Polyphenyl ether, prepreg containing polyphenyl ether, laminated board and printed circuit board

Abstract

The invention provides polyphenyl ether, a prepreg containing the polyphenyl ether, a laminated board and a printed circuit board, the polyphenyl ether has a structure shown in a formula (1), the polyphenyl ether has higher average hydroxyl functionality and proper molecular weight, is used as an epoxy resin curing agent, and compared with conventional double-hydroxyl-terminated polyphenyl ether, the polyphenyl ether has the advantages that the polyphenyl ether has better heat resistance and heat resistance; the epoxy resin composition formed by polyphenyl ether can provide more cross-linking sites and higher cross-linking density, so that the heat resistance of a cured product is improved, the water absorption rate is reduced, the electrical property of the cured product can be effectively improved, and the epoxy resin composition formed by polyphenyl ether can be used for preparing a laminated board.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to polyphenylene ether, a prepreg, a laminate and a printed circuit board containing the same. Background Art

[0002] As one of the five major engineering plastics, polyphenylene ether has the lightest specific gravity, the lowest water absorption rate, the smallest dielectric constant Dk and dielectric loss tangent Df, the strongest dielectric strength, and the best heat resistance. It can be widely used in the fields of electronics and automobile industry. Because of its excellent electrical properties, it can be used in the manufacture of high-frequency and high-speed copper-clad laminates. Since engineering plastic-grade polyphenylene ether has the disadvantages of high melt viscosity, poor fluidity, and difficult processing and molding, in order to adapt to the manufacturing process of traditional copper-clad laminates, it is necessary to modify the high molecular weight thermoplastic polyphenylene ether resin into a low molecular weight and solvent-soluble thermosetting resin.

[0003] The low molecular weight double-terminated hydroxyl polyphenylene ether prepared by the redistribution method of high molecular weight polyphenylene ether can be used as a curing resin for epoxy resin in the manufacture of copper clad laminates to improve the electrical properties, thermal properties and flexibility of copper clad laminates. However, the molecular weight of polyphenylene ether obtained by the redistribution method is usually bimodal because some of the molecular weight of polyphenylene ether cannot undergo redistribution reaction, resulting in poor solvent solubility and poor compatibility with epoxy resin. The low molecular weight double-terminated hydroxyl polyphenylene ether obtained by oxidative copolymerization of bisphenol monomers represented by tetramethyl bisphenol A and monophenol monomers represented by 2,6-dimethylphenol has a narrower molecular weight distribution, higher solvent solubility, and a shorter process route. However, polyphenylene ether with only hydroxyl groups at both ends of a molecular chain has a low hydroxyl functionality, fewer cross-linking sites when cured with epoxy resin, and insufficient curing. The heat resistance of the obtained resin cured product needs to be further improved, and there is still room for improvement in Dk and Df. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a polyphenylene ether, a prepreg, a laminate and a printed circuit board containing the same.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a polyphenylene ether having a structure as shown in formula (1):

[0007]

[0008] In formula (1), R 1 ~R 8 are each independently a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R 1 ~R 8When any one of them appears multiple times, they are the same or different, a, b, c and d are each independently an integer of 0 to 50 and are not 0 at the same time, and A has a structure as shown in formula (2) to (9):

[0009]

[0010] In the present invention, multiple R 1 Same or different, multiple R 2 Same or different, multiple R 3 Same or different, multiple R 4 Same or different, multiple R 5 Same or different, multiple R 6 Same or different, multiple R 7 Same or different, multiple R 8 Same or different.

[0011] Preferably, R 1 ~R 8 Each is independently a hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl, cyclopropyl, cyclopentyl, cyclohexyl or phenyl.

[0012] Preferably, the polyphenylene ether is any one of the following compounds I-IV:

[0013]

[0014]

[0015] wherein a, b, c and d are defined in the same manner as in formula (1).

[0016] Preferably, the average hydroxyl functionality of the molecular chain of the polyphenylene ether is 3-4.

[0017] Preferably, the number average molecular weight Mn of the polyphenylene ether is 1200 to 5000, for example, 1200, 1500, 1800, 2000, 2500, 2800, 3000, 3500, 4000, 4500, 4800 or 5000.

[0018] On the other hand, the present invention provides a method for preparing the polyphenylene ether as described above, the preparation method comprising the following steps:

[0019] (1) Preparation of polyphenol monomer: reacting a diketone carbonyl compound containing group A with monophenol monomer 1 to obtain a polyphenol monomer represented by formula A;

[0020] (2) Preparation of polyphenylene ether: subjecting the polyphenol monomer represented by formula A prepared in step (1) to an oxidative copolymerization reaction with the monophenol monomer 2 in the presence of oxygen to obtain the polyphenylene ether;

[0021]

[0022] Preferably, the diketone carbonyl compound containing group A in step (1) is selected from any one of 1,4-cyclohexanedione, 1,4-benzoquinone, tetrafluoro-1,4-benzoquinone, 2,3-dihydro-1,4-naphthoquinone, 1,4-naphthoquinone, 1,4-anthraquinone, 9,10-anthraquinone or octafluoro-9,10-anthraquinone, or a combination of at least two thereof.

[0023] Preferably, the molar ratio of the diketone carbonyl compound containing group A to the monophenol monomer 1 in step (1) is 1:6 to 20, for example 1:6, 1:6.5, 1:6.8, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20.

[0024] Preferably, the reaction in step (1) is carried out in the presence of a first catalyst and a co-catalyst.

[0025] Preferably, the first catalyst is selected from any one or a combination of at least two of concentrated sulfuric acid, concentrated hydrochloric acid, methanesulfonic acid, ethylsulfonic acid, 1-propanesulfonic acid, 1-butanesulfonic acid, trifluoromethylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or 2-fluorobenzenesulfonic acid.

