Polymer blends with increased temperature resistance

Abstract

Embodiments of the polymer blend can include a first polymer composition and a second polymer composition. The first polymer composition can include a polyolefin having a thermal transition temperature of at least 100°C and a graftable monomer having at least one acid or anhydride functional group grafted onto the polyolefin. The second polymer composition can include an E / X / Y ethylene interpolymer, where E is an ethylene monomer and comprises greater than 50 wt% of the interpolymer, X is an α,β-unsaturated C3-C8 carboxylic acid and comprises greater than 0 to 25 wt% of the interpolymer, and Y is an optional comonomer comprising a C1-C8 alkyl acrylate.

Description

Technical Field

[0001] This specification generally relates to polymer blends comprising acid copolymers, ionomers, and combinations thereof, and more specifically to polymer blends having enhanced temperature resistance. Background Technology

[0002] Polymer blends containing acid copolymers and / or ionomers are commonly used materials in a variety of applications because they possess desired mechanical properties (e.g., notched Izod impact strength), optical properties, or abrasion resistance. For example, these blends can be used in extruded articles such as films, foams, and molded articles. However, these polymer blends may have a useful service temperature below 100°C, making them unsuitable for certain applications where the operating temperature may approach or exceed 100°C. Therefore, there remains a continuous need for polymer blends with increased temperature resistance and desired impact strength. Summary of the Invention

[0003] The embodiments disclosed herein meet the need for polymer blends with increased temperature resistance and desired impact strength.

[0004] According to one embodiment, the polymer blend may include a first polymer composition and a second polymer composition. The first polymer component may include a polyolefin having a heat transition temperature of at least 100°C (defined as a temperature below the temperature at which the storage modulus, measured using dynamic mechanical thermal analysis (DMTA), is >10 MPa at 10 rad / s) and a graftable monomer grafted onto the polyolefin containing at least one acid or anhydride functional group. The second polymer composition may include an E / X / Y ethylene interpolymer, wherein E is an ethylene monomer and constitutes more than 50% by weight of the interpolymer, X is an α,β-unsaturated C3-C8 carboxylic acid and constitutes more than 0 to 25% by weight of the interpolymer, and Y is an optional comonomer comprising C1-C8 alkyl acrylates.

[0005] According to another embodiment, the ionomer composition may include a polymer blend, wherein the first polymer composition, the second polymer composition, or both are at least partially neutralized by a metal salt.

[0006] According to yet another embodiment, a method for preparing an ionomer composition may include blending a first polymer composition and a second polymer composition and neutralizing the first polymer composition and the second polymer composition. The first polymer composition, the second polymer composition, or both may be neutralized by a metal salt before or after blending.

[0007] Further features and advantages will be set forth in the following detailed description, and in part will be apparent to those skilled in the art from those description or will be recognized by practice of the embodiments described herein (including the following detailed description and claims).

[0008] It should be understood that both the foregoing general description and the following detailed description describe various implementation schemes and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. Detailed Implementation

[0009] Specific embodiments of this application will now be described. However, this disclosure may be implemented in various forms and should not be construed as limiting it to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art.

[0010] definition

[0011] The term "polymer" refers to a polymeric compound prepared by polymerizing monomers (whether of the same or different types). Therefore, the general term polymer encompasses the term "homopolymer," which is typically used to refer to polymers prepared from only one type of monomer, and the term "copolymer," which refers to polymers prepared from two or more different monomers. As used herein, the term "interpolymer" refers to a polymer prepared by polymerizing at least two different types of monomers. Therefore, the general term interpolymer includes copolymers and polymers prepared from more than two different types of monomers, such as terpolymers.

[0012] As used herein, "polyolefin" refers to a compound made of one or more materials having the formula C n H 2n Any polymer prepared from olefins. Some ethylene-based polymers or propylene-based polymers as defined below can be polyolefins; however, ethylene-based polymers and propylene-based polymers encompass copolymerization with polar comonomers.

[0013] "Polyethylene" or "ethylene-based polymer" should mean a polymer comprising more than 50% by weight of units derived from ethylene monomers. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Comonomers may include olefin comonomers and polar comonomers. Common forms of polyethylene known in the art include low-density polyethylene (LDPE); linear low-density polyethylene (LLDPE); ultra-low-density polyethylene (ULDPE); very low-density polyethylene (VLDPE); single-point catalytic linear low-density polyethylene comprising both linear low-density resin and substantially linear low-density resin (m-LLDPE); medium-density polyethylene (MDPE); and high-density polyethylene (HDPE).

[0014] The term "LDPE" can also be referred to as "high-pressure ethylene polymer" or "highly branched polyethylene" and is defined as meaning a polymer that has been partially or fully homopolymerized or copolymerized in an autoclave or tubular reactor at pressures above 14,500 psi (100 MPa) using a free radical initiator (such as a peroxide) (see, for example, US 4,599,392, which is incorporated herein by reference). LDPE resins typically have a density in the range of 0.916 g / cc to 0.935 g / cc.

