Allyl functionalized polyphenylene ether and its preparation method and application

Abstract

The present invention relates to the technical field of engineering plastics, and provides an allyl-functionalized polyphenylene ether and a preparation method and application thereof. The present invention mixes a dihydroxy-terminated polyphenylene ether, allyl chloride, a base, a catalyst, a polymerization inhibitor and an organic solvent for reaction to obtain an allyl-functionalized polyphenylene ether; the catalyst comprises a combination of p-toluenesulfonate, an iodide and a 1,3,2-diazaphosphole-type substance; and the organic solvent is a mixed solvent of a polar solvent and a non-polar solvent. The present invention achieves a reaction between allyl chloride and the end hydroxyl group of the dihydroxy-terminated polyphenylene ether under the synergistic action of multiple catalysts, and the obtained allyl-functionalized polyphenylene ether has a high degree of unsaturation and a high crosslinking density after curing, thereby exhibiting better performance. The allyl-functionalized polyphenylene ether prepared by the present invention is an ideal matrix resin material for high-frequency and high-speed electronic products, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering plastics, and in particular to an allyl functionalized polyphenylene ether and a preparation method and application thereof. Background Art

[0002] Polyphenylene ether resin, synthesized from 2,6-dimethylphenol via oxidative coupling and polycondensation, is a thermoplastic engineering plastic with excellent overall performance. It possesses not only outstanding mechanical properties but also excellent dielectric properties, a high glass transition temperature, and low water absorption.

[0003] However, despite its numerous advantages, polyphenylene ether resins still have some key drawbacks when used as substrates for printed circuit boards (PCBs). Current polyphenylene ether resins lack heat resistance. During the soldering process, PCB substrates must withstand high temperatures. However, the glass transition temperature of polyphenylene ether resins is slightly lower than the solder dip temperature, causing them to deform in environments above 200°C. This, in turn, affects mechanical properties and makes copper foil peeling and drilling difficult.

[0004] To improve these properties, the industry generally adopts the method of modifying polyphenylene ether. Currently, a common modification method involves copolymerizing 2,6-dimethylphenol with bisphenol compounds to synthesize dihydroxy-terminated polyphenylene ether resins. These dihydroxy-terminated polyphenylene ether resins are then further modified by reaction to develop modified polyphenylene ether resins suitable for high-frequency, high-speed electronics. However, the dihydroxy-terminated polyphenylene ether resins prepared by existing processes have few active groups, resulting in low crosslinking density and poor curing properties in the subsequently synthesized thermosetting polyphenylene ether resins. Summary of the Invention

[0005] In light of this, the present invention provides an allyl-functionalized polyphenylene ether, its preparation method, and application. The present invention utilizes multiple catalysts to achieve a reaction between allyl chloride and the terminal hydroxyl groups of a dihydroxy-terminated polyphenylene ether. The resulting allyl-functionalized polyphenylene ether has a high degree of unsaturation, and the resulting product, after crosslinking and curing, has a high degree of crosslinking, resulting in superior performance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A method for preparing an allyl-functionalized polyphenylene ether comprises the following steps:

[0008] The dihydroxy-terminated polyphenylene ether, allyl chloride, alkali, catalyst, polymerization inhibitor and organic solvent are mixed and reacted to obtain allyl-functionalized polyphenylene ether; the catalyst comprises a combination of p-toluenesulfonate, iodide and 1,3,2-diazaphosphole substances; and the organic solvent is a mixed solvent of a polar solvent and a non-polar solvent.

[0009] Preferably, the dihydroxy-terminated polyphenylene ether is obtained by polymerizing 2,6-dimethylphenol and a dihydroxy monomer; and the molar ratio of the allyl chloride to the dihydroxy-terminated polyphenylene ether is 2 to 10:1.

[0010] Preferably, the non-polar solvent is one or more of toluene, xylene, chlorobenzene and carbon tetrachloride; the polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, 4-dimethylaminopyridine, N-methylpyrrolidone and dimethyl sulfoxide; the mass ratio of the non-polar solvent to the polar solvent is 3 to 20:1;

[0011] The mass of the organic solvent is 1.5 to 3 times the total mass of the double-terminated hydroxyl polyphenylene ether, allyl chloride, alkali, catalyst and polymerization inhibitor.

