Methods for making polymer masterbatches and formulations containing both carbon black and carbon nanotubes - Patent Application 20070122999

Abstract

The present invention relates to methods for making polymer masterbatches by melt processing a first base polymer and carbon nanotubes to form a first polymer mixture, and then melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch. Related methods for making polymer compositions can further include melt processing the polymer masterbatch and a bulk polymer to form a polymer composition. These methods can be used to improve surface resistivity properties over traditional compounding and masterbatch preparation techniques.

Description

[Technical Field]

[0001] (Reference to Related Application) This application is a PCT International patent application filed on March 12, 2024, and claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 489,797, filed on March 13, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to polymer masterbatches and subsequent formulations containing both a base polymer and carbon black and carbon nanotube additives, and more particularly to methods for making such polymer masterbatches and formulations having improved surface resistivity properties. [Background technology]

[0003] Carbon nanotubes can be used in combination with carbon black fillers in polymer formulations to improve electrical conductivity with a relatively small weight gain. However, it is often difficult to uniformly disperse both carbon nanotubes and carbon black in a polymer matrix, and therefore it would be beneficial to develop new methods to improve filler dispersibility. Accordingly, the present invention is generally directed to these ends. Summary of the Invention [Problem to be solved by the invention]

[0004] In accordance with one or more objects of the present invention, as embodied and broadly described herein, the present invention relates to methods for making polymer masterbatches and polymer compositions containing at least one polymer, carbon black, and carbon nanotubes. [Means for solving the problem]

[0005] In one aspect, there is provided a method for producing a polymer masterbatch, in this aspect the method may comprise: (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture; and (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch;

[0006] In another aspect, there is provided a method for producing a polymer composition, in this aspect, the method may include: (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture; (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch; and (iii) melt processing the polymer masterbatch with a bulk polymer to form a polymer composition;

[0007] Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments and, together with the description, serve to explain certain principles of the invention. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 illustrates four methods that can be used to prepare polymer masterbatches and polymer compositions. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention may be understood more readily by reference to the following detailed description of the invention and the examples included therein.

[0011] Before the present compounds, compositions, articles, systems, devices, and / or methods are disclosed and described, it is to be understood that they are not limited to particular synthetic methods or to particular reagents, unless otherwise specified, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments, and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and materials are now described.

[0012] All publications (including ASTM methods) mentioned herein are incorporated by reference in their entirety to disclose and describe the methods and / or materials in connection with which the publications are cited.

[0013] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, exemplary methods and materials are described herein.

[0014] As used herein, unless specifically stated to the contrary, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "polymer" or "carbon black" includes a mixture of two or more polymers or carbon blacks, respectively.

[0015] Ranges can be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it is understood that the particular value forms another aspect. It is further understood that the beginning and end points of each range are significant both in relation to the other point (endpoint or beginning point), and independently of the other point. It is also understood that there are a number of values ​​disclosed herein, and that each value is also herein disclosed as "about" that particular value in addition to the value itself. For example, if the numerical value "10" is disclosed, then both "10" and "about 10" are disclosed. It is also understood that each unit between two particular units is disclosed. For example, if "10" and "15" are disclosed, then "11," "12," "13," and "14" are also disclosed.

[0016] As used herein, the term "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and the description includes instances where the event or circumstance occurs and instances where it does not occur.

[0017] The term "polymer masterbatch" refers to a mixture of one or more base polymers with a high concentration of carbon fillers (carbon black and carbon nanotubes) and any other additives, such as dispersing additives, pigments, dyes, colorants, etc.

[0018] The term "base polymer" refers to the polymer with which the carbon nanotubes and carbon black (and any additives) are mixed during the melt processing step to form the polymer masterbatch. When both a first base polymer and a second base polymer are used, the base polymers can be the same or different.

[0019] The term "melt processing" encompasses melt mixing and melt blending and can be accomplished using any suitable melt processing technique and equipment.

