Black insulation resistance ink and preparation method thereof

Abstract

The invention belongs to the technical field of electronic materials, and particularly relates to black insulation resistance ink and a preparation method thereof.The black insulation resistance ink comprises bisphenol A epoxy resin, phenoxy resin, o-cresol formaldehyde epoxy resin, a benzoxazine curing agent, a compound solvent, a latent curing agent, black pigment, functional filler, auxiliaries and a conductive inhibitor, the black insulation resistance ink meets 350-mesh screen printing, and adopts a gradient heating curing process. According to the invention, a synergistic curing mechanism of benzoxazine, o-cresol formaldehyde epoxy resin (OCFEN) and latent imidazole is combined, low-temperature pre-curing and high-temperature compact crosslinking are realized through a gradient heating process, and process adaptability and material performance are considered at the same time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic materials, and particularly relates to a black insulating resistance ink based on the synergistic effect of benzoxazine, o-cresol formaldehyde epoxy resin and latent curing agent, and a low-temperature pre-curing and high-temperature deep cross-linking method thereof achieved through a gradient heating curing process. The black insulating resistance ink can be printed on substrates such as synthetic resins, ceramics and metals through silk screen printing. The black insulating resistance ink is suitable for high-frequency PCBs, power modules and third-generation semiconductor packaging. BACKGROUND

[0002] Traditional insulating inks mostly use a single epoxy resin system, which has a high curing temperature (>180℃) and a long curing time, and is prone to cause thermal deformation of the substrate, and has high brittleness and poor moisture resistance after curing. Benzoxazine can be used as a main resin for curing alone or as a curing agent, and has advantages such as low shrinkage and high heat resistance (Tg>200℃), but its curing temperature is still high (160-220℃). O-cresol formaldehyde epoxy resin (OCFEN) can improve the bonding strength as a high-performance curing agent, but the reactivity is insufficient when used alone. Latent imidazole curing agents can be triggered at low temperature through microencapsulation, but have poor long-term storage stability. Traditional insulating inks have low thermal conductivity and high dielectric loss. SUMMARY

[0003] In view of the above deficiencies of the prior art, the present application aims to provide a black insulating resistance ink and a preparation method thereof.

[0004] To achieve the above-mentioned purpose, the technical solution adopted is as follows: One of the purposes of the present application is to provide a black insulating resistance ink, which comprises bisphenol A epoxy resin (ER), phenoxy resin, o-cresol formaldehyde epoxy resin (OCFEN), benzoxazine (BZ) curing agent, compounded solvent, latent curing agent, black pigment, functional filler, additive and conductive inhibitor. The black insulating resistance ink meets the requirements of 350-mesh silk screen printing and adopts a gradient heating curing process.

[0005] Preferably, the bisphenol A epoxy resin (ER) is a solid epoxy resin with a large molecular weight, and more preferably has a weight average molecular weight of 700-1000; the phenoxy resin has a weight average molecular weight of 50000-70000 and is a polycondensation resin of bisphenol A and bisphenol F; the o-cresol formaldehyde epoxy resin is preferably a nitrogen-containing o-cresol formaldehyde epoxy resin, and preferably has a Tg temperature of 80℃-100℃; and the benzoxazine curing agent is preferably a liquid benzoxazine of bisphenol A / aniline type with a double functionality and a Tg temperature of 200℃-300℃. Preferably, the bisphenol A epoxy resin (ER), ortho-cresol formaldehyde epoxy resin (OCFEN), benzoxazine (BZ) need to be dissolved with a complex solvent respectively to prepare a liquid resin with a solute mass concentration (solid mass content) of 70%, and the phenoxy resin is prepared into a liquid resin with a solute mass concentration (solid mass content) of 30%. Preferably, the complex solvent can be two or more of diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, propylene glycol phenyl ether, propylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate. It meets the gradient curing process, and more preferably, propylene glycol phenyl ether and diethylene glycol monoethyl ether are compounded, and the mass ratio of the complex is preferably 1:2.

[0006] The bisphenol A epoxy resin (ER), phenoxy resin, ortho-cresol formaldehyde epoxy resin (OCFEN), and benzoxazine (BZ) curing agent all need to be added in a 70 ℃ complex solvent while stirring, and dissolved to the required concentration.

[0007] Preferably, the latent curing agent is a microcapsule type imidazole curing agent, and more preferably, the particle size is within 3 microns.

[0008] Preferably, the black pigment is Fe3O4, which needs to be treated by insulation modification, and the modified coating layer is nanosilica and polyaniline with a particle size of 80-120 nm.

[0009] Preferably, the functional filler is boron nitride and silicon powder. The silicon powder is preferably fused silicon powder. The particle size of both is preferably 0.5-1 micron.

