Aromatic polysulfone, production method of aromatic polysulfone, resin composition and prepreg

Abstract

To provide an aromatic polysulfone having enhanced solubility to an epoxy resin.SOLUTION: An aromatic polysulfone has a repeating unit expressed by a formula (1) and a repeating unit expressed by a formula (2). Based on a total number 100% of the repeating units composing the aromatic polysulfone, the number of the repeating units expressed by the formula (2) is 55% or more. In the formula (1), R1 and R2 independently denote an alkyl group. In the formula (2), R3 and R4 independently denote a halogen atom, a phenyl group, a 1-6C alkyl group or a 2-10C alkenyl group, and m and n independently denote an integer of 0-4. If there are a plurality of R3 or R4, they may be the same or different.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an aromatic polysulfone, a method for producing an aromatic polysulfone, a resin composition, and a prepreg. [Background technology]

[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 an aromatic polysulfone capable of exhibiting a high glass transition temperature (Tg), a prepreg using the aromatic polysulfone and a liquid epoxy resin, and a method for producing the prepreg. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-141427 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have found that aromatic polysulfones having repeating units derived from bisphenols having a fluorene skeleton tend to exhibit a high glass transition temperature (Tg). However, when this aromatic polysulfone having an improved glass transition temperature is used in the production of a prepreg, there is a problem in that it has poor solubility in an epoxy resin.

[0005] Therefore, the present invention has been made to solve the above problems, and aims to provide an aromatic polysulfone having a repeating unit derived from a bisphenol having a fluorene skeleton, the aromatic polysulfone having enhanced solubility in an epoxy resin. Another object of the present invention is to provide a resin composition containing the aromatic polysulfone and an epoxy resin. Another object of the present invention is to provide a prepreg containing the resin composition and reinforcing fibers. [Means for solving the problem]

[0006] Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result have found that an aromatic polysulfone having a specific structural repeating unit represented by formula (1) described below and a predetermined ratio of a repeating unit represented by formula (2) described below has excellent solubility with epoxy resins, thereby completing the present invention. That is, the present invention has the following aspects.

[0007] <1> An aromatic polysulfone having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): An aromatic polysulfone, in which the number of repeating units represented by the formula (2) is 55% or more relative to 100% of the total number of all repeating units constituting the aromatic polysulfone.

[0008] [ka] [In formula (1), R 1 and R 2 each independently represents an alkyl group.

[0009] [ka] [In formula (2), R 3 and R 4 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, and each of m and n independently represents an integer of 0 to 4.3 or R 4 When there are multiple, they may be the same or different.

[0010] <2> R 1 and the above R 2 is a methyl group, <1> The aromatic polysulfone according to claim 1. <3> The amount of hydroxyl groups and / or salts thereof per 1 g of the aromatic polysulfone is less than 70 μmol / g. <1> or the above <2> The aromatic polysulfone according to claim 1. <4> The weight average molecular weight is 30,000 or more and 70,000 or less. <1> ~ <3> 1. The aromatic polysulfone according to any one of claims 1 to 9.

[0011] <5> The method includes a polymerization step of polymerizing a dihydroxy compound and a dihalogeno compound to obtain an aromatic polysulfone, The dihydroxy compound includes a compound represented by the following formula (1a) and a compound represented by the following formula (2a): The method for producing an aromatic polysulfone, wherein the dihalogeno compound contains a compound represented by the following formula (2b):

[0012] [ka] [In formula (1a), R 11 and R 12 each independently represents an alkyl group.

[0013] [ka] [In formula (2a), R 13 and R 14 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, and p and q each independently represent an integer of 0 to 4. 13 or R 14 When there are multiple, they may be the same or different.

[0014] [ka] [In formula (2b), X 1 and X 2 Each of X independently represents a halogen atom. 1 and X 2 may be the same or different. 15 and R 16 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, and r and s each independently represent an integer of 0 to 4. 15 or R 16 When there are multiple, they may be the same or different.

[0015] <6> In the polymerization step, The dihydroxy compound includes dihydroxydiphenyl sulfone and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene; The dihalogeno compound includes a dihalogenodiphenyl sulfone. <5> 2. A method for producing an aromatic polysulfone according to claim 1 .

[0016] <7> In the polymerization step, The molar ratio of the dihydroxy compound to the dihalogeno compound satisfies the condition of the following formula (II): <5> or the above <6> 2. A method for producing an aromatic polysulfone according to claim 1 . The dihydroxy compound / the dihalogeno compound≦1 Formula (II)

[0017] <8> The above <1> ~ <4> 2. A resin composition comprising the aromatic polysulfone according to claim 1 and an epoxy resin. <9> The said further comprising a curing agent. <8> The resin composition according to claim 1.

[0018] <10> The above <9> A prepreg comprising the resin composition according to claim 1 and reinforcing fibers. <11> The reinforcing fibers are carbon fibers. <10> The prepreg according to claim 1. Effect of the Invention

[0019] According to the present invention, it is possible to provide an aromatic polysulfone having a repeating unit derived from a bisphenol having a fluorene skeleton, the aromatic polysulfone having enhanced solubility in an epoxy resin. The present invention also provides a resin composition comprising the aromatic polysulfone and an epoxy resin, and a prepreg comprising the resin composition and reinforcing fibers. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the aromatic polysulfone, the method for producing the aromatic polysulfone, the resin composition, and the prepreg of the present invention will be described.

[0021] <Aromatic polysulfone> In this specification, "aromatic polysulfone" refers to a resin having a repeating unit containing a divalent aromatic group (a residue obtained by removing two hydrogen atoms bonded to an aromatic ring from an aromatic compound), an ether bond (-O-), and a sulfonyl group (-SO2-). The aromatic polysulfone of the embodiment is an aromatic polysulfone having a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as "repeating unit (1)") and a repeating unit represented by the following formula (2) (hereinafter sometimes referred to as "repeating unit (2)"), in which the number of the repeating units (2) is 55% or more relative to the total number of all repeating units constituting the aromatic polysulfone (100%).

