Recyclable and compostable adhesive

Abstract

Laminates are disclosed that are produced using a solventless laminating adhesive comprising an isocyanate and a polyol component and have a recyclability characteristic of 25%. The isocyanate component can comprise 50-70% by weight of an aromatic isocyanate. The isocyanate component can comprise 0-50% by weight of a polyether polyol. The isocyanate component can comprise 0-7% by weight of a natural oil polyol. The isocyanate component can comprise 50-70% by weight of an aromatic isocyanate, 0-50% by weight of a polyether polyol, and 0-7% by weight of a natural oil polyol. The polyol component can comprise a natural oil polyol. Laminates are disclosed that are produced using a solventless laminating adhesive comprising an isocyanate component and a polyol component, and that decompose during composting such that (1) plastic residues are not readily distinguishable from other organic materials, (2) polymer molecules are chemically converted to biomass and other products, (3) the resulting compost allows for proper plant growth, and (4) the resulting compost eliminates high levels of metals. The isocyanate component can comprise 50-70% by weight of an aromatic isocyanate. The isocyanate component can comprise 0-50% by weight of a polyether polyol. The isocyanate component can comprise 0-7% by weight of a natural oil polyol. The isocyanate component can comprise 50-70% by weight of an aromatic isocyanate, 0-50% by weight of a polyether polyol, and 0-7% by weight of a natural oil polyol. The polyol component can comprise a natural oil polyol.

Description

[Technical Field]

[0001] The present disclosure relates to adhesives. More particularly, the present disclosure relates to solventless adhesives. Even more particularly, the present disclosure relates to solventless adhesives that are recyclable and compostable.

[0002] (Introduction) Adhesive compositions are useful for a wide variety of purposes. For example, some adhesives are used to bond two or more film layers of a substrate together, thereby forming a composite film, i.e., a laminate containing two or more film layers. Examples of substrates typically include polyethylene, polypropylene, polyester, polyamide, metal, paper, or cellophane. The use of adhesives in various lamination end uses is generally known. For example, adhesives are generally applied between laminate films and can be used in the production of film / film and film / foil laminates used in the flexible packaging industry for packaging food, pharmaceuticals, and industrial consumables, particularly food packaging. Laminating adhesives can generally be classified into three categories: (1) solvent-based laminating adhesives, (2) solventless laminating adhesives, and (3) water-based laminating adhesives. Adhesive performance varies depending on the category and the application to which the adhesive is applied.

[0003] There are many types within the category of solventless laminating adhesives, and one particular type is multi-component laminating adhesives, more specifically, two-component adhesives. Typically, two-component laminating adhesives include a first component containing an isocyanate and / or a prepolymer and a second component containing one or more polyols. The prepolymer can be obtained by reacting a polyisocyanate with a polyether polyol and / or a polyester polyol. The second component includes a polyether polyol and / or a polyester polyol. Each component may optionally include one or more additives.

[0004] The two components of the adhesive composition (i.e., the isocyanate component and the polyol component) are combined in a predetermined ratio, thereby forming the adhesive composition. The adhesive composition is then applied onto a film / foil substrate. Another film / foil substrate is then contacted with the other substrate to form a curable laminate structure. The laminate structure is cured to bond the two substrates together.

[0005] Solvent-free adhesives are generally more environmentally friendly because they do not contain potentially polluting organic solvents, but they are typically not recyclable or compostable. While single-substrate solutions such as 100% polyethylene adhesives may work in some cases, they are not suitable for all situations. This is especially true as composting of laminates becomes more common, and recyclable adhesives are not necessarily compostable. Therefore, there is a need for adhesives that are both recyclable and compostable. Summary of the Invention

[0006] Laminates are disclosed that are manufactured using a solventless laminating adhesive comprising an isocyanate and a polyol component and that has a recyclability characteristic of 25%. The isocyanate component can comprise 50-70 wt% aromatic isocyanate, based on the weight of the isocyanate component. The isocyanate component can comprise 0-50 wt% polyether polyol, based on the weight of the isocyanate component. The isocyanate component can comprise 0-7 wt% natural oil polyol, based on the weight of the isocyanate component. The isocyanate component can comprise 50-70 wt% aromatic isocyanate, 0-50 wt% polyether polyol, and 0-7 wt% natural oil polyol, based on the weight of the isocyanate component. The polyol component can comprise a natural oil polyol.

