Carbon fiber carbonization protective ink and preparation method thereof

Abstract

The application discloses a carbon fiber carbonization protective ink and a preparation method thereof, and relates to the technical field of novel inks. The carbon fiber carbonization protective ink is prepared from raw materials containing the following components in parts by mass: 20-40 parts of epoxy-modified silicone resin, 10-30 parts of high-temperature-resistant filler, 30-50 parts of solvent, 1-5 parts of additive, and 1.5-3 parts of weather-resistant agent. The epoxy value and solid content of the epoxy-modified silicone resin are optimized, the particle size of the high-temperature-resistant filler is controlled, and a low-volatility solvent system is adopted, so that the problems of ink easy settlement and caking in the prior art are solved. In combination with the compounding effect of specific additives and a high-shear dispersion process, the uniformity and viscosity stability of the ink are significantly enhanced, and the settlement phenomenon in long-term storage is avoided.

Description

Technical Field

[0001] This invention relates to the field of novel ink technology, specifically to a carbon fiber carbonization protective ink and its preparation method. Background Technology

[0002] In the carbon fiber production process, pre-oxidized fibers undergo a violent pyrolysis reaction during the intermediate-temperature carbonization stage to form a disordered graphite structure. During this stage, the fiber surface is prone to thermal oxidation etching and molecular chain breakage, leading to severe deterioration of mechanical properties. To isolate oxygen and maintain the integrity of the fiber morphology, the industry commonly employs a protective ink coating technique. This ink must simultaneously meet three core requirements: high-temperature film density (oxygen barrier), long-term storage stability (anti-settling), and weather resistance (resistance to UV / humid heat aging). Currently, most mainstream carbonization protective inks use silicone resin as the matrix. Although they possess certain heat resistance, they still have significant drawbacks: they are prone to settling and clumping during storage, resulting in uneven leveling during coating; and after long-term storage, the applied ink layer is prone to cracking and powdering, losing its protective function for the fiber.

[0003] Existing technologies have attempted to improve the protection by adding dispersants or single weather-resistant components, but these methods have failed to address the issue of synergistic protection against aging through multiple mechanisms, and the results have been generally poor. Therefore, there is an urgent need to develop a carbonization protective ink that combines high storage stability, long-lasting weather resistance, and process applicability to overcome the bottlenecks in continuous carbon fiber production. Summary of the Invention

[0004] To address the problems of existing carbon fiber carbonization protective inks, such as easy sedimentation and clumping during long-term storage and insufficient weather resistance leading to aging and failure of the protective layer, this invention provides a carbon fiber carbonization protective ink that combines high storage stability with long-term weather resistance. By optimizing the epoxy-modified silicone resin matrix, the high-temperature resistant filler dispersion system, and the synergistic effect of functional weather-resistant agents, the ink's storage uniformity, UV aging resistance, and damp heat stability are significantly improved, ensuring efficient protection during the carbonization process.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a carbon fiber carbonization protective ink, which is prepared from raw materials comprising the following parts by weight: 20-40 parts of epoxy modified silicone resin, 10-30 parts of high temperature resistant filler, 30-50 parts of solvent, 1-5 parts of additives, and 1.5-3 parts of weather resistant agent.

[0006] The weather-resistant agent is a compound represented by Formula 1:

[0007] Formula 1: ;

[0008] R1 in Formula 1 is a substituent;

[0009] R1 is selected from: amino, halogen, phenyl, C1-C5 alkyl, C1-C5 alkoxy.

[0010] Furthermore, the epoxy-modified silicone resin has an epoxy value of 0.06-0.16 and a solid content of 50±1%.

[0011] Furthermore, the high-temperature resistant filler is selected from one or more of the following: mica powder, talc powder, kaolin, and silica;

[0012] The particle size D50 of the high-temperature resistant filler is 1-10 μm.

[0013] Furthermore, the solvent is selected from one or more of diethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol phenyl ether, and terpineol.

