Aromatic polysulfone and heat-resistant film

Abstract

This aromatic polysulfone comprises a repeating unit S1 represented by formula (S1) and a repeating unit S2 represented by formula (S2). In formula (S1), R1 and R2 each independently represent a hydrogen atom or an alkyl group. In formula (S2): R5 and R6 each independently represent a halogen atom, a phenyl group, an alkyl group having 1-6 carbon atoms, or an alkenyl group having 2-10 carbon atoms; m and n each independently represent an integer of 0-4; and when there are multiple R5s or R6s, these moieties may be the same or different.

Description

Aromatic polysulfone and heat-resistant film

[0001] This disclosure relates to aromatic polysulfones and heat-resistant films. This application claims priority to Japanese Patent Application No. 2024-036331, filed on March 8, 2024, the contents of which are incorporated herein by reference.

[0002] Aromatic polysulfone has a high glass transition temperature (Tg) and is used in many fields, including electronic materials, as a material with excellent heat resistance. For example, Patent Document 1 discloses that a resin film made from an aromatic polysulfone having a bisphenol fluorene structure has excellent transparency, dielectric properties, and mechanical properties.

[0003] Japanese Patent Application Laid-Open No. 2003-321556

[0004] Molded articles made of aromatic polysulfone that are used in high-temperature environments are required to have stable dimensions without significant thermal expansion even in high-temperature environments. In the following description, the property of small dimensional changes with temperature changes is referred to as "dimensional stability." The aromatic polysulfone described in Patent Document 1 has room for improvement in terms of dimensional stability in high-temperature environments.

[0005] An object of the present disclosure is to provide an aromatic polysulfone that can be molded into a molded article having a small linear expansion coefficient and excellent dimensional stability, and a heat-resistant film that exhibits excellent dimensional stability in a high-temperature environment.

[0006] The present disclosure encompasses the following aspects.

[0007] [1] An aromatic polysulfone comprising a repeating unit S1 represented by the following formula (S1) and a repeating unit S2 represented by the following formula (S2): (In formula (S1), R １ and R ２ each independently represents a hydrogen atom or an alkyl group. (In formula (S2), R ５ and R ６each independently represents a halogen atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; m and n each independently represent an integer of 0 to 4; R ５ or R ６ If there are multiple, they may be the same or different)

[0008] [2] An aromatic polysulfone in which the content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone is 5 mol % or more.

[0009] [3] A heat-resistant film containing the aromatic polysulfone according to [1] or [2].

[0010] According to the present disclosure, it is possible to provide an aromatic polysulfone that can be molded into a molded article having a small linear expansion coefficient and excellent dimensional stability, and also to provide a heat-resistant film that exhibits excellent dimensional stability in a high-temperature environment.

[0011] <<Aromatic Polysulfone>> The aromatic polysulfone of the present embodiment includes a repeating unit S1 represented by the following formula (S1) and a repeating unit S2 represented by the following formula (S2). (In formula (S1), R １ and R ２ each independently represents a hydrogen atom or an alkyl group. (In formula (S2), R ５ and R ６ each independently represents a halogen atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; m and n each independently represent an integer of 0 to 4; R ５ or R ６ If there are multiple, they may be the same or different)

[0012] [Repeating unit S1] In the above formula (S1), R １ and R ２ The alkyl group in R may be an alkyl group having 1 to 6 carbon atoms. １ and R ２The alkyl group in may be linear or branched, and specific examples include a methyl group, an ethyl group, a 1-propyl group, an isopropyl group, a 1-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and an n-hexyl group.

[0013] R １ and R ２ are preferably all hydrogen atoms.

[0014] The repeating unit S1 has a spiro structure. Therefore, it is believed that aromatic polysulfones having the repeating unit S1 have restricted molecular chain movement and exhibit a high glass transition temperature. Furthermore, the monomers from which the repeating unit S1 is derived (compounds of the following formula (S1a) or (S1b)) are less likely to decompose during polymerization due to their closed ring structure (particularly the spiro structure) compared to when a monomer not having a spiro structure, such as that shown in the following formula (X), is used. Similarly, aromatic polysulfones having the repeating unit S1 have high heat resistance due to their spiro structure.

[0015]

[0016] (In formula (S1b), X １ and X ２ each independently represents a halogen atom; １ and X ２ may be the same or different)

[0017] (In formulas (S1a), (S1b) and (X), R １ and R ２ is R in the above formula (S1). １ and R ２ (synonymous with

[0018] Furthermore, in the repeating unit S1, the structure is fixed in a state where the fluorene ring is perpendicular to the xanthene ring. Therefore, around the repeating unit S1, the molecular chain is difficult to crystallize due to the steric hindrance caused by the fluorene ring, and the polymer as a whole tends to become amorphous. Therefore, molded articles made from aromatic polysulfone having the repeating unit S1 tend to have transparency.