[0020] Melt processing of polymer masterbatches and "bulk polymers" is a processing step in which the masterbatch and bulk polymer (along with any other additives) are mixed to form the final polymer composition or blend. The term "bulk polymer" refers to the polymer resin that is mixed with the masterbatch to form the final polymer blend. The bulk polymer can be the same or different from one or more base polymers.

[0021] Disclosed are the components used to prepare the compositions of the invention, as well as the compositions themselves used within the methods disclosed herein. These and other materials are disclosed herein, and when combinations, subsets, interactions, groups, etc. of these materials are disclosed, it should be understood that specific reference to various individual and collective combinations and permutations of each of these compounds is specifically contemplated and described herein, even if they may not be explicitly disclosed. For example, when a particular compound is disclosed and discussed, and numerous modifications that can be made to numerous molecules comprising this compound are discussed, any and all combinations and permutations of this compound and its possible modifications are specifically contemplated unless specifically indicated to the contrary. Thus, if species of molecules A, B, and C are disclosed, as are species of molecules D, E, and F, and an example of a molecule AD is disclosed, AE, AF, BD, BE, BF, CD, CE, and CF are considered disclosed, each representing the combination of meanings individually and collectively intended, even if not individually listed. Similarly, any subset or combination of these is also disclosed. Thus, for example, the subgroups AE, BF, and CE are considered disclosed. This concept applies to all aspects of this application, including, but not limited to, steps in methods of making and using the compositions of the invention. Thus, where there are various additional steps that may be performed, it is understood that each of these additional steps can be performed with any particular embodiment or combination of embodiments of the methods of the invention.

[0022] Each of the materials disclosed herein is either commercially available and / or methods for its production are known to those skilled in the art.

[0023] It is understood that the compositions prepared by the disclosed methods have a specific function. Disclosed herein are certain structural requirements for performing the disclosed function, and it is understood that there are various structures that can perform the same function related to the disclosed structures, and that these structures will typically achieve the same result.

[0024] Unless indicated otherwise, parts are parts by weight, temperature is in ° C. or is at ambient temperature, and pressure is at or near atmospheric.

[0025] A. Method As briefly discussed above, methods of making a polymer masterbatch disclosed herein can include (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture, and (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch. Another method disclosed herein is directed to a method of making a polymer composition, the method including (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture, (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch, and (iii) melt processing the polymer masterbatch with a bulk polymer to form a polymer composition.

[0026] In both of these methods, any suitable technique and equipment can be used for each melt-processing step. Nevertheless, the melt-processing in steps (i), (ii), and (iii) can often be carried out independently in a single-screw extrusion system, a twin-screw extrusion system, or a Banbury mixer. When a twin-screw extrusion system (e.g., a counter-rotating mixer or a co-rotating twin-screw extrusion system) is utilized, any combination of feeding, melting, mixing, and conveying elements can be employed.

[0027] With respect to step (i), the first base polymer and the carbon nanotubes may be in any suitable form. For example, the first base polymer may be in the form of fluff, powder, granules, pellets, etc., and the carbon nanotubes may be in the form of a powder or granules. Often, the carbon nanotubes are present in powder form in step (i).

[0028] After melt processing, the first polymer mixture obtained in step (i) can contain any suitable amount of carbon nanotubes. In one embodiment, the first polymer mixture can comprise 0.5 to 10 wt. % of the carbon nanotubes, while in another embodiment, the first polymer mixture can comprise 1 to 6 wt. % of the carbon nanotubes.

[0029] In step (ii), the first polymer mixture from step (i) is combined with carbon black and melt-processed to form a polymer masterbatch. Optionally, a second base polymer can be combined with the first polymer mixture and carbon black, and the second base polymer can be the same as or different from the first base polymer. The first polymer mixture and carbon black (and the second base polymer, if used) can be in any suitable form. Often, the carbon black is present in powder or bead form in step (ii). Typical properties of the polymer masterbatch are described below.

[0030] When preparing a final polymer composition from the polymer masterbatch by step (iii), the polymer masterbatch and bulk polymer are combined and melt processed to form a polymer composition, the typical properties of which are described below.

