Two-component solvent-based laminating adhesive for medical cold-formed packaging

Abstract

Disclosed is a two-component solvent-borne lamination adhesive comprising an isocyanate and a polyol component wherein the isocyanate component comprises: (1) an isocyanate monomer, a polyisocyanate, an isocyanate prepolymer, or a mixture of these; and (2) ethyl acetate. The polyol component comprises: (1) a polyester polyol having a molecular weight greater than or equal to 8000 and a Tg less than 5 DEG C; (2) a phosphate polyol of structure [1] wherein R'is selected from any organic group, and (3) an epoxy resin.

Description

Technical Field

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

[0002] Adhesive compositions can be used for a variety of purposes. For example, some adhesives are used to adhere two or more film layers of a substrate together to form a composite film (i.e., a laminate comprising two or more film layers). Examples of substrates typically include polyethylene, polypropylene, polyester, polyamide, metal, paper or cellophane, etc. The use of adhesives in various lamination end-use applications is well known. For example, adhesives typically applied between laminating films can be used to make film / film laminates and film / foil laminates, which are used in the flexible packaging industry for food packaging, pharmaceutical packaging, and industrial consumable packaging, particularly for food packaging. Laminating adhesives can generally be divided into three categories: (1) solvent-based laminating adhesives, (2) solvent-free laminating adhesives, and (3) water-based laminating adhesives. The properties of the adhesive vary depending on the category and the application to which the adhesive is applied.

[0003] Within the category of solvent-based laminating adhesives, there are many types. One type includes multi-component laminating adhesives. Typically, a two-component solvent-based laminating adhesive includes a first component containing an isocyanate and a second component containing one or more polyols. Common solvents used in this system include methyl ethyl ketone, ethyl acetate, toluene, and the like.

[0004] The two components of the adhesive composition (i.e., isocyanate and polyol component) are combined in a predetermined ratio to form an adhesive composition. The adhesive composition, which is then carried in a solvent, is applied to a film / or foil substrate. The solvent is evaporated from the applied adhesive composition. Another film / or foil substrate is then brought into contact with another substrate to form a curable laminated structure. The laminated structure is cured to combine the two substrates together.

[0005] Medical cold-form packaging typically comprises a foil layer, an adhesive layer, and a PVC layer. Bond strength and deep draw depth are key performance parameters for this application. The content of easily oxidizable substances in medical cold-form packaging is strictly regulated by the government. There is a continuing demand for adhesives with low levels of easily oxidizable substances while maintaining good bond strength and deep draw depth. Summary of the Invention

[0006] Disclosed is a two-component solvent-based laminating adhesive comprising 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 comprises: (1) a polyol having a molecular weight greater than or equal to 8000 and a T g A polyester polyol having a temperature of less than 5°C; (2) a phosphate polyol of structure 1, wherein R' is selected from any organic group; and (3) an epoxy resin.

[0007] [Structure 1]

[0008] 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. The total content of the phosphate ester is 0.3 to 2 dry weight percent based on the weight of the solvent-based laminating adhesive. Laminates formed from the disclosed solvent-based laminating adhesive are also disclosed. DETAILED DESCRIPTION

[0009] The numerical ranges disclosed herein include all values ​​from and including the lower and upper limits. For ranges containing specific values ​​(e.g., a range from 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two specific values ​​is included (e.g., the above range 1 to 7 includes subranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6, etc.).

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

[0011] The terms "comprising," "including," "having," and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not they are specifically disclosed. For the avoidance of any doubt, all compositions claimed through use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless indicated to the contrary. In contrast, the term "consisting essentially of excludes from the scope of any subsequent statement any other components, steps, or procedures, except those that are not essential to operability. The term "consisting of excludes any component, step, or procedure not specifically described or listed. Unless otherwise stated, the term "or" refers to the members listed individually as well as in any combination. The use of the singular includes the use of the plural and vice versa.

[0012] An "isocyanate" is a chemical substance that contains at least one isocyanate group in its structure. An isocyanate group is represented by the formula: N=C=O, or abbreviated as "NCO." Isocyanates containing more than one or at least two isocyanate groups are "polyisocyanates." An isocyanate with two isocyanate groups is a diisocyanate, and an isocyanate with three isocyanate groups is a triisocyanate, and so on.

