BR112020024826B1 - METHOD FOR RECYCLING A FIRST POLYMER FROM A MULTICOMPONENT POLYMER PRODUCT, AND, RECYCLED POLYMER COMPOSITION - Google Patents

Abstract

A method for recycling a first polymer from a multicomponent polymer product may include subjecting the multicomponent polymer product that includes a first polymer and at least one additional component to conditions to melt the first polymer; and filtering the at least one additional component of the first polymer melt.

Description

FUNDAMENTALS

[001] A wide variety of products are manufactured from thermoplastic composites or multicomponent materials. These products often comprise several polymers or polymers and inorganic material, which may be present in distinct phases and which may be referred to as multilayer or blended systems or products. The adaptable polymer/polymer or polymer/inorganic material combination is directly dependent on the desired function of the final product. Laminate materials, produced by a lamination process, are often engineered to have particular barrier properties that can be provided by combining layers of different polymers. Typically, polyolefin polymers, such as polyethylene (PE) and polypropylene (PP), can be used to manufacture a wide range, including films, molded products, foams and the like. In multicomponent systems, particularly laminated systems, polymers can often be combined with or manufactured to comprise aluminum or other inorganic materials, as well as to achieve the specific barrier characteristics desired.

[002] Polyolefins can have characteristics such as high processability, low production cost, flexibility, low density and possibility of recycling. However, physical and chemical properties of polyolefin compositions may exhibit varying responses depending on a number of factors such as molecular weight, molecular weight distribution, comonomer (or comonomers) content and distribution, processing method, and the like.

[003] Common methods for manufacturing multicomponent polymer systems include, but are not limited to, extrusion, coextrusion and lamination processes. Extrusion or coextrusion is a process where one or more polymers are fed through a special die and the molten polymer fluids are contained in a molten state. The resulting multicomponent compositional characteristics are dependent on the extrusion process parameters. Notable parameters include, but are not limited to, the melting temperature and viscosity of the liquid polymer. Adhesive lamination is another common production process that differs from extrusion in that it is used to manufacture distinct layer compositions through physical adhesion to one or more polymer films in which the adhesion process is facilitated under specific chemical, temperature and and pressure.

[004] These multicomponent polymer production methods can utilize limited inter- and intramolecular interactions of the polyolefin, capitalizing on the high degree of freedom in the polymer to form different monostructures and to modify the multipolymer composite to obtain the product. Consequently, where recycling processes have the potential to convert laminated or composite materials into useful raw materials, there may be times when the basic incompatibility of the polymers in the recyclable product leads to the production of inhomogeneous blends that have unacceptable physical properties. This incompatibility often arises with the result of poor layer-layer interaction between the polar and non-polar polymeric phases. This can result in a recycled product that may exhibit low mechanical strength and poor optical transparency. Multicomponent products are often difficult to recycle in that final post-consumer product mixtures often require a separation of the polymeric components. These separation processes typically include mechanical separation or chemical separation or a mixture of the two.

SUMMARY

[005] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify principal or essential features of the claimed subject matter, nor is it intended to be used as an aid to limiting the scope of the claimed subject matter.

[006] In one aspect, the embodiments described herein are directed to a method for recycling a first polymer from a multicomponent polymer product comprising subjecting the multicomponent polymer product comprising a first polymer and at least one additional component to conditions for melting the first polymer; and filtering the at least one additional component of the first polymer melt.

[007] In another aspect, embodiments of the present disclosure are directed to a method for recycling a first polymer from a multilayer polymer product, comprising subjecting the multilayer polymer product comprising the first polymer and at least one layer of inorganic material to conditions for melting the first polymer; and filtering the at least one inorganic material from the first polymer melt.

[008] In another aspect, embodiments of the present disclosure are directed to a method for recycling a non-polar polymer from a multilayer polymer product that includes subjecting the multilayer polymer product, the multilayer polymer product comprising a plurality of polymer layers , the plurality of polymer layers including polar polymer layers and non-polar polymer layers, to conditions for melting the multilayer polymer product and forming polar polymer particles dispersed in a continuous phase comprising the non-polar polymer; and at least partially filtering the dispersed polar polymer from the continuous phase.

[009] In another aspect, embodiments of the present description are directed to a method for recycling a non-polar polymer from a multilayer polymer product, comprising: subjecting the multilayer polymer product, the multilayer polymer product comprising a plurality of layers of polymer, wherein the plurality of polymer layers includes at least one layer of the non-polar polymer and at least one layer of the polar polymer, conditions for fusing the non-polar polymer and the polar polymer; selectively cross-link the polar polymer; and filtering the selectively cross-linked polar polymer from the molten non-polar polymer.

[0010] In yet another aspect, embodiments of the present disclosure are directed to a recycled polymer composition comprising the first filtered polymer or the filtered continuous phase produced by the method described in the above embodiments.

[0011] Other aspects and advantages of the claimed subject matter will be evident from the following description and the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a heat DSC curve.

[0013] Figures 2A-2B are heat DSC curves.

[0014] Figures 3A and 3B show SEM images.

[0015] Figure 4 is a heat DSC curve.

[0016] Figures 5A and 5B show heat DSC curves.

[0017] Figures 6A and 6B show SEM images.

DETAILED DESCRIPTION

[0018] Embodiments of the present disclosure are directed to a method for recycling multicomponent polymer products containing a mixture of polymer and inorganic material or multiple polymers. In particular, embodiments of the present disclosure are directed to selectively filtering one polymer component of the multicomponent polymer product, thereby allowing physical separation of at least one other component thereof.

