Bio-based adhesive for laminate

Abstract

The present disclosure provides an adhesive composition. In an embodiment, the adhesive composition includes a reaction product of (A) a bio-based isocyanate component having from 30 wt% to 80 wt% bio-based content comprising (i) an isocyanate-terminated compound, and (ii) an optional first bio-based polyol. The adhesive composition also includes (B) a bio-based polyol component comprising (i) a second bio-based polyol, and (ii) optionally an adhesion promoter. The adhesive composition has greater than 60 wt% of bio-based content.

Description

BIO-BASED ADHESIVE FOR LAMINATEBACKGROUND

[0001] It is known to use adhesive in a lamination process in order to fabricate a multilayer packaging structure. The adhesive provides adhesion and adjoins different functional layers together to meet requirements such as heat sealability, attractive appearance, and good barrier properties. For lamination applications, the adhesive typically requires fast curing, good heat resistance, good chemical resistance, and compliance with food contact regulations for packaging applications. Polyurethane-based adhesives are a common adhesive for making laminates. A polyurethane-based adhesive is typically composed of an isocyanate component and an isocyanate reactive component. The two components are mixed upon application and cured for a few days in laminated rolls before further packaging processing.

[0002] Conventional polyurethane-based adhesives are typically petroleum-based and are not made from sustainable sources. Interest is growing in the adhesive industry for bio-based products that provide more sustainable options compared to their petrochemical counterparts. Bio-based materials contain organic carbon of renewable origin, such as agricultural, plant, marine, or forestry materials. Bio-based materials can reduce dependence on fossil fuels thereby imparting a smaller carbon foot-print, and indirectly tackle climate change by sequestering carbon dioxide (CO2). Despite the growing demand for sustainable packaging solutions based on bio-based raw materials, it is not straightforward to prepare laminating adhesive products from bio-based raw materials. Obstacles exist in delivering bio-based adhesive with comparable physical, chemical and mechanical properties as petrochemical-based adhesives. Accordingly, the art recognizes the need for adhesive compositions formed from bio-based raw materials, the adhesive compositions having greater than 50 wt% bio-based content and exhibiting sufficient adhesion between substrates.SUMMARY

[0003] The present disclosure provides an adhesive composition. In an embodiment, the adhesive composition includes a reaction product of (A) a bio-based isocyanate component having from 30 wt% to 80 wt% bio-based content comprising (i) an isocyanate-terminatedcompound, and (ii) an optional first bio-based polyol. The adhesive composition also includes (B) a bio-based polyol component comprising (i) a second bio-based polyol, and (ii) optionally an adhesion promoter. The adhesive composition has greater than 60 wt% of bio-based content.

[0004] The present disclosure provides a laminate. In an embodiment the laminate includes a first substrate, a second substrate, and an adhesive layer between the first substrate and the second substrate. The adhesive layer comprises an adhesive composition that is a reaction product of (A) a bio-based isocyanate component having from 30 wt% to 80 wt% bio-based content comprising (i) an isocyanate-terminated compound, and (ii) an optional first biobased polyol. The adhesive composition also includes (B) a bio-based polyol component comprising (i) a second bio-based polyol, and (ii) optionally an adhesion promoter. The adhesive composition has a bio-based content greater than 60 wt%.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 shows bond strength of adhesive compositions in Aluminum / adh / PE laminate after 1-day, 7-day, 14-day curing times and after a boil-in-bag test for IE1 and CS2.

[0006] FIG. 2 shows bond strength of adhesive compositions in PET / adh / PE laminate after 1-day, 7-day, 14-day curing times and after a boil-in-bag test for IE1 and CS2.

[0007] FIG. 3 shows bond strength of adhesive compositions in Aluminum / adh / PE laminate (left) and PET / adh / PE structure (right) for IE3 and CS4for laminate after 7-day and 14-day curing times.

[0008] FIG. 4 shows bond strength of adhesive compositions in Aluminum / adh / PE structure (left) and PET / adh / PE structure (right) for I E5 and CS for laminates after 7-day and 14-day curing times.DEFINITIONS

[0009] For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference in their entirety (or its equivalent US version is so incorporated by reference) especially with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and general knowledge in the art.