[0014] Furthermore, the additives are selected from BYK-333, BYK-055 and EFKA-4310, and the mass ratio of the three is (1-2):(0.5-1):(1-2).

[0015] Furthermore, the halogen is selected from chlorine.

[0016] Furthermore, the alkyl groups of C1-C5 are selected from: methyl, ethyl, propyl, isopropyl, and tert-butyl.

[0017] Furthermore, the alkoxy groups of C1-C5 are selected from: methoxy and ethoxy.

[0018] Furthermore, the weather-resistant agent is selected from one or more of the compounds shown in the following structures;

[0019] ;

[0020] ;

[0021] .

[0022] A method for preparing a carbon fiber carbonization protective ink includes the following steps:

[0023] S1: Add 1 / 2 part by mass of the solvent and all the additives into the reactor, and stir at a speed of 300-500 rpm for 5-15 minutes to obtain material A;

[0024] S2: Add high-temperature resistant filler to material A and disperse at 1000-1500 rpm for 20-40 minutes to obtain material B;

[0025] S3: Adjust the rotation speed to 400-600 rpm, but under a nitrogen atmosphere, add the epoxy-modified silicone resin, weathering agent and 1 / 2 part by mass of solvent to the system, stir at 400-600 rpm for 30-60 minutes to obtain material C, filter, and obtain the carbon fiber carbonization protective ink.

[0026] Furthermore, the temperature of the dispersed control material in S2 is below 40°C.

[0027] The mechanism of action of the weather-resistant agent described in this invention relies on the synergistic effect of three core groups in its parent structure: triazine, imino, and pentamethylpiperidine. Triazine, as a large π-conjugated system, can efficiently absorb ultraviolet light (UVB and / or UVA bands) and convert light energy into heat energy through energy level transitions, thereby reducing the direct photochemical damage of ultraviolet light to epoxy-modified silicone resin and fillers in inks. Pentamethylpiperidine, as the core structure of a hindered amine light stabilizer, captures free radicals induced by ultraviolet light through tertiary amine groups, thereby continuously inhibiting photo-oxidative degradation. Imino can react with oxygen free radicals to terminate the oxidation process, while expanding the conjugated system. It enhances the ultraviolet absorption efficiency of triazine by promoting intramolecular electron delocalization and reduces the photoexcited state lifetime. Finally, through a triple synergistic mechanism of ultraviolet shielding, free radical quenching, and intramolecular energy and / or electron transfer, it significantly improves the weather resistance and thermo-oxidative stability of inks under high temperature and ultraviolet irradiation.

[0028] The formulation described in this invention comprises epoxy-modified silicone resin, high-temperature resistant filler, solvent, additives, and weathering agent. Through the selection of component types, optimization of proportions, and synergistic coordination of the preparation process, it effectively solves two major technical problems: insufficient long-term storage stability and weathering defects. Regarding storage stability, the epoxy-modified silicone resin, with its optimized epoxy value (0.06-0.16) and solid content (50±1%), provides moderate viscosity and cohesion, enhancing compatibility with the filler. The high-temperature resistant filler, with its strictly controlled particle size D50 of 1-10 μm, forms a stable network with the resin. The low-volatility solvent maintains the homogeneity of the system. The compounded additives (BYK-333 as a wetting agent, BYK-055 as a dispersant, and EFKA-4310 as an anti-settling agent) jointly prevent filler sedimentation and agglomeration. Combined with high-shear dispersion and nitrogen protection processes, it ensures no long-term sedimentation, clumping, or viscosity changes. In terms of weather resistance, the weathering agent further optimizes thermal stability, light stability, and long-term weather resistance; epoxy-modified silicone resin forms a dense cross-linked structure to resist moisture penetration; high-temperature resistant fillers enhance ultraviolet scattering and mechanical strength; solvents and additives ensure uniform dispersion of the weathering agent and coating integrity, ultimately enabling the carbon fiber carbonization protective ink to be stored for a long time and to withstand ultraviolet and / or damp heat aging, meeting the industrial reliability requirements of the carbon fiber carbonization process for high-performance protective inks.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. Significantly Improved Long-Term Storage Stability: This invention addresses the issues of ink sedimentation and agglomeration in existing technologies by optimizing the epoxy value and solid content of the epoxy-modified silicone resin, controlling the particle size of high-temperature resistant fillers, and employing a low-volatile solvent system. Combined with the effects of specific additives (such as the BYK series) and a high-shear dispersion process, the uniformity and viscosity stability of the ink are significantly enhanced, ensuring no sedimentation during long-term storage.

