CN113528071B - A kind of low dielectric epoxy adhesive and preparation method thereof - Google Patents

Abstract

A low-dielectric epoxy adhesive and a preparation method thereof belong to the field of adhesives. The technical problem to be solved by the present invention is to improve the dielectric properties of the adhesive. The present invention is made of cyanate resin, epoxy resin A, diluent, toughening agent, thixotropic agent, filler, epoxy resin B and catalyst, and the parts by weight are respectively 10-40 parts of cyanate resin, 90 parts by weight ～60 parts epoxy resin A, 0～5 parts epoxy diluent, 5～30 parts toughening agent, 0～10 parts thixotropic agent, 0～140 parts filler, 5～10 parts epoxy resin B, 0.5～ 5 parts catalyst. In the present invention, epoxy resin is used as the main resin, a small amount of cyanate is added for modification, and a non-metallic compound is used as a catalyst to prepare a cyanate-modified epoxy resin paste (paste) adhesive, which has low dielectric properties. Electrical constant and low dielectric loss tangent tanδ, excellent adhesion properties, high peel strength and heat resistance.

Description

A kind of low dielectric epoxy adhesive and preparation method thereof

technical field

The invention belongs to the field of adhesives, and particularly relates to a low-dielectric epoxy adhesive and a preparation method thereof.

Background technique

Low-dielectric epoxy resins and adhesives are widely used in printed circuit boards, low-dielectric composite materials and other fields. The dielectric constant ε of epoxy resin and adhesive under high frequency condition (10GHz) is 3.0～3.4, and the dielectric loss tangent tanδ is 0.010～0.030. The high dielectric constant and dielectric loss of the commonly used epoxy adhesive cannot meet the requirements.

The main methods for improving the dielectric properties of epoxy resins are as follows: First, optimize the curing process, improve the curing degree of the material, make the resin form a more uniform network structure, and effectively limit the polar groups in the structure. The second is to hybridize with low-dielectric inorganic materials, such as silicon dioxide, silsesquioxane, etc.; the third is to blend or copolymerize with low-dielectric polymers.

Cyanate resin is an important modifier of epoxy resin. Cyanate resin is a relatively new type of thermosetting resin, with low moisture absorption, low dielectric constant (2.7 ~ 3.2, 10GHz) and low dielectric loss tangent tanδ (0.004 ~ 0.010, 10GHz) and good excellent flame retardancy, making it an attractive composite resin matrix. Therefore, cyanate-modified epoxy resins (CE/EP) can improve the properties of epoxy resins, and the copolymers are more cost-effective than cyanate esters alone. Cyanate ester/epoxy formulations (containing catalysts, fillers, coupling agents, etc.) are reported to have excellent moisture and thermal shock resistance. It can be used as an underfill material for chip semiconductor devices. The patented formulation has good filling, crack resistance in thermal cycling and good moisture resistance [JP11106,481, JP11106,480], and the application of cyanate ester/epoxy resin is mostly in copper clad laminates [JP7639770, JP85125661, JP1154886], aircraft structure [UP5045609] and semiconductor devices [UP5855821]. Chinese patent CN106753218A discloses a low-dielectric and high-toughness cyanate ester adhesive. The cyanate ester is modified by bisphenol AF epoxy resin. 200°C. Patent ZL201210187060.X discloses a low temperature curing cyanate ester adhesive, and the catalyst is a mixture of phenolic compound and transition metal complex. Chinese patent CN106381110A adopts isocyanate-modified epoxy resin. Different from the matrix resin of this patent, the content of the patent has no dielectric data. The curing agent in Chinese patent CN112080111A is a phenolic compound, which participates in the copolymerization reaction of cyanate ester functional group and epoxy functional group.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a low-dielectric epoxy adhesive with excellent dielectric properties, high adhesive properties and high peel strength and a preparation method thereof.

The present invention is achieved through the following technical solutions:

A low-dielectric epoxy adhesive, the low-dielectric epoxy adhesive is mainly composed of cyanate resin, epoxy resin A, diluent, toughening agent, thixotropic agent, filler, epoxy resin B , the catalyst is made, and its parts by weight are respectively 10-40 parts of cyanate resin, 90-60 parts of epoxy resin A, 0-5 parts of epoxy diluent, 5-30 parts of toughening agent, 0-10 parts of epoxy resin Thixotropic agent, 0-140 parts of filler, 5-10 parts of epoxy resin B, 0.5-5 parts of catalyst.

