Conductive ink for ink-jet printing and preparation method thereof

Abstract

The invention discloses conductive ink for ink-jet printing and a preparation method thereof. Comprising the following steps: step 1, dissolving bisphenol F type epoxy resin in dimethyl nylon acid, stirring for 10-15 minutes until the bisphenol F type epoxy resin is completely dissolved, then adding modified composite filler, methyl tetrahydrophthalic anhydride, a dispersing agent and a flatting agent, and continuously stirring for 20-30 minutes to obtain a mixed solution; 2, the mixed solution is subjected to ultrasonic treatment for 30-40 min till no macroscopic particles exist, and the conductive ink is obtained. The conductive ink has the beneficial effects that the epoxy resin is mixed with the modified composite filler, the methyl tetrahydrophthalic anhydride and the like, and ultrasonic treatment is performed to prepare the conductive ink; according to the conductive ink, the MXene and the carbon nanotubes are adopted to construct a three-dimensional conductive network, and the dispersity and the interface bonding force of the filler are improved through surface modification, so that the conductivity and the mechanical strength of the ink are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of inks, and specifically relates to a conductive ink for inkjet printing and a preparation method thereof. Background Art

[0002] In recent years, inkjet printing technology has been increasingly widely used in the fields of flexible electronics, intelligent packaging, printed circuit boards, etc., posing higher requirements for the performance of conductive inks. Traditional conductive inks usually use metal nanoparticles such as silver and copper as conductive fillers. Although they have high conductivity, they have defects such as high cost, easy oxidation, and poor mechanical properties. In addition, the dispersibility of metal fillers in the ink is poor and they are prone to agglomeration, resulting in insufficient uniformity and stability of the printed pattern, affecting the actual application effect.

[0003] To overcome the above problems, researchers have begun to explore carbon-based materials (such as carbon nanotubes and graphene) as conductive fillers. However, a single carbon material is difficult to form a continuous three-dimensional conductive network in the ink, with limited conductivity, and the interfacial bonding force with the resin matrix is weak, resulting in insufficient mechanical strength and durability of the ink. In addition, existing conductive inks also have obvious shortcomings in flame retardancy and long-term stability, and it is difficult to meet the requirements of high-end electronic devices.

[0004] Therefore, to solve the above problems, the present invention provides a conductive ink for inkjet printing and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a conductive ink for inkjet printing and a preparation method thereof.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A preparation method of a conductive ink for inkjet printing includes the following steps:

[0008] Step 1: Dissolve bisphenol F type epoxy resin in dimethyl nylon acid ester, stir for 10 - 15 min until completely dissolved, then add modified composite filler, methyltetrahydrophthalic anhydride, dispersant, and leveling agent, and continue to stir for 20 - 30 min to obtain a mixed solution;

[0009] Step 2: Ultrasonically treat the mixed solution for 30 - 40 min until no particles visible to the naked eye remain to obtain the conductive ink.

[0010] More preferably, the mixed solution includes the following components: by weight, 10 - 12 parts of bisphenol F type epoxy resin, 25 - 28 parts of dimethyl nylon acid ester, 10 - 12 parts of modified composite filler, 3 - 4 parts of methyltetrahydrophthalic anhydride, 0.3 - 0.4 part of dispersant, and 0.2 - 0.3 part of leveling agent.

[0011] Preferably, the preparation process of the modified composite filler is as follows:

[0012] A1: Mix lithium fluoride and hydrochloric acid, stir for 20 - 30 min, then add Ti 3 AlC 2 powder, raise the temperature to 40 - 50 °C, react for 48 h. After the reaction is completed, adjust the pH value to 7, perform ultrasonic treatment for 20 - 30 min, centrifuge, and collect the supernatant to obtain the MXene dispersion;

[0013] A2: Under a protective atmosphere, mix carbon nanotubes, the MXene dispersion, sodium dodecyl sulfate, and deionized water, perform ultrasonic treatment for 30 - 40 min, add melamine foam, dry in vacuum for 1 - 2 h, and then freeze - dry for 48 h to obtain the composite filler;

