Crosslinkable water-borne adhesive composition

Abstract

The present disclosure provides a composition. In an embodiment, the composition includes (A) a first polymer dispersion, a second polymer dispersion (B), and a crosslinking agent (C). The first polymer dispersion (A) includes a crosslinkable acrylic-based polymer comprising (i) at least two C1-C20 alkyl (meth)acrylate monomers, (ii) a monomer having an acid group, and (iii) an ethylenically unsaturated compound having at least one keto group or at least one aldehyde group. The second polymer dispersion (B) includes a non-crosslinkable acrylic polymer comprising a C1-C20 alkyl (meth)acrylate monomer. The composition also includes (C) the crosslinking agent.

Description

CROSSLINKABLE WATER-BORNE ADHESIVE COMPOSITIONBACKGROUND

[0001] The social and environmental drive for sustainable packaging is pushing the packaging industry toward recyclable, re-useable, and compostable packaging. Flexible packaging, and flexible food packaging in particular, is typically constructed from multilayer laminates. Many laminates for flexible food packaging require polyurethane-based adhesive compositions in order to obtain high heat resistance and / or high chemical resistance. Polyurethane-based adhesive compositions have several drawbacks. Polyurethane-based adhesive compositions are typically two-component adhesive systems which historically suffer from limited pot life. Polyurethane- based adhesive compositions are problematic due to the toxicity concern of the free isocyanate monomers (present in the adhesive composition) during processing and handling, and the toxicity concern of the primary aromatic amine (generated from the free aromatic isocyanate monomer) in the cured laminating adhesive, which cause the environmental, health, and safety risks. The presence of the polyurethane-based adhesive composition in the polyolefin films- based flexible packaging makes the entire polyolefin packaging material non-recyclable.

[0002] Water-borne acrylic-based adhesive compositions have been investigated as a possible alternative to polyurethane-based adhesive compositions in flexible food packaging. However, water-borne acrylic-based adhesive compositions have the disadvantages of poor heat resistance, poor water resistance, poor chemical or food product resistance, poor resistance to sterilization procedures and / or poor resistance to pasteurization procedures— properties that are required in many flexible packaging for food applications.

[0003] A need exists for a water-borne adhesive composition with sufficient heat resistance and food product resistance to withstand sterilization procedures and / or pasteurization procedures enabling use in flexible packaging for food, the water-borne adhesive composition also being free of isocyanate to enable the flexible packaging to have low, or no, toxicity risk and to be mechanically recyclable.SUMMARY

[0004] The present disclosure provides a composition. In an embodiment, the composition includes (A) a first polymer dispersion. The first polymer dispersion (A) includes a crosslinkableacrylic-based polymer comprising (i) at least two C1-C20 alkyl (meth)acrylate monomers, (ii) a monomer having an acid group, and (iii) an ethylenica lly unsaturated compound having at least one keto group or at least one aldehyde group. The composition also includes (B) a second polymer dispersion. The second polymer dispersion (B) includes a non-crosslinkable acrylic polymer comprising a C1-C20 alkyl (meth)acrylate monomer. The composition also includes (C) a crosslinking agent.

[0005] The present disclosure provides a laminate. In an embodiment, the laminate includes a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate. The adhesive layer includes an adhesive composition comprising (A) a crosslinkable acrylic-based polymer comprising (i) at least two C1-C20 alkyl (meth)acrylate monomers, (ii) a monomer having an acid group, and (iii) an ethylen ica I ly unsaturated compound having at least one keto group or at least one aldehyde group. The adhesive composition for the adhesive layer also includes (B) a non-crosslinkable acrylic polymer comprising a C1-C20 alkyl (meth)acrylate monomer. The adhesive composition for the adhesive layer also includes (C) a crosslinking agent.DEFINITIONS

[0006] Any reference to the PeriodicTable of Elements is that as published byCRC Press, Inc., 1990- 1991. Reference to a group of elements in this table is by the new notation for numbering groups.

[0007] For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference in their entirety (or its equivalent US version is so incorporated by reference) especially with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and general knowledge in the art.

[0008] The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., the range 1-7 above includes subranges of from 1 to 2; from 2 to 6; from 5 to 7; from 3 to 7; from 5 to 6; etc.).

