A branched dispersant and its preparation method and application

Abstract

The present invention discloses a branched dispersant, its preparation method, and application, belonging to the field of materials technology. The branched dispersant comprises a core and chain arms. The core is a polymer containing amino groups. The chain arms include chain arms containing alkyl segments and chain arms containing polyether segments and / or carboxyl segments. The chain arms are covalently bonded to the core via amino groups on the core. This dispersant has excellent dispersing properties and can be widely used in the dispersion of carbon materials, particularly in the dispersion of positive electrode slurries. It exhibits excellent dispersion, viscosity reduction, and slurry stability.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a branched dispersant and a preparation method and application thereof. Background Art

[0002] In recent years, with the development of the new energy industry, carbon materials such as carbon nanotubes, graphene, and conductive carbon black have been widely used. Due to their unique particle structure and surface morphology, these carbon materials, when prepared without a dispersant or with traditional polyvinyl pyrrolidone dispersants, can suffer from problems such as poor or ineffective dispersion, high viscosity, and short storage life in the resulting slurry, thus affecting subsequent use. Summary of the Invention

[0003] In response to the above problems, the present invention provides a branched dispersant, which has excellent dispersing properties and can be widely used in the dispersion of carbon materials, especially suitable for the dispersion of positive electrode slurries. It has the advantages of good dispersion and viscosity reduction, good slurry stability, etc.

[0004] The present invention provides a branched dispersant, comprising a core and chain arms, wherein the core is a polymer having an amino group, the chain arms include chain arms having an alkyl segment, and chain arms having a polyether segment and / or a carboxyl segment, and the chain arms are covalently connected to the core via amino groups on the core.

[0005] In some embodiments, the number average molecular weight of the core is 500-10,000, preferably 600-10,000; further, the number average molecular weight of the core is 700-3,000, and further, the number average molecular weight of the core is 800-2,000, for example, 800, 2,000.

[0006] In some embodiments, the alkyl segment has a structural fragment represented by the following formula (I):

[0007]

[0008]

[0009] In formula (I), z is an integer of 4-24, preferably an integer of 12-18, for example, 12 or 18, more preferably 18.

[0010] In some embodiments, the chain arms having polyether segments have a number average molecular weight of 300-3000, preferably 1500-2500, for example 2000.

[0011] In some embodiments, the polyether segment has a structural fragment represented by the following formula (II):

[0012]

[0013] In formula (II), R1 is H or CH3, R2 is a C1-C8 alkyl group, and y is an integer of 8-70, preferably 35-46.

[0014] In some embodiments, the carboxyl segment has a structural fragment represented by the following formula (III):

[0015]

[0016] In formula (III), R3 is -CH2-, R4 is H or CH3; R3 is H or CH3, R4 is a C1-C8 alkyl group, and x is an integer of 8-70, preferably 35-46.

[0017] In some embodiments, the number average molecular weight of the chain arm having a carboxyl segment is 300-3000, preferably 500-2000.

[0018] In some embodiments, the covalent bond is an amide bond or a CN bond.

[0019] In some embodiments, the core is selected from: polyethyleneimine; preferably branched polyethyleneimine, such as: Lupasol series polyethyleneimine, Epomin series polyethyleneimine, further preferably: Lupasol FG, Lupasol PR8515.

[0020] In some embodiments, the chain arm having an alkyl segment is selected from one or more of alkyl acrylates, fatty acid methyl esters, and monofunctional aliphatic isocyanates; preferably, the alkyl segment is selected from C4H9, C6H 13 , C8H 17 , C 12 H 25 , C 16 H 33 , C 18 H 37 , C 20 H 41 , C 22 H 45 , C 24 H 49 More preferably, at least one of methyl stearate, octadecyl acrylate and lauryl acrylate, for example, methyl stearate and / or octadecyl acrylate.

