A telechelic poly norbornene type reactive co-curing agent, its preparation method and application

Abstract

This invention discloses a telechelicerable polynorbornene reactive co-curing agent, its preparation method, and its applications. The telechelicerable polynorbornene reactive co-curing agent is a double-terminated carboxyl oligomer obtained from polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer through olefin metathesis degradation, or a hydrogenated product of the obtained double-terminated carboxyl oligomer. This invention also relates to a low-dielectric epoxy resin prepared using this co-curing agent, the raw material composition by mass parts being: 100 parts bisphenol A type epoxy resin, 64-69 parts curing agent, 5-20 parts telechelicerable polynorbornene reactive co-curing agent, and 0.8-1 parts accelerator. This invention, by introducing low-polarity alicyclic segments and involving the end groups in the construction of the curing network, can reduce the dielectric constant of the epoxy cured product while maintaining good mechanical properties, making it suitable for applications such as electronic packaging and copper-clad laminate matrix resins.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin materials technology, specifically to a telechelic polynorbornene reactive co-curing agent, its preparation method, and its application. Background Technology

[0002] With the development of mobile communication technology and high-frequency, high-speed electronic technology, higher requirements are being placed on the dielectric constant (Dk), dielectric loss (Df), moisture absorption rate, and dimensional stability of electronic packaging materials, copper-clad laminate matrix resins, and insulating materials. Bisphenol A type epoxy resins are widely used in electronic packaging, copper-clad laminates, adhesives, and composite materials due to their good adhesion, corrosion resistance, mechanical strength, and process adaptability. However, traditional epoxy resins contain many polar structures such as hydroxyl groups, ether bonds, and ester bonds after curing, which easily lead to orientation polarization and interfacial polarization under high-frequency electric fields, resulting in higher dielectric constants and dielectric losses, thus limiting their further application in high-frequency, high-speed electronics.

[0003] Existing methods for reducing the dielectric constant of epoxy resins mainly include introducing fluorinated structures, alicyclic structures, or low-polarity segments, as well as adding inorganic or organic low-dielectric fillers. While fluorinated structures can reduce the dielectric constant, the raw material cost is high, and there are limitations in compatibility and processability with conventional epoxy systems. Filler modification usually requires a high filler content, which can easily increase the viscosity of the system and introduce interfacial defects. Traditional flexible segment or rubber-based modifiers can improve toughness, but often come with trade-offs in heat resistance, modulus, or dielectric loss. Therefore, developing organic co-curing agents that combine reactivity, low polarity, and good compatibility is of great significance for obtaining epoxy resins with low dielectric properties and stable overall performance. Summary of the Invention

[0004] The purpose of this invention is to provide a telechelic polynorbornene reactive co-curing agent, its preparation method and application, which reduces the dielectric constant of the epoxy resin cured product and maintains its basic mechanical properties by introducing low polar alicyclic segments and allowing the end groups to participate in the construction of the anhydride-cured epoxy network.

[0005] In one aspect of the invention, a telechelicer type polynorbornene reactive co-curing agent is provided. According to embodiments of the invention, the telechelicer type polynorbornene reactive co-curing agent is a double-terminated carboxyl oligomer obtained from polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer through olefin metathesis degradation, or a hydrogenated product of the obtained double-terminated carboxyl oligomer.

[0006] In addition, a telechelic type polynorbornene reactive co-curing agent according to the above embodiments of the present invention may also have the following additional technical features:

[0007] In some embodiments of the present invention, the average molecular weight of the number of the di-terminated carboxyl oligomers is 500-5000 g / mol.

[0008] In another aspect, the present invention provides a method for preparing a telechelic polynorbornene reactive co-curing agent. According to an embodiment of the present invention, the method is as follows:

[0009] Teleclaw-type polynorbornene reactive co-curing agent I was obtained by degrading norbornene homopolymer with maleic acid.

[0010] Alternatively, a remote claw-type poly(norbornene-co-cyclopentene) reactive co-curing agent III obtained by degrading the copolymer of norbornene and cyclopentene with maleic acid;

[0011] Alternatively, the co-curing agent I can be hydrogenated to saturate double bonds to obtain a telechelic polynorbornene reactive co-curing agent II;

[0012] Alternatively, the co-curing agent III can be hydrogenated to saturate double bonds to obtain a telechelic polynorbornene reactive co-curing agent IV.

