Flame-retardant polyphenylene ether and its manufacturing method, as well as flame-retardant polyphenylene ether resin composition and cured product

Abstract

The present invention aims to provide a flame-retardant polyphenylene ether with a low molecular weight, excellent solubility in solvents, high flame retardancy, and crosslinking properties due to radical reactions, as well as a method for producing the same, a flame-retardant polyphenylene ether resin composition, and a cured product. [Solution] A flame-retardant polyphenylene ether represented by the following general formula (1) is used, wherein the number-average molecular weight in terms of standard polystyrene, as measured by gel permeation chromatography, is 1,000 to 10,000. [Formula 1] JPEG2026085830000013.jpg25142 (In the formula, R is either absent or represents an alkylene group with 1 to 6 carbon atoms, -S-, or -SO2-, R 1 ~R 4 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and n is an integer greater than or equal to 1.

Description

Technical Field

[0001] The present invention relates to a polyphenylene ether having excellent flame retardancy, a method for producing the same, a flame retardant polyphenylene ether resin composition, and a cured product.

Background Art

[0002] Polyphenylene ether is used as a resin material in electronic circuit board materials and the like that require low transmission loss because it has excellent dielectric properties (low dielectric constant and low dielectric tangent) in the high frequency band. Among them, a crosslinkable polyphenylene ether having a low molecular weight, excellent solubility in a solvent, and functional groups capable of chemical conversion at both ends is used as a resin material. In electronic material applications, since a resin material is required to have flame retardancy, a flame retardant is added to the resin. However, since the physical properties of the resin may be impaired by adding a flame retardant, a polyphenylene ether having a higher degree of flame retardancy is required.

[0003] Patent Document 1 discloses a method for producing a flame retardant polyphenylene ether containing halogen by an oxidative co-condensation reaction of a 2,6-disubstituted phenol and a polyvalent halogenated phenol in the presence of a catalyst. However, the obtained polyphenylene ether has a bromine content that is not sufficient to contribute to flame retardancy, and when the present inventors conducted a follow-up test, the solubility in a solvent was low because the molecular weight was large (see Comparative Example 1 in this specification).

[0004] Patent Document 2 discloses a method for producing a flame retardant halogenated polyphenylene ether characterized by reacting a polyphenylene ether with a halogenated phenol. However, when the present inventors conducted a follow-up test, a halogenated polyphenylene ether having a low molecular weight and a high bromine content could not be obtained (see Comparative Example 2 in this specification).

[0005] Moreover, examples of the composition containing a crosslinkable polyphenylene ether include the composition described in Patent Document 3.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Conventionally known flame-retardant polyphenylene ether has problems in that its solubility in solvents is low, the bromine content rate contributing to flame retardancy is insufficient, and its crosslinkability by radical reaction is also insufficient.

[0008] The present invention has been made in view of the above background art, and an object thereof is to provide a polyphenylene ether having excellent solubility in solvents, high flame retardancy, and crosslinkability by radical reaction.

Means for Solving the Problems

[0009] As a result of intensive studies, the present inventors have found that the following invention can solve the above problems, and have completed the present invention.

[0010] That is, the present invention relates to a flame-retardant polyphenylene ether shown below, a method for producing the same, a flame-retardant polyphenylene ether resin composition, and a cured product.

[0011] [1] A flame-retardant polyphenylene ether represented by the following general formula (1), characterized in that the number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography is 1,000 to 10,000.

[0012] [[ID=5​

[0013] (In the formula, R is either absent or represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, R 1 ~R 4 Each of these independently represents a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, and an alkenyl group with 2 to 6 carbon atoms, R 5 (where n represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more.) [2] The flame-retardant polyphenylene ether described in [1], wherein the number-average molecular weight in terms of standard polystyrene, as measured by gel permeation chromatography, is 1,000 to 5,000.

[0014] [3] A flame-retardant polyphenylene ether according to [1] or [2], wherein the bromine content is 5% by weight or more.

[0015] [4] The flame-retardant polyphenylene ether according to [1] or [2], characterized in that, in general formula (1), R is a 2,2-propylene group and the bromine content is 5% by weight or more.

[0016] [5] A flame-retardant polyphenylene ether according to any one of [1] to [4], wherein the solubility in toluene at 20°C is 10% by weight or more.

[0017] [6] A method for producing a flame-retardant polyphenylene ether according to any one of [1] to [5], comprising reacting a polyfunctional polyphenylene ether represented by the following general formula (2) with (meth)acrylic anhydride or (meth)acrylic halide in the presence of a solvent.

