addition to the aforementioned tetracarboxylic acid component and the aforementioned diamine component, a capping agent can also be mixed. As the capping agent, at least one selected from the group consisting of monoamines and dicarboxylic acids is preferably used. The amount of the capping agent is sufficient as long as it can introduce a desired amount of end groups into the polyimide resin (A). Relative to 1 mol of the aforementioned tetracarboxylic acid and / or its derivative, it is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.06 mol, still more preferably 0.002 to 0.035 mol, still more preferably 0.002 to 0.020 mol, and still more preferably 0.002 to 0.012 mol.

[0120] Among them, a monoamine capping agent is preferably used as the capping agent. From the viewpoint of introducing the aforementioned linear aliphatic group having 5 to 14 carbon atoms into the end of the polyimide resin (A) to improve heat aging resistance, a monoamine having a linear aliphatic group having 5 to 14 carbon atoms is more preferably used, and a monoamine having a saturated straight-chain aliphatic group having 5 to 14 carbon atoms is still more preferably used.

[0121] The 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, still 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.

[0122] As the polymerization method for manufacturing the polyimide resin (A), a known polymerization method can be applied, and the method described in International Publication No. 2016 / 147996 can be used.

[0123] <Polyethersulfone resin (B)>

[0124] The polyimide resin composition of the present invention contains the aforementioned polyimide resin (A) and polyethersulfone resin (B) in a mass ratio [(A) / (B)] of 0.1 / 99.9 to 65 / 35. By containing the polyimide resin (A) and polyethersulfone resin (B) at a specified ratio, a polyimide resin composition and a molded article can be obtained that maintain heat resistance, bending properties, etc. at a high level and have further improved toughness.

[0125] The polyethersulfone resin used as component (B) is an amorphous thermoplastic resin containing a repeating structural unit having an ether bond and a sulfonyl group. It should be noted that in the present invention, component (B) does not include the following amorphous thermoplastic resin, which contains a repeating structural unit having an ether bond, a sulfonyl group, and an imide bond.

[0126] As the polyethersulfone resin (B), from the viewpoint of obtaining good heat resistance and toughness, it preferably contains at least one aromatic ring or alicyclic hydrocarbon structure, and more preferably contains an aromatic ring. The definitions of the aromatic ring and alicyclic hydrocarbon structure are the same as those described above.

[0127] As the polyethersulfone resin (B), a resin containing a repeating structural unit represented by the following formula (4) can be exemplified.

[0128]

[0129] (R 41 and R 42 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. R 43 is a divalent group containing an ether bond. p 41 and p 42 are each independently an integer from 0 to 4.)

[0130] R 41 and R 42 are preferably alkyl groups having 1 to 4 carbon atoms, and more preferably methyl groups.

[0131] R 43 is preferably a divalent group represented by -O-(CH2)m 42 -, m 42 is preferably from 0 to 4, more preferably from 0 to 3, and further preferably 0.

[0132] p 41 and p 42 are preferably from 0 to 2, and more preferably 0.

[0133] As the polyethersulfone resin (B), resins having the structure represented by the following formula (I) are more preferably exemplified.

[0134]

[0135] In the formula, R represents a terminal group, which is Cl or OH. n represents the average number of repeating structural units and is a number of 2 or more.

[0136] From the viewpoint of exhibiting higher toughness, R in the formula (I) is preferably Cl. It should be noted that when R in the formula (I) contains OH, it becomes a reactive polyethersulfone resin.

[0137] From the viewpoint of obtaining good heat resistance and toughness, the glass transition temperature of the polyethersulfone resin (B) is preferably 210 °C or higher, more preferably 215 °C or higher, and from the viewpoint of moldability, it is preferably 280 °C or lower, more preferably 260 °C or lower.

[0138] The glass transition temperature can be measured by the same method as described above.

[0139] From the viewpoint of obtaining good heat resistance and toughness, the intrinsic viscosity of the polyethersulfone resin (B) at 25 °C is preferably 0.20 to 1.00 dL / g, more preferably 0.25 to 1.00 dL / g, further preferably 0.30 to 0.80 dL / g, and even more preferably 0.35 to 0.60 dL / g.

