METHOD FOR MAKING A HOMOGENEOUS MIXTURE OF POLYOLEFIN SOLIDS AND AN ORGANIC PEROXIDE

Abstract

A method for making a homogeneous mixture of polyolefin solids and an organic peroxide without melting the polyolefin solids during preparation. The method comprises applying acoustic energy at a frequency of 20 to 100 hertz to a heterogeneous mixture comprising the polyolefin solids and the organic peroxide for a period of time sufficient to substantially intermix the polyolefin solids and the organic peroxide while maintaining the temperature of the heterogeneous mixture below the melting temperature of the polyolefin solids, thereby making the mixture homogeneous without melting the polyolefin solids.

Description

METHOD FOR MAKING A HOMOGENEOUS MIXTURE OF FOLIOLEFIN SOLIDS AND AN ORGANIC PEROXIDE FIELD OF INVENTION Polyolefin blend with additives. BACKGROUND OF THE INVENTION Patent publications and patent applications in the field include US 6,565,784; US 7,188,993 B1; US ​​7,468,404 B2; US 7,695,817 B2; US 8,124,309 B2; US 8,435,714 B2; US 8,680,177 B2; US 8,889,331 B2; US 9,223,236 B2; US 9,593,919 B2; US 9,926,427 B2; US 9,957,360 B2; and US 10,513,625 B2. Non-patent publications in or about the field include Assessment of extrusion-sonication process on flame retardant polypropylene by rheological characterization, by G. Sanchez-Olivares, et al. AIMS Materials Science, 2016; vol. 3, no. 2, pages 620 to 633; and ENHANCED DISPERSION OF PARTICIE ADDITIVE INTO POLYMERS USING TWIN SCREW EXTRUSION WITH ULTRASOUND ASSISTANCE, by K. Tarverdi, et al., SPE ANTEC Anaheim 2017, pages 1058 to 1062. Previous methods of blending polyolefins with additives are based on the mechanical mixing of fluidized melts (e.g., in a twin-screw extruder). This method can be detrimental to organic peroxides, which degrade or decompose. Ref. 331892 rapidly reaches fluidized melt temperatures (e.g., 180° to 220°C for polyethylenes). Instead, after mixing a fluidized melt of a polyolefin with additives other than peroxides, the resulting mixture is granulated at room temperature. The granules are then heated to a soaking temperature and passively soaked with a liquid organic peroxide or a melt of a low-melting-point organic peroxide. The soaking temperature for liquid organic peroxide can be from 30° to 110°C. The solid organic peroxide used in the soaking method can have a melting point of 30° to 100°C, and the soaking temperature is higher than the melting point of the solid organic peroxide at 110°C.For example, dicumyl peroxide melts at 39°C to 41°C, and the soaking temperature can be approximately 50°C to 90°C, typically 60°C to 80°C. In commercial plants, the granules are placed in large containers and soaked with organic peroxide, which takes 10 to 16 hours to fully wet the polyolefin solids with the organic peroxide. BRIEF DESCRIPTION OF THE INVENTION We have discovered a method for making a homogeneous mixture of polyolefin solids and an organic peroxide without melting the polyolefin solids during preparation. cq Lznn / zznz / E / YiAi The method comprises applying acoustic energy at a frequency of 20 to 100 hertz to a heterogeneous mixture comprising polyolefin solids and organic peroxide for a period of time sufficient to substantially intermix the polyolefin solids and organic peroxide while maintaining the temperature of the heterogeneous mixture (and, for that matter, the temperature of the homogeneous mixture made from it) below the melting temperature of the polyolefin solids, thereby making the mixture homogeneous without melting the polyolefin solids. The method achieves complete intermixing of the polyolefin solids and the organic peroxide without mechanically mixing or melting the polyolefin solids, and it does so quickly in relation to a soaking method. DETAILED DESCRIPTION OF THE INVENTION A method for making a homogeneous mixture of polyolefin solids and an organic peroxide without melting the polyolefin solids during preparation. The method comprises applying acoustic energy at a frequency of 20 to 100 hertz to a heterogeneous mixture comprising the polyolefin solids and the organic peroxide for a period of time sufficient to substantially intermix the polyolefin solids and the organic peroxide while maintaining the temperature of the heterogeneous mixture (and, for the case here, the temperature of the homogeneous mixture made therefrom) below the melting temperature of the polyolefin solids, thereby making the mixture homogeneous without melting the polyolefin solids. The method comprises a mixing step consisting essentially of the acoustic energy application step.This means that the method achieves complete intermixing of the polyolefin solids and the organic peroxide without mechanically mixing or melting the polyolefin solids, and it does so quickly in relation to soaking, for example, in less than 10 minutes. Additional aspects of the invention are described below; some are listed below for ease of reference. Aspect 1. A method for making a homogeneous mixture of polyolefin solids and organic peroxide without melting the polyolefin solids during manufacture, wherein the method comprises applying acoustic energy at a frequency of 20 to 100 hertz (Hz) to a heterogeneous mixture comprising polyolefin solids (A) and organic peroxide (B) for a period of time sufficient to substantially intermix (totally or completely homogenize) the polyolefin solids (A) and the organic peroxide (B) while maintaining the temperature of the heterogeneous mixture (and, for that matter, the temperature of the homogeneous mixture made therefrom) below the melting temperature of the polyolefin solids (A), thereby making the mixture homogeneous without melting the polyolefin solids (A); wherein the polyolefin solids (A) are from 95.0 to 99.9 percent by weight (% wt) and the organic peroxide (B) is from 0.1 to 5.0% by weight, respectively, of the combined weights of constituents (A) and (B). The heterogeneous mixture and the homogeneous mixture made from it by the acoustic energy application step may comprise 0, 1, 2, or more optional additives. The total weight of all constituents of the heterogeneous mixture, including the optional additives, is 100.0% by weight, and the total weight of all constituents of the homogeneous mixture, including the optional additives, is 100.0% by weight. The method may further comprise the limitation that the heterogeneous mixture is not mechanically agitated (not mixed by mechanical means) during the acoustic energy application step. The method may further comprise the limitation that the organic peroxide does not decompose or degrade during the acoustic mixing step (as indicated by curing and / or mechanical properties). Aspect 2. The method of aspect 1 wherein the acoustic energy application step is characterized by any one of the limitations (i) to (v): (i) the frequency is from 50 to 70 Hz, alternatively from 55 to 65 Hz, alternatively from 58 to 62 Hz, alternatively from 59 to Hz; (ii) the time period is from 0.5 minutes to 4 hours, alternatively from 0.5 minutes to 2 hours, alternatively from 1 minute to 60 minutes, alternatively from 1 minute to 10 minutes; (iii) both (i) and (ii); (iv) maintaining the temperature of the heterogeneous mixture below the melting temperature of the polyolefin solids (A) comprises maintaining the temperature of the heterogeneous mixture (and, in fact, the temperature of the homogeneous mixture prepared from it) between -20° and 109°C, alternatively from 10° to 109°C, alternatively from 15° to 99°C, alternatively from -20° to 50.0°C, alternatively from 20.0° to 39.9°C, alternatively from 20.0° to 29.9°C. (for example, 25°C ± 3°C); and (v) both (iv) and any one of (i) to (iii). The temperature may be the outside ambient temperature. The intensity is sufficient to move materials with sufficient amplitude to be effective for mixing without mechanical agitation.An acoustic mixer device can be used to perform the acoustic energy application step, where the operator of the acoustic mixer device sets the frequency. Aspect 3. The method of aspect 1 or 2 wherein the polyolefin solids (A) are characterized by a physical form (i.e., a solid particle form) that is a powder, pellets, granules, or a mixture of any two or more of these, and by a melting temperature that is 61° at cq Lznn / zznz / E / YiAi 180 °C, alternatively from 90 °C to 180 °C, alternatively from 110 °C to 174 °C, alternatively from 120 °C to 180 °C; and the organic peroxide (B) is a liquid organic peroxide or a solid organic peroxide. The solid organic peroxide may be in the form of a powder or pellets and may have a melting point of 24 to 120 °C; alternatively from 35 °C to 120 °C. Aspect 4. The method of any one of aspects 1 to 3, wherein the polyolefin of the polyolefin solids (A) consists essentially of one or more ethylene-based polymers; wherein each ethylene-based polymer is a low-density polyethylene (LDPE) polymer or a combination of the LDPE polymer and a polyolefin selected from the group consisting of: a second LDPE polymer; a linear low-density polyethylene (LLDPE) polymer; and a high-density polyethylene (HDPE) polymer. In other embodiments, the polyolefin of the polyolefin solids (A) consists essentially of an LDPE and a polypropylene (PP) polymer. Aspect 5. The method of any one of aspects 1 to 4 wherein the organic peroxide is a solid organic peroxide. In some embodiments, the solid organic peroxide is selected from: dicumyl peroxide, dilauryl peroxide, dibenzoyl peroxide, and isopropylbenzene of di-2-tert-butylperoxy and alpha,alpha-bis(tert-butylperoxy)diisopropylbenzene. In some embodiments, organic peroxide (B) is a solid organic peroxide that has a melting point Ts, where Ts is above 35 °C, and the temperature of the heterogeneous mixture and the homogeneous mixture independently is from -20 °C to <Ts, alternativamente de 10 °C a <Ts, alternativamente de 15 °C a <Ts, alternativamente de 20.0 °C a <Ts. En algunas modalidades, el peróxido orgánico (B) es un peróxido orgánico sólido que tiene un