Hydrogenated nitrile latex, method for producing same, and carbon material dispersion

Abstract

The present invention relates to a hydrogenated nitrile-based latex having a low residual inorganic substance content and having low molecular weight characteristics, a method for producing the same, and a carbon material dispersion comprising the same, and provides: a hydrogenated nitrile-based latex containing a monomer that satisfies formula (1): Ru + Pd + Rhlt; 60 ppm, formula (2): Ca + Mg + Allt; the present invention relates to a hydrogenated nitrile latex containing a hydrogenated nitrile copolymer having a weight average molecular weight of 10,000 g / mol or more and less than 8,000 g / mol, a solvent displacement viscosity of 200 ppm, a solvent displacement viscosity of 10 cp to 150 cp, and a weight average molecular weight of 10,000 g / mol or more, a method for producing the same, and a carbon material dispersion.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2024-0032865, filed on March 7, 2024, and Korean Patent Application No. 10-2024-0034630, filed on March 12, 2024, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention relates to hydrogenated nitrile latexes with low residual inorganic content, low viscosity and low molecular weight, as well as their manufacturing methods and carbon material dispersions. Background Technology

[0004] Generally, nitrile rubber refers to polymers copolymerized from olefinically unsaturated nitrile monomers such as acrylonitrile and conjugated diene monomers such as 1,3-butadiene. Hydrogenated nitrile rubber, produced by the hydrogenation reaction of nitrile rubber, is a special rubber exhibiting excellent heat resistance, ozone resistance, chemical resistance, and oil resistance. It is widely used in various applications such as synchronous belts, seals, hoses, diaphragms, and rollers.

[0005] Currently, commercially available hydrogenated nitrile rubber is manufactured using the following method: nitrile rubber is dissolved in a solvent and reacted with gaseous hydrogen under high temperature and pressure in the presence of a noble metal catalyst, thereby hydrogenating the double bonds in the nitrile rubber. The used catalyst and solvent are then removed. This method is quite complex and expensive due to the use of high-pressure reactors and noble metal catalysts, the environmental problems caused by solvent use, and the limitation of using only large quantities of rubber.

[0006] Furthermore, in methods using precious metal catalysts, attempts are made to use as few expensive catalysts as possible due to their high cost. However, using a small amount of catalyst leads to a decrease in the hydrogenation rate and an increase in the molecular weight of the prepared hydrogenated nitrile rubber, which reduces dispersibility and increases viscosity. On the other hand, using a large amount of catalyst results in a large amount of residual metal in the final hydrogenated nitrile rubber, which increases viscosity due to the residual metal and requires high cost to remove.

[0007] An alternative approach involves hydrogenating nitrile rubbers in latex form with diimides, offering advantages not only in terms of safety but also in terms of economy and environment compared to typical methods that involve reactions in high-pressure reactors using hydrogen, solvents, and expensive precious metal catalysts. However, despite these multiple benefits, commercialization has not yet been achieved due to gel formation caused by side reactions during hydrogenation. Furthermore, crosslinking occurs during and after hydrogenation in the polymerization, drying, and storage stages, negatively impacting the properties of the final hydrogenated nitrile latex.

[0008] Therefore, there is a need for hydrogenated nitrile latexes with low molecular weight, high degree of hydrogenation, and low residual metal content, as well as their manufacturing methods.

[0009] [Related Technical Documents]

[0010] [Patent Literature]

[0011] (Patent Document 1) KR10-2021-0035088A (2021.03.31) Summary of the Invention

[0012] Technical issues

[0013] One aspect of the present invention provides a hydrogenated nitrile latex comprising a hydrogenated nitrile copolymer having low residual metal content and low viscosity.

[0014] Another aspect of the present invention provides a method for manufacturing hydrogenated nitrile latex.

[0015] In addition, another aspect of the present invention provides a carbon material dispersion comprising the above-described hydrogenated nitrile copolymer.

[0016] Technical solution

[0017] To address the aforementioned issues, this invention provides hydrogenated nitrile latex, a method for manufacturing the same, and a carbon material dispersion.

[0018] (1) According to one aspect of the present invention, a hydrogenated nitrile latex is provided, comprising a hydrogenated nitrile copolymer satisfying the following formulas (1) and (2), having a solvent displacement viscosity of 10 cp to 150 cp and a weight-average molecular weight of 10,000 g / mol or more and less than 80,000 g / mol, wherein the solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C) on a solution in which the hydrogenated nitrile copolymer is dissolved at 16% by weight in an amide dispersion medium. Equation (1): Ru + Pd + Rh < 60ppm Equation (2): Ca + Mg + Al < 200 ppm In equations (1) and (2) above, The contents of Ru, Pd, Rh, Ca, Mg and Al in the hydrogenated nitrile copolymer were determined by ICP-OES (RF power 1300W, plasma gas flow rate 15L / min).

[0019] (2) The present invention provides a hydrogenated nitrile latex according to (1) above, wherein, in the above formula (1), Ru+Pd+Rh is less than 50ppm, and in the above formula (2), Ca+Mg+Al is less than 200ppm.

[0020] (3) The present invention provides a hydrogenated nitrile latex according to (1) or (2) above, wherein, in formula (1) above, Ru+Pd+Rh is less than 50 ppm, and in formula (2) above, Ca+Mg+Al is less than 100 ppm.

[0021] (4) The present invention provides a hydrogenated nitrile latex according to any one of (1) to (3) above, wherein the viscosity of the hydrogenated nitrile copolymer is 10 cp to 100 cp.

[0022] (5) The present invention provides a hydrogenated nitrile latex according to any one of (1) to (4) above, wherein the weight-average molecular weight of the hydrogenated nitrile copolymer is from 15,000 g / mol to 55,000 g / mol.

