Foamed propylene-based elastomer compositions, methods of making same, and products made therefrom

Abstract

Foamed polymer compositions and products made therefrom are disclosed. More specifically, a foamed polymer composition comprising a propylene-based elastomer. Comprising such a propylene-based elastomer requires less energy for molding without sacrificing the properties of the foamed product.

Description

[0001] Inventors : Jin Jieyu, Wang Yan, Qiu Haibin, Sheng Yujie, Li Liang, Hua Haiyan, Wang Hongchao, Wang Yaxian, Tang Tao, Li Minggang

[0002] Cross Reference to Related Applications

[0003] This application claims the benefit of U.S. Provisional Application 63 / 488,467, filed March 3, 2023, entitled Foamed Propylene-Based Elastomer Compositions, Methods for Making and Products Made Therefrom, which is incorporated herein by reference in its entirety. INVENTION FIELD

[0004] Embodiments of the present invention relate generally to foamed polymer compositions and products made therefrom. More specifically, such embodiments relate to foamed polymer compositions made from propylene-based elastomers. BACKGROUND

[0006] Expanded bead pellets are physically foamed products that are widely used in industrial packaging or automotive applications. EPP (expanded polypropylene) is commonly used to replace cardboard in the packaging industry or as part of a rear seat to reduce weight in a car. EPS (expanded polystyrene) is commonly used to protect items in packaging during shipping. EPP generally has better mechanical properties than EPS, and EPP is recyclable and reusable, which is more sustainable compared to EPS. As such, there is a trend in the industry to replace EPS and other forms of packaging with more EPP.

[0007] Currently, RCP (random copolymer) or terpolymer PP is used as a raw material to produce EPP. After the expanded beads are produced, the beads are typically steam molded. Due to the Vicat or melt temperature of EPP, the steam pressure requirement is typically 2-3 kg / cm 2 to provide the temperature needed to mold the EPP beads. The energy cost of steam can be as much as half of the total cost of the final product.

[0008] Accordingly, there is a need for expanded beads made from additional polymer materials that require less molding energy and do not sacrifice the performance of the product.

[0009] References included in the invention disclosure statement: CN105885241A, CN105885242A, CN107828134B, US2020-0181350. SUMMARY

[0011] Disclosed is a foamable polymer composition comprising at least 5 wt% of at least one propylene-based elastomer comprising propylene and about 15 wt% to about 30 wt% of one or more alpha-olefin derived units, based on the total weight of the elastomer, wherein 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 the polymer blend has a density of at least 0.80 g / cm 3 , prior to combination with the blowing agent, and the foamed article has a density of 0.2 g / cm 3 or less, after foaming of the blend.

[0012] A foamed bead comprising at least 80 wt% of a propylene-based elastomer, based on the total weight of the foamed bead, the propylene-based elastomer comprising propylene and about 15 wt% to about 30 wt% of one or more alpha-olefin derived units, based on the total weight of the elastomer, wherein 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.

[0013] A method of producing a foamed polymer composition comprising 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 obtaining a foamed article having a density of 0.11 g / cm 3 or less, wherein the molten polymer composition comprises the composition of claim 1.

[0014] A method of producing a foamed bead article comprising introducing a plurality of foamed beads into a mold, increasing the pressure within the mold to an elevated pressure of 0.1-0.5 MPa, heating the foamed beads within the mold to an elevated temperature of 35-125 °C, maintaining the elevated pressure and the elevated temperature for a compression time to form a foamed bead article, and demolding the article.

[0015] BRIEF DESCRIPTION OF DRAWINGS

[0016] So that the manner in which the above recited features of the present application can be understood in detail, a more particular description can be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this application and are therefore not to be considered limiting of its scope, for the application can admit to other equally effective embodiments. It is also to be understood that the use of terminology, such as "for example," "for instance," "as another example," or "for example," are not to be construed as limiting the scope of the application. The drawings are briefly described as follows.

[0017] Figure 1 is a schematic of a bead foaming apparatus.

[0018] Figure 2A is an SEM of the foamed sheet of Example 1.

[0019] Figure 2B is a close-up view of the SEM described in Figure 1

[0020] Figure 3 is a DSC curve of sample EFB-003.

[0021] Figure 4 is a DSC curve of sample EFB-006.

[0022] Figure 5 is a DSC curve of sample EFB-013.

[0023] Figure 6 is a photograph of a steam molded sample of (A) EFB-003 and (B) EFB-006.

[0024] Figure 7 is a photograph of a steam molded sample of EFB-013.

[0025] Figure 8 is a DSC curve of an EFB sample including PBE3.

[0026] Figure 9 is an SEM image of an EFB including PBE3.

[0027] Figure 10A is a photograph of a steam molded sample of a PBE EFB.

[0028] Figure 10B is a photograph of a cross-section of a steam molded sample of a PBE EFB.

[0029] Figure 11 is a DSC curve of an EFB including PBE3.

[0030] Figure 12 is a DSC curve of an EFB including PBE2.​

[0031] Figure 13 is a schematic illustration of a simplified compression molding process. DETAILED DESCRIPTION

[0033] It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures or functions of the present application. Exemplary embodiments are described herein in terms of components, arrangements and configurations set forth in the following description and associated drawings. Such exemplary embodiments are described in order to provide a thorough understanding of the present application. However, it will be readily recognized that the scope of the present application is not intended to be limited to or by the exemplary embodiments described herein. In addition, the present disclosure can repeat reference numerals and / or letters in the various embodiments and / or drawings. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and / or configurations discussed herein. Furthermore, the description herein of one feature or aspect of an embodiment does not indicate that it is an exhaustive or exclusive list of possible implementations of that feature or aspect. Additionally, the descriptions of the various embodiments and / or configurations are intended to be taken in conjunction with the accompanying drawings and not in isolation. In other words, the description of the various embodiments and / or configurations is intended to be taken in conjunction with the accompanying drawings and not in isolation.

[0034] In addition, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities can refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to be limiting. Furthermore, the naming convention used for the elements described herein is not intended to limit the scope of the application unless specifically recited in the claims.

[0035] In the following discussion and in the claims, the term "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to." The phrase "consisting essentially of" means that the described / claimed composition does not include components that materially alter the nature of the composition beyond this level, and in no case does it include any more than 3 mass % of any additional components.