[0031] Reference is now made to Figure 1, which is a schematic diagram illustrating four methods that can be used to prepare polymer masterbatches and polymer compositions. Method 1 is illustrative of the inventive method for producing the polymer masterbatches and polymer compositions disclosed herein. In Method 1, labeled Double Pass in Figure 1, carbon nanotubes (CNTs) and a polymer are melt-processed (e.g., via extrusion) to form a first polymer mixture (CNT MB), which is then combined (e.g., via extrusion) with carbon black (CB) and optionally another polymer to form a polymer masterbatch (CB / CNT MB). To form the final polymer composition, additional polymer is added (e.g., via extrusion) to form a representative polymer composition containing a 1:9:90 weight ratio of CNTs:CBs:polymer.

[0032] In Method 2, labeled Single-Pass Powder Mixing in FIG. 1, CB and CNTs are combined with a polymer in one step (e.g., via extrusion) to form a polymer masterbatch (CB / CNT MB), which is then combined with another polymer (e.g., via extrusion) to form a representative polymer composition containing a CNT:CB:polymer weight ratio of 1:9:90.

[0033] In methods 3 and 4, labeled Masterbatch in FIG. 1, a commercially available or homemade masterbatch containing CNTs is combined (e.g., via extrusion) with CB (e.g., in powder form) and a polymer (e.g., polypropylene, PP) to form a representative polymer composition containing CNT:CB:polymer in a weight ratio of 1:9:90.

[0034] Unexpectedly, it has been found that Method 1 of FIG. 1 produces polymer masterbatches and subsequent polymer compositions or formulations containing both carbon black and carbon nanotube additives that have improved surface resistivity properties, even when the amounts of each of carbon black, carbon nanotubes, and polymer are the same.

[0035] B. Polymer Masterbatch In one embodiment, the polymer masterbatch prepared herein comprises a base polymer (or base polymers) and 20-70 wt. % carbon black and carbon nanotubes. More often, 25-50 wt. % (e.g., 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, or 50 wt. %) of the polymer masterbatch is carbon black and carbon nanotubes. The weight ratio of carbon black to carbon nanotubes in the polymer masterbatch can range from 70:30 to 99.5:0.5, and in some embodiments, the weight ratio of carbon black to carbon nanotubes in the polymer masterbatch is within the range of 85:15 to 98:2. In yet another embodiment, the weight ratio of carbon black to carbon nanotubes in the polymer masterbatch can be about 95:5.

[0036] The polymer masterbatch composition can optionally include a dispersing additive or other suitable additive. In one embodiment, the masterbatch composition can include a dispersing additive in an amount ranging from 0.01% to 20% by weight. Other optional additives that can be present in the polymer masterbatch include, but are not limited to, pigments, dyes, or other materials to impart color to articles or coatings prepared from the polymer masterbatch composition.

[0037] C. Polymer Composition In one embodiment, the polymer compositions prepared herein, including a bulk polymer (or bulk polymers) and a polymer masterbatch, can contain 20-70 wt. % carbon black and carbon nanotubes. Without limitation, 1-30 wt. % of the final polymer composition is carbon black and carbon nanotubes. More often, 5-15 wt. % (e.g., 5 wt. %, 8 wt. %, 10 wt. %, 12 wt. %, or 15 wt. %) of the polymer composition is carbon black and carbon nanotubes. The weight ratio of carbon black to carbon nanotubes in the polymer composition can range from 70:30 to 99.5:0.5, and in some embodiments, the weight ratio of carbon black to carbon nanotubes in the polymer composition is within the range of 85:15 to 98:2. In yet another embodiment, the weight ratio of carbon black to carbon nanotubes in the polymer composition can be approximately 95:5.

[0038] As will be appreciated by those skilled in the art, the final polymer composition containing a particular loading of polymer masterbatch can contain a variety of additive and polymer combinations depending on the end use of the polymer composition.