[0019] These effects are due to the structure of the "repeating unit S1 represented by formula (S1)." Therefore, it is believed that any aromatic polysulfone containing the "repeating unit S1 represented by formula (S1)" can achieve the same effects as those of the present disclosure, even if the types of other repeating units are different.

[0020] The content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone is preferably 5 mol % or more, and may be 10 mol % or more. When the content is 5 mol % or more, the linear expansion coefficient of the resulting aromatic polysulfone can be sufficiently reduced. As a result, a molded article containing the aromatic polysulfone has excellent dimensional stability in a high-temperature environment.

[0021] The content of the repeating unit S1 is preferably, for example, 50 mol % or less, that is, the content of the repeating unit S1 is preferably 5 mol % or more and 50 mol % or less, and may be 10 mol % or more and 50 mol % or less.

[0022] [Repeating unit S2] In the above formula (S2), R ５ and R ６ The alkyl group in may be linear or branched, and specific examples include a methyl group, an ethyl group, a 1-propyl group, an isopropyl group, a 1-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and an n-hexyl group.

[0023] In the above formula (S2), R ５ and R ６ The alkenyl group in formula (1) is R １ and R ２ In the alkyl groups exemplified above, one single bond (C-C) between carbon atoms is substituted with a double bond (C=C), and the position of the double bond is not limited.

[0024] In the above formula (S2), m and n are each preferably 0, and m and n may be 0 at the same time.

[0025] The aromatic polysulfone preferably has a content of repeating unit S2 of 50 mol% or more relative to all repeating units constituting the aromatic polysulfone. Furthermore, the content of repeating unit S2 relative to all repeating units is preferably 95 mol% or less, and may be 90 mol% or less. The content of repeating unit S2 relative to all repeating units may be 50 mol% or more and 95 mol% or less, or may be 50 mol% or more and 90 mol% or less. Here, the sum of the content of repeating unit S1 and the content of repeating unit S2 does not exceed 100 mol%. In one embodiment of the aromatic polysulfone, the content of repeating unit S1 is 5 mol% or more and 50 mol% or less, and the content of repeating unit S2 is 50 mol% or more and 95 mol% or less. In another embodiment of the aromatic polysulfone, the content of the repeating unit S1 is 10 mol % or more and 50 mol % or less, and the content of the repeating unit S2 is 50 mol % or more and 90 mol % or less.

[0026] The aromatic polysulfone may have a repeating unit derived from the monomer represented by the above formula (X) within a range that does not impair the effects of the present disclosure.

[0027] The aromatic polysulfone may have other repeating units in addition to the repeating unit S1 and the repeating unit S2. The aromatic polysulfone preferably has only the repeating unit S1 and the repeating unit S2.

[0028] The aromatic polysulfone having the repeating unit S1 can exhibit a high glass transition temperature (Tg) and is excellent in heat resistance. The glass transition temperature of the aromatic polysulfone can be measured by the following method.

[0029] [Measurement of Glass Transition Temperature] The glass transition temperature of the aromatic polysulfone is determined by heat flux differential scanning calorimetry in accordance with JIS K7121 (1987). Approximately 10 mg of aromatic polysulfone is precisely weighed and heated to 400°C at a heating rate of 10°C / min under a nitrogen stream, and then cooled to 50°C. The temperature is again raised to 400°C at a heating rate of 10°C / min, and the glass transition temperature Tg of the aromatic polysulfone is calculated from the DSC chart obtained after the second heating. The glass transition temperature is preferably 230°C or higher, more preferably 240°C or higher, even more preferably 250°C or higher, even more preferably 270°C or higher, and even more preferably 300°C or higher.

[0030] The measurement can be performed using a differential scanning calorimeter (for example, DSC-50 manufactured by Shimadzu Corporation).

[0031] The molecular weight of the aromatic polysulfone is evaluated by the reduced viscosity, which can be measured by the following method.

[0032] [Measurement of reduced viscosity] 1 g of aromatic polysulfone is dissolved in N,N-dimethylformamide to a volume of 1 dL (solution concentration: 1 g / dL). The viscosity (η) of the resulting aromatic polysulfone solution is measured at 25°C using an Ostwald-type viscometer.