[0013] A "polyisocyanate" is a molecule containing at least two isocyanate groups.

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

[0015] A "polyester" is a chemical compound containing two or more ester linkages in the same linear chain of atoms.

[0016] 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 having two OH groups, triols having three OH groups, and tetraols having four OH groups.

[0017] "Polyester polyol" is a compound containing polyester and polyol in the backbone structure of the compound.

[0018] "Polyether polyols" are compounds containing polyethers and polyols in the backbone structure of the compound.

[0019] Unless thickness is specifically specified, "film" (including when referring to a "film layer" in a thicker article) includes any thin, flat extruded or cast thermoplastic article having a generally uniform and uniform thickness in one dimension of about 0.5 mm (20 mils) or less.

[0020] A "polymer film" is a film made from a polymer or polymer mixture. A polymer film typically consists of 80% by weight (wt%) of one or more polymers.

[0021] A "polymer" is a polymeric compound prepared by polymerizing monomers, whether of the same or different types. Thus, the generic term polymer encompasses the term "homopolymer" (used to refer to polymers 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," which includes copolymers (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 more than three different types of monomers. Trace amounts of impurities (e.g., catalyst residues) may be incorporated into and / or within the polymer. It also encompasses all forms of copolymers, such as random copolymers, block copolymers, and the like. It should be noted that while polymers are often referred to as being "made from" one or more specific monomers, "based on" a specific monomer or monomer type, "containing" a specific monomer content, etc., in this context, the term "monomer" is understood to refer to the polymerized residue of the specific monomer, not to unpolymerized material. Generally, a polymer herein refers to a polymer based on "units," which are the polymerized form of the corresponding monomer.

[0022] Two-component solvent-based laminating adhesive

[0023] Disclosed is a two-component solvent-based laminating adhesive comprising an isocyanate component and a polyol component. Based on the weight of the solvent-based laminating adhesive, the ratio of the isocyanate component to the polyol component is from 1% to 21% by dry weight. All individual values ​​and ranges between 1 wt.% and 21 wt.% are disclosed and included herein. For example, the ratio of the isocyanate component to the polyol component can be from 1% to 10% by dry weight, from 1% to 5% by dry weight, or from 1% to 4% by dry weight.

[0024] 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 silicone resin, polyether polyol, phenolic epoxy resin, and / or highly reactive amine-initiated polyol.

[0025] The V0 of the two-component solvent-based laminating adhesive (measured as described below) can be from 0.05 to 1.70. All individual values ​​and ranges are included and disclosed. For example, the V0 of the two-component solvent-based laminating adhesive (measured as described below) can be from 0.08 Na2S2O3 / ml to 0.20 Na2S2O3 / ml or from 0.10 Na2S2O3 / ml to 0.16 Na2S2O3 / ml.

[0026] The adhesive composition of the present disclosure generally includes at least one solvent. Suitable solvents may include, but are not limited to, ethyl acetate, propyl acetate, methyl ether ketone, methyl butyl ketone, acetone, toluene, and mixtures thereof.

[0027] The amount of the solvent used in the present disclosure may be, for example, from 20 wt % to 90 wt %, from 30 wt % to 80 wt %, or from 40 wt % to 70 wt %, based on the total amount of components in the adhesive composition.

[0028] The adhesive compositions of the present disclosure may include one or more additional optional conventional ingredients 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 discussed above), dehydrating agents (including, for example, silanes), benzoyl chloride, other polyols (including, for example, aliphatic polyols), ultraviolet indicators, and combinations of two or more of these.

[0029] Isocyanate component

[0030] The isocyanate component of the two-component solvent-based laminating adhesive may include an isocyanate monomer, an isocyanate prepolymer, a polyisocyanate, or a mixture of two or more of these. The isocyanate monomer, isocyanate prepolymer, or polyisocyanate may contain an aliphatic isocyanate, an aromatic isocyanate, or a cyclic isocyanate.

