Propylene-based blend composition

Abstract

Higher M W The main polymer fraction has a lower M W A propylene-based elastomer composition comprising a major polymer fraction having a Mw of about 100,000 to about 300,000 and a melt flow rate according to ASTM D1238 of about 0.1 g / 10 min to about 70.0 g / 10 min, and a minor polymer fraction having a Mw of about 5,000 to about 60,000 and a Brookfield viscosity according to ASTM D-3236 (190°C) of about 500 cP to about 50,000 cP, wherein the amount of at least one other polyolefin comonomer in the minor polymer fraction is at least 7 wt% less than the amount of at least one other polyolefin comonomer in the major polymer fraction.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the benefit of U.S. Provisional Application No. 63 / 290,719, filed on 17 December 2021, which is incorporated herein by reference in its entirety.

[0002] field Embodiments of the present invention generally relate to polymer blend compositions. More specifically, the embodiments relate to higher M W A main polymer fraction having a lower M W The present invention relates to a propylene-based elastomer composition containing a blend with a small polymer fraction having the same, and to a method for producing the same. [Background technology]

[0003] background Propylene elastomers have been developed and are in high demand due to their high elasticity, flexibility, toughness, transparency, and processability. These elastomers have a wide range of applications, including blown and cast films, injection molded containers and other articles, nonwoven fabrics, and hot-melt adhesives. Both high-viscosity and low-viscosity propylene elastomers are manufactured. Unfortunately, conventional propylene elastomers often fail to achieve a good balance of elasticity, stiffness, and flow properties. As a result, customers of propylene elastomers often use multiple propylene elastomer products in pellet form in their production facilities to achieve the desired elasticity, stiffness, and flowability required for end-use products such as carpet backing sheets. The handling costs of using so many products in combination can be very high due to the need for multiple conveyor systems. Furthermore, mixing different propylene elastomer products can lead to pellet aggregation and, consequently, flow problems throughout the production facility.

[0004] One type of catalyst system that can be used in the production of propylene-based elastomers is a metallocene-based catalyst system. A metallocene catalyst is a homogeneous single-site catalyst that includes an organometallic coordination compound in which one or two cyclopentadienyl rings or substituted cyclopentadienyl rings are π-bonded to a central transition metal atom. Metallocene catalysts typically produce propylene-based elastomers having a narrow molecular weight distribution and a uniform distribution of comonomers between molecules. Polymers having a narrow molecular weight distribution and a uniform comonomer distribution can be advantageous for certain end uses, but this type of polymer may not be desirable for other uses. For example, the stability of processing operations such as blow films and blow molding is lower for polymers having a narrow molecular weight distribution compared to polymers having a broad molecular weight distribution, resulting in a decrease in productivity. Also, polymers having a uniform comonomer distribution may have undesirable melt processing properties compared to polymers having a broad comonomer distribution (sometimes referred to as a conventional composition distribution) across the molecular chains. Therefore, there is a need for a method to produce propylene-based elastomers having a combination of high elastic and rigid properties at low cost without worrying about pellet agglomeration problems. Also, it would be advantageous to have the ability to produce propylene-based elastomers having a broad molecular weight distribution and a broad comonomer distribution. SUMMARY OF THE INVENTION

[0005] Abstract Higher M W A propylene-based elastomer composition is provided that includes a blend of a major polymer fraction having and a minor polymer fraction having a lower M W The propylene-based composition can be used to produce various end-use products such as carpet backing sheets and hot melt adhesives (HMAs). In one or more embodiments, the polymer blend composition is a main polymer fraction comprising propylene-derived units and units derived from at least one other comonomer, the main polymer fraction having a Mw of about 100,000 to about 300,000 and a melt flow rate (MFR) of about 0.1 g / 10 min to about 70.0 g / 10 min according to ASTM D1238, and a minor polymer fraction comprising propylene-derived units and units derived from at least one other comonomer, the minor polymer fraction having a Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 50,000 cP according to ASTM D-3236 (190° C), wherein the amount of at least one other polyolefin comonomer in the minor polymer fraction is at least 7 wt% less than the amount of at least one other polyolefin comonomer in the main polymer fraction.

[0006] In one or more embodiments, the process for producing the polymer blend composition comprises combining a main polymer fraction comprising propylene-derived units and units derived from at least one other comonomer with a minor polymer fraction comprising propylene-derived units and units derived from at least one other comonomer to form the polymer blend composition, the main polymer fraction having a Mw of about 100,000 to about 300,000 and a MFR of about 0.1 g / 10 min to about 70.0 g / 10 min according to ASTM D1238, and the minor polymer fraction having a Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 5,000 cP according to ASTM D-3236 (190° C), wherein the amount of at least one other comonomer-derived unit in the minor polymer fraction is at least 7 wt% less than the amount of at least one other comonomer-derived unit in the main polymer fraction.

[0007] In one or more embodiments, the hot melt adhesive composition comprises a polymer blend composition comprising a main polymer fraction comprising propylene-derived units and at least one other comonomer-derived units, having a Mw of about 100,000 to about 300,000 and a melt flow rate of about 0.1 g / 10 min to about 70.0 g / 10 min according to ASTM D1238, and a minor polymer fraction comprising propylene-derived units and at least one other comonomer-derived units, having a Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 50,000 cP according to ASTM D-3236 (190°C), wherein the amount of at least one other polyolefin comonomer in the minor polymer fraction is at least 7 wt% less than the amount of at least one other polyolefin comonomer in the main polymer fraction.

[0008] To allow for a more detailed understanding of the above-mentioned features of the present invention, a more specific description of the invention, which has been briefly summarized above, can be given with reference to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings merely illustrate typical embodiments of the present invention, and since the present invention may recognize other equally effective embodiments, the accompanying drawings should not be considered as limiting the scope of the invention. [Brief explanation of the drawing]

[0009] [Figure 1] A process flow diagram for a process to produce a polymer blend composition according to one or more embodiments provided herein is shown. [Figure 2a] This graph shows the molecular weight distribution and the comonomer distribution over the molecular weight of the polymer for a propylene-ethylene blend composition according to one or more embodiments provided herein. [Figure 2b] This graph shows the bimodal molecular weight distribution and cumulative molecular weight distribution of a propylene-ethylene blend composition according to one or more embodiments provided herein. [Modes for carrying out the invention]

[0010] Detailed explanation It should be understood that the following disclosure describes several exemplary embodiments for performing various features, structures, and / or functions of the present invention. The following describes exemplary embodiments of components, arrangements, and configurations to simplify the disclosure. However, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Furthermore, the disclosure may repeat reference numbers and / or reference letters across various exemplary embodiments and the drawings provided herein. This repetition is for simplification and clarity and does not in itself indicate any relationship between the various exemplary embodiments and / or configurations considered in the drawings. Furthermore, the exemplary embodiments described below can be used in any combination; that is, any element of one exemplary embodiment can be used in any other exemplary embodiment without departing the scope of the disclosure.

[0011] Specific embodiments and features are described using a series of upper and lower numerical limits. Unless otherwise indicated, it should be understood that the range is intended to include any combination of two values, for example, any combination of any lower and upper limit, any combination of any two lower limits, and / or any combination of any two upper limits. Specific lower limits, upper limits, and ranges appear in one or more of the following claims. All numerical values ​​are indicated as "about" or "approximately," taking into account experimental errors and variations that a person skilled in the art would expect. Furthermore, certain terms are used to represent specific components throughout the following description and claims. As will be apparent to those skilled in the art, various entities may refer to the same component by different names, and similarly, the naming conventions for the elements described herein are not intended to limit the scope of the invention unless specifically defined herein. Moreover, the naming conventions used herein are not intended to distinguish between components that have different names but the same function.

[0012] In the following discussion and claims, the terms “including” and “comprising” are used in an unrestricted manner and should therefore be interpreted as “including, but not limited to.” The expression “consisting essentially of” means that the described composition and / or claimed composition does not contain any other components that substantially alter its properties by more than 5%, and in either case does not contain any other components up to a level greater than 3% by mass. The term "or" is intended to encompass both exclusive and inclusive cases; that is, "A or B" is to be considered synonymous with "at least one of A and B" unless expressly specified herein. The indefinite articles "a" and "an" refer to both the singular (i.e., "one") and the plural (i.e., one or more) unless the context makes it clear that they should be interpreted in the other way. For example, embodiments using "an olefin" include embodiments using one, two, or three or more olefins, unless otherwise specified or the context clearly indicates the use of only one type of olefin. The terms "wt%" mean mass percentage, "vol%" mean volume percentage, "mol%" mean mole percentage, and "ppm" mean parts per million. "ppm wt" and "wppm" are used interchangeably to mean parts per million by mass. All concentrations in this specification are expressed based on the total amount of the composition in question, unless otherwise specified.

[0013] The term "α-olefin" refers to a linear or branched compound of either carbon or hydrogen having at least one double bond between an α-carbon and a β-carbon. For the purposes of this specification and the claims appended thereto, when a polymer or copolymer is referred to as "poly-α-olefin," the α-olefin present in the polymer or copolymer is a polymerized form of α-olefin. The term "amorphous poly-α-olefin" refers to a poly-α-olefin in which the polymer chains are not arranged in a regular crystalline structure. The term "polymer" refers to any two or more identical or different repeating units / mer units or units. The term "homopolymer" refers to a polymer having identical 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 different units. When the term "different" refers to units, it means that the units differ from each other by at least one atom or are analogously different. Similarly, the definition of polymer as used herein includes homopolymers, copolymers, etc. For example, when a copolymer is said to have a "propylene" content of 10 wt% to 30 wt%, it is understood that the repeating units / mer units or simply units in the copolymer are derived from propylene in a polymerization reaction, and these derived units are present in 10 wt% to 30 wt% based on the mass of the copolymer.

