Compostable adhesive composition and laminate

Abstract

This disclosure provides compositions. In one embodiment, an adhesive composition is provided. The adhesive composition comprises a reaction product comprising (A)(i) a dicarboxylic acid, (ii) a CB-CS diol, and (iii) a glycol polyester polyol component, and (B) an aliphatic isocyanate. This disclosure also provides a first substrate and a second substrate, and a laminate having the adhesive composition positioned between the first substrate and the second substrate.

Description

[Technical Field]

[0001] background Adhesives are used throughout the packaging sector. They connect different functional layers to each other to meet packaging requirements such as heat sealability, an attractive appearance, and suitable barrier properties. Adhesives also need to meet processability requirements such as rapid curing, good heat resistance, adequate chemical resistance, and compliance with government food regulations. Polyurethane adhesives are a common material used in packaging applications.

[0002] Sustainability is becoming increasingly important in the packaging industry. Packaging materials made from non-compostable and / or non-biodegradable plastic films are known to have a negative impact on landfills. As consumers become more environmentally conscious, suppliers and processors have been developing recyclable and biodegradable base materials for packaging to mitigate the negative environmental problems associated with conventional flexible packaging.

[0003] Therefore, in this field, there is a recognized need to develop adhesive compositions that possess the necessary functionality (processability, adhesive performance, etc.) and that readily decompose and / or corrode when exposed to stimuli from a biologically active environment. Furthermore, there is a need for compostable polyurethane adhesive compositions for packaging. [Overview of the project]

[0004] This disclosure provides compositions. In one embodiment, an adhesive composition is provided. The adhesive composition comprises a reaction product comprising (A)(i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol polyester polyol component, and (B) an aliphatic isocyanate.

[0005] The disclosure also provides laminates. In embodiments, a laminate is provided, which comprises a first substrate and a second substrate. The adhesive composition is located between the first substrate and the second substrate. The adhesive composition located between the first substrate and the second substrate comprises a reaction product comprising (A) a polyester polyol component comprising (i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol, and (B) an aliphatic isocyanate.

[0006] definition All references to the periodic table refer to the version published by CRC Press, Inc., 1990–1991. References to element groups in this table refer to a new notation used to number the groups.

[0007] For the purposes of U.S. patent practice, the content of any referenced patent, patent application, or publication is incorporated by reference in its entirety, particularly with respect to definitional disclosures (to the extent that they do not conflict with any definitions specifically provided in this disclosure) and general knowledge in the art (or equivalent U.S. editions are incorporated by reference in this way).

[0008] Numerical ranges disclosed herein include all values ​​from the lower limit to the upper limit (including the lower and upper limits). In the case of ranges that include explicit values ​​(e.g., the range of 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values ​​is included (e.g., the above range 1 to 7 includes 1 to 2, 2 to 6, 5 to 7, 3 to 7, 5 to 6, etc.).

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

[0010] "Bio-based" or "bio-based material" refers to material derived from plants and / or other naturally occurring agricultural, marine, and forestry materials. The advantages of bio-based materials lie in their origin and are recognized by the industry. The term "bio-based" refers to raw materials that are at least partially or entirely derived from natural and / or renewable sources. Bio-based materials exclude petroleum-based materials. The term "bio-based material" refers only to the source from which the bio-based material is derived, and not to the production process of the material.

[0011] As used herein, "biomass" refers to organic materials.

[0012] The term "composition" refers to a mixture of materials that constitute a composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0013] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the existence of any additional components, processes, or procedures, whether or not they are specifically disclosed. To avoid any doubt, all compositions claimed through the use of the term “comprising” may, unless otherwise stated, include any additional additives, adjuvants, or compounds, whether or not they are polymers. In contrast, the term “consisting essentially of” excludes any other components, processes, or procedures from the scope of any prior description, except those not essential for operability. The term “consisting of” excludes any components, processes, or procedures that are not specifically described or enumerated. The term “or” refers to the enumerated members individually and in any combination, unless otherwise stated. The use of the singular includes the use of the plural, and vice versa.

[0014] A "dicarboxylic acid" is a compound that contains two carboxyl (-COOH) groups.

[0015] As used herein, "glycol" is a compound having at least two hydroxyl (--OH) groups bonded to two different carbon atoms, each. As an example, the simplest glycol is ethylene glycol, which has the structure HO-CH2-CH2-OH.

[0016] An "isocyanate" is a chemical substance that contains at least one isocyanate group in its structure. The isocyanate group is represented by the formula -N=C=O. An isocyanate containing two or more or at least two isocyanate groups is called a "polyisocyanate". An isocyanate with two isocyanate groups is a diisocyanate, and an isocyanate with three isocyanate groups is a triisocyanate, and so on. Isocyanates can be aromatic or aliphatic.

[0017] A "polyether" is a compound that contains two or more ether linking groups on a straight chain of atoms.

[0018] "Polyester" is a compound that contains two or more ester linking groups on a straight chain of atoms.

[0019] "Polyester polyol" is a compound that is both polyester and polyol.