[0036] The term "or" is intended to mean either exclusive or inclusive, i.e., "A or B" is intended to mean "at least one of A or B", unless expressly specified otherwise. The terms "a" and "an" and "the" are used interchangeably, and are intended to refer to both singular and plural, unless otherwise specifically stated. For example, the embodiment using "an olefin" includes the embodiment using one, two, or more olefins, unless expressly specified otherwise or the context clearly indicates otherwise.

[0037] The term "wt%" means percent by weight, "vol%" means percent by volume, "mol%" means percent by mole, "ppm" means parts per million and "weight ppm" and "wppm" are used interchangeably and mean parts per million on a weight basis. All concentrations herein are expressed on the basis of the total amount of the composition under discussion unless otherwise specified.

[0038] The term "polymer" means any two or more identical or different repeating unit / mer units or units. The term "homopolymer" means a polymer having identical units. The term "copolymer" means a polymer having two or more units different from each other and includes terpolymers and the like. The term "terpolymer" means a polymer having three units different from each other. The term "different" when referring to units means that the units differ from each other by at least one atom or are isomerically different. Also, as used herein, the definition of polymer includes homopolymers, copolymers and the like. By way of example, when a copolymer is said to have a "propylene" content of 10 to 30 wt%, it is to be understood that the repeating unit / mer units or simply units in the copolymer are derived from propylene in the polymerization reaction and the units are present in an amount of 10 to 30 wt% based on the weight of the copolymer.

[0039] The term "alpha-olefin" means any linear or branched carbon and hydrogen compound having at least one double bond between an alpha carbon atom and a beta carbon atom. For the purposes of this specification and the appended claims, when a polymer or copolymer is referred to as including an alpha-olefin, e.g., a polyalpha-olefin, the alpha-olefin present in such polymer or copolymer is the polymerized form of the alpha-olefin.

[0040] The nomenclature for elements and their groups used herein is in accordance with the Periodic Table as used by the International Union of Pure and Applied Chemistry since 1988. An example of the Periodic Table is shown on the inside cover of Advanced Inorganic Chemistry, 6thEdition, by F. Albert Cotton et al., John Wiley & Sons, Inc., 1999.

[0041] As used herein, the term "monomer" or "comonomer" can refer to a monomer used to form a polymer, e.g., an unreacted compound in its pre-polymerization form, and can also refer to a monomer after it has been incorporated in a polymer (also referred to herein as a "[monomer]-derived unit").

[0042] The term "copolymer" is intended to include polymers having two or more monomers, optionally with other monomers, and can refer to interpolymers, terpolymers, and the like. The term "polymer" as used herein includes, but is not limited to, homopolymers, copolymers, terpolymers, and the like, as well as alloys and blends thereof. The term "polymer" as used herein also includes impact, block, graft, random, and alternating copolymers. Unless otherwise specifically indicated, the term "polymer" shall also include all possible geometric configurations. Such configurations can include isotactic, syndiotactic, and atactic symmetries.

[0043] The term "polymer" refers to any two or more repeating unit / monomer units or units that are the same or different. 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 unit. The term "copolymer" refers to a polymer having two or more units that are different from one another, and includes terpolymers and the like. The term "terpolymer" refers to a polymer having three units that are different from one another. The term "different" when referring to units indicates that the units differ from one another by at least one atom or are isomerically different. Also, as used herein, the definition of polymer includes homopolymers, copolymers, and the like. By way of example, when a copolymer is said to have a "propylene" content of 10 to 30 weight percent, it is understood that the repeating unit / monomer units or simply units in the copolymer are derived from propylene in the polymerization reaction, and the units are present in an amount of 10 to 30 weight percent based on the weight of the copolymer.

[0044] The term "elastomer" shall mean any polymer that exhibits some degree of elasticity, wherein elasticity is the ability of a material that has been deformed by a force, such as by stretching, to at least partially return to its original dimensions once the force has been removed.

[0045] The term "alpha-olefin" or "alpha olefin" refers to any linear or branched compound of carbon and hydrogen having at least one double bond between an alpha carbon atom and a beta carbon atom. For the purposes of this specification and the accompanying claims, when a polymer or copolymer is referred to as including an alpha-olefin, such as a polyalpha-olefin, the alpha-olefin present in such polymer or copolymer is the polymerized form of the alpha-olefin.

[0046] A detailed description of the foamed propylene-based elastomer and methods of use thereof will now be provided. Each of the claims appended hereto defines an individual application, which is considered to include equivalents of the various elements or limitations specified in the claims, for purposes of infringement. All references to "the invention" throughout this disclosure can in some cases only refer to certain specific embodiments. In other cases, it will be appreciated that references to "the invention" will mean the subject matter claimed in one or more but not necessarily all claims. Each invention will now be described in more detail below, including specific embodiments, variations, and examples, but the invention is not limited to these embodiments, variations, or examples, which are included for illustrative purposes only when the information in this disclosure is combined with the publicly available information and technology at the time of the disclosure to enable one of ordinary skill in the art to make and use the invention.

[0047] The foamed composition can be injection molded or compression molded into a desired shape and then physically foamed by any one or more chemical or physical foaming techniques. The foamed composition can also be made by single screw compounding, twin screw compounding, kneader / banbury mixing or similar techniques. According to the embodiments provided herein, the foamed product is lighter in weight and lower in density than mechanically equivalent products made from expanded polypropylene, polystyrene or RCP and is particularly useful in footwear such as slippers or midsoles; packaging, yoga mats and other consumer products.

[0048] The foamed composition can be or can include a blend of two or more propylene-based elastomers and one or more polypropylenes. The propylene-based elastomer is a random copolymer having crystalline regions interrupted by non-crystalline regions, having ethylene or C4-C10a-olefin derived units in the range of 5-25 wt% based on the weight of the propylene-based elastomer, and optionally diene derived units, the balance of the polymer being propylene derived units. Without intending to be bound by any theory, it is believed that the non-crystalline regions can result from polypropylene segments that are not crystallizable and / or include comonomer units. Compared to highly isotactic polypropylene, the crystallinity and melting point of the propylene-based elastomer is reduced by the introduction of errors (stereodefects and regiodefects) in the propylene insertion and / or by the presence of comonomers. The copolymer contains at least 60 wt% propylene derived units, based on the weight of the propylene-based elastomer. In any embodiment, the propylene-based elastomer is a propylene-based elastomer with limited crystallinity due to adjacent isotactic propylene units and a melting point as described herein. In other embodiments, the propylene-based elastomer is generally free of any substantial intermolecular heterogeneity in tacticity and comonomer composition, and is also generally free of any substantial heterogeneity in intramolecular composition distribution.