[0009] Unless stated to the contrary, implicit from the context, or customary in the art, all partsand percents are based on weight and all test methods are current as of the filing date of this disclosure.

[0010] An "acrylic-based monomer," as used herein, is a monomer containing the Structure (I) below:Structure (I)wherein Ri is a hydroxyl group or a Ci-Cis alkyl group and R? is H or CH3. Acrylic-based monomers include acrylic acid, methacrylic acid, acrylates, and methacrylates.

[0011] The terms "blend" or "polymer blend," as used herein, is a blend of two or more polymers. Such a blend may or may not be miscible (not phase separated at molecular level). Such a blend may or may not be phase separated. Such a blend may or may not contain one or more domain configurations, as determined from transmission electron spectroscopy, light scattering, x-ray scattering, and other methods known in the art.

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

[0013] The terms "comprising," "including," "having" and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any succeeding recitation any other component, step, or procedure, excepting those that are not essential to operability. The term "consisting of" excludes any component, step, or procedure not specifically delineated or listed. The term "or," unless stated otherwise, refers to the listed members individually as well as in any combination. Use of the singular includes use of the plural and vice versa.

[0014] An "ethylene-based polymer" is a polymer that contains more than 50 weight percent (wt%)polymerized ethylene monomer (based on the total amount of polymerizable monomers) and, optionally, may contain at least one comonomer. Ethylene-based polymer includes ethylene homopolymer, and ethylene copolymer (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably.

[0015] An "olefin-based polymer" or "polyolefin" is a polymer that contains more than 50 weight percent polymerized olefin monomer (based on total amount of polymerizable monomers), and optionally, may contain at least one comonomer. A nonlimiting example of an olefin-based polymer is ethylene-based polymer.

[0016] A "polymer" is a compound prepared by polymerizing monomers, whether of the same or a different type, that in polymerized form provide the multiple and / or repeating "units" or "mer units" that make up a polymer. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term copolymer, usually employed to refer to polymers prepared from at least two types of monomers. It also embraces all forms of copolymer, e.g., random, block, etc. The terms "ethylene / a-olefin polymer" and "propylene / a-olefin polymer" are indicative of copolymeras described above prepared from polymerizing ethylene or propylene respectively and one or more additional, polymerizable a- olefin monomer. It is noted that although a polymer is often referred to as being "made of" one or more specified monomers, "based on" a specified monomer or monomer type, "containing" a specified monomer content, or the like, in this context the term "monomer" is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein are referred to as being based on "units" that are the polymerized form of a corresponding monomer.TEST METHODS

[0017] Density was measured in accordance with ASTM D792, Method B. The result is recorded in grams per cubic centimeter (g / cc).

[0018] Green bond strength was measured just after lamination of the first and second films with the adhesive same as T-peel test described as following, the average of mean value of T-peel bondstrength was reported in grams per inch (g / 2.54cm).

[0019] Pot life. The pot life of two-component ("2K") waterborne adhesive was assessed by measuring the Zahn Cup viscosity versus time by using Zahn Cup 2 (Signature). The pot life was defined as the time elapsed after mixing of the two components when the viscosity of the mixture was twice the initial viscosity of the of the mixture when immediately prepared. For a one- component ("IK") waterborne adhesive, the pot life is not defined because the performance and usability of the one-component adhesive are maintained over a much longer period than for a two-component adhesive. Instead, the shelf life is used to measure the long-term stability of the IK waterborne adhesive.

[0020] Shelf life. Shelf life of the one-component ("IK") waterborne adhesive was assessed by measuring the Brookfield viscosity of the adhesive at room temperature (23°C) by using Brookfield viscometer DIV I with spindle #1. The shelf life was defined as the time that the viscosity exceeded 110% of initial viscosity of the formulated adhesive. For a two-component ("2K") waterborne adhesive, the shelf life is defined to the be the same as the pot life.

