Expanded propylene-based elastomer compositions, methods of manufacture and products made therefrom

Abstract

A foamed polymer composition and an article made therefrom are disclosed. More specifically, the foamed polymer composition includes a propylene-based elastomer. The composition including such a propylene-based elastomer requires less energy to mold without compromising the performance of the foamed article.

Description

[Technical Field]

[0001] Inventor:Jie Yu JIN;Yan WANG;Haibin QIU;Yujie SHENG;Liang LI;Haiyin HUA;Hongchao WANG;Yaxian WANG;Tao TANG;Li MINGGANG

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 488,467, filed March 3, 2023, entitled Expanded Propylene-Based Elastomer Compositions, Methods of Manufacturing, and Products Produced Therefrom, the entirety of which is incorporated herein by reference. FIELD OF THE INVENTION Embodiments of the present invention relate generally to foamed polymer compositions and products made therefrom. More particularly, such embodiments relate to foamed polymer compositions made from propylene-based elastomers. [Background technology]

[0003] Expanded beads are physical foam products that are widely used in industrial packaging or automotive applications. EPP (expandable polypropylene) is typically used in the packaging industry to replace cardboard boxes or as rear seat components to reduce the weight of automobiles. EPS (expandable polystyrene) is typically used to protect items in packaging during transportation. EPP typically has better mechanical properties than EPS, and EPP can be recycled and reused, making it more sustainable than EPS. Therefore, EPP is increasingly being used in industries to replace EPS and other packaging formats. Currently, RCP (random copolymer) or terPP is used as the raw material to produce EPP. After the expanded beads are produced, the beads are typically molded using steam. Due to the Vicat or melt temperature of EPP, the steam pressure requirement is typically 2-3 kg / cm to bring the temperature necessary to mold the EPP beads. 2The energy cost of steam can be as much as half of the total cost of the final product. Therefore, there is a need for expanded beads made from alternative polymeric materials that require less energy to form and do not compromise product performance. References included in the Invention Disclosure Statement: CN105885241A, CN105885242A, CN107828134B, U.S. Patent Application Publication No. 2020-0181350. Summary of the Invention

[0004] and a blowing agent, wherein the polymer blend comprises at least 5 wt. % of at least one propylene-based elastomer, based on the total weight of the composition, comprising propylene and about 15 wt. % to about 30 wt. % of units derived from one or more alpha-olefins, based on the total weight of the elastomer, and the propylene-based elastomer has a MFR of at least 3 g / 10 min and a heat of fusion (Hf) of about 3 J / g to about 75 J / g, as determined by DSC; less than 95 wt. % of at least one polypropylene, based on the total weight of the composition; and a blowing agent, wherein prior to combining with the blowing agent, the polymer blend has a melt flow rate of at least 0.80 g / cm. 3 and after the blend is foamed, the foamed article has a density of 0.2 g / cm 3 A foamable polymer composition is disclosed having the following density: The expanded beads comprise at least 80 wt. %, based on the total weight of the expanded beads, of at least one propylene-based elastomer comprising propylene and about 15 wt. % to about 30 wt. % of units derived from one or more alpha-olefins, based on the total weight of the elastomer, the propylene-based elastomer having an MFR of at least 3 g / 10 min and a heat of fusion (Hf) of about 3 J / g to about 75 J / g, as determined by DSC. A method of producing a foamed polymer composition includes mixing a blowing agent with a molten polymer composition to form a foamable mixture, forming the foamable mixture such that the blowing agent expands within the mixture to produce a foam, and 3and obtaining a foamed article having a density of:

[0005] A method for producing an expanded bead article includes introducing a plurality of expanded beads into a mold, increasing the pressure in the mold to a high pressure state of 0.1 to 0.5 MPa, heating the expanded beads in the mold to an elevated temperature state of 35 to 125°C, maintaining the high pressure and elevated temperature state for a compression time to form an expanded bead article, and removing the article. So that the above-described features of the present invention may be understood in detail, a more particular description of the invention briefly summarized above can be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention, which may admit of other equally effective embodiments. It is emphasized that the drawings are not necessarily to scale, and that certain features and certain perspectives of the drawings may be exaggerated in scale or shown diagrammatically for the sake of clarity and / or conciseness. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a bead expansion device. [Figure 2A] 1 is an SEM image of foam sheet No. 1 in Example 1. [Figure 2B] This is a magnified image of the SEM shown in FIG. [Figure 3] 1 is a graph of the DSC curve of sample EFB-003. [Figure 4] 1 is a graph of the DSC curve of sample EFB-006. [Figure 5] 1 is a graph of the DSC curve of sample EFB-013. [Figure 6] Photographs of steam-formed samples of (A) EFB-003 and (B) EFB-006. [Figure 7] 1 is a photograph of a steam-formed sample of EFB-013. [Figure 8] 1 is a graph of the DSC curve of an EFB sample containing PBE3. [Figure 9] This is an SEM image of an EFB containing PBE3. [Figure 10A] 1 is a photograph of a steam-formed sample of PBE EFB. [Figure 10B] 1 is a photograph of a cross section of a steam-formed sample of PBE.EFB. [Figure 11] 1 is a graph of a DSC curve of EFB containing PBE3. [Figure 12] 1 is a graph of a DSC curve of EFB containing PBE2. [Figure 13] FIG. 1 is a simplified diagram of a compression molding process. DETAILED DESCRIPTION OF THE INVENTION

[0007] It should be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the present invention. To simplify the disclosure, exemplary embodiments of components, arrangements, and configurations are described below; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the present invention. In addition, the present disclosure may repeat reference numerals and / or letters in the various embodiments provided herein and throughout the figures. This repetition is for the purposes of simplicity and clarity and does not, in itself, describe a relationship between the various embodiments and / or configurations. Furthermore, references to forming a first feature on or above a second feature in the following description may include embodiments in which the first and second features are formed in direct contact with each other, and may also include embodiments in which an additional feature may be formed between the first and second features such that the first and second features are not in direct contact with each other. Finally, the embodiments presented below may be combined in any combination, i.e., any element from one embodiment may be used in any other embodiment without departing from the scope of the present disclosure. Additionally, certain terms are used throughout the following description and claims to refer to particular components. Those skilled in the art will understand that various entities may refer to the same component by different names, and thus, the naming conventions for elements described herein are not intended to limit the scope of the invention unless otherwise specified herein. Furthermore, the naming conventions used herein are not intended to distinguish between components that differ in name but not function.

[0008] In the following discussion and claims, the terms "including" and "comprising" are used in an inclusive manner and should therefore be interpreted to mean "including, but not limited to." The phrase "consisting essentially of" means that the described / claimed composition does not contain any other component that significantly alters its properties by more than 5%, and in any case does not contain any other component to a level greater than 3% by weight. The term "or" is intended to cover both exclusive and inclusive cases, i.e., "A or B" is intended to be synonymous with "at least one of A and B," unless otherwise specified herein. The indefinite articles "a" and "an" refer to both singular (i.e., "one") and plural referents (i.e., one or more) unless the context clearly dictates otherwise. For example, embodiments using "an olefin" include embodiments in which one, two, or more olefins are used, unless specified to the contrary or unless the context clearly states that only one olefin is used.