[0026] Preferably, the co-catalyst is a mercapto-containing carboxylic acid having 2 to 6 carbon atoms, including but not limited to any one of thioglycolic acid, 3-mercaptopropionic acid, 3-mercaptopropanesulfonic acid, mercaptobutyric acid or mercaptosuccinic acid, or a combination of at least two thereof.

[0027] Preferably, the molar ratio of the diketo carbonyl compound containing group A to the first catalyst in step (1) is 1:0.05-0.15, for example, 1:0.05, 1:0.08, 1:0.1, 1:0.12, 1:0.14 or 1:0.15.

[0028] Preferably, the molar ratio of the diketone carbonyl compound containing group A to the co-catalyst in step (1) is 1:0.01 to 0.05, for example, 1:0.01, 1:0.02, 1:0.03, 1:0.04 or 1:0.05.

[0029] Preferably, the reaction temperature in step (1) is 60-120°C, for example 60°C, 80°C, 90°C, 100°C, 110°C or 120°C, and the reaction time is 4-8h, for example 4h, 5h, 6h, 7h or 8h.

[0030] Preferably, after the reaction in step (1) is completed, the first solvent is used for washing and filtration, and the filter cake is dried to obtain the polyphenol monomer represented by formula A.

[0031] Preferably, the first solvent is selected from any one of deionized water, methanol, ethanol or isopropanol, or a combination of at least two thereof.

[0032] Preferably, the monophenol monomer 1 and the monophenol monomer 2 are selected from any one or a combination of at least two of 2-methylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2-methyl-6-propylphenol, 2-methyl-6-phenylphenol or 2,6-diphenylphenol, more preferably 2,6-dimethylphenol.

[0033] Preferably, in step (2), the molar ratio of the polyphenol monomer represented by formula A to the monophenol monomer 2 is 1:4 to 35, for example, 1:4, 1:4.5, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:12, 1:14, 1:15, 1:17, 1:19, 1:20, 1:23, 1:25, 1:28, 1:30, 1:32 or 1:35, etc.

[0034] Preferably, the oxidative copolymerization reaction in step (2) is carried out in the presence of a second catalyst.

[0035] Preferably, the second catalyst is selected from copper amine complexes;

[0036] Preferably, the copper source in the copper amine complex is at least one of cupric chloride, cuprous chloride, cupric bromide, cuprous bromide, cupric chloride generated in situ from cupric oxide and concentrated hydrochloric acid, cupric bromide generated in situ from cupric oxide and hydrobromic acid, cuprous chloride generated in situ from cuprous oxide and concentrated hydrochloric acid, and cuprous bromide generated in situ from cuprous oxide and hydrobromic acid, preferably cuprous chloride, cuprous bromide, or cuprous bromide generated in situ from cuprous oxide and hydrobromic acid.

[0037] Preferably, the amine ligand in the copper amine complex is a monovalent or divalent tertiary amine or secondary amine, including but not limited to any one of N,N'-di-tert-butylethylenediamine, N,N'-diisopropylethylenediamine, tetramethylethylenediamine, tetramethyl-1,4-butanediamine, and N,N-dimethylbutylamine, or a combination of at least two thereof.

[0038] Preferably, the copper content in the second catalyst accounts for 0.05-0.3wt% (for example, 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt% or 0.3wt%) of the total mass of the polyphenol monomer and the monophenol monomer 2 shown in formula A, and the molar ratio of copper to nitrogen is 1:15-50, for example, 1:15, 1:18, 1:20, 1:25, 1:30, 1:35, 1:38, 1:40, 1:42, 1:45, 1:48 or 1:50.

[0039] Preferably, the oxidative copolymerization reaction in step (2) is carried out in a second solvent, and the second solvent is selected from any one of toluene, xylene, methanol, ethanol or isopropanol, or a combination of at least two thereof.

[0040] Preferably, the monophenol monomer 2 in step (2) is dissolved in a third solvent to form a solution, which is then added to the reaction system containing the polyphenol monomer represented by formula A.

[0041] Preferably, the third solvent is selected from any one of toluene, xylene, methanol, ethanol or isopropanol, or a combination of at least two thereof.

[0042] In the present invention, the second solvent and the third solvent may be the same or different.

[0043] Preferably, the total amount of the second solvent and the third solvent is 2 to 5 times the total mass of the polyphenol monomer and the monophenol monomer 2 shown in formula A, for example, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times or 5 times.

[0044] Preferably, the temperature of the oxidative copolymerization reaction in step (2) is 15-50°C (e.g., 15°C, 18°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C or 50°C), and the reaction time is 3-8h (e.g., 3h, 4h, 5h, 6h, 7h or 8h).

[0045] Preferably, after the oxidative copolymerization reaction in step (2) is completed, the reaction solution is washed with an aqueous solution containing a chelating agent, and the solvent in the organic phase is removed to obtain the polyphenylene ether.

[0046] Preferably, the chelating agent includes but is not limited to any one of ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid sodium salt, nitrilotriacetic acid, nitrilotriacetic acid sodium salt, diethylenetriaminepentaacetic acid, diethylenetriaminepentaacetic acid sodium salt, citric acid, citric acid sodium salt, tartaric acid, tartaric acid sodium salt, gluconic acid or gluconic acid sodium salt, or a combination of at least two thereof.

[0047] Preferably, the method for removing the solvent from the organic phase is to remove the solvent by vacuuming and reducing pressure in a dryer, or adding the organic phase containing polyphenylene ether into a polyphenylene ether insoluble solvent (such as methanol, ethanol or isopropanol) to precipitate solids, and then filtering and drying the filter cake to remove the solvent.

[0048] In the present invention, the average hydroxyl functionality of the polyphenylene ether molecular chain prepared by step (1) and step (2) is 3 to 4, and the number average molecular weight Mn is 1200 to 5000 (for example, 1200, 1500, 1800, 2000, 2500, 2800, 3000, 3500, 4000, 4500, 4800 or 5000).