[0018] [ka]

[0019] (In the formula, R is either absent or represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, R 1 ~R 4 Each of these independently represents a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, and an alkenyl group with 2 to 6 carbon atoms, where n is an integer greater than or equal to 1. [7] A flame-retardant polyphenylene ether resin composition comprising a flame-retardant polyphenylene ether described in any of [1] to [5].

[0020] [8] Furthermore, the flame-retardant polyphenylene ether resin composition according to [7] further comprises one or more components selected from the group consisting of crosslinking agents, thermal polymerization initiators, solvents, and inorganic fillers.

[0021] [9] A cured product obtained by curing the flame-retardant polyphenylene ether resin composition described in [7] or [8]. [Effects of the Invention]

[0022] The flame-retardant polyphenylene ether of the present invention exhibits superior solubility in solvents and high flame retardancy compared to conventionally known flame-retardant polyphenylene ethers, as well as the effect of crosslinking by radical reaction. Furthermore, the cured product obtained by curing a resin composition containing the flame-retardant polyphenylene ether of the present invention exhibits higher flame retardancy compared to cured products obtained by curing a resin composition containing a conventionally known polyphenylene ether. [Modes for carrying out the invention]

[0023] The present invention will be described in more detail below.

[0024] One aspect of the present invention relates to a flame-retardant polyphenylene ether represented by the following general formula (1).

[0025] [ka]

[0026] (In the formula, R does not exist, or represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, and R 1 ~R 4 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and R 5 represents a hydrogen atom or a methyl group, and n represents an integer of 1 or more.) In the general formula (1), the alkylene group having 1 to 6 carbon atoms represented by R is not particularly limited, and examples thereof include a methylene group, an ethylene group, a 2,2-propylene group, a 2,2-butylene group, a hexadiene group, or a 1,1-cyclohexylene group.

[0027] In the general formula (1), R is preferably an alkylene group having 1 to 3 carbon atoms, and more preferably a 2,2-propylene group, in terms of excellent heat resistance and the like of the flame-retardant polyphenylene ether.

[0028] In the general formula (1), R 1 ~R<000001​​​​​​​​​​​​​​​​​​In general formula (1), n ​​represents the average number of repetitions of the repeating unit of the flame-retardant polyphenylene ether, and in the present invention, n represents an integer of 1 or more.

[0032] For example, if R is a 2,2-propylene group, 1 , R 2 , is a methyl group, R 3 , R 4 , is a hydrogen atom, R 5 When n is a methyl group and n is 20, the theoretical average molecular weight of the flame-retardant polyphenylene ether of the present invention is 3,083.

[0033] One example of a flame-retardant polyphenylene ether represented by general formula (1) is a compound having the structure shown in formula (3).

[0034] [ka]

[0035] (In the formula, R is either absent, represents an alkylene group with 1 to 6 carbon atoms, -S-, or -SO2-, and n represents an integer of 1 or greater.) The flame-retardant polyphenylene ether of the present invention has excellent solubility in solvents, and preferably has a number-average molecular weight of 1,000 to 10,000, more preferably 1,000 to 8,000, and even more preferably 1,000 to 5,000, in terms of standard polystyrene equivalent as measured by gel permeation chromatography.

[0036] The flame-retardant polyphenylene ether of the present invention has excellent solubility in solvents, and its weight-average molecular weight (M) in terms of standard polystyrene, as measured by gel permeation chromatography, is superior. w ) and number-average molecular weight (M n ) ratio (M w / M n The value of ) is preferably 1.0 to 4.0, more preferably 1.2 to 3.0, and even more preferably 1.5 to 2.5.

[0037] The flame-retardant polyphenylene ether of the present invention preferably has a bromine content of 5 to 30% by weight, and more preferably 7 to 20% by weight, in order to achieve high flame retardancy.

[0038] In the present invention, the flame-retardant polyphenylene ether having the structure of general formula (1) can be produced, for example, using a polyfunctional polyphenylene ether represented by general formula (2) as a raw material. The polyfunctional polyphenylene ether represented by general formula (2) is not particularly limited, but as an example, it can be produced by reacting a compound represented by the following general formula (4) with a polyphenylene ether having repeating units represented by the following general formula (5) and a number-average molecular weight of 5,000 to 30,000 in the presence of a radical initiator and a solvent.

[0039] [ka]

[0040] (In the formula, R is either absent or represents an alkylene group having 1 to 6 carbon atoms, -S-, or -SO2-, R 1 ~R 4 Each of these independently represents a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, and an alkenyl group with 2 to 6 carbon atoms, where n is an integer greater than or equal to 1.