[0023] (6) The present invention provides a hydrogenated nitrile latex according to any one of (1) to (5) above, wherein the degree of hydrogenation of the hydrogenated nitrile copolymer is 60% or more.

[0024] (7) The present invention provides a hydrogenated nitrile latex according to any one of (1) to (6) above, wherein the hydrogenated nitrile copolymer comprises an olefinically unsaturated nitrile monomer unit and a hydrogenated conjugated diene monomer unit.

[0025] (8) The present invention provides a hydrogenated nitrile latex according to (7) above, wherein the weight ratio of the olefinically unsaturated nitrile monomer unit to the hydrogenated conjugated diene monomer unit is 1:99 to 50:50.

[0026] (9) The present invention provides a hydrogenated nitrile latex according to (7) or (8) above, wherein the hydrogenated nitrile copolymer further comprises conjugated diene monomer units.

[0027] (10) According to another aspect of the present invention, a method for manufacturing a hydrogenated nitrile latex comprising any one of (1) to (10) above, the method comprising: polymerizing a monomer mixture comprising a conjugated diene monomer and an olefinically unsaturated nitrile monomer in the presence of an emulsifier to prepare a nitrile copolymer (S1); hydrogenating the nitrile copolymer to prepare a hydrogenated nitrile copolymer (S2); and subjecting the hydrogenated nitrile copolymer to an ozone decomposition reaction (S3), wherein step (S3) is carried out by bubbling a mixture of air and ozone into the hydrogenated nitrile copolymer, and the mixture of air and ozone comprises more than 0.1 mol and less than 0.5 mol of ozone.

[0028] (11) The present invention provides the method according to (10) above, wherein the hydrogenation in step (S2) is carried out in the presence of an oxidant and a reducing agent.

[0029] (12) The present invention provides the method according to (10) or (11) above, wherein the ozone decomposition reaction in step (S3) is carried out at a temperature of 0°C to 75°C.

[0030] (13) According to another aspect of the present invention, a carbon material dispersion is provided, comprising a carbon material, a dispersion medium, and a hydrogenated nitrile copolymer, wherein the hydrogenated nitrile copolymer satisfies the following formulas (1) and (2), has a solvent displacement viscosity of 10 cp to 150 cp, and a weight-average molecular weight of 10,000 g / mol or more and less than 80,000 g / mol, wherein the solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C) on a solution in which the hydrogenated nitrile copolymer is dissolved at 16% by weight in an amide dispersion medium. Equation (1): Ru + Pd + Rh < 60ppm Equation (2): Ca + Mg + Al < 200 ppm In equations (1) and (2) above, The contents of Ru, Pd, Rh, Ca, Mg and Al in the hydrogenated nitrile copolymer were determined by ICP-OES (RF power 1300W, plasma gas flow rate 15L / min).

[0031] (14) The present invention provides a carbon material dispersion according to (13) above, wherein the viscosity of the carbon material dispersion is 1000 cp or more and less than 15000 cp.

[0032] (15) The present invention provides a carbon material dispersion according to (13) or (14) above, wherein the carbon material is at least one selected from carbon black, Ketjen black, fullerene, graphene, carbon nanotubes, carbon black and graphite.

[0033] Beneficial effects

[0034] The hydrogenated nitrile latex according to the present invention has a low residual inorganic content and a low viscosity, thereby exhibiting excellent dispersibility.

[0035] According to the method for manufacturing hydrogenated nitrile latex of the present invention, by hydrogenating without a precious metal catalyst and performing an ozone decomposition reaction with controlled ozone content, it is possible to manufacture low molecular weight and low viscosity hydrogenated nitrile latex with extremely low residual metal content and excellent degree of hydrogenation.

[0036] The carbon material dispersion according to the present invention comprises a hydrogenated nitrile copolymer with low molecular weight, low viscosity and extremely low metal residue content, and therefore can have excellent dispersibility. Detailed Implementation

[0037] The invention will be described in detail below to aid in understanding it.

[0038] It should be understood that the words or terms used in the specification and claims of this invention should not be construed as having meanings limited to those defined in common dictionaries. It will be further understood that, based on the principle that the inventors may appropriately define the meanings of words or terms to best interpret the invention, the words or terms should be interpreted as having meanings consistent with their meanings in the relevant field and in the context of the technical concept of the invention.

[0039] Terminology Definition

[0040] As used herein, the term "latex" can refer to a polymer or copolymer polymerized by polymerization that exists in a form dispersed in water or a solvent. As a specific example, it can refer to particles of a rubbery polymer or particles of a rubbery copolymer polymerized by polymerization that exist in a colloidal state dispersed in a solvent, and can also be referred to as an "emulsion".

[0041] Measurement methods

[0042] Here, an ICP-OES apparatus was used with an RF power of 1300 W and a plasma gas flow rate of 15 L / min to determine the content of residual metal ions in the hydrogenated nitrile copolymer. The detection limit was 60 ppm; a residual metal ion content less than 60 ppm was interpreted as the absence of residual metal ions. The hydrogenated nitrile copolymer latex was then dried in a vacuum oven at 60 °C for 24 hours to obtain the hydrogenated nitrile copolymer in the latex, thus preparing the sample for ICP-OES determination. Then, 0.1 g of the hydrogenated nitrile copolymer was diluted in 15 mL of hydrofluoric acid, and heat-treated from room temperature (23 ± 5 °C) to 250 °C for 90 minutes, followed by holding at that temperature for 60 minutes.

[0043] Here, the solvent displacement viscosity of the hydrogenated nitrile copolymer is determined using a Brookfield viscometer (#63 rotor, 25°C) with a dispersion containing 16% by weight of the hydrogenated nitrile copolymer as a sample. The dispersion is a mixture of the hydrogenated nitrile copolymer and an amide dispersion medium, wherein the amide dispersion medium may be at least one selected from the group consisting of dimethylformamide, diethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0044] Here, the weight-average molecular weight was measured using gel permeation chromatography (Waters PL-GPC220) and a Polymer Lavoratories PLgelMIX-B 300mm column under the following conditions.

