Articles and methods made from recycled materials containing adhesives

Abstract

This disclosure provides a method. In one embodiment, the method includes the step of preparing pellets of recycled spent material. The recycled spent material is formed from a multilayer structure comprising at least (i) a layer composed of an olefin polymer and (ii) an adhesive layer. The adhesive layer comprises a solvent-free polyurethane adhesive composition. The method includes the step of blending the pellets with an olefin polymer blend component to form a blended material. The method includes the step of forming an article from the blended material. This disclosure also provides an article produced by the method.

Description

[Technical Field]

[0001] The environmental hazards caused by plastic waste are well known. Large-scale social initiatives have been adopted to recycle and reuse plastic materials, which are referred to herein as recycled nonvirgin material. Attempts to reprocess recycled nonvirgin material and reincorporate it into usable consumer goods continue to expand. [Background technology]

[0002] However, it has been found that articles made from recycled used materials may have inferior physical properties. Film-based articles formed from recycled used materials, in particular, have insufficient tear strength, tensile strength, and / or dirt impact strength. Recycled used materials made from packaging materials containing adhesives (laminated and / or coated articles) are especially difficult to recycle because the adhesives adversely affect the physical properties of the recycled articles. Efforts to form film-based articles with appropriate physical properties from recycled used materials containing solvent-free polyurethane adhesives have not yet been fully successful.

[0003] In this technical field, there is a recognized need for polymer compositions containing solvent-free polyurethane adhesives that, when recycled, can produce recycled articles with appropriate physical properties compared to recycled articles produced from olefin-based polymer materials that do not contain solvent-free polyurethane adhesives. Furthermore, there is a need for polymer films / laminates containing a solvent-free polyurethane adhesive layer that, when recycled, can produce film-type articles with appropriate tear strength, tensile strength, and / or dirt impact strength. [Overview of the Initiative]

[0004] This disclosure provides a method. In one embodiment, the method includes the step of preparing pellets of recycled used material. The recycled used material is formed from a multilayer structure comprising at least (i) a layer composed of an olefin polymer and (ii) an adhesive layer. The adhesive layer comprises a solvent-free polyurethane adhesive composition. The method includes the step of blending the pellets with an olefin polymer blend component to form a blended material. The method includes the step of forming an article from the blended material.

[0005] This disclosure provides articles. In one embodiment, the article comprises an olefin polymer blend component and recycled used material. The recycled used material is formed from a multilayer structure comprising at least (i) a layer composed of an olefin polymer and (ii) an adhesive layer. The adhesive layer comprises a solvent-free polyurethane adhesive composition. [Modes for carrying out the invention]

[0006] definition All references to the periodic table of elements shall refer to the periodic table of elements published by CRC Press, Inc., 1990–1991. References to element groups in this periodic table shall follow the new notation for group numbering.

[0007] For the purposes of U.S. patent practice, the content of any referenced patent, patent application, or publication is incorporated by reference in whole, particularly with respect to the disclosure of definitions (to the extent that it does not conflict with any definition specifically provided herein) and general knowledge in the art (or equivalent U.S. editions thereof).

[0008] The numerical ranges disclosed herein include all values ​​from the lower limit to the upper limit, including the lower and upper limits. For ranges containing obvious values ​​(e.g., 1 or 2, or 3 to 5, or 6 or 7), any lower ranges between any two obvious values ​​are also included (e.g., the above range 1 to 7 includes the lower ranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6, etc.).

[0009] Unless otherwise stated, by contextual implication or by practice in the art, all parts and percentages are based on weight, and all test methods are current as of the filing date of this disclosure.

[0010] The terms "adhesive" or "adhesive composition" refer to a composition that adheres to at least one substrate. An adhesive composition can be used as a coating layer on a substrate or as an adhesive layer between two or more substrates in a laminate.

[0011] The terms “blend” or “polymer blend,” as used herein, refer to a blend of two or more polymers. Such a blend may or may not be miscible (i.e., it does not undergo phase separation at the molecular level). Such a blend may or may not undergo phase separation. Such a blend may or may not contain one or more domain configurations as determined by transmission electron spectroscopy, light scattering, X-ray scattering, and other methods known in the art.

[0012] The terms "coating" or "coating composition" refer to an adhesive composition that adheres to a single surface of a substrate or film. A coating is the outermost layer of a substrate or film. A coated article has a coating, which is the outermost (or innermost) layer containing the adhesive composition. A coated article is different from a laminate where the adhesive composition is placed between film / substrate layers, or otherwise sandwiched between film / substrate layers.

[0013] The term "composition" refers to a composition, as well as a mixture of materials including reaction products and decomposition products formed from the materials of the composition.

[0014] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the existence of any additional components, steps, or procedures, whether or not they are specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term “comprising” may include any additional additives, adjuvants, or compounds, whether polymers or not, unless otherwise stated. In contrast, the term “consisting essentially of” excludes any other components, steps, or procedures from the scope of any subsequent description, except for components, steps, or procedures that are not essential to the feasibility. The term “consisting of” excludes any components, steps, or procedures that are not specifically delineated or enumerated. The term “or” refers to the individually enumerated members and any combination thereof, unless otherwise stated. The use of the singular includes the use of the plural, and vice versa.

[0015] An "ethylene-based polymer" is a polymer containing more than 50 weight percent (wt%) of polymerized ethylene monomer (relative to the total amount of polymerizable monomers), and optionally containing at least one comonomer. Ethylene-based polymers include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and units derived from one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" are interchangeable. Non-limiting examples of ethylene-based polymers (polyethylene) include low-density polyethylene (LDPE) and linear polyethylene. Non-limiting examples of linear polyethylene include linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (ULDPE), very low-density polyethylene (VLDPE), multi-component ethylene-based copolymers (EPE), ethylene / α-olefin multi-block copolymers (also known as olefin block copolymers (OBC)), substantially linear or linear plastomers / elastomers, and high-density polyethylene (HDPE). Generally, polyethylene can be produced in gas-phase fluidized bed reactors, liquid-phase slurry process reactors, or liquid-phase solution process reactors using heterogeneous catalyst systems such as Ziegler-Natta catalysts, or homogeneous catalyst systems containing Group 4 transition metals and ligand structures, such as metallocenes, non-metallocene metal centers, heteroaryls, heterovalent aryloxyethers, phosphine imines, etc. Combinations of heterogeneous and / or homogeneous catalysts can also be used in either single-reactor or double-reactor configurations.

