Modified graphene, preparation method thereof and friction-resistant ink

Abstract

The invention relates to the field of modified graphene, and particularly discloses modified graphene, a preparation method thereof and friction-resistant ink. The preparation method comprises the following steps: modifying graphene, so that the graphene has relatively good dispersity and relatively high electropositivity and adhesive force, can be relatively well dispersed in the printing ink and can be tightly adsorbed and wound with anionic dyes and macromolecules in the printing ink, and the cohesion of the printing ink is effectively improved, so that the friction resistance of the printing ink is improved; the conductive ink is suitable for ink containing anionic dyes, especially containing sodium alginate modified carbon black, and the prepared ink can keep a stable conductive effect under friction of external force.

Description

Technical Field

[0001] The present application relates to the field of modified graphene, and more specifically, to a modified graphene and a preparation method thereof and friction-resistant ink. Background Art

[0002] Graphene is a two-dimensional material composed of carbon atoms. It has excellent electrical and thermal conductivity, low resistance and high tensile strength. It is widely used in the printing and electronics industries. The ink made of graphene has efficient thermal conduction, energy saving effect and electrospray printing function. It also has good color expression and has been widely used in the fields of thermoelectric nanomaterials, chips, cables, screen protectors, etc. However, due to the high surface energy and a large number of oxide functional groups of graphene, the dispersion of graphene in the ink is not good, and it cannot achieve a good cohesion effect with the ink system. When it is scratched by external force, it will also cause the conductive ink to fail due to adsorption due to van der Waals force. The wear resistance of the ink is mainly reflected in the cohesion of the ink and the adhesion to the substrate. When graphene cannot be evenly and stably compatible with the ink system, the friction resistance of the ink cannot meet the use requirements well.

[0003] In view of the above-mentioned related issues, how to obtain a modified graphene suitable for a colored ink system is an issue that needs to be solved urgently. Summary of the invention

[0004] In order to obtain a graphene suitable for preparing colored conductive ink to improve the friction resistance of the ink, the present application provides a modified graphene and a preparation method thereof and a friction-resistant ink.

[0005] In a first aspect, the present application provides a method for preparing modified graphene, comprising the following preparation steps: adding graphene and a silane coupling agent to an ethanol aqueous solution, ultrasonically dispersing, heating to activate, filtering, adding an ethanol aqueous solution and polyetherimide, ultrasonically dispersing, heating to react, then adding iodoethane, heating for alkylation, filtering, washing, and drying to obtain modified graphene.

[0006] By adopting the above technical scheme, the preparation method is simple, the prepared modified graphene can be well dispersed in the ink, better play the conductive role, polyetherimide has good creep resistance, insulation and wear resistance, thereby improving the wear resistance of the ink. The modified graphene surface is grafted with relatively rich cationic quaternary ammonia, the cation concentration is high, and the electrostatic repulsion can improve the dispersion of graphene. It can also adsorb with the anionic dye in the ink. Under the adsorption effect, on the one hand, the dispersion of the dye is improved, and the coloring effect is improved. On the other hand, the macromolecular dye further modifies the graphene after electrostatic assembly, improves the compatibility of graphene in the system, and the steric hindrance effect of the macromolecule improves the dispersibility of the graphene particles. Through the force with the polymer resin of the connecting material, the cohesion and wear resistance of the ink are improved. The surface of the modified graphene is dehydrated by hydrolysis of the silicon oxygen bond, and the polyimide modification and alkylation form a large number of organic long chains, which greatly improves the compatibility of graphene in the system, and produces a certain entanglement with the polymer chain segment in the ink, the connection is tighter, the ink has strong cohesion, and good friction resistance. The modified graphene obtained by adopting the above technical solution can enhance the cohesive effect in the ink containing anionic dyes through the combination of anions and cations and the entanglement of chain segments, thereby greatly improving the friction resistance of the ink.

[0007] Preferably, the diameter of the graphene sheet is 0.5-5 μm and the thickness is 0.8-1.2 nm; the silane coupling agent is one or more of chloropropyltrimethoxysilane and chloropropyltriethoxysilane.