[0009] The terms "wt%" mean weight percentage, "vol%" mean volume percentage, "mol%" mean mole percentage, "ppm" mean parts per million, and "ppm wt" and "wppm" are used interchangeably and mean parts per million by weight. All concentrations herein are expressed based on the total amount of the composition in question unless otherwise specified. The term "polymer" refers to any two or more of the same or different repeat units / mer units or units. The term "homopolymer" refers to a polymer having the same units. The term "copolymer" refers to a polymer having two or more units that are different from each other, including terpolymers, etc. The term "terpolymer" refers to a polymer having three units that are different from each other. The term "different," when referring to units, refers to units that differ from each other by at least one atom, or units that are isomerically different. Similarly, the definition of polymer, as used herein, includes homopolymers, copolymers, etc. As an example, if a copolymer is described as having a "propylene" content of 10% to 30% by weight, it is understood that the repeat units / mer units, or simply units, in the copolymer are derived from propylene in the polymerization reaction, and that the propylene-derived units are present in an amount of 10% to 30% by weight based on the mass of the copolymer.

[0010] The term "α-olefin" refers to any linear or branched carbon and hydrogen compound having at least one double bond between an α-carbon atom and a β-carbon atom. For purposes of this specification and the appended claims, when a polymer or copolymer is described as comprising an α-olefin, e.g., a poly-α-olefin, the α-olefin present in such a polymer or copolymer is the polymerized form of the α-olefin. The nomenclature of elements and their groups used herein follows the periodic table used by the International Union of Pure and Applied Chemistry since 1988. An example of a periodic table is shown on the inside cover page of Advanced Inorganic Chemistry, 6th Edition, by F. Albert Cotton et al. (John Wiley & Sons, Inc., 1999). As used herein, the term "monomer" or "comonomer" can refer to a monomer used to form a polymer, e.g., an unreacted chemical compound in its pre-polymerization form, or it can refer to the monomer after it has been incorporated into a polymer, also referred to herein as a "unit derived from [monomer]."

[0011] The term "copolymer" is meant to include polymers having two or more types of monomers, and may contain other monomers, and may refer to interpolymers, terpolymers, etc. The term "polymer," as used herein, includes, but is not limited to, homopolymers, copolymers, terpolymers, etc., as well as alloys and blends thereof. The term "polymer," as used herein, also includes impact copolymers, block copolymers, graft copolymers, random copolymers, and alternating copolymers. The term "polymer," unless otherwise specified, is further intended to include all possible geometric configurations. Such configurations may include isotactic, syndiotactic, and random symmetries. The term "polymer" refers to any two or more of the same or different repeat units / mer units or units. The term "blend," as used herein, refers to a mixture of two or more polymers. The term "homopolymer" refers to a polymer having the same units. The term "copolymer" refers to a polymer having two or more units that are different from each other, including terpolymers, etc. The term "terpolymer" refers to a polymer having three units that are different from each other. The term "different," when referring to units, refers to units that differ from each other by at least one atom, or units that are isomerically different. Similarly, the definition of polymer, as used herein, includes homopolymers, copolymers, etc. As an example, if a copolymer is described as having a "propylene" content of 10% to 30% by weight, it is understood that the repeat units / mer units, or simply units, in the copolymer are derived from propylene in the polymerization reaction, and that the propylene-derived units are present in an amount of 10% to 30% by weight based on the mass of the copolymer.

[0012] The term "elastomer" is intended to mean any polymer that exhibits some degree of elasticity, which is the ability of a material to be deformed by a force (such as by stretching) and to at least partially return to its original dimensions when the force is removed. The term "α-olefin" or "alpha olefin" refers to any straight-chain or branched carbon and hydrogen compound having at least one double bond between an α-carbon atom and a β-carbon atom. For purposes of this specification and its appended claims, when a polymer or copolymer is described as comprising an α-olefin, e.g., a poly-α-olefin, the α-olefin present in such a polymer or copolymer is the polymerized form of the α-olefin.

[0013] A detailed description of expanded propylene-based elastomers and methods of using same is provided herein. Each of the appended claims defines a separate invention, and for infringement purposes, it is recognized that it includes equivalents to the various elements or limitations set forth in the claims. Depending on the context, all references to the "invention" may, in some cases, refer to only certain embodiments. In other cases, it will be recognized that references to the "invention" refer to the subject matter recited in one or more, but not necessarily all, claims. Each of the inventions, including specific embodiments, versions, and examples, is described in more detail below; however, the invention is not limited to these embodiments, versions, or examples, which, when combined with publicly available information and technology, are included to enable one of ordinary skill in the art to make and use the invention. The foamed composition can be injection molded or compression molded into the desired shape and then physically foamed by one or more chemical or physical foaming techniques. The foamed composition can also be produced by single-screw compounding, twin-screw compounding, kneader / Banbury mixing, or similar techniques. The foamed products provided herein are lighter and less dense than mechanically equivalent products made from expanded polypropylene, polystyrene, or RCP, making them particularly useful for footwear such as slippers or midsoles; packaging; yoga mats; and other consumer products.

[0014] The foam composition may be or may include a blend or two or more propylene-based elastomers and one or more polypropylenes. The propylene-based elastomer is a random copolymer having crystalline regions interrupted by amorphous regions, with ethylene or C4-C10 α-olefin-derived units in the range of 5-25 wt. % of the propylene-based elastomer's mass, and may be diene-derived units, with the remainder of the polymer being propylene-derived units. Without intending to be limited by any theory, it is believed that the amorphous regions may result from regions of amorphous polypropylene segments and / or the inclusion of comonomer units. The crystallinity and melting point of the propylene-based elastomer, compared to highly isotactic polypropylene, are reduced by the introduction of errors in propylene insertion (steric and regio-defects) and / or the presence of comonomers. The copolymer contains at least 60 wt. % propylene-derived units, based on the mass of the propylene-based elastomer. In some embodiments, the propylene-based elastomer is a propylene-based elastomer having limited crystallinity due to adjacent isotactic propylene units and a melting point as described herein. In other embodiments, the propylene-based elastomer generally does not have any substantial intermolecular heterogeneity in tacticity and comonomer composition, and generally does not have any substantial heterogeneity in intramolecular composition distribution.