[0019] In the present description, the terms “multicomponent polymer product”, “multilayer” polymer product, “laminated” and “coextruded multilayer product” are used. As used herein, a multicomponent polymer product refers to a polymer product that contains multiple components (at least one of which is a polymer component), which may include a blended product or a multilayer product. A polymer product may be in the form of a layered structure (as compared to a blended product, which may include multiple components, i.e., polymers, within a single layer or structure), wherein each layer may have a distinct composition . Such a layered structure may include laminates or coextruded multilayer products. Laminates refer to a multilayer product that is formed from two layers that are separately formed and then joined together by pressing, heating and/or adhesion. Laminates may include multiple polymeric layers or a combination of polymeric or inorganic layers. In contrast, a coextruded multilayer product (such as a multilayer film) refers to a product that has several distinct compositional layers, but which are formed in an extrusion or coextrusion process. Specifically, for example, several polymers can, in a molten state, be fed to a paint that extrudes several polymer layers within a single film, so that delamination (even at the edges) is not observed. Additionally, it is also contemplated that a multilayer polymer product may include a laminate with a multilayer coextruded film.

[0020] In each of such products, there are several components present, making recycling the product difficult. However, embodiments of the present disclosure utilize recycling processes that selectively address the different components, such as by selective melting, selective cross-linking, etc., so that one or more of the components can be separated from them. In one or more embodiments, the additional component may be removed from the first polymer so that the recycled polymer composition has at least a 50% reduction in the amount of the additional component contained therein, or at least a 60%, 70%, 80%, 90% reduction. %, 95%, 99% or 100% in the amount of additional component contained therein.

[0021] One or more embodiments are directed to recycling a laminate of at least one polymeric layer (whether polar or non-polar) and a layer of inorganic material. Thus, one or more embodiments may include subjecting the multilayer polymer product (laminate) comprising a polymeric layer of a first polymer and at least one layer of inorganic material to conditions that can selectively melt (in an extruder, for example) the first polymer and subsequently filtering the at least one inorganic material from the first molten polymer. It is understood that, depending on the feed source, such a multilayer polymer product may be subjected to a size reduction step (discussed in more detail below) prior to adding the multilayer polymer product to the extruder. Additionally, as discussed below, one or more inert components may be added to the extruder to assist in separating the first polymer and inorganic material/filtering the inorganic material therefrom.

[0022] One or more embodiments are directed to recycling a multicomponent polymer product that contains at least two polymeric components: one being nonpolar and the other being polar. In some embodiments, the multipolymer product containing at least two polymeric components may be a multilayer product (including a laminate or a coextruded multilayer product) or a blend of several polymeric components. In accordance with embodiments of the present disclosure, the multicomponent polymer product containing at least two polymeric components (in particular, one or more non-polar polymer layers and one or more polar polymer layers) may be subjected to conditions that melt the polymeric components , allowing coalescence of polar polymers to form polar polymer particles dispersed in a continuous nonpolar polymer phase. The dispersed polar polymer can be at least partially filtered from the continuous phase (non-polar polymer). This filtration can occur using selection of process temperatures used in filtration so that the polymer can coalesce into dispersed particles in a continuous phase and then be in time reduced to a temperature that is between the melting temperature of non-polar polymers (Tm plus high) and the melting temperature of polar polymers (lower Tm) so that the two can be separated from each other. Cross-linking may be optional in such embodiments, but it is specifically envisioned that filtration may occur without cross-linking, wherein “solid” polar polymer particles are separated from a molten continuous phase based on the temperature reduced during the filtration step.

[0023] In accordance with embodiments of the present disclosure, the multicomponent polymer product containing at least two polymeric components may be subjected to conditions that melt the polymeric components, allowing coalescence of the polar polymer into particles having a desirable particle size within the non-polar polymer matrix (or continuous phase) and subsequently selectively cross-linking the polar polymer particles within the non-polar polymer matrix (including, but not limited to, a polyolefin). The polar polymer can be cross-linked by a cross-linking agent to generate particulates containing intraparticle covalent bonds between the constituent polar polymer chains. Depending on the relative proximity of adjacent polar polymer particles (and concentration), it is also recognized that there may also be interparticle covalent bonds that are formed. The cross-linking of the polar polymer particles allows a morphological “freezing” of the particles, therefore reducing the possibility of deformation and allowing their retention by the mesh screen, otherwise unlikely to happen, as the polar polymer particles would deform and pass through the mesh. It is anticipated that even a partial cross-linking of the polar polymer particles (as a core-shell structure, for example, when the shell is cross-linked and the core is not) may be sufficient to achieve this effect. Extrusion conditions can be tuned to provide for formation of larger particles in the non-polar polymer melt, with a low degree of dispersion and low interaction between the polar and non-polar polymers.

[0024] As mentioned above, and as discussed in detail below, in some embodiments, an inert component may be injected into the extruder. The inert component may be one that is capable of swelling one or more of the polymers within the multicomponent system, for example. The addition of the inert component can aid the filtration process, increasing the hydrodynamic volume of the molten polymer phase and effectively decreasing interactions between the molten phase and cross-linked polar polymer particles and between polymers and inorganic materials.

[0025] The components present in the multicomponent polymer product, as well as components or materials used in the present recycling methods are discussed in turn. Non-polar polymers

[0026] One or more embodiments of the present description may include non-polar polymers, such as polyolefins may desirably be recycled from a multicomponent polymer product. Depending on the shape of the multicomponent polymer product. It is understood that the non-polar polymer may form a polymer layer, a matrix phase or even a disperse phase in the multicomponent polymer product. Nonpolar polymers are polymers that are incompatible or poorly compatible with polar polymers. In one or more embodiments, the non-polar polymers may include polyolefins, polystyrene, rubbers, or combinations thereof.

