Highly Electrically Conductive Compounds for High Temperature Battery Electrode Plates

Abstract

The thermoplastic composition comprises: about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer; and a combination of at least two carbon-based fillers, including a first carbon-based filler comprising graphite, and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof. The first carbon-based filler comprises graphite in an amount of about 30 wt% to about 59 wt%. The composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991. The total weight percentage values ​​of all components do not exceed 100 wt%, and all weight percentage values ​​are based on the total weight of the composition. A method of making a thermoplastic composition is also described, including forming the composition using a PPS-based masterbatch.

Description

[Technical field]

[0001] The present disclosure relates to polyphenylene sulfide (PPS)-based polymers, and in particular to PPS-based polymers containing at least two carbon-based fillers that have enhanced electrical conductivity properties and are suitable for use in battery electrode plates. [Background technology]

[0002] The search for carbon-plastic electrode compositions for use as electrode plates in zinc bromide batteries began in the late 1970s. U.S. Patent No. 4,169,816 ("the '816 patent") by Exxon Research & Engineering, for example, describes a homogeneous blend of a crystalline polypropylene-ethylene copolymer, electrically conductive carbon black, a small amount of silica, and a fibrous reinforcement selected from carbon fiber and a mixture of carbon and glass fibers. The composition is reported to have excellent strength, good extrudability, excellent volume resistivity (1 ohm.cm), and good impermeability. The Exxon patent states that to impart electrical conductivity, it is desirable for the composition to contain at least 15 parts by weight of finely divided conductive carbon powder per 100 parts by weight (pph) of copolymer. The patent also states that it is desirable not to employ 35 pph of conductive carbon; otherwise, the composition will be too brittle and difficult to extrude into thin, nonporous sheets. Also, increasing the amount of carbon to about 35 pph tends to increase the permeability of thin sheets made from such compositions to liquids, such as bromine. Finely divided conductive carbon black has a permeability of about 500 m 2 / g, such as those manufactured under the trademark Ketjenblack EC.

[0003] Johnson Controls began investigating plastic-carbon electrodes in the 1990s, reporting that ethylene-propylene (EP) copolymer-based electrodes developed by Exxon were susceptible to oxidative attack, swelling, and warping. They explained that the mechanism behind bromide attack was the vulnerability of tertiary hydrogens in the backbone of the propylene chain. To overcome this issue, Johnson Controls chose HDPE homopolymer, which largely, if not completely, removes the tertiary hydrogens on the backbone. Johnson Controls reported positive results in aging studies with base polymer substitutions, with HDPE outperforming EP copolymers.

[0004] Globe-Union Inc (a subsidiary of Johnson Controls) patented their HDPE-based carbon-plastic electrodes in December 1992. U.S. Patent No. 5,173,362 ("the '362 patent") describes compositions for electrode systems, particularly those used in bipolar electrodes in zinc-bromine batteries. These compositions preferably contained carbon black as a conductive filler in a polymeric matrix, along with a reinforcing material such as glass fiber. Warping of zinc-bromine electrodes, observed in the prior art and believed to be caused by physical stretching of the electrode due to bromine absorption by the electrode material, has been substantially eliminated in the compositions and fabrication process described in this disclosure. In this patent, the material is prepared using a lamination process known as glass mat reinforced thermoplastic technology, or in a different embodiment, the substrate is made using a slurry process. Bromination, unlike chlorination, is highly selective to the chemistry of the polymer matrix used, with tertiary hydrogens in polypropylene reacting approximately 20,000 times faster with bromine than secondary hydrogens in polyethylene. Three types of carbon black were used in the compositions of this disclosure, with the grade of Ketjenblack EC 300J providing the best combination of electrical conductivity and processability properties for the amount of carbon used. The '362 patent describes a wide range of carbon black and fiber loadings ranging from 5-40 wt% and 10-70 wt%, respectively, but also exemplifies a composition having a carbon loading of 18 wt% (the same as Exxon), so the carbon and fiber loadings used in the Johnson Controls patent are closer to those disclosed in the '816 patent.

[0005] SABIC's U.S. Provisional Patent Application No. 63 / 162,615 (the "615" application), entitled "Electrically Conductive Compositions for Battery Electrode Plates," relates to thermoplastic compositions having high electrical conductivity, and in particular to polyethylene-based compositions containing graphite filler and carbon black powder suitable for use in battery electrode applications. The materials of the disclosure exhibited good chemical resistance and electrical conductivity, but were difficult to extrude into relatively thin sheets due to the high loadings of carbon filler used. Also, sheets made from the compositions of the disclosure could not be used above about 60° C. due to the limited heat resistance of the polyethylene polymer used as the continuous matrix in these formulations.

[0006] None of these prior attempts have demonstrated the balance of electrical conductivity, chemical resistance, and processability required to manufacture thin sheets for battery electrode plates using conventional extrusion or molding processes.

[0007] These and other shortcomings are addressed by aspects of the present disclosure. Summary of the Invention [Means for solving the problem]

[0008] The disclosed embodiments relate to a thermoplastic composition comprising: about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer; and at least two carbon-based fillers, including a first carbon-based filler comprising graphite, and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof. The first carbon-based filler comprises graphite in an amount of about 30 wt% to about 59 wt%. The composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991. The total weight percentage values ​​of all components do not exceed 100 wt%, and all weight percentage values ​​are based on the total weight of the composition.