[0031] Aromatic isocyanates useful in the present disclosure may include, for example, one or more polyisocyanate compounds, including, but not limited to, 1,3- and 1,4-phenylene diisocyanates; 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.

[0032] Examples of some commercial aromatic-based components useful in the present disclosure may include, for example, Isonate available from The Dow Chemical Company. TM 125 M, ADCOTTE TM L76-204、COREACTANTCT TM ; Desmodur available from The Covestro Company TM E 2200 / 76; and mixtures thereof.

[0033] The aliphatic isocyanate in the isocyanate component can be an aliphatic polyisocyanate having 3 carbon atoms (C) to 16 C or 4 C to 12 C in the linear or branched alkylene residue. Also suitable for use in the present disclosure are cycloaliphatic polyisocyanates, including, for example, alicyclic polyisocyanates having 4 C to 18 C or 6 C to 15 C in the cycloalkylene residue.

[0034] Examples of suitable aliphatic and cycloaliphatic polyisocyanates that can be used in the present disclosure include, but are not limited to, cyclohexane diisocyanate, methylcyclohexane diisocyanate, ethylcyclohexane diisocyanate, propylcyclohexane diisocyanate, methyldiethylcyclohexane 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 (4-isocyanatomethyl-1,8-octane diisocyanate). -isocyanatomethyl-1,8-octanediisocyanate, TIN), decane diisocyanate and triisocyanate, undecane diisocyanate and triisocyanate, dodecane diisocyanate and triisocyanate, hexamethylenediisocyanate (HDI), diisocyanatodicyclohexylmethane (HDI), 12 MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate / 2,4,4-trimethylhexamethylene diisocyanate (TMDI), norbornane diisocyanate (NBDI), xylylene diisocyanate (XDI), 1,4- or 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI), tetramethylxylylene diisocyanate, and dimers, trimers, derivatives and mixtures of two or more thereof. Suitable aliphatic polyisocyanates and alicyclic polyisocyanates that can be used in the present disclosure also include, for example, XDI-based polyisocyanates, H6XDI-based polyisocyanates, XDI isocyanurates, HDI-based polyisocyanates, H 12MDI-based polyisocyanates, HDI isocyanurates, and mixtures of two or more thereof.

[0035] Examples of some commercial products of aliphatic-based components useful in the present disclosure include, for example, TAKENATE available from Mitsui Chemicals, Inc. TM D-110N and TAKENATE TM D-120N; Desmodur available from Covestro TM N 3200, Desmodur TM Quix 175 and Desmodur TM 2460M; and mixtures thereof.

[0036] Additional isocyanate-containing compounds suitable for use in the present disclosure include, but are not limited to, polyisocyanates of 4-methyl-cyclohexane 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.

[0037] Based on the weight of the isocyanate component, the amount of isocyanate monomers, prepolymers, polyisocyanates or their mixtures can be greater than 50 wt.%.Based on the weight of the isocyanate component, the amount of isocyanate monomers, prepolymers, polyisocyanates or their mixtures can be 50 wt.% to 99 wt.%.All mixtures and individual values ​​are included and disclosed.For example, based on the weight of the isocyanate component, the amount of isocyanate monomers, prepolymers, polyisocyanates or their mixtures can include: upper limit 99 wt.%, 95 wt.%, 90 wt.%, 85 wt.%, 80 wt.%, 75 wt.%, 70 wt.%, 65 wt.%, 60 wt.% or 55 wt.% to lower limit 50 wt.%, 55 wt.%, 60 wt.%, 65 wt.%, 70 wt.%, 75 wt.%, 80 wt.%, 85 wt.%, 90 wt.%, 95 wt.%. The isocyanate component may also comprise ethyl acetate.

[0038] Polyol components

[0039] The polyol component may include a polyol having a molecular weight greater than or equal to 8000 and a T gPolyester polyols having a temperature of less than 5°C. Suitable polyester polyols useful in the present invention include, but are not limited to, aliphatic polyester polyols; aromatic polyester polyols; copolymers of aliphatic polyester polyols and aromatic polyester polyols; polycarbonate polyols; polycaprolactone polyols; and mixtures thereof. These polyester polyols are the reaction product of a polyacid and a polyol; or the reaction of phosgene or carbonate monomers with a polyol; or are prepared by ring-opening polymerization of cyclic ester compounds.

