Recyclable laminated structures containing polyolefin dispersions as laminating adhesives - Patents.com

Abstract

Disclosed is a recyclable laminate structure comprising at least one polyolefin substrate layer and a recyclable polyolefin dispersion comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent, and a process for making the same. The recyclable laminate structure is coatable via known coating processes and has improved recyclability properties.

Description

[Technical field]

[0001] The present disclosure relates to a mechanically recyclable laminate structure comprising a polyolefin dispersion, more particularly to a recyclable laminate structure comprising at least one polyolefin substrate layer having a polyolefin dispersion disposed thereon and used as an adhesive layer, the polyolefin dispersion being applied to the surface of the polyolefin substrate via a known application system. The disclosed polyolefin dispersion and the resulting recyclable laminate structure can be used in manufactured articles such as flexible packaging, and have beneficial recyclability properties. [Background technology]

[0002] Polyurethane adhesives are widely used in the packaging industry for flexible packaging, including flexible food packaging. Solvent-based polyurethane adhesives are applied via gravure or flexographic application systems, while solventless systems are applied using a five-roller application system. When flexible packaging is used for food products, adhesive strength and seal resistance are essential.

[0003] Conventional flexible packaging designs are based on laminating functional layers such as polyethylene terephthalate (PET), bi-axially oriented polypropylene (BOPP), metallized PET oriented polypropylene (OPP), aluminum foil, and nylon / polyimide with sealable layers such as low density polyethylene (LDPE) or cast polypropylene (CPP). Conventional flexible packaging is not recyclable because there is no economically practical and technically efficient process for layer separation and recycling of the individual films. Traditionally used lamination adhesives include either acrylic-based adhesives or polyurethane-based adhesives. Combinations of different polyolefin films laminated with such conventional adhesives are difficult to recycle due to the highly crosslinked nature of the adhesives as well as the chemical differences between the lamination adhesives and the polyolefin backbone of the films.

[0004] Therefore, there is a need for an adhesive that allows for a fully recyclable laminate construction with all the beneficial properties mentioned above, namely, good performance and recyclable packaging viability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] Disclosed herein is a fully polyolefin recyclable laminate structure comprising at least one recyclable polyolefin substrate layer and a polyolefin dispersion coatable via a known coating system disposed on at least a portion of the surface of the at least one recyclable polyolefin substrate layer. Also disclosed herein is a mechanically recyclable multi-layer laminate comprising at least two recyclable polyolefin layers laminated together using a polyolefin dispersion coatable via a known coating system.

[0006] Polyolefin backing layer: The disclosed polyolefin substrate layer is made from an olefin-based polymer. The terms "olefin-based polymer", "olefin polymer" and "polyolefin" as used herein refer to a polymer composed mostly of olefin monomers. The term "polymer" refers to a polymeric compound prepared by polymerizing monomers, whether of the same or different types. Thus, the generic term polymer encompasses the term "homopolymer", which is usually used to refer to a polymer prepared from only one type of monomer, as well as "copolymer", which refers to a polymer prepared from two or more different monomers. The polyolefin substrate layer may include a film made from one polyolefin polymer or a film made from a blend of two or more different polyolefin polymers.

[0007] The polyolefin substrate layer may comprise an ethylene-based polymer. As used herein, "polyethylene" or "ethylene-based polymer" refers to a polymer containing more than 50 mole percent of units derived from ethylene monomer. This includes the aforementioned ethylene-based homopolymers or copolymers. Common forms of polyethylene known in the art include, but are not limited to, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), single-site catalyzed linear low density polyethylene (m-LLDPE), including both linear and substantially linear low density resins, medium density polyethylene (MDPE), and high density polyethylene (HDPE). For example, the polyolefin substrate layer may comprise one or more polyolefin layers, such as HDPE, LDPE, LLDPE, MDO PE, BOPE, and mixtures thereof.