[0015] The term "LLDPE" includes resins prepared using Ziegler-Natta catalyst systems, as well as resins prepared using mono-site catalysts, including but not limited to bismetallocene catalysts (sometimes referred to as "m-LLDPE") and geometry-restricted catalysts; and resins prepared using post-metallocene and molecular catalysts. LLDPE comprises linear, substantially linear, or heterogeneous polyethylene copolymers or homopolymers. Compared to LDPE, LLDPE comprises fewer long-chain branched components and consists of substantially linear ethylene polymers, further defined in U.S. Patents 5,272,236, 5,278,272, 5,582,923, and 5,733,155; homogeneous branched linear ethylene polymer compositions, such as those in U.S. Patent No. 3,645,992; multiphase branched ethylene polymers, such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698; and / or blends thereof (such as those disclosed in U.S. 3,914,342 or U.S. 5,854,045). LLDPE resins can be prepared via gas-phase, solution-phase, or slurry polymerization, or any combination thereof, using any type of reactor or reactor configuration known in the art.

[0016] The term "MDPE" refers to polyethylene with a density of 0.926 to 0.940 g / cc. MDPE is typically prepared using chromium or Ziegler-Natta catalysts or using single-point catalysts (including, but not limited to, bis-metallocene catalysts and catalysts with defined geometries).

[0017] The term "HDPE" refers to polyethylene with a density greater than about 0.940 g / cc, which is typically prepared using Ziegler-Natta catalysts, chromium catalysts, or single-point catalysts (including, but not limited to, bis-crenocero catalysts and confined geometry catalysts).

[0018] As used herein, the terms "propylene-based polymer" or "polypropylene" refer to polymers in polymeric form, meaning polymers comprising more than 50% by weight of units derived from propylene monomers. This includes propylene homopolymers, random copolymers of polypropylene, impact copolymers of polypropylene, propylene / α-olefin interpolymers, and propylene / α-olefin copolymers. Comonomers may include olefin comonomers and polar comonomers.

[0019] As used in this disclosure, the terms "blend" or "polymer blend" refer to a mixture of two or more polymers. Blends may be miscible or immiscible (not phase-separated at the molecular level). Blends may or may not be phase-separated. Blends may or may not contain one or more structural domain configurations, as determined by transmission electron spectroscopy, light scattering, X-ray scattering, and other methods known in the art. Blends can be prepared by physically mixing two or more polymers at a macroscopic level (e.g., melt blending or compounding) or a microscopic level (e.g., simultaneous formation within the same reactor). Blends can be prepared by solution blending in a molten phase or using a common solvent.

[0020] As used in this disclosure, the term "ionomer" refers to a polymer comprising both electrically neutral repeating units and ionized units covalently bonded to the polymer backbone as side-group portions.

[0021] As used herein, “graftable monomer” refers to a molecule that is attached to a polymer as a side chain (e.g., chemically bonded) but is not polymerized or copolymerized as part of the polymer backbone.

[0022] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not such components, steps, or procedures are specifically disclosed. For the avoidance of any doubt, unless stated to the contrary, all compositions claimed using the term "comprising" may include any additional additives, adjuvants, or compounds, whether in polymeric or other forms. In contrast, the term "substantially composed of" excludes any other components, steps, or procedures from any subsequently listed scope, except those that are not essential for operability. The term "composed of" excludes any ingredients, steps, or procedures not specifically described or listed.

[0023] The polymer blends disclosed herein may include a first polymer and a second polymer. It is contemplated that the polymer blends of this disclosure may include any number of additional polymers, such as a third, fourth, fifth, or sixth polymer. Those skilled in the art will understand that the polymer blends of this disclosure can be prepared using any conventional or yet-to-be-developed methods or techniques.

[0024] The first polymer composition of the polymer blends disclosed herein may include a polyolefin having a heat transition temperature of at least 100°C. As used herein, the heat transition temperature may be defined as a temperature below which the storage modulus, as measured using dynamic mechanical thermal analysis (DMTA), is >10 MPa at 10 rad / s. In some embodiments, the heat transition temperature of the polyolefin may be at least 105°C, for example at least 110°C, at least 115°C, at least 120°C, or at least 125°C.

[0025] As previously stated, the polyolefin of the first polymer composition of the polymer blend of the present disclosure may comprise an ethylene-based polymer or a propylene-based polymer.

[0026] In embodiments where the polyolefin of the first polymer composition of the polymer blend of this disclosure may comprise an ethylene-based polymer, the ethylene-based polymer may include high-density polyethylene (HDPE). In one or more embodiments, the HDPE may have a density of 0.940 g / cc to 0.980 g / cc, or 0.945 g / cc to 0.965 g / cc, or 0.945 g / cc to 0.955 g / cc. In alternative embodiments, the ethylene-based polymer may comprise linear low-density polyethylene (LLDPE) or low-density polyethylene (LDPE).