[0041] [ka]

[0042] (In the formula, R is either absent or represents an alkylene group with 1 to 6 carbon atoms, -S-, or -SO2-.)

[0043] [ka]

[0044] (In the formula, R 5 ~R 8Each of these independently represents a hydrogen atom, a C1-C6 alkyl group, or a C2-C6 alkenyl group. The compound represented by general formula (4) is not particularly limited, but examples include tetrabromobisphenol A, tetrabromobisphenol F, or bis(4'-hydroxy-3',5'-dibromophenyl)sulfone. Of these, tetrabromobisphenol A is particularly preferred due to its excellent heat resistance and dielectric properties.

[0045] In a polyphenylene ether having repeating units represented by general formula (5), R 5 ~R 8 The alkyl group having 1 to 6 carbon atoms represented by is not particularly limited, but examples include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, t-butyl group, n-pentyl group, n-hexyl group, etc., with methyl group being preferred among them.

[0046] In a polyphenylene ether having repeating units represented by general formula (5), R 5 ~R 8 The alkenyl group having 2 to 6 carbon atoms represented by is not particularly limited, but examples include vinyl group, allyl group, iso-propenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-pentenyl group, 1-hexenyl group, etc.

[0047] One embodiment of a polyphenylene ether having repeating units represented by general formula (5) is, for example, a compound having repeating units represented by formula (6).

[0048] [ka]

[0049] In polyphenylene ethers having repeating units represented by general formula (5), the number-average molecular weight in terms of standard polystyrene, as measured by gel permeation chromatography, is preferably 5,000 to 30,000, and more preferably 5,000 to 20,000.

[0050] In the production of polyfunctional polyphenylene ethers represented by general formula (2), the radical initiator is not particularly limited, but examples include peroxides (especially organic peroxides). Specifically, for example, dilauroyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate Examples include t-hexyl peroxybenzoate, cumene hydroperoxide, t-butyl peroxyacetate, 2,2-di(t-butylperoxy)butane, t-butyl peroxybenzoate, di-t-butyl peroxide, n-butyl 4,4-di-(t-butylperoxy)valerate, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyn-3, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, and t-butyl hydroperoxide. In particular, t-butylperoxy-2-ethylhexanoate and t-butylperoxy-2-ethylhexyl monocarbonate are preferred because they yield flame-retardant polyphenylene ethers with low molecular weight and high bromine content.

[0051] In the production of polyfunctional polyphenylene ethers represented by general formula (2), the solvent is not particularly limited as long as it does not react with the substrate. Examples include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane; alcoholic solvents such as methanol, ethanol, n-propanol, iso-propanol, and butanol; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, methyl butyl ketone, and methyl isobutyl ketone; and etheric solvents such as tetrahydrofuran and dioxane. These solvents may be used individually or in mixtures of two or more.

[0052] In the production of the polyfunctional polyphenylene ether represented by general formula (2), the reaction temperature is not particularly limited, but is preferably in the range of 40°C to 160°C, and more preferably in the range of 50°C to 150°C.

[0053] In the production of a polyfunctional polyphenylene ether represented by general formula (2), the mixing ratio of the compound represented by general formula (4) and the compound represented by general formula (5) is preferably 1 to 200 parts by weight, more preferably 5 to 150 parts by weight, and even more preferably 10 to 100 parts by weight of the compound represented by general formula (4) per 100 parts by weight of the compound represented by general formula (5).

[0054] In the production of a polyfunctional polyphenylene ether represented by general formula (2), the amount of radical initiator used is preferably 0.1 to 100 parts by weight, more preferably 1 to 80 parts by weight, and more preferably 2 to 50 parts by weight, per 100 parts by weight of the compound represented by general formula (5).

[0055] In the production of the polyfunctional polyphenylene ether represented by general formula (2), the amount of solvent used is preferably 100 to 2,000 parts by weight, more preferably 150 to 1,500 parts by weight, and even more preferably 200 to 1,000 parts by weight, per 100 parts by weight of the compound represented by general formula (5).

[0056] In the production of the polyfunctional polyphenylene ether represented by general formula (2), after the reaction is complete, the obtained polyfunctional polyphenylene ether is recovered by any method and post-treatment such as washing is performed as necessary. Known methods such as concentration and reprecipitation can be used to recover the polyfunctional polyphenylene ether from the reaction solution.

