Two-component solvent-based laminating adhesive for medical cold-form packaging.

Abstract

Disclosed is a two-component solvent-based lamination adhesive comprising an isocyanate component and a polyol component, wherein the isocyanate component comprises (1) an isocyanate monomer, a polyisocyanate, an isocyanate prepolymer, or a mixture thereof, and (2) ethyl acetate. The polyol component has a molecular weight of 8000 or greater and a T of less than 5°C. g The composition comprises a polyester polyol (1) having the following structure: (1) a phosphate ester polyol (2) having the following structure: (1) wherein R' is selected from any organic group; and an epoxy resin (3). [Formula 1] TIFF2026505485000013.tif46127

Description

[Technical Field]

[0001] The present disclosure relates to solvent-based laminating adhesives. More specifically, the present disclosure relates to solvent-based laminating adhesives for medical cold-form packaging. The present disclosure also relates to laminates formed using the disclosed solvent-based laminating adhesives. [Background technology]

[0002] 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 different lamination end uses is generally known. For example, adhesives, which are typically applied between laminating films, can be used to produce 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. The performance of adhesives varies depending on the category and the application to which the adhesive is applied.

[0003] There are many types within the category of solvent-based laminating adhesives. One type includes multi-component laminating adhesives. Typically, they are two-component solvent-based laminating adhesives, with a first component containing an isocyanate and a second component containing one or more polyols. Common solvents used in such systems include methyl ethyl ketone, ethyl acetate, toluene, etc.

[0004] The two components of the adhesive composition (i.e., the isocyanate and polyol components) are mixed in a predetermined ratio, thereby forming the adhesive composition. The solvent-borne adhesive composition is then applied to a film or foil substrate. The solvent is allowed to evaporate from the applied adhesive composition. Another film or 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.

[0005] Medical cold-form packages typically include a foil layer, an adhesive layer, and a PVC layer. Bond strength and deep-draw depth are key performance parameters in this application. The oxidizable content of medical cold-form packages is subject to strict government regulations. There is a continuing need for adhesives with low oxidizable content and good bond strength and deep-draw depth. Summary of the Invention

[0006] A two-component solvent-based laminating adhesive is now disclosed, which comprises an isocyanate component and a polyol component. The isocyanate component comprises (1) an isocyanate monomer, a polyisocyanate, an isocyanate prepolymer, or a mixture thereof, and (2) ethyl acetate. The polyol component has (1) a molecular weight of 8000 or greater and a T of less than 5°C. g (2) a phosphate ester polyol of Structure 1, where R' is selected from any organic group; and (3) an epoxy resin. [ka]

[0007] The epoxy resin comprises 14 to 30 dry weight % based on the weight of the polyol component. The ratio of the isocyanate component to the polyol component is 1 to 21 dry weight % based on the weight of the solvent-based laminating adhesive. The total content of the phosphate ester is 0.3 to 2 dry weight % based on the weight of the solvent-based laminating adhesive. Laminates formed from the disclosed solvent-based laminating adhesives are also disclosed. DETAILED DESCRIPTION OF THE INVENTION

[0008] Numerical ranges disclosed herein include all values, including lower and upper limits. Ranges that include explicit values ​​(e.g., ranges of 1, or 2, or 3-5, or 6, or 7) include any subranges between any two explicit values ​​(e.g., the 1-7 range above includes subranges of 1-2, 2-6, 5-7, 3-7, 5-6, etc.).

[0009] The term "composition" refers to a mixture containing the materials that make up the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0010] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional component, step, or procedure, whether specifically disclosed or not. For the avoidance of doubt, all compositions claimed through the use of the term "comprising" may include additional additives, adjuvants, or compounds, whether polymeric or not, unless otherwise stated. On the other hand, the term "consisting essentially of" excludes from the scope of any succeeding recitation 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 defined or listed. The term "or," unless otherwise stated, refers to the listed elements individually as well as in any combination. The use of the singular includes the use of the plural, and vice versa.

[0011] An "isocyanate" is a chemical substance containing at least one isocyanate group in its structure. The isocyanate group is represented by the formula -N=C=O or abbreviated as "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, etc.

