Conductive graphite emulsion and preparation method and application thereof

Abstract

The present invention provides a conductive graphite emulsion and a preparation method and application thereof. The conductive graphite emulsion comprises the following raw materials in percentage by mass: 12.0-35.0% of ultrafine graphite particles, 0.5-5.0% of conductive polymer additive, 1.0-5.0% of dispersant, 1.0-4.0% of debonding agent, and the balance is water; the molecular formula of the conductive polymer additive is. The present invention provides a conductive polymer additive with high conductivity and fast charge conduction speed, which has a significant effect on improving the conductive properties of the graphite emulsion; the conductive polymer additive can play the role of a skeleton in the graphite emulsion system, combining the dispersed ultrafine graphite particles into a network structure, so that a conductive path can be formed between the ultrafine graphite particles, thereby enabling the entire system to have excellent conductivity.

Description

Technical Field

[0001] The invention relates to the field of conductive material preparation, and in particular to a conductive graphite emulsion and a preparation method and application thereof. Background Art

[0002] Graphite emulsion (also called graphite slurry or graphite suspension) is a liquid composite material made by mixing fine graphite powder with appropriate dispersants and media. In addition to excellent conductivity and high thermal efficiency, graphite emulsion also has the advantages of low cost, light weight, high structure, non-toxicity and harmlessness. It is a functional coating with a large amount of use at present. It is widely used in batteries, electronic circuits, electromagnetic wave shielding, heating, antistatic, high temperature resistance and anticorrosion, marine antifouling, electroplating industry, and has broad application prospects. In addition, because conductive fillers have the advantages of wide sources, low price, good conductivity of coatings, safety and durability, convenient deep processing and molding, and resistance can be adjusted according to specific conditions, research on such graphite emulsion coatings has been relatively active for many years.

[0003] Chinese patent CN104064255A discloses a conductive graphite emulsion for preparing conductive fibers, a preparation method, and a method for preparing cellulose fibers using the graphite emulsion. The added conductive polymer additives are conventional polyacetylene, polypyrrole, polythiophene, poly(p-phenylene vinylene), polyaniline, polyphenylene sulfide, and poly(p-phenylene vinylene). They have poor conductivity, slow conductivity rate, and are very unstable and easily lose conductivity, making it difficult to form a stable and long-lasting conductive network in the system. Summary of the invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a conductive graphite emulsion to solve the problem that it is difficult to form a stable and long-lasting conductive network in the graphite emulsion system in the prior art. At the same time, the present invention will also provide a method for preparing a conductive graphite emulsion; in addition, the present invention will also provide an application of a conductive graphite emulsion.

[0005] In order to achieve the above-mentioned object and other related objects, the present invention provides the following technical solutions:

[0006] The first aspect of the present invention provides a conductive graphite emulsion, comprising the following raw materials in percentage by mass: 12.0-35.0% of ultrafine graphite particles, 0.5-5.0% of conductive polymer additive, 1.0-5.0% of dispersant, 1.0-4.0% of debonding agent, and the balance is water.

[0007] Furthermore, the ultrafine graphite particles include at least one of natural flake graphite, natural modified graphite, artificial graphite, and expanded graphite.

[0008] As conductive particles, when the content of ultrafine graphite particles is low, it is difficult to form an effective and stable conductive network structure, and it is also difficult to form a good conductive path, which makes the resistivity of the graphite emulsion relatively large, or even non-conductive. As the content of ultrafine graphite particles increases, a stable and effective conductive network is formed between the conductive particles, resulting in a significant decrease in the resistivity of the system, forming a sudden change in conductivity. Too many ultrafine graphite particles will also increase the viscosity of the graphite emulsion. Due to the small particle size, the ultrafine graphite particles will agglomerate and settle, and even increase the resistivity value, which reduces the conductivity of the graphite emulsion.

[0009] Furthermore, the mesh number of the graphite ultrafine particles is ≤12000 mesh, and the particle size of the graphite ultrafine particles should not be too small to avoid agglomeration caused by intermolecular forces.

[0010] Furthermore, the mesh size of the ultrafine graphite powder is 6000-10000 mesh.

