CN111718685A

CN111718685A - Cyanate ester adhesive with low curing temperature and high storage stability and preparation method thereof

Info

Publication number: CN111718685A
Application number: CN202010646806.3A
Authority: CN
Inventors: 马寒冰; 卿锐
Original assignee: Suining Luxshare Precision Industry Co Ltd
Current assignee: Suining Luxshare Precision Industry Co Ltd
Priority date: 2020-07-07
Filing date: 2020-07-07
Publication date: 2020-09-29
Anticipated expiration: 2040-07-07
Also published as: CN111718685B

Abstract

The invention discloses a cyanate ester adhesive with low curing temperature and high storage stability and a preparation method thereof, wherein the cyanate ester adhesive comprises cyanate ester resin, a modifier and a transition metal catalyst; the modifier is selected from one or more of benzoic acid, naphthoic acid and p-nitrobenzoic acid; the dosage of the modifier and the transition metal catalyst is as follows: 1-7 g of modifier and 0.02-0.5 g of transition metal catalyst are added into 100g of cyanate ester resin. The cyanate adhesive can be completely cured at a relatively low temperature, and a cured product has low dielectric constant and dielectric loss, excellent storage stability, can be stored for a long time without deterioration, and is convenient for storage, transportation and use of cyanate. The cyanate adhesive disclosed by the invention is simple in preparation process, does not use toxic and harmful raw materials or solvents, is environment-friendly and pollution-free in process, low in production cost and simple in equipment requirement, can realize large-scale industrial production, and is worthy of popularization and application.

Description

Cyanate ester adhesive with low curing temperature and high storage stability and preparation method thereof

Technical Field

The invention belongs to the technical field of high molecular compound materials, and particularly relates to a cyanate ester adhesive with low curing temperature and high storage stability and a preparation method thereof.

Background

Cyanate Ester Resin (Cyanate Ester Resin) is a kind of Resin with a terminal group having-OCN chemical group, and can form triazine ring after curing, so that the Cyanate Ester Resin has excellent characteristics of low dielectric constant, low dielectric loss, low moisture absorption rate, low volume shrinkage, high heat resistance and the like, and is an ideal adhesive for electronic products. However, because the triazine ring formed after the cyanate ester resin is cured has highly symmetrical structure, high crystallinity and high crosslinking density, the common cyanate ester can be completely cured at a higher temperature (generally equal to or higher than 220 ℃).

However, when the adhesive is used for bonding electronic products, the curing temperature is required to be not too high (generally required to be less than or equal to 200 ℃), otherwise, the bonded electronic components are easy to crack due to larger thermal stress. Ordinary cyanate can not be completely cured at a relatively low temperature, and the residual strong polar-OCN chemical group can reduce the heat resistance of the cyanate, so that the application of the cyanate in electronic products is limited. In addition, in a relatively closed space, residual impurities such as bisphenol A, cyanogen bromide and the like in the common cyanate resin are easy to volatilize at high temperature to generate bubbles, so that the electrical property and the thermal property of the whole electronic device are influenced.

At present, the method for reducing the curing temperature of the cyanate ester resin is mainly chemical modification, and the modifier mainly comprises an epoxy group-containing compound, an imine compound, an active hydrogen-containing compound and a transition metal catalyst.

The epoxy group can react with the-OCN, thereby reducing the curing temperature of the cyanate ester resin. Such as: chinese patent CN109943223A discloses a modified cyanate ester, the invention utilizes graphene modified cyanate ester resin modified by epoxy group, researches show that the epoxy functional group on the surface of graphene can react with triazine ring of cyanate ester intermediate product in the curing process of cyanate ester resin, thus accelerating the curing process; U.S. Pat. No. 2012/0178853A1 discloses one-liquid type cyanate-epoxy composite resin, wherein a system consists of a cyanate monomer, epoxy resin and a bisphenol curing agent, the system is stable in storage, and has excellent mechanical properties and flame retardant properties after being cured; european patent EP 0544741B1 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.

The imine group may also react with-OCN, thereby lowering the cyanate ester resin cure temperature. Such as: chinese patent CN103173012A discloses a 2, 2-diallyl bisphenol A modified bismaleimide-cyanate ester resin composite material, by adding 20% of 2, 2-diallyl bisphenol A, the curing peak top temperature of the composite material can reach 170.4 ℃, while the curing peak top temperature of the traditional bismaleimide-triazine resin is 246.2 ℃, so that the curing performance of the system is greatly improved; chinese patent CN 109943071A discloses a modified cyanate ester resin with high glass transition temperature, polysiloxane is modified as a modifier, and the prepared composite material has high strength, high modulus, excellent shape memory performance and higher glass transition temperature.