[0008] Additionally, as described herein, the term "LDPE" may also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene" and is defined to mean that the polymer is partially or fully homopolymerized or copolymerized in an autoclave or tubular reactor at pressures above 14,500 psi (100 MPa) using a free radical initiator such as peroxide (see, for example, U.S. Pat. No. 4,599,392). LDPE resins typically have a density in the range of 0.916 g / cm to 0.940 g / cm.

[0009] The term "LLDPE", as used herein, can include resins made using Ziegler-Natta catalyst systems, as well as resins made using single-site catalysts, including but not limited to bis-metallocene catalysts (sometimes referred to as "m-LLDPE"), phosphinimine, and constrained geometry catalysts, and post-metallocene molecular catalysts, including but not limited to bis(biphenylphenoxy) catalysts (also referred to as polyaryloxy ether catalysts). LLDPE includes linear, substantially linear, or heterogeneous ethylene-based copolymers or homopolymers. LLDPE contains less long chain branching than LDPE and includes substantially linear ethylene polymers as further defined in U.S. Pat. Nos. 5,272,236, 5,278,272, 5,582,923, and 5,733,155, homogeneously branched ethylene polymers such as those described in U.S. Pat. No. 3,645,992, heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Pat. No. 4,076,698, and blends thereof (such as those disclosed in U.S. Pat. No. 3,914,342 or U.S. Pat. No. 5,854,045). LLDPE resins may be made via gas phase, solution phase, or slurry polymerization, and any combination thereof, using any type of reactor or reactor configuration known in the art. LLDPE resins may be made via gas phase, solution phase, or slurry polymerization, and any combination thereof, using any type of reactor or reactor configuration known in the art.

[0010] Additionally, as used herein, the term "HDPE" generally refers to polyethylene having a density of about 0.940 g / cm or greater that is prepared using a Ziegler-Natta catalyst, a chromium catalyst, or even a metallocene catalyst. The polyolefin substrate layer may be a multilayer film that includes an outer layer that comprises an ethylene-based polymer.

[0011] Suitable polyethylene polymers for use in the present disclosure may be commercially available. Suitable commercially available polyethylene polymers include, but are not limited to, AGILITY™ (e.g., AGILITY™ 1000, AGILITY™ 1001, and AGILITY™ 1021), INNATE™ ST 50, ELITE™ 5940, ELITE™ 5960, DOW™ LDPE 6211, and DOW™ LDPE 7511, all available from The Dow Chemical Company.

[0012] The polyolefin substrate layer used to make the recyclable laminate structures of the present disclosure may comprise a single layer (monolayer) made from one or more polyolefins, olefin polymers, or ethylene vinyl acetate (EVA), or the recyclable laminate structures may comprise a multi-layer structure made from one or more polyolefin layers.

[0013] The polyolefin substrate layer of the present disclosure may be a multilayer film containing more than one layer. As described herein, "multilayer film" refers to any film having multiple layers. For example, a multilayer film may have 2, 3, 4, 5, or more layers. A multilayer film may be described as having layers designated by letters to aid in describing the film. For example, a two-layer film having two different polyolefin film layers may be designated as A / B, and a three-layer film having a core layer B and two outer layers A and C may be designated as A / B / C. Similarly, a structure having two core layers B and C and two outer layers A and D would be designated as A / B / C / D. The polyolefin film may be a coextruded film having an odd number of layers from 3 to 35, such as 3 to 11 or 3 to 7. For example, the polyolefin substrate layer may be a three-layer multilayer film composed of three layers of polyethylene.

[0014] The polyolefin substrate layer may be a multilayer film composed of one or more layers of HDPE, LLDPE, and LDPE, a PP film, a biaxially oriented PP (BOPP) film layer, or a machine-direction oriented PE (MDO PE) or biaxially oriented PE (BOPE) film layer.

[0015] The thickness of the polyolefin substrate layer may be, for example, 12 to 125 μm, 20 to 100 μm, or 25 to 50 μm.

