High temperature resistant non-yellowing polyarylene ether nitrile modified ink and method of making

Abstract

The present application relates to the technical field of ink preparation, and discloses a high-temperature-resistant and discoloration-resistant polyarylene ether nitrile modified ink and a preparation method thereof, the ink comprising a film-forming resin system, the film-forming resin system comprising polyarylene ether nitrile resin, epoxy resin and auxiliary resin; high-temperature-resistant inorganic pigment; antioxidant synergistic system; surface-modified nano inorganic barrier material; hydrolysable silane coupling type organic-inorganic hybrid precursor; curing agent; dispersant and rheological additive; wherein the antioxidant synergistic system comprises hindered phenolic antioxidant and phosphite auxiliary antioxidant; and the surface-modified nano inorganic barrier material is nano SiO2 modified by a silane coupling agent. The present application uses polyarylene ether nitrile as the main resin, optimizes the adhesion by epoxy modification, matches high-temperature-resistant inorganic pigment and anti-yellowing auxiliary agent, and controls moisture, dispersion uniformity and curing parameters throughout the process, so that the high-temperature-resistant and discoloration-resistant ink for automobile engine compartments can be successfully prepared.

Description

Technical Field

[0001] This invention relates to the field of ink preparation technology, specifically to a high-temperature resistant, colorfast polyarylene ether nitrile modified ink and its preparation method. Background Technology

[0002] The automotive engine compartment is constantly exposed to high temperatures of 150~200℃, corrosion from engine oil / coolant droplets, and humid heat cycles (alternating between -40℃ and 200℃). Ordinary inks are prone to problems under these conditions, and these problems almost always occur simultaneously. For example, yellowing due to high-temperature thermo-oxidative aging; darkening of the coating and blurring of lettering due to resin thermal degradation; and discoloration and peeling due to poor oil resistance. Therefore, how to provide an ink that can withstand high temperatures for a long time to adapt to the working environment of the automotive engine compartment is the technical problem that this invention aims to solve. Summary of the Invention

[0003] The purpose of this invention is to provide a high-temperature resistant, colorfast polyarylene ether nitrile modified ink and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A high-temperature resistant, colorfast modified polyarylene ether nitrile ink, wherein the ink comprises, by weight percentage:

[0006] The film-forming resin system comprises 30-55% polyarylene ether nitrile resin; 3-10% epoxy resin; 20-40% compound solvent; 5-15% high-temperature resistant inorganic pigment; 0.5-3% antioxidant synergistic system; 0.5-3% surface-modified nano-inorganic barrier material; 1-5% hydrolyzable silane-coupled organic-inorganic hybrid precursor; 1-5% curing agent; and 0.1-2% dispersant and rheology modifier. The film-forming resin system includes polyarylene ether nitrile resin, epoxy resin, and auxiliary resins. The inorganic pigments are selected from carbon black, iron oxide red, titanium dioxide, and chrome iron black; the antioxidant synergistic system includes hindered phenolic antioxidants and phosphite-based auxiliary antioxidants; the surface-modified nano-inorganic barrier material is nano-SiO2 modified with a silane coupling agent, with an average particle size of 10-80 nm; the hydrolyzable silane-coupled organic-inorganic hybrid precursor can form a three-dimensional Si-O-Si inorganic network during the curing stage; after curing, an interpenetrating structure of organic cross-linked network and inorganic silicon-oxygen network is formed.

[0007] As a further aspect of the present invention: the polyarylene ether nitrile resin is an epoxy-terminated polyarylene ether nitrile.

[0008] As a further aspect of the present invention: the epoxy resin is a bisphenol A type epoxy resin with an epoxy value of 0.48~0.54 eq / 100g.

[0009] As a further aspect of the present invention: the auxiliary resin is a soluble polyimide precursor, which undergoes an imidization reaction during the curing process to form polyimide.

[0010] As a further aspect of the present invention: the compound solvent includes NMP and xylene, and the mass ratio of NMP to xylene is 2:1.

[0011] As a further aspect of the present invention: the curing agent is dicyandiamide, and the curing temperature is 160~200℃.

[0012] As a further aspect of the present invention, the high-temperature resistant inorganic pigment is selected from carbon black, iron oxide red, titanium oxide and chrome iron black.

[0013] As a further aspect of the present invention: the content of hindered phenolic antioxidants in the antioxidant synergistic system is 0.3~1.5%; the content of phosphite antioxidants is 0.2~1.5%; and the mass ratio of the two is 1:0.5~1:2.

[0014] As a further aspect of the present invention: the amount of the nano-inorganic barrier material added is 1~3%, and it is uniformly dispersed so that the particle size of the pigment aggregate does not exceed 5μm.

[0015] As a further aspect of the present invention: the hydrolyzable silane coupling type organic-inorganic hybrid precursor is an epoxy silane, which undergoes hydrolysis and condensation during the curing stage to form an inorganic silicon-oxygen network.

