Method of preparing a recycled resin composition, recycled resin composition and article
Patent Information
- Application Number
- BR112022019483
- Authority / Receiving Office
- BR · BR
- Patent Type
- Patents
- Current Assignee / Owner
- Publication Date
- 2026-08-11
Smart Images
Figure 00000031_0000
Abstract
Description
1 / 27 Descriptive Report of Invention Patent METHOD FOR PREPARING A RECYCLED RESIN COMPOSITION, RECYCLED RESIN COMPOSITION AND ARTICLE Field of Invention
[0001] The present invention relates to a resin composition having recycled polyolefin. It also relates to films and packaging comprising the resin composition. Background of the Invention
[0002] Synthetic plastics are used in a wide variety of applications, for example, in packaging and consumer products. Synthetic plastics are in high demand in these applications due to their relatively low production costs and good balance of material properties.
[0003] To meet the growing demand, millions of tons of synthetic plastics are produced worldwide. Most synthetic plastics are produced from increasingly scarce fossil fuels, such as oil and natural gas. The production of plastic from fossil fuels contributes to increased levels of greenhouse gases.
[0004] The universal use of synthetic plastics has consequently resulted in millions of tons of plastic waste being generated each year. Most of the plastics used end up in landfills, some as litter, and still others end up in bodies of water.
[0005] There is environmental pressure on the industry to recycle waste polymers, particularly those used in packaging applications. Plastic recycling has emerged as a solution to mitigate the problems associated with the widespread use of plastics. Simple or mixed streams of waste plastic are sorted, washed, and reprocessed into pellets that are suitable for reuse in plastic processing. Petition 870220088506, dated 09 / 27 / 2022, page 7 / 44 2 / 27
[0006] Polyethylenes (PE), in the form of high-density polyethylene (HDPE) suitable for molding, and low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE) suitable for film, currently make up more than half of the recycled polymer market. These form the largest polymeric portion of post-consumer waste streams, with significant amounts of polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET), and small amounts of other polymers such as polyamides, polycarbonates, and barrier polymers. Also, within post-consumer recycled plastic or PCR, as it is more commonly known, there is a mixture of various types of polyethylenes including HDPE, LDPE, LLDPE, etc., and a mixture of polymers of different molecular weights, i.e., mixtures of low and high molecular weights (MW).
[0007] Despite undergoing sorting processes, post-consumer waste-recovered PE inevitably contains significant amounts of other polymeric contaminants. For example, PE contamination in recycled PP and vice versa. Commercial post-consumer waste material recycles have been found to generally contain mixtures of PP and PE, with the minor component reaching up to < 50% by weight. These recycled PP / PE blends typically have deteriorated mechanical and optical properties, poor odor and taste performance, and generally low compatibility between the main polymeric phases, resulting in limited impact resistance and heat deflection resistance.
[0008] The mechanical properties of recycled PE blends can be significantly compromised, since the degradation suffered by PE during processing and subsequent service life worsens the polymeric characteristics of the polymers and, therefore, recycling operations give rise to secondary materials with poor properties. This applies to all recycled polymers, both homogeneous and heterogeneous, but especially to the latter. Petition 870220088506, dated 09 / 27 / 2022, page 8 / 44 3 / 27 In cases containing a significant amount of polymer contamination, the problem is more pronounced.
[0009] It is observed that processing post-consumer recycled (PCR) plastic by mechanical or hybrid recycling subjects the polymer to thermal stress, leaving the recycled plastic with inferior properties. Films prepared from this recycled plastic undergo gel formation during processing. These gels result in inferior properties, as the film suffers perforation and leakage. Another disadvantage of using recycled resin is that physical characteristics of the composite may be lacking compared to virgin material. For example, characteristics such as modulus of rupture, modulus of elasticity, peak load, and other mechanical properties can be adversely impacted by the use of recycled material in many common applications.
[0010] Also, reprocessed pellets often remain highly contaminated with unwanted residual impurities, for example, spoiled food residue and residual perfume components. In addition, most post-consumer recycled plastic pellets have a dark color due to the mixture of dyes and pigments commonly used to color plastic articles.
[0011] Consequently, there is a need to be able to use recycled material while still maintaining physical characteristics equal to or similar to virgin materials. Thus, a need for high-quality "virgin-type" recycled resin is desired.
[0012] Since thermal degradation and shear stresses applied during recycling reduce the properties of polymers, the addition of suitable reinforcing material as an approach to improve properties has been attempted in the past.
[0013] There have been several attempts in the past to improve the mechanical and physical properties of post-consumer recycled plastics. Petition 870220088506, dated 09 / 27 / 2022, page 9 / 44 4 / 27
[0014] One of these attempts occurred in document US 3862265A (Steinkamp et al., 1975) which discloses polyolefin with improved rheology, modified molecular weight and flow properties, with the document revealing grafted polymers with relatively narrow molecular weight distributions.
[0015] Document EP0964022 A1 (Bridgestone Corporation, 1999) discloses a polymer blend of a maleated polypropylene and an amine-terminated polybutadiene in which amine functionalization links the polybutadiene and the maleated propylene.
[0016] Document WO2007 / 078697 A1 (Dow Global Technologies Inc) discloses a polymer with a vinyl group at one end of the polymer where the end can be further functionalized by grafting.
[0017] The state-of-the-art document discusses improving the properties of unused virgin polyolefins. Thus, the problem of recovering the mechanical properties of already processed, used and recycled polymeric material, in particular used polyolefins or mixed polyolefins, continues to be addressed.
[0018] Thus, it is an objective of the present invention to provide a recycled resin composition with a recycled polyolefin having improved functional properties, similar to the properties of a virgin polyolefin.
[0019] It is yet another objective of the present invention to provide an article having higher levels of inclusion of the recycled resin composition according to the present invention without compromising processability and functional parameters.