[0014] The term "solution polymerization" refers to a polymerization process in which a polymer is dissolved in a liquid polymerization medium such as an inert solvent, monomer(s), or a blend thereof. Solution polymerization is typically homogeneous. The term "homogeneous polymerization" refers to a polymerization process in which the polymer product is dissolved in a polymerization medium. The system is preferably not turbid, as described in J. Vladimir Oliveira, C. Dariva, and JC Pinto, Ind. Eng. Chem. Res., 29, 2000, 4627. A homogeneous polymerization process is typically one in which at least 90 wt% of the product is dissolved in the reaction medium. As used herein, "Mn" refers to the number-average molecular weight of various polymers in a polymer material, "Mw" refers to the mass-average molecular weight of various polymers in a polymer material, and "Mz" refers to the z-average molecular weight of various polymers in a polymer material. The terms "Molecular Weight Distribution" (MWD) and "Polydispersion Index" (PDI) are used interchangeably and refer to the ratio of Mw to Mn. Unless otherwise specified, all molecular weights (e.g., Mw, Mn, Mz) are reported in units of g / mol. The term "Broad Orthogonal Comonomer Distribution" (BOCD) refers to a comonomer content profile with a positive gradient along the log Mw of the polymer.

[0015] In the following discussion, carbon-containing compounds such as hydrocarbons may be referred to using the abbreviation "Cn," where n refers to the number of carbon atoms in the compound, regardless of the number of hydrogen atoms or heteroatoms in the compound. When plus or minus signs are used, they represent the range of carbon atoms containing n or more carbon atoms, or n or fewer carbon atoms. For example, "C9+" refers to hydrocarbon compounds with 9 or more carbon atoms, and "C9-" refers to hydrocarbon compounds with 9 or fewer carbon atoms. 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 the periodic table is shown on the inside pages of the front cover of Advanced Inorganic Chemistry, 6th Edition by F. Albert Cotton et al. (John Wiley & Sons, Inc., 1999).

[0016] A detailed explanation is provided below. Each attached claim defines a separate invention, which, for the purpose of infringement, is deemed to include the various elements or limitations specified in the claim and equivalents thereof. Depending on the context, all references to “invention” may refer only to a specific concrete embodiment. In other cases, references to “invention” may refer to the subject matter described in one or more, but not necessarily all, claims. Each of the inventions will be described in further detail below, including specific embodiments, variations, and examples, but the invention is not limited to these embodiments, variations, or examples, and these embodiments, variations, or examples are included so that a person skilled in the art can make and use the invention when the information in this disclosure is used in conjunction with publicly available information and technology.

[0017] This specification discloses polymer blend compositions that may comprise a main polymer fraction having a high Mw of about 100,000 to about 300,000 and a melt flow rate (MFR) of about 0.1 g / 10 min to about 70.0 g / 10 min as measured according to ASTM D1238, and a smaller polymer fraction having a lower Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 50,000 cP as measured according to ASTM D-3236 (190°C). Both the main and smaller polymer fractions may comprise propylene-derived units and at least one other comonomer-derived units, such as ethylene-derived units. The content of at least one other comonomer-derived units in the smaller polymer fraction is at least 7 wt%, preferably at least 9 wt%, less than the content of at least one other comonomer-derived units in the main polymer fraction. The polymer blend composition may contain a main polymer fraction of about 60 wt% to about 95 wt% and a minor polymer fraction of about 5 wt% to about 35 wt%. The main polymer fraction may also contain at least one other comonomer-derived unit of about 10 wt% to about 30 wt%, preferably about 14 wt% to about 16 wt%, and the minor polymer fraction may contain at least one other comonomer-derived unit of about 2 wt% to about 8 wt%, preferably about 3 wt% to about 6 wt%. When subjected to a temperature-induced elution fractionation method, the main polymer fraction is preferably soluble in hydrocarbon solvents, such as xylene and / or orthodichlorobenzene, at -15°C, while the minor polymer fraction is preferably insoluble in hydrocarbon solvents at -15°C. The main polymer fraction may have low crystallinity or be amorphous, as indicated by its heat of fusion of approximately 10 J / g or less, as measured by differential scanning calorimetry (DSC). In contrast, the minor polymer fraction may have high crystallinity, as indicated by its higher heat of fusion. Furthermore, the triplicate stereoregularity of the main polymer fraction may be greater than that of the minor polymer fraction.

[0018] Surprisingly, the polymer blend compositions of the present invention disclosed herein (also known as “elastomers”) were found to have a broad or bimodal MWD and a heterogeneous broad orthogonal comonomer distribution (BOCD) ranging from about 2.7 to about 5.0, as measured by gel permeation chromatography (GPC). For each polymer blend composition, a CD gradient of 90 may be less than a CD gradient of 50. Polymers with a broad comonomer distribution may have chains with relatively high molecular weight at lower comonomer incorporations or chains with relatively low molecular weight at higher comonomer incorporations. Procedures that can be used to measure the CD gradient and molecular weight moment are described in the examples below. The polymer blend composition may exhibit unexpectedly desirable properties, such as high elasticity, high rigidity, and good flow properties, as indicated by an MFR in the range of about 80 to about 400 g / 10 min. Surprisingly, the blend composition may exhibit an isothermal crystallization half-life of about 0.3 min to about 3.0 min, preferably about 0.5 min to about 2.0 min, at 5°C, measured using DSC, faster than the usual crystallization rate. As a result, customers can achieve the desired properties of their end-use products using only the polymer blend composition disclosed herein, without the need to combine the composition with other polymers of different properties, and thus using only one conveyor system. Accordingly, the polymer blend composition disclosed herein provides customers with an inexpensive alternative to fulfill specific properties in their end products. Similarly, and perhaps more surprisingly, polymer blend compositions experience less pellet agglutination, potentially leading to fewer handling problems for customers. While not intended to be limited by theory, it is thought that because polymer blends crystallize faster than usual, polymer pellets can harden quickly after production, allowing them to remain free-flowing even after long storage periods. As a result, the pellets have a lower tendency to agglutinate, making them easier for customers to move around their storage facilities.

[0019] The polymer blend compositions disclosed herein are suitable for end-use products such as carpet backing sheets, which may have high filler content, melt-blown fibers, and propylene-based masterbatches for use in various polymer materials. A particularly suitable end-use product of the polymer blend compositions disclosed herein is a hot-melt adhesive (HMA). In one or more embodiments, the HMA composition may comprise about 1 wt% to about 40 wt%, preferably about 5 wt% to about 35 wt%, of the polymer blend composition. The HMA composition may also comprise other polymers, such as low-viscosity propylene-ethylene (C3 / C2) copolymers, high-viscosity C3 / C2 copolymers, amorphous poly-α-olefins (APAOs), linear α-olefins (LAOs), ethylene-vinyl acetate (EVA), and combinations thereof. The amount of APAO present in the HMA composition may be in the range of 0 wt% to about 75 wt%, preferably about 10 wt% to about 60 wt%. The amount of EVA present in the HMA composition may be in the range of 0 wt% to about 40 wt%, preferably about 25 wt% to about 35 wt%. A suitable EVA polymer may have a vinyl ester comonomer content of about 5 wt% to about 50 wt% or about 10 wt% to about 40 wt%, based on the total copolymer mass.

[0020] The HMA composition may contain other additives, such as tackifiers, waxes, antioxidants, diluents, such as oils and linear α-olefins (LAOs), and combinations thereof. Other suitable additives are technically well known. The term "tackifier" refers to a substance that can enhance the tackiness of the surface of an adhesive. The amount of tackifier present in the HMA composition may range from about 10 wt% to about 70 wt%, preferably from about 20 wt% to about 60 wt%. A suitable tackifier has 0% to about 15% aromaticity and a softening point of about 50°C to about 150°C, preferably from about 80°C to about 140°C. Examples of suitable commercially available tackifiers can be found in the examples below. The term "wax" refers to a substance that can lower the overall viscosity of an HMA composition. Adding wax can control the set time and adhesion of the HMA composition. The amount of wax present in the HMA composition may range from 0 wt% to about 30 wt%. For HMA compositions used in packaging, the amount of wax present is preferably in the range of about 15 wt% to about 30 wt%, more preferably in the range of about 20 wt% to about 25 wt%. For HMA compositions used in sanitary applications, the amount of wax present is preferably in the range of 0 wt% to about 20 wt%, more preferably in the range of about 5 wt% to about 10 wt%. Examples of suitable waxes include castor oil derivatives (HCO-wax), ethylene coter polymers, Fischer-Tropsch wax, microcrystalline wax, paraffin (petroleum) wax, polyolefin-modified wax, and polyolefin wax. Examples of suitable commercially available waxes can be found in the examples below.

[0021] The term "linear α-olefin" refers to an unbranched alkene hydrocarbon having a carbon-carbon double bond at the end (terminal) of a continuous carbon chain whose side chains are not branched. The amount of LAO diluent present in the HMA composition may be in the range of 0 wt% to about 15 wt%, preferably about 5 wt% to about 10 wt%. A suitable example of LAO is C24+ LAO, and C18+ LAO having a kinematic viscosity (ASTM D445) of about 4 cSt or less at 135°C is preferred. The LAO diluent may be present together with paraffinic hydrocarbon oil and / or paraffinic hydrocarbon wax, such as Fischer-Tropsch wax. The amount of oil present in the HMA composition may be in the range of 0 wt% to about 30 wt%, preferably about 5 wt% to about 20 wt%. Paraffinic hydrocarbon oil (e.g., paraffin white oil) or naphthalene hydrocarbon oil can be used in combination with the LAO diluents disclosed herein. Examples of suitable paraffinic or naphthalene hydrocarbon oils are shown below. nIt has a carbon number distribution and contains, on a mass basis, approximately 40% or more branched paraffins, or approximately 45% or more branched paraffins, or approximately 50% or more branched paraffins, or approximately 55% or more branched paraffins, or approximately 60% or more branched paraffins. Examples of suitable commercially available oils can be found in the examples below.

