Composition comprising a thermoplastic elastomer, a VOC containing oil, and a mesopore-containing activated carbon

Abstract

A thermoplastic elastomer composition includes a thermoplastic elastomer, a VOC-containing oil, and an activated carbon having a plurality of pores. The activated carbon has a particle size of 800 µm or less and a pore size in the range of 0.1 nm to 30 µm. The pores of the activated carbon comprise at least 3% of mesopores having diameters of 2 nm to 50 nm and at least 40% of micropores having diameters of less than 2 nm. Thermoplastic elastomer articles may be produced from the thermoplastic elastomer composition, including, for example, automotive interior articles selected from center console trays, door mats, mat pockets, trunk and frunk liners, and instrument panel and dashboard over-molding.

Description

COMPOSITION COMPRISING A THERMOPLASTIC ELASTOMER, A VOC CONTAINING OIL, AND A MESOPORE-CONTAINING ACTIVATED CARBONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and all benefit of U.S. Provisional Patent Application No. 63 / 666,103, filed on June 28, 2024, the entire disclosure of which is fully incorporated herein by reference.FIELD

[0002] The present disclosure relates to thermoplastic elastomer compositions, more particularly, to thermoplastic elastomer compositions comprising a VOC-containing oil and activated carbon having mesopores.BACKGROUND

[0003] Thermoplastic elastomers (TPEs) are an important class of polymeric materials that combine the elastomeric properties of thermoset polymers with the processability of thermoplastic polymers, providing a synergistic effect. These properties make TPEs suitable for various applications where thermosets or thermoplastics alone are not adequate.

[0004] Mineral oil is added to TPE formulations as plasticizer to adjust softness and elasticity, which also acts as a lubricant during processing. TPE formulations often comprise mineral oil in substantial amounts, such as 15-80 wt.% of the total weight of the formulation, resulting in a large carbon footprint originating from the use of mineral oil obtained by crude oil extraction and refinement. The carbon footprint of TPE manufacturing can be reduced by using an oil from a recycled source. However, recycled oils often contain high amounts of volatile organic compounds (VOC), fats, oils, and grease compounds (FOG), and odorous species over permissible limits. Accordingly, there is a need for effective and industrially viable techniques to reduce the unwanted VOC, FOG, and odor in TPEs containing recycled or other VOC-containing oil.SUMMARY

[0005] The following is a brief summary of subject matter that is described in greater detail herein. This summary is not intended to be limiting as to the scope of the claims.

[0006] According to a first aspect of the present disclosure, a thermoplastic elastomer composition comprises a thermoplastic elastomer, a VOC-containing oil, and an activatedcarbon having a plurality of pores. The activated carbon has a particle size of 800 pm or less and a pore size in the range of 0.1 nm to 30 pm. The pores of the activated carbon comprise at least 3% of mesopores having diameters of 2-50 nm and at least 40% of micropores having diameters of less than 2 nm.

[0007] According to other aspects of the present disclosure, a thermoplastic elastomer pellet comprises a thermoplastic elastomer composition. A method for producing the thermoplastic elastomer pellet comprises mixing and extruding a thermoplastic elastomer masterbatch comprising the thermoplastic elastomer composition, and cutting the extruded masterbatch into pellets. A thermoplastic elastomer article comprises a thermoplastic elastomer composition and is produced from the thermoplastic elastomer pellet. The thermoplastic elastomer article may be an automotive interior article selected from center console trays, door mats, mat pockets, trunk and frunk liners, and instrument panel and dashboard over-molding.

[0008] The above summary is not an extensive overview of the compositions, methods, and / or articles discussed herein. It is not intended to identify key / critical elements or to delineate the scope of such compositions, methods, and / or articles. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented in the following paragraphs.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The general concepts, as well as illustrative implementations and advantages thereof, are described below in greater detail, by way of example, with reference to the drawings in which:

[0010] FIG. l is a plot of pore size distribution of the activated carbon in the exemplary compositions.

[0011] FIG. 2 is a plot of pore size distribution of the matrix activated charcoal in the exemplary compositions.DETAILED DESCRIPTION

[0012] Disclosed herein are thermoplastic elastomer compositions comprising a thermoplastic elastomer, a VOC containing oil, and an activated carbon. Also disclosed herein are thermoplastic elastomer pellet and articles produced from the thermoplastic elastomer compositions.