[0010] The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., a range from 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., the range 1-7 above includes subranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

[0011] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight and all test methods are current as of the filing date of this disclosure.

[0012] "Bio-based" or "bio-based material" refers to a material derived from plants and / or other naturally occurring agricultural, marine, and forestry materials. The benefit of bio-based material resides in its origin and is recognized by the industry. The term "bio-based" refers to a raw material, which is at least partially derived, or wholly derived, from natural and / or renewable sources. A bio-based material is inapposite to, and excludes, petroleum-based material. The term "bio-based" does not refer to the production process of the material but only to the source from which the material is derived.

[0013] "Biomass" as used herein is an organic material.

[0014] "Bio-based content" or "bio%" is determined by the bio-based content of each raw material and its weight percent in the adhesive composition or component thereof. The biobased content can be determined by measuring14C isotope ratio using standardized methods such as ASTM D6866.

[0015] The term "composition" refers to a mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0016] The terms "comprising," "including," "having," and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any succeeding recitation any other component, step, or procedure, excepting 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," unless stated otherwise, refers to the listed members individually as well as in any combination.

[0017] A "dicarboxylic acid" is a compound containing two carboxyl (— COOH) groups.

[0018] An "isocyanate" is a chemical that contains at least one isocyanate group in its structure. An isocyanate group is represented by the formula: — N=C=O. An isocyanate that contains more than one, or at least two, isocyanate groups is a "polyisocyanate." An isocyanate that has two isocyanate groups is a di-isocyanate and an isocyanate that has three isocyanate groups is a triisocyanate, etc. An isocyanate may be aromatic or aliphatic.

[0019] "Organic material" refers to carbon-based compounds, originally derived from living organisms.

[0020] A "polyether" is a compound containing two or more ether linkages in the same linear chain of atoms.

[0021] A "polyester" is a compound containingtwo or more ester linkages in the same linear chain of atoms.

[0022] A "polyester polyol" is a compound that is a polyester and a polyol.

[0023] A "polymer" is a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term "homopolymer" (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term "interpolymer" (which is used interchangeably with the term "copolymer") includes bipolymers (employed to refer to polymers prepared from two different types of monomers), terpolymers (employed to refer to polymers prepared from three different types of monomers), and polymers prepared from more than three different types of monomers. Trace amounts of impurities, for example, catalyst residues, may be incorporated into and / or within the polymer. It also embraces all forms of copolymer, e.g., random, block, etc. It is noted that although a polymer is often referred to as being "made of" one or more specified monomers, "based on" a specified monomer or monomer type, "containing" a specified monomer content, or the like, in this context the term "monomer" is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein arereferred to has being based on "units" that are the polymerized form of a corresponding monomer.

[0024] A "polyol" is an organic compound containing multiple hydroxyl (—OH) groups. In other words, a polyol contains at least two hydroxyl groups. Nonlimiting examples suitable polyols include diols (which contain two hydroxyl groups), triols (which contain three hydroxyl groups), and multi-hydroxyl containing polyols.

[0025] A "solvent-less adhesive" is an adhesive composition that is void of, or substantially void of, a solvent.TEST METHODS

[0026] Acid value The acid value (or acid number) is the number of milligrams of potassium hydroxide required for the neutralization of free carboxylic acids present in one gram of a substance. Units for acid value are mg KOH / g.

[0027] Boil-in-Bag Test. A cured laminate sample (9 inches x 11 inches) was folded over to form a double layer such that the PE film of one layer was in contact with the PE film of the other layer. The edges were trimmed with a paper cutter to obtain a folded piece of 5 inches x 7 inches. The edges were heat sealed to form a pouch with an interior size of 4 inches x 6 inches . The pouches were filled with 100 mL of 1 / 1 / 1 sauce (blend of equal weight of ketchup, vinegar and vegetable oil). After filling, the pouch was sealed in a manner that minimizes the air entrapment in the pouch. The filled pouches were carefully placed in boiling water and kept immersed for 60 minutes. When complete, the extent of tunneling, delamination or leakage was compared with marked pre-existing flaws. The bags were then emptied and cut into 1 inch strips for T-peel bond strength test as soon as possible.