[0009] A further embodiment of the disclosure relates to a method of forming a composition comprising about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer in combination with at least two carbon-based fillers, the method comprising: combining the at least one PPS polymer with the at least two carbon-based fillers to form a mixture; and extruding the mixture to form the composition. The at least two carbon-based fillers include a first carbon-based filler comprising graphite and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof. The graphite is present in an amount of about 30 wt% to about 59 wt%. The composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991. The total weight percentage values ​​of all components do not exceed 100 wt%, and all weight percentage values ​​are based on the total weight of the composition.

[0010] The drawings are not necessarily drawn to scale, and like reference numbers may describe like components in different figures. Like reference numbers with different letter suffixes may represent different instances of like components. The drawings illustrate generally, by way of example, but not by way of limitation, various aspects discussed in the present specification. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of an apparatus used to determine shielding effectiveness (SE), according to an embodiment of the disclosure. [Diagram 2] 1 is a graph of SE as a function of frequency, for example, for example compositions Ex2.1 and Ex2.2, in accordance with an embodiment of the disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present disclosure relates to highly loaded plastic materials used to replace metallic electrode plates in flow batteries, such as zinc bromide and vanadium redox flow batteries. These materials include at least one polyphenylene sulfide (PPS) and a mixture of synthetic graphite, carbon nanotubes, and conductive carbon powders (e.g., carbon black). The compositions according to the disclosed embodiments include high electrical conductivity, good thermal and chemical resistance, and processability into thin plastic sheets using traditional polymer processing methods. In a further embodiment, the compositions can replace metal and metallized polymeric materials in EMI shielding of coaxial cables, cell phones, computers, laptops, monitors, and other sensitive electronic devices that require isolation from external electromagnetic fields.

[0013] 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, unless otherwise specified, or to particular reagents, unless otherwise specified, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0014] Various combinations of elements of the present disclosure are encompassed by the present disclosure, for example combinations of elements from dependent claims that are dependent on the same independent claim.

[0015] Further, it will be understood that, unless expressly stated otherwise, it is in no way intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, unless a method claim actually recites the order in which its steps are to be followed, or unless the claim or specification otherwise specifically indicates that the steps are limited to a particular order, no order is intended to be inferred in any respect. This applies to any possible non-express basis for interpretation, including logical considerations regarding the sequence of steps or the flow of operations; the plain meaning derived from grammatical constructions and punctuation; and the number or type of aspects described herein.

[0016] All publications mentioned herein are incorporated herein by reference and are cited in connection with the methods and / or materials disclosed and described.

[0017] definition It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein and in the claims, the term "comprising" can include "consisting of" and "consisting essentially of" embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In this specification and in the claims that follow, reference will be made to several terms that are intended to be defined herein.

[0018] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a polyphenylene sulfide polymer" includes a mixture of two or more polyphenylene sulfide polymers.

[0019] As used herein, the term "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like.

[0020] Ranges can be expressed herein as from one value (a first value) to another value (a second value). When such a range is expressed, the range, in some embodiments, includes one or both of the first and second values. Similarly, when values ​​are expressed as approximations, it will be understood that the particular value forms another embodiment by use of the antecedent "about." It will further be understood that the endpoints of each range are valid both in relation to the other endpoint, and independently of the other endpoint. It will also be understood that there are multiple values ​​disclosed herein, and that each value is also disclosed herein as "about" that value, in addition to the particular value itself. For example, if the value "10" is disclosed, then "about 10" is also disclosed. It will also be understood that each unit between two particular units is also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0021] As used herein, the terms "about" and "at or near" mean that the quantity or value in question can be the specified value, approximately the specified value, or about the specified value. As used herein, unless otherwise indicated or inferred, the value is generally understood to be a variation of ±10% of the nominal value indicated. The term is intended to convey that the equivalent results or effects described in the claims are promoted by such similar values. That is, it is understood that the amounts, sizes, formulations, parameters, and other quantities and characteristics are not and do not have to be exact, but can be approximate and / or larger or smaller as desired, reflecting tolerances, conversion factors, rounding, measurement errors, and the like, and other factors known to those skilled in the art. In general, the amounts, sizes, formulations, parameters, or other quantities or characteristics are "about" or "approximate", whether or not they are expressly defined as such. When "about" is used before a quantitative value, the parameter is also understood to include the specific quantitative value itself, unless otherwise specifically defined.

[0022] Disclosed are the components used to prepare the disclosed compositions 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 is understood that each of the various individual and collective combinations and permutations of these compounds are specifically contemplated and described herein, although they may not be expressly disclosed as specifically referring to each of them. For example, when a particular compound is disclosed and discussed, and multiple modifications that can be made to multiple molecules that include the compound are discussed, what is specifically contemplated is each and every combination and permutation of the compound and modifications that are possible, unless otherwise specifically indicated to the contrary. Thus, when a class of molecules A, B, and C is disclosed, as well as a class of molecules D, E, and F, and an example of a combination molecule AD is disclosed, this means that each is individually and collectively contemplated, even if each is not individually mentioned, and the combinations AE, AF, BD, BE, BF, CD, CE, and CF are considered to be disclosed. Similarly, any subsets or combinations of these are disclosed. Thus, for example, the subgroups AE, BF, and CE may be considered disclosed. This concept applies to all aspects of this application, including but not limited to steps in methods of making and using the disclosed compositions. Thus, where there are various additional steps that can be performed, it is understood that each of these additional steps can be performed with any specific aspect or combination of aspects of the disclosed methods.