[0007] Laminates are disclosed that are produced using a solventless laminating adhesive comprising an isocyanate component and a polyol component, and that decompose during composting such that (1) plastic residues are not readily distinguishable from other organic materials, (2) polymer molecules are chemically converted to biomass and other products, (3) the resulting compost allows for proper plant growth, and (4) the resulting compost eliminates high levels of metals. The isocyanate component may comprise 50-70 wt.% aromatic isocyanate, based on the weight of the isocyanate component. The isocyanate component may comprise 0-50 wt.% polyether polyol, based on the weight of the isocyanate component. The isocyanate component may comprise 0-7 wt.% natural oil polyol, based on the weight of the isocyanate component. The isocyanate component may comprise 50-70 wt.% aromatic isocyanate, 0-50 wt.% polyether polyol, and 0-7 wt.% natural oil polyol, based on the weight of the isocyanate component. The polyol component may include a natural oil polyol. DETAILED DESCRIPTION OF THE INVENTION

[0008] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether specifically disclosed or not. For the avoidance of doubt, all compositions claimed through the use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless otherwise stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any succeeding description any other component, step, or procedure, except those that are not essential to operability. The term "consisting of" excludes any component, step, or procedure not specifically delineated or listed. The term "or" refers to the listed members individually and in any combination, unless otherwise stated. The use of the singular includes the use of the plural, and vice versa.

[0009] Numerical ranges disclosed herein include all values ​​between and including the lower and upper limits. Ranges containing explicit values ​​(e.g., a range of 1, or 2, or 3-5, or 6, or 7) include any subranges between any two explicit values ​​(e.g., the range 1-7 above includes subranges 1-2, 2-6, 5-7, 3-7, 5-6, etc.).

[0010] The term "composition" refers to a mixture of materials that comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0011] An "isocyanate" is a chemical substance containing at least one isocyanate group in its structure. An isocyanate group is represented by the formula: -N=C=O, or abbreviated "NCO." An isocyanate containing more than one, or at least two, isocyanate groups is a "polyisocyanate." An isocyanate with two isocyanate groups is a diisocyanate, an isocyanate with three isocyanate groups is a triisocyanate, and so on.

[0012] A "polyisocyanate" is a molecule that contains at least two isocyanate groups.

[0013] As used herein, 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 (used to refer to a polymer prepared from only one type of monomer), and the terms copolymer or interpolymer. Minor impurities (e.g., catalyst residues) may be incorporated into and / or present within the polymer. The polymer may be a single polymer, a polymer blend, or a polymer mixture, including a mixture of polymers formed in situ during polymerization.

[0014] As used herein, the term "copolymer" means any polymer having two or more monomers.

[0015] A "polyol" is an organic compound containing multiple hydroxyl (OH) groups. In other words, a polyol contains at least two OH groups. Non-limiting examples of suitable polyols include diols, which have two OH groups, triols, which have three OH groups, and tetraols, which have four OH groups.

[0016] As used herein, the term "polyethylene" means a polymer containing a majority (>50 mol%) of units derived from ethylene monomers.

[0017] A "polyether" is a compound containing two or more ether linking groups in the same linear chain of atoms.

[0018] A "polyester" is a compound containing two or more ester linking groups in the same linear chain of atoms.

[0019] A "polyester polyol" is a compound that contains a polyester and a polyol within the backbone structure of the compound.

[0020] A "polyether polyol" is a compound that contains a polyether and a polyol within the compound's backbone structure.

[0021] "Recyclable" or "recyclability" herein means mechanically recyclable or recyclable, meaning that the film article having the waterborne olefin-based coating can be mechanically reprocessed to create another subsequent recycled article having the desired performance and desired properties.

[0022] As used herein, "recyclability" is a measure of the change in performance between a second article made from recycled materials from a first article and a third article made from non-recycled materials. For example, if the performance of an article made from recycled materials is reduced by 50% in tear, gloss, haze, and other properties when compared to an article made from non-recycled materials, the recyclability property is 50%.

[0023] As used herein, "composting" means the transformation of material into a soil-like material, with or without human intervention.

[0024] As used herein, "compostable" means that the material is susceptible to composting.

[0025] As used herein, "biomass" means organic material.