[0016] The present invention also provides a method for preparing a high-temperature resistant, colorfast, polyarylene ether nitrile modified ink, characterized in that the preparation method includes:

[0017] The dried polyarylene ether nitrile, epoxy resin and auxiliary resin were added to a compound solvent and dissolved to obtain a homogeneous resin solution.

[0018] An antioxidant synergistic system, a dispersant, and an antifoaming agent are added sequentially to the resin solution for dispersion.

[0019] Pre-dispersed high-temperature resistant inorganic pigments were added after pretreatment.

[0020] The obtained slurry was ground in a horizontal sand mill until the pigment particle size did not exceed 5μm;

[0021] Surface-modified nano-inorganic barrier material and hydrolyzable silane-coupled organic-inorganic hybrid precursor hydrolyzable silane precursor are added to the ground slurry;

[0022] Finally, add the curing agent and adjust the viscosity to 1000~1500mPa·s to obtain the finished ink.

[0023] Among them, the polyarylene ether nitrile is dried at 120℃ for more than 2 hours, and the nano-inorganic barrier material is pretreated with silane coupling agent. The curing conditions are: pre-curing at 80℃ for 20~40 minutes and final curing at 160~200℃ for 1~3 hours.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses polyarylene ether nitrile as the main resin, optimizes the adhesion through epoxy modification, and combines it with high-temperature resistant inorganic pigments and anti-yellowing additives. By controlling the moisture, dispersion uniformity and curing parameters throughout the process, a high-temperature resistant and non-coloring ink for automotive engine compartments can be successfully prepared. Detailed Implementation

[0025] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products unless otherwise specified.

[0027] Example 1:

[0028] In this embodiment of the invention, a high-temperature resistant and colorfast polyarylene ether nitrile modified ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0029] 38g of end-capped modified polyarylene ether nitrile (PEN), number average molecular weight 20000, Tg≥180℃, Td5%≥400℃, epoxy end-capped (capping rate≥95%), powder (100 mesh); it serves as the main film-forming resin for inks, and end-capping reduces the thermal decomposition rate, providing a core of high-temperature resistance and anti-yellowing properties;

[0030] 6g E-51 epoxy resin, epoxy value 0.54eq / 100g, viscosity (25℃) 15000mPa·s, low yellowing type;

[0031] 32g NMP / xylene (compound), NMP purity ≥99%, xylene (benzene-free type) purity ≥99%, mass ratio 2:1; used to dissolve resin, adjust ink viscosity, suitable for screen printing;

[0032] 8g carbon black;

[0033] 0.8g antioxidant 1010;

[0034] 0.7g phosphite 168;

[0035] 1.2g dispersant (BYK-110); This belongs to the polycarboxylate class, with a solid content of 50% and a viscosity (25℃) of 1000mPa·s, and is used to improve the dispersibility of carbon black and prevent agglomeration and migration;

[0036] 2.2g dicyandiamide (DICY); This is a curing agent that reacts with E-51 to promote cross-linking and curing.

[0037] 0.3g of defoamer (BYK-055), which belongs to the organosilicon family, has a solid content of 100% and a viscosity (25℃) of 200mPa·s. It is used to eliminate bubbles in the preparation and printing process.

[0038] The remaining solvent (NMP / xylene = 2:1) is used to balance the total mass of the ink to 100g.

[0039] Preparation method:

[0040] Pre-preparation of end-capped modified polyarylene ether nitrile (PEN) is as follows:

[0041] 1. Weigh 38g of uncapped PEN (hydroxyl-terminated type), place it in a 500mL beaker, add 20g of NMP solvent, stir in a 60℃ constant temperature water bath, and sonicate for 20min to completely dissolve the PEN and obtain a PEN solution.

[0042] 2. Add 0.5g of E-51 epoxy resin (small amount, only for end capping) to the PEN solution, adjust the temperature to 80℃, and stir for 1.5h to allow the terminal hydroxyl groups of PEN to react with the epoxy groups and block the active end groups.

[0043] 3. After the reaction is complete, the solution is poured into anhydrous ethanol, the solid precipitates, filtered, and dried at 120℃ for 2 hours to obtain end-capped modified polyarylene ether nitrile (PEN) powder (capping rate ≥95%, which can be verified by FT-IR: the terminal hydroxyl peak is weakened or disappears).

[0044] After the end-capped modified polyarylene ether nitrile (PEN) is prepared, ink preparation is carried out, including:

[0045] Step 1: Place 38g of end-capped modified polyarylene ether nitrile (PEN) and 6g of E-51 epoxy resin into a beaker, add 32g of compound solvent, sonicate for 20min (200W), stir in a 60℃ water bath for 10min, and cool to room temperature to obtain a transparent and uniform resin solution.

[0046] Step 2: Add 0.8g antioxidant 1010, 0.7g phosphite 168, 1.2g dispersant, and 0.3g defoamer to the resin solution. Disperse for 15 minutes at 1500r / min using a high-speed disperser to ensure that the additives are completely dissolved and there are no bubbles.

