CN114149684B - A kind of low-temperature curing low-dielectric high-toughness cyanate ester resin and preparation method thereof - Google Patents

Abstract

The invention discloses a low-temperature curing low-dielectric high-toughness cyanate resin and a preparation method thereof, belonging to the field of organic polymer synthesis and thermosetting resin modification. The invention does not change the existing mature cyanate resin system , the introduction of maleimidophenol containing double bonds and phenolic hydroxyl groups, not only can be cured under medium and high temperature conditions, but also can be rapidly cured under low temperature conditions below 130 ° C, and then prepared with low dielectric constant and High-toughness cyanate resin can improve the mechanical properties and dielectric properties of cyanate resin.

Description

A low-temperature curing low-dielectric high-toughness cyanate ester resin and preparation method thereof

technical field

The invention relates to a preparation method of low-temperature curing low-dielectric high-toughness cyanate resin, in particular maleimidophenol-modified cyanate resin, which belongs to the fields of organic polymer synthesis and thermosetting resin modification.

Background technique

Cyanate resins have attracted extensive attention from material science researchers due to their excellent mechanical properties, high heat resistance, low water absorption, good weather resistance and unique dielectric properties. However, the high curing temperature of cyanate resin, the high crosslink density and strong molecular rigidity of the cured product lead to poor toughness of cyanate resin. In order to make up for these shortcomings of cyanate resin, people have tried many modification methods in order to obtain a high-performance resin matrix. Commonly used methods include rubber elastomer blending, allyl compound copolymerization, thermosetting resin copolymerization, inorganic nanoparticle reinforcement, thermoplastic resin blending, and design and synthesis of cyanate esters with different structures. The product obtained by copolymerization modification of cyanate resin and thermosetting resin has an interpenetrating cross-linked network structure, which can well maintain the excellent properties of cyanate resin itself, especially the use of bismaleimide which has many excellent properties Copolymerization modification of amine resin. For example, Chinese patent CN109810468A utilizes a resin-modified epoxy-cyanate resin containing both maleimide groups and vinyl groups to improve the heat resistance and peel strength of the combined resin. Chinese patent CN112080111A uses maleimide-based phenolic epoxy resin to prepare a high heat-resistant and low-dielectric epoxy resin composition, which improves the rigidity and crosslinking density of the cured epoxy resin, and gives the cured product good heat resistance and dielectric properties. This is because the maleimide ring in the bismaleimide resin is a rigid structure, which can not only undergo self-polymerization but also copolymerize with cyanate groups during the reaction. The interpenetrating cross-linked network structure formed by the two It can realize the advantages and disadvantages of the two resins. However, the toughening modification effect of this system on cyanate resin is not significant, and the curing temperature is relatively high.

In order to reduce the curing temperature of cyanate resin, people have studied the curing kinetics of cyanate ester, and found that the method to reduce the curing temperature of cyanate resin is mainly chemical modification, and the modifier mainly includes epoxy-containing compounds and imine compounds. , Active hydrogen compounds and transition metal catalysts. Epoxy groups can react with cyanate esters, thereby reducing the curing temperature of cyanate ester resins. Aiming at the problem of high crosslinking and curing temperature of cyanate resin, the team of Zhang Chunhua from Harbin Institute of Technology disclosed a coordination and anion synergistically catalyzed curing cyanate resin system and its preparation method (CN107556749A). The cyanate resin and tertiary amine The base epoxy curing agent (AG-80, AG-90) is mixed according to a certain proportion for co-curing, and a new type of high-efficiency composite catalyst is added to the mixed resin system to perform gradient curing, which effectively reduces the activation energy of cyanate ester crosslinking and curing reactions. The curing temperature of the cyanate resin is reduced from 280° C. to 155° C., and the preparation of medium-temperature curing and high heat-resistant cyanate resin is realized. Chinese invention patent CN107459819A discloses a medium-temperature curing cyanate resin and its preparation method and application by using a compound catalyst of an active hydrogen compound, a transition metal organic compound, and an ultraviolet light-activated catalyst. Chinese patent CN109943223A discloses a modified cyanate ester. The invention uses the epoxy functional group on the surface of graphene to react with the triazine ring of the cyanate ester intermediate product during the curing process of the cyanate resin, thereby accelerating its curing process. U.S. Patent US2012/0178853A1 discloses a one-component cyanate-epoxy composite resin. The system is composed of cyanate monomer, epoxy resin, and bisphenol curing agent. The system is stable in storage and has excellent mechanical properties after curing. . European patent EP0544741B1 discloses a cyanate ester material for electronic products. Bisphenol A epoxy resin and bisphenol S are used as curing agents during curing. The obtained product is suitable for semiconductor materials, circuit boards, and insulating films.

