CN114149684B - Low-temperature-cured low-dielectric high-toughness cyanate 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 fields of organic polymer synthesis and thermosetting resin modification.

Description

Low-temperature-cured low-dielectric high-toughness cyanate 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 to maleimide phenol modified cyanate resin, belonging to the fields of organic polymer synthesis and thermosetting resin modification.

Background

Cyanate ester resins have gained extensive attention from materials researchers with excellent mechanical properties, high heat resistance, low water absorption, good weatherability, etc. properties and specific dielectric properties. However, the cyanate resin has the characteristics of high curing temperature, high crosslinking density of the cured product, high molecular rigidity and the like, so that the cyanate resin has poor toughness. In order to compensate for these disadvantages of the cyanate ester resins, many modification methods have been attempted in order to obtain a high-performance resin matrix. Common methods include rubber elastomer blending, allyl compound copolymerization, thermosetting resin copolymerization, inorganic nanoparticle reinforcement, thermoplastic resin blending, and modification methods for designing and synthesizing cyanate esters with different structures. The product obtained by copolymerization modification of the cyanate resin and the thermosetting resin has an interpenetrating crosslinked network structure, and the structure can well maintain the excellent performance of the cyanate resin, in particular to copolymerization modification by using bismaleimide resin with a plurality of excellent performances. For example, chinese patent CN109810468A uses 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 utilizes maleimide phenolic epoxy resin to prepare a high heat-resistant low-dielectric epoxy resin composition, so that the rigidity and the crosslinking density of an epoxy resin cured product are improved, and the cured product is endowed with good heat resistance and dielectric property. The maleimide ring in the bismaleimide resin is of a rigid structure, so that self-polymerization and copolymerization with cyanate groups can be realized in the reaction, and the interpenetrating crosslinked network structure formed by the maleimide ring and the cyanate groups can realize the complementary and short-term performances of the two resins. However, the system has no obvious toughening modification effect on the cyanate resin and has higher curing temperature.

In order to reduce the curing temperature of the cyanate ester resin, cyanate ester curing kinetics have been studied, and it has been found that the method of reducing the curing temperature of the cyanate ester resin is mainly chemical modification, and the modifier mainly includes an epoxy group-containing compound, an imine compound, an active hydrogen-containing compound, and a transition metal catalyst. The epoxy groups may react with the cyanate ester, thereby lowering the curing temperature of the cyanate ester resin. Aiming at the problem of high curing temperature of cyanate resin in cross-linking, the Harbin university of Industrial Zhang Chun wagons discloses a cyanate resin system for coordination and anion synergistic catalysis curing and a preparation method thereof (CN 107556749A), wherein cyanate resin and tertiary amine epoxy curing agent (AG-80, AG-90) are mixed according to a certain proportion to perform co-curing, a novel efficient compound catalyst is added into the mixed resin system to perform gradient curing, so that the activation energy of the cyanate resin cross-linking curing reaction is effectively reduced, the curing temperature of the cyanate resin is reduced from 280 ℃ to 155 ℃, and the preparation of medium-temperature curing and high-heat-resistance cyanate resin is realized. Chinese patent No. CN107459819A discloses a medium temperature curing cyanate resin, a preparation method and application thereof by utilizing a compound of active hydrogen, a transition metal organic compound and a compound catalyst of an ultraviolet light activated catalyst. Chinese patent CN109943223a discloses a modified cyanate, and the invention uses the epoxy functional group on the surface of graphene to react with the triazine ring of cyanate intermediate product in the curing process of cyanate resin, so as to accelerate the curing process. U.S. patent 2012/0178853A1 discloses a one-pack type cyanate-epoxy composite resin, wherein the system is composed of cyanate monomer, epoxy resin and bisphenol curing agent, and the system is stable in storage and has excellent mechanical properties after curing. European patent EP0544741B1 discloses a cyanate ester material for electronic products, which uses bisphenol a type epoxy resin and bisphenol S as curing agents during curing, and the obtained product is suitable for semiconductor materials, circuit boards and insulating films.