[0039] D. Base Polymers and Bulk Polymers The methods for producing polymer masterbatches and polymer compositions can utilize a variety of base polymers and bulk polymers. Generally, any polymer can be utilized as a carrier for the masterbatch composition or for forming the final polymer composition. Thus, the first base polymer, the second base polymer, and the bulk polymer can independently comprise a thermoplastic polymer, a thermosetting polymer, an elastomeric polymer, or a combination thereof. Specific, non-limiting examples include polyolefins such as polyethylene or polypropylene (e.g., Braskem PP D115A), polyamides, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene, polycarbonate, polyesters, and the like, as well as combinations thereof.

[0040] E. Carbon black The carbon black filler can comprise any suitable carbon black material. In one aspect, the carbon black can comprise conductive or semiconductive carbon black. In another aspect, the carbon black can comprise high-structure carbon black. High-structure carbon black can increase compound viscosity, modulus, and conductivity. High structure can also reduce die swell, loading capacity, and improve dispersibility. Lower-structure carbon black can reduce compound viscosity and modulus, increase elongation, die swell, and loading capacity, but can also reduce dispersibility. If all other characteristics of the carbon black are held constant, a narrow aggregate size distribution increases the difficulty of carbon black dispersion, increases hysteresis, and decreases resilience.

[0041] In one embodiment, the carbon black has a viscosity of 25 to 250 mPa s, as measured according to ASTM D6556(2015). 2 In a further embodiment, the carbon black has a nitrogen surface area (NSA) of 40 to 90 m / g, as measured according to ASTM D6556(2015). 2 / g nitrogen surface area (NSA).

[0042] Additionally or alternatively, the carbon black may have a viscosity of 45 to 250 cm as measured in accordance with ASTM D2414(2019). 3 For example, the carbon black has an oil absorption number (OAN) of 45, 50, 60, 70, 80, 90, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 200, 220, or 250 cc / 100g, as measured in accordance with ASTM D2414(2019). In a further embodiment, the carbon black has an oil absorption number of 120 to 210 cm3, as measured in accordance with ASTM D2414(2019). 3 / 100g, or 120~170cm3 It has an oil absorption number (OAN) of 100g.

[0043] In various specific embodiments, the carbon black can include Birla Carbon 7055, 7060, 7067, CONDUCTEX 7055 ULTRA, CONDUCTEX KU, CONDUCTEX SCU, RAVEN P, RAVEN P7U, or RAVEN PFEB carbon black available from Birla Carbon of Marietta, Georgia, USA. Other suitable carbon blacks can be used.

[0044] The basic methods for producing carbon black are well known. Generally, carbon black is produced by partial oxidation or pyrolysis of hydrocarbon gases or liquids, where a hydrocarbon feedstock (hereinafter referred to as "feed hydrocarbon") is injected into a hot gas stream, where it is pyrolyzed and converted into smoke before being quenched with water spray. The hot gases are produced by burning fuel in a combustion section. From the combustion section, the hot gases flow into a reaction section in open communication with the combustion section. The feed hydrocarbons are introduced into the hot gases as they flow through the reaction section, thereby forming a reaction mixture containing particles that form carbon black. The reaction mixture flows from the reactor to a cooling section in open communication with the reaction section. At a location within the cooling section, one or more quench sprays, e.g., water, are introduced into the flowing reaction mixture, thereby reducing the temperature of the reaction mixture below that required for carbon black production and quenching the carbon-forming reaction. The black particles are then separated from the hot gas stream. Through controlled manipulation of the reactor conditions, a wide range of carbon black types can be produced.

[0045] F. Carbon nanotubes Any suitable carbon nanotubes can be used to prepare the masterbatch composition. In one aspect, the carbon nanotubes include multi-walled carbon nanotubes, single-walled carbon nanotubes, or a mixture thereof. The multi-walled carbon nanotubes, if present, can vary in diameter, aspect ratio, or purity.

