CN116004159B - Underfill applicable to intelligent automobile and preparation method thereof - Google Patents

Abstract

The invention relates to an underfill adhesive suitable for an intelligent automobile, which comprises the following raw materials in parts by mass: 15-20 parts of dicyclopentadiene type epoxy resin, 6-8 parts of triglycidyl para-aminophenol (AFG-90), 8-11 parts of polyfunctional epoxy resin, 45-55 parts of modified spherical silica micropowder, 20-26 parts of anhydride type epoxy curing agent and 3-5 parts of curing accelerator; the polyfunctional epoxy resin is pentaerythritol and/or derivatives thereof, and is prepared by performing esterification reaction with sulfhydryl polyethylene glycol carboxyl, and then performing click reaction with alkenyl-containing glycidyl ether to generate sulfhydryl-alkenyl; the modified spherical silicon micro powder is obtained by modifying spherical silicon micro powder through an epoxy silane coupling agent and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide. The underfill disclosed by the invention has excellent comprehensive performance, high fluidity, low thermal expansion coefficient, high bonding strength to a PCB substrate and excellent aging resistance.

Description

Underfill applicable to intelligent automobile and preparation method thereof

Technical Field

The invention belongs to the field of semiconductor adhesives, and particularly relates to an underfill adhesive suitable for an intelligent automobile and a preparation method thereof.

Background

With the high-speed development of automatic driving or advanced auxiliary driving systems in recent years, parts such as vehicle cameras, millimeter wave radars, laser radars and the like, voice systems, automatic navigation systems and the like are used as core sensing devices of automobiles, and the development of intellectualization and miniaturization is advanced. Some of the chips in these components, such as BGA, CSP, etc., have an increasing number of fine pitch matrix devices due to their higher integration, and the continuous vibration of the vehicle itself during long driving and the need to face severe high and low temperature effects have an increasing probability of failure of the chips in these sensing devices. Since the BGA chip has a problem of reliability due to stress concentration, it is necessary to underfill the BGA in order to provide the BGA package with higher mechanical reliability. The underfill fills the gap between the PCB substrate and the BGA package, provides a mechanical connection function, and absorbs mechanical stress in the impact or drop process; and the underfill can effectively protect welding spots from moisture, ion pollutants and the like, so that the electronic device keeps good firm stability, and the correct selection of the underfill has great influence on the reliability of the product.

As an underfill for a smart car, in addition to the requirement of a conventional underfill, better vibration resistance and high and low temperature resistance are required. Compared with traditional consumer electronic products such as mobile phones, tablets and the like, the service life and stability of automobile electronic products are common industry pain points. The working temperature range of the notebook computer is generally between 0 and 50 ℃, and the working temperature of the mobile phone is not more than 70 ℃. The conventional operating temperature range of the vehicle-mounted equipment can range from-40 ℃ in winter, such as extremely cold regions, to the extreme operating temperature of electronic components in the engine under long-term sunlight exposure in summer, such as desert regions, and even reach more than 100 ℃. In general, when an automobile component works, the temperature and humidity of the outside are often changed, external mechanical impact, mechanical vibration and the like are often caused, and the temperature and humidity change and the mechanical stress can act on a chip, so that the chip is invalid. The chip bottom filling glue can effectively absorb the stresses, so that the long-term reliability of the chip is improved, and the chip bottom filling glue becomes an important solution for protecting vehicle-mounted electronic components.

In addition, for the current new energy automobile manufacturers, the vehicle-mounted auxiliary driving system has excellent fluidity of the underfill, while ensuring the performance of the glue as much as possible in order to meet the high production line production efficiency, although the fluidity of the underfill is not as high as that of consumer electronic products such as mobile phones and computers.

At present, the domestic research on the underfill which is suitable for the automobile auxiliary system is still blank. Hansi chemical develops a series of underfill which is suitable for intelligent automobiles and improves the anti-falling performance of the product. But still further improvement in terms of aging resistance

Disclosure of Invention

In order to solve the problem that the prior art is lack of underfill specially aiming at auxiliary electronic systems of intelligent automobiles, the invention provides the underfill which has high fluidity, low thermal expansion coefficient, anti-drop performance and excellent aging resistance and is suitable for the intelligent automobiles. The chip of an Advanced Driving Assistance (ADAS) system can be effectively protected, the reliability and stability of the vehicle assistance system are improved, and the vehicle assistance system can withstand severe high-humidity, high-low temperature circulation and impact environment. The intelligent automobile electronic system can stably run, and the safety and reliability of the intelligent automobile are improved.