[0016] High-density polyethylene (or "HDPE") is a C4-C64 polyethylene. 10α-olefin comonomers, or C4-C8 α-olefin comonomers, and ethylene homopolymers or ethylene / α-olefin copolymers having densities of 0.940 g / cc, 0.945 g / cc, 0.950 g / cc, 0.953 g / cc-0.955 g / cc, 0.960 g / cc, 0.965 g / cc, 0.970 g / cc, 0.975 g / cc, or 0.980 g / cc. HDPE may be a unimodal copolymer or a multimodal copolymer. A "unimodal ethylene copolymer" has one distinct peak in gel permeation chromatography (GPC) showing the molecular weight distribution of ethylene / C4-C8 α-olefin comonomers. 10 It is an α-olefin copolymer. A "multimodal ethylene copolymer" is defined as an ethylene / C4-C copolymer that has at least two distinct peaks in the GPC showing its molecular weight distribution. 10 These are α-olefin copolymers. Multimodality includes copolymers with two peaks (bimodality) and copolymers with more than two peaks. Non-limiting examples of HDPE include ELITE® 5960G1 High Density Polyethylene (HDPE) Resin (available from The Dow Chemical Company), DOW® High Density Polyethylene (HDPE) Resin (available from The Dow Chemical Company), CONTINUUM® Bimodal Polyethylene Resin (available from The Dow Chemical Company), LUPOLEN® (available from LyondellBasell), and HDPE products from Borealis, Ineos, and ExxonMobil.

[0017] "Low-density polyethylene" (or "LDPE") is an ethylene homopolymer, or at least one C3-C3 polymer. 10LDPE consists of ethylene / α-olefin copolymers containing α-olefins, has a density of less than 0.915 g / cc to less than 0.940 g / cc, contains long-chain branching, and has a wide MWD. ​​LDPE is typically produced by high-pressure free-radical polymerization (carried out in a tubular reactor or autoclave using a free-radical initiator). Non-limiting examples of LDPE include AGILITY® 1021 Low Density Polyethylene (LDPE) Resins (available from The Dow Chemical Company), MarFlex® (Chevron Phillips), LUPOLEN® (LyondellBasell), and LDPE products from Borealis, Ineos, ExxonMobil, and other companies.

[0018] "Linear low-density polyethylene" (or "LLDPE") is defined as a unit derived from ethylene and at least one C3-C3 compound. 10 LLDPE is a linear ethylene / α-olefin copolymer containing a heterogeneous distribution of short-chain branches, including units derived from α-olefin comonomers. In contrast to conventional LDPE, LLDPE is characterized by having little to no long-chain branches. LLDPE has a density of less than 0.910 g / cc to 0.940 g / cc. Non-limiting examples of LLDPE include ELITE® 5400G linear low-density polyethylene resin (available from The Dow Chemical Company), TUFLIN® linear low-density polyethylene resin (available from The Dow Chemical Company), DOWLEX® polyethylene resin (available from the Dow Chemical Company), FINGERPRINT® polyethylene resin (available from the Dow Chemical Company), and MARLEX® polyethylene (available from Chevron Phillips).

[0019] An "olefin-based polymer" or "polyolefin" is a polymer containing a majority or more than 50% by weight of polymer-derived polymerized olefin monomers, such as ethylene or propylene, and may optionally contain at least one comonomer. Non-limiting examples of olefin-based polymers are ethylene-based polymers and propylene-based polymers.

[0020] "Plastic" typically refers to polymer materials that can be molded or shaped when subjected to heat and / or pressure. Non-limiting examples of plastics include ethylene-based polymers and propylene-based polymers. Plastics do not include glass, metal, and / or wood or other cellulosic materials (i.e., paper-based materials).

[0021] A “polymer” is a polymer compound prepared by polymerizing monomers, whether of the same or different types. Therefore, the general term polymer encompasses the terms “homopolymer” (used to refer to a polymer prepared from only one type of monomer, although it should be understood that trace amounts of impurities may be incorporated into the polymer structure) and “interpolymer.” Trace amounts of impurities, such as catalyst residues, may be incorporated into and / or within the polymer. “Polymer” also encompasses all forms of copolymers, such as random copolymers and block copolymers. The terms “ethylene / α-olefin polymer” and “propylene / α-olefin polymer” refer to copolymers, as described above, prepared by polymerizing ethylene or propylene with one or more additional, polymerizable α-olefin monomers, respectively. Polymers are often described as "made from" one or more specified monomers, "based on" specified monomers or monomer types, or "containing" specified monomer content. It should be noted that in this context, the term "monomer" is understood to refer to the polymerized residues of the specified monomers, not the unpolymerized species. Generally, in this specification, polymers are described as being based on "units" of the polymerized forms of the corresponding monomers.

[0022] "Polyurethane" is a polymer having polyurethane bonds derived from the chemical reaction between isocyanate groups and polyols. Chemical substances holding isocyanate groups and polyols can have many different compositions. For example, one or more isocyanate-terminated polymers can be reacted with small molecule polyols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, and combinations thereof to produce polyurethane polymers. Alternatively, one or more hydroxyl-terminated polymers can be reacted with small molecule isocyanates such as toluene diisocyanate (TDI), 4,4'-methylenebisphenyl isocyanate (MDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), 4,4'-methylenedicyclohexyl diisocyanate, 1,5-naphthylene diisocyanate, 1,3-bis(isocyanatomethyl)benzene, dimers and trimers of these isocyanates, and combinations thereof to produce polyurethane polymers. Further alternatively, one or more hydroxyl-terminated polymers can be reacted with one or more isocyanate-terminated polymers to produce polyurethane polymers. As the general skeletons of the hydroxyl and isocyanate-terminated polymers used for the synthesis of polyurethane, polyester, polyether, polycarbonate, poly(meth)acrylate, polyamide, nylon, and silicone can be mentioned. Polyurethane can be linear or crosslinked.

[0023] "Propylene-based polymer" is a polymer containing more than 50 weight percent of polymerized propylene monomer (relative to the total amount of polymerizable monomers) and optionally containing at least one comonomer. The terms "propylene-based polymer" and "polypropylene" can be used interchangeably.