[0022] [ka] [In formula (1), R 1 and R 2 each independently represents an alkyl group.

[0023] Repeating unit (1) In the formula (1), R 1 and R 2Examples of the alkyl group in the formula (I) include alkyl groups having 1 to 6 carbon atoms, and preferred examples thereof 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, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, an n-decyl group, etc. The alkyl group may be linear or branched.

[0024] From the viewpoint of improving the solubility of aromatic polysulfone in epoxy resin, R 1 and R 2 are each independently preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms; R 1 and R 2 More preferably, each of R is a methyl group. 1 and R 2 It is particularly preferable that each of these is a methyl group.

[0025] [ka] [In formula (2), R 3 and R 4 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, and each of m and n independently represents an integer of 0 to 4. 3 or R 4 When there are multiple, they may be the same or different.

[0026] Repeating unit (2) In the formula (2), R 3 and R 4 As the alkyl group in the formula (1), R 1 and R 2 Examples of the alkyl group include those exemplified in the above. In the formula (2), R 3 and R 4 As the alkenyl group in the formula (1), R 1 and R 2In the alkyl groups exemplified above, one in which a single bond (CC) between any two carbon atoms is replaced with a double bond (C=C), and the position of the double bond is not limited.

[0027] In the formula (2), m and n are each preferably 0.

[0028] In the aromatic polysulfone, the number of repeating units (2) is 55% or more, preferably 60% or more, and more preferably 65% ​​or more, based on 100% of the total number of all repeating units constituting the aromatic polysulfone. At or above the lower limit above, the aromatic polysulfone having the repeating unit (2) has improved solubility in epoxy resins, a higher thermal decomposition temperature, and excellent heat resistance.

[0029] The aromatic polysulfone preferably contains, for example, 55% or more and 98% or less of the repeating unit (2), more preferably 60% or more and 95% or less, and even more preferably 65% ​​or more and 95% or less, based on 100% of the total number of all repeating units constituting the aromatic polysulfone.

[0030] The aromatic polysulfone of the present embodiment may have, for example, 55% or more and 98% or less of repeating units (2) and 2% or more and 45% or less of repeating units (1), or 60% or more and 95% or less of repeating units (2) and 5% or more and 40% or less of repeating units (1), relative to 100% in total number of all repeating units constituting the aromatic polysulfone.

[0031] In addition to the repeating unit (1) and the repeating unit (2), the aromatic polysulfone may further have one or more other repeating units such as a repeating unit represented by the following formula (3) (hereinafter sometimes referred to as "repeating unit (3)") or a repeating unit represented by the following formula (4) (hereinafter sometimes referred to as "repeating unit (4)").

[0032] (3)-Ph 3 -R-Ph 4 -O- [In the formula, Ph 3 and Ph 4 each independently represents a phenylene group. A hydrogen atom in the phenylene group may be independently substituted with an alkyl group, an aryl group, a halogen atom, a sulfo group, a nitro group, an amino group, a carboxyl group, or a hydroxyl group. R represents an alkylidene group, an oxygen atom, or a sulfur atom.

[0033] (4)-(Ph 5 ) t -O- [In the formula, Ph 5 represents a phenylene group. Each hydrogen atom in the phenylene group may be independently substituted with an alkyl group, an aryl group, a halogen atom, a sulfo group, a nitro group, an amino group, a carboxyl group, or a hydroxyl group. t represents an integer of 1 to 3. When t is 2 or more, a plurality of Ph 5 may be the same or different.

[0034] Ph 3 ~Ph 5 The phenylene group represented by any one of the following formulas may be a p-phenylene group, an m-phenylene group, or an o-phenylene group, but is preferably a p-phenylene group.

[0035] The number of carbon atoms in the alkyl group which may substitute a hydrogen atom in the phenylene group in the formulas (3) and (4) is preferably 1 to 10. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a s-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, and an n-decyl group.

[0036] The number of carbon atoms in the aryl group which may replace a hydrogen atom in the phenylene group in the formulas (3) and (4) is preferably 6 to 20. Specific examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0037] Examples of the halogen atom which may replace a hydrogen atom in the phenylene group in the formulas (3) and (4) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0038] When a hydrogen atom in the phenylene group of the repeating units (3) to (4) is substituted with these groups, the number of such groups is preferably 2 or less, more preferably 1, independently for each phenylene group. Among the above, it is preferred that the hydrogen atoms in the phenylene groups of the repeating units (3) and (4) are not substituted.

[0039] The number of carbon atoms in the alkylidene group represented by R is preferably 1 to 5. Specific examples include a methylene group, an ethylidene group, an isopropylidene group, and a 1-butylidene group.

[0040] The aromatic polysulfone of the embodiment may have two or more repeating units (3) and (4) independently in addition to the repeating unit (1) and the repeating unit (2). Among them, the aromatic polysulfone having only the repeating unit (1) and the repeating unit (2) as the repeating unit is more preferable.

[0041] The aromatic polysulfone of the embodiment may have a hydroxyl group and / or a salt thereof in its molecule. The salt of a hydroxyl group may be composed of an oxyanion group formed by dissociating a proton from a hydroxyl group, and a counter cation. Examples of the counter cation include alkali metal ions such as lithium ion, sodium ion, and potassium ion; alkaline earth metal ions such as magnesium ion and calcium ion; and ammonium ions and quaternary ammonium ions formed by protonating ammonia or primary to tertiary amines. When the counter cation is a polyvalent cation such as an alkaline earth metal ion, the counter anion may be composed of a plurality of oxyanion groups, or may be composed of an oxyanion group and another anion such as a chloride ion or hydroxide ion.

[0042] The hydroxyl group and / or salt thereof may be located at a terminal of the main chain of the aromatic polysulfone, i.e., the aromatic polysulfone may have at least one terminal hydroxyl group and / or salt thereof at the terminal of the main chain of the aromatic polysulfone.