[0013] In addition, the preparation method of the telechelic type polynorbornene reactive co-curing agent according to the above embodiments of the present invention may also have the following additional technical features:

[0014] In some embodiments of the present invention, the preparation methods of the co-curing agent I and co-curing agent III are as follows:

[0015] Under a nitrogen atmosphere, polynorbornene homopolymer, poly(norbornene-co-cyclopentene) copolymer, maleic acid, and Grubbs2 were respectively mixed. nd The catalyst was stirred and reacted at 20-30℃ for 4-8 hours, then vinyl ether was added, and the reaction was stirred and reacted at 20-30℃ for 0.5-1 hours. Then, the mixture was rotary evaporated, extracted, and dried (vacuum drying at 20-40℃) to constant weight, to obtain telechelic polynorbornene reactive co-curing agent I and telechelic poly(norbornene-co-cyclopentene) reactive co-curing agent III, respectively.

[0016] In this context, the molar ratio of repeating units of polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer to maleic acid is (5-10):1; the molar ratio of repeating units of polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer to Grubbs2 is... nd The molar ratio of the catalyst is (1000-2000):1; the molar ratio of Grubbs2nd catalyst to vinyl ether is 1:(5-10).

[0017] In the above steps, polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer serves as the source of the low-polarity alicyclic backbone, and maleic acid acts as a metathesis degrading agent for carboxyl-containing olefins, in Grubbs2 nd Under the action of a catalyst, it undergoes cross-metathesis with the carbon-carbon double bonds in the polymer backbone, causing the polymer chain to break and introducing carboxyl groups at the chain ends; Grubbs2 nd The catalyst is used to catalyze the metathesis reaction of olefins; vinyl ether is used to terminate the catalytic activity and stabilize the reaction system. The effect of this step is to convert the polymer into a low molecular weight oligomer with well-defined end-carboxyl groups, enabling it to subsequently participate as a reactive co-curing agent in the epoxy / anhydride curing network.

[0018] The preparation principle of the co-curing agent I or co-curing agent III lies in the fact that the molecular chain of polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer contains carbon-carbon double bonds that can participate in olefin metathesis reactions, in Grubbs 2 nd Under the action of a catalyst, the carbon-carbon double bond in this compound undergoes a cross-olefin metathesis reaction with the carbon-carbon double bond in maleic acid, causing the polymer backbone to break and forming low molecular weight oligomers. Simultaneously, maleic acid structural units are introduced into the oligomer chain ends, thus obtaining a bi-terminated carboxyl telechelic polynorbornene reactive co-curing agent. This bi-terminated carboxyl structure can participate in network construction in the subsequent epoxy / anhydride curing system, giving the resulting oligomers both low-polarity alicyclic segments and reactive end-group characteristics.

[0019] In some embodiments of the present invention, the preparation methods of the polynorbornene homopolymer and poly(norbornene-co-cyclopentene) copolymer are as follows:

[0020] Norbornene, a mixture of norbornene and cyclopentene, and Grubbs2 were respectively added. nd The catalyst was stirred at 20-30℃ for 1-2 hours, vinyl ether was added, and the mixture was stirred at 20-30℃ for 0.5-1 hours. Then, the mixture was rotary evaporated, precipitated, and dried to constant weight to obtain polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer.

[0021] When norbornene and cyclopentene are copolymerized, the molar ratio of norbornene to cyclopentene is 1:(3-5); in norbornene or a mixture of norbornene and cyclopentene, the ratio of norbornene to Grubbs2... nd The molar ratio of the catalyst is (1000-2000):1; Grubbs2 ndThe molar ratio of catalyst to vinyl ethyl ether is 1:(5-10). The norbornene undergoes a redistillation step, and the cyclopentene is soaked in a molecular sieve. Specifically, the redistillation of norbornene includes the following steps: placing commercially available norbornene in a reactor, connecting a condenser, and distilling at 120℃-135℃ to obtain norbornene free of polymerization inhibitors and water.

[0022] In some embodiments of the present invention, the preparation methods of the co-curing agent II and co-curing agent IV are as follows:

[0023] Under a nitrogen atmosphere, p-toluenesulfonyl hydrazine and xylene solvent were added to co-curing agent I and co-curing agent III, respectively. After complete dissolution, tri-n-propylamine was added. The mixture was stirred, refluxed, and cooled at 130-140℃ for 4-8 hours. Then, the mixture was rotary evaporated, precipitated, and dried to constant weight to obtain co-curing agent II and co-curing agent IV, respectively.

[0024] The molar ratio of carbon-carbon double bonds to p-toluenesulfonyl hydrazine and tri-n-propylamine in co-curing agent I and co-curing agent III is 1:2:2.

[0025] In the above steps, co-curing agents I and III provide the carbon-carbon double bonds to be hydrogenated; p-toluenesulfonyl hydrazine generates diimide-type hydrogenation active species in situ under alkaline and heating conditions, which are used for selective saturation of carbon-carbon double bonds; xylene, as a high-boiling-point reaction solvent, is beneficial for maintaining the reflux reaction at 130-140℃; tri-n-propylamine, as an alkaline auxiliary agent, promotes the decomposition of p-toluenesulfonyl hydrazine and improves the hydrogenation efficiency. The effect of this step is to reduce the unsaturation of the main chain and improve the structural stability and oxidation resistance of the co-curing agents.