[0011] Furthermore, the molecular formula of the conductive polymer additive is ;

[0012] Wherein, the polymerized unit P comprises a monomer I derived from the general formula (I):

[0013] (I);

[0014] Wherein, B1 is O, S or N;

[0015] B2 is N or C;

[0016] R1, R2 and R3 are each independently H, unsubstituted or substituted C1 to C 20 Alkyl or alkoxy, or unsubstituted or substituted C6 to C 20 Aryl, and q and w are each independently 0 or 1;

[0017] The terminal blocking group E comprises a monomer II derived from the general formula (II):

[0018] (II);

[0019] wherein R6, R7 and R8 are each independently H, unsubstituted or substituted C1 to C 20 Alkyl or alkoxy, or unsubstituted or substituted C6 to C 20 Aryl.

[0020] Furthermore, the monomer I of the general formula (I) comprises , , , , , A combination of one or more of the following, wherein R1, R2 and R3 are each independently H or a C1 to C3 alkyl or alkoxy group.

[0021] Furthermore, the monomer II of the general formula (II) comprises , , , , A combination of one or more of .

[0022] Furthermore, the weight ratio of the polymerized unit P to the terminal blocking group E is 100:1-20.

[0023] Furthermore, the molecular weight of the conductive polymer additive is between 2000-40000, preferably between 4000-12000.

[0024] Furthermore, the size of the conductive polymer additive is between 5-500 nm, preferably 10-100 nm.

[0025] The present invention provides a conductive polymer additive with high conductivity and fast charge conduction speed, which has a significant effect on improving the conductivity of graphite emulsion. In addition, the conductive polymer additive can play the role of a skeleton in the system, combining dispersed ultrafine graphite particles into a network structure, so that conductive paths can be formed between the ultrafine graphite particles, thereby making the entire system conductive.

[0026] The dosage of conductive polymer additives should be controlled within an appropriate range. When the dosage of conductive polymer additives is less than 0.5%, it is difficult to form a complete conductive network in the system and the conductivity of the system is poor. When the dosage of conductive polymer additives is higher than 5.0%, the viscosity of the system increases, which will affect the uniform dispersion, stability and wettability of ultrafine graphite particles and reduce the conductivity and mechanical properties of the graphite emulsion.

[0027] Furthermore, the dispersant includes at least one of sodium carboxymethyl cellulose, sodium hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, polyvinyl pyrrolidone, and polyvinyl alcohol.

[0028] Graphite ultrafine particles are hydrophobic substances. If you just stir the graphite ultrafine particles, you can't get a stable dispersion system. The dispersant can surround the graphite particles and make them hydrophilic, so that the graphite particles can be stably dispersed in water.

[0029] Furthermore, the dissolving agent is an alkaline substance or an anionic substance; preferably, ammonia water is cheap and has good effect.

[0030] The debonding agent can enhance the repulsive force between graphite particles, making them stably suspended in water without agglomeration or sedimentation, and the graphite particles are negatively charged in water with a pH of 9-10.

[0031] A second aspect of the present invention provides a method for preparing a conductive graphite emulsion, comprising the following steps:

[0032] S1. Add the conductive polymer additive and dispersant into water in proportion and stir evenly;

[0033] S2. Add the sieved ultrafine graphite particles in proportion and continue stirring;

[0034] S3. Add a dissolving agent during stirring and adjust the pH to 9-10;

[0035] S4, transferring the liquid obtained in step S3 into a ball mill or a sand mill for further grinding;

[0036] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner for ultrasonic treatment to obtain the conductive graphite emulsion.

[0037] Furthermore, in step S1 or S2, the stirring time is 0.5-2h, and the rotation speed is 600-1600rpm.

[0038] Further, in step S4, the ball milling time is 0.5-2h, and the grinding speed is 30-120rpm.

[0039] Furthermore, in step S5, the ultrasonic temperature is 20-30°C, the ultrasonic time is 30-120min, and the ultrasonic power is 500-800w.

[0040] The third aspect of the present invention provides an application of a conductive graphite emulsion, specifically, the application of the conductive graphite emulsion in the preparation of conductive coatings, conductive fibers, cathode ray tubes, electroforming, etc.