[0140] The intrinsic viscosity of the polyethersulfone resin (B) is based on the method of JIS K7367-5:2000. Specifically, it can be measured by the method described in the examples. For the above-mentioned intrinsic viscosity, it is preferable that the value measured at 25 °C for the polyethersulfone resin powder that has not been provided with a heat history by melting or the like falls within the above range.

[0141] From the viewpoint of obtaining good heat resistance and toughness, the number average molecular weight (Mn) of the polyethersulfone resin (B) is preferably 2,000 to 25,000, more preferably 3,000 to 25,000, further preferably 3,500 to 25,000, even more preferably 3,500 to 25,000, and even more preferably 5,000 to 20,000.

[0142] From the viewpoint of obtaining good heat resistance and toughness, the weight average molecular weight (Mw) of the polyethersulfone resin (B) is preferably 5,000 to 80,000, more preferably 7,000 to 80,000, further preferably 8,000 to 80,000, even more preferably 8,000 to 60,000, even more preferably 10,000 to 55,000, and even more preferably 12,000 to 55,000.

[0143] The number-average molecular weight and weight-average molecular weight of the polyethersulfone resin (B) can be measured by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) as a standard sample. Specifically, they can be measured by the method described in the examples. The values of the above-mentioned number-average molecular weight and weight-average molecular weight preferably fall within the above range when measured using polyethersulfone resin powder that has not been provided with a thermal history such as by melting.

[0144] One type of the polyethersulfone resin (B) can be used alone, or two or more types can be used in combination. The form of the polyethersulfone resin (B) is not particularly limited, and either powder or pellets can be used. However, from the viewpoints of improving the dispersibility in the polyimide resin (A) and maintaining the properties in a state without a thermal history such as melting, powder is more preferred.

[0145] As the polyethersulfone resin (B), commercially available products can also be used. Examples of commercially available polyethersulfone resins include the "Sumikaexcel PES" series (3600P, 4100P, 4800P, 5200P, 5400P, 5900P, 7600P, 5003P, 5003MPS, 3600G, 4100G, 4800G) manufactured by Sumitomo Chemical Co., Ltd., and the "ULTRAZONE E" series (E1010, E2010, E2020P, E3010, E6020P) manufactured by BASF Corporation, etc.

[0146] From the viewpoint of obtaining good toughness, the mass ratio [(A) / (B)] of the polyimide resin (A) to the polyethersulfone resin (B) in the polyimide resin composition of the present invention is 0.1 / 99.9 to 65 / 35, preferably 1 / 99 to 65 / 35, more preferably 5 / 95 to 65 / 35, further preferably 10 / 90 to 65 / 35, still further preferably 15 / 85 to 60 / 40, still further preferably 20 / 80 to 60 / 40, still further preferably 25 / 75 to 60 / 40, still further preferably 25 / 75 to 55 / 45.

[0147] In addition, from the viewpoint of obtaining the effects of the present invention, the total content of the polyimide resin (A) and the polyethersulfone resin (B) in the polyimide resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, still further preferably 90% by mass or more. In addition, the upper limit is 100% by mass.

[0148] <Additive>

[0149] The polyimide resin composition of the present invention may contain additives such as a filler, a reinforcing fiber, a matting agent, a nucleating agent, a plasticizer, an antistatic agent, an anti-coloring agent, an anti-gelling agent, a flame retardant, a coloring agent, a sliding property improver, an antioxidant, an ultraviolet absorber, a conductive agent, and a resin modifier, as needed.

[0150] There is no particular limitation on the content of the above additives. From the viewpoint of maintaining the physical properties of the polyimide resin (A) and the polyethersulfone resin (B) and exhibiting the effects of the additives, in the polyimide resin composition, it is usually 50% by mass or less, preferably 0.0001 to 30% by mass, more preferably 0.0001 to 15% by mass, and further preferably 0.001 to 10% by mass.

[0151] The polyimide resin composition of the present invention can take any form, but pellets are preferred.

[0152] Since the polyimide resin (A) and the polyethersulfone resin (B) are thermoplastic, for example, by melt-kneading the polyimide resin (A), the polyethersulfone resin (B), and various optional components as needed in an extruder, extruding a strand, and cutting the strand, pelletization can be carried out. In addition, by introducing the obtained pellets into various molding machines and performing thermoforming by the method described below, a molded body having a desired shape can be easily manufactured.