[0033] In addition, the viscosity (η ０ ) is measured at 25°C using an Ostwald type viscometer. ０ ) to obtain the specific viscosity η ｓｐ = ((η-η ０ ) / η ０ ) is required.

[0034] Specific viscosity η ｓｐis divided by the solution concentration of the aromatic polysulfone solution to determine the reduced viscosity (unit: dL / g). The reduced viscosity is preferably 0.2 dL / g or more, more preferably 0.3 dL / g or more, and even more preferably 0.35 dL / g or more, and is preferably 1.2 dL / g or less, more preferably 1.0 dL / g or less, more preferably 0.8 dL / g or less, and even more preferably 0.6 dL / g or less. The reduced viscosity may be 0.2 dL / g or more and 1.2 dL / g or less, 0.3 dL / g or more and 1.0 dL / g or less, 0.35 dL / g or more and 0.8 dL / g or less, or 0.35 dL / g or more and 0.6 dL / g or less.

[0035] Furthermore, the above-mentioned aromatic polysulfone has a small coefficient of linear expansion, and when molded into a molded article, it has excellent dimensional stability at high temperatures. The coefficient of linear expansion of the aromatic polysulfone can be measured by the following method.

[0036] [Measurement of Linear Expansion Coefficient] (Film Preparation) 20 g of aromatic polysulfone is added to 80 g of N-methyl-2-pyrrolidone and heated to 80°C under a nitrogen stream to completely dissolve, yielding a pale yellow, transparent aromatic polysulfone solution. The resulting solution is cast onto a glass plate (thickness: 3 mm) using a film applicator to form a coating film. The resulting coating film is heated at 250°C under a nitrogen atmosphere in a high-temperature hot air dryer to remove the solvent, yielding a film. The film thickness is 50 μm.

[0037] (Measurement of linear expansion coefficient) The obtained film was cut to prepare a strip-shaped test piece of 25 mm in the casting direction and 5 mm in the direction perpendicular to the casting direction. The obtained test piece was placed in a thermomechanical analyzer and measured for the linear expansion coefficient in the casting direction as the temperature was raised from 150°C to 200°C at a rate of 5°C / min under a nitrogen gas flow.

[0038] A thermomechanical analyzer (e.g., TMA, manufactured by Seiko Electronics Corporation) can be used for the measurement. The chuck distance during measurement is 20 mm, and the test load is 2.5 g. The above measurement is performed twice, and the arithmetic mean value of the obtained measured values ​​is used as the value of the linear expansion coefficient. The linear expansion coefficient is preferably 60 ppm / °C or less, more preferably 58 ppm / °C or less, and even more preferably 55 ppm / °C or less.

[0039] <<Method for Producing Aromatic Polysulfone>> The aromatic polysulfone can be produced by a production method including a step of reacting, in an aprotic polar solvent, monomers containing at least one aromatic dihydroxy compound and at least one aromatic dihalogeno compound. The aromatic dihydroxy compound is represented by formula (S1a) above or formula (S2a) below. The aromatic dihalogeno compound is represented by formula (S1b) above or formula (S2b) below.

[0040]

[0041] (In formula (S2b), X １ and X ２ each independently represents a halogen atom; １ and X ２ may be the same or different, and in formulas (S2a) and (S2b), R ５ , R ６ , m and n are R in the above formula (S2). ５ , R ６ , m and n)

[0042] The step of reacting the monomer is preferably carried out using an alkali metal carbonate. The alkali metal carbonate may be a carbonate, which is a normal salt, a bicarbonate (also called a hydrogen carbonate), which is an acidic salt, or a mixture of both. As the carbonate, sodium carbonate or potassium carbonate is preferably used, and as the hydrogen carbonate, sodium bicarbonate or potassium bicarbonate is preferably used.

[0043] Examples of aprotic polar solvents include dimethyl sulfoxide, 1-methyl-2-pyrrolidone, sulfolane (also known as 1,1-dioxothiane), 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, and diphenyl sulfone.

[0044] The polymerization temperature varies depending on the type of aprotic polar solvent used, but is, for example, about 180°C to 300°C.

[0045] As described above, the compound containing the structure represented by formula (S1) has high heat resistance and is not easily decomposed during polymerization due to its closed ring structure. Therefore, the target aromatic polysulfone can be suitably obtained without decomposition under polymerization conditions using various aprotic polar solvents, i.e., at various polymerization temperatures.