Similarly, imine groups may also react with the cyanate resin, thereby lowering the cyanate resin curing temperature. Chinese patent CN103173012A reduces the curing peak top temperature of the composite material from 246 ℃ to 170.4 ℃ by adding 2, 2-diallyl bisphenol A, and improves the curing performance of the system. The cyanate group can react with nucleophiles such as phenols, amines and transition metal complexes, thereby effectively reducing the curing reaction temperature and shortening the curing time. Studies show that nonylphenol, cobalt acetylacetonate, bisphenol compounds, dibutyltin dilaurate and the like can reduce the curing temperature of cyanate ester to a certain extent. For example, chinese patent 202010019940.0 utilizes hydroquinone, phloroglucinol, 1,3, 5-trimellitic alcohol and an organic metal catalyst to jointly modify cyanate ester, so that the curing temperature of the cyanate ester adhesive is effectively reduced. Chinese patent No. CN111718685A discloses a cyanate adhesive with low curing temperature and high storage stability by using modifiers such as benzoic acid, naphthoic acid, p-nitrobenzoic acid and the like, and a preparation method thereof.

Although research on the curing process of cyanate resin and application thereof have been greatly advanced, the existing curing system has the defects of higher curing temperature (concentrated at 155-180 ℃), reduced dielectric property, insignificant toughness enhancement of cyanate, reduced mechanical property and the like, and particularly has good dielectric property and mechanical property when curing at low temperature can not be realized. The team (European Qiu Ren team of the institute of special materials and process technology) discloses a low-temperature curing agent system, a cyanate resin system and a preparation method (CN 109721731A) in 2019, adopts an amine compound containing active hydrogen as a curing agent, adopts a urea compound, an imidazole compound or a tertiary amine compound as an accelerator, and realizes the curing of the cyanate resin at 130 ℃ by utilizing the synergistic effect of the two. However, the system has a general toughening effect on the cyanate resin, the actual curing process time is longer, and the production efficiency is further improved.

Disclosure of Invention

In order to solve the technical problems of high curing temperature, large residual stress of products, poor dimensional stability and the like of cyanate ester resin, the cyanate ester resin which can be cured rapidly at low temperature and has low dielectric constant and excellent mechanical property is developed. The invention aims to prepare low-temperature-cured low-dielectric high-toughness cyanate resin by using a simple preparation method, reduce the curing temperature of the cyanate resin and improve the mechanical property and dielectric property of the cyanate resin by catalyzing the cyanate polymerization with maleimido phenol with good mechanical property, electrical property and heat resistance to form an interpenetrating network with the cyanate.

The technical scheme adopted by the invention for achieving the purpose is as follows:

the low-temperature cured low-dielectric high-toughness cyanate resin comprises 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 curing agent further comprises not more than 5 parts of initiator.

A preparation method of low-temperature cured low-dielectric high-toughness cyanate resin comprises the following steps:

1) Mixing 5-40 parts of epoxy resin with 1-20 parts of maleimide phenol at one time, and heating and stirring uniformly; or mixing part of 5-40 parts of epoxy resin with 1-20 parts of maleimide phenol, heating and stirring uniformly, then adding 2-30 parts of curing agent, accelerator and auxiliary agent, and then adding the rest part of 5-40 parts of epoxy resin and mixing uniformly;

2) Adding 20-80 parts of cyanate resin and uniformly mixing to obtain epoxy resin-cyanate resin containing maleimido phenol;

3) And (3) pouring the epoxy resin-cyanate resin containing the maleimido phenol into a mould, vacuumizing to remove bubbles, and then preparing the low-dielectric high-toughness cyanate resin through a curing process.

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

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

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

Further, the epoxy resin is any one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, brominated bisphenol A epoxy resin, phenolic epoxy resin, polyfunctional epoxy resin and alicyclic epoxy resin.

Further, the curing agent is a medium temperature curing agent or a high temperature curing agent: is one or more of m-phenylenediamine, dicyandiamide, diaminodiphenyl sulfone and diaminodiphenyl methane, and the mass portion is 1-15.

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

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

Further, a curing agent, an accelerator and an auxiliary agent are added, and an initiator is added at the same time, wherein the initiator is any one or more of tert-butyl hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate and azodiisoheptonitrile, and the mass portion of the initiator is not more than 5 portions.

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

(1) Curing at low temperature: sequentially curing at one or more temperature points of 80-100deg.C and 110-130deg.C for 2-6 hr;

(2) Medium temperature curing: sequentially curing at 80-100deg.C and 110-120deg.C for 1-4 hr, and sequentially curing at 130-190 deg.C at one or more temperature points for 2-4 hr;

(3) High temperature curing: sequentially curing at 80-100deg.C and 110-120deg.C for 1-4 hr, and sequentially curing at 130-150deg.C, 170-190 deg.C and 220-250deg.C for 2-4 hr.