[0013] The terminology as set forth herein is for description of the various aspects only and should not be construed as limiting the disclosure as a whole. All references to singular characteristics or limitations of the present disclosure shall include the corresponding plural characteristic or limitation, and vice versa, unless otherwise specified or clearly implied to the contrary by the context in which the reference is made. Unless specified otherwise, “a,” “an,” “the,” and “at least one” are used interchangeably. Furthermore, as used in the description and the appended claims, the singular forms “a,” “an,” and “the” are inclusive of their plural forms, unless the context clearly indicates otherwise.

[0014] Unless otherwise expressly defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art.

[0015] As used herein, the term “compounding” (including related terms, such as “compounded”) refers to the formation of a composition or mixture via melt mixing a neat polymer resin and at least one other ingredient including, but not limited to, one or more additives, or one or more other polymer resins, or both.

[0016] As used herein, the term “thermoplastic” refers to a polymer that softens when exposed to heat and returns to its original condition when at room temperature.

[0017] Unless otherwise expressly stated, it not intended that any method disclosed herein be construed as requiring that its steps be performed in a specific order, nor that any article set forth herein be construed as requiring specific orders or orientations to its individual components.

[0018] To the extent that the term “includes” or “including” is used in the description or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use.

[0019] Any composition described in the present disclosure can comprise, consist of, or consist essentially of the essential elements of the disclosure as described herein, as well as any additional or optional element described herein, or which is otherwise useful in plastic applications.

[0020] All percentages, parts, and ratios as used herein are by weight of the total blend on an “dry” basis, i.e., without solvents, unless otherwise specified.

[0021] All ranges and parameters, including but not limited to percentages, parts, and ratios, disclosed herein are understood to encompass any and all sub-ranges assumed and subsumed therein, and every number between the endpoints. For example, a stated range of “ 1 to 10” should be considered to include any and all sub-ranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 1 to 6.1, or 2.3 to 9.4), and to each integer (1, 2, 3, 4, 5, 6, 7, 8, 9, and 10) contained within the range. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0022] The term “wt.%” or “weight percent,” as described herein, refers to the weight fraction of the individual component based on a total weight of the thermoplastic elastomer composition, unless otherwise noted.

[0023] Additionally, as used herein, the term “exemplary” is intended to mean serving as an illustration or example of something, and is not intended to indicate a preference.

[0024] The present disclosure is directed to a thermoplastic elastomer composition that comprises a thermoplastic elastomer, a VOC-containing oil, and an activated carbon. The thermoplastic elastomer composition, as well as thermoplastic elastomer articles produced from the thermoplastic elastomer composition, may have reduced VOC emission due to the activated carbon, which will be described below in greater detail.Thermoplastic Elastomer

[0025] The thermoplastic elastomer of the thermoplastic elastomer composition may comprise styrenic block copolymers, thermoplastic vulcanizates, thermoplastic polyurethanes, thermoplastic copolyester, thermoplastic polyamides, or any combinations thereof. In any of the aspects provided herein, the thermoplastic elastomer may be a recycled, reused, or otherwise reclaimed material.

[0026] Particular aspects are directed to thermoplastic elastomers that comprise, consist of, or consist essentially of styrenic block copolymers. The thermoplastic elastomer may comprise a single type of styrenic block or combinations of two or more different types of styrenic block copolymers. Styrenic block copolymers are well known thermoplasticelastomers that utilize styrenic end blocks and butadiene-based mid-blocks. Any available styrenic block copolymers are suitable for use in the present invention. Suitable styrenic block copolymers can be selected also to provide other properties desirable for the end-use application.

[0027] Non-limiting examples of suitable styrenic block copolymers include styrene- ethylene / butylene-styrene (SEBS), sty rene-ethylene / propylene- styrene (SEPS), styrene- ethylene / ethylene / propylene-styrene (SEEPS), styrene-isobutylene-styrene (SIBS), styrenebutadiene- styrene (SBS), styrene-isoprene-styrene (SIS), and combinations thereof.

[0028] In various aspects, the thermoplastic elastomer may comprise, consist of, or consist essentially of a SEBS polymer that includes blocks of styrene-ethylene and butylenestyrene polymers. The SEBS polymer can be a diblock or triblock copolymer based on styreneethylene and butylene- styrene.

[0029] The styrenic block copolymer may be hydrogenated, such as partially hydrogenated or fully hydrogenated. Alternatively, the styrenic block copolymer may be nonhydrogenated.

[0030] According to some aspects, the styrenic block copolymer may be selected from hydrogenated styrene-isoprene-styrene block copolymer with hydrogenated vinylic isoprene midblock or high vinyl styrene-(ethylene / butylene)-styrene block copolymer or combinations of these and / or other styrenic block copolymers.