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

[0013] A "polyether" is a compound containing two or more ether linkages in the same linear chain of atoms.

[0014] A "polyester" is a compound containing two or more ester linkages in the same linear chain of atoms.

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

[0017] A "polyether polyol" is a compound that contains a polyether and a polyol in the backbone structure of the compound.

[0018] "Film," including when referring to a "film layer" in a thicker article, includes any thin, flat, extruded or cast thermoplastic article having a generally consistent, uniform thickness of about 0.5 millimeters (mm) (20 mils) or less in one dimension, unless the thickness is explicitly specified.

[0019] A "polymer film" is a film made from a polymer or a mixture of polymers. Polymer films typically have a composition of 80 weight percent (wt%) of one or more polymers.

[0020] A "polymer" is a polymeric compound produced by polymerizing monomers of the same or different types. Thus, the generic term "polymer" encompasses the terms "homopolymer" (used to refer to a polymer made from only one type of monomer, with the understanding that trace amounts of impurities may be incorporated into the polymer structure) and "interpolymer," which includes copolymers (used to refer to a polymer made from two different types of monomers), terpolymers (used to refer to a polymer made from three different types of monomers), and polymers made 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. Polymers also encompass copolymers of all types, including random and block copolymers. While polymers are often referred to as being "made from" one or more specific monomers, "based on" a specific monomer or type of monomer, or "containing" a specific monomer content, it is understood that the term "monomer" as used herein refers to the polymerized residue of the specified monomer, and not to the unpolymerized monomer species. Polymers are generally referred to herein as being based on the "units" that are the polymerized form of the corresponding monomers.

[0021] Two-component solvent-based laminating adhesive Two-component solvent-based laminating adhesives are disclosed that include an isocyanate component and a polyol component. The ratio of the isocyanate component to the polyol component is 1 to 21% by dry weight, based on the weight of the solvent-based laminating adhesive. All individual values ​​and ranges between 1 and 21% by weight are disclosed and included herein. For example, the ratio of the isocyanate component to the polyol component may be 1 to 10% by dry weight, 1 to 5% by weight, or 1 to 4% by weight.

[0022] The two-component solvent-based laminating adhesive may contain one or more anti-hydrolysis agents, such as azopyridines or carbodiimides. The two-component solvent-based laminating adhesive may contain an antioxidant. The two-component solvent-based laminating adhesive of claim 1 may be free of silanes, polyether polyols, phenolic epoxy resins, and / or highly reactive amine-initiated polyols.

[0023] The two-component solvent-based laminating adhesive can have a V0 of 0.05 to 1.70, measured as follows. All individual values ​​and ranges are included and disclosed. For example, the two-component solvent-based laminating adhesive can have a V0 of 0.08 to 0.20 Na2S2O3 / ml or 0.10 to 0.16 Na2S2O3 / ml, measured as follows:

[0024] The adhesive compositions of the present disclosure generally include at least one solvent. Suitable solvents include, but are not limited to, ethyl acetate, propyl acetate, methyl ether ketone, methyl butyl ketone, acetone, toluene, and mixtures thereof.

[0025] The amount of solvent used in the present disclosure may be, for example, 20% to 90% by weight, 30% to 80% by weight, or 40% to 70% by weight based on the total amount of components in the adhesive composition.

[0026] The adhesive compositions of the present disclosure may include one or more additional optional conventional components or additives, including, but not limited to, catalysts, tackifiers, adhesion promoters, antioxidants, fillers, colorants, pigments, surfactants, solvents, polymers (including, for example, thermoplastic resins other than those described hereinabove), dehydrating agents (including, for example, silanes), benzoyl chloride, other polyols (including, for example, aliphatic polyols), ultraviolet light indicators, and combinations of two or more thereof.

[0027] Isocyanate component The isocyanate component of the two-component solvent-based laminating adhesive may comprise an isocyanate monomer, an isocyanate prepolymer, a polyisocyanate, or a mixture of two or more thereof. The isocyanate monomer, isocyanate prepolymer, or polyisocyanate may comprise an aliphatic isocyanate, an aromatic isocyanate, or a cyclic isocyanate.