[0016] The polyolefin substrate layer may have a thickness of (≦) 1 mm or less, for example, ≦900 μm, ≦800 μm, ≦700 μm, ≦600 μm, ≦500 μm, ≦400 μm, ≦300 μm, or even ≦200 μm. The polyolefin substrate layer may have a thickness of (≧) 1 μm or more, ≧5 μm, ≧10 μm, ≧20 μm, ≧30 μm, ≧40 μm, or even ≧50 μm. As will be understood by those skilled in the art, in a multilayer film, the thicknesses of different layers may be the same or different, and the thicknesses of the layers may be selected by techniques known to those skilled in the art based on the disclosure herein.

[0017] The polyolefin substrate layer can be made of a low density polymer. The polyolefin substrate layer can be a polyethylene / polyethylene film or a polypropylene / polypropylene film. The polyolefin substrate layer can be blown or coextruded.

[0018] Polyolefin Dispersions: The recyclable laminate structure disclosed herein can include an aqueous polyolefin dispersion. The polyolefin dispersion can include a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent. The polyolefin-based polymer can be a low melting point polyolefin-based polymer. The polyolefin-based polymer can have a viscosity of 0.80 (g / cm 3For example, polyolefin-based polymers including polyolefins can have a density of 0.80 to 1.1 g / cm 3 , 0.89~1.0g / cm 3 , 0.90g / cm 3 , or 0.91 to 0.97 g / cm 3 The density can range from 0.01 to 0.01.

[0019] The polyolefin-based polymer may include polypropylene and / or polyethylene, such as high density polyethylene, medium density polyethylene, low density polyethylene, or combinations thereof. As used herein, high density polyethylene has a molecular weight of 0.93 to 0.97 grams per cubic centimeter (g / cm 3 It refers to polyethylene with a density in the range of 0.93 to 0.97 g / cm 3 All individual values ​​and subranges are included and disclosed herein. As used herein, medium density polyethylene refers to polyethylene having a lower density than high density polyethylene. As used herein, low density polyethylene refers to polyethylene having a lower density than medium density polyethylene.

[0020] The polyolefin-based polymer may comprise homopolymers and / or copolymers, including elastomers of polyolefins, such as polyethylene and / or polypropylene polymers. The polyolefin-based polymer may comprise ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-t-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, 1-dodecene, polyethylene, polypropylene, poly-1-butene, poly-3-methyl-1-butene, poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, ethylene-propylene copolymers, ethylene-butadiene, ethylene-ethylidene norbornene copolymers, ethylene-propylene-butadiene copolymers, ethylene-propylene ... Dicyclopentadiene copolymers, ethylene-propylene-1,5 hexadiene copolymers, ethylene-propylene-ethylidene norbornene copolymers; ethylene-vinyl acetate copolymers, ethylene-vinyl ethylene-vinyl alcohol copolymers, ethylene-vinyl chloride copolymers, ethylene acrylic acid or ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylate copolymers, as well as ethylene butene (ENGAGE™ 7447) and very low density ethylene-octene (ENGAGE™ 8842).

[0021] The polyolefin-based polymers can include functionalized polyolefins based on polypropylene or polyethylene homopolymers or copolymers, where the polymers are modified with hydroxyl, amine, aldehyde, epoxide, ethoxylate, carboxylic acid, ester, anhydride groups, or combinations thereof. The polyolefin may comprise an unfunctionalized polyolefin such as commercially available high density polyethylene, including, but not limited to, DMDA-8007 NT 7 (melt index 10, density 0.943), DMDA-1210 NT 7 (melt index 10, density 0.952), HDPE 17450N (melt index 17, density 0.950), DMDA-8920 NT 7 (melt index 20, density 0.954), DMDA 8940NT 7 (melt index 44, density 0.951), DMDA-8950 NT 7 (melt index 50, density 0.942), and DMDA-8965-NT 7 (melt index 66, density 0.952), all available from The Dow Chemical Company. Other examples of suitable polyolefin-based polymers are propylene-ethylene alternating copolymers, and propylene-ethylene diblock copolymers, and propylene-ethylene alternating copolymers, all available from Dow Chemical Company.