[0045] Measurement temperature: 40℃

[0046] Flow rate: 0.3 ml / min

[0047] Injection volume: 20 μL

[0048] Standard sample: Polystyrene

[0049] Here, 10 mg of the hydrogenated nitrile copolymer before and after hydrogenation was dissolved in CDCl3 to prepare a sample with a concentration of 25 mg / mL. The sample was then analyzed using 500 MHz NMR (Varian). 1 The degree of hydrogenation was determined by H NMR analysis of the sample and calculated based on the ratio of the peak integral values ​​of the 1,2-bond content (4.8 ppm to 5.1 ppm) to the 1,4-bond content (5.2 ppm to 5.5 ppm) of butadiene before and after hydrogenation.

[0050] Hydrogenated nitrile copolymers

[0051] The present invention provides a hydrogenated nitrile latex comprising a hydrogenated nitrile copolymer with low residual metal content, low molecular weight and low viscosity.

[0052] The hydrogenated nitrile latex of the present invention comprises a hydrogenated nitrile copolymer satisfying the following formulas (1) and (2), having a solvent displacement viscosity of 10 cp to 150 cp and a weight-average molecular weight of 10,000 g / mol or more and less than 80,000 g / mol. The solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C) for a solution in which the hydrogenated nitrile copolymer is dissolved at 16% by weight in an amide dispersion medium.

[0053] Equation (1): Ru + Pd + Rh < 60ppm

[0054] Equation (2): Ca + Mg + Al < 200 ppm

[0055] In equations (1) and (2) above, Ru, Pd, Rh, Ca, Mg, and Al were the contents of each metal ion in the hydrogenated nitrile copolymer determined by ICP-OES (RF power 1300W, plasma gas flow rate 15L / min).

[0056] In addition, Ru+Pd+Rh in formula (1) of the present invention can be less than 60ppm, less than 55ppm, less than 50ppm, less than 45ppm, less than 40ppm, less than 35ppm, less than 30ppm, less than 25ppm or less than 20ppm.

[0057] Furthermore, according to formula (2) of the present invention, Ca+Mg+Al can be less than 200ppm, less than 180ppm, less than 150ppm, less than 110ppm, less than 100ppm, less than 90ppm, less than 80ppm, less than 70ppm, less than 60ppm, less than 50ppm, less than 40ppm, less than 30ppm, less than 20ppm, less than 10ppm or less than 5ppm.

[0058] In addition, according to the present invention, the solvent displacement viscosity of the hydrogenated nitrile copolymer is 10 cp to 150 cp, and the solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C) for a solution in which the hydrogenated nitrile copolymer is dissolved in an amide dispersion medium at 16% by weight.

[0059] In addition, the solvent displacement viscosity of the hydrogenated nitrile copolymer of the present invention can be less than 150 cp, less than 140 cp, less than 130 cp, less than 120 cp, less than 110 cp, or less than 100 cp, and the solvent displacement viscosity can be more than 10 cp, more than 15 cp, more than 20 cp, or more than 30 cp.

[0060] In addition, the solvent displacement viscosity of the hydrogenated nitrile copolymer of the present invention can be 10 cp to 100 cp, 20 cp to 150 cp, or 30 cp to 100 cp.

[0061] The hydrogenated nitrile copolymer of the present invention has the solvent displacement viscosity described above. Therefore, when the hydrogenated nitrile copolymer is contained in the carbon material dispersion, it is easy to suppress the aggregation of the carbon material, and the dispersion viscosity is low, which helps to improve the dispersibility of the carbon material dispersion.

[0062] In addition, the weight-average molecular weight of the hydrogenated nitrile copolymers of the present invention can be 10,000 g / mol or more and less than 80,000 g / mol, 15,000 g / mol to 75,000 g / mol, 15,000 g / mol to 70,000 g / mol, 15,000 g / mol to 65,000 g / mol, 15,000 g / mol to 60,000 g / mol, or 15,000 g / mol to 55,000 g / mol.

[0063] In addition, the degree of hydrogenation of the hydrogenated nitrile copolymer of the present invention can also be 60% or more.

[0064] Typically, hydrogenated nitrile copolymers are prepared through the hydrogenation reaction of nitrile copolymers. Currently, commercially available hydrogenated nitrile copolymers are prepared by dissolving nitrile rubber in a solvent, reacting it with gaseous hydrogen under high temperature and pressure in the presence of a noble metal catalyst to remove the double bonds in the copolymer, and then removing the used catalyst and solvent. This method results in high costs due to the use of high-pressure reactors and noble metal catalysts. To reduce costs, using a small amount of noble metal catalyst leads to a decrease in the hydrogenation rate and an increase in the molecular weight of the resulting hydrogenated nitrile copolymer, which reduces dispersibility and increases viscosity. Furthermore, using appropriate or large amounts of noble metal catalyst results in a large amount of residual metal in the hydrogenated nitrile copolymer, which increases viscosity due to the residual metal and requires costly removal. Furthermore, the preparation of currently commercially available hydrogenated nitrile copolymers involves adding a coagulant (flocculator, AlSO4, MgSO4, CaCl2) to a polymer latex obtained by copolymerizing olefinically unsaturated nitrile monomers with conjugated diene monomers (emulsion polymerization). This causes the latex to coagulate into a nitrile copolymer, which is then dissolved in a solvent to prepare a nitrile copolymer solution for hydrogenation. Therefore, metallic components (Ca, Mg, Al) derived from the coagulant may remain in the hydrogenated nitrile copolymer, leading to increased viscosity.

