An oxidized carbon black composite material and its application in coatings

Abstract

The present invention discloses an oxidized carbon black composite material and its application in coatings, belonging to the technical field of carbon black material production. The present invention achieves three major breakthroughs in the prepared coating by performing a three-layer gradient design of a carboxylation core → a dual-functionalized middle layer (hyperbranched + epoxy) → a polyaniline / DBSA shell on the oxidized carbon black composite material: compatibility of dispersibility and conductivity: sedimentation rate ≤1.9% (to solve agglomeration), resistance ≤3.5×10 4 Ω / sq (building an efficient conductive network); stability in wet and hot environments: resistance change rate ≤+9.1% (epoxy and DBSA work together to resist wet and hot degradation); environmental protection and waste reduction: dispersant is replaced with bio-based materials (APG06) without affecting performance.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon black material production, and particularly relates to an oxidized carbon black composite material and its application in coatings. Background Art

[0002] Conductive coatings are widely used in electronic equipment casings, automotive interiors, industrial floors and other fields, and antistatic functions are achieved by adding conductive fillers (such as carbon black). Acrylic resin has become a commonly used matrix due to its weather resistance and film-forming properties, but carbon black is easy to agglomerate in the resin, resulting in uneven conductivity of the coating and decreased adhesion. Although traditional oxidized carbon black is treated with acid to improve dispersibility, its surface inert groups have poor compatibility with acrylic resin, and a large amount of dispersant needs to be added, resulting in a decrease in the solid content of the coating and deterioration of film-forming properties. At the same time, it is difficult for a single modified carbon black to take into account both dispersibility and conductivity (such as the Chinese invention patent "A high-strength conductive plastic and its preparation method" with application number CN202210482604.9, in which the conductive plastic needs to be compounded with carbon nanotubes and modified conductive carbon black to take into account conductivity).

[0003] With the increasing demand for thin-layer high-conductivity coatings for precision electronic devices, it is urgent to develop a carbon black composite material that has both high dispersibility and high conductivity and is chemically bonded to acrylic resin. However, the existing technology still has the following objective problems that have not been fully solved: (1) Poor long-term conductivity stability: The conductivity of carbon black composite materials is easily degraded in hot and humid environments (such as relative humidity > 85% or temperature > 60°C), resulting in coating performance failure; (2) Insufficient environmental protection: Traditional dispersants (such as nonylphenol polyoxyethylene ether) contain harmful substances, increasing the environmental burden; (3) Severe storage sedimentation: The filler has a high sedimentation rate after being left in the coating, affecting the consistency of construction. The root cause of these problems is the lack of multifunctional coordinated design of the composite material, which cannot simultaneously optimize the dispersion, conductivity and chemical bonding mechanisms. Summary of the Invention

[0004] The purpose of the present invention is to provide an oxidized carbon black composite material and its application in coatings, and to achieve a synergistic effect between the raw materials by performing multi-layer functionalization improvements on the oxidized carbon black composite material. Specifically, through a three-layer gradient design with a carboxyl core, a bifunctionalized middle layer (with both a hyperbranched structure and epoxy groups), and a polyaniline-doped outer shell, the problems of agglomeration, poor dispersibility, and uneven conductivity in the background technology are solved, and the problems of poor long-term conductive stability and insufficient environmental protection are also overcome. This synergistic effect is reflected in:

[0005] To address the agglomeration problem: the hyperbranched structure of the middle layer provides steric hindrance to reduce physical agglomeration; at the same time, the epoxy groups chemically bond with the acrylic resin to enhance compatibility.

[0006] Regarding the conductivity problem: doping the polyaniline shell to form a continuous conductive network, and improving the conductivity efficiency and stability by doping with acid.

[0007] Targeting additional issues: (1) Long-term conductivity stability: The doping acid and epoxy groups work synergistically to stabilize the conductive network in hot and humid environments, preventing degradation. (2) Environmental friendliness: The amount of harmful dispersants used is reduced (from 2% to 0.5%), and the self-dispersion of epoxy groups reduces environmental load. (3) Storage sedimentation: The hyperbranched structure enhances the filler's suspension force, significantly reducing sedimentation rate.

[0008] The synergistic effect is manifested in the following ways: the modifications of each layer reinforce each other - the epoxy groups in the middle layer not only improve dispersion, but also promote the electronic conduction of the polyaniline in the outer shell; the overall design reduces dependence on dispersants, increases the solid content of the coating, and achieves a "1+1>2" effect.

[0009] The above objectives can be achieved through the following technical solutions:

[0010] An oxidized carbon black composite material is prepared by the following steps:

[0011] S1. Mix carbon black with concentrated nitric acid, reflux at a constant temperature of 85-100°C for 4-5 hours, cool, wash with deionized water until neutral, and then vacuum dry at 60-100°C for 12 hours to obtain carboxylated carbon black;

[0012] S21, dispersing carboxylated carbon black in anhydrous ethanol, ultrasonically dispersing for 30 minutes, adding γ-aminopropyltriethoxysilane thereto, stirring at 85-100° C. for 3-5 hours, centrifuging, washing with anhydrous ethanol three times, and drying at 60-100° C. to obtain silanized carbon black;

[0013] S22, dispersing silanized carbon black in anhydrous ethanol, adding hyperbranched polyester, 3-glycidyloxypropyltrimethoxysilane and dibutyltin dilaurate thereto, reacting at 50° C. for 5-6 hours under nitrogen protection, and after completion, centrifuging, washing with anhydrous ethanol three times, and vacuum drying at 60-100° C. for 12 hours to obtain bifunctional carbon black;

[0014] S3. Disperse the bifunctional carbon black in hydrochloric acid, ultrasonically disperse for 30 minutes, then add aniline and dodecylbenzenesulfonic acid, stir for 10 minutes, cool to 2°C, add ammonium persulfate, stir and react at a constant temperature of 2°C for 5-6 hours. After completion, centrifuge, wash with deionized water until neutral, and vacuum dry at 60-100°C for 12 hours to obtain an oxidized carbon black composite material.