Similarly, imine groups can also react with cyanate resins, thereby lowering the curing temperature of cyanate resins. Chinese patent CN103173012A reduces the curing peak temperature of the composite material from 246°C to 170.4°C by adding 2,2-diallyl bisphenol A, which improves the curing performance of the system. Cyanate groups can react with nucleophiles such as phenols, amines and transition metal complexes, effectively reducing the curing reaction temperature and shortening the curing time. Studies have shown that nonylphenol, cobalt acetylacetonate, bisphenols, dibutyltin dilaurate, etc. can all reduce the curing temperature of cyanate to a certain extent. For example, Chinese patent 202010019940.0 uses hydroquinone, phloroglucinol, 1,3,5-benzenetrimethanol and organic metal catalysts to modify cyanate esters, which effectively reduces the curing temperature of cyanate ester adhesives. Chinese invention patent CN111718685A discloses a cyanate ester adhesive with low curing temperature and high storage stability and a preparation method thereof by using modifiers such as benzoic acid, naphthoic acid, and p-nitrobenzoic acid.

Although people have made great progress in the research on the curing process of cyanate resin and its application, the existing curing system still has high curing temperature (concentrated at 155-180°C), decreased dielectric properties, and the The toughness enhancement of the ester is not obvious, the mechanical properties are reduced, and the like, especially it cannot be cured at low temperature while having good dielectric properties and mechanical properties. Our team (Ou Qiuren's team of Aerospace Special Materials and Technology Research Institute) disclosed a low-temperature curing agent system, cyanate resin system and preparation method (CN109721731A) in 2019, using active hydrogen-containing amine compounds as curing agents. Urea compounds, imidazole compounds or tertiary amine compounds are used as accelerators, and the synergistic effect of the two compounds is used to realize the curing of cyanate resin at 130°C. However, the toughening effect of this system on cyanate resin is average, and the actual curing process takes a long time, so there is room for further improvement in production efficiency.

Contents of the invention

In order to solve technical problems such as high curing temperature of cyanate ester resin, large residual stress of product, poor dimensional stability, etc., develop cyanate ester resin that can be cured rapidly at low temperature and has low dielectric constant and excellent mechanical properties. On the basis of not changing the existing mature cyanate ester resin system, maleimide phenol containing double bonds and phenolic hydroxyl groups is introduced to develop a rapid Cured cyanate resin with low dielectric constant and high toughness and preparation method thereof. The purpose of the present invention is to use maleimide phenol with good mechanical properties, electrical properties and heat resistance to catalyze cyanate ester polymerization and form an interpenetrating network with it, and prepare a low-temperature curing low-temperature Dielectric high toughness cyanate resin, reduce the curing temperature of cyanate resin, improve the mechanical properties and dielectric properties of cyanate resin.

The technical scheme that the present invention adopts for realizing the above object is as follows:

A low-temperature curing low-dielectric high-toughness cyanate ester resin, comprising the following components in parts by mass:

Further, the curing agent is 1-15 parts, the accelerator is 1-5 parts, the auxiliary agent is 0.5-5 parts, and the initiator is not more than 5 parts.

A preparation method for low-temperature curing low-dielectric high-toughness cyanate ester resin, comprising the following steps:

1) Mix 5-40 parts of epoxy resin with 1-20 parts of maleimidophenol at one time, heat up and stir evenly; or, mix part of 5-40 parts of epoxy resin with 1- Mix 20 parts of maleimide phenol, heat up and stir evenly, then add 2-30 parts of curing agent, accelerator and auxiliary agent, and then add 5-40 parts of the rest of the epoxy resin and mix evenly;

2) Add 20-80 parts of cyanate resin and mix well to obtain an epoxy resin-cyanate resin containing maleimidophenol;

3) Pouring the epoxy resin-cyanate resin containing maleimide phenol into the mold, vacuuming and removing air bubbles, and then preparing a low-dielectric and high-toughness cyanate resin through a curing process.

Further, the temperature of heating and stirring is 110-160°C, preferably 120-140°C.

Further, the phenolic hydroxyl group and the maleimide group in the maleimidophenol structural formula can be meta-position (formula 1), para-position (formula 2), ortho-position (formula 3), or one of them. A mixture of maleimidophenols of one or more structures.

Further, the cyanate resin is bisphenol A type cyanate resin, bisphenol F type cyanate resin, bisphenol M type cyanate resin, bisphenol E type cyanate resin, novolak type cyanate resin any one or more of them.