[0023] In this specification and the appended claims, reference to parts by weight of a particular component or ingredient in a composition or article indicates the weight relationship, expressed in parts by weight, between that component or ingredient and the other components or ingredients in the composition or article. Thus, in a compound containing 2 parts by weight of component X and 5 parts by weight of component Y, X and Y are present in a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the compound.

[0024] Weight percentages of components are based on the total weight of the formulation or composition in which the component is included, unless specifically stated to the contrary.

[0025] As used herein, the terms "weight percent," "wt%," and "wt.%" can be used interchangeably and refer to the weight percent of a given component based on the total weight of the composition, unless otherwise specified. That is, all wt% values ​​are based on the total weight of the composition, unless otherwise specified. It is to be understood that the sum of the wt% values ​​of all components in a disclosed composition or formulation equals 100.

[0026] Unless otherwise stated herein to the contrary, all testing standards are the latest standards in effect at the time of filing this application.

[0027] Each of the raw materials used in the example compositions and / or comparative compositions described herein is commercially available and / or its method of manufacture is known to those of ordinary skill in the art.

[0028] It is understood that the compositions disclosed herein have specific functions. Disclosed herein are specific structural requirements that perform the disclosed functions, and it is understood that there are various structures that can perform the same functions associated with the disclosed structures, and that these structures typically achieve the same results.

[0029] thermoplastic composition Disclosed embodiments relate to highly loaded plastic materials suitable for replacing titanium in electrode plates of zinc bromide flow batteries. In some embodiments, these materials include at least one polyphenylene sulfide (PPS) and a mixture of synthetic graphite, carbon nanotubes, and conductive carbon powder (e.g., carbon black) in different ratios. The use of carbon nanotubes in these compositions allows for a reduced dosage of graphite and carbon powder, producing materials with similar electrical conductivity but improved flow compared to compositions containing only graphite and carbon powder. Three desirable properties for such compounds include high electrical conductivity, chemical resistance, and processability into thin plastic sheets using conventional polymer processing methods. Polyphenylene sulfide (PPS) compounds suitable for use in the disclosed embodiments include, but are not limited to, FORTRON® 0203 and FORTRON® 0205, both of which are available from Celanese. FORTRON® 0203 is a low viscosity, unfilled PPS resin that flows very easily in compounding operations. FORTRON® 0205 is an unfilled, mid-viscosity range PPS resin intended for compounding with a variety of fillers. These two grades demonstrate excellent chemical resistance and thermal stability, exhibiting melting temperatures of about 280°C and glass transition temperatures of about 90°C. Polyphenylene sulfide (PPS) is a high temperature semi-crystalline polymer with a symmetrical rigid backbone containing repeating aromatic rings linked by sulfides. PPS offers high thermal stability, very high chemical resistance, stiffness, strength, and creep resistance.

[0030] The addition of glass fibers and glass fiber / mineral blends to standard PPS allows for service temperatures up to about 240°C, very good resistance to chemicals and solvents, inherent flame retardancy, very low moisture absorption, and excellent creep resistance even at high temperatures. According to Celanese, the chemical structure of PPS provides excellent chemical and heat resistance, insolubility in all known solvents below 200°C (392°F), and very good stability in both typical and alternative motor fuels.

[0031] Carbon nanotubes suitable for use in the disclosed embodiments may be added in the form of custom-made PPS-based masterbatches. Such masterbatches are available from NANOCYL under the trade name PLASTICYL™. These include 10 wt% NC7000™ multi-walled carbon nanotubes produced by a catalytic chemical vapor deposition (CCVD) process. Carbon nanotubes are tubular materials containing carbon atoms with nanometer-sized diameters. Carbon nanotubes appear as black powders, but at the nanoscale level have a spaghetti-like structure. Exemplary carbon nanotubes suitable for the disclosed embodiments have an average diameter of about 10 nanometers (nm), an average length of about 1.5 microns (µm), and a density of about 250-300 square meters per gram (m 2 / gr) and approximately 10 -4 It has a volume resistivity in ohm-centimeters (ohm.cm).

[0032] Carbon nanotubes have a high aspect ratio that results in a relatively low amount of nanotubes required to achieve a particular electrical conductivity. Furthermore, carbon nanotubes typically increase the viscosity of a composition more than carbon powder at an equal loading, but a much lower amount of nanotubes is typically required. Carbon nanotubes also offer high electrical conductivity, good processability, retention of mechanical properties, high reusability, and thermal dissipation factor properties.

[0033] Specific embodiments of the disclosure relate to a thermoplastic composition comprising: about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer; and a combination of at least two carbon-based fillers, including a first carbon-based filler comprising graphite, and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof. The first carbon-based filler comprises graphite in an amount of about 30 wt% to about 59 wt%. The composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991. The total weight percentage values ​​of all components do not exceed 100 wt%, and all weight percentage values ​​are based on the total weight of the composition.