[0026] Laminates manufactured using solventless laminating adhesives Laminates made using solventless laminating adhesives are disclosed. The solventless laminating adhesives can have an isocyanate component and a polyol component. The laminates can have a recyclability characteristic of 25% or less. The laminates can have a recyclability characteristic of 0-25%. All individual values ​​and subranges are disclosed. For example, the polymers can have a recyclability characteristic from a lower limit of 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, or 22% to an upper limit of 25, 23, 21, 19, 17, 15, 13, 11, 9, 7, 5, or 3%. The laminates are compostable. The laminates are capable of decomposing so that plastic residues are not readily distinguishable from other organic materials. The laminates are capable of decomposing so that at least 50% of the laminate is plastic residues that are not readily distinguishable from other organic materials. The laminate may decompose such that 50-100% of the laminate is a plastic residue that is not readily distinguishable from other organic materials. All individual values ​​and subranges are disclosed. For example, the laminate may decompose from an upper limit of 100, 95, 90, 85, 80, 75, 70, 65, 60, or 55% to a lower limit of 55, 60, 65, 70, 75, 80, 85, 90, or 95% of the laminate.

[0027] The laminate may degrade such that the polymer molecules are chemically converted to biomass and other products. The laminate may degrade such that the polymer molecules are chemically converted to biomass and other products when compared to a reference material. The laminate may degrade such that at least 50% of the laminate is chemically converted to biomass and other products when compared to a reference material. The laminate may degrade such that 50-100% of the laminate is chemically converted to biomass and other products when compared to a reference material. All individual values ​​and subranges are disclosed. For example, the laminate may degrade such that from an upper limit of 100, 95, 90, 85, 80, 75, 70, 65, 60, or 55% to a lower limit of 55, 60, 65, 70, 75, 80, 85, 90, or 95% of the laminate is chemically converted to biomass and other products when compared to a reference material.

[0028] The laminate may decompose such that the resulting compost allows for proper plant growth. The laminate may decompose such that plants will germinate in the presence of the decomposed laminate. The laminate may decompose such that plants will germinate in the presence of soil containing at least 10% decomposed laminate. The laminate may decompose such that plants will germinate in the presence of soil containing 10-90% decomposed laminate. All internal values ​​and subranges are disclosed. For example, the laminate may decompose such that plants will germinate in the presence of soil containing from an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% decomposed laminate to a lower limit of 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% decomposed laminate.

[0029] The laminate may degrade such that at least 1% of the seeds germinate in the presence of the degraded laminate. The laminate may degrade such that 1-90% of the seeds germinate in the degraded laminate. All internal values ​​and subranges are disclosed. For example, the laminate may degrade such that an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5% of the seeds germinate in the degraded laminate, to a lower limit of 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% of the seeds germinate in the degraded laminate.

[0030] The laminate is degradable such that at least 1% of seeds will germinate in the presence of soil containing at least 10% degraded laminate. The laminate is degradable such that 1% to 90% of seeds will germinate in the presence of soil containing 10-90% degraded laminate. All intervals and subranges within both ranges are disclosed. For example, the laminate may decompose such that from an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, or 1% to a lower limit of 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% of the seeds will germinate in soil containing from an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% to a lower limit of 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% of the seeds.

[0031] The laminate may degrade such that at least 1% of seeds germinate in the presence of the degraded laminate when compared to a blank. The laminate may degrade such that 1-90% of seeds germinate in the degraded laminate when compared to a blank. All internal values ​​and subranges are disclosed. For example, the laminate may degrade such that an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5% to a lower limit of 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% of seeds germinate in the degraded laminate when compared to a blank.

[0032] The laminate is capable of degrading such that at least 1% of seeds germinate in the presence of soil containing at least 10% degraded laminate when compared to a blank. The laminate is capable of degrading such that 1% to 90% of seeds germinate in the presence of soil containing 10-90% degraded laminate when compared to a blank. All values ​​and subranges within both ranges are disclosed. For example, the laminate may degrade such that from an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, or 1% to a lower limit of 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% of the seeds germinate in soil containing from an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% to a lower limit of 10, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% of the seeds when compared to a blank.