[0022] The polyolefin may have different molecular weights for different applications. For example, the polyolefin may have a molecular weight of more than 800 grams / mole, such as more than 5000 grams / mole, or more than 50,000 grams / mole. The polyolefin may have a crystalline melting point of less than 45°C or less than 50°C.

[0023] The polyolefin may be a propylene-alpha olefin copolymer, such as a propylene-ethylene or propylene-ethylene-butene copolymer or interpolymer. The polyolefin may be a propylene / alpha-olefin copolymer characterized as having substantially isotactic propylene sequences. "Substantially isotactic propylene sequences" refers to sequences that are13 It means having an isotactic triad (mm) greater than 0.85, in another alternative greater than 0.90, in another alternative greater than 0.92, and in another alternative greater than 0.93, as measured by C NMR. Isotactic triads are well known in the art and are described in U.S. Pat. No. 5,504,172 and WO 00 / 01745.

[0024] The olefin-based polymer may contain units derived from propylene and polymer units derived from one or more alpha-olefin comonomers. Examples of comonomers that may be utilized in the preparation of the base polymer include C 2 and C 4 ~C 10 Alpha-olefins, e.g., C 2 , C 4 , C 6 , and C 8 is an alpha-olefin. The base polymer can include 1 to 40 weight percent of units derived from one or more alpha-olefin comonomers. All individual values ​​and subranges from 1 to 40 weight percent are included herein and disclosed herein. The polyolefin-based polymer can be characterized as including 60 to 100, 80 to 99, or 85 to 99 weight percent of units derived from polyethylene and greater than 0 to 40, 1 to 20, 4 to 16, or 4 to 15 weight percent of units derived from at least one other polyolefin.

[0025] The polyolefin-based polymer can be characterized as comprising 60 to 100, 80 to 99, or 85 to 99 weight percent of units derived from polypropylene and greater than 0 to 40, 1 to 20, or 4 to 15 weight percent of units derived from at least one other polyolefin.

[0026] The polar component may be a stabilizer. The polar component may be a polar polyolefin. The polar component may be selected from the group including, but not limited to, ethylene-acrylic acid and ethylene-methacrylic acid copolymers such as PRIMACOR™ 5980 and NUCREL™ 960. The polar component may also be selected from the group including, but not limited to, ethylene ethyl acrylate copolymers, ethylene methyl methacrylate, ethylene butyl acrylate, and combinations thereof. Other ethylene-carboxylic acid copolymers may be used.

[0027] The polar component can include a functionalized polyolefin, for example, a homopolymer or copolymer of polypropylene or polyethylene, where the polymer has been modified with hydroxyl, amine, aldehyde, epoxide, ethoxylate, carboxylic acid, ester, anhydride groups, or combinations thereof.

[0028] The polyolefin dispersion can include a neutralizing agent such that the polyolefin-based laminating adhesive has a pH of 8 to 11. All individual values ​​and subranges between 8 and 11 are included herein and disclosed herein. For example, the polyolefin dispersion can have a pH from a lower limit of 8, 8.1, 8.2, or 8.3 to an upper limit of 11, 10.9, 10.8, or 10.7. For example, the aqueous dispersion can have a pH of 8 to 11, 8.1 to 10.9, 8.2 to 10.8, or 8.3 to 10.7.

[0029] The neutralizing agent may have a boiling point of less than 140° C. Examples of suitable neutralizing agents include, but are not limited to, hydroxides, carbonates, bicarbonates, amines, and combinations thereof. Examples of suitable hydroxides include, but are not limited to, ammonium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydroxide, and combinations thereof. Examples of suitable carbonates include, but are not limited to, sodium carbonate, sodium bicarbonate, potassium carbonate, calcium carbonate, and combinations thereof. Examples of suitable amines include, but are not limited to, monoethanolamine, diethanolamine, triethanolamine, ammonia, monomethylamine, dimethylamine, trimethylamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, diisopropanolamine, N,N-dimethylethanolamine, mono-n-propylamine, dimethyl-n-propylamine, N-methanolamine, N-aminoethylethanolamine, and amines such as morpholine, piperazine, piperidine, and combinations thereof.