[0028] Aromatic isocyanates useful in the present disclosure 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.

[0029] Some examples of commercially available aromatic components useful in the present disclosure include, for example, ISONATE™ 125M, ADCOTTE™ L76-204, COREACTANT CT™ available from The Dow Chemical Company, DESMODUR™ E2200 / 76 available from The Covestro Company, and mixtures thereof.

[0030] The aliphatic isocyanate in the isocyanate component may be an aliphatic polyisocyanate having 3 to 16 or 4 to 12 carbon atoms in the linear or branched alkylene residue. In addition, in the present disclosure, for example, an alicyclic polyisocyanate containing an alicyclic polyisocyanate having 4 to 18 or 6 to 15 carbon atoms in the cycloalkylene residue is also preferably used.

[0031] Examples of aliphatic and cycloaliphatic polyisocyanates useful in the present disclosure include cyclohexane diisocyanate, methyl cyclohexane diisocyanate, ethyl cyclohexane diisocyanate, propyl cyclohexane diisocyanate, methyl diethyl cyclohexane diisocyanate, propane diisocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, nonane triisocyanate, such as 4-isocyanatomethyl-1,8-octane diisocyanate (TIN), decane diisocyanate and triisocyanate, undecane diisocyanate and triisocyanate, dodecane diisocyanate and triisocyanate, hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H 12 Suitable aliphatic and alicyclic polyisocyanates useful in the present disclosure include, but are not limited to, XDI-based polyisocyanates, H6XDI-based polyisocyanates, XDI isocyanurates, HDI-based polyisocyanates, and H6XDI-based polyisocyanates. 12 Also included are MDI-based polyisocyanates, HDI isocyanurates, and mixtures of two or more thereof.

[0032] Some commercially available examples of aliphatic components useful in the present disclosure include, for example, TAKENATE™ D-110N and TAKENATE™ D-120N available from Mitsui Chemicals, DESMODUR™ N3200, DESMODUR™ Quix 175, and DESMODUR™ 2460M available from The Coverstro Company, and mixtures thereof.

[0033] Additional isocyanate-containing compounds suitable for use in accordance with the present disclosure include, but are not limited to, polyisocyanate of 4-methylcyclohexane-1,3-diisocyanate, 2-butyl-2-ethylpentamethylene diisocyanate, 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate, 2-isocyanatopropylcyclohexyl isocyanate, 2,4'-methylenebis(cyclohexyl)diisocyanate, 1,4-diisocyanato-4-methylpentane, and mixtures of two or more thereof.

[0034] The amount of isocyanate monomer, prepolymer, polyisocyanate, or mixtures thereof can exceed 50 weight percent based on the weight of the isocyanate component. The amount of isocyanate monomer, prepolymer, polyisocyanate, or mixtures thereof may be 50 to 99 weight percent based on the weight of the isocyanate component. All mixtures and individual values ​​are included and disclosed. For example, the amount of isocyanate monomer, prepolymer, polyisocyanate, or mixtures thereof may include upper limits of 99, 95, 90, 85, 80, 75, 70, 65, 60, or 55 weight percent based on the weight of the isocyanate component, to lower limits of 50, 55, 60, 65, 70, 75, 80, 85, 90, or 95 weight percent. The isocyanate component may also include ethyl acetate.

[0035] Polyol component The polyol component has a molecular weight of 8000 or more and a T of less than 5°C. gThe polyester polyol may include a polyester polyol having the formula (I) (Iron Oxide ...

[0036] Examples of suitable polybasic acids useful in the present disclosure include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentane-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and anhydride or ester-forming derivatives of these dicarboxylic acids, and p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives or dimer acids of these dihydroxycarboxylic acids, and mixtures thereof. These polybasic acids may be used alone or in combination of two or more.