[0033] The laminate may decompose such that a plant grown in the presence of the decomposed laminate produces at least 95% of the biomass of the blank. The laminate may decompose such that a plant grown in the presence of the decomposed laminate produces 1-95% of the biomass of the blank. All internal values ​​and subranges are disclosed. For example, the laminate may decompose such that a plant grown in the presence of soil produces at least from an upper limit of 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or 5% of the biomass of the blank to a lower limit of 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90% of the biomass of the blank.

[0034] The laminate may decompose such that plants grown in the presence of the decomposed laminate produce at least 95% biomass relative to the blank in soil containing at least 10% decomposed laminate. All internal values ​​and subranges are disclosed. For example, the ... from an upper limit of 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% to a lower limit of 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85% decomposed laminate. , can be decomposed to produce at least 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 10, or 5% upper limit to 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90% lower limit of biomass relative to the blank.

[0035] The laminate may decompose such that the resulting compost eliminates high levels of metals. The laminate may decompose such that the resulting compost eliminates high levels of cadmium, chromium, copper, lead, nickel, zinc, mercury, and arsenic. The laminate may decompose such that the resulting compost has less than 0.74 mg / kg cadmium on a dry basis. The laminate may decompose such that the resulting compost has less than 10.24 mg / kg chromium on a dry basis. The laminate may decompose such that the resulting compost has less than 13.84 mg / kg copper on a dry basis. The laminate may decompose such that the resulting compost has less than 9.41 mg / kg lead on a dry basis. The laminate may decompose such that the resulting compost has less than 5.45 mg / kg nickel on a dry basis. The laminate may decompose such that the resulting compost has less than 23.43 mg / kg zinc on a dry basis. The laminate may decompose such that the resulting compost has less than 0.08 mg / kg mercury on a dry basis. The laminate is capable of decomposing such that the resulting compost has less than 0.13 mg / kg arsenic on a dry basis.

[0036] The laminate can decompose during composting such that (1) plastic residues cannot be easily distinguished from other organic materials, (2) polymer molecules are chemically converted into biomass and other products, (3) the resulting compost allows for proper plant growth, and (4) the resulting compost eliminates high levels of metals.

[0037] The polyol component may comprise 60 to 90% by weight of the laminating adhesive, including all individual values ​​and subranges. The polyol component may, for example, comprise 65 to 85% by weight of the laminating adhesive.

[0038] Isocyanate component The isocyanate component may contain 50 to 70 weight percent aromatic isocyanate, based on the weight of the isocyanate component. All internal values ​​and subranges are included. For example, the isocyanate component may contain 55 to 65 weight percent aromatic isocyanate or 60 to 70 weight percent aromatic isocyanate, based on the weight of the isocyanate component. The aromatic isocyanate in the isocyanate component may be, for example, an isocyanate monomer, a polyisocyanate (e.g., a dimer, a trimer, etc.), an isocyanate prepolymer, or a mixture of two or more thereof. A "polyisocyanate" is any compound containing two or more isocyanate groups.

[0039] Aromatic isocyanates useful in the present disclosure can include, for example, one or more polyisocyanate compounds, including, but not limited to, 1,3- and 1,4-phenylene diisocyanate, 1,5-naphthylene diisocyanate, 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 4,4′-diphenylmethane diisocyanate (4,4′-MDI), 3,3′-dimethyl-4,4′-biphenyl diisocyanate (TODI) and its isomers, polymeric isocyanates, and mixtures of two or more thereof.

[0040] Some examples of commercially available aromatic components useful in the present disclosure may include, but are not limited to, ISONATE™ 125M, ADCOTTE™ L76-204, COREACTANTCT™ available from The Dow Chemical Company; DESMODUR™ E 2200 / 76 available from The Covestro Company; and mixtures thereof.

[0041] The aromatic isocyanate can be at least 50% 4-4'-diphenylmethane diisocyanate. The aromatic isocyanate can be at least 90% 4-4'-diphenylmethane diisocyanate. The aromatic isocyanate can be 50-100% 4-4'-diphenylmethane diisocyanate. All internal values ​​and subranges are disclosed. For example, the aromatic isocyanate can be at least 55-95% 4-4'-diphenylmethane diisocyanate.