[0034] In certain embodiments, the composition comprises at least 35 wt% PPS polymer, or at least 37 wt%, or at least 39 wt%, or at least 41 wt%, or at least 43 wt%, or at least 44 wt%, or at least 45 wt%, or at least 46 wt%, or at least 47 wt%, or at least 48 wt%, or at least 49 wt%, or at least 50 wt% of at least one PPS polymer. In further embodiments, the composition comprises at most 65 wt%, or at most 64 wt%, or at most 63 wt%, or at most 62 wt%, or at most 61 wt%, or at most 60 wt%, or at most 59 wt%, or at most 58 wt%, or at most 57 wt%, or at most 56 wt%, or at most 55 wt% of at least one PPS polymer.

[0035] In some embodiments, graphite is present in an amount of at least 30 wt%, or at least 31 wt%, or at least 32 wt%, or at least 33 wt%, or at least 34 wt%, or at least 35 wt%, or at least 36 wt%, or at least 37 wt%, or at least 38 wt%, or at least 39 wt%, or at least 40 wt%. In other embodiments, graphite is present in an amount of at most 59 wt%, or at most 58 wt%, or at most 57 wt%, or at most 56 wt%, or at most 55 wt%, or at most 54 wt%, or at most 53 wt%, or at most 52 wt%, or at most 51 wt%, or at most 50 wt%.

[0036] In certain embodiments, the second carbon-based filler comprises carbon powder in an amount of about 2 wt% to about 8 wt%. In certain embodiments, the second carbon-based filler comprises carbon powder in an amount of about 2 wt% to about 8 wt%, or 2 wt% to 8 wt%, or 3 wt% to 8 wt%, or 4 wt% to 8 wt%, or 5 wt% to 8 wt%, or 6 wt% to 8 wt%, or 2 wt% to 7 wt%, or 2 wt% to 6 wt%, or 2 wt% to 5 wt%.

[0037] In other embodiments, the second carbon-based filler comprises carbon nanotubes in an amount of about 2 wt% to about 6 wt%. In further embodiments, the second carbon-based filler comprises carbon nanotubes in an amount of about 2 wt% to about 6 wt%, or 2 wt% to 6 wt%, or 3 wt% to 6 wt%, or 4 wt% to 6 wt%, or 2 wt% to 5 wt%.

[0038] In certain embodiments, the compositions exhibit a volume electrical resistivity of less than 4 ohm.cm as measured by ASTM D991. In further embodiments, the compositions exhibit a volume electrical resistivity of less than 3 ohm.cm, or less than 2 ohm.cm, or less than 1 ohm.cm, or less than 0.9 ohm.cm, or less than 0.8 ohm.cm, or less than 0.7 ohm.cm, or less than 0.6 ohm.cm, or less than 0.5 ohm.cm, or less than 0.4 ohm.cm, or less than 0.3 ohm.cm, or less than 0.2 ohm.cm, or less than 0.1 ohm.cm as measured by ASTM D991.

[0039] In further embodiments, the composition has a through-plane thermal conductivity of at least 0.6 Watts per meter-Kelvin (W / mK) as determined in accordance with ISO 22007-2. In some embodiments, the composition has a through-plane thermal conductivity of at least 0.7 W / mK, or at least 0.8 W / mK, or at least 0.9 W / mK, or at least 1.0 W / mK, or at least 1.1 W / mK, or at least 1.2 W / mK, or at least 1.3 W / mK, or at least 1.4 W / mK, or between 0.6 and 1.5 W / mK.

[0040] The composition may, in certain embodiments, have an in-plane thermal conductivity of at least 5.0 W / mK as determined according to ISO 22007-2. In further embodiments, the composition has an in-plane thermal conductivity of at least 5.4 W / mK, or at least 6 W / mK, or at least 7 W / mK, or at least 8 W / mK, or at least 9 W / mK, or at least 10 W / mK, or at least 11 W / mK, or at least 12 W / mK, or at least 13 W / mK, or at least 14 W / mK, or at least 15 W / mK, or at least 16 W / mK, or from 5 to 20 W / mK.

[0041] The composition may have a bulk thermal conductivity of at least 1.8 W / mK in some embodiments. In further embodiments, the composition has a bulk thermal conductivity of at least 2.0 W / mK, or at least 2.5 W / mK, or at least 3.0 W / mK, or at least 3.5 W / mK, or at least 4.0 W / mK, or at least 4.5 W / mK, or from 1.8 to 5 W / mK.

[0042] In specific embodiments, the composition has a far-field electromagnetic shielding effectiveness (SE) of at least 80 decibels (dB) at frequencies between 3 GHz and 6 GHz, as tested in accordance with ASTM D4935. In certain embodiments, the composition has a far-field electromagnetic SE of at least 85 dB, or at least 90 dB, or at least 95 dB, or at least 100 dB at frequencies between 3 GHz and 6 GHz.

[0043] In some embodiments, the composition includes at least one additional additive, which may include, but is not limited to, an acid scavenger, an anti-drip agent, an antioxidant, an antistatic agent, a chain extender, a colorant, a release agent, a flow promoter, a lubricant, a plasticizer, a reaction stopper, a flame retardant, a UV reflective additive, an impact modifier, a blowing agent, a reinforcing agent, or a combination thereof.