[0012] Preferably, the base is one or more of alkali metal carbonate, alkali metal hydroxide and triethylamine; and the molar ratio of the base to the double-terminated hydroxyl polyphenylene ether is 2 to 10:1.

[0013] Preferably, the polymerization inhibitor is one or more of hydroquinone, p-benzoquinone, methylhydroquinone and p-hydroxyanisole; and the molar ratio of the polymerization inhibitor to the double-terminated hydroxyl polyphenylene ether is 0.02 to 1:1.

[0014] Preferably, the p-toluenesulfonate is sodium p-toluenesulfonate; the iodide is potassium iodide; and the 1,3,2-diazaphosphole substance is a compound having a structure shown in formula A;

[0015] Formula A;

[0016] The molar ratio of the p-toluenesulfonate to the dihydroxy-terminated polyphenylene ether is 0.01-0.1:1; the molar ratio of the iodide to the dihydroxy-terminated polyphenylene ether is 0.01-0.1:1; and the molar ratio of the 1,3,2-diazaphosphole substance to the dihydroxy-terminated polyphenylene ether is 0.01-0.1:1.

[0017] Preferably, the reaction temperature is 80-110° C., and the reaction is carried out under a protective atmosphere.

[0018] Preferably, after the reaction is completed, a reaction liquid is obtained, which further includes: performing solid-liquid separation on the reaction liquid to obtain a liquid portion; distilling the liquid portion to recover allyl chloride, adding the remaining solution from the distillation into a poor solvent to precipitate a solid product, and then performing solid-liquid separation and drying to obtain the allyl-functionalized polyphenylene ether.

[0019] The present invention also provides an allyl-functionalized polyphenylene ether prepared by the preparation method described in the above scheme, and the structure of the allyl-functionalized polyphenylene ether is shown in Formula I:

[0020]

[0021] Formula I;

[0022] In formula I: m and n are integers, R1, R2, R3, and R4 are allyl or H, and R1, R2, R3, and R4 are not H at the same time;

[0023] The unsaturation degree of the allyl functionalized polyphenylene ether is 1.8 to 5.4.

[0024] The present invention also provides the use of the allyl functionalized polyphenylene ether described in the above solution in electronic products.

[0025] The present invention provides a preparation method of allyl-functionalized polyphenylene ether, comprising the following steps: mixing dihydroxy-terminated polyphenylene ether, allyl chloride, a base, a catalyst, a polymerization inhibitor and an organic solvent for reaction to obtain the allyl-functionalized polyphenylene ether; the catalyst comprises a combination of p-toluenesulfonate, iodide and 1,3,2-diazaphosphole substances; and the organic solvent is a mixed solvent of a polar solvent and a non-polar solvent. The present invention uses the synergistic action of multiple catalysts to achieve a reaction between allyl chloride and the terminal hydroxyl groups of a dihydroxy-terminated polyphenylene ether. Para-toluenesulfonate and iodide activate the substitution reaction. The allyl chloride first forms an ether bond with the terminal hydroxyl groups of the polyphenylene ether molecule. Then, under the action of a 1,3,2-diazaphosphole (DAPs catalyst), the allyl chloride migrates to other positions on the benzene ring via a claisen rearrangement. The phenolic hydroxyl groups at the ends of the molecules can then react with other allyl chlorides to form ethers. This method introduces more allyl groups into the polyphenylene ether molecule, resulting in an allyl-functionalized polyphenylene ether with a higher degree of unsaturation. In subsequent use, the resulting polyphenylene ether resin, after crosslinking and curing, exhibits a higher crosslink density, thereby exhibiting superior performance. Furthermore, the preparation method provided by the present invention features mild reaction conditions, simple operating steps, low allyl chloride consumption, and high atom utilization, making it more suitable for large-scale industrial production.