[0020] A "polymer" is a polymer compound prepared by polymerizing monomers, whether they are of the same type or different types. Therefore, the general term "polymer" encompasses the term "homopolymer" (used to refer to a polymer prepared from only one type of monomer, with the understanding that trace amounts of impurities may be incorporated into the polymer structure), and the term "interpolymer" (used synonymously with "copolymer") includes bipolymers (used to refer to polymers prepared from two different types of monomers), terpolymers (used to refer to polymers prepared from three different types of monomers), and polymers prepared from four or more different types of monomers. Trace amounts of impurities, such as catalyst residues, may be incorporated into and / or within the polymer. It also encompasses all forms of copolymers, such as random, block, etc. While polymers are often described as being "made from" one or more specific monomers, "based on" a specific monomer or monomer type, or "containing" a specific monomer content, it should be noted that in this context, the term "monomer" is understood to refer to the polymerized residue of a specified monomer, and not to the unpolymerized species. In general, polymers as used herein are referred to in terms of "units," which are the polymerized forms of the corresponding monomers.

[0021] A "polyol" is an organic compound containing multiple hydroxyl (-OH) groups. In other words, a polyol contains at least two hydroxyl groups. Non-limiting examples of suitable polyols include diols (containing two hydroxyl groups), triols (containing three hydroxyl groups), and polyhydroxyl-containing polyols.

[0022] A "solvent-free adhesive" is an adhesive composition that does not contain solvents or is substantially free of solvents.

[0023] A "solvent-based adhesive" is an adhesive composition containing any type of organic solvent. As an example, the solvent can be ethyl acetate, methylethylketone (MEK), etc.

[0024] Test method The acid value (or acidity index) was measured according to ASTM D1386 / 7. The acid value is a measure of the amount of carboxylic acid present in a component or composition. The acid value is the number of milligrams of potassium hydroxide required to neutralize the free carboxylic acid present in 1 gram of the substance. The unit of the acid value is mg KOH / g.

[0025] Hydroxyl (OH) value. The OH value was measured according to ASTM E1899-16. The OH value is a measure of the amount of hydroxyl groups present in a polyol, and the OH value is defined as the number of milligrams of potassium hydroxide (KOH) required to neutralize the acetic acid incorporated in the acetylation of 1 gram of a chemical substance containing free hydroxyl groups. The unit of the OH value is mg KOH / g.

[0026] Boil-in-bag test. An 8-inch (20.32 cm) × 12-inch (30.48 cm) laminate is folded to provide a structure of 20.32 cm × 15.24 cm having a first surface and a second surface. Thus, the first surface and the second surface are each formed from the same laminate. The first substrate (polyethylene ("PE") film) of the first surface is in contact with the first substrate (PE film) of the second surface. The above structure has four edges including one folded edge and three open edges. Two of the open edges are heat-sealed to form a pouch. The heat-sealing is performed at 140 °C for 1 second at a pressure of 300 N / 15 mm. Two to three pouches are made from each example.

[0027] For each pouch, fill it with 180 mL of soup (Morton soup, a mixture of soybean oil, ketchup, and vinegar in a 1:1:1 ratio) through the remaining open edge. To prevent heat sealing failure, avoid splashing soup onto the heat sealing area. After filling, heat seal the open edge to minimize air trapping inside the closed pouch. Each closed pouch has four closed edges and an internal space of 18.82 cm × 13.74 cm (filled with soup). Visually inspect each heat seal for integrity to ensure there are no defects in the seal that would cause leakage during testing. Pouches suspected of being defective were discarded and replaced.

[0028] Fill the pot two-thirds full with water and bring it to a vigorous boil. Cover the boiling pot to minimize water and steam loss. During the test, observe the pot to ensure there is enough water to maintain the boil. Place each pouch individually into the boiling water and leave for 30 minutes. Then, remove the pouches from the boiling water and visually inspect them for tunneling, bubbling, blistering, delamination, and / or leaks.

[0029] The pouch was cut open, the soup was emptied, and the pouch was rinsed with soap and water. One or more strips (15 mm x 175 mm) of the laminate were cut out of the pouch (excluding the heat-sealed area). The bond strength of the laminate was measured according to the 90-degree T-type peel test described above. The heat-seal strength of the laminate was measured according to the heat-seal strength test described above. Bond strength and heat-seal strength were measured as soon as possible after the soup was emptied from the pouch. The inside of the pouch was visually inspected for defects.

[0030] Bond strength (180-degree T-peel test). Bond strength was measured according to the 180-degree hand-assisted T-peel test. The laminate was cured in a 40°C oven for 2 days for the initial T-peel bond strength test, then cut into 175mm × 15mm strips (the bond area of ​​each strip was 175mm × 15mm). Bond strength was also measured after a further 5 days of curing following the boil-in-bag test, and again after a further 12 days of curing. The Instron 5943 peel tester was set to a crosshead speed of 254mm / min. During the test, the tail end of the strip was slightly pulled with a finger to ensure that the tail end was maintained at 90 degrees relative to the peel direction, with the tensile direction being 180 degrees. The average bond strength (grams per 25.4 mm ((g / 25.4mm))) was determined from the force-distance profile. Three samples were tested, and the average "bond strength" was reported.

[0031] Brookfield viscosity was measured using a Brookfield viscometer DVII+ with spindle #27 at 20 rpm and a given temperature.

