Naphthol resin, polyimide resin composition, and cured product

Abstract

To provide naphthol resin with improved heat resistance. [Solution] The naphthol resin has repeating units represented by the following formula (1-1) or similar repeating units. This naphthol resin is produced by a manufacturing method that includes a step of polymerizing naphthols with at least one of maleic anhydride and maleimides. TIFF2026099036000020.tif53153 (In the formula, A represents an oxygen atom or a nitrogen atom which may have substituents, and R1 represents a divalent organic group having methylene groups at both ends. n is an integer from 1 to 50.)

Description

Technical Field

[0001] The present invention relates to a naphthol resin, a polyimide resin composition, and a cured product.

Background Art

[0002] Phenolic resins are useful in terms of heat resistance, adhesiveness, mechanical properties, electrical properties, etc., and are widely used as molding materials for various base materials, friction materials, grinding materials and abrasive stones, and curing agents for epoxy resins, etc., and improvements are being made. For example, from the point of further enhancing the heat resistance of phenolic resins, it is known to use phenolic aralkyl resins, phenolic biphenyl aralkyl resins, etc.

[0003] On the other hand, in order to further enhance the properties of phenolic resins, attempts have been made to apply naphthol resins instead of phenolic resins. For example, Patent Document 1 discloses a technique for producing a naphthol aralkyl resin by using naphthol as a phenolic compound in contrast to the prior art of producing a phenolic aralkyl resin by the reaction of a phenolic compound and p-xylene glycol dimethyl ether. Specifically, Patent Document 1 discloses a method for producing a naphthol aralkyl resin in which when reacting naphthol and p-xylene glycol dimethyl ether in the presence of a catalyst, the pressure in the reaction system is set to 10 to 600 mmHg, and the methanol produced is continuously distilled out of the system to reduce by-products.

[0004] Also, as an addition reaction product of naphthol, Non-Patent Document 1 discloses a reaction product of β-naphthol and maleic anhydride. According to Non-Patent Document 1, by reacting β-naphthol and maleic anhydride, a reaction product having the structure represented by the following formula (I) can be obtained.

[0005]

Chemical formula

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Application Publication No. 05-155985 [Non-patent literature]

[0007] [Non-Patent Document 1] Takeda, Kenichi; Kitaboku, Keizo. "Reaction of β-Naphthol with Maleic Anhydride," Journal of Pharmaceutical Sciences, The Pharmaceutical Society of Japan, Vol. 73, pp. 280-283 (1953). [Overview of the project] [Problems that the invention aims to solve]

[0008] The inventors of this case focused on improving the properties of phenolic resins by using naphthol resin instead of conventional phenolic resins. They found that naphthol resins, such as those described in Patent Document 1, have room for improvement in terms of achieving higher heat resistance than phenolic resins. Therefore, we focused on developing a new naphthol resin using naphthol reaction products as described in Non-Patent Document 1, and after diligent research, we discovered that a naphthol resin with high heat resistance can be obtained by polymerizing a predetermined naphthol compound via a methylene group, thus completing the present invention. [Means for solving the problem]

[0009] According to the present invention, the following naphthol resin and related technologies are provided.

[0010] [1] A naphthol resin having at least one of the following repeating units represented by formula (1-1) or formula (1-2). [ka] [ka] (In formulas (1-1) and (1-2), A represents oxygen or a nitrogen atom which may have a substituent, R1 represents a divalent organic group having methylene groups at both ends, and n represents an integer of 1 to 50.) [2] The naphthol resin according to [1], A naphthol resin having a softening point of 60 to 200 °C. [3] The naphthol resin according to [1] or [2], A naphthol resin having a weight average molecular weight of 500 to 10,000. [4] A method for producing the naphthol resin according to any one of [1] to [3], which comprises a step of subjecting naphthols represented by the following formula (2) and at least one of maleic anhydride and maleimides to a polymerization reaction.

Chemical formula

Advantages of the Invention

[0011] According to the present invention, there is provided a naphthol resin capable of obtaining excellent heat resistance.