[0026] The preparation principle of co-curing agent II or co-curing agent IV is as follows: the molecular chain of co-curing agent I or co-curing agent III still contains carbon-carbon double bonds formed by ring-opening metathesis polymerization and metathesis degradation. In the presence of p-toluenesulfonyl hydrazine and tri-n-propylamine, hydrogenation occurs through heating and reflux, converting the carbon-carbon double bonds into saturated carbon-carbon single bonds, thereby obtaining a hydrogenated, double-carboxyl-terminated, telechelic polynorbornene reactive co-curing agent. This hydrogenation process can reduce the unsaturation of the oligomer molecular chain, improve the thermal stability and antioxidant stability of the material, and at the same time retain the chain-terminal carboxyl structure, allowing it to continue to participate in the construction of the curing network as a reactive co-curing agent in the epoxy anhydride curing system.

[0027] In another aspect of the invention, a low-dielectric epoxy resin is provided. According to an embodiment of the invention, it comprises the following components in parts by weight:

[0028] 100 parts of bisphenol A type epoxy resin;

[0029] 64-69 parts of curing agent;

[0030] 5-20 parts of the aforementioned telechelic type polynorbornene reactive co-curing agent;

[0031] Accelerator 0.8-1 part.

[0032] In addition, the low-dielectric epoxy resin according to the above embodiments of the present invention may also have the following additional technical features:

[0033] In some embodiments of the present invention, the bisphenol A type epoxy resin is E-51, the curing agent is methylhexahydrophthalic anhydride, and the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0034] In the low-dielectric epoxy resin composition, bisphenol A type epoxy resin serves as the host resin, providing epoxy groups and a network backbone after curing; methylhexahydrophthalic anhydride serves as an anhydride curing agent, reacting with epoxy groups to form an ester bond crosslinking structure; a telechelic polynorbornene reactive co-curing agent participates in the epoxy ring-opening reaction through terminal carboxyl groups, while simultaneously introducing low-polarity alicyclic segments into the cured network; 2,4,6-tris(dimethylaminomethyl)phenol serves as an accelerator, accelerating the curing of the epoxy / anhydride system and improving the degree of curing completeness.

[0035] In another aspect, the present invention provides a method for preparing a low-dielectric epoxy resin. According to an embodiment of the present invention, the method includes the following steps:

[0036] (1) Mix the remote claw type polynorbornene reactive co-curing agent with a solvent (tetrahydrofuran or toluene), then add bisphenol A type epoxy resin and curing agent, and mix evenly at 60-80℃;

[0037] (2) The solution obtained in step (1) is rotary evaporated at 20-30℃ to remove the solvent, and then an accelerator is added and mixed evenly at 60-80℃ to obtain epoxy resin prepolymer;

[0038] (3) Pour the epoxy resin prepolymer obtained in step (2) into a preheated mold, degas it in a vacuum drying oven for 0.5-1h to remove residual air bubbles, and finally put it in an oven for pre-curing at 90-100℃ for 1.5-2.5h, curing at 130-140℃ for 1.5-2.5h, and curing at 150-160℃ for 1.5-2.5h to obtain low dielectric epoxy resin.

[0039] In the above preparation process, step (1) improves the compatibility of co-curing agent with epoxy resin and acid anhydride curing agent by solvent assistance and temperature increase mixing, so that each component forms a uniform system; step (2) removes solvent and adds accelerator, which can reduce the adverse effects of residual solvent on the porosity and dielectric properties of the cured product, and avoid premature addition of accelerator leading to premature gelation of the system; in step (3), vacuum degassing is used to remove air bubbles introduced during the mixing process, and staged temperature increase curing can first achieve pre-curing and stress release at a lower temperature, and then improve the degree of crosslinking and complete curing at a higher temperature, thereby reducing air bubbles, cracking and internal stress, and improving the dimensional stability, mechanical properties and dielectric stability of the cured product.

[0040] In another aspect of the invention, an application of a telechelic polynorbornene reactive co-curing agent in reducing the dielectric constant of anhydride-cured bisphenol A type epoxy resin is proposed. In specific application, the co-curing agent is added to a bisphenol A type epoxy resin / anhydride curing system at 5-20 parts by mass, followed by uniform mixing, degassing, and staged curing to form a cured product. Its terminal carboxyl groups participate in the ring-opening reaction of the epoxy groups, allowing the co-curing agent to be chemically bonded into the three-dimensional curing network. Because polynorbornene and its copolymer segments have a low-polarity alicyclic structure, it can reduce the system's dipole polarization and polar group density, and by moderately increasing the free volume, reduce the dielectric constant and dielectric loss, while avoiding interfacial defects caused by non-reactive fillers or rubber modifiers.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] 1. The telechelic type polynorbornene reactive co-curing agent prepared in this invention contains low-polarity alicyclic segments, which helps to reduce the overall polarization of the epoxy curing system and can reduce the dielectric constant of the epoxy curing product by adding 5-20 parts by mass.

