Electrophoresis slurry as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of electronic elements, and discloses an electrophoretic paste and a preparation method and application thereof. The electrophoretic slurry is prepared from the following components in parts by weight: 22 to 32 parts of modified epoxy resin, 3 to 7 parts of cationic emulsifier, 0.1 to 0.3 part of silane coupling agent, 10 to 16 parts of benzoxazine crosslinking agent, 50 to 65 parts of solvent, 10 to 20 parts of pigment and 3 to 5 parts of inorganic filler, the modified epoxy resin is a copolyester compound with an epoxy resin group at a terminal group. The electrophoresis slurry obtained by compounding the modified epoxy resin, the cationic emulsifier, the silane coupling agent, the benzoxazine cross-linking agent, the solvent, the pigment and the inorganic filler can be used in an electrophoresis protection layer of the chip resistor, so that the prepared chip resistor still has excellent stability under extreme conditions; the influence of extreme environments (temperature, humidity, overload current and the like) on the performance of the resistor is remarkably reduced, and the stable operation of the resistor in a complex environment can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic components, and in particular to an electrophoretic slurry, a preparation method thereof, and an application thereof. Background Art

[0002] Chip resistors are electronic components that can be directly mounted on the surface of a circuit board. They are widely used in electronic devices, and their reliability directly affects the stability and service life of the electronic equipment. During the manufacturing process, chip resistors need to go through electroplating, cleaning, packaging and other process links. The highly corrosive components of the electroplating solution (acidic or alkaline plating solution) can easily penetrate into the interior of the resistor through defects in the protective layer, react chemically with the metal electrodes, and thus cause corrosion of the metal electrodes or degradation of the resistor film layer. At the same time, in a humid environment or under temperature cycling conditions, water vapor penetration will penetrate into the interior of the resistor through defects in the protective layer or tiny gaps in the packaging material, causing problems such as oxidation and ion migration inside the resistor, further exacerbating resistance value drift and even circuit failure.

[0003] Conventional electrophoretic protection technology achieves insulation and protection by forming an organic protective layer (such as epoxy resin, acrylic resin, etc.) on the surface of chip resistors. However, it has the following significant limitations in practical applications: (1) Insufficient resistance to electroplating solution penetration: The existing chip resistor protective layer has a low cross-linking density or a high micro-porosity, which makes it difficult to completely block the Cl in the electroplating solution. - 、SO4 2- The diffusion of plasma, especially when immersed in the plating solution for a long time or under high-pressure process conditions, can easily cause the protective layer to swell or peel off at the interface, resulting in protection failure. (2) Weak resistance to moisture and heat: The glass transition temperature (Tg) of conventional resin systems is low. In high temperature and high humidity environments, the movement of polymer chains intensifies, the water absorption rate of the protective layer increases, forming water molecule penetration channels, and accelerating the electrochemical corrosion process. (3) Poor matching with the substrate: The substrates of chip resistors are mostly ceramics or metal alloys. The existing protective layer is prone to microcracks under thermal stress due to insufficient interface bonding or mismatched thermal expansion coefficients, further reducing the barrier effect. Therefore, the development of a new electrophoretic protection system with high barrier properties, strong adhesion and adaptability to extreme environments has become a key technical bottleneck for improving the reliability of chip resistors. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an electrophoretic slurry and a preparation method and application thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides an electrophoretic slurry comprising the following components in parts by weight: 22-32 parts of a modified epoxy resin, 3-7 parts of a cationic emulsifier, 0.1-0.3 parts of a silane coupling agent, 10-16 parts of a benzoxazine crosslinker, 50-65 parts of a solvent, 10-20 parts of a colorant, and 3-5 parts of an inorganic filler; the modified epoxy resin is a copolyester compound having an epoxy resin group at its terminal end.