[0026] The present invention also provides an allyl-functionalized polyphenylene ether prepared by the preparation method described in the above scheme. The allyl-functionalized polyphenylene ether provided by the present invention exhibits a low and stable molecular weight and a uniform molecular weight distribution, as well as a high degree of unsaturation. The cured polyphenylene ether resin has a high crosslink density and exhibits excellent thermal stability. It is an ideal matrix resin material for high-frequency, high-speed electronic products and has broad application prospects in the field of high-frequency, high-speed electronics. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing an allyl-functionalized polyphenylene ether, comprising the following steps:

[0028] The dihydroxy-terminated polyphenylene ether, allyl chloride, alkali, catalyst, polymerization inhibitor and organic solvent are mixed and reacted to obtain allyl-functionalized polyphenylene ether; the catalyst comprises a combination of p-toluenesulfonate, iodide and 1,3,2-diazaphosphole substances; and the organic solvent is a mixed solvent of a polar solvent and a non-polar solvent.

[0029] In the present invention, the dihydroxy-terminated polyphenylene ether is obtained by polymerizing 2,6-dimethylphenol and a dihydroxy monomer; the dihydroxy monomer is preferably 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane; the molar ratio of the 2,6-dimethylphenol to the dihydroxy monomer is preferably 20-25:1, specifically 23:1; the number average molecular weight of the dihydroxy-terminated polyphenylene ether is preferably 1500-12000, more preferably 1500-500, and the molecular weight distribution is preferably 1.5-2.5, more preferably 1.8-2.2; the present invention has no special requirements for the specific preparation method of the dihydroxy-terminated polyphenylene ether, and a method well known to those skilled in the art can be used.

[0030] In the present invention, the dihydroxy-terminated polyphenylene ether is used in solid form or in the form of a dihydroxy-terminated polyphenylene ether solution; the dihydroxy-terminated polyphenylene ether solution is specifically a dihydroxy-terminated polyphenylene ether solution obtained after polymerization of 2,6-dimethylphenol and a dihydroxy monomer, after post-treatment to remove the aqueous phase, and before solid precipitation; the solvent in the dihydroxy-terminated polyphenylene ether solution is preferably a non-polar solvent, and in a specific embodiment of the present invention, it can be a dihydroxy-terminated polyphenylene ether toluene solution, wherein the concentration of the dihydroxy-terminated polyphenylene ether is 42wt%. In the present invention, the molar weight of the dihydroxy-terminated polyphenylene ether is preferably calculated based on its number average molecular weight and mass.

[0031] In the present invention, the molar ratio of allyl chloride to dihydroxy-terminated polyphenylene ether is preferably 2 to 10:1, specifically 3:1, 5:1, 6:1, 8:1 or 10:1, more preferably 6:1.

[0032] In the present invention, the base is preferably one or more of alkali metal carbonates, alkali metal hydroxides and triethylamine; the alkali metal carbonate is preferably one or both of potassium carbonate and sodium carbonate; the alkali metal hydroxide is preferably one or both of potassium hydroxide and sodium hydroxide; in a specific embodiment of the present invention, the base is preferably potassium carbonate, which has a mild alkalinity and can avoid the decomposition of allyl chloride to produce impurities that are difficult to handle, thereby reducing the amount of allyl chloride used; the molar ratio of the base to the double-terminated hydroxyl polyphenylene ether is preferably 2 to 10:1, specifically 3:1, 5:1, 6:1, 8:1 or 10:1, more preferably 6:1.

[0033] In the present invention, the catalyst comprises a combination of p-toluenesulfonate, iodide, and 1,3,2-diazaphosphole (denoted as DAPs catalyst); the p-toluenesulfonate is preferably sodium p-toluenesulfonate; the iodide is preferably potassium iodide; the DAPs catalyst is preferably a compound having a structure shown in Formula A, the chemical name of the compound having a structure shown in Formula A is 2-(benzyloxy)-1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazaphosphole;

[0034] Formula A.

[0035] In the present invention, the molar ratio of the p-toluenesulfonate to the dihydroxy-terminated polyphenylene ether is preferably 0.01 to 0.1:1, specifically 0.01:1, 0.03:1, 0.05:1 or 0.1:1, more preferably 0.01:1; the molar ratio of the iodide to the dihydroxy-terminated polyphenylene ether is preferably 0.01 to 0.1:1, specifically 0.01:1, 0.03:1, 0.05:1 or 0.1:1, more preferably 0.01:1; the molar ratio of the DAPs catalyst to the dihydroxy-terminated polyphenylene ether is preferably 0.01 to 0.1:1, specifically 0.01:1, 0.03:1, 0.05:1 or 0.1:1, more preferably 0.01:1. In the present invention, the iodide and p-toluenesulfonate can activate the substitution reaction, and the DAPs catalyst can introduce an allyl group on the benzene ring through claisen rearrangement, so that the theoretical unsaturation degree of the product can reach 6.