[0032] Compostability. The terms “compostable” and “compostability” encompass elements such as biodegradability, disintegration, and environmental toxicity. The terms “biodegradable,” “biodegradable,” and variations thereof refer to the properties of a material that are broken down by microorganisms. Biodegradability means that a material is broken down over a period of time through the action of microorganisms such as bacteria, fungi, enzymes, and / or viruses. The terms “disintegration” or “disintegration,” and variations thereof, refer to the degree to which a material decomposes and separates. Compostability refers to the ability of a material to biodegrade and directly become carbon dioxide. Environmental toxicity tests determine whether the composted material exhibits any inhibition of plant growth or the survival of soil or other animals. Biodegradability and compostability may be measured by visually inspecting a substrate exposed to a biological inoculation (e.g., bacteria, fungi, enzymes, and / or viruses) to monitor decomposition. Alternatively, the biodegradable substrate conforms to ASTM standard D6400, or the biodegradable substrate conforms to ASTM standard D6868-03.

[0033] The FTIR (Fourier-transform infrared, FTIR) spectrum was obtained by scanning a sample of the adhesive composition using a Thermo Scientific® Nicolet® iS® 5 FTIR spectrometer equipped with an iD7 ATR probe.

[0034] Gel permeation chromatography (GPC). The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of polyester polyols were measured using gel permeation chromatography (GPC). Samples were prepared for GPC analysis by dissolving approximately 20 mg of sample in 10 g of tetrahydrofuran (THF). GPC separation was performed on a Waters Alliance HPLC system using Agilent PLgel 5 μm particle size columns (four columns per set, with pore sizes of 50, 100, 1000, and 10000 Å). Calibration was completed using Agilent Technologies' polystyrene standard PS EasiVial, prepared in THF. Analysis conditions: Column temperature: 40°C • Eluent: Tetrahydrofuran, destabilizer ·Flow rate: 1.0mL / min • Injection volume: 100 μL • Sample concentration: 2.0 mg / mL for polyols, approximately 10 mg / mL for prepolymers. ·Analysis time: 45 minutes • Detectors: Waters refractive index detector and Waters 2489 UV / Vis detector 254nm

[0035] Molecular weight < 1000. The percentage of polymer molecular weights less than 1000 is calculated during the integration and quantification of GPC peaks. The Waters Alliance HPLC system software determines how many of the peaks fall within the 1000 range based on the calibration curve used for integration. Integration is based on the retention time of the standard material used for calibration and the sample peaks. Results are reported as a percentage (%).

[0036] Molecular weight < 500. The percentage of polymer molecular weights less than 500 is calculated during peak integration and quantification. The software determines how many of the peaks fall within the 500 range based on the calibration curve used for integration. Integration is based on the retention time of the standard material used for calibration and the sample peaks. Results are reported as a percentage (%).

[0037] Heat seal strength. The laminate was heat-sealed for 1 second at a sealing temperature of 160°C and a pressure of 40 PSI using an HSG-C heat-sealing machine available from Brugger Company, then cooled to room temperature (23°C) and cut into 175 mm × 15 mm strips (the heat-sealed area of ​​each strip was 175 mm × 15 mm). The heat seal strength of the strips was measured using an Instron Corporation 5940 series single-column tabletop system with a crosshead speed of 254 mm / min. Three samples were tested, and the average heat seal strength was reported in grams per 25.4 mm (g / 25.4 mm).

[0038] The isocyanate group (NCO) content (by weight) was measured according to ASTM D2572-97. The isocyanate index ("NCO index") is the molar ratio of isocyanate groups in the isocyanate component to the amount of hydroxyl groups in the dimer acid polyester polyol component. The NCO index is calculated according to the following formula (1).

[0039]

number

[0040] Particle size. Particle size analysis was performed using a Malvern Mastersizer 3000 laser diffraction particle size analyzer equipped with a Hydro LV liquid dispersion unit. To prepare the sample for analysis, 200 mg of powder was pre-dispersed in 10 mL of 1.5 wt% Brij 35 surfactant solution (excluding PVOH LM-10 added directly to the dispersion unit). The pre-dispersed sample was dropped into the dispersion unit until an obscuration level of 1% was reached. The particle size distribution was calculated using a fitting model with RI=1.50 and AI=0.01. Percentile particle size (Dv90) was used for comparison. The unit of size is micrometers. [Modes for carrying out the invention]

[0041] This disclosure provides adhesive compositions. In embodiments, the adhesive composition is a reaction product of (A) a polyester polyol component and (B) an aliphatic isocyanate. The polyester polyol component (A) is a reaction product of (i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol.

[0042] A. Adhesive composition This adhesive composition contains (A) a polyester polyol component. The polyester polyol component is a reaction product of (i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol.

[0043] In the embodiment, the dicarboxylic acid is an aliphatic dicarboxylic acid. Non-limiting examples of suitable aliphatic dicarboxylic acids include C2-C 20 Dicarboxylic acids, for example, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethylglutaric acid, 2,2-dimethylsuccinic acid, succinic acid, and trimellitic acid, dodecanedicarboxylic acid (C 12Examples include ), and combinations thereof. In the embodiment, the aliphatic dicarboxylic acid is a C2-C6 dicarboxylic acid such as succinic acid.