[0007] The electrophoretic slurry obtained by compounding a modified epoxy resin, a cationic emulsifier, a silane coupling agent, a benzoxazine crosslinker, a solvent, a colorant, and an inorganic filler can be used in the electrophoretic protective layer of a chip resistor. The prepared chip resistor still has excellent stability under extreme conditions, significantly reducing the impact of extreme environments (temperature, humidity, overload current, etc.) on the resistor performance, and can ensure the stable operation of the resistor in complex environments. Among them, the modified epoxy resin is a copolyester compound with epoxy resin groups at the end groups, the main chain is a copolyester skeleton formed by the condensation reaction of a diol and a dibasic acid (unsaturated dibasic acid), and the two end groups are epoxy resin groups introduced by chemical modification. Its unique structure and molecular design enable the modified epoxy resin, as a key component of the chip resistor electrophoretic protective layer material, to cooperate with other components to significantly improve the stability and reliability of the chip resistor in extreme environments.

[0008] As a preferred embodiment of the electrophoretic slurry of the present invention, the mass ratio of the modified epoxy resin to the benzoxazine crosslinker is (1-3):1.

[0009] Preferably, the mass ratio of the modified epoxy resin to the benzoxazine crosslinker is 2:1.

[0010] As a preferred embodiment of the electrophoretic slurry of the present invention, the electrophoretic slurry includes the following components in parts by weight: 26 parts of modified epoxy resin, 5 parts of cationic emulsifier, 0.2 parts of silane coupling agent, 13 parts of benzoxazine crosslinker, 59 parts of solvent, 15 parts of colorant, and 4 parts of inorganic filler.

[0011] As a preferred embodiment of the electrophoretic slurry of the present invention, the preparation method of the modified epoxy resin comprises the following steps:

[0012] S1, taking a diol, a dibasic acid and a titanium catalyst and reacting them to obtain a copolyester compound; the dibasic acid includes an unsaturated dibasic acid;

[0013] S12, taking the copolyester compound, adding epoxy resin and a catalyst, reacting to obtain the modified epoxy resin.

[0014] The present invention involves a condensation reaction between a diol (1 mol) and a dibasic acid (excess 1.1 mol) under the action of a titanium catalyst to form a linear copolyester chain of the dibasic acid. Subsequently, under the action of the catalyst, the dibasic acid undergoes a ring-opening esterification addition reaction with the epoxy group of the epoxy resin to obtain a modified epoxy resin.

[0015] Preferably, the acid value of the copolyester compound is 32 mgKOH / g-38 mgKOH / g.

[0016] Preferably, the epoxy equivalent of the modified epoxy resin is 200 g / eq-558 g / eq.

[0017] Preferably, the step S1 includes at least any one of the following (1)-(6):

[0018] (1) The molar ratio of the diol to the dibasic acid is 1:(0.8-2);

[0019] (2) The diol is 1,4-butanediol;

[0020] (3) The unsaturated dibasic acid is a dimer acid and / or a trimer acid;

[0021] (4) The dibasic acid further comprises at least one of glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, pimelic acid and dodecanedioic acid;

[0022] (5) The mass of the titanium catalyst is 0.08% to 1.5% of the total mass of the diol and the dibasic acid;

[0023] (6) The reaction temperature is 110°C-120°C and the reaction time is 24h-36h.

[0024] Preferably, the step S2 includes at least any one of the following (I)-(V):

[0025] (I) the mass ratio of the copolyester compound to the epoxy resin is 1:(2-5);

[0026] (II) the epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin;

[0027] (III) the mass of the catalyst is 0.5% to 1% of the mass of the copolyester compound;

[0028] (IV) the catalyst is triphenylphosphine;

[0029] (V) The reaction temperature is 110°C-130°C, and the reaction time is 2h-5h.

[0030] As a preferred embodiment of the electrophoretic slurry of the present invention, the cationic emulsifier is polyethyleneimine.

[0031] As a preferred embodiment of the electrophoretic slurry of the present invention, the silane coupling agent is an epoxy silane coupling agent.