[0047] Step 3: Add 8g of pretreated carbon black, disperse in a high-speed disperser at 2000r / min for 30min, then pour into a sand mill and mill at 1800r / min for 60min. Filter to remove zirconium beads and obtain pigment dispersion (pigment aggregate particle size not exceeding 5μm).

[0048] Step 4: Add 2.2g of dicyandiamide, disperse for 10min at 1200r / min using a high-speed disperser, adjust the viscosity to 1500mPa·s (25℃) with the remaining solvent, let stand for 5min to remove bubbles, and obtain the finished ink.

[0049] Step 5: Printing and curing: Print on ABS substrate (cleaned and dried) with a 300-mesh screen printing machine to a thickness of 20μm; pre-cur at 80℃ for 30min, then cure at 180℃ for 2h, and allow to cool naturally to room temperature to obtain the ink coating.

[0050] Step 1 is the resin solution preparation stage, Step 2 is the additive mixing stage, Step 3 is the pigment dispersion stage, Step 4 is the ink formulation stage, and Step 5 is the curing stage.

[0051] The core of the above solution is to perform epoxy end-capping treatment on PEN. By reacting the terminal hydroxyl groups with a small amount of epoxy, the active end groups of the PEN molecular chain are blocked, thereby reducing the thermal decomposition rate at high temperatures at the molecular level and solving the problems of easy chain breakage and yellowing of uncapped PEN at high temperatures.

[0052] Example 2:

[0053] In this embodiment of the invention, a high-temperature resistant and colorfast polyarylene ether nitrile modified ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0054] 32g of end-capped modified polyarylene ether nitrile (PEN), number average molecular weight 20000, Tg≥180℃, Td5%≥400℃, epoxy end-capped (capping rate≥95%), powder (100 mesh); it serves as the main film-forming resin for inks, and end-capping reduces the thermal decomposition rate, providing a core of high-temperature resistance and anti-yellowing properties;

[0055] 8g of soluble PI precursor (PAA), number average molecular weight 10000, solid content 100%, soluble in NMP, imidization temperature 180℃; used to form a dual skeleton with PEN to improve ink Tg and high temperature resistance.

[0056] 6g E-51 epoxy resin, epoxy value 0.54eq / 100g, viscosity (25℃) 15000mPa·s, low yellowing type;

[0057] 30g of compound solvent (NMP / xylene), NMP purity ≥99%, xylene (benzene-free type) purity ≥99%, mass ratio 2:1; used to dissolve PEN, PAA and E-51, and adjust viscosity;

[0058] 8g carbon black;

[0059] 0.8g antioxidant 1010;

[0060] 0.7g phosphite 168;

[0061] 1.2g dispersant (BYK-110); This belongs to the polycarboxylate class, with a solid content of 50% and a viscosity (25℃) of 1000mPa·s, and is used to improve the dispersibility of carbon black and prevent agglomeration and migration;

[0062] 2.2g dicyandiamide (DICY); This is a curing agent that reacts with E-51 to promote cross-linking and curing.

[0063] 0.3g of defoamer (BYK-055), which belongs to the organosilicon family, has a solid content of 100% and a viscosity (25℃) of 200mPa·s. It is used to eliminate bubbles in the preparation and printing process.

[0064] The remaining solvent (NMP / xylene = 2:1) is used to balance the total mass of the ink to 100g.

[0065] Preparation method:

[0066] Unlike Example 1, the resin solution preparation (step 1) and curing stage (step 5) are different:

[0067] Resin solution preparation: 32g of end-capped modified polyarylene ether nitrile (PEN), 8g of PI precursor (PAA), and 6g of E-51 epoxy resin were placed in a beaker, 30g of compound solvent was added, and the mixture was sonicated for 25min (200W), stirred in a constant temperature water bath at 70℃ for 15min, and cooled to room temperature to obtain a transparent and uniform resin solution (ensuring that PAA is completely dissolved and there is no precipitation).

[0068] Curing stage: After printing, pre-cur at 80℃ for 30 minutes (to remove solvent), then raise the temperature to 180℃ and keep it at a constant temperature for 2 hours. During this process, the imidization reaction of PAA (PAA to PI) is completed simultaneously, and finally a PEN / PI dual heat-resistant skeleton is formed (which can be verified by FT-IR: imide characteristic peaks appear).

[0069] Example 2, based on the end-capped modified polyarylene ether nitrile (PEN) of Example 1, introduces a soluble PI precursor (PAA). Through a 180°C isothermal treatment during the curing stage, the imidization reaction of PAA is completed simultaneously, forming a PEN / PI dual high Tg heat-resistant skeleton, achieving "dual skeleton synergistic reinforcement". Compared with Example 1, the thermal degradation rate is significantly reduced, the anti-yellowing performance is further optimized, and the problem of insufficient high temperature resistance of a single PEN skeleton is solved.