[0028] Bond Strength (180° T-Peel Test). T-peel bond strength was measured on 1-inch strips at a rate of 10 inch / min on a Thwing-Albert tensile tester with a 50N loading cell. Three strips were tested for each laminate and the high and mean strength were recorded along with the failure mode. In case of film tear, the average of high value was reported. In all other failure modes, the average of mean value was reported. Typical failure modes include:AF - Adhesive failure (adhesive on the primary film)AT - Adhesive transfer (adhesive on the secondary film)AS - Adhesive split (adhesive on both sides of the laminate, cohesive failure of the adhesive)FT - Film tear

[0029] Hydroxyl number (OH Number) (or hydroxyl value) is a measure of the number of hydroxyl groups present in a component or a composition. Average hydroxyl number is determined according to ASTM D4274-21.

[0030] Isocyanate group (NCO) content by weight is measured in accordance with ASTM D2572-97.DETAILED DESCRIPTION

[0031] The present disclosure provides an adhesive composition. In an embodiment, the adhesive composition includes a reaction product of (A) a bio-based isocyanate component and (B) a bio-based polyol component. The bio-based isocyanate component (A) includes (i) an isocyanate-terminated compound, and (ii) an optional first bio-based polyol. The biobased isocyanate component has a bio-based content from 30 wt% to 80 wt%. The bio-based polyol component (B) includes (i) a second bio-based polyol, and (ii) optionally an adhesion promoter. The adhesive composition has greater than 60 wt% bio-based content.

[0032] The adhesive composition includes (A) the bio-based isocyanate component. The bio-based isocyanate component (A) includes an isocyanate-terminated compound. The isocyanate-terminated compound can be an aliphatic isocyanate, an aromatic isocyanate, and combinations thereof. The isocyanate-terminated compound can be an isocyanate monomer, a polyisocyanate {e.g., dimers, trimers, etc.) an isocyanate prepolymer, and mixtures thereof. A "polyisocyanate" is a compound that contains two or more isocyanate groups. The bio-based isocyanate component has a bio-based content from 30 wt% to 80 wt%, or from 40 wt% to 70 wt%.

[0033] In an embodiment, the bio-based isocyanate component (A) includes an isocyanate prepolymer that is prepared via reaction between (i) a diisocyanate having 0 wt% bio-based content and (ii) the first bio-based polyol. The first bio-based polyol has a bio-based contentfrom 80 wt% to 100 wt%, or from 90 wt% to 100 wt% (based on total weight of the first biobased polyol). The bio-based isocyanate component (A) has a bio-based content from 30 wt% to 80 wt% or from 40 wt% to 70 wt% based on total weight of the bio-based isocyanate component (A). Nonlimiting examples of suitable diisocyanates with 0 wt% bio-content include methylene diphenyl diisocyanate (MDI).

[0034] Nonlimiting examples of suitable first bio-based polyols with 80 wt% to 100 wt% bio-content include polyester polyols, polyether polyols, polypropylene glycols, polypropanediols, polytetramethylene ether glycols, polyester polyol {e.g., based on ethylene glycol and dimer acid), polybutylene oxide based polyols, natural oil polyols ( / .e., vegetable oils in including castor oil, corn oil, or soybean oil), or mixtures thereof and / or copolymers thereof. Nonlimiting examples of suitable commercial first bio-based polyols include castor oil available from Acme-Hardesty; Vevetol® H1000 available from WeylChem, EMEROX® 14801 available from Emery Oleochemicals; and mixtures thereof.