[0015] Furthermore, the particle size of the carbon black in S1 is 30 nm; and the volume fraction of the concentrated nitric acid is 65%.

[0016] Furthermore, the usage ratio of carbon black and concentrated nitric acid in S1 is 20g:200mL.

[0017] Furthermore, the model of the hyperbranched polyester in S21 is Specialty Boltorn H2004.

[0018] Furthermore, the usage ratio of the carboxylated carbon black, anhydrous ethanol, and γ-aminopropyltriethoxysilane in S21 is 5 g:100 mL:2 g.

[0019] Furthermore, the usage ratio of the silanized carbon black, anhydrous ethanol, hyperbranched polyester, 3-glycidyloxypropyltrimethoxysilane, and dibutyltin dilaurate in S22 is 5g:100mL:10-15g:3-5g:0.1-0.2g.

[0020] Furthermore, the molar concentration of the hydrochloric acid in S3 is 0.5 mol / L.

[0021] Furthermore, the usage ratio of the bifunctionalized carbon black, hydrochloric acid, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate in S3 is 10 g:100 mL:5-10 g:2-3 g:11.4-12.0 g.

[0022] The above-mentioned S1 function: the carboxyl group provides active grafting sites and enhances subsequent reactivity.

[0023] The above-mentioned S21-22 functions: The above-mentioned bifunctional carbon black has both hyperbranched structure and epoxy groups, wherein the hyperbranched structure provides steric hindrance to prevent agglomeration; the epoxy groups are chemically bonded to the acrylic resin to improve compatibility; and the conductive stability is synergistically enhanced.

[0024] The above-mentioned S3 functions: doping with dodecylbenzenesulfonic acid improves the conductive efficiency and wet-heat stability of polyaniline; and cooperates with the epoxy groups in the intermediate layer to form a continuous conductive network.

[0025] Structural characteristics of the oxidized carbon black composite material prepared above:

[0026] Core: carboxylated carbon black (provides active sites).

[0027] Middle layer: bifunctional hyperbranched polysiloxane (hyperbranched structure prevents agglomeration, epoxy groups are bonded to the resin).

[0028] Shell: DBSA-doped polyaniline (high conductivity, enhanced stability).

[0029] Synergistic Mechanism: The epoxy groups in the middle layer undergo a ring-opening reaction with the acrylic resin to form covalent bonds, reducing the need for dispersants. The acid-doped outer shell synergizes with the middle layer to protect against the effects of humid and hot environments. This overall improves filler loading efficiency, allowing a 30% reduction in filler dosage while maintaining high performance. The composite material achieves a grafting rate >90%, and a sedimentation rate of <2% after 168 hours in the resin (conventional >50%).

[0030] Furthermore, the application of the oxidized carbon black composite material in coatings comprises the following steps:

[0031] The coating's mass percentage formula is: 8% to 12% oxidized carbon black composite material, 8% to 12% acrylic resin, 0.5% dispersant, 0.5% bio-based dispersant, 1% 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2% silane coupling agent KH-460, and 76% pure water;

[0032] Preparation method: Weigh the above raw materials according to mass percentage, add the oxidized carbon black composite material and pure water into a sand mill, then add a dispersant, a bio-based dispersant and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate thereto, disperse at 1500-3000 r / min for 1-2 hours, then add acrylic resin and silane coupling agent KH-460 thereto, continue stirring at 1500-3000 r / min for 2-4 hours to obtain a coating.

[0033] Furthermore, the solid content of the acrylic resin is 50%; the model of the dispersant is BYK-190; and the bio-based dispersant is alkyl polyglycoside APG06.

[0034] The beneficial effects of the present invention are analyzed as follows:

[0035] (1) Significantly improve the long-term conductivity stability of the coating (solve the problem of failure in hot and humid environments):

[0036] Core data support: After aging for 168 hours at 85% RH / 60°C, the resistance change rate of Examples 4 to 6 is only +7.2% to +9.1%, which is much lower than that of Comparative Example 8 (+32.7%) and Comparative Example 10 (+68.9%).

[0037] Analysis of technical principles: Key components work synergistically: The DBSA-doped polyaniline in the outer shell (Example S3) provides a basic conductive network, while the epoxy groups in the middle layer (from KH-560) are chemically bonded to the acrylic resin (S22), forming a stable structure that resists moisture and heat stratification. The absence of any component (such as comparative example 8 without epoxy groups and comparative example 10 without DBSA) results in a sudden increase in the resistance change rate (>25%). Indirect contribution of the hyperbranched structure: The resistance change rate of comparative example 7 (missing hyperbranched polyester) reaches +25.6%, proving that the hyperbranched structure indirectly maintains the stability of the conductive network by improving dispersion uniformity (sedimentation rate 12.3%).

[0038] (2) Breaking through the compatibility barrier between dispersibility and conductivity (solving the "agglomeration-conductivity contradiction" of traditional fillers):

[0039] Dispersion optimization (sedimentation rate ≤ 2%): The sedimentation rates of Examples 4 to 6 are only 1.5% to 1.9%, while that of conventional carboxylated carbon black (Comparative Example 12) is as high as 53.2%.

[0040] Core mechanism: The dual-functional design of the middle layer (hyperbranched structure + epoxy group) provides double protection: the steric hindrance of the hyperbranched polyester reduces physical agglomeration (compared with the sedimentation rate of 12.3% in comparative example 7); the epoxy group chemically bonds with the resin to enhance compatibility (compared with the sedimentation rate of 6.1% in comparative example 8).