[0153] From the viewpoint of heat resistance, the glass transition temperature of the polyimide resin composition of the present invention is preferably 160 °C or higher, more preferably 170 °C or higher, and from the viewpoint of exhibiting high moldability, it is preferably 250 °C or lower, more preferably 240 °C or lower, and further preferably 230 °C or lower. The glass transition temperature can be measured by the same method as described above.

[0154] <Tensile properties>

[0155] According to the polyimide resin composition of the present invention, a molded body with further improved toughness can be provided as compared with the case of using only the polyimide resin (A) or only the polyethersulfone resin (B).

[0156] For example, regarding the tensile fracture strain, for a 1A type test piece specified in JIS K7161-2:2014 obtained by molding the polyimide resin composition, the tensile fracture strain measured by a tensile test based on JIS K7161-1:2014 and K7161-2:2014 at a temperature of 23 °C, a clamp distance of 50 mm, and a test speed of 5 mm / minute is preferably 50% or more, more preferably 70% or more, and further preferably 90% or more. The tensile fracture strain can be specifically measured by the method described in the examples.

[0157] <Flexural properties>

[0158] The polyimide resin composition of the present invention can maintain bending properties at a high level and improve toughness as described above. Regarding the bending properties, for a molded body of 80 mm × 10 mm × 4 mm in thickness specified in ISO 316 obtained by molding the polyimide resin composition, the flexural strength measured by performing a flexural test based on ISO 178:2010 at a temperature of 23°C and a test speed of 2 mm / minute can be 100 MPa or more, and the flexural modulus can be 2.2 GPa or more. The flexural strength and flexural modulus can be specifically measured by the methods described in the examples.

[0159] <Other properties>

[0160] The polyimide resin composition according to the present invention can produce a molded body with high whiteness compared to the case of using only the polyimide resin (A) and only the polyethersulfone resin (B). Therefore, the polyimide resin composition and the molded body of the present invention are also expected to be applicable to reflectors and the like. In addition, the polyimide resin composition of the present invention has the properties of the polyimide resin (A) which is a crystalline thermoplastic resin, and thus has good chemical resistance.

[0161] [Molded body]

[0162] The present invention provides a molded body containing the aforementioned polyimide resin composition.

[0163] Since the polyimide resin composition of the present invention has thermoplasticity, the molded body of the present invention can be easily manufactured by thermoforming. Examples of the thermoforming method include injection molding, extrusion molding, blow molding, hot pressing, vacuum molding, pressure air molding, laser molding, welding, fusion welding, etc., and any method can be used as long as it is a molding method that goes through a hot melting process.

[0164] The molding temperature also varies depending on the thermal properties (melting point and glass transition temperature) of the polyimide resin composition. For example, in injection molding, it can be molded at a molding temperature of less than 400°C and a mold temperature of 220°C or less.

[0165] As a method for manufacturing the molded body, a step of thermoforming the polyimide resin composition at a temperature of less than 400°C is preferably included. As a specific procedure, for example, the following methods can be cited.

[0166] First, a polyether sulfone resin (B) and various optional components as needed are added to a polyimide resin (A) and dry-blended, and then the mixture is introduced into an extruder. It is preferably melted at a temperature below 400°C, melt-kneaded and extruded in the extruder to produce pellets. Alternatively, the polyimide resin (A) is introduced into the extruder, preferably melted at a temperature below 400°C, and the polyether sulfone resin (B) and various optional components are introduced therein. The polyimide resin (A) is melt-kneaded and extruded in the extruder, whereby the aforementioned pellets can be produced.

[0167] After drying the above pellets, they are introduced into various molding machines and preferably thermoformed at a temperature below 400°C to produce a molded article having a desired shape.

[0168] The molded article of the present invention has excellent heat resistance, bending characteristics and high toughness, and thus is expected to be applied to uses that emphasize impact resistance, vibration damping properties, etc. For example, it can be applied to uses such as sliding members such as gears and bearings, cutting members, structural members such as robotic arms, winding coating materials such as electric wires, screws, nuts, seals, diaphragms for speakers, reflectors, components related to the fifth-generation mobile communication system (5G), various films, etc. In addition, it can also be expected to be applied to uses such as water treatment membranes for the same uses as polyether sulfone resins.

[0169] Examples

[0170] Next, examples are given to illustrate the present invention in more detail, but the present invention is not limited thereto. In addition, various measurements and evaluations in each production example and example are carried out as follows.