[0035] In an embodiment, the bio-based isocyanate component (A) includes an isocyanate prepolymer that is prepared via reaction between (i) an aromatic diisocyanate (such as MDI, for example) having 0 wt% bio-based content and (ii) the first bio-based polyol that is polypropanediol. The polypropanediol has a bio-based content from 80 wt% to 100 wt%, or from 90 wt% to 100 wt%. The reaction product of the aromatic diisocyanate and the polypropanediol yields a bio-based isocyanate component (A) having a bio-based content from 30% to 80%, or from 35% to 75%, or from 40% to 60%, or from 40% to 50%.

[0036] In an embodiment, the bio-based isocyanate component (A) consists of a bio-based isocyanate having a bio-based content from 60 wt% to 80 wt% (and no first bio-based polyol). A nonlimiting example of a suitable bio-based isocyanate is a polyisocyanate based on 1,5- pentamethylene diisocyanate having a bio-content of 70%.

[0037] The present adhesive composition includes (B) the bio-based polyol component. The bio-based polyol component (B) includes (i) the second bio-based polyol, and (ii) optionally an adhesion promoter. The bio-based polyol component (B) has a bio-content from 80 wt% to 100 wt%, or from 85 wt% to 95 wt%. Nonlimiting examples of suitable second bio-based polyol include polyester polyols, polyether polyols, polypropylene glycols,polypropanediols, polytetramethylene ether glycols, polyester polyol (e.g., based on ethylene glycol and dimer acid), polybutylene oxide based polyols, natural oil polyols ( / .e., vegetable oils in including castor oil, corn oil, or soybean oil), or mixtures thereof and / or copolymers thereof. Commercial polyols that can be used for the second bio-based polyol include, but are not limited to, castor oil available from Acme-Hardesty; Vevetol® H1000 available from WeylChem, EMEROX® 14801 available from Emery Oleochemicals; and mixtures thereof.

[0038] In an embodiment, the bio-based polyol component (B) includes an optional adhesion promoter in addition to the second bio-based polyol. The adhesion promoter is present in an amount from 0 wt%, or from greater than 0 wt% to 10 wt%, or from 1 wt% to 8 wt%, or from 1 wt% to 3 wt%, based on the total weight of the bio-based polyol component (B). In a further embodiment, the bio-based polyol component (B) includes (i) 95 wt% of the second bio-based polyol and (ii) 5 wt% of the adhesion promoter, based on the total weight of the bio-based polyol component (B). Nonlimiting examples of suitable adhesion promoter include phosphate-ester based polyol ("phosphate ester polyol"), aminosilane, epoxysilane, and combinations thereof. In an embodiment, the adhesion promoter is a phosphate ester polyol.

[0039] The present adhesive composition is the reaction product of bringing the bio-based isocyanate component (A) into contact with the bio-based polyol component (B) and mixing component (A) and component (B) together at a mix ratio to provide a mole ratio of isocyanate groups to hydroxyl groups (NCO / OH ratio in Table 4) from 1.1 to 2.2. Bounded by no particular theory, it is believed that when component (A) and component (B) are brought into contact with each other, a curing reaction begins in which the isocyanate groups react with the hydroxyl groups to form urethane links. The adhesive composition formed by bringing the two components into contact can be referred to as a "curable mixture." The adhesive composition has a bio-based content greater than 60 wt%, or a bio-based content from 61% to 99%, or from 62% to 95%, or from 63% to 93%, or from 64% to 90%, or from 66% to 87%.

[0040] The reaction of component (A) with component (B) may be performed under ambient, room temperature conditions (23°C-25°C, or 25°C). As desired, heating or cooling may beemployed. The mixing can be carried out using a suitable conventional mixer, such as using an electrically, pneumatically, or an otherwise powered mechanical mixer.

[0041] The present adhesive composition is useful for bonding substrates together; the present adhesive composition can be used on a wide variety of substrates. The substrates may be similar materials or dissimilar materials. For example, the substrate may be selected from high, low or medium density plastics {e.g., of a type selected from 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 metal {e.g., aluminum, ferrous as well as other non-ferrous), metallized plastics {e.g., metallized plastic film) or the like.