[0046] In some embodiments, the carbon nanotubes have an average diameter of 1.5 to 25 nm. In further embodiments, the carbon nanotubes have an average diameter of 9 to 15 nm. In one embodiment, the carbon nanotubes have an average length of 1 to 50 μm. In a further embodiment, the carbon nanotubes have an average length of 1.5 to 15 μm. A specific, non-limiting example of a carbon nanotube grade useful in the methods disclosed herein is NC7000, available from Nanocyl. [Example]

[0047] Various exemplary embodiments of the present invention are detailed below, which are intended to be illustrative and not to limit the scope of the present invention.

[0048] The surface resistivity of the polymer compositions prepared by the polymer masterbatches was measured using Loresta-GP (MCP-T600) or Hiresta-UP (MCP-HT450) at 90 V and 100 V, respectively.

[0049] Examples 1-9 are summarized in Table 1 below. Referring to Figure 1, Example 1 was prepared according to Method 2. High-melt-flow PP (PP1105E1, 34 g / 10 min MFR) was extruded at 255 °C with beaded CONDUCTEX 7055 ULTRA carbon black and powdered Nanocyl NC7000 (the CB:CNT weight ratio was 95:5) to produce a 25 wt% carbon black additive masterbatch (25 wt% total CB and CNT). This 25 wt% masterbatch was then melt-processed with virgin polypropylene (Braskem PP D115A) resin at 230 °C using a twin-screw extruder (16 mm, 25:1) to yield a final polymer composition containing CNT:CB:polymer in a weight ratio of 0.5:9.5:90. Example 7 was prepared similarly, but with a final polymer composition containing CNT:CB:polymer in a weight ratio of 0.37:9.5:90.13.

[0050] Example 2 was prepared according to Method 3 in Figure 1. A 20 wt% NC7000 in PP masterbatch was mixed with beaded CONDUCTEX 7055 ULTRA carbon black and melt-processed with virgin polypropylene (Braskem PP D115A) resin at 230°C using a twin-screw extruder (16 mm, 25:1) to yield a final polymer composition containing CNT:CB:polymer in weight ratios of 0.5:9.5:90. Examples 8 and 9 were prepared similarly, but with final polymer compositions containing CNT:CB:polymer in weight ratios of 0.75:10:89.25 and 0.30:15:84.7, respectively.

[0051] Example 3 was prepared according to Method 1 in Figure 1. In the first step, a PP-based polymer was mixed with 2.1 wt% NC7000 in a twin-screw extruder at a melt temperature of 230°C to form a first polymer mixture, which was then combined with 28.5 wt% beaded CONDUCTEX 7055 ULTRA carbon black and melt-processed in a twin-screw extruder at a melt temperature of 230°C to form a CB / CNT masterbatch. This masterbatch was let down into virgin polypropylene and melt-processed using a twin-screw extruder at 230°C to obtain a final polymer composition containing CNT:CB:polymer in a weight ratio of 0.5:9.5:90. Examples 4, 5, and 6 were prepared similarly, but with final polymer compositions containing CNT:CB:polymer in weight ratios of 0.625:11.875:87.5, 0.75:14.25:85, and 0.75:9.25:90, respectively.

[0052] Referring now to Table 1, the final polymer compositions of Examples 1-3 were the same, but the surface resistivities varied significantly. Unexpectedly, the polymer composition of Example 3, prepared using Method 1 of FIG. 1, had superior surface resistivities, orders of magnitude lower than the polymer compositions of Examples 1 and 2. Similarly, the polymer compositions of Examples 5 and 6, prepared using Method 1 of FIG. 1, had much superior surface resistivities than the polymer composition of Example 8, prepared using Method 3. Even more surprisingly, the polymer composition of Example 4, prepared using Method 1 of FIG. 1, had much superior surface resistivities than the polymer composition of Example 8, despite containing 15-20 wt. % less carbon nanotubes.

[0053] Without wishing to be bound by theory, it is believed that Method 1 (the method used in Examples 3-6) more effectively disperses the carbon nanotube and carbon black additives in the polymer matrix, thereby resulting in superior surface resistance properties even at lower filler loadings.