punto de fusión Ts, en donde el Ts es inferior a 109 °C, y la temperatura de la mezcla heterogénea y la mezcla homogénea, independientemente, es de > Ts at 109 °C, alternatively > Ts at 99 °C, alternatively > Ts at 79 °C, alternatively > Ts at 50 °C, alternatively > Ts at 38 °C. Aspect 6. The method of any one of aspects 1 to 5 wherein the heterogeneous mixture further comprises one or more additives other than the polyolefin solids (A) or the organic peroxide (B), and the acoustic energy application step comprises applying acoustic energy at a frequency of 20 to 100 hertz (Hz) to the heterogeneous mixture comprising the polyolefin solids (A), the organic peroxide (B), and the one or more additives other than a peroxide for a period of time sufficient to substantially intermix (wholly or completely homogenize) the polyolefin solids (A), the organic peroxide (B), and the one or more additives together while maintaining the temperature of the heterogeneous mixture (and, for that matter, the temperature of the homogeneous mixture made therefrom) below the melting temperature of the polyolefin solids (A), thereby making the homogeneous mixture further comprising the one or more additives,without melting the polyolefin solids (A). In some embodiments, one or more additives are separate ingredients in the heterogeneous mixture and are not contained in the polyolefin solids (A). In other embodiments, at least one of the one or more additives is premixed into the polyolefin solids (A) by melt mixing and granulation, such that the heterogeneous mixture comprises the organic peroxide (B) and the composite solids (e.g., granules) comprising the polyolefin (A) mixed with the one or more additives. Aspect 7. The method of aspect 6 wherein at least one, alternatively all but one, or alternatively each or more additives other than constituents (A) or (B) are independently a liquid additive or a particulate solid additive selected independently of additives (C) to (D): a liquid or particulate solid antioxidant (C); and a liquid or particulate solid stabilizer (D) for stabilizing the homogeneous mixture against the effects of ultraviolet light and / or heat. In some embodiments, the one or more additives may further comprise at least one of a colorant, a crosslinking co-agent for increasing the crosslinking density in a crosslinked homogeneous mixture made by heating the homogeneous mixture, a processing aid, a flame retardant, and a solid filler. Aspect 8. The method of aspect 7 wherein the one or more additives include one or more of the solid antioxidant (C)-1: tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5triazine-2,4,6-trione (TMTT); solid antioxidant (C)-2: distearyl thiodipropionate (DSTDP); and solid stabilizer (D)-1: N,N'-bisformyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-hexamethylenediamine (BBHMDA). Aspect 9. The method of any one of aspects 1 to 8 further comprising, prior to the acoustic energy application step, a step of melting the polyolefin solids (A) to make a melt thereof, and mechanically mixing the melt of (A) with one or more additives other than organic peroxide (B) to give an organic peroxide-free melt (B); shaping the melt to give a shaped melt; and cooling the shaped melt to give polyolefin solids (A) containing one or more additives; and combining the polyolefin solids (A) containing one or more additives with the organic peroxide (B) to give the heterogeneous mixture. The shaping step may comprise extruding the melt as a coating (e.g., a coating composition) onto a conductive core (e.g., a cable, optical fiber, or both) and allowing the coating to solidify to form a coated conductor (e.g., a cable, optical fiber, or both).e.g., coated) comprising the conducting core and a solid in the form of a coating that at least partially covers (e.g., encases) the conducting core. Aspect 10. The method of any one of aspects 1 to 9 further comprising curing the homogeneous mixture (for example, by heating it to a temperature of 180° to 220°C) to give a homogeneous crosslinked product. The method comprises a mixing step that essentially consists of the acoustic energy application step. This means that the method achieves complete intermixing of the polyolefin solids and the organic peroxide without mechanically mixing or melting the polyolefin solids, and it does so rapidly relative to soaking, for example, in less than 10 minutes. The embodiments of the method do not soak the polyolefin solids with the organic peroxide because they initiate the acoustic energy application step shortly after bringing the polyolefin solids and the organic peroxide into contact, for example, within 0 to 10 minutes, alternatively from 0.1 to 5 minutes, or alternatively from 0.1 to 1 minute of contact. The method's embodiments may further include, in the heterogeneous mixture and thus in the homogeneous mixture cq Lznn / zznz / E / YiAi made from it by the acoustic energy application step, one, two, or more additives, for example, one or more liquid and / or solid additives such as the liquid or solid particulate antioxidant(s) (C) and / or the liquid or solid particulate stabilizer (D). Such embodiments have the additional benefit of making the homogeneous mixture comprising the polyolefin solids (A), the organic peroxide (B), and the one, two, or more additives without mechanically mixing or melting the polyolefin solids (A).That is, the polyolefin solids (A) of the homogeneous mixture of the invention have improved (reduced) thermal exposure relative to a comparative thermal exposure of the polyolefin solids (A) of a comparative homogeneous mixture prepared by a comparative method comprising melt-mixing the polyolefin solids (A) and one, two, or more additives to give a molten mixture; extruding / granulating the molten mixture to give solid granules comprising a homogeneous mixture of polyolefin solids (A) and the one, two, or more additives; and soaking the organic peroxide (B) into the granules. These inventive embodiments also have the additional benefit of producing the inventive homogeneous mixture much faster than the time required by the comparative method to produce the comparative homogeneous mixture (e.g., in 10 minutes versus several hours, respectively). cq Lznn / zznz / E / YiAi The method solves a problem of mixing polyolefin solids with organic peroxide without melting the polyolefin solids, without soaking the organic peroxide in the polyolefin solids, and optionally, without using mechanical mixing means. The acoustic energy application step can achieve such complete and rapid mixing without melting the polyolefin solids. If desired, the method can be performed without mechanical mixing. The acoustic energy application step enables and effectively intermixes the polyolefin solids (A) and the organic peroxide (B) completely and rapidly without melting the polyolefin solids during intermixing. This combination of advantages—mixing completeness, mixing speed, and minimized thermal exposure—is discussed below. Modalities of the method that omit mechanical mixing advantageously avoid the use of expensive mechanical mixing equipment and simplify manufacturing operations. The mixing step involving the application of acoustic energy is meticulous because a homogeneous mixture is achieved. In practical terms, the attainment of homogeneity can be recognized by visual inspection or by taking samples of the mixture as it transitions from a heterogeneous to a homogeneous state and measuring a property of the sample. For example, homogeneity is achieved when the sampling error of the measurement is negligible or identical to the total measurement error. All other things being equal, (i) the higher the acoustic energy, the shorter the time required to achieve homogeneity, and vice versa; and (ii) the closer the frequency is to a resonance with the polymeric solids, the shorter the time required to achieve homogeneity, and vice versa. The intermixing of the acoustic energy application step is fast because the complete intermixing can be achieved in a matter of seconds or minutes, for example, from 0.5 minutes to 10 minutes, alternatively from 1.0 to 5.0 minutes, alternatively from 2 to 4 minutes. The acoustic energy application step minimizes the thermal exposure of the homogeneous mixture because it converts the heterogeneous mixture into a homogeneous mixture without melting the polyolefin solids (A). In fact, if desired, it can be advantageously performed at a temperature well below the melting point of the polyolefin solids (A). For example, the acoustic energy application step can be performed at a temperature of 0° to 39°C, alternatively from 10° to 34°C, or alternatively from 20° to 30°C. Because the acoustic energy application step can be performed at a temperature well below the melting temperature of the polyolefin solids (A), the modifications to this step can be advantageously carried out in an oxygen-containing atmosphere, such as air. Oxygen-containing atmospheres can be detrimental to conventional melt blending or melt compounding operations where exposure of a molten mass of polyolefin solids (A) containing the organic peroxide (B) and optionally additives to air at high temperatures, such as 140° to 200°C, could undesirably cause scaling (premature curing) or oxidative and / or thermal decomposition of the polyolefin solids (A) and / or additives.Thus, the acoustic energy application step advantageously keeps the temperature of the polyolefin solids (A) and the other constituents of the heterogeneous mixture containing them and the homogeneous mixture made from these, below the melting temperature of the polyolefin solids (A). Even in variations of the method that also include the step of melting and extruding the homogeneous mixture to produce a shaped article, the homogeneous mixture has had less thermal exposure than a comparable homogeneous mixture made by melt blending or melt compounding the heterogeneous mixture. This is because it has avoided the melt blending / compounding exposure