[0014] A3: Under a protective atmosphere, ultrasonically disperse the composite filler in ethanol, add a mixed solution of 3 - mercaptopropyltrimethoxysilane and methanol and ammonia water, raise the temperature to 30 - 40 °C, react for 1 - 2 h. After the reaction is completed, filter, wash, and dry to obtain the mercapto - modified composite filler;

[0015] A4: Under a protective atmosphere, disperse the mercapto - modified composite filler in toluene, add the modifier and benzoyl peroxide, raise the temperature to 60 - 70 °C, react for 1 - 2 h. After the reaction is completed, cool to room temperature, centrifuge, wash, and dry in vacuum to obtain the modified composite filler.

[0016] In the scheme, through acidic etching (LiF + HCl generates HF), Ti 3 AlC 2 is converted into two - dimensional conductive MXene, and then a three - dimensional conductive network is constructed with carbon nanotubes (CNT) assisted by sodium dodecyl sulfate, and the structure is fixed by the melamine foam template. Subsequently, 3 - mercaptopropyltrimethoxysilane is used to modify the surface of the filler with mercapto groups, and finally, the modifier containing 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide / imidazole is covalently grafted onto the surface of the filler through a free - radical - initiated thiol - ene click reaction. This design significantly improves the dispersibility, antioxidant property, and interfacial bonding force with epoxy resin of the filler, making the conductive ink have both high conductivity (MXene / CNT synergistic conduction), long - term stability (the modifier protects MXene), and flame retardancy (the 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide structure), and at the same time optimizing the leveling performance of inkjet printing.

[0017] Preferably, the raw materials of the MXene dispersion include the following components: by weight, 10 - 20 parts of lithium fluoride, 100 - 150 parts of hydrochloric acid, 5 - 10 parts of Ti 3 AlC 2 powder; among them, the concentration of hydrochloric acid is 6 mol / L;

[0018] Preferably, the composite filler comprises the following components: by weight, 5-10 parts of carbon nanotubes, 100-120 parts of MXene dispersion, 1-3 parts of sodium dodecyl sulfate, 200-250 parts of deionized water, and 50-60 parts of melamine foam.

[0019] Preferably, the raw material of the mercapto-functionalized composite filler comprises the following components: by weight, 100-120 parts of composite filler, 300-350 parts of ethanol, 10-20 parts of 3-mercaptopropyltrimethoxysilane, 50-60 parts of methanol, and 5-6 parts of ammonia water; wherein, the concentration of ammonia water is 2.5-5 mol / L.

[0020] Preferably, the raw material of the modified composite filler comprises the following components: by weight, 100-120 parts of mercapto-functionalized composite filler, 200-250 parts of toluene, 20-30 parts of modifier, and 1-3 parts of benzoyl peroxide.

[0021] Preferably, the preparation process of the modifier is as follows:

[0022] S1: Mix p-hydroxybenzaldehyde, potassium carbonate, and N,N-dimethylformamide, stir ultrasonically for 30-40 min, add 4-chloro-1-butene, under a protective atmosphere, raise the temperature to 60-70 °C, react for 10-12 h, after the reaction is completed, pour the reaction solution into ice water, extract with ethyl acetate, dry the organic phase and purify by column chromatography to obtain intermediate A;

[0023] S2: Mix 1-(3-aminopropyl)imidazole with absolute ethanol, stir evenly at room temperature, under a protective atmosphere, add the mixed solution of intermediate A and absolute ethanol, raise the temperature to 60-70 °C, react for 1-2 h, cool to room temperature, and evaporate the solvent under vacuum to obtain intermediate B;

[0024] S3: Mix intermediate B with absolute ethanol, stir for 60 min, add the mixed solution of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and absolute ethanol, react at room temperature for 9-10 h, filter the reaction product by vacuum distillation, and recrystallize to obtain the modifier.