[0041] Conductivity optimization (10 4 Ω / sq level): Examples 4 to 6 surface resistance 2.8 to 3.5×10 4 Ω / sq, while the comparative example 11 (without polyaniline) without the conductive shell increased to 6.5×10 8 Ω / sq.

[0042] Key breakthrough: The present invention constructs a continuous conductive network (S3) through the polyaniline / DBSA shell, which is not affected by the type of dispersant (Comparative Example 13 resistance 2.9×10 4 Ω / sq is equivalent to that in the embodiment).

[0043] (3) Achieve the unity of environmental protection and high performance (reduce dependence on harmful dispersants):

[0044] Improved environmental performance: Comparative Example 13 (using traditional dispersant NP-40) has similar performance to Example 5, proving that the present invention only requires 0.5% of bio-based dispersant (APG06) to achieve the same dispersion effect (sedimentation rate 1.6% vs. 1.5%).

[0045] Synergistic waste reduction mechanism: The chemical bonding of the epoxy groups in the middle layer reduces dependence on dispersants (traditional solutions require 2% dispersants); the bio-based dispersant APG06 replaces nonylphenol polyoxyethylene ether (NP-40), avoiding environmentally harmful substances from the source.

[0046] (4) Synergistic effect of three-layer gradient design (verification of the "1+1>2" effect):

[0047] Necessity of the core: Carboxylated carbon black (S1) provides active sites. The performance of comparative example 12, which lacks the middle layer / shell, deteriorates overall (sedimentation rate 53.2%, electrical resistance 9.8×10 8 Ω / sq).

[0048] Core position of the intermediate layer: Due to the lack of the intermediate layer, the sedimentation rate (25.6%) and resistance change rate (+41.3%) of Comparative Example 9 (silanized carbon black only) are significantly inferior to those of the embodiment.

[0049] The shell is irreplaceable: the resistance of comparative example 10 (without DBSA) soars to 1.2×10 8 Ω / sq, proving the decisive role of DBSA doping on the conductivity of polyaniline.

[0050] Conclusion: The present invention achieves three major breakthroughs through a three-layer gradient design of carboxyl core → bifunctionalized middle layer (hyperbranched + epoxy) → polyaniline / DBSA shell: compatibility of dispersibility and conductivity: sedimentation rate ≤1.9% (to solve agglomeration), resistance ≤3.5×10 4 Ω / sq (building an efficient conductive network); stability in wet and hot environments: resistance change rate ≤+9.1% (epoxy and DBSA work together to resist wet and hot degradation); environmental protection and waste reduction: dispersant is replaced with bio-based materials (APG06) without affecting performance. DETAILED DESCRIPTION

[0051] Below in conjunction with the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is obvious that described embodiment is only a part of embodiment of the present invention, rather than whole embodiment. Based on the embodiment in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work premise all fall within the scope of protection of the present invention. Meanwhile, raw materials, reagents or devices used in the following examples, unless otherwise specified, can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0052] Example 1

[0053] Preparation of oxidized carbon black composite materials (all raw materials are commercially available, specifications see instructions):

[0054] S1. Preparation of carboxylated carbon black (core functionalization):

[0055] Raw materials: carbon black (particle size 30 nm, purity >99%, Maclean); concentrated nitric acid (volume fraction 65%, analytical grade, Maclean).

[0056] Steps: Mix 20g of carbon black with 200mL of concentrated nitric acid, place in a reflux apparatus, and reflux at 85°C for 4 hours. After cooling, wash with deionized water until neutral (pH = 7 as determined by pH paper), and then vacuum dry at 60°C for 12 hours to obtain carboxylated carbon black.

[0057] S2. Preparation of bifunctional carbon black (bifunctional hyperbranched polysiloxane grafting, intermediate layer):

[0058] Raw materials: carboxylated carbon black (S1 product); γ-aminopropyltriethoxysilane (KH-550, purity 98%, Maclean); 3-glycidoxypropyltrimethoxysilane (KH-560, purity 97%, Maclean); hyperbranched polyester (SpecialtyBoltorn H2004); dibutyltin dilaurate (catalyst, purity 95%, Maclean); anhydrous ethanol (analytical grade, Sinopharm Group).

[0059] step:

[0060] a. Silanization: Disperse 5 g of carboxylated carbon black in 100 mL of anhydrous ethanol and ultrasonically disperse for 30 min (300 W) until uniform. Add 2 g of γ-aminopropyltriethoxysilane and stir at 85°C for 3 h. Centrifuge, wash three times with anhydrous ethanol, and dry at 60°C to obtain the silanized carbon black.

[0061] b. Functionalized Hyperbranching: Disperse 5g of silanized carbon black in 100mL of anhydrous ethanol, add 10g of hyperbranched polyester, 3g of 3-glycidoxypropyltrimethoxysilane, and 0.1g of dibutyltin dilaurate, and react at 50°C under nitrogen for 5h. After the reaction, centrifuge, wash three times with anhydrous ethanol, and vacuum dry at 60°C for 12h to obtain a bifunctionalized carbon black (containing both a hyperbranched structure and epoxy groups).

[0062] S3. Preparation of oxidized carbon black composite material (doped with polyaniline coating, high conductivity and stability of the shell):

[0063] Raw materials: bifunctional carbon black (S2 product); aniline (purity ≥99.5%, Maclean); ammonium persulfate (APS, purity 98.5%, Maclean); dodecylbenzenesulfonic acid (DBSA, purity 90%, Maclean); hydrochloric acid (0.5 mol / L, analytical grade, Sinopharm Group).