[0041] As described above, the conductive graphite emulsion and its preparation method and application of the present invention have the following beneficial effects:

[0042] 1. The present invention provides a conductive polymer additive with high conductivity and fast charge conduction speed, which has a significant effect on improving the conductive properties of graphite emulsion; the conductive polymer additive can play the role of a skeleton in the graphite emulsion system, combining the dispersed ultrafine graphite particles into a network structure, so that conductive paths can be formed between the ultrafine graphite particles, thereby enabling the entire system to have excellent conductivity.

[0043] 2. The present invention selects ultrafine graphite particles as conductive particles, which work synergistically with conductive polymer additives to form an effective and stable conductive network structure. The present invention adds a dispersant and a debonding agent to the system. The dispersant can enhance the hydrophilicity of the ultrafine graphite particles, and the debonding agent can enhance the repulsive force between the graphite particles, so that the graphite particles can be stably suspended in water without agglomeration or sedimentation, thereby making the formed conductive network structure more uniform, stable and complete. DETAILED DESCRIPTION

[0044] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0045] Example 1

[0046] 12 g of 30% polystyrene sulfonic acid aqueous solution, 253 g of deionized water, 2.8 g of 1% ferric sulfate and 2.2 g of sodium peroxodisulfate were added to the reactor. and 0.012g After reacting at room temperature, the mixture was treated with cation and anion exchange resins and filtered to obtain a conductive polymer additive A1.

[0047] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0048] S1, add 2% of the conductive polymer additive A1 prepared above and 2% sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0049] S2, adding 30% of ultrafine graphite particles sieved through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0050] S3. Add ammonia water during stirring to adjust the pH to 10;

[0051] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0052] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0053] Example 2

[0054] 12 g of 30% polystyrene sulfonic acid aqueous solution, 253 g of deionized water, 2.8 g of 1% ferric sulfate and 2.2 g of sodium peroxodisulfate were added to the reactor. and 0.12g After reacting at room temperature, it is treated with cation and anion exchange resins and filtered to obtain a conductive polymer additive A2.

[0055] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0056] S1, add 2% of the conductive polymer additive A2 prepared above and 2% sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0057] S2, adding 30% of ultrafine graphite particles sieved through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0058] S3. Add ammonia water during stirring to adjust the pH to 10;

[0059] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0060] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0061] Example 3

[0062] 12 g of 30% polystyrene sulfonic acid aqueous solution, 253 g of deionized water, 2.8 g of 1% ferric sulfate and 2.2 g of sodium peroxodisulfate were added to the reactor. and 0.24g After reacting at room temperature, the mixture was treated with cation and anion exchange resins and filtered to obtain a conductive polymer additive A3.

[0063] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0064] S1, add 2% of the conductive polymer additive A3 prepared above and 2% sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0065] S2, adding 30% of ultrafine graphite particles sieved through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0066] S3. Add ammonia water during stirring to adjust the pH to 10;

[0067] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0068] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0069] Example 4

[0070] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0071] S1, adding 0.5% of the conductive polymer additive A1 prepared in Example 1 and 2% of sodium carboxymethyl cellulose into water, and stirring at 800 rpm for 1 hour;

[0072] S2, adding 30% of ultrafine graphite particles sieved through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0073] S3. Add ammonia water during stirring to adjust the pH to 10;

[0074] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0075] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0076] Example 5

[0077] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0078] S1, add 5% prepared conductive polymer additive A1 and 2% sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0079] S2, adding 30% of ultrafine graphite particles sieved through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0080] S3. Add ammonia water during stirring to adjust the pH to 10;

[0081] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0082] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0083] Example 6

[0084] 12 g of 30% polystyrene sulfonic acid aqueous solution, 253 g of deionized water, 2.8 g of 1% ferric sulfate and 2.2 g of sodium peroxodisulfate were added to the reactor. and 0.12g After reacting at room temperature, the mixture was treated with cation and anion exchange resins and filtered to obtain a conductive polymer additive A4.