Brief Description of the Drawings

[0012] [Figure 1]It is a diagram showing the 1H-NMR spectrum of the naphthol resin A1 of the example. [Figure 2] It is a diagram showing the IR spectrum of the naphthol resin A1 of the example.

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described. In this specification, the notation "a~b" in the description of a numerical range means "a or more and b or less" unless otherwise specified. For example, "5~90 mass%" means "5 mass% or more and 90 mass% or less".

[0014] Each component and material exemplified in this specification may be used alone or in combination of two or more, unless otherwise specified.

[0015] <Naphthol Resin> The naphthol resin has at least one of the repeating units represented by the following formula (1-1) or formula (1-2). That is, by including a cyclic skeleton in which a 5-membered ring is added to the naphthol ring as a repeating unit, it is presumed that a rigid chemical structure can be obtained and the heat resistance can be improved.

[0016]

Chemical formula

[0017]

Chemical formula

[0018] (In formula (1-1) and formula (1-2), A represents oxygen or a nitrogen atom which may have a substituent, and R1 represents a divalent organic group having methylene groups at both ends. n is an integer of 1 to 50.)

[0019] In formula (1-1) and formula (1-2), A represents oxygen or a nitrogen atom which may have a substituent. Substituents for the nitrogen atom are not particularly limited, but include substituted or unsubstituted aliphatic groups having 1 to 100 carbon atoms, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic groups, and combinations thereof. More specifically, A can be oxygen, an unsubstituted nitrogen atom, a nitrogen atom substituted with a methyl group, a nitrogen atom substituted with a cyclohexyl group, or a nitrogen atom substituted with a benzyl group. By controlling the solubility of the monomer through its stereostructure, these components lead to increased molecular weight during resin formation, thereby improving heat resistance. Among these, A being oxygen or an unsubstituted nitrogen atom is preferred.

[0020] In formulas (1-1) and (1-2), R1 represents a divalent organic group having methylene groups at both ends. That is, in this embodiment, the naphthol resin is polymerized by a naphthalene skeleton via methylene groups.

[0021] The divalent organic group having methylene groups at both ends is not particularly limited, but is an organic group having 1 to 15 carbon atoms and may include divalent aliphatic groups that may have substituents such as hydroxyl groups and carboxyl groups, or aromatic groups that may have substituents such as phenol groups, carboxyl groups and hydrocarbon groups, and combinations thereof. An example of the aromatic group that may have substituents such as hydrocarbon groups is a benzyl group that may have substituents. More specifically, an unsubstituted benzyl group and a benzyl group substituted with a hydroxyl group are preferred.

[0022] Furthermore, in equations (1-1) and (1-2), n is an integer between 1 and 50, preferably between 2 and 50.

[0023] The naphthol resin has repeating units represented by formula (1-1) or formula (1-2), 1 This can be confirmed by H-NMR spectroscopy and IR spectroscopy. Further details will be explained in the examples.

[0024] The softening point of naphthol resin is preferably 60 to 200°C, more preferably 80 to 180°C, and even more preferably 90 to 160°C. By setting the softening point above the lower limit mentioned above, the material can be solidified at room temperature, resulting in excellent handling properties. Furthermore, from the viewpoint of obtaining higher heat resistance, a temperature of 100°C or higher is preferable, 110°C or higher is more preferable, and 130°C or higher is even preferable. By setting the softening point below the above upper limit, it can be used by thermal melting.

[0025] The softening point can be measured using the ring-and-ball method described in JIS K7234. The softening point of naphthol resin can be adjusted by controlling the reaction ratio between naphthols and the compounds they react with.

[0026] The weight-average molecular weight of the naphthol resin is preferably 500 to 10000, more preferably 600 to 9000, and even more preferably 700 to 8000. By setting the weight-average molecular weight to be above the lower limit mentioned above, it can be solidified at room temperature and has excellent handling properties. Furthermore, from the viewpoint of obtaining higher heat resistance, a molecular weight of 1000 or more is preferable, 1500 or more is more preferable, 1600 or more is even preferable, and 1800 or more is even preferable. By keeping the weight-average molecular weight below the above upper limit, it can be thermally melted.