[0049] In some embodiments, the PBE contains at least 60 weight percent propylene and from about 5 weight percent to about 30 weight percent of one or more alpha-olefin derived units, such as ethylene and / or C4-C12 alpha-olefins. In some examples, the alpha-olefin derived units or comonomers 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, or consists only of, propylene and ethylene. Some embodiments described below are discussed with reference to ethylene as the comonomer, but the described embodiments are equally applicable to PBEs having other alpha-olefin comonomers. In this regard, the copolymers can be referred to simply as PBEs with reference to ethylene as the alpha-olefin.

[0050] The comonomer can be ethylene, 1-hexene, or 1-octene, and the preferred amount is from 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 can also be from about 3 to about 35 weight percent, from about 3 to 15 weight percent, and from about 10 to 15 weight percent, based on the total weight of the propylene-based elastomer.

[0051] The propylene-based elastomer can include 3, 5, 10, or 14 weight percent to 15, 20, 22, or 25 weight percent of ethylene derived units, based on the total weight of the propylene-based elastomer. The ethylene content of the propylene-based elastomer can also be from about 3 to about 35 weight percent, from about 3 to 15 weight percent, and from 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 units derived from propylene and ethylene, i.e., the propylene-based elastomer does not contain any other comonomer in an amount that is present as an impurity in the ethylene and / or propylene feed streams typically used in the polymerization process or any other comonomer intentionally added to the polymerization process that would materially affect the heat of fusion, melting point, crystallinity, or melt flow rate of the propylene-based elastomer.

[0052] Diene comonomer units can 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 can be equal to or greater than 0 weight percent, or 0.5 weight percent, or 1 weight percent, or 1.5 weight percent and less than or equal to 5 weight percent, or 4 weight percent, or 3 weight percent, or 2 weight percent, based on the weight of the propylene-based elastomer.

[0053] The PBE can include 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% alpha-olefin derived units, where the percentage by weight is based on the total weight of propylene derived units and alpha-olefin derived units. The PBE can include at most about 30 wt%, at most about 25 wt%, at most about 22 wt%, at most about 20 wt%, at most about 19 wt%, at most about 18 wt%, or at most about 17 wt% alpha-olefin derived units, where the percentage by weight is based on the total weight of propylene derived units and alpha-olefin derived units. In some embodiments, the PBE can contain from about 5 wt% to about 30 wt%, from about 6 wt% to about 25 wt%, from about 7 wt% to about 20 wt%, from about 10 wt% to about 19 wt%, from about 12 wt% to about 18 wt%, or from about 15 wt% to about 17 wt% alpha-olefin derived units, where the percentage by weight is based on the total weight of propylene derived units and alpha-olefin derived units.

[0054] The PBE can include 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 percentage by weight is based on the total weight of propylene derived units and alpha-olefin derived units. The PBE can include at most about 95 wt%, at most about 94 wt%, at most about 93 wt%, at most about 92 wt%, at most about 91 wt%, at most about 90 wt%, at most about 88 wt%, or at most about 85 wt% propylene derived units, where the percentage by weight is based on the total weight of propylene derived units and alpha-olefin derived units.

[0055] The PBE can be characterized by a melting point (Tm), which can be determined by differential scanning calorimetry (DSC). For purposes herein, the maximum of the highest temperature peak is considered to be the melting point of the polymer. In this context, a "peak" is defined as a change in the overall slope of the DSC curve (heat flow versus temperature) from positive to negative, thus forming a maximum, without a baseline shift, where the DSC curve is plotted such that the endothermic reaction will show as a positive peak. The Tm (as determined by DSC) of the PBE can be less than 120°C, less than 115°C, less than 110°C, or less than 105°C.

[0056] PBEs can be characterized by their heat of fusion (Hf), as determined by DSC. PBEs can have a Hf of 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. PBEs can be characterized by a 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.

[0057] As used in this specification, the DSC procedure for determining Tm and Hf is as follows. The polymer is pressed in a heated press at a temperature of about 200 °C to about 230 °C, and the resulting polymer sheet is hung to cool under ambient conditions 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 this 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 that temperature for 10 minutes. The sample is then heated at 10 °C / min to a final temperature of about 200 °C. The sample is held at 200 °C for 5 minutes. A second cooling-heating cycle is then performed in which the sample is again cooled to about -30 °C to about -50 °C and held at that temperature for 10 minutes, and then heated again to a final temperature of about 200 °C at 10 °C / min. The events from both cycles are recorded. The heat output is recorded as the area under the sample melting peak, 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.

[0058] PBEs can have a triad tacticity (mm tacticity) of 75% or greater, 80% or greater, 85% or greater, 90% or greater, 92% or greater, 95% or greater, or 97% or greater, as measured by13C NMR. For example, the triad tacticity can be in the range of 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%. The triad tacticity can be determined by the method described in U.S. Patent No. 7,232,871.

[0059] The PBE can have a tacticity index m / r ranging from a lower limit of 4 or 6 to an upper limit of 8 or 10 or 12. The tacticity index is determined by 13C nuclear magnetic resonance ("NMR"), denoted herein as "m / r". The tacticity index (m / r) is calculated as defined by H. N. Cheng in Vol. 17, MACROMOLECULES, pp. 1950-1955 (1984), which is incorporated herein by reference. The designations "m" or "r" describe the stereochemistry of adjacent propylene groups, "m" indicating meso and "r" indicating racemic. An m / r ratio of 1.0 generally describes syndiotactic polymers, and an m / r ratio of 2.0 describes atactic materials.

[0060] The PBE can have a percent crystallinity of from about 0.5% to about 40%, from about 1% to about 30%, or from about 5% to about 25%, as determined according to the DSC procedure. The crystallinity can be determined by dividing the Hf of the sample by the Hf of a 100% crystalline polymer, which is assigned a value of 189 J / g for isotactic polypropylene.

[0061] The PBE can have a density of from about 0.84 g / cm3to about 0.92 g / cm3at room temperature (about 23°C), from about 0.85 g / cm3to about 0.90 g / cm3, from about 0.86 g / cm3to about 0.89 g / cm3, or from about 0.87 g / cm3to about 0.88 g / cm3, as measured according to ASTM D-1505 test method. 3 from about 0.85 g / cm3to about 0.90 g / cm3, 3 from about 0.85 g / cm3to about 0.90 g / cm3, 3 from about 0.85 g / cm3to about 0.90 g / cm3, 3 from about 0.85 g / cm3to about 0.90 g / cm3, 3 from about 0.85 g / cm3to about 0.90 g / cm3, 3 from about 0.85 g / cm3to about 0.90 g / cm3,

[0062] The PBE can have a melt index (MI) (ASTM D-1238, 2.16 kg at 190°C) of less than or equal to about 100 dg / min, less than or equal to about 50 dg / min, less than or equal to about 25 dg / min, less than or equal to about 10 dg / min, less than or equal to about 8.0 dg / min, less than or equal to about 5.0 dg / min, or less than or equal to about 3.0 dg / min.