[0008] By adopting the above technical scheme, the graphene modification effect is better, the sheet diameter can realize effective overlap between graphene while being fully modified, the "bridge" effect is less, the tap density is higher, and it has a good conductive effect, which meets the use requirements of conductive ink. When the diameter-to-thickness ratio of graphene is larger, the compatibility of graphene with ink is not good, and it is easy to come out when rubbed. When the diameter-to-thickness ratio of graphene is smaller, it is not easy to realize the overlap of the conductive path, and the conductive effect is not good. When the sheet diameter of graphene is larger, it is not compatible with ink, and the ink prepared is not resistant to friction. When the sheet diameter of graphene is smaller, the dispersion effect is improved to a limited extent. At the same time, it may be that the quaternary ammonium chain segment on the modified graphene prepared at this time can carry enough positive charge to achieve good adsorption with anionic dyes. The length of the chain segment has a good entanglement effect with the macromolecules of the ink system, and will not cause the organic long chain to form more coatings on the graphene. The prepared graphene sheets can maintain good contact, and the prepared ink has good conductivity and appropriate viscosity, and can achieve strong infiltration and adhesion to the substrate.

[0009] Preferably, the temperature for heating activation is 80-90°C for 20-24 hours, the temperature for heating reaction is 80-90°C for 20-24 hours, and the temperature for heating alkylation is 80-90°C for 20-24 hours.

[0010] By adopting the above technical scheme, the modification effect of graphene is further optimized, with less by-products, and the modified graphene is evenly and fully quaternized, which can achieve better conductive path overlapping effect while having high positive charge and entangled chain segments.

[0011] In a second aspect, the present application provides a modified graphene prepared by the above method.

[0012] By adopting the above technical solution, the modified graphene obtained has good dispersibility in the ink, can form certain adsorption and cross-linking with the anionic dyes and macromolecules in the ink, has high cohesion and stable conductive effect.

[0013] In a third aspect, the present application provides a friction-resistant ink, comprising the following raw materials in parts by weight: 50-60 parts of a binder, 3-12 parts of modified graphene, 5-15 parts of sodium alginate modified carbon black, 3-10 parts of mineral oil, and 1-5 parts of an auxiliary agent. The binder includes a rosin-modified phenolic resin, and the auxiliary agent includes a desiccant. The modified graphene is the modified graphene mentioned above in this application.

[0014] By adopting the above technical scheme, the carbon black modified with sodium alginate has better adhesion and carries a certain negative charge. It can form a certain adsorption with the modified graphene evenly distributed in the ink and form a certain adhesion with the macromolecules in the system. The obtained ink has high cohesion, high adhesion to the substrate, and stable friction resistance and conductive effect.

[0015] Preferably, the rosin-modified phenolic resin is an epoxy grafted rosin-modified phenolic resin, which comprises the following preparation steps: heating and melting the rosin, adding phenol and magnesium oxide under nitrogen protection, dripping formaldehyde, heating to reflux, heating to react, cooling to add epichlorohydrin and a catalyst, reacting, distilling under reduced pressure, adding sodium hydroxide solution dripping with stirring, reacting, washing, and rotary distilling to obtain the epoxy grafted rosin-modified phenolic resin.

[0016] Any rosin-modified phenolic resin obtained by any modification method can be used in the scheme of the present application. By adopting the above technical scheme, the present application has a simple preparation method, few by-products, and high yield. The prepared epoxy grafted rosin-modified phenolic resin can achieve good connection with the components of the ink system in the present application, and the ink system has high cohesion and good friction resistance. The prepared epoxy grafted rosin-modified phenolic resin has excellent properties such as high hardness, wear resistance, and water resistance, and has good compatibility with the modified graphene prepared in the present application. At the same time, the surface has more active epoxy groups, which improves the adhesion of the ink. By cross-linking with the modified graphene to a certain extent, the cohesion of the prepared ink is further improved, and the friction resistance of the prepared ink is better, and the conductive effect is more stable.

[0017] Preferably, the rosin-modified phenolic resin is an epoxy-grafted rosin-modified phenolic resin, and the epoxy value is 0.20-0.24.