[0031] The molecular weight of the thermoplastic elastomer is not particularly limited. For example, the number average molecular weight (Mn) of the thermoplastic elastomer may be within the range of l x 104to I x lO6, 5x l04to 5x l05, and I x lO5to 2x l05, including all subranges and endpoints therebetween.

[0032] In any of the aspects provided herein, the thermoplastic elastomer may be present in the thermoplastic elastomer composition in an amount of 35 wt.% to 95 wt.% based upon the total weight of the composition. For example, the thermoplastic elastomer may be present in the thermoplastic elastomer composition in an amount of 40 wt.% to 93 wt.%, 45 wt.% to 90 wt.%, 50 wt.% to 87 wt.%, 55 wt.% to 85 wt.%, 60 wt.% to 83 wt.%, or 65 wt.% to 80 wt.%, including all subranges and endpoints therebetween.VOC-Containing Oil

[0033] The VOC-containing oil of the thermoplastic elastomer composition comprises an oil including volatile organic compounds (VOC). VOCs are compounds that have a high vapor pressure and emitted as gasses from certain solids or liquids. VOCs include a variety ofchemicals that are often regulated as pollutants. The oil may be a virgin oil or it may be a recycled or otherwise reclaimed or reused oil. The oil may comprise, for example, mineral oils, base oils, technology oils, process oils, medical grade oils, and the like, or any combinations thereof. The VOC may be present in the oil as an impurity that has not been removed during refining or recycling the oil.

[0034] The emission of volatile organic compounds by the oil can be evaluated by the VDA 278 standard for automotive materials. Under the VDA 278 standard, the VOC value characterizes the emission of readily volatile to medium volatile compounds up to C25, and the FOG value characterizes the emission of semi-volatile compounds with volatilities from C14 to C32. The VOC-containing oil may have a VOC value of 20 ppm or more, as measured in accordance with the VDA 278 standard, including, for example, 30 ppm or more, 40 ppm or more, 50 ppm or more, 60 ppm or more, 70 ppm or more, 80 ppm or more, 90 ppm or more, 100 ppm or more, 500 ppm or more, 1,000 ppm or more, and 2,000 ppm or more. The VOC- containing oil may have a VOC value of 10,000 ppm or less under the VDA 278 standard, including, for example, 5,000 ppm or less, 3,000 ppm or less, 2500 ppm or less, 2,000 ppm or less, 1,500 ppm or less, 1,000 ppm or less, and 500 ppm or less.

[0035] With regard to FOG, the VOC-containing oil may have a FOG value of 50 ppm or more under the VDA 278 standard, including, for example, 100 ppm or more, 500 ppm or more, 1,000 ppm or more, 2,000 ppm or more, 3,000 ppm or more, and 4,000 ppm or more. The VOC-containing oil may have a FOG value of 5,000 ppm or less under the VDA 278 standard, including, for example, 4,000 ppm or less, 3,000 ppm or less, 2,000 ppm or less, 1,000 ppm or less, and 500 ppm or less.

[0036] The viscosity of the VOC-containing oil can be measured by a rotational rheometer (e.g., TA Instruments ARES-G2 Rheometer). In any of the aspects provided herein, the VOC-containing oil may have a complex viscosity of 0.02 Pa.s to 0.3 Pa.s at 25 °C, including, for example, 0.05 Pa.s to 2.5 Pa.s, 0.08 Pa.s to 0.2 Pa.s, and 0.1 Pa.s to 0.15 Pa.s, including all subranges and endpoints therebetween. The VOC-containing oil may have a kinematic viscosity of 5 centistokes (cSt) to 60 cSt at 40 °C, including, for example, 10 cSt to 55 cSt, 15 cSt to 50 cSt, 20 cSt to 45 cSt, and 25 cSt to 40 cSt, including all subranges and endpoints therebetween.