[0171] <Infrared spectroscopy (IR measurement)>

[0172] The IR measurement of the polyimide resin was carried out using "JIR-WINSPEC50" manufactured by JEOL Ltd.

[0173] <Logarithmic viscosity μ>

[0174] After drying the polyimide resin at 190 to 200°C for 2 hours, a polyimide resin solution in which 0.100 g of the polyimide resin was dissolved in 20 mL of concentrated sulfuric acid (96%, manufactured by Kanto Chemical Co., Inc.) was used as a measurement sample, and the measurement was carried out at 30°C using a Cannon-Fenske viscometer. The logarithmic viscosity μ was calculated according to the following formula.

[0175] μ = ln[(ts / t0) / C]

[0176] t0: Flow time of concentrated sulfuric acid

[0177] ts: Flow time of polyimide resin solution

[0178] C: 0.5 g / dL

[0179] <Melting point, glass transition temperature, crystallization temperature, heat of crystallization>

[0180] The melting point Tm, glass transition temperature Tg, crystallization temperature Tc, and heat of crystallization ΔHm of the polyimide resin, polyethersulfone resin, or the polyimide resin composition produced in each example were measured using a differential scanning calorimeter device ("DSC-6220" manufactured by SII NanoTechnology Inc.).

[0181] Under a nitrogen atmosphere, a thermal history under the following conditions was applied to the polyimide resin, polyethersulfone resin, or polyimide resin composition. The conditions of the thermal history are as follows: first heating (heating rate 10 °C / min), then cooling (cooling rate 20 °C / min), and then second heating (heating rate 10 °C / min).

[0182] 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. It should be noted that for Tm, Tg, and Tc, in the case where multiple peaks are observed, the peak top values of each peak are read.

[0183] In addition, the heat of crystallization ΔHm (mJ / mg) was calculated from the area of the exothermic peak observed during cooling.

[0184] <Half crystallization time>

[0185] The half crystallization time of the polyimide resin was measured using a differential scanning calorimeter device ("DSC-6220" manufactured by SII NanoTechnology Inc.).

[0186] After maintaining the polyimide resin at 420 °C for 10 minutes in a nitrogen atmosphere to completely melt it, when performing a quenching operation with a cooling rate of 70 °C / min, the time required from the appearance of the observed crystallization peak to reaching the peak top value was calculated. It should be noted that in Table 1, cases where the half crystallization time is 20 seconds or less are marked as "<20".

[0187] <Weight average molecular weight and number average molecular weight>

[0188] The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polyimide resin and polyethersulfone resin were measured using a gel permeation chromatography (GPC) measuring device "Shodex GPC-101" manufactured by Showa Denko K.K. under the following conditions. For the polyethersulfone resin, polyethersulfone resin powder was used as the measurement sample.

[0189] Column: Shodex HFIP-806M

[0190] Mobile phase solvent: Hexafluoroisopropanol (HFIP) containing 2 mM sodium trifluoroacetate

[0191] Column temperature: 40 °C

[0192] Flow rate of mobile phase: 1.0 mL / minute

[0193] Sample concentration: Approximately 0.1% by mass

[0194] Detector: IR detector

[0195] Injection volume: 100 μm

[0196] Standard curve: Standard PMMA

[0197] <Intrinsic viscosity [η]>

[0198] The intrinsic viscosity of the polyethersulfone resin is measured by the following method based on JIS K7367-5:2000. Note that polyethersulfone resin powder is used as the measurement sample.

[0199] Solutions of polyethersulfone resin with concentrations of 0.5 g / dL, 1.0 g / dL, and 1.5 g / dL in N,N-dimethylformamide were prepared. For this solution, in a constant temperature bath at 25 ± 0.05 °C, the viscosity was measured 3 times respectively using an Ubbelohde viscometer (No. 0B), and the reduced viscosity (unit: dL / g) was calculated based on the average value. A standard curve was plotted with the concentration (g / dL) of the polyethersulfone resin on the horizontal axis and the reduced viscosity (dL / g) on the vertical axis, and the viscosity value extrapolated to a concentration of 0 g / dL was taken as the value of the intrinsic viscosity (unit: dL / g).

[0200] <Heat distortion temperature (HDT)>

[0201] Using polyimide resin, polyethersulfone resin, or the polyimide resin composition manufactured in each example, a molded body of 80 mm × 10 mm × thickness 4 mm was manufactured by the method described later for measurement.