[0040] Examples of suitable polybasic acids that can be used in the present invention include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and anhydride or ester-forming derivatives of these dicarboxylic acids; as well as 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 can be used alone or in combination of two or more.

[0041] According to the present disclosure, any known polyol can be used. Non-limiting examples of suitable polyols that can be used in the present disclosure include: diols such as ethylene glycol, propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, triethylene glycol, polycaprolactone diol, dimer glycol, bisphenol A and hydrogenated bisphenol A; Polyesters produced by the ring-opening polymerization of propylene glycol, butylene oxide, ε-caprolactone, 8-valerolactone, and β-methyl-δ-valerolactone; and polyethers produced by the addition polymerization of one or more monomers (including ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexene) in a conventional manner with the aid of one or more compounds containing two active hydrogen atoms as initiators (such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol); and mixtures thereof. These polyols may be used alone or in combination of two or more.

[0042] Based on the weight of the polyol component, the amount of the polyester polyol used in the polyol component can be more than 50 wt.%. Based on the wt.% of the polyol component, the amount of the polyester polyol used in the polyol component can be 50 to 70 wt.%. All internal individual values ​​and internal ranges are included. For example, based on the weight of the polyol component, the amount of the polyester polyol used in the polyol component can be 55 wt.% to 65 wt.%.

[0043] The polyol component can include an epoxy resin. Based on the weight of the polyol component, the epoxy resin can be included in an amount of 14% to 30% by dry weight. All individual values ​​and internal ranges are included and disclosed. For example, based on the weight of the polyol component, the epoxy resin can be included in an amount of 20% to 25% by dry weight.

[0044] The polyol component may comprise a phosphate polyol having the structure shown in Structure 2, wherein R' is selected from any organic group:

[0045] [Structure 2].

[0046] In addition to the side groups shown in structure (2), R 1 may or may not have one or more additional pendant -OH groups, and R 1 There may or may not be one or more additional side groups of structure (2). Any two or more -OH groups and one or more groups of structure (2) may or may not be attached to R 1 Each -OH group and each group of structure (2) can be connected to R 1 of individual atoms.

[0047] Characterization R 1 A convenient way to describe a compound is to have the following structure (3):

[0048] [Structure 3].

[0049] Among them, R 1 Same as in structure (2). The compound having structure (3) is referred to herein as a "precursor polyol".

[0050] Suitable precursor polyols may 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 may have a number average Mw of 4,000 g / mol or less, 2,000 g / mol or less, 1,200 g / mol or less, 900 g / mol or less, or 500 g / mol or less. Suitable precursor polyols may have a number average Mw of 200 g / mol to 4,000 g / mol, 400 g / mol to 2,000 g / mol, 400 g / mol to 1,200 g / mol, or 400 g / mol to 900 g / mol.

[0051] Suitable precursor polyols may be alkyl higher polyols, monosaccharides, disaccharides and compounds having the following structure (4):

[0052] [Structure 4].

[0053] Among them, R 2 、R 3 、R 4 and R 5 Each is independently any organic group; n1, n2 and n3 are each independently an integer from 0 to 10. In addition to the side groups shown in structure (4), R 2 It should also be understood that any two or more side groups may or may not be attached to R 2 In some embodiments, there are mixtures of compounds having structure (4), wherein the compounds of structure (4) differ from one another in the value of one or more of n1, n2, and n3. Such mixtures are described herein by stating a non-integer value for a parameter n1, n2, or n3, where the non-integer value represents a number average value for that parameter. When it is desired to estimate the molecular weight of such a mixture, the number average molecular weight is used.

[0054] In the precursor polyol having structure (4), each side group can be attached to R 2 In the precursor polyol having structure (4), R 3 、R 4 and R 5 One or more of may be a hydrocarbon group having 1 C to 4 C, 2 C to 3 C, or 3 C. In the precursor polyol having structure (4), R 3 、R 4 or R 5 One or more of R may be an alkyl group, which may be linear or branched or a combination thereof; 3 、R4 or R 5 One or more of them may be a linear or branched alkyl group; and R 3 、R 4 or R 5 One or more of R may be a branched alkyl group. 3 、R 4 or R 5 can be identical to each other.