[0044] (A) The polyester polyol component contains a C3-C6 diol. The C3-C6 diol is a saturated C3-C6 diol. Non-limiting examples of preferred C3-C6 diols include propane-1,3-diol, butane-1,4-diol, and combinations thereof. In this embodiment, the C3-C6 diol is butane-1,4-diol.

[0045] (A) The polyester polyol component contains a glycol. Non-limiting examples of preferred glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, and combinations thereof. In this embodiment, the glycol is diethylene glycol.

[0046] In the embodiment, a catalyst is used to accelerate the reaction of (i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol. Non-limiting examples of suitable catalysts include titanium butoxides, titanium isobutoxides, titanium propoxides, or other alkoxides, and combinations thereof. The condensation polymerization of (i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol was carried out under nitrogen protection, starting at 150°C and gradually increasing to 230°C while removing water, and finally completing the reaction by applying a vacuum.

[0047] In this embodiment, the polyester polyol component (A) is (i) 35% to 65% by weight or 45% to 55% by weight of dicarboxylic acid or succinic acid, (ii) 5% to 25% by weight or 10% to 20% by weight of C3-C6 diol or butane-1,4-diol, (iii) 20% to 40% by weight or 25% to 35% by weight of glycol or diethylene glycol, (iv) A reaction product of a reaction mixture containing or consisting of 0.0001% to 0.005% by weight or 0.0001% to 0.003% by weight of a catalyst or titanium butoxide, wherein the weight percentage (wt%) is based on the total weight of the reaction mixture before the reaction occurs (hereinafter interchangeably referred to as polyester polyol A).

[0048] In embodiments, the polyester polyol component (A) of the adhesive composition includes (i) a dicarboxylic acid, (ii) a C3-C6 diol, and (iii) a glycol, in addition to an enhancer. While not bound by any particular theory, the enhancer is considered to provide further improvements to the compostability and performance of the adhesive composition. Non-limiting examples of suitable enhancers include hydroxyl-functionalized carboxylic acids, caprolactone, hydroxyalkanoates, isosorbide, 2,5-franzicarboxylic acid, and combinations thereof. As used herein, "hydroxyl-functionalized carboxylic acid" is a carboxylic acid having one or more hydroxyl groups in addition to the hydroxyl group present in the carboxylate portion of the carboxylic acid. Non-limiting examples of suitable hydroxyl-functionalized carboxylic acids include lactic acid and glycolic acid.

[0049] In this embodiment, the polyester polyol component is (i) 35% to 65% by weight or 45% to 55% by weight of dicarboxylic acid or succinic acid, (ii) 5% to 25% by weight or 10% to 20% by weight of unsaturated C3-C6 diol or butane-1,4-diol, (iii) 20% to 40% by weight or 25% to 35% by weight of glycol or diethylene glycol, (iv) 1% to 10% by weight of the first enhancer or lactic acid, (v) 2% to 15% by weight of a second enhancer or caprolactone, (vi) A reaction product of a reaction mixture containing or consisting of 0.0001% to 0.003% by weight of a catalyst or titanium butoxide, wherein the weight percentage (wt%) is based on the total weight of the reaction mixture before the reaction occurs (hereinafter interchangeably referred to as polyester polyol B).

[0050] This adhesive composition contains (B) an aliphatic isocyanate. The aliphatic isocyanate does not contain an aromatic ring, or otherwise excludes an aromatic ring. Non-limiting examples of suitable bio-based aliphatic isocyanates include 1,5-pentamethylene diisocyanate, poly(1,5-pentamethylene diisocyanate), and combinations thereof.

[0051] The polyester polyol component (A) reacts with (B) aliphatic isocyanate to form the adhesive composition. The reaction of the adhesive composition in the laminate is carried out at room temperature, or at a high temperature of 25°C to less than 100°C or 25°C to 50°C to enhance adhesive performance.

[0052] In this embodiment, the adhesive composition is (A) 70% to 90% by weight or 80% to 85% by weight of polyester polyether component or polyester polyol A, (B) A reaction product of an adhesive reaction mixture containing or comprising 30% to 10% by weight or 20% to 15% by weight of an aliphatic isocyanate or 1,5-pentamethylene diisocyanate, where the weight percentage (wt%) is based on the total weight of the adhesive reaction mixture before the reaction occurs (hereinafter interchangeably referred to as Adhesive 1). In a further embodiment, Adhesive 1 has a DtCO2 value of more than 90% after 120 days (as described below).

[0053] In this embodiment, the adhesive composition is (A) 70% to 90% by weight or 80% to 85% by weight of polyester polyol component or polyester polyol B, (B) A reaction product of an adhesive reaction mixture containing or comprising 30% to 10% by weight or 20% to 15% by weight of an aliphatic isocyanate or 1,5-pentamethylene diisocyanate or poly(1,5-pentamethylene diisocyanate), where the weight percentage (wt%) is based on the total weight of the adhesive reaction mixture before the reaction occurs (hereinafter interchangeably referred to as Adhesive 2). In a further embodiment, Adhesive 2 has a DtCO2 value of more than 90% after 120 days (as described below).