In the low dielectric epoxy adhesive of the present invention, the cyanate resin is bisphenol A cyanate, bisphenol A cyanate prepolymer, bisphenol E cyanate, bisphenol M cyanate One or a combination of esters, phenolic cyanate, dicyclopentadiene cyanate and cardanol cyanate resin.

In the low-dielectric epoxy adhesive of the present invention, the epoxy resin A is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol A One of the diglycidyl ether of phenol F and the trifunctional glycidyl amine or a mixture of several of them, and the epoxy equivalent weight is 100-240 g/eq.

In the low-dielectric epoxy adhesive of the present invention, the diluent is dipropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, resorcinol diglycidyl ether, ethylene glycol One or more mixtures of alcohol diglycidyl ethers.

In the low-dielectric epoxy adhesive of the present invention, the toughening agent is rubber particles with a core-shell structure, and the toughening agent is commercially available S-2001, EXL2691, S-2006, S- One or more mixtures of 2030, SX-005, SX-006, MR-501, P52, and EXL2330.

In the low-dielectric epoxy adhesive of the present invention, the thixotropic agent is one or a mixture of fumed silica and surface-treated fumed silica.

In the low-dielectric epoxy adhesive according to the present invention, the filler is fused spherical silica micropowder, and the average particle size of the filler is D ₉₅ ≤15 microns.

In the low-dielectric epoxy adhesive of the present invention, the epoxy resin B is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol A One of the diglycidyl ether of phenol F and the trifunctional glycidyl amine or a mixture of several of them, and the epoxy equivalent weight is 100-240 g/eq.

In the low-dielectric epoxy adhesive of the present invention, the catalyst is a combination of one or more of 2-methylimidazole, 1-methylimidazole and 2-ethyl-4-methylimidazole.

The preparation method of a low-dielectric epoxy adhesive according to the present invention comprises the following steps:

Step 1: Weigh 10-40 parts by weight of cyanate resin, add 90-60 parts by weight of epoxy resin A and stir evenly, 0-5 parts by weight of epoxy diluent, add 5-30 parts by weight of toughening agent, 0-10 parts by weight parts by weight of a thixotropic agent and 0-140 parts by weight of fillers to obtain a resin in step 1, which is ready for use;

Step 2: Weigh 5-10 parts of epoxy resin B, add 0.5-5 parts of catalyst, and mix evenly to obtain step 2 resin, which is ready for use;

Step 3: Mix the resin in the first step with the resin in the second step, and stir evenly to prepare the low-dielectric epoxy adhesive.

In the low-dielectric epoxy adhesive of the present invention, epoxy resin is modified with cyanate ester and non-metallic compound, and toughening agent, thixotropic agent and filler are added, and the copolymerization reaction route of cyanate ester and epoxy resin is as follows: The cyanate ester undergoes self-polymerization reaction to form a triazine ring structure, and the epoxy group is inserted into the triazine ring to isomerize to isocyanurate, and then the structure rearranges into an oxazolidinone structure. In addition to self-polymerization to form a triazine ring structure, the cyanate functional group can also form a four-membered ring dimer. There are more quaternary ring dimer structures in the cyanate/epoxy resin system catalyzed by phenol/transition metal complexes, while there are more isocyanurate ring structures in the non-metal ion catalyzed resin system. The addition of catalysts usually affects the formation mechanism of the mixed network and changes the material properties. Therefore, compared with the prior art, the present invention is characterized in that the cyanate ester-modified epoxy resin paste (paste)-like glue has low dielectric constant and low dielectric loss tangent tanδ, excellent adhesion performance, High peel strength and heat resistance, and good process performance, can be used for low dielectric cyanate, double horse composite bonding and repair.

The low-dielectric epoxy adhesive of the present invention uses epoxy resin as the main resin, adds a small amount of cyanate ester for modification, and uses a non-metallic compound as a catalyst to prepare a cyanate ester-modified epoxy resin paste ( Paste)-like adhesive has lower dielectric constant and low dielectric loss tangent tanδ, higher room temperature and high temperature bonding strength.