[0202] The measurement is based on JIS K7191-1,2:2015, and the test under Flatwise is carried out. Specifically, using an HDT test device "Auto-HDT3D-2" (manufactured by Toyo Seiki Seisaku-sho, Ltd.), the heat distortion temperature is measured under the conditions of a fulcrum spacing of 64 mm, a load of 1.80 MPa, and a heating rate of 120 °C / hour.

[0203] <Flexural strength and flexural modulus>

[0204] Using a polyimide resin, a polyethersulfone resin, or the polyimide resin composition produced in each example, a molded body of 80 mm × 10 mm × 4 mm in thickness specified in ISO 316 was produced by the method described below for measurement. Using a Bend Graph (manufactured by Toyo Seiki Seisaku-sho, Ltd.), a bending test was conducted based on ISO 178:2010 at a temperature of 23°C and a test speed of 2 mm / minute to measure the flexural strength and flexural modulus.

[0205] <Tensile strength, tensile modulus, and tensile fracture strain>

[0206] Using a polyimide resin, a polyethersulfone resin, or the polyimide resin composition produced in each example, a No. 1A test piece specified in JIS K7161-2:2014 was produced by the method described below for measurement. Using a tensile testing machine (“Strograph VG-1E” manufactured by Toyo Seiki Co., Ltd.), a tensile test was conducted based on JIS K7161-1:2014 and K7161-2:2014 at a temperature of 23°C, a grip distance of 50 mm, and a test speed of 5 mm / minute to measure the tensile strength, tensile modulus, and tensile fracture strain.

[0207] <Hue>

[0208] Pellets of the polyimide resin, polyethersulfone resin, or the polyimide resin composition produced in each example were used for measurement.

[0209] Using a color difference meter (“ZE2000” manufactured by Nippon Denshoku Industries Co., Ltd.), the Lab value and YI value were measured by the reflection method. In addition, the whiteness was calculated based on the Lab value and YI value.

[0210] It should be noted that the Lab value was measured based on the method of JIS Z8781-4:2013, the YI value was measured based on the method of JIS K7373:2006, and the whiteness was calculated based on the method of JIS Z8715:1999.

[0211] Production Example 1 (Production of Polyimide Resin 1)

[0212] Into a 2 L detachable flask equipped with a Dean-Stark trap, a Liebig condenser, a thermocouple, and 4 paddle blades, 500 g of 2-(2-methoxyethoxy)ethanol (manufactured by Nippon Emulsifier Co., Ltd.) and 218.12 g (1.00 mol) of pyromellitic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Inc.) were introduced. After purging with nitrogen, the mixture was stirred at 150 rpm to form a homogeneous suspension solution. On the other hand, in a 500 mL beaker, 49.79 g (0.35 mol) of 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Inc., cis / trans ratio = 7 / 3) and 93.77 g (0.65 mol) of 1,8-octamethylenediamine (manufactured by Kanto Chemical Co., Inc.) were dissolved in 250 g of 2-(2-methoxyethoxy)ethanol to prepare a mixed diamine solution. This mixed diamine solution was slowly added using a piston pump. Exotherm occurred during the dropping, but the internal temperature was adjusted to fall within 40 - 80 °C. The entire process of dropping the mixed diamine solution was under a nitrogen purge state, and the stirring blade speed was set to 250 rpm. After the dropping was completed, 130 g of 2-(2-methoxyethoxy)ethanol and 1.284 g (0.010 mol) of n-octylamine (manufactured by Kanto Chemical Co., Inc.) as a capping agent were added, and further stirred. At this stage, a pale yellow polyamic acid solution was obtained. Then, after setting the stirring speed to 200 rpm, the polyamic acid solution in the 2 L detachable flask was heated to 190 °C. During the gradual heating process, precipitation of polyimide resin powder and dehydration accompanied by imidization were confirmed between the liquid temperatures of 120 - 140 °C. After holding at 190 °C for 30 minutes, it was naturally cooled to room temperature and filtered. The obtained polyimide resin powder was washed with 300 g of 2-(2-methoxyethoxy)ethanol and 300 g of methanol, filtered, and then dried in a dryer at 180 °C for 10 hours to obtain 317 g of powder of crystalline thermoplastic polyimide resin 1 (hereinafter, simply referred to as "polyimide resin 1").