[0054] In the embodiment, the adhesive composition includes a solvent. The solvent is selected from ethyl acetate, butyl acetate, methyl ethyl ketone, methyl butyl ketone, water, and combinations thereof.

[0055] B. Laminate This disclosure provides a laminate comprising a first substrate, a second substrate, and an adhesive layer between the first and second substrates. The adhesive layer is composed of the adhesive composition. In particular, the adhesive layer is composed of an adhesive composition which is a reaction product of (A) a polyester polyol component comprising (i) a dicarboxylic acid, (ii) a C3-C6 diol, (iii) a glycol, and (iv) an optional enhancer, and (B) an aliphatic isocyanate.

[0056] The laminate includes a first substrate and a second substrate. The first substrate and the second substrate may be the same or different. In one embodiment, the first substrate and the second substrate are the same, and therefore they have the same composition and the same structure.

[0057] In this embodiment, the first substrate and the second substrate are each a film. The film may be a single-layer film or a multilayer film. If the first substrate and / or the second substrate is a multilayer film, the multilayer film may contain two, three, four, five, six, seven, eight, nine, ten, or more layers.

[0058] In the embodiment, the laminate includes more than two substrates, or three, four, or more substrates, and has an adhesive layer between the substrates to bond them together.

[0059] In one embodiment, the film is a single-layer film having one and only one layer.

[0060] In one embodiment, the film includes layers containing components selected from ethylene polymers (PE), propylene polymers (PP), polyamides (such as nylon), polyesters, ethylene vinyl alcohol (EVOH) copolymers, polyethylene terephthalate (PET), ethylene vinyl acrylate (EVA) copolymers, ethylene methyl acrylate copolymers, ethylene ethyl acrylate copolymers, ethylene butyl acrylate copolymers, ethylene acrylic acid copolymers, ethylene methacrylic acid copolymers, ethylene acrylic acid ionomers, methacrylic acid ionomers, maleic anhydride grafted ethylene polymers, polylactic acid (PLA), polystyrene, metal foils, cellulose, cellophane, nonwoven fabrics, and combinations thereof. A non-limiting example of a suitable metal foil is aluminum foil. Each layer of the multilayer film may be formed from the same components or from different components. In one embodiment, the film includes layers containing metal foil.

[0061] In this embodiment, the first substrate and the second substrate are each composed of compostable material for creating a compostable laminate. The compostable material in the first substrate may be the same as or different from the compostable material in the second substrate. Non-limiting examples of compostable materials suitable for the first and / or second substrates include lignin, starch, cellulose materials (paper, cardboard), polylactic acid (PLA), polylactic acid stereocomplex (PLLA-PDLA), polyglycolic acid (PGA), cellophane, polypropylene carbonate (PPG), polybutylene succinate (PBS), polybutylene succinate-cobutylene adipate (PBSA), polybutylene succinate-cobutylene sebacate (PBSSe), polycaprolactone (PCL), and polypentadecanolide, polybutylene adipate-cobutylene terephthalate (PBAT), polybutylene sebacate Examples include polybutylene terephthalate (PBSeT), polybutylene azelate-cobutylene terephthalate (PBAzeT), polybutylene brushlate-cobutylene terephthalate (PBBrasT), poly-3-hydroxybutyrate (PHB), poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P(3HB)-co-P(3HV)), poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P(3HB)-co-P(4HB)), poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (P(3HB)-co-P(3HH)), and films made from combinations thereof.

[0062] In this embodiment, the first substrate and the second substrate each have a thickness of 5 μm, 10 μm, 12 μm, 15 μm, 20 μm, 21 μm to 23 μm, 24 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, or 500 μm.

[0063] Non-limiting examples of suitable methods for applying the adhesive composition to the first substrate and / or the second substrate include brushing, pouring, spraying, coating, roll coating, spreading, and combinations thereof. In embodiments, the adhesive composition is applied at a coat weight of 0.8 g / m 2 ~5.0 g / m 2 、or 1.0 g / m 2 ~4.0 g / m 2 、or 1.5 g / m 2 ~3.0 g / m 2 、or 1.8 g / m 2 ~2.5 g / m 2 between the first substrate and the second substrate.

[0064] In embodiments, the adhesive composition is uniformly applied to the first substrate and then laminated to the second substrate using a laminator, or vice versa. "Uniform application" means that it is continuous (not intermittent) across the entire surface of the substrate and is a layer of the adhesive composition of the same or substantially the same thickness across the entire surface of the substrate. In other words, the adhesive composition is uniformly applied to the first substrate and / or the second substrate, is in direct contact with the substrate surface, the adhesive composition has the same spread or substantially the same spread as each substrate surface, and binds to each other after curing.

[0065] In embodiments, the adhesive layer is in direct contact with the first substrate, and the adhesive layer is also in direct contact with the second layer. As used herein, the terms "in direct contact" or "in direct contact with" refer to a layer configuration in which the substrate is positioned immediately adjacent to the adhesive layer and there is no intervening layer or intervening structure between the substrate and the adhesive layer.

[0066] In embodiments, the adhesive layer is in direct contact with the first substrate, and the adhesive layer is also in direct contact with the second layer. The laminate has the following structure (A). Structure (A) First substrate / adhesive composition / second substrate.