[0021] In some embodiments, the chain arm having a polyether segment is selected from: a blocked polyether (meth)acrylate or an intermediate obtained by ring-opening maleic anhydride with a monofunctional blocked polyether containing a hydroxyl group or an amino group at the end. Preferably, the polyether segment is selected from: at least one of polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, and poly(ethylene oxide-propylene oxide) monomethyl ether; preferably, at least one of polyethylene glycol 480 monomethyl ether acrylate, polyethylene glycol 400 monomethyl ether methacrylate, the reaction product of maleic anhydride and Genamin M41 / 2000, and the reaction product of maleic anhydride and Polyglykol B11 / 30.

[0022] In some embodiments, the chain arm having a carboxyl segment is selected from acrylic acid, and an intermediate obtained by ring-opening maleic anhydride with a monofunctional end-capped polyether containing a hydroxyl group or an amino group at the end.

[0023] In some embodiments, the amount of the chain arms having alkyl segments is 1% to 50% of the total mass of the branched dispersant, preferably 19% to 50%.

[0024] In some embodiments, the amount of the chain arms having polyether segments is 1%-60% of the total mass of the branched dispersant, preferably 20%-60%, more preferably 40%-60%, for example 45%-60%.

[0025] In some embodiments, the amount of the chain arms having carboxyl segments is 1%-60% of the total mass of the branched dispersant, preferably 1%-20%, for example, 2%-11%.

[0026] On the other hand, the present invention also discloses a method for preparing the branched dispersant, comprising the following steps:

[0027] Chain arm mixing: mixing a chain arm having a polyether segment and / or a carboxyl segment with a chain arm raw material having an alkyl segment in a solvent to obtain a chain arm mixture;

[0028] Grafting: adding the core to the mixture of the chain arms, reacting, so that the chain arms are connected to the core through amino groups on the core by covalent bonds, thereby obtaining the product.

[0029] In some embodiments, the solvent is selected from at least one of water, alcohol solvents, ester solvents, ketone solvents, aromatic hydrocarbon solvents, N-methylpyrrolidone, and N,N-dimethylformamide; for example, N-methylpyrrolidone.

[0030] In some embodiments, the amount of the solvent is 1-10 times, preferably 1-5 times, and more preferably 1-2 times the total mass of the chain arm.

[0031] In some embodiments, in the grafting step, the reaction temperature is 40-120°C, preferably 60-70°C.

[0032] In some embodiments, in the grafting step, the reaction time is 1-8 hours, preferably 4-7 hours, for example 6 hours.

[0033] In some embodiments, before the chain arm mixing step, a chain arm preparation step is also included, and the chain arm preparation step is: dissolving maleic anhydride in a solvent, and then adding a monofunctional end-capped polyether containing a hydroxyl group or an amino group at the end, and reacting to obtain a chain arm raw material having a polyether segment and a carboxyl segment.

[0034] In some embodiments, the molar ratio of the hydroxyl group or amine group to the maleic anhydride is 1:1.

[0035] In some embodiments, the reaction temperature is 20-90°C, preferably 20-40°C.

[0036] In some embodiments, the reaction time is 0.5-4 hours, preferably 0.5-2 hours, for example 1 hour.

[0037] On the other hand, the present invention also discloses the use of the above-mentioned branched dispersant in dispersing carbon materials.

[0038] In some embodiments, the carbon material is selected from at least one of pigment carbon black, conductive carbon black, carbon nanotubes, graphene, and carbon-coated materials.

[0039] On the other hand, the present invention also discloses a carbon material dispersion liquid, comprising: a carbon material and the above-mentioned branched dispersant.

[0040] In some embodiments, the carbon material is selected from at least one of pigment carbon black, conductive carbon black, carbon nanotubes, graphene, and carbon-coated materials.

[0041] In some embodiments, the carbon material dispersion includes lithium iron phosphate, conductive carbon black, PVDF and the branched dispersant.

[0042] For example, the carbon material dispersion includes 59.43 wt % of lithium iron phosphate, 0.427 wt % of conductive carbon black, 1.098 wt % of PVDF and 0.0488 wt % of the branched dispersant.

[0043] symbol Indicates the site where the fragment is connected to other groups.