[0021] T-peel bond strength was measured on a 2.54 cm wide strip at a rate of 25.4 cm / min and pulled on a Thwing Albert™ QC-3A peel tester equipped with a 50N loading cell at a rate of 25.4 cm / min. Three strips were tested for each laminate and high and mean strength were recorded together along with the failure mode. In case of film tear and film stretch, the high value of T-peel bond strength was reported and in other failure modes the average of mean value of T- peel bond strength was reported in grams per inch (g / 2.54cm). Typical failure modes include:• AF- Adhesive failure (adhesive with primary after peel)• AT- Adhesive transfer (adhesive with secondary after peel)• AS- Adhesive split (cohesive failure of adhesive)• FT- Film tear (destruct bond)• FS- Film stretch (destruct bond)

[0022] Viscosity. The Brookfield viscosity of the waterborne adhesive was measured at room temperature (23°C) by using a Brookfield viscometer DIV I with spindle #1, with results reported in mPa.s.DETAILED DESCRIPTION

[0023] The present disclosure provides a composition. In an embodiment, the composition includes (A) a first polymer dispersion, (B) a second polymer dispersion, and (C) a crosslinking agent. The first polymer dispersion (A) includes a crosslinkable acrylic-based polymer composed of (i) at least two C1-C20 alkyl (meth)acrylate monomers, (ii) a monomer having an acid group, and (iii) an ethylenica lly unsaturated compound having at least one keto functional group or at least one aldehyde functional group. The composition also includes the second polymer dispersion (B). The second polymer dispersion (B) is composed of a non-crosslinkable acrylic polymer composed of one or more C1-C20 alkyl (meth)acrylate monomer(s). The composition also includes (C) the crosslinking agent.

[0024] The composition includes the first polymer dispersion (A) and the second polymer dispersion (B). The term "polymer dispersion" is a composition wherein water is the continuous phase, i.e., a composition having an aqueous medium. The polymer dispersion includes one or more acrylic-based monomers, a surfactant, and water to the exclusion of an ethylene-based polymer. The surfactant acts as an emulsifier and enables droplets of the acrylic-based monomer, which is hydrophobic, to form throughout the aqueous medium. An initiator is then introduced into the emulsified mixture. The initiator initiates the polymerization of acrylic-based monomer(s) dispersed throughout the aqueous medium until all, or substantially all, of the acrylic-based monomer(s) is polymerized. The end result is a polymer dispersion (an acrylic dispersion or emulsion) composed of a dispersion of acrylic-based polymer particles in the aqueous medium, the acrylic-based polymer particles composed of one or more acrylic-based monomer subunits to the exclusion of ethylene-based polymer.

[0025] The polymer dispersion (A) includes the crosslinkable acrylic-based polymer. The crosslinkable acrylic-based polymer includes at least two C1-C20 alkyl (meth)acrylate monomers. Nonlimiting examples of suitable C1-C20 alkyl (meth)acrylate monomers include butyl acrylate (BA), ethylhexyl acrylate (2-EHA), ethyl acrylate (EA), methyl acrylate (MA), butyl methyacrylate (BMA), octyl acrylate, isooctyl acrylate, decyl acrylate, isodecyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate (MMA), isobutyl methacrylate, octyl methacrylate, isooctyl methacrylate, decyl methacrylate, isodecyl methacrylate, lauryl methacrylate,pentadecyl methacrylate, stearyl methacrylate, n-butyl methacrylate, C12 to Cis alkyl methacrylates, and combinations thereof. In an embodiment, the at least two C1-C20 alkyl (meth)acrylate monomers are selected from at least two Ci-Cg (meth)acrylates including methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), ethylhexyl acrylate (2-EHA), octyl acrylate, methyl methacrylate (MMA), and octyl methacrylate. The total concentration of the C1-C20 alkyl (meth)acrylate used in the polymer dispersion (A) crosslinkable acrylic-based polymer is from 55 weight percent (wt %) to 99.8 wt %, or from 80 wt % to 99 wt %, or from 85 wt % to 98 wt % based on the weight percentage of the total monomer units comprising the crosslinkable acrylicbased polymer.