[0063] The PBE can 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 according to ASTM D-1238 (2.16 kg weight at 230°C). The PBE can 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 can have an MFR of from about 0.5 to about 10 dg / min, from about 1.0 to about 7 dg / min, or from about 1.5 to about 5 dg / min.

[0064] The PBE can 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 a baseline. For use herein, the g' index is defined as: g' = ηb / η1, where ηb is the intrinsic viscosity of the polymer and η1 is the intrinsic viscosity of a linear polymer having the same viscosity average molecular weight (Mv) as the polymer. η1 = KMvα, K and a are measured values for the linear polymer and should be obtained on the same instrument as used for the g' index measurement.

[0065] The PBE can have a weight average molecular weight (Mw) of from about 50,000 to about 1,000,000 g / mol, or from about 75,000 to about 500,000 g / mol, from about 100,000 to about 350,000 g / mol, from about 125,000 to about 300,000 g / mol, from about 150,000 to about 275,000 g / mol, or from about 200,000 to about 250,000 g / mol, as measured by DRI.

[0066] The PBE can have a number average molecular weight (Mn) of from about 5,000 to about 500,000 g / mol, from about 10,000 to about 300,000 g / mol, from about 50,000 to about 250,000 g / mol, from about 75,000 to about 200,000 g / mol, or from about 100,000 to about 150,000 g / mol, as measured by DRI.

[0067] 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, about 200,000 to about 375,000 g / mol, or about 250,000 to about 350,000 g / mol.

[0068] 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, about 200,000 to about 375,000 g / mol, or about 250,000 to about 350,000 g / mol.

[0069] Optionally, the PBE can further include one or more dienes. The term "diene" is defined as a hydrocarbon compound having two sites of unsaturation, such as a compound having two double bonds attached to carbon atoms. The term "diene" as used herein broadly refers to a diene monomer prior to polymerization (e.g., to form part of a polymerization medium), or a diene monomer after polymerization has begun (also referred to as a diene monomer unit or diene-derived unit), depending on the context. In some embodiments, the diene can be selected from the group consisting of 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, vinyl norbornene (VNB), dicyclopentadiene (DCPD), and combinations thereof. In embodiments where the PBE composition contains a diene, the diene can 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%, from about 0.5 wt% to about 1.5 wt% diene-derived units, where the percentage by weight is based on the total weight of propylene-derived units, alpha-olefin-derived units, and diene-derived units.

[0070] Optionally, the PBE can be grafted (e.g., "functionalized") with one or more grafting monomers. As used herein, the term "grafted" means that the grafting monomer is covalently bonded to the polymer chains of the PBE. The grafting monomer can be or include at least one ethylenically unsaturated carboxylic acid or acid derivative, such as an anhydride, ester, salt, amide, imide, or acrylate. Illustrative 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-octahydro naphthalene-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, methyl nadic anhydride, himic anhydride, methyl himic anhydride, and 5-methylbicyclo(2.2.1 )heptene-2,3-dicarboxylic anhydride. Other suitable grafting monomers include methyl acrylate and higher alkyl acrylates, methyl methacrylate and higher alkyl methacrylates, acrylic acid, methacrylic acid, hydroxymethyl methacrylate, hydroxyethyl methacrylate and higher hydroxyalkyl methacrylates, and glycidyl methacrylate. Maleic anhydride is a grafting monomer. In embodiments, the grafting monomer can be or include maleic anhydride, and the concentration of maleic anhydride in the grafted polymer is in the range of about 1 wt% to about 6 wt%, at least about 0.5 wt%, or at least about 1.5 wt%.

[0071] In some embodiments, the PBE is a reactor blend polymer. That is, the PBE is a reactor blend of the first polymer component and the 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.

[0072] In embodiments where the PBE is a reactor blended polymer, the first polymer component can have an alpha-olefin content of greater than 5 wt% alpha-olefin, greater than 7 wt% alpha-olefin, greater than 10 wt% alpha-olefin, greater than 12 wt% alpha-olefin, greater than 15 wt% alpha-olefin, or greater than 17 wt% alpha-olefin, where the percentage by weight is based on the total weight of propylene-derived units and alpha-olefin-derived units of the first polymer component. The first polymer component can have an alpha-olefin content of less than 30 wt% alpha-olefin, less than 27 wt% alpha-olefin, less than 25 wt% alpha-olefin, less than 22 wt% alpha-olefin, less than 20 wt% alpha-olefin, or less than 19 wt% alpha-olefin, where the percentage by weight is based on the total weight of propylene-derived units and alpha-olefin-derived units of the first polymer component. In some embodiments, the first polymer component can have an alpha-olefin content of 5 wt% to 30 wt% alpha-olefin, 7 wt% to 27 wt% alpha-olefin, 10 wt% to 25 wt% alpha-olefin, 12 wt% to 22 wt% alpha-olefin, 15 wt% to 20 wt% alpha-olefin, or 17 wt% to 19 wt% alpha-olefin. In some examples, the first polymer component contains or comprises propylene and ethylene, and in some embodiments the first polymer component consists only of propylene and ethylene-derived units.

[0073] In embodiments where the PBE is a reactor blended polymer, the second polymer component can have an alpha-olefin content of greater than 1.0 wt% alpha-olefin, greater than 1.5 wt% alpha-olefin, greater than 2.0 wt% alpha-olefin, greater than 2.5 wt% alpha-olefin, greater than 2.75 wt% alpha-olefin, or greater than 3.0 wt% alpha-olefin, where the percentage by weight is based on the total weight of propylene-derived units and alpha-olefin-derived units of the second polymer component. The second polymer component can have an alpha-olefin content of less than 10 wt% alpha-olefin, less than 9 wt% alpha-olefin, less than 8 wt% alpha-olefin, less than 7 wt% alpha-olefin, less than 6 wt% alpha-olefin, or less than 5 wt% alpha-olefin, where the percentage by weight is based on the total weight of propylene-derived units and alpha-olefin-derived units of the second polymer component. In some embodiments, the second polymer component can have an alpha-olefin content of 1.0 wt% to 10 wt% alpha-olefin, or 1.5 wt% to 9 wt% alpha-olefin, or 2.0 wt% to 8 wt% alpha-olefin, or 2.5 wt% to 7 wt% alpha-olefin, or 2.75 wt% to 6 wt% alpha-olefin, or 3 wt% to 5 wt% alpha-olefin. In some examples, the second polymer component contains propylene and ethylene, and in some embodiments the first polymer component consists only of propylene and ethylene-derived units.