Compared with the prior art, the invention has the beneficial effects that:

(1) The invention utilizes the maleimido phenol with active double bond and phenolic hydroxyl, on one hand, the phenolic hydroxyl can catalyze the cyanate to polymerize, reduce the curing temperature and curing time of the resin, and on the other hand, the double bond in the maleimide can self-polymerize or copolymerize with the epoxy-cyanate resin to form an interpenetrating network, thereby toughening the cyanate resin and improving the mechanical property of the cyanate resin; realizes the low-temperature rapid solidification of the cyanate resin and simultaneously has excellent mechanical properties.

(2) The maleimido phenol used in the invention has good mechanical property, electrical property and heat resistance, can catalyze the cyanate polymerization to improve the reaction degree after being added, and can participate in the reaction to reduce residual micromolecules in the system, thereby further improving the dielectric property of the cyanate resin and reducing the dielectric constant of the cyanate resin.

(3) The invention introduces maleimide phenol on the basis of not changing the existing mature epoxy-cyanate ester resin system, has simple and convenient process operation, and can expand the curing temperature of cyanate ester resin from the traditional temperature condition of more than 240 ℃ to below 130 ℃, so that the curing can be carried out at medium and high temperatures and also can be carried out at low temperature, and solves the technical problem that the curing temperature of the cyanate ester resin is high and the curing temperature cannot be carried out together with a foam material with low temperature resistance.

(4) In the invention, the maleimido phenol with a catalytic function is introduced into a traditional low-temperature curing system (taking an amine compound containing active hydrogen as a curing agent and a urea compound, an imidazole compound or a tertiary amine compound as an accelerator), so that the curing rate of the resin at low temperature is faster, and the curing time is further shortened.

(5) The maleimide groups in the maleimide-based phenol adopted in the invention can form an interpenetrating network with cyanate resin, and unlike bismaleimides, only one maleimide group in the maleimide-based phenol has the toughening effect without increasing the crosslinking density.

(6) The resin system disclosed by the invention has low curing temperature and small temperature difference from the environment, so that the residual stress in the product is small, the dimensional accuracy of the obtained product is high, and the product can be co-cured with various materials; in addition, the resin has the properties of high toughness, low dielectric property and the like, and widens the application of the resin in the fields of electronic packaging, high-frequency communication, aerospace, automobile traffic, weaponry and the like.

Drawings

FIG. 1 is a flow chart of the preparation of a low temperature cured low dielectric high toughness cyanate ester resin of the present invention.

Detailed Description

In order to make the above features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.

Example 1

Taking 20 parts of bisphenol A epoxy resin E51, adding 5 parts of 4-maleimidophenol (structural formula 2), adding 5 parts of dicyandiamide, 3 parts of substituted urea, 1 part of 9920 defoamer, uniformly stirring, adding 16 parts of E20 epoxy resin, adding 50 parts of bisphenol A cyanate (CE 01), uniformly stirring and mixing at 90 ℃, pouring into a mould at 100 ℃, vacuumizing for 15 minutes, and then keeping at 90 ℃ and 110 ℃ for 2h and 130 ℃ for 4h respectively, thus obtaining the low-dielectric high-toughness cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 2

20 parts of bisphenol A epoxy resin E51 is taken, 2 parts of 4-maleimidophenol (structural formula 2) is added, 2 parts of meta-maleimidophenol (structural formula 1) is added, 1 part of ortho-4-maleimidophenol (structural formula 3) is added, 5 parts of dicyandiamide is added, 1 part of substituted urea, 0.5 part of 530 defoamer is added, 1 part of radical initiator tert-butyl peroxybenzoate is added, 15 parts of E20 epoxy resin is added after stirring uniformly, 50 parts of bisphenol A cyanate (CE 01) is added, stirring uniformly at 90 ℃, then the mixture is poured into a mold at 100 ℃, vacuumizing is carried out for 15 minutes, and then each of the materials is kept at 90 ℃ for 2 hours, 130 ℃ and 180 ℃ for 4 hours, thus obtaining the low-dielectric high-toughness cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 3