[0018] By adopting the above technical solution, the number of epoxy groups is appropriate, and the epoxy grafted rosin modified phenolic resin under this epoxy value is suitable for the component setting of the ink system of this application, and the friction resistance of the ink is most significantly improved.

[0019] Preferably, the mass ratio of modified graphene, sodium alginate modified carbon black, and epoxy grafted rosin modified phenolic resin is: (50-60): (8-11): 10.

[0020] Preferably, the mass ratio of modified graphene, sodium alginate modified carbon black, and epoxy grafted rosin modified phenolic resin is 55:9:10.

[0021] The applicant found during production that the ink produced at this mass ratio has the best friction resistance. This may be because the adsorption of modified graphene and sodium alginate modified carbon black, and the cross-linking and entanglement with rosin modified phenolic resin are better at this time. At the same time, the ink can also achieve good infiltration of the substrate, achieving a balance between the cohesion and adhesion properties of the ink.

[0022] Preferably, the preparation steps of sodium alginate modified carbon black include: S1: adding carbon black to a nitric acid aqueous solution, stirring for reaction, filtering, washing, and drying to obtain oxidized carbon black; S2: adding oxidized carbon black and an epoxy silane coupling agent to an ethanol aqueous solution, stirring evenly, heating for reaction, and obtaining modified carbon black; S3: dissolving sodium alginate in deionized water to obtain a sodium alginate aqueous solution, adding modified carbon black and sodium hydroxide, and heating for reaction to obtain sodium alginate modified carbon black.

[0023] The sodium alginate modified carbon black prepared by the above preparation steps has simple preparation steps, the carbon black is evenly distributed without agglomeration, has high adhesion performance and certain rheological properties, can evenly and stably improve the cohesion of the ink, and has better friction resistance.

[0024] Preferably, the sodium alginate modified carbon black and modified graphene are pretreated, and the pretreatment step includes: adding the sodium alginate modified carbon black and modified graphene to an ethanol aqueous solution, ultrasonically dispersing, filtering, and drying to obtain pretreated carbon black-graphene.

[0025] By pre-treating sodium alginate-modified carbon black and modified graphene, the two can be evenly and tightly adsorbed and assembled, and evenly distributed in the ink to achieve stable friction resistance and conductive effects.

[0026] In summary, this application has the following beneficial effects: The present application modifies graphene to make it have better dispersibility and higher positive charge, making it more suitable for use in inks containing anionic dyes. By limiting the graphene particle size, the dispersion of graphene in the ink is further improved, and it can also maintain good wetting on the substrate. The overlapping effect of the graphene sheet structure is better, and the prepared ink can stably maintain the conductive effect under friction.

[0027] The present application limits the binder in the ink to epoxy grafted rosin modified phenolic resin, so that the modified graphene can also undergo a certain degree of cross-linking with the binder of the ink, further improving the scratch resistance of the ink; limits the dye to sodium alginate modified carbon black so that the carbon black surface has more anions and higher adhesion; further limits the mass ratio and epoxy value of epoxy grafted rosin modified phenolic resin, modified graphene, and sodium alginate modified carbon black, so that the ink obtained is fully adsorbed, entangled, and cross-linked inside, has good wettability with the substrate, strong adhesion, good friction resistance, and can maintain stable conductive properties under external friction. DETAILED DESCRIPTION

[0028] To further help understand the technical solution of the present invention, the technical solution of the present invention is described in more detail below by providing several specific implementation examples. All of these described embodiments are only partial embodiments of the present invention, not all of them. The following specific embodiments and comparative examples may be combined with each other, and the same or similar concepts or processes therein may not be repeated in some embodiments; and the reaction devices, monomer compounds, etc. involved in the following embodiments and comparative examples are conventionally commercially available unless otherwise specified.