[0027] In one or more embodiments, polyolefins include polymers produced from unsaturated monomers (olefins or “alkenes”) with the general chemical formula of CnH2n. In some embodiments, polyolefins may include ethylene homopolymers, copolymers of ethylene and one or more C3-C20 alpha-olefins, propylene homopolymers, heterophasic propylene polymers, propylene copolymers, and one or more selected comonomers of ethylene and C4 alpha-olefins. -C20, olefin terpolymers and high order polymers, and blends obtained from mixing one or more of these polymers and/or copolymers. In one or more embodiments, polyolefins may include polyolefins generated from petroleum-based monomers and/or bio-based monomers, such as ethylene obtained by dehydration of bio-based alcohols derived from sugar cane. Commercial examples of biobased polyolefins are the polyethylenes from the “I’m Green”™ line from Braskem S.A.

[0028] Rubbers according to the present description may include one or more natural rubbers, polyisoprene (IR), styrene butadiene rubber (SBR), polybutadiene, nitrile rubber (NBR); polyolefin rubbers, such as ethylene propylene rubbers (EPDM, EPM) and the like, chlorinated butyl rubber, brominated isotubilene, polychloroprene and the like; sulfur-containing rubbers such as polysulfide rubber; fluorinated rubbers; thermoplastic rubbers, such as elastomers based on styrene, butadiene, isoprene, ethylene and propylene, styrene-isoprene-styrene (SIS), styrene-ethylene-butylene-styrene (SEBS), styrene-butylene-styrene (SBS) and the like.

[0029] In one or more embodiments, multicomponent polymer products may contain a percentage by weight of the total composition (% by weight) of non-polar polymer ranging from a lower limit selected from one of 30% by weight, 40% by weight, 50% by weight, 60% by weight, 75% by weight and 85% by weight, up to an upper limit selected from one of 60% by weight, 75% by weight, 80% by weight, 90% by weight, 95% by weight, 99.5% by weight and 99.9% by weight, where any lower limit may be used with any upper limit. Additionally, in a recycled polymer composition, it is anticipated that the recycled polymer composition may contain a weight percentage of the total composition (wt%) ranging from a lower limit of 30 wt%, 40 wt%, 50% by weight, 60% by weight, 75% by weight and 85% by weight, up to an upper limit of 60% by weight, 75% by weight, 80% by weight, 90% by weight, 95% by weight, 99.5% by weight and 99.9% by weight, where any lower limit can be used with any upper limit. Where the additional component is filtered from a non-polar polymer, it is anticipated that the recycled polymer composition may contain a weight percentage of the total composition (wt%) ranging from a lower limit of 60% by weight, 75% by weight. weight, 85% by weight, 90% by weight, 95% by weight, 99% by weight up to an upper limit selected from one of 60% by weight, 75% by weight, 80% by weight, 90% by weight, 95 % by weight, 99.5% by weight, 99.9% by weight, and 100% by weight, where any lower limit may be used with any upper limit. Polar polymers

[0030] The multicomponent polymer products of the present disclosure may include one or more polar polymers that are combined with the nonpolar polymer (including, but not limited to, polyolefins) in the multicomponent product, as a blend or multilayer structure, so that the present methods can be used to separate materials from each other. According to the present recycling methods, the polar polymer can be cross-linked during such recycling by one or more cross-linking agents. As used herein, a “polar polymer” is understood to be any polymer containing hydroxyl, carboxylic acid, carboxylate, ester, ether, acetate, amide, amine, epoxy, imide, imine, sulfone, phosphone and their derivatives as functional groups, among others. . The polar polymer may be selected from the group consisting of polyvinyl alcohol (PVOH), ethylene vinyl alcohol copolymer (EVOH), ethylene-vinyl acetate copolymer (EVA) polymer, polyamide, poly(vinylidene fluoride), poly(terephthalate) ethylene) and mixtures thereof. The polar polymer can be selectively cross-linked by a suitable cross-linking agent, wherein selective cross-linking can occur between the functional groups by reacting with a suitable cross-linking agent in the presence of polyolefins, additives and other materials. Thus, the cross-linking agent is selected to react with the polar polymer, but without exhibiting reactivity (or having minimal reactivity) with the non-polar polymer.

[0031] In one or more embodiments, the polar polymer to be removed from the recycled polymer composition, the polar polymer may form distinct phases during the extrusion process to form particles having an average particle size greater than 15 μm, 30 μm, 50 μm, 100 μm, 200 μm or 300 μm, depending on the size of the mesh screen incorporated in the extruder.

[0032] In one or more embodiments, the polar polymer particles are a semicrystalline polymer. In some embodiments, the conditions for melting the polar polymer (into a multilayer polymer product) involve subjecting the multilayer polymer product to a temperature higher than the highest melting temperature (Tm) detectable on a DSC curve of the polymer product. multilayer.

[0033] In one or more other embodiments, the polar polymer particles are amorphous. In such embodiments, the conditions for melting the polar polymer (into a multilayer polymer product) involve subjecting the multilayer polymer product to a temperature at least 50°C higher than the highest glass transition temperature (Tg) detectable in a DMA curve of the multilayer polymer product. Cross-linking agent

[0034] In one or more embodiments, a crosslinking agent can be used to crosslink a selected polymeric phase in a recycling stream. As used herein, a “crosslinking agent” is understood to mean any bi- or multifunctional chemical substance capable of selectively reacting with polar groups of a polymer, forming crosslinks between and within the constituent polymer chains. As used herein, “selectively” or “selectively” used alone or in conjunction with “cross-linking” or “cross-linked” is used to specify that the cross-linking agent reacts exclusively with the polar polymer, or that the cross-linking agent reacts with the polar polymer polar to a substantially greater degree (98% or more, for example) than with respect to the non-polar polymer. In one or more embodiments, crosslinking agents with three or more functional groups can be used.