time, which would otherwise have added 10 or more minutes of exposure at temperatures of 140°C or higher. Therefore, without being tied to the theory, it is believed that in relation to the comparative homogeneous mixture, the inventive homogeneous mixture may have improved curing properties (e.g., lower ML, higher MH and / or higher MH - ML as measured by the Curing Properties Test Method described below), improved mechanical properties (e.g., higher tensile strength, lower elongation at break) as measured by the Mechanical Properties Test Method described below, and / or improved heat aging performance. These characterizations of mechanical and curing properties show that the homogeneous mixture of the invention can be prepared rapidly (in less than 10 minutes, e.g., 3 minutes) at moderate temperatures (e.g., < 30 °C, e.g., 23 °C to 26 °C) and achieve the organic peroxide (B) loading levels typically used for curing polyolefins. Furthermore, the homogeneous mixture of the invention can be cured to provide curing and mechanical properties that are improved compared to those obtained from a comparative example made by a conventional two-step process comprising melt-mixing the polyolefin solids with all additives (except the organic peroxide) at 120 °C to give an intermediate mixture, then extruding strands of this mixture at a temperature of 10 °C. 150°C / 170°C / 190°C / 195°C, granulating and soaking organic peroxide in the granules at an elevated temperature (70°C) for an extended period (typically 8 to 10 hours). In fact, as indicated by a lower initial ML value and a higher final MH value, obtained by curing the homogeneous mixture of the invention using a moving die rheometer, it can be concluded that the acoustic mixing method of the invention reduces the decomposition of organic peroxide during the preparation of the homogeneous mixture of the invention compared to the preparation of the mixture mixed by comparative melt / soaking. As a result, it can also be seen that a higher degree of crosslinking is achieved in the homogeneous mixture of the invention compared to the mixture mixed by comparative melt / soaking.This inventive advantage is also reflected in the inventive cured product having a lower elongation at break value (i.e., greater crosslinking) than the comparative cured product. No technical explanation is required of how the acoustic energy application step creates a homogeneous mixture from a heterogeneous mixture without mechanical mixing. However, while not explicitly linked to the theory, it is believed that applying acoustic energy at a frequency of 20 to 100 Hz generates sound waves that cause the polyolefin solids (A) and the organic peroxide (B) to oscillate rapidly. They undergo a relatively large physical displacement, the magnitude and speed of which are thought to be a function of the acoustic frequency and intensity. This oscillation of the polyolefin solids (A) and the organic peroxide (B) results in their rapid intermixing to form the homogeneous mixture. The homogeneous mixture is thus prepared without melting the polyolefin solids (A) and, optionally, without mechanically mixing the polyolefin solids (A) and the organic peroxide (B).Therefore, the present method is different from previous mixing methods, which are based on the mechanical mixing of solids (e.g., in a stirred tank device) or melts (e.g., in a twin-screw extruder device) of polyolefins with organic peroxide (B). Sound with a frequency below 20 Hertz (Hz) is called infrasound; from 20 Hz to 20 kilohertz (kHz), acoustic; and above 20 kHz (up to 200 megahertz (MHz) or more), ultrasound. While not theoretically binding, it is believed that infrasound, ultrasound, and acoustic sound above 100 Hz cannot, on their own, rapidly oscillate the polyolefin solids (A) or organic peroxide (B) in the heterogeneous mixture in a way that creates a relatively large physical displacement of these solids and thus produces a homogeneous mixture. The application of acoustic energy at a frequency of 20 to 100 Hz is referred to herein as acoustic mixing. To apply effective acoustic energy by practical means, the method can homogenize the mixture in an acoustic mixing device. Such a device can be free of components that might interfere with or dampen the acoustic energy during the acoustic energy application step. Acoustic mixing devices for various scales, from the laboratory bench to commercial manufacturing, are commercially available, including the resonant acoustic mixers from Resodyn Acoustic Mixers, Butte, Montana, USA. The method may further include a limitation without mechanically agitating (moving by mechanical means) the heterogeneous mixture during the acoustic energy application step. Mechanical movement means movement set in motion manually or by a machine, through a direct contact force where a physical object (e.g., a stirring paddle, screw, plunger, or filler) touches and thus moves a material. Examples of mechanical movement include stirring, screw mixing, plunger mixing, blender mixing, and other direct physical contacts. Contact force does not include electromagnetic force, gravity, acoustic force, or convective force. In addition to the acoustic energy application step, some variations of the method may also include one or more optional steps. Typically, the optional step does not occur simultaneously with the acoustic energy application step. An optional step may occur before or after the acoustic energy application step, as described herein. The method may further comprise, after the acoustic energy application step, a subsequent step of melting and shaping the homogeneous mixture made by the acoustic energy application step, and cooling the shaped homogeneous mixture to make a manufactured article comprising the shaped homogeneous mixture. The method may further comprise, after the acoustic energy application step, the step of melting the polyolefin solids (A) of the homogeneous mixture to make a homogeneous melt comprising the organic peroxide (B), one or more additives, if present, and a molten mass of polyolefin solids (A); shaping the homogeneous melt to give a shaped melt; and cooling the shaped melt to give a shaped solid. The melting and shaping may be performed without mechanical agitation; alternatively, mechanical agitation may be employed. The shaping may comprise coating, extrusion, molding, granulation, or extrusion and granulation. In some embodiments, the shaping comprises extruding the homogeneous melt and granulating the extrudate to make granules of the homogeneous mixture. The shaped solid may be useful as a manufactured article.The manufactured article may be a coating layer of a coated conductor such as a telecommunications or power cable. The method may further comprise the optional step of curing (crosslinking) the solid coating to yield a coated conductor comprising the conductive core and a cured coating that at least partially covers the conductive core. This aspect can be used to manufacture a fabricated article comprising a power cable, such as a low-voltage power cable. The method may further comprise, prior to the acoustic energy application step, an optional step for preparing the heterogeneous mixture. The heterogeneous mixture may be made by contacting the polyolefin solids (A) with the organic peroxide (B) and, optionally, one or more additives, to create the heterogeneous mixture comprising constituents (A) and (B) and, if present, the one or more additives. The contact step is performed in the absence of acoustic energy and, ideally, without melting the polyolefin solids (A). The contact constituents (A) and (B), and optionally one or more additives to make the heterogeneous mixture, may be made simultaneously (all at once) or sequentially, or a combination of some all at once and the rest sequentially (step by step). Simultaneous contact may comprise combining constituents (A), (B), and any one or more additives together at the same time in a container to make the heterogeneous mixture. Stepwise contact can comprise different modalities. In some modalities, sequential contact can comprise contacting the organic peroxide (B) with at least one of the one or more additives to give a first precontacted batch that is free of (A), and then contacting the polyolefin solids (A) with the first precontacted batch to carry out the heterogeneous mixture modality comprising (A), (B) and the one or more additives. Alternatively, the sequential contact may comprise contacting the polyolefin solids (A) with at least one of the one or more additives to give a second precontacted batch that is free of (B), and then contacting the organic peroxide (B) with the second precontacted batch to perform the heterogeneous mixing modality of (A), (B) and the one or more additives. Alternatively, a combination of the two above sequential modes can be performed using a first additive to make the first pre-contacted batch and a second additive to make the second pre-contacted batch, wherein the first and second additives are the same or different, and then contacting the first and second pre-contacted batches together to perform the heterogeneous mixture mode comprising (A), (B) and the one or more additives. Prior to the contact step, the polyolefin solids (A) used to make the heterogeneous mixture may be free of the organic peroxide (B), and conversely, the organic peroxide (B) used may be free of the polyolefin solids (A). Alternatively, in some embodiments, a stock mixture comprising a larger charge than the final charge of organic peroxide (B) dispersed in a portion of the polyolefin solids (A) may be prefabricated, and the stock mixture may then be contacted with the remaining portion of the polyolefin solids (A) to make the heterogeneous mixture. The same or a different stock mixture may comprise one or more additives, which may be contacted with a remaining portion of the polyolefin solids (A) and the organic peroxide (B) to make that embodiment of the heterogeneous mixture. The stock mixture may