[0029] Graphene with an average flake diameter of 0.5-5 μm and a thickness of 0.8 nm was purchased from Pioneer Nano, with the item number: XF001W; graphene with an average flake diameter of 5-10 μm and a thickness of 4-20 nm was purchased from Juguang Evonik, with the item number: C03041; the desiccant was Lishengyuan 701, the rosin-modified phenolic resin was purchased from Yoshida Ink Resin 210; and polyetherimide was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0030] Preparation example: Epoxy grafted rosin modified phenolic resin: Preparation Example 1: Heat 60g of rosin to 170°C to melt, pass nitrogen protection, add 50g of phenol and 0.8g of magnesium oxide, drop 50g of formaldehyde, heat and reflux at 100°C for 3 hours, react at 200°C for 10 hours, cool to 100°C, add 40g of epichlorohydrin, keep warm for reaction, distill under reduced pressure, add 15g of 20wt% sodium hydroxide solution dropwise with stirring, react, wash with deionized water 3 times, and rotary evaporate to obtain epoxy grafted rosin modified phenolic resin.

[0031] The epoxy grafted rosin modified phenolic resin prepared in this preparation example has an epoxy value of 0.24, and epoxy grafted rosin modified phenolic resins with the same epoxy value prepared by other preparation methods are all acceptable.

[0032] Preparation Example 2: Heat 60g of rosin to 170°C and melt, pass nitrogen protection, add 53g of phenol and 0.8g of magnesium oxide, drop 50g of formaldehyde, heat and reflux at 100°C for 3 hours, react at 210°C for 12 hours, cool to 100°C, add 50g of epichlorohydrin, keep warm for reaction, distill under reduced pressure, add 15g of 20wt% sodium hydroxide solution dropwise with stirring, react, wash with deionized water 3 times, and rotary evaporate to obtain epoxy grafted rosin modified phenolic resin.

[0033] The epoxy grafted rosin modified phenolic resin prepared in this preparation example has an epoxy value of 0.27, and epoxy grafted rosin modified phenolic resins with the same epoxy value prepared by other preparation methods are all acceptable.

[0034] Sodium alginate modified carbon black: Preparation Example 3: S1: Add 60g of carbon black to 250ml of 25wt% nitric acid aqueous solution, disperse by ultrasonic at 300W for 30 minutes, react for 3 hours, filter, wash with deionized water 3 times, and dry at 50°C to obtain oxidized carbon black; S2: Add the oxidized carbon black prepared in S1 and 5 g of epoxysilane coupling agent KH-560 into 300 ml of 70 wt % ethanol aqueous solution, stir evenly, and heat at 45° C. for 2 hours to obtain modified carbon black; S3: Dissolve 3 g of sodium alginate in deionized water to obtain 300 ml of 1 wt% sodium alginate aqueous solution, add the modified carbon black prepared in S2 and 25 g of sodium hydroxide, heat at 100° C. for 2 hours, and filter to obtain sodium alginate modified carbon black. Example

[0035] Modified graphene: Example 1 5g of graphene and 4g of γ-chloropropyltrimethoxysilane were added to 350ml of 50vt% ethanol aqueous solution, ultrasonically dispersed at 300w for 7 minutes, heated at 85°C for activation for 22 hours, filtered, 350ml of 50vt% ethanol aqueous solution and 7g of polyetherimide were added, ultrasonically dispersed at 300w for 7 minutes, heated at 85°C for reaction for 22 hours, and then 3g of iodine was added, heated at 40°C for alkylation for 12 hours, filtered, washed with deionized water 3 times, and dried at 40°C to obtain modified graphene.

[0036] The graphene sheet in this embodiment has a diameter of 0.5-5 μm and a thickness of 0.8 nm, and is purchased from Pioneer Nano, with a serial number of XF001W.

[0037] Example 2 Add 5g of graphene and 3g of γ-chloropropyltrimethoxysilane to 350ml of 50vt% ethanol aqueous solution, ultrasonically disperse at 300w for 7 minutes, heat at 85℃ for activation for 22 hours, filter, add 350ml of 50vt% ethanol aqueous solution and 7g of polyetherimide, ultrasonically disperse at 300w for 7 minutes, heat at 85℃ for reaction for 22 hours, then add 3g of iodine, heat at 40℃ for alkylation for 12 hours, filter, wash with deionized water 3 times, and dry at 40℃ to obtain modified graphene.

[0038] The graphene sheet of this embodiment has a diameter of 5-10 μm and a thickness of 4-20 nm, and is purchased from Evonik, item number: C03041.