[0015] In certain embodiments, the PBE contains at least 60% by weight of propylene and 5% to about 30% by weight of one or more alpha-olefin-derived units, such as ethylene and / or a C4-C12 α-olefin. In some examples, the alpha-olefin-derived units, or comonomer, can be ethylene, butene, pentene, hexene, 4-methyl-1-pentene, octene, or decene. In one or more examples, the comonomer is ethylene. In some embodiments, the PBE consists essentially of propylene and ethylene, or consists only of propylene and ethylene. While some of the embodiments described below are discussed with respect to ethylene as the comonomer, the embodiments are equally applicable to PBEs having other α-olefin comonomers. In this regard, with respect to ethylene as the α-olefin, the copolymer may be simply referred to as a PBE. The comonomer may be ethylene, 1-hexene, or 1-octene, preferably in an amount of 3, 5, 10, or 14 weight percent to 15, 20, 22, or 25 weight percent, based on the total weight of the propylene-based elastomer. The comonomer content of the propylene-based elastomer may range from about 3 to about 35 weight percent; about 3 to 15 weight percent; and about 10 to 15 weight percent, based on the total weight of the propylene-based elastomer.

[0016] The propylene-based elastomer may contain 3, 5, 10, or 14 weight percent to 15, 20, 22, or 25 weight percent ethylene-derived units, based on the total weight of the propylene-based elastomer. The ethylene content of the propylene-based elastomer may range from about 3 to about 35 weight percent; about 3 to 15 weight percent; and about 10 to 15 weight percent, based on the total weight of the propylene-based elastomer. In any embodiment, the propylene-based elastomer consists essentially of propylene and ethylene-derived units, i.e., the propylene-based elastomer does not contain any other comonomers in amounts typically present as impurities in the ethylene and / or propylene input streams used during polymerization, or in amounts that significantly affect the heat of fusion, melting point, crystallinity, or melt flow rate of the propylene-based elastomer, or any other comonomers intentionally added to the polymerization process. The diene comonomer unit may be included in the propylene-based elastomer. Examples of suitable dienes include, but are not limited to, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, divinylbenzene, 1,4-hexadiene, 5-methylene-2-norbornene, 1,6-octadiene, 5-methyl-1,4-hexadiene, 3,7-dimethyl-1,6-octadiene, 1,3-cyclopentadiene, 1,4-cyclohexadiene, dicyclopentadiene, or combinations thereof. The amount of diene comonomer may be 0 wt%, or 0.5 wt%, or 1 wt%, or 1.5 wt% or more, and 5 wt%, or 4 wt%, or 3 wt%, or 2 wt% or less, based on the mass of the propylene-based elastomer.

[0017] The PBE can comprise at least about 5 wt%, at least about 6 wt%, at least about 7 wt%, at least about 8 wt%, at least about 9 wt%, at least about 10 wt%, at least about 12 wt%, or at least about 15 wt% of α-olefin-derived units, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units. The PBE can comprise up to about 30 wt%, up to about 25 wt%, up to about 22 wt%, up to about 20 wt%, up to about 19 wt%, up to about 18 wt%, or up to about 17 wt% of α-olefin-derived units, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units. In some embodiments, the PBE can contain about 5% to about 30%, about 6% to about 25%, about 7% to about 20%, about 10% to about 19%, about 12% to about 18%, or about 15% to about 17% by weight of α-olefin-derived units, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units. The PBE can comprise at least 50 wt%, at least 70 wt%, at least 75 wt%, at least 78 wt%, at least 80 wt%, at least 81 wt%, at least 82 wt%, or at least 83 wt% propylene-derived units, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units. The PBE can comprise up to about 95 wt%, up to about 94 wt%, up to about 93 wt%, up to about 92 wt%, up to about 91 wt%, up to about 90 wt%, up to about 88 wt%, or up to about 85 wt% propylene-derived units, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units.

[0018] PBEs can be characterized by their melting point (Tm), which can be determined by differential scanning calorimetry (DSC). For purposes of this specification, the maximum of the highest temperature peak is considered the melting point of the polymer. A "peak," in this context, is defined as a change from positive to negative in the general slope of the DSC curve (heat flow versus temperature) that forms a maximum without a shift in the baseline along which the DSC curve is plotted, with an endothermic reaction indicated by a positive peak. The Tm of a PBE (determined by DSC) can be less than 120°C, less than 115°C, less than 110°C, or less than 105°C. The PBE can be characterized by its heat of fusion (Hf) as determined by DSC. The PBE can have an Hf that is at least about 0.5 J / g, at least about 1.0 J / g, at least about 1.5 J / g, at least about 3.0 J / g, at least about 4.0 J / g, at least about 5.0 J / g, at least about 6.0 J / g, or at least about 7.0 J / g. The PBE can be characterized by an Hf of less than 75 J / g, or less than 70 J / g, or less than 60 J / g, or less than 50 J / g. In one or more examples, the PBE has a melting temperature of less than 120° C. and a heat of fusion of less than 75 J / g.

[0019] As used herein, the DSC procedure for determining Tm and Hf is as follows: The polymer is compressed in a heated press at a temperature of about 200°C to about 230°C, and the resulting polymer sheet is suspended under ambient conditions and cooled in air. A sample of about 6 mg to about 10 mg of the polymer sheet is removed with a punch die. The sample is annealed at room temperature (about 23°C) for about 80 hours to about 100 hours. At the end of the annealing period, the sample is placed in a DSC (Perkin Elmer Pyris One Thermal Analysis System) and cooled to about -30°C to about -50°C and held at this temperature for 10 minutes. The sample is then heated at 10°C / min until a final temperature of about 200°C is reached. The sample is held at 200°C for 5 minutes. A second cooling-heating cycle is then performed, where the sample is cooled again to about -30°C to about -50°C, held at this temperature for 10 minutes, and then reheated at 10°C / min to a final temperature of about 200°C. The progress from both cycles is recorded. The heat output is recorded as the area under the melting peak of the sample, which typically occurs between about 0°C and about 200°C. It is measured in Joules and is a measure of the Hf of the polymer. The PBE may have a triad tacticity (mm tacticity) of three propylene units of 75% or more, 80% or more, 85% or more, 90% or more, 92% or more, 95% or more, or 97% or more, as measured by C NMR. For example, the triad tacticity may range from about 75% to about 99%, about 80% to about 99%, about 85% to about 99%, about 90% to about 99%, about 90% to about 97%, or about 80% to about 97%. Triad tacticity may be determined by the method described in U.S. Pat. No. 7,232,871.

[0020] The PBE may have a tacticity index m / r ranging from a lower limit of 4 or 6 to an upper limit of 8, 10, or 12. The tacticity index, designated herein as "m / r," is determined by C nuclear magnetic resonance ("NMR"). The tacticity index m / r is calculated as defined in H.N. Cheng, Vol. 17, MACROMOLECULES, pp. 1950-1955 (1984), which is incorporated herein by reference. The designations "m" and "r" describe the stereochemistry of pairs of adjacent propylene groups, with "m" representing meso and "r" representing racemic. An m / r ratio of 1.0 generally indicates a syndiotactic polymer, and an m / r ratio of 2.0 indicates an atactic material. The PBE may have a percent crystallinity of about 0.5% to about 40%, about 1% to about 30%, or about 5% to about 25%, as determined according to DSC procedures. Crystallinity can be determined by dividing the Hf of the sample by the Hf of a 100% crystalline polymer, which is estimated to be 189 J / g for isotactic polypropylene. The PBE can have a density at room temperature (about 23° C.) of about 0.84 g / cm to about 0.92 g / cm, about 0.85 g / cm to about 0.90 g / cm, or about 0.85 g / cm to about 0.87 g / cm, as measured by ASTM D-1505 test method.