[0032] As a preferred embodiment of the electrophoretic slurry of the present invention, the colorant is carbon black.

[0033] As a preferred embodiment of the electrophoretic slurry of the present invention, the inorganic filler is fumed silica.

[0034] As a preferred embodiment of the electrophoretic slurry of the present invention, the solvent is dimethyl glycol monobutyl ether.

[0035] In a second aspect, the present invention provides a method for preparing the electrophoretic slurry, comprising the following steps:

[0036] S1, mixing the modified epoxy resin and the benzoxazine crosslinker, adding the cationic emulsifier, stirring and dispersing, emulsifying and homogenizing to obtain a mixture A;

[0037] S2, mixing the mixture A and the silane coupling agent, and stirring to obtain a mixture B;

[0038] S3, mixing the mixture B with the colorant and the inorganic filler, and grinding them to obtain a mixture C;

[0039] S4, mixing the mixture C and the solvent.

[0040] As a preferred embodiment of the method for preparing the electrophoretic slurry of the present invention, in step S1, the temperature of the emulsification and homogenization is 90° C.-110° C., and the time is 0.5 h-3 h.

[0041] As a preferred embodiment of the method for preparing the electrophoretic slurry of the present invention, in step S1, the rotation speed of the emulsification and homogenization is 10000 rpm to 50000 rpm.

[0042] As a preferred embodiment of the method for preparing the electrophoretic slurry of the present invention, the solid content of the mixture A is 35 wt % to 50 wt %.

[0043] In a third aspect, the present invention provides use of the electrophoretic slurry in preparing electronic components.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows: First, the electrophoretic slurry obtained by compounding modified epoxy resin, cationic emulsifier, silane coupling agent, benzoxazine crosslinker, solvent, colorant and inorganic filler can be used in the electrophoretic protective layer of chip resistors, so that the prepared chip resistor still has excellent stability under extreme conditions, significantly reducing the influence of extreme environment (temperature, humidity, overload current, etc.) on the resistor performance, and can ensure the stable operation of the resistor in a complex environment. Secondly, the electrophoretic protective layer prepared by the electrophoretic slurry of the present invention has a high glass transition temperature (Tg), so that the electrophoretic protective layer of the chip resistor has excellent dimensional stability and resistance to softening and deformation under high temperature conditions, and can avoid microcracks caused by thermal expansion mismatch. At the same time, the electrophoretic protective layer prepared by the electrophoretic slurry of the present invention performs well in harsh tests such as solvent resistance, temperature cycling and short-term overload, and fully covers the protection needs of resistors in complex application scenarios. In addition, the preparation method of the electrophoretic slurry of the present invention has mild reaction conditions, simple operating steps, and is easy to scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 1 is a reaction flow chart of the modified epoxy resin of the present invention. DETAILED DESCRIPTION

[0046] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] The following is an elaboration with reference to specific embodiments to illustrate the practical effects of the present invention.

[0048] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, equipment, etc. used are all available from commercial sources unless otherwise specified.

[0049] The raw materials used in the following examples and comparative examples are described below, but are not limited to these materials:

[0050] Table 1 Manufacturer model information of raw materials of the present invention

[0051]

[0052] Example 1:

[0053] (1) Preparation of modified epoxy resin (see the specific reaction process Figure 1 )

[0054] (i) Condensation Reaction: In a four-port split-flow stirred reactor, 1 mol of 1,4-butanediol, 0.6 mol of low-surface-energy dimer acid, 0.5 mol of low-surface-energy trimer acid, and a Ti catalyst (the mass of the Ti catalyst being 0.1% of the total mass of the 1,4-butanediol, low-surface-energy dimer acid, and low-surface-energy trimer acid) were added. The temperature was raised to 115° C. and the condensation reaction was carried out for 24 hours. Water was produced as a by-product. The product was collected and analyzed, and the acid value of the obtained condensation product was 35.2 mgKOH / g, which was within the theoretical value of 32 mgKOH / g to 38 mgKOH / g, thereby obtaining a copolyester compound.