[0037] According to the present disclosure, any known polyhydric alcohol can be used. Non-limiting examples of suitable polyhydric alcohols useful in the present disclosure include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, triethylene glycol, polycaprolactone diol, dimer diol, glycols such as bisphenol A and hydrogenated bisphenol A, propiolactone, butyrolactone, ε-caprolactone, 8-valerolactone, and polyesters produced by ring-opening polymerization of cyclic ester compounds such as β-methyl-δ-valerolactone, and one or more monomers including ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene, in a conventional manner with ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, Examples of suitable polyhydric alcohols include polyethers prepared by addition polymerization using one or more compounds containing two active hydrogen atoms, such as 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, as initiators, and mixtures thereof. These polyhydric alcohols may be used alone or in combination of two or more.

[0038] The amount of polyester polyol used in the polyol component can be greater than 50 wt. % based on the weight of the polyol component. The amount of polyester polyol used in the polyol component may be 50 to 70 wt. % based on the weight of the polyol component. All individual values ​​and ranges are included. For example, the amount of polyester polyol used in the polyol component may be 55 to 65 wt. % based on the weight of the polyol component.

[0039] The polyol component may include an epoxy resin. The epoxy resin may comprise 14 to 30 dry weight percent based on the weight of the polyol component. All individual values ​​and ranges are included and disclosed. For example, the epoxy resin may comprise 20 to 25 dry weight percent based on the weight of the polyol component.

[0040] The polyol component may include a phosphate ester polyol having the structure shown in Structure 2, where R' is selected from any organic group.

[0041] [ka]

[0042] In addition to the pendant groups shown in Structure 2, R 1 may or may not have one or more additional pendant —OH groups, and R 1 may or may not have one or more additional pendant groups of Structure 2. Any two or more of the —OH groups and groups of Structure 2 may be selected from R 1 Each —OH group and each group in Structure 2 may or may not be bonded to the same atom of R 1 can be bonded to separate atoms of

[0043] R 1 A convenient way to characterize is to describe the compound as having the following structure 3: [ka]

[0044] where R 1 is the same as Structure 2. Compounds having Structure 3 are referred to herein as "precursor polyols."

[0045] Suitable precursor polyols can have a number average Mw of 90 g / mol or more, 200 g / mol or more, or 400 g / mol or more. Suitable precursor polyols can have a number average Mw of 4000 g / mol or less, 2000 g / mol or less, 1200 g / mol or less, 900 g / mol or less, or 500 g / mol or less. Suitable precursor polyols can have a number average Mw of 200 g / mol to 4000 g / mol, 400 g / mol to 2000 g / mol, 400 g / mol to 1200 g / mol, or 400 g / mol to 900 g / mol.

[0046] Suitable precursor polyols may be higher alkyl polyols, monosaccharides, disaccharides, and compounds having structure 4 below. [ka]

[0047] In the formula, R 2 , R 3 , R 4 , and R 5 are each independently any organic group, and each of n1, n2, and n3 is independently an integer from 0 to 10. In addition to the pendant groups shown in Structure 4, R 2 may or may not have one or more additional pendant groups. Furthermore, any two or more pendant groups may be 2It is understood that n1, n2, and n3 may or may not be bonded to the same atom of the molecule. In some embodiments, there is a mixture of compounds having Structure 4, where the compounds of Structure 4 differ from one another in the value of one or more of the parameters n1, n2, and n3. Such mixtures are described herein by reciting a non-integer value for the parameters n1, n2, or n3, where the non-integer value represents a number average for that parameter. When it is desirable to assess the molecular weight of such a mixture, the number average molecular weight is used.

[0048] In the precursor polyol having structure 4, each pendant group is R 2 In the precursor polyol having structure 4, R 3 , R 4 , and R 5 One or more of R may be a hydrocarbon group having 1 to 4 carbon atoms, 2 to 3 carbon atoms, or 3 carbon atoms. 3 , R 4 , or R 5 may be a linear, cyclic, branched, or combination thereof alkyl group; 3 , R 4 , or R 5 may be a linear or branched alkyl group, and one or more of R 3 , R 4 , or R 5 One or more of R may be a branched alkyl group. 3 , R 4 , or R 5 may be identical to each other.