[0025] In the scheme, p-hydroxybenzaldehyde undergoes a nucleophilic substitution reaction with 4-chloro-1-butene under alkaline conditions to form intermediate A with an allyl ether structure. The specific reaction process is as follows:

[0026]

[0027] In the scheme, the aldehyde group of intermediate A undergoes a condensation reaction with the amino group of 1-(3-aminopropyl)imidazole to form an imine (C=N). The specific reaction process is as follows:

[0028]

[0029] In the scheme, the imine double bond of intermediate B undergoes a nucleophilic addition reaction with the P-H bond of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to obtain a modifier; its structural formula is as follows:

[0030]

[0031] Preferably, the raw materials of intermediate A include the following components: by weight, 10-12 parts of p-hydroxybenzaldehyde, 22-24 parts of potassium carbonate, 100-120 parts of N,N-dimethylformamide, and 8-9 parts of 4-chloro-1-butene;

[0032] The raw materials of intermediate B include the following components: by weight, 11-13 parts of 1-(3-aminopropyl)imidazole, 150-200 parts of absolute ethanol, and 14-16 parts of intermediate A;

[0033] The raw materials of the modifier include the following components: by weight, 24-15 parts of intermediate B, 120-150 parts of absolute ethanol, and 17-19 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0034] Advantages of the present invention:

[0035] In the present invention, an epoxy resin is mixed with a modified composite filler, methyltetrahydrophthalic anhydride, etc., and a conductive ink is prepared by ultrasonic treatment; the conductive ink constructs a three-dimensional conductive network using MXene and carbon nanotubes, and improves the dispersibility and interfacial bonding force of the filler through surface modification, effectively improving the conductivity and mechanical strength of the ink. Specifically as follows:

[0036] First: In the scheme, a three-dimensional conductive network is constructed through the synergistic effect of MXene two-dimensional material and carbon nanotube one-dimensional material. Among them, melamine foam is used as a key template material, and its unique porous structure provides an ideal loading space for MXene and carbon nanotubes. The three-dimensional stereoscopic structure of the filler is effectively maintained through vacuum drying and freeze-drying processes. This porous support structure not only significantly increases the dispersion uniformity of the conductive filler, but also ensures the integrity and connectivity of the conductive network in the ink system. Combined with the reduction effect of mercapto modification and modifier grafting on the interfacial contact resistance, the electron transport channel is made smoother, thereby achieving excellent conductivity;

[0037] Second: In the solution, the active groups in the prepared modifier form a chemical cross-linked network with the epoxy resin. At the same time, the porous structure formed by the melamine foam template increases the surface roughness of the filler, generating a mechanical interlocking effect. This dual mechanism of chemical bonding and physical anchoring significantly improves the interfacial bonding strength between the ink and the substrate, enabling it to exhibit excellent adhesion and mechanical durability in flexible electronic applications. Detailed implementation mode

[0038] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0039] Embodiment 1: A preparation method of a conductive ink for inkjet printing, including the following steps:

[0040] Step 1: Dissolve 10 parts of bisphenol F type epoxy resin in 25 parts of dimethyl nylonate, stir for 10 min until completely dissolved, then add 10 parts of modified composite filler, 3 parts of methyltetrahydrophthalic anhydride, 0.3 part of dispersant, and 0.2 part of leveling agent, and continue to stir for 20 min to obtain a mixed solution;

[0041] Step 2: Ultrasonically treat the mixed solution for 30 min until no visible particles are present to obtain the conductive ink;

[0042] Among them, the preparation process of the modified composite filler is as follows:

[0043] A1: Mix 10 parts of lithium fluoride and 100 parts of hydrochloric acid (concentration 6 mol / L), stir for 20 min, then add 5 parts of Ti 3 AlC 2 powder, raise the temperature to 40 °C, react for 48 h. After the reaction is completed, adjust the pH value to 7, ultrasonically treat for 20 min, centrifuge, and collect the supernatant to obtain the MXene dispersion;