[0022] The term "antioxidant" refers to a substance that inhibits oxidation, such as high molecular weight hindered phenols and polyfunctional phenols. The amount of antioxidant present in an HMA composition may range from 0 wt% to approximately 1 wt%. A suitable commercially available antioxidant is Irganox® 1010 hindered phenol antioxidant, commercially available from BASF SE Corporation. Other suitable antioxidants include amines, hydroquinones, phenols, phosphites, and thioester antioxidants. Further details regarding the components of the HMA composition and the manufacturing process of the HMA composition can be found in U.S. Patents 10,633,564 and 10,336,921, the contents of which are incorporated herein by reference.

[0023] Manufacturing process for polymer blend compositions The polymer blend compositions disclosed herein can be produced by combining a main polymer fraction produced in a first reactor system with a smaller polymer fraction produced in a second reactor system parallel to the first reactor system. The polymerization process may be a solution polymerization process in which monomers, comonomers, and a catalyst system are contacted in a solution phase to form a polymer. A solvent may be present during the polymerization process. Suitable solvents for the polymerization process may include non-coordinating inert liquids. Examples include linear and branched hydrocarbons, e.g., isobutane, butane, pentane, isopentane, hexane, isohexane, heptane, octane, dodecane, and mixtures thereof; cyclic and alicyclic hydrocarbons, e.g., cyclohexane, cycloheptane, methylcyclohexane, methylcycloheptane, and mixtures thereof, e.g., Isopar®, commercially available from ExxonMobil; perhalogenated hydrocarbons, e.g., perfluorinated alkanes, and chlorobenzene; and aromatic compounds and alkyl-substituted aromatic compounds, e.g., benzene, toluene, mesitylene, and xylene. Suitable solvents include liquid olefins that can act as monomers or comonomers, such as ethylene, propylene, 1-butene, 1-hexene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-octene, 1-decene, and mixtures thereof. In preferred embodiments, aliphatic hydrocarbon solvents, such as isobutane, butane, pentane, isopentane, hexane, isohexane, heptane, octane, dodecane, and mixtures thereof, as well as cyclic and alicyclic hydrocarbons, such as cyclohexane, cycloheptane, methylcyclohexane, methylcycloheptane, and mixtures thereof, are used as solvents. One preferred aliphatic hydrocarbon is Isobar®, i.e., a mixture of alkanes, isoalkanes, and cycloalkanes commercially available from Dow Chemical Company.

[0024] A suitable solution polymerization process for preparing the polymer blend compositions disclosed herein is generally shown in Figure 1 and is further detailed in U.S. Patent No. 9,359,535, which is incorporated herein by reference in its entirety. In an exemplary embodiment, the process may be achieved by a system 10 comprising a first reactor 20, a second reactor in parallel with the first reactor 20, a liquid phase separator 60, a liquefaction vessel 70, and a pelletizer 80. The first reactor 20 and the second reactor 40 may be, for example, continuous stirred-tank reactors. The first reactor 20 may receive a first feed 22 of monomers, a second feed of at least one other comonomer, and a third feed of a catalyst. The first reactor 20 may also receive a feed of solvent and activator. The solvent and / or activator feed may be combined with the first feed 22, the second feed 24, or the third feed 26, or the solvent and activator may be supplied to the reactor in separate feedstreams 28, 30. The first polymer, i.e., the main polymer fraction, is produced in the first reactor 20 and may be withdrawn from the first reactor 20 via the first product stream 32. The first product stream 32 may contain the first polymer, the solvent, and any unreacted monomers and / or comonomers (hereinafter "monomer / comonomer").

[0025] The second reactor 40 may receive a fourth feed of monomers, a fifth feed 44 of at least one other comonomer, and a sixth feed 46 of a catalyst. The second reactor 40 may also receive a feed of solvent and activator. The solvent and / or activator feed may be combined with any of the fourth feed 42, fifth feed 44, or sixth feed 46, or the solvent and activator may be supplied to the reactor in separate feedstreams 48, 50. The second polymer, i.e., the second polymer fraction, is produced in the second reactor 40 and may be withdrawn from the second reactor 40 via the second product stream 52. The second product stream 52 may contain the second polymer, the solvent, and any unreacted monomers / comonomers.

[0026] It should be understood that by utilizing any number of additional reactors, other polymers can be produced that can be blended with the first and second products. The first product stream 32 and the second product stream 52 can be combined to produce a bimodal blend stream 54 in which the first product is the main polymer fraction of the polymer blend composition disclosed herein and the second product is its minor polymer fraction. For example, the first product stream 32 and the second product stream 52 can be used to supply the first and second polymers to a mixing vessel, such as a mixing tank equipped with a stirrer, to blend the polymers. Next, the bimodal blend stream 54 can be supplied to the liquid phase separation vessel 60 to produce a polymer-rich phase and a polymer-lean phase. The polymer-lean phase contains solvent and may be substantially polymer-free. At least a portion of the polymer-lean phase can be withdrawn from the liquid phase separation vessel 60 via the solvent recirculation stream 64. The solvent recirculation stream 64 may further contain unreacted monomers / comonomers. At least a portion of the polymer-rich phase can be withdrawn from the liquid phase separation vessel 60 via the polymer-rich stream 62.

[0027] In any embodiment, the liquid phase separation vessel 60 can operate on the principle of lower critical solution temperature (LCST) phase separation. This technique utilizes the thermodynamic principle of spinodal decomposition to create two liquid phases. One liquid phase is substantially free of polymer, and the other liquid phase contains a polymer dissolved at a higher concentration than a single liquid feed to the liquid phase separation vessel 60. As described in U.S. Patent Publication 2015 / 0322303, whose entire contents are incorporated herein by reference, achieving the formation of two liquid phases using a liquid phase separation vessel 60 utilizing spinodal decomposition has been found to be an effective method for separating the solvent from a bimodal polymer blend, particularly when one of the polymers in the blend has a mass-average molecular weight of 100,000 g / mol, and more particularly between 10,000 g / mol and 60,000 g / mol. It has also been found that the concentration of polymer in the polymer lean phase can be further reduced by the selection of a catalyst.

[0028] Looking back at Figure 1, immediately after leaving the liquid phase separation container 60, the polymer-rich stream 62 may then be supplied to the liquefaction container 70 for further polymer recovery. In either embodiment, the polymer-rich stream 62 may also be supplied to a low-pressure separator before being supplied to the inlet of the liquefaction container 70. Inside the container, the polymer composition may be exposed to a vacuum within the container so that at least a portion of the solvent is removed from the polymer composition and the temperature of the polymer composition decreases, thereby forming a second polymer composition containing a bimodal polymer blend and having a lower solvent content and lower temperature than when the polymer composition was introduced into the container. The polymer composition may then be discharged from the outlet of the container via the discharge stream 72. The liquefaction container 70 may be a liquefaction apparatus known in the art. Any apparatus capable of removing the solvent from the polymer melt and performing the evaporative cooling described herein can be used. A more detailed description of the operation of a liquefaction apparatus suitable for use herein can be found in U.S. Patent No. 12 / 972,140, ​​which is incorporated herein by reference in its entirety. Suitable liquefaction apparatuses are commercially available, for example, from LIST USA, Inc.

[0029] Looking back at Figure 1, the cooled discharge stream 72 exiting the liquefaction container 70 can be supplied to the pelletizer 80. There, the bimodal polymer blend is discharged through the pelletizing die as formed pellets 82. Polymer pelletizing is achieved by underwater, hotface, strand, water ring, or other similar pelletizers. Preferably, an underwater pelletizer is used, but other equivalent pelletizing units known to those skilled in the art may also be used. The general techniques of underwater pelletizing are known to those skilled in the art. Examples of useful underwater pelletizing apparatuses can be found in U.S. Patents 7,033,152; 7,226,553; and 7,470,118, the contents of which are incorporated herein by reference.

[0030] Monomers and comonomers The monomer is propylene (C3) or may contain propylene (C3). At least one other comonomer may be ethylene (C2), a C4-C20 olefin, or a combination thereof, or may contain these. The olefin comonomer may be linear, branched, or cyclic. A suitable cyclic olefin may be strained or unstrained monocyclic or polycyclic and may optionally contain heteroatoms and / or one or more functional groups. The comonomer is preferably a C2 or C4-C10α olefin. The comonomer concentration in the first reactor may be in the range of about 10 wt% to about 20 wt%, preferably about 14 wt% to about 16 wt%. The comonomer concentration in the second reactor system may be in the range of about 2 wt% to about 6 wt%, preferably about 3 wt% to about 5 wt%. Specific examples of suitable comonomers other than ethylene include butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, norbornene, norbornadiene, dicyclopentadiene, cyclopentene, cycloheptene, cyclooctene, cyclooctadiene, cyclododecene, 7-oxanorbornene, 7-oxanorbornadiene, their substituted derivatives, and their isomers, preferably hexene, heptene, octene, nonene, decene, dodecene, cyclooctene, 1,5-cyclooctadiene, l-hydroxy-4-cyclooctene, 1-acetoxy-4-cyclooctene, 5-methylcyclopentene, cyclopentene, dicyclopentadiene, norbornene, norbornadiene, and their respective homologs and derivatives, preferably norbornene, norbornadiene, and dicyclopentadiene.