[0070] Example 3:

[0071] In this embodiment of the invention, a high-temperature resistant and colorfast polyarylene ether nitrile modified ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0072] 95g of the finished ink prepared in Example 2;

[0073] 2g of surface-modified nano-SiO2, with a particle size of 50nm, modified with silane coupling agent (KH-550);

[0074] 3g of silane coupling agent KH-550 (unreacted portion) is used to improve the compatibility between nano-SiO2 and the resin system and prevent agglomeration.

[0075] Preparation method:

[0076] Unlike Example 2, a nano-SiO2 pretreatment and pigment dispersion stage (step 3) was added, specifically:

[0077] 1. Pretreatment of nano-SiO2 (core step): Weigh 3g of nano-SiO2 and 2g of silane coupling agent KH-550, put them into a 50mL beaker, add 5g of NMP solvent, sonicate for 15min (200W), stir in an 80℃ water bath for 30min to make the coupling agent uniformly coat the surface of nano-SiO2, cool to room temperature to obtain a surface-modified nano-SiO2 dispersion (without obvious agglomeration).

[0078] 2. Pigment dispersion stage (modified pigment dispersion steps of Example 2): Add the above modified nano-SiO2 dispersion to the pigment dispersion liquid (carbon black + resin solution + additives) of Example 2, disperse for 40 min at 2200 r / min in a high-speed disperser, then pour into a sand mill and mill at 1800 r / min for 90 min, filter to remove zirconium beads, and ensure that the nano-SiO2 particle size is 3 μm.

[0079] Example 3, based on the PEN / PI dual-skeleton system of Example 2, introduces surface-modified nano-SiO2. Compatibility is improved through a silane coupling agent. High-speed dispersion and extended milling time ensure uniform dispersion of nano-SiO2 within the ink system, creating a microscopic oxygen diffusion "maze effect." Compared to Example 2, this method introduces a barrier layer at the microstructural level, extending the oxygen diffusion path, reducing the oxidation rate, further optimizing anti-yellowing performance, and improving thermal stability. This solves the problems of easy oxygen penetration and yellowing with long-term aging in the dual-skeleton system.

[0080] Example 4:

[0081] In this embodiment of the invention, a high-temperature resistant and colorfast polyarylene ether nitrile modified ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0082] 92g of the finished ink prepared in Example 3;

[0083] 4g of GPTMS silane (3-glycidyl etheroxypropyltrimethoxysilane) is used to form an inorganic silicon-oxygen network, which forms an IPN structure with the organic network.

[0084] 0.5g deionized water; promotes the hydrolysis of GPTMS silanes;

[0085] 0.5g catalyst (dibutyltin dilaurate); accelerates GPTMS hydrolysis and Si–O–Si polycondensation reaction;

[0086] The remaining solvent (NMP / xylene = 2:1) is used to balance the total mass of the ink to 100g.

[0087] Preparation method:

[0088] Ink preparation stage (step 4): Add 4g GPTMS silane, 0.5g deionized water and 0.5g catalyst to the pigment dispersion (containing nano SiO2) in Example 3. Disperse at 1500r / min in a high-speed disperser for 20min to ensure uniform mixing of all components. Then adjust the viscosity to 1500mPa·s (25℃) with the remaining solvent and let stand for 5min to remove air bubbles.

[0089] Curing stage (step 5): After printing, pre-cur at 80℃ for 30 minutes (to remove solvent), then raise the temperature to 180℃ and keep it at a constant temperature for 2.5 hours;

[0090] Three reactions occur simultaneously during the fixation process: the epoxy crosslinking reaction of E-51 with dicyandiamide; the hydrolysis reaction of GPTMS silane; and the Si–O–Si condensation reaction of the hydrolysis products, ultimately forming an in-situ interpenetrating network (IPN) of “organic crosslinking network (PEN / PI / epoxy) + inorganic silicon-oxygen network” (which can be verified by FT-IR: the Si–O–Si characteristic peak appears).

[0091] Based on the dual-skeleton + nano barrier in Example 3, GPTMS silane was introduced. Through in-situ reactions during the curing stage (epoxy crosslinking, silane hydrolysis, Si–O–Si polycondensation), an organic-inorganic interpenetrating network (IPN) was formed, achieving "network-level innovation". Compared with Example 3, the IPN structure allows the organic and inorganic networks to interpenetrate and work synergistically, which not only further reduces the oxygen diffusion rate, but also improves the hardness, oil resistance and long-term thermal aging stability of the coating. It solves the problems of loose network structure and insufficient oil resistance of the nano barrier system, and further optimizes the anti-yellowing performance.

[0092] Example 5:

[0093] In this embodiment of the invention, a high-temperature resistant and colorfast polyarylene ether nitrile modified ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0094] 40g covalent antioxidant copolymer polyarylene ether nitrile (PEN); number average molecular weight 22000, Tg≥190℃, Td5%≥420℃, main chain contains covalently linked hindered phenolic antioxidant units (content 8%).