[0020] Therefore, it is an objective of the present invention to obtain a recycled resin composition that exhibits high stiffness, as well as high resistance to impact and heat deflection temperature, while at the same time exhibiting good flowability and processability.
[0021] An additional objective of the present invention is to improve both the mechanical properties and the processability of the recycled resin composition, in order to make them suitable for use in different applications. Petition 870220088506, dated 09 / 27 / 2022, page 10 / 44 5 / 27 Summary of the Invention
[0022] The present inventors have discovered that the mechanical properties, and in particular the tensile properties of a recycled polyolefin, are notably improved in the recycled resin composition of the present invention when a terminal end of a recycled polyolefin unit is linked to a functional polymer by a terminal link and the recycled resin composition has a weighted average molecular weight of 10,000 kg / mol to 50,000 kg / mol.
[0023] According to a first aspect of the present invention, a recycled resin composition is disclosed comprising: i) recycled polyolefin; and, ii) from 10% by weight to 25% by weight of functional polymer selected from anhydride-grafted polyolefin, acid-grafted polyolefin or combinations thereof; wherein the recycled polyolefin unit has unsaturation at at least one terminal end and the terminal end of the recycled polyolefin is linked to the functional polymer and wherein the recycled resin composition has a weighted average molecular weight of 10,000 kg / mol to 50,000 kg / mol.
[0024] According to a second aspect, the present invention relates to a method of preparing a recycled resin composition according to the first aspect, comprising the steps of: i) blending recycled polyolefin, preferably having a weighted average molecular weight in the range of 5,000 kg / mol to 40,000 kg / mol, and 10% to 25% by weight of functional polymer selected from acid-grafted polyolefin, anhydride-grafted polyolefin, or combinations thereof, to form a blend; ii) heat the mixture to a temperature in the range of 145 °C to 200 °C; Petition 870220088506, dated 09 / 27 / 2022, p. 11 / 44 6 / 27 iii) apply shear pressure to the heated mixture to connect the terminal end of a recycled polyolefin unit and the functional polymer to form a recycled resin composition; and, iv) obtain the recycled resin composition, wherein the recycled polyolefin unit has an unsaturation at at least one terminal end and the terminal end of the recycled polyolefin unit is connected to the functional polymer and wherein the recycled resin composition has a weighted average molecular weight in the range of 10,000 kg / mol to 50,000 kg / mol.
[0025] According to a third aspect, the present invention relates to an article comprising a recycled resin composition according to the first aspect or prepared according to the second aspect. Preferably, the article is a film or a molded article.
[0026] As used herein, the term “recycled” polyolefin includes post-consumer recycled polyolefin (PCR), post-industrial recycled polyolefin (PIR), or a mixture thereof. These are preferably mixed polyolefins including polyethylene or polypropylene. In particular, the polyethylene fraction may comprise one or more materials selected from high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), or mixtures thereof.
[0027] As used herein, the term “post-consumer recycled” (PCR) refers to a material (e.g., a polymer or polymers) that has reached the intended end user or consumer, is no longer being used for its intended purpose, and has been collected or recovered after being discarded by the end user or consumer. Thus, for example, it is understood that the term refers to a material that would otherwise have been discarded as waste, but which has been collected and recovered (reclaimed) as an input material, rather than a new virgin material, for a recycling or manufacturing process. The term includes all collected or recovered materials that have been further treated or processed to facilitate the reuse of the material. Petition 870220088506, dated 09 / 27 / 2022, page 12 / 44 7 / 27 Thus, for example, the term includes material that has been reprocessed from collected or recovered material through a manufacturing process and transformed into a product or component for incorporation into a product. The term "recycled" includes polyolefin that has been used and subsequently introduced into an established recycling stream.
[0028] As used herein, the term “post-industrial recycled” (PIR) refers to a material (e.g., a polymer or polymers) that never reached the end user and that has been collected or recovered from a waste stream produced in a manufacturing process. The term “post-industrial recycled” does not include materials that are generated in a manufacturing process and that are then reused as a substitute for a raw material in the same manufacturing process, for example, milled polymer that is collected from the waste stream of a manufacturing process (e.g., a thermoforming process), crushed to reduce its size, and then reused as a substitute for virgin polymer in the same manufacturing process (e.g., the same thermoforming process). The term includes collected or recovered materials that have been further treated or processed to facilitate the reuse of the material in another manufacturing process.
[0029] The term “polymer”, as used in this application, denotes a material having a weighted average molecular weight (Mw) of at least 5,000.
[0030] The term “virgin polymer”, as used herein, denotes a polymer that has not been used by an end consumer / user and has therefore been recycled.
[0031] The term “acid-grafted polyolefin”, as used herein, denotes a polyolefin grafted with an acid component or derivatives thereof.
[0032] The term “anhydride-grafted polyolefin”, as used herein, denotes both a polyolefin grafted with an anhydride component and derivatives thereof. Brief Description of the Figures Petition 870220088506, dated 09 / 27 / 2022, page 13 / 44 8 / 27
[0033] Figure 1 refers to a 13C NMR plot of recycled polyolefin showing the presence of unsaturated functional moieties with peaks at positions 4 and 3. The peaks at 110 ppm and 135 ppm confirm the presence of unsaturation at the terminal position of the recycled polyolefin chains. All other peaks with greater lengths signify the ethylene chain of polyethylene and its chain linkage. Detailed Description of the Invention
[0034] According to the first aspect of the present invention, a recycled resin composition is disclosed that includes recycled polyolefin and a functional polymer. Recycled polyolefin
[0035] According to a first aspect of the present invention, the disclosed recycled resin composition includes a recycled polyolefin.