[0021] The PBE can have a melt index (MI) (ASTM D-1238, 2.16 kg @ 190°C) of about 100 dg / min or less, about 50 dg / min or less, about 25 dg / min or less, about 10 dg / min or less, about 8.0 dg / min or less, about 5.0 dg / min or less, or about 3.0 dg / min or less. The PBE may have a melt flow rate (MFR) of greater than 0.5 dg / min, greater than 1.0 dg / min, greater than 1.5 dg / min, greater than 2.0 dg / min, or greater than 2.5 dg / min, as measured in accordance with ASTM D-1238 (230°C, 2.16 kg load). The PBE may have an MFR of less than 100 dg / min, less than 50 dg / min, less than 25 dg / min, less than 15 dg / min, less than 10 dg / min, less than 7 dg / min, or less than 5 dg / min. In some embodiments, the PBE may have an MFR of about 0.5 to about 10 dg / min, about 1.0 to about 7 dg / min, or about 1.5 to about 5 dg / min.

[0022] The PBE may have a g' index value of 0.95 or greater, or at least 0.97, or at least 0.99, where g' is measured at the Mw of the polymer using the intrinsic viscosity of isotactic polypropylene as the reference. For use herein, the g' index is defined as: g' = η / η, where η is the intrinsic viscosity of the polymer and η is the intrinsic viscosity of a linear polymer of the same viscosity-average molecular weight (Mv) as the polymer. η = KMα, where K and α are measurements on a linear polymer and should be obtained on the same instrument as used for the g' index measurement. The PBE can have a weight average molecular weight (Mw) of about 50,000 to about 1,000,000 g / mol, or about 75,000 to about 500,000 g / mol, about 100,000 to about 350,000 g / mol, about 125,000 to about 300,000 g / mol, about 150,000 to about 275,000 g / mol, or about 200,000 to about 250,000 g / mol, as measured by DRI. The PBE can have a number average molecular weight (Mn) of about 5,000 to about 500,000 g / mol, about 10,000 to about 300,000 g / mol, about 50,000 to about 250,000 g / mol, about 75,000 to about 200,000 g / mol, or about 100,000 to about 150,000 g / mol, as measured by DRI.

[0023] The PBE can have a z-average molecular weight (Mz), as measured by MALLS, of about 50,000 to about 1,000,000 g / mol, or about 75,000 to about 500,000 g / mol, or about 100,000 to about 400,000 g / mol, or about 200,000 to about 375,000 g / mol, or about 250,000 to about 350,000 g / mol. The molecular weight distribution (MWD, equal to Mw / Mn) of the PBE can be from about 0.5 to about 20, from about 0.75 to about 10, from about 1.0 to about 5, from about 1.5 to about 4, or from about 1.8 to about 3.

[0024] The PBE may also include one or more dienes. The term "diene" is defined as a hydrocarbon compound having two sites of unsaturation, e.g., a compound having two double bonds attached to a carbon atom. Depending on the context, the term "diene," as used herein, broadly refers to either the diene monomer prior to polymerization, e.g., as a forming part of the polymerization medium, or the diene monomer (also referred to as a diene monomer unit or a diene-derived unit) after polymerization has begun. In some embodiments, the diene may be selected from 5-ethylidene-2-norbornene (ENB); 1,4-hexadiene; 5-methylene-2-norbornene (MNB); 1,6-octadiene; 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene; 1,3-cyclopentadiene; 1,4-cyclohexadiene; vinylnorbornene (VNB); dicyclopentadiene (DCPD), and combinations thereof. In embodiments where the PBE composition contains a diene, the diene may be present from 0.05 wt % to about 6 wt %, from about 0.1 wt % to about 5.0 wt %, from about 0.25 wt % to about 3.0 wt %, or from about 0.5 wt % to about 1.5 wt % of diene-derived units, where the weight percentages are based on the total weight of the propylene-derived, α-olefin-derived, and diene-derived units.

[0025] The PBE may be grafted (e.g., "functionalized") with one or more grafting monomers. As used herein, the term "grafting" refers to the covalent attachment of a grafting monomer to the polymer chain of the PBE. The grafting monomer may be or include at least one ethylenically unsaturated carboxylic acid or acid derivative, such as an anhydride, ester, salt, amide, imide, or acrylate. Exemplary grafting monomers include, but are not limited to, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohexene-1,2-dicarboxylic anhydride, bicyclo(2.2.2)octene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-oxa-1,3-diketospiro(4.4)nonene, bicyclo(2.2.1)heptene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, norbornene-2,3-dicarboxylic anhydride, nadic anhydride, methylnadic anhydride, himic anhydride, methylhimic anhydride, and 5-methylbicyclo(2.2.1)heptene-2,3-dicarboxylic anhydride. Other suitable grafting monomers include methyl and higher alkyl acrylates, methyl and higher alkyl methacrylates, acrylic acid, methacrylic acid, hydroxy-methyl methacrylate, hydroxyl-ethyl and higher hydroxy-alkyl methacrylates, and glycidyl methacrylate. Maleic anhydride is a grafting monomer. In embodiments, the grafting monomer may be or include maleic anhydride, and the concentration of maleic anhydride in the grafted polymer is in the range of about 1% to about 6% by weight, such as at least about 0.5% by weight, or at least about 1.5% by weight.

[0026] In some embodiments, the PBE is a reactor blend polymer. That is, the PBE is a reactor blend of a first polymer component and a second polymer component. Thus, the comonomer content of the PBE can be adjusted by adjusting the comonomer content of the first polymer component, adjusting the comonomer content of the second polymer component, and / or adjusting the ratio of the first polymer component to the second polymer component present in the PBE. In embodiments where the PBE is a reactor blend polymer, the α-olefin content of the first polymer component can be greater than 5 wt% α-olefin, greater than 7 wt% α-olefin, greater than 10 wt% α-olefin, greater than 12 wt% α-olefin, greater than 15 wt% α-olefin, or greater than 17 wt% α-olefin, where the weight percentages are based on the total weight of propylene-derived and α-olefin-derived units of the first polymer component. The α-olefin content of the first polymer component can be less than 30 wt% α-olefin, less than 27 wt% α-olefin, less than 25 wt% α-olefin, less than 22 wt% α-olefin, less than 20 wt% α-olefin, or less than 19 wt% α-olefin, where the weight percentages are based on the total weight of propylene-derived and α-olefin-derived units of the first polymer component. In some embodiments, the α-olefin content of the first polymer component can range from 5% to 30% by weight α-olefin, 7% to 27% by weight α-olefin, 10% to 25% by weight α-olefin, 12% to 22% by weight α-olefin, 15% to 20% by weight α-olefin, or 17% to 19% by weight α-olefin. In some examples, the first polymer component contains or comprises propylene and ethylene, and in some embodiments, the first polymer component consists exclusively of units derived from propylene and ethylene.

