Polymerizable composition and method for producing polymers

Abstract

To provide naphthol resin with improved heat resistance. [Solution] The polymerizable composition comprises a naphthol resin (A) having repeating units represented by general formula (1), and maleimides (B). TIFF2026141959000009.tif39153

Description

[[Technical Field]]

[0001] The present invention relates to a polymerizable composition and a method for producing a polymer. [[Background Art]]

[0002] Due to the properties derived from having a naphthol skeleton, naphthol resins are useful in terms of heat resistance, adhesiveness, mechanical properties, electrical properties, and the like, and are widely used as molding materials for various base materials, friction materials, abrasives / grinding stones, curing agents for epoxy resins, and the like.

[0003] For example, Patent Document 1 discloses a naphthol resin having a specific structure bonded via a methyl group and a benzene ring, from the viewpoint of achieving heat resistance, low dielectric loss tangent, and low CTE. Patent Document 2 discloses an epoxy resin composition containing an α-naphthol biphenyl aralkyl-type epoxy resin and a curing agent, wherein the curing agent has an active ester structure. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] International Publication No. WO 2020 / 196604 [[Patent Document 2]] International Publication No. WO 2020 / 003824 [[Summary of the Invention]] [[Problems to be Solved by the Invention]]

[0005] However, the naphthol resin compositions disclosed in Patent Documents 1 and 2 leave room for improvement in terms of enhancing heat resistance. An object of the present invention is to provide a polymerizable composition using a naphthol resin that is more excellent in heat resistance. [[Means for Solving the Problems]]

[0006] The inventors of this invention conducted diligent research to solve the above-mentioned problems and found that it is effective to use a combination of a specific aralkyl-type naphthol resin and maleimides, thereby completing the present invention.

[0007] The present invention provides a polymerizable composition containing the naphthol resin shown below, and related technologies.

[0008] [1] A naphthol resin (A) having repeating units represented by the following general formula (1), Maleimides (B) and A polymerizable composition containing the following: [ka] (In equation (1), n ​​is an integer between 1 and 30.) [2] [1] The polymerizable composition described above, A polymerizable composition in which the maleimide (B) content is 0.05 moles to 2 moles per mole of naphthol. [3] A polymerizable composition according to [1] or [2], A polymerizable composition wherein the naphthol resin (A) has a softening point of 90 to 150°C. [4] A polymerizable composition according to any one of [1] to [3], A polymerizable composition wherein the naphthol resin (A) has a weight-average molecular weight of 1,000 to 50,000. [5] A polymer of any one of the polymerizable compositions described in [1] to [4]. The polymer described in [6] [5], A polymer with a glass transition temperature of 250°C to 400°C. [7] A naphthol resin (A) having repeating units represented by the following general formula (1), A method for producing a polymer, comprising the step of reacting maleimides (B) with [another substance]. [ka] (In equation (1), n ​​is an integer between 1 and 30.) A method for producing the polymer according to [8] or [7], wherein the method for producing a polymer comprises heating at 150 to 350° C. in the step.

Effect of the Invention

[0009] According to the present invention, there is provided a polymerizable composition that can provide excellent heat resistance.

Mode for Carrying Out the Invention

[0010] Embodiments of the present invention will be described below. In the present specification, the notation "a to b" in the description of a numerical range means "from a to b (inclusive)" unless otherwise specified. For example, "5 to 90% by mass" means "5% by mass or more and 90% by mass or less".

[0011] Unless otherwise specified, each component and material exemplified in the present specification may be used alone or in combination of two or more thereof.

[0012] <Polymerizable Composition> The polymerizable composition comprises a naphthol resin (A) having a repeating unit represented by the following general formula (1), and a maleimide (B).

[0013]

Chemical Formula

[0014] That is, it is presumed that by including, as a repeating unit, a cyclic skeleton in which a naphthol ring and a benzene ring are bonded, a rigid chemical structure is obtained and heat resistance can be improved. Further, similar to conventional phenol resins, high mechanical strength can be maintained.

[0015] Further, in formula (1), n is an integer of 1 to 30, preferably 2 to 20.

[0016] The fact that the naphthol resin (A) has a repeating unit represented by formula (1) is confirmed by 1This can be confirmed by H-NMR spectroscopy and IR spectroscopy.

[0017] The softening point of naphthol resin (A) is preferably 90 to 150°C, more preferably 100 to 130°C, and even more preferably 110 to 120°C. By setting the softening point above the lower limit mentioned above, it can be solidified at room temperature, resulting in excellent handling properties. By setting the softening point below the above upper limit, it can be used by thermal melting.

[0018] The softening point can be measured using the ring-and-ball method described in JIS K7234.

[0019] The weight-average molecular weight of naphthol resin (A) is preferably 1,000 to 50,000, more preferably 2,000 to 20,000, and even more preferably 2,500 to 6,000. By setting the weight-average molecular weight above the lower limit mentioned above, the product can be solidified at room temperature, resulting in excellent handling properties. By keeping the weight-average molecular weight below the above upper limit, it can be thermally melted.