[0035] In one or more embodiments, crosslinking agents according to the present description may include linear, branched, saturated and unsaturated carbon chains containing functional groups that react with counterpart functional groups present in the main chain and termini of a polar polymer incorporated into a polymer composition. In some embodiments, crosslinking agents may be added to a multicomponent polymer product containing a nonpolar polymer and a polar polymer, prior to melting the polymer product, in order to crosslink the polar polymer in the presence of the nonpolar polymer within. an extruder into which the combination was added. It is also anticipated that the crosslinking agent may be injected into the extruder after adding the multicomponent polymer product thereto. Following addition thereto, a cross-linking agent may react with the polar polymer within the particles, creating intraparticle cross-links between the polar polymer chains.

[0036] Crosslinking agents according to the present description may include, for example, maleic anhydride, maleic acid, itaconic acid, itaconic anhydride, succinic acid, succinic anhydride, succinic aldehyde, adipic acid, adipic anhydride, phthalic anhydride, phthalic acid , citric acid, glutaconic acid, glutaconic anhydride, glutaraldehyde, sodium tetraborate, organic titanates such as tetrabutyl titanate, organic zirconates such as zirconium(IV) bis(diethyl citrate)dipropoxide, methoxy polyethylene glycol acrylates, ethoxy polyethylene glycol acrylates, ethylene glycol diacrylate, ethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, trimethylol ethane triacrylate, trimethylol ethane trimethacrylate, trimethylol ethane triacrylate trimethylol propane, trimethylol propane trimethacrylate and tetramethylol methane tetraacrylate, their derivatives and mixtures thereof.

[0037] In one or more embodiments, crosslinking agents may be added to the multicomponent polymer product (or within an extruder containing such multicomponent polymer product) at a weight percentage (wt%) of the blend ranging from a lower limit selected from one of 0.001% by weight, 0.01% by weight, 0.05% by weight, 0.5% by weight, 1% by weight and 2% by weight up to an upper limit selected from one of 1.5 % by weight, 2% by weight, 5% by weight, and 10% by weight, where any lower limit may be used with any upper limit. Inorganic material

[0038] As mentioned above, one or more embodiments use an inorganic material in a multicomponent polymer product that contains the inorganic material as well as at least one polymer (which may be a non-polar polymer, such as a polyolefin or a polar polymer, including those described above). In one or more embodiments, the inorganic material may include metals, for example, copper, aluminum, nickel and steel or a mixture thereof. Furthermore, it is also anticipated that the inorganic material can be used with various polymers, including, for example, a polyolefin and a polar polymer, various non-polar polymers and various polar polymers).

[0039] The inorganic material to be removed from the recycled polymer composition may be present during the extrusion process in the form of particles, flakes, granules or any other form of small particle size. Inorganic particles may be present in the recycled polymer composition with a particle size greater than 30 µm, 50 µm, 100 µm, 200 µm or 300 µm, in at least one of three dimensions, depending on the size of the mesh screen incorporated into the extruder. Inert component

[0040] In one or more embodiments of the present description, an inert component can be injected or applied to the extrusion process. The inert component may be one that is capable of swelling one or more of the polymers (particularly the non-polar polymer or other polymer from which a polar polymer or inorganic material is being separated therefrom) within the multicomponent system, thereby aiding separation. of non-swollen cross-linked polar polymer particles or inorganic material. Additionally, the inert component can also reduce the overall viscosity of the polymer melt, allowing the polymer matrix to flow more easily through a filter or screen within the extruder, leaving additional material (such as inorganic material or selectively cross-linked polymer particles) behind. retained on a screen. The inert component may be in a gaseous, liquefied, or supercritical state and, in one or more embodiments, may be selected from a group consisting of CO2, N2, water, organic solvents, and combinations thereof, as well as other inert components. , which will eventually be separated from the molten polymer by a degassing step. It is also contemplated that the inert component may be produced by decomposition of a blowing agent during extrusion of the recycled polymer composition, which may be added together with or separate from the multicomponent polymer product in the extrusion.

[0041] In one or more embodiments, the inert component may be injected in an amount ranging from 0.5 to 20% by weight (of the multicomponent polymer product), including a lower limit of any of 0.5, 1, 1 5, 2, 5 or 10% by weight and an upper limit of 5, 8, 10, 12, 15, 18 or 20% by weight, where any lower limit may be used in combination with any upper limit.

[0042] Blowing agents that can be injected or fed to the extruder can be selected from organic or chemical blowing agents. Organic solvent blowing agents include aliphatic hydrocarbons having 1-9 carbon atoms, halogenated aliphatic hydrocarbons having 1-4 carbon atoms, and aliphatic alcohols having 1-3 carbon atoms. Aliphatic hydrocarbons include methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane and the like. Among the halogenated hydrocarbons, fluorinated hydrocarbons are preferred. Examples of fluorinated hydrocarbons include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC -134a), pentafluoroethane, perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, perfluorobutane, perfluorocyclobutane. Partially halogenated chlorocarbons and chlorofluorocarbons for use in this invention include methyl chloride, methylene chloride, ethyl chloride, 1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1 ,1-difluoroethane (HCFC-142b), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124). Fully halogenated chlorofluorocarbons include trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane, and dichlorohexafluoropropane. Fully halogenated chlorofluorocarbons are not preferred due to their ozone depletion potential. Aliphatic alcohols include methanol, ethanol, n-propanol and isopropanol.