[0042] The isocyanate component may comprise 0 to 50 weight percent polyether polyol, based on the weight of the isocyanate component. All internal values ​​and subranges are disclosed. For example, the isocyanate component may comprise 5 to 40 weight percent or 10 to 35 weight percent polyether polyol, based on the weight of the isocyanate component. Suitable polyether polyols include, but are not limited to, polypropylene glycol, polytetramethylene ether glycol, polybutylene oxide-based polyols, or mixtures and copolymers thereof. Commercially available polyester polyols that can be used in the present disclosure include, but are not limited to, Voranol™ 220-056N polyol, Voranol™ 232-034N polyol, and Voranol™ 220-110N polyol, all of which are available from DOW™ Chemical.

[0043] The isocyanate component may include 0 to 7 weight percent of a natural oil polyol. All internal values ​​and subranges are disclosed. For example, the isocyanate component may include 1 to 6 weight percent of a natural oil polyol. Suitable natural oil polyols include, but are not limited to, castor oil, corn oil, and soybean oil.

[0044] Polyol component The polyol component may include any natural oil polyol, including, but not limited to, castor oil, corn oil, and soybean oil.

[0045] Additional ingredients and manufacturing of solvent-free adhesives The adhesive compositions of the present disclosure may include one or more additional optional conventional components or additives, including, but not limited to, for example, catalysts, tackifiers, adhesion promoters, antioxidants, fillers, colorants, pigments, surfactants, solvents, polymers (including, for example, thermoplastic resins other than those described herein above), dehydrating agents (including, for example, silanes), benzoyl chloride, other polyols (including, for example, fatty polyols), ultraviolet light indicators, and combinations of two or more thereof.

[0046] The adhesive composition may include, for example, an adhesion promoter. Non-limiting examples of suitable adhesion promoters include coupling agents such as silane coupling agents, titanate coupling agents, and aluminate coupling agents, epoxy resins, phosphoric acid, polyphosphoric acid, and phosphate esters.

[0047] Examples of silane coupling agents useful in the present disclosure include, but are not limited to, aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyl-trimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane; γ-mercaptopropyl-trimethoxysilane; and mixtures thereof.

[0048] Examples of titanate coupling agents useful in the present disclosure include, but are not limited to, tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, tetrastearoxytitanium; and mixtures thereof.

[0049] Examples of epoxy resins useful in the present disclosure include, but are not limited to, a variety of readily available epoxy resins such as bisphenol A-epichlorohydrin (epi-bis) type epoxy resins, novolac type epoxy resins, β-methylepichlorohydrin type epoxy resins, cyclic oxirane type epoxy resins, glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, polyglycol ether type epoxy resins, glycol ether type epoxy resins, epoxidized fatty acid ester type epoxy resins, polycarboxylic acid ester type epoxy resins, aminoglycidyl type epoxy resins, resorcinol type epoxy resins, and mixtures thereof.

[0050] The adhesion promoter can be a phosphate ester compound or an epoxy silane ((3-glycidyloxypropyl)-trimethoxysilane). The phosphoric acid can be incorporated into the polyol component, while the epoxy silane can be incorporated into the isocyanate component. Both the epoxy silane and the phosphoric acid can be incorporated into the polyol component.

[0051] The present disclosure contemplates the use of two components: an isocyanate component and a polyol component. It is also contemplated that the isocyanate component and polyol component of the disclosed adhesive composition can be prepared separately and, if desired, stored until it is desired to use the adhesive composition. The process for making the adhesive composition includes mixing the above-described isocyanate and polyol components to form a curable adhesive composition. In some embodiments, both the isocyanate component and the polyol component are each liquid at 25°C. When it is desired to use the adhesive composition, the isocyanate component and the polyol component are contacted and mixed together, typically in a stoichiometric ratio (NCO / OH) of 1 to 2.5. It is contemplated that contacting these two components initiates a curing reaction in which the isocyanate groups react with the hydroxyl groups to form urethane bonds. The adhesive composition formed by contacting the two components can be referred to as a "curable mixture."

[0052] The mixing of the two components to form the adhesive composition can occur at any suitable time during the process of forming the adhesive composition and applying the adhesive to a substrate, such as before, during, or as a result of the application process. All of this can be performed under ambient room temperature conditions. Heating or cooling can be used as needed. Mixing can be performed using a suitable conventional mixer, such as using an electrically, pneumatically, or otherwise powered mechanical mixer.

[0053] A process for preparing the solvent-based adhesive composition of the present disclosure includes, for example, the steps of: (1) providing an isocyanate component; (2) providing a polyol component; and (3) mixing the two components to form a resin mixture.