[0036] In the present invention, the polymerization inhibitor is preferably one or more of hydroquinone, p-benzoquinone, methylhydroquinone and p-hydroxyanisole, more preferably hydroquinone; the molar ratio of the polymerization inhibitor to the double-terminated hydroxyl polyphenylene ether is preferably 0.02~1:1, more preferably 0.3:1; by adding the polymerization inhibitor, the present invention can inhibit premature crosslinking of the product.

[0037] In the present invention, the organic solvent is a mixed solvent of a polar solvent and a non-polar solvent; the non-polar solvent is preferably one or more of toluene, xylene, chlorobenzene, and carbon tetrachloride; the polar solvent is preferably one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), 4-dimethylaminopyridine (DMAP), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO); in a specific embodiment of the present invention, the organic solvent is preferably a mixed solvent of toluene and DMF; the mass ratio of the non-polar solvent to the polar solvent is preferably 3 to 20:1, more preferably 5:1; in a specific embodiment of the present invention, when the dihydroxy-terminated polyphenylene ether is used in the form of a dihydroxy-terminated polyphenylene ether solution, the amount of solvent in the dihydroxy-terminated polyphenylene ether solution is also calculated, and can be calculated based on the mass of the solvent in the dihydroxy-terminated polyphenylene ether solution and the total mass of the solvent required for the reaction. The present invention uses a mixed solvent of a polar solvent and a non-polar solvent as the reaction solvent, which can improve the solubility of the reaction raw materials and promote the reaction.

[0038] In the present invention, the mass of the organic solvent is preferably 1.5 to 3 times the total mass of the dihydroxy-terminated polyphenylene ether, allyl chloride, base, catalyst and polymerization inhibitor, and specifically can be 1.85 times.

[0039] In the present invention, the reaction temperature is preferably 80-110° C., specifically 90° C., and the reaction is preferably carried out under a protective atmosphere, preferably nitrogen; the reaction time is preferably 1-12 h, specifically 5 h; the reaction can be carried out under normal pressure or pressurized conditions, specifically, the reaction pressure is preferably 1-10 atm.

[0040] In the present invention, after the reaction is completed, a reaction liquid is obtained. The present invention preferably further comprises: subjecting the reaction liquid to solid-liquid separation (referred to as the first solid-liquid separation) to obtain a liquid portion; distilling the liquid portion to recover allyl chloride, adding the remaining solution from the distillation into a poor solvent to precipitate a solid product, and then subjecting the reaction liquid to solid-liquid separation (referred to as the second solid-liquid separation) and drying to obtain the allyl-functionalized polyphenylene ether. In the present invention, the first solid-liquid separation and the second solid-liquid separation are preferably carried out by centrifugal separation, suction filtration or pressure filtration; the distillation is preferably atmospheric distillation or reduced pressure distillation, more preferably reduced pressure distillation; the distillation temperature is preferably lower than 60°C; the poor solvent is preferably one or more of methanol, ethanol, n-propanol and tert-butanol, more preferably methanol; in a specific embodiment of the present invention, the method of adding the distillation residual solution to a poor solvent to precipitate a solid product preferably includes two-step precipitation, specifically: first, the distillation residual solution is added to a first part of the poor solvent, stirred to cause the solid to undergo a first precipitation, then the solid is allowed to settle by standing, and then the upper layer of solution is removed to obtain a residual solid; a second part of the poor solvent is added to the residual solid, stirred to undergo a second precipitation; the mass of the first part of the poor solvent is preferably 0.4 to 1.2 times the mass of the distillation residual solution, specifically 0.5 times; the mass of the second part of the poor solvent is preferably 0.5 to 2 times the mass of the residual solid, specifically 1.2 times; the drying is preferably carried out in a vacuum drying oven or a vacuum drum dryer, and after drying, allyl-functionalized polyphenylene ether powder is obtained.