[0044] The above-mentioned "hyperbranched polyethyleneimine" (HPEI) is a highly branched repeating unit polymer composed of ethylenediamine groups. The end of its branch chain contains a large number of amino groups such as primary amino groups, secondary amino groups and tertiary amino groups, which can be used as the connection basis of chain arms.

[0045] The above-mentioned "alkyl acrylate" is an ester obtained from acrylic acid and an alkyl group, such as octadecyl acrylate, lauryl acrylate, and the like.

[0046] The above-mentioned "fatty acid methyl ester" is an ester formed by an esterification reaction between a long-chain fatty acid and methanol, such as methyl stearate, methyl laurate, etc.

[0047] The above-mentioned “blocked polyether (meth)acrylate” is a polymer obtained by blocking a polyether with a (meth)acrylate.

[0048] The aforementioned "monofunctional terminated polyether containing a hydroxyl group or an amine group at the end" refers to a polyether having one terminal hydroxyl group terminated by a capping agent, such as polyethylene glycol monomethyl ether. "Monofunctional" refers to a single functional group, such as a polyether segment containing only one amine group.

[0049] The above-mentioned "carbon-coated materials" are materials formed by forming a carbon layer on the surface of the material through a carbon-forming agent, such as lithium iron phosphate, lithium manganese iron phosphate, etc.

[0050] The above-mentioned “PVDF” is polyvinylidene fluoride (PVDF), which is obtained by polymerizing vinylidene fluoride monomers.

[0051] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0052] The reagents and raw materials used in the present invention are commercially available.

[0053] The positive progress effect of the present invention is:

[0054] The branched dispersant of the present invention has a polymer having an amino group as a core. The amino group is used as a reactive group to covalently link chain arms having an alkyl chain segment and chain arms having a polyether chain segment and / or a carboxyl chain segment. The chain arms having the polyether chain segment and / or the carboxyl chain segment can stabilize the slurry by providing steric hindrance and / or electrostatic repulsion, while the chain arms having the alkyl chain segment can be surface-adsorbed with dispersed substances such as carbon materials, acting as anchors. The synergistic effect provides a good dispersing effect. This provides the branched dispersant with advantages such as good dispersing effect and high dispersion stability.

[0055] The preparation method of the branched dispersant of the present invention has the advantages of simple and stable process and is suitable for industrial production.

[0056] Dispersions obtained using the branched dispersant of the present invention, such as carbon material dispersions and cathode slurries, exhibit excellent dispersion and viscosity reduction, as well as good slurry stability. This can improve dispersion efficiency, increase production capacity, and reduce energy consumption during the dispersion process in future production processes. DETAILED DESCRIPTION

[0057] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0058] Lupasol PR8515, purchased from BASF, is a branched polyethyleneimine with a number-average molecular weight of ∼2000;

[0059] Lupasol FG, purchased from BASF, is a branched polyethyleneimine with a number-average molecular weight of ∼800;

[0060] Polyethylene glycol 480 monomethyl ether acrylate, i.e. polyethylene glycol monomethyl ether acrylate (Mn480) (CAS: 32171-39-4), was purchased from Shanghai Titan Technology Co., Ltd., with a number average molecular weight of 480;

[0061] Polyethylene glycol 400 monomethyl ether methacrylate, also known as poly(ethylene glycol) methacrylate (CAS: 25736-86-1), was purchased from Shanghai Titan Technology Co., Ltd., with a number average molecular weight of approximately 400;

[0062] Genamin M41 / 2000, purchased from Clariant, is a polyether monoamine with primary amine groups and a number average molecular weight of 2000;

[0063] Polyglykol B11 / 30, purchased from Clariant, is a polyether with hydroxyl groups and a number average molecular weight of 1000;

[0064] PVP K30 was purchased from BASF and is polyvinyl pyrrolidone with a number average molecular weight of about 30,000.

[0065] 1. Preparation of branched dispersant AG

[0066] For the sake of convenience, the core of the polymer having an amino group is referred to as core A, the chain arm having a polyether segment is referred to as chain arm B, the chain arm having a carboxyl segment is referred to as chain arm C, and the chain arm having an alkyl segment is referred to as chain arm D.