[0074] In certain embodiments, the PBE contains propylene-derived units and from about 5 wt% to about 30 wt% of alpha-olefin-derived units and has a melting temperature of less than 120°C and a heat of fusion of less than 75 J / g.

[0075] In certain embodiments, the PBE contains propylene-derived units and from about 15 wt% to about 30 wt% 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.

[0076] In embodiments where the PBE is a reactor blend polymer, the PBE can contain from 1 wt% to 25 wt% of the second polymer component, from 3 wt% to 20 wt% of the second polymer component, from 5 wt% to 18 wt% of the second polymer component, from 7 wt% to 15 wt% of the second polymer component, or from 8 wt% to 12 wt% of the second polymer component, based on the weight of the PBE. The PBE can contain from 75 wt% to 99 wt% of the first polymer component, from 80 wt% to 97 wt% of the first polymer component, from 85 wt% to 93 wt% of the first polymer component, or from 82 wt% to 92 wt% of the first polymer component, based on the weight of the PBE.

[0077] In one or more embodiments, the PBE contains a reactor blend of a first polymer component and a second polymer component. The first polymer component contains propylene and alpha-olefins and has an alpha-olefin content of greater than 5 wt% to less than 30 wt% of alpha-olefins, based on the total weight of propylene-derived and alpha-olefin-derived units of the first polymer component. The second polymer component contains propylene and alpha-olefins and has an alpha-olefin content of greater than 1 wt% to less than 10 wt% of alpha-olefins, based on the total weight of propylene-derived and alpha-olefin-derived units of the second polymer component. In one or more examples, the first polymer component has an alpha-olefin content of from about 10 wt% to about 25 wt% of alpha-olefins, based on the total weight of propylene-derived and alpha-olefin-derived units of the first polymer component. The second polymer component has an alpha-olefin content of greater than 2 wt% to less than 8 wt% of alpha-olefins, based on the total weight of propylene-derived and alpha-olefin-derived units of the second polymer component. In other examples, the PBE contains from about 1 wt% to about 25 wt% of the second polymer component and from about 75 wt% to about 99 wt% of the first polymer component, based on the weight of the PBE.

[0078] PBEs can be prepared by any suitable means as known in the art. PBEs can be prepared using homogeneous conditions, for example, continuous solution polymerization processes, using metallocene catalysts. 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 effluent from the first and second reactors are combined and blended to form a single effluent from which the final PBE is isolated. Exemplary methods of preparing PBEs can be found in U.S. Patent Nos. 6,881,800; 7,803,876; 8,013,069; and 8,026,323; and PCT Publications WO 2011 / 087729; WO 2011 / 087730; and WO 2011 / 087731.

[0079] Polypropylene

[0080] The terms "polypropylene", "propylene polymer", and "propylene-based polymer" mean a polymer or copolymer comprising 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, even more preferably at least 95 mol% propylene units, or 100 mol% propylene units (in the case of a homopolymer)).

[0081] The polypropylene can be or can include homopolypropylene ("hPP"), isotactic polypropylene, highly isotactic polypropylene, syndiotactic polypropylene, and copolymers of propylene or mixtures thereof. The product including one or more propylene monomers polymerized with one or more additional monomers can be more commonly referred to as a random copolymer (RCP) or an impact copolymer (ICP). Impact copolymers can also be referred to in the art as heterophasic copolymers. "Propylene-based" as used herein means containing any polymer that individually contains propylene or contains propylene along with one or more comonomers, where propylene is the major component (e.g., greater than 50 wt% propylene).

[0082] The term "random polypropylene" as used herein broadly means a single phase copolymer of propylene having up to 9 wt%, preferably 2 wt% to 8 wt%, of alpha-olefin comonomer. Preferred alpha-olefin comonomers have 2 carbon atoms, or 4 to 12 carbon atoms. Preferably, the alpha-olefin comonomer is ethylene.

[0083] "Reactor grade" as used herein means a polymer that has not been subjected to chemical or mechanical treatment or blending in an attempt to alter the average molecular weight, molecular weight distribution, or viscosity of the polymer after polymerization. Specifically excluded from those described as reactor grade are those that have been visbroken or otherwise treated or coated with peroxide or other degradation aids. However, for the purposes of the present disclosure, reactor grade polymers include those that are reactor blends.

[0084] The weight average molecular weight (Mw) of the polypropylene can be between 50,000 to 3,000,000 g / mol, or between 90,000 to 500,000 g / mol, with a molecular weight distribution (MWD, Mw / Mn) ranging from 1.5 to 2.5 or 3.0 or 4.0 or 5.0 or 20.0. The polypropylene can have a MFR (2.16 kg / 230°C) ranging from 10 or 15 or 18 to 30 or 35 or 40 or 50 dg / min.

[0085] Blowing agent

[0086] The blowing agent can include, but is not limited to, decomposable chemical blowing agents and physical blowing agents. Physical blowing can include a gas, such as air, nitrogen, carbon dioxide, etc., that can be injected into the composition during an injection molding process. Chemical blowing agents decompose at elevated temperatures to form a gas or vapor to blow the polymer into a foamed form. Suitable chemical blowing agents include, but are not limited to, organic blowing agents such as 4,4'-oxybisbenzenesulfonylhydrazide; azodicarbonamide; azobisformamide; azobisdimethylvaleronitrile; diazaminobenzene; N,N-dimethyl-N,N-dinitrosophtalimide; N,N-dinitrosopentamethylenetetramine; benzenesulfonylhydrazide; benzene-1,3-disulfonylhydrazide; diphenyl sulfone-3-3, disulfonylhydrazide; p-toluenesulfonylsemicarbazide; barium azodicarboxylate; butylcarbazonitrile; nitrosourea; trihydrazinotriazine; phenyl-methyl-uranthan; p-sulfonylhydrazide; peroxides; and inorganic blowing agents such as ammonium bicarbonate and sodium bicarbonate.