[0043] In the aromatic polysulfone of the embodiment, the amount of hydroxyl groups and / or salts thereof per 1 g of the aromatic polysulfone is preferably less than 70 μmol / g, more preferably 65 μmol / g or less, and even more preferably less than 65 μmol / g. When the aromatic polysulfone contains a hydroxyl group and / or a salt thereof in an amount less than the above upper limit, the cured product of a resin composition containing the aromatic polysulfone and an epoxy resin can exhibit superior heat resistance.

[0044] The amount of hydroxyl groups and / or salts thereof per 1 g of the aromatic polysulfone may be 10 μmol / g or more, 15 μmol / g or more, or 20 μmol / g or more. The amount of hydroxyl groups and / or salts thereof per 1 g of the aromatic polysulfone may be in the range of 10 μmol / g or more and less than 70 μmol / g, 15 μmol / g or more and less than 65 μmol / g, or 20 μmol / g or more and less than 65 μmol / g.

[0045] The amount of hydroxyl groups and / or salts thereof per gram of aromatic polysulfone is determined by the following measurement method. The amount of hydroxyl groups and / or salts thereof in aromatic polysulfone means the total content of the hydroxyl groups and the salts of the hydroxyl groups.

[0046] <Measurement of the total amount of hydroxyl groups and their salts in aromatic polysulfone (μmol / g)> A specified amount of aromatic polysulfone is dissolved in dimethylformamide, and an excess amount of p-toluenesulfonic acid is added. Next, using a potentiometric titrator, titrate with 0.05 mol / L potassium hydroxide / toluene-methanol solution to neutralize the remaining p-toluenesulfonic acid, and then neutralize the hydroxyl groups. The amount (mol) of potassium methoxide required to neutralize the hydroxyl groups is divided by the specified amount (g) of aromatic polysulfone to determine the total amount of hydroxyl groups and their salts.

[0047] The weight average molecular weight (Mw) of the aromatic polysulfone of the embodiment is preferably 30,000 or more and 70,000 or less, may be 31,000 or more and 68,000 or less, or may be 32,000 or more and 66,000 or less. When an aromatic polysulfone has a weight average molecular weight within the numerical range, a cured product of a resin composition containing the aromatic polysulfone and an epoxy resin can exhibit superior heat resistance.

[0048] The polydispersity (Mw / Mn) of the aromatic polysulfone is not particularly limited, but may be 1.0 to 4.0, 1.0 to 3.0, or 1.0 to 2.5.

[0049] The Mw and Mn of the aromatic polysulfone can be measured by the following method.

[0050] <Measurement of Mw and Mn of aromatic polysulfone, and calculation of Mw / Mn> The weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw / Mn) of aromatic polysulfone are determined by GPC measurement under the following [measurement conditions]. Note that Mn and Mw are each measured twice, and the average values ​​are calculated to be Mn and Mw, respectively, and the average value of Mw / Mn is calculated.

[0051] [Measurement conditions] Sample: 0.002 g of aromatic polysulfone was mixed with 1 mL of N,N-dimethylformamide solution containing 10 mM lithium bromide. Sample injection volume: 100 μL Column (stationary phase): Two Tosoh Corporation "TSKgel GMHHR-H" (7.8 mmφ × 300 mm) connected in series. Column temperature: 40℃ Eluent (mobile phase): N,N-dimethylformamide containing 10 mM lithium bromide Eluent flow rate: 0.8mL / min Detector: Differential refractometer (RI) + light scattering photometer (LS) dn / dc: Calculated from the peak area, injection concentration, and dn / dc (0.159) of a standard polystyrene with a known dn / dc value, and the peak area and injection concentration of the sample. Molecular weight calculation method: Absolute molecular weight is calculated using a light scattering photometer (LS).

[0052] The aromatic polysulfone of the embodiment has the repeating unit (1), and therefore can exhibit a high glass transition temperature (Tg) and is excellent in heat resistance.

[0053] The Tg of the aromatic polysulfone may be 230° C. or more, 235° C. or more, or 240° C. or more. The upper limit of the Tg of the aromatic polysulfone is not particularly limited, and may be, for example, 260° C. or less, 255° C. or less, or 253° C. or less. The upper and lower limits of the glass transition temperature can be combined in any desired manner, and the Tg of the aromatic polysulfone may be, for example, 230°C or more and 260°C or less, 235°C or more and 255°C or less, or 240°C or more and 253°C or less.

[0054] The glass transition temperature (Tg) of the aromatic polysulfone can be measured by the following method.

[0055] <Measurement of glass transition temperature (Tg) of aromatic polysulfone> Using a differential scanning calorimeter (e.g., DSC-50 manufactured by Shimadzu Corporation), the glass transition temperature of the aromatic polysulfone is calculated according to a method in accordance with JIS-K 7121. Approximately 10 mg of aromatic polysulfone is weighed out, heated to 400°C at a heating rate of 10°C / min, cooled to 50°C, and then heated again 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 in the second heating.

[0056] Among the above, a preferred aromatic polysulfone according to the embodiment is an aromatic polysulfone having a repeating unit (1) and a repeating unit (2), in which R 1 and R 2 is a methyl group, in the repeating unit (2), m and n are 0, the number of repeating units (2) is 55% or more with respect to 100% of the total number of all repeating units constituting the aromatic polysulfone, and more preferably, the amount of hydroxyl groups and / or salts thereof per 1 g of the aromatic polysulfone is less than 70 μmol / g or the weight average molecular weight (Mw) is 30,000 or more and 70,000 or less.

[0057] <Method for producing aromatic polysulfone> The method for producing an aromatic polysulfone of the present embodiment includes a polymerization step of polymerizing a dihydroxy compound and a dihalogeno compound to obtain an aromatic polysulfone, in which the dihydroxy compound includes a compound represented by the following formula (1a) and a compound represented by the following formula (2a), and the dihalogeno compound includes a compound represented by the following formula (2b).

[0058] [ka] [In formula (1a), R 11 and R 12 each independently represents an alkyl group.