[0055] In the precursor polyol having structure (4), one or more of n1, n2, and n3 may be 0 to 8. In the precursor polyol having structure (4), one or more of n1, n2, and n3 may be 1 or greater. In the precursor polyol having structure (4), one or more of n1, n2, and n3 may be 6 or less. In the precursor polyol having structure (4), n1, n2, and n3 may be the same.

[0056] The precursor polyol group having structure (4) may be one in which R 2 、R 3 、R 4 and R 5 Each of the compounds is an alkyl group; such precursor polyols are referred to herein as alkoxylated alkyl triols. In the triol, when at least one of n1, n2, and n3 is 1 or greater and R 2 With the following structure (5):

[0057] [Structure 5].

[0058] This triol is referred to herein as alkoxylated glycerol. In the alkoxylated triol, when R 3 、R 4 and R 5 When each is a branched alkyl group having exactly 3 C, the alkoxylated triol is referred to herein as a propoxylated triol. 2 The propoxylated triol having structure (5) is referred to herein as propoxylated glycerol.

[0059] Among the precursor polyols as the alkyl higher polyols, there may be mentioned compounds having 10 C or less carbon atoms; compounds having 6 C or less carbon atoms; compounds having 3 or less carbon atoms; or glycerol.

[0060] The precursor polyol can be an alkyl higher polyol and a compound having structure (4). It should be noted that if n1 is equal to (=) n2=n3=0 and if R 2 is an alkyl group or an alkyl group having a hydroxyl group, then the compound having structure (4) is an alkyl higher polyol.

[0061] The precursor polyol group can be alkyl triols and alkoxylated alkyl triols. Among these compounds, there are glycerol and alkoxylated glycerols. Among the alkoxylated glycerols, there is propoxylated glycerol.

[0062] The phosphate ester compound may be a reaction product of reactants comprising a precursor polyol and a phosphoric acid-type acid, wherein the resulting phosphate ester compound has a chemical structure of structure (2).

[0063] The amounts of phosphoric acid and precursor polyol are selected to determine the ratio of Mp:Mx as follows: hy = number of hydroxyl groups per molecule of precursor polyol; N x =M hy -2;M x = (number of moles of precursor polyol) x (N x ); and M p = the number of moles of phosphorus atoms contained in phosphoric acid.

[0064] Typically, the ratio of Mp:Mx is 0.1:1 or higher, 0.2:1 or higher, 0.5:1 or higher, or 0.75:1 or higher. The ratio of Mp:Mx may be 1.1:1 or lower.

[0065] Typically, the weight ratio of phosphoric acid to precursor polyol is 0.005:1 or higher, 0.01:1 or higher, or 0.02:1 or higher. The weight ratio of phosphoric acid to precursor polyol can be 0.3:1 or lower, or 0.2:1 or lower, or 0.12:1 or lower.

[0066] Phosphoric acid may contain polyphosphoric acid. Typically, the amount of polyphosphoric acid in the phosphoric acid is 75 wt% or greater, 80 wt% or greater, or 90 wt% or greater, based on the weight of the phosphoric acid. Polyphosphoric acid is available in various grades; each grade is characterized by a percentage. To determine the grade, first consider pure monomeric orthophosphoric acid, where the phosphorus pentoxide content is assumed to be 72.4%. Any grade of polyphosphoric acid can also be analyzed to determine the number of moles of phosphorus pentoxide, designated "Nppo," contained in one mole of polyphosphoric acid (designated "Fppa" by formula weight). The phosphorus pentoxide percentage ("PCppo") is given by PCppo = (Nppo x 142) / Fppa, expressed as a percentage. The grade of the polyphosphoric acid is then expressed as a ratio expressed as a percentage: Grade = PCppo / 72.4.

[0067] The polyphosphoric acid used may have a grade of 100% or more, or 110% or more.The polyphosphoric acid used may have a grade of 150% or less, or 125% or less.