[0030] The polyolefin dispersion may have an active product concentration of less than 55% by weight. The polyolefin dispersion may have a water content of greater than 45% by weight, based on the total weight of the polyolefin dispersion.

[0031] Laminate formation: A recyclable laminate structure with improved recyclability properties can be produced by coating a recyclable polyolefin substrate layer with a polyolefin-based dispersion composition comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent. The produced recyclable laminate structure should have recyclability properties with less than 50 percent performance change compared to a substrate layer that does not contain the polyolefin-based dispersion composition. The "recyclability" properties of the laminate structure of the present invention can be measured, for example, by the laminate properties including (1) mechanical properties (e.g., tensile modulus) and (2) IR absorption properties of the laminate by comparing these properties with those of conventional laminate structures. To further determine the recyclability of the laminate film structure, other properties such as transparency and gel content of the film present in the multi-layer laminate structure of recycled materials can be measured as necessary.

[0032] A monolithic material with improved recyclability properties can be produced by applying a polyolefin dispersion composition comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent to a first recyclable polyolefin substrate layer. A second recyclable polyolefin substrate layer is then laminated to the first recyclable polyolefin substrate layer. The produced monolithic material should have recyclability properties with less than 50 percent change in performance compared to a mechanically recyclable monolithic material without a coating layer. A known application system for applying the polyolefin dispersion can be a gravure process. A known application process for applying the polyolefin dispersion can be a flexographic, semi-flexographic, or rotogravure process. The polyolefin dispersion can be applied with a laminator using a rotogravure cylinder. During application of the polyolefin dispersion, the coating weight can be between 2 and 4 g / m2. 2(dry). The polyolefin dispersion is allowed to dry completely in a drying tunnel. The first substrate layer, coated with the polyolefin dispersion and dried, may be nipped to the second substrate layer in a calander. During lamination, the uncoated side of the first substrate layer may be in contact with a metal cylinder. During lamination, the second substrate layer may be in contact with a rubber roller. During lamination, the metal cylinder may be heated to a temperature of 90° C. or higher. During lamination, the adhesive may reach a temperature of 40° C. During lamination, the adhesive may reach a temperature of 50° C. During lamination, the adhesive may reach a temperature slightly higher than the first melting point peak of the adhesive. During lamination, the laminator may run at a speed of 10 m / min. During lamination, the laminator may run at 50 m / min. After lamination, the multi-layer laminate may be stored at 60° C. for 24 hours.

[0033] Without being bound by theory, it is believed that the ionic content and hardness of the base used may be the cause of failure of the present disclosure. It is believed that this results in a polar adhesive that cannot hold two non-polar substrate layers together. It is believed that drying counters this, so if a base with a high ionic content is used, if a high lamination speed is used, or if the metal cylinder is heated to a lower temperature during lamination, post-lamination heating may be required to reach the desired bond strength.

[0034] Laminates made using the present disclosure may have a bond strength of 1.7-3N / 15mm. Laminates made using the present disclosure may have a bond strength of 2-3N / 15mm. Laminates made using the present disclosure may have a bond strength of 2-2.5N / 15mm.

[0035] The recyclable laminated structures of the present disclosure can be used in packaging applications, for example, to produce various packaging materials and products. For example, the recyclable laminated structures can be used in bulk packaging of food grains / legumes, seed packaging, lentil and grain packaging, fertilizer packaging, oilseed packaging, sugar packaging, salt packaging, pharmaceutical packaging, packaging of other food products, and personal care articles such as bath salts, detergent pods, etc. The recyclable laminated structures can also be used as wrappers for baby wipes, feminine hygiene products, cereal bars, protein bars, cheese, and confectionery products. Furthermore, other advantageous features and applications of the recyclable substrate layer when used to package articles include, for example, resistance to harsh weather conditions, high tensile strength, robust drop test resistance, excellent optical appearance, and resistance to leakage. EXAMPLES

[0036] [Table 1]

[0037] [Table 2]

[0038] Preparation of Dispersions: Examples 1-8 Aqueous Dispersions 1-8 having the compositions disclosed in Table 2 above are formed from the ingredients disclosed in Table 1 above, using the conditions set forth in Table 2 above, and prepared using the following general procedure.