[0026] The crosslinkable acrylic-based polymer of the first polymer dispersion (A) includes a monomer having an acid group ("acid monomer"). The acid monomer is an ethylenically unsaturated monomer having at least one acid group, and also anhydrides and salts thereof. The acid monomer may include alpha, beta-monoethylenically unsaturated monocarboxylic and dicarboxylic acids, monoesters of alpha, beta-monoethylenically unsaturated dicarboxylic acids, the anhydrides of the aforesaid alpha, beta-monoethylenically unsaturated carboxylic acids, and also ethylenically unsaturated sulfonic acids, phosphonic acids or dihydrogenphosphates and their water-soluble salts, as for example their alkali metal salts. Nonlimiting examples of suitable acid monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylaceticacid, vinyllactic acid, and combinations thereof. The total concentration of the acid monomer in the polymer dispersion (A) crosslinkable acrylic-based polymer is from 15 weight percent (wt %) to 0.1 wt %, or from 10 wt % to 0.5 wt %, or from 8 wt % to 1 wt % based on the weight percentage of the total monomer units comprising the crosslinkable acrylicbased polymer.

[0027] In an embodiment, the acid monomer is acrylic acid.

[0028] The crosslinkable acrylic-based polymer of the first polymer dispersion (A) includes at least one ethylenically unsaturated compound having a keto group or an aldehyde group. Two or more ethylenically unsaturated compounds having a keto group or aldehyde group may be used in the crosslinkable acrylic-based polymer of the first polymer dispersion (A). Nonlimiting examples of suitable ethylenically unsaturated compounds having a keto group or aldehydegroup include acetoacetyl (meth)acrylate, acetoacetoxyethyl (meth)acrylate, diacetone acrylamide (DAAM), acrolein, methacrolein, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, vinyl amyl ketone, 2-[(2-methyl-l-oxo-2-propenyl)oxy]ethyl 3-oxobutanoate. The total concentration of the ethylenically unsaturated compounds having a keto group or aldehyde group used in the polymer dispersion (A) crosslinkable acrylic-based polymer is from 8 weight percent (wt %) to 0.1 wt %, or from 6 wt % to 0.2 wt %, or from 5 wt % to 0.5 wt % based on the weight percentage of the total monomer units comprising the crosslinkable acrylic-based polymer.

[0029] In an embodiment, the crosslinkable acrylic-based polymer of the first polymer dispersion is void of styrene and the ethylenically unsaturated compound having a keto group is diacetone acrylamide ("DAAM").

[0030] In an embodiment, the crosslinkable acrylic-based polymer of the first polymer dispersion (A) may include one or more optional other monomer component(s). Nonlimiting examples of suitable other monomer components include vinylaromatic monomer such as styrene, a-methylstyrene, vinyltoluene, 4-n-butylstyrene, and 4-tert-butylstyrene, a vinyl ester of an aliphatic C2 - C10 carboxylic acid such as vinyl acetate and vinyl propionate; and mixtures thereof. Additional other monomer component(s) include a monoethylenically unsaturated nitrile such as acrylonitrile, methacrylonitrile, and mixtures thereof. Additional other monomer component(s) include unsaturated monomers such as an amide of a monoethylenically unsaturated C3 - Cg monocarboxylic acid such as acrylamide and methacrylamide; a hydroxyl -C4 alkyl ester of a monoethylenically unsaturated C3 - C8 monocarboxylic acid, more particularly a C2 - C4 hydroxyalkyl acrylate and methacrylate such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate; and mixtures thereof.

[0031] The composition includes the second polymer dispersion (B). The second polymer dispersion (B) includes a non-crosslinkable acrylic polymer. A "non-crosslinkable acrylic polymer," as used herein, is a (meth)acrylate void (or substantially void) of a keto group and / or void (or substantially void) of an aldehyde group. The term "substantially void" is an amount fromgreater than 0 wt% to less than 0.05 wt % of keto group and / or aldehyde group due to impurities in the monomers and / or side reactions, based on total dry weight of the second polymer dispersion (B).