[0031] 2. Significantly Enhanced Overall Weather Resistance: This invention introduces functional weather-resistant agents (such as compounds containing triazine, imino, and pentamethylpiperidinyl groups), which effectively improve the ink's resistance to UV aging and damp heat stability through a synergistic mechanism of UV shielding, free radical quenching, and intramolecular energy transfer. Compared to single-function weather-resistant agents in existing technologies, this design significantly reduces the risk of degradation of the protective layer in complex environments, such as cracking or decreased adhesion.

[0032] 3. Reliable and Optimized Protective Performance: This invention ensures efficient protection of carbon fibers by optimizing the component ratio and employing a nitrogen protection process. Overall, the mechanical strength and coating integrity of the ink are enhanced, significantly reducing the risk of fiber breakage during pre-oxidation and maintaining fiber fineness stability, thus meeting the stringent reliability requirements of industrial applications. Attached Figure Description

[0033] Figure 1 This is the NMR spectrum of the weathering agent 1 described in this invention. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Preparation Example 1

[0036] Preparation of weathering agent 1:

[0037] ;

[0038] Under nitrogen protection, 15 g of compound A and 8.49 g of compound B were dissolved in 180 mL of a mixed solvent of 1,4-dioxane / diisopropylamine (120 mL / 60 mL). 0.2 g of palladium acetate, 0.63 g of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, and 0.25 g of CuI were added to the system, and the reaction was carried out at 90 °C for 6 h. After the reaction was complete, the mixture was filtered hot using diatomaceous earth to remove salts and catalyst. The reaction solution was concentrated and separated by silica gel column chromatography using a mixed solvent of n-heptane and ethyl acetate as the eluent. The solution was evaporated to dryness to obtain 16.81 g of compound C. The mass spectra of compound C were observed at 794 using M / Z MS+1.

[0039] ;

[0040] Under nitrogen protection, 16.81 g of compound C, 4.88 g of compound D, 11.27 g of potassium phosphate trihydrate, 0.20 g of CuI, 0.08 g of pyridine-2-carboxylic acid, and 200 g of DMSO were added to the reaction mixture, which was then heated at 90 °C for 14 h. After cooling, the reaction mixture was extracted with ammonia solution and methyl tert-butyl ether. The organic phase was washed five times with water and twice with saturated NaCl solution. Finally, the combined organic phases were dried over anhydrous magnesium sulfate, concentrated, and separated by silica gel column chromatography using a mixed solvent of n-heptane and ethyl acetate as the eluent. The mixture was evaporated to dryness to obtain 16.49 g of weathering agent 1. The mass spectrometry of weathering agent 1 was 949, and the analysis was performed using M / Z MS+1.

[0041] NMR of weathering agent 1 1 H NMR (Chloroform-d, Figure 1 ) δ 6.73 (t, 1H), 6.15 (t, 1H),5.22 (p, 1H), 4.45 (d, 2H), 4.17-4.06 (m, 3H), 3.86 (m, 1H), 3.75 (s, 3H),3.66 (s, 3H), 3.54 (t, 4H), 3.40 (m, 1H), 2.27 (d, 6H), 2.14 (dd, 4H), 1.89(dd, 4H), 1.77-1.65 (m, 4H), 1.53 (d, 3H), 1.42-1.33 (m, 4H), 1.31 (dd, 6H),1.24 (dd, 12H), 1.12 (dd, 12H), 0.95 (m, 6H).