[0065] However, the hydrogenated nitrile copolymers according to the present invention are obtained by directly hydrogenating a polymer latex obtained by copolymerizing an olefinically unsaturated nitrile monomer and a conjugated diene monomer (emulsion polymerization), thus leaving no metal components derived from the coagulant, resulting in extremely low residual metal content in the rubber, as defined by formulas (1) and (2). Furthermore, the hydrogenated nitrile copolymers possess the aforementioned solvent-displacement viscosity and weight-average molecular weight, exhibiting excellent dispersibility and providing the benefit of eliminating high costs.

[0066] Furthermore, the hydrogenated nitrile copolymers are prepared via C=C double bonds within the conjugated diene monomer units of the hydrogenated nitrile rubber, which is prepared by copolymerizing olefinically unsaturated nitrile monomer units and conjugated diene monomer units, thus comprising olefinically unsaturated nitrile monomer units and conjugated diene monomer units. Therefore, the hydrogenated nitrile copolymers of the present invention may comprise olefinically unsaturated nitrile monomer units and hydrogenated conjugated diene monomer units, and may also comprise conjugated diene monomer units.

[0067] In addition, the weight ratio of olefinic unsaturated nitrile monomer units to hydrogenated conjugated diene monomer units can be from 1:99 to 50:50.

[0068] The olefinically unsaturated nitrile monomer forming the olefinically unsaturated nitrile monomer unit can be at least one selected from acrylonitrile, methacrylonitrile, fumaronitrile, α-chloronitrile, and α-cyanoethyl acrylonitrile. As a specific example, the olefinically unsaturated nitrile monomer can be acrylonitrile or methacrylonitrile, and more specifically, it can be acrylonitrile.

[0069] The conjugated diene monomer forming the hydrogenated conjugated diene monomer unit and the conjugated diene monomer unit can be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and isoprene. As a specific example, the conjugated diene monomer can be 1,3-butadiene.

[0070] In addition, according to the present invention, the hydrogenated nitrile copolymer may further include, as needed, at least one of olefin unsaturated acid monomer units or olefin unsaturated monomer units.

[0071] The olefinic unsaturated acid monomer forming the olefinic unsaturated acid monomer unit can be an olefinic unsaturated monomer containing acidic groups such as carboxyl groups, sulfonic acid groups, and anhydride groups. As a specific example, the olefinic unsaturated acid monomer can include at least one selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid; maleic anhydride, citraconic anhydride, and other polycarboxylic acid anhydrides; styrene sulfonic acid and other olefinic unsaturated sulfonic acid monomers; and olefinic unsaturated polycarboxylic acid ester monomers such as monobutyl fumarate, monobutyl maleate, and mono-2-hydroxypropyl maleate. As a more specific example, the olefinic unsaturated acid monomer can be at least one selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid; and as a more specific example, it can be methacrylic acid. The olefinic unsaturated acid monomer can also be used in the form of a salt, such as an alkali metal salt or an ammonium salt, during polymerization. The content of the olefinic unsaturated acid monomer unit can be from 1% by weight to 5% by weight relative to the total content of the hydrogenated nitrile copolymer.

[0072] Additionally, the olefinically unsaturated monomers forming the olefinically unsaturated monomer units may include (meth)acrylate hydroxyalkyl ester monomers selected from those having 1 to 4 carbon atoms; vinyl aromatic monomers selected from styrene, arylstyrene, and vinylnaphthalene; fluoroalkyl vinyl ether monomers such as fluoroethyl vinyl ether; olefinically unsaturated amide monomers selected from (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N,N-dihydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-propoxymethyl (meth)acrylamide; non-conjugated diene monomers such as vinylpyridine, vinylnorbornene, dicyclopentadiene, and 1,4-hexadiene; and monomers selected from methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylate. The monomers are olefinic unsaturated carboxylic acid esters of butyl acrylate, 2-ethylhexyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, dibutyl maleate, dibutyl fumarate, diethyl maleate, methoxymethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxyethoxyethyl (meth)acrylate, cyanomethyl (meth)acrylate, 2-cyanoethyl (meth)acrylate, 1-cyanopropyl (meth)acrylate, 2-ethyl-6-cyanohexyl (meth)acrylate, 3-cyanopropyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate. The content of the olefinic unsaturated monomer unit may be from 0.5% by weight to 5% by weight relative to the total content of the hydrogenated nitrile copolymer.

[0073] The hydrogenated nitrile copolymer latex according to the present invention may have a solids content of 10% to 30% by weight.

[0074] The hydrogenated nitrile latex of the present invention can be applied to a wide range of applications, such as synchronous belts, seals, hoses, diaphragms, rollers, dispersants, and electrode active material slurry compositions.

[0075] Method for manufacturing hydrogenated nitrile latex

[0076] This invention provides a method for manufacturing hydrogenated nitrile latex with low viscosity, low molecular weight and extremely low metal residue content without the presence of precious metal catalysts.

[0077] A method for manufacturing hydrogenated nitrile latex may include: polymerizing a monomer mixture comprising a conjugated diene monomer and an olefinically unsaturated nitrile monomer in the presence of an emulsifier to prepare a nitrile copolymer (S1); hydrogenating the nitrile copolymer to prepare a hydrogenated nitrile copolymer (S2); subjecting the hydrogenated nitrile copolymer to an ozone decomposition reaction (S3), wherein step (S3) may be carried out by bubbling a mixture of air and ozone into the hydrogenated nitrile copolymer, and the mixture of air and ozone may contain more than 0.1 moles and less than 0.5 moles of ozone.

[0078] In this case, the monomers used to prepare nitrile copolymers are as described above.

[0079] The method for manufacturing hydrogenated nitrile latex according to the present invention will be described in more detail below, and will be broken down into steps.