[0044] A2: Under a protective atmosphere, mix 5 parts of carbon nanotubes, 100 parts of MXene dispersion, 1 part of sodium dodecyl sulfate, and 200 parts of deionized water, ultrasonically treat for 30 min, add 50 parts of melamine foam, vacuum dry for 1 h, and then freeze dry for 48 h to obtain the composite filler;

[0045] A3: Under a protective atmosphere, 100 parts of the composite filler are ultrasonically dispersed in 300 parts of ethanol. Then, a mixed solution of 10 parts of 3-mercaptopropyltrimethoxysilane and 50 parts of methanol and 5 parts of ammonia water (concentration: 5 mol / L) are added. The temperature is raised to 30 °C and the reaction is carried out for 1 h. After the reaction ends, filtration, washing, and drying are performed to obtain the mercapto-functionalized composite filler.

[0046] A4: Under a protective atmosphere, 100 parts of the mercapto-functionalized composite filler are dispersed in 200 parts of toluene. Then, 20 parts of the modifier and 1 part of benzoyl peroxide are added. The temperature is raised to 60 °C and the reaction is carried out for 1 h. After the reaction ends, it is cooled to room temperature, and centrifugation, washing, and vacuum drying are performed to obtain the modified composite filler.

[0047] Among them, the preparation process of the modifier is as follows:

[0048] S1: 10 parts of p-hydroxybenzaldehyde, 22 parts of potassium carbonate, and 100 parts of N,N-dimethylformamide are mixed and ultrasonically stirred for 30 min. Then, 8 parts of 4-chloro-1-butene are added. Under a protective atmosphere, the temperature is raised to 60 °C and the reaction is carried out for 10 h. After the reaction ends, the reaction solution is poured into ice water, extracted with ethyl acetate, and the organic phase is dried and purified by column chromatography to obtain intermediate A.

[0049] S2: 11 parts of 1-(3-aminopropyl)imidazole and 80 parts of absolute ethanol are mixed and stirred evenly at room temperature. Under a protective atmosphere, a mixed solution of 14 parts of intermediate A and 70 parts of absolute ethanol is added. The temperature is raised to 60 °C and the reaction is carried out for 1 h. After cooling to room temperature, the solvent is evaporated under vacuum to obtain intermediate B.

[0050] S3: 24 parts of intermediate B and 60 parts of absolute ethanol are mixed. After stirring for 60 min, a mixed solution of 17 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 60 parts of absolute ethanol is added, and the reaction is carried out at room temperature for 9 h. The reaction product is filtered by vacuum distillation and recrystallized to obtain the modifier.

[0051] Example 2: A preparation method of conductive ink for inkjet printing, comprising the following steps:

[0052] Step 1: 12 parts of bisphenol F type epoxy resin are dissolved in 28 parts of dimethyl nylonate and stirred for 15 min until completely dissolved. Then, 12 parts of the modified composite filler, 4 parts of methyltetrahydrophthalic anhydride, 0.4 part of dispersant, and 0.3 part of leveling agent are added, and stirring is continued for 30 min to obtain a mixed solution.

[0053] Step 2: The mixed solution is ultrasonically treated for 40 min until no visible particles are present to obtain the conductive ink.

[0054] Among them, the preparation process of the modified composite filler is as follows:

[0055] A1: Mix 20 parts of lithium fluoride and 150 parts of hydrochloric acid (concentration: 6 mol / L), stir for 30 min, then add 10 parts of Ti 3 AlC 2 powder, raise the temperature to 50 °C, react for 48 h. After the reaction is completed, adjust the pH value to 7, perform ultrasonic treatment for 30 min, centrifuge, collect the supernatant to obtain the MXene dispersion;

[0056] A2: Under a protective atmosphere, mix 10 parts of carbon nanotubes, 120 parts of the MXene dispersion, 3 parts of sodium dodecyl sulfate, and 250 parts of deionized water, perform ultrasonic treatment for 40 min, add 60 parts of melamine foam, dry in vacuum for 2 h, and then freeze-dry for 48 h to obtain the composite filler;