[0024] The terms "recyclability" or "mechanical recyclability" are referred to in this specification with respect to a first material or article having an adhesive or coating, and mean that it is mechanically recyclable or has the potential for recycling; the first material or article having an adhesive or coating can be mechanically reprocessed to produce a second material or article having a desired range of physical properties, and this second article has a change in mechanical or physical properties of at least 33% or less compared to the performance of a control material or control article that has been reprocessed in the same manner as the second article without including either the adhesive or the coating. An example of a test method and guidelines for determining the recyclability of plastic articles can be found, but is not limited to, in the publication "Critical Guidance Protocol for PE Film and Flexible Packaging", Document Number FPE-CG-01, Revision Date August 2, 2022, The Association of Plastic Recyclers (APR).

[0025] "Ultra-low density polyethylene" (or "ULDPE") and "Very-low density polyethylene" (or "VLDPE") are each linear ethylene / α-olefin copolymers containing a heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3-C 10 α-olefin comonomer. ULDPE and VLDPE each have a density of 0.885 g / cc to 0.915 g / cc. Non-limiting examples of ULDPE and VLDPE include AFFINITY(tm) PL 1850G ultra linear low density polyethylene resin (available from The Dow Chemical Company), ATTANE(tm) ultra low density polyethylene resin (available from The Dow Chemical Company) and FLEXOMER(tm) very low density polyethylene resin (available from The Dow Chemical Company).

[0026] Test Method Density is measured according to ASTM D792, Method B. Results are reported in grams per cubic centimeter (g / cc).

[0027] Differential scanning calorimetry (DSC) can be used to measure the melting, crystallization, and glass transition behavior of polymers over a wide temperature range. For example, this analysis is performed using a TA Instruments Q1000 DSC equipped with an RCS (refrigerated cooling system) and an autosampler. A nitrogen purge gas flow of 50 ml / min is used during the test. Each sample is melted and compressed at approximately 175°C to form a thin film. The molten sample is then air-cooled to room temperature (approximately 25°C). Samples of 3–10 mg, 6 mm in diameter are taken from the cooled polymer, weighed, placed in a light aluminum dish (approximately 50 mg), and sealed. The analysis is then performed to determine its thermal properties.

[0028] The melting point Tm is determined from the DSC heating curve by first drawing a baseline between the start and end points of the melt transition. Then, a tangent line is drawn to the lower temperature data of the melt peak. The point where this tangent line intersects the baseline is the extrapolated melt start point (Tm). This is described in Bernhard Wunderlich, The Basis of Thermal Analysis, in Thermal Characterization of Polymeric Materials 92, 277-278 (Edith A. Turi ed., 2d ed. 1997).

[0029] The crystallization temperature Tc is determined from the DSC cooling curve in the same way as above, except that the tangent is drawn on the high-temperature side of the crystallization peak. The point where this tangent intersects the baseline is the extrapolated crystallization start point (Tc).

[0030] The glass transition temperature (Tg) is determined from the DSC heating curve as the point at which half of the sample acquires the heat capacity of a liquid, as described in Bernhard Wunderlich, *The Basis of Thermal Analysis, in Thermal Characterization of Polymeric Materials* 92, 278-279 (Edith A. Turi ed., 2d ed. 1997). The baselines are drawn below and above the glass transition region and extrapolated through the Tg region. Tg is the temperature at which the heat capacity of the sample is midway between these baselines.

[0031] The melt index (MI) (I2) is measured according to ASTM D1238 (190°C / 2.16kg), and the result is reported in grams per 10 minutes (g / 10 min) or decigrams per minute (dg / min). The melt index (I10) is measured according to ASTM D1238 (190°C / 10kg), and the result is reported in g / 10 min. The melt index ratio (I10 / I2) is measured according to ASTM D1238 at a temperature of 190°C, and is the ratio of the values ​​obtained at 10kg and 2.16kg.

[0032] Tear strength is measured according to ASTM D1922, and the results are reported in grams-weight (gf).

[0033] Tensile strength is measured according to ASTM D882, and the results are reported in kilopounds per square inch (ksi).

[0034] Tensile elongation is measured according to ASTM D882, and the results are reported as a percentage (%).

[0035] Dirt impact strength is measured according to ASTM D1709A, and the results are reported in Newtons (N) for force or in Joules (J) for energy.

[0036] Film haze is measured according to ASTM D1709A, and the results are reported as a percentage (%).

[0037] Detailed explanation This disclosure provides a method. In one embodiment, the method includes the step of preparing pellets of recycled used material. The recycled used material is formed from a multilayer structure. The multilayer structure includes (i) a layer composed of an olefin polymer and (ii) an adhesive layer. The adhesive layer includes a solvent-free polyurethane adhesive composition. The method includes the steps of blending the pellets of recycled used material with an olefin polymer blend component to form a blended material, and forming an article from the blended material.

[0038] This method includes the step of preparing pellets of recycled spent material. The term “recycled spent material,” as used herein, includes particles of polymer materials recycled from consumer plastics and / or industrial plastics, referred to as post-consumer recycled polymer materials (“PCR”) and post-industrial recycled polymer materials (“PIR”). Non-limiting examples of such PCR / PIR articles include polymer materials used as plastic consumer articles and / or plastic industrial articles, previously used in the context of single-layer films, multi-layer films, and laminates, such as plastic packaging materials, pipes, fibers, industrial waste, or molded products for consumer or industrial use. In other words, recycled spent material is formed from waste plastic and may contain trace amounts of paper (from labels), ink, etc. Recycled spent material is reprocessed plastic material recovered after the plastic material has completed its initial use; i.e., plastic articles that have already served their original purpose. Recycled spent material is typically recovered from recycling programs and / or recycling plants. Used materials intended for recycling typically require additional cleaning and processing before they can be reintroduced into the production line.

[0039] This method includes the step of preparing pellets of recycled used material. The recycled used material is formed from a multilayer structure. As used herein, a “multilayer structure” has (i) layers composed of an olefin polymer, (ii) an adhesive layer composed of a solvent-free polyurethane adhesive composition, and (iii) an optional additional layer. The multilayer structure may be a laminated article comprising at least one olefin polymer layer and at least one adhesive layer that adheres the olefin polymer layer to another layer. Alternatively, the multilayer structure may be a coated article comprising at least one adhesive layer applied as a coating (or coating layer) to the surface of an olefin polymer substrate.