[0067] According to Table 1 below, chain arm B, linker arm C, linker arm D, and 63.1 g of N-methylpyrrolidone (solvent) were added to a 250 ml four-necked round-bottom flask. A condenser and thermometer were installed, and a mechanical stirrer was started. Core A was slowly added. After addition, the temperature was raised to 70°C and the reaction was continued at this temperature for 6 hours. Branched dispersant AH was obtained without purification.

[0068] Table 1. Raw material formula

[0069]

[0070] 2. Preparation of branched dispersant I

[0071] To a 100ml four-necked round-bottom flask, add 0.55g of maleic anhydride and 29g of N-methylpyrrolidone as the reaction solvent. Install a condenser and thermometer, and start a mechanical stirrer. Slowly add 11.22g of Genamin M41 / 2000, controlling the temperature below 40°C. Maintain the temperature below 40°C after addition is complete and allow the reaction to proceed for 1 hour. This yields a polymer having the structure of Formula IV, which possesses both carboxylic acid and polyether functional groups, fulfilling the functions of both chain arms B and C.

[0072]

[0073] R1 is H or CH3, y=35-46.

[0074] After the insulation is completed, 11.26 g of octadecyl acrylate (chain arm D) is added and mixed evenly, and then 6 g of Lupasol PR8515 (core A) is slowly added. After the addition is complete, the temperature is raised to 60° C. and the insulation reaction is continued for 6 hours to obtain branched dispersant I.

[0075] 3. Preparation of branched dispersant J

[0076] To a 100ml four-necked round-bottom flask, add 1.0g of maleic anhydride and 28g of N-methylpyrrolidone as the reaction solvent. Install a condenser and thermometer, and start a mechanical stirrer. Slowly add 10.2g of Polyglykol B11 / 30. After addition, maintain the temperature at no higher than 90°C and allow the reaction to continue for 1 hour. This yields a polymer with the structure shown in Formula V, which possesses both carboxylic acid and polyether functional groups, fulfilling the functions of both chain arms B and C.

[0077]

[0078] R1 is H or CH3, y=35-46.

[0079] After the insulation is completed, 10.93 g of octadecyl acrylate (chain arm D) is added and mixed evenly, and then 6 g of Lupasol PR8515 (core A) is slowly added. After the addition is complete, the temperature is raised to 60°C and the insulation reaction is continued for 6 hours to obtain branched dispersant J.

[0080] Comparative Example

[0081] 1. Preparation of comparative dispersant A

[0082] To a 100ml four-necked round-bottom flask, add 20.0g of polyethylene glycol 480 monomethyl ether acrylate, 8.66g of acrylic acid, and 34.66g of N-methylpyrrolidone. Install a condenser and thermometer, and start a mechanical stirrer. Slowly add 6g of Lupasol 8515. After addition, raise the temperature to 70°C and continue the reaction at this temperature for 6 hours. This yields a product without the chain-mounted arm D, which is Comparative Dispersant A.

[0083] 2. Preparation of comparative dispersant B

[0084] Add 0.55g of maleic anhydride and 29g of N-methylpyrrolidone to a 100ml four-necked round-bottom flask. Install a condenser and thermometer, then start a mechanical stirrer. Heat to 100°C and slowly add 11.22g of Genamin M41 / 2000. Keep the mixture warm for 1 hour.

[0085] After the insulator was complete, 11.26 g of octadecyl acrylate was added and mixed thoroughly. Then, 6 g of Lupasol PR8515 was slowly added. After the addition was complete, the temperature was raised to 60°C and the reaction was continued for 6 hours. After cooling and discharging, the product separated into two phases and could not be used as a dispersant.

[0086] Effect Experiment Example

[0087] This experimental example takes the NMP solvent system as an example to illustrate the application effect of the branched dispersant AJ obtained in the example in carbon materials.