[0036] Recycled polyolefin may be any suitable polyolefin or combination of polyolefins. Typically, recycled polyolefin is selected from the group consisting of polypropylene, polyethylene and mixtures thereof. Preferably, the recycled polyolefin is polyethylene, preferably the recycled polyethylene includes plain polyethylene or mixed polyethylene selected from LDPE, HDPE, LLDPE or mixtures thereof.
[0037] Preferably, the recycled polyethylene content in the recycled polyolefin is at least 50% by weight, even more preferably at least 60% by weight, even more preferably at least 70% by weight, even more preferably at least 75% by weight and, most preferably, at least 80% by weight of the recycled polyolefin.
[0038] Preferably, the recycled polyolefin may be post-consumer recycled polyolefin, for example, post-consumer recycled polyethylene (PCR-PE) or post-industrial recycled polyolefin, for example, post-consumer recycled polyethylene. Petition 870220088506, dated 09 / 27 / 2022, p. 14 / 44 9 / 27 industrial (PIR-PE). Preferably, the recycled polyolefin is a mechanically recycled material.
[0039] Preferably, the weighted average molecular weight of the recycled polyolefin is from 5,000 kg / mol to 40,000 kg / mol. Preferably, the weighted average molecular weight of the recycled polyolefin is at least 8,000 kg / mol, even more preferably at least 9,000 kg / mol, but preferably not more than 30,000 kg / mol, even more preferably not more than 25,000 kg / mol and even more preferably not more than 10,000 kg / mol. Preferably, the recycled polyolefin has a molecular weight distribution (Mw / Mn) in the range of 5 to 8, even more preferably from 5 to 7.
[0040] Preferably, the recycled polyolefin is a recycled mixed polyolefin comprising at least 80% by weight of LLDPE, LDPE and HDPE.
[0041] In a preferred embodiment, the recycled polyolefin is predominantly derived from post-consumer recycled polymer (PCR). Preferably, at least 50% by weight, still preferably at least 60% by weight, still preferably at least 70% by weight, still preferably at least 75% by weight, and most preferably at least 80% by weight of the recycled polyolefin content is from post-consumer recycled polymer (PCR).
[0042] This recycled polyolefin is commercially available, for example, from Corpela (Italian consortium for the collection, recovery, recycling of plastic packaging waste), Resource Plastics Corp. (Brampton, ON), Kruschitz GmbH, Plastics and Recycling (AT), Vogt Plastik GmbH (DE), etc. A preferred recycled polyolefin is LDPE recycled from Ecoplast.
[0043] In recycled polyolefin, preferably the polypropylene content is in the range of 30 parts to 70 parts by weight of recycled polyolefin, and 70 parts to 30 parts by weight of recycled polyolefin is the polyethylene content. More preferably, 40 parts to 60 parts of the polypropylene content, and 60 parts to 40 parts of the polyethylene content. More Petition 870220088506, dated 09 / 27 / 2022, page 15 / 44 10 / 27 Preferably, recycled polyolefin (recycled) is rich in LDPE and is commercially available from Ecoplast under the trade name NAV 102.
[0044] Preferably, the recycled polyolefin is a recycled polyethylene having a melt flow index at 190 °C and 2.16 kg of 0.2 to 0.8 g / 10 minutes. The melt flow index is measured using the ISO 1133 / 99 standard method.
[0045] Preferably, recycled polyethylene has an apparent density of 450 g / L to 500 g / L when measured using the ISO 60 / 77 standard method.
[0046] The recycled polyolefin unit has unsaturation at at least one terminal end. It is believed that the conditions during the recycling process lead to the formation of unsaturation at the terminal end of the polyolefin unit due to the dismutation termination mechanism as described below. hrh .R। । ir y Polymer chain -Ç-CC^C· Dismutation Η Η Η H ----------R = H for PE 7 R = CHa for PP RHRH '-•C— C~C— C— Polymer chain H H H H HR HRIII Γ polymeric bond —C~C—C=C+Η Η H RHRH III H—C—C~C—C_Polymer chain III H H H H H (I)
[0047] The recycled polyolefin unit has an unsaturation present at at least one terminal end of the polyolefin. Preferably, at least 60% of the recycled polyolefin unit has an unsaturation present at at least one terminal end. Even more preferably, at least 70%, even more preferably at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, even more preferably at least 97%, and most preferably 100% of the recycled polyolefin unit has an unsaturation present at at least one terminal end.
[0048] More preferably, the recycled polyolefin unit has unsaturation present at both terminal ends of the polyolefin unit. It is further preferred that at least 60% of the recycled polyolefin unit has unsaturation present at both terminal ends. Petition 870220088506, dated 09 / 27 / 2022, page 16 / 44 11 / 27 preferably, at least 70%, still preferably at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, still preferably at least 97% and, most preferably 100% of the recycled polyolefin unit has an unsaturation present at both terminal ends.
[0049] Preferably, less than 10% by weight of the recycled polyolefin has a functional group present in the chain of the polyolefin backbone, even more preferably less than 5% by weight of the recycled polyolefin has a functional group present in the chain of the polyolefin backbone, even more preferably less than 3% by weight, still preferably less than 1% by weight, and most preferably the recycled polyolefin is free of functional groups in the chain of the polyolefin backbone. Preferably, the reference to the functional group present in the chain of the polyolefin backbone refers to the functional group grafted or crosslinked into the polyolefin backbone. A functional group should be included in the context of a group other than an alkyl group that is capable of associating with another functional group of another molecule or polymer to form a linkage.Examples of functional groups include amides, amines, carboxyl groups, carbonyl groups, carboxylic acid anhydrides, and hydroxyl groups.
[0050] Preferably, less than 10% by weight of the recycled polyolefin has an unsaturation at a position other than the terminal end of the polyolefin main structure, even more preferably less than 5% by weight of the recycled polyolefin has an unsaturation present at a position other than the terminal end in the polyolefin main structure chain, even more preferably less than 3%, even more preferably less than 1%, and most preferably, the recycled polyolefin is free of any unsaturation at a position other than the terminal end of the recycled polyolefin main structure chain.