[0087] The blowing agent can be used in an amount of less than or equal to about 25 wt%, less than or equal to about 20 wt%, less than or equal to about 15 wt%, less than or equal to about 10 wt%, or less than or equal to about 6 wt%, relative to the total amount of the polymer to be foamed. In some embodiments, the blowing agent can be used in an amount of about 0.1 wt% to 25 wt%, about 0.2 wt% to 20 wt%, about 0.3 wt% to 15 wt%, about 0.4 wt% to 10 wt%, or about 0.5 wt% to 6 wt%, relative to the total amount of the PBE and copolymer to be foamed.

[0088] The foamed composition can be prepared or formed by any of the available independent molding or continuous extrusion means known in the art for shaping and molding polyolefins, including: single screw compounding, twin screw compounding, kneader / banbury mixing, sheet extrusion, profile extrusion or co-extrusion, compression molding, injection molding, co-injection molding, gas assisted injection molding, transfer molding, foam molding, transfer molding, vacuum molding, lamination, calendering, or other processing forms.

[0089] In an embodiment, the composition can be extruded into pellets, or a sheet-like shape, etc. by an extruder (molding step) and the extruded composition can be heated and foamed (foaming step). During the foaming step, the composition can be inserted into a pre-heated chamber or autoclave at a temperature, for example, in the range of 40 to 200 °C, or 60 to 160 °C, and then heated at a temperature of no greater than 450 °C, or in the range of 100 to 400 °C, or 120 to 350 °C, for a time period, for example, 1 to 80 minutes, or 2 to 50 minutes, or 1 minute to 10 hours, or about 0.5 hour - 8 hours, or about 1 hour to about 6 hours, or 2 hours to 6 hours. Alternatively, using a press, the prepared composition can be molded into a sheet-like shape while being heated, thereby foaming at the opening of the press (foaming step).

[0090] Figure 1 An example apparatus 100 for forming foamed beads from expanded pellets is illustrated. The pellets and water are loaded into a high pressure stainless steel vessel 102 equipped with a heating system 104. In an embodiment, the water inside the vessel 102 acts as a heat transfer medium. The pellets and water are stirred by a stirrer 106. A gas, for example CO2, is introduced into the vessel via an outlet 108 to reach a desired pressure inside the vessel. The vessel 102 is then heated by the heater 104 to a target temperature. At the target temperature, the vessel 102 is kept for some time to allow the gas to saturate. Next, the vessel 102 is depressurized by opening a shut-off valve 110 and the foamed beads are obtained in a collection device 112.

[0091] Other examples of molding and foaming processes are disclosed in U.S. Publication No. 20200181350.

[0092] Due to its relatively low molecular weight and thermoplastic properties, the propylene-based elastomer in the compositions described herein reduces the density of the foamed product made therefrom by facilitating gas expansion and creating larger cells during the foaming step.

[0093] The compositions described herein can include at least 20 weight percent of one or more PBEs, based on the total weight of the composition. The compositions can also include at least 22 weight, at least 25 weight percent, at least 30 weight percent, at least 40 weight percent, or at least 50 weight percent of one or more PBEs, based on the total weight of the composition. The compositions can also contain one or more PBEs in an amount ranging from a lower limit of about 20 weight percent, 25 weight percent, or 30 weight percent to an upper limit of about 75 weight percent, 85 weight percent, or 95 weight percent, with the balance being one or more polypropylenes.

[0094] In some embodiments, the compositions include one or more propylene-based elastomers in an amount of at least 20 weight percent, based on the total weight of the composition, and provide a foamed product made therefrom having a density (ASTM D792-08, 23°C) that is at least 5 percent, at least 7 percent, at least 10 percent, or at least 12 percent lower than the density of a comparative foamed product made from polystyrene, polypropylene, or RCP.

[0095] The compositions can have a flexural modulus (ISO 178) of at least 200 MPa. The flexural modulus can 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 can also range from a lower limit of about 300, 500, or 600 to an upper limit of about 800, 1000, or 1500 MPa. The compositions can have a notched Izod impact (ISO 180) of at least 5 KJ / m2at 23°C, an ISO 527 based tensile stress at yield of at least 10 MPa, and a tensile strain at yield of at least 4 percent. 2

[0096] The compositions can have a Vicat softening point (ASTM D1525-07) 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 can also range from a lower limit of about 45, 50, 60, 80, 100, or 115 to an upper limit of about 130, 150, or 170°C.

[0097] The compositions can also have any combination of two or more of the foregoing densities, flexural modulus (ISO 178), Vicat softening point (ASTM D 1525-07), notched Izod impact (ISO 180), and ISO 527 based tensile stress at yield and tensile strain at yield.

[0098] ​The foamed beadstock produced using the compositions described herein can 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 can be between 10 microns to 10 mm, preferably 100 microns - 5 mm.

[0099] The expanded foamed beadstock ("EFB") made from the compositions provided herein can have a density of 0.140 g / cm 3 or less. The EFB preferably has a density of less than 0.135, 0.130, 0.120, or 0.110 g / cm 3 . The EFB can have a density in a range from a lower limit of about 0.03, 0.05, 0.07, or 0.08 g / cm 3 to an upper limit of about 0.11, 012, 0.10, or 0.14 g / cm 3 .

[0100] In the above detailed description, the specific embodiments of the disclosure are described in connection with its preferred embodiments. However, to the extent that the above description refers to particular embodiments or particular uses of the disclosure, such description is for illustrative purposes only and is merely the best of the presenter's knowledge at the time of the application. Therefore, the disclosure is not limited to the specific embodiments described above, but rather includes all alternatives, modifications and equivalents falling within the true scope of the appended claims. Various modifications and changes can be made to the disclosed embodiments by those skilled in the art which follow from the principles of the disclosure and such modifications and changes are intended to fall within the scope of this application and the appended claims. Examples

[0101] The embodiments discussed and described herein can be further described using the following examples. While the following examples refer to specific embodiments, they are not to be considered limiting in any specific respect.

[0102] Example 1

[0103] Injection molded two plaque samples and then foamed to test the physical properties of the unblended polymers. Sample No. 1 was made from a first propylene-based copolymer (PBE1) having a 230°C / 2.16 kg down melt index of 3 g / 10 min and a density of 0.862 g / cm 3 . Sample No. 2 was made from a second propylene-based copolymer (PBE2) having a 230°C / 2.16 kg down melt index of 8 g / 10 min and a density of 0.879 g / cm 3 . Sample No. 2 was made from a second propylene-based copolymer (PBE2) having a 230°C / 2.16 kg down melt index of 8 g / 10 min and a density of 0.879 g / cm

[0104] The polymer was injection molded into plaques and inserted into a preheated mold of a compression foaming machine from Wuxi Jinhe Technology Co., Ltd. Table 1 summarizes the processing parameters and conditions.