[0067] In one embodiment, the laminate is formed using a laminator such as a Nordmeccanica Labo Combi 400 laminator. In another embodiment, the laminate is formed using a hand laminator such as a ChemInstruments Hot roll Laminator HL-200.

[0068] In this embodiment, the first and second substrates of the laminate are each composed of a compostable material selected from polylactic acid, polybutylene succinate, polycaprolactone, and cellulose material. The first substrate may be composed of the same compostable material as the second substrate, or the first substrate may be composed of a different compostable material than that of the second substrate.

[0069] Rather than being limiting, some embodiments of this disclosure are described in detail in the following examples. [Examples]

[0070] The materials used in the invention's examples ("inventive examples, IE") and comparative samples ("comparative samples, CS") are provided in Table 1 below.

[0071] [Table 1]

[0072] A. Synthesis of polyester polyol components 1, 3, and 4. A 3 L multi-necked round-bottom flask was dried in an oven, purged with nitrogen, and then, under ambient conditions, (i) succinic acid, (ii) butanediol ("BDO"), (iii) and diethylene glycol monomer were added in the amounts listed in Table 2 below (Polyester Polyol 1, 3, 4). The system was vacuumed to less than 60 mTorr and refilled with nitrogen. After four cycles of vacuum / N2 purging, the reactor was placed under a continuous N2 flow and slowly heated. When the reactor temperature reached 100°C, an overhead mechanical stirrer was slowly turned on to agitate the mixture. The reaction temperature was then gradually increased to 150°C and held at this temperature until no more water was produced, and then the temperature was slowly increased to 230°C based on 5°C. The acid value (AV) was monitored when approximately 95% of the theoretical water had been produced. The reactor was maintained at 230°C for 6 hours (hrs) until the AV was less than 10 mg KOH / g. Next, after cooling the reactants to below 150°C, the catalyst (titanium butoxide) was added, and the resin mixture was heated back to 230°C. While maintaining the temperature, a vacuum of 550-650 mTorr was applied for 2 hours, followed by a vacuum of 450-550 mTorr for 2 hours, and then a vacuum of 350-450 mTorr for 1 hour. The total cycle time was approximately 12 hours. The resin was then cooled to 150°C and transferred to a glass bottle. The final product was characterized by its acid value, OH number, viscosity, and molecular weight by gel permeation chromatography (GPC). The polyester polyol components 1, 3, and 4 synthesized herein are interchangeably referred to as polyester polyol 1, polyester polyol 3, and polyester polyol 4, respectively, in Table 2.

[0073] B. Preparation of polyester polyol components 2 and 5. A 3 L multi-necked round-bottom flask was dried in an oven, purged with nitrogen, and then, under ambient conditions, (i) succinic acid, (ii) BDO, (iii) diethylene glycol, and (iv) lactic acid were added in the amounts listed in Table 2 below (Polyester Polyol 2, 5). The system was vacuumed to less than 60 mTorr and refilled with nitrogen. After 4 cycles of vacuum / N2 purging, the reactor was placed under a continuous flow of N2 and slowly heated. When the reactor temperature reached 100°C, an overhead mechanical stirrer was slowly turned on to agitate the mixture. The reaction temperature was then gradually increased to 150°C and held at this temperature until no more water was produced, and then the temperature was slowly increased to 230°C based on 5°C. The acid value (AV) was monitored when approximately 95% of the theoretical water had been produced. The reactor was maintained at 230°C for 6 hours until the AV was less than 10 mg KOH / g. Next, after cooling the reactants to below 150°C, the catalyst (titanium butoxide) was added, and the resin mixture was heated back to 230°C. While maintaining the temperature, a vacuum of 550–650 mTorr was applied for 2 hours, a vacuum of 450–550 mTorr for 2 hours, and a vacuum of 350–450 mTorr for 1 hour. The total cycle time was 12 hours. The resin was then cooled to approximately 150°C, and the measured acid value was less than 0.9 mg KOH / g. (v) The amount of caprolactone (listed in Table 2 below) was added to the reactants, and the reaction mixture was heated to 180°C and maintained at that temperature for 3 hours. FTIR was used to track the reaction, and no caprolactone monomer remained. The total cycle time for the synthesis was 16 hours. It was then cooled to 150°C, and the product was transferred to a glass jar. The final product was characterized by acid value, OH number, viscosity, and molecular weight by gel permeation chromatography (GPC). The polyester polyol components 2 and 5 synthesized in this specification are interchangeably referred to as polyester polyol 2 and polyester polyol 5, respectively, in Table 2.

[0074] [Table 2] % - Weight percentage based on the total weight of polyester polyols

[0075] C. Performance Evaluation A novel solvent-free, compostable adhesive was evaluated using a PLA / / PLA-seal film structure and compared with the conventional commercially available solvent-free adhesive MOR-FREE L75-197 / CR-5. The mixing ratios of the adhesive compositions are shown in Table 3.

[0076] [Table 3] Weight percentage based on the total weight of the composition

[0077] For hand-bonding, various polyester polyols and STABiO® D370N (in the wt% shown in Table 3 below) were dissolved in a high-speed mixer at 1800 rpm for 1 minute to produce the adhesive compositions shown in Table 4 below.