[0080] Step (S1)

[0081] Step (S1) is the step of preparing a nitrile copolymer by copolymerizing a conjugated diene monomer with an olefinically unsaturated nitrile monomer, which can be carried out by polymerizing a monomer mixture containing a conjugated diene monomer and an olefinically unsaturated nitrile monomer in the presence of an emulsifier.

[0082] In this case, polymerization can be carried out by typical emulsion polymerization, and the emulsifier can be at least one fatty acid salt selected from oleic acid, rosin acid, lauric acid, myristic acid, palmitic acid, stearic acid, naphthalene sulfonic acid and eicosanoic acid; or at least one sulfonate emulsifier selected from sulfosuccinate emulsifiers, disulfonate emulsifiers and linear alkylbenzene sulfonate emulsifiers and mixtures thereof.

[0083] In addition, polymerization can be further carried out using additives such as polymerization initiators and molecular weight regulators. As polymerization initiators, at least one of the following can be used: inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium superphosphate, and hydrogen peroxide; organic peroxides such as tert-butyl peroxide, cumene hydroperoxide, p-menthane hydroperoxide, di-tert-butyl peroxide, tert-butyl isopropylphenyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, benzoyl peroxide, 3,5,5-trimethylhexanol peroxide, and tert-butyl peroxyisobutyrate; and azodimethyl compounds such as azobisisobutyronitrile, azobis-2,4-dimethylpentanonitrile, azobiscyclohexaneformitrile, and methyl azobisisobutyrate.

[0084] In addition, as a molecular weight regulator, at least one selected from the group consisting of n-octylthiol, n-dodecylthiol, n-decylthiol, tert-dodecylthiol, 2,2,4,6,6-pentamethylheptane-4-thiol and 2,2,4,6,6,8,8-heptamethylnonane-4-thiol can be used.

[0085] In addition, during polymerization, additives such as activators, chelating agents, dispersants, pH adjusters, deoxidizers, particle size adjusters, anti-aging agents, and oxygen scavengers can be used as needed without reducing the physical properties of the rubber.

[0086] Furthermore, polymerization can be carried out at temperatures ranging from 10°C to 90°C or from 10°C to 75°C.

[0087] Alternatively, a polymerization terminator can be added after polymerization initiation to terminate the polymerization. In this case, the polymerization terminator can be a commonly used polymerization terminator in the art, such as hydroxylamine, N,N-diethylhydroxylamine, hydroxylamine sulfate, diethylhydroxylamine, hydroxylamine sulfonic acid and its alkali metal ion salts, sodium dimethyl dithiocarbamate, hydroquinone derivatives, such as aromatic hydroxy dithiocarboxylic acids like hydroxydiethylphenyl dithiocarboxylic acid and hydroxydibutylphenyl dithiocarboxylic acid.

[0088] Alternatively, nitrile copolymers can be obtained in the form of latex after polymerization, or typical post-processing steps can be performed, such as at least one post-processing step selected from coagulation, solvent removal or precipitation, and drying, to obtain nitrile copolymers.

[0089] In this context, latex refers to a dispersion (emulsion) in which polymer particles are dispersed in a liquid phase.

[0090] Step (S2)

[0091] Step (S2) is to hydrogenate the prepared nitrile copolymer to produce a hydrogenated nitrile copolymer. The hydrogenation can be carried out in the presence of an oxidizing agent and a reducing agent.

[0092] The oxidant may be at least one selected from oxygen and peroxide, and the peroxide may be hydrogen peroxide. The oxidant may be present in an amount of 1 to 100 parts by weight, 5 to 80 parts by weight, 10 to 70 parts by weight, 15 to 50 parts by weight or 20 to 40 parts by weight relative to 100 parts by weight of the nitrile copolymer.

[0093] In addition, the reducing agent may be at least one selected from hydrazine and hydrazine hydrate, and may be present in an amount of 1 to 100 parts by weight, 1 to 50 parts by weight, 2 to 40 parts by weight, 3 to 30 parts by weight or 5 to 20 parts by weight relative to 100 parts by weight of the nitrile copolymer.

[0094] In addition, the hydrogenation reaction can be carried out at temperatures ranging from 30°C to 90°C, or from 40°C to 70°C, for 6 to 20 hours or 8 to 16 hours.

[0095] Step (S3)

[0096] Step (S3) is the step of manufacturing hydrogenated nitrile latex from the prepared hydrogenated nitrile copolymer, which can be carried out by subjecting the hydrogenated nitrile copolymer to an ozone decomposition reaction.

[0097] The ozone decomposition reaction can be carried out by bubbling a mixture of air and ozone into a hydrogenated nitrile copolymer to remove any remaining reducing agent and break down the polymer chains to a lower molecular weight. In this case, the mixture of air and ozone may contain more than 0.1 moles and less than 0.5 moles or 0.1 moles to 0.3 moles of ozone.

[0098] In addition, ozone decomposition reactions can be carried out at temperatures ranging from 0°C to 75°C.

[0099] carbon material dispersion

[0100] This invention provides a carbon material dispersion with excellent dispersibility.

[0101] The carbon material dispersion of the present invention may comprise carbon material, dispersion medium and hydrogenated nitrile copolymer, wherein the hydrogenated nitrile copolymer may satisfy the following formulas (1) and (2), having a solvent displacement viscosity of 10 cp to 150 cp and a weight-average molecular weight of 10,000 g / mol or more and less than 80,000 g / mol. For a solution in which the hydrogenated nitrile copolymer is dissolved in an amide dispersion medium at 16% by weight, the solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C).

[0102] Equation (1): Ru + Pd + Rh < 60 ppm

[0103] Equation (2): Ca + Mg + Al < 200 ppm

[0104] In equations (1) and (2) above, Ru, Pd, Rh, Ca, Mg, and Al were the contents of each metal ion in the hydrogenated nitrile copolymer determined by ICP-OES (RF power 1300W, plasma gas flow rate 15L / min).