[0044] In another embodiment, the composition comprises graphite, carbon powder, and carbon nanotubes.

[0045] Method of production One or any of the aforementioned components described herein may first be dry blended with each other or with any combination of the aforementioned components, and then fed into the extruder from a single or multiple feeder, or fed separately into the extruder from a single or multiple feeder. The fillers used in the disclosure may also be first processed into a masterbatch and then fed into the extruder. The components may be fed into the extruder from the throat hopper, or any side feeder.

[0046] The extruder used in the disclosure may have a single screw, multiple screws, intermeshing co-rotating or counter-rotating screws, non-intermeshing co-rotating or counter-rotating screws, reciprocating screws, screws with pins, screws with screens, barrels with pins, rolls, rams, helical rotors, co-kneaders, disc-pack processors, various other types of extrusion equipment, or combinations comprising at least one of the foregoing.

[0047] The components may also be mixed together and then melt blended to form the thermoplastic composition. Melt blending the components involves the use of shear forces, extensional forces, compression forces, ultrasonic energy, electromagnetic energy, thermal energy, or a combination comprising at least one of the foregoing forms of force or energy.

[0048] The barrel temperature of the extruder during compounding may be set at a temperature at which at least a portion of the polymer reaches a temperature about or above the melting temperature if the resin is a crystalline or semi-crystalline organic polymer, or at the pour point (e.g., glass transition temperature) if the resin is an amorphous resin.

[0049] The mixture containing the aforementioned components may be subjected to multiple blending and forming steps as required. For example, the thermoplastic composition may first be extruded and formed into pellets. The pellets may then be fed to a molding machine where they may be formed into any desired shape or product. Alternatively, the thermoplastic composition discharged from a single melt blender may be formed into sheets or strands and subjected to post-extrusion steps such as annealing, uniaxial or biaxial stretching, etc.

[0050] The temperature of the melt in this process may be kept as low as possible in some embodiments to avoid excessive thermal degradation of the components. In certain embodiments, the melt temperature is kept between about 230°C and about 350°C, although higher temperatures may be used, provided that the residence time of the resin in the processing equipment is kept relatively short. In some embodiments, the melt-processed composition leaves the processing equipment, such as an extruder, through small exit holes in a die. The resulting strands of molten resin may be cooled by passing them through a water bath. The cooled strands may be cut into pellets for packaging and further handling.

[0051] In a specific embodiment, a method of forming a composition includes a combination of about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer and at least two carbon-based fillers, the method including: combining the at least one PPS polymer and the at least two carbon-based fillers to form a mixture; and extruding the mixture to form the composition. The at least two carbon-based fillers include a first carbon-based filler including graphite and a second carbon-based filler including carbon powder, carbon nanotubes, or a combination thereof. The graphite is present in an amount of about 30 wt% to about 59 wt%. The composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991. The total weight percentage values ​​of all components does not exceed 100 wt%, and all weight percentage values ​​are based on the total weight of the composition.

[0052] In certain embodiments, the one or more carbon-based fillers are provided in the form of a PPS-based masterbatch composition.

[0053] Thermoplastic compositions formed according to these methods may contain the components and amounts described herein and may have one or more of the properties described herein.

[0054] Articles of manufacture In certain aspects, the present disclosure relates to shaped, formed, or molded articles comprising the thermoplastic composition.The thermoplastic composition can be molded into useful shaped articles by various means, such as injection molding, extrusion, rotational molding, blow molding, and thermoforming, to form articles and structural components of, for example, personal or commercial electronic devices, including mobile phones, tablet computers, personal computers, notebook and portable computers, and other such devices, medical applications, RFID applications, automotive applications, and the like.In further aspects, the article is extruded.In even further aspects, the article is injection molded.

[0055] In certain embodiments, the article is an electrically conductive electrode plate in a flow battery, a thermally conductive plate in a heat exchanger used to transfer heat between two fluids, or an enclosure or package that protects electronic devices used in medical, military, and aerospace electronics from the damaging effects of electromagnetic radiation.

[0056] In some embodiments, the thermoplastic composition may be extruded into a sheet. In further embodiments, the thermoplastic composition may be extruded, injection molded, compression molded, injection compression molded, or some combination of these processes. Sheets of various thicknesses may be formed. In some embodiments, the composition may be formed into sheets having a thickness of up to 3 mm or more. In further embodiments, thin sheets of 0.020 inches to 0.060 inches may be formed. In specific embodiments, the thin sheets have a thickness of 0.125 inches or less. As discussed herein, extrusion may be a desired process for making these thin sheets. Thin sheets having a thickness of 0.125 inches or less may be suitable for use in flow batteries (e.g., bipolar electrode plates in such batteries) in some embodiments. For other applications, such as the exemplary heat exchanger plates and housings for automotive radar sensors, even thicker sheets may be desirable.

[0057] Various combinations of elements of the present disclosure are encompassed by the present disclosure, for example combinations of elements from dependent claims that are dependent on the same independent claim.