The aim of the invention is solved by the following technical scheme:

the underfill adhesive suitable for the intelligent automobile comprises the following raw materials in parts by mass: 15-20 parts of dicyclopentadiene type epoxy resin, 6-8 parts of triglycidyl para-aminophenol (AFG-90), 8-11 parts of polyfunctional epoxy resin, 45-55 parts of modified spherical silica micropowder, 20-26 parts of anhydride type epoxy curing agent and 3-5 parts of curing accelerator; the polyfunctional epoxy resin is pentaerythritol and/or derivatives thereof, and is prepared by performing esterification reaction with sulfhydryl polyethylene glycol carboxyl, and then performing click reaction with alkenyl-containing glycidyl ether to generate sulfhydryl-alkenyl; the modified spherical silicon micro powder is obtained by modifying spherical silicon micro powder through an epoxy silane coupling agent and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide.

The inventor's prior patent CN202211575925.X discloses a underfill with high flowability and low thermal expansion coefficient, which is mainly prepared by compounding bisphenol F epoxy resin and high-functionality epoxy resin, so as to achieve high flowability and low thermal expansion. But the strength and the aging resistance of the intelligent automobile are still to be further improved when the intelligent automobile is applied to the severe use environment of the intelligent automobile. In underfill, a relatively large amount of spherical silica powder is generally added to reduce the thermal expansion coefficient of the glue. When the proportion of the spherical silica powder in the system is large, agglomeration is easy to generate, the dispersibility is poor, the compatibility of matrix resin is poor, and the impact resistance and the aging resistance of the device are not good under the condition of more addition. The present application is further optimized on the basis of this patent so that it is suitable for use as an underfill for intelligent automobiles.

Further, the dicyclopentadiene type epoxy resin has an epoxy equivalent weight of 250 to 270g/eq.

Further, the modified spherical silica micropowder is prepared by a preparation method comprising the following steps: dispersing spherical silicon powder in a solvent, adding an epoxy silane coupling agent and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide, reacting for 5-10h under the stirring condition of 60-80 ℃, carrying out suction filtration, washing and drying to obtain modified spherical silicon micro powder; the solvent is at least one of water, ethanol and isopropanol, and is preferably 60-80vol% ethanol water solution.

Still further, the epoxy silane coupling agent is at least one selected from the group consisting of (3-glycidoxypropyl trimethoxysilane (KH-560), 3- (2, 3-glycidoxypropyl) propyltriethoxysilane (KH-561) and 3- (2, 3-glycidoxypropyl) propylmethyldimethoxysilane (KH-562), and the mass ratio of silicon powder, epoxy silane coupling agent and bis- [3- (triethoxysilane) propyl ] -tetrasulfide is 100:6-9:1-3.

The prior art generally uses a silane coupling agent to modify the silica micropowder to enhance its affinity with the epoxy resin and improve the dispersion state of the silica micropowder, but conventional silane coupling agents such as KH-570 modified silica micropowder, although having an enhanced affinity with the epoxy resin, have unsatisfactory weatherability of an underfill comprising the same. The inventor unexpectedly found that, in addition to the epoxy silane coupling agent, a small amount of bis- [3- (triethoxysilane) propyl ] -tetrasulfide is added during modification, and the prepared modified spherical silica micropowder obviously enhances the impact resistance and weather resistance of the underfill at the same time, so that the underfill has excellent impact resistance and high and low temperature resistant stability, and provides powerful and reliable protection for intelligent automobile electronic components. The modified spherical silica powder is uniformly dispersed in the resin matrix, and when the matrix is impacted, stronger affinity exists between the spherical silica powder and the matrix, so that the defect formation after solidification is reduced, the stress can be effectively transmitted, the cohesive force is improved, the impact energy is absorbed, and the adhesive layer is not broken under the condition of large instantaneous impact strength, so that a good toughening effect is achieved. Therefore, in a certain content range, the modified spherical silica powder can improve the impact resistance of the underfill.