[0057] In the present invention, the method for producing a flame-retardant polyphenylene ether having the structure of general formula (1) is not particularly limited, but for example, it can be obtained by reacting a polyfunctional polyphenylene ether represented by general formula (2) in the presence of (meth)acrylic anhydride, an esterification catalyst, and a solvent.

[0058] In the production of flame-retardant polyphenylene ether represented by general formula (1), the esterification catalyst is not particularly limited, but examples include pyridine, lutidine, 4-dimethylaminopyridine, triethylamine, and diisopropylethylamine. Among these, 4-dimethylaminopyridine is preferred.

[0059] In the production of flame-retardant polyphenylene ether represented by general formula (1), the solvent is not particularly limited as long as it does not react with the substrate. Examples include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; halogenated hydrocarbon solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane; and ether solvents such as diethyl ether, tetrahydrofuran, and dioxane. These solvents may be used individually or in mixtures of two or more.

[0060] Furthermore, a flame-retardant polyphenylene ether having the structure of general formula (1) can be obtained, for example, by reacting a polyfunctional polyphenylene ether represented by general formula (2) in the presence of (meth)acrylate halide, a base, and a solvent. In this case, an esterification catalyst may be added as needed.

[0061] In the production of flame-retardant polyphenylene ether represented by general formula (1), examples of (meth)acrylic acid halides include acrylate chloride and methacrylate chloride.

[0062] In the production of flame-retardant polyphenylene ether represented by general formula (1), the base is not particularly limited, but examples include pyridine, triethylamine, diisopropylethylamine, N,N-dimethylaniline, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc.

[0063] In the production of a flame-retardant polyphenylene ether represented by general formula (1), the mixing ratio of the polyfunctional polyphenylene ether represented by general formula (2) and (meth)acrylic anhydride is preferably 1 to 100 parts by weight, more preferably 1 to 80 parts by weight, and even more preferably 5 to 40 parts by weight of (meth)acrylic anhydride per 100 parts by weight of the polyfunctional polyphenylene ether represented by general formula (2).

[0064] In the production of a flame-retardant polyphenylene ether represented by general formula (1), the mixing ratio of the polyfunctional polyphenylene ether represented by general formula (2) and the esterification catalyst is preferably 0.01 to 50 parts by weight, more preferably 0.1 to 20 parts by weight, and even more preferably 0.1 to 10 parts by weight of the esterification catalyst per 100 parts by weight of the polyfunctional polyphenylene ether represented by general formula (2).

[0065] In the production of a flame-retardant polyphenylene ether represented by general formula (1), the mixing ratio of the polyfunctional polyphenylene ether represented by general formula (2) and the base is preferably 1 to 100 parts by weight of the base, more preferably 1 to 80 parts by weight, and even more preferably 5 to 40 parts by weight, per 100 parts by weight of the polyfunctional polyphenylene ether represented by general formula (2).

[0066] In the production of the flame-retardant polyphenylene ether represented by general formula (1), the amount of solvent used is preferably 100 to 2,000 parts by weight, more preferably 150 to 1,500 parts by weight, and even more preferably 200 to 1,000 parts by weight, per 100 parts by weight of the compound represented by general formula (5).

[0067] In the production of flame-retardant polyphenylene ether represented by general formula (1), after the reaction is complete, the obtained flame-retardant polyphenylene ether is recovered by any method and post-treatment such as washing is performed as necessary. Known methods such as concentration and reprecipitation can be used to recover the flame-retardant polyphenylene ether from the reaction solution.

[0068] The flame-retardant polyphenylene ether resin composition of the present invention is characterized by containing the flame-retardant polyphenylene ether of the present invention described above, and may also contain other components such as a crosslinking agent, a thermal polymerization initiator, a solvent, or an inorganic filler.

[0069] The crosslinking agent is not particularly limited as long as it is a compound having a carbon-carbon unsaturated double bond, but examples include allyl compounds such as triallyl isocyanurate, triallyl cyanurate, diallyl monoalkyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, and triallyl trimellitate, and bis(m-vinylphenyl)ethane, 1,2-bis(p-vinylphenyl)ethane, and 1-(p-vinylphenyl)-2-bis(m-vinylphenyl)ethane. Examples include vinylphenylmethanes, polyfunctional methacrylate compounds having two or more methacrylic groups in the molecule, polyfunctional acrylate compounds having two or more acrylic groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene, vinylbenzyl compounds such as divinylbenzene having a vinylbenzyl group in the molecule, polyfunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimidediphenylmethane, and divinylbenzene polymers having vinyl groups in the side chain.