[0088] The experiment was conducted using polyvinyl pyrrolidone (PVP K30) commonly used in the market, comparative dispersant A prepared in a comparative example, and a control without adding a dispersant.

[0089] Specifically, based on the mass basis, the lithium iron phosphate addition amount was 59.43%, and 0.0488% of the above-mentioned branched dispersants AJ, comparative dispersant A, 0.427% conductive carbon black and 1.098% PVDF were added respectively, and the mixture was shaken for 4 hours. A blank group (no dispersant added) and a comparative sample PVP K30 group were set as controls.

[0090] After maintaining the temperature at 25°C, the rotational viscosity was tested using a Brookfield rotational viscometer with a #64 rotor at 30 rpm for 3 minutes. The viscosity was then read. The viscosity was then tested again after 2 and 24 hours of stabilization to assess stability.

[0091] The results are shown in the following table.

[0092] Table 2. Dispersion properties of various dispersants

[0093]

[0094] The above results show that the branched dispersants A and J prepared in the present invention all have discharge viscosities lower than those of PVP K30, demonstrating superior dispersibility. Dispersants AE and IJ exhibit particularly excellent performance. Branched dispersant F exhibits slightly reduced dispersibility due to the addition of lauryl acrylate as chain arm D. Branched dispersants G and H also exhibit slightly reduced dispersibility due to the absence of polyether or carboxyl segments, as they lack chain arms B or C. However, their discharge viscosities are superior to those of PVP K30.

[0095] The blank experiment shows that without adding dispersant, the viscosity of the discharged slurry has reached 16,000, indicating that when the viscosity of the discharged slurry is too high, the increase in its viscosity is not large.

Claims

1. A branched dispersant, characterized in that: The invention comprises a core and chain arms, wherein the core is a polymer having an amino group, the chain arms include chain arms having an alkyl segment, and chain arms having a polyether segment and a carboxyl segment, and the chain arms are covalently connected to the core through an amino group on the core; The number average molecular weight of the core is 800-2000; The alkyl segment has a structural fragment shown in the following formula (I): In formula (I), z is 18; The number average molecular weight of the chain arm having the polyether segment is 300-3000; The polyether segment has a structural fragment shown in the following formula (II): In formula (II), R1 is H or CH3, R2 is a C1-C8 alkyl group, and y is an integer of 8-70; The number average molecular weight of the chain arm having the carboxyl segment is 300-3000; The amount of the chain arms with alkyl chain segments is 19%-50% of the total mass of the branched dispersant; the amount of the chain arms with polyether chain segments is 40%-60% of the total mass of the branched dispersant; and the amount of the chain arms with carboxyl chain segments is 2%-11% of the total mass of the branched dispersant.

2. The branched dispersant according to claim 1, wherein Meet one or more of the following conditions: (1) The number average molecular weight of the core is 800 or 2000; (2) the number average molecular weight of the chain arm having the polyether segment is 1500-2500; (3) In formula (II), y is an integer from 35 to 46; (4) The carboxyl segment has a structural fragment represented by the following formula (III): In formula (III), R3 is -CH2-, R4 is H or CH3; R1 is H or CH3, R2 is a C1-C8 alkyl group, and x is an integer from 8 to 70; (5) The number average molecular weight of the chain arm having a carboxyl segment is 500 to 2000; (6) The covalent bond is an amide bond or a CN bond.

3. The branched dispersant according to claim 2, wherein Meet one or more of the following conditions: (1) The number average molecular weight of the chain arm having the polyether segment is 2000; (2) In formula (III), x is an integer of 35-46.

4. The branched dispersant according to claim 2, wherein Meet one or more of the following conditions: (1) The core is selected from: branched polyethyleneimine; (2) The chain arm having an alkyl chain segment is selected from one or more of alkyl acrylates, fatty acid methyl esters, and monofunctional aliphatic isocyanates; (3) The chain arms having polyether segments are selected from: end-capped polyether (meth)acrylates or intermediates obtained by ring-opening maleic anhydride with a monofunctional end-capped polyether containing a hydroxyl group or an amino group at the end; (4) The chain arms having carboxyl segments are selected from acrylic acid and intermediates obtained by ring-opening maleic anhydride with a monofunctional end-capped polyether containing a hydroxyl group or an amino group at the end.