Further, the polyfunctional epoxy resin is prepared by carrying out esterification reaction on pentaerythritol and/or pentaerythritol derivatives and sulfhydryl PEG carboxyl (SH-PEG-COOH) and then carrying out click reaction on the obtained product and alkenyl-containing glycidyl ether; the number of the repeated units of PEG in the sulfhydryl PEG carboxyl is 5-10; the pentaerythritol derivative is selected from dipentaerythritol; the alkenyl-containing glycidyl ether is at least one selected from glycidyl methacrylate and allyl glycidyl ether.

Further, pentaerythritol and/or pentaerythritol derivatives, and the amount of thiol PEG carboxyl groups satisfy the following relationship: the molar ratio of hydroxyl (-OH) in pentaerythritol and/or pentaerythritol derivatives to carboxyl (-COOH) in sulfhydryl PEG carboxyl is 1:1-1.2, preferably 1:1.05-1.1; the mol ratio of the sulfhydryl PEG carboxyl to the alkenyl-containing glycidyl ether is 1:1-1.05, and the sulfhydryl PEG carboxyl and the alkenyl-containing glycidyl ether are equal in quantity.

The polyfunctional epoxy resin is pentaerythritol and/or pentaerythritol derivative, and is first esterified with mercapto PEG carboxyl, and then the mercapto (-SH) of the intermediate product is click reacted with carbon-carbon double bond containing alkenyl glycidyl ether. The reaction conditions are well known in the art. In one specific embodiment of the invention, pentaerythritol and/or pentaerythritol derivatives and sulfhydryl PEG carboxyl are subjected to esterification reaction firstly, and the condition is that in the presence of p-toluenesulfonic acid as a catalyst, heating reflux reaction is carried out, the reaction solvent is at least one of benzene, toluene and petroleum ether, the reaction temperature is 80-110 ℃ (the reaction temperature is determined according to the boiling point of the solvent), after the reaction time is 5-8 hours, the acid value of the reaction system is not reduced, the reaction system is cooled to room temperature, alkali liquor is used for washing, the pH of an organic phase is neutral (pH is 6.8-7.5), the organic phase is separated, and the solvent is removed by rotary evaporation to obtain an intermediate product with a sulfhydryl end group, or the reaction with alkenyl glycidyl ether can be directly carried out without post treatment. The reaction condition of the intermediate product and the glycidyl ether containing alkenyl for click reaction is that the reaction temperature is controlled to be 5-10 ℃, the reaction is carried out for 2-4 hours, the reaction solvent is at least one of benzene, toluene, petroleum ether, chloroform and carbon tetrachloride, at the moment, the vibration peak of the product FT-IR detection, -SH is basically disappeared, the reaction is finished, and the solvent is removed by reduced pressure distillation, so that the colorless liquid is obtained, namely the multifunctional epoxy resin. The multifunctional epoxy resin obtained by the invention takes pentaerythritol and/or dipentaerythritol as a core, a connecting chain is a flexible PEG chain, and a terminal group is an epoxy group. The polyfunctional epoxy resin provided by the invention has low viscosity, does not influence the fluidity of the underfill, has a sufficient toughening effect, and remarkably improves the impact resistance of the underfill.

Further, the anhydride epoxy curing agent is at least one selected from methyl hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, phthalic anhydride and glutaric anhydride.

Further, the curing accelerator is selected from amine accelerators and/or imidazole accelerators, and the amine accelerators are selected from at least one of N, N-dimethylaniline and diethylamine propylamine; the imidazole accelerator is at least one selected from 2-ethyl-4-methylimidazole, 2-butylimidazole, 2-phenyl-4-methylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole.

Further, the D50 of the spherical silica micropowder is 1-10 μm, preferably 1-3 μm. The small particle size of the spherical silica powder is beneficial to the defect of chip bottom filling glue, and the occurrence of blockage and holes in the filling process is avoided.

Preferably, when adding the spherical silica powder, it is added in multiple additions, for example in 2-5 average additions. The average is not the same as the amount of spherical silica powder added each time, and the difference between the amounts added each time is not more than 10%.

Preferably, the underfill applicable to the intelligent automobile provided by the invention further comprises other auxiliary materials. The auxiliary materials are of the types, functions and dosage well known in the art, for example, the bottom filling glue formulation also comprises 0.3-0.5 part of anti-sedimentation agent, 0.5-1 part of color paste, 0.5-1 part of flatting agent, 0.2-0.5 part of toughening agent and 0.05-0.2 part of defoaming agent.