[0040] In one embodiment, the multilayer structure from which the recycled used material is formed is a multilayer film, for example, a waste film used in consumer food packaging. The multilayer film has layers composed of olefin polymers. The olefin polymer can be an ethylene polymer or a propylene polymer. In a further embodiment, the olefin polymer for the layers is one or more ethylene polymers. Non-limiting examples of suitable ethylene polymers include ethylene homopolymers or ethylene / α-olefin copolymers. Ethylene copolymers are ethylene / C3-C 12 These are α-olefin copolymers or ethylene / C4-C8 α-olefin copolymers. Non-limiting examples of comonomers suitable for ethylene / α-olefin copolymers include propylene, butene, hexene, and octene. 12 The α-olefin copolymer (or ethylene / C4-C8α-olefin copolymer) can be MDPE, LDPE, LLDPE, ULDPE, VLDPE, HDPE, or combinations thereof. The layer having the olefin polymer may include, but is not limited to, one or more additives, including slip agents, anti-blocking agents, and combinations thereof. The multilayer film may be a laminated article or a coated article, as previously discussed herein.

[0041] The multilayer structure (from which recycled used material is formed) also includes at least one adhesive layer. The adhesive layer is composed of a solvent-free polyurethane adhesive composition. The adhesive may be an adhesive layer in a laminate, or a coating layer on a film or substrate. The solvent-free polyurethane adhesive composition may optionally contain one or more components, such as fillers, dyes and pigments, tackifiers, plasticizers, rheological modifiers, polymers (e.g., thermoplastic resins other than those discussed above herein), dehydrating agents (e.g., silanes), benzoyl chloride, other polyols (e.g., aliphatic polyols), and ultraviolet indicators.

[0042] Without being limited to any particular theory, the recyclability of a multilayer structure containing a layer of olefinic polymer (ethylene polymer) and an adhesive layer of a solvent-free polyurethane adhesive composition can be determined by comparing the Hansen solubility parameter (HSP) and aliphatic carbon ratio (ACR) of the solvent-free polyurethane adhesive composition with their respective thresholds. The "Hansen solubility parameter" (or "HSP"), as used herein, is a set of physicochemical parameters of a substance that can be used to predict the type of interactive forces responsible for the compatibility between a substance and another material. The basis for HSP is that the cohesive energy of two substances can be estimated by the sum of London dispersion forces, intermolecular dipole interactions, and hydrogen bonding interactions. HSP values ​​are available in DW van Krevelen's book "Properties of Polymers," 4th edition, fully revised, Elsevier: Amsterdam, 2009, ebook ISBN: 9780080915104. The term “aliphatic carbon ratio” (or “ACR”), as used herein, is defined as the ratio of the total number of moles of aliphatic carbons (methyl (CH3), methylene (CH2), methine (CH), quaternary carbon (C), and alkene carbon (C=C) groups) in a substance or mixture of substances to the number of moles of the substance or mixture of substances. Generally, the higher the ACR, the more chemically similar the adhesive or coating composition is to a hydrocarbon and the more likely it is to be a mechanically recyclable composition in polyolefin polymers. As a non-limiting example, for 0.034 moles of 2-phenylethanol (C6H5CH2CH2OH), there are 0.068 moles of aliphatic carbons (two CH2 functional groups in one molecule). Therefore, the ACR of this compound is 0.068 / 0.034 = 2. Applying the same calculation to “ADCOTE® 102E / CoreactantCT” in a mixed weight ratio of 100:5.2 yields an ACR of 2.48.

[0043] In the context of solvent-free polyurethane adhesive compositions, a multilayer structure containing a solvent-free polyurethane adhesive composition is more likely to be recyclable (or become recyclable) than not recyclable if (i) the HSP of the solvent-free polyurethane adhesive composition is 22.7 or less, and (ii) the ACR of the solvent-free polyurethane adhesive composition is 6.9 or more. More specifically, in the context of solvent-free polyurethane adhesive compositions, having both an HSP value of 22.7 or less and an ACR value of 6.9 or more results in a probability of over 75% (or 100%) that recycled used material formed from a multilayer structure having a layer of olefin polymer (ethylene polymer) and an adhesive layer composed of a solvent-free polyurethane adhesive composition will be recyclable into a film-based article with appropriate physical properties. Conversely, in the context of solvent-free polyurethane adhesive compositions, a multilayer structure having a layer of olefinic polymer (ethylene polymer) and an adhesive layer composed of a solvent-free polyurethane adhesive composition that satisfies only one of (i) an HSP value of 22.7 or less or (ii) an ACR value of 6.9 or more (or neither) results in a probability of less than 50% (or 0% probability) that recycled used material having a solvent-free polyurethane adhesive composition can be recycled into a film-based article with appropriate physical properties. The selection of a solvent-free polyurethane adhesive to increase the probability of recyclability in recycled used material is described in U.S. Patent Application Publication No. 63 / 482,099, “A Method for Modeling Chemical Compatibility of Chemical Species with Polyethylene” (Agent Reference Number: 84969-US-PSP), filed on 30 January 2023, and the entire content of which is incorporated herein by reference.

[0044] In one embodiment, the method includes selecting a solvent-free polyurethane adhesive composition for the adhesive layer (for a multilayer structure) having an aliphatic carbon ratio (ACR) of 6.9 or higher and a Hansen solubility parameter (HSP) value of 22.7 or lower. The selection of the solvent-free polyurethane adhesive composition having the above-mentioned ACR and HSP values ​​is performed at the time the multilayer film structure is formed.