[0010] Preferably, the auxiliary agent includes a dispersant, a leveling agent, a coupling agent, a sagging prevention agent, and a viscosity reducer.

[0011] Preferably, the dispersant is preferably an acrylate, the leveling agent is preferably an organic silicon, the coupling agent is preferably an epoxy, the sagging prevention agent is preferably a polyurea, and the viscosity reducer is preferably synthetic beeswax.

[0012] Preferably, the conductive inhibitor is a composite of graphene and tungsten carbide, and the mass ratio of the two is preferably 1:1.

[0013] Preferably, the black insulating resist ink contains the following components in terms of mass fraction: 70% bisphenol A epoxy resin (ER) 10-30 black pigment 1-3 30% phenoxy resin 2-15 boron nitride 2-15 70% ortho-cresol formaldehyde epoxy resin (OCFEN) 10-30 silicon powder 20-40 30% benzoxazine (BZ) curing agent 10-30 dispersant 0-5 Complex solvent 5-20 leveling agent 0-2 Latent curing agent 0.1-1 Anti-sag agent 0-2 Viscosity reducer 0-5 Conductivity inhibitor 0-1 Coupling agent 0-2 More preferably, the black insulating resistance ink comprises the following components by mass fraction: 70% bisphenol A epoxy resin (ER) 15-20 black pigment 1-2 30% phenoxy resin 5-10 boron nitride 5-10 70% o-cresol formaldehyde epoxy resin (OCFEN) 15-20 silicon powder 25-35 30% benzoxazine (BZ) curing agent 15-20 dispersant 0.5-2 Compound solvent 5-15 leveling agent 0.2-1 Latent curing agent 0.1-0.5 Anti-sag agent 0-1 Viscosity reducer 0-2 Conductivity inhibitor 0-0.5 Coupling agent 0-1 The second object of the present application is to provide a preparation method of a black insulating resistance ink, comprising the following steps: (1) adding 70% bisphenol A epoxy resin (ER), 30% phenoxy resin, 70% o-cresol formaldehyde epoxy resin (OCFEN), and 30% benzoxazine (BZ) curing agent into a stirred tank according to the formula amount; (2) adding a viscosity reducer and a compound solvent, stirring until the viscosity reducer is dissolved, and the rotation speed is 500 rpm; (3) reducing the rotation speed to 200 rpm, adding a dispersant and a black pigment, and then stirring at a rotation speed of 500 rpm for 30 minutes; (4) reducing the rotation speed to 200 rpm, adding boron nitride and silicon powder, and then stirring at a rotation speed of 500 rpm for 30 minutes; (5) adding a coupling agent, a leveling agent, an anti-sag agent, and a conductivity inhibitor and stirring for 10 minutes; (6) reducing the rotation speed to 200 rpm, adding a latent curing agent, and then stirring at a low speed for 10 minutes, with the stirring temperature controlled at 30-40°C; (7) discharging under air pressure, and then grinding on a hydraulic three-roll mill for five times to about 1 micron; (8) vacuum degassing; and (9) gradient heating and curing.

[0014] The gradient heating and curing comprises a pre-curing stage of 25-80°C, a main curing stage of 80-180°C, and a post-curing stage of 180-200°C. The gradient curing time distribution and the temperature rising rate are calculated as follows:

[0015] Compared with the prior art, the present application has the following beneficial effects: The present application combines the synergistic curing mechanism of benzoxazine, OCFEN, and latent imidazole, realizes low-temperature pre-curing and high-temperature dense crosslinking through a gradient temperature rising process, and simultaneously considers process adaptability and material performance.

[0016] The rigid benzene ring structure of OCFEN enhances the interface adhesion, the benzoxazine provides high crosslinking density, the latent imidazole realizes process window widening, and the gradient curing balances production efficiency and material performance. Add boron nitride material, the thermal conductivity is improved to 3.8 W / mK, while the dielectric loss (≤0.001@40GHz) is maintained, the 40GHz dielectric loss is reduced by 72% compared with traditional black ink, supporting terahertz band application. The synergistic optimization of high temperature stability (Tg≥280℃) and optical shielding property (L* value ≤15). Fe3O4@SiO2@PANI core-shell structure realizes near-infrared reflectivity >85% (800-2500nm) and dielectric loss suppression (Δtanδ<0.0005). WC@graphene constructs a three-dimensional conductive suppression network (arc resistance >180s, ASTM D495).

[0017] Process innovation: screen printing line width precision reaches ±1μm (350 mesh screen), suitable for Mini LED packaging.

[0018] Gradient curing adaptability: prolong the solvent release path in the pre-curing stage, avoid stress concentration caused by high filler.