[0043] Chemical blowing agents include azodicarbonamide, azodi-isobutyro-nitrile, benzenesulfonhydrazide, 4,4-oxybenzene sulfonylsemicarbazide, p-toluene sulfonyl semicarbazide, barium azodicarboxylate, N, N'-dimethyl-N, N'- dinitrosoterephthalamide and trihydrazine triazine.

[0044] In one or more embodiments, the blowing agents may include citric acid, succinic acid, sulfonyl benzene hydrazine, sulfonyltoluene semicarbazide, 5-phenyl tetrazole, sodium bicarbonate and calcium carbonate.

[0045] It is also anticipated that, in addition to the components described above, the multicomponent polymer product may also contain optional materials, such as conventional additives used in polymeric materials, including plasticizers, stabilizers, including viscosity stabilizers and hydrolytic stabilizers, antioxidants, absorbers ultraviolet rays, antistatic agents, dyes, pigments or other coloring agents, inorganic fillers, fire retardants, lubricants, reinforcing agents such as glass fiber and flakes, foaming agents, processing aids, antiblocking agents, release agents and /or mixtures thereof. Fusion filtering

[0046] Multicomponent polymer products according to the present description can be recycled by forming a polymer melt and filtering one or more additional components of the multicomponent polymer product therefrom. It is also anticipated that when the multicomponent polymer product contains multiple polymers with at least one polar polymer and at least one nonpolar polymer, that the polymer components can be fused under conditions where the polar polymer coalesces, forming large particles. During the fusion process, the dispersed polar phase tends to coalesce due to thermodynamic energies. As the viscosity ratio between the polar and non-polar phases increases, there is a greater tendency for coalescence to occur, which leads to an increase in the size of the dispersed polar polymer particles, sufficient to be retained on a screen during filtration. . Polar polymer particles can be selectively cross-linked to form cross-linked polar polymer particles, “freezing” the morphology of such particles. Selectively cross-linked polar polymers can be filtered from the molten continuous phase comprising the non-polar polymer. Filtration may occur through any screen or filter, such as a continuous exchange screen or any melt filtration system known in the art.

[0047] The first polymer of the multicomponent polymer product can be melted in an extrusion process, such as with a single, twin or multi-screw extruder. The use of melt filtration can allow purification of the first polymer to specified standards to form a recycled polymer composition that can have subsequent use, while minimizing the presence of impurities, such as incompatible inorganic materials and/or polar polymers. Furthermore, it is understood that melt filtration can occur in a single step or in multiple steps, for example. It is specifically envisioned that melt filtration may occur (i) in single extrusion, where melting (and optionally cross-linking) and filtering occur in a single extrusion step; or (ii) in double extrusion, where, in the first extrusion, melting (and optionally cross-linking) occurs while filtering occurs in a second extrusion step. Based on the present description, it may be apparent to one skilled in the art that, between the two extrusion steps, the material formed after the first extrusion step can be pelletized to be fed into the second extrusion step.

[0048] In one or more embodiments, the extruder can be used at temperatures ranging from 70°C to 320°C in some embodiments and from 150°C to 320°C in other embodiments and at shear rates of less than 1000 s -1 and pressures from 0.5 MPa to 20 MPa (5 to 200 bar). In embodiments in which the multicomponent polymer product includes a polar polymer as well as a nonpolar polymer, the multicomponent polymer product may be melted and the polar polymer under conditions where the polar polymer coalesces, forming polymer particles of a desirable size. of particle and one or more cross-linking agents can be used to allow the formation of a low-strain particulate morphology by cross-linking these polar polymer particles. Furthermore, embodiments of the present disclosure may also select extrusion conditions so as to result in relatively poor mixing (and dispersion of the polar polymer) and thus encourage the formation of cross-linked polar polymer particle sizes that can be sieved or filtered. of the molten polymer (e.g. greater than 30 microns, for example). Reducing interactions between the cross-linked polar polymer particles or inorganic particles and the first non-polar polymer can be further aided by the addition of an inert component and/or other blowing agents, as noted above. In embodiments where the additional component is a polar polymer, it is understood that the polar polymer can be modified by introducing a crosslinking agent that is mixed with a multicomponent product in the extruder, where filtration of the crosslinked polar polymer occurs in the same extruder. (i.e., a single-step process). Alternatively, the polar polymer can be modified in an extruder that is separate from the extruder in which the filtering occurs (i.e., a two-step process).

[0049] In one or more embodiments, filtration occurs at a temperature that is 1) higher than the melting temperature (Tm) of the non-polar polymer with the highest Tm in the multilayer polymer product and 2) lower than the Tm of the polar polymer with the lowest Tm in the multilayer polymer product.

[0050] In other embodiments, when an amorphous polar polymer is present, filtration occurs at a temperature that is 1) greater than the melting temperature (Tm) of the non-polar polymer with the highest Tm in the multilayer polymer product and 2) greater than 50°C than the glass transition temperature (Tg) of the polar polymer with the lowest Tg.

[0051] Before being melted, such as by an extruder, multicomponent polymer products may optionally be subjected to a size reduction processing step. This size reduction step can occur by shredding, grinding, grinding, chopping, granulation, agglutination or combinations thereof. Such size reduction may depend, for example, on the type and/or size of the multicomponent polymer product provided to the recycling system. In particular embodiments, it is envisaged in the case of a laminate with an inorganic material, the size reduction step may reduce the layer of inorganic material to a particular size, depending on the size of the mesh screen that will filter the inorganic material from the molten polymer.

[0052] Furthermore, also before being cast, it is anticipated that the multilayer product being cast will be analyzed by DSC or DMA to detect the melting temperature of the glass transition temperature of polar and non-polar polymers before being cast. Such analysis can be used to determine the appropriate melting conditions for a given multilayer product.