[0059] In the formula (1a), R 11 is the R in the formula (1). 1 is synonymous with R 12 is the R in the formula (1). 2 is synonymous with. An example of the dihydroxy compound represented by the formula (1a) is 9,9-bis(4-hydroxy-3-methylphenyl)fluorene.

[0060] [ka] [In formula (2a), R 13 and R 14 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, and p and q each independently represent an integer of 0 to 4. 13 or R 14 When there are a plurality of p and q, they may be the same or different. Each of p and q is preferably 0.

[0061] In the above formula (2a), R 13 is the R in the formula (2). 3 is synonymous with R 14 is the R in the formula (2). 4 is synonymous with. An example of the dihydroxy compound represented by the formula (2a) is dihydroxydiphenylsulfone.

[0062] [ka] [In formula (2b), X 1 and X 2 Each of X independently represents a halogen atom. 1 and X 2 may be the same or different. 15 and R 16 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, and r and s each independently represent an integer of 0 to 4. 15 or R 16 When there are a plurality of r and s, they may be the same or different. Each of r and s is preferably 0.]

[0063] In the formula (2b), X 1 and X 2 Examples of the halogen atom in include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is preferable. R 15 is the R in the formula (2). 3 is synonymous with R 16 is the R in the formula (2). 4 is synonymous with. An example of the dihalogeno compound represented by the formula (2b) is dihalogenodiphenylsulfone.

[0064] In the method for producing an aromatic polysulfone according to the embodiment, in the polymerization step, the dihydroxy compound preferably includes dihydroxydiphenylsulfone and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, and the dihalogeno compound preferably includes dihalogenodiphenylsulfone.

[0065] A preferred embodiment of a method for producing an aromatic polysulfone includes a polymerization step of polymerizing a dihydroxy compound and a dihalogeno compound to obtain an aromatic polysulfone, wherein the dihydroxy compound includes a compound represented by formula (1a) and a compound represented by formula (2a), the dihalogeno compound includes a compound represented by formula (2b), and the total amount of the compound represented by formula (1a), the compound represented by formula (2a), and the compound represented by formula (2b) may be 90 mol% or more relative to the total monomers (100 mol%) used in the polymerization of the aromatic polysulfone.

[0066] A particularly preferred embodiment of the method for producing an aromatic polysulfone may be a method including a polymerization step of polymerizing a dihydroxy compound and a dihalogeno compound to obtain an aromatic polysulfone, in which the dihydroxy compound is composed of a compound represented by the formula (1a) and a compound represented by the formula (2a), and the dihalogeno compound is composed of a compound represented by the formula (2b).

[0067] In the method for producing an aromatic polysulfone according to the embodiment, it is preferable that in the polymerization step, the molar ratio of the dihydroxy compound to the dihalogeno compound satisfies the condition of the following formula (II).

[0068] The dihydroxy compound / the dihalogeno compound≦1 Formula (II)

[0069] By satisfying the condition of the formula (II) above, i.e., by making the value of the molar ratio 1 or less, it is possible to easily produce an aromatic polysulfone in which the number of repeating units represented by the formula (2) above is 55% or more relative to 100% of the total number of all repeating units constituting the aromatic polysulfone.

[0070] As shown in formula (II), the value of the dihydroxy compound / the dihalogeno compound is 1 or less, may be 0.95 or more and 1 or less, or may be 0.96 or more and 1 or less.

[0071] With respect to the dihydroxy compounds in the polymerization step, the ratio of the compound represented by formula (1a) to the total amount (100 mol%) of the dihydroxy compounds may be 80 mol% or less, 75 mol% or less, 70 mol% or less, or 65 mol% or less. In particular, when the proportion of the compound represented by formula (1a) relative to the total amount (100 mol%) of the dihydroxy compound is less than 90 mol%, it is possible to easily produce an aromatic polysulfone having 55% or more of the repeating unit (2) relative to the total number (100%) of all repeating units constituting the aromatic polysulfone.

[0072] The ratio of the compound represented by formula (1a) to the total amount (100 mol%) of the dihydroxy compounds may be, for example, 5 mol% or more and 80 mol% or less, 20 mol% or more and 75 mol% or less, 30 mol% or more and 70 mol% or less, or 50 mol% or more and 65 mol% or less.

[0073] In this production method, the condition of formula (II) is satisfied, i.e., the condition of the dihydroxy compound / the dihalogeno compound≦1, and further, the ratio of the compound represented by formula (1a) to the total amount (100 mol%) of the dihydroxy compounds is within the above range, so that it is possible to more easily produce an aromatic polysulfone having 55% or more of the repeating unit (2) relative to the total number (100 mol%) of all repeating units constituting the aromatic polysulfone.

[0074] Furthermore, an aromatic polysulfone having the repeating unit (3) exemplified above in addition to the repeating unit (1) and the repeating unit (2) can be produced by containing, as dihydroxy compounds, the compound represented by the formula (1a) and the compound represented by the formula (2a), as dihalogeno compounds, and a compound represented by the formula (2b) below as a dihydroxy compound.

[0075] (5)HO-Ph 3 -R-Ph 4 -OH [In the formula, Ph 3 , Ph 4 and R has the same meaning as above.]

[0076] Furthermore, an aromatic polysulfone having the repeating unit (4) exemplified above in addition to the repeating unit (1) and the repeating unit (2) can be produced by including, as dihydroxy compounds, the compound represented by the formula (1a) and the compound represented by the formula (2a), as dihalogeno compounds, the compound represented by the formula (2b), and as dihydroxy compounds, the compound represented by the following formula (6):

[0077] (6)HO-(Ph 5 ) t -OH [In the formula, Ph 5 and t are as defined above.]

[0078] The OH groups in the above formulae (1a), (2a) and (5) to (6) may correspond to hydroxyl groups and salts thereof which may be located at the main chain terminals of the aromatic polysulfone.