[0051] In the recycled resin composition according to the present invention, the recycled polyolefin comprises from 5% by weight to 90% by weight of Petition 870220088506, dated 09 / 27 / 2022, page 17 / 44 12 / 27 composition. Preferably, the amount of recycled polyolefin is at least 10% by weight, even more preferably at least 20% by weight, even more preferably at least 35% by weight, most preferably 40% by weight, with the highest preference being 50% by weight of the recycled resin composition, however preferably the amount of recycled polyolefin is not greater than 85% by weight, even more preferably not greater than 80% by weight, even more preferably not greater than 75% by weight and, most preferably, not greater than 70% by weight of the recycled resin composition.
[0052] The recycled resin composition may further comprise virgin polyolefin. When present, the virgin polyolefin is present in an amount of 1% by weight to 50% by weight of the composition, preferably 5% by weight to 30% by weight of the composition, even more preferably 5% by weight to 10% by weight of the composition. Functional polymer
[0053] The disclosed recycled resin composition includes a functional polymer selected from anhydride-grafted polyolefin, acid-grafted polyolefin, or combinations thereof.
[0054] Preferably, the functional polymer is selected from the group consisting of polyolefin grafted with maleic anhydride, polyolefin grafted with acrylic acid, or combinations thereof. This can be selected from polypropylene grafted with maleic anhydride, propylene grafted with acrylic acid, or combinations thereof. Even more preferably, a polyethylene grafted with acrylic acid, polyethylene grafted with maleic anhydride, or combinations thereof.
[0055] More preferably, the functional polymer is an acrylic acid-grafted LDPE, acrylic acid-grafted LLDPE, acrylic acid-grafted HDPE, or combinations thereof.
[0056] Preferably, the functional polymer is selected from the group consisting of high-density polyethylene grafted with maleic anhydride, Petition 870220088506, dated 09 / 27 / 2022, page 18 / 44 13 / 27 low-density polyethylene grafted with maleic anhydride, linear low-density polyethylene grafted with maleic anhydride, polyethylene wax grafted with maleic anhydride, polypropylene grafted with maleic anhydride, copolymers of propylene grafted with maleic anhydride with other alpha-olefins, for example, butene, hexene, and octene, high-density polyethylene grafted with acrylic acid, low-density polyethylene grafted with acrylic acid, polypropylene grafted with acrylic acid, copolymers of propylene grafted with acrylic acid with other alpha-olefins, for example, butane, hexene, and octane, copolyethylene vinyl acetate, and combinations thereof. Examples of these commercially available functional polymers include, but are not limited to: Polybond (SI Group USA LLC.), Orevac and Lotader (Arkema), Licomont (Clariant), Epolene (Eastman), Integrate (Equistar), Exxelor (ExxonMobil), AC Waxes and Optipak (Honeywell), Fusabond (EIDuPont de Nemours), and Bondyram (Polyram). The functional polymer can be produced by reactive extrusion processes in which the non-functionalized polymer resin is reacted with maleic anhydride or acrylic acid and an initiator to form the functional polymer during extrusion in a twin-screw extruder at elevated temperature.
[0057] Other suitable functional polymers that may be included in the recycled resin composition of the present invention include, but are not limited to, succinyl anhydride-substituted polyolefins, vinyl acetate-grafted polyolefins, and the like, and combinations thereof.
[0058] In addition to traditional reactive extrusion products, the functional polymer can be a non-traditional anhydride-substituted polyolefin prepared by copolymerizing a cyclic anhydride with an olefin. An example of such a non-traditional anhydride-substituted polyethylene is Fusabond WPC576 (EI DuPont de Nemours). The functional polymer can also be prepared by reacting maleic anhydride with a polyolefin wax at elevated temperature. Examples of such functional polymers are products manufactured by Clariant, Eastman, and Honeywell. Petition 870220088506, dated 09 / 27 / 2022, p. 19 / 44 14 / 27
[0059] The functional polymer is most preferably selected from the group consisting of maleic anhydride grafted high-density polyethylene (“maleated”) (Polybond 3009, Polybond 3029, Polybond 3039), maleic anhydride grafted linear low-density polyethylene (Polybond 3109), maleic anhydride grafted polypropylene (Polybond 3000, Polybond 3200), acrylic acid grafted high-density polyethylene (Polybond 1009), acrylic acid grafted polypropylene (Polybond 1001, Polybond 1002), and combinations thereof; all are available from Chemtura Corporation SN SI Group.
[0060] Other non-limiting examples of suitable functional polymers include Polybond® 1001, Polybond® 1002, Polybond® 1009, Polybond® 3000, Polybond® 3002, Polybond® 3009, Polybond® 3150, and Polybond® 3200. The Polybond® series is commercially available from Chemtura, USA, and consists of polypropylenes and / or polyethylenes functionalized with maleic anhydride. Polybond® 3150 has an MFI of 50 g / 10 min, 230 °C, 2.16 kg; and Polybond® 3200 has an MFI of 110 g / 10 min, 190 °C, 2.16 kg.
[0061] The functional polymer is preferably HDPE grafted with acrylic acid (Polybond 1009 from SI Group). The functional polymer has from 3% to 10% by weight, more preferably from 3% to 8% by weight of the functional acid or anhydride group by weight of the functional polymer. The functional polymer preferably has an acrylic acid content of 3% to 10% by weight, still preferably from 3% to 8% by weight, and most preferably from 5.5% to 6.5% by weight of the functional polymer. Preferably, the melt melt index (MFR when measured using the ASTM D-1238 method) is 5 g / 10 min to 10 g / 10 min at 190 °C and 2.16 kg.