[0019] Printing suitability: viscosity gradient matches 350 mesh screen, realizes ≤50μm line width precision; Electrical performance: volume resistivity ≥1×10¹ 5 Ω·cm (ASTM D257); Process controllability: latent imidazole makes ink storage period ≥6 months (40℃), curing efficiency is improved by 30%. DETAILED DESCRIPTION

[0020] The present application is described below in conjunction with examples, which are only used to explain the present application, and are not used to limit the scope of the present application.

[0021] The formula composition (mass fraction) of the black insulating resistance ink of the present application is as follows: 70% bisphenol A epoxy resin (ER) 15-20 black pigment 1-2 30% phenoxy resin 5-10 boron nitride 5-10 70% o-cresol formaldehyde epoxy resin (OCFEN) 15-20 silicon powder 25-35 30% benzoxazine (BZ) curing agent 15-20 dispersing agent 0.5-2 Compound solvent 5-15 leveling agent 0.2-1 Latent curing agent 0.1-0.5 anti-sagging agent 0-1 Viscosity reducer 0-2 conductive inhibitor 0-0.5 Coupling agent 0-1.

[0022] The specific embodiment formula is as follows:

[0023] The main raw material manufacturers are as follows: EA 907-South Asia; phenoxy resin YP50-Guduo Chemical; OCFEN 704-Saintquan Stock; BZ 8078-Chengdu Keyi High Polymer; latent curing agent PN50-Japan Ajinomoto; viscosity reducer L210-Henan Xinyang Wax Factory; coupling agent 6040-Japan Shin Etsu; black pigment T-4-Yantai Blythe; boron nitride N50-Ningbo Bors; silicon powder 2500-Lian Sheng Stock; dispersant 9076-Bik Chemicals, leveling agent 354-Bik Chemicals, anti-sagging agent 410-Bik Chemicals; conductive inhibitor DYJ-Yantai Blythe; The specific embodiment steps (see the above table for the embodiment ratio): (1) Prepare 1 kg of the required concentration of bisphenol A epoxy resin (ER), phenoxy resin, o-cresol formaldehyde epoxy resin (OCFEN), and benzoxazine (BZ) curing agent solution, all of which need to be added in 70 ℃ complex solvent while stirring, and dissolved to the respective concentration.

[0024] (2) Add 70% bisphenol A epoxy resin (ER), 30% phenoxy resin, 70% o-cresol formaldehyde epoxy resin (OCFEN), and 30% benzoxazine (BZ) curing agent according to the formula amount into the stirring kettle.

[0025] (3) Add viscosity reducer and complex solvent, stir until the viscosity reducer is dissolved, and the rotation speed is 500 rpm.

[0026] (4) The rotation speed is reduced to 200 rpm, the dispersant, black pigment is added, and then the rotation speed is 500 rpm and stirred for 30 minutes.

[0027] (5) The rotation speed is reduced to 200 rpm, boron nitride and silicon powder are added, and then the rotation speed is 500 rpm and stirred for 30 minutes.

[0028] (6) Add coupling agent, leveling agent, anti-sagging agent, and conductive inhibitor and stir for 10 minutes; (7) The rotation speed is reduced to 200 rpm, the latent curing agent is added, and then low-speed stirring is carried out for 10 minutes, and the stirring temperature is controlled at 30-40 ℃.

[0029] (8) Air pressure discharge, and then grinding on a hydraulic three-roll mill for five times to about 1 micron and discharging.

[0030] (9) Vacuum degassing.

[0031] (10) The ink prepared in the above example was printed on a ceramic substrate with a thickness of 1 mm by screen printing. Gradient heating and curing in an oven, and the gradient curing time distribution and temperature rise rate were calculated as follows:

[0032] In the examples, the effects of the raw materials boron nitride, black pigment, viscosity reducer and latent curing agent involved in the comparative innovation on the performance and process were mainly verified.

[0033] 1. Performance verification data comparison

[0034] 2. Process compatibility test (1) Printability: Under a 300-mesh screen, the printing thickness was 25±3 μm, and the edge definition reached ±5 μm.

[0035] (2) Storage stability: The viscosity change rate was less than or equal to 8% at 40°C for 30 days, and the microcapsule curing agent did not break prematurely (DSC detection trigger temperature maintained at 120°C).

[0036] The present application is not limited to the raw materials listed in the claims, and as long as the gradient heating and curing process and performance requirements are met, the raw materials used in the epoxy resin system are within the scope of the patent protection.

[0037] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A black insulating resistance ink, characterized in that, It contains bisphenol A epoxy resin, phenoxy resin, o-cresol epoxy resin, benzoxazine curing agent, compound solvent, latent curing agent, black pigment, functional filler, additives, and conductivity inhibitor. The black insulating resistance ink is suitable for 350 mesh screen printing and adopts a gradient heating curing process.