[0031] Catalytic converter system The polymer blend compositions disclosed herein can be prepared using one or more catalyst systems. As used herein, a "catalyst system" includes at least a transition metal compound, also referred to as a catalyst precursor, and at least one activator. Contacting the transition metal compound (catalyst precursor) and the activator in a solution upstream of each polymerization reactor or within each polymerization reactor provides the catalytic active component (catalyst) of the catalyst system. Any given transition metal compound or catalyst precursor can provide various activators and catalytic active components (catalysts), providing a diverse range of catalysts that can be incorporated into the processes provided herein. The catalyst system can optionally include an impurity scavenger. Each of these components is described in further detail below.

[0032] Any metallocene catalyst generally known in the art can be utilized as the catalyst. Suitable metallocene catalysts can be bridged bisindenyl metallocenes having the general formula (In 1 )Y(In 2 )MX2. In the formula, In 1 and In 2 are the same substituted or unsubstituted indenyl groups bonded to M, bridged by Y, where Y is a bridging group having 1 to 8 atoms in a direct chain connecting In 1 to In<000001l>and the direct chain contains C, Si, or Ge; M is a Group 3, 4, 5, or 6 transition metal; and X2 is a leaving group. In 1 and In 2 can be substituted or unsubstituted. When In 1 and In 2 are substituted with one or more substituents, the substituents can be selected from the group consisting of halogen atoms, C1-C10 alkyl, C5-C15 aryl, C6-C25 alkylaryl, and Si-containing, N-containing, or P-containing alkyl or aryl. Each leaving group X can be alkyl, preferably methyl, or a halide ion, preferably chloride ion, or fluoride ion. Exemplary metallocene compounds of this type include μ-dimethylsilylbis(indenyl)hafnium dimethyl and μ-dimethylsilylbis(indenyl)zirconium dimethyl.

[0033] In any embodiment, the metallocene compound is of the general formula (In 1 )Y(In 2 ) may be a crosslinked bisindenyl metallocene having MX2. In the formula, In 1 and In 2 is the same 2,4-substituted indenyl group bonded to M, and is bridged by Y, where Y is In 1 In 2 The number of atoms in the direct chain that binds to it is 1 to 8, and the direct chain is a bridging group containing C, Si, or Ge; M is a group 3, group 4, group 5, or group 6 transition metal; and X2 is a leaving group. 1 and In 2 The group is substituted at the 2-position by a C1-C10 alkyl group, preferably a methyl group, and at the 4-position by a substituent selected from the group consisting of C5-C15 aryl, C6-C25 alkylaryl, and Si-containing, N-containing, or P-containing alkyl or aryl groups. Each leaving group X can be an alkyl group, preferably a methyl group, or a halide ion, preferably a chloride ion or a fluoride ion. Examples of this type of metallocene compound include (dimethylsilyl)bis(2-methyl-4-(3',5'-di-tert-butylphenyl)indenyl)zirconiumdimethyl, (dimethylsilyl)bis(2-methyl-4-(3',5'-di-tert-butylphenyl)indenyl)hafniumdimethyl, (dimethylsilyl)bis(2-methyl-4-naphthylindenyl)zirconiumdimethyl, (dimethylsilyl)bis(2-methyl-4-naphthylindenyl)hafniumdimethyl, (dimethylsilyl)bis(2-methyl-4-(N-carbazyl)indenyl)zirconiumdimethyl, and (dimethylsilyl)bis(2-methyl-4-(-carbazyl)indenyl)hafniumdimethyl.

[0034] A particularly advantageous catalyst that can be used in any embodiment is shown in the following formula I. [ka]

[0035] In any embodiment, M is a group IV transition metal atom, preferably a group IVB transition metal, more preferably hafnium or zirconium, and X is an alkyl, preferably methyl, or halide ion, preferably chloride or fluoride ion. Methyl or chloride leaving groups are most preferred. In any embodiment, RI and R2 are independently selected from the group consisting of hydrogen, phenyl, and naphthyl. RI is preferably the same as R2. Particularly advantageous species of formula I are dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dimethyl, dimethylsilylbis(2-methyl-4-phenylindenyl)hafnium dichloride, and dimethylsilylbis(2-methyl-4-phenylindenyl)hafnium dimethyl.

[0036] Another advantageous catalyst that can be used in any embodiment is shown in formula II. [ka]

[0037] In any embodiment, M is a group IV transition metal atom, preferably a group IVB transition metal, more preferably hafnium or zirconium, and X is an alkyl, preferably methyl, or halide ion, preferably chloride or fluoride ion. Methyl or chloride leaving groups are most preferred. In any embodiment, Rl and R2 can be independently selected from the group consisting of hydrogen, phenyl, and naphthyl. Rl is preferably the same as R2. Particularly advantageous species of formula II are dimethylsilylbis(indenyl)hafniumdimethyl, dimethylsilylbis(indenyl)hafnium dichloride, dimethylsilylbis(indenyl)zirconiumdimethyl, and dimethylsilylbis(indenyl)zirconium dichloride.

[0038] In any embodiment, the activator of the catalyst system may include a cationic component. In any embodiment, the cationic component is of formula [R1 R 2 R 3 AH] + It may have. In the formula, A is nitrogen and R 1 and R 2 This, together, is -(CH2) a - A group (where a is 3, 4, 5, or 6) and together with a nitrogen atom, it forms a 4-membered, 5-membered, 6-membered, or 7-membered non-aromatic ring, and one or more aromatic rings or heteroaromatic rings may be condensed to this ring via adjacent ring carbon atoms, R 3 is a C1, C2, C3, C4, or C5 alkyl, or N-methylpyrrolidinium or N-methylpiperidinium. Alternatively, in any embodiment, the cationic component is of formula [R n AH4_ n ] + It may have the following: In the formula, A is nitrogen, n is 2 or 3, all R are the same and are C1-C3 alkyl groups, such as trimethylammonium, trimethylanilinium, triethylammonium, dimethylanilinium, and dimethylammonium.

[0039] Any catalyst system resulting from any combination of metallocene compounds, cationic activators, and anionic activators provided herein shall be deemed expressly disclosed herein. Furthermore, combinations of two different activators may be used with the same or different metallocenes. In any embodiment, the activator of the catalyst system disclosed herein may include an anionic component, [Y]. In any embodiment, the anionic component is of formula [B(R 4 )4] - It is a non-coordinating anion (NCA) having R in the formula. 4 The substituent is an aryl group or a substituted aryl group, and one or more substituents thereon may be the same or different, selected from the group consisting of alkyl, aryl, halogen atom, aryl halide, and haloalkylaryl group. The substituent may be a perhalide aryl group or a perfluorinated aryl group, such as perfluorophenyl, perfluoronaphthyl, and perfluorobiphenyl.

[0040] In summary, the cationic and anionic components of the catalyst systems disclosed herein form an activator compound. In any embodiment, the activator may be N,N-dimethylanilinium-tetra(perfluorophenyl) borate, N,N-dimethylanilinium-tetra(perfluoronaphthyl) borate, N,N-dimethylanilinium-tetrakis(perfluorobiphenyl) borate, N,N-dimethylanilinium-tetrakis(3,5-bis(trifluoromethyl)phenyl) borate, triphenylcarbenium-tetra(perfluorophenyl) borate, triphenylcarbenium-tetra(perfluoronaphthyl) borate, triphenylcarbenium-tetrakis(perfluorobiphenyl) borate, or triphenylcarbenium-tetrakis(3,5-bis(trifluoromethyl)phenyl) borate. Non-coordinating activators can be used with catalysts of formulas I and II. Dimethylanilinium tetrakis(heptafluoronaphthyl) borate is a particularly advantageous activator. Further disclosures relating to suitable catalytic systems can be found in International Patent Publication WO / 2013 / 134038, the entirety of which is incorporated herein by reference. [Examples]

[0041] Examples: The above considerations can be further described by referring to the following non-limiting examples. Propylene-ethylene copolymers (Examples 1-6) were produced using two laboratory-scale continuous reactors in parallel mode as follows. In the presence of rac-dimethylsilylbis(indenyl)hafniumdimethyl and dimethylaniliniumtetrakis(heptafluoronaphthyl)borate as catalyst and activator, respectively, a propylene feedstream and an ethylene comonomer feedstream were subjected to propylene polymerization conditions in each reactor to produce C3-C2 copolymers in a mass ratio of 70-30 (amount produced in the first reactor:amount produced in the second reactor). The streams exiting each reactor were combined to produce a product stream containing the main polymer fraction and the minor polymer fraction of the C3-C2 polymer blend composition. The product stream, containing 9-16% polymer by mass, was then heated to between approximately 200°C and 205°C under a pressure of approximately 11 MPa (1600 psig). The stream was then supplied to a high-pressure separator with an operating pressure of 4.1 MPa (600 psig). The pressure drop induced a stream into two phase regions above the lower critical solution temperature, separating the product into two liquid phases based on density. After sedimentation, the product stream separated into a polymer-rich phase located at the bottom of the high-pressure separator and a polymer-lean phase located above the high-pressure separator. The polymer-rich phase was introduced into a pelletizer to form pellets containing the final polymer blend composition, while the polymer-lean phase was returned to the reactor for recycling. For Ex. 1-6, the comonomer (C2) content of the C3-C2 copolymer produced in each reactor, the melt flow rate (MFR) of the C3-C2 copolymer produced in the first reactor, and the MFR and / or Brookfield viscosity (BV) at 190°C of the C3-C2 copolymer produced in the second reactor were measured. These are shown in Table 1 below. Furthermore, Table 1 below shows the difference in C2 content (ΔC2) between the C3-C2 copolymers produced in each reactor, the C2 content of the final polymer pellet, and the MFR of the final polymer pellet.