The active hydrogen-containing compound and the transition metal catalyst have different effects on the curing temperature of the cyanate ester resin and the properties of the cured product. The cyanate group can react with nucleophiles such as phenols, amines and transition metal complexes, mainly because of the highly electrophilic carbon atom in the-OCN group. The intermediate product (such as carbamate) obtained in the reaction can further catalyze the cyclotrimerization reaction of cyanate, effectively reduce the curing reaction temperature and shorten the curing time, thereby improving the process performance. For example, Lin utilizes 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to modify cyanate ester, and research shows that the whole curing peak of a modification system is reduced by about 21-76 ℃, and the flame retardance of a modified cured product can reach V-0 level and the thermal stability is obviously reduced along with the increase of phosphorus content; chen Xi, etc. combines triglycidyl isocyanate (TGIC) or triallyl isocyanate (TAIC) with DOPO and cyanate to prepare a modified cyanate resin, and the result shows that the curing temperature and the glass transition temperature of the modified blend are lower than those of pure cyanate, and the modified blend has good flame retardant property and dielectric property; clara M.Go' mez et al modified bisphenol A cyanate with nonylphenol, cobalt acetylacetonate, and the addition of modifier provided cyanate with better curing properties, when 2 wt% Nonylphenol (NP) was used, the concentration of cobalt (II) acetate increased from 0 to 1000ppm, and the maximum peak temperature (T) of bisphenol A cyanate_P) From 314 ℃ down to 163 ℃; for bells, etc. of high tanglingDiallyl bisphenol A (DAB) and bisphenol A respectively modify bisphenol E type cyanate, and the influence of bisphenol compounds on the curing property of the cyanate is studied; in addition, diallyl bisphenol A catalytic modified phenolic cyanate resin is also researched by Maristian and the like, and the result shows that the catalytic curing effect of the 10% diallyl bisphenol A doped modified phenolic cyanate resin is most obvious, and the curing peak temperature is reduced by about 100 ℃ compared with that of pure resin; guo et al prepared diallyl bisphenol A and diphenylmethane bismaleimide modified cyanate ester resins, and the modified cyanate ester resins had a reduced cure initiation temperature of about 60 ℃ and a Tg of about 270 ℃. The dielectric loss is 0.008-0.01 at 7-15 GHz; wangli et al prepared an asymmetric bisphenol B cyanate by using 2, 2-bis (4-hydroxyphenyl) butane (bisphenol B) and hydrogen bromide, and studied the curing reaction process of bisphenol B cyanate and bisphenol A cyanate, the results showed that the catalyst dibutyltin dilaurate had the best catalytic effect on bisphenol B cyanate, the thermal properties of bisphenol B cyanate were superior to those of bisphenol A cyanate, and both had similar mechanical properties and good dielectric properties. According to the Chinese patent 202010019940.0, hydroquinone, phloroglucinol, 1,3, 5-benzenetriol and an organic metal catalyst are jointly used for modifying the cyanate ester, so that the curing temperature of the cyanate ester adhesive is effectively reduced, the bonding property of the cyanate ester is improved, and the cyanate ester adhesive is high in heat resistance and good in dielectric property.

Although the above strategies can reduce the curing temperature of cyanate ester, almost all of them have the problem of reducing the storage stability of cyanate ester. For example, the influence of several metal ions on the curing activity of the cyanate is tested in the blue and text, and the result shows that different metal ions have great influence on the gel time of the cyanate and the storage period is shortened; cinnabar and the like compound phenol with transition metal ions, when the addition amount of phenol is 20phr, the curing initial temperature of the cyanate ester resin is reduced from 202.8 ℃ to 113.4 ℃, but the modified cyanate ester normal-temperature storage region is found to be shortened, the viscosity is increased by 64 times after being placed at room temperature for 31 days, and the viscosity is increased by only 2 times after being placed at room temperature for 31 days after 0.05 parts of stabilizer is used.

It can be seen that, although the curing temperature of cyanate can be lowered by modification, the storage property of cyanate is poor, and cyanate is easy to deteriorate, which is very unfavorable for storage, transportation and use of cyanate.