Detailed ways

Specific implementation one:

A preparation method of low-dielectric epoxy adhesive, comprising the following steps:

Step 1. Weigh 50 parts of bisphenol F epoxy resin and 40 parts of bisphenol E cyanate by parts by weight, and blend them evenly;

Step 2: Weigh 10 parts of bisphenol F epoxy resin by mass, add 1 part of 2-ethyl-4-methylimidazole, and stir evenly;

Step 3: Mix the resins of Step 1 and Step 2 uniformly to prepare a low-dielectric epoxy adhesive.

A low-dielectric epoxy adhesive prepared in this embodiment is used for dielectric samples, the sample size is φ25mm×2mm, and the curing process is cured at 100°C for 12 hours, and then cured at 150°C for 12 hours.

Comparative Example 1: The catalyst was a mixture of 4 parts of nonylphenol and 0.0666 parts of copper acetylacetonate by weight, and the others were the same as in the first embodiment.

Specific implementation two:

A preparation method of low-dielectric epoxy adhesive, comprising the following steps:

Step 1: Weigh 50 parts of bisphenol F epoxy resin and 40 parts of bisphenol E cyanate by weight, mix them evenly, then add 20 parts of EXL2691 core-shell particles, and in a high-speed disperser at 5000～13000r/ min speed dispersion 3 ~ 10min;

Step 2: Weigh 10 parts of bisphenol F epoxy resin by weight, add 1 part of 2-ethyl-4-methylimidazole, and stir evenly;

Step 3: Mix the resins of Step 1 and Step 2 uniformly to prepare a low-dielectric epoxy adhesive.

A low-dielectric epoxy adhesive prepared in this embodiment is used for dielectric samples, the sample size is φ25mm×2mm, and the test pieces are bonded, and the curing process is cured at 100°C for 12 hours, and then cured at 150°C for 12 hours.

Comparative Example 2: The catalyst was a mixture of 4 parts of nonylphenol and 0.0666 parts of copper acetylacetonate by weight, and the others were the same as in the second embodiment.

Specific implementation three:

A preparation method of low-dielectric epoxy adhesive, comprising the following steps:

Step 1: Weigh 50 parts of bisphenol F epoxy resin and 40 parts of bisphenol E cyanate by weight, mix them uniformly, then add 30 parts of EXL2691 core-shell particles, and in a high-speed disperser, at 10000～13000r/ min speed dispersion 3 ~ 10min;

Step 2: Weigh 10 parts of bisphenol F epoxy resin by weight, add 1 part of 2-ethyl-4-methylimidazole, and stir evenly;

Step 3: Mix the resins of Step 1 and Step 2 uniformly to prepare a low-dielectric epoxy adhesive.

A low-dielectric epoxy adhesive prepared in this embodiment is used for dielectric samples, the sample size is φ25mm×2mm, and the test pieces are bonded, and the curing process is cured at 100°C for 12 hours, and then cured at 150°C for 12 hours.

Comparative Example 3: The catalyst was a mixture of 4 parts of nonylphenol and 0.0666 parts of copper acetylacetonate by weight, and the others were the same as those of the third embodiment.

The shear strength test refers to the HB5164 tensile shear strength test method, and the sample material: 2A12 aluminum alloy. The peel strength test refers to GJB446-88 adhesive 90° peel strength test method, sample material: 2A12 aluminum alloy aluminum alloy. The samples were tested with a dielectric constant tester (Keysight E5071c, USA). Room temperature test, frequency 10.1GHz. The test results are shown in Table 1:

Table 1 Adhesive properties and dielectric properties of adhesives

As can be seen from Table 1, 2-ethyl-4-methyl catalyzed cyanate ester-modified epoxy resin (CE/EP) has higher adhesive strength, especially 150°C shear strength. When the addition amount of core-shell particle EXL2691 increased from 0 to 30 parts by weight, the shear strength at 150°C increased from 26.75MPa to 29.81MPa; the 90° peel strength increased from 17.84N/cm to 60.53N/cm, and the peel strength increased by 42.69N/cm cm. The dielectric constant and dielectric loss tangent tanδ decreased with the increase of core-shell particles EXL2691A, the dielectric constant decreased from 2.88 to 2.71, the dielectric loss tangent value tanδ decreased from 0.01831 to 0.01720, and the dielectric properties improved.