[0049] In the precursor polyols having structure 4, one or more of n1, n2, and n3 may be 0 to 8. In the precursor polyols having structure 4, one or more of n1, n2, and n3 may be 1 or greater. In the precursor polyols having structure 4, one or more of n1, n2, and n3 may be 6 or less. In the precursor polyols having structure 4, n1, n2, and n3 may be the same.

[0050] The group of precursor polyols having structure 4 is R 2 , R 3 , R 4 , and R 5 and n are alkyl groups. Such precursor polyols are known herein as alkoxylated alkyl triols. In the triol, at least one of n1, n2, and n3 is 1 or greater, and R 2 has the following structure 5: [ka]

[0051] The triols are known herein as alkoxylated glycerols. In the alkoxylated triols, R 3 , R 4 , and R 5 When each of R is a branched alkyl group of exactly 3 carbon atoms, the alkoxylated triol is known herein as a propoxylated triol. 2 A propoxylated triol having structure 5 is known herein as a propoxylated glycerol.

[0052] Among the precursor polyols, the higher alkyl polyol may be a compound having 10 carbon atoms or less, a compound having 6 carbon atoms or less, a compound having 3 carbon atoms or less, or glycerol.

[0053] The precursor polyol may be a higher alkyl polyol and a compound having the structure 4, where n1 = n2 = n3 = 0 and R 2 When is either an alkyl group or an alkyl group containing a hydroxyl group, the compound having structure 4 is a higher alkyl polyol.

[0054] The group of precursor polyols may be alkyltriols and alkoxylated alkyltriols. Among these compounds are glycerol and alkoxylated glycerols. Among the alkoxylated glycerols is propoxylated glycerol.

[0055] The phosphate ester compound may be the reaction product of a precursor polyol and a reactant comprising a phosphoric acid. The resulting phosphate ester compound has the chemical structure of Structure 2.

[0056] The amounts of phosphoric acid and precursor polyol are as follows: M p :M x is chosen to determine the ratio of M hy = number of hydroxyl groups per precursor polyol molecule, N x =M hy -2, M x = (number of moles of precursor polyol) x (N x ), and M p = number of moles of phosphorus atoms contained in a phosphoric acid type acid.

[0057] Generally, M p :M x The ratio of M is 0.1:1 or more, 0.2:1 or more, 0.5:1 or more, or 0.75:1 or more. p :M x The ratio may be 1.1:1 or less.

[0058] Typically, the weight ratio of phosphoric acid to precursor polyol is at least 0.005:1, at least 0.01:1, or at least 0.02:1. The weight ratio of phosphoric acid to precursor polyol may be at most 0.3:1, at most 0.2:1, or at most 0.12:1.

[0059] Phosphoric acid-type acids can contain polyphosphoric acid. Generally, the amount of polyphosphoric acid in a phosphoric acid-type acid is 75% by weight or more, 80% by weight or more, or 90% by weight or more, based on the weight of the phosphoric acid-type acid. Polyphosphoric acid is available in various grades, each characterized by a percentage. For purposes of determining grade, it is first recognized that the content of pure monomeric orthophosphoric acid, phosphorus pentoxide, is considered to be 72.4%. Any grade of polyphosphoric acid can be analyzed such that one mole of polyphosphoric acid (formula weight, designated "Fppa") contains the number of moles of phosphorus pentoxide, designated "Nppo," and the percent phosphorus pentoxide ("PCppo") is given by PCppo = (Nppo x 142) / Fppa, expressed as a percentage. The grade of the polyphosphoric acid is then the ratio, designated as a percentage: Grade = PCppo / 72.4.

[0060] The polyphosphoric acid used may have a grade of 100% or more, or 110% or more, or may have a grade of 150% or less, or 125% or less.

[0061] Further information regarding suitable phosphate esters and the preparation of such suitable phosphate esters can be found, for example, in PCT Publication No. WO / 2015 / 168670.

[0062] The phosphate ester may comprise 0.3 to 2 dry weight percent based on the weight of the solvent-based laminating adhesive. All individual values ​​and ranges are included. For example, the phosphate ester may comprise 0.5 to 1 dry weight percent based on the weight of the solvent-based laminating adhesive. The phosphate ester may be included in the isocyanate component rather than the polyol component.