[0058] Aspects of the Disclosure In various aspects, the present disclosure relates to and includes at least the following aspects:

[0059] Aspect 1. about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer; A combination of at least two carbon-based fillers comprising a first carbon-based filler comprising graphite and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof; A thermoplastic composition comprising, consisting of, or consisting essentially of: the first carbon-based filler comprises graphite in an amount of about 30 wt % to about 59 wt %; the composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991; A thermoplastic composition, wherein the combined weight percentage of all components does not exceed 100 wt%, all weight percentages being based on the total weight of the composition.

[0060] Aspect 2. 2. The thermoplastic composition of embodiment 1, wherein the second carbon-based filler comprises carbon powder in an amount between about 2 wt.% and about 8 wt.%.

[0061] Aspect 3. 3. The thermoplastic composition of embodiment 1 or 2, wherein the second carbon-based filler comprises carbon nanotubes in an amount between about 2 wt % and about 6 wt %.

[0062] Aspect 4. Aspect 4. The thermoplastic composition of any of aspects 1-3, wherein the composition exhibits a volume electrical resistivity of less than 1 ohm.cm as measured by ASTM D991.

[0063] Aspect 5. 5. The thermoplastic composition of any of the preceding embodiments, wherein the composition has a through-plane thermal conductivity, determined in accordance with ISO 22007-2, of at least 0.8 W / mK, or an in-plane thermal conductivity, determined in accordance with ISO 22007-2, of at least 5.4 W / mK.

[0064] Aspect 6. 6. The thermoplastic composition of any of the preceding embodiments, wherein the composition has a bulk thermal conductivity of at least 1.8 W / mK.

[0065] Aspect 7. 7. The thermoplastic composition of any of the preceding claims, wherein the composition has a far-field electromagnetic shielding effectiveness (SE) of at least 80 decibels (dB) at a frequency of 3 GHz to 6 GHz, tested in accordance with ASTM D4935.

[0066] Aspect 8. The thermoplastic composition of any of the preceding embodiments, wherein the composition comprises at least one further additive.

[0067] Aspect 9. The thermoplastic composition of embodiment 8, wherein the at least one additional additive comprises an acid scavenger, an anti-drip agent, an antioxidant, an antistatic agent, a chain extender, a colorant, a release agent, a flow promoter, a lubricant, a plasticizer, a reaction terminator, a flame retardant, a UV reflective additive, an impact modifier, a blowing agent, a reinforcing agent, or a combination thereof.

[0068] Aspect 10. 10. The thermoplastic composition of any one of embodiments 1 to 9, wherein the composition comprises graphite, carbon powder, and carbon nanotubes.

[0069] Aspect 11. An extruded sheet comprising the composition of any one of embodiments 1 to 10.

[0070] Aspect 12. 12. The extruded sheet of embodiment 11, wherein the sheet has a thickness of 0.125 inch or less.

[0071] Aspect 13. 1. A method for forming a composition comprising, consisting of, or consisting essentially of about 35 wt% to about 65 wt% of at least one polyphenylene sulfide (PPS) polymer and a combination of at least two carbon-based fillers, comprising: combining at least one PPS polymer and at least two carbon-based fillers to form a mixture; extruding the mixture to form a composition; the at least two carbon-based fillers comprise a first carbon-based filler comprising graphite and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof; Graphite is present in an amount of about 30 wt% to about 59 wt%, the composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991; The method wherein the total weight percentage of all components does not exceed 100 wt%, and all weight percentages are based on the total weight of the composition.

[0072] Aspect 14. 14. The method of embodiment 13, wherein the one or more carbon-based fillers are provided in the form of a PPS-based masterbatch composition.

[0073] Aspect 15. 11. An article comprising the thermoplastic composition of any of the preceding embodiments, wherein the article comprises: an electrically conductive electrode plate of a flow battery; a thermally conductive plate of a heat exchanger used to transfer heat between two fluids; or an enclosure or packaging that protects electronic devices from electromagnetic radiation used in medical, military, or aerospace electronics. EXAMPLES

[0074] The following examples are presented to provide those skilled in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and / or methods claimed herein are made and evaluated, and are intended to be purely illustrative and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but it is desirable to account for some errors and deviations. Unless otherwise indicated, parts are parts by weight, temperature is in ° C. or is at ambient temperature, and pressure is at or near atmospheric pressure. Percentages referring to compositions are in wt% unless otherwise indicated.

[0075] There are numerous variations and combinations of reaction conditions, such as component concentrations, desired solvents, solvent mixtures, temperatures, pressures, and other reaction ranges and conditions that can be used to optimize the purity and yield of the products obtained from the described processes. Optimization of such process conditions will require no more than reasonable and routine experimentation.

[0076] The PPS-based masterbatch used in the disclosed embodiments was diluted with virgin, unfilled polyphenylene sulfide resin (e.g., FORTRON® 0203B6). FORTRON® 0203B6 is a low viscosity, unfilled grade that flows very easily in compounding operations. The compositions according to the embodiments contained about 45 wt% to about 65 wt% of the masterbatch; the amount of virgin PPS resin was kept at 15 wt% for most of the conditions examined. These polymer / masterbatch ratios produced materials with about 4.5 wt% to about 6.5 wt% of carbon nanotubes in the final formulation. The degree of crystallinity of both PPS resins was examined by DSC and found to be 63.8% for FORTRON® 0203B6 and 56.6% for FORTRON® 0205B4. These values ​​were calculated using the heat of fusion, which was equal to 48.83 Joules per gram (J / g) for FORTRON® 0203B6 and 43.30 J / g for FORTRON® 0205B4, and the theoretical enthalpy of fusion, obtained from the literature, was 76.5 J / g for PPS with 100% crystallinity.