be prepared by acoustic mixing or conventional melt mixing. The polyolefin (A) solids used in the contact step to make the heterogeneous mixture may be free of one or more additives (e.g., the polyolefin (A) solids may consist of pellets or granules of virgin polyolefin resin). Alternatively, the polyolefin (A) solids used in the contact step to make the heterogeneous mixture may contain some or all of one or more additives, such as one or more antioxidants and heat stabilizers. These additives may have been premixed into pellets or granules of virgin polyolefin resin by melt blending or melt composition of the virgin resin to make the polyolefin (A) solids containing one or more antioxidants and heat stabilizers. The heterogeneous mixture used in the acoustic energy application step can be freshly prepared by the contact step. Freshly prepared means that the time between the contact step and the start of the acoustic energy application step can be less than 30 minutes, alternatively less than 15 minutes, alternatively less than 10 minutes, or alternatively less than 5 minutes. Alternatively, the heterogeneous mixture used in the acoustic energy application step can be pre-aged. Pre-aged means that the time between the contact step and the start of the acoustic energy application step can be at least 30 minutes, alternatively more than 60 minutes, or alternatively more than 120 minutes. Homogeneous mixing is achieved through the acoustic energy application step of the method. The homogeneous mixture can be characterized as described above. While not strictly bound by theory, the product of this step can be characterized as homogeneous because the organic peroxide (B) is adsorbed substantially uniformly onto the outer surfaces and any accessible inner surfaces of the polyolefin solids (A). Substantially uniform adsorption means that virtually all accessible surfaces of the polyolefin solids (A) have at least some adsorbed organic peroxide (B), although the amounts of adsorbed organic peroxide (B) may vary across surfaces. Once adsorbed onto the surfaces of the polyolefin solids (A), the organic peroxide (B) can remain there until, in an optional subsequent step, the polyolefin solids (A) are melted. When the heterogeneous mixture and the homogeneous mixture made from it include one or more additives, the polyolefin solids (A) may be from 50 to 99.8 percent by weight, the organic peroxide (B) may be from 0.1 to 5.0 percent by weight, and the total weight of one or more additives may be from 0.1 to 45 percent by weight, all based on the weight of the heterogeneous mixture and the homogeneous mixture, respectively; and wherein the total weight of all constituents of the heterogeneous mixture is 100.0 percent by weight and the total weight of all constituents of the homogeneous mixture is 100.0 percent by weight. Without intending to impose any theory, it is believed that the total weight of the homogeneous mixture is equal to the total weight of the heterogeneous mixture from which it is made. That is, it is believed that the application of acoustic energy does not result in any significant weight loss or gain when transitioning from the heterogeneous to the homogeneous mixture. Polyolefin solids (A). A finely divided, solid material composed of polyolefin macromolecules independently comprising at least 5, alternatively from 10 to 200,000 constituent units derived from the polymerization of one or more monomers with olefin functionality. Polyolefin can be a homopolymer or a copolymer. A homopolymer is made by polymerizing only one olefin monomer. A copolymer is made by polymerizing at least two different olefin monomers. A copolymer can be a bipolymer made by polymerizing two different olefin monomers, a terpolymer made by polymerizing three different olefin monomers, or a tetrapolymer made by polymerizing four different olefin monomers. A polyolefin that is a copolymer can be a block copolymer or a random copolymer. Examples of monomers with definite functionality used to manufacture polyolefin(s) from polyolefin solids (A) are ethylene, propene, alpha-olefins (C4-C20), cyclic alkenes (e.g., norbornene), dienes (e.g., 1,3-butadiene), unsaturated carboxylic esters, and hydrolyzable silanes with definite functionality. Examples of alpha-olefins (C4-C20) are an alpha-olefin (C4-C8) such as 1-butene, 1-hexene, or 1-octene; and an alpha-olefin (C10-C20). An example of a diene is 1,3-butadiene. Examples of unsaturated carboxylic esters are alkyl acrylates, alkyl methacrylates, and vinyl carboxylates (e.g., vinyl acetate). Examples of hydrolyzable silanes with olefin functionality are vinyltrialkoxysilanes, vinyltris(dialkylamino)silanes, and vinyl(trioximo)silanes. Examples of such polyolefins are a polyethylene homopolymer; an ethylene / alpha-olefin copolymer; a functional polyethylene copolymer (hydrolyzable silyl group) (HSG-FP copolymer); an ethylene / unsaturated carboxylic ester copolymer (e.g., ethylene / vinyl acetate (EVA) copolymer or ethylene / alkyl (meth)acrylate (EAA or EAM) copolymer); a halogenated polyolefin (e.g., a chlorinated polyolefin such as a poly(vinyl chloride) polymer); and a combination of any two or more of these. cq Lznn / zznz / E / YiAi In some embodiments, the polyolefin of the polyolefin solids (A) is an ethylene-based polymer. An ethylene-based polymer comprises 51 to 100 wt% of ethylene units derived from the polymerization of ethylene and 49 to 0 wt% of comonomeric units derived from the polymerization of one, or alternatively two, functional olefinic monomers (comonomer). The comonomer may be selected from propylene, an alpha-olefin (C4-C20), and 1,3-butadiene. The alpha-olefin (C4-C20) may be an alpha-olefin (C4-C8) such as 1-butene, 1-hexene, or 1-octene. Examples of suitable ethylene-based polymers include polyethylene homopolymers, ethylene / alphaolefin (C4-C20) copolymers, ethylene / propylene copolymers, ethylene / propylene / diene monomer (EPDM) copolymers such as ethylene / propylene / 1,3-butadiene terpolymers, and ethylene / 1-butene / styrene copolymers. Examples of suitable ethylene / alphaolefin (C4-C20) copolymers include ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, and ethylene / 1-octene copolymers. Ethylene-based polymers can be ultra-low-density polyethylene (ULDPE), very-low-density polyethylene (VLDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), or ultra-high-density polyethylene (UHDPE). The Dow cq Lznn / zznz / E / YiAi Chemical Company sells many ethylene-based polymers under trade names such as AFFINITY, ALTANE, DOWLEX, ENGAGE, FLEXOMER, and INFUSE. Other suppliers sell other ethylene-based polymers under trade names such as TAFMER, EXCEED, and EXACT. In some embodiments, polyolefin solids (A) consist of solids of only one ethylene-based polymer (e.g., only LLDPE, or only LDPE, or only MDPE, or only HDPE). In other embodiments, the polyolefin solids (A) comprise two or more different ethylene-based polymers. In some such embodiments, the polyolefin solids (A) comprise a mixture of particles of first solids of a first linear low-density polyethylene (first LLDPE) and at least one of the second solids of a medium-density polyethylene (MDPE) and third solids of a second LLDPE that is different from the first LLDPE. In some embodiments, the particle combination comprises the first LLDPE and the MDPE; alternatively, the first LLDPE and the second LLDPE; or alternatively, each of the first LLDPE, the MDPE, and the second LLDPE. In some embodiments, the ethylene-based polymer that is free of halogens and silicon atoms is a polyethylene homopolymer, a poly(ethylene-co-l-butene) copolymer, a poly(ethylene-co-l-hexene) copolymer, a poly(ethylene-co-l-octene) copolymer, or a combination of two or more of these. In some such embodiments, the polyolefin is a low-density polyethylene (LDPE), a linear low-density polyethylene (LLDPE), a medium-density polyethylene (MDPE), a high-density polyethylene (HDPE), or a combination of any two or more of these (for example, a combination of an LLDPE and an MDPE or a combination of two LLDPEs and an MDPE). In some forms, the ethylene-based polymer is a low-density polyethylene (LDPE) that has a density of 0.915 to 0.924 g / cc and a melt index (12, 190 °C, 2.16 kg) of 1.5 to 2.4 g / 10 min. Polyolefin solids (A) may consist essentially of a single polyolefin.In some embodiments, the polyolefin solids (A) consist essentially of two or three different polyolefins. Such embodiments of polyolefin solids (A) may consist essentially of solids in which each particle of the solids comprises a polymer mixture of the two or more different polyolefins. Other embodiments of this type may comprise a mixture of particles of first solids consisting essentially of a first polyolefin only, second solids consisting essentially of a second polyolefin only, and optionally, third solids consisting essentially of a third polyolefin only; wherein the first and second polyolefins and, if present, the third polyolefin, are different from each other.Other embodiments may still comprise a mixture of first solid particles consisting essentially of a first polyolefin only and second solid particles consisting essentially of a mixture of polymers of a second polyolefin and a third polyolefin; wherein the first and second polyolefins are different from each other and the first and third polyolefins are the same or different. In some embodiments, the polyolefin of the polyolefin solids (A) is free of halogen and / or silicon atoms. In some embodiments, the polyolefin is also free of oxygen and / or nitrogen atoms. In some embodiments, the ethylene-based polymer is free of halogen and / or silicon atoms. In some embodiments, the ethylene-based polymer is also free of oxygen and / or nitrogen atoms. In other embodiments, the ethylene-based polymer is free of halogen and / or silicon atoms and free of oxygen and nitrogen atoms derived from a monomer of definition containing oxygen and / or nitrogen, but contains crosslinks containing oxygen and / or