[0037] The VOC-containing oil may act as a plasticizer that affects the softness and elasticity of articles formed from the thermoplastic elastomer composition, and may also act as a lubricant during processes such as blending, extrusion, and molding. Therefore, the amount of the VOC-containing oil in the thermoplastic elastomer composition can be selected basedon the desired mechanical properties of the thermoplastic elastomer article and the thermoplastic elastomer composition during processing. In any of the aspects provided herein, the VOC-containing oil may be present in the thermoplastic elastomer composition in an amount of 5 wt.% to 80 wt.% based upon the total weight of the composition, including, for example, 5 wt.% to 65 wt.%, 10 wt.% to 50 wt.%, 15 wt.% to 40 wt.%, 20 wt.% to 35 wt.%, and 25 wt.% to 30 wt.%, including all subranges and endpoints therebetween.Activated Carbon

[0038] The thermoplastic elastomer composition further includes an adsorbent material. The adsorbent material may comprise, consist of, or consist essentially of, activated carbon. The activated carbon of the thermoplastic elastomer composition may be derived from coconut shell, nut shells, sugarcane bagasse, coconut husks, cotton, crop remnants, grain remnants, grass residues, coffee grounds, wood, coal, lignite, petroleum pitch, lignocellulose, carbohydrates, petroleum, nut pits, natural polymers, and the like or any combinations thereof.

[0039] The pore size and pore size distribution of the activated carbon can be determined using a Brunauer-Emmett-Teller (BET) porosity and surface area analyzer based on the adsorption-desorption isotherms of nitrogen and carbon dioxide. Specific pore volume can be determined using the Barrett- Joy ner-Halenda (BJH) method based on data of the relative pressure vs. amount of gas adsorbed. Under non-local density functional theory (NLDFT) models, adsorption isotherms of nitrogen and carbon dioxide can be obtained and combined to determine the specific volume of pores having a certain size. The distribution of pore size can be determined based on the volume of gas adsorbed by pores with a certain size in relation to the total adsorption by the activated carbon.

[0040] The activated carbon may comprise a plurality of pores having pore sizes ranging from 0.1 nm to 30 pm, including, for example, 0.2 nm to 10 pm, 0.3 nm to 1 pm, 0.4 nm to 500 nm, 0.5 nm to 100 nm, including all subranges and endpoints therebetween.

[0041] Pores of the activated carbon having diameters of less than 2 nm are categorized as micropores. In any of the aspects provided herein, the pores of the activated carbon may comprise at least 40% of micropores, including, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, and at least 90%, based on the volume of gas adsorbed. For example, the pores of the activated carbon may comprise 40% to 97% of micropores, including 60% to 95%, 70% to 93%, 80% to 91%, and 85% to 90%, including all subranges and endpoints therebetween.

[0042] Pores of the activated carbon having diameters of 2 nm to 50 nm are categorized as mesopores. In any of the aspects provided herein, the pores of the activated carbon may comprise at least 3% of mesopores, including, for example, at least 5%, at least 8%, at least 10%, at least 12%, and at least 15%, based on the volume of gas adsorbed. For example, the pores of the activated carbon may comprise 3% to 20% of mesopores, including 5% to 16%, 8% to 14%, and 10% to 12%, including all subranges and endpoints therebetween.

[0043] Pores of the activated carbon having diameters of larger than 50 nm are categorized as macropores. In any of the aspects provided herein, the pores of the activated carbon may comprise no macropores or at least 0.1% of macropores, including, for example, at least 0.5%, at least 0.8%, at least 1%, at least 1.5%, and at least 2%, based on the volume of gas adsorbed. For example, the pores of the activated carbon may comprise 0% to 20% of macropores, including 0.1% to 15%, 0.5% to 10%, 0.8% to 5%, and 1% to 3%, including all subranges and endpoints therebetween.

[0044] The activated carbon conventionally used as additive in thermoplastic elastomer compositions includes high surface area coconut shell carbon having predominantly (i.e., greater than 97%, 98%, 99%, or even 99.9%) micropores. In contrast, it has been surprisingly discovered that VOC and odor emission from articles formed from the thermoplastic elastomer composition can be reduced when the activated carbon comprises at least 3% of mesopores. The VOC and odor reduction by the presence of mesopores will be described in more detail below with reference to exemplary compositions.

[0045] The activated carbon may be in powder or granular powder form. The particle size of the activated carbon can be expressed in mesh size, i.e., the size of the mesh sieves the activated carbon is able to pass through. In any of the aspects provided herein, the activated carbon may have particle sizes no larger than 100 pm, including, for example, no larger than 150 pm, no larger than 200 pm, no larger than 250 pm, no larger than 500 pm, and no larger than 800 pm. For example, the activated carbon may have particle sizes between 400 mesh (about 40 pm) and 6 mesh (about 3,400 pm), including between 200 mesh (about 75 pm) and 10 mesh (about 2,000 pm), between 100 mesh (about 150 pm) and 14 mesh (about 1,400 pm), between 60 mesh (about 250 pm) and 18 mesh (about 1 pm), and between 40 mesh (about 400 pm) and 20 mesh (about 800 pm), including all subranges and endpoints therebetween. The activated carbon may be 20 x 40 mesh with particle sizes between 40 mesh (about 400 pm) and 20 mesh (about 800 pm), or 20 x 60 mesh with particle sizes between 60 mesh (about 250 pm) and 20 mesh (about 800 pm).