[0079] The polycondensation of aromatic polysulfone is preferably carried out in a solvent using an alkali metal salt of carbonate. The alkali metal salt of carbonate may be a carbonate, which is a normal salt, a bicarbonate (hydrogen carbonate), which is an acidic salt, or a mixture of the two. As the carbonate, sodium carbonate or potassium carbonate is preferably used, and as the hydrogen carbonate, sodium bicarbonate or potassium bicarbonate is preferably used.

[0080] As the solvent for polycondensation, an organic polar solvent is preferably used, specific examples of which include dimethyl sulfoxide, 1-methyl-2-pyrrolidone, sulfolane (1,1-dioxothiane), 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, and diphenyl sulfone.

[0081] ≪Resin composition≫ The resin composition of the embodiment contains an aromatic polysulfone and an epoxy resin. The aromatic polysulfone in the resin composition may be, for example, the same aromatic polysulfone as in the above embodiment. As an example, the resin composition of the embodiment may be <1> ~ <4> and an epoxy resin.

[0082] The content of the aromatic polysulfone in the resin composition of the embodiment is preferably 1 to 70 parts by mass, more preferably 2 to 50 parts by mass, even more preferably 4 to 30 parts by mass, and particularly preferably 5 to 20 parts by mass, relative to 100 parts by mass of the total of the epoxy resin and the aromatic polysulfone. Alternatively, the content of aromatic polysulfone in the resin composition of the embodiment is preferably 2 to 25 mass%, more preferably 5 to 20 mass%, and even more preferably 10 to 15 mass%, relative to 100 mass% of the total mass of the resin composition.

[0083] <Epoxy resin> In this specification, the epoxy resin means a compound having at least one epoxy group in the molecule. Examples of the epoxy resin include glycidyl ether type epoxy compounds obtained by reacting polyhydric phenols such as bisphenol A, bisphenol F, bisphenol S, hexahydrobisphenol A, tetramethylbisphenol A, resorcinol, cresol novolak, tetrabromobisphenol A, trihydroxybiphenyl, bisresorcinol, bisphenol hexafluoroacetone, tetramethylbisphenol F, bixylenol, and dihydroxynaphthalene with epichlorohydrin; alicyclic glycidyl ether type epoxy compounds obtained by hydrogenating the glycidyl ether type epoxy compounds; polyglycidyl ether type epoxy compounds obtained by reacting aliphatic polyhydric alcohols such as glycerin, neopentyl glycol, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, polyethylene glycol, and polypropylene glycol with epichlorohydrin; and glycidyl ester type epoxy compounds obtained by reacting hydroxycarboxylic acids such as p-oxybenzoic acid and β-oxynaphthoic acid with epichlorohydrin. Examples of the epoxy compounds include polyglycidyl ester type epoxy compounds derived from polycarboxylic acids such as phthalic acid, methylphthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, endomethylenetetrahydrophthalic acid, endomethylenehexahydrophthalic acid, trimellitic acid, and polymerized fatty acids; glycidyl aminoglycidyl ether type epoxy compounds derived from aminophenols, aminoalkylphenols, and the like; glycidyl aminoglycidyl ester type epoxy compounds derived from aminobenzoic acid; and flexible epoxy resins whose skeletons are polyether, polyurethane, polycarbonate, polyester, polyacrylic, silicone, and the like. The epoxy resin may be used alone or in combination of two or more kinds.

[0084] The number of epoxy groups per molecule of the epoxy resin is not particularly limited, and the epoxy resin may be a compound having two epoxy groups in the molecule (bifunctional epoxy resin), or a compound having three or more epoxy groups in the molecule (polyfunctional epoxy resin).

[0085] The epoxy resin is preferably a liquid epoxy resin. A liquid epoxy resin refers to an epoxy resin that is in a liquid state at 50° C. (at normal pressure).

[0086] The content of the epoxy resin in the resin composition of the embodiment is preferably 30 to 99 parts by mass, more preferably 50 to 98 parts by mass, even more preferably 70 to 96 parts by mass, and particularly preferably 80 to 95 parts by mass, relative to 100 parts by mass of the total of the epoxy resin and the aromatic polysulfone. Alternatively, the content of the epoxy resin in the resin composition of the embodiment is more preferably 40 to 75 mass%, even more preferably 50 to 70 mass%, and particularly preferably 55 to 65 mass%, relative to 100 mass% of the total mass of the resin composition.

[0087] <Hardening agent> The resin composition of the present embodiment may further contain a curing agent. The curing agent according to the present embodiment is not particularly limited as long as it can react with the epoxy resin, and includes compounds that are usually used as curing agents for epoxy resins, and amine-based curing agents are preferably used. Examples of such curing agents include tetramethylguanidine, imidazole or its derivatives, carboxylic acid hydrazides, tertiary amines, aromatic amines, aliphatic amines, dicyandiamide or its derivatives, etc. The aromatic amine is preferably diaminodiphenylmethane, bis(4-aminophenyl)sulfone or a derivative thereof. The aromatic amine may be used alone or in combination of two or more kinds.

[0088] In this specification, the term "derivative" refers to a compound in which the basic structure of the compound is not changed and a small part of the compound is replaced with another atom or atomic group.

[0089] The curing agent may be used alone or in combination of two or more kinds. The content of the curing agent in the resin composition is preferably 0.5 to 1.5 equivalents per equivalent of the epoxy group of the epoxy resin. When the content is 0.5 equivalents or more, the resin is cured well and good mechanical properties are easily exhibited. When the content is 1.5 equivalents or less, unreacted substances of the curing agent are unlikely to remain, and good mechanical properties are easily obtained. The amount of the curing agent to be added is not particularly limited, but is preferably 0.1 to 5 parts by weight per 100 parts by weight of the epoxy resin.