[0213] The IR spectrum of polyimide resin 1 was measured, and as a result, characteristic absorptions of the imide ring were confirmed at ν(C=O) 1768, 1697 (cm -1 ). The logarithmic viscosity was 1.30 dL / g, Tm was 323 °C, Tg was 184 °C, Tc was 266 °C, the heat of crystallization was 21.0 mJ / mg, the half-crystallization time was 20 seconds or less, and Mw was 55,000.

[0214] The composition and evaluation results of polyimide resin 1 in Production Example 1 are shown in Table 1. It should be noted that the mol% of the tetracarboxylic acid component and the diamine component in Table 1 are values calculated based on the input amounts of the respective components during the manufacture of the polyimide resin.

[0215] [Table 1]

[0216]

[0217] *1: With respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) in polyimide resin 1,

[0218] Content ratio (mol%) of the repeating structural unit of formula (1)

[0219] The abbreviations in Table 1 are as follows.

[0220] ·PMDA; Pyromellitic dianhydride

[0221] ·1,3 - BAC; 1,3 - Bis(aminomethyl)cyclohexane

[0222] ·OMDA; 1,8 - Octamethylenediamine

[0223] Examples 1 - 2, Comparative Examples 1 - 2 (Production and evaluation of polyimide resin compositions and molded articles)

[0224] The powder of polyimide resin 1 obtained in Production Example 1 and the powder of polyethersulfone resin (B1) ("Sumikaexcel 3600P" manufactured by Sumitomo Chemical Co., Ltd., intrinsic viscosity at 25°C: 0.307 dL / g, Mn: 8,600, Mw: 16,500, Tg: 222°C) were dry - mixed in the proportions shown in Table 2, and then melt - kneaded and extruded using a co - rotating twin - screw kneading extruder ("HK - 25D" manufactured by Parker Corporation, screw diameter 25 mmΦ, L / D = 41) under the conditions of a barrel temperature of 370°C and a screw rotation speed of 150 rpm. The strand extruded from the extruder was air - cooled and then pelletized using a pelletizer ("Fine cutter FC - Mini - 4 / N" manufactured by Hoshi Plastics Co., Ltd.). The obtained pellets were dried at 150°C for 12 hours and then used for injection molding.

[0225] Using an injection molding machine ("Roboshotα - S30iA" manufactured by FANUC CORPORATION), injection molding was carried out at a barrel temperature of 385°C, a mold temperature of 165°C, and a molding cycle of 60 seconds to produce molded articles of a specified shape for various evaluations.

[0226] Using the obtained pellets and molded articles, various evaluations were carried out according to the aforementioned method. The results are shown in Table 2.

[0227] Examples 3 - 5, Comparative Examples 3 - 4 (Production and evaluation of polyimide resin compositions and molded articles)

[0228] The powder of the polyimide resin 1 obtained in Production Example 1 and the powder of the polyethersulfone resin (B2) ("Sumikaexcel 4800P" manufactured by Sumitomo Chemical Co., Ltd., intrinsic viscosity at 25°C: 0.389 dL / g, Mn: 7,200, Mw: 16,200, Tg: 221°C) were used in the proportions shown in Table 2. Except for this, pellets and molded articles were produced in the same manner as in Examples 1 to 2 and Comparative Examples 1 to 2, and various evaluations were carried out. The results are shown in Table 2.

[0229] Reference Example 1

[0230] The powder of the polyethersulfone resin (B1) ("Sumikaexcel 3600P" manufactured by Sumitomo Chemical Co., Ltd.) was melt-kneaded and extruded using a granulator (manufactured by Toyo Seiki Seisaku-sho, Ltd.) at a barrel temperature of 360°C and a screw rotation speed of 150 rpm. After the strand extruded from the extruder was air-cooled, it was granulated using a granulator ("Finecutter FC-Mini-4 / N" manufactured by Hoshi Plastics Co., Ltd.). The obtained pellets were dried at 160°C for 6 hours and then used for injection molding.

[0231] Using an injection molding machine ("Roboshotα-S30iA" manufactured by FANUC CORPORATION), injection molding was carried out at a barrel temperature of 350°C, a mold temperature of 180°C, and a molding cycle of 60 seconds to produce molded articles of a specified shape for various evaluations.