[0049] In the present invention, a cyclic compound containing two ketocarbonyl groups and a monophenol monomer 1 containing one phenolic hydroxyl group and having no substitution at the para position are first used as main reactants, and a compound containing four phenolic hydroxyl groups is obtained under acid catalysis as a polyphenol monomer. Then, the polyphenol monomer and the monophenol monomer 2 having no substitution at the para position are subjected to an oxidative copolymerization reaction in the presence of oxygen to obtain polyphenylene ether.

[0050] In the process of preparing polyphenylene ether by oxidative copolymerization of the polyphenol monomer and the monophenol monomer prepared in the present invention, the oxidative copolymerization reaction can be smoothly carried out by controlling the monomer ratio, catalyst ratio and dosage, reaction temperature and other conditions, and polyphenylene ether with suitable molecular weight, narrow molecular weight distribution, low quinone by-products and higher average hydroxyl functionality can be obtained.

[0051] On the other hand, the present invention further provides a resin composition, which comprises the polyphenylene ether as described above, an electronic grade epoxy resin, a curing accelerator and a filler.

[0052] In the present invention, the polyphenylene ether is used as a curing agent. Preferably, the hydroxyl group of the polyphenylene ether is equivalent to the epoxy group of the epoxy resin; the amount of the curing accelerator is 0.5-1wt.% (for example, 0.5wt.%, 0.7wt.%, 0.9wt.% or 1wt.%) of the mass of the electronic grade epoxy resin; the amount of the filler is 20-40wt.% (for example, 20wt.%, 25wt.%, 28wt.%, 30wt.%, 35wt.%, 38wt.% or 40wt.%) of the total mass of the polyphenylene ether and the electronic grade epoxy resin.

[0053] Preferably, the electronic grade epoxy resin includes any one of o-cresol epoxy resin, dicyclopentadiene phenol epoxy resin, naphthyl epoxy resin, alicyclic epoxy resin or biphenyl crystalline epoxy resin, or a combination of at least two thereof.

[0054] Preferably, the curing accelerator includes at least one of triphenylphosphine, imidazole and derivatives thereof.

[0055] Preferably, the filler is spherical silicon powder.

[0056] On the other hand, the present invention further provides a prepreg, comprising a reinforcing material and the epoxy resin composition as described above attached to the reinforcing material after impregnation and drying.

[0057] In the present invention, the prepreg is obtained by impregnating the reinforcing material with the glue of the epoxy resin composition and drying to remove the solvent.

[0058] On the other hand, the present invention further provides a laminated board, comprising at least one prepreg as described above and a metal foil covering at least one side of the laminated prepreg.

[0059] In another aspect, the present invention further provides a printed circuit board, which comprises the prepreg material or the laminate as described above.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] The polyphenylene ether of the present invention has a higher average hydroxyl functionality and a suitable molecular weight. When used as an epoxy resin curing agent, it can provide more cross-linking sites and a higher cross-linking density compared to conventional double-terminated hydroxyl polyphenylene ethers, thereby improving the heat resistance of the cured product and reducing the water absorption rate. It can also more effectively improve the electrical properties of the cured product. The epoxy resin composition formed by the polyphenylene ether of the present invention can be used for the preparation of laminated boards. DETAILED DESCRIPTION

[0062] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0063] Preparation Example 1

[0064] Preparation of polyphenol monomer 1: Mix 112.1g 1,4-cyclohexanedione and 817.2g 2,3,6-trimethylphenol and heat until all solids are melted, then add 15g 98% concentrated sulfuric acid and 3.2g 3-mercaptopropionic acid. Under nitrogen protection, heat the mixed system to 100°C and stir for 8h. After the reaction, cool to 50°C, add 1000g of an aqueous solution containing 50% methanol to the mixed system, and stir to precipitate solids. After filtering, wash three times with 50% methanol aqueous solution, and dry in a vacuum oven at 80°C to obtain polyphenol monomer 1. Its nuclear magnetic hydrogen spectrum test data is as follows:

[0065] 1 H NMR (400MHz, CDCl3) δ6.88 (s, 4H), 4.30 (s, 4H), 2.25 (d, J = 13.5Hz, 24H), 2.19–2.06 (m, 20H).

[0066] Preparation Example 2

[0067] Preparation of polyphenol monomer 2: Mix 79.1g 1,4-naphthoquinone and 921g 2-methyl-6-phenylphenol and heat until all solids are melted, then add 10.3g p-toluenesulfonic acid and 1.4g 3-mercaptopropanesulfonic acid. Under nitrogen protection, heat the mixed system to 100°C and stir for 8h. After the reaction, cool to 50°C, add 1200g of an aqueous solution containing 50% isopropanol to the mixed system, and stir to precipitate solids. After filtering, wash three times with a 50% isopropanol aqueous solution, and dry in a vacuum oven at 80°C to obtain polyphenol monomer 2. Its nuclear magnetic hydrogen spectrum test data is as follows:

[0068] 1 H NMR (400MHz, CDCl3) δ7.49 (dd, J=8.1, 1.8Hz, 14H), 7.44–7.37 (m, 8H), 7.32–7.25 (m, 6H), 7.14 (d, J = 2.1Hz, 4H), 6.07 (s, 2H), 4.28 (s, 4H), 2.23 (d, J = 0.5Hz, 12H).

[0069] Preparation Example 3

[0070] Preparation of polyphenol monomer 3: Mix 83.3g 9,10-anthraquinone and 733.2g 2,6-dimethylphenol and heat until all solids are melted, then add 4.0g 98% concentrated sulfuric acid and 2.4g 3-mercaptobutyric acid. Under nitrogen protection, the mixed system is heated to 100°C and stirred for 8h. After the reaction is completed, cool to 50°C, add 1000g of an aqueous solution containing 60% ethanol to the mixed system, and stir to precipitate solids. After filtering, wash three times with 60% ethanol aqueous solution, and dry in a vacuum oven at 80°C to obtain polyphenol monomer 3. Its nuclear magnetic hydrogen spectrum test data is as follows:

[0071] 1 H NMR (400MHz, CDCl3) δ7.04 (dd, J=5.8, 3.3Hz, 4H), 6.92 (dd, J=5.8, 3.4Hz, 4H), 6.76 (s, 8H), 4.27 (s, 4H), 2.09 (s, 24H).