9 parts of bisphenol A epoxy resin E51 is taken, 3 parts of 4-maleimide phenol (structural formula 2) is added, 4 parts of dicyandiamide is added, 3 parts of urea is substituted, 1 part of 530 defoamer is added, 80 parts of bisphenol A cyanate (CE 01) is added after uniform stirring, the mixture is stirred and mixed uniformly at 90 ℃, then the mixture is poured into a mould at 100 ℃, vacuumized for 15 minutes, and then kept at 80 ℃ and 115 ℃ for 4 hours and 140 ℃ for 6 hours respectively, thus obtaining the low-dielectric high-toughness cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 4

9 parts of bisphenol A epoxy resin E51 is taken, 3 parts of 4-maleimide phenol (structural formula 2) is added, 1 part of dicyandiamide is added, 3 parts of urea is substituted, 1 part of a 530 defoamer is added, 0.5 part of radical initiator tert-butyl peroxybenzoate is added, 80 parts of bisphenol A cyanate (CE 01) is added after uniform stirring, stirring and mixing are carried out at 90 ℃, then the mixture is poured into a mould at 100 ℃, vacuumizing is carried out for 15 minutes, and then the mixture is kept at 100 ℃ and 120 ℃ for 1h and 150 ℃ for 3h respectively, thus obtaining the low-dielectric high-toughness cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 5

40 parts of bisphenol A epoxy resin E51 is taken, 20 parts of 4-maleimidophenol (structural formula 2) is added, 15 parts of dicyandiamide is added, 4 parts of substituted urea, 5 parts of free radical initiator tert-butyl peroxybenzoate is added, 20 parts of bisphenol A cyanate (CE 01) is added, the mixture is stirred and mixed uniformly at 90 ℃, then the mixture is poured into a mould at 100 ℃, vacuumized for 15 minutes, and then the mixture is kept at 80 ℃ and 115 ℃ for 4 hours and at 130 ℃ for 3 hours respectively, thus obtaining the low-dielectric high-toughness cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 6

Taking 5 parts of bisphenol A epoxy resin E51, adding 1 part of 4-maleimide phenol (structural formula 2), adding 8 parts of dicyandiamide, 5 parts of substituted urea, 2 parts of 530 defoamer, uniformly stirring, adding 50 parts of bisphenol A cyanate (CE 01), 30 parts of phenolic cyanate (CE 05), uniformly stirring and mixing at 90 ℃, pouring into a mould at 100 ℃, vacuumizing for 15 minutes, and then keeping at 100 ℃ and 120 ℃ for 1h and at 150 ℃ and 190 ℃ for 2h respectively to obtain the low-dielectric high-toughness cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 7

The preparation process and parameters were essentially the same as in example 6, except for the curing process: curing at 80deg.C and 110deg.C for 4 hr, and at 150deg.C and 190deg.C and 250deg.C for 2 hr. The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 8

The preparation process and parameters were essentially the same as in example 6, except for the curing process: curing at 90deg.C and 115deg.C for 3 hr, and at 140deg.C and 180deg.C and 230deg.C for 3 hr. The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Example 9

The preparation process and parameters were essentially the same as in example 6, except for the curing process: curing at 100deg.C and 120deg.C for 1 hr, and at 130deg.C and 170deg.C and 220deg.C for 2 hr. The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

Comparative example

The procedure of example 3 was repeated except that maleimide-based phenol was not added. Taking 12 parts of bisphenol A epoxy resin E51, adding 4 parts of dicyandiamide, 3 parts of substituted urea and 1 part of 530 defoamer, stirring uniformly, adding 80 parts of bisphenol A cyanate (CE 01), stirring uniformly at 90 ℃, pouring into a mold at 100 ℃, vacuumizing for 15 minutes, and then keeping at 90 ℃ and 110 ℃ for 2h and 130 ℃ for 4h respectively to obtain the cyanate resin.

The dielectric and mechanical properties of the cyanate ester resins prepared are shown in table 1.

TABLE 1 dielectric Properties and mechanical Properties of different resin systems

As can be seen from table 1, the cyanate ester resin added with maleimidophenol has lower dielectric constant and dielectric loss, exhibiting better dielectric properties. In addition, the addition of the maleimido phenol can effectively improve the toughness of the resin, obviously improve the bending strength and modulus of the cyanate ester and show excellent mechanical properties. In addition, compared with the comparative example, the curing time of the cyanate ester resin added with the maleimido phenol at 100 ℃ is greatly shortened, which is only one third of that of the comparative example, and the maleimido phenol can further promote the curing of the cyanate ester, reduce the curing temperature and improve the curing rate.