[0078] [Table 4]

[0079] D. Formation of laminates using a pilot laminator PLA / adhesive / PLA-seal laminates were prepared using a pilot coater laminator, Labo Combi 400. For comparative samples, a material roll at a temperature of 40°C was used. In the examples of the present invention, a material roll at a temperature of 60°C was used. Lamination was performed at 100 ft / min using in-line corona treatment. The laminated films were cured at 25°C and 50% humidity for 2 days, and then held in an oven at 45°C for curing. Table 5 shows the bond strength and boil-in-bag bond ("Boil in bag, BIB") strength. Table 6 shows the heat seal bond strength. The FTIR spectra show that the NCO peaks of the adhesives in Examples IE1 and IE2 of the present invention disappeared after 2 days at room temperature and after 1 day at 45°C, indicating complete curing of the adhesive composition of the present invention.

[0080] E. Adhesion results

[0081] [Table 5] * BIB: After boiling in the bag for 30 minutes

[0082] [Table 6]

[0083] Examples 3 (Polyester Polyol 3), 4 (Polyester Polyol 4), 5 (Polyester Polyol 5), and Comparative Sample 1 of the present invention were evaluated by hand drawdown and follow-up performance tests after curing under the same conditions. Ethyl acetate was used as the solvent for preparing the adhesive samples for hand drawdown and hand lamination used to prepare the test laminates. After coating the substrate with the adhesive, it was dried in a 90°C oven for 1 minute and then laminated with a second substrate at 40 psi using a hot roll hand lamination machine. The results are shown in Table 7 below.

[0084] [Table 7]

[0085] Tables 5-7 show that IE1-3 have the same or better adhesive performance compared to conventional non-compostable adhesive compositions.

[0086] F. Evaluation of compostability The compostability (biodegradability) of the adhesive composition of the present invention and the comparative polymer material was evaluated in accordance with the International Organization for Standardization (ISO) guideline 14855-2: Method by analysis of evolved carbon dioxide (ISO 14855-2:2018(E)).

[0087] Test materials. The test materials consist of one natural biopolymer and six synthetic polymers, as provided in Table 8 below.

[0088] [Table 8]

[0089] Route of administration. The test system and route of administration were selected based on ISO guideline 14855-2 (ISO, 2018), taking into consideration the physical / chemical properties of the test materials. The test materials were added directly to the reaction vessel. To promote good contact between the test materials and the inoculant, the test materials were pulverized before being added to the compost, except for cellulose LM10 and PVOH, which have sufficiently small particle sizes.

[0090] Inoculum. The microbial inoculum consisted of compost collected on October 19, 2022, from the West Madison Ag Research Station of the University of Wisconsin (Madison, Wisconsin). The compost was collected two months prior to the start of the experiment and stored in the laboratory until use. Before use, the compost was sieved through a 4 mm sieve and thoroughly homogenized by hand. The moisture content and dry solids content of the homogenized compost were determined to be 50% (wet weight) and 50% (dry weight), respectively, by gravimetric measurement. Similarly, the volatile solids content of the compost was determined to be 47% (dry weight).

[0091] Test Procedure: Biodegradation reaction mixtures were prepared in 1-gallon plastic buckets containing 240g of compost (50% moisture) and 103mL of deionized water, respectively, to a moisture content of 65% (wet weight). After mixing the compost with water, the contents were left at room temperature for 24 hours. Next, 120g (dry weight) of pre-washed sea sand was mixed with the compost to obtain a final mass of approximately 396g of mixture (sand, compost, and water). Then, 20g (dry weight) of reference material (cellulose) or test material was added to the mixture and homogenized with a spatula. The homogenized contents were added to a 1L glass composting container. Inoculant blanks were prepared similarly, except that neither reference material nor test material was added. The composting containers were incubated in the dark or in diffuse light for a specified period. The temperature was maintained at 58°C (±2°C). To prevent widespread channeling and provide uniform attack on the test material, the composting container was shaken weekly to ensure proper moisture distribution. Excess moisture, if present, was removed by injecting dry air or by draining through the air inlet. Visual observations were recorded regarding the compost structure, moisture content and color, fungal growth, exhaust odor, and sample disintegration during weekly shaking and at the end of the test. The incubation period was set to 45 days or longer. At the end of the test, the container was weighed with its contents to determine the concentration of dry solids remaining in the composted material. pH was measured according to test method D1293. If the pH was less than 7, the volatile fatty acid spectrum indicating acidification of the contents in the composting container was measured according to Practice D2908. pH was measured by diluting the sample with distilled water to compost inoculant or residue in a ratio of 5:1 w / w, mixing by manual shaking, and measuring immediately. If more than 2 g of volatile fatty acids are formed per kilogram of dry matter in the composting container, the test will be considered invalid.

[0092] Analytical Method. CO2 levels in the headspace of the reaction vessel were measured using a Columbus Micro-Oxymax automated respiration measurement system (Columbus Instruments, Inc., Columbus, OH). This open-flow respirometer system utilized a paramagnetic O2 sensor with a measurement range of 19–21.0% (volume) oxygen and a non-dispersive infrared CO2 detector with a measurement range of 0–0.8% (volume). To compensate for fluctuations in ambient atmospheric pressure, oxygen and CO2 measurements were normalized to a pressure of 800 mmHg. Before commencing the test, the oxygen and CO2 sensors were calibrated using certified calibration gases (Airgas Great Lakes, Inc.) at two concentrations covering at least 50% of the measurement range. Calibration was also verified after the test to demonstrate consistent sensor operation throughout the test period.