[0041] The present invention also provides an allyl-functionalized polyphenylene ether prepared by the preparation method described in the above scheme, and the structure of the allyl-functionalized polyphenylene ether is shown in Formula I:

[0042]

[0043] Formula I;

[0044] In formula I, m and n are integers, R1, R2, R3, and R4 are allyl or H, and R1, R2, R3, and R4 are not H at the same time.

[0045] In the present invention, the unsaturation degree of the allyl-functionalized polyphenylene ether is 1.8-5.4; the number average molecular weight of the allyl-functionalized polyphenylene ether is preferably 3162-3351, and the molecular weight distribution is preferably 1.8-2.15.

[0046] In the present invention, the allyl-functionalized polyphenylene ether has a high crosslinking density and good thermal stability after curing; the curing method preferably comprises: heating and dissolving the allyl-functionalized polyphenylene ether in a solvent, then adding azobisisobutyronitrile to carry out a crosslinking reaction to obtain a crosslinked resin solution; coating the crosslinked resin solution on the surface of a substrate and drying it to obtain a cured allyl-functionalized polyphenylene ether; the solvent is preferably toluene and tetrahydrofuran, and the mass ratio of toluene and tetrahydrofuran is preferably 0.5-10:1, specifically 2:1; the mass ratio of the allyl-functionalized polyphenylene ether and azobisisobutyronitrile is preferably 1-40:1, specifically 20:1.5; the temperature of the crosslinking reaction is preferably 50-60°C, and the reaction time is preferably 10-120 min, specifically 30 min.

[0047] The present invention also provides the use of the allyl-functionalized polyphenylene ether described in the above scheme in electronic products; the electronic products are preferably high-frequency and high-speed electronic products; the allyl-functionalized polyphenylene ether can be used as a printed circuit board (PCB) substrate, and the printed circuit board is specifically a copper-clad laminate.

[0048] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] In the following examples, the preparation method of the double-terminated hydroxyl polyphenylene ether raw material is as follows:

[0050] The reactor had an inner diameter of 25 cm, a height of 70 cm, and a capacity of 35 L. The catalyst solution was prepared by dissolving 103.2 g of cuprous bromide (0.72 mol), 200 g of water, and 218.6 g of triethylamine (3 eq) in a beaker. Stirring was continued for 10 minutes before adding the solution to the reactor. The solution was then added to the reactor. 13.9 kg of toluene solvent, 8.43 kg of 2,6-dimethylphenol (69 mol), and 853 g of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane (3 mol) were then added. The reactor temperature was raised to maintain 50°C while stirring continuously. Oxygen was introduced into the reactor at a rate of 2.3 kg / h. The polymerization reaction lasted for 40 minutes, starting with the start of oxygen introduction. After the polymerization is completed, the heating is turned off and the oxygen supply is stopped. 4.8 kg of 10 wt% disodium EDTA aqueous solution is added to the system, and after sufficient stirring for 45 min, the system is allowed to stand for stratification. After the aqueous phase in the kettle is removed, 4.2 kg of deionized water is added to the system again, and the system is stirred and washed at high speed for 15 min at 60 ° C., and then allowed to stand for 10 min. The water in the lower layer is separated and removed to form a total of 23.2 kg of double-terminated hydroxyl polyphenylene ether toluene solution with a concentration of 40.2 wt%, which is stored for use.

[0051] 20 g of dihydroxy-terminated polyphenylene ether toluene solution was added to 80 g of methanol and stirred to precipitate a solid product. The solid was filtered and dried to obtain a dihydroxy-terminated polyphenylene ether solid. The intrinsic viscosity of the prepared dihydroxy-terminated polyphenylene ether solid sample was measured using an Ubbelohde viscometer according to the method in GB / T1632-1993, and the molecular weight and molecular weight distribution data of the polymer were calculated. The results are as follows: number average molecular weight M n =3095, molecular weight distribution 1.83; the hydroxyl value of the dihydroxy-terminated polyphenylene ether was measured by titration to be 31.2 mgKOH / g, and the average hydroxyl functionality of the dihydroxy-terminated polyphenylene ether sample was calculated to be 1.72.