[0053] In one or more embodiments, extrusion can result in a recycled polymer composition that can subsequently be used to form an article. For example, recycled polymer compositions can be used in the manufacture of articles including rigid and flexible packaging for food products, household chemicals, chemicals, agrochemicals, fuel tanks, water and gas pipes, shrink films, stretch film, geomembranes, recycled articles and the like. In one or more embodiments, the article may be formed by a process selected from extrusion molding, injection molding, thermoforming, cast film extrusion, blown film extrusion, foaming, extrusion blow molding, ISBM ( Injection, Stretch and Blow Molding), rotomolding, pultrusion, additive manufacturing, lamination and the like, to produce manufactured articles. Specifically, in one or more embodiments, the article is an injection molded article, a thermoformed article, a film, a foam, a blow molded article, a 3D printed article, a compressed article, a coextruded article, a laminated article , an injection and blow molded article, a rotomolded article, an extruded article or a pultruded article.

[0054] It is also anticipated that the additional component, filtered from the molten polymer, such as inorganic materials or cross-linked polar polymer particles, can also be used in the manufacture of articles that are applicable.

EXAMPLES Composition and melting point identification

[0055] A multilayer film defined as MULTI was processed in accordance with the present description. In order to evaluate the composition, product and melting points, DSC analysis according to ASTM D3418 were performed using DSC TA-100 under argon atmosphere (flow rate 50 mL/min). Samples were heated to 270°C and held for 5 min. After that, the samples were cooled to -20°C at 20°C/min and reheated at 10°C/min to 280°C.

[0056] Figure 1 shows the second DSC heat curves for the sample, and the results of the suggested polymer present in the product based on melting temperature (Tm2) are detailed in Table 1 below. Table 1: DSC analysis result for the two multilayer polymer products

[0057] The inventive processes were carried out in two different processing approaches: (i) in single extrusion, where melting (and optionally cross-linking) and filtering occur in a single extrusion step; and (ii) in double extrusion, where, in the first extrusion, melting (and optionally cross-linking) occurs while filtering occurs in a second extrusion step. It is apparent to one skilled in the art that, between the two extrusion steps, the material formed after the first extrusion step can be pelletized to be fed into the second extrusion step.

[0058] In examples where a cross-linking reaction occurs, cross-linking agents (CA) were used as a standard mixture prepared in a ZSK-18 twin-screw extruder. The master mix was prepared with a 20 wt% concentration of cross-linking agent (CA) using a linear low-density polyethylene (LLDPE) with a melt flow index of 1 g/10 min measured according to ASTM D1238 (190° C/2.16 kg) as a carrier in powder form to absorb liquid CA. The master mix was extruded at a temperature profile of 100/160/180/180/170/170/170/170/180/190°C. The use of CA standard mixing is useful to make the feeding process simple and applicable to any already installed extrusion process without modifications to the plant. The selected CAs can be polyfunctional molecules, such as with more than 3 functional groups.

[0059] The filtering process was carried out in a Haake, Rheomix extruder, from Thermo Scientific. The single screw extrusion process was conducted at 50 rpm with a filter on a fixed plate with a 200/500/320/120/60 mesh screen assembly to withstand the screen pressures without screen rupture. DSC curves from the second heating were used to evaluate the composition samples after extrusion. The analysis was based on the enthalpy and melting temperature changes of the multilayer product. Furthermore, SEM evaluation was done to confirm the filtration effectiveness. From DSC and SEM, it is possible to verify the filtration efficiency for each multilayer sample. This efficiency is generally related to the increase in PE enthalpy, reduction in dispersed polar phase enthalpy and also to the lower amount of dispersed particles when comparing SEM images. Samples can be examined using SEM after hot pressing the samples according to ASTM D-4703 and cryo-ultramicrotomy polishing of the inside of the plate. Samples can be dried and subjected to gold metallization. Images were obtained by Tabletop SEM (Model TM-1000, from Hitachi).

EXAMPLE 1 - Thermal Filtration (without crosslinking)

[0060] A thermal approach was taken to define the temperature for working with the MULTI sample in subsequent examples. In this example, the melting processes proceed without the use of a cross-linking agent to improve the viscosity of the dispersed polar particles. Table 2: Process conditions of Inventive Example 1 as described in the present description

[0061] For both examples 1a and 1b, melting and filtering occurred in different extrusion steps, but the temperature in the first extrusion step was higher in Example 1b. Filtration is conducted in the second step, where samples would be filtered at temperatures below the lowest melting temperature of polar polymers (<215°C) and higher than the highest melting temperature of non-polar polymers (>162° W) .

[0062] In a DSC analysis, one skilled in the art, upon reading this description, may conclude that a decrease in the enthalpy value of the polar polymer followed by an increase in the enthalpy value of the PE is an indication that some type of polymer is being retained on the filter when coupled with a microscopy analysis.

[0063] The comparison, with the samples from the first extrusion (1a DEI and 1b DEI) and the second extrusion (1a DEII and 1b DEII), follows the criteria of increasing PE enthalpy and decreasing polar polymer enthalpy.