[0054] [Table 1]

[0055] (Aspect) It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be exemplary only, with the true scope and spirit of the invention being indicated by the following claims. Other embodiments of the present invention can include, but are not limited to, the following (although embodiments are described as "comprising," they can alternatively be described as "consist essentially of" or "consist of"):

[0056] Aspect 1. A method of making a polymer masterbatch, the method comprising: (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture; and (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch.

[0057] Embodiment 2. A method of making a polymer composition, the method comprising: (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture; (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch; and (iii) melt processing the polymer masterbatch with a bulk polymer to form a polymer composition.

[0058] Aspect 3. The method of Aspect 1 or 2, wherein the carbon nanotubes are multi-walled carbon nanotubes, single-walled carbon nanotubes, or a combination thereof.

[0059] Aspect 4. The method of any one of Aspects 1 to 3, wherein the carbon nanotubes have an average diameter in the range of 1.5 to 25 nm.

[0060] Aspect 5. The method of any one of Aspects 1 to 3, wherein the carbon nanotubes have an average diameter in the range of 9 to 15 nm.

[0061] Aspect 6. The method of any one of Aspects 1 to 5, wherein the carbon nanotubes have an average length in the range of 1 to 50 μm.

[0062] Aspect 7. The method of any one of Aspects 1 to 5, wherein the carbon nanotubes have an average length in the range of 1.5 to 15 μm.

[0063] Embodiment 8. The method of any one of embodiments 1-7, wherein the first base polymer, the second base polymer, and the bulk polymer independently comprise a thermoplastic polymer, a thermoset polymer, an elastomeric polymer, or a combination thereof.

[0064] Aspect 9. The method of any one of Aspects 1-7, wherein the first base polymer, the second base polymer, and the bulk polymer independently comprise polyethylene, polypropylene, polyamide, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene, polycarbonate, polyester, or a combination thereof.

[0065] Aspect 10. The method of any one of Aspects 1-9, wherein the melt processing in steps (i), (ii), and (iii) is independently performed in a single screw extrusion system, a twin screw extrusion system, or a Banbury mixer.

[0066] Aspect 11. The method of any one of Aspects 1 to 10, wherein the carbon nanotubes in step (i) are present as a powder.

[0067] Aspect 12. The method of any one of Aspects 1 to 11, wherein the carbon black in step (ii) is present as a powder or beads.

[0068] Aspect 13. The method of any one of Aspects 1 to 12, wherein the weight ratio of the carbon black to the carbon nanotubes in the polymer masterbatch or in the polymer composition is in the range of 70:30 to 99.5:0.5.

[0069] Aspect 14. The method of any one of Aspects 1 to 12, wherein the weight ratio of the carbon black to the carbon nanotubes in the polymer masterbatch or in the polymer composition is in the range of 85:15 to 98:2.

[0070] Aspect 15. The method of any one of Aspects 1 to 12, wherein the weight ratio of the carbon black to the carbon nanotubes in the polymer masterbatch or in the polymer composition is about 95:5.

[0071] Aspect 16. The carbon black has a viscosity of 25 to 250 mPa s, as measured in accordance with ASTM D6556 (2015). 2 16. The method of any one of embodiments 1 to 15, having a nitrogen surface area (NSA) in the range of / g.

[0072] Aspect 17. The carbon black has a viscosity of 40 to 90 mPa s, as measured in accordance with ASTM D6556 (2015). 2 16. The process of any one of aspects 1 to 15, wherein the nitrogen surface area (NSA) is in the range of / g.

[0073] Aspect 18. The carbon black has a viscosity of 45 to 250 cm as measured in accordance with ASTM D2414 (2019). 3 18. The method according to any one of aspects 1 to 17, wherein the oil absorption number (OAN) is in the range of 1 / 100g.

[0074] Aspect 19. The carbon black has a viscosity of 120 to 210 cm as measured in accordance with ASTM D2414 (2019).3 / 100g, or 120~170cm 3 18. The use according to any one of aspects 1 to 17, having an oil absorption number (OAN) in the range of 1 / 100g.