[0057] A3: Under a protective atmosphere, ultrasonically disperse 120 parts of the composite filler in 350 parts of ethanol, add a mixed solution of 20 parts of 3-mercaptopropyltrimethoxysilane and 60 parts of methanol and 6 parts of ammonia water (concentration: 5 mol / L), raise the temperature to 40 °C, react for 2 h. After the reaction ends, filter, wash, and dry to obtain the mercapto-functionalized composite filler;

[0058] A4: Under a protective atmosphere, disperse 120 parts of the mercapto-functionalized composite filler in 250 parts of toluene, add 30 parts of the modifier and 3 parts of benzoyl peroxide, raise the temperature to 70 °C, react for 2 h. After the reaction ends, cool to room temperature, centrifuge, wash, and dry in vacuum to obtain the modified composite filler;

[0059] Among them, the preparation process of the modifier is as follows:

[0060] S1: Mix 12 parts of p-hydroxybenzaldehyde, 24 parts of potassium carbonate, and 120 parts of N,N-dimethylformamide, perform ultrasonic stirring for 40 min, add 9 parts of 4-chloro-1-butene. Under a protective atmosphere, raise the temperature to 70 °C, react for 12 h. After the reaction ends, pour the reaction solution into ice water, extract with ethyl acetate, dry the organic phase, and purify by column chromatography to obtain intermediate A;

[0061] S2: Mix 13 parts of 1-(3-aminopropyl)imidazole with 100 parts of absolute ethanol, stir evenly at room temperature. Under a protective atmosphere, add a mixed solution of 16 parts of intermediate A and 100 parts of absolute ethanol, raise the temperature to 70 °C, react for 2 h, cool to room temperature, and evaporate the solvent in vacuum to obtain intermediate B;

[0062] S3: Mix 15 parts of intermediate B with 70 parts of absolute ethanol, stir for 60 min, then add a mixed solution of 19 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 80 parts of absolute ethanol, react at room temperature for 10 h. The reaction product is filtered by vacuum distillation and recrystallized to obtain the modifier.

[0063] Example 3: A preparation method of conductive ink for inkjet printing, comprising the following steps:

[0064] Step 1: Dissolve 11 parts of bisphenol F-type epoxy resin in 26.5 parts of dimethyl nylonate, stir for 12.5 min until completely dissolved, then add 11 parts of modified composite filler, 3.5 parts of methyltetrahydrophthalic anhydride, 0.35 part of dispersant, and 0.25 part of leveling agent, and continue to stir for 25 min to obtain a mixed solution;

[0065] Step 2: Ultrasonically process the mixed solution for 35 min until no particles visible to the naked eye remain to obtain the conductive ink;

[0066] Among them, the preparation process of the modified composite filler is as follows:

[0067] A1: Mix 15 parts of lithium fluoride and 125 parts of hydrochloric acid (concentration 6 mol / L), stir for 25 min, then add 7.5 parts of Ti 3 AlC 2 powder, raise the temperature to 45 °C, react for 48 h, after the reaction is completed, adjust the pH value to 7, ultrasonically process for 25 min, centrifuge, collect the supernatant to obtain the MXene dispersion;

[0068] A2: Under a protective atmosphere, mix 7.5 parts of carbon nanotubes, 110 parts of MXene dispersion, 2 parts of sodium dodecyl sulfate, and 225 parts of deionized water, ultrasonically process for 35 min, add 55 parts of melamine foam, vacuum dry for 1.5 h, and then freeze dry for 48 h to obtain the composite filler;

[0069] A3: Under a protective atmosphere, ultrasonically disperse 110 parts of the composite filler in 325 parts of ethanol, add a mixed solution of 15 parts of 3-mercaptopropyltrimethoxysilane and 55 parts of methanol and 5.5 parts of ammonia water (concentration 5 mol / L), raise the temperature to 35 °C, react for 1.5 h, after the reaction ends, filter, wash, and dry to obtain the mercapto-functionalized composite filler;