[0052] Example 1

[0053] In a 2.5L reactor, 850g of 40.2wt% dihydroxylated polyphenylene ether toluene solution (0.11mol, 341.7g, M n=3095), 50.5g (6eq, 0.66mol) of allyl chloride, 3.63g of hydroquinone (0.3eq, 0.033mol), 0.34g of DAPs catalyst 2-(benzyloxy)-1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazaphosphacyclopentadiene (0.01eq, 0.0011mol), 91.1g of potassium carbonate powder (6eq, 0.66mol), 0.18g of potassium iodide (0.01eq, 0.0011mol), and 0.21g of sodium p-toluenesulfonate (0.01eq, 0.0011mol) were added. 212g of toluene and 181g of DMF were added, and the materials were stirred to thoroughly mix. The reactor was closed and the air in the reactor was replaced with nitrogen. The temperature in the reactor was raised to 90°C, and the reaction was continued with insulation and stirring for 5 hours.

[0054] After the reaction, the pressure was released and the reactor was opened. The solid salts in the material were separated by filtration. The resulting reaction solution was transferred to a distillation apparatus and distilled under reduced pressure at 50°C to remove and recover 25.3 g of the remaining allyl chloride. The remaining solution was pumped into a stirred precipitation kettle containing 0.69 kg of methanol (0.5 times the mass of the remaining solution) with thorough stirring. The solution was allowed to stand to allow the precipitated solids to settle. The supernatant was decanted, and 0.43 kg of methanol (1.2 times the mass of the solids) was added to the kettle. After stirring for 30 minutes, the precipitated white product was filtered through a suction filtration apparatus. After filtration, the wet product was dried in a vacuum drum dryer at 120°C until the volatile content was reduced to less than 0.5 wt%. 356.9 g of allyl-functionalized polyphenylene ether powder was obtained. The product was sampled and measured using an Ubbelohde viscometer. The number average molecular weight Mn of the product was 3255, and the molecular weight distribution was 1.85. The product was sampled and the unsaturation (U) was measured using the iodine titration method according to the method in GB / T 34247.1-2017. The results showed that U=3.81.

[0055] Examples 2 to 5

[0056] The same protocol as in Example 1 was used, except that the reaction vessel temperature was varied to 80°C, 70°C, 100°C, and 110°C during the reaction phase. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0057] Examples 6 to 9

[0058] The same protocol as in Example 1 was used, except that the amounts of allyl chloride added during the reaction feeding stage were varied to 67.3 g (8 eq, 0.88 mol), 84.2 g (10 eq, 1.10 mol), 42.1 g (5 eq, 0.55 mol), and 25.3 g (3 eq, 0.33 mol), respectively. Furthermore, the amounts of potassium carbonate powder added were varied to 121.5 g (8 eq, 0.88 mol), 151.8 g (10 eq, 1.10 mol), 75.9 g (5 eq, 0.55 mol), and 45.6 g (3 eq, 0.33 mol), respectively. Other reaction conditions and processing steps remained consistent with those in Example 1. The product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0059] Examples 10-12

[0060] The same protocol as in Example 1 was used, except that the base added during the reaction feeding stage was changed to 116.6 g sodium carbonate (10 eq, 1.10 mol), 37.0 g potassium hydroxide (6 eq, 0.66 mol), and 26.4 g sodium hydroxide (6 eq, 0.66 mol). Other reaction conditions and processing steps remained the same as in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0061] Example 13

[0062] The same protocol as in Example 1 was used, except that the amount of DAPs catalyst, 2-(benzyloxy)-1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazaphosphacyclopentadiene, added during the reaction feeding stage was changed to 3.4 g (0.1 eq, 0.011 mol). Other reaction conditions and processing steps remained consistent with those in Example 1. The product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0063] Example 14

[0064] The same protocol as in Example 1 was used, except that the amount of potassium iodide added during the reaction feeding stage was changed to 1.83 g (0.1 eq, 0.011 mol) and the amount of sodium p-toluenesulfonate added was changed to 2.14 g (0.1 eq, 0.011 mol). Other reaction conditions and processing steps remained the same as in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0065] Example 15

[0066] The same protocol as in Example 1 was used, with the following changes during the reaction feeding stage: 73 g of toluene solvent was added, 146 g of DMF solvent was added, and the total amount of toluene and DMF in the kettle was 1.5 times the sum of the masses of the other raw materials. Other reaction conditions and processing steps were consistent with those in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0067] Example 16