[0064] Steps: Disperse 10g of bifunctionalized carbon black in 100mL of hydrochloric acid and ultrasonically disperse for 30min (power 300W) until uniform. Add 5g of aniline and 2g of dodecylbenzenesulfonic acid and stir for 10min. Cool to 2°C (ice-water bath), add 11.4g of ammonium persulfate (dissolved in 20mL of deionized water), and stir at a constant temperature of 2°C for 5h. After the reaction is completed, centrifuge, wash with deionized water until neutral, and vacuum dry at 60°C for 12h to obtain an oxidized carbon black composite material (polyaniline shell doped with DBSA).

[0065] Example 2

[0066] Preparation of oxidized carbon black composite materials (all raw materials are commercially available, specifications see instructions):

[0067] S1. Preparation of carboxylated carbon black (core functionalization):

[0068] Raw materials: carbon black (particle size 30 nm, purity >99%, Maclean); concentrated nitric acid (volume fraction 65%, analytical grade, Maclean).

[0069] Steps: Mix 20g of carbon black with 200mL of concentrated nitric acid, place in a reflux apparatus, and reflux at 90°C for 5 hours. After cooling, wash with deionized water until neutral (pH = 7 as determined by pH paper), and then vacuum dry at 80°C for 12 hours to obtain carboxylated carbon black.

[0070] S2. Preparation of bifunctional carbon black (bifunctional hyperbranched polysiloxane grafting, intermediate layer):

[0071] Raw materials: carboxylated carbon black (S1 product); γ-aminopropyltriethoxysilane (KH-550, purity 98%, Maclean); 3-glycidoxypropyltrimethoxysilane (KH-560, purity 97%, Maclean); hyperbranched polyester (SpecialtyBoltorn H2004); dibutyltin dilaurate (catalyst, purity 95%, Maclean); anhydrous ethanol (analytical grade, Sinopharm Group).

[0072] step:

[0073] a. Silanization: Disperse 5 g of carboxylated carbon black in 100 mL of anhydrous ethanol and ultrasonically disperse for 30 min (300 W) until uniform. Add 2 g of γ-aminopropyltriethoxysilane and stir at 90°C for 5 h. Centrifuge, wash three times with anhydrous ethanol, and dry at 80°C to obtain the silanized carbon black.

[0074] b. Functionalized Hyperbranching: 5g of silanized carbon black was dispersed in 100mL of anhydrous ethanol. 12g of hyperbranched polyester, 4g of 3-glycidoxypropyltrimethoxysilane, and 0.2g of dibutyltin dilaurate were added. The mixture was reacted at 50°C under nitrogen for 6h. After the reaction, the mixture was centrifuged, washed three times with anhydrous ethanol, and dried under vacuum at 80°C for 12h to obtain a bifunctionalized carbon black (containing both a hyperbranched structure and epoxy groups).

[0075] S3. Preparation of oxidized carbon black composite material (doped with polyaniline coating, high conductivity and stability of the shell):

[0076] Raw materials: bifunctional carbon black (S2 product); aniline (purity ≥99.5%, Maclean); ammonium persulfate (APS, purity 98.5%, Maclean); dodecylbenzenesulfonic acid (DBSA, purity 90%, Maclean); hydrochloric acid (0.5 mol / L, analytical grade, Sinopharm Group).

[0077] Steps: Disperse 10g of bifunctionalized carbon black in 100mL of hydrochloric acid and ultrasonically disperse for 30min (power 300W) until uniform. Add 8g of aniline and 3g of dodecylbenzenesulfonic acid and stir for 10min. Cool to 2°C (ice-water bath), add 11.8g of ammonium persulfate (dissolved in 20mL of deionized water), and stir at a constant temperature of 2°C for 6h. After the reaction is completed, centrifuge, wash with deionized water until neutral, and vacuum dry at 80°C for 12h to obtain an oxidized carbon black composite material (polyaniline shell doped with DBSA).

[0078] Example 3

[0079] Preparation of oxidized carbon black composite materials (all raw materials are commercially available, specifications see instructions):

[0080] S1. Preparation of carboxylated carbon black (core functionalization):

[0081] Raw materials: carbon black (particle size 30 nm, purity >99%, Maclean); concentrated nitric acid (volume fraction 65%, analytical grade, Maclean).

[0082] Steps: Mix 20g of carbon black with 200mL of concentrated nitric acid, place in a reflux apparatus, and reflux at 100°C for 5 hours. After cooling, wash with deionized water until neutral (pH = 7 as determined by pH paper), and then vacuum dry at 100°C for 12 hours to obtain carboxylated carbon black.

[0083] S2. Preparation of bifunctional carbon black (bifunctional hyperbranched polysiloxane grafting, intermediate layer):

[0084] Raw materials: carboxylated carbon black (S1 product); γ-aminopropyltriethoxysilane (KH-550, purity 98%, Maclean); 3-glycidoxypropyltrimethoxysilane (KH-560, purity 97%, Maclean); hyperbranched polyester (SpecialtyBoltorn H2004); dibutyltin dilaurate (catalyst, purity 95%, Maclean); anhydrous ethanol (analytical grade, Sinopharm Group).

[0085] step:

[0086] a. Silanization: Disperse 5g of carboxylated carbon black in 100mL of anhydrous ethanol and ultrasonically disperse for 30 minutes (300W) until uniform. Add 2g of γ-aminopropyltriethoxysilane and stir at 100°C for 5 hours. Centrifuge, wash three times with anhydrous ethanol, and dry at 100°C to obtain the silanized carbon black.