[0095] 6g PI (polyimide); soluble PI, consistent with the PAA imidized product of Example 2; forms a dual framework with covalent antioxidant copolymer polyarylene ether nitrile (PEN) to improve high temperature resistance;

[0096] 6g E-51 epoxy resin; crosslinking agent, used to improve adhesion and crosslinking density;

[0097] 28g of compound solvent (NMP / xylene = 2:1) is used to dissolve each resin component and adjust the viscosity;

[0098] 8g carbon black;

[0099] 3g nano-SiO2;

[0100] 3g GPTMS silane;

[0101] 2g dicyandiamide (DICY);

[0102] 4g of additives, including dispersant, defoamer and catalyst, namely dispersant BYK-110 (1.5g), defoamer BYK-055 (0.5g), catalyst dibutyltin dilaurate (0.5g) and coupling agent KH-550 (1.5g).

[0103] Preparation method:

[0104] The covalent antioxidant copolymer polyarylene ether nitrile (PEN) was prepared in advance, specifically as follows:

[0105] 1. Weigh 40g of PEN comonomer (containing diphenol and dihalobenzonitrile), add 0.5g of comonomer containing hindered phenol structure (4,4'-dihydroxy-α-methylstyrene), put it into a reaction vessel, add 50g of NMP solvent, purge with nitrogen for protection, heat to 180℃, and react for 4h to copolymerize the hindered phenol monomer with the PEN monomer.

[0106] 2. After the reaction is complete, the reaction solution is poured into anhydrous ethanol, a solid is precipitated, filtered, and dried at 120℃ for 3 hours to obtain covalent antioxidant copolymer polyarylene ether nitrile (PEN) powder (the main chain contains covalent antioxidant units, which can be verified by FT-IR: the characteristic peak of hindered phenol appears).

[0107] The ink preparation process differs from that in Example 4 in the following ways:

[0108] 1. Resin solution preparation (alternative to the resin solution steps in Example 4): Place 40g of covalent antioxidant copolymer polyarylene ether nitrile (PEN), 6g of PI, and 6g of E-51 epoxy resin into a beaker, add 28g of compound solvent, sonicate for 30min (200W), stir in a 75℃ constant temperature water bath for 20min, and cool to room temperature to obtain a transparent and uniform resin solution (ensure that all resins are completely dissolved).

[0109] 2. Ink preparation stage (modified ink preparation steps of Example 4): Add 4g of additives (dispersant, defoamer, catalyst, coupling agent), 8g of carbon black, 3g of surface-modified nano-SiO2, and 3g of GPTMS silane in sequence. Disperse in a high-speed disperser at 2200r / min for 40min. Then pour into a sand mill and sand mill at 1800r / min for 90min. Filter to remove zirconium beads. Add 2g of dicyandiamide and disperse in a high-speed disperser at 1200r / min for 10min. Let stand for 5min to remove bubbles.

[0110] 3. Curing Step (Curing Step of Optimized Example 4): After printing, pre-cur at 80℃ for 30 min, and then constant temperature curing at 185℃ for 2.5 h to ensure that the epoxy crosslinking, silane hydrolysis and polycondensation, and PI imidization (if PAA is used, they need to be completed simultaneously) reactions are complete, forming a composite system of "covalent antioxidant PEN / PI dual skeleton + nano barrier + IPN hybrid network".

[0111] Based on the IPN hybrid network of Example 4, the antioxidant groups were changed from "additive type" to "covalently linked type". A comonomer containing hindered phenolic structure was introduced in the PEN synthesis stage, so that the antioxidant units were covalently bonded to the PEN main chain to form a self-stabilizing PEN resin. Compared with Example 4, the antioxidant groups do not migrate or volatilize, and can stably capture free radicals generated by thermo-oxidative aging for a long time. This achieves a leap in anti-yellowing performance from a mechanistic perspective, solving the problem of easy migration and antioxidant effect decay of the additive antioxidants in the previous examples under long-term high temperature. At the same time, it integrates the advantages of dual framework, nano barrier and IPN network.

[0112] Comparative Example 1:

[0113] In this embodiment of the invention, an epoxy-based high-temperature resistant ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0114] E-51 epoxy resin: 45g;

[0115] Polyamide curing agent: 5g;

[0116] Xylene / cyclohexanone mixed solvent: 35g;

[0117] Common carbon black pigment: 10g;

[0118] Dispersant, leveling agent, defoamer: 5g;

[0119] Preparation method:

[0120] 1. Add epoxy resin to the solvent and stir to dissolve.

[0121] 2. Add pigments and additives, disperse at high speed, and mill.

[0122] 3. Add curing agent and stir evenly to obtain ink.

[0123] 4. Curing at 120℃ for 30 minutes after printing.

[0124] Comparative Example 2:

[0125] In this embodiment of the invention, a polyester-based high-temperature resistant ink and its preparation method are provided. The ink, by weight (based on 100g, accurately weighable), comprises:

[0126] Saturated polyester resin: 40g;

[0127] Amino resin curing agent: 6g;

[0128] Ethylene glycol monobutyl ether solvent: 36g;

[0129] High-temperature resistant carbon black: 12g;

[0130] Dispersant and anti-yellowing agent: 6g.