[0027] The weight-average molecular weight can be measured using gel permeation chromatography (GPC) to obtain a polystyrene equivalent. The weight-average molecular weight of naphthol resin can be adjusted by controlling the reaction ratio between naphthols and the compounds they react with.

[0028] <Method for producing naphthol resin> A method for producing naphthol resin comprises the step of polymerizing naphthols represented by the following formula (2) with at least one of maleic anhydride and maleimides.

[0029] [ka]

[0030] (In formula (2), R2 and R3 are organic groups having 1 to 15 carbon atoms, and may be the same or different from each other, both of which are bonded to the naphthol ring via a methylene group.)

[0031] In formula (2), R2 and R3 are each organic groups having 1 to 15 carbon atoms, and examples include divalent aliphatic groups which may have substituents such as hydroxyl groups and carboxyl groups, or aromatic groups which may have substituents such as phenol groups, carboxyl groups and hydrocarbon groups, and combinations thereof. An example of an aromatic group which may have substituents such as hydrocarbon groups is a benzyl group which may have substituents. More specifically, an unsubstituted benzyl group and a benzyl group which has a substituent with a hydroxyl group are preferred. Furthermore, naphthol may be either 1-naphthol (α-naphthol) or 2-naphthol (β-naphthol), but 2-naphthol (β-naphthol) is preferred in terms of obtaining reaction stability.

[0032] Examples of naphthol compounds represented by formula (2) include those obtained by reacting 1,4-bis(methoxymethyl)benzene with naphthol, and those obtained by reacting phenol, formaldehyde, and naphthol.

[0033] Maleimides include maleimides; alkylmaleimides such as methylmaleimide, ethylmaleimide, and cyclohexylmaleimide; arylmaleimides such as phenylmaleimide; 1,6-bis(maleimide)hexane, 1,10-bis(maleimide)decane, 1,3-phenylenebismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, m-xylenebismaleimide, and N,N'-bismaleimide-4,4'-diphenylmethanebismaleimide. Examples of bismaleimides include phenylmethane, 1,6-bismaleimide(2,2,4-trimethyl)hexane, 4-methyl-1,3-phenylenebismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, 1,3-bis(citraconimidomethyl)benzene, bisphenol A diphenyl ether bismaleimide, and 2,2'-bis-[4-(4-maleimidophenoxy)phenyl]propane. These may be used individually or in combination of two or more types.

[0034] The total number of moles of maleic anhydride and maleimide is preferably 0.05 moles to 2 moles, more preferably 0.1 moles to 1.5 moles, and even more preferably 0.1 moles to 1.0 mole per mole of naphthol.

[0035] Furthermore, the polymerization of naphthols with at least one of maleic anhydride and maleimides may be carried out under acid catalysis. As the acid catalyst, known catalysts can be used, but examples include organic acids such as acetic acid, formic acid, oxalic acid, malonic acid, succinic acid, maleic acid, glutaric acid, adipic acid, benzoic acid, salicylic acid, sulfonic acid, phenolsulfonic acid, and p-toluenesulfonic acid; or one or more selected from inorganic acids such as hydrochloric acid, sulfuric acid, sulfuric acid esters, phosphoric acid, and phosphoric acid esters. Among these, maleic acid is preferred.

[0036] Polymerization conditions are set as appropriate, but it is preferable to set them at 180-240°C for 30-240 minutes. This allows the reaction to proceed efficiently and sufficiently. Furthermore, by carrying out the reaction under heating, the starting materials are uniformly mixed, and the molecular weight of the resulting naphthol resin can be made uniform through intermolecular entanglement and interaction. There are no particular restrictions on the polymerization time; it can be determined appropriately depending on the type of starting materials, the molar ratio of the materials, the amount and type of catalyst used, and the reaction conditions.

[0037] Water or an organic solvent may be used as the reaction solvent. Specific examples of organic solvents include alcohols, ketones, and aromatics. Specific examples of alcohols include methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, and glycerin. Specific examples of ketones include acetone and methyl ethyl ketone. Specific examples of aromatics include toluene and xylene.