[0077] Some of the PPS-based compositions described herein were injection molded into 150 millimeter (mm) x 108 mm plaques with thicknesses of 2.50 mm and 2.00 mm; the plaques were tested for physical and electrical conductivity properties. The graphite used in the compositions is a highly crystalline material of high purity, which is produced at extremely high temperatures to evaporate impurities such as metal oxides, sulfur, iron, aluminum, and many others to give greater than 99% pure carbon synthetic graphite with particle sizes ranging from less than 1 micron to hundreds of microns. The carbon powder (carbon black) used in the compositions has a primary / elementary particle size of a few tens to 50 nanometers (nm), with strong aggregates hundreds of nanometers in size, and larger aggregates of 100 to 200 microns.

[0078] Example 1 The compositions were formulated, injection molded and extruded into plaques, and certain properties were tested according to Table 1. [Table 1]

[0079] All compositions were injection moldable under conventional molding conditions. All compositions, except for comparative composition C1.7, were extrudable at conventional extrusion temperatures (<350 degrees Celsius (°C)) and pressures (<200 pounds per square inch (PSI) for Ex1.6 and <35 psi for Ex1.2-Ex1.5). Composition C1.7 was difficult to extrude, requiring an extrusion melt temperature of about 367°C and a die melt pressure of about 600 psi. Considering these required extrusion conditions, composition C1.7, containing an excessive amount of total carbon filler of 60 wt%, is not practical for injection molding articles.

[0080] From the results in Table 1, it was observed that the comparative composition C1.1 having less than 35 wt.% carbon-based filler with 30 wt.% graphite had a high volume electrical resistivity of greater than 5 ohm-centimeters (ohm-cm) determined in accordance with ASTM D991. The composition also had low thermal conductivity properties, i.e., a bulk thermal conductivity of less than 0.6 watts per meter Kelvin (W / mK) in the through-plane direction, less than 5.4 W / mK in the in-plane direction, and less than 1.8 W / mK. The bulk thermal conductivity was calculated as the square root of the product of the through-plane thermal conductivity and the in-plane thermal conductivity. In contrast, example compositions Ex1.2 to Ex1.6, having at least 35 wt% carbon-based filler with at least 30 wt% graphite, had relatively low volume resistivity (less than 5 ohms.com), high through-plane thermal conductivity (greater than 0.6 W / mK), high in-plane thermal conductivity (greater than 5.4 W / mK), and high bulk conductivity (greater than 1.8 W / mK). The thermal conductivity of these materials was measured according to ISO 22007-2 for through-plane and in-plane conductivity (measured on 60 mm x 60 mm x 3 mm plaques). The bulk thermal conductivity was calculated from the through-plane and in-plane thermal conductivity values.

[0081] Some of the example compositions exhibited a surface electrical resistivity of less than 4 ohms / sq, as determined according to ASTM D257, and a total shielding effectiveness of at least 35 dB, as determined according to SABIC's modified ASTM D4935 test method based on the so-called Faradex™ instrument. The modified ASTM D4935 method measures the electrical conductivity of a material using a pulsed magnetic field that penetrates a conductive material. This conductivity measurement system reports both the sheet resistance and the far-field shielding. The far-field electromagnetic shielding in dB is calculated from the sheet resistance measured in ohms. The test requires the evaluation of at least five plaques with dimensions of 3 inches by 5 inches. It was observed that for carbon-based materials the Faradex™ instrument is less reliable than the standard method, because the modified method of calculating the SE only takes into account the reflected (and not absorbed) portion of the radiation.

[0082] Example 2 The compositions were formulated, injection molded and extruded into plaques, and certain properties were tested according to Table 2. [Table 2]

[0083] All compositions were injection moldable using conventional molding conditions. From the results in Table 2, it was observed that example compositions Ex2.1-Ex2.3 had volume electrical resistivities of less than 0.3 ohm.cm (0.180 ohm.cm, 0.202 ohm.cm, and 0.089 ohm.cm, respectively) determined in accordance with ASTM D991. Also, the through-plane thermal conductivity (W / mK) varied between 1.09 and 1.42, the in-plane thermal conductivity (W / mK) varied between 11.12 and 16.90, and the bulk thermal conductivity (W / mK) varied between 3.97 and 4.54.

[0084] Shielding effectiveness properties were also determined for compositions Ex2.1 and Ex2.2 in accordance with ASTM D4935 using the test apparatus of FIG. 1. Specifically, the far-field electromagnetic shielding effectiveness (SE) was evaluated for the frequency range from about 30 megahertz (MHz) to about 6 gigahertz (GHz). The SE results are shown in FIG. 2. The results show that compositions Ex2.1 and Ex2.2 have similar shielding effectiveness. Specifically, both samples were observed to have an SE of at least 90 dB at frequencies above 3 GHz.

[0085] Example 3 The compositions were formed, injection molded and extruded into plaques and tested for certain properties according to Table 3: [Table 3]

[0086] Comparative composition C3.1 was not extrudable; it was too viscous and blocked the extruder die head after a short time. Example compositions Ex3.2 and Ex3.3 were extrudable at conventional extrusion temperatures and pressures.