Further, the epoxy resin is bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, novolac type epoxy resin, multifunctional epoxy resin, alicyclic ring Any one or more of oxygen resins.

Further, the curing agent is a medium-temperature curing agent or a high-temperature curing agent: any one or more of m-phenylenediamine, dicyandiamide, diaminodiphenylsulfone, and diaminodiphenylmethane, and the number of parts by mass is 1-15 share.

Further, the accelerator is any one or more of substituted urea, imidazole, copper octoate, manganese octoate, and copper acetylacetonate, and the number of parts by mass is 1-5 parts.

Further, the auxiliary agent is any one or more of 9920 defoamer and 530 defoamer, and the parts by mass are 0.5-5 parts.

Further, add curing agent, accelerator and auxiliary agent and also add initiator simultaneously, and this initiator is tert-butyl hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate , any one or more of azobisisoheptanonitrile, the number of parts by mass is not more than 5 parts.

Further, the curing process is any one of the following:

(1) Low temperature curing: curing at one or more temperature points of 80-100°C and 110-130°C for 2-6 hours respectively;

(2) Medium temperature curing: sequentially cure at 80-100°C and 110-120°C for 1-4h respectively, and then successively cure at one or more temperature points in 130-190°C for 2-4h respectively;

(3) High temperature curing: curing at 80-100°C and 110-120°C for 1-4 hours respectively, and then curing at 130-150°C, 170-190°C and 220-250°C for 2-4 hours respectively.

The beneficial effect of the present invention compared with prior art:

(1) The present invention utilizes maleimide phenol with active double bonds and phenolic hydroxyl groups. On the one hand, phenolic hydroxyl groups can catalyze cyanate ester polymerization, reduce resin curing temperature and curing time, and on the other hand, in maleimide The double bond can be self-polymerized or copolymerized with epoxy-cyanate resin to form an interpenetrating network, thereby toughening the cyanate resin and improving the mechanical properties of the cyanate resin; realizing rapid curing of the cyanate resin at low temperature At the same time, it has excellent mechanical properties.

(2) The maleimide-based phenol used in the present invention has good mechanical properties, electrical properties and heat resistance, can catalyze cyanate ester polymerization to improve the degree of reaction after adding, and also participate in the reaction to reduce residual phenol in the system. Small molecules, so as to further improve the dielectric properties of cyanate ester resin and reduce its dielectric constant.

(3) The present invention introduces maleimide phenol on the basis of not changing the existing mature epoxy-cyanate resin system, not only the process is easy to operate, but also the curing temperature of the cyanate resin can be changed from the traditional The temperature condition above 240°C is extended to below 130°C, so that the curing can be carried out not only at medium and high temperature, but also at low temperature, which solves the problems caused by the high curing temperature of cyanate ester resin and the foam material with low temperature resistance Co-curing process issues.

(4) The present invention introduces maleimide with catalytic function in the traditional low-temperature curing system (using amine compounds containing active hydrogen as curing agent, urea compounds, imidazole compounds or tertiary amine compounds as accelerators) Based on phenol, the curing rate of the resin at low temperature is faster, and the curing time is further shortened.

(5) The maleimide group in the maleimide-based phenol used in the present invention can form an interpenetrating network with cyanate resin, and unlike bismaleimide, maleimide There is only one maleimide group in the base phenol, which does not increase the crosslinking density and has the effect of toughening.

(6) The resin system disclosed in the present invention has a low curing temperature and a small temperature difference with the environment, so the internal residual stress of the product is small, and the dimensional accuracy of the product is high, and it can be co-cured with various materials; in addition, the resin has high toughness and low temperature. Dielectric and other properties have broadened its application in electronic packaging, high-frequency communications, aerospace, automotive transportation, weaponry and other fields.

Description of drawings

Fig. 1 is the preparation flowchart of a kind of low-temperature curing low-dielectric high-toughness cyanate ester resin of the present invention.

Detailed ways

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

Example 1

Take 20 parts of bisphenol A epoxy resin E51, add 5 parts of 4-maleimidophenol (structural formula 2), add 5 parts of dicyandiamide, 3 parts of substituted urea, 1 part of 9920 defoamer, and stir well Finally, add 16 parts of E20 epoxy resin, add 50 parts of bisphenol A type cyanate (CE01), stir and mix evenly at 90°C, then pour it into a mold at 100°C, vacuumize for 15 minutes, and then heat it at 90°C, 110°C ℃ for 2 hours each, and 130 ℃ for 4 hours to obtain low-dielectric and high-toughness cyanate ester resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 2