[0042] Preparation Examples 2-6

[0043] In Preparation Examples 2-6, weathering agent 2-weathering agent 6 were prepared sequentially, following the preparation method of Preparation Example 1, except that compound D was replaced, and the rest remained the same as in Preparation Example 1. For details, please refer to Table 1.

[0044] Table 1

[0045]

[0046] Example 1

[0047] Preparation of a carbon fiber carbonization protective ink:

[0048] 1. Raw material composition

[0049] Epoxy-modified silicone resin: 30 parts, purchased from Hubei Longsheng Sihai New Material Co., Ltd., product number SH-023-4;

[0050] High-temperature resistant filler: 20 parts, selected from: mica powder and silica compound, mass ratio 1:1, particle size D50 is 5μm, mica powder is purchased from: Hebei Huayuan Mining Co., Ltd., silica is purchased from: Bohuas Nanotechnology (Ningbo) Co., Ltd.

[0051] Solvent: 40 parts, selected from: diethylene glycol butyl ether and terpineol compound, mass ratio 3:1. Diethylene glycol butyl ether was purchased from: Shanghai Aladdin Biochemical Technology Co., Ltd., and terpineol was purchased from: Jiangxi Baicao Pharmaceutical Co., Ltd.

[0052] Additives: 3 parts, selected from BYK-333, BYK-055 and EFKA-4310 in a mass ratio of 1.5:0.8:1.5. BYK-333 and BYK-055 were purchased from BYK Additives (Shanghai) Co., Ltd., and EFKA-4310 was purchased from Hangzhou Jessica Chemical Co., Ltd.

[0053] Weathering agent: 2 parts, selected from: weathering agent 1 synthesized in preparation example 1.

[0054] 2. Preparation method:

[0055] S1: Add half of the total amount of solvent (20 parts) and all the additives (3 parts) to the reactor, stir at 400 rpm for 10 minutes to obtain a uniform and transparent material A;

[0056] S2: Add 20 parts of high-temperature resistant filler to material A and disperse it at high speed of 1200 rpm for 30 minutes. During the dispersion process, the material temperature is controlled to be ≤40℃ by circulating water cooling to obtain uniform slurry material B.

[0057] S3: Reduce the rotation speed to 500 rpm, introduce nitrogen into the reactor to replace the air, and add epoxy modified silicone resin (30 parts), weathering agent 1 (2 parts) and the remaining solvent (20 parts) in sequence. Stir for 45 minutes under nitrogen atmosphere to obtain a viscous and uniform material C. Filter through a 50-mesh filter to obtain a carbon fiber carbonization protective ink.

[0058] Examples 2-6

[0059] The preparation of a carbon fiber carbonization protective ink is carried out by referring to the preparation method of Example 1, except that the weathering agent is replaced with weathering agent 2-weathering agent 6 prepared in Preparation Examples 2-6, and the rest is the same as in Example 1.

[0060] Comparative Example 1

[0061] The preparation of a carbon fiber carbonization protective ink is carried out according to the preparation method of Example 1, except that the weathering agent is replaced with a light stabilizer (CAS: 106990-43-6), and the rest is the same as in Example 1.

[0062] Comparative Example 2

[0063] The preparation of a carbon fiber carbonization protective ink is carried out by referring to the preparation method of Example 1, except that the weathering agent is replaced with light stabilizer 770 (CAS: 52829-07-9), and the rest is the same as in Example 1.

[0064] Comparative Example 3

[0065] The preparation of a carbon fiber carbonization protective ink is the same as in Example 1, except that the weather-resistant agent is not added.

[0066] Comparative Example 4

[0067] The preparation of a carbon fiber carbonization protective ink is based on the preparation method of Example 1, except that the mass fraction of the high-temperature resistant filler is replaced with 5 parts (mica powder and silica compounded in a mass ratio of 1:1), and the rest remains the same as in Example 1.

[0068] Performance testing:

[0069] Test specimen: A carbon fiber carbonization protective ink prepared in the examples and comparative examples.