[0062] Preferably, the functional polymer has a melting point in the range of 120 °C to 130 °C when measured using the DSC method. The apparent density of the functional polymer is preferably from 0.5 g / cm3 to 0.9 g / cm3 when measured using the ASTM D-1895B method. Petition 870220088506, dated 09 / 27 / 2022, page 20 / 44 15 / 27
[0063] The disclosed recycled resin composition comprises from 10% by weight to 25% by weight of functional polymer. Preferably, the amount of functional polymer is from 10% by weight to 25% by weight of the composition, even more preferably from 10% by weight to 20% by weight of the composition. In the recycled resin composition, preferably the amount of functional polymer is at least 10% by weight, even more preferably at least 12% by weight, even more preferably at least 13% by weight, most preferably 14% by weight, with the highest preference of 15% by weight of the recycled resin composition, but preferably the amount of functional polymer is not greater than 24% by weight, even more preferably not greater than 23% by weight, even more preferably not greater than 21% by weight and, most preferably, not greater than 20% by weight of the recycled resin composition.
[0064] Preferably, the polymeric portion of the functional polymer has a weighted average molecular weight of 10,000 to 30,000 kg / mol. Recycled resin composition
[0065] In the recycled resin composition of the present invention, a unit of recycled polyolefin is linked to the functional polymer. Furthermore, the recycled resin composition has a weighted average molecular weight of 10,000 kg / mol to 50,000 kg / mol.
[0066] Preferably, the recycled resin composition has a weighted average molecular weight of 15,000 kg / mol to 40,000 kg / mol, and most preferably of 15,000 kg / mol to 30,000 kg / mol. The weighted average molecular weight is calculated following rheological characterization that does not use polydisperse glass beads. The molecular weight determination was performed by the ASTM D4440-15 rheological melting method using frequency sweep, and the viscosity data were then plotted on the Carreau-Yasuda equation to obtain the molecular weight. Petition 870220088506, dated 09 / 27 / 2022, page 21 / 44 16 / 27
[0067] In the recycled resin composition, a terminal end of the recycled polyolefin unit is attached to the functional polymer. Preferably, at least 60% of the recycled polyolefin is attached to the functional polymer. Even more preferably, at least 80% by weight of the recycled polyolefin is attached to the functional polymer, with the most preference in the recycled resin composition according to the present invention being 95% by weight to 100% by weight of the recycled polyolefin unit attached to the functional polymer, wherein the terminal end of the recycled polyolefin unit is attached to the functional polymer.
[0068] Preferably, in the disclosed recycled resin composition, the functional polymer links two recycled polyolefin units. That is, one unit of the functional polymer is linked to the terminal end of two recycled polyolefin units.
[0069] Preferably, the functional polymer has a pendant carboxyl group capable of forming a chemical bond with the unsaturation present at a terminal end of the recycled polyolefin via the terminal hydroxyl groups of the functional polymer. Preferably, the chemical bond is a covalent bond. Preferably, the hydroxyl group of the functional polymer is linked to the unsaturation present at a terminal end of the recycled polyolefin, preferably the bond is a chemical bond, still preferably a covalent bond.
[0070] In the recycled resin composition, one unit of the functional polymer links two units of recycled polyolefin. The functional polymer has units of acidic or anhydride functional groups. The functional groups in the functional polymer are of the same type or of different types, preferably of the same type. More preferably, one unit of the acidic or anhydride group of the functional polymer forms a covalent bond with the unsaturation present at the terminal end of one unit of recycled polyolefin, and the other unit of the same functional polymer forms a covalent bond with the unsaturation present at the terminal end of another unit of recycled polyolefin. Petition 870220088506, dated 09 / 27 / 2022, page 22 / 44 17 / 27
[0071] In the recycled resin composition, the weight ratio between the recycled polyolefin and the functional polymer is in the range of 4:1 to 20:1.
[0072] Preferably, the recycled resin composition has an unsaturation linkage at the terminal end of the recycled polyolefin with the functional polymer, wherein the linkage is formed by free radical polymerization. In free radical polymerization, the functional radical attacks the double bond. This additionally allows chain propagation. The functional polymer attacks the terminal double bond and links one end of the recycled polyolefin to the terminal end of the other recycled polyolefin unit. The functional polymer then forms a bridge between two recycled polyolefin units.
[0073] Preferably, in the recycled resin composition according to the present invention, it has from 10% by weight to 25% by weight of functional polymer bonded to the terminal end of a recycled polyolefin providing an increase in the storage modulus from 122% to 135% compared to the recycled polyolefin.
[0074] The molecular weight of the recycled resin composition also increases compared to recycled polyolefin. An increase in molecular weight and a further increase in storage modulus suggests that the increase in molecular weight is directly associated with the formation of the bond between the functional polymer and the unsaturation at the terminal end of the recycled polyolefin unit. Without wanting to get bogged down in theory, it is believed that when the functional polymer is bonded to the terminal end of the recycled polyolefin unit, and preferably when the functional polymer acts as a bridge between the terminal ends of two polyolefin units, preferably by forming a covalent bond, the bond generates an increase in the chain length of the recycled polyolefin.This increase in chain length causes the recycled polyolefin to form a spiral chain to occupy the crystal lattice during solidification, conferring elasticity and consequently resulting in an increase in the storage modulus. Petition 870220088506, dated 09 / 27 / 2022, page 23 / 44 18 / 27
[0075] Preferably, in the disclosed recycled resin composition, 80% by weight to 100% by weight of the recycled polyolefin are linked to the functional polymer, more preferably 85% by weight to 100% by weight, even more preferably 90% by weight to 100% by weight and, most preferably, 95% by weight to 100% by weight of the recycled polyolefin are linked to the functional polymer. Method for preparing recycled resin composition
[0076] According to a second aspect, a method for preparing a recycled resin composition according to the first aspect is disclosed, comprising the steps of: i) mixing recycled polyolefin, preferably having a weighted average molecular weight in the range of 5,000 kg / mol to 40,000 kg / mol, and 10% to 25% by weight of functional polymer selected from acid-grafted polyolefin, anhydride-grafted polyolefin, or combinations thereof; ii) heat the mixture to a temperature of 145 °C to 200 °C; iii) apply shear pressure to the heated mixture to bond the terminal end of a recycled polyolefin unit and the functional polymer to provide a recycled resin composition; and, iv) obtain the recycled resin composition; wherein the recycled polyolefin unit has an unsaturation at at least one terminal end and the terminal end of the recycled polyolefin unit is attached to the functional polymer and wherein the recycled resin composition has a weighted average molecular weight in the range of 10,000 kg / mol to 50,000 kg / mol.