[0068] The same protocol as in Example 1 was used, with the following changes during the reaction feeding stage: 657 g of toluene solvent was added, 292 g of DMF solvent was added, and the total amount of toluene and DMF in the kettle was three times the sum of the masses of the other raw materials. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0069] Example 17

[0070] The same protocol as in Example 1 was used, with the following changes during the reaction feeding stage: 350 g of toluene solvent was added, 43 g of DMF solvent was added, and the mass ratio of toluene to DMF in the kettle was 20:1. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for data such as number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0071] Example 18

[0072] The same protocol as in Example 1 was used, with the following changes during the reaction feeding stage: 168 g of toluene solvent was added, 225 g of DMF solvent was added, and the mass ratio of toluene to DMF in the kettle was 3:1. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for data such as number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0073] Examples 19-20

[0074] The same protocol as in Example 1 was used, except that the amounts of the polymerization inhibitor hydroquinone added during the reaction feeding stage were changed to 0.24 g (0.02 eq, 0.0022 mol) and 12.1 g (1.0 eq, 0.11 mol), respectively. Other reaction conditions and processing steps remained the same as in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0075] Comparative Example 1: No DAPs catalyst added

[0076] The same protocol as in Example 1 was used, except that no DAPs catalyst was added during the reaction feeding stage. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0077] Comparative Example 2: No polymerization inhibitor added

[0078] The same protocol as in Example 1 was used, except that no polymerization inhibitor was added during the reaction feeding stage. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0079] Comparative Example 3: No sodium p-toluenesulfonate and potassium iodide added

[0080] The same protocol as in Example 1 was used, except that potassium iodide and sodium p-toluenesulfonate were not added during the reaction feeding stage. Other reaction conditions and processing steps remained consistent with those in Example 1. The prepared product was sampled and tested for number average molecular weight, molecular weight distribution, and degree of unsaturation. The test results are shown in Table 1.

[0081] Table 1 Sampling test data of the products in Examples 1 to 20 and Comparative Examples 1 to 3

[0082]

[0083] The data in Table 1 show that the allyl-functionalized polyphenylene ether prepared by the present invention exhibits a low and stable molecular weight, a uniform molecular weight distribution, and a high degree of unsaturation. Comparative Example 1, in which the DAPs catalyst was removed, resulted in a product with low unsaturation and a low degree of crosslinking after curing. Comparative Example 2, in which the polymerization inhibitor was removed, resulted in a product with a large molecular weight distribution, which resulted in poor crosslinking during curing. Reference 3, in which sodium p-toluenesulfonate and potassium iodide were removed, resulted in a very low degree of reaction.

[0084] Example 21

[0085] Take 20g of each of the allyl-functionalized polyphenylene ether solids prepared in Examples 1 to 20 and Comparative Examples 1 to 3, add them to a mixed solvent of 100g toluene and 50g tetrahydrofuran, and heat to dissolve. After heating to 50-60°C, add 1.5g of azobisisobutyronitrile and continue stirring for 30 minutes to obtain a solution with a viscosity of 70-90cP. The cross-linked polyphenylene ether solution is evenly spread on a glass plate and dried. The solidified polyphenylene ether solid is peeled off and sampled. Each group of samples is tested as follows:

[0086] The relative dielectric constant and dielectric loss factor of the material are tested according to the standard GB / T31838.6-2021;

[0087] The glass transition temperature and linear thermal expansion coefficient of the material are tested according to the standard GB / T36800.2-2018;

[0088] According to the standard GB / T 33047.1-2016, the temperature Td at which the material loses 5% of its weight by thermal decomposition is measured. 5% .