[0045] In one embodiment, the solvent-free polyurethane adhesive composition for recycled used materials for reproduction is a solvent-free polyurethane adhesive composition having a polyol component and an isocyanate curing component. The polyol component is a blend of a polyether polyol and a polyester polyol. One non-limiting example of such a polyol component is PACACEL™ L75-191 (available from The Dow Chemical Company). One non-limiting example of such an isocyanate curing component is MOR-FREE™ C33 (available from The Dow Chemical Company). The solvent-free polyurethane adhesive composition composed of PACACEL™ L75-191 and CR88-141 (and optional additives) exhibits an HSP value of 22.7 or less and an ACR value of 6.9 or more. More specifically, the solvent-free polyurethane adhesive composed of PACACEL™ L75-191 and CR88-141 (and optional additives) exhibits an HSP value of 22.5 or less and an ACR value of 14.0 or more. Therefore, the solvent-free polyurethane adhesive composed of PACACEL™ L75-191 and CR88-141 (and optional additives) has a probability of more than 75% (or a 100% probability) that the recycled used material for reproduction formed from a multilayer structure having a layer of an olefin-based polymer (ethylene-based polymer) and an adhesive layer composed of PACACEL™ L75-191 and CR88-141 (and optional additives) can be successfully recycled into a film-based article having appropriate physical properties.

[0046] The multilayer structure (from which the recycled used material for reproduction is formed) may include one, two, three, four, five, six, seven or more additional layers, each of these layers being composed of an olefin-based polymer (i.e., an ethylene-based polymer). For each additional layer, ethylene / C3~C 12 The α-olefin copolymer (or ethylene / C4~C8 α-olefin copolymer) is any ethylene / C3~C previously disclosed herein 12It may also be an α-olefin copolymer (or ethylene / C4~C8 α-olefin copolymer). It is understood that the multilayer structure may also include one, two, three, four, five, six, seven or more additional adhesive layers of the solvent-free polyurethane adhesive layer composition.

[0047] In one embodiment, the recycled used material formed from a multilayer structure contains ethylene polymers (unused ethylene polymers and non-used ethylene polymers) in a ratio of 99.5% to 80% by weight, or 99.5% by weight, or 99% by weight, or 98% by weight, or 97% by weight, or 96% by weight, or 95% by weight, or 94% by weight, or 93% by weight, or 92% by weight, or 91% by weight, or 90% by weight, 90% by weight, or 89% by weight, or 88% by weight, or 87% by weight, or 86% by weight, or 85% to 84% by weight, or 83% by weight, or 82% by weight, or 81% by weight. It contains, in amounts of % by weight, or 80% by weight, and a complementary amount of solvent-free polyurethane adhesive composition (in amounts such as obtaining 100% by weight of recycled used material) or 0.5% to 20% by weight, or 0.5% by weight, or 1% by weight, or 2% by weight, or 3% by weight, or 4% by weight, or 5% by weight, or 6% by weight, or 7% by weight, or 8% by weight, or 9% by weight, or 10% by weight, or 11% by weight, or 12% by weight, 13% by weight, or 14% by weight, or 15% by weight, or 16% by weight, or 17% by weight, or 18% by weight, or 19% by weight, or 20% by weight of water-based adhesive composition. Weight percentages are based on the total weight of recycled used material.

[0048] In one embodiment, the solvent-free polyurethane adhesive composition may be an internal adhesive layer of a laminate. The adhesive layer can improve interlayer adhesion between functional layers of olefin polymers and prevent delamination of the multilayer structure. In another embodiment, the solvent-free polyurethane adhesive composition may be included in an outer layer, for example, a coating layer of a coated article. The coating layer can provide mechanical support and protection for other layers of the coated article. Furthermore, the outer layer of the solvent-free polyurethane adhesive composition of a coated article may be particularly well suited for protection, engraving, and / or printing.

[0049] In one embodiment, the method includes the step of pelletizing a multilayer structure to form pellets of recyclable spent material. The multilayer structure is a consumer and / or industrial article that has been subjected to a molding process and has completed its initial purpose, as previously disclosed. The multilayer structure (i.e., a multilayer film having layers of an olefin polymer (ethylene polymer) and an adhesive layer having a solvent-free polyurethane adhesive composition (ACR ≥ 6.9 and HSR ≤ 22.7)) is crushed, flakebed, or otherwise pulverized and pelletized to form recyclable spent material. Pelleting may include the step of crushing or flakebed the multilayer structure to form flakes. The method may further include the step of densifying the flakes to form pellets of recyclable spent material. In one embodiment, a multilayer structure having at least (i) an olefin polymer (ethylene polymer) and (ii) an adhesive layer having a solvent-free polyurethane adhesive composition is subjected to a pelletizer unit capable of converting the multilayer structure into pellets of recyclable spent material.

[0050] This method includes the step of blending pellets of recycled used material with an olefin-based polymer blend component to form a blended material. The olefin-based polymer blend component may be in the form of pellets, flakes, or a combination thereof.

[0051] Olefin polymer blend components consist of (i) olefin polymer multilayer films for recycling, (ii) unused ethylene polymers, and (iii) combinations thereof. Olefin polymer blend components differ from pellets of recycled spent materials in that the materials / structures from which the olefin polymer blend components are formed do not contain an adhesive layer or contain adhesive within it. In particular, olefin polymer blend components lack or have had solvent-free polyurethane adhesive compositions removed.

[0052] In one embodiment, the olefin polymer blend component is a regenerated olefin multilayer film. The regenerated olefin multilayer film for the olefin polymer blend component may be the same multilayer film as the multilayer structure, except that the regenerated olefin multilayer film for the olefin polymer blend component does not contain an adhesive layer or any other adhesive. In a further embodiment, the regenerated olefin multilayer film is a regenerated ethylene multilayer film, and each layer of this regenerated olefin multilayer film contains only a regenerated ethylene polymer (and an optional additive) (or consists only of a regenerated ethylene polymer).

[0053] In one embodiment, the olefin polymer blend component is an unused olefin polymer. As used herein, “unused olefin polymer” means one or more olefin polymers that do not contain PCR and / or PIR. The unused olefin polymer has not been subjected to a molding process for forming an article for its first use (other than the formation of the first pellet after polymerization).

[0054] In further embodiments, the unused olefin polymer is an unused ethylene polymer. The unused ethylene polymer differs from the non-unused ethylene polymer in that it does not contain resin particles recycled from post-consumer or post-industrial articles. For example, the unused ethylene polymer is not a reprocessed material recovered after the material has completed its initial use, i.e., after it has already fulfilled its initial purpose.