The anti-sedimentation agent is at least one of BYK9010, BYK-995, BYK-306 and BYK-2008; the toughening agent is at least one of dibutyl phthalate and dioctyl phthalate; the defoamer is at least one selected from BYK-320, BYK-322 and BYK-323.

The invention also provides a preparation method of the underfill adhesive suitable for the intelligent automobile, which comprises the following steps:

(S1) uniformly mixing dicyclopentadiene type epoxy resin, triglycidyl para-aminophenol (AFG-90) and polyfunctional epoxy resin to obtain a first mixture;

(S2) dispersing spherical silicon micropowder in a solvent to obtain dispersion, adding an epoxy silane coupling agent and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide, reacting for 10 hours under the stirring condition of 60-80 ℃, filtering, washing and drying to obtain modified spherical silicon micropowder;

(S3) adding the modified spherical silica powder and the curing accelerator into the first mixture, and uniformly mixing; and finally, adding an anhydride epoxy curing agent, uniformly mixing, and carrying out vacuum defoamation on the system to obtain the epoxy resin.

Further, in the preparation of the underfill, other auxiliary materials such as an anti-sedimentation agent, color paste (pigment), a leveling agent, a toughening agent, a defoaming agent and the like are also added. The order of adding the auxiliary materials is not particularly limited, and may be added together with the epoxy resin in step (S1) or with the spherical fine silica powder in step (S3).

The uniform mixing is carried out at a stirring speed of 1500-3000rpm for 5-10min; the vacuum defoaming is carried out under the condition of 0.01-0.1MPa vacuum degree and stirring for 2-5min at 1500-3000 rpm.

The invention has the excellent effects that:

1. according to the invention, the spherical silica micropowder is modified, so that the affinity of the silica micropowder and epoxy resin is enhanced, the dispersibility of the silica micropowder in the adhesive is improved, and the obtained underfill adhesive has obviously improved impact resistance and ageing resistance after being cured.

2. The invention takes pentaerythritol/dipentaerythritol as a core, firstly carries out esterification reaction with mercapto polyethylene glycol carboxyl to obtain an intermediate product with a mercapto end group, then carries out click reaction with alkenyl glycidyl ether to finally obtain the polyfunctional epoxy resin with a PEG chain with a certain length and a chain link, the polyfunctional epoxy resin has low viscosity, does not influence the fluidity of the underfill, but obviously improves the solidification toughness of the underfill, and has good stability.

3. The underfill provided by the invention can achieve good fluidity without using a reactive diluent. In general, in order to achieve better flowability, a reactive diluent is needed to be added to reduce the viscosity of the glue at normal temperature, but even if the reactive diluent is provided with an epoxy group, the introduction of the reactive diluent can participate in the curing reaction, but the mechanical strength and the thermal property of a cured product are inevitably affected.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. The following examples facilitate a better understanding of the present invention, but are not intended to limit the same. The experimental methods in the following examples are conventional methods unless otherwise specified.

Unless otherwise specified, the parts in the embodiment of the invention are all parts by mass, and the percentages are all percentages by mass.

The reagents and equipment used in the present invention, as well as the testing methods, are conventional in the art.

Thiol PEG carboxyl groups (SH-PEG-COOH) were purchased from Jiangsu Kai biological medicine Co., ltd, wherein the average degree of polymerization of PEG was 5 and 10, respectively, and were designated SH-PEG5-COOH (degree of polymerization 5) and SH-PEG10-COOH (degree of polymerization 10), respectively.

Dicyclopentadiene type epoxy resin is purchased from Jining Malus asiatica chemical industry Co., ltd, brand DNE260HA75, epoxy equivalent 260, viscosity 350cps at 25 ℃.

Preparation example 1

1 part of pentaerythritol is dissolved in toluene, 4.2 parts of mercapto PEG carboxyl (SH-PEG 5-COOH) with the polymerization degree of 5 and 0.08 part of p-toluenesulfonic acid serving as a catalyst are added, after heating reflux reaction for 8 hours under stirring, the acid value of the system is not reduced any more, which indicates that the reaction is finished, the system is cooled to room temperature, washed with 3wt% NaOH solution until the pH of the system is 7.2, and an organic phase is separated. 4.1 mol parts of Glycidyl Methacrylate (GMA) is slowly added into the organic phase, the temperature of a temperature control system is 5-10 ℃, the reaction is carried out for 4 hours, the solvent is removed by reduced pressure distillation, and colorless liquid which is polyfunctional epoxy resin is obtained. The polyfunctional epoxy resin obtained in preparation example 1 has an epoxy value of 0.212 through testing.