[0038] Through the above process, a naphthol resin having at least one of the repeating units represented by formula (1-1) or formula (1-2) is obtained.

[0039] [Naphthol resin composition] The naphthol resin composition is a mixture containing the naphthol resin described above and optional components depending on the function and application. The optional components are not particularly limited, but examples include thermosetting resins other than naphthol resin, thermoplastic resins, elastomers, curing agents, curing accelerators, crosslinking agents, fillers, coupling agents, mold release agents, thixotropes, thickeners, dispersants, and pigments.

[0040] The naphthol resin composition can be produced using known methods, and is obtained by melt-kneading naphthol resin and optional components using a kneader, rolls, etc. The kneaded mixture may be further processed, for example, into powder, granule, tablet, or sheet form.

[0041] [Uses of naphthol resin and naphthol resin compositions] The naphthol resin of this embodiment can be used in place of conventional phenolic resins for a variety of applications, but is particularly preferred in applications requiring high heat resistance. Examples include molded products used in automobiles, aircraft, railway vehicles, ships, general-purpose machinery, household electrical appliances, cooking utensils and their peripheral parts, or molded products used in their housings, structural and mechanical parts, and electrical and electronic components. More specifically, examples include friction materials such as brake pads that control the driving and movement of molded products, adhesives for friction materials, and grinding wheels that require heat resistance during cutting and polishing. Furthermore, the naphthol resin of this embodiment may be used instead of the phenolic resin used as a curing agent for conventional epoxy resins, etc.

[0042] <Polyimide resin> Polyimide resin is obtained by the reaction of the naphthol resin described above with a polyamine compound.

[0043] The polyamine compound is not particularly limited as long as it is an amine compound having two or more amino groups in its molecular structure, but examples include alicyclic polyamine compounds containing an alicyclic structure, aromatic polyamines (aniline derivatives), and aniline resins.

[0044] Furthermore, specific examples of alicyclic diamine compounds include isophoronediamine, norbornanediamine, 1,6-cyclohexanediamine, and piperazine.

[0045] Furthermore, specific examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, and 5-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan 6-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan, 4,4'-diaminobenzanilide, 3,5-diamino-3'-trifluoromethylbenzanilide, 3,5-diamino-4'-trifluoromethylbenzanilide, 3,4'-diaminodiphenyl ether, 2,7-diaminofluorene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-methylene-bis(2-chloroaniline), 2,2',5,5'-tetrachloro-4,4 '-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy) Examples include -biphenyl, 1,3'-bis(4-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-(p-phenyleneisopropylidene)bisaniline, 4,4'-(m-phenyleneisopropylidene)bisaniline, 2,2'-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, and 4,4'-bis[4-(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl.

[0046] Aniline resins are resins obtained by the condensation reaction of anilines and aldehydes. The weight-average molecular weight of aniline resins, calculated on a polystyrene basis using GPC, is preferably 200 to 10000, more preferably 800 to 3000, and even more preferably 1000 to 2000.

[0047] The conditions for obtaining polyimide resin are set as appropriate, but for example, by dissolving the above-mentioned naphthol resin and a polyamine compound in a solvent such as cyclohexanone and reacting them at 60°C for about 10 hours, amic acid, a precursor of polyimide resin, can be obtained. By heating this at a temperature of 250°C or higher, it can be imidized to obtain polyimide resin. This allows the reaction to proceed efficiently and sufficiently. Furthermore, by carrying out the reaction under heating, the starting materials are uniformly mixed, and the molecular weight of the resulting polyimide resin can be made uniform through intermolecular entanglement and interaction. There are no particular restrictions on the reaction time; it can be determined appropriately depending on the type of starting materials, the molar ratio of the materials, the amount and type of catalyst used, and the reaction conditions.

[0048] The weight-average molecular weight of the polyimide resin is preferably 1,000 to 50,000, more preferably 3,000 to 30,000, and even more preferably 5,000 to 10,000.