[0105] The specific details of the hydrogenated nitrile copolymers in the carbon material dispersion are as described above.

[0106] In addition, the viscosity of the carbon material dispersion of the present invention can be above 1000 cp and less than 15000 cp, 2000 cp to 10000 cp, or 2000 cp to 5000 cp. In this case, the carbon materials will not agglomerate with each other and have excellent dispersibility.

[0107] Furthermore, the carbon material of the present invention may be at least one selected from carbon black, Ketjen black, fullerene, graphene, carbon nanotubes, carbon black, and graphite. The aforementioned carbon material may be included in the carbon material dispersion in an amount of 1% to 10% by weight, 2% to 8% by weight, or 3% to 7% by weight. In this case, the carbon material dispersion containing the carbon material exhibits excellent dispersibility, and therefore can demonstrate excellent processability and conductivity, resulting in excellent battery performance.

[0108] Furthermore, the hydrogenated nitrile copolymer can be included in the carbon material dispersion in amounts ranging from 0.2 wt% to 4.0 wt%, 0.4 wt% to 3.2 wt%, or 0.6 wt% to 2.8 wt%. In this case, the carbon material dispersion containing the hydrogenated nitrile copolymer exhibits excellent dispersibility, thus demonstrating excellent processability and conductivity, resulting in superior battery performance.

[0109] Alternatively, the dispersion medium can be a solvent commonly used in the art, such as N-methyl-2-pyrrolidone, dimethyl sulfoxide, isopropanol, acetone, or water, which can be used alone or in combination. In this case, the amount of dispersion medium used can be appropriately adjusted taking into account the viscosity of the carbon material dispersion.

[0110] Meanwhile, the carbon material dispersion according to the present invention can be prepared by mixing carbon material, hydrogenated nitrile copolymer and dispersion medium, and in this case, the mixing can be carried out at a temperature condition that does not change the physical properties. For example, the mixing can be carried out at a temperature below 50°C or between 5°C and 50°C.

[0111] As long as the carbon material and the hydrogenated nitrile copolymer are evenly dispersed in the carbon material dispersion, there are no particular restrictions. They can be mixed by typical mixing methods, such as ball mills, bead mills, disc mills, basket mills, high-pressure homogenizers, etc.

[0112] Meanwhile, the carbon material dispersion according to the present invention can be used in electrode active material slurry compositions.

[0113] Example

[0114] The present invention will now be described in more detail through embodiments. However, the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0115] Example 1

[0116] 450g of acrylonitrile copolymer (NBR6240, 34 wt%, MV41, LG CHEM) was placed in a 3L reactor, along with 48g of hydrazine and 130g of hydrogen peroxide. The mixture was then subjected to a hydrogenation reaction at 40°C for 16 hours. Subsequently, an air / ozone mixture containing 0.2 mol of ozone was bubbled into the hydrogenated acrylonitrile rubber latex through a glass tube to induce an ozone decomposition reaction, thereby producing a hydrogenated acrylonitrile latex containing the acrylonitrile copolymer (solids content: 21 wt%).

[0117] Example 2

[0118] Compared to Example 1, except that an air / ozone mixture containing 0.1 mol of ozone was used for the ozone decomposition reaction, hydrogenated nitrile latex (solid content: 21 wt%) was manufactured in the same manner as in Example 1.

[0119] Example 3

[0120] Compared to Example 1, except that an air / ozone mixture containing 0.3 mol of ozone was used for the ozone decomposition reaction, the hydrogenated nitrile latex (solid content: 21 wt%) was manufactured in the same manner as in Example 1.

[0121] Example 4

[0122] Compared to Example 1, except that the hydrogenation reaction was carried out at 43°C and the ozone decomposition reaction was carried out using an air / ozone mixture containing 0.1 mol of ozone, the hydrogenated nitrile latex (solid content: 21 wt%) was manufactured in the same manner as in Example 1.

[0123] Comparative Example 1

[0124] A polymer comprising 34 wt% acrylonitrile and 66 wt% 1,3-butadiene in 270 g of chlorobenzene was introduced into a high-pressure reactor. The reactor was degassed three times with pure H2 (100 psi to 200 psi) under vigorous stirring. The reactor temperature was raised to 130 °C. A solution of 3.9 g (0.076 phr) of tris(triphenylphosphine)-rhodium(I) chloride catalyst and 0.232 g of triphenylphosphine (TPP) as a co-catalyst in 60 mL of monochlorobenzene with an oxygen content of less than 5 ppm was introduced into the reactor under hydrogenation to produce a hydrogenated nitrile latex (solids content: 21 wt%) containing a hydrogenated nitrile copolymer. Hydrogenation was carried out by raising the reactor temperature to 138 °C and setting the pressure to 1200 psi (83 atm), wherein the temperature and hydrogen pressure within the reactor were kept constant throughout the reaction.

[0125] Comparative Example 2

[0126] A 400 mL (total solids 48 g) latex solution (in which deionized water was added to a polymer containing 34 wt% acrylonitrile and 66 wt% 1,3-butadiene to adjust the total solids concentration to 12 wt%) was placed in a 1 L autoclave equipped with a stirrer. Nitrogen gas was circulated for 10 minutes to remove dissolved oxygen from the solution, and then a hydrogenation catalyst was added. In this case, the hydrogenation catalyst was prepared by dissolving 75 mg palladium acetate in 180 mL of deionized water, with 4 molar equivalents of nitric acid added relative to palladium (Pd). After purging the reactor twice with hydrogen, the reactor was pressurized to 3 MPa and heated to 50 °C for 6 hours to produce a hydrogenated nitrile latex (21 wt% solids content) containing a hydrogenated nitrile copolymer.