[0072] Preparation Example 4

[0073] Preparation of polyphenol monomer 4: 105.6g of octafluoro-9,10-anthraquinone and 901.2g of 2-methyl-6-propylphenol were mixed and heated until all solids melted, and then 2.3g of trifluoromethylsulfonic acid and 0.32g of 3-mercaptopropionic acid were added. Under nitrogen protection, the mixed system was heated to 100°C and stirred for 8h. After the reaction was completed, it was cooled to 50°C, and 1500g of an aqueous solution containing 60% methanol was added to the mixed system, and the solid was precipitated by stirring. After filtering, it was washed three times with a 60% methanol aqueous solution, and dried in a vacuum oven at 80°C to obtain polyphenol monomer 1. Its nuclear magnetic hydrogen spectrum test data are as follows:

[0074] 1 H NMR (400MHz, CDCl3) δ6.85 (d, J=0.6Hz, 8H), 4.25 (s, 4H), 2.58 (td, J=6.4, 1. 1Hz, 8H), 2.10 (s, 12H), 1.69 (qt, J = 7.6, 6.3Hz, 8H), 0.99 (t, J = 7.6Hz, 12H).

[0075] Example 1

[0076] Preparation of polyphenylene ether 1: 169.4g of polyphenol monomer 1 is dissolved in 340g of toluene, and then a catalyst system consisting of 0.56g of cuprous chloride and 9.75g of N,N'-di-tert-butylethylenediamine is added, and the mixture is stirred evenly to form a primer; 190.6g of 2-methyl-6-propylphenol is dissolved in 380g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 30°C for 5h. After the reaction is completed, 100g of a 5% aqueous solution of disodium ethylenediaminetetraacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 1.

[0077] Example 2

[0078] Preparation of polyphenylene ether 2: Preparation of polyphenylene ether 2: 171.8g of polyphenol monomer 2 is dissolved in a mixed solvent consisting of 600g of toluene and 360g of methanol, and then a catalyst system consisting of 2.22g of copper bromide and 8.66g of tetramethylethylenediamine is added, and the mixture is stirred evenly to form a primer; 144.2g of 2,3,6-trimethylphenol is dissolved in 300g of toluene, and oxygen is added dropwise while oxygen is introduced, and an oxidative copolymerization reaction occurs at 20°C for 7h. After the reaction is completed, 200g of a 5% aqueous solution of disodium ethylenediaminetetraacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is slowly added to 3500g of methanol to precipitate the resin solid. After filtering, the filter cake is washed with methanol, and then washed with methanol. Finally, the filter cake is dried in a vacuum oven at 60°C to obtain polyphenylene ether 2.

[0079] Example 3

[0080] Preparation of polyphenylene ether 3: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 0.33g of cuprous oxide, 2.0g of 48% hydrobromic acid and 18.62g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is introduced and added dropwise, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 3.

[0081] Example 4

[0082] Preparation of polyphenylene ether 4: 183.4g of polyphenol monomer 4 was dissolved in a mixed solvent consisting of 1230g of toluene and 1000g of isopropanol, and then a catalyst system consisting of 4.20g of copper bromide and 51.0g of tetramethylethylenediamine was added, and stirred evenly to prepare a primer; 436.6g of 2,6-dimethylphenol was dissolved in 870g of xylene, and added dropwise while passing oxygen, and an oxidative copolymerization reaction occurred at 40°C for 4h. After the reaction was completed, 1000g of 5% sodium citrate aqueous solution was added to the mixed system, and the mixture was stirred for 0.5h. After separation, the mixture was washed three times with deionized water. The water layer was separated, and the organic phase was decompressed to remove the volatile matter to obtain polyphenylene ether 4.

[0083] Example 5

[0084] Preparation of polyphenylene ether 5: 215.1g of polyphenol monomer 3 is dissolved in a mixed solvent consisting of 2000g of toluene and 506g of ethanol, and then a catalyst system consisting of 0.93g of cuprous oxide, 5.7g of 48% hydrobromic acid and 56.2g of N,N'-di-tert-butylethylenediamine is added, and the mixture is stirred evenly to form a primer; 823g of 2,6-dimethylphenol is dissolved in 1646g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 50°C for 3h. After the reaction is completed, 1000g of a 5% aqueous solution of disodium ethylenediaminetetraacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 5.

[0085] Example 6

[0086] Preparation of polyphenylene ether 6: 183.4g of polyphenol monomer 4 is dissolved in 3270g of toluene, and then a catalyst system consisting of 1.35g of copper bromide, 17.4g of tetramethylethylenediamine and 7.6g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 855.4g of 2,6-dimethylphenol is dissolved in 1700g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 15°C for 8h. After the reaction is completed, 1000g of a 5% aqueous solution of disodium ethylenediaminetetraacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 6.

[0087] Comparative Example 1

[0088] Preparation of polyphenylene ether 7: 215.1g of polyphenol monomer 3 is dissolved in 755g of toluene, and then a catalyst system consisting of 0.18g of cuprous oxide, 1.1g of 48% hydrobromic acid and 10.3g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 110g of 2,6-dimethylphenol is dissolved in 220g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of 5% trisodium nitrilotriacetic acid aqueous solution is added to the mixed system, and the mixture is stirred for 0.5h, and then washed with deionized water three times after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 7.

[0089] Comparative Example 2

[0090] Preparation of polyphenylene ether 8: 215.1g of polyphenol monomer 3 is dissolved in 2115g of toluene, and then a catalyst system consisting of 0.95g of cuprous oxide, 5.8g of 48% hydrobromic acid and 53.5g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 1466.4g of 2,6-dimethylphenol is dissolved in 2930g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 8.