[0055] (ii) Addition reaction: 200 g of the copolyester compound prepared in step (a) was added with 798 g of bisphenol F epoxy resin (epoxy equivalent weight: 186 g / eq) and 2 g of triphenylphosphine catalyst. The mixture was heated to 120° C. and stirred at 300 rpm with a large blade for 3 hours. A sample was taken for acid value measurement. The reaction was terminated when the acid value was less than 0.1 mgKOH / g. The epoxy equivalent weight of the resulting modified epoxy resin was 251.5 g / eq.

[0056] (2) Preparation of electrophoretic slurry

[0057] The electrophoretic slurry of this embodiment includes: 520g modified epoxy resin, 100g polyethyleneimine, 4g epoxy silane coupling agent, 1180g dimethyl glycol monobutyl ether, 300g carbon black, 80g fumed silica, and 260g water-based benzoxazine (SBZ) crosslinking agent.

[0058] (i) A modified epoxy resin and a water-based benzoxazine (SBZ) crosslinker were added to a reflux reaction apparatus, and polyethyleneimine was added after stirring. The mixture was emulsified and homogenized at 100° C. for 1 hour to neutralize and ionize the resin. The mixture was dispersed at 20,000 rpm using an emulsifier homogenizer for 90 minutes to obtain an emulsion with a solid content of 40 wt%.

[0059] (ii) The above emulsion and epoxy silane coupling agent were mixed and stirred at a temperature of 40° C. and a pressure of normal pressure. Carbon black and fumed silica were then added and ground in a grinder. The ground product was mixed with dimethyl glycol monobutyl ether to obtain an electrophoretic slurry.

[0060] Example 2:

[0061] The only difference between this embodiment and Example 1 is that in step (2), the electrophoretic slurry of this embodiment includes: 580g modified epoxy resin, 100g polyethyleneimine, 4g epoxy silane coupling agent, 1180g dimethyl glycol monobutyl ether, 300g carbon black, 80g fumed silica, and 200g water-based benzoxazine (SBZ) crosslinking agent.

[0062] Example 3:

[0063] The only difference between this embodiment and Example 1 is that in step (2), the electrophoretic slurry of this embodiment includes: 600g modified epoxy resin, 100g polyethyleneimine, 4g epoxy silane coupling agent, 1180g dimethyl glycol monobutyl ether, 300g carbon black, 80g fumed silica, and 130g water-based benzoxazine (SBZ) crosslinking agent.

[0064] Example 4:

[0065] The only difference between this embodiment and embodiment 1 is that in step (i) of step (1), 0.6 mol of low surface energy dimer acid and 0.5 mol of low surface energy trimer acid are replaced by 0.2 mol of low surface energy dimer acid, 0.2 mol of low surface energy trimer acid and 0.7 mol of adipic acid.

[0066] Example 5:

[0067] The only difference between this embodiment and embodiment 1 is that in step (i) of step (1), 0.6 mol of low surface energy dimer acid and 0.5 mol of low surface energy trimer acid are replaced by 0.2 mol of low surface energy dimer acid and 0.9 mol of adipic acid.

[0068] Example 6:

[0069] The only difference between this embodiment and embodiment 1 is that in step (i) of step (1), 0.6 mol of low surface energy dimer acid and 0.5 mol of low surface energy trimer acid are replaced by 0.2 mol of low surface energy dimer acid and 0.9 mol of dodecanedioic acid.

[0070] Example 7:

[0071] The only difference between this comparative example and Example 1 is that in step (i) of step (1), 0.6 mol of low surface energy dimer acid and 0.5 mol of low surface energy trimer acid are replaced by 0.4 mol of low surface energy trimer acid and 0.7 mol of adipic acid.