[0063] The phosphate esters may have an NCO% of up to 14. The phosphate esters may have an NCO% of 12-14. All individual internal values ​​and ranges are disclosed and included. For example, the phosphate esters may have an NCO% of 12.5-13.5.

[0064] Formation and Use of Adhesive Compositions It is contemplated in the present disclosure that two components are used: an isocyanate component and a polyol component. It is also contemplated that the isocyanate and polyol components of the disclosed adhesive compositions can be prepared separately and, if desired, stored until use of the adhesive composition is desired. The process for preparing the adhesive composition includes mixing the isocyanate and polyol components to form a curable adhesive composition. In some embodiments, both the isocyanate and polyol components are each liquid at 25°C. When it is desired to use the adhesive composition, the isocyanate and polyol components are contacted with each other, typically mixed together in a stoichiometric ratio ((NCO / OH)) of 1 to 2.5. It is contemplated that upon contact of these two components, a curing reaction begins in which the isocyanate groups react with the hydroxyl groups to form urethane linkages. The adhesive composition formed by contacting the two components can be referred to as a "curable mixture."

[0065] The mixing of the two components to form the adhesive composition may occur at any suitable point in 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 these steps may be performed under ambient room temperature conditions. Heating or cooling may be used as desired. Mixing may be performed using a suitable conventional mixer, such as an electric, pneumatic, or other powered mechanical mixer.

[0066] A process for making the solvent-based adhesive composition of the present disclosure includes, for example, step (1) providing an isocyanate component, step (2) providing a polyol component, step (3) mixing the two components to form a resin mixture, step (4) diluting the resin mixture in a solvent to form a diluted resin mixture having an application solids content of 25 wt% to 55 wt%, 30 wt% to 45 wt%, or 35 wt% to 40 wt%, based on the total weight of the diluted resin mixture, and step (5) removing the solvent from the composition after applying the composition to a substrate and before curing the composition to form the adhesive composition.

[0067] Also disclosed herein is a process for forming a laminate using the adhesive composition of the present disclosure. The adhesive composition, such as the adhesive composition described above, may be in a liquid state at 25°C. Even if the composition is solid at 25°C, the composition may be heated to convert it to a liquid state if necessary. Solvent is added to the mixed adhesive composition until the desired solids content is reached. Solids contents of 25% or higher can be used.

[0068] The adhesive compositions of the present disclosure are useful for bonding substrates together, and the adhesive compositions can be used on a wide variety of suitable substrates, either single or multiple. The substrates may be made of similar or different materials. For example, the substrates may 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 recycled 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.

[0069] 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, flexographic printing, conventional or airless spraying, roll coating, brush coating, wire-wound rod coating, knife coating, or coating processes such as curtain coating, flood coating, bell coating, disk coating, dip coating, etc. Coating the substrate with the adhesive composition can be carried out over the entire surface of the substrate or over a portion of the surface of the substrate, for example along the edge or in intermittent locations. Once applied to the substrate, the adhesive composition is dried, such as by applying heat and air currents, or any other suitable conventional method to remove substantially all residual solvent present in the adhesive composition.

[0070] Laminates containing the solvent-based adhesive composition of the present disclosure can be formed by applying the adhesive to at least one of two different substrates, combining the substrates together so that the adhesive is disposed between the surfaces of the two substrates, and then curing the adhesive to form a bond between the two substrates. The substrate may include, for example, two separate films, each of which can be made of a different material or the same material. Typically, a layer of the adhesive composition is applied to the surface of the film. The layer of the curable adhesive composition mixture applied to the surface of the film has a thickness of 1 micron (μm) to 5 μm. As used herein, a "film" is any structure in which one dimension of the structure is 0.5 mm or less and both of the other two dimensions of the structure are 1 centimeter (cm) or greater.

[0071] The surface of another film is contacted with a layer of the curable mixture to form an uncured laminate. The curable mixture is then cured or allowed to cure naturally. The uncured laminate can be subjected to pressure, for example, by passing through nip rollers, which may or may not be heated. The uncured laminate can also be heated to accelerate the curing reaction.