[0055] In one embodiment, the blended material contains 1% to 99% by weight, or 1% to 75% by weight, or 1% by weight, or 2.5% by weight, or 5% by weight, or 10% by weight, or 15% by weight, or 20% by weight, or 30% by weight, or 40% by weight, or 50% by weight, or 60% by weight, or 70% by weight, or 75% by weight of recycled used material and a complementary amount of olefin polymer blend component (enough to obtain 100% by weight of the blended material), or 99% to 1% by weight, or 99% to 25% by weight, or 99% by weight, or 97.5% by weight, or 95% by weight, or 90% by weight, or 85% by weight, or 80% by weight, or 70% by weight, or 60% by weight, or 50% by weight, or 40% by weight, or 30% by weight, or 25% by weight of olefin polymer blend component. The weight percentages are relative to the total weight of the blended material.

[0056] In one embodiment, the blended material contains 50% by weight pellets formed from recycled used material and 50% by weight pellets of an olefin-based polymer blend component. The weight percentages are relative to the total weight of the blended material.

[0057] Next, the olefin polymer blend components are transferred to the feed zone of an extruder. This extruder is designed to densify and melt pellets of both the recycled spent material and the olefin polymer blend components to form a molten pool of polymer. This pool of polymer can be pressurized and extruded from the extruder through a die, converting the polymer into solid pellets. The term “extrude” or “purging” refers to the process of introducing a polymer into an extruder and propelling the polymer along a screw through a region of high temperature and pressure, where the polymer is melted and compressed, and finally extruded through a die. The extruder may be a single-screw extruder, a multi-screw extruder, a disc extruder, or a ram extruder. This method may also include the step of extruding pellets of the blended material to form an extruded product.

[0058] The method includes the step of forming an article from an extruded material (an extruded material of a blend). Since the article contains recycled used material, the article is a recycled article. The method includes the step of forming recycled articles from an extruded material (an extruded material of a blend), namely (recycled) pellets, (recycled) single-layer films, (recycled) multi-layer films, (recycled) laminates, (recycled) plastic packages, (recycled) pipes, (recycled) fibers, (recycled) molded products, and any combination thereof.

[0059] In one embodiment, the forming step includes molding an extruded material (an extruded blend of materials) into a molded article. The terms “molding” or “molded,” as used herein, refer to the process of melting a polymer, forming an extruded material, and then placing this extruded material into a mold (the mold being the inverse of the desired shape) to form an article (or part) of the desired shape and size. Molding may be unpressurized or pressurized.

[0060] In one embodiment, the method includes the step of injection molding an extruded material (formed from molten pellets of blended material) to form an injection-molded article. The term "injection molding," as used herein, refers to the process of melting a polymer material and injecting it under high pressure into a mold (the mold being the inverse of the desired shape) to form an article of a desired shape and size. The mold may be made of metal, such as steel and aluminum.

[0061] In one embodiment, the method includes the step of blow-molding an extruded material (formed from molten pellets of blended materials) to form a blow-molded article. The term "blow molding," as used herein, refers to a process that includes the steps of placing the extruded material in the center of a mold and inflating it with blow pins to press the polymer against the mold walls, and then allowing the product to solidify by cooling. Blow molding can be used to produce hollow plastic containers.

[0062] In one embodiment, the method comprises producing a film from an extruder (an extruder of blended materials), which includes placing a gear pump downstream of the extruder, the gear pump providing high and stable pressure to extrude the extruder through an inflation film die to form a film.

[0063] In one embodiment, the method includes the step of forming a recycled film from a blended material, the recycled film exhibiting less than 33 percent change in the performance of the same physical properties compared to the performance of a film formed from 100% by weight of an olefin-based polymer blend component (which does not contain adhesives, in particular, a solvent-free polyurethane composition). The physical film properties compared between the recycled film and the 100% by weight olefin-based polymer blend component film include tear strength, tensile strength, dirt impact strength, film haze, and combinations thereof. For example, if a 100% by weight olefin-based polymer blend component film has a dirt impact strength of 100 g, the recycled film (formed from the blended material) will have a dirt impact strength of less than 100 g ± 33%, i.e., a dirt impact strength of 67 g to 133 g.

[0064] In one embodiment, the method includes the step of blending pellets of recycled spent material in an amount of 1% to 99% by weight, or 1% to 75% by weight, or 50% by weight, with an olefin polymer blend component (which is a recycled olefin polymer film (the same film as the multilayer film in a multilayer structure, but without the adhesive composition)) to form a blended material. The recycled spent material includes 88% to 99.5% by weight of an ethylene polymer (relative to the total weight of the recycled spent material) and 12% to 0.5% by weight of a solvent-free polyurethane adhesive composition having an aliphatic carbon ratio (ACR) of 6.9 or higher and a Hansen solubility parameter (HSP) of 22.7 or lower. The method includes the step of extruding the blended material to form a recycled film. The recycled film shows less than 33 percent change in the performance of the same physical properties compared to the performance of a film consisting of a recycled olefin polymer multilayer film of the olefin polymer blend component. The physical properties are selected from one, some, or all of the following properties: tear strength, tensile strength, and / or dirt impact strength.

[0065] This disclosure provides articles. In one embodiment, the article is a recycled article and is formed from a blend of an olefin polymer blend component and recycled used material. The recycled used material is formed from a multilayer structure having (i) a layer composed of an olefin polymer and (ii) an adhesive layer composed of a solvent-free polyurethane adhesive composition exhibiting an aliphatic carbon ratio (ACR) value of 6.9 or higher and a Hansen solubility parameter (HSP) value of 22.7 or lower.

[0066] The olefin-based polymer blend components are selected from unused olefin-based polymers, recycled olefin-based polymer multilayer films, and combinations thereof.

[0067] The (recycled) article contains, based on the total weight of the (recycled) article, 1% to 99% by weight, or 1% to 75% by weight, or 50% by weight of recycled used material and 99% to 1% by weight, or 99% to 25% by weight, or 50% by weight of an olefin polymer blend component. The (recycled) article contains, based on the total weight of the (recycled) article, 88% to 99.5% by weight, or 90% to 99.0% by weight, or 95% to 99.0% by weight, or 97% to 99% by weight of ethylene polymers (unused ethylene polymers and non-used ethylene polymers) and 0.5% to 12% by weight, or 1% to 10% by weight, or 1% to 5% by weight, or 1% to 3% by weight of a solvent-free polyurethane adhesive composition.