[0072] Example 8:

[0073] The only difference between this embodiment and embodiment 1 is that the mass of the copolyester compound in step (ii) of step (1) is 250 g, and the mass of the bisphenol F epoxy resin is 748 g.

[0074] Example 9:

[0075] The only difference between this embodiment and embodiment 1 is that in step (ii) of step (1), the mass of the copolyester compound is 300 g, and the mass of the bisphenol F epoxy resin is 698 g.

[0076] Example 10:

[0077] The only difference between this embodiment and embodiment 1 is that in step (ii) of step (1), the mass of bisphenol F epoxy resin is 400 g.

[0078] Example 11:

[0079] The only difference between this embodiment and embodiment 1 is that in step (ii) of step (1), the mass of bisphenol F epoxy resin is 1000 g.

[0080] Comparative Example 1:

[0081] The only difference between this comparative example and Example 1 is that in step (i) of step (1), 0.6 mol of low surface energy dimer acid and 0.5 mol of low surface energy trimer acid are replaced by 1.1 mol of adipic acid.

[0082] Comparative Example 2:

[0083] The only difference between this comparative example and Example 1 is that in step (i) of step (1), 0.6 mol of low surface energy dimer acid and 0.5 mol of low surface energy trimer acid are replaced by 1.1 mol of dodecanedioic acid.

[0084] Comparative Example 3:

[0085] The only difference between this comparative example and Example 1 is that the mass of the copolyester compound in step (ii) of step (1) is 50 g, and the mass of the bisphenol F epoxy resin is 948 g.

[0086] Comparative Example 4:

[0087] The only difference between this comparative example and Example 1 is that in step (ii) of step (1), the mass of the copolyester compound is 100 g, and the mass of the bisphenol F epoxy resin is 898 g.

[0088] Comparative Example 5:

[0089] The only difference between this comparative example and Example 1 is that the mass of the copolyester compound in step (ii) of step (1) is 400 g, and the mass of the bisphenol F epoxy resin is 598 g.

[0090] Comparative Example 6:

[0091] The only difference between this comparative example and Example 1 is that the mass of the copolyester compound in step (ii) of step (1) is 500 g, and the mass of the bisphenol F epoxy resin is 498 g.

[0092] Comparative Example 7:

[0093] The only difference between this comparative example and Example 1 is that in step (ii) of step (1), the mass of bisphenol F epoxy resin is 100 g.

[0094] Comparative Example 8:

[0095] The only difference between this comparative example and Example 1 is that in step (ii) of step (1), the mass of bisphenol F epoxy resin is 1600 g.

[0096] Comparative Example 9:

[0097] The only difference between this comparative example and Example 1 is that the modified epoxy resin in step (2) is replaced by an equal amount of bisphenol F epoxy resin.

[0098] Comparative Example 10:

[0099] This comparative example is a commercially available electrophoretic slurry (purchased from: Guangdong Dewei Paint, model: DW-6000).

[0100] Test Example 1:

[0101] The electrophoretic slurry in this embodiment is suitable for manufacturing the electrophoretic protective layer of chip resistors, and is particularly suitable for small-sized chip resistors of 0201, 01005, and 008004 sizes.

[0102] Take the 0201 model chip resistor semi-finished product, and coat the electrophoretic slurry of the above embodiment and comparative example on the surface of the semi-finished product by electrophoretic plating, post-curing, primary segmentation, sputtering side conductor, secondary segmentation, deposition, and obtain the finished chip resistor for performance testing.

[0103] (1) Resistance value stability test

[0104] Test standard: According to IEC60115 test specification

[0105] Test method: After 80 finished chip resistors are steamed at 121°C for 6 hours (simulating extreme heat and humidity aging), the rated current is continuously supplied for 3 hours to determine the resistance change rate (%).

[0106] Judgment standard: Resistance change rate (%)>0.5 is unqualified.