[0046] The specific surface area of the activated carbon can be determined by Brunauer-Emmett-Teller (BET) surface area analysis through the adsorption and release of an adsorbate gas. In any of the aspects provided herein, the activated carbon may have a BET surface area of 200 m2 / g to 1500 m2 / g, including, for example, 250 m2 / g to 1000 m2 / g, 280 m2 / g to 800 m2 / g, and 300 m2 / g to 700 m2 / g, including all subranges and endpoints therebetween, based on BET surface area analysis with nitrogen as adsorbate.

[0047] In any of the aspects provided herein, the activated carbon may be present in the thermoplastic elastomer composition in an amount of 0.04 wt.% to 5 wt.% based upon the total weight of the composition, including, for example, 0.07 wt.% to 4 wt.%, 0.1 wt.% to 3 wt.%, 0.2 wt.% to 2.5 wt.%, 0.5 wt.% to 2 wt.%, and 0.8 wt.% to 1.5 wt.%, including all subranges and endpoints therebetween.Other Components

[0048] The thermoplastic elastomer composition may further include one or more additives. Suitable additives include commercially available plastics additives, including additives available in the reference E. W. Flick, “Plastics Additives Database,” Plastics Design Library (Elsevier 2004). The additives may include antimicrobial agents, antioxidants, UV stabilizers, pigments, colorants, fire retardants, impact modifiers, lubricants, molecular sieves (e.g., with sizes from 3A to 13X), or combinations thereof. The one or more additives may be included in the thermoplastic elastomer composition in any amount sufficient to obtain a desired processing or performance property for the thermoplastic elastomer composition and / or the thermoplastic article. In certain aspects, the additives may be present in the thermoplastic elastomer composition in an amount of 5 wt.% or less, collectively or individually.VOC Emission

[0049] In any of the aspects provided herein, the thermoplastic elastomer composition may have a VOC value of 500 ppm or less under the VDA 278 standard, including, for example, 400 ppm or less, 300 ppm or less, 200 ppm or less, and 100 ppm or less. For example, the thermoplastic elastomer composition may have a VOC value of 50 ppm to 500 ppm, including 60 ppm to 300 ppm, 70 ppm to 200 ppm, 80 ppm to 150 ppm, and 90 ppm to 100 ppm, including all subranges and endpoints therebetween. In any of the aspects provided herein, the thermoplastic elastomer composition may have a FOG value of 1,500 ppm or less under the VDA 278 standard, including, for example, 1,400 ppm or less, 1,300 ppm or less, 1,200 ppm or less, 1,100 ppm or less, 1,000 ppm or less, and 900 ppm or less. For example, thethermoplastic elastomer composition may have a FOG value of 500 to 1,500 ppm, including 700 to 1,400 ppm, 800 to 1,300 ppm, 900 to 1,200 ppm, and 1,000 to 1,100 ppm, including all subranges and endpoints therebetween.

[0050] The activated carbon, as an adsorbent material, adsorbs the VOC in the VOC- containing oil to reduce the emission from the thermoplastic elastomer composition. In any of the aspects provided herein, the thermoplastic elastomer composition may have 20 % or more reduction in VOC value under the VDA 278 standard, as compared to an otherwise identical composition not including the activated carbon, including, for example, 40 % or more, 60 % or more, 80 % or more, 90 % or more, and 95 % or more reduction in VOC value. In any of the aspects provided herein, the thermoplastic elastomer composition may have 20 % or more reduction in FOG value under the VDA 278 standard, as compared to an otherwise identical composition not including the activated carbon, including, for example, 40 % or more, 60 % or more, 80 % or more, 90 % or more, and 95 % or more reduction in FOG value.