[0027] The polyolefin of the first polymer composition of the polymer blend disclosed herein may have a melt index (I2) of 0.5 g / 10 min to 300 g / 10 min. For example, the polyolefin of the first polymer composition of the polymer blend of this disclosure may have the following melt index (I2): 0.5 g / 10 min to 275 g / 10 min, such as 0.5 g / 10 min to 250 g / 10 min, 0.5 g / 10 min to 225 g / 10 min, 0.5 g / 10 min to 200 g / 10 min, 0.5 g / 10 min to 175 g / 10 min, such as 0.5 g / 10 min to 150 g / 10 min, 0.5 g / 10 min to 125 g / 10 min, 0.5 g / 10 min to 100 g / 10 min, 0.5 g / 10 min to 75 g / 10 min, such as 0.5 g / 10 min to 50 g / 10 min, 0.5 g / 10 min to 25 g / 10 min, 0.5 g / 10 min to 1 0g / 10min, 2.5g / 10min to 300g / 10min, 2.5g / 10min to 275g / 10min, such as 2.5g / 10min to 250g / 10min, 2.5g / 10min to 225g / 10min, 2.5g / 10min to 200g / 10min, 2.5g / 10min to 175g / 10min, such as 2.5g / 10min to 150g / 10min, 2.5g / 10min to 125g / 10min, 2.5g / 10min to 100g / 10min, 2.5g / 10min to 75g / 10min, such as 2.5g / 10min to 50g / 10min, 2.5g / 10min to 25g / 10min, 2.5g / 10min to 10g / 10min.The polyolefin of the first polymer composition of the polymer blend may have the following melt index (I2): 0.5 g / 10 min to 60 g / 10 min, 0.5 g / 10 min to 50 g / 10 min, 0.5 g / 10 min to 40 g / 10 min, 0.5 g / 10 min to 30 g / 10 min, 0.5 g / 10 min to 20 g / 10 min, 0.5 g / 10 min to 10 g / 10 min, 1.0 g / 10 min to 60 g / 10 min, 1.0 g / 10 min to 50 g / 10 min, 1.0 g / 10min to 40g / 10min, 1.0g / 10min to 30g / 10min, 1.0g / 10min to 20g / 10min, 1.0g / 10min to 10g / 10min, 1.5g / 10min to 60g / 10min, 1.5g / 10min to 50g / 10min, 1.5g / 10min to 40g / 10min, 1.5g / 10min to 30g / 10min, 1.5g / 10min to 20g / 10min or 1.5g / 10min to 10g / 10min.

[0028] The first polymer composition of the polymer blends disclosed herein comprises a graftable monomer grafted onto a polyolefin, the graftable monomer containing at least one acid or anhydride functional group. Of particular interest are graftable monomers having both a vinyl unsaturated group and an acid or anhydride group. The graftable monomer can be grafted onto the polyolefin using a radical-generating initiator. The graft polymerization reaction can be carried out in the presence of a radical-generating agent such as an organic peroxide (e.g., an alkyl peroxide) or an azo compound. Ultrasound or ultraviolet radiation, or any high-energy radiation, can be used to generate radicals. Alternatively or alternatively, the graftable monomer can be thermally grafted onto the polyolefin. Thermal grafting can refer to grafting performed using an extruder or a high-shear mixer using shear and heat. The grafting level of the graftable monomer can be from 0.1 wt% to 20 wt% of the combined weight of the polyolefin and the graftable monomer. In embodiments, the grafting level of the graftable monomer can be from 0.3 wt% to 10 wt% or from 0.5 wt% to 8 wt%. Furthermore, graft polymerization methods can also utilize reactive auxiliaries that facilitate the grafting of polyolefins and graftable monomers. Various reactive auxiliaries with high levels of unsaturation are considered suitable, such as allyl, vinyl, or acrylate reactive auxiliaries.

[0029] Graftable monomers may include acrylic acid, methacrylic acid, ethylacrylic acid, itaconic acid, maleic acid, fumaric acid, monoesters of the dicarboxylic acids, such as methyl maleate, methyl fumarate, ethyl fumarate, maleic anhydride, or combinations thereof. In specific embodiments, the graftable monomer may include acrylic acid or methacrylic acid. In embodiments, the graftable monomer may comprise, consist of, or substantially consist of, at least one of acrylic acid, methacrylic acid, or both grafted onto a polyolefin.

[0030] The second polymer composition of the polymer blends disclosed herein may include an E / X / Y ethylene interpolymer. "E" in the E / X / Y ethylene interpolymer may be an ethylene monomer. The ethylene monomer may constitute more than 50% by weight of the interpolymer. "X" in the E / X / Y ethylene interpolymer may be an α,β-unsaturated C3-C8 carboxylic acid. The α,β-unsaturated C3-C8 carboxylic acid may constitute more than 0 to 25% by weight of the ethylene interpolymer or 1% to 10% by weight of the ethylene interpolymer. Examples of "X" may include acrylic acid, methacrylic acid, ethylacrylic acid, itaconic acid, maleic acid, fumaric acid, monoesters of said dicarboxylic acids, such as methyl maleate, methyl fumarate, ethyl fumarate, and maleic anhydride. In a specific embodiment, "X" includes acrylic acid or methacrylic acid.

[0031] The "Y" in E / X / Y ethylene interpolymers can be any comonomer containing C1-C8 alkyl acrylates. These may include, but are not limited to, ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, or combinations thereof.