[0046] <Heat-Resistant Film> The aromatic polysulfone described above can be suitably used as a material for a molded article that requires heat resistance. For example, the aromatic polysulfone described above can be suitably used as a material for a film that requires heat resistance (heat-resistant film). The heat-resistant film of this embodiment contains the aromatic polysulfone described above having the repeating unit S1.

[0047] In the present disclosure, the term "heat-resistant film" refers to a film that has high dimensional stability at high temperatures (for example, 150°C).

[0048] Such a heat-resistant film has high heat resistance and tends to have transparency as described above, and is therefore suitable as a transparent film to be used in a high-temperature environment.

[0049] The transparency of the film can be confirmed by the following method.

[0050] [Transparency of Film] (Preparation of Film) A film is prepared by the method described in [Measurement of Linear Expansion Coefficient] (Preparation of Film) above.

[0051] (Transparency Evaluation) When 40 pt black characters are printed on copy paper and a film is placed over the printed characters, if the printed characters are legible they are judged as "transparent" and if they are unreadable they are judged as "opaque".

[0052] Other molded articles include, for example, electrical and electronic components such as connectors, sockets, IC sockets, burn-in sockets, relay parts, coil bobbins, optical pickups, oscillators, printed wiring boards, circuit boards, semiconductor packages, and computer-related parts; semiconductor manufacturing process-related parts such as IC trays and wafer carriers; household electrical appliance parts such as VTRs, televisions, irons, air conditioners, stereos, vacuum cleaners, refrigerators, rice cookers, and lighting fixtures; lighting fixture parts such as lamp reflectors and lamp holders; audio product parts such as compact discs, laser discs (registered trademark), and speakers; ferrules for optical cables, telephone parts, facsimile parts, and communication device parts such as modems; separation claws or heater holders. copier or printer related parts; mechanical parts such as impellers, fan gears, gears, bearings, or motor parts or cases; automotive parts such as automotive mechanism parts, engine parts, engine room parts, electrical parts, or interior parts; cooking utensils such as microwave cooking pots or heat-resistant tableware; heat insulating or soundproofing materials such as flooring or wall materials, support materials such as beams or pillars, building materials such as roofing materials, or civil engineering and construction materials; parts for aircraft, spacecraft, or space equipment; radiation facility components such as nuclear reactors; marine facility components, cleaning jigs, optical equipment parts, valves, pipes, nozzles, filters, membranes, medical equipment parts or medical materials, sensor parts, sanitary fixtures, sporting goods, leisure goods, or cable ties.

[0053] The molded article can be obtained by mixing aromatic polysulfone with known additives such as fillers and stabilizers, or other resin materials as needed, and melt-molding the mixture. Examples of melt-molding methods include injection molding, blow molding, vacuum molding, and press molding, with injection molding being preferred.

[0054] The aromatic polysulfone having the above-mentioned constitution is an aromatic polysulfone that can be molded into a molded article having a small linear expansion coefficient and excellent dimensional stability.

[0055] Furthermore, the heat-resistant film having the above-described structure exhibits excellent dimensional stability in a high-temperature environment.

[0056] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to these examples. The combinations and the like shown in the above examples are merely examples, and various modifications can be made based on design requirements and the like within the scope of the present disclosure.

[0057] The present disclosure will be described below with reference to examples, but the present disclosure is not limited to these examples.

[0058] In the present examples, physical properties were measured according to the following descriptions.

[0059] [Measurement of Reduced Viscosity] The reduced viscosity of the aromatic polysulfone was measured according to the description in [Measurement of Reduced Viscosity] above.

[0060] [Measurement of Glass Transition Temperature] The glass transition temperature of the aromatic polysulfone was measured according to the above-mentioned [Measurement of Glass Transition Temperature] using a differential scanning calorimeter (Shimadzu Corporation, DSC-50).

[0061] [Measurement of Linear Expansion Coefficient] The linear expansion coefficient of the aromatic polysulfone was measured according to the above-mentioned [Measurement of Linear Expansion Coefficient] using a thermomechanical analyzer (TMA, manufactured by Seiko Electronics Co., Ltd.).

[0062] [Film Transparency] The transparency of the heat-resistant film containing aromatic polysulfone was judged according to the description in [Film Transparency] above.