[0085] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0086] S1, add 3% of the conductive polymer additive A4 prepared above and 3% of sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0087] S2, adding 35% of ultrafine graphite particles passed through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0088] S3. Add ammonia water during stirring to adjust the pH to 9;

[0089] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0090] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0091] Example 7

[0092] 12 g of 30% polystyrene sulfonic acid aqueous solution, 253 g of deionized water, 2.8 g of 1% ferric sulfate and 2.2 g of sodium peroxodisulfate were added to the reactor. and 0.12g After reacting at room temperature, it was treated with cation and anion exchange resins and filtered to obtain a conductive polymer additive A5.

[0093] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0094] S1, add 1% of the conductive polymer additive A5 prepared above and 2% sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0095] S2, adding 12% of ultrafine graphite particles sieved through a 10000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0096] S3. Add ammonia water during stirring to adjust the pH to 10;

[0097] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0098] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0099] Comparative Example 1

[0100] A conductive graphite emulsion, the preparation method of which comprises the following steps:

[0101] S1, add 2% polythiophene and 2% sodium carboxymethyl cellulose into water, and stir at 800 rpm for 1 hour;

[0102] S2, adding 30% of ultrafine graphite particles sieved through a 6000 mesh sieve into the liquid of step S1, and stirring at 600 rpm for 30 min;

[0103] S3. Add ammonia water during stirring to adjust the pH to 10;

[0104] S4, transfer the liquid obtained in step S3 into a ball mill and grind at 60 rpm for 30 min;

[0105] S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner and perform ultrasonic cleaning at 600W for 30 minutes to obtain a conductive graphite emulsion.

[0106] The conductive graphite emulsions prepared in Examples 1-7 and Comparative Example 1 were subjected to performance testing, and the test results are shown in Table 1.

[0107] Table 1. Test results of conductive graphite emulsions of Examples 1-7 and Comparative Example 1

[0108]

[0109] In summary, the present invention provides a conductive polymer additive with high conductivity and fast charge conduction speed, which has a significant effect on improving the conductivity of graphite emulsion; the conductive polymer additive can play the role of a skeleton in the graphite emulsion system, combining the dispersed ultrafine graphite particles into a network structure, so that conductive paths can be formed between the ultrafine graphite particles, thereby enabling the entire system to have excellent conductivity. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0110] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A conductive graphite emulsion, characterized in that: The raw materials include the following mass percentages: 12.0-35.0% of ultrafine graphite particles, 0.5-5.0% of conductive polymer additive, 1.0-5.0% of dispersant, 1.0-4.0% of debonding agent, and the balance is water; Wherein, the molecular formula of the conductive polymer additive is , the weight ratio of the polymer unit P to the terminal blocking group E is 100:1-20, and the molecular weight of the conductive polymer additive is between 2000-40000; The polymerized unit P comprises a monomer I, wherein the monomer I comprises , , , At least one of, R1, R2 and R3 are each independently H or C1 to C3 alkyl or alkoxy; The terminal blocking group E comprises a monomer II, and the monomer II comprises , , , , At least one of .

2. The conductive graphite emulsion according to claim 1, characterized in that: The graphite ultrafine particles include at least one of natural flake graphite, natural modified graphite, artificial graphite and expanded graphite.

3. The conductive graphite emulsion according to claim 1, characterized in that: The dispersant includes at least one of sodium carboxymethyl cellulose, sodium hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose, polyvinyl pyrrolidone and polyvinyl alcohol.

4. The conductive graphite emulsion according to claim 1, characterized in that: The disintegrator is an alkaline substance or an anionic substance.

5. A method for preparing a conductive graphite emulsion as claimed in any one of claims 1 to 4, characterized in that: The steps include: S1. Add the conductive polymer additive and dispersant into water in proportion and stir evenly; S2. Add the sieved ultrafine graphite particles in proportion and continue stirring; S3. Add a dissolving agent during stirring and adjust the pH to 9-10; S4, transferring the liquid obtained in step S3 into a ball mill or a sand mill for further grinding; S5. Transfer the liquid obtained in step S4 to an ultrasonic cleaner for ultrasonic treatment to obtain the conductive graphite emulsion.

6. An application of the conductive graphite emulsion according to any one of claims 1 to 4, characterized in that: Applications in the preparation of conductive coatings, conductive fibers, cathode ray tubes, and electroforming.

Images