2. The black insulating resistance ink according to claim 1, characterized in that, The bisphenol A epoxy resin is a high molecular weight solid epoxy resin with a weight average molecular weight between 700 and 1000; the phenoxy resin has a weight average molecular weight between 50,000 and 70,000 and is a condensation resin of bisphenol A and bisphenol F; the o-cresol epoxy resin is a nitrogen-containing o-cresol epoxy resin with a Tg temperature between 80°C and 100°C; the benzoxazine curing agent is a bifunctional bisphenol A / aniline type liquid benzoxazine with a Tg temperature between 200°C and 300°C.

3. The black insulating resistance ink according to claim 1, characterized in that, The bisphenol A epoxy resin, o-cresol epoxy resin, and benzoxazine are all prepared as liquid resins with a solid content of 70% by mass, and the phenoxy resin is prepared as a liquid resin with a solid content of 30% by mass. The compounding solvent is at least two of the following: diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, propylene glycol phenyl ether, propylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, and diethylene glycol butyl ether acetate.

4. The black insulating resistance ink according to claim 1, characterized in that, The latent curing agent is a microencapsulated imidazole curing agent with a particle size of less than 3 micrometers; the black pigment is Fe3O4, which needs to undergo insulation modification treatment, and its modified coating layer is nano-silica and polyaniline with a particle size of 80-120nm; the functional filler is boron nitride and silicon micro powder, and the silicon micro powder is fused silicon micro powder, both with a particle size of 0.5-1 micrometer.

5. The black insulating resistance ink according to claim 1, characterized in that, The additives include dispersants, leveling agents, coupling agents, anti-sagging agents, and viscosity reducers.

6. The black insulating resistance ink according to claim 5, characterized in that, The dispersant is an acrylate, the leveling agent is an organosilicon, the coupling agent is an epoxy, the anti-sagging agent is a polyurea, and the tack reducer is synthetic beeswax; the conductive inhibitor is a composite of graphene and tungsten carbide in a mass ratio of 1:

1.

7. The black insulating resistance ink according to claim 1, characterized in that, Based on parts by weight, it contains the following components: 70% Bisphenol A epoxy resin 10-30 black pigment 1-3 30% phenoxy resin 2-15 boron nitride 2-15 70% o-cresol formaldehyde epoxy resin 10-30% silica powder 20-40% 30% benzoxazine curing agent 10-30 dispersant 0-5 Compound solvent 5-20, leveling agent 0-2 Latent curing agent 0.1-1, anti-sagging agent 0-2 Tack reducer 0-5% conductivity inhibitor 0-1% Coupling agent 0-2.

8. The black insulating resistance ink according to claim 1, characterized in that, Based on parts by weight, it contains the following components: 70% Bisphenol A epoxy resin 15-20 black pigment 1-2 30% phenoxy resin 5-10 boron nitride 5-10 70% o-cresol formaldehyde epoxy resin 15-20% silica powder 25-35% 30% benzoxazine curing agent 15-20, dispersant 0.5-2 Compound solvent 5-15, leveling agent 0.2-1 Latent curing agent 0.1-0.5g, anti-sagging agent 0-1g Tack reducer 0-2%, conductivity inhibitor 0-0.5%. Coupling agent 0-1.

9. A method for preparing a black insulating resistance ink as described in any one of claims 1 to 8, characterized in that, The process includes the following steps: (1) Add 70% bisphenol A epoxy resin, 30% phenoxy resin, 70% o-cresol epoxy resin, and 30% benzoxazine curing agent to a mixing tank according to the formula amount; (2) Add a viscosity reducer and a compound solvent, and stir until the viscosity reducer is dissolved at a speed of 500 rpm; (3) Reduce the speed to 200 rpm, add a dispersant and a black pigment, and then stir at a speed of 500 rpm for 30 minutes; (4) Reduce the speed to 200 rpm, add boron nitride and silica powder, and then stir at a speed of 500 rpm for 30 minutes; (5) Add a coupling agent, a leveling agent, an anti-sagging agent, and a conductive inhibitor, and stir for 10 minutes; (6) Reduce the speed to 200 rpm, add a latent curing agent, and then stir at a low speed for 10 minutes, controlling the stirring temperature at 30℃-40℃; (7) Discharge the material under air pressure, and then grind it five times on a hydraulic three-roll mill until it reaches about 1 micrometer before discharging; (8) Vacuum degassing; (9) Gradient heating curing.

10. A method for preparing the black insulating resistance ink as described in claim 9, characterized in that, The gradient heating curing includes pre-curing at 25℃-80℃, main curing at 80℃-180℃, and post-curing at 180℃-200℃. The gradient curing time distribution and heating rate are calculated as follows: 。

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