Therefore, how to reduce the curing temperature of the cyanate ester and ensure that the storage stability of the modified cyanate ester is not affected is a technical problem to be solved urgently in the field, and the development of a cyanate ester adhesive which has good adhesion, can be cured at a lower temperature and has good storage stability is urgent.

Disclosure of Invention

The invention mainly solves the technical problem of providing a modified cyanate adhesive which is low in curing temperature.

In order to solve the above problems, the present invention provides a cyanate ester adhesive with low curing temperature and high storage stability, which comprises a cyanate ester resin, a modifier and a transition metal catalyst;

the modifier is selected from one or more of benzoic acid, naphthoic acid and p-nitrobenzoic acid;

the dosage of the modifier and the transition metal catalyst is as follows: 1-7 g of modifier and 0.02-0.5 g of transition metal catalyst are added into 100g of cyanate ester resin.

According to the invention, researches show that when one or more of benzoic acid, naphthoic acid and p-nitrobenzoic acid is/are used as a modifier, the effect of reducing the curing temperature is superior to that of the currently used more bisphenols, nonylphenol and the like, and the three modifiers have stronger activity and stronger acceleration effect on cyanate curing.

In addition, tests show that when one or more of benzoic acid, naphthoic acid and paranitrobenzoic acid is/are used as the modifier (benzoic acid is not selected independently), cyanate curing can be promoted better, the influence on the heat resistance and dielectric property of cyanate is reduced, the dielectric property is improved compared with that before modification, the storage stability of cyanate can be guaranteed to be hardly influenced, and the problem that the storage stability of cyanate can be greatly reduced by the modifier in the prior art is solved.

The benzoic acid has a relatively low melting point (122 ℃), is easy to melt, is easy to be compatible with the molten bisphenol A cyanate (the melting point is about 80 ℃), and has a strong catalytic effect on the cyanate, but in the invention, only the benzoic acid and metal ions are used as modifiers, so that the influence on the storage period of the cyanate is large; although the structures of p-nitrobenzoic acid and naphthoic acid are similar to that of benzoic acid, the influence on the storage period is obviously different, and the inventor further analyzes the principle according to the test result:

on one hand, the nitro group in the p-nitrobenzoic acid is an electron-withdrawing group and has a promoting effect on the activity of H in carboxyl, so that the chemical reaction activity with cyanate is stronger; on the other hand, p-nitrobenzoic acid has a high melting point (about 240 ℃), is not easily melted, and exists mainly as a solid when blended with molten cyanate ester, so that the reaction speed is relatively slow when reacting with cyanate ester. Under the comprehensive effects of the two aspects, the paranitrobenzoic acid can play a chemical catalysis role in the thermocuring of the cyanate, but the catalytic reaction is slow, the paranitrobenzoic acid is used as a modifier, the reaction temperature is relatively high, the reaction time is relatively long, and the cyanate modified by the paranitrobenzoic acid is relatively stable to store at normal temperature.

Naphthoic acid has a higher melting point (about 185 ℃) than benzoic acid, is not easily melted, and exists mainly as a solid when blended with molten cyanate ester, so that the reaction speed is relatively slow when reacting with cyanate ester; from the chemical structure, one more conjugated benzene ring is added on the molecular structure, the reactivity of carboxyl is reduced, the reactivity with cyanate is lower than that of benzoic acid, and the reactivity is further reduced due to larger steric hindrance of the molecule, the reaction temperature of cyanate modified by the modified cyanate is relatively higher, and the reaction time is relatively longer.

The invention uses the three carboxylic acids with similar structures to jointly catalyze the cyanate, can effectively coordinate and control the curing reaction temperature and the reaction time of the cyanate resin, and realizes the reasonable matching of the curing temperature and the storage time.

In a specific embodiment of the present invention, the modifier and the transition metal catalyst are used in the following amounts: adding 1.5-5 g of modifier and 0.05-0.2 g of transition metal catalyst into every 100g of cyanate ester resin; preferably, 1.5-2.5 g of modifier and 0.05-0.1 g of transition metal catalyst are added to 100g of cyanate ester resin.

Further, the modifier is a mixture of benzoic acid, naphthoic acid and p-nitrobenzoic acid.

In a specific embodiment of the present invention, 0.5 to 2g of benzoic acid, 0.5 to 2g of naphthoic acid, and 0.5 to 2g of p-nitrobenzoic acid are added to 100g of cyanate ester resin.