Take 20 parts of bisphenol A type epoxy resin E51, add 2 parts of 4-maleimide phenol (structural formula 2), add 2 parts of m-maleimido phenol (structural formula 1), add 1 part of ortho Position 4-maleimidophenol (structural formula 3), add 5 parts of dicyandiamide, 1 part of substituted urea, 0.5 part of 530 defoamer, add 1 part of free radical initiator tert-butyl peroxybenzoate, stir After uniformity, add 15 parts of E20 epoxy resin, add 50 parts of bisphenol A type cyanate (CE01), stir and mix evenly at 90°C, then pour into a mold at 100°C, vacuum for 15 minutes, and then at 90°C, Keep at 110°C for 2 hours each, and at 130°C and 180°C for 4 hours each to obtain a low-dielectric and high-toughness cyanate ester resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 3

Take 9 parts of bisphenol A epoxy resin E51, add 3 parts of 4-maleimide phenol (structural formula 2), add 4 parts of dicyandiamide, 3 parts of substituted urea, 1 part of 530 defoamer, and stir well Then add 80 parts of bisphenol A cyanate (CE01), stir and mix evenly at 90°C, then pour into a mold at 100°C, vacuumize for 15 minutes, then keep at 80°C, 115°C for 4 hours, and at 140°C 6h, you can get low dielectric high toughness cyanate ester resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 4

Take 9 parts of bisphenol A epoxy resin E51, add 3 parts of 4-maleimide phenol (structural formula 2), add 1 part of dicyandiamide, 3 parts of substituted urea, 1 part of 530 defoamer, add free Base initiator tert-butyl peroxybenzoate 0.5 parts, stir well, add 80 parts of bisphenol A type cyanate (CE01), stir and mix evenly at 90°C, then pour into a mold at 100°C, vacuumize for 15 minutes , and then kept at 100°C and 120°C for 1 hour, and at 150°C for 3 hours, to obtain a low-dielectric and high-toughness cyanate ester resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 5

Take 40 parts of bisphenol A epoxy resin E51, add 20 parts of 4-maleimidophenol (structural formula 2), add 15 parts of dicyandiamide, 4 parts of substituted urea, 5 parts of 9920 defoamer, add free Based initiator tert-butyl peroxybenzoate 5 parts, add 20 parts of bisphenol A type cyanate (CE01), stir and mix evenly at 90°C, then pour into a mold at 100°C, vacuum for 15 minutes, and then Keep at 80°C and 115°C for 4 hours each, and at 130°C for 3 hours to obtain low dielectric and high toughness cyanate ester resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 6

Take 5 parts of bisphenol A epoxy resin E51, add 1 part of 4-maleimide phenol (structural formula 2), add 8 parts of dicyandiamide, 5 parts of substituted urea, 2 parts of 530 defoamer, and stir well Then add 50 parts of bisphenol A cyanate (CE01) and 30 parts of phenolic cyanate (CE05), stir and mix evenly at 90°C, then pour into a mold at 100°C, vacuum for 15 minutes, and then Keep at 100°C and 120°C for 1 hour respectively, and hold at 150°C and 190°C for 2 hours to obtain low dielectric and high toughness cyanate ester resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 7

The preparation process and parameters are basically the same as in Example 6, except for the curing process: curing at 80°C and 110°C for 4 hours each, and curing at 150°C, 190°C and 250°C for 2 hours each. The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 8

The preparation process and parameters are basically the same as in Example 6, except for the curing process: curing at 90°C and 115°C for 3 hours each, and curing at 140°C, 180°C and 230°C for 3 hours each. The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Example 9

The preparation process and parameters are basically the same as in Example 6, except for the curing process: curing at 100°C and 120°C for 1 hour, and curing at 130°C, 170°C and 220°C for 2 hours. The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

comparative example

To prepare a cyanate ester resin without maleimidophenol, the steps in Example 3 were repeated, except that no maleimidophenol was added. Take 12 parts of bisphenol A type epoxy resin E51, add 4 parts of dicyandiamide, 3 parts of substituted urea, 1 part of 530 defoamer, stir evenly, add 80 parts of bisphenol A type cyanate (CE01), at 90 Stir and mix evenly at ℃, then pour into a mold at 100°C, vacuumize for 15 minutes, then keep at 90°C, 110°C for 2 hours, and 130°C for 4 hours to obtain cyanate resin.

The dielectric and mechanical properties of the prepared cyanate resin are listed in Table 1.