[0090] <Other ingredients> The resin composition of the present embodiment may contain other components that do not fall under any of the above-mentioned aromatic polysulfone, epoxy resin, and curing agent, as desired. Examples of other components include solvents, resins that do not fall under the category of aromatic polysulfone and epoxy resin, coloring components, lubricants, various surfactants, antioxidants, heat stabilizers, other various stabilizers, ultraviolet absorbers, antistatic agents, etc. The content of other components is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 0% by mass or more and less than 5% by mass, relative to the total mass of the resin composition of this embodiment.

[0091] ·solvent The resin composition of the present embodiment may further contain a solvent. However, from the viewpoint of reducing the amount of the solvent remaining in a cured product obtained by curing the resin composition containing the aromatic polysulfone of the embodiment, it is preferable that the amount of the solvent contained in the resin composition is small.

[0092] The solvent may be an organic solvent, and the organic solvent may be a polar solvent or an aprotic polar solvent.

[0093] The solvent used is preferably one that has the effect of improving the affinity of the aromatic polysulfone with the epoxy resin. Examples of the solvent include aprotic polar solvents such as N-ethylpyrrolidone, N,N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, and sulfolane.

[0094] The resin composition of the present embodiment preferably has a solvent content of 0 to 5 parts by mass, more preferably 0 to 1 part by mass, relative to 100 parts by mass of the epoxy resin and the aromatic polysulfone in total, and further preferably contains substantially no solvent. The content of the solvent may be 0 to 5 mass %, 0 to 1 mass %, or 0 to 0.1 mass %, relative to the total mass of the resin composition of the embodiment, and it is preferable that the resin composition contains substantially no solvent.

[0095] Other resins The resin composition of the present embodiment may further contain another resin that does not fall into the category of either aromatic polysulfone or epoxy resin. Examples of other resins include polyamide, polyester, polyphenylene sulfide, polycarbonate, polyphenylene ether, aromatic polyketone, polyetherimide, phenolic resin, polyimide resin, and modified products thereof. The content of the other resin is preferably 0 to 10 mass %, more preferably 0 to 5 mass %, and even more preferably 0 to 1 part by mass, relative to the total mass of the resin composition, and the resin composition may not substantially contain other resins.

[0096] According to the resin composition of the embodiment described above, it is possible to provide various molded articles having improved glass transition temperatures (tan δ) measured by dynamic mechanical analysis (DMA) and excellent heat resistance.

[0097] ≪Cured product≫ The cured product of this embodiment is obtained by curing the resin composition of the above-described embodiment. For example, by heating the resin composition of the embodiment containing a curing agent to a temperature higher than 150° C. and not higher than 200° C. to cure it, a cured product of any shape and form can be easily produced.

[0098] When curing the resin composition, it is preferable to cure a composition in which the epoxy resin and the aromatic polysulfone are uniformly mixed by dissolving the aromatic polysulfone in the epoxy resin or by miscible mixing of the epoxy resin and the aromatic polysulfone.

[0099] The cured product of the present embodiment uses the resin composition of the above-mentioned embodiment, and therefore has an improved glass transition temperature (tan δ) measured by dynamic mechanical analysis (DMA) and has heat resistance.

[0100] <Prepreg> The prepreg of the present embodiment contains the above-mentioned resin composition and reinforcing fibers. The prepreg of the present embodiment may be one in which the above-mentioned resin composition is impregnated into reinforcing fibers. From the viewpoint of the strength of the prepreg, the reinforcing fiber is preferably at least one selected from the group consisting of carbon fiber, glass fiber, boron fiber, and aramid fiber, and from the viewpoints of mechanical properties and light weight, the reinforcing fiber is more preferably carbon fiber. These reinforcing fibers may be in the form of a woven or nonwoven fabric.

[0101] The method for producing the prepreg of the present embodiment is not particularly limited, and for example, the above-mentioned resin composition may be impregnated into reinforcing fibers. Methods for impregnating the reinforcing fibers with the resin composition include a wet method and a hot melt method (dry method).

[0102] The wet method is a method in which reinforcing fibers are immersed in a resin composition, then pulled out, and the solvent is evaporated from the reinforcing fibers using an oven or the like, thereby impregnating the reinforcing fibers with the resin composition.

[0103] The hot melt method is a method in which a resin composition whose viscosity has been reduced by heating is directly impregnated into reinforcing fibers. Another form of the hot melt method is a method in which a film in which the resin composition is coated on a release paper or the like is prepared, and then the film is placed on both sides or one side of the reinforcing fibers, and the reinforcing fibers are impregnated with the resin composition by heating and pressing.

[0104] After impregnating the reinforcing fibers with the resin composition in this manner, the prepreg can be produced by curing the impregnated resin composition by heating, for example, to 120 to 150° C. The impregnated resin composition may be semi-cured.

[0105] As used herein, the term "semi-cured" refers to a state in which the viscosity or hardness of a resin has increased to a level where a certain shape can be maintained, and from that state, the viscosity or hardness can be increased further.

[0106] As one embodiment of the present invention, there is provided a cured product obtained by curing the above prepreg. According to the prepreg of the present embodiment, since the resin composition of the embodiment is used, it is possible to provide a cured prepreg having an improved glass transition temperature (tan δ) measured by dynamic mechanical analysis (DMA) and good heat resistance.

[0107] As another embodiment of the present invention, there is provided a product formed by laminating a plurality of the above-mentioned prepregs. Specifically, the product formed by laminating a plurality of the above-mentioned prepregs can be obtained by stacking a plurality of the prepregs produced by the above-mentioned method and thermosetting and molding them using an autoclave or a heat press machine or the like.

[0108] The prepreg lamination pattern can be a method of laminating the prepregs with the reinforcing fibers in the same direction (0°), or a method of laminating the prepregs while shifting them at any angle. For example, when shifting by 45°, the lamination will be 0° / 45° / 90° / 135° / 180° / 225° / 270° / 315° / 360°(0°). The term "displaced at an arbitrary angle" means changing the relative angle between the fiber directions of the two layers of prepreg to be laminated. The arbitrary angle can be appropriately set depending on the application of the molded article. EXAMPLES

[0109] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0110] <Measurement of Mw and Mn of aromatic polysulfone, and calculation of Mw / Mn> The weight average molecular weight (Mw), number average molecular weight (Mn) and polydispersity (Mw / Mn) of the aromatic polysulfone were determined by GPC measurement under the following [measurement conditions]. Note that Mw and Mn were each measured twice, and the average values ​​were calculated as Mw and Mn, respectively, and the average value of Mw / Mn was calculated.