[0043] 2. The teleclaw-type polynorbornene reactive co-curing agent prepared in this invention is not a simple physical mixture, but rather forms a chemical connection with the epoxy network through the participation of end groups in the curing reaction. This helps to improve compatibility and adjust the curing network structure, thereby maintaining good mechanical properties while reducing the dielectric constant.

[0044] 3. The telechelic type polynorbornene reactive co-curing agent prepared in this invention is obtained by metathesis degradation of ring-opening metasomatic polymers. It can convert polynorbornene homopolymers or copolymers into oligomers with well-defined end groups and provides a new reactive modification component for the molecular structure regulation of low dielectric epoxy resins. Attached Figure Description

[0045] Figure 1 The above is the 1H NMR spectrum of the teleclaw-type polynorbornene reactive co-curing agent I (CTPNB) in Example 1 of this invention;

[0046] Figure 2 The infrared spectra of the remote claw-type polynorbornene reactive co-curing agents I (CTPNB) and II (HCTPNB) in Examples 1-2 of this invention are shown.

[0047] Figure 3 The above are the 1H NMR spectra of the remote claw type polynorbornene reactive co-curing agent III (CTP(NB-CP)) in Examples 3-4 of this invention;

[0048] Figure 4 The infrared spectra of the teleclaw-type polynorbornene reactive co-curing agents III (CTP(NB-CP)) and IV (HCTP(NB-CP)) in Example 4 of this invention are shown.

[0049] Figure 5 The mechanical properties of the epoxy resins prepared in Application Examples 1-4 and Comparative Example 1 of this invention are shown in the figure.

[0050] Figure 6 The dielectric constant diagrams are for the epoxy resins prepared in Application Examples 1-4 and Comparative Example 1 of this invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] The preparation method of telechelic type polynorbornene reactive co-curing agent I includes the following steps:

[0054] Step 1: Add 10 mmol norbornene to a reactor containing 20 mL of tetrahydrofuran solvent, and add 5 μmol Grubbs2. nd The catalyst was stirred at 25°C for 1 h, 50 μmol of vinyl ether was added, and the mixture was stirred at 25°C for 0.5 h. The product was then precipitated by rotary evaporation at 25°C and dried under vacuum at 30°C to constant weight to obtain polynorbornene homopolymer.

[0055] The corresponding chemical reaction formula is as follows:

[0056] ;

[0057] In the reaction formula, n = 1500-2000.

[0058] Step 2: Under a nitrogen atmosphere, add 5 mmol of the polynorbornene homopolymer obtained in Step 1 to a reactor containing 20 mL of tetrahydrofuran solvent, and add 1 mmol of maleic acid and 2.5 μmol Grubbs2. nd The catalyst was stirred at 25°C for 6 hours, then 25 μmol of vinyl ethyl ether was added, and the mixture was stirred at 25°C for 0.5 hours. The mixture was then dried under vacuum at 30°C to constant weight by rotary evaporation, extraction, and rotary evaporation to obtain teleclaw-type polynorbornene reactive co-curing agent I.

[0059] The corresponding chemical reaction formula is as follows:

[0060] ;

[0061] In the reaction formula, m = 5-10.

[0062] Figure 1 The proton NMR spectrum of polynorbornene showed proton signals related to the main chain and proton signals of the olefins after the introduction of terminal carboxyl groups, indicating that maleic acid participated in metathesis degradation and obtained oligomers with double-terminated carboxyl groups.

[0063] Example 2

[0064] The preparation method of telechelic type polynorbornene reactive co-curing agent II includes the following steps:

[0065] Step 1: Add 10 mmol norbornene to a reactor containing 20 mL of tetrahydrofuran solvent, and add 5 μmol Grubbs2. nd The catalyst was stirred at 25°C for 1 h, 50 μmol of vinyl ether was added, and the mixture was stirred at 25°C for 0.5 h. The product was then precipitated by rotary evaporation at 25°C and dried under vacuum at 30°C to constant weight to obtain polynorbornene homopolymer.

[0066] The corresponding chemical reaction formula is as follows:

[0067] ;

[0068] In the reaction formula, n = 1500-2000.