[0070] A4: Under a protective atmosphere, disperse 110 parts of the mercapto-functionalized composite filler in 225 parts of toluene, add 25 parts of the modifier and 2 parts of benzoyl peroxide, raise the temperature to 65 °C, react for 1.5 h, after the reaction ends, cool to room temperature, centrifuge, wash, and vacuum dry to obtain the modified composite filler;

[0071] Among them, the preparation process of the modifier is as follows:

[0072] S1: Mix 11 parts of p-hydroxybenzaldehyde, 23 parts of potassium carbonate, and 110 parts of N,N-dimethylformamide, stir ultrasonically for 35 min, add 8.5 parts of 4-chloro-1-butene, under a protective atmosphere, raise the temperature to 65 °C, react for 11 h. After the reaction is completed, pour the reaction solution into ice water, extract with ethyl acetate, dry the organic phase, and purify by column chromatography to obtain intermediate A;

[0073] S2: Mix 12 parts of 1-(3-aminopropyl)imidazole with 90 parts of absolute ethanol, stir evenly at room temperature, under a protective atmosphere, add a mixed solution of 15 parts of intermediate A and 85 parts of absolute ethanol, raise the temperature to 65 °C, react for 1.5 h, cool to room temperature, and evaporate the solvent under vacuum to obtain intermediate B;

[0074] S3: Mix 19.5 parts of intermediate B with 65 parts of absolute ethanol, stir for 60 min, then add a mixed solution of 18 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 70 parts of absolute ethanol, react at room temperature for 9.5 h. The reaction product is filtered by vacuum distillation and recrystallized to obtain the modifier.

[0075] Comparative Example 1: Mix the MXene dispersion and carbon nanotubes as the composite filler to replace the modified composite filler, and the rest is the same as in Example 3, specifically as follows:

[0076] Step 1: Dissolve 11 parts of bisphenol F-type epoxy resin in 26.5 parts of dimethyl nylonate, stir for 12.5 min until completely dissolved, then add 11 parts of the composite filler, 3.5 parts of methyltetrahydrophthalic anhydride, 0.35 part of dispersant, and 0.25 part of leveling agent, and continue to stir for 25 min to obtain a mixed solution;

[0077] Step 2: Ultrasonically treat the mixed solution for 35 min until no visible particles are present to obtain the conductive ink;

[0078] Among them, the preparation process of the modified composite filler is as follows:

[0079] A1: Mix 15 parts of lithium fluoride and 125 parts of hydrochloric acid (concentration 6 mol / L), stir for 25 min, then add 7.5 parts of Ti 3 AlC 2 powder, raise the temperature to 45 °C, react for 48 h. After the reaction is completed, adjust the pH value to 7, ultrasonically treat for 25 min, centrifuge, and collect the supernatant to obtain the MXene dispersion;

[0080] A2: Under a protective atmosphere, mix 7.5 parts of carbon nanotubes, 110 parts of MXene dispersion, 2 parts of sodium dodecyl sulfate, and 225 parts of deionized water, and ultrasonically treat for 35 min to obtain the composite filler.

[0081] Comparative Example 2: The surface of the melamine foam was not modified, and the rest was the same as in Example 3. Specifically as follows:

[0082] Step 1: Dissolve 11 parts of bisphenol F-type epoxy resin in 26.5 parts of dimethyl nylonate, stir for 12.5 min until completely dissolved, then add 11 parts of composite filler, 3.5 parts of methyltetrahydrophthalic anhydride, 0.35 part of dispersant, and 0.25 part of leveling agent, and continue to stir for 25 min to obtain a mixed solution;

[0083] Step 2: Ultrasonically treat the mixed solution for 35 min until no particles are visible to the naked eye to obtain conductive ink;

[0084] Among them, the preparation process of the modified composite filler is as follows:

[0085] A1: Mix 15 parts of lithium fluoride and 125 parts of hydrochloric acid (concentration 6 mol / L), stir for 25 min, then add 7.5 parts of Ti 3 AlC 2 powder, raise the temperature to 45 °C, react for 48 h, after the reaction is completed, adjust the pH value to 7, ultrasonically treat for 25 min, centrifuge, collect the supernatant to obtain an MXene dispersion;

[0086] A2: Under a protective atmosphere, mix 7.5 parts of carbon nanotubes, 110 parts of MXene dispersion, 2 parts of sodium dodecyl sulfate, and 225 parts of deionized water, ultrasonically treat for 35 min, add 55 parts of melamine foam, vacuum dry for 1.5 h, and then freeze dry for 48 h to obtain a composite filler.