[0070] When a crosslinking agent is included, the weight ratio of flame-retardant polyphenylene ether to the crosslinking agent is preferably 25:75 to 95:5, and more preferably 30:70 to 90:10.

[0071] The thermal polymerization initiator is not particularly limited as long as it is a compound that can generate radicals upon heating, but organic peroxides are preferred. Examples include t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxybenzoate, di(2-t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butyl peroxyisophthalate, t-butylcumyl peroxide, cumene hydroperoxide, cumyl peroxyneodecanoate, di-(3-methylbenzoyl) peroxide, benzoyl(3-methylbenzoyl) peroxide, dibenzoyl peroxide, n-butyl 4,4-di-(t-butylperoxy)valerate, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and di-t-butyl peroxide.

[0072] The content of the thermal polymerization initiator is preferably 0.05 to 5 parts by weight, and more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total of the flame-retardant polyphenylene ether and the crosslinking agent.

[0073] The solvent is preferably a good solvent for the flame-retardant polyphenylene ether of the present invention, and is not particularly limited as long as it does not inhibit the curing reaction. Examples include aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone, and halogenated hydrocarbon solvents such as chloroform. These solvents may be used individually or in mixtures of two or more.

[0074] Inorganic fillers are not particularly limited, but examples include metal oxides, nitrides, silicides, and borides such as silica, boron nitride, talc, alumina, zirconia, and titania.

[0075] The cured product of the present invention is obtained by curing the flame-retardant polyphenylene ether resin composition of the present invention by heating or hot pressing in the presence of a thermal polymerization initiator. The temperature conditions during hot pressing are not particularly limited as long as they allow curing by a thermal polymerization reaction based on the thermal polymerization initiator. For example, such conditions include a temperature of 150 to 230°C.

[0076] The flame-retardant polyphenylene ether resin composition of the present invention can be used as a resin composition for forming an insulating layer on circuit boards such as printed circuit boards. In particular, by taking advantage of the benefit of being able to obtain an insulating layer with low dielectric constant and dielectric loss tangent, it can be suitably used as a resin composition for forming an insulating layer on high-frequency circuit boards.

[0077] The flame-retardant polyphenylene ether resin composition of the present invention can be impregnated into various organic or inorganic cloths or nonwoven fabrics, dried, and used as a prepreg, which is a substrate material. Examples of inorganic cloths or nonwoven fabrics include glass cloth or glass nonwoven fabric. Furthermore, by layering the prepreg with a conductive foil such as copper foil and heat-pressing it, a laminate having a conductive foil on its surface can be created. [Examples]

[0078] The present invention will be described in more detail below based on examples, but the present invention is not limited in any way to these examples.

[0079] Number-average molecular weight (M) determined by gel permeation chromatography (GPC) n ) and weight-average molecular weight (M w ) measurement> Equipment: HLC-8320GPC manufactured by Tosoh Corporation Columns: Connect TSKgel SuperAW2500, SuperAW3000, and SuperAW5000 manufactured by Tosoh Corporation. Eluent: Tetrahydrofuran Flow rate: 0.6mL / min Column temperature: 40℃ Detector: UV (254nm) Calibration curve: A calibration curve was obtained using the following standard substances (all standard polystyrenes manufactured by Tosoh Corporation). · "A-500" (weight-average molecular weight = 589) · "A-1000" (weight-average molecular weight = 1,120) · "A-2500" (weight-average molecular weight = 3,120) · "A-5000" (weight-average molecular weight = 5,520) · "F-1" (weight-average molecular weight = 8,840) · "F-2" (weight-average molecular weight = 15,700) · "F-4" (weight-average molecular weight = 37,200) · "F-10" (weight-average molecular weight = 110,000) · "F-20" (weight-average molecular weight = 225,000) <Measurement of bromine content by combustion-ion chromatography> Combustion apparatus: AQF-2100H manufactured by Mitsubishi Chemical Analytech Co., Ltd. Sample amount: 4 mg Combustion temperature: 900 °C on the inlet side and 1000 °C on the outlet side Absorbent solution composition: 30 mg / L hydrogen peroxide solution Absorbent solution amount: 30 mL Ion chromatograph: IC-2010 manufactured by Tosoh Corporation Eluent: 7.5 mmol / L sodium hydrogen carbonate aqueous solution + 0.8 mmol / L sodium carbonate aqueous solution Detection: Electrical conductivity Analysis column: TSKgel SuperIC-Anion HS Guard column: TSKguardcolumn SuperIC-A HS Column temperature: 40 °C Injection volume: 30 μL Flow rate: 1.5 mL / min Suppressor gel: TSKgel suppress IC-A< <Structural analysis by NMR> Apparatus: JNM-EC 400YH manufactured by JEOL Ltd. Solvent: 1,1,2,2-tetrachloroethane-d2 In the flame-retardant polyphenylene ether represented by the general formula (1), the hydrogen on the brominated aromatic ring 1 The 1H NMR peak is observed around 7.44 ppm and around 7.41 ppm.