[0039] Friction-resistant ink: Embodiment 3: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 10 g of modified graphene prepared in Example 1, 10 g of sodium alginate modified carbon black prepared in Preparation Example 3, 10 g of mineral oil, and 5 g of desiccant.

[0040] The preparation steps are as follows: mix the components by mass, stir at a speed of 800 r / min for 30 minutes, stir at a speed of 1000 r / min for 10 minutes, let stand, and vacuum degas to obtain friction-resistant ink.

[0041] Embodiment 4: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 10 g of modified graphene prepared in Example 1, 10 g of sodium alginate modified carbon black prepared in Preparation Example 3, 10 g of mineral oil, and 5 g of desiccant.

[0042] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0043] Embodiment 5: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 3 g of modified graphene prepared in Example 1, 15 g of sodium alginate modified carbon black prepared in Preparation Example 3, 8 g of mineral oil, and 5 g of desiccant.

[0044] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0045] Embodiment 6: This embodiment includes the following raw materials in parts by weight: 55 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 12 g of modified graphene prepared in Example 1, 5 g of sodium alginate modified carbon black prepared in Preparation Example 3, 5 g of mineral oil, and 5 g of desiccant.

[0046] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0047] Embodiment 7: This embodiment includes the following raw materials in parts by weight: 55 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 7 g of modified graphene prepared in Example 1, 10 g of sodium alginate modified carbon black prepared in Preparation Example 3, 5 g of mineral oil, and 5 g of desiccant.

[0048] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0049] Embodiment 8: This embodiment includes the following raw materials in parts by weight: 55 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 8 g of modified graphene prepared in Example 1, 10 g of sodium alginate modified carbon black prepared in Preparation Example 3, 5 g of mineral oil, and 5 g of desiccant.

[0050] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0051] Embodiment 9: This embodiment includes the following raw materials in parts by mass: 55 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 9 g of modified graphene prepared in Example 1, 10 g of sodium alginate modified carbon black prepared in Preparation Example 3, 5 g of mineral oil, and 5 g of desiccant.

[0052] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0053] Embodiment 10: This embodiment includes the following raw materials in parts by weight: 55 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 1 g of modified graphene prepared in Example 1, 10 g of sodium alginate modified carbon black prepared in Preparation Example 3, 5 g of mineral oil, and 5 g of desiccant.

[0054] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0055] Embodiment 11: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 3 g of modified graphene prepared in Example 1, 15 g of carbon black, 8 g of mineral oil, and 5 g of desiccant.

[0056] The preparation steps are: S1: adding carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40° C. to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0057] Embodiment 12: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 3 g of modified graphene prepared in Example 2, 15 g of sodium alginate modified carbon black prepared in Preparation Example 3, 8 g of mineral oil, and 5 g of desiccant.

[0058] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0059] Embodiment 13: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 2, 3 g of modified graphene prepared in Example 1, 15 g of sodium alginate modified carbon black prepared in Preparation Example 3, 8 g of mineral oil, and 5 g of desiccant.

[0060] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0061] Embodiment 14: This embodiment includes the following raw materials in parts by mass: 50 g of rosin-modified phenolic resin, 3 g of modified graphene prepared in Example 1, 15 g of sodium alginate-modified carbon black prepared in Preparation Example 3, 8 g of mineral oil, and 5 g of desiccant.

[0062] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0063] Comparative Example Comparative Example 1: 5 g of graphene and 4 g of aminosilane coupling agent KH-550 were added to 350 ml of 50 vt% ethanol aqueous solution, ultrasonically dispersed at 300 w for 7 minutes, heated at 85 ° C for 22 hours, filtered, washed with deionized water 3 times, and dried at 40 ° C to obtain modified graphene.

[0064] The graphene sheet in this comparative example has a diameter of 0.5-5 μm and a thickness of 0.8 nm, and is purchased from Pioneer Nano, with a serial number of XF001W.

[0065] Comparative Example 2: This embodiment includes the following raw materials in parts by mass: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 3 g of modified graphene prepared in Comparative Example 1, 15 g of sodium alginate modified carbon black prepared in Preparation Example 3, 8 g of mineral oil, and 5 g of desiccant.