[0039] Components 1 and 2, listed in Table 2 above, are fed into a 25 mm diameter twin screw extruder using a controlled speed feeder with feed rates in grams per minute (g / min) as shown in Table 2 above. Components 1 and 2 are passed through the extruder and melted to form a liquid molten material. Component 3, if present, is either pumped into the melt as a liquid (oleic acid) or added to the extruder using a controlled speed feeder (SURLYN PC 2000).

[0040] The temperature profile of the extruder is increased to the temperatures listed in the "Polymer Melt Zone" column of Table 2 above. Water and a 30 wt% aqueous solution of potassium hydroxide (abbreviated KOH), dimethylethanolamine (abbreviated DEMA), or 29 wt% aqueous ammonia (abbreviated NH 4 The mixture is mixed with a neutralizing base agent, either 0.1% or 1.0% ethanol (OH), and fed into the extruder at the initial water introduction point at the rate shown in Table 2. Dilution water is then fed into the extruder at the rate shown in Table 2. The extruder speed (rpm) used is also recorded in Table 2. At the extruder exit, a back pressure regulator is used to adjust the pressure in the extruder barrel to a suitable pressure to reduce steam formation (typically, the pressure was 2 MPa to 4 MPa).

[0041] Each aqueous dispersion exits the extruder and is first filtered through a 200 micrometer (μm) filter. The resulting filtered aqueous dispersion has a solids content measured in weight percent (wt%) and the solid particles of the dispersion have a volume average particle size measured in micrometers. The solids content of the aqueous dispersion is measured using an infrared solids analyzer and the particle size of the solid particles of the aqueous dispersion is measured using a COULTER™ LS-230 particle size analyzer (Beckman Coulter Corporation, Fullerton, CA). The solids content and average particle size (PS) of the solid particles of the dispersion are shown in Table 2 above.

[0042] Each polyolefin dispersion is applied to the respective substrate by rotogravure lamination using a LABO COMBI™ 400 laminator available from Nordeccanica Group. The polyolefin dispersion is first coated onto the first substrate layer (MDO-PE for all samples listed in Table 3), the water is completely evaporated in a drying tunnel, and the first substrate layer is nipped to the second substrate layer (PE 1-09 for the laminated samples considered in this invention). The coating weight during this process is kept within the range of 2-4 g / m2. 2Keep dry. During the nipping process, a metal cylinder heated to 90°C contacts the uncoated side of the primary substrate layer, and a rubber roller contacts the uncoated second substrate. The resulting laminate structure is then rolled up.

[0043] The polyolefin substrates used to make laminates containing dispersions from the inventive and comparative examples are summarized in Table 3.

[0044] [Table 3]

[0045] The bond strength of the laminates made starting from the Illustrative Example (IE) and Comparative Example (CE) are tested with an Instron tensile tester equipped with a 50N load cell. 15 millimeter strips are tested at a speed of 100 mm / min. Three strips are tested for each laminate, and the high and average strengths are recorded along with the failure mode. In case of substrate layer tear and elongation, the high value is reported, and for other failure modes, the average T-peel bond strength is reported. The bond strength is tracked immediately after application (green tack), after 1 day, and after 7 days. The lamination speed for all examples is 10 m / min. The results of the laminate structures from both the inventive examples and the comparative examples are shown in Table 43.