[0105] Table 1: Processing parameters and conditions

[0106]

[0107] Figure 2A SEM of sheet No. 1 showing foaming, and Figure 2B is Figure 2A Magnified view of the SEM described in .

[0108] Example 2

[0109] Expanded foam beads ("EFB") were also prepared. The polymer components used for these EFBs were 230°C / 2.16 kg having a melt index of 8 g / 10 min and a viscosity of 0.879 g / cm 3 A second propylene-based copolymer (PBE2) of a density of 8 g / 10 min was obtained from ExxonMobil; having a melt index at 230°C / 2.16 kg of 8 g / 10 min and a viscosity of 0.889 g / cm 3 A third propylene-based copolymer (PBE3) having a density of 1000 nm, obtained from ExxonMobil; a polypropylene homopolymer (hPP, trade name PP T30S) having a melt index at 230°C / 2.16 kg of 3 g / 10 min, obtained from Sinopec; and a polypropylene homopolymer having a melt index at 230°C / 2.16 kg of 7 g / 10 min and a melt index of 0.90 g / cm 3 A random copolymer (RCP, trade name W331) with a density of 1.5 wt% was obtained from TPC. Table 2 below reports the flexural modulus (ISO 178) and Vicat softening point (ASTM D1525-07) of the EFB formulations and each polymer formulation before foaming. Table 3 reports the notched Izod impact (ISO 180), tensile stress at yield based on ISO 527, and tensile strain at yield for each polymer formulation.

[0110] Table 2: Formulation

[0111]

[0112] Table 3: Test results of flexural modulus and Vicat softening point

[0113]

[0114]

[0115] Figure 3 、 4DSC curves (based on ASTM D 3418) for EFB-003, EFB-006, and EFB-013 samples are shown in Figures 5. From the curves, the EFB-003 and EFB-006 samples both have a melting peak at about 165 °C, and the EFB-013 sample has a melting peak at about 150 °C. The samples EFB-003, EFB-006, and EFB-013 were selected to be tested in industrial expanded foam bead tests and steam molding tests. Each of EFB-003, EFB-006, and EFB-013 was first compounded using a twin-screw extruder. The compounded material was then pelletized into micropellets having a width of about 1 mm and a length of about 1.2 mm. The micropellets of each of EFB-003, EFB-006, and EFB-013 were then foamed into beads using an autoclave. Carbon dioxide was used as the blowing agent.

[0116] Table 4: Characteristics of selected expanded foam beads

[0117]

[0118] The foamed beads were then molded using steam at different pressures. Figure 6 Photographs of the EFB-003 and EFB-006 samples after steam molding at 1.6 bar steam pressure are shown. Note that the EFB-003 sample has a better surface compared to the EFB-006 sample. This shows that EFB-003 is more suitable for molding at this 1.6 bar steam pressure. Figure 7 Photographs of the EFB-013 sample after steam molding at 1.4 bar are shown. In addition, the significant reduction in steam pressure compared to the normal 2-3 bar required for conventional ethylene-propylene copolymer products provides significant cost savings.

[0119] The mechanical properties of the steam molded samples of EFB-003 and EFB-013 at 1.8 bar steam pressure were tested. The results of the compression strength (based on GB / T 8813) and tensile properties (based on GB / T 6344) are summarized in Tables 5 and 6.

[0120] Table 5: Compression strength of steam molded samples

[0121]

[0122] Table 6: Tensile properties of steam molded samples

[0123]

[0124] Example 3

[0125] EFBs including a single polymer component were also prepared. The polymer component used for these EFBs was PBE3. First, PBE3 was drawn into filaments by an extruder and pelletized. The pellets had a diameter of about 1 mm. Then, the PBE3 pellets were foamed. Water, PBE3 pellets, and an isolation 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 was started. 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 pellets were removed from the foaming kettle with a gas stream and formed into a foamed bead material. The foamed bead material was dried on a fluidized bed dryer at 50-80°C for 1 hour and a foamed bead material product was obtained. The foamed density of the bead material was 0.074 g / cm3, and the volume expansion ratio of the foam was about 13.5 times. The foam pellets were smooth, plump, and uniform in size. 3 8

[0126] The melting point of the PBE3 EFB was determined by DSC performed on a Perkine-Elmer DSC-7 instrument using a heating rate of 20°C / min over a temperature range of 25-150°C. The measurements were performed under a N2atmosphere. The mass of the sample was 5-10 mg. As can be seen from the DSC melting curve in Figure 8 , there is a clear multi-stage melting behavior. The melting points are 80°C, 104°C, and 120°C, respectively, which is beneficial for steam molding of the foam. The PBE3 EFB was fractured, and the fractured surface was observed under a PHILLIPS XL30 ESEM FEG field emission scanning electron microscope. As can be seen in Figure 9 , the pores are uniform. The pore size is about 36.7 μm, and the pore density is 3.3 x 10 8 .

[0127] The PBE3 EFB was then molded into a plaque. The PBE3 EFB was first pre-pressed in a pre-press tank for 6 h and 0.06 MPa, and then sent to the hopper of the molding machine for steam chamber molding. The molding machine was operated according to a fixed program to perform a cycle of the steam chamber molding process. First, the mold was closed, the foam bead material was flowed into the mold with air, steam was passed through the mold from the left side, steam was passed through the mold from the right side, steam was added from both sides simultaneously, the sample was cooled with water, the mold was opened automatically, and finally the sample was ejected automatically. The steam chamber molding pressure was set to 0.1-0.12 MPa, the time for each addition stage was 2-4 s, and the time for water cooling was 150 s.

[0128] Under such conditions, a good steam chamber molded product was obtained, as shown in Figure 10A . The product was uniform, showing a uniform surface property. As Figure 10BThe bonding between the foamed beads was very good. The foamed beads were very well fused together without showing any apparent boundaries. Therefore, for steam consumption, the PBE3 foams showed lower steam chest molding temperature and less molding time compared to EPS foams at molding conditions close to those of the EPS foams.

[0129] The mechanical properties of the steam molded product were performed following the method described in Chinese Standard GB 8813. The compressive strength was 0.138 ± 0.014 MPa at 25%, 0.235 ± 0.022 MPa at 50% and 0.552 ± 0.051 MPa at 75%. The tensile strength was 52.3 ± 4.2 MPa and the tensile elongation at break was 88 ± 7%.