[0051] The emission of odor from the thermoplastic elastomer composition can be evaluated by the VDA 270 method for automotive materials. Under the VDA 270 method, the presence of odor is evaluated by a panel of examiners on a scale from 1 (imperceptible) to 6 (intolerable) and the average value (or median) is taken. In any of the aspects provided herein, the thermoplastic elastomer composition may have an odor rating of 3 or lower under the VDA 270 method, including, for example, 2.7 or lower, 2.5 or lower, 2.3 or lower, 2 or lower, 1.8 or lower, and 1.5 or lower. For example, the thermoplastic elastomer composition may have an odor rating between 1 and 3, including between 1 and 2.7, between 1.5 and 2.5, and between 1.7 and 2.3, including all subranges and endpoints therebetween.Thermoplastic Elastomer Pellet and Article

[0052] In an aspect provided herein, a thermoplastic elastomer pellet is disclosed, which comprises the thermoplastic elastomer composition described above. A method for producing the thermoplastic elastomer pellet may comprise mixing and extruding a thermoplastic elastomer masterbatch comprising the thermoplastic elastomer composition, and cutting the extruded masterbatch into pellets. The method may be performed with a conventional double screw extruder and a pelletizer.

[0053] In an aspect provided herein, a thermoplastic elastomer article is disclosed. The thermoplastic elastomer article comprises the thermoplastic elastomer composition described above and may be produced from the thermoplastic elastomer pellet by, for example, injection molding, blow molding, compression molding, extrusion, or any other suitable processes forforming plastic articles. In aspects provided herein, the thermoplastic elastomer article may be an automotive interior article selected from center console trays, door mats, mat pockets, trunk and frunk liners, and instrument panel and dashboard over-molding. The thermoplastic elastomer article may have acceptable levels of VOC, FOG, and odor emission as measured in accordance with industry standards such as VDA 278 and VDA 270.

[0054] In any of the aspects provided herein, the thermoplastic elastomer article may have a VOC value of 200 ppm or less under the VDA 278 standard, including, for example, 150 ppm or less, 125 ppm or less, 100 ppm or less, 75 ppm or less, and 50 ppm or less. For example, the thermoplastic elastomer article may have a VOC value of 30 ppm to 200 ppm under the VDA 278 standard, including 35 ppm to 175 ppm, 40 ppm to 150 ppm, 45 ppm to 125 ppm, and 50 ppm to 100 ppm, including all subranges and endpoints therebetween. In any of the aspects provided herein, the thermoplastic elastomer article may have a FOG value of 1,450 ppm or less under the VDA 278 standard, including, for example, 1,200 ppm or less, 1,000 ppm or less, 750 ppm or less, 500 ppm or less, and 300 ppm or less. For example, the thermoplastic elastomer article may have a FOG value of 200 ppm to 1,450 ppm under the VDA 278 standard, including 400 ppm to 1,300 ppm, 500 ppm to 1,200 ppm, 600 ppm to 1,100 ppm, and 700 ppm to 1,000 ppm, including all subranges and endpoints therebetween.

[0055] In any of the aspects provided herein, the thermoplastic elastomer article may have an odor rating of 3 or lower under the VDA 270 wet test method, including, for example, 2.7 or lower, 2.5 or lower, 2.3 or lower, 2 or lower, 1.8 or lower, 1.5 or lower, 1.4 or lower, and 1.3 or lower. In any of the aspects provided herein, the thermoplastic elastomer article may have an odor rating of 3 or lower, 2 or lower, or 1 under the VDA 270 wet test method. For example, the thermoplastic elastomer article may have an odor rating between 1 and 3, including between 1 and 2.7, between 1.5 and 2.5, and between 1.7 and 2.3, including all subranges and endpoints therebetween.

[0056] In any of the aspects provided herein, the thermoplastic elastomer article may have an odor rating of 3 or lower under the VDA 270 dry test method, including, for example, 2.7 or lower, 2.5 or lower, 2.3 or lower, 2 or lower, 1.8 or lower, and 1.5 or lower In any of the aspects provided herein, the thermoplastic elastomer article may have an odor rating of 3 or lower, 2 or lower, or 1 under the VDA 270 dry test method. For example, the thermoplastic elastomer article may have an odor rating between 1 and 3, including between 1 and 2.7, between 1.5 and 2.5, and between 1.7 and 2.3, including all subranges and endpoints therebetween.Examples

[0057] The materials used in the exemplary compositions are set forth in Table 1 below.TABLE 1

[0058] The pore size distributions of the activated carbon and the matrix activated charcoal are provided in FIG. 1 and FIG. 2, respectively. In FIG. 1 and FIG. 2, it can be seen that the activated carbon includes a substantial portion of pores up to 50 nm diameter, while the matrix activated charcoal includes almost no pores larger than 5 nm diameter. The differences in microstructure, such as average pore size and pore size distribution, are shown in Table 2 below.TABLE 2

[0059] To evaluate the reduction of VOC emission by activated carbon in thermoplastic elastomer (TPE) compositions, samples of TPE compositions were prepared with the compositions set forth in Table 3 below. The VOC and FOG values of each sample were measured under the VDA 278 standard.TABLE 3

[0060] From comparison of Samples 1-1 and 1-2, it is shown that Sample 1-2, which includes recycled oil, has significantly higher VOC emissions than Sample 1-1, which includes oil that has not been recycled. Activated carbon was found to reduce emissions in recycled oil where Sample 1-3 (recycled oil with 1.5 wt.% activated carbon additive) had lower emissions than Sample 1-2 (recycled oil).