[0091] Comparative Example 3

[0092] Preparation of polyphenylene ether 9: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 0.13g of cuprous oxide, 0.79g of 48% hydrobromic acid and 7.45g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 9.

[0093] Comparative Example 4

[0094] Preparation of polyphenylene ether 10: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 3.95g of cuprous oxide, 24.1g of 48% hydrobromic acid and 223.4g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for complexation for 0.5h. After separation, the mixture is washed three times with deionized water. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 10.

[0095] Comparative Example 5

[0096] Preparation of polyphenylene ether 11: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 0.33g of cuprous oxide, 2.0g of 48% hydrobromic acid and 2.32g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to prepare a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is introduced while being added dropwise, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed with deionized water three times after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 11.

[0097] Comparative Example 6

[0098] Preparation of polyphenylene ether 12: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 0.33g of cuprous oxide, 2.0g of 48% hydrobromic acid and 37.2g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 25°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 11.

[0099] Comparative Example 7

[0100] Preparation of polyphenylene ether 13: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 0.33g of cuprous oxide, 2.0g of 48% hydrobromic acid and 18.6g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to form a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 5°C for 6h. After the reaction is completed, 1000g of 5% trisodium nitrilotriacetic acid aqueous solution is added to the mixed system, and the mixture is stirred for 0.5h, and then washed with deionized water three times after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 13.

[0101] Comparative Example 8

[0102] Preparation of polyphenylene ether 14: 215.1g of polyphenol monomer 3 is dissolved in 1000g of toluene, and then a catalyst system consisting of 0.33g of cuprous oxide, 2.0g of 48% hydrobromic acid and 18.6g of N,N-dimethylbutylamine is added, and the mixture is stirred evenly to prepare a primer; 370g of 2,6-dimethylphenol is dissolved in 740g of toluene, and oxygen is added dropwise while passing it, and an oxidative copolymerization reaction occurs at 70°C for 6h. After the reaction is completed, 1000g of a 5% aqueous solution of trisodium nitrilotriacetic acid is added to the mixed system, and the mixture is stirred for 0.5h, and then washed three times with deionized water after separation. The water layer is separated, and the organic phase is decompressed to remove volatiles to obtain polyphenylene ether 14.

[0103] Analysis and testing

[0104] (1) Molecular weight and molecular weight distribution

[0105] The gel permeation chromatograph was Waters Alliance, with tetrahydrofuran as the mobile phase and polystyrene as the standard substance. The number average molecular weight Mn and polydispersity index PDI in the GPC spectra of polyphenylene ethers 1 to 14 were recorded and summarized in Table 1.

[0106] (2) Hydroxyl equivalent weight and average hydroxyl functionality

[0107] The hydroxyl equivalent weight (HEW) of polyphenylene ethers 1 to 14 was measured according to the method specified in GB / T 7383-2020. The average hydroxyl functionality = Mn / HEW.

[0108] (3) Quinone by-product content

[0109] The polyphenylene ether sample was dissolved in toluene to prepare a 1wt% solution, and its UV-visible absorption spectrum was scanned. The molar concentration c was calculated according to A=ε·c·l, and then converted into mass concentration. Where A is the absorbance value at 421nm, ε=6.5×10 4 L / (mol·cm) is the molar extinction coefficient of quinone byproducts in toluene, and l=1cm is the inner width of the cuvette.

[0110] Table 1 Physical and chemical parameters of polyphenylene ethers 1 to 14 prepared in Examples 1 to 6 and Comparative Examples 1 to 8

[0111]

[0112]

[0113] From the data in Table 1, we can see that:

[0114] (1) The polyphenylene ethers 1 to 6 prepared by the method disclosed in the present invention have a number average molecular weight of 1210 to 4970, a narrow molecular weight distribution PDI of 1.4 to 1.7, an average hydroxyl functionality of 3.80 to 3.94, which is very close to the theoretical value of 4.0, and a low content of quinone byproducts produced during the polymerization process, which is 38 to 56 ppm;

[0115] (2) Compared with the molar ratio of monophenol monomer 2: polyphenol monomer in Example 3 = 10:1, the ratio in Comparative Example 1 is 1.5:1, the ratio of catalyst Cu / total mass of monomers, the ratio of total mass of solvents / total mass of monomers and other material usage ratios remain unchanged, other reaction conditions and post-treatment conditions remain unchanged, and the number average molecular weight of the obtained polyphenylene ether 7 is significantly reduced; Compared with the molar ratio of monophenol monomer 2: polyphenol monomer in Example 2 = 40:1, other material ratios and reaction conditions remain unchanged, the number average molecular weight of the obtained polyphenylene ether 8 is significantly increased, and the average hydroxyl functionality of the molecular chain is reduced from 3.94 close to the theoretical value to 3.23; In summary, a molar ratio of monophenol monomer 2 to polyphenol monomer that is too high or too low will have an adverse effect on the key parameters of the prepared polyphenylene ether;

[0116] (3) Compared with the catalyst dosage of Cu / total monomer mass=0.05% in Example 3, the catalyst dosage in Comparative Example 3 was reduced to 0.02%, and the N / Cu molar ratio remained unchanged. Since the catalyst dosage was greatly reduced, the polymerization activity was reduced, resulting in a large number of monomers not participating in the polymerization under the same reaction conditions, the number average molecular weight of the polyphenylene ether 9 was low, the molecular weight distribution became broad, and the average hydroxyl functionality was also significantly low; in Comparative Example 4, the catalyst Cu dosage was increased to 0.6%, and the other material ratios and reaction conditions remained unchanged, and the molecular weight of the obtained polyphenylene ether 10 was small and the PDI was large; due to the excessive catalyst dosage, the high degree of self-polymerization of the monophenol monomer 2 resulted in a significantly small average hydroxyl functionality, and the content of quinone by-products was also increased; in summary, it can be seen that too high or too low a catalyst dosage will have an adverse effect on the key parameters of the prepared polyphenylene ether;