[0046] Comparative Example 1 in Table 43 is HYPOD™ 1000 aqueous acid-modified polyolefin dispersion available from DOW™. Comparative Example 2 is ADCOTE™ 37 JD 1198 BW, a water-based dispersion composed of high molecular weight ethylene interpolymer.

[0047] [Table 4] COI = cohesive failure a MDO = AF MDO Adhesive failure with adhesive remaining on the PE film surface a PE=AF Adhesive failure with adhesive remaining on the unstretched PE layer (sealing film)

[0048] [Table 5]

[0049] As shown in Table 5, an application temperature during lamination of 54°C in the calendering process reaches an adhesion value of about 2N / 15mm, while little adhesion occurs between the MDO PE and PE layers when a temperature of only 38°C is reached. However, when a laminate made at 38°C in the calendering process is stored at 60°C for 24 hours, a bond strength comparable to that of the sample with an application temperature of 54°C can be achieved.

[0050] To reach a bond strength of 2N / 15mm or more, the temperature at which the dry polyolefin layer applied on the first substrate layer is calendered against the secondary substrate layer must be slightly higher than the first melting point of the adhesive.

[0051] Recyclability rating: Two PE films (PE films for recyclability testing) are prepared and laminated with the PE-based adhesive disclosed above (IE6). The laminated material is crushed into 10-20 mm flakes and dried in ambient air for 24 hours. The non-laminated PE film is crushed similarly. Both sets of crushed samples are then extruded at a temperature of 250°C. A blend consisting of 50% non-laminated PE film and 50% virgin LDPE (B0) is prepared along with a blend consisting of 50% virgin LDPE and 50% PE material laminated with the disclosed adhesive (B100). Both blends are used to make blown films with melt temperatures of 200-230°C, thickness <25μm, and blow-up ratio >2.5. The recyclability evaluation results are shown in Table 4 below.

[0052] [Table 6]

[0053]

Table 7

Claims

1. A recyclable laminate structure having improved recyclability properties, comprising: a. at least one polyolefin substrate layer comprising a recyclable polyolefin; b. a recyclable polyolefin-based dispersion composition that can be applied via known application systems, comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent; A recyclable laminated structure comprising:

2. A mechanically recyclable multi-layer laminate comprising: a. a first substrate layer comprising a recyclable polyolefin; b. a polyolefin-based dispersion composition that can be applied to the first recyclable polyolefin substrate layer via known coating systems; wherein the first recyclable polyolefin substrate layer is laminated to a second recyclable polyolefin substrate layer by a recyclable polyolefin-based dispersion composition, applyable via known application systems, comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent to form a mechanically recyclable multi-layer laminate.

3. The mechanically recyclable multi-layer laminate of claim 2 or the recyclable laminate structure of claim 1, wherein the known application system is a gravure process.

4. 10. A recycled article made from either the recyclable laminate structure of claim 1 or the mechanically recyclable multi-layer laminate of claim 2.

5. 10. A packaging article made from either the recyclable laminate structure of claim 1 or the mechanically recyclable multi-layer laminate of claim 2.

6. 3. The recyclable laminate structure of claim 1 or the mechanically recyclable multi-layer laminate of claim 2, wherein the substrate layer is dried after lamination and before use.

7. 1. A process for making a recyclable laminate structure having improved recyclability properties, comprising: a. providing at least one recyclable polyolefin substrate layer; b. applying a polyolefin-based dispersion composition comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent to said at least one recyclable polyolefin substrate layer via a known application system to form a recyclable laminate structure having improved recyclability properties; The process includes:

8. 1. A process for making a single material having improved recyclability characteristics, comprising: a. providing a first recyclable polyolefin substrate layer; b. providing a second recyclable polyolefin substrate layer; c. applying a polyolefin dispersion composition to the first recyclable polyolefin substrate layer, the polyolefin dispersion composition comprising a polyolefin-based polymer, a polar component present as a salt, and a neutralizing agent; wherein the first recyclable polyolefin substrate layer is laminated to the second recyclable polyolefin substrate layer to form a single material having improved recyclability properties.

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