[0032] The non-crosslinkable acrylic polymer includes one or more C1-C20 alkyl (meth)acrylate monomers. Nonlimiting examples of suitable (meth)acrylate monomers include butyl acrylate (BA), ethylhexyl acrylate (2-EHA), ethyl acrylate (EA), methyl acrylate (MA), butyl methyacrylate (BMA), octyl acrylate, isooctyl acrylate, decyl acrylate, isodecyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate (MMA), isobutyl methacrylate, octyl methacrylate, isooctyl methacrylate, decyl methacrylate, isodecyl methacrylate, lauryl methacrylate, pentadecyl methacrylate, stearyl methacrylate, n-butyl methacrylate, C12 to Ci8 alkyl methacrylates, and combinations thereof. In an embodiment, the C1-C20 alkyl (meth)acrylate monomer is selected from Ci-Cs (meth)acrylates including methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), ethylhexyl acrylate (2-EHA), octyl acrylate, methyl methacrylate (MMA), and octyl methacrylate.

[0033] The non-crosslinkable acrylic-based polymer of the second polymer dispersion (B) includes a monomer having an acid group ("acid monomer"). Nonlimiting examples of suitable acid monomer include acrylic acid, methacrylic acid, and combinations thereof. The total concentration of the acid monomer present in the polymer dispersion (B) non-crosslinkable acrylic-based polymer is from 15 weight percent (wt %) to 0.1 wt %, or from 12 wt % to 5 wt %, or from 10 wt % to 6 wt % based on the weight percentage of the total monomer units comprising the polymer.

[0034] In an embodiment, the non-crosslinkable acrylic polymer of dispersion (B) is composed of, or consists of, (i) a C1-C20 alkyl (meth)acrylate monomer and (ii) an acid monomer. The non- crosslinkable acrylic polymer is void of ethylenically unsaturated compound having a keto group or an aldehyde group and / or is void of DAAM. The non-crosslinkable acrylic polymer is also void of styrene.

[0035] In an embodiment, the non-crosslinkable acrylic-based polymer of the second polymer dispersion (B) may include one or more optional other monomer component(s). Nonlimiting examples of suitable other monomers include a vinylaromatic monomer such as styrene, a-methylstyrene, vinyltoluene, 4-n-butylstyrene, and 4-tert-butylstyrene, a vinyl ester of an aliphatic C2 - C10 carboxylic acid such as vinyl acetate and vinyl propionate; and mixtures thereof. Additional other monomer component(s) include monoethylenically unsaturated nitrile such as acrylonitrile, methacrylonitrile, and mixtures thereof. Additional other monomer component(s) include unsaturated monomers an amide of a monoethylenically unsaturated C3 - Cs monocarboxylic acid such as acrylamide and methacrylamide; a hydroxy-C? - C4 alkyl ester of a monoethylenically unsaturated C3 - Cs monocarboxylic acid, more particularly a C2 - C4 hydroxyalkyl acrylate and methacrylate such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate; and mixtures thereof. In a further embodiment, the one or more other monomer component(s) is present, and the other monomer component is selected from the foregoing list, and (iii) the other monomer component is different from Component (A) and different from Component (B).

[0036] The composition includes the water-soluble crosslinking agent (C). The water-soluble crosslinking agent has at least two functional groups, or from two functional groups to five functional groups, which enter into a crosslinking reaction with the keto group or the aldehyde group of the crosslinkable acrylic polymer present in the first polymer dispersion (A). Nonlimiting examples of suitable functional groups for crosslinking agent (C) include hydrazide groups, hydrazine groups, oxime ether groups, hydroxylamine groups, O-substituted hydroxylamine groups, and combinations thereof.

[0037] In an embodiment, the functional groups of water-soluble crosslinking agent (C) are hydrazide groups. Nonlimiting examples of suitable compounds for the crosslinking agent (C) include compounds having a hydrazide group such as dicarboxylic dihydrazides having from 1 to 10 carbon atoms or carbohydrazide, oxalic dihydrazide, malonic dihydrazide, succinic dihydrazide, glutaric dihydrazide, adipic dihydrazide, sebacic dihydrazide, maleic dihydrazide, fumaric dihydrazide, itaconic dihydrazide, isophthalic dihydrazide, cyclohexane dicarboxylic acid bis-hydrazide, fumaric acid dihydrazide, tartaric acid dihydrazide, and combinations thereof.