[0080] <Structural analysis by FTIR> Apparatus: Frontier FTIR manufactured by PerkinElmer Japan Co., Ltd. Solvent: 1,1,2,2-tetrachloroethane-d2 In the flame-retardant polyphenylene ether represented by the general formula (1), the peak derived from the C=O stretching vibration of the (meth)acrylic group, which is a functional group showing crosslinkability by radical reaction, is at 1737 cm -1 It is observed around.

[0081] <Measurement of glass transition temperature by differential scanning calorimetry (DSC)> Apparatus: DSC 200 F3 manufactured by NETZSCH Japan Co., Ltd. Measurement conditions: Under a nitrogen atmosphere, the temperature was raised to 250 °C at a rate of 10 °C / min, then cooled to 25 °C at a rate of 40 °C / min, and then the temperature was raised to 250 °C at a rate of 10 °C / min to measure the glass transition temperature (T g ).

[0082] <Evaluation of solubility in toluene> 0.10 g of the flame-retardant polyphenylene ether and 0.90 g of toluene were put into a 9 mL glass screw tube (10% by weight), and mixed for 30 minutes at 20 °C using a stir bar and a magnetic stirrer. After standing for 24 hours, if the solution remained transparent, it was judged as "〇", and if it became opaque or the presence of insoluble matter was confirmed, it was judged as "×".

[0083] <Synthesis of polyfunctional polyphenylene ether> Synthesis Example 1 Into a 1 L four-necked eggplant flask equipped with a magnetic stir bar and a reflux condenser, 500 g of toluene (manufactured by Kishida Chemical Co., Ltd.), 100 g of poly(2,6-dimethyl-1,4-phenylene ether) (manufactured by BLD Pharmatech LTD, M n(=17,000), 80.0 g of tetrabromobisphenol A (manufactured by Tosoh Corporation, 0.147 mol) was added, and the mixture was heated to 90°C while stirring. At this temperature, a solution of 20.0 g of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, product name Perbutyl O, 92.5 mmol) dissolved in 100 g of toluene was added dropwise over 30 minutes. After the addition was complete, the mixture was stirred at 90°C for 3 hours and then allowed to cool to room temperature. The resulting reaction mixture was added to methanol (manufactured by Kishida Chemical Co., Ltd.), the precipitated solid was filtered, washed with methanol, and then dried. A white solid polyfunctional polyphenylene ether (a) was obtained in a yield of 129.7 g.

[0084] The analysis results of the product are shown below. 1 H NMR (400MHz, tetrachloroethane-d2, ppm) δ=7.42(Ar-H),7.29(Ar-H),6.56(Ar-H),6.47(Ar-H),2.24-1.99(C H 3), 1.69-1.65(C H 3) M n =3,500,M w =6,800,M w / M n =1.9 Bromine content = 12.1% by weight Synthesis Example 2 In Synthesis Example 1, 100g of poly(2,6-dimethyl-1,4-phenylene ether) (BLD Pharmatech, M) was used. n (=17,000) is replaced with poly(2,6-dimethyl-1,4-phenylene ether) 100g (SABIC, product name NORYL640-111, M n Except for using (=17,000), the same procedure as in Synthesis Example 1 was carried out to obtain a white solid polyfunctional polyphenylene ether (b) in a yield of 134.2 g.

[0085] The analysis results of the product are shown below. 1H NMR (400MHz, tetrachloroethane-d2, ppm) δ=7.42(Ar-H),7.29(Ar-H),6.56(Ar-H),6.47(Ar-H),2.36-1.99(C H 3), 1.69-1.65(C H 3) M n =3,400,M w =7,300,M w / M n =2.1 Bromine content = 13.0% by weight <Synthesis of flame-retardant polyphenylene ethers> Example 1 In a 50 mL three-necked round-bottom flask equipped with a magnetic stirring bar and reflux condenser, 20 g of toluene (manufactured by Kishida Chemical Co., Ltd.), 5.00 g of polyfunctional polyphenylene ether (a), and 0.25 g of 4-dimethylaminopyridine (manufactured by Tokyo Chemical Industry Co., Ltd., 2.0 mmol) were added, and the mixture was heated to 80°C while stirring. At this temperature, 1.00 g of methacrylic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd., 6.49 mmol) was added dropwise. After the addition was complete, the mixture was stirred at 80°C for 8 hours and then allowed to cool to room temperature. The resulting reaction mixture was added to methanol (manufactured by Kishida Chemical Co., Ltd.), the precipitated solid was filtered, washed with methanol, and then dried. A white solid flame-retardant polyphenylene ether (A) was obtained in a yield of 3.7 g.