[0061] To evaluate the odor reduction by activated carbon in thermoplastic elastomer articles, TPE compositions were prepared that included the styrenic block copolymer of Table 1, with the additional components as set forth in Table 4 below. The compositions were extruded with Leistritz 18 mm x 40D twin screw extruder at 180 °C at a screw rpm of 600 and throughput of 11 Ibs / hr to produce TPE samples.TABLE 4

[0062] The emission of odor from the samples was evaluated by the VDA 270 method for automotive materials, including dry and wet test protocols, with results shown in Tables 5-1 and 5-2 below. The container used in the test was scaled down from 1 -liter size to U pint size to accommodate the size of the samples. According to the VDA 270 method scale, a value of 1 indicates that an odor is imperceptible and a value of 6 indicates an intolerable odor. A sample should have a rating3 under both the dry and wet test protocols to pass the test and a rating less than 3 is preferred.TABLE 5-1TABLE 5-2

[0063] Under the wet test protocol, all samples had odor ratings of less than 3 under the VDA 270 method. Under the dry test protocol, Samples Z, G, and Q prepared with different amounts of activated carbon achieved an odor rating of 2, as opposed to the control Sample R (recycled oil with no activated carbon) with an odor rating of 3. As such, treating the recycled oil with activated carbon can effectively reduce the odor emission of the thermoplastic elastomer articles.

[0064] Furthermore, to evaluate the effect of pore size on odor reduction, samples of recycled oil added with various adsorbents as set forth in Table 6 below were prepared. Foreach of Samples 2-1 to 2-4, two samples were prepared with different amounts of adsorbent. Each of the samples was evaluated whether there was a reduction in odor emission as compared to the Comparative Sample without any adsorbent.TABLE 6

[0065] In general, adsorbents with smaller pore sizes demonstrate better adsorption capacity and VOC reduction capability. This is consistent with the test results for Samples 2- 3 and 2-4, where molecular sieve 13X was effective in reducing odor of the thermoplastic elastomer article but molecular sieve 3 A was not effective when added in the same amounts of 10-20 wt.%. However, even for molecular sieve 13X, a large amount of addition was required in order to observe odor reduction. At lower amounts such as 5 wt.% or less, odor reduction could not be observed under the VDA 270 method (see Sample 2-5).

[0066] Surprisingly, the activated carbon was effective in reducing odor emission (Sample 2-1) when added in an amount of 0.05-1 wt.%, while the matrix activated charcoal was not effective (Sample 2-2) when added in the same amount, although the matrix activated charcoal had smaller average pore size, larger BET surface area, and larger micropore volume (see Table 2). As such, the better odor reduction by the activated carbon can be attributed to its pore size distribution which includes more pores of larger sizes. In accordance with the present disclosure, it was found that the presence of at least 3% of mesopores in the activated carbon resulted in the unexpected improvement in odor reduction. It was also found that at least 40% of micropores in the activated carbon is required for satisfactory adsorption capacity. As result, thermoplastic elastomer articles with less VOC, FOG, and odor emission can beproduced with a relatively small addition of activated carbon, e.g., 5 wt.% or less, where the pores of the activated carbon comprise at least 3% of mesopores and at least 40% of micropores.

[0067] It will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

Claims

CLAIMS1. A composition comprising: a thermoplastic elastomer; a VOC-containing oil; and an activated carbon having a plurality of pores, wherein the activated carbon has a particle size of 800 pm or less and a pore size in the range of 0.1 nm to 30 pm, and wherein the pores of the activated carbon comprise at least 3% of mesopores having diameters of 2 nm to 50 nm and at least 40% of micropores having diameters of less than 2 nm.

2. The composition of claim 1, wherein the thermoplastic elastomer includes one or more from the group including styrenic block copolymers, thermoplastic vulcanizates, thermoplastic polyurethanes, thermoplastic copolyesters, thermoplastic polyamides, and any combinations thereof.

3. The composition of claim 1 or claim 2, wherein the thermoplastic elastomer is present in the composition in an amount of 35 wt.% to 95 wt.%, based upon the total weight of the composition.