[0077] During the process of forming the recycled resin composition, the functional group attacks the unsaturation present at the terminal end of the polyolefin unit and preferably follows the following reaction: Petition 870220088506, dated 09 / 27 / 2022, page 24 / 44 19 / 27 Stage I: Formation of acrylic acid radical PE grafted with acrylic acid Stabilized acrylic acid group (II) Heteroradical transfer Step 2: Radical propagation 1+ H | Homo radical transfer ru ru Heteroradical transfer Step 3: Coupling reaction (PCR — post-consumer recycled polyolefin) Fragment 2 PCR PCR coupled tPE) (pp; (iv) Petition 870220088506, dated 09 / 27 / 2022, p. 25 / 44 20 / 27
[0078] In summary, the reaction can be described as follows: Polyethylene (PE) PE grafted with acrylic acid at a processing temperature of 175 °C. (V)
[0079] According to a third aspect of the present invention, an article comprising the recycled resin composition according to the first aspect or obtainable according to the second aspect is disclosed. More preferably, the article includes from 50% to 100% by weight, more preferably from 50% to 99% by weight of the recycled resin composition according to the first aspect of the invention or obtainable according to the second aspect of the invention. Preferably, the article is a film or a molded article. In yet another embodiment, the article is a packaging product, wherein the packaging comprises from 50% to 100% by weight, more preferably from 50% to 99% by weight of the recycled resin composition of the first aspect or obtainable by the second aspect of the present invention.
[0080] According to a fourth aspect of the present invention, the revealed film is an extruded film comprising from 50% by weight to 100% by weight, more preferably from 50% by weight to 99% by weight of the recycled resin composition according to the first aspect of the invention or obtainable according to the second aspect of the invention.
[0081] The term “film” refers to a sheet-like material in which the length and width of the material greatly exceed the thickness of the material. Typically, films are about 0.5 mm thick or less. Petition 870220088506, dated 09 / 27 / 2022, page 26 / 44 21 / 27
[0082] Preferably, the extruded film can be single-layered or multi-layered. When the extruded film is multi-layered, at least one layer comprises the recycled resin composition. Additional ingredients
[0083] The recycled resin composition may include one or more additional components.
[0084] Examples of suitable additional components include, but are not limited to, an antioxidant, a foaming agent, a colorant, fillers, a pigment, a crosslinking agent, an inhibitor and / or an accelerator. At least one other conventional additive may be used, for example, enhancers, mold release agents, coating materials, humectants, plasticizers, sealing materials, thickening agents, diluting agents, binders and / or any other commercially available or conventional components.
[0085] Antioxidants are added to prevent polymer degradation during processing. An example is Naugard B25 (a mixture of tris(2,4-di-tert-butylphenyl))phosphine and tetrakismethylene ((3,5-di-tert-butyl-4-hydroxyhydrocinnamate)methane) from Chemtura Corporation.
[0086] The foaming agent is added to reduce the density of the resin composition by forming foam. Examples of foaming agents include Celogen TSH (toluene sulfonyl hydrazide), Celogen AZ (azodicarbonamide), Celogen OT (p-p'-oxybis(benzene sulfonyl hydrazide)), Celogen RA (p-toluene sulfonyl semicarbazide), Opex 80 (dinitrosopentamethylenetetramine), and Expandex 5-PT (5-phenyltetrazole) from Chemtura Corporation.
[0087] Colorants are pigments or dyes. Dyes are commonly organic compounds that are soluble in plastic, forming a neutral molecular solution. These produce intense, bright colors and are transparent. Pigments are generally insoluble in plastic. The color results from Petition 870220088506, dated 09 / 27 / 2022, page 27 / 44 22 / 27 dispersion of fine particles (in the range of about 0.01 to about 1 µm) throughout the thermoplastic (d). These produce opacity or at least some translucency in the cellulosic-thermoplastic composite. Pigments can be organic or inorganic compounds and are viable in various forms, including dry powders, color concentrates, liquids, and pre-colored resin pellets. The most common inorganic pigments include oxides, sulfides, chromates, and other complexes based on a heavy metal, such as cadmium, zinc, titanium, lead, molybdenum, iron, combinations thereof, and others. Ultramarines are typically sulfide-silicate complexes containing sodium and aluminum. Generally, pigments comprise mixtures of two, three, or more oxides of iron, barium, titanium, antimony, nickel, chromium, lead, and others in known ratios. Titanium dioxide is a widely used and well-known thermally stable bright white inorganic pigment.Other known organic pigments include azo or diazo pigments, pyrazolone pigments, permanent red 2B, nickel azo yellow, litho red, and scarlet pigment.
[0088] Crosslinking agents may optionally be added to strengthen the bonding between the recycled polyolefin, as described above, into a homogeneous end product. The crosslinking agent binds through the pendant hydroxyl groups to the polyolefin chain. The crosslinking agents must have the characteristics of forming a strong bond at relatively low temperatures. Examples of crosslinking agents that may be used include polyurethanes such as isocyanate, phenolic resin, unsaturated polyester resin, and epoxy, and combinations thereof. The phenolic resin may be any single-stage or two-stage resin, preferably with a low hexane content.