[0232] Using the obtained pellets and molded articles, various evaluations were carried out according to the aforementioned method. The results are shown in Table 2.

[0233] Reference Example 2

[0234] In Reference Example 1, the powder of the polyethersulfone resin (B2) ("Sumikaexcel 4800P" manufactured by Sumitomo Chemical Co., Ltd.) was used instead of the powder of the polyethersulfone resin (B1). Except for this, pellets and molded articles were produced in the same manner as in Reference Example 1, and various evaluations were carried out. The results are shown in Table 2.

[0235] Reference Example 3

[0236] The powder of the polyimide resin 1 obtained in Production Example 1 was melt-kneaded and extruded using a granulator (manufactured by Toyo Seiki Seisaku-sho, Ltd.) at a barrel temperature of 360°C and a screw rotation speed of 150 rpm. After the strand extruded from the extruder was air-cooled, it was granulated using a granulator ("Fine cutter FC-Mini-4 / N" manufactured by Hoshi Plastics Co., Ltd.). The obtained pellets were dried at 150°C for 12 hours and then used for injection molding.

[0237] Using an injection molding machine (“Roboshot α-S30iA” manufactured by FANUC CORPORATION), injection molding was carried out at a barrel temperature of 350 °C, a mold temperature of 200 °C, and a molding cycle of 50 seconds to produce a molded body of a specified shape for various evaluations.

[0238] Using the obtained pellets and molded body, various evaluations were carried out according to the aforementioned method. The results are shown in Table 2.

[0239] [Table 2]

[0240]

[0241] The details of each component shown in Table 2 are as follows.

[0242] [Polyimide resin (A)]

[0243] (A1) Polyimide resin 1: Crystalline thermoplastic polyimide resin 1 obtained in Production Example 1

[0244] [Polyethersulfone resin (B)]

[0245] (B1) Polyethersulfone resin (3600P): “Sumikaexcel 3600P” manufactured by Sumitomo Chemical Co., Ltd., R = Cl in formula (I), intrinsic viscosity at 25 °C: 0.307 dL / g, Mn: 8,600, Mw: 16,500, Tg: 222 °C

[0246] (B2) Polyethersulfone resin (4800P): “Sumikaexcel 4800P” manufactured by Sumitomo Chemical Co., Ltd., R = Cl in formula (I), intrinsic viscosity at 25 °C: 0.389 dL / g, Mn: 7,200, Mw: 16,200, Tg: 221 °C

[0247] As shown in Table 2, the molded bodies composed of the polyimide resin compositions of Examples 1 to 2 containing polyimide resin (A1) and polyethersulfone resin (B1) in a mass ratio range of 0.1 / 99.9 to 65 / 35 had improved tensile fracture strain compared to the molded bodies of Comparative Examples 1 and 2 where the ratio of polyimide resin (A1) to polyethersulfone resin (B1) was outside the above range, Reference Example 1 composed only of polyethersulfone resin (B1), and Reference Example 3 composed only of polyimide resin (A1).

[0248] Similarly, the molded bodies composed of the polyimide resin compositions of Examples 3 to 5 containing polyimide resin (A1) and polyethersulfone resin (B2) in a mass ratio range of 0.1 / 99.9 to 65 / 35 showed improved tensile fracture strain compared to the molded bodies of Comparative Examples 3 and 4 where the ratio of polyimide resin (A1) to polyethersulfone resin (B2) was outside the above range, Reference Example 2 composed only of polyethersulfone resin (B2), and Reference Example 3 composed only of polyimide resin (A1).

[0249] In addition, it was found that for the polyimide resin compositions of Examples 1 to 5, the L value and whiteness were higher compared to the polyimide resin compositions of the comparative examples and the resins of the reference examples.

[0250] In addition, using the pellets obtained in Example 1, Example 2, and Comparative Example 1, the dispersion state of polyimide resin (A1) and polyethersulfone resin (B1) in each pellet was confirmed by the following method.

[0251] As Figure 1 shown, each pellet was cut parallel to the flow direction of the pellet (MD) (i.e., in a manner to expose the TD cross-section) using a microtome ("ULTRACUT E" manufactured by REICHERT-JUNG LIMITED) to produce ultra-thin sections. In Figure 1 , 1 is the pellet and 2 is the ultra-thin section.