[0020] The weight-average molecular weight can be measured using gel permeation chromatography (GPC) to obtain a polystyrene equivalent.

[0021] (Method for synthesizing naphthol resin (A)) The method for producing naphthol resin (A) is not particularly limited, and it can be obtained by polycondensation reaction of naphthols (a) and p-xylylene glycol dimethyl ether (para-xylylene glycol dimethyl ether).

[0022] The naphthols (a) described above 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.

[0023] The reaction conditions are set as appropriate, but are preferably 100-200°C for 30-240 minutes, and more preferably 120-180°C for 45-220 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 (A) can be made uniform through intermolecular entanglement and interaction. The heating temperature may be increased in stages.

[0024] An acid catalyst may be used in the reaction. As the acid catalyst, known catalysts can be used, but examples include one or more selected from 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 inorganic acids such as hydrochloric acid, sulfuric acid, sulfuric acid esters, phosphoric acid, and phosphoric acid esters.

[0025] The reaction may be carried out without solvents, or using water or an organic solvent. Specific examples of organic solvents include alcohols, ketones, and aromatics. Specific examples of alcohols include methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether, triethylene glycol, and glycerin. Specific examples of ketones include acetone and methyl ethyl ketone. Specific examples of aromatics include toluene and xylene.

[0026] Furthermore, it is preferable to continuously distill off the methanol produced during the reaction.

[0027] After the reaction, neutralization and washing with water may be performed, and then volatile components may be distilled out of the system under reduced pressure. For neutralization, various basic substances such as alkali metal hydroxides like sodium hydroxide and potassium hydroxide, ammonia, diethylenetriamine, triethylenetriamine, aniline, and phenylenediamine may be used as neutralizing agents. For washing with water, conventional methods may be followed. For example, water in which the above neutralizing agent is dissolved may be added to the reaction mixture, and the liquid-liquid extraction operation may be repeated.

[0028] [Maleimides (B)] Maleimides (B) 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'-di 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.

[0029] The maleimide (B) content is preferably 0.05 moles or more, more preferably 0.5 moles or more, and even more preferably 0.8 moles or more, per mole of naphthol. This allows for improved heat resistance while maintaining high mechanical strength. The content of maleimides (B) is preferably 2 moles or less, more preferably 1.5 moles or less, and even more preferably 1.2 moles or less, per mole of naphthol. This allows for a good balance between high mechanical strength and heat resistance.

[0030] Furthermore, the content of maleimides (B) is preferably 10 to 100 parts by mass, more preferably 30 to 85 parts by mass, and even more preferably 50 to 75 parts by mass, per 100 parts by mass of naphthol resin (A).

[0031] (others) The polymerizable composition may also contain other optional components. These optional components are not particularly limited, but examples include thermosetting resins (excluding naphthol resin), thermoplastic resins, elastomers, curing agents, curing accelerators, crosslinking agents, fillers, coupling agents, release agents, thixotropes, thickeners, dispersants, and pigments.

[0032] (Manufacturing method) The polymerizable composition can be produced using known methods, and naphthol resin (A), maleimides (B), and optional components may be mixed by grinding. Alternatively, they may be melt-kneaded using a kneader, rolls, etc. The kneaded mixture may be further processed, for example, into powder, granule, tablet, or sheet form. Alternatively, the polymerizable composition may be dissolved in an organic solvent to form a varnish. In this case, heating may be performed as needed. Subsequently, components that do not dissolve in the organic solvent, such as inorganic fillers, may be added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., to prepare a varnish-like curable resin composition. The organic solvent used here is not particularly limited as long as it dissolves each resin component and does not inhibit the curing reaction. Examples include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate, propyl acetate, and butyl acetate; polar solvents such as dimethylacetamide and dimethylformamide; and aromatic hydrocarbon solvents such as toluene and xylene. It is also possible to use one or more of these in combination.

[0033] <polymer> The polymer of this embodiment is obtained by forming a crosslinked structure in the above polymerizable composition through a Diels-Alder reaction (DA reaction) and then polymerizing it. In the DA reaction, the phenol group of naphthol resin (A) is added to the benzene ring and crosslinks with the double bond of maleimide (B).

[0034] Polymerization conditions are set as appropriate, but are preferably 150 to 350°C, and more preferably 180 to 280°C. This allows the reaction to proceed efficiently and fully.

[0035] The polymerization time is not particularly limited and can be appropriately determined depending on the type of starting materials, the molar ratio of the mixture, the amount and type of catalyst used, and the reaction conditions, but for example, it may be 30 to 240 minutes.

[0036] 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.

[0037] Polymerization may also be carried out under catalytic conditions. Known catalysts can be used, such as Lewis acid catalysts.

[0038] A polymer is obtained through the process described above.

[0039] The glass transition temperature of the polymer is preferably 250°C to 400°C, and more preferably 300°C to 350°C. By setting the glass transition temperature above the lower limit, high heat resistance can be obtained. On the other hand, by setting the glass transition temperature below the upper limit, good heat resistance can be obtained while also achieving good moldability and processability.

[0040] [Application] The polymerizable composition of this embodiment can be applied to various uses in place of conventional phenolic resin compositions, 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.