[0068] In one embodiment, the articles are recycled articles, which include (recycled) pellets, (recycled) single-layer films, (recycled) multi-layer films, (recycled) laminates, (recycled) plastic packaging, (recycled) pipes, (recycled) fibers, (recycled) molded products, and any combination thereof.

[0069] In one embodiment, the (recycled) article is a recycled film. The recycled film contains 1% to 75% or 50% by weight of recycled used material and 99% to 25% or 50% by weight of an olefin polymer blend component, relative to the total weight of the (recycled) article. The (recycled) article contains 88% to 99.5% or 90% to 99.0% by weight of an ethylene polymer, or 95% to 99.0% or 97% to 99% by weight, relative to the total weight of the (recycled) article, and 0.5% to 12% or 1% to 10% by weight, or 1% to 5% or 1% to 3% by weight of a solvent-free polyurethane adhesive composition. The solvent-free polyurethane adhesive composition has an aliphatic carbon ratio (ACR) value of 6.9 or higher and a Hansen solubility parameter (HSP) value of 22.7 or lower. The olefin polymer blend component is a recycled ethylene polymer multilayer film. The recycled film exhibits less than 33 percent change in the performance of the same physical properties compared to a film consisting solely of 100% by weight of olefin-based blend components (recycled ethylene-based polymer multilayer film). The film's physical properties are one, some, or all of the following: tear strength, tensile strength, and / or dirt impact strength.

[0070] Rather than being limiting, some embodiments of this disclosure are described in detail in the following embodiments. [Examples]

[0071] Table 1 below lists the materials used in the comparative sample (CS) and the examples of the present invention (IE).

[0072] [Table 1]

[0073] A. Manufacturing of multilayer films A multilayer olefin polymer film (referred to interchangeably as a 7-layer film) is manufactured on a 7-layer inflation film line (available from Hosokawa-Alpin). The material composition of each of the 7 layers is listed in Table 2. The 7-layer inflation film line utilizes seven extruders with a diameter of 50 mm and an L / D ratio of 30. These extruders feed into a 250 mm diameter spiral mandrel die with a 2 mm die gap, a lay flat of 610 mm, and a gauge of 2 mil (50 pm). The production rate is 148 kg / hour, and the melting temperature is in the range of approximately 185°C to 245°C. A blow-up ratio of 2.5 is used for blowing the 7-layer film, and the 7-layer film is then cooled with single-lip air rings and internal bubble cooling. The line speed is approximately 17 m / min, and the 7-layer film is corona-treated to an average surface energy of >38 dynes / cm.

[0074] Table 2 below provides the structure / composition of a 7-layer film with a thickness of 50 μm.

[0075] [Table 2]

[0076] B. Laminate The laminate is formed by bonding two 7-layer films together, that is, by applying a layer of the solvent-free polyurethane adhesive composition shown in Table 3A to the surface of one 7-layer film, and then positioning the other 7-layer film in contact with the adhesive layer, as described below.

[0077] Table 3A below shows the composition and amount of solvent-free polyurethane adhesive composition applied to the 7-layer film when forming the resulting multilayer structure.

[0078] [Table 3]

[0079] As shown in Table 3A, solvent-free polyurethane adhesive PU A, formed from PACACEL® L75-191 / CR88-141, exhibits both an aliphatic carbon ratio (ACR) value of 6.9 or higher (PU A 14) and a Hansen solubility parameter (HSP) value of 22.7 or lower (PU A 22.5). Solvent-free polyurethane adhesive PU B, formed from MOR-Free® 1390A / MOR-FREE® C33, exhibits an ACR value of 6.9 or higher (PU B 18), but fails to exhibit an HSP value of 22.7 or lower (PU B 25).

[0080] Lamination of multilayer structures is performed using a Labocombi 400 series, a commercially available laminator (available from Nordmeccanica). The Labocombi 400 has a maximum film width of 406 mm and a minimum film width of 254 mm. The laminator includes a solvent-free deck for lamination with solvent-free polyurethane adhesive. The laminator further includes a two-zone forced hot air dryer and a 7.5 kilowatt (KW) corona treatment unit (available from Enercon Industries Corporation) for both primary and secondary films. The maximum line speed of the laminator is 400 meters per minute (m / min) (or 1,312 feet per minute). All unwinds use a 76 mm or 152 mm core, and rewinds use a 76 mm core. Once lamination is complete, the laminate is allowed to fully cure for 7 days at 20 ± 1°C and 50% relative humidity.

[0081] Table 3B below shows the structure / composition for Laminate 1 and Laminate 2. Each has a 7-layer film / PU adhesive layer / 7-layer film structure.

[0082] [Table 4]

[0083] C. Film shredding / pelletization Each of the generated laminates (Laminate 1 and Laminate 2) is then reprocessed by shredding each laminate into a granular form and pelletizing the shredded laminate, resulting in the formation of recyclable spent material. Shredding and pelletizing are achieved using an INTAREMA® 605K pelletizer unit (available from EREMA North America, Inc., 23 Old Right Road-Unit #2, lpswich, MA01938, USA). The pelletizer's barrel zone is operated at 171°C and the pelletizer zone at 176°C. The resulting pellets of recyclable spent material have an average size of 30 pellets per gram.

[0084] Table 4 below shows the composition of recycled used materials.

[0085] [Table 5]

[0086] D. Blending ratio for formulation After pelletization, the pellets of recycled spent material (RPM1 pellets and RNM2 pellets) are blended with the pellets of the olefin polymer blend component in an approximately 50:50 wt% ratio. The olefin polymer blend component (referred herein interchangeably to “control pellets”) is a recycled olefin polymer multilayer film (referred herein interchangeably to “recycled 7-layer film”) obtained by shredding and pelletizing a 7-layer film. Furthermore, this recycled olefin polymer multilayer film differs from the pellets of recycled spent material in that the recycled olefin polymer multilayer film is not laminated and therefore does not contain a solvent-free polyurethane adhesive and is not laminated.