[0131] Preparation method:

[0132] 1. Polyester resin is mixed and dissolved with solvent;

[0133] 2. Add pigments and additives, disperse and grind;

[0134] 3. Add amino resin and stir to obtain ink;

[0135] 4. Curing temperature: 150℃ for 30 minutes.

[0136] Comparative Example 3:

[0137] In this embodiment of the invention, an unmodified pure polyarylether ether nitrile (PEN) ink and its preparation method are provided. The ink, by mass (based on 100g, accurately weighable), comprises:

[0138] Uncapped, unmodified ordinary PEN resin: 40g;

[0139] E-51 epoxy resin: 5g;

[0140] NMP / xylene solvent: 37g;

[0141] Carbon black: 10g;

[0142] Common dispersant and defoamer: 8g.

[0143] Preparation method:

[0144] 1. PEN resin and epoxy resin are soluble in solvents.

[0145] 2. Add pigments and additives, disperse, and grind.

[0146] 3. Curing temperature: 180℃ for 2 hours after printing.

[0147] Testing process:

[0148] 1. Sample preparation:

[0149] Five groups of inks were prepared according to the formulations of the five examples;

[0150] A commonly used substrate for automotive engine compartments (ABS board) was selected, cleaned and dried with anhydrous ethanol, and three parallel samples were printed for each set of examples (a total of 15 samples). The printed pattern was standard letters / scales (simulating electronic tags and wire harness markings). Curing was completed according to the curing parameters of each example and cooled to room temperature. In subsequent experiments, each experiment corresponded to 15 samples, and the test results were taken as the average value.

[0151] 2. High-temperature thermo-oxidative aging test (200℃, 72h):

[0152] Place the cured ink sample in a constant temperature forced-air drying oven;

[0153] Set the temperature to 200℃ and maintain it for 72 hours.

[0154] Remove the sample and allow it to cool to room temperature;

[0155] The color difference value ΔE before and after aging was measured using a colorimeter.

[0156] 3. Engine oil resistance test (100℃, 24h):

[0157] The ink sample was completely immersed in 100°C automotive engine oil and kept there for 24 hours.

[0158] Remove the sample, wipe it clean with anhydrous ethanol, and let it stand at room temperature for 2 hours.

[0159] The adhesion rating was tested using the cross-cut test method.

[0160] 4. Damp heat cycle test:

[0161] Set the loop condition:

[0162] -40℃ constant temperature for 2 hours (simulating low temperature start-up conditions);

[0163] Heat the coating to 25°C at a constant rate and maintain the temperature for 1 hour (temperature transition to avoid cracking of the coating due to sudden cooling and heating).

[0164] The temperature was raised to 200℃ at a constant rate and maintained for 2 hours (simulating the high-temperature working conditions of the engine).

[0165] Cool down to 25℃ at a uniform rate and maintain the temperature for 1 hour;

[0166] Repeat the above cycle 10 times in total;

[0167] After the cycle is complete, remove the sample and cool it to room temperature;

[0168] Observe the appearance of the coating (whether it is cracked, peeling, or yellowed), test the adhesion using the cross-cut test, and test the color difference ΔE using a colorimeter.

[0169] 5. Thermogravimetric analysis:

[0170] Take a small amount of the ink-cured film and perform a thermogravimetric test under a nitrogen atmosphere;

[0171] Heating rate: 10℃ / min; Test range: room temperature ~ 600℃.

[0172] Record the 5% thermogravimetric temperature Td5.

[0173] 6. Data Processing: Summarize all test data, compare the performance differences of the five embodiments, and verify the progressive effect of each embodiment; the evaluation is based on commonly used national standard methods: color difference: refer to GB / T11186.2-1989 (measured by colorimeter); adhesion: GB / T9286-1998 cross-cut test; thermogravimetric analysis: refer to GB / T27761-2011.

[0174] Test data:

[0175] The data from the high-temperature thermo-oxidative aging test (200℃, 72h) are shown in the table below:

[0176] Table 1

[0177] Group ΔE (mean) Comparative Example 1 (Epoxy) 5.8 Comparative Example 2 (Polyester) 4.9 Comparative Example 3 (Unmodified PEN) 3.6 Example 1 2.7 Example 2 2.0 Example 3 1.5 Example 4 1.1 Example 5 0.8

[0178] The data from the engine oil resistance test (100℃, 24h) are shown in the table below:

[0179] Table 2

[0180] Group Adhesion rating Comparative Example 1 2B Comparative Example 2 3B Comparative Example 3 3B Example 1 4B Example 2 4B Example 3 4B Example 4 5B Example 5 5B

[0181] The damp heat cycling test data are shown in the table below:

[0182] Table 3

[0183] Group Appearance ΔE Adhesion Comparative Example 1 Cracks, slight peeling 6.2 2B Comparative Example 2 Local cracking 5.1 3B Comparative Example 3 Slightly dark 3.8 3B Example 1 No cracks 2.9 4B Example 2 No cracks 2.2 4B Example 3 No cracks 1.7 4B Example 4 No cracks 1.3 5B Example 5 No defects 0.9 5B

[0184] Thermogravimetric analysis (nitrogen atmosphere) data are shown in the table below:

[0185] Table 4

[0186] Group Td5% (°C) Comparative Example 1 312 Comparative Example 2 328 Comparative Example 3 398 Example 1 408 Example 2 425 Example 3 438 Example 4 452 Example 5 468

[0187] Data Analysis:

[0188] Example 1 reduces the content of active hydroxyl groups at the ends of the molecular chain by end-capping treatment on the unmodified PEN system, inhibiting free radical generation and chain segment breakage reactions in the early stage of thermo-oxidative aging at the molecular level. Therefore, under the condition of 200℃×72h, ΔE decreased from 3.6 in Comparative Example 3 to 2.7, while Td5% increased from 398℃ to 408℃, indicating that end-capping stabilization effectively delayed the thermal decomposition initiation temperature. After soaking in engine oil, the adhesion reached 4B, which is significantly improved compared to 3B of unmodified PEN, indicating that the cross-linking reaction was more complete and the interfacial bonding was enhanced. No cracking occurred during wet heat cycling and the color difference was controlled at 2.9, proving that end-capping stabilization has a fundamental improvement effect on inhibiting thermo-oxidative-moisture synergistic aging. However, since the system is still a single organic network structure, the oxygen diffusion barrier ability is limited, and the performance improvement is only at the first-gradient level. The cost increase is small, mainly due to the addition of end-capping steps and a small amount of reactants. It is suitable for scenarios with moderate temperature resistance requirements and cost sensitivity.

[0189] Example 2 introduces a soluble PI precursor to form a PEN / PI dual high Tg framework structure based on Example 1. The rigid structure of the imide ring significantly increases the energy required for chain segment movement, thereby suppressing molecular thermal vibration and oxygen diffusion rate at high temperatures. As a result, ΔE is further reduced to 2.0, and Td5% is increased to 425℃, showing a significant leap in thermal stability. The adhesion remains at 4B, but ΔE drops to 2.2 after wet heat cycling, which is better than Example 1, indicating that the dual framework structure is more stable in terms of thermal cycling stress release. The mechanism is that the aromatic imide structure increases the glass transition temperature and forms a denser inter-chain stacking structure. However, the cost of PI raw materials is higher and the processing temperature control requirements are more stringent. Therefore, a second gradient improvement is formed between performance and cost, which is suitable for engine area markings with higher temperature resistance requirements.

[0190] Example 3 incorporates surface-modified nano-SiO2 into a dual-skeleton structure, forming a microscopic "maze effect" oxygen diffusion barrier structure. This significantly extends the diffusion path of oxygen molecules in the coating and reduces the oxygen permeation rate. Consequently, the thermo-oxidative aging ΔE further decreases to 1.5, while Td5% increases to 438℃. Simultaneously, after wet heat cycling, ΔE is only 1.7, and the adhesion remains stable at 4B. This indicates that the nanofiller not only improves thermal stability but also enhances the coating's density and oil penetration resistance. This improvement stems from a physical barrier mechanism rather than simply enhanced chemical stability, representing structural-level reinforcement. From a cost perspective, the amount of nano-SiO2 used is relatively low (typically ≤3%), making it more economical than PI. While the process involves an additional dispersion step, it can be scaled up industrially. Therefore, while significantly improving performance, the cost increase remains controllable, making it a crucial stage for a marked improvement in the performance / cost ratio.

[0191] Example 4 further introduces a silane coupling agent to form an organic-inorganic in-situ IPN interpenetrating network structure. Through the synergistic crosslinking of the epoxy-cured network and the Si–O–Si inorganic condensation network, the system forms a dual-network interlocking structure, which significantly improves the crosslinking density and interfacial bonding strength. As a result, the thermo-oxidative aging ΔE decreases to 1.1, and after wet-heat cycling, it is only 1.3 with an adhesion of 5B. The Td5% increases to 452℃, indicating that the inorganic network makes a significant contribution to the stability and structural maintenance of the high-temperature carbon layer. The IPN structure can also significantly inhibit oil penetration and swelling, thus explaining the leap in adhesion level. However, this system requires additional silane, catalyst, and humidity control conditions, increasing the process complexity and raising material and production management costs. It is suitable for high-end engines or long-term high-temperature exposure environments, but its economic efficiency is slightly lower than that of Example 3.