[0066] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0067] Comparative Example 3: This embodiment includes the following raw materials in parts by weight: 50 g of epoxy grafted rosin modified phenolic resin prepared in Preparation Example 1, 3 g of graphene, 15 g of sodium alginate modified carbon black prepared in Preparation Example 3, 8 g of mineral oil, and 5 g of desiccant.

[0068] The preparation steps are: S1: adding sodium alginate modified carbon black and modified graphene to 150 ml of 60 wt% ethanol aqueous solution, ultrasonically dispersing at 300 W for 1 hour, filtering, and drying at 40 ° C to obtain pretreated carbon black-graphene; S2: The pretreated carbon black-graphene and the remaining components are mixed by mass, stirred at a speed of 800 r / min for 30 minutes, and then stirred at a speed of 1000 r / min for 10 minutes, allowed to stand, and vacuum degassed to obtain friction-resistant ink.

[0069] The graphene sheet in this comparative example has a diameter of 0.5-5 μm and a thickness of 0.8 nm, and is purchased from Pioneer Nano, with a serial number of XF001W.

[0070] Performance testing 1. Adhesion - 100-grid test method: Take the ink samples prepared in each embodiment and each comparative example, apply them on PET, cure them, and then conduct the following test: use a 100-grid knife with a blade width of 10mm-12mm, 1mm-1.2mm intervals, and a total of 10 grids to cut 10×10 (100) 1mm×1mm small grids on the surface of the test sample. When the 100-grid knife is cut, it should cut to the bottom material, and it cannot cut only on the ink, otherwise the test will not be established; use a brush to brush the debris in the test area clean, then use 3M-600 tape to firmly stick to the tested small grid, and use an eraser to wipe the tape vigorously to increase the contact area and strength between the tape and the tested area; grab one end of the tape by hand, and quickly tear off the tape in the vertical direction (90°), and conduct the same test twice at the same position. The degree of ink shedding is used to determine whether it is qualified. The highest standard is 5B, which means no shedding, and the lowest is 0B, which means the shedding area is greater than 65wt%.

[0071] 2. Take the ink samples prepared in each embodiment and each comparative example respectively, coat a straight line on PET, connect batteries and light-emitting diodes on both sides after curing, and then conduct the following test: wrap American 0000# grade steel wool on a 2cm×2cm square column head, apply 500g pressure, rub distance 20mm, rub speed 50 times / min, rub back and forth on the ink line 100 times, observe the light emission of the diode, record yes if it emits light, and record no if it does not emit light.

[0072] The results are summarized in Table 1.

[0073] Table 1 Adhesion Luminous condition Adhesion Luminous condition Example 3 3B yes Example 10 3B no Example 4 4B yes Embodiment 11 2B yes Example 5 4B yes Example 12 3B yes Example 6 4B yes Example 13 3B yes Example 7 4B yes Embodiment 14 2B yes Example 8 4B yes Comparative Example 2 1B no Example 9 5B yes Comparative Example 3 0B no Combining Examples 3-4, Comparative Examples 2-3 and Table 1, it can be seen that the present application modifies graphene to have good dispersibility, high positive charge and long organic chain segments, which are suitable for anionic dye conductive inks. After pretreatment, the modified graphene and sodium alginate modified carbon black can achieve good adsorption and entanglement connection effects in the ink system, and the obtained ink has good friction resistance. Combining Examples 4 and 12 and Table 1, it can be seen that by limiting the particle size of graphene, the friction resistance and conductivity are better.

[0074] It can be seen from Examples 4 and 11 and Table 1 that by modifying carbon black with sodium alginate, the modified carbon black has richer negative charge and stronger adhesion, and the two are tightly connected after pretreatment, further improving the uniform dispersion and cohesion of the prepared ink.

[0075] It can be seen from Examples 4-10 and Table 1 that the present application limits the mass ratio of epoxy grafted rosin modified phenolic resin, modified graphene, and sodium alginate modified carbon black so that the cohesion of the modified graphene in the ink and the adhesion to the substrate achieve a good balance. The prepared ink will not fall off as a whole but the ink coating structure is destroyed by external force and the conductive failure is caused when it is rubbed due to sufficient adhesion but insufficient cohesion. It will not be separated from the substrate as a whole when rubbed by external force due to sufficient cohesion but insufficient adhesion.