Preparation example 2

1 part of pentaerythritol was dissolved in toluene, 4.2 parts of mercapto PEG carboxyl (SH-PEG 10-COOH) with a polymerization degree of 10 and 0.08 part of p-toluenesulfonic acid as a catalyst were added, after heating reflux reaction for 8 hours under stirring, the acid value of the system was no longer reduced, indicating that the reaction had ended, cooled to room temperature, washed with 3wt% NaOH solution to a system pH of 7.4, and the organic phase was separated into layers. 4.1 mol parts of Glycidyl Methacrylate (GMA) is slowly added into the organic phase, the temperature of a temperature control system is 5-10 ℃, the reaction is carried out for 4 hours, the solvent is removed by reduced pressure distillation, and colorless liquid which is polyfunctional epoxy resin is obtained. The polyfunctional epoxy resin obtained in preparation example 2 has an epoxy value of 0.139 after the test.

Example 1

(S1) uniformly mixing 15 parts of dicyclopentadiene type epoxy resin, 8 parts of triglycidyl para-aminophenol and 11 parts of the multifunctional epoxy resin prepared in preparation example 1 to obtain a first mixture;

(S2) 100 parts of spherical silica powder with the D50 of 1.5 mu m is dispersed in an aqueous solution of 80 percent ethanol under the auxiliary condition of ultrasonic, 7 parts of KH-560 and 3 parts of bis- [3- (triethoxysilyl) propyl ] -tetrasulfide are added, and the mixture is reacted for 6 hours at the temperature of 60 ℃ under the stirring condition, filtered, washed by deionized water and dried in vacuum to obtain modified spherical silica powder;

(S3) averagely dividing 55 parts of the modified spherical silicon micro powder prepared in the step (S2) into three parts of the first mixture obtained in the step (S1), stirring for 10min after each addition, and uniformly mixing 3 parts of 2-ethyl-4-methylimidazole and 0.3 part of anti-sedimentation agent BYK 9010; and finally, adding 20 parts of methyl hexahydrophthalic anhydride MH700G, uniformly mixing, and carrying out vacuum defoaming on the system to obtain the modified nanometer material.

Example 2

(S1) uniformly mixing 20 parts of dicyclopentadiene type epoxy resin, 6 parts of triglycidyl para-aminophenol and 8 parts of the multifunctional epoxy resin prepared in preparation example 2 to obtain a first mixture;

(S2) 100 parts of spherical silica powder with the D50 of 1.5 mu m is dispersed in an aqueous solution of 80 percent ethanol under the auxiliary condition of ultrasonic, 9 parts of KH-561 and 1 part of bis- [3- (triethoxysilyl) propyl ] -tetrasulfide are added, and the mixture is reacted for 6 hours at the temperature of 60 ℃ under the stirring condition, filtered, washed by deionized water and dried in vacuum to obtain modified spherical silica powder;

(S3) averagely dividing 45 parts of the modified spherical silicon micro powder prepared in the step (S2) into three parts of the first mixture obtained in the step (S1), stirring for 10min after each addition, and uniformly mixing 5 parts of 2-ethyl-4-methylimidazole and 0.3 part of anti-sedimentation agent BYK 9010; and finally, adding 26 parts of methyl hexahydrophthalic anhydride MH700G, uniformly mixing, and carrying out vacuum defoaming on the system to obtain the modified nanometer material.

Example 3

(S1) uniformly mixing 18 parts of dicyclopentadiene type epoxy resin, 8 parts of triglycidyl para-aminophenol and 10 parts of the multifunctional epoxy resin prepared in preparation example 1 to obtain a first mixture;

(S2) 100 parts of spherical silica powder with the D50 of 1.5 mu m is dispersed in an aqueous solution of 80 percent ethanol under the auxiliary condition of ultrasonic, 8 parts of KH-560 and 2 parts of bis- [3- (triethoxysilyl) propyl ] -tetrasulfide are added, and the mixture is reacted for 6 hours at the temperature of 60 ℃ under the stirring condition, filtered, washed by deionized water and dried in vacuum to obtain modified spherical silica powder;

(S3) averagely dividing 50 parts of the modified spherical silicon micro powder prepared in the step (S2) into three parts of the first mixture obtained in the step (S1), stirring for 10min after each addition, and uniformly mixing 3 parts of 2-ethyl-4-methylimidazole and 0.3 part of anti-sedimentation agent BYK 9010; finally, 22 parts of methyl hexahydrophthalic anhydride MH700G is added, the mixture is uniformly mixed, and the system is subjected to vacuum defoamation, thus obtaining the modified nanometer material.