[0064] The enthalpy and melting temperatures for each of the materials detected in the DSC curves for Example 1a (Figure 2A) and Example 1b (Figure 2B) are detailed in the tables below. The increase or decrease (expressed as ΔΔH in %) of enthalpy values compared to the filtered reference of each material were also calculated according to the equation below: ΔΔHpolymer (%) = ((ΔHpolymer after filtration-ΔHpolymer before filtration) /ΔΔHpolymer before filtration)* 100

[0065] In these examples, there is a small change in the melting temperature of PA in Example 1a (as can be seen in DSC shown in Figure 2A), and in the filtering step, which could be the explanation for a higher value in enthalpy of PA in this sample. Table 3: Enthalpy values of Inventive Example 1

[0066] SEM images were used to verify the morphology of the samples before filtration and after filtration for each sample (FIG. 3A and 3B). The squares drawn in the SEM images represent a #500 mesh. The 2 different microscopies show reduction in particle number and particle size in the DEII step for both temperatures. It is also possible to observe that, for example 1b, there are larger particles and a complete reduction in the enthalpy of both polar polymers, and no increase in the enthalpy of the PE phase was observed, which indicates that, at 280°C in the melting stage, the amorphous phase was obtained and thermal filtration was not efficient. The combination of enthalpy and SEM images shows that for thermal filtration there is a temperature limit to operating the system at higher temperatures, albeit bringing about a stronger process of coalescence of the polar polymers (as seen by the larger particle size of example 1b DEI in FIG. 3B), the higher temperature can culminate in a degradation process of the dispersed phase, so that a lower temperature in the melting step appears to be more effective for the inventive filtering process.

EXAMPLE 2 - Evaluation of different crosslinking agents (CA)

[0067] To evaluate the increase in viscosity of polar polymers by crosslinking, aiding the coalescence process in the melting step, two different crosslinking agents - citric acid and tetra-n-butyl titanate (TnBT - commercially available as Tyzor® TnBT ) - were chosen to verify their activity throughout the PA6 and PET phase in the MULTI multilayer polymer product, in order to verify their interactions with both polar polymers. A reference filtration, without cross-linking, was also performed in order to verify the unique effect of the filtration process and compare the effects of cross-linking on the process. A DSC analysis was conducted for the unfiltered material (reference), the filtered reference, and the filtered cross-linked materials (Multi Citric Ac. and Multi Tyzor). Figure 4 displays DSC curves for each material. Table 4 shows the process conditions and CA concentrations used. Table 4: Process conditions of the inventive examples as described Standard mixTB: LLDPE + Tetra-n-butyl-titanate (TnBT) Standard mixCA: LLDPE + Citric Acid (CA)

[0068] The enthalpy of each polymer phase was calculated as follows:

[0069] ΔΔHpolymer(%)=((ΔHpolymer after filtration-filtered reference of ΔHpolymer)/filtered reference of ΔΔHpolymer)*100 Table 5: Enthalpy measurements for samples from Example 2 Table 6: Melting points (°C) for the polymers in each sample from Example 2

[0070] Comparing the cross-linked and non-cross-linked material, no significant change can be observed in Tm.

[0071] In a DSC analysis, one skilled in the art may conclude that a decrease in the enthalpy value of the polar polymer followed by an increase in the enthalpy value of the PE is an indication that some type of polymer is being retained in the filter, when no significant change in melting point is detected (thus indicating that there is no destruction of the crystallinity of the polymer).

[0072] For citric acid, there is a slight reduction in the melting point of PA6, but no change in PET can be detected. As the PA6 enthalpy decreases and the PE enthalpy increases, there is an indication that some PA6 was retained during the filtration process (but a concurrent process of destruction of crystallinity may also be present due to the lowering of the melting point). . No change in PET enthalpy nor melting temperature was detected, indicating that citric acid does not react with PET.

[0073] For TnBT, an increase in the enthalpy of PE and a decrease in the enthalpies of PET and PA6 can be detected, without significant changes in the melting point, indicating that the PA6 and PET were retained in the filtration process. In this particular case, it can be seen that the same crosslinking agent (TnBT) can be used to crosslink different polar polymers, indicating that some CAs can be used alone in the filtration process of multilayer products comprising more than one polar polymer.

[0074] As TnBT is the crosslinking agent that acts most favorably in the filtration process, it is also used in the following Examples 3 and 4 as the crosslinking agent fed as a master mix composition in order to simplify its application in the filtration process. extrusion.

EXAMPLE 3 - Assessment of crosslinking agent concentration

[0075] Example 3 is conducted in double extrusion with a crosslinking step, with a varying concentration of crosslinking agent (3% by weight and 5% by weight) in the MULTI sample. The cross-linking agent acts on the polar polymer particles, increasing coalescence between the polymer particles and increasing their viscosity under process conditions similar to those in Example 1a. DSC analysis was conducted for samples after cross-linking but before filtration (3aDERI and 3bDERI) and after filtration (3a DERII and 3b DERII). The comparison between the DSC curves before and after filtering is illustrated in Figure 5A and 5B. Table 7: Process conditions of Inventive Example 3 Standard mixtureTB: LLDPE + Tetra-n-butyl-titanate (TnBT) Table 10: Enthalpy for the polymers in each sample from Example 3

[0076] As a cross-linking step occurs, the reduction in complete enthalpy for PET is the result of the chemical reaction, likely transforming the PET into an amorphous phase (i.e., not detectable by DSC). This reaction is expected to generate a phase with a higher molecular mass, which is easier to coalesce and be removed by filtration.

[0077] Figures 6A and 6B show the SEM images for both samples before filtration and after filtration. The higher cross-linking agent content appears to accelerate the reaction on the polar polymer phase, leading to a likely competition between coalescence and cross-linking, where the higher CA concentration causes a faster reaction leading to a difficulty in the coalescence process before cross-linking. , resulting in smaller particles (as can be seen by comparing example 3a DERI and example 3b DERI in SEM images). However, a reduction in the number of particles and the size of the dispersed phase of the resulting polar polymer is observed. The amount of 3 wt% CA appears to be more suitable for modification due to the increase in PE enthalpy and reduction of polymer particles in the SEM images.