[0070] 1. Properties test of carbon fiber carbonization protective ink:

[0071] Viscosity test: conducted according to national standard GB / T 2794-2013, data are shown in Table 2;

[0072] The test sample was placed in a 100℃ constant temperature chamber and irradiated with a UV-A lamp for 30 days. The viscosity was tested and the viscosity retention rate was calculated according to GB / T 2794-2013. The data are shown in Table 2.

[0073] The test sample was placed in a 50℃ constant temperature chamber and left to stand for 100 days. The sedimentation phenomenon was observed and the data are shown in Table 2.

[0074] 2. Determine the breakage of the raw yarn during the pre-oxidation process as follows: Observe whether there is any breakage during the pre-oxidation process; conduct fineness testing of the elastic composite fiber according to the national standard GB / T 14343-2008, and the data are shown in Table 2;

[0075] The test sample was placed in a 100℃ constant temperature chamber and irradiated with a UV-A lamp for 30 days before being used in the pre-oxidation process for fineness testing. The data are shown in Table 2.

[0076] Table 2

[0077]

[0078] As shown in Table 2, the example group (samples using the weathering agent of this invention) exhibited a stable and positive trend across all performance indicators. Specifically, key protective properties (such as viscosity retention, filament breakage control, and fineness stability) were highly consistent, and resistance to aging environments was strong. Conversely, the comparative group (samples not using the weathering agent of this invention) showed a negative trend: viscosity retention decreased significantly, fineness stability deteriorated after aging, and filament breakage occurred. This indicates that the introduction of the weathering agent of this invention significantly improves the long-term storage stability and protective effect of the ink.

[0079] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A carbon fiber carbonization protective ink, characterized in that, It is prepared from the following raw materials in parts by weight: 20-40 parts epoxy modified silicone resin, 10-30 parts high temperature resistant filler, 30-50 parts solvent, 1-5 parts additives, and 1.5-3 parts weather resistant agent; The weather-resistant agent is a compound represented by Formula 1: Formula 1: ; R1 in Formula 1 is a substituent; R1 is selected from: amino, halogen, phenyl, C1-C5 alkyl, C1-C5 alkoxy; The epoxy-modified silicone resin has an epoxy value of 0.06-0.16 and a solid content of 50±1%. The high-temperature resistant filler is selected from one or more of the following: mica powder, talc powder, kaolin, and silica. The particle size D50 of the high-temperature resistant filler is 1-10 μm; The solvent is selected from one or more of the following: diethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol phenyl ether, and terpineol; The additives are selected from BYK-333, BYK-055 and EFKA-4310, and the mass ratio of the three is (1-2):(0.5-1):(1-2).

2. The carbon fiber carbonization protective ink according to claim 1, characterized in that, The halogen is selected from: chlorine.

3. The carbon fiber carbonization protective ink according to claim 1, characterized in that, The C1-C5 alkyl groups are selected from: methyl, ethyl, propyl, isopropyl, and tert-butyl. The alkoxy groups of C1-C5 are selected from: methoxy and ethoxy.

4. The carbon fiber carbonization protective ink according to claim 1, characterized in that, The weather-resistant agent is selected from one or more of the compounds shown in the following structures; ； ； 。 5. A method for preparing a carbon fiber carbonization protective ink according to any one of claims 1-4, characterized in that, Includes the following steps: S1: Add 1 / 2 part by mass of the solvent and all the additives to the reactor, and stir at a speed of 300-500 rpm for 5-15 minutes to obtain material A; S2: Add high-temperature resistant filler to material A and disperse at 1000-1500 rpm for 20-40 minutes to obtain material B; S3: Adjust the rotation speed to 400-600 rpm, add the epoxy-modified silicone resin, weathering agent and 1 / 2 part by mass of solvent to the system under nitrogen atmosphere, stir at 400-600 rpm for 30-60 minutes to obtain material C, filter, and obtain the carbon fiber carbonization protective ink.

6. The method for preparing a carbon fiber carbonization protective ink according to claim 5, characterized in that, The temperature of the dispersed material in S2 is below 40°C.

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