[0127] Comparative Example 3

[0128] Compared to Example 1, except that an air / ozone mixture containing 0.05 mol of ozone was used for ozone decomposition reaction, hydrogenated nitrile latex (solid content: 21 wt%) was manufactured in the same manner as in Example 1.

[0129] Comparative Example 4

[0130] Compared to Example 1, except that an air / ozone mixture containing 0.5 mol of ozone was used for the ozone decomposition reaction, hydrogenated nitrile latex (solid content: 21 wt%) was manufactured in the same manner as in Example 1.

[0131] Comparative Example 5

[0132] Compared to Example 1, except that an air / ozone mixture containing 0.08 mol of ozone was used for ozone decomposition reaction, hydrogenated nitrile latex (solid content: 21 wt%) was manufactured in the same manner as in Example 1.

[0133] Comparative Example 6

[0134] Compared to Example 1, except that the hydrogenation reaction was carried out at 37°C and the ozone decomposition reaction was carried out using an air / ozone mixture containing 0.5 mol of ozone, the hydrogenated nitrile latex (solid content 21% by weight) was manufactured in the same manner as in Example 1.

[0135] Experimental Example 1

[0136] The residual metal content and viscosity of the hydrogenated nitrile copolymers in the hydrogenated nitrile latexes manufactured in the Examples and Comparative Examples were determined, and the results are shown in Table 1 below.

[0137] (1) Residual metal content (ppm)

[0138] Hydrogenated nitrile copolymer latexes were dried in a vacuum oven at 60°C for 24 hours to prepare hydrogenated nitrile copolymers. Then, 0.1 g of each hydrogenated nitrile copolymer was diluted in 15 mL of hydrofluoric acid, and the mixture was heat-treated from room temperature (23±5°C) to 250°C for 90 minutes, followed by holding for 60 minutes to prepare samples for ICP-OES analysis. The residual metal content in each hydrogenated nitrile copolymer was determined using an ICP-OES apparatus with an RF power of 1300 W and a plasma gas flow rate of 15 L / min. The detection limit for quantitative analysis using the ICP-OES apparatus was 60 ppm.

[0139] (2) Viscosity

[0140] In a 5-liter sealed flask connected to a mechanical paddle stirrer, a reflux condenser, an inlet pipe for supplying N-methyl-2-pyrrolidone (NMP), and a vacuum pump, 600 g of each hydrogenated nitrile latex (100 g of rubber, 17 wt% solids content) was stirred for 1 hour while 525 L of N-methyl-2-pyrrolidone (NMP) was added dropwise using the pump. After the addition was completed, the sealed flask was heated to 90°C and the pressure was reduced to 10 Torr by running the vacuum pump. The pressure was reduced for 2 hours to completely remove water to prepare a 16 wt% solvent-displaced solution, which was then measured using a Brookfield viscometer (#63 rotor, 25°C).

[0141] (3) Weight-average molecular weight (g / mol)

[0142] Gel permeation chromatography (Waters PL-GPC220) measurements were performed using a Polymer Lavoratories PLGel Mix-B 300mm column under the following conditions.

[0143] Measurement temperature: 40℃

[0144] Flow rate: 0.3 ml / min

[0145] Injection volume: 20 μL

[0146] Standard sample: Polystyrene

[0147] [Table 1]

[0148] As shown in Table 1 above, Examples 1 to 3 were determined to each have a residual metal content of less than 60 and less than 200 as defined by Formulas (1) and (2), and a solvent displacement viscosity of 10 cp to 150 cp, and simultaneously have a weight-average molecular weight of 10,000 g / mol to 80,000 g / mol. On the other hand, Comparative Examples 1 and 2, obtained by coagulating a nitrile copolymer latex manufactured in a latex state by emulsion polymerization using coagulants (AlSO4, MgSO4, CaCl2) to obtain rubber, and then adding solvent to prepare a latex solution for hydrogenation reaction, showed a significant increase in residual metals caused by the noble metal catalyst and residual metals caused by the coagulant, as well as an increase in viscosity caused by such residual metals, compared to the Examples.

[0149] In addition, Comparative Examples 3 to 6 had the same residual metal content as the Examples, but in Comparative Example 3, the ozone reaction did not proceed well, so the viscosity and weight-average molecular weight greatly exceeded the limit range, while in Comparative Example 4, the viscosity was significantly reduced due to excessive splitting of the polymer chain.

[0150] Meanwhile, the ICP-OES device is used to detect very small amounts of metal ions; therefore, some metal components may be detected due to residual components that may be contained in the feedstock, residual components in the device, or contamination. Therefore, small amounts of Ca, Mg, and / or Al are expected to be detected in Examples 1 to 3 and Comparative Examples 3 and 4. Furthermore, with a detection limit of 60 ppm for the ICP-OES device, Ru + Pd + Rh < 60 ppm is interpreted as undetectable.

[0151] Experimental Example 2

[0152] Carbon material predispersants containing the hydrogenated nitrile latexes manufactured in the Examples and Comparative Examples were prepared, and their viscosities were measured. The results are shown in Table 2 below.

[0153] (1) Preparation of carbon material predispersants

[0154] In a 5-liter sealed flask connected to a mechanical paddle stirrer, a reflux condenser, an inlet pipe for supplying N-methyl-2-pyrrolidone (NMP), and a vacuum pump, 600 g of each hydrogenated nitrile latex (100 g of rubber, 17 wt% solids content) was stirred for 1 hour while 525 L of N-methyl-2-pyrrolidone (NMP) was added dropwise using the pump. After the addition was completed, the sealed flask was heated to 90°C and the pressure was reduced to 10 Torr by running the vacuum pump. The pressure was reduced for 2 hours to completely remove water, thus preparing a solvent displacement solution in which the hydrogenated nitrile copolymer was dissolved in N-methyl-2-pyrrolidone at 16 wt%. A carbon material dispersion was prepared by mixing 3.3 g of carbon nanotubes, 96 g of NMP as a dispersion medium, 0.66 g of each solvent displacement solution (for hydrogenated nitrile copolymers), and 700 g of zirconia beads with a diameter of 1 mm, and then grinding them at 8000 rpm for 1 hour using a Dispemat-CC (VMA-Getzmann) and a disc mill.