[0054] Manufacturing adhesive laminates The adhesive compositions of the present disclosure are useful for bonding substrates together, and the adhesive compositions can be used with a wide variety of suitable substrates, either single or multiple. The substrates can be made of similar or different materials. For example, the substrates can be selected from high-, low-, or medium-density plastics (e.g., polystyrene, polyethylene, ABS, polyurethane, polyethylene terephthalate, polybutylene terephthalate, polypropylene, polyphenylene, polycarbonate, polyacrylate, polyvinyl chloride, polysulfone, and mixtures thereof), paper, wood and reconstituted wood products, polymer-coated substrates, wax-coated paperboard, cardboard, particle board, textiles, leather, and metals (e.g., aluminum, iron, and other non-ferrous metals), metallized plastics (e.g., metallized plastic films), and the like.

[0055] Wet and dry adhesive lamination of multiple substrate layers is possible. The adhesive composition can be applied to the desired substrate using conventional application techniques, such as rotogravure printing, flexography, conventional or airless spraying, roll coating, brush coating, wire wound rod coating, knife coating, or coating processes such as curtain, flood, bell, disk, and dip coating processes. Coating the substrate with the adhesive composition can be done over the entire surface of the substrate or on a portion of the surface of the substrate, such as along the edges or at intermittent locations.

[0056] Test Method Recyclability Recyclability is tested using guidelines proposed by the Association of Plastic Recyclers (APR). 50% recycled blended pellets from PE / PE films laminated with each adhesive are mixed with 50% virgin PE, then foamed and tested for thickness, dart impact, surface indentation, and visually inspected. Tear, tensile strength, and secant line are also tested in both the machine and cross directions. The results of these tests are compared to films made from 100% virgin material.

[0057] Bond strength measurement Laminate samples are cut into 15 mm wide strips and pulled at a rate of 4 in / min in a THWING ALBERT™ QC-3A Peel Tester equipped with a 50 N load cell. When the two films in the laminate separate, the average force during the pull is recorded. If one of the films stretches or breaks, the maximum force or the force at the break point is recorded. Values ​​are the average of three separate sample strips. Initial adhesion or green adhesion is tested as soon as possible after the laminate is made.

[0058] T-peel (90°) adhesive strength at 120°C (hand-assisted T-peel) After curing, the laminated film is cut into 15 mm wide specimen samples for T-peel testing on an Instron 5965U 5974 machine with a crosshead speed of 250 millimeters per minute (mm / min). Three strips are then tested in a warm oven at 120°C, and the average value of the three tested strips is recorded. During the test, the tail of the strip is pulled slightly with a finger to ensure that the tail of the strip remains at a 90° angle toward the peel direction. Bond strength test results are measured in N / 15 mm.

[0059] Tear test Sixteen 6x6 inch square samples are prepared and cut into 3x3 inch squares. These are mounted in clamps parallel to the floor. The film thickness of each 3x3 inch square is measured using a caliper-type gauge measure. The samples are then scored and pulled perpendicularly, and the CD and MD tear is measured.

[0060] Tensile test A 6x6 inch square sample is cut into six 1 inch wide strips. The strips are attached to a tensile gripper and pulled at a rate of 50 mm / min in both the MD and CD directions until they break.

[0061] Haze Test BYK Hazegard-1 is used to measure the haze of a 6x6 inch square sample in accordance with ASTM D1003

[0062] Darts Test The sample film is struck at 3.3 m / s with a standard Instron dart probe polished to a mirror finish. Peak force, peak energy, displacement, and total energy are all measured according to ASTM 7192.

[0063] Compostability test Samples are tested to determine (1) whether they fragment during composting, (2) whether polymer molecules are chemically converted to biomass and other products, (3) whether plants can grow properly in the resulting compost, and (4) whether high levels of metals and other harmful components are introduced. Fragmentation is tested using ISO 20200:2015. Biodegradability is tested using ISO 14855-1:2012. Plant growth in the resulting compost is tested by growing plants in the resulting compost and measuring germination and germinated biomass against a blank. This test is described in more detail in NMX-E-273-NYCE-2019 Appendix A, OECD Test Number 208. NMX is published by Mexico's official federal diary and can be found at https: / / www.dof.gob.mx / nota_detalle.php?codigo=5591696&fecha=16 / 04 / 2020#gsc.tab=0. NOM-004-SEMARNAT-2002 is used to test for the presence of cadmium, chromium, copper, and other metals listed below. NYCE standards are set by the Mexican government and can be found at https: / / nyce.org.mx / catalogodeestandaresnyce / producto / nmx-e-273-nyce-2019-industria-del-plastico-plasticos-compostables-especificaciones-y-metodos-de-prueba / . [Example]

[0064] The materials used are listed in Table 1 below.