[0087] b. Functionalized Hyperbranching: 5g of silanized carbon black was dispersed in 100mL of anhydrous ethanol. 15g of hyperbranched polyester, 5g of 3-glycidoxypropyltrimethoxysilane, and 0.2g of dibutyltin dilaurate were added. The mixture was reacted at 50°C under nitrogen for 6h. After completion of the reaction, the mixture was centrifuged, washed three times with anhydrous ethanol, and dried under vacuum at 100°C for 12h to obtain a bifunctionalized carbon black (containing both a hyperbranched structure and epoxy groups).

[0088] S3. Preparation of oxidized carbon black composite material (doped with polyaniline coating, high conductivity and stability of the shell):

[0089] Raw materials: bifunctional carbon black (S2 product); aniline (purity ≥99.5%, Maclean); ammonium persulfate (APS, purity 98.5%, Maclean); dodecylbenzenesulfonic acid (DBSA, purity 90%, Maclean); hydrochloric acid (0.5 mol / L, analytical grade, Sinopharm Group).

[0090] Steps: Disperse 10g of bifunctionalized carbon black in 100mL of hydrochloric acid and ultrasonically disperse for 30min (power 300W) until uniform. Add 10g of aniline and 3g of dodecylbenzenesulfonic acid and stir for 10min. Cool to 2°C (ice-water bath), add 12.0g of ammonium persulfate (dissolved in 20mL of deionized water), and stir at a constant temperature of 2°C for 6h. After the reaction is completed, centrifuge, wash with deionized water until neutral, and vacuum dry at 100°C for 12h to obtain an oxidized carbon black composite material (polyaniline shell doped with DBSA).

[0091] Comparative Example 1

[0092] Comparative Example 1 is the control group of Example 2. The raw material "12g hyperbranched polyester" in S2 in Example 2 is removed, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 2, and finally an oxidized carbon black composite material is obtained.

[0093] Comparative Example 2

[0094] Comparative Example 2 is the control group of Example 2. The raw material "4 g of 3-glycidyloxypropyltrimethoxysilane" in S2 in Example 2 is removed, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 2, and finally an oxidized carbon black composite material is obtained.

[0095] Comparative Example 3

[0096] Comparative Example 3 is the control group of Example 2, except that the step "b. Functionalized hyperbranching" process in S2 in Example 2 is removed, that is, the raw material "bifunctionalized carbon black" in S3 is replaced by the "silanized carbon black" in S2, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 2, and finally an oxidized carbon black composite material is obtained.

[0097] Comparative Example 4

[0098] Comparative Example 4 is the control group of Example 2. The raw material "3 g of dodecylbenzenesulfonic acid" in S3 of Example 2 is removed, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 2, and finally an oxidized carbon black composite material is obtained.

[0099] Comparative Example 5

[0100] Comparative Example 5 is the control group of Example 2. The preparation process of the S3 oxidized carbon black composite material in Example 2 is removed, and the remaining raw materials, raw material amounts and preparation steps are kept consistent with those in Example 2, and finally a bifunctional carbon black is obtained.

[0101] Comparative Example 6

[0102] Comparative Example 6 is the control group of Example 2. The preparation processes of S2 bifunctional carbon black and S3 oxidized carbon black composite material in Example 2 are removed, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 2, and finally carboxylated carbon black is obtained.

[0103] Example 4

[0104] An application of an oxidized carbon black composite material in a coating comprises the following steps:

[0105] Coating formula (mass percentage): 8% oxidized carbon black composite material prepared in Example 1, 12% acrylic resin (solid content 50%, model ACR-1688, Mitsubishi Chemical), 0.5% dispersant (model BYK-190, BYK Chemical), 0.5% bio-based dispersant (alkyl polyglycoside APG06, 75% in H2O, McLean), 1% 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (alcohol ester dodecahydrate, purity 99%, McLean), 2% silane coupling agent KH-460 (Suzhou Patna), and 76% pure water.

[0106] Preparation method: Weigh the raw materials by mass percentage. Add the oxidized carbon black composite material prepared in Example 1 and pure water to a sand mill. Add a dispersant, a bio-based dispersant, and 2,2,4-trimethylpentanediol monoisobutyrate. Disperse at 1500 rpm for 1 hour. Then, add acrylic resin and silane coupling agent KH-460. Continue stirring at 1500 rpm for 2 hours to obtain a coating.

[0107] Example 5

[0108] An application of an oxidized carbon black composite material in a coating comprises the following steps:

[0109] Coating formula (mass percentage): 10% oxidized carbon black composite material prepared in Example 2, 10% acrylic resin (solid content 50%, model ACR-1688, Mitsubishi Chemical), 0.5% dispersant (model BYK-190, BYK Chemical), 0.5% bio-based dispersant (alkyl polyglycoside APG06, 75% in H2O, McLean), 1% 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (alcohol ester dodecahydrate, purity 99%, McLean), 2% silane coupling agent KH-460 (Suzhou Patna), and 76% pure water.

[0110] Preparation method: Weigh the raw materials by mass percentage. Add the oxidized carbon black composite material prepared in Example 2 and pure water to a sand mill. Add a dispersant, a bio-based dispersant, and 2,2,4-trimethylpentanediol monoisobutyrate. Disperse at 2000 rpm for 2 hours. Then, add acrylic resin and silane coupling agent KH-460. Continue stirring at 2000 rpm for 4 hours to obtain a coating.

[0111] Example 6

[0112] An application of an oxidized carbon black composite material in a coating comprises the following steps:

[0113] Coating formula (mass percentage): 12% oxidized carbon black composite material prepared in Example 3, 8% acrylic resin (solid content 50%, model ACR-1688, Mitsubishi Chemical), 0.5% dispersant (model BYK-190, BYK Chemical), 0.5% bio-based dispersant (alkyl polyglycoside APG06, 75% in H2O, McLean), 1% 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (alcohol ester dodecahydrate, purity 99%, McLean), 2% silane coupling agent KH-460 (Suzhou Patna), and 76% pure water.