[0155] (2) Viscosity

[0156] The carbon material predispersion was measured using a viscometer (Viscometer TV-22, TOKI) at 25°C and 1 rpm.

[0157] [Table 2]

[0158] As shown in Table 2 above, compared with Comparative Examples 1 and 3 to 6, the viscosities of Examples 1 to 4 ranged from 3300 cp to 8200 cp, showing a significantly reduced viscosity characteristic. On the other hand, in the case of Comparative Example 2, due to the excessively high molecular weight of the hydrogenated nitrile copolymer, the dispersion was insufficient during the preparation of the carbon material predispersion, making viscosity measurement impossible.

[0159] Furthermore, it is believed that in Comparative Example 4, due to the low viscosity and molecular weight of the hydrogenated nitrile copolymer, the aggregation of carbon material was not suppressed during the preparation of the carbon material predispersant, resulting in insufficient dispersion and a significantly lower dispersion viscosity compared to the examples.

Claims

1. A hydrogenated nitrile latex comprising a hydrogenated nitrile copolymer satisfying formulas (1) and (2) below, wherein the solvent displacement viscosity of the hydrogenated nitrile latex is 10 cp to 150 cp, and the weight-average molecular weight is 10,000 g / mol or more and less than 80,000 g / mol, wherein the solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C) on a solution in which the hydrogenated nitrile copolymer is dissolved at 16% by weight in an amide dispersion medium. Equation (1): Ru + Pd + Rh < 60 ppm Equation (2): Ca + Mg + Al < 200 ppm in, In equations (1) and (2) above, The contents of Ru, Pd, Rh, Ca, Mg and Al in the hydrogenated nitrile copolymer were determined by ICP-OES (RF power 1300 W, plasma gas flow rate 15 L / min).

2. The hydrogenated nitrile latex according to claim 1, wherein, In equation (1) above, Ru+Pd+Rh is less than 50 ppm, and in equation (2) above, Ca+Mg+Al is less than 200 ppm.

3. The hydrogenated nitrile latex according to claim 1, wherein, In equation (1) above, Ru+Pd+Rh is less than 50 ppm, and in equation (2) above, Ca+Mg+Al is less than 100 ppm.

4. The hydrogenated nitrile latex according to claim 1, wherein, The solvent displacement viscosity of the hydrogenated nitrile copolymer is 10 cp to 100 cp.

5. The hydrogenated nitrile latex according to claim 1, wherein, The weight-average molecular weight of the hydrogenated nitrile copolymer is from 15,000 g / mol to 55,000 g / mol.

6. The hydrogenated nitrile latex according to claim 1, wherein, The hydrogenated nitrile copolymer has a hydrogenation degree of over 60%.

7. The hydrogenated nitrile latex according to claim 1, wherein, The hydrogenated nitrile copolymer comprises olefinically unsaturated nitrile monomer units and hydrogenated conjugated diene monomer units.

8. The hydrogenated nitrile latex according to claim 7, wherein, The weight ratio of the olefinic unsaturated nitrile monomer unit to the hydrogenated conjugated diene monomer unit is 1:99 to 50:

50.

9. The hydrogenated nitrile latex according to claim 7, wherein, The hydrogenated nitrile copolymer also contains conjugated diene monomer units.

10. A method for manufacturing a hydrogenated nitrile latex comprising a hydrogenated nitrile copolymer, the method comprising: A monomer mixture containing conjugated diene monomers and olefinically unsaturated nitrile monomers is polymerized in the presence of an emulsifier to prepare a nitrile copolymer (S1). The nitrile copolymer is hydrogenated to prepare a hydrogenated nitrile copolymer (S2); and The hydrogenated nitrile copolymer is subjected to an ozone decomposition reaction (S3). Step (S3) is carried out by bubbling a mixture of air and ozone into the hydrogenated nitrile copolymer, and The mixture of air and ozone contains more than 0.1 mol and less than 0.5 mol of ozone.

11. The method according to claim 10, wherein, The hydrogenation in step (S2) is carried out in the presence of an oxidizing agent and a reducing agent.

12. The method according to claim 10, wherein, The ozone decomposition reaction in step (S3) is carried out at a temperature of 0°C to 75°C.

13. A carbon material dispersion comprising a carbon material, a dispersion medium, and a hydrogenated nitrile copolymer, in, The hydrogenated nitrile copolymer satisfies the following formulas (1) and (2), has a solvent displacement viscosity of 10 cp to 150 cp, and a weight-average molecular weight of 10,000 g / mol or more and less than 80,000 g / mol. The solvent displacement viscosity is determined using a Brookfield viscometer (#63 rotor, 25°C) on a solution of the hydrogenated nitrile copolymer dissolved in an amide dispersion medium at 16% by weight. Equation (1): Ru + Pd + Rh < 60 ppm Equation (2): Ca + Mg + Al < 200 ppm In equations (1) and (2) above, The contents of Ru, Pd, Rh, Ca, Mg and Al in the hydrogenated nitrile copolymer were determined by ICP-OES (RF power 1300 W, plasma gas flow rate 15 L / min).

14. The carbon material dispersion according to claim 13, having a viscosity of 1000 cp or more and less than 15000 cp.

15. The carbon material dispersion according to claim 13, wherein, The carbon material is selected from at least one of the following groups: carbon black, Ketjen black, fullerene, graphene, carbon nanotubes, carbon black, and graphite.

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