[0252] After staining the cut surface with ruthenium tetroxide in the gas phase for 30 minutes, it was observed using a field emission scanning transmission electron microscope (FE-STEM, "GeminiSEM500" manufactured by ZEISS) at an acceleration voltage of 30 kV and an observation magnification of 5000 times ( Figures 2 to 4 ). In each observation image, it was determined that the darker-colored parts were composed of polyethersulfone resin (B1) that was easily stained by ruthenium tetroxide.

[0253] Figure 2 are the micrographs of the pellets of Example 1 (mass ratio [(A1) / (B1)] = 30 / 70), Figure 3 are the micrographs of the pellets of Example 2 (mass ratio [(A1) / (B1)] = 50 / 50), Figure 4 are the micrographs of the pellets of Comparative Example 1 (mass ratio [(A1) / (B1)] = 70 / 30).

[0254] According to Figures 2 to 4 , it was found that in the pellets obtained in Example 1, Example 2, and Comparative Example 1, polyimide resin (A1) and polyetherimide sulfone resin (B1) were uniformly dispersed, and a sea-island structure with polyimide resin (A1) as the "island" and polyetherimide sulfone resin (B1) as the "sea" was formed as the basic structure. In addition, a morphology with a lake formed in the island or a morphology with a bridge between islands can also be formed.

[0255] It should be noted that, as a control, in Figure 5 microscopic pictures observed by FE-STEM are shown, which use the pellets composed only of the polyethersulfone resin (B1) obtained in Reference Example 1, produce ultrathin sections by the same method as described above, and do not use ruthenium tetroxide for staining.

[0256] Industrial applicability

[0257] Since the polyimide resin composition and the molded article of the present invention are excellent in heat resistance, bending characteristics, and high toughness, they are expected to be applied to uses that value impact resistance, vibration damping properties, etc. For example, they can be applied to uses such as sliding members such as gears and bearings, cutting members, structural members such as robotic arms, wire covering materials such as wires, screws, nuts, seals, speaker diaphragms, reflectors, components related to the fifth-generation mobile communication system (5G) and the sixth-generation mobile communication system (6G), various films, etc. In addition, it can also be expected to be applied to uses such as water treatment membranes for the same uses as polyethersulfone resins.

Claims

1. A polyimide resin composition comprising a crystalline thermoplastic polyimide resin (A) and a polyethersulfone resin (B), wherein the crystalline thermoplastic polyimide resin (A) comprises a repeating structural unit represented by the following formula (1) and a repeating structural unit represented by the following formula (2), and the content ratio of the repeating structural unit of formula (1) is 20 to 70 mol% based on the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2), and the mass ratio of component (A) to component (B), i.e., (A) / (B), is 0.1 / 99.9 to 65 / 35. R1 is a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure, R2 is a divalent linear aliphatic group having 5 to 16 carbon atoms, and X1 and X2 are each independently a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.

2. The polyimide resin composition according to claim 1, wherein, The polyethersulfone resin (B) is a resin having a structure represented by the following formula (I). In the formula, R represents a terminal group, which is Cl or OH, and n represents the average number of repeating structural units, which is a number of 2 or more.

3. The polyimide resin composition according to claim 1 or 2, wherein, The mass ratio of the crystalline thermoplastic polyimide resin (A) to the polyethersulfone resin (B), i.e., (A) / (B), is 10 / 90 to 65 / 35.

4. The polyimide resin composition according to claim 1 or 2, wherein The mass ratio of the crystalline thermoplastic polyimide resin (A) to the polyethersulfone resin (B), i.e., (A) / (B), is 15 / 85 to 65 / 35.

5. The polyimide resin composition according to claim 1 or 2, wherein, The mass ratio of the crystalline thermoplastic polyimide resin (A) to the polyethersulfone resin (B), i.e., (A) / (B), is 30 / 70 to 65 / 35.

6. The polyimide resin composition according to claim 1 or 2, wherein The mass ratio of the crystalline thermoplastic polyimide resin (A) to the polyethersulfone resin (B), i.e., (A) / (B), is 15 / 85 to 60 / 40.

7. The polyimide resin composition according to claim 1 or 2, wherein, The polyethersulfone resin (B) has an intrinsic viscosity at 25°C of 0.20 to 1.00 dL / g.

8. A molded article comprising the polyimide resin composition according to any one of claims 1 to 7.

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