[0032] The second polymer composition of the polymer blend disclosed herein may have a density of 0.910 g / cc to 0.990 g / cc, or 0.920 g / cc to 0.980 g / cc, or 0.925 g / cc to 0.975 g / cc.

[0033] The second polymer composition of the polymer blends disclosed herein may have a melt index (I2) of 0.5 g / 10 min to 500 g / 10 min. For example, the second polymer composition of the polymer blends disclosed herein may have the following melt index (I2): 0.5 g / 10 min to 475 g / 10 min, such as 0.5 g / 10 min to 450 g / 10 min, 0.5 g / 10 min to 425 g / 10 min, 0.5 g / 10 min to 400 g / 10 min, 0.5 g / 10 min to 375 g / 10 min, such as 0.5 g / 10 min to 350 g / 10 min, 0.5 g / 10 min to 325 g / 10 min, 0.5 g / 10 min to 300 g / 10 min, 0.5 g / 10 min... Up to 275g / 10min, such as 0.5g / 10min to 250g / 10min, 0.5g / 10min to 225g / 10min, 0.5g / 10min to 200g / 10min, 0.5g / 10min to 175g / 10min, such as 0.5g / 10min to 150g / 10min, 0.5g / 10min to 125g / 10min, 0.5g / 10min to 100g / 10min, 0.5g / 10min to 75g / 10min, such as 0.5g / 10min to 50g / 10min, 0.5g / 10min to 275g / 10min, such as 0.5g / 10min to 250g / 10min, 0.5g / 10min to 225g / 10min, 0.5g / 10min to 100g / 10min, 0.5g / 10min to 75g / 10min, such as 0.5g / 10min to 50g / 10min, 0.5g / 10min to 275g / 10min, such as ... 5g / 10min, 0.5g / 10min to 10g / 10min, 2.5g / 10min to 450g / 10min, 2.5g / 10min to 425g / 10min, 2.5g / 10min to 400g / 10min, 2.5g / 10min to 375g / 10min, such as 2.5g / 10min to 350g / 10min, 2.5g / 10min to 325g / 10min, 2.5g / 10min to 300g / 10min, 2.5g / 10min to 275g / 10min, such as 2.5g / 10min to 250g / 10 min, 2.5 g / 10 min to 225 g / 10 min, 2.5 g / 10 min to 200 g / 10 min, 2.5 g / 10 min to 175 g / 10 min, such as 2.5 g / 10 min to 150 g / 10 min, 2.5 g / 10 min to 125 g / 10 min, 2.5 g / 10 min to 100 g / 10 min, 2.5 g / 10 min to 75 g / 10 min, such as 2.5 g / 10 min to 50 g / 10 min, 2.5 g / 10 min to 25 g / 10 min, 2.5 g / 10 min to 10 g / 10 min.The second polymer composition of the polymer blend may have the following melt index (I2): 0.5 g / 10 min to 50 g / 10 min, 0.5 g / 10 min to 40 g / 10 min, 0.5 g / 10 min to 30 g / 10 min, 0.5 g / 10 min to 20 g / 10 min, 0.5 g / 10 min to 10 g / 10 min, 1.0 g / 10 min to 60 g / 10 min, 1.0 g / 10 min to 50 g / 10 min, 1.0 g / 10 min to 40 g / 10 min. min, 1.0g / 10min to 30g / 10min, 1.0g / 10min to 20g / 10min, 1.0g / 10min to 10g / 10min, 1.5g / 10min to 60g / 10min, 1.5g / 10min to 50g / 10min, 1.5g / 10min to 40g / 10min, 1.5g / 10min to 30g / 10min, 1.5g / 10min to 20g / 10min or 1.5g / 10min to 10g / 10min.

[0034] The polymer blends disclosed herein may comprise a first polymer composition and a second polymer composition in a weight ratio ranging from 20 / 80 wt% to 80 / 20 wt%. For example, the polymer blends disclosed herein may comprise a first polymer composition and a second polymer composition in a weight ratio ranging from 25 / 75 wt% to 75 / 25 wt%, such as 30 / 70 wt% to 70 / 30 wt%, 35 / 65 wt% to 65 / 35 wt%, 40 / 60 wt% to 60 / 40 wt%, or 45 / 55 wt% to 55 / 45 wt%.

[0035] The polymer blends of the present invention can also be formed as ionomer compositions. In such embodiments, the first polymer composition, the second polymer composition, or both polymers in the blend are at least partially neutralized by a metal salt used as an ion source. Typical ion sources include sodium hydroxide, sodium carbonate, sodium acetate, zinc oxide, zinc acetate, magnesium hydroxide, and lithium hydroxide. Other ion sources are well known and will be understood by those skilled in the art. In addition to sodium, zinc, magnesium, and lithium ions, other alkali metal or alkaline earth metal cations are also useful and may include potassium, calcium, tin, lead, aluminum, and barium. Combinations of ions may also be used. It is contemplated that the first polymer composition, the second polymer composition, or both polymers in the blend can be at least partially neutralized by a metal salt with or without a catalyst. Catalysts such as water or acetic acid may be used. The polymer blends in the ionomer compositions may have any of the characteristics or compositions previously described in this disclosure regarding polymer blends.