[0042] The above procedure for preparing polymer blend compositions of Ex.1-6 was repeated four times, except that the amount of C2 supplied to each reactor was adjusted so that ΔC2 was greater for Ex.1-6 than for C.Ex.1-4 (Comparative Examples 1-4). As shown in Table 1 below, the same properties measured for Ex.1-6 were also measured for C.Ex.1-4. Furthermore, commercially available C3-C2 copolymers (unblended) from ExxonMobil, which have a narrow MWD and a nearly uniform distribution of C2 comonomers across the molecular weight of the polymer chain, were obtained for comparison (Comparative Examples 5 and 6). The C2 content and MFR values ​​of the copolymers of C.Ex.5-6 are shown in Table 1 below.

[0043] [Table 1] * BV is based on the correlation between MFR and BV.

[0044] For Ex.1-4, the MFR of the C3-C2 copolymer produced in reactor 1 differs significantly from that of the C3-C2 copolymer produced in reactor 2, but the difference in C2 content between the copolymer produced in reactor 1 and the copolymer produced in reactor 2 is only about 4-5 wt%. For Ex.1-6, not only are the MFRs significantly different, but the difference in C2 content between the copolymer produced in reactor 1 and the copolymer produced in reactor 2 also exceeds 9 wt%.

[0045] Figure 2a shows graphs of the molecular weight distribution and comonomer distribution measured using GPC-4D for a C3-C2 blend composition produced with Ex.3 (12.4 wt% C2, 87 MFR), as well as for commercially available C3-C2 copolymer pellets of C.Ex.5 (13.3 wt% C2, 45 MFR) and C.Ex.6 (6 wt% C2, 1200 MFR). Both commercial grades exhibit a unimodal MWD, but the inventive blend composition of Ex.3 clearly showed a bimodal MWD, as shown in Figure 2b by curve fitting of peak 1 and peak 2 using its molecular weight moment. Surprisingly, the blend composition of Ex.3 showed a broad, heterogeneous orthogonal distribution of C2 across the molecular weight range. In contrast, the commercial grades showed a nearly uniform comonomer distribution of C2 comonomers across the molecular weight range, as represented by the horizontal line in Figure 2a. Therefore, it is considered that in the inventive blend compositions Ex.1-6, the high molecular weight chains had a high C2 content, while the low molecular weight chains had a low C2 content. Such molecular structures were unexpected for C3-based elastomers.

[0046] As shown in Table 2, the molecular weight moments and comonomer distribution (CD) gradients of the blended compositions of Ex.1-6 and C.Ex.1-4, as well as the commercially available grades of C.Ex.5-6, were also determined. The CD gradient was determined by first curve fitting of the comonomer content with respect to molecular weight change to an n-th degree polynomial using a MATLAB® program. The range of n was typically between 2 and 4. The derivative of the curve was obtained at various molecular weight points, which are 50%, 75%, and 90% of the molecular weight range, respectively. For example, to determine the 50% point on the x-axis, the minimum molecular weight (Mw) of a specific dataset was used. min ) and maximum molecular weight (Mw max The difference between ) was first confirmed. The x-value for a gradient of 50 is Mw min +0.50*(Mw max -Mw minThe calculation was performed as follows. The absolute value of the derivative was determined at that point to find a gradient of 50. A gradient value in the range of 0 to 2 was considered to represent a uniform comonomer distribution, while a gradient > 2 was considered to represent a heterogeneous comonomer distribution. Surprisingly, the polymer blend compositions Ex. 1-6 showed a decreasing trend from a gradient of 50 to a gradient of 90. This suggests a broad orthogonal distribution of comonomers, i.e., high molecular weight chains have a higher comonomer content, while low molecular weight chains have a lower comonomer content. The blend compositions Ex. 3 and Ex. 6 unexpectedly showed a broad MWD of 3.0 or higher.

[0047] [Table 2]

[0048] As shown in Table 3 below, the polymer blend composition of Ex.3 was analyzed by temperature-refined elution fractionation (TREF) for comparison with the TREF-GPC data of polymers A, B, and C (Comparative Examples 7, 8, and 9) of U.S. Patent No. 9,359,535. All of these examples showed a soluble fraction and one or two crystallized (insoluble) fractions. Each temperature in Table 3 represents the elution temperature of the fraction. The amount of polymer (wt%) present in the fraction at this elution temperature, as well as the Mw and MWD (Mw / Mn) of that fraction, are shown in parentheses. The soluble fractions of each polymer in Ex.7-9 each had a lower Mw than their insoluble fractions, while the soluble fraction of the polymer blend composition of Ex.3 had a much higher Mw than its insoluble fraction.

[0049] Table 3: TREF-GPC data for Ex.3 and C.Ex.7-9 [Table 3]

[0050] As shown in Table 4, the non-isothermal crystallization temperature (Tc) and melting temperature (Tc) are as follows for the polymer blend compositions of Ex.1-3 and C.Ex.1-4, and for the polymers of C.Ex.5-6. m ) and the isothermal crystallization half-life (t) at 5°C, 7°C, and 10°C. 1 / 2 The molecular weight (T) was measured by differential scanning calorimetry (DSC). The presence of low molecular weight and low C2 fraction in polymer blend compositions Ex.1-3 was relatively higher than that of polymers C.Ex.1-6. m and T c These inventive compositions yield values. The presence of low C2 fractions also resulted in a faster crystallization rate, as indicated by a significant decrease in crystallization half-times at 5°C, 7°C, and 10°C. The crystallization rate of the Ex.3 blend composition is approximately 10 times faster than that of the commercially available grade of C.Ex.6, which is advantageous for specific applications.

[0051] Table 4: Isothermal and non-isothermal DSC data for Ex.1-3 and C.Ex.1-6 [Table 4]

[0052] Ex.4-6 The isotactic (mm) triple stereoregularity and regio defects (array length) of the C3-C2 copolymers (i.e., the main polymer fraction and minor polymer fraction of the polymer blend composition, respectively) formed in reactors R1 and R2. 13 The endothermic T of these C3-C2 polymers was determined by 13C NMR. m and heat of fusion (H f) was also measured by DSC. This data is provided in Table 5 below. The stereoregularity of the different fractions formed in reactors R1 and R2 has an overall effect on the crystallinity of the final polymer blend composition. The stereoregularity of the R1 fraction is equal to or greater than that of the R2 fraction and differs from that shown for polymer C of U.S. Patent No. 9,359,535 (see Table 4 and Claim 1). In addition, the amount of positional defects in the R2 fraction is significantly lower than that of the R1 fraction, which results in a higher T in the blend composition. m This helps to achieve this and leads to good pellet stability. f The value was much higher in the R2 fraction than in the R1 fraction. Since the heat of fusion is an indicator of crystallinity, this trend indicates that the R2 fraction had a higher degree of crystallinity than the R1 fraction.

[0053] Table 5: Additional characteristics for Ex.4~6 [Table 5]

[0054] Four different carpet backing formulations (Examples 7, 8, 9, and 10) were prepared using the polymer blend compositions formed in Examples 2, 4, 5, and 6, without blending any other C3 polymers. For comparison, a carpet backing formulation (Comparative Example 10) containing three C3 polymers (Vistamaxx® 6502, Vistamaxx® 8880, and Achieve® Advanced PP6936G2, all commercially available from ExxonMobil) was prepared. The other components in the carpet backing formulations of Ex.7-10 and C.Ex.10 were identical, as shown in Table 6 below. It should be noted that Exxelor® PE1040 coupling agent and Escorez® 1315 tackifier are commercially available from ExxonMobil, Ampacet 19470 PE black masterbatch is commercially available from Ampacet Corporation, and Lhoist-325 high-calcium limestone is commercially available from Lhoist Group. Various physical properties of the carpet backing formulations were measured and are shown in Table 6. The carpet backing formulations Ex.8-10 showed an excellent balance of flow properties and mechanical performance comparable to the carpet backing formulation C.Ex.7. The carpet backing formulations Ex.8-10 did not require the use of multiple conveyors to transport the commercially available grade C3 polymer contained therein, as was required for the carpet backing formulation C.Ex.7. This allows the carpet backing formulations of the present invention to be manufactured at a much lower cost. Surprisingly, the carpet backing formulations Ex.8-10 showed significantly better and lower growth force (less than 0.2 MPa (30 psi)) than the carpet backing formulation C.Ex.7.

[0055] Table 6: Composition and properties of formulations of Ex.7-10 and C.Ex.7 [Table 6]

[0056] Two different hot melt adhesive (HMA) formulations (Examples 11 and 12) were prepared using the polymer blend composition formed in Ex. 5. One contained Vistamaxx® 8380 low viscosity C3 / C2 copolymer (Ex. 11), and the other contained Vistamaxx® 8780 low viscosity C3 / C2 copolymer (Ex. 12). For comparison with Ex. 11, two HMA formulations were prepared (Comparative Examples 8 and 9). One contained only Vistamaxx® 8380 (C.Ex. 8), and the other contained both Vistamaxx® 8380 and Vistamaxx® 6502 high viscosity C3 / C2 copolymer (C.Ex. 9). For comparison with Ex. 12, an HMA formulation containing Vistamaxx® 8780 (Comparative Example 10) was prepared. Table 7 shows the other components in the HMA formulations of Ex.11-12 and C.Ex.8-10. Note that Escorez® 5400 hydrogenated tackifier, Primol® 352 oil, and Parvan 1580 paraffin wax are commercially available from ExxonMobil, and Irganox® 1010 antioxidant is commercially available from BASF SE Corp. Various physical properties of the HMA formulations were measured. These, including the softening point (SP) of the tackifier, are presented in Table 7. Adding the polymer blend formulation of Ex.5 to the HMA formulation of Ex.11 instead of Vistamaxx® 6502 improved the HMA viscosity compared to C.Ex.9, resulting in lower temperature applications. The HMA formulation of Ex.11 also unexpectedly showed higher peel strength than the HMA formulations of C.Ex.8-9. Surprisingly, the addition of polymer blend formulations and paraffin wax from Ex.5 increased the peel strength of the HMA formulation in Ex.12.