[0049] The weight-average molecular weight of polyimide resin can be measured by converting it to polystyrene equivalent using gel permeation chromatography (GPC). The weight-average molecular weight of polyimide resin can be adjusted by controlling factors such as the selection of naphthol resin, reaction temperature, and reaction time.

[0050] [Polyimide resin composition] The polyimide resin composition contains the above-mentioned polyimide resin. The polyimide resin content is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass, based on the total amount of the polyimide resin composition. This allows for good heat resistance and mechanical strength of the cured product obtained by curing the polyimide resin composition.

[0051] The polyimide resin composition may further contain optional components depending on its function and application. While not particularly limited, optional components include, for example, thermosetting resins other than polyimide resin, thermoplastic resins, elastomers, curing agents, curing accelerators, crosslinking agents, fillers, coupling agents, mold release agents, thixotropes, thickeners, dispersants, and pigments.

[0052] A known method can be used to produce the polyimide resin composition, which is obtained by melt-kneading naphthol resin and optional components using a kneader, rolls, etc. The kneaded mixture may be further processed, for example, into powder, granule, tablet, or sheet form.

[0053] [Cured polyimide resin composition] The polyimide resin composition can be cured at 200-350°C for 30-300 minutes. A desired cured product can be obtained by heat-treating and curing a polyimide resin composition. While there are no particular limitations on the method for molding the cured product, examples include transfer molding, compression molding, and injection molding using the polyimide resin composition.

[0054] [Uses of polyimide resin compositions] The polyimide resin composition of this embodiment can be applied to a variety of uses, but is particularly preferred in applications requiring high heat resistance. Examples include molded articles used in automobiles, aircraft, railway vehicles, ships, general-purpose machinery, household electrical appliances, cooking utensils and their peripheral parts, or molded articles used in their housings, structural and mechanical parts, and electrical and electronic components. More specifically, examples include friction materials such as brake pads that control the driving and movement of molded articles, adhesives for friction materials, and grinding wheels that require heat resistance during cutting and polishing.

[0055] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. [Examples]

[0056] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0057] (1) Raw materials Naphthol resins A1 to A3 were prepared using the following procedure.

[0058] <Polymerization of naphthol resin A1> In a reactor equipped with a reflux condenser and stirrer, 150 g of p-xylylene glycol dimethyl ether, 230 g of β-naphthol, and 1 g of diethyl sulfuric acid were added and mixed and stirred, and the temperature was raised to 140°C. The reaction was carried out for 180 minutes while removing the methanol produced from the system. The temperature was then raised to 160°C, and the reaction was carried out for another 180 minutes while removing the methanol from the system. 0.7 g of triethylamine was added to neutralize the mixture, and the temperature was raised to 220°C while reducing the pressure to 68 cmHg and removing volatile components from the system. Subsequently, 110 g of maleic anhydride was added, and the reaction was carried out for 180 minutes while maintaining the temperature at 220°C to obtain 445 g of naphthol resin A1 (maleated naphthol aralkyl resin) shown in the following formula (A1).

[0059] [ka] (In the formula, * indicates a link between repeating units.)

[0060] <Polymerization of naphthol resin A2> In a reactor equipped with a reflux condenser and stirrer, 100 g of phenol, 55 g of β-naphthol, and 1.5 g of oxalic acid were added and the temperature was raised to 100°C. A 37% formaldehyde aqueous solution was gradually added at 100°C over 60 minutes. The reaction was then carried out at 100°C for 180 minutes. The temperature was raised to 140°C while draining water from the system at atmospheric pressure, and then raised to 220°C while reducing the pressure to 68 cmHg and draining volatile components from the system. Subsequently, 30 g of maleic anhydride was added, and the reaction was carried out at 220°C for 180 minutes to obtain 155 g of naphthol resin A2 (maleated naphthol-phenol-formaldehyde resin) shown in the following formula (A2).

[0061] [ka] (In the formula, * indicates a link between repeating units.)