[0068] 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.

[0069] Based on the weight of the solvent-based laminating adhesive, the phosphate ester may be included in an amount of 0.3% to 2% by dry weight. All internal individual values ​​and internal ranges are inclusive. For example, based on the weight of the solvent-based laminating adhesive, the phosphate ester may be included in an amount of 0.5% to 1% by dry weight. In contrast to the polyol component, the phosphate ester may also be included in the isocyanate component.

[0070] The phosphate ester can have an NCO% less than or equal to 14. The phosphate ester can have an NCO% from 12 to 14. All internal individual values ​​and internal ranges are disclosed and included. For example, the phosphate ester can have an NCO% from 12.5 to 13.5.

[0071] Formation and use of adhesive compositions

[0072] It is contemplated that two components will be used in the present disclosure: an isocyanate component and a polyol component. It is also contemplated that the isocyanate component and the polyol component of the disclosed adhesive composition can be prepared separately and, if desired, stored until the adhesive composition is needed. The method for preparing the adhesive composition comprises mixing the above-described isocyanate and polyol components to form a curable adhesive composition. In some embodiments, both the isocyanate component and the polyol component are liquid at 25°C. When the adhesive composition is to be used, the isocyanate component and the polyol component are contacted with each other and typically mixed together in a stoichiometric ratio (NCO / OH) of 1 to 2.5. It is contemplated that when the two components come into contact, a curing reaction will begin, wherein the isocyanate groups react with the hydroxyl groups to form a urethane link. The adhesive composition formed by contacting the two components may be referred to as a "curable mixture."

[0073] In order to form the adhesive composition, in the process of forming the adhesive composition and with adhesive being applied to base material, can at any appropriate time (for example before the application process, during or as the result of the application process) carry out the mixing of two components.All steps can be carried out under environment, room temperature conditions.As required, heating or cooling can be used.Mixing can use suitable conventional mixer (as using electric, pneumatic or other power mechanical mixer) to carry out.

[0074] The method for preparing the solvent-based adhesive composition of the present disclosure, for example, includes the following steps: (1) providing an isocyanate component; (2) providing a polyol component; (3) mixing the two components to form a resin mixture; (4) diluting the resin mixture in a solvent to form a diluted resin mixture having an applied 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 (5) after applying the composition to a substrate and before curing the composition, removing the solvent from the composition to form the adhesive composition.

[0075] Also disclosed herein is a method for forming a laminate using an adhesive composition of the present disclosure. The adhesive composition, such as the adhesive composition discussed above, can be in a liquid state at 25°C. Even if the composition is solid at 25°C, the composition can be heated as needed to convert the composition into a liquid state. A solvent is added to the mixed adhesive composition until the desired solids content is reached. A solids content of 25% or greater can be used.

[0076] Adhesive compositions of the present disclosure are used to bond substrates together; and the adhesive compositions can be used on a variety of single suitable substrates or multiple suitable substrates. The substrates can be similar materials or dissimilar materials. For example, the substrate can be selected from high, low or medium density plastics (e.g., selected from the following types of plastics: 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, particleboard, textiles, leather and metals (e.g., aluminum, iron and other non-ferrous metals), metallized plastics (e.g., metallized plastic films), etc.

[0077] The wet and dry bonding lamination of a plurality of substrate layers is possible.Can use conventional application technology (as rotogravure printing, flexographic printing, conventional or airless spraying, roller coating, brush coating, wire rod coating, scraper coating or coating method (as curtain coating, flow coating, clock coating, pan coating and dip coating method)) adhesive composition is applied on the required substrate.Can carry out on the whole surface of substrate or on the part of substrate surface with adhesive composition coating substrate, for example, carry out along the edge or in intermittent position.In case be applied on the substrate, as by applying heat and air stream or be used to remove some other applicable conventional methods of all residual solvents substantially present in the adhesive composition, with the adhesive composition drying.