[0089] Inhibitors can be added to slow down the rate of the crosslinking reaction. Examples of known inhibitors include organic acids, for example, citric acid. Petition 870220088506, dated 09 / 27 / 2022, page 28 / 44 23 / 27
[0090] Accelerators can be added to increase the rate of the crosslinking reaction. Examples of accelerators include amine catalysts, for example, Dabco BDO (Air Products), and DEH40 (Dow Chemical).
[0091] The quantities of the various additional components in the composition may be adjusted by those skilled in the art depending on the specific materials being used and the intended use of the material.
[0092] Another type of component optionally present in the compositions of the present invention are reinforcing agents, in particular mineral fillers, such as talc or calcium carbonate, or fibers, such as glass fibers. Said reinforcing agents may, for example, be added in amounts of 5% to 50% by weight, based on the total weight of the composition.
[0093] To achieve higher levels of compatibility between the various polymeric components and with polar additives, such as fillers and fibers, when present, the compositions of the present invention may also comprise compatibilizing and / or coupling agents, preferably in amounts of 0.5 to 10% by weight, more preferably 0.5 to 5% by weight, based on the total weight of the composition.
[0094] Examples of these compatibilizing and / or coupling agents are polar functional PP resins with oxygenated groups, such as polypropylene grafted with maleic anhydride or with other compounds containing carboxylic groups, or polypropylene containing peroxide groups.
[0095] Other additives conventionally used in polyolefin compositions, such as pigments, stabilizers, biocidal agents, may also be present. Examples Example 1: Preparation of the recycled resin composition according to the present invention.
[0096] For the present study, a heavy quantity of recycled polyolefin (e.g., recycled Ecoplast NAV 102-LDPE) was dried for 6 hours at 800 °C before Petition 870220088506, dated 09 / 27 / 2022, page 29 / 44 24 / 27 of the processing. Four (4) different examples (as presented in Table 1) of the recycled resin composition according to the present invention and a comparative example (Ex. C) were prepared by adding recycled polyolefin and the functional polymer (acrylic acid grafted PE, Polybond™ 1009) in varying ratios in an extruder. The recycled polyolefin was added with the functional polymer (acrylic acid grafted PE) in the interlocking co-rotating twin-screw extruder equipped with a mixing screw configuration of L / D ratio of 32:1, where “L” means the length and “D” means the diameter of the screw. The screw speed throughout the experiment was maintained at 45 rpm.
[0097] The extruder temperature was gradually increased from 145 °C to 200 °C between the feeder and the die, while the molten mass was gradually transported by the interlocking co-rotating screw towards the die, where the heated mass was extruded into thin filaments and cut into pellets and then for 6 hours at 800 °C.
[0098] The recycled resin composition prepared according to the present invention in pellet form was collected to provide 4 different samples of the recycled resin composition. Example 2: Preparation of the injection-molded article from the recycled resin composition according to the present invention and evaluation of the mechanical properties of the article.
[0099] The pellets generated in Example 1 were then used in an injection molding process to prepare an article. The 4 different pellet examples from Example 1 were injected and molded to prepare an article conforming to sample type 1 according to ASTM 638D standard. During the injection molding process, the different recycled resin composition from Example 1 was placed in the feeder of the injection molding machine and the extruder temperature was increased from 81 °C to 200 °C and then the Petition 870220088506, dated 09 / 27 / 2022, pp. 30 / 44 25 / 27 heated mass was injected through an opening to form an injection-molded article.
[0100] The injection molding conditions were as follows: • Injection pressure - 60 bar • Retention pressure - 50 bar • Retention time - 5 seconds • Cooling time - 30 seconds.
[0101] The injection-molded article was then used to determine the mechanical properties of the various examples of the recycled resin composition prepared in Example 1 and provided in Table 1.
[0102] The properties of the injection-molded article prepared from virgin LLDPE (Ex. A) and from recycled polyolefin (Ex. B) were also measured and the observations were recorded and provided in Table 1 below. Table 1 Serial No. Virgin LLDPE (% by weight) Recycled Polyolefin (% by weight) Acrylic Acid Grafted PE (% by weight) Tensile Strength (MPa) Tensile Modulus (MPa) Elongation (%) Ex. A 100 0 0 12.13 487.89 > 250 Ex. B 0 100 0 13.95 393.85 246.78 Ex. C 0 95 5 13.13 378.6 191.5 Ex. 2 0 90 10 15.21 468.37 203.21 Ex. 3 0 85 15 14.64 441.25 205.7 Ex. 4 0 80 20 14.74 438.63 193.45 Ex. 5 0 75 25 14.56 422.57 188.21
[0103] The results presented in Table 1 show that the recycled polyolefin itself (Ex. B) had a high tensile strength value, but had inferior properties for tensile modulus and elongation when compared to LLDPE (Ex. A, virgin polyolefin). The addition of the functional polymer (PE grafted with acrylic acid) to the recycled polyolefin (Ex. 2 to Ex. 5) improves the mechanical properties compared to the recycled polyolefin. Petition 870220088506, dated 09 / 27 / 2022, pp. 31 / 44 26 / 27 (Ex. B). It was further observed that when the functional polymer is within the claimed ranges (Ex. 2 to Ex. 5), the mechanical properties are significantly improved compared to the comparative Ex. C where the functional polymer is outside the claimed range. Example 3: Evaluation of the molecular weight of the recycled resin composition prepared according to the present invention.
[0104] The molecular weight of the various samples of the resin composition having different levels of polyethylene grafted with acrylic acid was measured by computing the frequency sweep data within the Carreau-Yasuda equation and the results obtained were observed and presented in Table 2. The frequency sweep and molecular weight were determined using the ASTM D4440-15 method (Standard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology).