[0114] Preparation method: Weigh the raw materials by mass percentage. Add the oxidized carbon black composite material prepared in Example 3 and pure water to a sand mill. Add a dispersant, a bio-based dispersant, and 2,2,4-trimethylpentanediol monoisobutyrate. Disperse at 3000 rpm for 2 hours. Then, add acrylic resin and silane coupling agent KH-460. Continue stirring at 3000 rpm for 4 hours to obtain a coating.

[0115] Comparative Example 7

[0116] Comparative Example 7 is the control group of Example 5, except that the raw material "oxidized carbon black composite material prepared in Example 2" in Example 5 is replaced by the oxidized carbon black composite material prepared in Comparative Example 1, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0117] Comparative Example 8

[0118] Comparative Example 8 is the control group of Example 5, in which the raw material "oxidized carbon black composite material prepared in Example 2" in Example 5 is replaced by the oxidized carbon black composite material prepared in Comparative Example 2, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0119] Comparative Example 9

[0120] Comparative Example 9 is the control group of Example 5, in which the raw material "oxidized carbon black composite material prepared in Example 2" in Example 5 is replaced by the oxidized carbon black composite material prepared in Comparative Example 3, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0121] Comparative Example 10

[0122] Comparative Example 10 is the control group of Example 5, in which the raw material "oxidized carbon black composite material prepared in Example 2" in Example 5 is replaced by the oxidized carbon black composite material prepared in Comparative Example 4, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0123] Comparative Example 11

[0124] Comparative Example 11 is the control group of Example 5, in which the raw material "oxidized carbon black composite material prepared in Example 2" in Example 5 is replaced with the bifunctional carbon black prepared in Comparative Example 5, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0125] Comparative Example 12

[0126] Comparative Example 12 is the control group of Example 5, except that the raw material "oxidized carbon black composite material prepared in Example 2" in Example 5 is replaced by the carboxylated carbon black prepared in Comparative Example 6, and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0127] Comparative Example 13

[0128] Comparative Example 13 is the control group of Example 5, except that the raw material "bio-based dispersant (alkyl polyglycoside APG06, 75% in H2O, McLean)" in Example 5 is replaced by a traditional dispersant nonylphenol polyoxyethylene ether (NP-40, McLean), and the remaining raw materials, raw material amounts and preparation steps remain the same as in Example 5, and finally a coating is obtained.

[0129] The coatings prepared in Examples 4 to 6 and Comparative Examples 7 to 13 were subjected to performance tests. The performance test process is as follows, and the test results are shown in Table 1:

[0130] (1) Sedimentation rate test (to evaluate dispersibility):

[0131] Test process: Take 50mL of paint sample in a measuring cylinder, let it stand for 168 hours (7 days), and record the sedimentation height (h s ) and initial height (h0). Sedimentation rate = (h s / h0)×100%.

[0132] (2) Surface resistance test (to evaluate conductivity):

[0133] Test Procedure: Apply the coating to a glass substrate (100 μm wet film thickness) and allow to dry at room temperature for 24 hours to form a film. Measure the surface resistance (Ω / sq) using a four-probe resistance meter (e.g., ST2253). Take the average of five points.

[0134] (3) Long-term conductivity stability test (evaluation of performance in hot and humid environments):

[0135] Test process: The coating sample was placed in a constant temperature and humidity chamber (85% RH, 60°C) and aged for 168 hours. The surface resistance before and after aging was measured, and the resistance change rate was calculated as [(R 老化后 -R 初始 ) / R 初始 ]×100%.

[0136] Table 1 Test results

[0137]

[0138] According to the data analysis in Table 1:

[0139] (1) Sedimentation rate analysis (dispersion evaluation): Sedimentation rate reflects the dispersion stability of fillers in coatings. Low sedimentation rate indicates good dispersion and fillers are not easy to agglomerate.

[0140] Examples 4-6 (sedimentation rates 1.5%-1.9%): Excellent dispersibility. This is due to the following: the bifunctionalized interlayer (hyperbranched polyester + epoxy groups) provides steric hindrance, reducing physical aggregation (e.g., the addition of hyperbranched polyester in S22); and the epoxy groups (derived from 3-glycidoxypropyltrimethoxysilane) chemically bond with the acrylic resin, enhancing compatibility and reducing sedimentation.

[0141] Comparative Example 7 (12.3% sedimentation rate): Using the composite material of Comparative Example 1 (excluding the hyperbranched polyester), the sedimentation rate increased significantly. Reason: The lack of steric hindrance of the hyperbranched structure (hyperbranched polyester was omitted in Technical Solution S22) caused the filler to easily agglomerate.

[0142] Comparative Example 8 (6.1% sedimentation rate): Using the composite material of Comparative Example 2 (without the epoxy groups), the sedimentation rate was higher than that of the example. Reason: The lack of epoxy groups (3-glycidoxypropyltrimethoxysilane was omitted in Technical Solution S22) prevented chemical bonding with the acrylic resin, resulting in reduced compatibility.

[0143] Comparative Example 9 (25.6% sedimentation rate): The composite material of Comparative Example 3 (silanized carbon black only, no intermediate layer) achieved the highest sedimentation rate. Reason: The complete absence of the intermediate layer (no S22 functionalization and hyperbranching) resulted in neither steric hindrance nor chemical bonding, leading to severe agglomeration.

[0144] Comparative Example 10 (2.3% sedimentation rate): Using the composite material from Comparative Example 4 (excluding DBSA), the sedimentation rate was close to that of the example. Reason: DBSA is primarily used for conductivity (doping S3 with polyaniline) and has little effect on dispersibility; the hyperbranched structure of the intermediate layer still provides basic dispersion stability.