[0117] (4) Compared with the molar ratio of N element to Cu element of the catalyst component amine ligand in Example 3 = 40:1, the ratio in Example 5 is 5:1, and other conditions remain unchanged. The number average molecular weight of the polyphenylene ether 11 prepared in this way is smaller, the PDI is larger, the average hydroxyl functionality is reduced, and the content of quinone by-products is significantly increased; the molar ratio of N element to Cu element of the catalyst used in Example 6 = 80:1, and other conditions remain unchanged. The molecular weight of the polyphenylene ether 12 prepared in this way is slightly increased, and other parameters do not change much. However, due to the introduction of too much amine ligand, it is not completely removed through the same post-treatment process and remains in the product, affecting the subsequent application effect;

[0118] (5) Compared with the catalytic oxidation copolymerization reaction temperature of 25°C in Example 3, the reaction temperature in Example 7 was reduced to 5°C, and the activity and rate of the catalytic oxidation copolymerization reaction decreased, resulting in a significant decrease in the molecular weight of the prepared polyphenylene ether 13 and a significant decrease in the average hydroxyl functionality; the reaction temperature in Example 8 was increased to 70°C, and the increased reaction activity led to an increase in side reactions, and the molecular weight of the obtained polyphenylene ether 14 decreased slightly, the PDI increased significantly, the average hydroxyl functionality decreased, and the content of quinone by-products increased significantly; in summary, it can be seen that too high or too low a temperature for the catalytic oxidation copolymerization reaction will have an adverse effect on the key parameters of the prepared polyphenylene ether.

[0119] Application Examples 1 to 6 and Comparative Application Examples 1 to 8

[0120] The polyphenylene ethers 1 to 6 prepared in Examples 1 to 6 and the polyphenylene ethers 7 to 14 prepared in the comparative examples can be used as curing agents for electronic grade epoxy resins. The present invention takes the dicyclopentadiene phenol type epoxy resin HP-7200H (epoxy equivalent 282g / eq, softening point 77°C, hydrolyzable chlorine content 58ppm, from DIC Corporation of Japan) as an example to demonstrate the application effect of the polyphenylene ether disclosed in the present invention: the amount of each polyphenylene ether used as the curing agent for the epoxy resin HP-7200H is equivalent to HP-7200H (hydroxyl equivalent to epoxy equivalent 1:1); the curing accelerator used is 2-ethyl-4-methylimidazole (2E4MZ, content 99%, from MacLean reagent) as an example, and the amount is 0.5wt% of HP-7200H; the filler is spherical silica powder (D 50 The particle size is 2 μm, D 100 Particle size <10μm, from Jiangsu Shengtian New Materials Co., Ltd.), the dosage is 30wt% of the total resin.

[0121] Application Examples 1 to 6 respectively provide a resin composition, and a prepreg and a laminate prepared with the resin composition. The specific components and their amounts are shown in Table 2. In Table 2, the amount unit of each component is "parts by weight".

[0122] Table 2

[0123]

[0124] Comparative Application Examples 1 to 8 respectively provide a resin composition, and a prepreg and a laminate prepared with the resin composition. The specific components and their amounts are shown in Table 3. In Table 3, the amount unit of each component is "parts by weight".

[0125] Table 3

[0126]

[0127] Preparation of prepregs and laminates:

[0128] (1) Preparation of resin glue: According to the formulations listed in the application examples and comparative application examples in Tables 2 and 3, the components in each formulation were mixed evenly with butanone as a solvent to prepare a glue with a solid content of 60%:

[0129] (2) Preparation of prepreg: 7628 electronic grade glass fiber cloth was immersed in the resin glue obtained in step (1) for 1 min, and the residual resin glue was rolled out with a pneumatic rolling machine at a pressure of 0.5 MPa, and then baked in an explosion-proof oven at 100° C. for 10 min to remove the solvent, and then baked in an oven at 150° C. for 10 min to obtain a prepreg with a resin composition content of 50%;

[0130] (3) Laminated board: 6 sheets of prepreg obtained in step (2) are stacked, and the upper and lower sides are covered with 1 / 2 oz copper foil, and hot pressed for 2 h at a pressure of 2 MPa and a temperature of 200° C. in a vacuum hot laminator to obtain a laminated board.

[0131] Application performance testing:

[0132] (1) Glass transition temperature Tg-DMA: Measured according to the method specified in IPC-TM-650 2.4.24.4, and the temperature corresponding to the maximum value of tan is Tg-DMA.

[0133] (2) Dielectric constant Dk and dielectric loss tangent Df: Determine the Cp and D values ​​of the intermediate insulating layer material at 1 MHz after removing the copper foil according to the method specified in IPC-TM-650 2.5.5.9, and calculate Dk and Df according to the following formula:

[0134]

[0135] Among them, C p : Equivalent parallel capacitance of the insulating layer material (unit: F); D: dissipation factor (measured value); t m : average thickness of the insulating layer material (unit: m); A: surface area of ​​the protected electrode (unit: m 2 );d:diameter of the protected electrode;ε0:dielectric constant of free space 8.854×10 -12 (Unit: F / m).

[0136] (3) Water absorption: The water absorption shall be determined according to the method specified in GB / T 40564-2021 6.10.

[0137] The laminates provided by Examples 1 to 6 and Comparative Application Examples 1 to 8 were tested according to the above test method. The test results are shown in Table 4.

[0138] Table 4

[0139]

[0140] According to the data in Table 4, we can see that:

[0141] (1) The laminates provided in Examples 1 to 6 have a Tg of 225 to 256°C, a Dk of 3.7 to 4.5, a Df of only 0.0006 to 0.006, and a water absorption rate of only 0.05 to 0.23%. This indicates that the laminates made from the resin compositions composed of the polyphenylene ethers 1 to 6 prepared in Examples 1 to 6 as epoxy resin curing agents have excellent heat resistance, good electrical properties, and low water absorption.