As can be seen from Table 1, the shear strength of the cyanate ester modified epoxy resin catalyzed by the comparative example nonylphenol/copper acetylacetonate is lower. When the addition amount of core-shell particle EXL2691 increased from 0 to 30 parts by weight, the shear strength at 150°C showed a downward trend, from 23.79MPa to 19.0MPa; the 90° peel strength increased from 13.52N/cm to 44.04N/cm, and the peel strength was only Increased by 30.52N/cm. The dielectric constant of the cured adhesive increased from 2.74 to 2.82, the dielectric loss tangent tanδ increased from 0.01750 to 0.01808, and the dielectric properties deteriorated.

In summary, the non-metallic catalyst and core-shell particle EXL2691A modified CE/EP can improve the adhesion performance of the cyanate ester adhesive and further ensure the dielectric performance of the low-dielectric epoxy adhesive.

Specific implementation four:

A preparation method of low-dielectric epoxy adhesive, comprising the following steps:

Step 1. Weigh 50 parts of bisphenol F epoxy resin, 30 parts of bisphenol E cyanate ester, and 10 parts of bisphenol A cyanate ester prepolymer by weight, mix them evenly, and then add 20 parts of p52 core-shell particles. parts, 2 parts of fumed silica, disperse in a high-speed disperser at a speed of 5000-13000r/min for 3-10min;

Step 2: Weigh 10 parts of bisphenol F epoxy resin by weight, add 1 part of 2-ethyl-4-methylimidazole, and stir evenly;

Step 3: Mix the resins of Step 1 and Step 2 uniformly to prepare a low-dielectric epoxy adhesive.

A low-dielectric epoxy adhesive prepared in this embodiment is used for dielectric samples, the sample size is φ25mm×2mm, and the test pieces are bonded, and the curing process is cured at 100°C for 12 hours, and then cured at 150°C for 12 hours.

Specific implementation five:

A preparation method of low-dielectric epoxy adhesive, comprising the following steps:

Step 1: Weigh 50 parts of bisphenol F epoxy resin, 30 parts of bisphenol E cyanate ester, and 10 parts of bisphenol A cyanate ester prepolymer by weight, mix them evenly, and then add 30 parts of p52 core-shell particles parts, 2 parts of fumed silica, disperse in a high-speed disperser at a speed of 5000-13000r/min for 3-10min;

Step 2: Weigh 10 parts of bisphenol F epoxy resin by mass, add 1 part of 2-ethyl-4-methylimidazole, and stir evenly;

Step 3: Mix the resins of Step 1 and Step 2 uniformly to prepare a low-dielectric epoxy adhesive.

A low-dielectric epoxy adhesive prepared in this embodiment is used for dielectric samples, the sample size is φ25mm×2mm, and the test pieces are bonded, and the curing process is cured at 100°C for 12 hours, and then cured at 150°C for 12 hours.

The performance test of a kind of low dielectric epoxy adhesive prepared by specific embodiment four and specific embodiment five is shown in Table 2:

Table 2 Shear strength, bond strength and dielectric properties of adhesives

It can be seen from Table 2 that the 2-ethyl-4-methylimidazole and the organosilicon core-shell particle P52 in the low-dielectric epoxy adhesive are mutually coordinated and can produce a synergistic effect. As the amount of core-shell particles increases, the bonding strength increases and the dielectric constant decreases.

Specific implementation six:

A preparation method of low-dielectric epoxy adhesive, comprising the following steps:

Step 1: Weigh 60 parts of bisphenol F epoxy resin, 30 parts of bisphenol E cyanate ester, and 5 parts of ethylene glycol diglycidyl ether by weight, mix them evenly, and then add 10 parts of EXL2691 core-shell particles, Disperse in a high-speed disperser, the dispersing speed is 10000～13000r/min, and the dispersing time is 3～10min, then add 100 parts of silicon micropowder and 4 parts of fumed silica, and disperse on a high-speed mixer at a speed of 1000～2000r/min 30～60min;

Step 2: Weigh 5 parts of bisphenol F epoxy resin by weight, add 1 part of 2-ethyl-4-methylimidazole, and stir evenly;

Step 3: Mix the resins of Step 1 and Step 2 uniformly to prepare a low-dielectric epoxy adhesive.

A low-dielectric epoxy adhesive prepared in this embodiment is used for dielectric samples, the sample size is φ25mm×2mm, and the test pieces are bonded, and the curing process is cured at 100°C for 12 hours, and then cured at 150°C for 12 hours.