[0036] The expected degree of neutralization may depend on the desired application. As used in this disclosure, "degree of neutralization" may refer to the amount of acidic sites neutralized by the metal salt. The degree of neutralization may be based on the amount of acidic sites on the first polymer composition, the second polymer composition, or both. In embodiments, the degree of neutralization of the first polymer composition, the second polymer composition, or both may be from 15% to 90%. That is, 15% to 90% of the acidic sites of the first polymer composition, the second polymer composition, or both may be neutralized by the metal salt.

[0037] In embodiments, 15% to 90% of the acid sites of the first polymer composition, the second polymer composition, or both can be neutralized by a metal salt, for example, 15% to 80%, 15% to 70%, 15% to 60%, 15% to 50%, 15% to 40%, 15% to 30%, 15% to 20%, 25% to 90%, 25% to 80%, 25% to 70%, 25% to 60%, 25% to 50%, 25% to 40%, 25% to 30%, or 35%. Up to 90%, 35% to 80%, 35% to 70%, 35% to 60%, 35% to 50%, 35% to 40%, 45% to 90%, 45% to 80%, 45% to 70%, 45% to 60%, 45% to 50%, 55% to 90%, 55% to 80%, 55% to 70%, 55% to 60%, 65% to 90%, 65% to 80%, 65% to 70%, 75% to 90%, 75% to 80%, or 85% to 90%.

[0038] The ionomer compositions disclosed herein can be defined by a rheological ratio greater than 10.0. As used herein, "rheological ratio" can refer to a ratio within 0.1 s2 seconds. -1 The shear rate and viscosity measured at 190°C were compared with those measured at 100 s. -1 The ratio of the viscosity measured at 190°C to the viscosity of the polymer. In embodiments, the ionomer composition may have a rheological ratio greater than 10.5, for example greater than 11.0, greater than 11.5, greater than 12.0, greater than 12.5, greater than 13.0, greater than 13.5, greater than 14.0, greater than 14.5, or greater than 15.0. Without being theoretically constrained, a rheological ratio greater than 10.0 is associated with improved processability of the polymer and / or polymer blends.

[0039] The ionomer compositions of this disclosure may have a phase angle of less than 57°, measured using dynamic rheological measurements (e.g., oscillatory shear measurements) at 190°C and a complex modulus G* = 20 kPa. As used in this disclosure, "phase angle" is a measure of the stress-strain relationship, which is a function of the degree to which the ionomer composition responds with respect to the strain input. For Newtonian liquids, the phase angle would be 90 degrees, while for Hookean solids, the phase angle would be 0 degrees. The phase angle of viscoelastic materials (i.e., the polymers, polymer blends, ionomers, or ionomer compositions of this disclosure) lies between these two extreme values. In embodiments, the ionomer compositions may have a phase angle of less than 56°, such as less than 55°, less than 54°, less than 53°, less than 52°, less than 51°, or less than 50°. Again, without being theoretically constrained, a phase angle of less than 57° is associated with improved processability of the polymer and / or polymer blends.

[0040] The polymer blends and ionomer compositions disclosed herein may have a thermal transition temperature greater than 90°C, for example greater than 92°C, greater than 94°C, greater than 96°C, greater than 98°C, greater than 100°C, greater than 102°C, greater than 104°C, greater than 106°C, greater than 108°C, or greater than 110°C, as measured by dynamic mechanical thermal analysis (DMTA), which is explained in detail in the Test Methods section of this disclosure.

[0041] The polymer blends and ionomer compositions disclosed herein may additionally include small amounts of additives, including plasticizers, stabilizers (including viscosity stabilizers and hydrolytic stabilizers), primary and secondary antioxidants, ultraviolet absorbers, antistatic agents, dyes, pigments or other colorants, inorganic fillers, flame retardants, lubricants, reinforcing agents (such as glass fibers and glass sheets), synthetic (e.g., aramid) fibers or pulp, foaming or bubbling agents, processing aids, slip additives, anti-caking agents (such as silica or talc), release agents, tackifying resins, or combinations of two or more of these. Inorganic fillers such as calcium carbonate may also be incorporated into the polymer blends and ionomer compositions.

[0042] These additives may be present in polymer blends and ionomer compositions in amounts ranging from 0.01 wt% to 40 wt%, 0.01 wt% to 25 wt%, 0.01 wt% to 15 wt%, 0.01 wt% to 10 wt%, or 0.01 wt% to 5 wt%. The incorporation of additives can be carried out by any known method, such as by dry blending, by extruding mixtures of various components, by conventional masterbatch techniques, etc.

[0043] A method for preparing the polymer blends of this disclosure may include blending a first polymer composition and a second polymer composition. Similarly, a method for preparing the ionomer compositions of this disclosure may include blending a first polymer composition and a second polymer composition and neutralizing the first polymer composition and the second polymer composition. During the neutralization of the first polymer composition and the second polymer composition, the first polymer composition, the second polymer composition, or both may be neutralized by a metal salt before or after blending.