[0192] Example 5 introduces covalently bound hindered phenolic antioxidant units into the PEN main chain, achieving structural embedding of antioxidant groups. This avoids the migration or volatilization problems of traditional antioxidants, ensuring the long-term stability of the free radical capture mechanism. As a result, ΔE is reduced to 0.8, Td5% reaches 468℃, and after wet heat cycling, ΔE is only 0.9 with stable adhesion of 5B. This indicates that it achieves self-stabilizing thermo-oxidative protection at the mechanistic level, making it the best solution in terms of thermal stability and color retention among the five examples. This improvement comes from a fundamental chemical change, where the antioxidant structure participates in the main chain construction rather than being physically added. However, this requires customized comonomers, repolymerization reactions, and more complex quality control, resulting in the highest R&D and production costs and the greatest industrialization threshold.

[0193] In summary: if extreme heat resistance and long-term stability are the primary objectives, Example 5 has the best performance; if the goal is to balance comprehensive performance, processing feasibility and cost, Example 3 shows a significant cost-performance advantage and is the optimal example for engineering applications; Example 4 is suitable for high-end application scenarios, while Examples 1 and 2 correspond to low-to-medium performance requirements, respectively.

[0194] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature resistant, colorfast modified polyarylene ether nitrile ink, characterized in that, The ink comprises, by weight percentage: The composition includes: 30-55% film-forming resin system; 3-10% epoxy resin; 20-40% compound solvent; 5-15% inorganic pigment; 0.5-3% antioxidant synergistic system; 0.5-3% surface-modified nano-inorganic barrier material; 1-5% hydrolyzable silane-coupled organic-inorganic hybrid precursor; 1-5% curing agent; 0.1-2% dispersant and rheology modifier; wherein the film-forming resin system includes polyarylene ether nitrile resin, epoxy resin and auxiliary resin; the inorganic pigment is selected from carbon black, iron oxide red, titanium oxide and chrome iron black; the antioxidant synergistic system includes hindered phenolic antioxidants and phosphite auxiliary antioxidants; the surface-modified nano-inorganic barrier material... The surface-modified nano-inorganic barrier material is nano-SiO2 modified with a silane coupling agent, with an average particle size of 10-80 nm. The hydrolyzable silane-coupled organic-inorganic hybrid precursor can form a three-dimensional Si-O-Si inorganic network during the curing stage. After curing, an interpenetrating structure of organic cross-linked network and inorganic silicon-oxygen network is formed. The auxiliary resin is a soluble polyimide precursor, which undergoes an imidization reaction during curing to form polyimide. In the antioxidant synergistic system, the content of hindered phenolic antioxidant is 0.3-1.5%; the content of phosphite antioxidant is 0.2-1.5%; and the mass ratio of the two is 1:0.5-1:

2.

2. The high-temperature resistant, colorfast polyarylene ether nitrile modified ink according to claim 1, characterized in that, The polyarylene ether nitrile resin is an epoxy-terminated polyarylene ether nitrile.

3. The high-temperature resistant, colorfast polyarylene ether nitrile modified ink according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin with an epoxy value of 0.48~0.54 eq / 100g.

4. The high-temperature resistant, colorfast polyarylene ether nitrile modified ink according to claim 1, characterized in that, The compound solvent includes NMP and xylene, with a mass ratio of NMP to xylene of 2:

1.

5. The high-temperature resistant, colorfast polyarylene ether nitrile modified ink according to claim 1, characterized in that, The curing agent is dicyandiamide, and the curing temperature is 160~200℃.

6. The high-temperature resistant, colorfast polyarylene ether nitrile modified ink according to claim 5, characterized in that, The amount of the nano-inorganic barrier material added is 1~3%, and it is uniformly dispersed so that the particle size of the pigment aggregate does not exceed 5μm.

7. The high-temperature resistant, colorfast polyarylene ether nitrile modified ink according to claim 1, characterized in that, The hydrolyzable silane-coupled organic-inorganic hybrid precursor is an epoxy silane, which undergoes hydrolysis and condensation during the curing stage to form an inorganic silicon-oxygen network.

8. The method for preparing high-temperature resistant and colorfast polyarylene ether nitrile modified ink according to any one of claims 1 to 7, characterized in that, The preparation method includes: The dried polyarylene ether nitrile, epoxy resin and auxiliary resin were dissolved in a compound solvent to obtain a homogeneous resin solution. An antioxidant synergistic system, a dispersant, and an antifoaming agent are added sequentially to the resin solution for dispersion. Pre-dispersed by adding pre-treated inorganic pigments; The obtained slurry was ground in a horizontal sand mill until the pigment particle size did not exceed 5μm; Surface-modified nano-inorganic barrier materials and hydrolyzable silane-coupled organic-inorganic hybrid precursors were added to the ground slurry. Finally, add the curing agent and adjust the viscosity to 1000~1500 mPa·s to obtain the finished ink; Among them, the polyarylene ether nitrile is dried at 120℃ for more than 2 hours, and the nano-inorganic barrier material is pretreated with silane coupling agent. The curing conditions are: pre-curing at 80℃ for 20~40 minutes and final curing at 160~200℃ for 1~3 hours.