[0075] Aspect 20. The method of any one of Aspects 1 to 19, wherein 0.5 to 10 wt. % of the first polymer mixture is the carbon nanotubes.

[0076] Embodiment 21. The method of any one of embodiments 1 to 19, wherein 1 to 6 wt. % of the first polymer mixture is the carbon nanotubes.

[0077] Aspect 22. The method of any one of Aspects 1 to 21, wherein 20 to 70 wt % of the polymer masterbatch is the carbon black and the carbon nanotubes.

[0078] Aspect 23. The method of any one of Aspects 1 to 21, wherein 25 to 50 wt % of the polymer masterbatch is the carbon black and the carbon nanotubes.

[0079] Aspect 24. The method of any one of Aspects 2 to 23, wherein 1 to 30 wt. % of the polymer composition is the carbon black and the carbon nanotubes.

[0080] Aspect 25. The method of any one of Aspects 2 to 23, wherein 5 to 15 weight percent of the polymer composition is the carbon black and the carbon nanotubes.

Claims

1. 1. A method for producing a polymer masterbatch, comprising: (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture; and (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch;

2. 1. A method for producing a polymer composition, comprising: (i) melt processing a first base polymer and carbon nanotubes to form a first polymer mixture; (ii) melt processing the first polymer mixture, carbon black, and optionally a second base polymer to form a polymer masterbatch; and (iii) melt processing the polymer masterbatch with a bulk polymer to form a polymer composition;

3. The method of claim 1 or 2, wherein the carbon nanotubes are multi-walled carbon nanotubes, single-walled carbon nanotubes, or a combination thereof.

4. The method according to any one of claims 1 to 3, wherein the carbon nanotubes have an average diameter in the range of 1.5 to 25 nm.

5. The method according to any one of claims 1 to 3, wherein the carbon nanotubes have an average diameter in the range of 9 to 15 nm.

6. The method of any one of claims 1 to 5, wherein the carbon nanotubes have an average length in the range of 1 to 50 μm.

7. The method of any one of claims 1 to 5, wherein the carbon nanotubes have an average length in the range of 1.5 to 15 μm.

8. 8. The method of any one of claims 1 to 7, wherein the first base polymer, the second base polymer, and the bulk polymer independently comprise a thermoplastic polymer, a thermoset polymer, an elastomeric polymer, or a combination thereof.

9. 8. The method of any one of claims 1 to 7, wherein the first base polymer, the second base polymer, and the bulk polymer independently comprise polyethylene, polypropylene, polyamide, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene, polycarbonate, polyester, or a combination thereof.

10. 10. The method of any one of claims 1 to 9, wherein the melt processing in steps (i), (ii), and (iii) is independently carried out in a single screw extrusion system, a twin screw extrusion system, or a Banbury mixer.

11. The method of any one of claims 1 to 10, wherein the carbon nanotubes in step (i) are present as a powder.

12. 12. The method of any one of claims 1 to 11, wherein the carbon black in step (ii) is present as a powder or beads.

13. The carbon black has a viscosity of 25 to 250 m as measured in accordance with ASTM D6556 (2015). ２ 13. The method of any one of claims 1 to 12, wherein the carbon nanotube has a nitrogen surface area (NSA) in the range of 1 / g.

14. The carbon black has a viscosity of 40 to 90 m, as measured in accordance with ASTM D6556 (2015). ２ 13. The method of any one of claims 1 to 12, wherein the carbon nanotube has a nitrogen surface area (NSA) in the range of 1 / g.

15. The carbon black has a viscosity of 45 to 250 cm as measured in accordance with ASTM D2414 (2019). ３ 15. The method of any one of claims 1 to 14, wherein the oil absorption number (OAN) is in the range of 1 / 100g.

16. The carbon black has a viscosity of 120 to 210 cm as measured in accordance with ASTM D2414 (2019). ３ / 100g, or 120-170cm ３ 15. The method of any one of claims 1 to 14, wherein the oil absorption number (OAN) is in the range of 1 / 100g.

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