[0142] (2) Compared with Application Example 3, the polyphenylene ether used in Comparative Application Example 1 is the polyphenylene ether 7 prepared in Comparative Example 1, and the Tg of the obtained laminate is significantly reduced, indicating that the heat resistance is reduced, and both Dk and Df are increased, indicating that the dielectric properties are deteriorated, and the water absorption rate is also significantly increased; the polyphenylene ether used in Comparative Application Example 2 is the polyphenylene ether 8 prepared in Comparative Example 2, which has a large molecular weight and a low average hydroxyl functionality, resulting in a significantly lower curing activity with the epoxy resin, and the Tg of the laminate prepared therefrom is significantly reduced, indicating that the heat resistance is reduced, and Dk and Df are also increased; In summary, the polyphenylene ether prepared with a molar ratio of monophenol monomer 2 to polyphenol monomer that is too high or too low is used in the production of laminates, which will have an adverse effect on the performance of the laminates;

[0143] (3) Compared with Application Example 3, the polyphenylene ether used in Comparative Application Example 3 is polyphenylene ether 9 prepared in Comparative Example 3, and the Tg of the obtained laminate is significantly lower, indicating that the heat resistance is significantly deteriorated, and Dk, Df and water absorption rate are also significantly increased; the polyphenylene ether used in Comparative Application Example 4 is polyphenylene ether 10 prepared in Comparative Example 4. Since the amount of copper catalyst used in the preparation of polyphenylene ether 10 is significantly larger than that of polyphenylene ether 3, the amount of amine ligand is also relatively large, resulting in incomplete removal through the same post-treatment process, and there are residues that participate in the subsequent epoxy resin curing. The Tg of the obtained laminate is relatively low, Dk and Df are significantly increased, and the water absorption rate is also increased; In summary, the polyphenylene ether prepared with too high or too low catalyst dosage used in the production of laminates will have an adverse effect on the performance of the laminates;

[0144] (4) Compared with Application Example 3, the polyphenylene ether used in Comparative Application Example 5 is polyphenylene ether 11 prepared in Comparative Example 5, and the Tg of the obtained laminate is significantly lower, while Dk, Df and water absorption rate are increased; the polyphenylene ether used in Comparative Application Example 6 is polyphenylene ether 12 prepared in Comparative Example 6, and the physical properties of polyphenylene ether 12 itself are not significantly worse than those of polyphenylene ether 3, but due to the excessive amount of amine ligands introduced during the preparation of polyphenylene ether 12, the amine ligands are not completely removed through the same post-treatment process, and there are residues that participate in the subsequent epoxy resin curing, and the Tg of the obtained laminate is significantly lower, and Dk and Df are significantly increased, and the water absorption rate is also increased; in summary, the polyphenylene ether prepared with too high or too low a proportion of amine ligands in the catalyst used in the production of laminates will have an adverse effect on the performance of the laminates;

[0145] (5) Compared with Application Example 3, the polyphenylene ether used in Comparative Application Example 7 is polyphenylene ether 13 prepared in Comparative Example 7, and the Tg of the obtained laminate is significantly lower, indicating that the heat resistance is significantly deteriorated, and Dk, Df and water absorption are also significantly increased; the polyphenylene ether used in Comparative Application Example 8 is polyphenylene ether 14 prepared in Comparative Example 8, and the Tg of the obtained laminate is also significantly decreased, and Dk, Df and water absorption are also increased; In summary, the polyphenylene ether prepared by the catalytic oxidation copolymerization reaction temperature that is too high or too low is used in the production of laminates, which will have an adverse effect on the performance of the laminates.

[0146] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the polyphenylene ether, prepreg, laminate and printed circuit board containing the same, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyphenylene ether, characterized in that The polyphenylene ether has a structure as shown in formula (1): In formula (1), R 1 ~R 8 are each independently a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R 1 ~R 8 When any one of them appears multiple times, they are the same or different, a, b, c and d are each independently an integer from 0 to 50 and are not all 0, and A has a structure as shown in formulas (2) to (9):

2. The polyphenylene ether according to claim 1, characterized in that R 1 ~R 8 Each is independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group or a phenyl group.

3. The polyphenylene ether according to claim 1 or 2, characterized in that The polyphenylene ether is any one of the following compounds I-IV: wherein a, b, c and d are defined in the same manner as in formula (1); Preferably, the average hydroxyl functionality of the molecular chain of the polyphenylene ether is 3 to 4; Preferably, the number average molecular weight Mn of the polyphenylene ether is 1200-5000.

4. The method for preparing polyphenylene ether according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) Preparation of polyphenol monomer: reacting a diketone carbonyl compound containing group A with a monophenol monomer 1 to obtain a polyphenol monomer represented by formula A; (2) Preparation of polyphenylene ether: subjecting the polyphenol monomer represented by formula A prepared in step (1) to an oxidative copolymerization reaction with the monophenol monomer 2 in the presence of oxygen to obtain the polyphenylene ether; 5. The preparation method according to claim 4, characterized in that The diketone carbonyl compound containing group A in step (1) is selected from any one or a combination of at least two of 1,4-cyclohexanedione, 1,4-benzoquinone, tetrafluoro-1,4-benzoquinone, 2,3-dihydro-1,4-naphthoquinone, 1,4-naphthoquinone, 1,4-anthraquinone, 9,10-anthraquinone or octafluoro-9,10-anthraquinone; Preferably, the molar ratio of the diketone carbonyl compound containing group A to the monophenol monomer 1 in step (1) is 1:6 to 20; Preferably, the reaction in step (1) is carried out in the presence of a first catalyst and a co-catalyst; Preferably, the first catalyst is selected from any one or a combination of at least two of concentrated sulfuric acid, concentrated hydrochloric acid, methanesulfonic acid, ethylsulfonic acid, 1-propanesulfonic acid, 1-butanesulfonic acid, trifluoromethylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or 2-fluorobenzenesulfonic acid; Preferably, the co-catalyst is a carboxylic acid containing a mercapto group and having a carbon number of 2 to 6; Preferably, the co-catalyst is selected from any one of mercaptoacetic acid, 3-mercaptopropionic acid, 3-mercaptopropanesulfonic acid, mercaptobutyric acid or mercaptosuccinic acid, or a combination of at least two thereof; Preferably, the molar ratio of the diketone carbonyl compound containing group A to the first catalyst in step (1) is 1:0.05-0.15; Preferably, the molar ratio of the diketone carbonyl compound containing group A to the co-catalyst in step (1) is 1:0.01 to 0.05; Preferably, the reaction temperature in step (1) is 60-120° C., and the reaction time is 4-8 h; Preferably, after the reaction in step (1) is completed, washing and filtering are performed using a first solvent, and the filter cake is dried to obtain the polyphenol monomer represented by formula A; Preferably, the first solvent is selected from any one of deionized water, methanol, ethanol or isopropanol, or a combination of at least two thereof.