4. The composition of any one of claims 1 to 3, wherein the VOC-containing oil includes one or more from the group including base oils, technology oils, process oils, and medical grade oils.

5. The composition of any one of claims 1 to 4, wherein the VOC-containing oil has a kinematic viscosity of 5 cSt to 60 cSt at 40 °C.

6. The composition of any one of claims 1 to 5, wherein the VOC-containing oil has a VOC value between 80 ppm and 3000 ppm, as measured in accordance with VDA 278.

7. The composition of any one of claims 1 to 6, wherein the VOC-containing oil is present in the composition in an amount of 5 wt.% to 65 wt.%, based upon the total weight of the composition.

8. The composition of any one of claims 1 to 7, wherein the activated carbon is derived from coconut shell, nut shells, sugarcane bagasse, coconut husks, cotton, crop remnants, grain remnants, grass residues, coffee grounds, wood, coal, lignite, petroleum pitch, or combinations thereof.

9. The composition of any one of claims 1 to 8, wherein 0-20% of the pores of the activated carbon comprise macropores larger than 50 nm in diameter.

10. The composition of any one of claims 1 to 9, wherein the activated carbon has a BET surface area in the range of 200 m2 / g to 1500 m2 / g.

11. The composition of any one of claims 1 to 10, wherein the activated carbon is present in the composition in an amount of 0.04 wt.% to 5 wt.%, based upon the total weight of the composition.

12. The composition of any one of claims 1 to 11, wherein the composition includes one or more additives selected from the group including antioxidants, UV stabilizers, pigments, dyes, fillers, colorants, impact modifiers, lubricants, molecular sieves, and fire retardants.

13. The composition of any one of claims 1 to 12, wherein at least one of the thermoplastic elastomer or the VOC-containing oil is recycled.

14. The composition of any one of claims 1 to 13, wherein the composition has a VOC value between 50 ppm and 500 ppm, as measured in accordance with VDA 278.

15. The composition of any one of claims 1 to 14, wherein the composition has a 20 % reduction in VOC value compared to an otherwise identical composition not including the activated carbon.

16. The composition of any one of claims 1 to 15, wherein the composition has a 20 % reduction in VOC value compared to the VOC-containing oil.

17. The composition of any one of claims 1 to 16, wherein the composition has a FOG value in the range of 500 ppm to 1500 ppm, as measured in accordance with VDA 278.

18. The composition of any one of claims 1 to 17, wherein the composition has an odor rating between 1 and 3, as measured in accordance with VDA 270.

19. A thermoplastic elastomer article comprising the composition of any one of claims 1 to 18.

20. The thermoplastic elastomer article of claim 19, wherein the odor rating of the thermoplastic elastomer article is less than 3, as measured in accordance with VDA 270.

21. The thermoplastic elastomer article of claim 19 or claim 20, wherein the VOC value of the thermoplastic elastomer article is 30 ppm to 200 ppm, as measured in accordance with VDA 278.

22. The thermoplastic elastomer article of any one of claims 19 to 21, wherein the FOG value of the thermoplastic elastomer article is 200 ppm to 1450 ppm, as measured in accordance with VDA 278.

23. The thermoplastic elastomer article of claim 19, wherein the thermoplastic elastomer article is an automotive interior article selected from center console trays, door mats, mat pockets, trunk and frunk liners, and instrument panel and dashboard over-molding.

24. A thermoplastic elastomer pellet comprising: a thermoplastic elastomer, a VOC containing oil; and an activated carbon, wherein the activated carbon has a particle size of 800 pm or less, wherein the activated carbon has a pore size in the range of 0.1 nm to 30 pm, and wherein pores of the activated carbon comprise at least 3% of mesopores having diameters of 2 nm to 50 nm and at least 40% of micropores having diameters of less than 2 nm.

25. A method for producing a thermoplastic elastomer pellet, comprising: mixing and extruding a thermoplastic elastomer masterbatch; andcutting the extruded thermoplastic elastomer masterbatch into pellets with a pelletizer, wherein the thermoplastic elastomer masterbatch comprises: a thermoplastic elastomer; a VOC containing oil; and an activated carbon, wherein the activated carbon has a particle size of 800 pm or less, wherein the activated carbon has a pore size in the range of 0.1 nm to 30 pm, and wherein pores of the activated carbon comprises at least 3% of mesopores having diameters of 2 nm to 50 nm and at least 40% of micropores having diameters of less than 2 nm.

Images