[0063] In the examples and comparative examples, the following monomers were used: Monomer L: 4,4'-dichlorodiphenyl sulfone Monomer M: 4,4'-difluorodiphenyl sulfone Monomer N: 4,4'-dihydroxydiphenyl sulfone Monomer O: a compound represented by the following formula (O) Monomer P: a compound represented by the following formula (P):

[0064] Example 1 In a polymerization vessel equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser with a receiver attached to its tip, 64.76 g of Monomer L, 49.56 g of Monomer N, 8.02 g of Monomer O, and 109.01 g of diphenyl sulfone as a polymerization solvent were charged, and the temperature was raised to 180° C. while circulating nitrogen gas through the system. To the obtained solution, 31.93 g of potassium carbonate was added, and the temperature was gradually raised to 290° C., and the reaction was carried out at 290° C. for an additional 3 hours.

[0065] The resulting reaction solution was then cooled to room temperature to solidify and finely pulverized. The resulting powder was washed several times, each time with warm water followed by a mixed solvent of acetone and methanol, and then heated and dried at 150°C to obtain a white powder of aromatic polysulfone of Example 1. The content of repeating units S1 relative to all repeating units of the aromatic polysulfone of Example 1 was 5 mol%.

[0066] [Example 2] An aromatic polysulfone was obtained in the same manner as in Example 1, except that the charged amounts were changed to 44.05 g of Monomer N, 16.03 g of Monomer O, and 112.39 g of diphenyl sulfone. The content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone in Example 2 was 10 mol%.

[0067] [Example 3] An aromatic polysulfone was obtained in the same manner as in Example 1, except that the charged amounts were changed to 27.53 g of Monomer N, 40.08 g of Monomer O, and 122.55 g of diphenyl sulfone. The content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone of Example 3 was 25 mol%.

[0068] [Example 4] An aromatic polysulfone was obtained in the same manner as in Example 1, except that the charged amounts were changed to 16.52 g of Monomer N, 56.12 g of Monomer O, and 129.32 g of diphenyl sulfone. The content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone of Example 4 was 35 mol%.

[0069] [Example 5] An aromatic polysulfone was obtained in the same manner as in Example 1, except that the amounts charged were changed to 0 g of Monomer N, 80.17 g of Monomer O, and 139.48 g of diphenyl sulfone. The content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone in Example 1 was 50 mol%.

[0070] [Comparative Example 1] Except for changing the charged amounts to 55.06 g of Monomer N, 0 g of Monomer O, and 105.62 g of diphenyl sulfone, an aromatic polysulfone was obtained in the same manner as in Example 1. The content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone of Comparative Example 1 was 0 mol%.

[0071] Comparative Example 2 In a polymerization vessel equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser with a receiver attached to its tip, 25.43 g of Monomer M, 35.04 g of Monomer P, and 354.50 g of diphenyl sulfone as a polymerization solvent were charged, and the temperature was raised to 180° C. while circulating nitrogen gas through the system. To the resulting solution, 14.37 g of potassium carbonate was added, and the temperature was gradually raised to 230° C., and the reaction was continued at 230° C. for an additional 12 hours.

[0072] The resulting reaction solution was then treated in the same manner as in Example 1 to obtain a white powder of aromatic polysulfone.

[0073] The results are shown in Table 1 below.

[0074]

[0075] As a result of the evaluation, it was confirmed that the aromatic polysulfones of Examples 1 to 5 and Comparative Examples 1 and 2 all had a reduced viscosity of 0.4 or more, and had similar molecular weights.

[0076] Moreover, the films obtained from the aromatic polysulfones of Examples 1 to 5 and Comparative Examples 1 and 2 were all transparent.

[0077] It was confirmed that the aromatic polysulfones of Examples 1 to 5, compared with Comparative Example 1 which does not contain the repeating unit S1, have an increased glass transition temperature and a decreased linear expansion coefficient as the repeating unit S1 increases.

[0078] Furthermore, when the aromatic polysulfone of Example 5 was compared with the aromatic polysulfone of Comparative Example 2, which used the monomer P having no spiro structure, it was confirmed that the aromatic polysulfone of Example 5 had a higher glass transition temperature and a smaller linear expansion coefficient.

[0079] The above results confirm that the present disclosure is useful.

Claims

1. An aromatic polysulfone comprising a repeating unit S1 represented by the following formula (S1) and a repeating unit S2 represented by the following formula (S2): (In formula (S1), R １ and R ２ each independently represents a hydrogen atom or an alkyl group. (In formula (S2), R ５ and R ６ each independently represents a halogen atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; m and n each independently represent an integer of 0 to 4; R ５ or R ６ If there are multiple, they may be the same or different) 2. An aromatic polysulfone in which the content of the repeating unit S1 relative to all repeating units of the aromatic polysulfone is 5 mol % or more.

3. A heat-resistant film comprising the aromatic polysulfone according to claim 1 or 2.

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