For a low-dielectric epoxy adhesive prepared in this embodiment, a dielectric constant tester (Keysight E5071c, USA) is used to test the sample. The room temperature test, the frequency range is 2 ~ 18.3GHz, the test results are shown in Table 3:

Table 3 Dielectric constant and dielectric loss tangent tanδ of adhesives

Frequency/GHz Dielectric constant Dielectric loss tangent tanδ 2 2.75 0.00890 6 2.73 0.00808 10.1 2.72 0.00787 14.2 2.71 0.00623 18.3 2.70 0.00454

It can be seen from Table 3 that in the modified epoxy adhesive catalyzed by non-metallic compounds, adding silicon micropowder can further effectively reduce the dielectric constant and dielectric loss tangent tanδ of the adhesive, the dielectric constant is reduced to 2.70-2.75, and the dielectric constant is reduced to 2.70-2.75. The electrical loss tangent tanδ is reduced to 0.00454～0.00890.

Specific implementation seven:

A low-dielectric epoxy adhesive, the low-dielectric epoxy adhesive is mainly composed of cyanate resin, epoxy resin A, diluent, toughening agent, thixotropic agent, filler, epoxy resin B , the catalyst is made, and its parts by weight are respectively 10-40 parts of cyanate resin, 90-60 parts of epoxy resin A, 0-5 parts of epoxy diluent, 5-30 parts of toughening agent, 0-10 parts of epoxy resin Thixotropic agent, 0-140 parts of filler, 5-10 parts of epoxy resin B, 0.5-5 parts of catalyst.

In the low dielectric epoxy adhesive described in this embodiment, epoxy resin is modified with cyanate ester and non-metallic compound, toughening agent, thixotropic agent and filler are added, and the copolymerization reaction route of cyanate ester and epoxy It is the self-polymerization reaction of cyanate ester to form a triazine ring structure, the epoxy group is inserted into the triazine ring to isomerize to isocyanurate, and then the structure rearranges into an oxazolidinone structure. In addition to self-polymerization to form a triazine ring structure, the cyanate functional group can also form a four-membered ring dimer. There are more quaternary ring dimer structures in the cyanate/epoxy resin system catalyzed by phenol/transition metal complexes, while there are more isocyanurate ring structures in the non-metal ion catalyzed resin system. The addition of catalysts usually affects the formation mechanism of the mixed network and changes the material properties. Therefore, compared with the prior art, the present embodiment has the characteristics of a cyanate ester modified epoxy resin paste adhesive, with low dielectric constant and low dielectric loss tangent tanδ, excellent adhesion performance, high peeling Strength and heat resistance, and good process performance, can be used for low dielectric cyanate ester, double horse composite bonding and repair.

The low-dielectric epoxy adhesive of the present invention uses epoxy resin as the main resin, adds a small amount of cyanate ester for modification, and uses a non-metallic compound as a catalyst to prepare a cyanate ester-modified epoxy resin paste ( Paste)-like adhesive has lower dielectric constant and low dielectric loss tangent tanδ, higher room temperature and high temperature adhesive strength

Eighth specific implementation:

According to the low-dielectric epoxy adhesive described in Embodiment 7, the cyanate resin is bisphenol A cyanate, bisphenol A cyanate prepolymer, bisphenol E cyanate, bisphenol A cyanate One or a combination of phenol M cyanate, novolac cyanate, dicyclopentadiene cyanate and cardanol cyanate resin.

Specific implementation nine:

According to the low-dielectric epoxy adhesive according to the seventh embodiment, the epoxy resin A is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and diglycidyl ether of hydrogenated bisphenol A , Diglycidyl ether of hydrogenated bisphenol F, trifunctional glycidyl amine or a mixture of several of them, and the epoxy equivalent is 100-240 g/eq.

Specific implementation ten:

A kind of low dielectric epoxy adhesive according to the seventh embodiment, the diluent is dipropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, resorcinol diglycidyl ether , one or more mixtures of ethylene glycol diglycidyl ether.

Specific implementation eleven:

According to the low-dielectric epoxy adhesive according to Embodiment 7, the toughening agent is rubber particles with a core-shell structure, and the toughening agent is commercially available S-2001, EXL2691, S-2006 , S-2030, SX-005, SX-006, MR-501, P52, one or more mixtures of EXL2330.

Twelve specific implementations:

According to the low-dielectric epoxy adhesive of Embodiment 7, the thixotropic agent is one or a mixture of fumed silica and surface-treated fumed silica.