[0027] In embodiments where the PBE is a reactor blend polymer, the α-olefin content of the second polymer component can be greater than 1.0 wt% α-olefin, greater than 1.5 wt% α-olefin, greater than 2.0 wt% α-olefin, greater than 2.5 wt% α-olefin, greater than 2.75 wt% α-olefin, or greater than 3.0 wt% α-olefin, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units of the second polymer component. The α-olefin content of the second polymer component can be less than 10 wt% α-olefin, less than 9 wt% α-olefin, less than 8 wt% α-olefin, less than 7 wt% α-olefin, less than 6 wt% α-olefin, or less than 5 wt% α-olefin, where the weight percentages are based on the total weight of the propylene-derived and α-olefin-derived units of the second polymer component. In some embodiments, the α-olefin content of the second polymer component can range from 1.0 wt% to 10 wt% α-olefin, or 1.5 wt% to 9 wt% α-olefin, or 2.0 wt% to 8 wt% α-olefin, or 2.5 wt% to 7 wt% α-olefin, or 2.75 wt% to 6 wt% α-olefin, or 3 wt% to 5 wt% α-olefin. In some examples, the second polymer component contains propylene and ethylene, and in some embodiments, the first polymer component consists exclusively of units derived from propylene and ethylene.

[0028] In certain embodiments, the PBE contains propylene-derived units and about 5% to about 30% by weight of α-olefin-derived units, and has a melting temperature of less than 120° C. and a heat of fusion of less than 75 J / g. In certain embodiments, the PBE contains propylene-derived units and from about 15% to about 30% by weight of one or more alpha-olefin-derived units, and has a MFR of at least 40 dg / min and a heat of fusion (Hf) of from about 3 J / g to about 75 J / g, as determined by DSC. In embodiments where the PBE is a reactor blend polymer, the PBE may contain, based on the weight of the PBE, 1% to 25% by weight of the second polymer component, 3% to 20% by weight of the second polymer component, 5% to 18% by weight of the second polymer component, 7% to 15% by weight of the second polymer component, or 8% to 12% by weight of the second polymer component. The PBE may contain, based on the weight of the PBE, 75% to 99% by weight of the first polymer component, 80% to 97% by weight of the first polymer component, 85% to 93% by weight of the first polymer component, or 82% to 92% by weight of the first polymer component.

[0029] In one or more embodiments, the PBE comprises a reactor blend of a first polymer component and a second polymer component. The first polymer component comprises propylene and an α-olefin and has an α-olefin content of greater than 5 wt% to less than 30 wt% α-olefin, based on the total weight of the propylene-derived and α-olefin-derived units of the first polymer component. The second polymer component comprises propylene and an α-olefin and has an α-olefin content of greater than 1 wt% to less than 10 wt% α-olefin, based on the total weight of the propylene-derived and α-olefin-derived units of the second polymer component. In one or more examples, the first polymer component has an α-olefin content of about 10 wt% to about 25 wt% α-olefin, based on the total weight of the propylene-derived and α-olefin-derived units of the first polymer component. The second polymer component has an α-olefin content of greater than 2 wt% to less than 8 wt% α-olefin, based on the total weight of the propylene-derived and α-olefin-derived units of the second polymer component. In another example, the PBE contains from about 1% to about 25% by weight of the second polymer component and from about 75% to about 99% by weight of the first polymer component, based on the weight of the PBE.

[0030] PBEs can be prepared by any suitable means known in the art. PBEs can be prepared using homogeneous conditions, such as a continuous solution polymerization process, using a metallocene catalyst. In some embodiments, PBEs are prepared in parallel solution polymerization reactors, such that a first reactor component is prepared in a first reactor and a second reactor component is prepared in a second reactor, and the reactor effluents from the first and second reactors are combined and blended to form a single effluent from which the final PBE is isolated. Exemplary methods for PBE preparation can be found in U.S. Patent Nos. 6,881,800; 7,803,876; 8,013,069; and 8,026,323, and PCT Publication Nos. WO 2011 / 087729; WO 2011 / 087730; and WO 2011 / 087731.

[0031] polypropylene The terms "polypropylene," "propylene polymer," and "propylene-based polymer" refer to a polymer or copolymer containing at least 50 mol% propylene units (preferably at least 70 mol% propylene units, more preferably at least 80 mol% propylene units, even more preferably at least 90 mol% propylene units, and even more preferably at least 95 mol% propylene units or 100 mol% propylene units (in the case of a homopolymer)). The polypropylene may be or include homopolypropylene ("hPP"), isotactic polypropylene, highly isotactic polypropylene, syndiotactic polypropylene, as well as copolymers of propylene or mixtures thereof. Products including one or more propylene monomers polymerized with one or more additional monomers may be more commonly known as random copolymers (RCPs) or impact copolymers (ICPs). Impact copolymers may also be known in the art as heterophasic copolymers. "Propylene-based," as used herein, means including any polymer containing propylene, either alone or in combination with one or more comonomers, wherein propylene is the major component (e.g., greater than 50% by weight propylene).

[0032] The term "random polypropylene" as used herein broadly refers to a single-phase copolymer of propylene with up to 9% by weight, preferably 2% to 8% by weight, of an alpha-olefin comonomer. Preferred alpha-olefin comonomers have 2 carbon atoms, or 4 to 12 carbon atoms. Preferably, the alpha-olefin comonomer is ethylene. "Reactor grade," as used herein, means polymers that have not been chemically or mechanically treated or blended after polymerization in an attempt to alter the average molecular weight, molecular weight distribution, or viscosity of the polymer. Specifically excluded from those polymers described as reactor grade are those that have been visbroken or otherwise treated or coated with peroxides or other decomposition-promoting agents. However, for purposes of this disclosure, reactor grade polymers include those polymers that are reactor blends. The weight average molecular weight (Mw) of the polypropylene may be 50,000 to 3,000,000 g / mol, or 90,000 to 500,000 g / mol, with a molecular weight distribution (MWD, Mw / Mn) within the range of 1.5 to 2.5, 3.0, 4.0, 5.0, or 20.0. The polypropylene may have a MFR (2.16 kg / 230°C) within the range of 10, 15, 18, 30, 35, 40, or 50 dg / min.

[0033] foaming agent The blowing agent may include, but is not limited to, decomposable chemical blowing agents and physical blowing agents. Physical blowing agents may include gases such as air, nitrogen, carbon dioxide, etc., which may be injected into the composition during the injection molding process. Chemical blowing agents decompose at elevated temperatures to form gases or vapors that expand the polymer into a foam-like form. Suitable chemical blowing agents may include, but are not limited to, organic blowing agents such as 4,4'-oxybisbenzenesulfonylhydrazide; azodicarbonamide; azobisformamide; azobisisobutyronitrile; diazoaminobenzene; N,N-dimethyl-N,N-dinitrosoterephthalamide; N,N-dinitrosopentamethylenetetraamine; benzenesulfonylhydrazide; benzene-1,3-disulfonylhydrazide; diphenylsulfone-3,3,disulfonylhydrazide; p-toluenesulfonylsemicarbizide; barium azodicarboxylate; butylamine nitrile; nitrourea; trihydrazinotriazine; phenyl-methyl-uranate; p-sulfonhydrazide; peroxides, and the like; and inorganic blowing agents such as ammonium bicarbonate and sodium bicarbonate.