[0069] Step 2: Under a nitrogen atmosphere, add 5 mmol of the polynorbornene homopolymer obtained in Step 1 to a reactor containing 20 mL of tetrahydrofuran solvent, and add 1 mmol of maleic acid and 2.5 μmol Grubbs2. ndThe catalyst was stirred at 25°C for 6 hours, then 25 μmol of vinyl ethyl ether was added, and the mixture was stirred at 25°C for 0.5 hours. The mixture was then dried under vacuum at 30°C to constant weight by rotary evaporation, extraction, and rotary evaporation to obtain teleclaw-type polynorbornene reactive co-curing agent I.

[0070] The corresponding chemical reaction formula is as follows:

[0071] ;

[0072] In the reaction formula, m = 5-10.

[0073] Figure 1 The proton NMR spectrum of polynorbornene showed proton signals related to the main chain and proton signals of the olefins after the introduction of terminal carboxyl groups, indicating that maleic acid participated in metathesis degradation and obtained oligomers with double-terminated carboxyl groups.

[0074] Step 3: Under a nitrogen atmosphere, place the 5 mmol of the above-obtained telechelic polynorbornene reactive co-curing agent I in a reactor, add 10 mmol of toluenesulfonyl hydrazine and 40 mL of xylene solvent, and after complete dissolution, add 10 mmol of tri-n-propylamine. Stir and reflux at 135°C for 6 h, precipitate by rotary evaporation at 25°C, and vacuum dry to constant weight at 30°C to obtain telechelic polynorbornene reactive co-curing agent II.

[0075] The corresponding chemical reaction formula is as follows:

[0076] ;

[0077] In the reaction formula, m = 5-10.

[0078] Figure 2 The carbon-carbon double bond-related absorption peaks weakened before and after hydrogenation, while the carboxyl-related absorption peaks remained, indicating that the main chain unsaturation of co-curing agent I decreased and the terminal carboxyl structure was maintained after hydrogenation.

[0079] Example 3

[0080] The preparation method of telechelic type polynorbornene reactive co-curing agent III includes the following steps:

[0081] Step 1: Add a mixture of 10 mmol norbornene and 40 mmol cyclopentene to a reactor containing 20 mL of tetrahydrofuran solvent, and add 2.5 μmol Grubbs2. nd The catalyst was stirred at 25°C for 1 h, 25 μmol of vinyl ether was added, and the reaction was stirred at 25°C for 0.5 h. The product was then precipitated by rotary evaporation at 25°C and vacuum dried at 30°C to constant weight to obtain poly(norbornene-co-cyclopentene) copolymer.

[0082] The corresponding chemical reaction formula is as follows:

[0083] ;

[0084] In the reaction formula, x = 300-1200, y = 1200-2400.

[0085] Step 2: Under a nitrogen atmosphere, add 5 mmol of the poly(norbornene-co-cyclopentene) copolymer obtained in Step 1 to a reactor containing 20 mL of tetrahydrofuran solvent, and add 1 mmol of maleic acid and 2.5 μmol of Grubbs2. nd The catalyst was stirred at 25°C for 6 hours, then 25 μmol of vinyl ether was added, and the mixture was stirred at 25°C for 0.5 hours. The mixture was then dried under vacuum at 30°C to constant weight by rotary evaporation, extraction, and rotary evaporation to obtain teleclaw-type polynorbornene reactive co-curing agent III.

[0086] The corresponding chemical reaction formula is as follows:

[0087] ;

[0088] In the reaction formula, a = 1-4 and b = 4-8.

[0089] Figure 3 The proton NMR spectrum of poly(norbornene-co-cyclopentene) backbone and the proton signals of the corresponding olefin after the introduction of terminal carboxyl groups can be observed, indicating that maleic acid participates in metathesis degradation and obtains oligomers with double-terminated carboxyl groups.

[0090] Example 4

[0091] The preparation method of telechelic type polynorbornene reactive co-curing agent IV includes the following steps:

[0092] Step 1: Add a mixture of 10 mmol norbornene and 40 mmol cyclopentene to a reactor containing 20 mL of tetrahydrofuran solvent, and add 2.5 μmol Grubbs2. nd The catalyst was stirred at 25°C for 1 h, 25 μmol of vinyl ether was added, and the reaction was stirred at 25°C for 0.5 h. The product was then precipitated by rotary evaporation at 25°C and vacuum dried at 30°C to constant weight to obtain poly(norbornene-co-cyclopentene) copolymer.

[0093] The corresponding chemical reaction formula is as follows:

[0094] ;

[0095] In the reaction formula, x = 300-1200, y = 1200-2400.