[0107] (2) 100-grid tape test

[0108] Test standard: Evaluate the interfacial bonding strength between the electrophoretic protective layer and the chip resistor substrate according to ASTM D3359 Method B / ISO 2409:2013;

[0109] Test method: Use a 6-blade cutting knife to cut into the electrophoretic protective layer until the substrate is completely exposed, and mark 10×10 1mm 2Grid, stick the tape tightly to the cutting area and tear it off quickly to observe the shedding of the electrophoretic protective layer.

[0110] Judgment criteria: Adhesion grade <5B is unqualified; Adhesion grade 5B, the cutting edge is smooth and there is no falling off; Adhesion grade 4B, the falling off area ≤5%; Adhesion grade 3B, the falling off area 5% to 15%; Adhesion grade 2B, the falling off area 15% to 35%; Adhesion grade 1B, the falling off area 35% to 65%; Adhesion grade 0B, the falling off area >65%.

[0111] (3) Glass transition temperature (Tg) test

[0112] The glass transition temperature (Tg) of the cured electrophoretic protective layer was tested using a scanning calorimeter (DSC). A Tg < 100°C was considered unqualified (insufficient temperature resistance and prone to thermal deformation).

[0113] Table 2 Rapid evaluation test results of test example 1 of the present invention

[0114] Components Resistance change rate (%) Adhesion grade Glass transition temperature (Tg) (℃) Example 1 0.01％-0.08％ 5B 135 Example 2 0.12％-0.15％ 4B 108 Example 3 0.38％-0.96％ 3B 96 Example 4 0.03％-0.16％ 5B 119 Example 5 0.10％-0.32％ 5B 100 Example 6 0.11％-0.30％ 5B 100 Example 7 0.32％-0.42％ 5B 120 Example 8 0.08％-0.12％ 5B 110 Example 9 0.05％-0.08％ 5B 103 Example 10 0.01％-0.05％ 5B 83 Example 11 0.38％-0.78％ 4B 115 Comparative Example 1 0.5％-0.92％ 5B 102 Comparative Example 2 0.42％-0.75％ 5B 95 Comparative Example 3 0.83％-1.22％ 4B 126 Comparative Example 4 0.4％-0.62％ 4B 121 Comparative Example 5 0.02％-0.05％ 5B 92 Comparative Example 6 0.01％-0.02％ 5B 76 Comparative Example 7 6.88-Open Circuit 5B 53 Comparative Example 8 0.88％-1.51％ 4B 141 Comparative Example 9 1.21％-2.11％ 3B 146 Comparative Example 10 0.99％-1.62％ 4B 115

[0115] As can be seen from the results in Table 2, the chip resistors prepared with the electrophoretic slurry of the embodiment of the present invention still have excellent stability after extreme heat and humidity aging, with the minimum resistance change rate between 0.01% and 0.08%. This change rate indicates that the chip resistor can still maintain excellent electrical stability under extreme heat and humidity conditions. The electrophoretic protective layer prepared with the electrophoretic slurry of the embodiment of the present invention has an adhesion grade of up to 5B to the chip resistor substrate, indicating that the electrophoretic protective layer has extremely strong bonding with the chip resistor substrate and is not easy to fall off or peel off. The electrophoretic protective layer prepared with the electrophoretic slurry of the embodiment of the present invention has a glass transition temperature of up to 135°C, which indicates that the electrophoretic protective layer can still maintain its physical and chemical stability at higher temperatures and is not easy to soften or deform.

[0116] Test Example 2:

[0117] This test example conducts reliability tests on chip resistors prepared with the electrophoretic slurries of the embodiment and the comparative example.