[0042] Wet and dry bond lamination of a plurality of substrate layers is possible. The present adhesive composition can be applied to desired substrates using conventional application techniques such as rotogravure printing, flexographic printing, conventional or airless spray, roll coating, brush coating, wire wound rod coating, knife coating, or coating processes such as curtain-, flood-, bell-, disc-, and dip-coating processes. Coating a substrate with the adhesive composition may be done over the entire surface of the substrate or to a portion of the substrate's surface, such as along an edge, or at intermittent locations.

[0043] In an embodiment, the present disclosure provides a laminate. The laminate includes a first substrate and a second substrate. The laminate includes an adhesive layer between the first substrate and the second substrate. The adhesive layer is composed of the present adhesive composition. In particular, the adhesive layer is composed of the reaction product of (A) a bio-based isocyanate component and (B) the bio-based polyol component. The biobased isocyanate component (A) has a bio-based content from 30 wt% to 80 wt% and is composed of (i) an isocyanate-terminated compound and (ii) an optional first bio-based polyol. The bio-based polyol component (B) is composed of (i) the second bio-based polyol, and (ii) optionally the adhesion promoter. The adhesive composition has a bio-based content greater than 60 wt%, or a bio-based content from 61% to 99%, or from 62% to 95%, or from 63% to 93%, or from 64% to 90%, or from 66% to 87%.

[0044] In an embodiment, the first substrate of the laminate is a polyethylene film and the second substrate of the laminate is a metal foil film.

[0045] In an embodiment, the first substrate of the laminate is a polyethylene film and the second substrate of the laminate is a polyethylene terephthalate film.

[0046] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.EXAMPLES

[0047] The materials used in the inventive examples ("IE") and comparative samples ("CS") are provided in Table 1 below.

[0048] Table 1: Materials used in the Inventive Examples (IE) and Comparative Samples (CS).

[0049] A. Preparation of isocyanate component BioE

[0050] A dried 2L round bottom flask is equipped with a condenser, an overhead mixer, a thermocouple connected to a temperature controller, and a nitrogen bubbler. After purging the flask with nitrogen, raw materials shown in Table 2 were loaded when the flask was kept warm at 40 °C. The reaction was carried out in the absence of heating until the temperature stopped rising and was stabilized. Heating was then applied to raise the reaction temperature to 78 °C. The reaction was stopped after 2 hours maintenance at 78°C and the product was discharged into a container.

[0051] Table 2. Composition of bio-based isocyanate component (BioE).B. Preparation of polyol component

[0052] Polyol component compositions according to Table 3 below were prepared by blending the raw materials using a high speed Flacktek mixer at 1800 rpm for 2 minutes. The process was repeated if needed until a homogeneous mixture was obtained.

[0053] Table 3. Polyol component compositions used in inventive examples and comparative samples. Bio-based content (when present) is calculated from the starting materials.C. Formation of Adhesive Compositions

[0054] The isocyanate component and polyol component were mixed using a high speedFlacktek mixer at 1800 rpm for 2 minutes. The weight based mix ratio is shown in Table 4. For the hand lamination process described in section D, ethyl acetate was used to dilute the adhesive to solid content of 40-45 wt.% to facilitate coating of adhesives on substrates with target coating weight.

[0055] The components of each inventive example and comparative sample adhesive composition are provided in Table 4.

[0056] Table 4. Adhesive compositions for Inventive Examples 1, 3, and 5 (IE1, IE3, IE5) andComparative Samples 2, 4, and 6 (CS2, CS4, and CS6).

[0057] The percent of bio-based materials in the adhesive compositions was calculated based on the biobased content of the raw materials and their weight percent in the adhesive composition. For instance in IE 1, the percent of biobased materials in the isocyanate component, the polyol component and the total adhesive composition were calculated as shown below:Bio% (Bio-E)=0% x 56 wt% + 100% x 44 wt% = 44 wt%Bio% (OH-4)=100% x 95 wt% + 0% x 5 wt% = 95 wt%Bio% (I El)=44% x 55.6 wt% + 95% x 44.4 wt% = 66.6%

[0058] D. Formation of a Laminate

[0059] Laminate samples were prepared using PET / adhesive / PE and Aluminum / adhesive / PE structures to evaluate the adhesive performance. The PET was a 48 gauge polyester film, the PE was linear low density polyethylene film with 1.5 mil thickness,the Aluminum was aluminum foil and was an 0.00035 mil layer prelaminated to the 48 gauge polyester film.