[0096] Step 2: Under a nitrogen atmosphere, add 5 mmol of the poly(norbornene-co-cyclopentene) copolymer obtained in Step 1 to a reactor containing 20 mL of tetrahydrofuran solvent, and add 1 mmol of maleic acid and 2.5 μmol of Grubbs2. nd The catalyst was stirred at 25°C for 6 hours, then 25 μmol of vinyl ether was added and stirred at 25°C for 0.5 hours. The mixture was then dried under vacuum at 30°C to constant weight by rotary evaporation, extraction, and rotary evaporation to obtain teleclaw-type polynorbornene reactive co-curing agent III.

[0097] The corresponding chemical reaction formula is as follows:

[0098] ;

[0099] In the reaction formula, a = 1-4 and b = 4-8.

[0100] Figure 3 The proton NMR spectrum of poly(norbornene-co-cyclopentene) backbone and the proton signals of the corresponding olefin after the introduction of terminal carboxyl groups can be observed, indicating that maleic acid participates in metathesis degradation and obtains oligomers with double-terminated carboxyl groups.

[0101] Step 3: Under a nitrogen atmosphere, place 5 mmol of the above-obtained telechelic polynorbornene reactive co-curing agent III in a reactor, add 10 mmol of p-toluenesulfonyl hydrazine and xylene solvent, and after complete dissolution, add 10 mmol of tri-n-propylamine. Stir and reflux at 135°C for 6 hours, precipitate by rotary evaporation at 25°C, and vacuum dry to constant weight at 30°C to obtain telechelic polynorbornene reactive co-curing agent IV.

[0102] The corresponding chemical reaction formula is as follows:

[0103] ;

[0104] In the reaction formula, a = 1-4 and b = 4-8.

[0105] Figure 4 The carbon-carbon double bond-related absorption peaks weakened before and after hydrogenation, while the carboxyl-related absorption peaks remained, indicating that the main chain unsaturation of co-curing agent III decreased and the terminal carboxyl structure was maintained after hydrogenation.

[0106] Application Example 1

[0107] A method for preparing a low-dielectric epoxy resin includes the following steps:

[0108] Step 1: Add 20 parts of the telechelic type polynorbornene reactive co-curing agent I obtained in Example 1 to a reactor containing tetrahydrofuran solvent, stir magnetically until completely dissolved, then add 100 parts of bisphenol A type epoxy resin (E-51) and 64 parts of curing agent (methylhexahydrophthalic anhydride), and mix evenly at 70°C.

[0109] Step 2: Remove the solvent from the solution obtained in Step 1 by rotary evaporation at 25°C, then add 1 part of accelerator (2,4,6-tris(dimethylaminomethyl)phenol), mix evenly at 70°C to obtain epoxy resin prepolymer;

[0110] Step 3: Pour the epoxy resin prepolymer obtained in Step 2 into molds preheated to 60°C, degas in a vacuum drying oven for 30 minutes to remove residual air bubbles, and finally place in an oven for pre-curing at 95°C for 2 hours, curing at 135°C for 2 hours, and curing at 155°C for 2 hours to obtain low dielectric epoxy resin.

[0111] Application Example 2

[0112] A method for preparing a low-dielectric epoxy resin includes the following steps:

[0113] Step 1: Add 20 parts of the telechelic type polynorbornene reactive co-curing agent II prepared in Example 2 to a reactor containing tetrahydrofuran solvent, stir magnetically until completely dissolved, then add 100 parts of bisphenol A type epoxy resin (E-51) and 64 parts of curing agent (methylhexahydrophthalic anhydride), and mix evenly at 70°C.

[0114] Step 2: Remove the solvent from the solution obtained in Step 1 by rotary evaporation at 25°C, then add 1 part of accelerator (2,4,6-tris(dimethylaminomethyl)phenol), mix evenly at 70°C to obtain epoxy resin prepolymer;

[0115] Step 3: Pour the epoxy resin prepolymer obtained in Step 2 into molds preheated to 60°C, degas in a vacuum drying oven for 30 minutes to remove residual air bubbles, and finally place in an oven for pre-curing at 95°C for 2 hours, curing at 135°C for 2 hours, and curing at 155°C for 2 hours to obtain low dielectric epoxy resin.

[0116] Application Example 3

[0117] A method for preparing a low-dielectric epoxy resin includes the following steps:

[0118] Step 1: Add 20 parts of the telechelic type polynorbornene reactive co-curing agent III prepared in Example 3 to a reactor containing tetrahydrofuran solvent, stir magnetically until completely dissolved, then add 100 parts of bisphenol A type epoxy resin (E-51) and 64 parts of curing agent (methylhexahydrophthalic anhydride), and mix evenly at 70°C.