[0034] The blowing agent may be utilized in an amount of about 25% by weight or less, about 20% by weight or less, about 15% by weight or less, about 10% by weight or less, or about 6% by weight or less, based on the total amount of polymer being foamed. In some embodiments, the blowing agent may be used in an amount of about 0.1% to 25% by weight, about 0.2% to 20% by weight, about 0.3% to 15% by weight, about 0.4% to 10% by weight, or 0.5% to about 6% by weight, based on the total amount of PBE and copolymer being foamed. The foam compositions may be produced or formed by any useful discrete molding or continuous extrusion means known in the art for forming and shaping polyolefins, including single screw compounding, twin screw compounding, kneader / Banbury mixing, sheet extrusion, profile extrusion or coextrusion, compression molding, injection molding, co-injection molding, gas-assisted injection molding, transfer molding, foam molding, transfer molding, vacuum forming, laminating, calendering, or other processing types. In one embodiment, the composition can be extruded from an extruder into pellets, a sheet-like shape, or the like (molding step), and the extruded composition can be heated and foamed (foaming step). During the foaming step, the composition can be inserted into a preheated chamber or autoclave at a temperature ranging from 40 to 200°C, or from 60 to 160°C, for example, and then heated at a temperature ranging from 450°C or less, or from 100 to 400°C, or from 120 to 350°C, for example, from 1 to 80 minutes, or from 2 to 50 minutes, or from 1 minute to 10 hours, or from about 0.5 hours to 8 hours, or from about 1 hour to about 6 hours, or from 2 hours to 6 hours. Alternatively, the prepared composition can be molded into a sheet-like shape using a press and foamed upon opening the press while heating (foaming step).

[0035] FIG. 1 illustrates an example apparatus 100 for forming foamed beads from extruded pellets. The pellets and water are enclosed in a high-pressure stainless steel vessel 102 equipped with a heating system 104. In one embodiment, the water inside the vessel 102 acts as a heat transfer medium. The pellets and water are agitated by an agitator 106. A gas, such as CO2, is introduced into the vessel through an outlet 108 to reach a desired pressure inside the vessel. The vessel 102 is then heated to a target temperature by the heater 104. The vessel 102 is held at the target temperature for a period of time to allow gas saturation. The vessel 102 is then depressurized by opening a shutoff valve 110, and the foamed beads are obtained in a collection device 112. Other examples of molding and foaming processes are disclosed in U.S. Patent Application Publication No. 20200181350. Due to its relatively low molecular weight and thermoplasticity, the propylene-based elastomer in the compositions described herein promotes gas expansion during the foaming process, creating larger open cells, thereby reducing the density of foamed products made therefrom.

[0036] The compositions described herein may comprise at least 20% by weight of one or more PBEs, based on the total weight of the composition. The compositions may also comprise at least 22%, at least 25%, at least 30%, at least 40%, or at least 50% by weight of one or more PBEs, based on the total weight of the composition. The compositions may also contain one or more PBEs in amounts ranging from as low as about 20%, 25%, or 30% by weight to as high as about 75%, 85%, or 95% by weight, with the remainder being one or more polypropylenes. In some embodiments, the compositions comprise one or more propylene-based elastomers in an amount of at least 20 wt. %, based on the total weight of the composition, to provide foamed products made therefrom that have densities (ASTM D792-08, 23° C.) that are at least 5%, at least 7%, at least 10%, or at least 12% lower than the densities of comparable foamed products made from polystyrene, polypropylene, or RCP. The composition may have a flexural modulus (ISO 178) of at least 200 MPa. The flexural modulus may also be at least 300 MPa, at least 500 MPa, at least 700 MPa, at least 900 MPa, at least 1100 MPa, or at least 1300 MPa. The flexural modulus may also range from a low of about 300, 500, or 600 to a high of about 800, 1000, or 1500 MPa. The composition has a flexural modulus of at least 5 KJ / m at 23°C. 2 The tensile strength may have a notched Izod impact (ISO 180) of at least 10 MPa based on ISO 527, a tensile yield stress of at least 10 MPa, and a tensile yield strain of at least 4%.

[0037] The composition may have a Vicat softening point (ASTM D 1525-07) of at least 45° C., at least 50° C., at least 60° C., at least 80° C., at least 95° C., at least 110° C., at least 130° C., or at least 150° C. The Vicat softening point may also range from a low of about 45, 50, 60, 80, 100, or 115 to a high of about 130, 150, or 170° C. The composition may also have any combination of two or more of the aforementioned density, flexural modulus (ISO 178), Vicat softening point (ASTM D 1525-07), notched Izod impact (ISO 180), and tensile yield stress and tensile yield strain according to ISO 527. The expanded beads produced using the compositions described herein may have an average cell size of about 3 mm or less, preferably about 2 mm or less, preferably 1 mm or less, according to ASTM D3576-04. Alternatively, the cell size may be 10 μm to 10 mm, preferably 100 μm to 5 mm.

[0038] Expandable foam beads ("EFB") produced from the compositions provided herein have a viscosity of 0.140 g / cm 3 The EFB may have a density of preferably 0.135, 0.130, 0.120, or 0.110 g / cm 3 The EFB has a density of less than about 0.03, 0.05, 0.07, or 0.08 g / cm 3 from a low of about 0.11, 0.12, 0.10, or 0.14 g / cm 3 The density may range from 0.1 to as high as 0.1. In the above detailed description, specific embodiments of the present disclosure have been described in connection with their preferred embodiments. However, to the extent that the above description is specific to a particular embodiment or particular use of the present disclosure, it is intended for illustrative purposes only and merely provides a concise description of exemplary embodiments. Therefore, the present disclosure is not limited to the specific embodiments described above; rather, the present disclosure includes all alternatives, modifications, and equivalents that fall within the true scope of the appended claims. Various modifications and variations of the present disclosure will be apparent to those skilled in the art, and it is to be understood that such modifications and variations are within the spirit and scope of the present application and the claims. [Example]

[0039] The embodiments discussed and illustrated herein may be further illustrated in the following examples, which relate to specific embodiments but should not be considered limiting in any way. Example 1 Two plate sheets were injection molded and then foamed to test the physical properties of the unblended polymer. Sheet No. 1 had a melt index of 3 g / 10 min and a viscosity of 0.862 g / cm at 230°C / 2.16 kg. 3 Sheet No. 2 was made from a first propylene-based copolymer (PBE1) obtained from ExxonMobil, having a melt index of 8 g / 10 min at 230° C. / 2.16 kg and a viscosity of 0.879 g / cm 3 . 3 The composite was made from a second propylene-based copolymer (PBE2) having a density of 1000 .mu.m.sup.2 and also obtained from ExxonMobil.