[0060] The PET substrate and the polyethylene ("PE") substrate each was corona treated before lamination. Comparative and inventive adhesive compositions ("adh") were coated on polyethylene terephthalate ("PET") or aluminum substrates ("Al") with a Meyer bar to achieve coat weight in the range of 0.8-1.2 Ib / ream. Lamination was conducted using a hot oil hand laminator with 150 °F nip temperature, 40 psi nip pressure, and at 27 inches / min speed. The laminate samples were cured under 2 pound weight and at room temperature or 50 °C for up to 14 days.

[0061] The properties of the laminates are provided in Tables 5-8 below.E. Results

[0062] FIG. 1 and FIG. 2 show that IE1 and CS 2 have comparable adhesion performance. Each of IE1 and CS2 contain an isocyanate component based on methylene diphenyl diisocyanate (MDI), and each of IE1 and CS2 contain an isocyanate reactive component that is a polyol blend. IE1 is an inventive adhesive composition with 66.6 wt% bio-based content. CS2 has 0% bio-based content. After 14 days, IE1 has a bond strength that is greater than the bond strength of CS1.

[0063] Table 5. Bond strength comparison of IE1 and CS2 in Aluminum / adh / PE laminate.

[0064] Referring to FIG. 1 and Table 5, where the performance of Inventive Example 1 (adhesive composition with 66.6 wt% bio-based content) is compared to Comparative Sample 2 (0% bio-based content) in a laminate structure including an aluminum substrate and a polyethylene substrate, IE1 demonstrates comparable bond strengths to Comparative Sample 2 after 1 day, 7 day, 14 day curing. Both adhesives maintained their bond strengths after the boil-in-bag tests, demonstrating good product and heat resistance.

[0065] Table 6. Bond strength comparison of IE1 and CS2 in PET / adh / PE laminate.

[0066] Referring to FIG. 2 and Table 6, where the performance of IE1 (an inventive adhesive 66.6 wt% bio-based content) is compared to CS2 (0 wt% bio-based content) in a laminate PET / adh / PE structure. IE1 and CS2 demonstrated strong adhesion shown by the film tear failure mode. Each of IE1 and CS2 showed comparable bond strengths after the boil-in-bag test.

[0067] FIG. 3 shows that IE3 and CS4 have comparable adhesion performance.

[0068] Each of IE3 and CS4 contain an isocyanate component based on an aliphatic isocyanate, and the majority of the polyol component is a polyester polyol. IE3 is an inventive adhesive composition with 83.4 wt% bio-based content. CS4 is an adhesive composition with 0% bio-based content. Both adhesive compositions include an aliphatic isocyanate component and a polyester polyol component.

[0069] Table 7. Bond strength comparison of IE3 and CS4, AI / adh / PE laminate andPET / adh / PE laminate.

[0070] Referring to FIG. 3 and Table 7, where IE3 (83.4 wt% bio-based content) showed comparable bond strength to CS4 (0% bio-based content) in laminate structures Aluminum / adh / PE structure. IE3 showed strong adhesion in PET / adh / PE demonstrated by the film tear failure mode.

[0071] FIG. 4 shows that IE5 and CS6 have comparable adhesion performance. Each of IE5 and CS6 contain an isocyanate component based on an aliphatic isocyanate, and the majority of the polyol component is a polyether polyol. IE5 is an inventive adhesive composition with 86.7 wt% bio-based content. CS6 is an adhesive composition with 0 wt% bio-based content.

[0072] Table 8. Bond strength comparison of IE5 and CS 6.

[0073] Referring to FIG. 4 and Table 8, where the IE5 (86.7 wt% bio-based content) demonstrated comparable performance to CS6 (0 wt% bio-based content) in laminate structures Aluminum / adh / PE structure and PET / adh / PE.