[0086] The analysis results of the product are shown below. 1 H NMR(400MHz,tetrachloroethane-d2,ppm)δ=7.44(Ar-H),7.41(Ar-H),6.65-6.45(Ar-H)6.44(C(CH3)=C H 2), 5.87(C(CH3)=C H 2), 5.77(C(CH3)=C H 2), 2.36-1.90(C H 3), 1.78-1.69(C H 3) FTIR(cm -1):ν=2924,1737,1603,1470,1380,1305,1186,1114,1096,1020,959,856,831,744 M n =4,100,M w =7,800,M w / M n =1.9 Bromine content = 9.8% by weight Example 2 In Example 1, the same procedure was carried out except that polyfunctional polyphenylene ether (b) was used instead of polyfunctional polyphenylene ether (a), and a white solid flame-retardant polyphenylene ether (B) was obtained in a yield of 3.7 g.

[0087] The analysis results of the product are shown below. 1 H NMR(400MHz,tetrachloroethane-d2,ppm)δ=7.44(Ar-H),7.41(Ar-H),6.65-6.45(Ar-H)6.44(C(CH3)=C H 2), 5.87(C(CH3)=C H 2), 5.77(C(CH3)=C H 2), 2.36-1.94(C H 3), 1.78-1.69(C H 3) FTIR(cm -1 ):ν=2924,1737,1603,1470,1379,1305,1186,1115,1096,1020,959,856,831,744 M n =4,200,M w =7,400,M w / M n = 1.8 Bromine content = 10.2% by weight T g = 165℃ Comparative Example 1 Polyphenylene ethers were synthesized according to the method of Example 1 described in Patent Document 1 (Japanese Unexamined Patent Publication No. 51-600), and a brown solid product (D) was obtained in a yield of 91%.

[0088] The analysis results of the product are shown below. M n =27,000,M w =51,000,M w / M n =1.9 Bromine content = 4.9% by weight T g =200℃ Comparative Example 2 Polyphenylene ethers were synthesized according to the method of Example 4 described in Japanese Patent Publication No. 51-8398, and a white solid product (E) was obtained in a yield of 70%.

[0089] The analysis results of the product are shown below. M n =16,000,M w =39,000,M w / M n =2.4 Bromine content = 0.8% by weight The results obtained are shown in Table 1.

[0090] [Table 1]

[0091] <Preparation of hardened material> Equipment: Manual hydraulic vacuum heating press 11FD manufactured by Imoto Seisakusho Co., Ltd. <Evaluation of flame retardancy of cured materials> Oxygen index measurements were performed in accordance with JIS K 7201.

[0092] <Measurement of relative permittivity and dielectric loss tangent of cured material> Equipment: TE mode cavity resonator manufactured by Keycom Co., Ltd. Vector Network Analyzer: Keysight Technologies PNA-X N5227B Measurement frequency: 28GHz <Thermomechanical analysis (TMA) of cured materials: Measurement of linear thermal expansion coefficient and glass transition temperature> Equipment: TA Instruments TMAQ400EM Probe: Tensile probe Load: 0.1N Measurement conditions: The average linear expansion coefficient was measured in the temperature range from 30°C to 170°C when the temperature was increased from room temperature to 230°C at a rate of 5°C / min (first heating), cooled back to room temperature, and then heated again to 230°C (second heating). The inflection point observed during the second heating was calculated as the glass transition temperature.

[0093] Example 3 In a 30 mL glass screw vial equipped with a magnetic stirrer, the T obtained in Example 2 was used. g 3.0 g of flame-retardant polyphenylene ether (B) at 165°C, 1.8 g of toluene, and 15 mg of perbutyl P (manufactured by NOF Corporation) were added and stirred and mixed at 80°C for 30 minutes to obtain a flame-retardant polyphenylene ether resin composition. The obtained flame-retardant polyphenylene ether resin composition was vacuum-dried overnight at 60°C in a vacuum oven, and then pressed using a press machine at 195°C and 60 kN for 2 hours to obtain cured product (A1). The T of cured product (A1) g The temperature was 182°C.