[0065] [Table 1]

[0066] Adhesive Products The adhesive formulations shown in Table 2 were made by heating MDI isocyanate until it reached 60°C, at which point the polyol components were added. If two or three polyol components are used, they may be blended together before addition, or they may be added in stages. During polyol addition, the temperature is maintained below 70°C until the desired NCO% is reached. An NCO% of 11 to 19 is preferred.

[0067] [Table 2]

[0068] [Table 3]

[0069] The adhesive was applied to the laminate using a laminating machine designed for solventless bonding applications, such as the LABO COMBI™ 400 Laminator available from Nordeccanica Group. The adhesive was applied onto the first substrate layer, and the first substrate layer was nipped to the second substrate layer. The coating weight during this process was between 1.3 and 4.8 g / m. 2 During the nipping process, a metal cylinder heated to 45°C to 90°C contacts the uncoated side of the first substrate layer, and a rubber roller contacts the uncoated side of the second substrate layer. The resulting laminate structure is then wound up.

[0070] In Table 4 below, the value of each measured property is first presented as the percentage difference between this value and the value measured for a sample composed of pellets made from 100% virgin polyethylene.

[0071] [Table 4]

[0072] [Table 5]

[0073] The samples of the present invention were mixed together and tested for compostability. 100% of the samples were decomposed, and the biodegradability rate compared to the reference material was 105.2%. The results from plants grown in the compost made from the laminate using the composition of the present invention are shown in Table 5, while the results of the heavy metal test are shown in Table 6.

[0074] [Table 6]

[0075] [Table 7]

Claims

1. A laminate produced using a solventless laminating adhesive, a. an isocyanate component, i. 50 to 70 weight percent, based on the weight of the isocyanate component, of an aromatic isocyanate; ii. 0 to 50 weight percent of a polyether polyol, based on the weight of the isocyanate component; iii. 0 to 7 weight percent of a natural oil polyol, based on the weight of the isocyanate component an isocyanate component comprising: b. a polyol component comprising a natural oil polyol; Including, A laminate having a recyclability characteristic of 25% or less.

2. 2. The solventless laminating adhesive of claim 1, wherein the polyol component comprises 60 to 90 weight percent based on the weight of the laminating adhesive.

3. The solventless laminating adhesive of claim 1, wherein said aromatic isocyanate is at least 50% 4-4'-diphenylmethane diisocyanate.

4. The solventless laminating adhesive of claim 1, wherein said aromatic isocyanate is at least 90% 4-4'-diphenylmethane diisocyanate.

5. 10. The lamination adhesive of claim 1 which is polyester-free.

6. A laminate produced using a solventless laminating adhesive, a. an isocyanate component, i. 50 to 70 weight percent, based on the weight of the isocyanate component, of an aromatic isocyanate; ii. 0 to 50 weight percent of a polyether polyol, based on the weight of the isocyanate component; iii. 0 to 7 weight percent of a natural oil polyol, based on the weight of the isocyanate component an isocyanate component comprising: b. a polyol component comprising a natural oil polyol; Including, A laminate that decomposes during composting such that (1) plastic residues cannot be easily distinguished from other organic materials, (2) polymer molecules are chemically converted into biomass and other products, (3) the resulting compost allows for proper plant growth, and (4) the resulting compost eliminates high levels of metals.

7. 7. The solventless laminating adhesive of claim 6, wherein the polyol component comprises 60 to 90 weight percent based on the weight of the laminating adhesive.

8. The solventless laminating adhesive of claim 6, wherein said aromatic isocyanate is at least 50% 4-4'-diphenylmethane diisocyanate.

9. The solventless laminating adhesive of claim 6, wherein said aromatic isocyanate is at least 90% 4-4'-diphenylmethane diisocyanate.

10. 7. The laminating adhesive of claim 6, which is polyester-free.

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