[0057] Table 7: Composition and properties of formulations Ex.11-12 and C.Ex.8-10 [Table 7]

[0058] Using the polymer blend composition formed in Ex.5, two different HMA formulations (Examples 13 and 14) containing the Vistamaxx® 8380 low-viscosity C3 / C2 copolymer were prepared. For comparison with Ex.13-14, an HMA formulation containing Vistamaxx® 8380 as the sole C3 copolymer was prepared (Comparative Example 11). As shown in Table 8 below, the other components of the HMA formulations of Ex.13-14 and C.Ex.11 were identical except that the formulation of Ex.14 contained Escorez® 5615 tackifier (a hydrogenated tackifier with a high softening point (SP) and high aromaticity, commercially available from ExxonMobil), and the formulations of Ex.13 and C.Ex.11 contained Eastotac® H-130W tackifier (a hydrogenated C5 tackifier with a high SP, commercially available from Eastman Chemical Company). It should be noted that Epolene® C-13 is a commercially available branched, low-viscosity polyethylene homopolymer from Westlake Chemical. Various physical properties of the HMA formulations were measured and are shown in Table 8. Adding the polymer blend formulation Ex. 5 to the HMA formulations Ex. 13-14 unexpectedly improved the peel strength.

[0059] Table 8: Composition and properties of formulations Ex.13-14 and C.Ex.11 [Table 8]

[0060] Two different HMA formulations were prepared using the polymer blend composition formed in Ex.5 (Examples 15 and 16). One contained Vistamaxx® 6502 (Ex.16), and the other was not mixed with any other polymers (Ex.15). For comparison with Ex.15-16, an HMA formulation containing Vistamaxx® 6502 as the sole C3 polymer was prepared (Comparative Example 12). As shown in Table 9 below, all other components of the HMA formulations Ex.15-16 and C.Ex12 were identical. Note that Escorez® 2203 non-hydrogenated C5 / C9 tackifier is commercially available from ExxonMobil, Nyflex 223B oil is commercially available from Nynas AB, and Sasolwax® H1 is commercially available from Sasol Chemicals. Various physical properties of the HMA formulations were measured. They are shown in Table 9. Adding the polymer blend formulation of Ex.5 to the HMA formulations of Ex.15-16 improved the HMA viscosity compared to C.Ex.12. This allows for lower temperature applications. Surprisingly, the combined use of the polymer blend formulation of Ex.5 and Vistamaxx™ 6502 (Ex.16) improved the peel strength of the HMA formulation of Ex.16.

[0061] Table 9: Composition and properties of formulations Ex.15-16 and C.Ex.12 [Table 9]

[0062] Three different HMA formulations were prepared using the polymer blend composition formed in Ex.5 (Examples 17-19). The HMA formulation in Ex.19 contained Aerefin® 180 C3 polymer, commercially available from Eastman Chemical Company, while the HMA formulations in Ex.17-18 contained different amounts of REXtac® amorphous poly-α-olefin (APAO), commercially available from REXtac LLC. For comparison with Ex.17-18, an HMA formulation containing REXtac® APAO was prepared. Other components used in the HMA formulations of Ex.17-19 and C.Ex13 are shown in Table 10 below. Note that Escorez® 5637 is a high-SP hydrogenated aromatic tackifier commercially available from ExxonMobil, and Regalite® R1090 tackifier is a C9 hydrogenated tackifier commercially available from Eastman Chemical Company. Various physical properties of the HMA formulations were measured and are shown in Table 10. Adding a significant amount of APAO along with the polymer blend formulation from Ex. 5 to the HMA formulation from Ex. 18 resulted in significantly higher peel strength.

[0063] Table 10: Composition and properties of formulations Ex.17-19 and C.Ex.13 [Table 10]

[0064] Two different HMA formulations were prepared using the polymer blend composition formed in Ex.5 (Examples 20 and 21). One contained Vistamaxx® 8880 (Ex.20), and the other contained both Vistamaxx® 8880 and Vistamaxx® 6502 (Ex.21). For comparison with Ex.20-21, a commercially available HMA from HB Fuller Company, namely HL 1486, was obtained (Comparative Example 14). As shown in Table 11 below, the HMA formulations of Ex.20 and Ex.21 contained different tackifiers and different oils, but the same antioxidant. In addition, the HMA formulation of Ex.20 contained C24+ linear α-olefin (LAO), while the HMA formulation of Ex.21 did not contain LAO. Various physical properties of the HMA formulations were measured. They are shown in Table 11. Adding the polymer blend formulation of Ex.5 to the HMA formulation of Ex.20 improved the HMA viscosity at 140°C and 150°C compared to C.Ex.14.

[0065] Table 11: Composition and properties of formulations Ex.20-21 and C.Ex.14 [Table 11]

[0066] Three different HMA formulations were prepared using the polymer blend composition formed in Ex.5 (Examples 22-24). Two contained different amounts of Vistamaxx® 8880 (Ex.22-23), and one did not contain any other C3 polymers (Ex.24). For comparison with Ex.22-24, an HMA formulation containing Vistamaxx® 8880, Vistamaxx® 8780, and Vistamaxx® 6502 (Comparative Example 15) was prepared. Other components used in the HMA formulations of Ex.22-24 and C.Ex15 are shown in Table 12 below. Note that Escorez® 5415 is a commercially available hydrogenated tackifier from ExxonMobil. Various physical properties of the HMA formulations were measured. These are shown in Table 12. Adding the polymer blend formulation of Ex.5 to the HMA formulations of Ex.22-24 improved the HMA viscosity compared to C.Ex.15. This allows for the application of HMA at lower temperatures.

[0067] Table 12: Composition and properties of formulations Ex.22-24 and C.Ex.15 [Table 12]

[0068] Three different HMA formulations were prepared using the polymer blend composition formed in Ex. 5 (Examples 25-27). One contained no other polymers (Ex. 25), one contained Vistamaxx® 6102 high viscosity C3 / C2 copolymer (Ex. 26), and one contained Vistamaxx® 6202 high viscosity C3 / C2 copolymer (Ex. 27). For comparison with Ex. 25, an HMA formulation containing Vistamaxx® 8880 and Vistamaxx® 6502 was prepared (Comparative Example 16). For comparison with Ex. 26-27, an HMA formulation containing Vistamaxx® 8880, Vistamaxx® 5202, and Vistamaxx® 6102 was prepared (Comparative Example 17). Other components of the HMA formulations in Ex. 25-27 and Ex. 16-17 are shown in Table 13 below. Various physical properties of the HMA formulation were measured. These are also presented in Table 13.

[0069] Table 13: Composition and properties of formulations Ex.25-27 and C.Ex.16-17 [Table 13]

[0070] Two different HMA formulations were prepared using the polymer blend composition formed in Ex.5 (Examples 28 and 29). Both HMA formulations (Ex.28-29) contained Escorene® Ultra UL 7710 ethylene-vinyl acetate (EVA) copolymer, Escorez® 5600, Sasolwax® H1, and Irganox® 1010, all commercially available from Exxon. The HMA formulation in Ex.29 also contained C24+LAO. For comparison with Ex.28-29, a commercially available HMA from HB Fuller Company, namely Advantra® PHC 9256 (Comparative Example 18), was also obtained. For comparison with Ex.28-29, a formulation containing Escorene® Ultra UL 7710, Escorez® 5600, and Sasolwax® H1 (Comparative Example 19) was also prepared. Various physical properties of the HMA formulations were measured. These, including the shear adhesion failure temperature (SAFT) and peel adhesion failure temperature (PAFT), are shown in Table 14 below. When the polymer blend formulation of Ex.5 was added to the HMA formulation of Ex.28, which also contained an EVA copolymer, the heat resistance (PAFT) was unexpectedly improved and the set time shortened compared to the HMA formulation of C.Ex.19.

[0071] Table 14: Composition and properties of formulations Ex.28-29 and C.Ex.18-19 [Table 14]

[0072] Two different HMA formulations were prepared using the polymer blend composition formed in Ex. 5 (Examples 30 and 31). Both HMA formulations (Ex. 30-31) contained Affinity® GA 1950 polyolefin elastomer, Escorez® 5320 high-SP hydrogenated tackifier, Sasolwax® H1, and Irganox® 1010, all commercially available from Dow Chemical Company. The HMA formulation in Ex. 31 also contained C24+LAO. For comparison with Ex. 30-31, an HMA formulation containing Affinity® GA 1950, Escorez® 5320, and Sasolwax® H1 (Comparative Example 20) was prepared. Various physical properties of the HMA formulations were measured. These are shown in Table 15 below. When the polymer blend formulation of Ex.5 was added to the HMA formulation of Ex.30, which also contains polyolefin elastomer, the heat resistance (PAFT) was improved and the set time was shortened compared to the HMA formulation of C.Ex.20.