Table 1 Dielectric properties and mechanical properties of different resin systems

It can be seen from Table 1 that the cyanate ester resin added with maleimidophenol has lower dielectric constant and dielectric loss, showing better dielectric properties. In addition, the addition of maleimidophenol can effectively improve the toughness of the resin, significantly improve the flexural strength and modulus of cyanate ester, and exhibit excellent mechanical properties. In addition, compared with the comparative example, the curing time of the cyanate ester resin added with maleimidophenol at 100°C was greatly reduced, only one-third of the comparative example. It can be seen that the maleimidophenol can Further promote the curing of cyanate ester, reduce the curing temperature and increase the curing rate.

The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent replacements, modifications or improvements can be made to the technical solutions and implementations of the present invention, all of which fall within the scope of the present invention. The protection scope of the present invention shall be determined by the appended claims.

Claims (9)

1. a low-temperature curing low-dielectric high-toughness cyanate ester resin is characterized in that, comprising the following components in parts by mass: Epoxy resin 5-40 parts; Cyanate resin 20-80 parts; Maleimidophenol 1-20 parts; Curing agent, accelerator and auxiliary agent 2-30 parts; Wherein, the phenolic hydroxyl group and the maleimide group in the structural formula of maleimidophenol are meta-position, para-position or ortho-position, corresponding to the following formula 1, formula 2, formula 3: , Or it is a mixture of maleimide phenols of one or more structures above. 2. low-temperature curing low-dielectric high-toughness cyanate ester resin as claimed in claim 1, is characterized in that, curing agent is 1-15 part, accelerator is 1-5 part, and auxiliary agent is 0.5-5 part, also Include no more than 5 parts of initiator. 3. a preparation method of low-temperature curing low-dielectric high-toughness cyanate ester resin, is characterized in that, comprises the following steps: 1) Mix 5-40 parts of epoxy resin with 1-20 parts of maleimide phenol at one time, heat up and stir evenly; or, mix part of 5-40 parts of epoxy resin with 1- Mix 20 parts of maleimide phenol, heat up and stir evenly, then add 2-30 parts of curing agent, accelerator and auxiliary agent, and then add 5-40 parts of the rest of the epoxy resin and mix evenly; Wherein, the phenolic hydroxyl group and the maleimide group in the structural formula of maleimidophenol are meta-position, para-position or ortho-position, corresponding to the following formula 1, formula 2, formula 3: , Or a mixture of maleimidophenols of one or more of the above structures; 2) Add 20-80 parts of cyanate resin and mix well to obtain an epoxy resin-cyanate resin containing maleimidophenol; 3) The epoxy resin-cyanate resin containing maleimide phenol was poured into the mold, vacuumed to remove air bubbles, and then cured to prepare a low-dielectric and high-toughness cyanate resin. 4. The method according to claim 3, characterized in that, the temperature of heating and stirring is 110-160°C. 5. method as claimed in claim 3 is characterized in that, cyanate resin is bisphenol A type cyanate resin, bisphenol F type cyanate resin, bisphenol M type cyanate resin, bisphenol E Any one or more of type cyanate resin and phenolic type cyanate resin. 6. method as claimed in claim 3, is characterized in that, epoxy resin is bisphenol A type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol A type epoxy resin, novolak type epoxy resin , any one or more of polyfunctional epoxy resins, and cycloaliphatic epoxy resins. 7. The method according to claim 3, wherein the curing agent is a medium-temperature curing agent or a high-temperature curing agent: any one of m-phenylenediamine, dicyandiamide, diaminodiphenylsulfone, and diaminodiphenylmethane One or more, the number of parts by mass is 1-15 parts; the accelerator is any one or more of substituted urea, imidazole, copper octoate, manganese octoate, copper acetylacetonate, the number of parts by mass is 1-5 parts; The auxiliary agent is any one or more of 9920 defoamer and 530 defoamer, and the mass part is 0.5~5 parts. 8. The method according to claim 3, characterized in that, adding curing agent, promotor and auxiliary agent also adding initiator, the initiator is tert-butyl hydroperoxide, dicumyl peroxide, peroxide Any one or more of di-tert-butyl, tert-butyl peroxybenzoate, and azobisisoheptanonitrile, the number of parts by mass is not more than 5 parts. 9. The method according to claim 3, wherein the curing process is any one of the following: (1) Low temperature curing: curing at one or more temperature points of 80-100°C and 110-130°C for 2-6 hours respectively; (2) Medium-temperature curing: sequentially cure at 80-100°C and 110-120°C for 1-4 hours, and then successively cure at one or more temperature points in the range of 130-190°C for 2-4 hours; (3) Curing at high temperature: Curing at 80-100°C and 110-120°C for 1-4 hours respectively, and then curing at 130-150°C, 170-190°C and 220-250°C for 2-4 hours respectively.

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