[0119] Step 2: Remove the solvent from the solution obtained in Step 1 by rotary evaporation at 25°C, then add 1 part of accelerator (2,4,6-tris(dimethylaminomethyl)phenol), mix evenly at 70°C to obtain epoxy resin prepolymer;

[0120] Step 3: Pour the epoxy resin prepolymer obtained in Step 2 into molds preheated to 60°C, degas in a vacuum drying oven for 30 minutes to remove residual air bubbles, and finally place in an oven for pre-curing at 95°C for 2 hours, curing at 135°C for 2 hours, and curing at 155°C for 2 hours to obtain low dielectric epoxy resin.

[0121] Application Example 4

[0122] A method for preparing a low-dielectric epoxy resin includes the following steps:

[0123] Step 1: Add 20 parts of the teleclaw-type polynorbornene reactive co-curing agent IV prepared in Example 4 to a reactor containing tetrahydrofuran solvent, stir magnetically until completely dissolved, then add 100 parts of bisphenol A type epoxy resin (E-51) and 64 parts of curing agent (methylhexahydrophthalic anhydride), and mix evenly at 70°C.

[0124] Step 2: Remove the solvent from the solution obtained in Step 1 by rotary evaporation at 25°C, then add 1 part of accelerator (2,4,6-tris(dimethylaminomethyl)phenol), mix evenly at 70°C to obtain epoxy resin prepolymer;

[0125] Step 3: Pour the epoxy resin prepolymer obtained in Step 2 into molds preheated to 60°C, degas in a vacuum drying oven for 30 minutes to remove residual air bubbles, and finally place in an oven for pre-curing at 95°C for 2 hours, curing at 135°C for 2 hours, and curing at 155°C for 2 hours to obtain low dielectric epoxy resin.

[0126] Figure 5 and Figure 6 These indicate that the co-curing agent, when integrated into the epoxy curing network, can improve or maintain tensile strength and reduce dielectric constant.

[0127] Comparative Example 1

[0128] A method for preparing an epoxy resin cured product includes the following steps:

[0129] Step 1: Mix 100 parts of bisphenol A type epoxy resin E-51 and 84 parts of curing agent methylhexahydrophthalic anhydride at 70°C until homogeneous. Then add 1 part of accelerator (2,4,6-tris(dimethylaminomethyl)phenol) and mix until homogeneous at 70°C to obtain epoxy resin prepolymer.

[0130] Step 2: Pour the epoxy resin prepolymer obtained in Step 1 into molds preheated to 60°C, degas in a vacuum drying oven for 30 minutes to remove residual air bubbles, and finally place in an oven for pre-curing at 95°C for 2 hours, curing at 135°C for 2 hours, and curing at 155°C for 2 hours to obtain the control epoxy resin cured product.

[0131] The epoxy resins prepared in Application Examples 1-4 and Comparative Example 1 were subjected to performance tests:

[0132] The performance testing methods are as follows: For tensile properties, dumbbell-shaped specimens were prepared according to the general method for tensile testing of plastics. The specimens were tested at room temperature using a universal testing machine, and the tensile strength and elongation at break were recorded. For dielectric properties, impedance analyzers or dielectric spectrometers were used to test the cured material at 10... 3 -10 5 The dielectric constant and dielectric loss in the Hz frequency range were measured. The samples were dried before testing to reduce the influence of moisture.

[0133] Comparative Example 1 used the same amounts of bisphenol A type epoxy resin, anhydride curing agent, and accelerator as Application Examples 1-4, but without adding a telechelic polynorbornene reactive co-curing agent. This was used to evaluate the effect of the reactive co-curing agent on the properties of the cured epoxy resin. The telechelic polynorbornene reactive co-curing agent contains carboxyl end groups and can participate in the construction of the curing network. However, its main function is as a reactive low-dielectric modifier containing low-polarity alicyclic segments, and it is not used to completely replace the anhydride curing agent of methylhexahydrophthalic anhydride in an equivalent amount.

[0134] The performance test results are shown in the table below:

[0135] Table 1. Performance test results of epoxy resins prepared in Application Examples 1-4 and Comparative Example 1

[0136]

[0137] Table 1 shows that the tensile strength of Application Examples 1-4 is higher than that of Comparative Example 1, indicating that the co-curing agent, after participating in network construction through the terminal carboxyl groups, does not destroy the epoxy curing network. On the contrary, it can adjust stress transfer through alicyclic segments and moderately flexible segments, thereby improving the mechanical stability of the cured product. Application Examples 1-4 at 10 5 The dielectric constant at Hz is lower than that of Comparative Example 1, indicating that the introduction of low-polarity polynorbornene or poly(norbornene-co-cyclopentene) segments can reduce the polarization of the system; the dielectric constants of the hydrogenated products in Application Examples 2 and 4 are further reduced, which may be related to the reduction of unsaturated bonds in the main chain, the reduction of structural polarity and the improvement of segment stability.