[0145] Comparative Example 11 (4.7% sedimentation rate): Using the material from Comparative Example 5 (bifunctionalized carbon black without a polyaniline shell), the sedimentation rate was good but inferior to that of Example 1. Reason: The hyperbranched structure of the middle layer provided some steric hindrance, but lacked the synergistic effect of the polyaniline shell.

[0146] Comparative Example 12 (Sedimentation Rate 53.2%): Using the carboxylated carbon black from Comparative Example 6, the sedimentation rate was extremely high. Reason: Only the core was carboxylated (S1), without modification of the middle layer and outer shell, resulting in severe filler agglomeration.

[0147] Comparative Example 13 (1.6% sedimentation rate): Using the traditional dispersant NP-40, the sedimentation rate was comparable to that of the example. Reason: The change in dispersant did not affect the dispersibility, and the composite's intermediate layer design (hyperbranching + epoxy groups) was still the primary dispersion mechanism.

[0148] Sedimentation Rate Conclusion: The dual functionalization of the intermediate layer (hyperbranched structure + epoxy groups) is key to optimizing dispersibility. Omission of any component (Comparative Examples 7 and 8) or the entire intermediate layer (Comparative Example 9) resulted in a worsened sedimentation rate. The polyaniline / DBSA shell (Comparative Example 10) and dispersant type (Comparative Example 13) had minimal impact on dispersibility, demonstrating the advantage of the invention's reduced dispersant dependency.

[0149] (2) Surface resistance analysis (evaluation of conductivity): Surface resistance reflects the conductivity of the coating, with low values ​​indicating good conductivity.

[0150] Examples 4 to 6 (resistance 2.8 to 3.5 × 10 4 Ω / sq): Excellent electrical conductivity. This is due to the fact that the polyaniline in the outer shell, doped with DBSA (dodecylbenzenesulfonic acid in S3), forms a continuous conductive network, while the epoxy groups in the middle layer (3-glycidoxypropyltrimethoxysilane in S22) promote electron conduction.

[0151] Comparative Example 7 (Resistance 4.1×10 5 Ω / sq): Composites without hyperbranched polyester exhibit increased resistance. Reason: The lack of hyperbranched structure leads to uneven filler dispersion (12.3% sedimentation rate in Table 1), disrupting the continuity of the conductive network.

[0152] Comparative Example 8 (Resistance 3.6×10 4 Ω / sq): Using a composite material without epoxy groups, the resistance is close to that of the example. Reason: Epoxy groups primarily affect dispersion and stability, with little direct impact on conductivity; the polyaniline shell still provides basic conductivity.

[0153] Comparative Example 9 (resistance 8.9×10 5 Ω / sq): The resistance of a composite material containing only silanized carbon black increases significantly. Reason: Without an intermediate layer and outer shell, the conductivity of silanized carbon black alone is insufficient.

[0154] Comparative Example 10 (resistance 1.2×10 8 Ω / sq): Using a composite material without DBSA results in extremely high resistance. Cause: The absence of DBSA (omitted in S3) results in undoped polyaniline, significantly reducing conductivity.

[0155] Comparative Example 11 (Resistance 6.5×10 8Ω / sq): Using bifunctionalized carbon black (without a polyaniline shell), it has one of the highest resistances. Reason: Without the polyaniline conductive shell, relying solely on the carbon black's inherent conductivity is insufficient.

[0156] Comparative Example 12 (resistance 9.8×10 8 Ω / sq): Carboxylated carbon black has the highest resistance. Reason: Without any conductive modification, carbon black agglomeration (sedimentation rate 53.2%) further deteriorates conductivity.

[0157] Comparative Example 13 (resistance 2.9×10 4 Ω / sq): Using a conventional dispersant, the resistance is comparable to that of the example. Reason: Dispersant type does not affect conductivity; conductivity primarily depends on the composite material design.

[0158] Surface resistance conclusion: The polyaniline / DBSA shell is key to conductivity. The absence of DBSA (Comparative Example 10) or the entire shell (Comparative Example 11) leads to a sharp increase in resistance. The hyperbranched structure of the intermediate layer (Comparative Example 7) indirectly affects conductivity by improving dispersion and maintaining network continuity. The presence of epoxy groups (Comparative Example 8) has little direct effect on conductivity.

[0159] (3) Resistance change rate analysis (evaluation of long-term conductive stability): The resistance change rate reflects the performance stability in a hot and humid environment. A low absolute value indicates good stability.

[0160] Examples 4-6 (change rate +7.2% to +9.1%): Excellent stability. This is due to the synergistic effect of DBSA doping (S3) and the epoxy groups in the intermediate layer to maintain the conductive network, while the hyperbranched structure (S22) reduces aggregation and prevents network degradation under heat and humidity.

[0161] Comparative Example 7 (Change +25.6%): Using a composite material without hyperbranched polyester, stability decreased. Reason: The lack of hyperbranched structure leads to uneven dispersion (12.3% sedimentation rate in Table 1), exacerbated agglomeration under damp heat, and increased resistance fluctuation.

[0162] Comparative Example 8 (+32.7% change): Using a composite material without epoxy groups significantly deteriorated its stability. Reason: The lack of epoxy groups (S22 omitted) weakened the chemical bond with the resin, causing the coating to delaminate in hot and humid environments and degrading the conductive network.

[0163] Comparative Example 9 (change rate +41.3%): Worst stability. Reason: No intermediate layer, poor compatibility between filler and resin (settling rate 25.6%), and rapid performance degradation under damp heat.

[0164] Comparative Example 10 (Change +68.9%): Using a composite material without DBSA, the stability was extremely poor. Reason: The lack of DBSA resulted in undoped polyaniline, which easily degraded its conductivity in hot and humid environments.