EXAMPLE 4

[0078] In example 4, crosslinking with 3 wt% CA at two different temperatures in simple extrusion was tested Table 11: Process conditions for Example 4 Table 12: Enthalpy values for Example 4

[0079] Enthalpy values for samples before the filtration process and after filtration are detailed in Table 12.

[0080] Crosslinking and filtration appear to be more efficient in relation to the PET phase, as there is almost no change in the enthalpy of PE, it seems evident that an amorphous phase was formed instead of retaining the particles in filtration. As there is a competition between particle coalescence and the cross-linking process, the coalescence process may not be present efficiently, and the reaction occurred before the formation of the ideal particle size. When the process occurs in a single step, a different extrusion configuration, such as feeding the cross-linking agent into the middle of the extruder, can lead to correct reaction time, therefore, leading to efficient filtration.

[0081] Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily recognize that many modifications are possible in the exemplary embodiments without departing materially from this invention. Accordingly, all such modifications are intended to be included within the scope of this description as defined in the following claims. In the claims, means plus function clauses are intended to cover structures described herein as performing the described function and not only structural equivalents, but also structural equivalents. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to hold wooden pieces together while a screw employs a helical surface, in the environment of fastening wooden pieces, a nail and a screw may be equivalent structures. It is Plaintiff's express intention not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations on any of the claims contained herein, except those where the claim expressly uses the words “means for” in conjunction with an associated function.

Claims (17)

1. Method for recycling polymers of a multicomponent polymer product, characterized in that it comprises: subjecting a multicomponent polymer product comprising at least one non-polar polymer and at least one polar polymer to conditions for melting the at least one non-polar polymer and the at least one polar polymer, and allowing coalescence of the at least one polar polymer to form coalesced polar polymer particles dispersed in a continuous phase, wherein the continuous phase is the at least one non-polar polymer; and at least partially filtering the dispersed polar polymer from the continuous phase, wherein the filtration step occurs at a temperature higher than the melting temperature (Tm) of the non-polar polymer and at a temperature lower than the Tm of the polar polymer. 2. Method according to claim 1, characterized by the fact that the subjection further comprises subjecting to conditions to selectively cross-link the polar polymer before filtration. 3. Method according to any one of claims 1 to 4, characterized by the fact that the multicomponent polymer product is a multilayer polymer product. 4. Method according to claim 1, characterized by the fact that the polar polymer particles comprise a semi-crystalline polymer. 5. Method according to claim 4, characterized by the fact that the melting conditions in the subject comprise subjecting the multicomponent polymer product to a temperature higher than the highest melting temperature (Tm) detectable in a DSC curve of the product multicomponent polymer. 6. Method according to claim 1, characterized by the fact that the polar polymer particles comprise an amorphous polymer. 7. Method according to claim 6, characterized by the fact that the melting conditions in the subject comprise subjecting the multicomponent polymer product to a temperature at least 50 ° C higher than the highest detectable glass transition temperature (Tg). on a DMA curve of the multicomponent polymer product. 8. Method according to any one of the preceding claims, characterized by the fact that the polar polymer particles have an average particle size that is at least 15 μm. 9. Method according to any one of the preceding claims, characterized by the fact that the non-polar polymer is a polyolefin. 10. Method according to any one of the preceding claims, characterized in that the polar polymer comprises at least one functional group selected from the group consisting of hydroxyl, carboxylic acid, carboxylate, ester, ether, acetate, amide, amine , epoxy, imide, imine, sulfone, phosphone and their derivatives. 11. Method according to any one of the preceding claims, characterized in that the polar polymer is selectively cross-linked by a cross-linking agent selected from the group consisting of maleic anhydride, maleic acid, itaconic acid, itaconic anhydride, succinic acid , succinic anhydride, succinic aldehyde, adipic acid, adipic anhydride, phthalic anhydride, phthalic acid, glutaconic acid, glutaconic anhydride, glutaraldehyde, citric acid, sodium tetraborate, organic titanates such as tetrabutyl titanate, organic zirconates such as zirconium(IV) bis(diethyl citrate)dipropoxide, methoxy polyethylene glycol acrylates, ethoxy polyethylene glycol acrylates, ethylene glycol diacrylate, ethylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol diacrylate , neopentyl glycol dimethacrylate, trimethylol ethane triacrylate, trimethylol ethane trimethacrylate, trimethylol propane triacrylate, trimethylol propane trimethacrylate and tetramethylol methane tetraacrylate, their derivatives and mixtures thereof. 12. Method according to any one of the previous claims, characterized by the fact that clamping and filtration occur in an extruder. 13. Method according to claim 14, characterized in that the clamping and filtration occur in two different extrusion steps. 14. Method according to claim 12 or 13, characterized by the fact that it further comprises injecting an inert component into the extruder selected from the group consisting of CO2, N2, water, organic solvents and combinations thereof, in a gaseous state, liquefied or supercritical, wherein the inert component is capable of swelling the at least one molten polar polymer or continuous phase, and wherein the inert component is injected in an amount in the range of 0.5 to 20% by weight of the product. multicomponent polymer. 15. Method according to any one of claims 12 to 14, characterized in that it further comprises: injecting a blowing agent into the extruder, wherein the blowing agent produces an inert component capable of swelling the at least one molten polar polymer or the continuous phase by decomposition. 16. Method according to claim 14 or 15, characterized by the fact that it further comprises degassing the at least one molten non-polar polymer or the continuous phase after filtration. 17. Recycled polymer composition, characterized in that it comprises the filtered polar polymer, the filtered continuous phase or the filtered non-polar polymer produced by the method as defined in any of the preceding claims.