nitrogen atoms derived from crosslinking co-agents containing oxygen and / or nitrogen (e.g., trialyl isocyanurate or 2,4,6-tris(diallylamino)-1,3,532 triazine). In some embodiments, the polyolefin of the polyolefin solids (A) is a propylene-based polymer comprising 51 to 100 wt% of propylene units derived from the polymerization of propylene and 49 to 0 wt% of comonomeric units derived from the polymerization of one or alternatively two monomers with olefin functionality (comonomer) selected from ethylene; an alpha-olefin (C4-Ca) such as 1-butene, 1-hexene or 1-octene. Polyolefin (A) solids can be porous or non-porous. Polyolefin (A) solids can comprise a powder, pellets, or granules. Polyolefin solids (A) may have a melting point at which melting begins or starts that is 60 °C or higher, alternatively higher than 100 °C, or alternatively higher than 110 °C. Polyolefin solids (A) may have a melting point at which melting ends or is completed of at most 220 °C, alternatively at most 180 °C, or alternatively at most 150 °C. The polyolefin solids (A) of the heterogeneous mixture can be characterized by an average particle size of 10 to 500 particles per gram (ppg), alternatively 11 to 80 ppg, alternatively 20 to 40 ppg, measured by counting. cq Lznn / zznz / E / YiAi Organic peroxide (B). A molecule containing carbon atoms, hydrogen atoms, and two or more oxygen atoms, and having at least one -O-O- group, provided that when there is more than one -O-O- group, each -O-O- group is indirectly bonded to another -O-O- group through one or more carbon atoms; or a group of such molecules. Organic peroxide (B) can be used to cure the homogeneous mixture of the invention by heating the homogeneous mixture to a temperature equal to or higher than the decomposition temperature of organic peroxide (B). The organic peroxide (B) can be a monoperoxide of formula R°-0-0-R°, where each R° is independently an alkyl (C1-C20) group or an aryl (C6-C20) group. Each alkyl (C1-C20) group is either unsubstituted or substituted with one or two aryl (C6-C12) groups. Each aryl (C6-C20) group is either unsubstituted or substituted with one to four alkyl (C1-C10) groups. Alternatively, (B) can be a diperoxide of formula R°-0-0-R-0-0-R°, wherein R is a divalent hydrocarbon group such as an alkylene (C2-C10), cycloalkylene (C3C10), or phenylene, and each R° is as defined above.Organic peroxide (D) can be bis(1,1-dimethylethyl) peroxide; bis(1,1-dimethylpropyl) peroxide; 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexane; 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexyne; 4,4-bis(l,l-dimethylethylperoxy)valeric acid; butyl ester; l,l-bis(l,l-dimethylethylperoxy)-3,3,5-trimethylcyclohexane; benzoyl peroxide; tere-butyl peroxybenzoate; di-tert-camyl peroxide (DTAP); bis(alpha-t-butylperoxyisopropyl)benzene (BIPB); isopropylcumyl t-butyl peroxide; t-butylcumyl peroxide; di-t-butyl peroxide; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexyne-3,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; isopropylcumyl cumylperoxide; butyl 4,4-di(tert-butylperoxy) valerate; or di(isopropylcumyl peroxide); or dicumyl peroxide. The organic peroxide (B) may be dicumyl peroxide. In some respects, only a mixture of two or more organic peroxides (B) is used, for example, a 20:80 (w / w) mixture of tert-butyl cumyl peroxide and bis(tert-butyl peroxy isopropyl)benzene (for example, LUPEROX D446B, which is commercially available through Arkema). In some respects, at least one, alternatively, each organic peroxide (B) contains a -O-O- group. Organic peroxide (B) can be at least one liquid organic peroxide (e.g., tere-butyl peroxyacetate). Alternatively, organic peroxide (B) can be at least one solid organic peroxide (e.g., dicumyl peroxide). Alternatively, organic peroxide (B) can be a combination of two liquid organic peroxides, two solid organic peroxides, or one liquid organic peroxide and one solid organic peroxide. The term liquid organic peroxide (B) means any of the organic peroxides of formula R°-OO-R° or formula R°-OOROO-R° that has an amorphous state of matter at room temperature (e.g., 23 °C) that is intermediate between a compound and a solid and that has a stable volume but not a definite shape. In some embodiments, the liquid organic peroxide is tert-butyl peroxyacetate. The embodiment of solid organic peroxide (B) means any of the organic peroxides of formula R°-OO-R° or formula RC-OOROO-R° that has a stable volume and definite shape at room temperature (e.g., 23 °C). It may be amorphous, crystalline, or semicrystalline. In some embodiments, the solid organic peroxide is selected from: dicumyl peroxide, dilauryl peroxide, dibenzoyl peroxide, and isopropylbenzene, di-2-tert-butylperoxy, and α,α-bis(β-butylperoxy)diisopropylbenzene. Organic peroxide (B) can be from 0.05 to 3.0% by weight, alternatively from 0.1 to 3% by weight, alternatively from 0.5 to 2.5% by weight of the heterogeneous mixture and the homogeneous mixture prepared from it. One or more optional additives. A substance other than polyolefin solids (A) or organic peroxide cq Lznn / zznz / E / YiAi (B) is added to the heterogeneous mixture to improve one or more properties of the homogeneous mixture made from it. Not being bound by theory, it is believed that the acoustic energy application step of the method does not decompose any additive, so if the heterogeneous mixture contains an additive, that additive will also be contained in the homogeneous mixture made from that heterogeneous mixture. In some embodiments, the heterogeneous mixture and the homogeneous mixture made from it are free of additives. In other embodiments, the heterogeneous mixture and the homogeneous mixture prepared from it contain one or more additives. The homogeneous mixture may further comprise one or more additional additives that are not present in the heterogeneous mixture from which it was made, but which are added to the homogeneous mixture after the acoustic energy application step. The method of adding the additional additives may comprise melting the polyolefin solids (A) as in a melt-blend or melt-composition operation. Alternatively, the method of adding the additional additives may comprise a non-melting operation such as passively soaking or embedding the additional additives in the homogeneous mixture at a temperature of 20° to 90°C (e.g., 50° to 80°C). Liquid additives and particulate solid additives having a melting point below 90°C are suitable for such soaking or immersion methods. In some embodiments, the heterogeneous mixture and the homogeneous mixture made from it contain one or more additives, alternatively two or more additives, alternatively three or more additives, alternatively four or more additives, or alternatively five or more additives. In some embodiments, the heterogeneous mixture and the homogeneous mixture made from These contain a total of 10 or fewer additives, alternatively a total of 9 or fewer additives, alternatively a total of 8 or fewer additives, alternatively a total of 7 or fewer additives, alternatively a total of 6 or fewer additives. In some embodiments, at least one, alternatively all but one, or alternatively each of the one or more additives other than constituents (A) or (B) is independently a liquid or particulate solid additive selected from a liquid or particulate solid antioxidant (C) and a liquid or particulate solid stabilizer (D) to stabilize the homogeneous mixture against the effects of ultraviolet light and / or heat. In some embodiments, the one or more additives may comprise a colorant (e.g., carbon black or TiO2), a crosslinking co-agent (e.g., trialyl isocyanurate (TAIC)); a processing aid (e.g., a fluoropolymer or polydimethylsiloxane); a flame retardant (an alumina), and / or a filler (e.g., fumed silica). Each additive independently may be a liquid additive or a particulate solid additive.In some embodiments, the heterogeneous mixture and the homogeneous mixture from which it was prepared contain at least one solid particulate additive, alternatively at least one liquid additive, or alternatively at least one solid particulate additive and at least one liquid additive. Each solid particulate additive may independently have a melting point lower than, equal to, or higher than the melting temperature of the polyolefin solids (A). The optional liquid or particulate solid additive antioxidant (C): an organic molecule that inhibits oxidation, or a group of such molecules. The antioxidant (C) has a different composition from the stabilizer (D), meaning that when the heterogeneous or homogeneous mixture contains both (C) and (D), the compound used as (C) is different from that used as (D). The antioxidant (C) functions to provide antioxidant properties to the heterogeneous or homogeneous mixture and / or a cured polymer product made by curing the homogeneous mixture. Examples of suitable (C) are bis(4-(1-methyl-1-phenylethyl)phenyl)amine (e.g., NAUGARD 445); 2,2'-methylene-(4-methyl-6-1-butylphenol) (e.g., VANOX MBPC); 2,2'-thiobis(2-t-butyl-5-methylphenol (CAS No. 90-66-4; 4,4'-thiobis(2-t-butyl-5-methylphenol) (also known as 4,4'-thiobis(6-tert-butyl-cresol) , No.of CAS 96-69-5, known in the market as LOWINOX TBM-6); 2,2'-thiobis(6-t-butyl-4-methylphenol (CAS No. 90-66-4, marketed as LOWINOX TBP-6); tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazin-2,4,6-trione (e.g., CYANOX 1790); pentaerythritol tetrakis(3-(3,5bis(1,1-dimethylethyl)-4-hydroxyphenyl)propionate (e.g., IRGANOX 1010, CAS No. 6683-19-8); 2,2'-thiodietandiyl ester of 3,5-bis(1,1-dimethylethyl)4-hydroxybenzenepropanoic acid (e.g., IRGANOX 1035, no. of CAS 41484-35-9); distearyl thiodipropionate (DSTDP); dilauryl thiodipropionate (eg, IRGANOX PS 800); Stearyl 3(3,5-di-t-butyl-4-hydroxyphenyl)propionate (e.g., IRGANOX 1076); 2,4-bis(dodecylthiomethyl)-6-methylphenol (IRGANOX 1726); 4,6-bis(octylthiomethyl)-o-cresol (e.g.,. IRGANOX 1520); and 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide (IRGANOX 1024). (C) may be 4,4'-thiobis(2-tert-butyl-5-methylphenol) (also