[0094] Example 4 In a 30 mL glass screw vial equipped with a magnetic stirrer, the T obtained in Example 2 was used. g 2.0 g of flame-retardant polyphenylene ether (B) at 165°C, 0.50 g of triallyl isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.88 g of toluene, and 12.5 mg of perbutyl P (manufactured by NOF Corporation) were added and stirred and mixed at 80°C for 30 minutes to obtain a flame-retardant polyphenylene ether resin composition. 3.5 g of the obtained flame-retardant polyphenylene ether resin composition was applied to a PTFE film and vacuum-dried overnight at 60°C in a vacuum oven. A metal frame (80 mm × 60 mm × 0.25 mm thick) was placed on the PTFE film and pressed using a press machine at 195°C and 60 kN for 2 hours to obtain a cured product (B1).

[0095] The analysis results of the cured material are shown below. Oxygen index value = 24.0 Relative permittivity 2.70, dielectric loss tangent 0.0043 Coefficient of linear expansion = 118 ppm / ℃ T g = 179℃ Comparative Example 3 In Example 4, the same procedure as in Example 4 was carried out, except that a conventionally known polyphenylene ether (SA9000 manufactured by SABIC) was used instead of the flame-retardant polyphenylene ether (B), to obtain a polyphenylene ether resin composition and a cured product (C).

[0096] The analysis results of the cured material are shown below. Oxygen index value = 22.5 Relative permittivity 2.61, dielectric loss tangent 0.0034 Coefficient of linear expansion = 103 ppm / ℃ T g = 197℃ The results obtained are shown in Table 2.

[0097] [Table 2]

[0098] From the above results, it can be seen that, compared to conventional polyphenylene ethers, the flame-retardant polyphenylene ether of the present invention has functional groups that exhibit crosslinking properties through radical reactions, as well as a low molecular weight, excellent solubility in solvents, and a high bromine content. Furthermore, the cured product obtained by curing the flame-retardant polyphenylene ether resin composition of the present invention exhibits a higher oxygen index value than cured products obtained by curing conventionally known polyphenylene ether resin compositions, indicating that it is a cured product with excellent flame retardancy.

Claims

1. A flame-retardant polyphenylene ether represented by the following general formula (1), wherein the number-average molecular weight in terms of standard polystyrene, as measured by gel permeation chromatography, is 1,000 to 10,000. 【Chemistry 1】 (In the formula, R is either absent, an alkylene group having 1 to 6 carbon atoms, -S-, or -SO) ２ - indicates R １ ~R ４ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and n is an integer of 1 or more.

2. The flame-retardant polyphenylene ether according to claim 1, wherein the number-average molecular weight in terms of standard polystyrene, as measured by gel permeation chromatography, is 1,000 to 5,000.

3. The flame-retardant polyphenylene ether according to claim 1 or claim 2, wherein the bromine content is 5% by weight or more.

4. The flame-retardant polyphenylene ether according to claim 1 or claim 2, wherein in general formula (1), R is a 2,2-propylene group and the bromine content is 5% by weight or more.

5. The flame-retardant polyphenylene ether according to claim 1 or claim 2, wherein its solubility in toluene at 20°C is 10% by weight or more.

6. A method for producing a flame-retardant polyphenylene ether according to claim 1 or claim 2, comprising reacting a polyfunctional polyphenylene ether represented by the following general formula (2) with (meth)acrylic anhydride or (meth)acrylic halide in the presence of a solvent. 【Chemistry 2】 (In the formula, R is either absent, an alkylene group having 1 to 6 carbon atoms, -S-, or -SO) ２ - indicates R １ ~R ４ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, and n is an integer greater than or equal to 1.

7. A flame-retardant polyphenylene ether resin composition comprising the flame-retardant polyphenylene ether described in claim 1.

8. Furthermore, the flame-retardant polyphenylene ether resin composition according to claim 7 comprises one or more components selected from the group consisting of a crosslinking agent, a thermal polymerization initiator, a solvent, and an inorganic filler.

9. A cured product obtained by curing the flame-retardant polyphenylene ether resin composition according to claim 7 or claim 8.

10. A method for producing a cured product, comprising heating or heat-pressing the flame-retardant polyphenylene ether resin composition according to claim 7 or claim 8 in the presence of a thermal polymerization initiator.

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