[0087] Detection test: Uniformly coat the conductive inks obtained in the examples and comparative examples on a PET substrate, cure at 80 °C for 3 h to obtain conductive samples; conduct the following detection tests:

[0088] (1) Measure the surface resistance by the I-V method;

[0089] (2) Refer to the method described in Standard GB7124-86 and test the shear strength on a universal tensile machine;

[0090] (3) Refer to GB / T15442.2 to detect the fire resistance time.

[0091] The data obtained are shown in the following table:

[0092]

[0093] Table 1

[0094] Conclusion: In the present invention, a conductive ink is prepared by mixing bisphenol F type epoxy resin with modified composite fillers, methyltetrahydrophthalic anhydride, etc., and subjecting the mixture to ultrasonic treatment. The ink constructs a three-dimensional conductive network using MXene and carbon nanotubes, and improves the dispersion and interfacial bonding force of the fillers through surface modification, significantly enhancing the conductivity and mechanical strength. Experimental data shows that the resistance of the conductive inks in Examples 1 to 3 is as low as 3.42×10 -3 Ω·cm, the shear strength is as high as 9.9 MPa, and the fire resistance time exceeds 24 minutes. However, due to the non-use of modified composite fillers or the lack of surface modification in Comparative Examples 1 and 2, the performance is significantly worse, and the resistance increases to 6.78×10 -3 Ω·cm, and the shear strength and fire resistance time also decrease. This indicates that the conductive ink of the present invention exhibits excellent performance in terms of conductivity, mechanical strength, and flame retardancy, and is suitable for inkjet printing applications.

[0095] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0096] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing conductive ink for inkjet printing, characterized in that: The following steps are involved: Step 1: dissolve bisphenol F epoxy resin in dimethyl nylonate, stir for 10-15 minutes until completely dissolved, then add modified composite filler, methyltetrahydrophthalic anhydride, dispersant, and leveling agent, continue stirring for 20-30 minutes to obtain a mixed solution; Step 2: Ultrasonicate the mixed solution for 30-40 minutes until no particles are visible to the naked eye to obtain conductive ink.

2. The method for preparing a conductive ink for inkjet printing according to claim 1, characterized in that: The mixed solution comprises the following components: by weight, 10-12 parts of bisphenol F epoxy resin, 25-28 parts of dimethyl nylonate, 10-12 parts of modified composite filler, 3-4 parts of methyltetrahydrophthalic anhydride, 0.3-0.4 parts of dispersant, and 0.2-0.3 parts of leveling agent.

3. The method for preparing a conductive ink for inkjet printing according to claim 1, characterized in that: The preparation process of the modified composite filler is: A1: Mix lithium fluoride and hydrochloric acid, stir for 20-30 minutes, then add Ti3AlC2 powder, raise the temperature to 40-50°C, react for 48 hours, after the reaction is completed, adjust the pH value to 7, ultrasonically treat for 20-30 minutes, centrifuge, collect the supernatant, and obtain MXene dispersion; A2: In a protective atmosphere, carbon nanotubes, MXene dispersion, sodium dodecyl sulfate and deionized water were mixed, ultrasonically treated for 30-40 minutes, melamine foam was added, vacuum dried for 1-2 hours, and then freeze-dried for 48 hours to obtain a composite filler; A3: Under a protective atmosphere, the composite filler is ultrasonically dispersed in ethanol, a mixed solution of 3-mercaptopropyltrimethoxysilane and methanol and ammonia water are added, the temperature is raised to 30-40°C, and the reaction is carried out for 1-2 hours. After the reaction is completed, the composite filler is filtered, washed, and dried to obtain a thiolated composite filler; A4: Under a protective atmosphere, the thiolated composite filler is dispersed in toluene, a modifier and benzoyl peroxide are added, the temperature is raised to 60-70°C, and the reaction is carried out for 1-2 hours. After the reaction is completed, the mixture is cooled to room temperature, centrifuged, washed, and vacuum dried to obtain a modified composite filler.