known as 4,4'-thiobis(6-tert-butyl-m-cresol)); 2,2'-thiobis(6-tert-butyl-4-methylphenol); tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazin-2,4,6-trione; distearyl thiodipropionate; or dilauryl thiodipropionate; or a combination of any two or more of these. The combination may be tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazin-2,4,6-trione and distearyl thiodipropionate. The heterogeneous and / or homogeneous mixture may be free of (C). When present, (C) The antioxidant can be from 0.01 to 1.5% by weight, alternatively from 0.1 to 1.0% by weight of the total weight of the heterogeneous and / or homogeneous mixture. Optional liquid or particulate solid additive (D): a stabilizer to stabilize the heterogeneous and / or homogeneous mixture against ultraviolet light (UV stabilizer). The stabilizer (D) differs in composition from the antioxidant (C), meaning that when the mixture contains both (C) and (D), the compound used as (C) is different from the one used as (D). Examples include a hindered amine light stabilizer (HALS), a benzophenone, or a benzotriazole. The UV stabilizer (D) may be a molecule containing a basic nitrogen atom bonded to at least one spherically hindered organogroup, acting as an inhibitor of degradation or decomposition, or a group of molecules. The HALS is a compound with a spherically hindered amino functional group that inhibits oxidative degradation and may also increase the shelf life of the homogeneous mixture containing the organic peroxide (B).Examples of suitable (D) are butanedioic acid dimethyl ester, polymer with 4-hydroxy. 2,2,6,6-tetramethyl-l-piperidinethanol (CAS No. 65447-770, trade name LOWILITE 62); and N,N'-bisformyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine (CAS No. 124172-53-8, trade name Uvinul 4050 H). The heterogeneous and / or homogeneous mixture may be free of (D). When present, the UV stabilizer (D) may be 0.001 to 1.5 wt., alternatively 0.002 to 1.0 wt., or alternatively 0.05 to 0.1 wt. of the heterogeneous and / or homogeneous mixture. The manufactured article. The article manufactured from the homogeneous mixture may comprise a shaped form thereof. Some examples are a coating on a substrate, a tape, a film, a laminate layer, a foam, and a pipe. The coated conductor. The manufactured article may be the coated conductor, comprising a conductive core and a polymer layer that at least partially surrounds the conductive core, comprising at least a portion of the polymer layer comprising the homogeneous mixture, or a cured polymer product resulting from the curing thereof. The entire polymer layer, or only a portion thereof, may comprise the cured polymer product. The conducting core can be linear in shape (e.g., like a wire) with a length and proximal and distal ends separated from each other by the length of the linear shape; and the polymer layer can surround the conducting core except for the proximal and distal ends. The coated conductor may further comprise one or more additional polymer layers, which may or may not independently comprise the cured polymer product; and / or an outer protective layer (e.g., a metal sheath or jacket). The coated conductor may comprise one or two insulating layers, at least one of which comprises the cured polymer product; alternatively or additionally, one or two semiconducting layers, at least one of which comprises the cured polymer product containing carbon black; alternatively or additionally, an outer protective layer comprising the cured polymer product. High-density polyethylene or HDPE. A polyethylene homopolymer or poly(ethylene-co-l-alkene) copolymer having a density of 0.940 to 0.980 g / cm3, measured according to ASTM D792-13; wherein the 1-alkene comonomer is a 1-alkene (C4-C20) such as a 1-alkene (C4-C8) such as 1-butene, 1-hexene, or 1-octene. Low-density polyethylene or LDPE. A poly(ethylene-co-l-alkene) copolymer having a density of 0.871 to less than 0.930 grams per cubic centimeter (g / cm3), as measured according to ASTM D792-13; and having a significantly lower amount of short-chain branching per 1000 carbon atoms (SCB / 1000C) than LLDPE, wherein SCB / 1000C is determined according to the GPC and SCB test methods described below; wherein the 1-alkene comonomer is a 1-alkene (C4-C20) such as a 1-alkene (C4-C8) such as 1-butene, 1-hexene, or 1-octene. Linear low-density polyethylene or LLDPE. A poly(ethylene-co-l-alkene) copolymer having a density of 0.871 to less than 0.930 g / cm3, as measured according to ASTM D792-13; and having a significant amount of short-chain branching per 1000 carbon atoms (SCB / 1000C), where SCB / 1000C is determined according to the GPC and SCB test methods described below; wherein the 1-alkene comonomer is a 1-alkene (C4-C20) such as a 1-alkene (C4-C8) such as 1-butene, 1-hexene, or 1-octene. LLDPE is manufactured under different process conditions than LDPE. LLDPE has a different composition and certain superior properties that have led it to replace LDPE in many commercial applications. These include coatings, films, sheets, and injection-molded articles. LLDPE coatings include insulation layers for telecommunications cables. LLDPE films and sheets are used in both packaging and non-packaging applications. Examples include agricultural films, food packaging, garment bags, grocery bags, heavy-duty sacks, industrial sheets, pallets, shrink wrap, and bags. LLDPE injection-molded articles include buckets, freezer containers, lids, and toys. Liquid means an amorphous state of matter at room temperature (e.g., 23 °C) that is intermediate between a gas and a solid and has a stable volume, but not a definite shape. The term "liquid additive" is used to describe the state of matter of the additive at the temperature of the heterogeneous mixture during the acoustic energy application step. It does not necessarily require the additive to be liquid at room temperature (e.g., 23°C) if the temperature of the heterogeneous mixture during the acoustic energy application step is higher than room temperature. In some respects, the liquid additive is a liquid at room temperature (e.g., at 23°C). Solvents are not examples of liquid additives because solvents are simply used to dissolve a solid or liquid additive to bring it into contact with the polyolefin solids (A) and / or the organic peroxide (B). They are intended to be removed from the heterogeneous mixture after the contact step, or are subsequently removed from the homogeneous mixture before the homogeneous mixture is used to make a shaped article. cq Lznn / zznz / E / YiAi Maintaining the temperature of a material below a threshold value. Any passive or active means of preventing the material from reaching the threshold value. Passive maintenance means may include placing the material in a container (e.g., in an acoustic mixing device) where the container temperature is below the threshold value, and not exposing the container and its contents to a heat source. Active maintenance means may include thermally insulating the container or placing the container in effective cooling contact with a heat exchanger device that has a coolant circulating through it. Medium-density polyethylene or MDPE. A poly(ethylene-co-l-alkene) copolymer having a density of 0.930 to less than 0.940 g / cm3, measured according to ASTM D792-13; wherein the 1-alkene comonomer is a (C4-C20) 1-alkene such as a (C4-C20) 1-alkene such as 1-butene, 1-hexene, or 1-octene. Melting means changing a material from a solid state to a liquid state. Typically, melting means the change is complete, so the liquid state contains no unmelted solid form of the material. The temperature at which a material is characterized as either solid or liquid is 20 °C. Polyolefin means any macromolecule comprising constituent units derived from the polymerization of a monomer with olefin functionality or from the copolymerization of at least two monomers with olefin functionality, or a mixture of such macromolecules. Polyolefin may be amorphous (i.e., with a glass transition temperature but no melting point in differential scanning calorimetry (DSC)) or semicrystalline (i.e., with a glass transition temperature and a melting point in DSC). Solid means a state of matter at room temperature (e.g., 23 °C) that has a stable volume and a definite shape. It can be amorphous, crystalline, or semicrystalline. Any compound, composition, formulation, material, mixture, or reaction product herein may be free of any one of the chemical elements selected from the group consisting of: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Se, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Te, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Ti, Pb, Bi, lanthanides, and actinoids; provided that the chemical elements inherently required by the compound, composition, formulation, material, mixture, or reaction product (e.g., C and H required by a polyethylene or C, H, and O required by an alcohol) are not omitted. Alternatively, it may precede a different modality. ANSI is the American National Standards Institute organization, headquartered in Washington, D.C., USA. ASME is the American Society of Mechanical Engineers, headquartered in New York City, New York, USA. ASTM is the standards organization, ASTM International, West Conshohocken, Pennsylvania, USA. Any comparative examples are used for illustrative purposes and are not to be considered prior art. Free from or lacking means a complete absence of; alternatively, it means not detestable. IUPAC is the International Union of Pure and Applied Chemistry (IUPAC Secretariat, Research Triangle Park, North Carolina, USA). The Periodic Table of the Elements is the IUPAC version of May 1, 2018. May refers to a permitted option, not a requirement. Operative means functionally capable or effective.Optionally means absent (or excluded), or alternatively, present (or included). Properties can be measured using standard test methods and conditions. Intervals include endpoints, subintervals, and whole and / or fractional