[0044] The method for preparing the polymer blends or ionomer compositions of this disclosure, i.e., the blending and neutralization steps, can be carried out continuously. In embodiments where the blending and neutralization steps are carried out continuously, an extruder or kneader can be used to blend and neutralize the components. Some examples of continuous equipment that can be used include co-rotating or counter-rotating twin-screw extruders, single-screw extruders, continuous mixers, reciprocating kneaders, and multi-screw extruders. The method for preparing the polymer blends or ionomer compositions of this disclosure can also be carried out batch. In embodiments where the blending and neutralization steps are carried out batch, a batch mixer can be used to blend and neutralize the components. Some examples of batch mixers are twin-roll mills, intermeshing or non-intermeshing internal mixers.

[0045] According to various embodiments, the polymer blends or ionomer compositions of this disclosure can be used to form extruded articles, such as blown or cast films, foams, or molded articles. For example, in embodiments where the polymer blends or ionomer compositions can be used to form foams, the polymer blends or ionomer compositions can be combined with additives for controlling foam properties to form foams of various shapes. In some embodiments, as known to those skilled in the art, the foam can be extruded, for example, from a twin-screw extruder.

[0046] Test methods

[0047] density

[0048] Samples for density measurement were prepared according to ASTM D 1928. The polymer sample was pressed for three minutes at 190°C and 30,000 psi, followed by one minute at 21°C and 207 MPa. Measurements were performed within one hour of sample pressing using ASTM D792, Method B.

[0049] Melt index (I2)

[0050] Melt index or I2 (g / 10 min or dg / min) is measured according to ASTM D 1238, conditions 190°C / 2.16 kg, procedure B.

[0051] Dynamic mechanical spectrum (DMS)

[0052] Small-angle (amplitude) oscillatory shear measurements were performed using a TA instrument (ARES) equipped with a 25 mm parallel plate under nitrogen purging. The experiment was conducted at 190 °C for 0.1 s⁻¹. -1 up to 100s -1 The frequency range was measured. Based on the sample response, the strain amplitude was adjusted to 1% to 3%. The stress response was analyzed based on amplitude and phase, and the storage modulus (G′), loss modulus (G″), complex modulus (G*), dynamic viscosity η*, and phase angle (6) were calculated as functions of frequency. The values ​​were used at 0.1 s. -1 and 100s -1 The rheological ratio was calculated from the shear viscosity ratio at the shear rate. The phase angle θ at the complex modulus G* at 20 kPa was also recorded. The rheological ratio and θ were used as measures of melt elasticity and melt strength. The samples were dried overnight at 70-80°C before testing.

[0053] Dynamic mechanical thermal analysis (DMTA)

[0054] DMTA measurements were performed on an ARES-G2 instrument under nitrogen purging. Samples approximately 3 mm thick were die-cut into rectangular specimens measuring 12.7 mm × 30 mm. Temperature scans were performed in torsion mode from 30 °C to 140 °C in 5 °C increments. A frequency of 10 rad / s was used. The strain amplitude was adjusted (0.1% to 5%) to control the torque response. Storage modulus was measured as a function of temperature, and the temperature at which the storage modulus (G′) dropped below 10 MPa was used as a measure of thermal resistance and termed the thermal transition temperature. Samples were dried at 70 °C–80 °C for 8–10 hours prior to testing.

[0055] neutral level

[0056] The % neutralization level is calculated based on the number of moles of neutralizing agent used in the formulation relative to the number of moles of the present acid (grafted or partially base acid copolymer) and also specifies the valence of the ions.

[0057] The neutralization percentage of an ionomer resin can be readily calculated based on stoichiometry. For example, the ratio of the alkali metal cations in a combination to the acid moiety in a combination of acid copolymers in a molar percentage is the neutralization percentage. Terms such as neutralization percentage can be used interchangeably with terms such as neutralization percentage and degree of neutralization. Various types of acid moieties and various types of cations used for neutralizing acid moieties can be present in polymers or polymer blends. Therefore, the formula for neutralization can be expressed as:

[0058]

[0059] In the above formula, %NA J It is the weight percentage of neutralizing agent J, MWJ It is the molecular weight of neutralizing agent J, % ACID a It is the weight percentage of the acid copolymer or graft a, and MW a This refers to the molecular weight of the acid type. The molecular weight of acrylic acid is 72.06 g / mol, methacrylic acid is 86.09 g / mol, zinc oxide is 81.41 g / mol, and sodium carbonate is 105.99 g / mol. The ∑ symbol represents the sum of the different types of ions in the molecule and the different types of acids in the denominator. Factor J is the product of the valence of the ions and the number of atoms in the molecular formula of neutralizing agent J. For example, in zinc oxide (ZnO), each zinc atom has a divalent valence, and there is one zinc atom in ZnO. Therefore, the factor ZnO is 2. For example, in sodium carbonate (Na₂CO₃), each sodium atom has a monovalent valence, and there are two sodium atoms in Na₂CO₃. Therefore, the factor Na₂CO₃ is also 2.

[0060] The amount of alkaline metal compound that can achieve the target neutralization of the acidic groups in the acid copolymer can be determined by adding an alkaline compound in a stoichiometric amount to neutralize the target amount of the acidic group in the acid copolymer.