[0073] Table 15: Composition and properties of formulations Ex.30-31 and C.Ex.20 [Table 15]

[0074] Preparation process of HMA formulations (Tables 7-13) All the raw materials for each formulation were weighed into 3.8-liter (1-gallon) cans and heated in a 180°C oven for approximately 3 hours (or until all components were clearly melted). The cans were then placed in a 180°C heating mantle and mixed for 30-40 minutes with a mixer blade equipped with numerous blades around the rim, the blades having solid discs bent up and down in an alternating pattern around their periphery. As soon as each mixture was clearly homogenized, it was added to a melting tank and allowed to equilibrate to the applied temperature. The formulations in Tables 7-10 were prepared by bonding as follows: Each HMA formulation was melted and transferred to a polyethylene (PE) backsheet (25.4 μm (0.001”) DH-284 PE Microflex® embossed non-breathable film (purchased by Berry Global Group Inc.), commercially available from Clopay Plastic Products Co. Inc., using a Nordson CF® controlled fiberization nozzle at an applicable temperature range of 140°C to 170°C, at a density of 3 g / m². 2 The coating was applied at a rate of (gsm) and a line speed of 244 m (800 ft) / min. After coating the PE backsheet with molten adhesive, the backsheet was laminated onto nonwoven fibers (UNIPRO 45, commercially available from Midwest Filtration LLC) and wound onto a roll.

[0075] The formulations in Tables 11-13 were bonded and prepared as follows. Each HMA formulation was applied in molten form to three LYCRA® 470 dtex strands (pre-stretched to 300%) using a Nordson Allegro® nozzle at an application temperature in the range of 160°C to 180°C, a coating rate of 50 mg / strand / meter, and a line speed of 152 m (500 ft) / min. These strands were then laminated between nonwoven fibers (UNIPRO 45) and a PE backsheet (Clopay's 25.4 μm (0.001”) DH-284 PE Microflex®).

[0076] Preparation process of HMA formulations shown in Tables 14 and 15. The HMA formulation was prepared by preheating a tackifier, oil, antioxidant, and other additives to 177°C. All polymer components were slowly added to the molten mixture of tackifier, oil, antioxidant, and other additives in a 177°C heated mantle. These components were blended by hand using a spatula until all polymer pellets had melted and the mixture was homogeneous. The components were stirred for a further 10 minutes. The resulting adhesive mixture was removed from the heated mantle and poured onto release paper. After the adhesive mixture solidified, it was cut into test pieces.

[0077] Test Procedures for Characteristics in Tables 1-6 MFR was measured according to ASTM D1238, Brookfield viscosity according to ASTM D3236, and flexural modulus according to ASTM D790. The molecular weight distribution and moments (Mw, Mn, Mw / Mn) were measured using high-temperature gel permeation chromatography (Polymer Char GPC-IR) equipped with a multiple-channel band filter based on an infrared detector IR5, an 18-angle light scattering detector, and a viscometer. Polymer separation was achieved using three Agilent Plgel 10 μm Mixed-B LS columns. Detailed analytical principles and methods for molecular weight determination are described in paragraphs

[0044] to

[0051] of PCT Publication WO2019 / 246069A1, the contents of which are incorporated herein by reference (note that the equation for c referenced in paragraph

[0044] for the concentration I at each point in the chromatogram is c = βI, where β is the mass constant and I is the baseline subtracted IR5 broadband signal intensity (I)). Unless otherwise specified, all molecular weight moments used or described herein are determined according to conventional molecular weight (IR molecular weight) determination methods (for example, as referenced in paragraphs

[0044] to

[0045] of the aforementioned publication), where the equation in paragraph

[0044] uses a=0.695 and K=0.000579(1-0.75Wt), where Wt is the mass fraction of hexane comonomer. Furthermore, the comonomer composition is determined by the ratio of IR5 detector intensities corresponding to CH2 and CH3 channels calibrated with a set of PE and PP homopolymer / copolymer standards whose nominal values ​​are predetermined by NMR or FTIR (giving methyl (CH3 / 1000TC) per 1000 total carbons, as described in paragraph

[0045] of the aforementioned PCT publication). The TREF method was performed as described in Wild, et al., J. Poly. Sci., Poly. Phys. Ed., Vol. 20, pg. 441 (1982) and U.S. Patent No. 5,008,204, the contents of which are incorporated herein by reference.

[0078] DSC data were measured as follows. Non-isothermal DSC was performed using a PerkinElmer DSC 8000 at a ramp rate of 10°C / min between -50°C and 200°C. For samples with a heat of fusion greater than 10 J / g, secondary endothermic fusion was used, but for samples with a heat of fusion less than or equal to 10 J / g, the reported T m and H f The values ​​were obtained from either the primary or secondary fusion endothermic DSC scan. Isothermal DSC was performed using HyperDSC® (PerkinElmer DSC 8500). Samples were held at 200°C for 3 minutes, then cooled to 5°C, 7°C, or 10°C. The crystallization half-time reported in minutes, t 1 / 2 This was evaluated based on the time it took to reach 50% of the total crystallinity. The isotactic (mm) triple stereoregularity data is referenced here by EP0629632B1, particularly as described in paragraphs

[0167] to

[0190] . 13 The result was obtained using 13C NMR.

[0079] The polymers produced herein have positional defects based on total propylene monomers. 13 It had defects (determined by 13C NMR). The following three types of defects were defined as locomotor defects: 2,1-erythro; 2,1-threo; and 3,1-isomerization, as well as defects after ethylene insertion. The structure and peak assignments of these defects can be found in L. Resconi, et al., Chem. Rev., Vol. 100, pp. 1253-1345 (2000), the contents of which are incorporated herein by reference. The viscosity of the carpet backing compound was measured using a Rosand Precision Rheometer equipped with a flat-face die measuring 32 mm in length and 2 mm in diameter. The sample was loaded and preheated at 204°C for 1 minute. The following shear rate was used for measurement: 50 seconds -1 ;80 seconds -1 ;130 seconds -1 ;200 seconds -1 ;250 seconds -1 ;300 seconds -1;432 seconds -1 ; and 730 seconds -1 . 200 seconds -1 and 300 seconds -1 The viscosity values ​​(Pa-s) were recorded in Table 6. Augmented force measurements were performed using a TA Instruments ARES-G2 rheometer. Sample strips with a thickness of 1 mm, a width of 13 mm, and a length of 38 mm were prepared using a compression molding press. Each sample was tested under fixed strain while varying the temperature at a fixed ramp rate of 2°C / min. As a result, the sample elongation or buckling observed in the measured axial force or normal force was reported as a function of temperature and time. The maximum axial force and the axial force at 40°C were calculated using TA Instruments TRIOS software.

[0080] Tables 7-15: Test Procedures for HMA Characteristics Brookfield viscosity was measured according to ASTM D3236. The softening point, the temperature at which the substance flows, was measured according to ASTM E-28. PAFT and SAFT were measured according to ASTM D-4498. Aromaticity was determined by NMR spectroscopy and measured in mole percent of aromatic protons. Peeling or peeling strength is a measure of the average force required to separate two bonded substances and was tested in T-peel mode at 30 cm (12 inches) / min using a slip / peel tester from IMASS Inc., as determined according to ASTM D-903. Fiber tearing represents the bonding strength of the adhesive to the substrate and was measured at 25°C, 4°C, and -18°C. Fiber tearing is a visual measurement of the amount of paper substrate fibers adhering to the adhesive after the substrate has been torn. 100% fiber tearing means that the adhesive is stronger than the substrate and 100% of the adhesive is covered within the substrate fibers. 0% fiber tearing means that the adhesive does not bond to the substrate at all and simply falls off the substrate. Fiber tearing was determined by bonding the substrate to HMA. One drop of molten adhesive (180°C) was placed on the first substrate using a dropper. The second substrate was placed on top of the HMA, and a 500g weight was placed on top of the second substrate for uniform application. The HMA was then cooled at the reference temperature for at least 1 hour. The substrate was then torn, and the HMA was examined for fiber tearing.

[0081] The set time is the minimum holding time required to build a bond strength that requires a force of more than 10 kg to break the bond. The set time was measured by dropping molten adhesive (180°C) onto the first substrate using a dropper, and then bonding the substrate with HMA. A second substrate was placed on top of the adhesive, and a 500 g weight was placed on top of the second substrate for uniform application. After predetermined time intervals, the second substrate was removed and examined for fiber tearing. If no fiber tearing was observed, a longer time interval was tried. This cycle was continued until fiber tearing was found. The length of this time was reported as the set time.

[0082] List of embodiments This disclosure may further include any one or more of the following non-limiting embodiments. 1. A polymer blend composition comprising: a main polymer fraction containing propylene-derived units and at least one other comonomer-derived units, having a Mw of about 100,000 to about 300,000 and a melt flow rate (MFR) of about 0.1 g / 10 min to about 70.0 g / 10 min according to ASTM D1238; and a minor polymer fraction containing propylene-derived units and at least one other comonomer-derived units, having a Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 50,000 cP according to ASTM D-3236 (190°C), wherein the amount of at least one other polyolefin comonomer in the minor polymer fraction is at least 7 wt% less than the amount of at least one other polyolefin comonomer in the main polymer fraction.