[0138] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A telechelic type polynorbornene reactive co-curing agent, characterized in that... The telechelic type polynorbornene reactive co-curing agent is a double-ended carboxyl oligomer obtained by olefin metathesis degradation of polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer, or a hydrogenated product of the obtained double-ended carboxyl oligomer.

2. The telechelic type polynorbornene reactive co-curing agent according to claim 1, characterized in that... The average molecular weight of the double-terminated carboxyl oligomers is 500-5000 g / mol.

3. A method for preparing the telechelicer type polynorbornene reactive co-curing agent according to claim 1 or 2, characterized in that: Teleclaw-type polynorbornene reactive co-curing agent I was obtained by degrading norbornene homopolymer with maleic acid. Alternatively, a remote claw-type poly(norbornene-co-cyclopentene) reactive co-curing agent III obtained by degrading the copolymer of norbornene and cyclopentene with maleic acid; Alternatively, the co-curing agent I can be hydrogenated to saturate double bonds to obtain a telechelic polynorbornene reactive co-curing agent II; Alternatively, the co-curing agent III can be hydrogenated to saturate double bonds to obtain a telechelic polynorbornene reactive co-curing agent IV.

4. The method for preparing a telechelic type polynorbornene reactive co-curing agent according to claim 3, characterized in that, The preparation methods of the co-curing agent I and co-curing agent III are as follows: Under a nitrogen atmosphere, polynorbornene homopolymer, poly(norbornene-co-cyclopentene) copolymer, maleic acid, and Grubbs2 were respectively mixed. nd The catalyst was stirred and reacted at 20-30℃ for 4-8 hours, then vinyl ether was added, and the reaction was stirred and reacted at 20-30℃ for 0.5-1 hours. Then, the mixture was rotary evaporated, extracted, and dried to constant weight to obtain telechelic polynorbornene reactive co-curing agent I and telechelic poly(norbornene-co-cyclopentene) reactive co-curing agent III, respectively.

5. The method for preparing a telechelicer-type polynorbornene reactive co-curing agent according to claim 3, characterized in that, The preparation methods of the polynorbornene homopolymer and poly(norbornene-co-cyclopentene) copolymer are as follows: Norbornene, a mixture of norbornene and cyclopentene, and Grubbs2 were respectively added. nd The catalyst was stirred at 20-30℃ for 1-2 hours, vinyl ether was added, and the mixture was stirred at 20-30℃ for 0.5-1 hours. Then, the mixture was rotary evaporated, precipitated, and dried to constant weight to obtain polynorbornene homopolymer or poly(norbornene-co-cyclopentene) copolymer.

6. The method for preparing a telechelicer-type polynorbornene reactive co-curing agent according to claim 3, characterized in that, The preparation methods of the co-curing agent II and co-curing agent IV are as follows: Under a nitrogen atmosphere, p-toluenesulfonyl hydrazine and xylene solvent were added to co-curing agent I and co-curing agent III, respectively. After complete dissolution, tri-n-propylamine was added. The mixture was stirred, refluxed, and cooled at 130-140℃ for 4-8 hours. Then, the mixture was rotary evaporated, precipitated, and dried to constant weight to obtain co-curing agent II and co-curing agent IV, respectively.

7. A low-dielectric epoxy resin, characterized in that, The components include the following parts by weight: 100 parts of bisphenol A type epoxy resin; 64-69 parts of curing agent; 5-20 parts of the teleclaw-type polynorbornene reactive co-curing agent as described in claim 1 or 2; Accelerator 0.8-1 part.

8. The low-dielectric epoxy resin according to claim 7, characterized in that... The bisphenol A type epoxy resin is E-51, the curing agent is methylhexahydrophthalic anhydride, and the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

9. A method for preparing the low-dielectric epoxy resin according to claim 7, characterized in that, Includes the following steps: (1) Mix the remote claw type polynorbornene reactive co-curing agent with the solvent, then add bisphenol A type epoxy resin and curing agent, and mix evenly at 60-80℃; (2) The solution obtained in step (1) is rotary evaporated at 20-30℃ to remove the solvent, and then an accelerator is added and mixed evenly at 60-80℃ to obtain epoxy resin prepolymer; (3) Pour the epoxy resin prepolymer obtained in step (2) into a preheated mold, degas it in a vacuum drying oven for 0.5-1h to remove residual air bubbles, and finally put it in an oven for pre-curing at 90-100℃ for 1.5-2.5h, curing at 130-140℃ for 1.5-2.5h, and curing at 150-160℃ for 1.5-2.5h to obtain low dielectric epoxy resin.

10. The application of the telechelic type polynorbornene reactive co-curing agent according to claim 1 or 2 in reducing the dielectric constant of anhydride-cured bisphenol A type epoxy resin.

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