[0038] In an embodiment, the water-soluble crosslinking agent is selected from adipic aciddihydrazide (ADH), sebacic dihydrazide and isophthalic dihydrazide. In a further embodiment, the water-soluble crosslinking agent is adipic acid dihydrazide (ADH). The amount of the water- soluble crosslinking agent (C) is selected such that the molar ratio of the functional groups which enter into a crosslinking reaction with the keto group / aldehyde group of the first polymer dispersion (A) is from 1:10 to 2:1, or from 1:5 to 2:1, or from 1:2 to 2:1.

[0039] The first polymer dispersion (A) and / or the second polymer dispersion (B) may include a surfactant. Nonlimiting examples of suitable surfactants include cationic surfactants, anionic surfactants, zwitterionic surfactants, non-ionic surfactants, and combinations thereof. Examples of anionic surfactants include, but are not limited to, sulfonates, carboxylates, and phosphates. Examples of cationic surfactants include, but are not limited to, quaternary amines. Examples of non-ionic surfactants include, but are not limited to, block copolymers containing ethylene oxide and silicone surfactants, such as ethoxylated alcohol, ethoxylated fatty acid, sorbitan derivative, lanolin derivative, ethoxylated nonyl phenol, or alkoxylated polysiloxane. Commercially- available examples of suitable surfactants include, but are not limited to, surfactants sold under the trade names TERGITOL™ and DOWFAX™ by The Dow Chemical Company, such as TERGITOL™ 15-S-9 and DOWFAX™ 2A1, and products sold under the DISPONIL trade name by BASF SE, such as DISPONIL FES 77 IS and DISPONIL FES 993.

[0040] The first polymer dispersion (A) and / or the second polymer dispersion (B) are made from free radical polymerization initiated by an initiator. The initiator can be either a thermal initiator or a redox system initiator. Examples of the thermal initiator include, but are not limited to, ammonium persulfate, sodium persulfate, and potassium persulfate. When the initiator is a redox system initiator, the reducing agent can be, for example, an ascorbic acid, a sulfoxylate, or an erythorbic acid, while the oxidating agent can be, for example, a peroxide or a persulfate.D. Additives

[0041] The first polymer dispersion (A) and / or the second polymer dispersion (B) may include one or more optional additives. When the additive is present, nonlimiting examples of suitable additives include thickener, defoamer, wetting agent, mechanical stabilizer, pigment, filler, freeze-thaw agent, neutralizing agent, plasticizer, adhesion promoter, and combinations thereof.

[0042] In an embodiment, the composition includes from greater than 0 wt% to 5 wt% thickener, based on the total dry weight of the composition. Suitable thickeners include, but are not limited to, ACRYSOL™, UCAR™ and CELLOSIZE™ which are commercially available from The Dow Chemical Company, Midland, Michigan.

[0043] In an embodiment, the composition includes from greater than 0 wt% to 2 wt% of a neutralizing agent, based on the total dry weight of the composition. The neutralizing agent is used to control pH and provide stability to the formulated adhesive composition. Suitable neutralizing agents include, but are not limited to, aqueous ammonia, aqueous amines, and other aqueous inorganic salts.

[0044] In an embodiment, the first polymer dispersion (A) of the composition includes a crosslinkable acrylic-based polymer composed of ethyl acrylate, methyl methacrylate, acrylic acid, and diacetone acrylamide (DAAM), the second polymer dispersion (B) includes a non- crosslinkable acrylic polymer with a C1-C20 alkyl (meth)acrylate monomer, and the crosslinking agent (C) is adipic acid dihydrazide (ADH). The composition is void of styrene.

[0045] In an embodiment, the adhesive composition includes(A) the first polymer dispersion with from 60 wt% to 85%, or from 59.9 wt% to 84.9 wt%, or from 65 wt% to 80 wt% or from 70 wt% to 77 wt% of the crosslinkable acrylic-based polymer with (i) at least two C1-C20 alkyl (meth)acrylate monomers, (ii) a monomer having an acid group, and (iii) an ethylenica I ly unsaturated compound having at least one keto or aldehyde group;(B) the second polymer dispersion with from 15 wt% to 35 wt%, or from 17 wt% to 30 wt%, or from 18 wt% to 25 wt% of the non-crosslinkable acrylic polymer having a C1-C20 alkyl (meth)acrylate monomer; and(C) from 0.1 wt% to 5 wt%, or from 0.3 wt% to 3 wt%, or from 0.5 wt% to 2 wt% of the crosslinking agent, wherein weight percent is based on total dry weight of the composition.