[0165] Comparative Example 11 (change rate +22.4%): Moderate stability. Reason: The bifunctionalized carbon black has partial stability (hyperbranched structure), but lacks the synergistic protection of polyaniline / DBSA.

[0166] Comparative Example 12 (change rate +37.5%): Poor stability. Reason: No modification, filler agglomeration (sedimentation rate 53.2%) exacerbated performance failure under damp heat.

[0167] Comparative Example 13 (change rate +7.8%): Stability is comparable to that of the Example. Reason: The type of dispersant does not affect stability, and stability mainly depends on the three-layer design of the composite material.

[0168] Conclusions on resistance change rate: DBSA doping (Comparative Example 10) and epoxy groups (Comparative Example 8) are key to stability. The absence of either synergistic component leads to a significant increase in resistance change rate; the hyperbranched structure (Comparative Example 7) indirectly improves stability by improving dispersion.

[0169] Overall analysis summary: Synergy effect of three-layer design:

[0170] Core carboxylation (S1): provides active sites to support subsequent modifications (the worst performance of Example 12 verifies its necessity).

[0171] Dual functionalization of the intermediate layer (S21-S22): The hyperbranched structure (anti-agglomeration) and the epoxy group (chemical bonding) jointly optimize the dispersibility and stability (verified by comparative examples 7-9).

[0172] Shell polyaniline / DBSA (S3): DBSA doping and polyaniline provide high electrical conductivity and wet-heat stability (verified by Comparative Examples 10-11).

[0173] The excellent performance of Examples 4 to 6 (low sedimentation rate, low resistance, and low change rate) demonstrates the "1+1>2" effect of the three-layer design.

[0174] It should be noted that, in this document, terms such as "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0175] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may 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. An oxidized carbon black composite material, characterized in that Prepared by the following steps: S1. Mix carbon black with concentrated nitric acid, reflux at a constant temperature of 85-100°C for 4-5 hours, cool, wash with deionized water until neutral, and then vacuum dry at 60-100°C for 12 hours to obtain carboxylated carbon black; S21, dispersing carboxylated carbon black in anhydrous ethanol, ultrasonically dispersing for 30 minutes, adding γ-aminopropyltriethoxysilane thereto, stirring at 85-100° C. for 3-5 hours, centrifuging, washing with anhydrous ethanol three times, and drying at 60-100° C. to obtain silanized carbon black; S22, dispersing silanized carbon black in anhydrous ethanol, adding hyperbranched polyester, 3-glycidyloxypropyltrimethoxysilane and dibutyltin dilaurate thereto, reacting at 50° C. for 5-6 hours under nitrogen protection, and after completion, centrifuging, washing with anhydrous ethanol three times, and vacuum drying at 60-100° C. for 12 hours to obtain bifunctional carbon black; S3. Disperse the bifunctional carbon black in hydrochloric acid, ultrasonically disperse for 30 minutes, then add aniline and dodecylbenzenesulfonic acid, stir for 10 minutes, cool to 2°C, add ammonium persulfate, stir and react at a constant temperature of 2°C for 5-6 hours. After completion, centrifuge, wash with deionized water until neutral, and vacuum dry at 60-100°C for 12 hours to obtain an oxidized carbon black composite material.

2. The oxidized carbon black composite material according to claim 1, characterized in that: The particle size of the carbon black in S1 is 30 nm; the volume fraction of the concentrated nitric acid is 65%.

3. The oxidized carbon black composite material according to claim 1, characterized in that: The usage ratio of carbon black and concentrated nitric acid in S1 is 20g:200mL.

4. The oxidized carbon black composite material according to claim 1, characterized in that: The model of the hyperbranched polyester in S22 is Specialty Boltorn H2004.

5. The oxidized carbon black composite material according to claim 1, characterized in that: The usage ratio of carboxylated carbon black, anhydrous ethanol, and γ-aminopropyltriethoxysilane in S21 is 5 g:100 mL:2 g.

6. The oxidized carbon black composite material according to claim 1, characterized in that: The usage ratio of the silanized carbon black, anhydrous ethanol, hyperbranched polyester, 3-glycidyloxypropyltrimethoxysilane, and dibutyltin dilaurate described in S22 is 5g:100mL:10-15g:3-5g:0.1-0.2g.

7. The oxidized carbon black composite material according to claim 1, characterized in that: The molar concentration of the hydrochloric acid in S3 is 0.5 mol / L.

8. The oxidized carbon black composite material according to claim 1, characterized in that: The usage ratio of the bifunctional carbon black, hydrochloric acid, aniline, dodecylbenzenesulfonic acid, and ammonium persulfate in S3 is 10 g:100 mL:5-10 g:2-3 g:11.4-12.0 g.

9. Use of an oxidized carbon black composite material in coatings according to any one of claims 1 to 8, characterized in that: The following steps are involved: The coating's mass percentage formula is: 8% to 12% oxidized carbon black composite material, 8% to 12% acrylic resin, 0.5% dispersant, 0.5% bio-based dispersant, 1% 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2% silane coupling agent KH-460, and 76% pure water; Preparation method: Weigh the above raw materials according to mass percentage, add the oxidized carbon black composite material and pure water into a sand mill, then add a dispersant, a bio-based dispersant and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate thereto, disperse at 1500-3000 r / min for 1-2 hours, then add acrylic resin and silane coupling agent KH-460 thereto, continue stirring at 1500-3000 r / min for 2-4 hours to obtain a coating.

10. The use according to claim 9, characterized in that The solid content of the acrylic resin is 50%; the model of the dispersant is BYK-190; and the bio-based dispersant is alkyl polyglycoside APG06.

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