[0130] When used alone to form EFB, the PBE3 polymer showed a broad T m range and good foaming ability. Since the chain structure of PBE3 and PP are similar, PBE3 showed good compatibility with PP. This indicates that PBE3 can shift the T m of the foamed beads to a lower temperature range compared to PP alone. Therefore, PP-PBE3 foamed beads can achieve good fusion at low T / low steam chest pressure, resulting in significant energy savings and equipment cost savings.

[0131] Example 4

[0132] Expanded foamed beads were produced using PBE2 and PBE3 pellets. PBE2 and PBE3 pellets and water were each separately charged into a high pressure stainless steel vessel equipped with a heating system. Water was used as heat transfer medium. At an appropriate agitation speed of 200 r / min, C02was charged into the vessel to reach the desired pressure. The chamber was then heated to the target temperature. At the target temperature, the chamber was kept for some time for C02saturation. Thereafter, depressurization was performed by opening the shut-off valve and the bead foams were obtained in a collection device.

[0133] DSC was used to study the thermal behavior of the foamed PBE beads. As for Figure 11 PBE3 shown in FIG. 11, two distinct endothermic peaks were observed in the first heating curve (line 1101). The lower peak at 108°C was relatively broader than the higher peak at 121°C. In the second heating curve (line 1102), which provides virgin state polymer information without thermal history, only one peak at 107°C was found. The difference between the first and second melting curves indicates that two crystal structures with different stabilities were formed during the foaming process. This result indicates that the goal of the stream pressing method can be targeted at the lower melting peak, so that the foamed beads can partially melt at the surface and then fuse with each other while maintaining their original shape.

[0134] Similarly, the same phenomenon was observed in the DSC curve of PBE2 in Figure 12 For the first heating curve (line 1201), there were a lower peak around 107°C and a higher peak at 116°C. Relatively, the melting point of the original polymer was at 107°C according to the second heating curve (line 1202). The results showed that both foamed PBE2 and PBE3 could form two melting peaks, which was important for their subsequent stream compression molding process.

[0135] A simple experiment was designed to simulate the molding process, as shown in Figure 13 The foamed PBE beads were completely filled into a stainless steel jar with a screw cap. After the cap was tightly screwed, the foamed beads were in a compressed state. Then, the jar was placed in an oven at a certain temperature for a period of time and then removed from the oven for cooling. The molded beads were then removed from the jar to check the fusion quality and appearance. PBE3 was kept in an oven at 110°C for 7 min. PBE2 was kept in an oven at 95°C for 6 min.

[0136] This example shows that for PBE2 and PBE3, the foamed pellets exhibit a double-peak melting behavior, which can be used to define a target temperature window for compression molding, within which the foam bead surface will stick, but the foam bead structure is preserved.

[0137] All patents and patent applications, test procedures (such as ASTM methods, UL methods, and the like), and other documents cited in this disclosure are fully incorporated by reference to the extent that they provide exemplary, procedural or other appropriate disclosure.

[0138] Certain embodiments and features have been described using a set of upper numerical limits and a set of lower numerical limits. It should be appreciated that ranges formed by any combination of these upper and lower limits are also contemplated unless otherwise indicated. Certain lower limits, upper limits, and ranges appear in one or more of the claims. All numerical values are the indicated values "about" or "approximately," meaning that the value accounts for experimental error, machine tolerances, and other deviations that would be expected by one of ordinary skill in the art.

[0139] The foregoing generally outlines features of the embodiments so that those skilled in the art can better understand the present disclosure. Those skilled in the art should appreciate that they can readily use the present disclosure as a basis for designing or modifying other processes and / or structures for carrying out the same purposes and / or achieving the same advantages of the embodiments disclosed herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure. The scope of the present disclosure is defined by the appended claims.

[0140] Various terms are defined above. To the extent a term used in a claim is not defined above, such term is given its broadest definition everybody skilled in the relevant art has given to such term as reflected in at least one printed publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are fully incorporated by reference to the extent such disclosure is not contradictory to this application.

[0141] While the foregoing is directed to embodiments of the present application, other and further embodiments of the application can be devised without departing from the basic scope thereof, and the scope of the application is determined by the claims that follow.

Claims

1. A foamable polymer composition comprising: (a) at least 5 wt% based on the total weight of the composition of at least one propylene-based elastomer, the propylene-based elastomer comprising propylene and from about 15 wt% to about 30 wt% of one or more α-olefin-derived units, 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 from about 3 J / g to about 75 J / g, as determined by DSC; (b) less than 95 weight percent, based on the total weight of the composition, of at least one polypropylene; and (c) a blowing agent; wherein the polymer blend has a viscosity of at least 0.80 g / cm prior to combining with the blowing agent. 3 The density of the foamed article is 0.2 g / cm 3 or smaller density.

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

3. The foamable polymer composition of claim 1 , wherein the at least one propylene-based elastomer comprises at least 20 weight percent of the foamable polymer composition.

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

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

6. The foamable polymer composition of claim 1 wherein the polypropylene comprises at least 70 wt% propylene derived units.

7. Foamed beads comprising at least 80 wt% of a propylene-based elastomer, based on the total weight of the foamed beads, the propylene-based elastomer comprising propylene and from about 15 wt% to about 30 wt% of one or more α-olefin-derived units, 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 from about 3 J / g to about 75 J / g, as determined by DSC.

8. The foamed beads according to claim 7, further comprising a foaming agent.

9. The expanded beads of claim 7, wherein the expanded beads have a melting temperature of less than 111°C.

10. The expanded beads according to claim 7, wherein the expanded beads have a melting temperature of 100-111°C.

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

12. A method for 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 so that the blowing agent expands within the mixture to produce foam; and (c) Obtained a 0.11 g / cm 3 or less, wherein the molten polymer composition comprises the composition of claim 1.

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

14. A method for producing a foamed beaded article, comprising: introducing a plurality of foamed beads into a mold; Increase the pressure in the mold to an elevated pressure of 0.1-0.5 MPa; heating the foamed beads in the mold to an elevated temperature of 35-125°C; maintaining the elevated pressure and elevated temperature for a compression time to form a foamed bead article; and De-mould the product.

15. A method according to claim 14, wherein the foamed beads are heated to a temperature of 90-115°C.

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

17. The method of claim 14, wherein the elevated pressure is 0.1-0.12 MPa.

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

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