[0072] Suitable substrates used to form the laminate structure include films such as paper, woven and nonwoven fabrics, polymer films, metal foils, metallized polymer films, and combinations thereof. The substrates are layered to form the laminate structure, and the adhesive composition of the present disclosure adheres one or more substrates together. The film can optionally have a surface on which an image is printed with ink. The ink can be in contact with the adhesive composition. The film can be a polymer film, a metallized polymer film, or a polymer film. [Example]

[0073] The following examples are presented to further illustrate the present disclosure, but should not be construed as limiting the scope of the claims. Unless otherwise stated, implicit from context, or customary in the art, all parts and percentages are by weight and all test methods are current as of the filing date of this disclosure.

[0074] The various raw materials or ingredients used in the inventive examples (Inv. Ex.) and comparative examples (Comp. Ex.) are set forth below in Table 1. All commercial samples are available from Dow Chemical.

[0075] Table 1 Raw materials [Table 1]

[0076] Table 2. Compositions of two-component solvent-based laminating adhesives Note: The solids content of all samples in Table 2 is 30% and all percentages are weight percent based on the weight of the OH component. [Table 2]

[0077] Table 3 Composition of NCO-containing phosphate ester components [Table 3]

[0078] General manufacturing method of OH component The OH component is a solution of high molecular weight polyester polyol, epoxy resin, polycarbodiimide, and phosphate ester, all dissolved in an organic solvent, as shown in Table 2. Before charging the raw materials into the reactor, the water content of all raw materials should be less than 500 ppm. Nitrogen is used during the entire stirring process to avoid moisture contamination. The solution system is maintained at room temperature for 0.5 hours at a rotation speed of 50 RM. Finally, the final product is filled into a well-sealed steel bottle under nitrogen protection.

[0079] Method for producing NCO-containing phosphate ester component SR-F1 The phosphate-functional isocyanate compound of the present invention was synthesized according to the composition listed in Table 3. Desmodur 2460M and Mor-free 88-138 were charged into a 1000 mL glass reactor and carefully mixed according to the composition shown in Table 3. After all raw materials were added, heating was initiated. When the temperature of the raw material mixture reached approximately 60°C, the rotation speed was increased to 50 RM. Nitrogen was introduced throughout the entire process to protect the system from moisture. When the reaction temperature reached approximately 80°C-85°C, the cooling process was initiated and the reaction was maintained at 80°C-85°C for 2 hours. Once the NCO value reached the design value, the reactor was cooled as quickly as possible. The system was cooled to 60°C-70°C, and ethyl acetate was charged into the glass reactor. The rotation speed was maintained at 50 RM for 20 minutes. The final product was then filled into a well-sealed steel bottle under nitrogen protection.

[0080] Coating and Lamination Processes Prior to lamination, nylon (NY) and polyvinyl chloride (PVC) films are stored for 5 days at 50°C / 85°R relative humidity, simulating film storage conditions. Coating and lamination are carried out on an SDC Labo-Combi 400 machine. The nip temperature is maintained at 70°C at a speed of 100 m / min during the entire lamination process. The coating weight is 4-4 g / m. 2 The NY / foil is laminated first. The laminated film NY / foil is then cured at 60°C / 85°R.H. for 7 days before testing. After curing, the laminated NY / foil was laminated with PVC according to the process described above.

[0081] Table 4 Performance results [Table 4]

[0082] method T-peel (90°) adhesive strength at 120°C (manually assisted T-peel) After curing, the laminated film is cut into 15 mm wide strips for T-peel testing on an Instron 5965U5974 machine at a crosshead speed of 250 mm / min. Three strips are tested in a hot air oven at 120°C and an average value is taken. During the test, the tail of the strip is pulled slightly with a finger to ensure that the tail remains at a 90° angle to the peel direction. Results are reported in N / 15 mm.