[0078] The laminate comprising a solvent-based adhesive composition of the present disclosure can be formed by applying an adhesive to at least one of two different substrates and combining the substrates together so that the adhesive is arranged between the surfaces of the two substrates; and then curing the adhesive to form a bond between the two substrates. The substrates may include, for example, two separate films; and each film may 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 thickness of the layer of curable adhesive composition mixture applied to the surface of the film is 1 micrometer (µm) to 5 µm. As used herein, "film" refers to any structure that is 0.5 mm or less in one dimension of the structure and 1 centimeter (cm) or greater in the other two dimensions of the structure.

[0079] The surface of another film is contacted with the layer of curable mixture to form an uncured laminate. The curable mixture is then cured or solidified. The uncured laminate can be subjected to pressure, for example, by nip rollers, which may or may not be heated. The uncured laminate can be heated to accelerate the curing reaction.

[0080] Suitable base materials for forming laminated structures include films, such as paper, weaving and nonwoven fabrics, polymer films, metal foil, metal-coated (metallized) polymer films and their combinations. Base materials are layered to form laminated structures, wherein one or more base materials are bonded together according to adhesive composition of the present disclosure. Film can optionally have the surface with ink-printed images thereon. Ink can contact with adhesive composition. Film can be polymer film, metal-coated polymer film or polymer film.

[0081] [Example]

[0082] The following examples are intended to further illustrate the present disclosure but should not be construed as limiting the scope of the claims. Unless otherwise specified, implicit from 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.

[0083] The various raw materials or ingredients used in the Inventive Examples (Inv. Ex.) and Comparative Examples (Comp-Ex.) are described below and are explained in Table I. All commercial samples were obtained from DOW Chemical.

[0084] Table 1: Raw materials

[0085]

[0086] Table 2: Two-component solvent-based laminating adhesive formulations

[0087] Note: The solid content of all samples in Table 2 is 30%, and all percentages are weight percentages based on the weight of the OH component.

[0088]

[0089] Table 3. Phosphate ester formulations containing NCO components

[0090]

[0091] General production method for OH components

[0092] As shown in Table 2, the OH component is a solution of a high molecular weight polyester polyol, epoxy resin, polycarbodiimide, and phosphate ester, all dissolved in an organic solvent. Before loading the raw materials into the reactor, the water content of all raw materials should be less than 500 ppm. Nitrogen is used throughout the stirring process to prevent moisture contamination. The solution system is maintained at room temperature at 50 rpm for 0.5 hours. Finally, the final product is placed in a well-sealed nitrogen-protected cylinder.

[0093] Production method of phosphate ester containing NCO component SR-F1

[0094] The phosphate-functional isocyanate compound of the present invention example was synthesized according to the formula listed in Table 3. Desmodur 2460M and Mor 88-138 were packed into a 1000 mL glass reactor, and the formula as shown in Table 3 was carefully mixed. After all the raw materials were fed, heating was started. When the temperature of the raw material mixture reached approximately 60°C, the rotating speed was increased to 50 rpm. Nitrogen was applied throughout the process to protect the system from moisture. When the reaction temperature reached approximately 80°C to 85°C, a cooling process was started and the reaction was kept at 80°C to 85°C for 2 hours. When the NCO value reached the design value, the reactor was cooled as quickly as possible. The system was cooled to 60°C to 70°C, ethyl acetate was packed into the glass reactor, and the rotating speed was kept at 50 rpm for 20 minutes. The final product was then packed into a well-sealed nitrogen protection cylinder.

[0095] Coating and lamination methods

[0096] Prior to lamination, nylon (NY) and polyvinyl chloride (PVC) films were stored at 50°C / 85% relative humidity for 5 days, simulating film storage conditions. Coating and lamination were performed in an SDC Labo-Combi 400 machine. Throughout the lamination process, the nip temperature was maintained at 70°C at a speed of 100 m / min. The coating weight was 4-4.5 g / m². 2The NY / foil was first laminated. The laminated NY / foil was then cured at 60°C / 85 RH for 7 days before testing. After curing, the laminated NY / foil was laminated with PVC according to the above process.