[0076] It can be seen from Examples 5, 12-14 and Table 1 that the present application limits the binder to epoxy grafted rosin modified phenolic resin, and the modified graphene can further improve the stability in the ink system by entanglement and cross-linking with the binder. By limiting the epoxy value of the epoxy grafted rosin modified phenolic resin to a certain range, the degree of cross-linking is appropriate, and the complete debonding of the ink coating due to excessive cohesion and insufficient adhesion will not occur. After friction, the effect of stable conductivity can be maintained, and it is suitable for use in the fields of thermoelectric nanomaterials, chips, cables, screens, etc.

[0077] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing modified graphene, characterized in that: The method comprises the following preparation steps: adding graphene and a silane coupling agent to an ethanol aqueous solution, ultrasonically dispersing, heating and activating, filtering, adding an ethanol aqueous solution and polyetherimide, ultrasonically dispersing, heating and reacting, then adding iodoethane, heating and alkylating, filtering, washing, and drying to obtain modified graphene.

2. The method for preparing modified graphene according to claim 1, characterized in that: The sheet diameter of the graphene is 0.5-5 μm and the thickness is 0.8-1.2 nm; the silane coupling agent is one or more of chloropropyltrimethoxysilane and chloropropyltriethoxysilane.

3. The method for preparing modified graphene according to claim 1, characterized in that: The temperature of the heating activation is 80-90°C and the time is 20-24 hours, the temperature of the heating reaction is 80-90°C and the time is 20-24 hours, and the temperature of the heating alkylation is 80-90°C and the time is 20-24 hours.

4. A modified graphene, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 3.

5. A friction-resistant ink, characterized in that: The invention comprises the following raw materials in parts by mass: 50-60 parts of a connecting material, 3-12 parts of modified graphene, 5-15 parts of sodium alginate-modified carbon black, 3-10 parts of mineral oil, and 1-5 parts of an auxiliary agent, wherein the connecting material comprises rosin-modified phenolic resin, the auxiliary agent comprises a desiccant, and the modified graphene is the modified graphene described in claim 4.

6. The friction-resistant ink according to claim 5, characterized in that: The rosin-modified phenolic resin is an epoxy grafted rosin-modified phenolic resin, which comprises the following preparation steps: heating and melting the rosin, introducing nitrogen protection to add phenol and magnesium oxide, dripping formaldehyde, heating and refluxing, heating to react, cooling to add epichlorohydrin and a catalyst, reacting, distilling under reduced pressure, stirring and dripping a sodium hydroxide solution, reacting, washing, and rotary distilling to obtain the epoxy grafted rosin-modified phenolic resin.

7. The friction-resistant ink according to claim 6, characterized in that: The epoxy value of the epoxy grafted rosin modified phenolic resin is 0.20-0.

24.

8. The friction-resistant ink according to claim 5, characterized in that: The mass ratio of the epoxy grafted rosin modified phenolic resin, modified graphene and sodium alginate modified carbon black is: (50-60): (8-11):

10.

9. The friction-resistant ink according to claim 5, characterized in that: The preparation steps of the sodium alginate modified carbon black include: S1: adding carbon black to a nitric acid aqueous solution, stirring for reaction, filtering, washing, and drying to obtain oxidized carbon black; S2: adding oxidized carbon black and an epoxy silane coupling agent to an ethanol aqueous solution, stirring evenly, heating for reaction, and obtaining modified carbon black; S3: dissolving sodium alginate in deionized water to obtain a sodium alginate aqueous solution, adding modified carbon black and sodium hydroxide, and heating for reaction to obtain sodium alginate modified carbon black.

10. The friction-resistant ink according to claim 5, characterized in that: The sodium alginate modified carbon black and modified graphene are pretreated, and the pretreatment step includes: adding the sodium alginate modified carbon black and modified graphene into an ethanol aqueous solution, ultrasonically dispersing, filtering, and drying to obtain pretreated carbon black-graphene.