Example 4

The other conditions were the same as in example 1 except that KH-56 was used in an amount of 5 parts and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide was used in an amount of 5 parts in step (S2).

Example 5

The other conditions were the same as in example 1 except that in step (S1), the amount of the polyfunctional epoxy resin produced in preparation example 1 was 14 parts.

Example 6

The other conditions were the same as in example 1 except that in step (S1), 6 parts of the polyfunctional epoxy resin was used in the amount of 6 parts of the polyfunctional epoxy resin produced in preparation example 1.

Comparative example 1

Other conditions and operations were the same as in example 1 except that KH-560 was used in an amount of 10 parts in step (S2), and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide was not added.

Comparative example 2

Other conditions and operations were the same as in example 1 except that step (S2) was omitted, i.e., the spherical fine silica powder was not modified.

Application example

The performance of the underfill according to the present invention was tested as follows, and the results are shown in Table 1 below:

coefficient of Thermal Expansion (CTE): the test was performed with reference to ASTM E83 using a thermal expansiometer. Wherein CTE1 represents the coefficient of thermal expansion below Tg and CTE2 represents the coefficient of thermal expansion above Tg in ppm/K.

Viscosity of the mixture: the viscosity of the samples was measured at 25℃in accordance with HG/T3660-1999 using a Bowler's laminar viscometer at 10 rpm.

Fluidity of the product:40 μm spacing, the time taken for the actual glue to flow 25mm at a temperature of 80 ℃ in units of: s.

Chip shear thrust (Dieshar): the silicon chip with the thickness of 40 mu m is dipped with glue with the thickness of 2mm multiplied by 2mm and stuck on a PCB substrate for curing, and the silicon chip is tested on a pusher machine at the temperature of 25 ℃.

Double 85 test: and (3) sticking glue with the thickness of 40 mu m on a silicon chip with the thickness of 2mm multiplied by 2mm on a PCB substrate for curing, placing the cured glue for 1000 hours under the double-85 test condition (85 ℃ and 85 RH%), and testing the shearing thrust (Die shear) of the chip under the 25 ℃.

Cold and hot impact test: a silicon chip with the thickness of 40 mu m is dipped with glue with the thickness of 2mm multiplied by 2mm and stuck on a PCB substrate for solidification, after solidification, the silicon chip is subjected to cold and hot impact test, is placed at the temperature of minus 40 ℃ for 2 hours, is placed at the temperature of 120 ℃ for 2 hours, and is cycled for 500 times, and then the shearing of the chip is tested at the temperature of 25 DEG CThrust (Die shear).

TABLE 1 underfill Performance test

As can be seen from the data in Table 1, the underfill composition of the present invention has excellent overall properties, high flowability, low thermal expansion coefficient, high bonding strength to the PCB substrate, excellent aging resistance, high temperature and high humidity resistance, and high bonding strength after cold and hot impact test. The electronic component in the intelligent automobile can be satisfied with the possibly serious environment of the manager, and the reliability and the stability of the auxiliary electronic system of the intelligent automobile are improved.

Claims (12)

1. The underfill adhesive suitable for the intelligent automobile is characterized by comprising the following raw materials in parts by mass: 15-20 parts of dicyclopentadiene type epoxy resin, 6-8 parts of triglycidyl para-aminophenol, 8-11 parts of polyfunctional epoxy resin, 45-55 parts of modified spherical silica micropowder, 20-26 parts of anhydride type epoxy curing agent and 3-5 parts of curing accelerator; the multi-functionality epoxy resin is prepared by esterification reaction of pentaerythritol and/or dipentaerythritol thereof and sulfhydryl polyethylene glycol carboxyl, and then click reaction of sulfhydryl-alkenyl with alkenyl-containing glycidyl ether; the modified spherical silica micropowder is prepared by a preparation method comprising the following steps: dispersing spherical silicon powder in a solvent, adding an epoxy silane coupling agent and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide, reacting for 5-10h under the stirring condition of 60-80 ℃, carrying out suction filtration, washing and drying to obtain modified spherical silicon micro powder; the solvent is at least one of water, ethanol and isopropanol; the mass ratio of the silicon powder, the epoxy silane coupling agent and the bis- [3- (triethoxysilane) propyl ] -tetrasulfide is 100:6-9:1-3; the D50 of the spherical silicon micropowder is 1-10 mu m.