[0062] <Polymerization of naphthol resin A3> The same method as in Example 2 was used for synthesis, except that phenol was replaced with o-cresol, to obtain 150 g of naphthol resin A3 (maleated naphthol-cresol-formaldehyde resin) represented by the following formula (A3).

[0063] [ka] (In the formula, * indicates a link between repeating units.)

[0064] (2) Examples and Comparative Examples [Example 1] <Synthesis of Polyimide Resin B1> 60 g of naphthol resin A1 and 40 g of polyamine compound 1 (aniline formaldehyde resin, manufactured by Sumitomo Bakelite Co., Ltd., mass-average molecular weight: 1500, average number of amino groups: 15, melting point: 75°C) were dissolved in 200 g of cyclohexanone and reacted at 60°C for about 10 hours to obtain amicoic acid, a precursor of polyimide resin B1 shown in the following formula (B1).

[0065] [ka] (In the formula, * indicates a link between repeating units.)

[0066] [Example 2] <Synthesis of Polyimide Resin B2> 60 g of naphthol resin A1 and 40 g of polyamine compound 2 (4,4'-diaminodiphenyl ether, "BMI-3000H" manufactured by Yamato Kasei Co., Ltd.) were dispersed in 200 g of cyclohexanone and reacted at 60°C for about 10 hours to obtain amicoic acid, a precursor of polyimide resin B2 shown in the following formula (B2).

[0067] [ka] (In the formula, * indicates a link between repeating units.)

[0068] [Example 3] <Synthesis of Polyimide Resin B3> 60 g of naphthol resin A2 and 40 g of polyamine compound 2 were dissolved in 200 g of cyclohexanone and reacted at 60°C for about 10 hours to obtain amicoic acid, a precursor of polyimide resin B3, shown in the following formula (B3).

[0069] [ka] (In the formula, * indicates a link between repeating units.)

[0070] [Example 4] <Synthesis of Polyimide Resin B4> 60 g of naphthol resin A3 and 40 g of polyamine compound 1 were dissolved in 200 g of cyclohexanone and reacted at 60°C for about 10 hours to obtain amicoic acid, a precursor of polyimide resin B4, shown in the following formula (B4).

[0071] [ka] (In the formula, * indicates a link between repeating units.)

[0072] [Comparative Example 1] In a reaction apparatus equipped with a stirrer, reflux condenser, and thermometer, 1000 parts by mass of phenol was added to 740 parts by mass of an aqueous formalin solution (formalin content: 37% by mass) and 20 parts by mass of triethylamine, so that the molar ratio of phenol to phenol was 1. The reaction was carried out at 100°C for 30 minutes with stirring. Next, under reduced pressure of 91 kPa, dehydration was carried out, and when the temperature in the system reached 65°C, 1000 parts by mass of methyl ethyl ketone (MEK) was added to dissolve the reactants, and then the mixture was cooled. In this way, 2100 parts by mass of liquid unmodified resol-type phenolic resin (non-volatile content (solids) content: 45% by mass) was obtained. The obtained liquid, unmodified resol-type phenolic resin had a weight-average molecular weight (Mw) of 900 and a dispersion degree (Mw / Mn) of 2.5.

[0073] (3) Structural analysis Regarding naphthol resins A1 to A3, under the following conditions: 1 1H-NMR and IR spectra were measured to confirm that naphthol resins A1 to A3 have the structures shown in formulas (A1) to (A3), respectively. Figure 1 shows the structure of naphthol resin A1. 1 Figure 2 shows the 1H-NMR spectrum measurement results, and Figure 2 shows the IR spectrum measurement results for naphthol resin A1, respectively.

[0074] < 1 H-NMR measurement conditions> Equipment: JEOL Ltd. JNM-ECA400 Solvent: Heavy acetone Pulse angle: 45° Sample concentration: 3 wt% Number of integrations: 16 times

[0075] <FT-IR measurement conditions> · Fourier transform infrared spectroscopic analyzer: Performed by the single reflection ATR method using the FT-IR Nicolect iS20 manufactured by Thermo Scientific.