[0118] Table 3 Reliability test results of chip resistors prepared by electrophoretic slurry according to the embodiment of the present invention

[0119]

[0120] Table 4 Reliability test results of chip resistors prepared by electrophoretic slurry according to the comparative example of the present invention

[0121]

[0122]

[0123] This test example conducts a series of reliability tests on the chip resistors prepared with the electrophoretic slurry of the embodiment and the comparative example to comprehensively evaluate their performance under different conditions. The test items include temperature coefficient of resistance (TCR), steady-state damp heat performance test, 70°C durability performance test, high temperature storage performance test, solvent resistance performance test, temperature cycle test, short-time overload performance test and half-break ratio test. It can be seen from the results of Table 3 and Table 4 that the good protection of the electrophoretic protective layer prepared by the electrophoretic slurry in the embodiment of the present invention significantly reduces the impact of extreme environments (temperature, humidity, overload current, etc.) on the resistor performance, and can ensure the stable operation of the resistor in a complex environment.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An electrophoretic slurry, characterized in that: The invention comprises the following components in parts by weight: 22-32 parts of modified epoxy resin, 3-7 parts of cationic emulsifier, 0.1-0.3 parts of silane coupling agent, 10-16 parts of benzoxazine crosslinking agent, 50-65 parts of solvent, 10-20 parts of colorant, and 3-5 parts of inorganic filler; the modified epoxy resin is a copolyester compound with an epoxy resin group at the terminal.

2. The electrophoretic slurry according to claim 1, wherein: The preparation method of the modified epoxy resin comprises the following steps: S1, taking a diol, a dibasic acid and a titanium catalyst and reacting them to obtain a copolyester compound; the dibasic acid includes an unsaturated dibasic acid; S2. Take the copolyester compound, add epoxy resin and catalyst, and react to obtain the modified epoxy resin.

3. The electrophoretic slurry according to claim 2, wherein: The step S1 includes at least any one of the following (1)-(6): (1) The molar ratio of the diol to the dibasic acid is 1:(0.8-2); (2) The diol is 1,4-butanediol; (3) The unsaturated dibasic acid is a dimer acid and / or a trimer acid; (4) The dibasic acid further comprises at least one of glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, pimelic acid and dodecanedioic acid; (5) The mass of the titanium catalyst is 0.08% to 1.5% of the total mass of the diol and the dibasic acid; (6) The reaction temperature is 110°C-120°C and the reaction time is 24h-36h.

4. The electrophoretic slurry according to claim 2, wherein: The step S2 includes at least any one of the following (I)-(V): (I) the mass ratio of the copolyester compound to the epoxy resin is 1:(2-5); (II) the epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin; (III) the mass of the catalyst is 0.5% to 1% of the mass of the copolyester compound; (IV) the catalyst is triphenylphosphine; (V) The reaction temperature is 110°C-130°C, and the reaction time is 2h-5h.

5. The electrophoretic slurry according to claim 2, wherein: The acid value of the copolyester compound is 32 mgKOH / g-38 mgKOH / g; and the epoxy equivalent of the modified epoxy resin is 200 g / eq-558 g / eq.

6. The electrophoretic slurry according to claim 1, wherein: The cationic emulsifier is polyethyleneimine; and the silane coupling agent is an epoxy silane coupling agent.

7. The method for preparing the electrophoretic slurry according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) mixing the modified epoxy resin and the benzoxazine crosslinker, adding the cationic emulsifier, stirring, dispersing, emulsifying and homogenizing to obtain a mixture A; (2) mixing the mixture A and the silane coupling agent, and stirring to obtain a mixture B; (3) mixing the mixture B with the colorant and the inorganic filler, and grinding them to obtain a mixture C; (4) Mixing the mixture C and the solvent to obtain the product.

8. The method for preparing the electrophoretic slurry according to claim 7, wherein: In step (1), the temperature of the emulsification and homogenization is 90° C.-110° C.; the time of the emulsification and homogenization is 0.5 h-3 h.

9. The method for preparing the electrophoretic slurry according to claim 7, wherein: The solid content of the mixture A is 35 wt%-50 wt%.

10. Use of the electrophoretic slurry according to any one of claims 1 to 6 in electronic components.

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