[0061] Izod impact strength

[0062] Notched Izod impact strength was tested on samples cut from injection-molded sheets according to ASTM D256. Tests were conducted at three different temperatures: 23°C, 0°C, and -23°C.

[0063] Example

[0064] The implementation scheme is further illustrated by the following examples.

[0065] The following examples were prepared using various components. Table 1 lists the trade names and properties of these components. The materials used, their properties, and their suppliers are summarized in the table below. Zinc oxide (ZnO) and sodium carbonate (Na2CO3) masterbatches were prepared in a twin-screw extruder in granular form for ease of handling and feeding in subsequent steps.

[0066] Table 1. Components and Properties of Examples

[0067]

[0068]

[0069] 1 Technical data sheet from the manufacturer

[0070] 2 At 190℃ and 2.16kg

[0071] 3 77HSA grade zinc from the United States

[0072] 4 Anhydrous sodium acetate grade from Brenntag, North America

[0073] Comparative Example 1 - Polymer Blend

[0074] In Comparative Example 1, polymer blends comprising HDPE without grafted monomers were prepared. Table 2 provides the composition of these comparative polymer blends and the resulting properties.

[0075] The components of the examples in Table 2 were mixed in a twin-screw extruder. Specifically, polymers, polymer blends, ionomers, and ionomer blends were prepared at a ratio of 60 L / D on a Coperion ZSK 26 co-rotating twin-screw extruder (TSE). The motor was rated at 40 hp and the maximum screw speed was 1200 RPM. The feed rate was 8 lbs / h and the screw speed used was 250 rpm. The barrel temperature was maintained at 180°C–200°C. In some experiments, deionized water was injected using a high-pressure piston pump. A vacuum of 20 inches of mercury was evacuated after mixing and before the die to remove byproducts (water) during neutralization. The compounded material was extruded through a two-hole die into a 10-foot-long cooling water bath. The strands were then passed through an air knife to remove excess water and cut into pellets using a strand cutter.

[0076] The compounded granules were injection molded into sheets. Specifically, a Toyo Si-90 injection molding machine was used to form 4″×6″×0.125″ sheets. All materials were dried at 70°C for 4 hours prior to molding. A barrel temperature of 170°C–210°C was used. An injection size of 125 mm, an injection speed of 75 mm / s, and a plasticizing screw speed of 75–100 rpm were used. The injection-molded sheets were then used to cut specimens for DMS and DMTA testing.

[0077] As shown, the blends in Table 2 with DMDA 8007 (HDPE without grafted monomers) achieved a thermal transition temperature above 100°C for DMTA, but did not achieve a rheology ratio above 10 or a phase angle below 57°, which are properties indicating improved processability.

[0078] Table 2. Polymer blend compositions and properties

[0079]

[0080]

[0081] Example 2 - Ionomer compositions with enhanced temperature resistance neutralized by zinc salts

[0082] In Example 2, other blends were prepared using the same method as in Comparative Example 1. Contrary to Example 1, these first polymer compositions of the polymer blends were grafted with a graftable monomer containing at least one acid or anhydride functional group, and then at least partially neutralized using a zinc salt. Table 3 provides the compositions of the various ionomer blends neutralized with zinc salts and their resulting properties. Those skilled in the art will understand that these ionomer blends are not technically ionomers until they are neutralized.

[0083] Table 3 also specifies whether each example or comparative example was prepared using a one-step or two-step method. This corresponds to the above discussion regarding whether the first polymer composition and the second polymer composition are neutralized together or separately. In a one-step preparation method, the first polymer composition and the second polymer composition are first blended together and then neutralized. In a two-step preparation method, the first polymer composition and the second polymer composition are first neutralized, then blended together, and then neutralized once blended.

[0084] Table 3. Ionomer compositions and properties using zinc salts

[0085]

[0086]

[0087] 1 Example 2F is a blend of equal portions of Comparative Example 2B and Comparative Example 2C. In Example 2F, Comparative Example 2B and Comparative Example 2C were prepared (and neutralized) before being blended together. The values ​​in Table 3 correspond to the final composition of Example 2F.

[0088] 2 Comparative Example 2E is a blend of equal portions of Comparative Example 2B and DMDA 8007. Comparative Example 2E was prepared in the same manner as Example 2F (neutralizing the components before blending).

[0089] Table 3 lists various embodiments of the ionomer compositions with enhanced temperature resistance. Examples 2A-2F provide embodiments comprising an ionomer blend of AA-grafted HDPE (Polybond 1009) at least partially neutralized with zinc salt and a NUCREL™ acid copolymer or both. As shown in Table 3, the degree of neutralization in Examples 2A-2F varies between 29.0% and 50.2%. Examples 2A-2F each exhibit enhanced heat resistance because each example is characterized by a DMTA heat transition temperature greater than 90°C. Furthermore, Examples 2A-2F each have a rheological ratio greater than 10.0 and a phase angle less than 57. In contrast, Comparative Examples 2A-2E, which do not include either AA-grafted HDPE or the acid copolymer, fail to achieve this combination of temperature resistance, rheological ratio, and phase angle.