Specific implementation thirteen:

According to the low-dielectric epoxy adhesive according to Embodiment 7, the filler is fused spherical silica micropowder, and the average particle size D ₉₅ of the filler is ≤15 microns.

Specific implementation fourteen:

According to the low-dielectric epoxy adhesive according to the seventh embodiment, the epoxy resin B is bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and diglycidyl ether of hydrogenated bisphenol A , Diglycidyl ether of hydrogenated bisphenol F, trifunctional glycidyl amine or a mixture of several of them, and the epoxy equivalent is 100-240 g/eq.

Specific implementation fifteen:

According to a kind of low dielectric epoxy adhesive according to the seventh embodiment, the catalyst is one or more of 2-methylimidazole, 1-methylimidazole and 2-ethyl-4-methylimidazole combination.

Specific implementation sixteen:

The preparation method of a kind of low-dielectric epoxy adhesive according to the seventh embodiment, comprising the following steps:

Step 1: Weigh 10-40 parts by weight of cyanate resin, add 90-60 parts by weight of epoxy resin A and stir evenly, 0-5 parts by weight of epoxy diluent, add 5-30 parts by weight of toughening agent, 0-10 parts by weight parts by weight of a thixotropic agent and 0-140 parts by weight of fillers to obtain a resin in step 1, which is ready for use;

Step 2: Weigh 5-10 parts of epoxy resin B, add 0.5-5 parts of catalyst, and mix evenly to obtain step 2 resin, which is ready for use;

Step 3: Mix the resin in the first step with the resin in the second step, and stir evenly to prepare the low-dielectric epoxy adhesive.

Claims (7)

1. A low dielectric epoxy adhesive is characterized in that: the low-dielectric epoxy resin is mainly prepared from 10-40 parts by weight of cyanate ester resin, 90-60 parts by weight of epoxy resin A, 0-5 parts by weight of epoxy diluent, 5-30 parts by weight of toughening agent, 0-10 parts by weight of thixotropic agent, 0-140 parts by weight of filler, 5-10 parts by weight of epoxy resin B and 0.5-5 parts by weight of catalyst;

the toughening agent is rubber particles with a core-shell structure, and is one or a mixture of more of commercially available S-2001, EXL2691, S-2006, S-2030, SX-005, SX-006, MR-501, P52 and EXL 2330;

the epoxy resin B is one or a mixture of more of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether and trifunctional glycidyl amine, and the epoxy equivalent is 100-240 g/eq;

the catalyst is one or a combination of 2-methylimidazole, 1-methylimidazole and 2-ethyl-4-methylimidazole.

2. The low dielectric epoxy adhesive of claim 1, wherein: the cyanate resin is one or a combination of bisphenol A cyanate, bisphenol A cyanate prepolymer, bisphenol E cyanate, bisphenol M cyanate, phenolic cyanate, dicyclopentadiene cyanate and cardanol cyanate resin.

3. The low dielectric epoxy adhesive of claim 1 or 2, wherein: the epoxy resin A is one or a mixture of more of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether and trifunctional glycidyl amine, and the epoxy equivalent is 100-240 g/eq.

4. The low dielectric epoxy adhesive of claim 3, wherein: the diluent is one or a mixture of more of dipropylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, resorcinol diglycidyl ether and ethylene glycol diglycidyl ether.

5. The low dielectric epoxy adhesive of claim 4, wherein: the thixotropic agent is one or a mixture of more of fumed silica and surface-treated fumed silica.

6. The low dielectric epoxy adhesive of claim 5, wherein: the filler is fused spherical silicon micropowder, and the average particle diameter D of the filler ₉₅ Less than or equal to 15 microns.

7. A method for preparing a low dielectric epoxy glue according to any of claims 1 to 6, characterized in that: the method comprises the following steps:

weighing 10-40 parts by weight of cyanate ester resin, adding 90-60 parts by weight of epoxy resin A, uniformly stirring, adding 0-5 parts by weight of epoxy diluent, adding 5-30 parts by weight of toughening agent, 0-10 parts by weight of thixotropic agent and 0-140 parts by weight of filler, and obtaining the resin in the first step for later use;

step two, weighing 5-10 parts of epoxy resin B, adding 0.5-5 parts of catalyst, and uniformly mixing to obtain resin in step two for later use;

and step three, mixing the resin obtained in the step one with the resin obtained in the step two, and uniformly stirring to obtain the low dielectric epoxy glue.