[0083] Deep drawing test (DDT) The cured laminate film was cut into 8 cm x 12 cm pieces and then placed on the platform of an SDCK-004A automatic deep-drawing machine for evaluation. The machine was operated with specific parameters for deep-drawing applications, adjusting the air pressure to 0.5 MPa and maintaining the die punch speed at 100 mm / min. The deep-drawing test depth was set to 5 mm for all laminates. The appearance of the laminate after deep-drawing application was checked, and the presence of bubbles, tunnels, delamination, and broken substrates was noted. After punching, the laminate was heated to 100°C in a hot air oven for 1 hour, and then the appearance was checked again.

[0084] Titration of easily oxidizable substances V (Na2S2O3 / ml) The cured laminated film is cut into 3 cm x 0.3 cm pieces, and then these small pieces are placed in a tightly sealed glass reactor with 200 ml of distilled water at 70 °C for 2 hours. 20 ml of the aqueous extraction solution is heated to 100 °C for 3 minutes while adding 20 ml of potassium permanganate solution (0.002 mol / L) and 1 ml of sulfuric acid solution (0.1 mol / L). The resulting solution is then cooled to room temperature as quickly as possible. 0.1 g of potassium iodide is added, and the solution is allowed to stand for 5 minutes. 0.01 mol / L aqueous sodium thiosulfate solution is used for titration. Five drops of starch solution are added as an indicator. The amount of sodium thiosulfate solution consumed until the mixed solution becomes transparent is recorded as V1. The same steps are repeated using 20 ml of distilled water instead of the aqueous extraction solution, and the amount of sodium thiosulfate solution consumed, V1, is recorded as V2. The difference between V1 and V2 is measured as the oxidizable substance release, V0 (NaSO / ml).

Claims

1. an isocyanate component (a) comprising (i) an isocyanate monomer, a polyisocyanate, an isocyanate prepolymer, or a mixture of two or more thereof, and (ii) ethyl acetate; Molecular weight of 8000 or more and T of less than 5°C ｇ a polyester polyol (i) having the formula a phosphate ester polyol (ii) having the following structure, in which R′ is selected from any organic group; 【Transformation 6】 a polyol component (b) containing an epoxy resin (iii); and a two-component solvent-based laminating adhesive, 1. A two-component solvent-based laminating adhesive, wherein the epoxy resin comprises 14 to 30 dry weight percent based on the weight of the polyol component, the ratio of the isocyanate component to the polyol component is 1 to 21 dry weight percent based on the weight of the solvent-based laminating adhesive, and the total content of the phosphate esters is 0.3 to 2 dry weight percent based on the weight of the solvent-based laminating adhesive.

2. 10. The two-component solvent-based laminating adhesive of claim 1, wherein the phosphate ester comprises the following structure, where R' is selected from any organic group: 【Transformation 7】

3. 10. The two-component solvent-based laminating adhesive of claim 1 further comprising an additional anti-hydrolysis agent such as an azopyridine or a carbodiimide.

4. 10. The two-component solvent-based laminating adhesive of claim 1 further comprising an antioxidant.

5. 10. The two-component solvent-based laminating adhesive of claim 1 which is silane-free.

6. 10. The two-component solvent-based laminating adhesive of claim 1, which is free of polyether polyols.

7. 10. The two-component solvent-based laminating adhesive of claim 1, which is free of phenolic epoxy resins.

8. 10. The two-component solvent-based laminating adhesive of claim 1, which does not contain a highly reactive amine-initiated polyol.

9. V0 measured as described herein is between 0.05 and 1.70 Na ２ S ２ O ３ 10. The two-component solvent-based laminating adhesive of claim 1, wherein the adhesive has a viscosity of 1000 psig / ml.

10. V0 measured as described herein is between 0.08 and 0.20 Na ２ S ２ O ３ 10. The two-component solvent-based laminating adhesive of claim 1, wherein the adhesive has a viscosity of 1000 psig / ml.

11. 10. The two-component solvent-based laminating adhesive of claim 1, wherein said phosphate ester has an NCO % of 14 or less.

12. The two-component solvent-based laminating adhesive of claim 1, wherein the phosphate ester has an NCO % of 12-14.

13. A laminate formed from the solvent-based laminating adhesive of claim 1.

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