2. The underfill according to claim 1, wherein the solvent is 60-80vol% aqueous ethanol.

3. The underfill of claim 1, wherein the epoxy silane coupling agent is selected from at least one of (3-glycidoxypropyl trimethoxysilane, 3- (2, 3-glycidoxypropyl) propyltriethoxysilane, 3- (2, 3-glycidoxypropyl) propylmethyldimethoxysilane.

4. The underfill according to claim 1, wherein the multifunctional epoxy resin is prepared by esterification of pentaerythritol and/or dipentaerythritol with thiol-PEG carboxyl (SH-PEG-COOH) and then click reaction of thiol-alkenyl with alkenyl-containing glycidyl ether; the number of the repeated units of PEG in the sulfhydryl PEG carboxyl is 5-10; the pentaerythritol derivative is selected from dipentaerythritol; the alkenyl-containing glycidyl ether is at least one selected from glycidyl methacrylate and allyl glycidyl ether.

5. Underfill according to claim 1, wherein pentaerythritol and/or dipentaerythritol are used in amounts satisfying the following relation with the mercapto-PEG carboxyl groups: the molar ratio of hydroxyl (-OH) in pentaerythritol and/or dipentaerythritol to carboxyl (-COOH) in the carboxyl group of sulfhydryl PEG is 1:1-1.2; the mol ratio of the sulfhydryl PEG carboxyl to the alkenyl-containing glycidyl ether is 1:1-1.05.

6. Underfill according to claim 5, wherein the molar ratio of hydroxyl (-OH) in pentaerythritol and/or dipentaerythritol to carboxyl (-COOH) in mercapto-PEG carboxyl is 1:1.05-1.1.

7. The underfill of claim 1, wherein the anhydride based epoxy hardener is selected from at least one of methyl hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, phthalic anhydride, glutaric anhydride.

8. The underfill according to claim 1, wherein the curing accelerator is selected from amine accelerators and/or imidazole accelerators, the amine accelerators being selected from at least one of N, N-dimethylaniline, diethylamine propylamine; the imidazole accelerator is at least one selected from 2-ethyl-4-methylimidazole, 2-butylimidazole, 2-phenyl-4-methylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole.

9. The underfill according to claim 1, wherein the spherical silica fume has a D50 of 1-3 μm.

10. The underfill of claim 1, further comprising 0.3-0.5 parts of an anti-settling agent, 0.5-1 parts of color paste, 0.5-1 parts of a leveling agent, 0.2-0.5 parts of a toughening agent, and 0.05-0.2 parts of an antifoaming agent.

11. The underfill according to claim 10, wherein the anti-settling agent is at least one of BYK9010, BYK-995, BYK-306, BYK-2008; the toughening agent is at least one of dibutyl phthalate and dioctyl phthalate; the defoamer is at least one selected from BYK-320, BYK-322 and BYK-323.

12. The method of preparing an underfill according to any one of claims 1 to 11, comprising the steps of:

(S1) uniformly mixing dicyclopentadiene type epoxy resin, triglycidyl para-aminophenol (AFG-90) and polyfunctional epoxy resin to obtain a first mixture;

(S2) dispersing spherical silicon micropowder in a solvent to obtain dispersion, adding an epoxy silane coupling agent and bis- [3- (triethoxysilyl) propyl ] -tetrasulfide, reacting for 10 hours under the stirring condition of 60-80 ℃, filtering, washing and drying to obtain modified spherical silicon micropowder;

(S3) adding the modified spherical silica powder and the curing accelerator into the first mixture, and uniformly mixing; and finally, adding an anhydride epoxy curing agent, uniformly mixing, and carrying out vacuum defoamation on the system to obtain the epoxy resin.