[0111] [Measurement conditions] Sample: 0.002 g of aromatic polysulfone was mixed with 1 mL of N,N-dimethylformamide solution containing 10 mM lithium bromide. Sample injection volume: 100 μL Column (stationary phase): Two Tosoh Corporation "TSKgel GMHHR-H" (7.8 mmφ × 300 mm) connected in series. Column temperature: 40℃ Eluent (mobile phase): N,N-dimethylformamide containing 10 mM lithium bromide Eluent flow rate: 0.8mL / min Detector: Differential refractometer (RI) + light scattering photometer (LS) dn / dc: Calculated from the peak area, injection concentration, and dn / dc (0.159) of a standard polystyrene with a known dn / dc value, and the peak area and injection concentration of the sample. Molecular weight calculation method: Absolute molecular weight is calculated using a light scattering photometer (LS).

[0112] <Measurement of glass transition temperature (Tg) of aromatic polysulfone> The glass transition temperature (Tg) of the aromatic polysulfone was calculated using a differential scanning calorimeter (Shimadzu DSC-50) according to the method of JIS-K7121. Approximately 10 mg of aromatic polysulfone was weighed out, heated to 400°C at a heating rate of 10°C / min, cooled to 50°C, and then heated again to 400°C at a heating rate of 10°C / min. The glass transition temperature (Tg) of the aromatic polysulfone was calculated from the DSC chart obtained from the second heating.

[0113] <Measurement of the total amount of hydroxyl groups and their salts in aromatic polysulfone (μmol / g)> A given amount of aromatic polysulfone was dissolved in dimethylformamide, and an excess amount of p-toluenesulfonic acid was added. Next, using a potentiometric titrator, the solution was titrated with 0.05 mol / L potassium hydroxide / toluene-methanol solution to neutralize the remaining p-toluenesulfonic acid, and then the hydroxyl groups were neutralized. The amount (mol) of potassium methoxide required to neutralize the hydroxyl groups was divided by the given amount (g) of aromatic polysulfone to determine the total amount of hydroxyl groups and their salts.

[0114] <Evaluation of solubility of aromatic polysulfone in epoxy resin> The properties of the epoxy resin composition obtained by the method described below were visually confirmed, and the solubility of the aromatic polysulfone in the epoxy resin was evaluated according to the following criteria. A: No significant turbidity was observed in the epoxy resin composition, and the solubility of the aromatic polysulfone in the epoxy resin was very good. B: The epoxy resin composition was slightly turbid, and the solubility of the aromatic polysulfone in the epoxy resin was somewhat poor. F: A homogeneous epoxy resin composition was not obtained, and the solubility of the aromatic polysulfone in the epoxy resin was poor. In addition, a cured product of the epoxy resin composition could not be obtained.

[0115] <Glass transition temperature (tan δ) of the cured product of the epoxy resin composition> The cured product of the epoxy resin composition obtained by the method described below was used as a measurement sample, and the glass transition temperature (°C) of the cured product was measured by dynamic mechanical analysis (DMA). Specifically, the glass transition temperature (°C) was determined from the peak top temperature of tan δ measured under the following conditions using a dynamic viscoelasticity measuring device (TA Instruments, Q800).

[0116] [Measurement conditions for tan δ] Measurement mode: Bending mode Amplitude: 20μm Frequency: 10Hz Heating rate: 5℃ / min

[0117] <Production of aromatic polysulfone> Example 1 In a polymerization tank equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser with a receiver at the tip, 220.55 g of dichlorodiphenylsulfone (DCDPS), 80.09 g of dihydroxydiphenylsulfone (DHDPS), 181.67 g of 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (BHMPF), 116.10 g of potassium carbonate, and 443 g of N-methyl-2-pyrrolidone (NMP) were mixed and reacted at 190°C for 10 hours. Next, the resulting reaction mixture was diluted with NMP and cooled to room temperature to precipitate unreacted potassium carbonate and potassium chloride produced as a by-product. The above solution was dropped into water to precipitate aromatic polysulfone, and unnecessary NMP was removed by filtration to obtain a precipitate. The resulting precipitate was carefully washed repeatedly with water and dried by heating at 150°C to obtain the aromatic polysulfone of Example 1.

[0118] Table 1 shows the molar ratios of the dihydroxy monomers (DHDPS and BHMPF) and the dichloro monomer (DCDPS) used in the polymerization of the aromatic polysulfone. Table 1 also shows the ratio (mol %) of bisphenol fluorene monomer (BHMPF) relative to the total amount (100 mol %) of dihydroxy monomers (DHDPS and BHMPF) used in the polymerization of aromatic polysulfone.

[0119] <Examples 2 and 3> In Example 1, the molar ratio of the dihydroxy monomers (DHDPS and BHMPF) and the dichloro monomer (DCDPS) used in the polymerization of the aromatic polysulfone was changed to the value shown in Table 1, and further, the ratio (mol%) of the bisphenol fluorene monomer (BHMPF) relative to the total amount (100 mol%) of the dihydroxy monomers (DHDPS and BHMPF) used in the polymerization of the aromatic polysulfone was changed to the value shown in Table 1. Except for this, the aromatic polysulfone of each Example was obtained in the same manner as in Example 1 above.

[0120] Comparative Example 1 In Example 1, dihydroxydiphenyl sulfone (DHDPS) was not used, and only bisphenol fluorene monomer (BHMPF) was used as the dihydroxy monomer used in the polymerization of aromatic polysulfone. The molar ratio of bisphenol fluorene monomer (BHMPF) to dichloro monomer (DCDPS) was changed to the value shown in Table 1. The aromatic polysulfone of Comparative Example 1 was obtained in the same manner as in Example 1.