values ​​included in this description, unless an integer interval does not include fractional values. Ambient temperature: 23° ± 1°C. cq Lznn / zznz / E / YiAi Unless otherwise stated, the definitions of terms used in this document were taken from the IUPAC Compendium of Chemical Technology (Gold Book) version 2.3.3 dated 24 February 2014. Some definitions are described below for convenience. Density: Determined in accordance with ASTM D79213, Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement, Method B (for testing solid plastics in liquids other than water, e.g., in liquid 2-propanol). Units of grams per cubic centimeter (g / cm3). Melt flow index (12): determined in accordance with ASTM D1238-13, using conditions of 190 °C / 2.16 kg, formerly known as condition E. Units of grams per 10 minutes (g / 10 min.). EXAMPLES The additional inventive features are the foregoing aspects, and the claims described below, which describe a range for a process condition and / or a range for a material property, wherein in the additional inventive features an endpoint of the process condition range and / or an endpoint of the material property range, respectively, is modified to any exemplified process condition value and / or any exemplified material property value cq Lznn / zznz / E / YiAi, respectively, described below in this section for any inventive example. Polyolefin solids (A)-l: a low-density poly(ethylene-co-l-hexene) copolymer having a unimodal molecular weight distribution, a density of 0.92 g / cc and a melting index (12, 190 °C, 2.16 kg) of g / 10 min. (LDPE-1, 2 MI). It is used in the form of dry granules. Polyolefin (A)-2 solids (Prophetic): a low-density poly(ethylene-co-l-hexene) copolymer (LDPE-2) that has a density of 0.92 g / cc and a melting index (12, 190 °C, 2.16 kg) of 0.6 to 0.08 g / 10 min. It is used in the form of dry granules. Polyolefin (A)-3 solids (Prophetic): a low-density poly(ethylene-co-l-hexene) copolymer (LDPE-3) that has a density of 0.922 to 0.924 g / cc and a melting index (12, 190 °C, 2.16 kg) of 20 min. It is used in the form of granules. Polyolefin solids (A)-4 (prophetic): A linear low-density polyethylene (LLDPE-1) that is a poly(ethylene-co-l-butene) copolymer having a unimodal molecular weight distribution, a density of 0.92 g / cc, and a melt index (12, 190 °C, 2.16 kg) of 0.6 to 0.8 g / 10 min. It can be used in the form of dry pellets or dry beads. The beads can be obtained from a gas-phase polymerization reactor. The pellets are made from the reactor beads and are available as DFDA-7530 NT from The Dow Chemical Company. The pellets can be converted into beads by granulation. The beads were used in IE1 through IE4 (Table 1 below), and the pellets were used in the prophetic example IE9 (Table 2 below). Polyolefin (A)-5 (prophetic) solids: A medium-density polyethylene (MDPE-1) that is a poly(ethylene-co-l-hexene) copolymer having a unimodal molecular weight distribution, a density of 0.930 to 0.940 g / cc, and a melt index (12, 190 °C, 2.16 kg) of 0.7 to 0.9 g / 10 min. DFH-3580 of The Dow Chemical Company. Used in the form of dry granules. Organic peroxide (B)-l: dicumyl peroxide (DiCuP). Solid Antioxidant (C)-l: tris[(4-tert-butyl-3-hydroxy2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6-frione (TMTT). Solid antioxidant (C)-2: distearyl thiodipropionate (DSTDP). Solid stabilizer (D)-l: a solid thermal stabilizer that is N,N'-bisformyl-N,N'-bis(2,2,6,6-tetramethyl-4piperidinyl)-hexamethylenediamine (BBHMDA). Comparative Example 1 (CE1): Sample prepared by melt mixing (melt composition). In the conventional mixing process, the samples were prepared by first making intermediate formulations containing only the solid constituents of polyolefin (A)-1, antioxidant (C)-1, antioxidant (C)-2, and heat stabilizer (D)-1. The experiments were performed using a Brabender laboratory electric batch mixer with a preparation mixer / measuring head equipped with Cam blades. The ingredients were melted at 120 °C for 3 minutes. The resulting mixture was then flattened, cooled, and cut into strips. These were then fed into a single-screw extruder to make wire strands, which were then cut into granules. The unit consisted of a 1-inch BRABENDER extruder.A 9 cm (¾ in) extruder with a variable speed drive, a 24:1 Maddock mixing head screw, a BRABENDER strand die, a laboratory water cooling channel with a blow ring, a laser micrometer, and a variable speed extractor was set up. Samples were extruded at a screw speed of 40 revolutions per minute (rpm) and a collection rate of approximately 2.4 meters (8 feet) per minute. Strands were made using a set temperature profile of 150 °C / 170 °C / 190 °C / 195 °C (across zone 1, zone 2, zone 3, and head / die) followed by granulation at room temperature (e.g., 23 °C). Organic (B)-1 peroxide, extracted from a frozen sealed glass bottle, was placed inside a polyethylene bag and placed in a 60 °C water bath. The sample granules were preheated in a large glass jar at 70 °C for 4 hours. After preheating, the organic peroxide (B)-1 was pre-weighed to the specified amount and added to the granules using syringes. The jar of granules was then tightly sealed and placed in a stoneware drum set to 30 rpm. After 5 minutes of rotation, the drum was removed and the granules were manually shaken to loosen them from the sides of the jar. The organic peroxide soaking process continued for 8 to 10 hours at 70 °C. The formulation of CE1 is reported later in Table 1. Comparative Example 2 (CE2): made by physical mixing. A total of 150 g of the polyethylene pellets (A)-1 were brought into contact and physically mixed with the organic peroxide (B)-1 (which had been extracted from a frozen, sealed glass bottle) and the antioxidant additives (C)-1, (C)-2, and heat stabilizer (D)-1 in the quantities shown later in Table 1 to make CE2 as a physical mixture of (A)-1, (B)-1, (C)-1, (C)-2, and (D)-1. The CE2 was tested for curing properties, and the results are also shown in Table 1. The curing properties showed that the physical mixture of CE2 had not achieved crosslinking, i.e., it lacked crosslinking. Because there was no crosslinking, there was no reason to perform mechanical tests on CE2. Inventive Example 1 (IE1): An inventive example was carried out using acoustic mixing. A total of 150 g of polyethylene pellets (A)-1 were contacted with organic peroxide (B)-1, extracted from a frozen, sealed glass bottle, antioxidant additives (C)-1, antioxidant (C)-2, and heat stabilizer (D)-1 in the amounts shown in Table 1 to make a heterogeneous mixture of IE1. Acoustic energy was applied to the heterogeneous mixtures using a Resodyn™ Acoustic Mixer (LabRAM Mixer) at 23° to 26°C for 3 minutes in a glass jar at a frequency of 60 hertz (Hz) to separately make the homogeneous mixture of IE1. Multiple batches of the homogeneous mixture were prepared to obtain sufficient testing of the material properties and for extrusion onto wires. The homogeneous mixtures of the invention were extruded separately using a Brabender 1 extruder.9 cm (¾ inch), 25-1 L / D, with a Maddox mixer head screw, using a strand die. The extruder temperature profile was set to 150 °C / 170 °C / 180 °C / 190 °C and the screw speed was 40 rpm. The strands were granulated at room temperature for further processing to separately yield the homogeneous IE1 blend as granules. The formulation is reported later in Table 1. Test Methods for Curing Properties. Moving die rheometer analyses were performed on samples from IE1 and CE1 using the Alpha Technologies Rheometer MDR model 2000 unit. The tests were based on ASTM D5289-12, Standard Test Method for Vulcanizing Properties of Rubber Using Rotorless Curing Gauges. MDR analyses were performed using 4 to 5 grams of material. Samples were tested at 182 °C for 15 minutes with an arc oscillation of 0.5 degrees, while monitoring the change in torque. Designate the lowest measured torque value as “ML,” expressed in deciNewton-meters (dN-m). As curing or cross-linking progresses, the measured torque value increases, eventually reaching a maximum torque value. Designate the maximum or highest measured torque value as “MH,” expressed in dN-m.All other things being equal, the greater the torque value MH, the greater the degree of cross-linking. Determine the total amount of cross-linking as the difference MH minus ML (MH - ML). The greater the difference MH - ML, the greater the amount of cross-linking. Measured in inch-pounds (lb.in.), and converted to Newton-meters (Nm), where 1.00 lb.in. = 0.113 Nm. Mechanical Properties Test Methods. Compression-molded plates were prepared from the CE1 comparative mix and the IE1 homogeneous mix for use as specimens for final tensile strength and elongation at break (T&E) tests. The granulated homogeneous mixes were compression-molded separately using a WABASH Steam Genesis press (with rapid cooling capability) operated in manual mode. The press was preheated to 115° ± 5°C. A total of 75 grams of granules were pre-weighed and placed in the center of a 1.9 mm (75 mils) stainless steel plate between the mold assembly composed of mylar and aluminum sheets. The resulting filled mold was then placed in the press at 2.1 megapascals (MPa, 300 pounds per square inch (psi)) for 3 minutes. After this initial pressure, the temperature was increased to 185° ± 5 °C for 2 minutes. Then the pressure was increased to 17.2 MPa (2500 psi) for 15 minutes.The vapor-to-water change occurred 15 seconds before the end of the 15-minute period, and the samples were rapidly cooled for 5 minutes. The cooled samples were extracted after reaching 35 °C to yield compression-molded IE1 and CE1 plates (dimensions 0.20 x 0.20 x 1.9 mm (8 x 8 x 75 mils)). Three IE1 and three CE1 plates were produced. Five Type IV dog bone shapes were cut from the plates and subjected to tensile testing according to ASTM D63803 after being conditioned for 48 hours in a controlled air atmosphere at 23.0 °C (73.4 degrees). Fahrenheit (°F) with 50% relative humidity. Tensile strength and elongation