5. The branched dispersant according to claim 4, wherein Meet one or more of the following conditions: (1) The core is selected from: Lupasol series polyethyleneimine or Epomin series polyethyleneimine; (2) the chain arm having an alkyl segment is selected from: methyl stearate and / or octadecyl acrylate; (3) The polyether segment is selected from at least one of polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, and poly(ethylene oxide-propylene oxide) monomethyl ether.

6. The branched dispersant according to claim 4, wherein Meet one or more of the following conditions: (1) The core is selected from: Lupasol FG or Lupasol PR8515; (2) The polyether segment is selected from at least one of polyethylene glycol 480 monomethyl ether acrylate, polyethylene glycol 400 monomethyl ether methacrylate, the reaction product of maleic anhydride and Genamin M41 / 2000, and the reaction product of maleic anhydride and Polyglykol B11 / 30.

7. The branched dispersant according to claim 1, wherein The amount of the chain arms having polyether segments is 45%-60% of the total mass of the branched dispersant.

8. The method for preparing the branched dispersant according to any one of claims 1 to 7, characterized in that: The following steps are involved: Chain arm mixing: mixing a chain arm having a polyether segment and a carboxyl segment with a chain arm raw material having an alkyl segment in a solvent to obtain a chain arm mixture; Grafting: adding the core to the mixture of the chain arms, reacting, so that the chain arms are connected to the core through amino groups on the core by covalent bonds, thereby obtaining the product.

9. The method for preparing a branched dispersant according to claim 8, wherein Meet one or more of the following conditions: (1) The solvent is selected from at least one of water, alcohol solvents, ester solvents, ketone solvents, aromatic hydrocarbon solvents, N-methylpyrrolidone, and N,N-dimethylformamide; (2) The amount of the solvent is 1-10 times the total mass of the chain arm; (3) In the grafting step, the reaction temperature is 40-120°C; (4) In the grafting step, the reaction time is 1-8 hours.

10. The method for preparing a branched dispersant according to claim 9, wherein Meet one or more of the following conditions: (1) The solvent is N-methylpyrrolidone; (2) The amount of the solvent is 1-5 times the total mass of the chain arm; (3) In the grafting step, the reaction temperature is 60-70°C; (4) In the grafting step, the reaction time is 4-7 hours.

11. The method for preparing a branched dispersant according to claim 10, wherein: Meet one or more of the following conditions: (1) The amount of the solvent is 1-2 times the total mass of the chain arm; (2) In the grafting step, the reaction time is 6 hours.

12. The method for preparing a branched dispersant according to claim 8, wherein: Before the chain arm mixing step, a chain arm preparation step is also included, which is: dissolving maleic anhydride in a solvent, then adding a monofunctional end-capped polyether containing a hydroxyl group or an amino group at the end, and reacting to obtain a chain arm raw material having a polyether segment and a carboxyl segment.

13. The method for preparing a branched dispersant according to claim 12, wherein: The molar ratio of the hydroxyl group or amino group to the maleic anhydride is 1:

1.

14. The method for preparing a branched dispersant according to claim 13, wherein: The reaction temperature is 20-90° C.; and / or the reaction time is 0.5-4 hours.

15. The method for preparing a branched dispersant according to claim 14, wherein: The reaction temperature is 20-40° C.; and / or the reaction time is 0.5-2 hours.

16. The method for preparing a branched dispersant according to claim 15, wherein: The reaction time is 1 hour.

17. Use of the branched dispersant according to any one of claims 1 to 7 in dispersing carbon materials.

18. The use according to claim 17, characterized in that The carbon material is selected from at least one of pigment carbon black, conductive carbon black, carbon nanotubes, graphene and carbon coating materials.

19. A carbon material dispersion, characterized in that: The invention comprises: a carbon material and the branched dispersant according to any one of claims 1 to 7.

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