Further, 0.5g of benzoic acid, 0.5-1 g of naphthoic acid and 0.5-1 g of p-nitrobenzoic acid are added to 100g of cyanate ester resin.

Further, the dosage of the benzoic acid, the naphthoic acid and the p-nitrobenzoic acid is selected from one of the following:

i. 0.5g of benzoic acid, 0.5g of naphthoic acid and 0.5g of p-nitrobenzoic acid are added into 100g of cyanate ester resin;

adding 0.5g of benzoic acid, 1g of naphthoic acid and 1g of p-nitrobenzoic acid into 100g of cyanate ester resin;

further, when the amount is i, the amount of the transition metal catalyst is 0.05g per 100g of the cyanate ester resin; in the case of the amount ii, the amount of the transition metal catalyst is 0.1g per 100g of the cyanate ester resin.

When the three modifiers are selected from the two mixture ratios, the reduction of the curing temperature and the guarantee of good storage stability can be simultaneously realized, and the modifier is obtained for the invention.

In a specific embodiment of the invention, the organometallic catalyst is cobalt acetylacetonate.

In a specific embodiment of the present invention, the cyanate ester resin is bisphenol a type cyanate ester.

The invention also provides a preparation method of the cyanate adhesive with low curing temperature and high thermal stability, which comprises the following steps:

(1) melting cyanate ester resin, cooling to 75-90 ℃, mixing with a modifier, and stirring until the mixture is transparent to obtain a premixed adhesive;

(2) and (2) mixing the premixed adhesive prepared in the step (1) with a transition metal catalyst at the temperature of 75-90 ℃.

Furthermore, the temperature for melting the cyanate ester resin is 100-120 ℃, preferably 110-115 ℃.

Further, the temperature of the mixture in the step (1) or the step (2) is 80-85 ℃. The invention has the beneficial effects that:

(1) the cyanate adhesive can be completely cured at a relatively low temperature, and a cured product has low dielectric constant and dielectric loss, excellent storage stability, can be stored for a long time without deterioration, and is convenient for storage, transportation and use of cyanate.

(2) The cyanate adhesive disclosed by the invention is simple in preparation process, does not use toxic and harmful raw materials or solvents, is environment-friendly and pollution-free in process, low in production cost and simple in equipment requirement, and can realize large-scale industrial production.

Detailed Description

The technical solutions of the present invention are described clearly and completely below, and it is obvious that the described embodiments are some, not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the embodiment of the invention, the usage amount of the matrix cyanate ester resin is 100g, after the adhesives prepared in the embodiment are vacuumized for 30min (with the pressure of 0.01MPa) until no air bubbles exist, the corresponding performance is tested after the adhesives are cured by a curing process of 140 ℃ multiplied by 1h +160 ℃ multiplied by 2h +180 ℃ multiplied by 2h +200 ℃ multiplied by 3h, and the adhesives are used for comparing the effects of the embodiment.

Wherein the optimum curing temperature of the adhesive is determined by the maximum exothermic peak temperature (T) in a Differential Scanning Calorimetry (DSC) curve_p) To determine, the test conditions: n is a radical of₂The environment (50ml/min), the heating rate of 5 ℃/min and the temperature range of 30-350 ℃.

The storage stability of the adhesive is measured by viscosity change, the viscosity is measured by a rotational viscometer under the test conditions that the test temperature is 90 ℃, the rotor speed is 2rpm, and the test time is 1min, the initial viscosity of the adhesive is η₀And a viscosity of η after 30 days of storage_30dIn units of mPa.s^-1(cPs) with viscosity growth ratio η_r＝η_30d/η₀To measure the storage stability of the adhesiveAnd (4) sex.

Glass transition temperature (T) for heat resistance of cured adhesive_g) To measure, T_gThe sample size was 35 × 15 × 2mm, as determined by the peak temperature of the loss factor in the dynamic thermomechanical analysis (DMA) curve³The heating rate is as follows: 5 ℃/min, frequency: 1 Hz.

Dielectric constant (D) for dielectric properties of cured adhesive_k) And dielectric loss tangent (D)_f) The measurement frequency is 1MHz, and the sample size is 50 × 50 × 2mm³。

Example 1

Weighing 100g of bisphenol A cyanate ester, fully melting at 125-130 ℃, cooling to 80-85 ℃, uniformly mixing until the mixture is transparent, and then adding 0.05g of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 1.

Example 2

Weighing 100g of bisphenol A cyanate ester, fully melting at 125-130 ℃, adding 2.5g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, and adding 0.05g of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 1.