[0087] An inflation film is formed from a blended material having 50% by weight of recycled 7-ply film and 50% by weight of recycled spent material. The production conditions for the inflation film are shown in Table 6A below. Films formed from a blend of 50% by weight of olefin polymer blend component (i.e., recycled 7-ply film) and 50% by weight of recycled spent material are provided for RNM1 and RNM2, respectively. A corresponding control film formed from 100% by weight of recycled 7-ply film is also provided (formed under the production conditions in Table 6A), as shown in Table 6B.

[0088] Table 6A

[0089] [Table 6]

[0090] [Table 7]

[0091] Tables 7A and 7B below show the dirt impact strength, film haze, tear strength, and tensile strength values ​​for Examples IE1 (Table 7A), (including PU A in Table 3A), and IE4 (Table 7B), (including PU B in Table 3A) of the present invention. Tables 7A and 7B also include the mechanical properties for control films CS1 and CS3, which are each formed from 100 wt% recycled 7-ply films. CS1 is prepared from a first batch of recycled 7-ply films. CS2 is prepared from a second batch of recycled 7-ply films several weeks after the preparation of CS1. Tables 7A and 7B also show the change in values ​​(percentage) comparing (i) CS1 vs. IE2 (Table 7A) and (ii) CS3 vs. IE4 (Table 7B).

[0092] [Table 8]

[0093] [Table 9]

[0094] Table 7A shows that film IE2 (recycled film), formed from 50% by weight of recycled 7-ply film and 50% by weight of RNM1 (relative to the total weight of film IE2), shows improvements in dirt impact strength, film haze, tear strength, and tensile strength values ​​compared to film IE4, which is composed of 50% by weight of 7-ply film and 50% by weight of RNM2 (this RNM2 contains PU B) (relative to the total weight of film IE2), when this recycled used material contains PU A.

[0095] Table 7A further shows that film IE2 exhibits less than 33% change in the performance of physical properties such as dirt impact, film haze, tear strength, and tensile strength compared to film CS1 (CS1 consisting of 100% by weight of an olefin-based polymer blend component, which is a recycled 7-layer film). Therefore, Table 7A demonstrates the recyclability of recycled used materials including layers of olefin-based polymers (formed from a laminate having two 7-layer films, all of which are ethylene-based polymers) and layers of solvent-free polyurethane adhesive compositions having both an ACR value of 6.9 or higher and an HSP value of 22.7 or lower.

[0096] In contrast, Table 7B's CS4 (with PU B) demonstrates that recycled used material containing layers of olefin polymers (formed from a laminate with two 7-layer films, all of which are ethylene polymers) and a solvent-free polyurethane adhesive composition (PU B) that does not have both an ACR value of 6.9 or less and an HSP value of 22.7 or more is unrecyclable, as evidenced by a more than 33% change in the performance of physical properties such as dirt impact strength, film haze, tear strength, and tensile strength compared to film CS3 (film CS3 consisting of 100% by weight of an olefin polymer blend component, which is a recycled 7-layer film).

[0097] This disclosure is not limited to the embodiments and examples contained herein, but is specifically intended to include modifications of these embodiments, including some embodiments and combinations of elements of different embodiments, as are included in the following claims.

Claims

1. A step of preparing pellets of recycled used material, wherein the recycled used material is formed from a multilayer structure comprising at least (i) a layer containing an olefin polymer and (ii) an adhesive layer, and the adhesive layer contains a solvent-free polyurethane adhesive composition, The steps include blending the aforementioned pellets with an olefin-based polymer blend component to form a blended material, The steps of forming an article from the blended material and Methods that include...

2. The method according to claim 1, further comprising the step of selecting a solvent-free polyurethane adhesive composition having an aliphatic carbon ratio (ACR) value of 6.9 or higher and a Hansen solubility parameter (HSP) value of 22.7 or lower, prior to the preparation step.

3. The method according to claim 1 or 2, wherein the olefin-based polymer blend component is selected from the group consisting of unused olefin-based polymers, recycled olefin-based polymer multilayer films, and combinations thereof.

4. 99.5% to 88% by weight of ethylene-based polymers, and 0.5% to 12% by weight polyurethane adhesive The method according to any one of claims 1 to 3, comprising the step of preparing pellets of recycled used material containing the above-mentioned material.

5. The process includes the step of blending 1% to 99% by weight of the pellets of the recycled used material with 99% to 1% by weight of the olefin polymer blend component to form the blended material, The method according to any one of claims 1 to 4, wherein the olefin-based polymer blend component is a recycled olefin polymer multilayer film.

6. The method according to any one of claims 1 to 5, wherein the multilayer structure is selected from the group consisting of single-layer films, multilayer films, laminates, plastic packages, molded products, and combinations thereof.

7. The method according to any one of claims 1 to 6, further comprising the step of forming an article selected from the group consisting of pellets, single-layer films, multi-layer films, multi-layer laminates, plastic packages, pipes, fibers, and molded products from the blended material.

8. The article is a film, The method according to claim 7, wherein the film exhibits a change of less than 33 percent in the performance of the same physical properties compared to the performance of a film consisting solely of the olefin-based polymer blend component.

9. The method according to claim 8, wherein the physical properties are selected from the group consisting of tear strength, tensile strength, dirt impact, and combinations thereof.

10. Olefin-based polymer blend components, and (i) a layer containing an olefin polymer and (ii) an adhesive layer, comprising a multilayer structure, wherein the adhesive layer contains a solvent-free polyurethane adhesive composition, Articles that include [this item].

11. The article according to claim 10, wherein the solvent-free polyurethane adhesive composition has an aliphatic carbon ratio (ACR) value of 6.9 or higher and a Hansen solubility parameter (HSP) value of 22.7 or lower.

12. The article according to claim 10 or 11, wherein the olefin polymer blend component is selected from the group consisting of unused olefin polymers, recycled olefin polymer multilayer films, and combinations thereof.

13. 99.5% to 88% by weight of ethylene-based polymers, and 0.5% to 12% by weight polyurethane adhesive An article according to any one of claims 10 to 12, including the article described in any one of claims 10 to 12.

14. An article according to any one of claims 10 to 13, selected from the group consisting of pellets, single-layer films, multi-layer films, multi-layer laminates, plastic packaging materials, pipes, fibers, and molded products.

15. The article according to claim 14, wherein, when the article is a film, the film exhibits a change of less than 33 percent in the performance of the same physical properties compared to the performance of the same physical properties of a film made of the olefin-based blend component.

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