[0089] The test results are shown in Table 2:

[0090] Table 2 Test data of allyl functionalized polyphenylene ether after cross-linking and curing

[0091]

[0092] Copper-clad laminate substrates require high heat resistance, low dielectric constant and loss, a suitable linear thermal expansion coefficient, low moisture absorption, and good processability. Polyphenylene ether (PPE) is a typical engineering plastic. This resin substrate is widely used in the manufacture of advanced composite materials due to its low dielectric constant, high glass transition temperature, good dimensional stability, and low water absorption. Because allyl groups are non-polar, they have little impact on the electrical properties of PPE resins, maintaining their low dielectric constant and loss factor. The data in Table 2 show that the allyl-functionalized polyphenylene ether prepared by the present invention can undergo a curing reaction via the allyl group. After cross-linking and curing, the movement between the polyphenylene ether molecules is inhibited, the glass transition temperature of the material increases to 270°C-290°C, and the linear thermal expansion coefficient is significantly reduced, making it suitable as a matrix resin for copper-clad laminates. In Comparative Example 1, the DAPs catalyst was removed, resulting in a lower degree of unsaturation in the resulting polyphenylene ether. The cured resin has a low degree of cross-linking, a low glass transition temperature and decomposition temperature, and a high linear thermal expansion coefficient. In Comparative Example 2, the polymerization inhibitor was removed, resulting in a broader molecular weight distribution of the resulting polyphenylene ether. The cross-linked material has lower mechanical strength, a lower glass transition temperature, and is prone to softening, while also having a higher linear thermal expansion coefficient. In Comparative Example 3, sodium p-toluenesulfonate and potassium iodide were removed, resulting in a lower degree of reaction, a significantly lower glass transition temperature and decomposition temperature of the cured resin, and a significant increase in the linear thermal expansion coefficient.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an allyl-functionalized polyphenylene ether, characterized in that: The following steps are involved: The dihydroxy-terminated polyphenylene ether, allyl chloride, base, catalyst, polymerization inhibitor and organic solvent are mixed and reacted to obtain allyl-functionalized polyphenylene ether; the catalyst comprises a combination of p-toluenesulfonate, iodide and 1,3,2-diazaphosphole; the organic solvent is a mixed solvent of a polar solvent and a non-polar solvent; The p-toluenesulfonate is sodium p-toluenesulfonate; the iodide is potassium iodide; the 1,3,2-diazaphosphole substance is a compound with a structure shown in formula A; Formula A; The molar ratio of the p-toluenesulfonate to the dihydroxy-terminated polyphenylene ether is 0.01-0.1:1; the molar ratio of the iodide to the dihydroxy-terminated polyphenylene ether is 0.01-0.1:1; and the molar ratio of the 1,3,2-diazaphosphole substance to the dihydroxy-terminated polyphenylene ether is 0.01-0.1:

1.

2. The preparation method according to claim 1, characterized in that The dihydroxy-terminated polyphenylene ether is obtained by polymerizing 2,6-dimethylphenol and a dihydroxy monomer; the molar ratio of the allyl chloride to the dihydroxy-terminated polyphenylene ether is 2-10:

1.

3. The preparation method according to claim 1, characterized in that The non-polar solvent is one or more of toluene, xylene, chlorobenzene and carbon tetrachloride; the polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, 4-dimethylaminopyridine, N-methylpyrrolidone and dimethyl sulfoxide; the mass ratio of the non-polar solvent to the polar solvent is 3 to 20:1; The mass of the organic solvent is 1.5 to 3 times the total mass of the double-terminated hydroxyl polyphenylene ether, allyl chloride, alkali, catalyst and polymerization inhibitor.

4. The preparation method according to claim 1, characterized in that The base is one or more of alkali metal carbonate, alkali metal hydroxide and triethylamine; the molar ratio of the base to the double-terminated hydroxyl polyphenylene ether is 2-10:

1.

5. The preparation method according to claim 1, characterized in that The polymerization inhibitor is one or more of hydroquinone, p-benzoquinone, methylhydroquinone and p-hydroxyanisole; the molar ratio of the polymerization inhibitor to the double-terminated hydroxyl polyphenylene ether is 0.02-1:

1.

6. The preparation method according to claim 1, characterized in that The reaction temperature is 80-110° C. and the reaction is carried out under a protective atmosphere.

7. The preparation method according to claim 1, characterized in that After the reaction is completed, a reaction liquid is obtained, which further includes: performing solid-liquid separation on the reaction liquid to obtain a liquid portion; distilling the liquid portion to recover allyl chloride, adding the remaining solution from the distillation into a poor solvent to precipitate a solid product, and then performing solid-liquid separation and drying to obtain the allyl-functionalized polyphenylene ether.

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