Example 3

Weighing 100g of bisphenol A cyanate ester, fully melting at 125-130 ℃, cooling to 80-85 ℃, adding 2.5g of naphthoic acid, uniformly stirring, and adding 0.05g of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 1.

Example 4

Weighing 100g of bisphenol A cyanate ester, fully melting at 125-130 ℃, cooling to 80-85 ℃, adding 2.5g of p-nitrobenzoic acid, uniformly stirring, and adding 0.05g of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 1.

TABLE 1 Effect of different modifier classes on cyanate ester Properties

Examples 1 to 4 reflect the effect of different nitrophenol species on cyanate modification. As can be seen from Table 1, each modifier has a certain promoting effect on the curing of cyanate ester, and the heat resistance and dielectric properties of the final product are high, wherein: the viscosity increase ratio of naphthoic acid to paranitrobenzoic acid is relatively low, which shows that cyanate modified by the two modifiers has good storage stability, and shows that the reaction speed of the two modifiers and cyanate is slow.

Example 5

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 0.5g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 0.5g of naphthoic acid and 0.5g of p-nitrobenzoic acid, stirring uniformly, and adding 0.05g of cobalt acetylacetonate (Co, Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 6

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 0.5g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 1g of naphthoic acid and 1g of p-nitrobenzoic acid, stirring uniformly, and adding 0.1g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 7

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 0.5g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 2g of naphthoic acid and 2g of p-nitrobenzoic acid, stirring uniformly, and adding 0.2g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 8

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 1g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 0.5g of naphthoic acid and 1g of p-nitrobenzoic acid, stirring uniformly, and adding 0.2g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 9

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 1g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 1g of naphthoic acid and 2g of p-nitrobenzoic acid, stirring uniformly, and adding 0.05g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 10

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 1g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 2g of naphthoic acid and 0.5g of p-nitrobenzoic acid, stirring uniformly, and adding 0.1g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 11

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 2g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 0.5g of naphthoic acid and 2g of p-nitrobenzoic acid, stirring uniformly, and adding 0.1g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 12

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 2g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 1g of naphthoic acid and 0.5g of p-nitrobenzoic acid, stirring uniformly, and adding 0.2g of cobalt acetylacetonate (Co)³⁺). And (3) fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 2.

Example 13

Weighing 100g of bisphenol A cyanate, fully melting at 125-130 ℃, adding 2g of benzoic acid, stirring until the mixture is transparent, cooling to 80-85 ℃, adding 2g of naphthoic acid and 1g of p-nitrobenzoic acid, stirring uniformly, and adding 0.05g of cobalt acetylacetonate (Co)³⁺). After the mixture is fully stirred and evenly mixed,and preparing the cyanate adhesive. Specific properties are shown in table 2.

TABLE 2 Effect of different modifier combinations on cyanate ester Properties

Examples 5 to 13 reflect the modification effects of different proportions of benzoic acid, naphthoic acid, paranitrobenzoic acid, and cobalt acetylacetonate on cyanate. As can be seen from Table 2, the three modifiers have better effect when being compounded than any one of 1#, 2# and 3# when being used independently, the lowest curing temperature can reach 152 ℃, which shows that the modifiers generate synergistic action and have better heat resistance and dielectric property.

In addition, when the content of the modifier is moderate, the curing temperature of the cyanate is lower, the storage stability of the cyanate is improved, η_rOnly 1.3 and 1.4, and solves the problem that the storage stability of the cyanate can be greatly reduced by the modifier in the prior art.

The beneficial effects of the invention are better demonstrated in the following comparative tests with known modifiers:

comparative example 1

Weighing 100g of bisphenol A cyanate, fully melting at 110-115 ℃, cooling to 80-85 ℃, adding 2g of bisphenol A, uniformly mixing until the mixture is transparent, and then adding 0.05g of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to prepare a cyanate ester adhesive reference sample. Specific properties are shown in table 3.

Comparative example 2

Weighing 100g of bisphenol A cyanate, fully melting at 110-115 ℃, cooling to 80-85 ℃, adding 2g of bisphenol AF, uniformly mixing until the mixture is transparent, and then adding 0.5 per mill of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to prepare a cyanate ester adhesive reference sample. Specific properties are shown in table 3.