[0090] Example 3 - Ionomer compositions with enhanced temperature resistance neutralized using sodium salts

[0091] In Example 3, the ionomer composition was prepared using the same method as in Example 2. Compared to Example 2, in Example 3, a sodium salt was used instead of a zinc salt for neutralization. Table 4 provides the composition of the various ionomer compositions neutralized using sodium salts and their resulting properties.

[0092] Similar to Table 3, Table 4 also specifies whether the examples or comparative examples were prepared using a one-step or two-step method.

[0093] Table 4. Ionomer compositions and properties neutralized with sodium salts

[0094]

[0095] Example 3D is a blend of equal portions of Comparative Example 3A and Comparative Example 3C. In Ex. 3D, Comparative Example 3A and Comparative Example 3C were prepared (and neutralized) before being blended together. The values ​​in Table 4 correspond to the final composition of Example 3D.

[0096] Table 4 lists various embodiments of the ionomer compositions with enhanced heat resistance. As shown in Table 4, the degree of neutralization of Examples 3A-3D varies between 46.3% and 49.9%. Examples 3A-3D each have enhanced heat resistance because each example is characterized by a DMTA heat transition temperature greater than 90°C. Furthermore, Examples 3A-3D each have a rheological ratio greater than 10.0 and a phase angle less than 57. In contrast, Comparative Examples 3A-3C do not include either AA-grafted HDPE or the acid copolymer.

[0097] Example 4 - Notched Izod impact strength values ​​from various embodiments of Examples 2 and 3

[0098] Table 5 provides the notched Izod impact strength values ​​for Examples 2 and 3 of the present invention and comparative examples.

[0099] Table 5. Notched Izod Impact Strength

[0100]

[0101] 1 NB refers to the notched Izod impact strength, which is greater than 1300 J / m.

[0102] As shown in Table 5, the examples in Table 5 exhibit significantly higher notched Izod impact strengths than the comparative examples. In fact, many examples exhibit notched Izod impact strengths greater than 1300 J / m to some extent. Conversely, the comparative examples did not exhibit notched Izod impact strengths greater than 60.0. Therefore, these polymer blends of the present invention not only exhibit the increased heat resistance as described above, but also demonstrate improved impact strength.

[0103] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, this specification is intended to cover modifications and variations to the various embodiments described herein, provided that such modifications and variations fall within the scope of the appended claims and their equivalents.

Claims

1. A polymer blend comprising: a first polymer composition comprising: a polyolefin having a thermal transition temperature of at least 100 °C, the thermal transition temperature defined as the temperature lower than the temperature at which the storage modulus measured using dynamic mechanical thermal analysis (DMTA) is > 10 MPa at 10 rad / s, wherein the polyolefin comprises an ethylene-based polymer or a propylene-based polymer, and wherein the ethylene-based polymer includes a high density polyethylene having a density greater than 0.940 g / cc; and a graftable monomer comprising at least one acid or anhydride functional group grafted onto the polyolefin, a second polymer composition comprising an E / X / Y ethylene interpolymer, wherein E is ethylene monomer and comprises greater than 50 wt% of the interpolymer, X is an a,b-unsaturated C3-C8 carboxylic acid and comprises greater than 0 to 25 wt% of the ethylene interpolymer, and Y is an optional comonomer comprising a C1-C8 alkyl acrylate, wherein the graftable monomer includes at least one of acrylic acid, methacrylic acid, or both grafted onto the polyolefin.

2. The polymer blend of claim 1, wherein the a,b-unsaturated C3-C8 carboxylic acid comprises acrylic acid or methacrylic acid.

3. The polymer blend of claim 1, wherein the polyolefin comprises a melt index, I2, of 0.5 g / 10 min to 60 g / 10 min when measured according to ASTM D1238 at 190 °C / 2.16 kg.

4. The polymer blend of claim 1, wherein the weight ratio of the first polymer composition to the second polymer composition is 20 / 80 wt% to 80 / 20 wt%.

5. The polymer blend of claim 1, wherein the first polymer composition, the second polymer composition, or both comprise acrylic acid.

6. The polymer blend of claim 1, wherein the polyolefin has a thermal transition temperature of at least 125 °C.

7. An ionomer composition comprising the polymer blend of claim 1, wherein the first polymer composition, the second polymer composition, or both are at least partially neutralized by a metal salt.

8. The ionomer composition of claim 7, wherein 15% to 90% of the acid sites of the first polymer composition, the second polymer composition, or both are neutralized by the metal salt.

9. The ionomer composition of claim 7, wherein the metal salt comprises one or more salts of zinc, magnesium, lithium, aluminum, or sodium.

10. The ionomer composition of claim 7, wherein the ionomer composition has a rheology ratio greater than 10.0 measured at a test temperature of 190 °C.

11. The ionomer composition of claim 7, wherein the ionomer composition has a phase angle less than 57° measured at a test temperature of 190 °C and a complex modulus of 20 kPa.

12. A method of making the ionomer composition of claim 7, the method comprising: blending the first polymer composition and the second polymer composition; and neutralizing the first polymer composition and the second polymer composition, wherein the first polymer composition, the second polymer composition, or both, are neutralized with a metal salt prior to or after blending.

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