The invention has been described in detail in connection with the specific embodiments and exemplary examples thereof, but such description is not to be construed as limiting the invention. It will be understood by those skilled in the art that various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its embodiments without departing from the spirit and scope of the present invention, and these fall within the scope of the present invention. The scope of the invention is defined by the appended claims.

Claims (9)

1. The low-temperature curing low-dielectric high-toughness cyanate resin is characterized by comprising the following components in parts by weight:

5-40 parts of epoxy resin;

20-80 parts of cyanate resin;

1-20 parts of maleimide phenol;

2-30 parts of curing agent, accelerator and auxiliary agent;

wherein, phenolic hydroxyl and maleimide groups in the structural formula of the maleimide phenol are meta, para or ortho, and correspond to the following formulas 1, 2 and 3:

，

or a mixture of maleimide-based phenols of one or more of the structures described above.

2. The low temperature cure low dielectric high toughness cyanate ester resin according to claim 1, wherein the curing agent is 1-15 parts, the promoter is 1-5 parts, the auxiliary agent is 0.5-5 parts, and the initiator is not more than 5 parts.

3. The preparation method of the low-temperature cured low-dielectric high-toughness cyanate resin is characterized by comprising the following steps of:

1) Mixing 5-40 parts of epoxy resin with 1-20 parts of maleimide phenol at one time, and heating and stirring uniformly; or mixing part of 5-40 parts of epoxy resin with 1-20 parts of maleimide phenol, heating and stirring uniformly, then adding 2-30 parts of curing agent, accelerator and auxiliary agent, and then adding the rest part of 5-40 parts of epoxy resin and mixing uniformly; wherein, phenolic hydroxyl and maleimide groups in the structural formula of the maleimide phenol are meta, para or ortho, and correspond to the following formulas 1, 2 and 3:

，

or a mixture of one or more of the above structures of maleimidophenols;

2) Adding 20-80 parts of cyanate resin and uniformly mixing to obtain epoxy resin-cyanate resin containing maleimido phenol;

3) And (3) pouring the epoxy resin-cyanate resin containing the maleimido phenol into a mould, vacuumizing to remove bubbles, and then preparing the low-dielectric high-toughness cyanate resin through a curing process.

4. A method according to claim 3, wherein the temperature of the elevated temperature agitation is 110-160 ℃.

5. The method of claim 3, wherein the cyanate resin is any one or more of bisphenol a type cyanate resin, bisphenol F type cyanate resin, bisphenol M type cyanate resin, bisphenol E type cyanate resin, phenolic type cyanate resin.

6. The method of claim 3, wherein the epoxy resin is any one or more of bisphenol a type epoxy resin, bisphenol F type epoxy resin, brominated bisphenol a type epoxy resin, phenolic type epoxy resin, polyfunctional epoxy resin, and cycloaliphatic epoxy resin.

7. A method according to claim 3, wherein the curing agent is a medium temperature curing agent or a high temperature curing agent: is one or more of m-phenylenediamine, dicyandiamide, diaminodiphenyl sulfone and diaminodiphenyl methane, and the mass part is 1-15; the accelerator is any one or more of substituted urea, imidazole, copper octoate, manganese octoate and copper acetylacetonate, and the weight part is 1-5; the auxiliary agent is any one or more of 9920 defoamer and 530 defoamer, and the mass portion is 0.5-5.

8. The method according to claim 3, wherein the curing agent, the accelerator and the auxiliary agent are added together with an initiator, and the initiator is any one or more of tert-butyl hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate and azodiisoheptonitrile, and the mass fraction of the initiator is not more than 5 parts.

9. A method according to claim 3, wherein the curing process is any one of the following:

(1) Curing at low temperature: sequentially curing at one or more temperature points of 80-100deg.C and 110-130deg.C for 2-6 hr;

(2) Medium temperature curing: sequentially curing at 80-100deg.C and 110-120deg.C for 1-4 hr, and sequentially curing at 130-190 deg.C at one or more temperature points for 2-4 hr;

(3) High temperature curing: sequentially curing at 80-100deg.C and 110-120deg.C for 1-4 hr, and sequentially curing at 130-150deg.C, 170-190 deg.C and 220-250deg.C for 2-4 hr.

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