[0087] The volume electrical resistivities of compositions Ex3.2 and Ex3.3 were measured in accordance with ASTM D991 and the results are shown in Table 3; these compositions had a volume electrical resistivity of 0.24 ohm.cm and 0.15 ohm.cm, respectively.

[0088] The melt flow rates (MFR) of Ex3.2 and Ex3.3 could not be measured due to the complete blockage of the die of the tester when attempting to flow the melt out of the tester. It is speculated that the polymers crystallize rapidly above their Tg and therefore solidify before being able to exit the die, thus blocking the orifice of the MFR tester. This situation may be exacerbated by the fact that the presence of high loadings of carbon fillers in these materials may lead to a higher crystallization speed, thereby helping the polymers to solidify faster on cooling.

[0089] The above is intended to be illustrative, not limiting. For example, the above embodiments (or one or more aspects thereof) may be used in combination with each other. Other embodiments may be readily used, for example, by one of ordinary skill in the art upon reviewing the above. The Abstract is provided in accordance with U.S. Patent Law § 1.72(b) to enable the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. Nonetheless, it should be construed that no unclaimed disclosed feature is intended to be essential to any claim. Rather, the subject matter of the invention may lie in less than all features of a particular disclosed embodiment. Thus, it is contemplated that the appended claims are incorporated into the Detailed Description as an example or embodiment, with each claim standing on its own as a separate embodiment, and that such embodiments can be combined with each other in various combinations or permutations. The scope of the disclosure should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. 1. A thermoplastic composition comprising: about 35 wt % to about 65 wt % of at least one polyphenylene sulfide (PPS) polymer; a combination of at least two carbon-based fillers comprising a first carbon-based filler comprising graphite and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof; the first carbon-based filler comprises graphite in an amount of about 30 wt % to about 59 wt %; the composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991; A thermoplastic composition, wherein the combined weight percentage of all components does not exceed 100 wt%, all weight percentages being based on the total weight of said composition.

2. The thermoplastic composition of claim 1 , wherein the second carbon-based filler comprises carbon powder in an amount of about 2 wt % to about 8 wt %.

3. The thermoplastic composition of claim 1 or 2, wherein the second carbon-based filler comprises carbon nanotubes in an amount of about 2 wt % to about 6 wt %.

4. 4. The thermoplastic composition of any one of claims 1 to 3, wherein the composition exhibits a volume electrical resistivity of less than 1 ohm.cm as measured by ASTM D991.

5. 5. The thermoplastic composition of any one of claims 1 to 4, wherein the composition has a through-plane thermal conductivity of at least 0.6 W / mK, determined according to ISO 22007-2, or wherein the composition has an in-plane thermal conductivity of at least 5.4 W / mK, determined according to ISO 22007-2.

6. The thermoplastic composition of any one of claims 1 to 5, wherein the composition has a bulk thermal conductivity of at least 1.8 W / mK.

7. 7. The thermoplastic composition of any one of claims 1 to 6, wherein the composition has a far-field electromagnetic shielding effectiveness (SE) of at least 80 decibels (dB) at frequencies between 3 GHz and 6 GHz, tested in accordance with ASTM D4935.

8. The thermoplastic composition according to any one of claims 1 to 7, wherein the composition comprises at least one further additive.

9. 9. The thermoplastic composition of claim 8, wherein the at least one further additive comprises an acid scavenger, an anti-drip agent, an antioxidant, an antistatic agent, a chain extender, a colorant, a mold release agent, a flow promoter, a lubricant, a plasticizer, a reaction stopper, a flame retardant, a UV reflective additive, an impact modifier, a blowing agent, a reinforcing agent, or a combination thereof.

10. The thermoplastic composition of any one of claims 1 to 9, wherein the composition comprises graphite, carbon powder, and carbon nanotubes.

11. An extruded sheet comprising the composition of any one of claims 1 to 10.

12. 12. The extruded sheet of claim 11, wherein the sheet has a thickness of 0.125 inches (in) or less.

13. 1. A method for forming a composition comprising about 35 wt % to about 65 wt % of at least one polyphenylene sulfide (PPS) polymer and a combination of at least two carbon-based fillers, comprising: combining said at least one PPS polymer and said at least two carbon-based fillers to form a mixture; and extruding the mixture to form the composition. the at least two carbon-based fillers comprise a first carbon-based filler comprising graphite and a second carbon-based filler comprising carbon powder, carbon nanotubes, or a combination thereof; the graphite is present in an amount of about 30 wt % to about 59 wt %; the composition exhibits a volume electrical resistivity of less than about 5 ohm.cm as measured by ASTM D991; A method wherein the combined weight percentage of all components does not exceed 100 wt %, all weight percentages being based on the total weight of the composition.

14. The method of claim 13, wherein the one or more carbon-based fillers are provided in the form of a PPS-based masterbatch composition.

15. 11. An article comprising the thermoplastic composition of any one of claims 1-10, said article comprising: an electrically conductive electrode plate in a flow battery; a thermally conductive plate in a heat exchanger used to transfer heat between two fluids; or an enclosure or package that protects electronic devices from electromagnetic radiation used in medical, military, or aerospace electronics.

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