at break tests were performed on an Instron Renew 4201 65 / 16 apparatus using a jaw separation speed of 50.8 cm per minute (20 inches per minute) with a 45-kilogram (100-lb) load cell. Mechanical property tests were performed on compression-molded plate samples that were not heat-aged and on samples after heat aging. The higher the tensile strength value, the greater the maximum amount of stress a material can withstand without stretching or breaking. The lower the elongation at break value, the less stretching a test material can undergo before breaking. The data are reported below in Table 1. Table 1: Homogeneous mixtures and properties of the examples. Homogeneous Mixtures (% by weight) (composed by melt / soaked or acoustically blended) CE1* CE2 IE1L Polyolefin Solids (A)-1 (LLDPE-1, 2 MI) 97.93 97.73 97.73 Solid Organic Peroxide (B)-1 (DiCuP) 1.8 1.8 1.9 Solid Antioxidant (C)-1 (TMTT) 0.14 0.14 0.14 Solid Antioxidant (C)-2 (DSTDP) 0.23 0.23 0.23 Solid Stabilizer (D)-1 (BBHMDA) 0.006 0.006 0.006 Total (% by weight) 100.0 100.0 100.0 Curing properties MH, Nm (lb-in) 0.36 (3.2) 0.022 (0.2) 0.38 (3.4) ML, Nm (lb-in) 0.05 (0.4) 0.018 (0.16) 0.03 (0.3) MH-ML, Nm (lb-in) 0.31 (2.8) 0.004 (0.04) 0.35 (3.1) Mechanical properties Tensile strength, MPa (psi) (without heat aging) 22.3 (3230) N / m 20.4 (2960) Elongation at break (%) (without heat aging) 559 N / m 506 N / m not measured. N / a not applicable. N / r not reported. As shown by comparing the IE1 data with the CE1 data in Table 1, these mechanical and curing property characterizations show that the homogeneous mixture of the invention can be prepared quickly (in less than 10 minutes, e.g., 3 minutes) at moderate temperatures (e.g., <30 °C, e.g., from 23 °C to 26 °C) and achieve the organic peroxide (B) loading levels that are normally used for curing polyolefins.Furthermore, the homogeneous mixture of the invention can be cured to give curing and mechanical properties that are improved with respect to those obtained from a comparative example made by a conventional two-step process comprising melt-mixing the polyolefin solids with all additives (except organic peroxide) at 120 °C to give an intermediate mixture, then extruding strands of this at 150 °C / 170 °C / 190 °C / 195 °C, granulating and soaking organic peroxide in the granules at elevated temperature (70 °C) for a prolonged period of time (8 to 10 hours).In fact, as indicated by a lower initial ML value and a higher final MH value (MH - ML) obtained by curing the homogeneous mixture of the invention using a moving die rheometer, it can be concluded that the acoustic mixing method of the invention reduces the decomposition of organic peroxide during the preparation of the homogeneous mixture of the invention compared to the preparation of the comparative melt / soak mixture. As a result, a higher degree of crosslinking of the homogeneous mixture of the invention is also achieved compared to the comparative melt / soak mixture. This inventive advantage is also reflected in the inventive cured product, which has a lower elongation at break (i.e., greater crosslinking) than the comparative cured product. As the data for CE2 in Table 1 show, mechanical testing was not performed on CE2 because the curing properties of the samples showed a lack of crosslinking. This result for CE2 demonstrates that a comparative method comprising mechanically or physically mixing polyolefin solids (A) and organic peroxide (B) without melting the polyolefin solids (A) or allowing time for the organic peroxide (B) to penetrate the unmelted polyolefin solids (A) is a challenge that is overcome by the present method, which comprises applying acoustic energy to achieve acoustic mixing. (Prophetic) Manufacturing a coated conductor. The homogeneous granulated mixture of the invention, IE1, is fed into a wire coating extrusion line to make a coated wire having a coating consisting essentially of IE1, or a crosslinked product made by curing it, as wire constructs on 14 AWG solid copper wire. The wire coating extrusion line comprises a 1.9 cm BRABENDER extruder with variable speed drive, a standard 25:1 PE screw, a BRABENDER crosshead wire die, a laboratory water cooling channel with blow ring, a laser micrometer, and a variable speed wire extractor. The sample is extruded at a screw speed of 40 rpm with a wall thickness of 0.76 millimeters (mm, 30 mils).A wire is manufactured using a set temperature profile of 160°C / 170°C / 180°C / 190°C in zone 1 / zone 2 / zone 3 and die / head, respectively, at a pickup rate of 3.1 meters per minute (10 feet per minute). The wire coating consists essentially of a homogeneous mixture of IE1 and a crosslinked curing product. If desired, the wire can be passed through a vulcanization tube set to a curing temperature of 220°C to fully cure the homogeneous mixture, resulting in a wire with a coating, where the coating consists essentially of a crosslinked IE1 product. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

1. A method for making a homogeneous mixture of polyolefin solids and organic peroxide without melting the polyolefin solids during manufacture, characterized in that it comprises applying acoustic energy at a frequency of 20 to 100 hertz (Hz) to a heterogeneous mixture comprising polyolefin solids (A) and organic peroxide (B) for a period of time sufficient to substantially intermix the polyolefin solids (A) and the organic peroxide (B) while maintaining the temperature of the heterogeneous mixture (and, for that matter, the temperature of the homogeneous mixture made therefrom) below the melting temperature of the polyolefin solids (A), thereby making the mixture homogeneous without melting the polyolefin solids (A); wherein the polyolefin solids (A) are from 95.0 to 99.9 percent by weight (% wt) and the organic peroxide (B) is from 0.1 to 5.0% by weight, respectively, of the combined weights of constituents (A) and (B).

2. The method according to claim 1, characterized in that the acoustic energy application step is characterized by any one of the limitations (i) to (v): (i) the frequency is from 50 to 70 Hz; (ii) the time period is from 0.5 minutes to 4 hours; (iii) both (i) and (ii); (iv) maintaining the temperature of the heterogeneous mixture below the melting temperature of the polyolefin solids (A) comprises maintaining the temperature of the heterogeneous mixture between -20 °C and 109 °C; and (v) both (iv) and any one of (i) to (iii).

3. The method according to claim 1 or 2, characterized in that the polyolefin solids (A) are characterized by a physical form (i.e., a solid particle form) that is a powder, pellets, granules, or a mixture of any two or more of these, and by a melting temperature that is from 61° to 180°C; and the organic peroxide (B) is a liquid organic peroxide or a solid organic peroxide.

4. The method according to any one of claims 1 to 3, characterized in that the polyolefin of the polyolefin solids (A) consists essentially of one or more ethylene-based polymers; wherein each ethylene-based polymer is a low-density polyethylene (LDPE) polymer or a combination of the LDPE polymer and a polyolefin selected from the group consisting of: a second LDPE polymer; a linear low-density polyethylene polymer; and a high-density polyethylene polymer. In other embodiments, the polyolefin of the polyolefin solids (A) consists essentially of an LDPE and a polypropylene polymer.

5. The method according to any of claims 1 to 4, characterized in that the organic peroxide is a solid organic peroxide.

6. The method according to any of claims 1 to 5, characterized in that the heterogeneous mixture further comprises one or more additives other than the polyolefin solids (A) or the organic peroxide (B), and the acoustic energy application step comprises applying acoustic energy at a frequency of 20 to 100 hertz (Hz) to the heterogeneous mixture comprising the polyolefin solids (A), the organic peroxide (B) and the one or more additives other than a peroxide for a period of time sufficient to substantially intermix (wholly or completely homogenize) the polyolefin solids (A), the organic peroxide (B) and the one or more additives together while maintaining the temperature of the heterogeneous mixture below the melting temperature of the polyolefin solids (A), thereby making the mixture homogeneous, further comprising the one or more additives, without melting the polyolefin solids (A).

7. The method according to claim 6, characterized in that at least one of the one or more additives other than constituents (A) or (B) is independently a liquid additive or a solid particulate additive selected independently of additives (C) to (D): a liquid or solid particulate antioxidant (C); and a liquid or solid particulate stabilizer (D) for stabilizing the homogeneous mixture against the effects of ultraviolet light and / or heat.

8. The method according to claim 7, characterized in that the one or more additives include one or more of the solid antioxidant (C)-1: tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6-phryone; solid antioxidant (C)-2: distearyl thiodipropionate; and solid stabilizer (D)-1: N,N'-bisformyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-hexamethylenediamine.

9. The method according to any of claims 1 to 8, characterized in that it further comprises, prior to the acoustic energy application step, a step of melting the polyolefin solids (A) to make a melt thereof, and mechanically mixing the melt of (A) with one or more additives other than organic peroxide (B) to give a melt free of organic peroxide (B); shaping the melt to give a shaped melt; and cooling the shaped melt to give polyolefin solids (A) containing one or more additives; and combining the polyolefin solids (A) containing one or more additives with the organic peroxide (B) to give the heterogeneous mixture.

10. The method in accordance with any of claims 1 to 9, characterized in that it further comprises curing the homogeneous mixture to give a homogeneous crosslinked product.