[0083] 2. The polymer blend composition according to Embodiment 1, comprising a main polymer fraction of approximately 60 wt% to approximately 95 wt% and a minor polymer fraction of approximately 5 wt% to approximately 40 wt%. 3. The polymer blend composition according to Embodiment 1 or 2, wherein the main polymer fraction contains at least 10 wt% to about 30 wt% of units derived from at least one other comonomer, and the minor polymer fraction contains at least 2 wt% to about 8 wt% of units derived from at least one other comonomer. 4. A polymer blend composition according to any one of Embodiments 1 to 3, wherein at least one other comonomer-derived unit comprises an ethylene-derived unit, a C4-C10α-olefin, or a combination thereof. 5. A polymer blend composition according to any one of Embodiments 1 to 4, wherein, when subjected to a temperature-induced elution fractionation method, the main polymer fraction is soluble in a hydrocarbon solvent at -15°C, and the minor polymer fraction is insoluble in a hydrocarbon solvent at -15°C. 6. A polymer blend composition according to any one of Embodiments 1 to 5, wherein the composition has a broad or bimodal molecular weight distribution of about 2.7 to about 5.0. 7. A polymer blend composition according to any one of Embodiments 1 to 6, wherein the composition has an MFR of about 80 g / 10 min to about 400 g / 10 min according to ASTM D1238. 8. A polymer blend composition according to any one of Embodiments 1 to 7, wherein the composition has a broad orthogonal comonomer distribution (CD), and the CD gradient of the composition is less than the CD gradient of the composition (CD 50). 9. A polymer blend composition according to any one of Embodiments 1 to 8, wherein the triplicate stereoregularity of the main polymer fraction is greater than or equal to the triplicate stereoregularity of the minor polymer fraction. 10. The polymer blend composition according to Embodiments 1 to 9, wherein the composition has an isothermal crystallization half-life of about 0.3 minutes to about 3.0 minutes at 5°C. 11. A polymer blend composition according to any one of Embodiments 1 to 10, wherein the main polymer fraction has a heat of fusion of about 10 J / g or less.

[0084] 12. A carpet backing sheet or meltblown fiber comprising the polymer blend composition described in Embodiment 1. 13. A hot melt adhesive composition comprising a polymer blend composition comprising: a main polymer fraction containing propylene-derived units and at least one other comonomer-derived units, having a Mw of about 100,000 to about 300,000 and a melt flow rate of about 0.1 g / 10 min to about 70.0 g / 10 min according to ASTM D1238; and a small polymer fraction containing propylene-derived units and at least one other comonomer-derived units, having a Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 50,000 cP according to ASTM D-3236 (190°C), wherein the amount of at least one other polyolefin comonomer in the small polymer fraction is at least 7 wt% less than the amount of at least one other polyolefin comonomer in the main polymer fraction. 14. The hot melt adhesive composition according to Embodiment 13, wherein the amount of polymer blend composition in the hot melt adhesive composition is about 1 wt% to about 40 wt%. 15. The hot melt adhesive composition according to Embodiment 13 or 14, further comprising about 10 wt% to about 70 wt% of a tackifier, the tackifier having a softening point of about 50°C to about 150°C and 0% to about 15% aromaticity. 16. A hot melt adhesive composition according to any one of embodiments 13 to 15, further comprising 0 wt% to about 30 wt% of wax and further comprising 0 wt% to about 30 wt% of oil. 17. A hot melt adhesive composition according to any one of embodiments 13 to 16, further comprising 0 wt% to about 75 wt% amorphous poly-αolefin, further comprising 0 wt% to about 15 wt% linear α-olefin, and further comprising 0 wt% to about 40 wt% ethylene-vinyl acetate.

[0085] 18. A process for producing a polymer blend composition, comprising the step of combining a main polymer fraction containing propylene-derived units and at least one other comonomer-derived units with a smaller polymer fraction containing propylene-derived units and at least one other comonomer-derived units to form a polymer blend composition, wherein the main polymer fraction has a Mw of about 100,000 to about 300,000 and an MFR of about 0.1 g / 10 min to about 70.0 g / 10 min according to ASTM D1238, and the smaller polymer fraction has a Mw of about 5,000 to about 60,000 and a Brookfield viscosity of about 500 cP to about 50,000 cP according to ASTM D-3236 (190°C), and the amount of at least one other comonomer-derived units in the smaller polymer fraction is at least 7 wt% less than the amount of at least one other comonomer-derived units in the main polymer fraction.

[0086] 19. The process according to Embodiment 18, further comprising, before the combination step, the steps of producing a main polymer fraction in a first reactor system and producing a minor polymer fraction in a second reactor system parallel to the first reactor system. 20. The process according to Embodiment 18 or 19, wherein the polymer blend composition comprises a main polymer fraction of about 60 wt% to about 95 wt% and a minor polymer fraction of about 5 wt% to about 35 wt%, the main polymer fraction comprising about 10 wt% to about 30 wt% of at least one other comonomer-derived unit and the minor polymer fraction comprising about 2 wt% to about 8 wt% of at least one other comonomer-derived unit. 21. The process according to any one of Embodiments 18 to 20, wherein at least one other polyolefin comonomer comprises ethylene, C4-C10α-olefin, or a combination thereof. 22. The process according to any one of Embodiments 18 to 21, wherein, when subjected to a temperature-induced elution fractionation method, the main polymer fraction is soluble in a hydrocarbon solvent at -15°C, and the minor polymer fraction is insoluble in a hydrocarbon solvent at -15°C. 23. The process according to any one of Embodiments 18 to 22, wherein the polymer blend composition has a broad or bimodal molecular weight distribution of about 2.7 to about 5.0 and an MFR of about 80 g / 10 min to about 400 g / 10 min according to ASTM D1238. 24. The process according to any one of Embodiments 18 to 23, wherein the polymer blend composition has a broad orthogonal comonomer distribution (CD), and the CD gradient 90 of the polymer blend composition is smaller than the CD gradient 50 of the polymer blend composition. 25. The process according to any one of Embodiments 18 to 24, wherein the triplicate stereoregularity of the main polymer fraction is greater than or equal to the triplicate stereoregularity of the minor polymer fraction, the polymer blend composition has an isothermal crystallization half-life of about 0.3 minutes to about 3.0 minutes at 5°C, and the main polymer fraction has a heat of fusion of about 10 J / g or less.

[0087] Specific embodiments and features have been described using a series of upper and lower bounds. Unless otherwise indicated, it should be understood that ranges are intended to include any combination of any two values, e.g., any combination of any lower and upper bound, any combination of any two lower bounds, and / or any combination of any two upper bounds. Specific lower, upper, and range limits appear in one or more of the following claims. All values ​​are indicated as "about" or "approximately," taking into account experimental errors and variations that a person skilled in the art would anticipate. Various terms have been defined above. Unless a term used in a claim is defined above, the broadest definition given to that term by a person skilled in the art should be given, as reflected in at least one publication or issued patent. Furthermore, all patents, test procedures, and other documents referenced in this application are invoked by reference in full to the extent that such disclosure is not inconsistent with this application, and are invoked for all rights in which such invocation is permitted. The above description relates to embodiments of the present invention, but it is possible to devise other embodiments and further embodiments of the present invention without departing from the basic scope of the present invention, and the scope of the present invention is defined by the following claims.

Claims

1. A polymer blend composition comprising: a main polymer fraction containing propylene-derived units and at least one other comonomer-derived units, having a melt flow rate (MFR) of 0.1 g / 10 min to 70.0 g / 10 min according to ASTM D1238; and a minor polymer fraction containing propylene-derived units and at least one other comonomer-derived units, having a Brookfield viscosity of 500 cP to 50,000 cP according to ASTM D-3236 (190°C), wherein the polymer blend composition has a bimodal molecular weight distribution of 2.7 to 5.0, and the amount of at least one other polyolefin comonomer in the minor polymer fraction is at least 7 wt% less than the amount of at least one other polyolefin comonomer in the main polymer fraction.

2. The polymer blend composition according to claim 1, comprising 60 wt% to 95 wt% of the main polymer fraction and 5 wt% to 40 wt% of the minor polymer fraction.

3. The polymer blend composition according to claim 1, wherein the main polymer fraction comprises 10 wt% to 30 wt% of at least one other comonomer-derived units, and the minor polymer fraction comprises 2 wt% to 8 wt% of at least one other comonomer-derived units.

4. The polymer blend composition according to claim 1, wherein the at least one other comonomer-derived unit in the main polymer fraction and the minor polymer fraction comprises an ethylene-derived unit, a C4-C10α-olefin, or a combination thereof.

5. The polymer blend composition according to claim 1, wherein, when subjected to a temperature-induced elution fractionation method, the main polymer fraction is soluble in a hydrocarbon solvent at -15°C, and the minor polymer fraction is insoluble in the hydrocarbon solvent at -15°C.

6. The polymer blend composition according to claim 1, wherein the composition has an MFR of 80 g / 10 min to 400 g / 10 min according to ASTM D1238.

7. The polymer blend composition according to claim 1, wherein the composition has a broad orthogonal comonomer distribution (CD), and the CD gradient 90 of the composition is smaller than the CD gradient 50 of the composition.

8. The polymer blend composition according to claim 1, wherein the triplicate stereoregularity of the main polymer fraction is greater than or equal to the triplicate stereoregularity of the minor polymer fraction.

9. The polymer blend composition according to claim 1, wherein the composition has an isothermal crystallization half-life of 0.3 minutes to 3.0 minutes at 5°C.

10. The polymer blend composition according to claim 1, wherein the main polymer fraction has a heat of fusion of 10 J / g or less.

11. A carpet backing sheet or meltblown fiber comprising the polymer blend composition described in claim 1.

12. The polymer blend composition according to claim 1, wherein the amount of at least one other polyolefin comonomer in the small polymer fraction is at least 9 wt% less than the amount of at least one other polyolefin comonomer in the main polymer fraction.

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