Comparative example 3

Weighing 100g of bisphenol A cyanate, fully melting at 110-115 ℃, cooling to 80-85 ℃, adding 2g of nonyl phenol, uniformly mixing until the mixture is transparent, and then adding 0.5 per mill of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to prepare a cyanate ester adhesive reference sample. Specific properties are shown in table 3.

Comparative example 4

Weighing 100g of bisphenol A cyanate, fully melting at 100-120 ℃, cooling to 80-90 ℃, adding 1.8g of hydroquinone, 1.8g of phloroglucinol and 1.8g of 1,3, 5-benzene trimethyl alcohol, uniformly mixing until the mixture is transparent, and then adding 0.5 per mill of cobalt acetylacetonate (Co)³⁺) And fully stirring and uniformly mixing to obtain the cyanate adhesive. Specific properties are shown in table 3.

TABLE 3 comparison of the Effect of different modifier classes on cyanate ester adhesive Performance

As can be seen from table 3, bisphenol AF, bisphenol a, nonylphenol, and phenol modifiers can all reduce the curing temperature of the cyanate ester adhesive and accelerate the curing speed, but at the same time, the storage stability of the cyanate ester adhesive is seriously reduced.

In the invention, when the naphthoic acid and the p-nitrobenzoic acid are independently added, the curing temperature of the cyanate is reduced, the storage stability is good, and when the naphthoic acid, the naphthoic acid and the p-nitrobenzoic acid are simultaneously added, the curing temperature is further reduced, which shows that the benzoic acid, the naphthoic acid and the p-nitrobenzoic acid can be synergistically used for further reducing the curing temperature of the cyanate. When the benzoic acid, the naphthoic acid and the paranitrobenzoic acid are used in specific amounts, the curing temperature of the cyanate can be reduced, and the storage stability of the cyanate is almost not influenced.

According to the invention, the benzoic acid, the naphthoic acid, the p-nitrobenzoic acid and the cobalt acetylacetonate are added into the cyanate ester in a compounding manner, so that the prepared cyanate ester adhesive has the advantages of good storage stability, low curing temperature, low dielectric constant and dielectric loss, good heat resistance, simple preparation process, low equipment requirement, low production cost and environmental friendliness.

The upper and lower limits and interval values of the raw materials and the upper and lower limits and interval values of the process parameters can all realize the invention, and examples are not listed here.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The cyanate ester adhesive with low curing temperature and high storage stability is characterized by comprising cyanate ester resin, a modifier and a transition metal catalyst;

2. The cyanate ester adhesive with low curing temperature and high storage stability according to claim 1, wherein the modifier and the transition metal catalyst are used in the following amounts: adding 1.5-5 g of modifier and 0.05-0.2 g of transition metal catalyst into every 100g of cyanate ester resin; preferably, 1.5-2.5 g of modifier and 0.05-0.1 g of transition metal catalyst are added to 100g of cyanate ester resin.

3. The cyanate ester adhesive with low curing temperature and high storage stability as claimed in claim 1 or 2, wherein the modifier is a mixture of benzoic acid, naphthoic acid and p-nitrobenzoic acid.

4. The cyanate ester adhesive with low curing temperature and high storage stability as claimed in claim 3, wherein 0.5-2 g of benzoic acid, 0.5-2 g of naphthoic acid and 0.5-2 g of p-nitrobenzoic acid are added to 100g of cyanate ester resin.

5. The cyanate ester adhesive with low curing temperature and high storage stability as claimed in claim 4, wherein 0.5g of benzoic acid, 0.5-1 g of naphthoic acid, and 0.5-1 g of p-nitrobenzoic acid are added to 100g of cyanate ester resin.

6. The cyanate ester adhesive with low curing temperature and high storage stability as claimed in claim 5, wherein the amount of benzoic acid, naphthoic acid, p-nitrobenzoic acid is selected from one of the following:

7. The cyanate ester adhesive with low curing temperature and high storage stability as claimed in any one of claims 1 to 6, wherein the organometallic catalyst is cobalt acetylacetonate.

8. The cyanate ester adhesive with low curing temperature and high storage stability according to any one of claims 1 to 7, wherein the cyanate ester resin is bisphenol A cyanate ester.

9. The preparation method of the cyanate ester adhesive with low curing temperature and high storage stability as claimed in any one of claims 1 to 8, is characterized by comprising the following steps:

10. The method according to claim 9, wherein the cyanate ester resin is melted at a temperature of 100 to 120 ℃, preferably 110 to 115 ℃.

Further, the temperature of the mixture in the step (1) or the step (2) is 80-85 ℃.