[0105] Carreau-Yasuda Model: a - affects the shape of the transition region; λ - time constant determines where it changes from constant to power law n - describes the slope of the power law ηο, η°ο - describes plateau viscosities Petition 870220088506, dated 09 / 27 / 2022, pp. 32 / 44 27 / 27 Table 2 Example Series Zero Shear Viscosity (Pa.s) Weighted Average Molecular Weight (kg / mol) 1 Ex. B 66900 10810 2 Acrylic Acid Grafted PE 56230 10280 3 Ex. C 10200 12480 4 Ex. 2 235400 15640 5 Ex. 3 1000005 28470
[0106] The results in Table 2 indicate that the examples according to the present invention (Ex. 2 and Ex. 3) show an increase in molecular weight compared to the recycled polyolefin (Ex. B). An increase in molecular weight in the examples according to the present invention (Ex. 2 and Ex. 3) is also accompanied by an increase in zero shear viscosity, which indicates that the increase in molecular weight is due to the bond formed between the functional polymer (PE grafted with acrylic acid) and the end-end saturation present in the recycled polyolefin. Example 3: NMR evaluation of recycled polyolefin.
[0107] A solid-state NMR (Philips 102023 spectrometer) was performed to detect the position of the unsaturation in the recycled polyolefin and the 13C NMR plot was obtained as shown in Figure 1.
[0108] The 13C NMR plot shows the presence of unsaturated functional moieties with peaks at positions 4 and 3. The peaks at 110 ppm and 135 ppm confirm the presence of unsaturation at the terminal position of the recycled polyolefin chains. All other peaks with greater lengths signify the ethylene chain of polyethylene and its chain linkage. Petition 870220088506, dated 09 / 27 / 2022, pp. 33 / 44
Claims
1 / 3 Claims 1. A method for preparing a recycled resin composition characterized by said method comprising the steps of: i) mixing recycled polyolefin and a functional polymer selected from acid-grafted polyolefin, anhydride-grafted polyolefin or combinations thereof to form a mixture; ii) heating the mixture to a temperature in the range of 145 °C to 200 °C; iii) applying shear pressure to the heated mixture to bond the terminal end of a recycled polyolefin unit and the functional polymer to form the recycled resin composition; and, iv) obtaining the recycled resin composition comprising from 10% by weight to 25% by weight of functional polymer, and from 5% by weight to 90% by weight of recycled polyolefin;wherein the recycled polyolefin unit has an unsaturation at at least one terminal end, and the terminal end of the recycled polyolefin unit reacts with, and is linked with, a carboxyl or anhydride group of the functional polymer, and wherein the recycled resin composition has a weighted average molecular weight in the range of 10,000 kg / mol to 50,000 kg / mol.
2. Method according to claim 1, characterized in that the recycled polyolefin has a weighted average molecular weight in the range of 5,000 kg / mol to 40,000 kg / mol.
3. Method according to claim 1, characterized by the recycled polyolefin composition comprising: i) from 5% by weight to 90% by weight of recycled polyolefin; ii) from 10% by weight to 25% by weight of functional polymer selected from anhydride-grafted polyolefin, acid-grafted polyolefin or combinations thereof; wherein the recycled polyolefin unit has an unsaturation at at least one terminal end, and the terminal end of the recycled polyolefin unit reacts with, and is linked with, a carboxyl or anhydride group of the functional polymer, and wherein the recycled resin composition has a weighted average molecular weight of 10,000 kg / mol to 50,000 kg / mol.
4. Method according to claim 1, characterized in that the recycled polyolefin unit has unsaturation present at both terminal ends.
5. Method according to claim 1, characterized in that at least 60% by weight of the recycled polyolefin unit comprises an unsaturation present at the terminal end.
6. A method, according to any of the preceding claims, characterized in that a functional polymer unit is attached to the terminal end of two recycled polyolefin units.
7. A method, according to any of the preceding claims, characterized in that the functional polymer has a pendant carboxyl group capable of forming a chemical bond with a terminal-end unsaturation of the recycled polyolefin via the terminal hydroxyl groups of the functional polymer, preferably the chemical bond is a covalent bond.
8. A method, according to any of the preceding claims, characterized in that at least 60%, more preferably at least 80% by weight of the recycled polyolefin is bonded with the functional polymer in the recycled resin composition.
9. A method, according to any of the preceding claims, characterized in that the recycled polyolefin is a mixed polyolefin comprising at least 80% by weight of LLDPE, LDPE and HDPE.
10. A method, according to any of the preceding claims, characterized in that the functional polymer is a polyethylene grafted with acrylic acid, polyethylene grafted with maleic anhydride, or combinations thereof.
11. A method, according to any of the preceding claims, characterized in that the functional polymer is an acrylic acid-grafted LDPE, acrylic acid-grafted LLDPE, acrylic acid-grafted HDPE, or combinations thereof. Petition 870220088506, dated 09 / 27 / 2022, p. 35 / 44 3 / 3 12. A method, according to any of the preceding claims, characterized in that the functional polymer has from 3% by weight to 8% by weight of the acid or anhydride functional group, based on the weight of the functional polymer.
13. A method, according to any of the preceding claims, characterized in that the polymeric portion of the functional polymer has a weighted average molecular weight of 10,000 to 30,000 kg / mol.
14. Recycled resin composition characterized by being obtained by the method as defined in any one of claims 1 to 13.
15. Article characterized by comprising the recycled resin composition as defined in claim 14.
16. Article according to claim 15, characterized in that the article is a film or molded article preferably comprising from 50% by weight to 100% by weight of the recycled resin composition as defined in claim 14. Petition 870220088506, dated 09 / 27 / 2022, pp. 36 / 44