4. The method for preparing a conductive ink for inkjet printing according to claim 3, characterized in that: The MXene dispersion raw material includes the following components: by weight, 10-20 parts of lithium fluoride, 100-150 parts of hydrochloric acid, and 5-10 parts of Ti3AlC2 powder; wherein the concentration of hydrochloric acid is 6 mol / L.

5. The method for preparing a conductive ink for inkjet printing according to claim 3, characterized in that: The composite filler comprises the following components: by weight, 5-10 parts of carbon nanotubes, 100-120 parts of MXene dispersion, 1-3 parts of sodium dodecyl sulfate, 200-250 parts of deionized water, and 50-60 parts of melamine foam.

6. The method for preparing a conductive ink for inkjet printing according to claim 3, characterized in that: The thiolated composite filler raw material comprises the following components: by weight, 100-120 parts of composite filler, 300-350 parts of ethanol, 10-20 parts of 3-mercaptopropyltrimethoxysilane, 50-60 parts of methanol, and 5-6 parts of ammonia water; wherein the concentration of the ammonia water is 2.5-5 mol / L.

7. The method for preparing a conductive ink for inkjet printing according to claim 3, characterized in that: The modified composite filler raw material comprises the following components: by weight, 100-120 parts of thiolated composite filler, 200-250 parts of toluene, 20-30 parts of modifier, and 1-3 parts of benzoyl peroxide.

8. The method for preparing a conductive ink for inkjet printing according to claim 3, characterized in that: The preparation process of the modifier is: S1: p-Hydroxybenzaldehyde, potassium carbonate and N,N-dimethylformamide were mixed, ultrasonically stirred for 30-40 min, 4-chloro-1-butene was added, and the temperature was raised to 60-70°C under a protective atmosphere, and the reaction was carried out for 10-12 h. After the reaction was completed, the reaction solution was poured into ice water, extracted with ethyl acetate, and the organic phase was dried and purified by column chromatography to obtain intermediate A; S2: 1-(3-aminopropyl)imidazole and anhydrous ethanol were mixed, stirred evenly at room temperature, and a mixed solution of intermediate A and anhydrous ethanol was added under a protective atmosphere, the temperature was raised to 60-70°C, the reaction was carried out for 1-2h, the mixture was cooled to room temperature, and the solvent was evaporated in vacuo to obtain intermediate B; S3: Mix the intermediate B with anhydrous ethanol, stir for 60 minutes, add a mixed solution of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and anhydrous ethanol, react at room temperature for 9-10 hours, filter the reaction product by vacuum distillation, and recrystallize to obtain a modifier.

9. The method for preparing a conductive ink for inkjet printing according to claim 8, characterized in that: The intermediate A raw material comprises the following components: by weight, 10-12 parts of p-hydroxybenzaldehyde, 22-24 parts of potassium carbonate, 100-120 parts of N,N-dimethylformamide, and 8-9 parts of 4-chloro-1-butene; The intermediate B raw material comprises the following components: by weight, 11-13 parts of 1-(3-aminopropyl)imidazole, 150-200 parts of anhydrous ethanol, and 14-16 parts of intermediate A; The modifier raw material comprises the following components: by weight, 24-15 parts of intermediate B, 120-150 parts of anhydrous ethanol, and 17-19 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

10. Conductive ink obtained according to the method for preparing conductive ink for inkjet printing according to any one of claims 1 to 9.

Images