[0097] Table 4: Performance results:

[0098] test

[0099]

[0100] method

[0101] T-peel (90°) adhesion strength at 120°C (manual T-peel)

[0102] After curing, the laminated film was cut into 15 mm wide strips and subjected to a T-peel test using an Instron 5965 U 5974 machine at a crosshead speed of 250 mm / min. Three strips were tested in a warm oven at 120°C, and the average value was calculated. During the test, the tail of the strip was gently pulled with a finger to ensure that the tail remained at 90°C relative to the peel direction. The results are reported in N / 15 mm.

[0103] Deep Drawing Test (DDT)

[0104] The cured laminated film was cut into pieces of 8 cm × 12 cm in size and then placed on the platform of the SDCK-004A automatic deep drawing equipment for evaluation. The equipment was operated with specific parameters for deep drawing applications, which adjusted the air pressure to 0.5 MPa and maintained the punching speed of the die at 100 mm / min. For all laminates, the depth of the deep drawing test was set to 5 mm. The appearance of the laminates after deep drawing application was inspected, and the presence of bubbles, pits, delamination, and cracked substrates was noted. After stamping, the laminates were heated to 100°C in a warm oven for 1 hour, and the appearance was then inspected again.

[0105] Titration of easily oxidizable substances V (Na2S2O3 / ml)

[0106] The cured laminated film was cut into 3 cm × 0.3 cm pieces, then placed in a tightly sealed glass reactor with 200 ml of distilled water and heated at 70°C for 2 hours. 20 ml of the aqueous extract solution was heated to 100°C for 3 minutes, while 20 ml of potassium permanganate solution (0.002 mol / L) and 1 ml of sulfuric acid solution (0.1 mol / L) were added. The resulting solution was then quickly cooled to room temperature. 0.1 g of potassium iodide was added, and the solution was allowed to stand for 5 minutes. A 0.01 mol / L aqueous sodium thiosulfate solution was used for titration. Five drops of starch solution were added as an indicator. The volume of the aqueous sodium thiosulfate solution consumed before the mixed solution became transparent was recorded as V1. The same procedure was repeated using 20 ml of distilled water in place of the aqueous extract solution, and the volume of the aqueous sodium thiosulfate solution consumed (V1) was recorded as V2. The difference between V1 and V2 was measured as the readily oxidizable species released (V0) (Na2S2O3 / ml).

Claims

1. A two-component solvent-based laminating adhesive comprising: a. an isocyanate component comprising: i isocyanate monomers, polyisocyanates, isocyanate prepolymers, or a mixture of two or more of the isocyanate monomers, the polyisocyanates and the isocyanate prepolymers; ii. Ethyl acetate, b. A polyol component comprising: i. Molecular weight greater than or equal to 8000 and T g Polyester polyols with a temperature less than 5°C, ii. a phosphate polyol of the following structure, wherein R' is selected from any organic group: iii. Epoxy resin, in, The epoxy resin is contained in an amount of 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 ester is 0.3 to 2 dry weight percent, based on the weight of the solvent-based laminating adhesive.

2. The two-component solvent-based laminating adhesive according to claim 1, wherein The phosphate comprises the following structure, wherein R' is selected from any organic group 。 3. The two-component solvent-based laminating adhesive according to claim 1, further comprising an additional anti-hydrolysis agent, such as an azopyridine or a carbodiimide.

4. The two-component solvent-based laminating adhesive according to claim 1, further comprising an antioxidant.

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

6. The two-component solvent-based laminating adhesive according to claim 1, which does not contain polyether polyol.

7. The two-component solvent-based laminating adhesive according to claim 1, which does not contain novolac epoxy resin.

8. The two-component solvent-borne laminating adhesive of claim 1 , free of highly reactive amine-initiated polyols.

9. The two-component solvent-based laminating adhesive according to claim 1, wherein: V0 was determined as described in the instructions and ranged from 0.05 Na2S2O3 / ml to 1.70 Na2S2O3 / ml.

10. The two-component solvent-based laminating adhesive according to claim 1, wherein V0, determined as described in the instructions, ranged from 0.08 Na2S2O3 / ml to 0.20 Na2S2O3 / ml.

11. The two-component solvent-based laminating adhesive according to claim 1, wherein: The phosphate ester has an NCO % less than or equal to 14.

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

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

Images