[0121] Comparative Example 2 An aromatic polysulfone of Comparative Example 2 was obtained in the same manner as in Example 1, except that 9,9-bis(4-hydroxyphenyl)fluorene (BHPF) was used instead of 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (BHMPF) used in the polymerization of aromatic polysulfone in Example 1.

[0122] The weight average molecular weight (Mw), polydispersity (Mw / Mn), Tg, and total amount of hydroxyl groups and their salts (referred to as the hydroxyl group amount in Table 1) of the aromatic polysulfones obtained in each of the Examples and Comparative Examples are shown in Table 1.

[0123] <Production of Cured Epoxy Resin Composition> <Cured Products of Examples 1 to 3 and Comparative Examples 1 and 2> In a 500 mL separable flask, 20 g of any of the aromatic polysulfones obtained in each of the above Examples and Comparative Examples and 100 g of an epoxy resin (Sumiepoxy ELM-100, manufactured by Sumitomo Chemical) were placed and stirred at 130°C for 1 hour, then cooled to 100°C, 45 g of bis(4-aminophenyl)sulfone (manufactured by Aldrich Japan) was placed and stirred at 140°C for 1 hour to obtain an epoxy resin composition. The obtained epoxy resin composition was filled into a metal frame with a thickness of 3 mm, and then heat-cured at 180°C for 2 hours using a high-temperature hot air dryer to obtain cured products of the epoxy resin compositions of Examples 1 to 3 and Comparative Examples 1 to 2.

[0124] <Cured product of Comparative Example 3> A cured product of the epoxy resin composition of Comparative Example 3 was obtained by the same procedure as in the production of the cured product of the epoxy resin composition of Example 1 etc., except that the aromatic polysulfone was not added.

[0125] For the cured product of the epoxy resin composition obtained above, the glass transition temperature (tan δ) was measured. The value is shown in Table 1.

[0126] [Table 1]

[0127] The aromatic polysulfones of Examples 1 to 3 were superior in solubility in epoxy resin to the aromatic polysulfones of Comparative Examples 1 and 2. This indicates that aromatic polysulfones in which the number of repeating units represented by the formula (2) is 55% or more relative to the total number of all repeating units constituting the aromatic polysulfone (100%) have excellent solubility in epoxy resins.

[0128] In addition, the aromatic polysulfones of Examples 1 to 3, which used 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (BHMPF) as a monomer, had better solubility in epoxy resins than Comparative Example 2, which used 9,9-bis(4-hydroxyphenyl)fluorene (BHPF). From this, the R 1 and the above R 2 It was shown that aromatic polysulfones in which the alkyl group is an alkyl group can exhibit superior solubility in epoxy resins.

[0129] Furthermore, the cured products of the epoxy resin compositions of Examples 2 and 3 had higher tan δ temperatures than the cured product of the epoxy resin composition of Example 1, and thus had even more excellent heat resistance. This indicates that a cured product of an epoxy resin composition containing an aromatic polysulfone having an amount of hydroxyl groups and / or salts thereof measured above of less than 70 μmol, or an aromatic polysulfone having a weight average molecular weight of 30,000 or more and 70,000 or less, has superior heat resistance.

[0130] The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to each embodiment, but is limited only by the scope of the claims.

Claims

1. An aromatic polysulfone having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2): An aromatic polysulfone, wherein the number of repeating units represented by the formula (2) is 55% or more relative to 100% of the total number of all repeating units constituting the aromatic polysulfone. 【Chemistry 1】 [In formula (1), R １ and R ２ each independently represents an alkyl group. 【Chemistry 2】 [In formula (2), R ３ and R ４ 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, and each of m and n independently represents an integer of 0 to 4. ３ Or R ４ When there are multiple, they may be the same or different.

2. The R １ and the R ２ The aromatic polysulfone according to claim 1 , wherein is a methyl group.

3. 3. The aromatic polysulfone according to claim 1, wherein the amount of hydroxyl groups and / or salts thereof per 1 g of the aromatic polysulfone is less than 70 μmol / g.

4. 3. The aromatic polysulfone according to claim 1 or 2, having a weight average molecular weight of 30,000 or more and 70,000 or less.

5. The method includes a polymerization step of polymerizing a dihydroxy compound and a dihalogeno compound to obtain an aromatic polysulfone, The dihydroxy compound includes a compound represented by the following formula (1a) and a compound represented by the following formula (2a): The dihalogeno compound comprises a compound represented by the following formula (2b): 【Chemistry 3】 [In formula (1a), R １１ and R １２ each independently represents an alkyl group. 【Chemistry 4】 [In formula (2a), R １３ and R １４ 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, and p and q each independently represent an integer of 0 to 4. １３ Or R １４ When there are multiple, they may be the same or different. 【Chemistry 5】 [In formula (2b), X １ and X ２ Each of X independently represents a halogen atom. １ and X ２ may be the same or different. １５ and R １６ 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, and r and s each independently represent an integer of 0 to 4. １５ Or R １６ When there are multiple, they may be the same or different.

6. In the polymerization step, the dihydroxy compound includes dihydroxydiphenyl sulfone and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene; The method for producing an aromatic polysulfone according to claim 5 , wherein the dihalogeno compound comprises a dihalogenodiphenylsulfone.

7. In the polymerization step, The method for producing an aromatic polysulfone according to claim 5 , wherein a molar ratio of the dihydroxy compound to the dihalogeno compound satisfies the condition of the following formula (II): The dihydroxy compound / the dihalogeno compound≦1 Formula (II)

8. A resin composition comprising the aromatic polysulfone according to claim 1 or 2 and an epoxy resin.

9. The resin composition according to claim 8 , further comprising a curing agent.

10. A prepreg comprising the resin composition according to claim 9 and reinforcing fibers.

11. The prepreg of claim 10, wherein the reinforcing fibers are carbon fibers.

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