[0040] The polymer is injection molded into a plate, and Wuxi Jinhe The mixture was then inserted into a preheated mold of a compression-type foaming machine. Table 1 summarizes the processing parameters and conditions. [Table 1] FIG. 2A shows an SEM of foam sheet No. 1, and FIG. 2B is an enlarged view of the SEM shown in FIG. 2A.

[0041] Example 2 Expandable foam beads ("EFB") were also prepared. The polymer component used in these EFBs had a melt index of 8 g / 10 min at 230°C / 2.16 kg and a melt strength of 0.879 g / cm 3 a second propylene-based copolymer (PBE2) obtained from ExxonMobil having a density of 0.889 g / cm 3 at 230°C / 2.16 kg and a melt index of 8 g / 10 min; 3 a third propylene-based copolymer (PBE3) obtained from ExxonMobil, having a melt index of 3 g / 10 min at 230° C. / 2.16 kg; a polypropylene homopolymer (hPP, trade name PP T30S) obtained from Sinopec, having a melt index of 7 g / 10 min at 230° C. / 2.16 kg and a viscosity of 0.90 g / cm 3 The polymers were random copolymers (RCP, trade name W331) obtained from TPC, having a density of 1000 MPa (1000 psi). Table 2 below reports the EFB blend and flexural modulus (ISO 178) for each polymer formulation before foaming, as well as the Vicat softening point (ASTM D 1525-07). Table 3 reports the notched Izod impact (ISO 180), tensile stress at yield and tensile strain at yield per ISO 527 for each polymer formulation.

[0042] [Table 2]

[0043] [Table 3]

[0044] Figures 3, 4, and 5 show DSC curves (based on ASTM D 3418) for samples EFB-003, EFB-006, and EFB-013. According to the curves, both EFB-003 and EFB-006 samples had melting peaks at approximately 165°C, while EFB-013 sample had a melting peak at approximately 150°C. Samples EFB003, EFB-006, and EFB-013 were selected for industrial expanded foam bead trials and steam molding trials. Each of EFB003, EFB-006, and EFB-013 was first compounded using a twin-screw extruder. The compounded materials were then pelletized into micropellets with a width of approximately 1 mm and a length of approximately 1.2 mm. The micropellets of EFB003, EFB-006, and EFB-013 were then expanded into beads using an autoclave. Carbon dioxide was used as the blowing agent.

[0045] [Table 4]

[0046] The foamed beads were then molded using steam at different pressures. Figure 6 shows photographs of EFB-003 and EFB-006 samples after steam molding at 1.6 bar. Note that the EFB-003 sample has a better surface compared to the EFB-006 sample. This indicates that EFB-003 is more suitable for molding at this 1.6 bar steam pressure. Figure 7 shows a photograph of EFB-013 sample after steam molding at 1.4 bar. Additionally, this significant reduction in steam pressure compared to the typical 2-3 bar required for conventional ethylene-propylene copolymer products results in significant cost savings. The steam-formed EFB-003 and EFB-013 samples were tested for mechanical performance at a steam pressure of 1.8 bar. Tables 5 and 6 summarize the results for compressive strength (based on GB / T 8813) and tensile properties (based on GB / T 6344).

[0047] [Table 5] [Table 6]

[0048] Example 3 EFBs containing a single polymer component were also fabricated. The polymer component used in these EFBs was PBE3. First, PBE3 was extruded into filaments and pelletized. The pellets had a diameter of approximately 1 mm. Next, the PBE3 pellets were expanded. Water, PBE3 particles, and a separating agent were added to a foaming kettle, and all valves were closed. CO2 was injected into the foaming kettle, and then heating of the foaming kettle began. The foaming temperature was 109°C, and the foaming pressure was 3.0 MPa. When the temperature and pressure reached the set values, the discharge valve was opened. The composite particles were removed from the foaming kettle with an airflow and formed into expanded beads. The expanded beads were dried in a fluidized bed dryer at 50-80°C for 1 hour to obtain the expanded bead product. The foam density of the beads was 0.074 g / cm. 3 The foam volume expansion ratio was approximately 13.5 times. The foam particles were smooth and of sufficient size and uniformity. The melting point of PFP3 EFB was determined by differential scanning calorimetry (DSC), performed on a Perkin-Elmer DSC-7 instrument using a heating rate of 20°C / min and a temperature range of 25–150°C. Measurements were performed under a N2 atmosphere. The sample mass was 5–10 mg. As can be seen from the DSC melting curve in Figure 8, there was clear multi-stage melting behavior. The melting points were 80°C, 104°C, and 120°C, respectively, which is conducive to foam vapor formation. PFP3 EFB was fractured, and the fracture surface was observed with a PHILLIPS XL30ESEM FEG field emission scanning electron microscope. As can be seen from Figure 9, the cells were uniform. The cell size was approximately 36.7 μm, and the cell density was 3.3 × 10 8 It was.

[0049] The PBE3 EFB was then molded into plaques. The PBE3 EFB was first pre-pressed in a pre-press tank at 0.06 MPa for 6 hours and then transferred to the molding machine hopper for steam chamber formation. The molding machine was operated according to a fixed procedure to cycle through the steam chamber molding process. First, the mold was closed, and the foam beads were introduced into the mold along with air. Steam was then introduced through the mold from the left side, and then steam was introduced through the mold from the right side. Steam was added simultaneously from both sides, the sample was cooled using water, the mold was automatically opened, and finally, the sample was automatically demolded. The steam chamber molding pressure was set to 0.1-0.12 MPa, the duration of each addition step was 2-4 seconds, and the water cooling time was 150 seconds. Under these conditions, a product with good steam chamber formation was obtained, as shown in Figure 10A. The product was uniform and exhibited smooth surface characteristics. As shown in Figure 10B, the bonding between the foam beads was very good. The foam beads were well fused together, with no obvious boundaries. Therefore, in terms of steam consumption, PBE3 foam exhibited lower steam chamber molding temperatures and molding times than EPS foam, under molding conditions similar to those of EPS foam.

[0050] The mechanical properties of the steam-molded products were determined according to the method described in Chinese Standard GB 8813. The compressive strength at 25% was 0.138±0.014 MPa, at 50% was 0.235±0.022 MPa, and at 75% was 0.552±0.051 MPa. The tensile strength was 52.3±4.2 MPa, and the tensile elongation at break was 88±7%. When PBE3 polymer is used alone to form an EFB, a wide T m Due to the similarity of the chain structure between PBE3 and PP, PBE3 exhibits good miscibility with PP. This is because PBE3 increases the T of the foamed beads compared to PP alone. m This shows that the temperature can be shifted to a lower range. Therefore, PP-PBE3 foam beads can achieve good fusion under low T / low steam chest pressure, resulting in significant energy savings and reduced equipment costs.