[0076] (4) Physical properties [Softening point] Measured in accordance with the ring and ball method described in JIS K7234. The results are shown in Table 2.

[0077] [Weight average molecular weight] For the GPC system "HLC-8420GPC EcoSEC Elite (manufactured by Tosoh Corporation)", the organic general-purpose columns filled with styrene-based polymer fillers "TSKgel SuperAW4000 (manufactured by Tosoh Corporation)", "TSKgel SuperAW3000 (manufactured by Tosoh Corporation)", "TSKgel SuperAW2500 (manufactured by Tosoh Corporation)", and "TSKgel SuperAW2500 (manufactured by Tosoh Corporation)" were connected in series. 30 μL of the measurement sample was injected into this GPC system, and at 40 °C, the eluent N-methyl-2-pyrrolidone was developed at 0.3 mL / min, and the retention time was measured using differential refractive index (RI) and ultraviolet absorbance (UV). The weight average molecular weight was calculated from the calibration curve showing the relationship between the retention time and molecular weight of the standard polystyrene prepared separately. The detection mode was refractive index. Standard polystyrene (manufactured by Tosoh) was used to create the calibration curve.

[0078] (5) Evaluation For each polyimide resin of the examples shown in Table 1 and the phenolic resin of the comparative example, the following evaluations were performed. The results are shown in Table 1.

[0079] [Heat resistance: 20% mass loss start temperature] Cured products were obtained by heating the resins of each example and comparative example at 280°C for 1 hour. Next, 5 mg of the obtained cured material was placed in a thermogravimetric / differential thermal analyzer (STA7200RV, Hitachi High-Tech Science Co., Ltd.). Then, thermogravimetric / differential thermal analysis was performed on the cured material in accordance with JIS K 7120:1987, under the conditions of inflow gas: nitrogen, measurement temperature range: 25°C to 500°C, and heating rate: 10°C / min. At this time, the temperature at which a 20% mass loss occurred relative to the mass of the set cured material was read and defined as the 20% mass loss onset temperature (°C). A higher temperature at which a 20% mass reduction begins indicates higher heat resistance.

[0080] [Tensile strength] The following physical properties were measured for the cured product of the resin composition obtained above. The obtained resin composition was diluted with methyl ethyl ketone (MEK) to a solid content of 30%, impregnated into a 120 mm × 10 mm × 1 mm thick filter paper, and then dried and cured in an oven at 280°C for 60 minutes. The resulting resin-impregnated paper was used as a test specimen. The test specimen was heat-treated at 250°C for 1 hour, and the tensile strength -1 before the heat treatment and the tensile strength -2 after the heat treatment were measured. Tensile strength was measured using an autograph.

[0081] [Table 1]

[0082] [Table 2]

Claims

1. A naphthol resin having at least one of the repeating units represented by the following formula (1-1) or formula (1-2). 【Chemistry 1】 【Chemistry 2】 (In formulas (1-1) and (1-2), A represents oxygen or a nitrogen atom which may have substituents, and R1 represents a divalent organic group having methylene groups at both ends. n is an integer from 1 to 50.)

2. The naphthol resin according to claim 1, Naphthol resin with a softening point of 60 to 200°C.

3. The naphthol resin according to claim 1 or 2, Naphthol resin with a weight-average molecular weight of 500 to 10,000.

4. A method for producing naphthol resin according to claim 1 or 2, A method for producing naphthol resin, comprising the step of polymerizing naphthols represented by the following formula (2) with at least one of maleic anhydride and maleimides. 【Transformation 3】 (In formula (2), R2 and R3 are organic groups having 1 to 15 carbon atoms, and may be the same or different from each other, and both are bonded to the naphthol ring via a methylene group.)

5. A polyimide resin obtained by reacting a naphthol resin according to claim 1 or 2 with a polyamine compound.

6. The polyimide resin according to claim 5, A polyimide resin with an average weight molecular weight of 500 to 10,000.

7. A polyimide resin composition comprising the naphthol resin according to claim 1 or 2 and a polyamine compound.

8. A cured product of the polyimide resin composition according to claim 7.

Images