[0041] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. [Examples]

[0042] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0043] (1) Raw materials [Naphthol resin (A)] The material obtained by the following synthesis example 1 was used. <Synthesis Example 1> In a reactor equipped with a reflux condenser and stirrer, 1200 g of p-xylylene glycol dimethyl ether, 1667 g of β-naphthol, and 5 g of diethyl sulfate were added and mixed and stirred, and the temperature was raised to 140°C. The reaction was carried out for 60 minutes while the methanol produced was discharged from the system. The temperature was then raised to 160°C, and the reaction was carried out for 180 minutes while the methanol was continued to be discharged from the system. 5 g of triethylamine was added to neutralize the mixture. Then, the temperature was raised to 220°C while reducing the pressure to 68 cmHg and removing volatile components from the system. After that, the mixture was removed to obtain 2400 g of naphthol resin (A) (naphthol aralkyl resin, Mw: 3200, softening point 116°C; measured by the following method) having repeating units shown in formula (1).

[0044] [Maleimides (B)] Maleimides 1: Bismaleimide (manufactured by Yamato Chemical Co., Ltd.) "BMI-3000H" N,N'-1,3-phenylenedimaleimide • Maleimide 2: Maleimide resin (manufactured by Yamato Kasei Co., Ltd.) "BMI-2300"

[0045] (2) Measurement The following measurements were performed on the obtained naphthol resin (A). [Softening point] Measurements were taken in accordance with the ring-sphere method described in JIS K7234.

[0046] [Weight average molecular weight] The GPC system "HLC-8420GPC EcoSEC Elite (manufactured by Tosoh Corporation)" was connected in series with the following general-purpose organic columns packed with styrene-based polymer packing: "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)". In this GPC system, 30 μL of the sample was injected, and at 40°C, N-methyl-2-pyrrolidone eluent was developed at a rate of 0.3 mL / min. The retention time was then measured using differential refractive index (RI) and ultraviolet absorbance (UV). The weight-average molecular weight was calculated from a calibration curve showing the relationship between retention time and molecular weight of standard polystyrene, which had been prepared separately. Refractive index was used as the detection mode. Standard polystyrene (manufactured by Tosoh Corporation) was used to create the calibration curve.

[0047] (3) Polymerizable composition <Example 1> Polymerizable composition 1 was prepared by mixing the raw materials to achieve the composition shown in Table 1. Polymerizable composition 1 forms a crosslinked structure as shown in the following formula (X1).

[0048] [ka]

[0049] <Example 2> Polymerizable composition 2 was prepared by mixing the raw materials to achieve the composition shown in Table 1. Polymerizable composition 2 forms a crosslinked structure as shown in the following formula (X2).

[0050] [ka]

[0051] <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.

[0052] (4) Evaluation The polymers of each polymerizable composition obtained in the examples and comparative examples were evaluated as follows. The results are shown in Table 1.

[0053] [Glass transition temperature] Measurements were taken in accordance with JIS K 7121-2012.

[0054] [Heat resistance: 20% mass reduction start temperature] Polymers were obtained by heating the polymerizable compositions of each example and comparative example at 280°C for 1 hour. Next, 5 mg of the polymer obtained above was placed in a thermogravimetric / differential thermal analyzer (Hitachi High-Tech Science Corporation, STA7200RV). Subsequently, thermogravimetric / differential thermal measurements were performed on the polymer in accordance with JIS K 7120:1987, under the conditions of inlet 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 placed polymer 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.

[0055] [Tensile strength] The following physical properties were measured for the polymer obtained above. The resin was diluted with methyl ethyl ketone (MEK) to a solid content of 33%, impregnated into a 120mm x 10mm x 1mm thick filter paper, and then dried and cured in an oven at 280°C for 60 minutes to obtain the resin-impregnated paper, which was used as the test specimen.

[0056] [Table 1]

Claims

1. A naphthol resin (A) having repeating units represented by the following general formula (1), Maleimides (B) and A polymerizable composition containing the following: 【Chemistry 1】 (In equation (1), n ​​is an integer between 1 and 30.)

2. A polymerizable composition according to claim 1, A polymerizable composition in which the maleimide (B) content is 0.05 moles to 2 moles per mole of naphthol.

3. A polymerizable composition according to claim 1 or 2, A polymerizable composition wherein the naphthol resin (A) has a softening point of 90 to 150°C.

4. A polymerizable composition according to claim 1 or 2, A polymerizable composition wherein the naphthol resin (A) has a weight-average molecular weight of 1,000 to 50,000.

5. A polymer of the polymerizable composition according to claim 1 or 2.

6. The polymer according to claim 5, A polymer having a glass transition temperature of 250°C to 400°C.

7. A naphthol resin (A) having repeating units represented by the following general formula (1), A method for producing a polymer, comprising the step of reacting maleimides (B) with [another substance]. 【Chemistry 2】 (In equation (1), n ​​is an integer between 1 and 30.)

8. A method for producing a polymer according to claim 7, A method for producing a polymer, wherein the process involves heating at 150 to 350°C.

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