[0074] Tables 5-8 demonstrate that laminates formed with an adhesive layer composed ofIE1, IE3, and IE5 show strong adhesion regardless of the bond value obtained because the laminate is destroyed before any adhesive failure. Each adhesive composition of IE1, IE3, and IE5 has a high bio-content (bio-content of 66%-88%) without negative impact on adhesive performance.

[0075] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.

Claims

CLAIMS1. An adhesive composition comprising: a reaction product of(A) a bio-based isocyanate component having from 30 wt% to 80 wt% bio-based content comprising(i) an isocyanate-terminated compound, and(ii) an optional first bio-based polyol;(B) a bio-based polyol component comprising(i) a second bio-based polyol, and(ii) optionally an adhesion promoter; and the adhesive composition has greater than 60 wt% of bio-based content.

2. The composition of claim 1, wherein the bio-based isocyanate component (A) comprises(i) a diisocyanate having 0 wt% bio-based content; and(ii) the first bio-based polyol, the first bio-based polyol having a bio-based content from 90 wt% to 100 wt%.

3. The composition of claim 1 or 2, wherein the first bio-based polyol is a polyether polyol.

4. The composition of claim 3 wherein the first bio-based polyol is polypropanediol.

5. The composition of claim of any one of claims 1 to 4, wherein the bio-based isocyanate component (A) consists of a bio-based isocyanate having a bio-based content from 60 wt% to 80 wt%.

6. The composition of any one of claims 1 to 5, wherein the bio-based isocyanate is a polyisocyanate based on 1,5-pentamethylene diisocyanate.

7. The composition of any one of claims 1 to 6, wherein the second bio-based polyol is selected from the group consisting of a polyether polyol, a polyester polyol, a natural oil polyol, and combinations thereof.8 The composition of any one of claims 1 to 7, wherein the second bio-based polyol is selected from the group consisting of a polyester polyol based on ethylene glycol and dimer acid, a polypropanediol, and combinations thereof.

9. The composition of any one of claims 1 to 8, wherein the second bio-based polyol is a natural oil polyol.

10. The composition of any one of claims 1 to 9, wherein(A) the bio-based isocyanate component comprises(i) a diisocyanate having 0 wt% bio-based content; and(ii) the first bio-based polyol is a polyether polyol having a bio-based content from 90 wt% to 100 wt%; and(B) the bio-based polyol component comprises(i) castor oil, and(ii) the adhesion promoter that is a phosphate ester polyol.

11. The composition of any one of claims 1 to 10, wherein(A) the bio-based isocyanate component consists of(i) a bio-based isocyanate having a bio-based content from 60 wt% to 80 wt%; and(B) the bio-based polyol component comprises(i) a polyester polyol based on ethylene glycol and dimer acid having a bio-based content from 90 wt% to 100 wt%, and(ii) the adhesion promoter that is a phosphate ester polyol.

12. The composition of any one of claims 1 to 11, wherein(A) the bio-based isocyanate component consists of(i) a bio-based isocyanate having a bio-based content from 60 wt% to 80 wt%; and(B) the bio-based polyol component comprises(i) polypropanediol having a bio-based content from 90 wt% to 100 wt%, and(ii) the adhesion promoter that is a phosphate ester polyol.

13. A laminate comprising: a first substrate; a second substrate; and an adhesive layer between the first substrate and the second substrate, the adhesive layer comprising an adhesive composition comprising a reaction product of(A) a bio-based isocyanate component having from 30 wt% to 80 wt% bio-based content comprising(i) an isocyanate-terminated compound, and(ii) an optional first bio-based polyol;(B) a bio-based polyol component comprising(i) a second bio-based polyol, and(ii) optionally an adhesion promoter; and the adhesive composition has a bio-based content greater than 60 wt%.

14. The laminate of claim 13, wherein the first substrate is a polyethylene film and the second substrate is a metal foil film.

15. The laminate of claim 13, wherein the first substrate is a polyethylene film and the second substrate is a polyethylene terephthalate film.

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