[0051] Example 4 Expandable foam beads were produced using PBE2 and PBE3 pellets. PBE2 and PBE3 pellets and water were separately sealed in high-pressure stainless steel vessels equipped with a heating system. Water was used as the heat transfer medium. CO2 was added to the vessel at an appropriate stirring speed of 200 r / min to reach the desired pressure. The chamber was then heated to the target temperature. The chamber was maintained at the target temperature for a certain period of time until saturated with CO2. The pressure was then reduced by opening the shut-off valve, and the bead foam was obtained in a collection device. DSC was used to investigate the thermal behavior of expanded PBE beads. As shown for PBE3 in Figure 11, two clear endothermic peaks were observed in the first heating curve (line 1101). The lower peak at 108 °C is relatively broader than the higher peak at 121 °C. In contrast, the second heating curve (line 1102), which provides information on the polymer in its original state without thermal history, shows only one peak at 107 °C. The difference between the first and second melting curves indicates two crystalline structures with different stabilities formed during the expansion process. This result indicates that the stream compression molding process can target the lower melting peak, resulting in the expanded beads undergoing partial surface melting and then fusing together while retaining their original shape.

[0052] Similarly, the same phenomenon is observed in the DSC curve of PBE2 in Figure 12. For the first heating curve (line 1201), the lower peak is at approximately 107°C and the higher peak is at 116°C. In contrast, for the second heating curve (line 1202), the melting point of the pristine polymer is 107°C. The results show that both foamed PBE2 and PBE3 can form two melting peaks, which is important for the subsequent stream compression molding process. A simple experiment was designed to simulate the molding process, as shown in Figure 13. Expanded PBE beads were fully packed into a stainless steel can with a screw cap. After the lid was tightly fastened, the expanded beads were in a compressed state. The can was then placed in a constant temperature oven for a short time and then removed from the oven to cool. The molded beads were then removed from the can and examined for fusion quality and appearance. PBE3 was held in the oven at 110°C for 7 minutes. PBE2 was held in the oven at 95°C for 6 minutes. This example shows that for PBE2 and PBE3, the foamed pellets exhibit double-peak melting behavior that can be used to define a target temperature window for compression molding, within which the surfaces of the foamed beads adhere together while the structure of the foamed beads is maintained.

[0053] All patents and patent applications, test procedures (ASTM methods, UL methods, etc.), and other documents cited herein are incorporated by reference in their entirety to the extent such disclosure does not contradict this disclosure and for all rights where such incorporation is permitted. Certain embodiments and features have been described using sets of upper and lower numerical limits. It should be understood that ranges including combinations of any two values, for example, any lower value with any higher value, any two lower values, and / or any two higher values, are contemplated unless otherwise indicated. Certain lower limits, upper limits, and ranges appear in one or more claims below. All numerical values ​​are expressed as "about" or "approximately," meaning that the value takes into account experimental error, machine tolerances, and other variations that would be expected by one of ordinary skill in the art. The above also outlines some of the features of certain embodiments to enable those skilled in the art to better understand the present disclosure. Those skilled in the art will appreciate that they can readily use the present disclosure as a basis for designing or modifying other methods or apparatuses to carry out the same purposes and / or achieve the same advantages as the embodiments disclosed herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the present disclosure, the scope of which is determined by the following claims.

[0054] Various terms have been defined above. Unless a term used in the claims is defined above, that term should be given the broadest definition given to it by one of the relevant arts as set forth in at least one publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are incorporated by reference in their entirety to the extent such disclosure is not inconsistent with this application and to all authorities to which such incorporation is permitted. The foregoing is directed to embodiments of the present invention; other and further embodiments of the invention may be devised without departing from the basic scope thereof, which scope is determined by the following claims.

Claims

1. (a) at least 5 wt. %, based on the total weight of the composition, of at least one propylene-based elastomer comprising propylene and from about 15 wt. % to about 30 wt. % of units derived from one or more alpha-olefins, based on the total weight of the elastomer, the propylene-based elastomer having an MFR of at least 3 g / 10 min and a heat of fusion (Hf) of from about 3 J / g to about 75 J / g, as determined by DSC; (b) less than 95% by weight, based on the total weight of the composition, of at least one polypropylene; and (c) a foaming agent; Prior to combining with the blowing agent, the polymer blend has a viscosity of at least 0.80 g / cm 3 and after the blend is foamed, the foamed article has a density of 0.2 g / cm 3 1. A foamable polymer composition having a density of:

2. 10. The expandable polymer composition of claim 1, wherein the at least one propylene-based elastomer comprises at least 10% by weight of the expandable polymer composition.

3. 10. The expandable polymer composition of claim 1, wherein the at least one propylene-based elastomer comprises at least 20% by weight of the expandable polymer composition.

4. 10. The expandable polymer composition of claim 1, wherein the blowing agent is a gas.

5. 10. The expandable polymer composition of claim 1, wherein the blowing agent is carbon dioxide.

6. 10. The expandable polymer composition of claim 1, wherein the polypropylene comprises at least 70% by weight of propylene-derived units.

7. 1. The expanded beads comprising at least 80 wt. % of at least one propylene-based elastomer, based on the total weight of the expanded beads, comprising propylene and about 15 wt. % to about 30 wt. % of units derived from one or more alpha-olefins, based on the total weight of the elastomer, wherein the propylene-based elastomer has an MFR of at least 3 g / 10 min and a heat of fusion (Hf) of about 3 J / g to about 75 J / g, as determined by DSC.

8. 8. The expanded beads of claim 7, further comprising a blowing agent.

9. 8. The expanded beads of claim 7 having a melting temperature of less than 111°C.

10. 8. The expanded beads of claim 7, having a melting temperature of 100 to 111°C.

11. An article comprising a plurality of the foam beads of claim 7.

12. 1. A method of producing a foamed polymer composition, comprising: (a) mixing a blowing agent with a molten polymer composition to form a foamable mixture; (b) forming the foamable mixture such that the blowing agent expands within the mixture to produce a foam; (c) 0.11g / cm 3 and obtaining a foamed article having a density of:

13. 13. The method of claim 12, wherein the foamed article has an average cell size of 1 mm or less.

14. 1. A method of producing an expanded bead article, comprising: introducing a plurality of foam beads into a mold; Increasing the pressure in the mold to a high pressure state of 0.1 to 0.5 MPa; Heating the foamed beads in the mold to an elevated temperature of 35-125°C; maintaining the high pressure and elevated temperature conditions for a compression time to form an expanded bead article; Removing the item A method comprising:

15. The method of claim 14, wherein the expanded beads are heated to a temperature of 90 to 115°C.

16. 15. The method of claim 14, wherein the expanded beads are heated to a temperature of 110°C or less.

17. The method according to claim 14, wherein the high pressure state is 0.1 to 0.12 MPa.

18. 15. The method of claim 14, wherein the compression time is 5 to 10 minutes.

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