[0093] The pH of each reaction mixture was measured using appropriate pH electrodes and meters. Before each use, the meter / electrode was calibrated at pH 4, 7, and 10.

[0094] Sampling frequency: The concentrations of oxygen and CO2 in the headspace of each reaction vessel were recorded at 6-hour intervals throughout the entire experimental period.

[0095] G. Study-specific parameters Carbon dioxide generation. Using carbon dioxide generation as the primary indicator of biodegradation, the percentage of biodegraded test and / or reference materials was calculated as follows: by subtracting the average cumulative CO2 measurement for the three-inoculation material blank from the cumulative CO2 measurement for each improved reaction mixture at each sampling interval, and dividing the difference by the theoretical amount of carbon dioxide generated by the reference or test material.

[0096]

number

[0097]

number

[0098] The biodegradation process is shown in Table 9 below as the average percentage of biodegradation over incubation periods of 20, 40, 80, and 120 days.

[0099] [Table 9]

[0100] Overall, Examples 1 and 2 of the present invention exhibit superior compostability compared to cellulose, polyvinyl acetate, partially hydrolyzed polyvinyl acetate (KURARAY POVAL® LM10), and polyvinyl alcohol, respectively. The adhesive compositions (particularly IE1 and IE2) have a DtCO2 value of over 90% after 120 days, as shown in Table 9 (IE1 107.2%, IE2 92.9%).

[0101] This disclosure is not limited to the embodiments and examples contained herein, but is specifically intended to include some embodiments and modified forms of those embodiments, including combinations of elements of different embodiments, to the extent that they fall within the scope of the following claims.

Claims

1. An adhesive composition, (A) (i) Dicarboxylic acid, (ii) (C ３ -C ６ ) Diol, (iii) Glycol, Polyester polyol components including, (B) An adhesive composition comprising a reaction composition containing an aliphatic isocyanate.

2. The adhesive composition according to claim 1, wherein the dicarboxylic acid is succinic acid.

3. Said C ３ -C ６ The adhesive composition according to any one of claims 1 to 2, wherein the diol is butanediol.

4. The adhesive composition according to any one of claims 1 to 3, wherein the glycol is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, and combinations thereof.

5. The aforementioned polyester polyol component (A) (i) 35% to 65% by weight of the dicarboxylic acid, (ii) 5% to 25% by weight of the unsaturated C ３ -C ６ Diol, (iii) 20% to 40% by weight of the glycol, and The adhesive composition according to any one of claims 1 to 5, wherein the adhesive composition is a reaction product of a reaction mixture containing (iv) 0.0001% to 0.005% by weight of a catalyst.

6. An adhesive composition according to any one of claims 1 to 5, comprising an enhancer selected from the group consisting of hydroxyl-functionalized carboxylic acids, caprolactone, hydroxyalkanoates, isosorbide, 2,5-franzicarboxylic acid, and combinations thereof.

7. The aforementioned polyester polyol component (A) (i) 35% to 65% by weight of the dicarboxylic acid, (ii) 5% to 25% by weight of the above C ３ -C ６ Diol, (iii) 20% to 40% by weight of the glycol, (iv) 1% to 5% by weight of the first enhancer, (v) A second enhancer in an amount of 2% to 10% by weight, (vi) The adhesive composition according to claim 6, which is a reaction product of a reaction mixture containing 0.0001% to 0.003% by weight of a catalyst.

8. The adhesive composition according to any one of claims 1 to 7, wherein the aliphatic isocyanate is selected from the group consisting of 1,5-pentamethylene diisocyanate, poly(1,5-pentamethylene diisocyanate), and combinations thereof.

9. (A) 70% to 90% by weight of the polyester polyol component, (B) 10% to 30% by weight of the aliphatic isocyanate, The adhesive composition according to any one of claims 1 to 8, comprising:

10. The adhesive composition according to any one of claims 1 to 9, further comprising a solvent.

11. The adhesive composition according to claim 10, wherein the solvent is selected from the group consisting of ethyl acetate, butyl acetate, methyl ethyl ketone, acetone, methyl butyl ketone, water, and combinations thereof.

12. The adhesive composition according to any one of claims 1 to 10, having a DtCO value exceeding 90% after 120 days. ２ value.

13. It is a laminate, The first substrate and A second substrate and The present invention comprises an adhesive layer between the first substrate and the second substrate, wherein the adhesive layer is an adhesive composition, and the adhesive composition is (A) (i) Dicarboxylic acid, (ii) C ３ -C ６ Diol, and (iii) Glycol, Polyester polyol components including, (B) A laminate comprising an aliphatic isocyanate and a reaction product thereof.

14. The laminate according to claim 13, wherein the first substrate and the second substrate are each individually composed of a material selected from the group consisting of polylactic acid, polybutylene succinate, polycaprolactone, and cellulose materials.

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