6. The preparation method according to claim 4 or 5, characterized in that The monophenol monomer 1 and the monophenol monomer 2 are selected from any one or a combination of at least two of 2-methylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2-methyl-6-propylphenol, 2-methyl-6-phenylphenol or 2,6-diphenylphenol, more preferably 2,6-dimethylphenol; Preferably, in step (2), the molar ratio of the polyphenol monomer represented by formula A to the monophenol monomer 2 is 1:4 to 35; Preferably, the oxidative copolymerization reaction in step (2) is carried out in the presence of a second catalyst; Preferably, the second catalyst is selected from copper amine complexes; Preferably, the copper source in the copper amine complex is cupric chloride, cuprous chloride, cupric bromide, or cuprous bromide; preferably cuprous chloride or cuprous bromide; Preferably, the copper source in the copper amine complex is at least one of copper chloride generated in situ by copper oxide and concentrated hydrochloric acid, copper bromide generated in situ by copper oxide and hydrobromic acid, cuprous chloride generated in situ by cuprous oxide and concentrated hydrochloric acid, and cuprous bromide generated in situ by cuprous oxide and hydrobromic acid, preferably cuprous bromide generated in situ by cuprous oxide and hydrobromic acid; Preferably, the amine ligand in the copper amine complex is a monovalent or divalent tertiary amine or secondary amine; Preferably, the amine ligand in the copper amine complex is selected from any one or a combination of at least two of N,N'-di-tert-butylethylenediamine, N,N'-diisopropylethylenediamine, tetramethylethylenediamine, tetramethyl-1,4-butanediamine, and N,N-dimethylbutylamine; Preferably, the copper content in the second catalyst accounts for 0.05-0.3 wt% of the total mass of the polyphenol monomer and the monophenol monomer 2 shown in formula A, and the molar ratio of copper to nitrogen is 1:15-50; Preferably, the oxidative copolymerization reaction in step (2) is carried out in a second solvent, and the second solvent is selected from any one or a combination of at least two of toluene, xylene, methanol, ethanol or isopropanol; Preferably, the monophenol monomer 2 in step (2) is dissolved in a third solvent to form a solution, which is then added to the reaction system containing the polyphenol monomer represented by formula A; Preferably, the third solvent is selected from any one or a combination of at least two of toluene, xylene, methanol, ethanol or isopropanol; Preferably, the total amount of the second solvent and the third solvent is 2 to 5 times the total mass of the polyphenol monomer and the monophenol monomer 2 shown in formula A; Preferably, the temperature of the oxidative copolymerization reaction in step (2) is 15 to 50° C., and the reaction time is 3 to 8 hours; Preferably, after the oxidative copolymerization reaction in step (2) is completed, the reaction solution is washed with an aqueous solution containing a chelating agent to remove the solvent in the organic phase to obtain the polyphenylene ether; Preferably, the chelating agent comprises any one of ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid sodium salt, nitrilotriacetic acid, nitrilotriacetic acid sodium salt, diethylenetriaminepentaacetic acid, diethylenetriaminepentaacetic acid sodium salt, citric acid, citric acid sodium salt, tartaric acid, tartaric acid sodium salt, gluconic acid or gluconic acid sodium salt, or a combination of at least two thereof; Preferably, the method for removing the solvent from the organic phase is to remove the solvent by vacuuming and reducing pressure in a dryer, or adding the organic phase containing polyphenylene ether into a polyphenylene ether-insoluble solvent to precipitate solids, and then filtering and drying the filter cake to remove the solvent; Preferably, the average hydroxyl functionality of the polyphenylene ether molecular chain is 3 to 4; Preferably, the number average molecular weight Mn of the polyphenylene ether is 1200-5000.

7. A resin composition, characterized in that The resin composition comprises a polyphenylene ether according to any one of claims 1 to 3, an electronic grade epoxy resin, a curing accelerator and a filler; Preferably, the electronic grade epoxy resin comprises any one or a combination of at least two of o-cresol epoxy resin, dicyclopentadiene phenol epoxy resin, naphthyl epoxy resin, alicyclic epoxy resin or biphenyl crystalline epoxy resin; Preferably, the curing accelerator comprises at least one of triphenylphosphine, imidazole and derivatives thereof; Preferably, the filler is spherical silicon powder; Preferably, the hydroxyl groups of the polyphenylene ether are equivalent to the epoxy groups of the epoxy resin; Preferably, the amount of the curing accelerator is 0.5 to 1 wt.% of the mass of the electronic grade epoxy resin; Preferably, the amount of the filler is 20 to 40 wt.% of the total mass of the polyphenylene ether and the electronic-grade epoxy resin.

8. A prepreg, characterized in that The prepreg comprises a reinforcing material and the epoxy resin composition as described above which is attached to the reinforcing material after being impregnated and dried.

9. A laminated board, characterized in that: The laminate comprises at least one prepreg according to claim 8 and a metal foil covering at least one side of the laminated prepreg.

10. A printed circuit board, characterized in that: The printed circuit board comprises the prepreg according to claim 8 or the laminate according to claim 9.

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