[0046] In an embodiment, the composition includes(A) the first polymer dispersion with from 60 wt% to 85%, or from 59.9 wt% to 84.9 wt%, or from 65 wt% to 80 wt% or from 70 wt% to 77 wt% the crosslinkable acrylic-based polymer with monomers of ethyl acrylate, methyl methacrylate, acrylic acid, and from 1 wt% to 6 wt%, or from 1.9 wt% to 5 wt% DAAM;(B) the second polymer disperion with from 15 wt% to 35 wt%, or from 17 wt% to 30 wt%, or from 18 wt% to 25 wt% of the non-crosslinkable acrylic polymer having a C1-C20 alkyl (meth)acrylate monomer; and(C) from 0.1 wt% to 5 wt%, or from 0.3 wt% to 3 wt%, or from 0.5 wt% to 2 wt% of the crosslinking agent that is ADH, and the composition is void of styrene, wherein weight percent is based on total dry weight of the composition.F. Laminate

[0047] The present disclosure provides a laminate. The laminate includes a first substrate, a second substrate, and an adhesive composition between the first substrate and the second substrate. The adhesive composition (interchangeably referred to as an adhesive layer) is the present composition with the water removed, the adhesive composition formed from the first polymer dispersion (A), the second polymer dispersion (B) and the crosslinking agent (C) as disclosed herein. The water is removed from present composition to form the adhesive layer such that the adhesive layer is an adhesive composition composed of a crosslinkable acrylic-based polymer (formed from the first polymer dispersion (A)). The crosslinkable acrylic-based polymer includes: (i) at least two Ci- C20 alkyl (meth)acrylate monomers, (ii) a monomer having an acid group, and (iii) an ethyle nica I ly unsaturated compound having at least one keto group or at least one aldehyde group. The adhesive composition also includes the non-crosslinkable acrylic polymer of a C1-C20 alkyl (meth)acrylate monomer (formed from the second polymer dispersion (B)). The adhesive composition also includes (C) the crosslinking agent, forming the linkages in the crosslinkable acrylic-based polymer.

[0048] The laminate includes a first substrate and a second substrate. The first substrate and the second substrate may be the same or different. In an embodiment, the first substrate and the second substrate are the same, such that they have the identical compositions and identical structures. In an embodiment, the first substrate and the second substrate are compositionally distinct and / or structurally distinct from one another.

[0050] It is understood that the below description referring to a "substrate" refers to the first substrate and the second substrate, individually and / or collectively.

[0051] A nonlimiting example of a suitable substrate is a film. The film may be a monolayer film or a multilayer film. The multilayer film contains two layers, or more than two layers. For example, the multilayer film can have two, three, four, five, six, seven, eight, nine, ten, eleven, or more layers. In an embodiment, the multilayer film contains only two layers, or only three layers.

[0052] In an embodiment, the film is a monolayer film with one, and only one, layer.

[0053] In an embodiment, the film includes a layer containing a component selected from ethylene-based polymer, propylene-based polymer (PP), polyamide (such as nylon), polyester, ethylene vinyl alcohol (EVOH) copolymer, polyethylene terephthalate (PET), ethylene vinyl acrylate (EVA) copolymer, ethylene methyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene butyl acrylate copolymer, ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, an ionomer of ethylene acrylic acid, an ionomer of metharcylic acid, maleic anhydride grafted ethylenebased polymer, a polylactic acid (PLA), a polystyrene, a metal foil, a cellulose, cellophane, nonwoven fabric, and combinations thereof. A nonlimiting example of a suitable metal foil is aluminum foil. The film may also include metalized polyester (PET), metalized Polypropylene (PP). Each layer of a multilayer film may for formed from the same component, or from different components.

[0054] In an embodiment, the film includes a layer containing metal foil.

[0055] In an embodiment, the film is a monolayer film having a single layer that is an ethylenebased polymer layer. In a further embodiment, the film is a monolayer film having a single layer that is a polyethylene layer.

[0056] The substrate, and further the film, is a continuous structure with two opposing surfaces.

[0057] In an embodiment, the substrate (film) has a thickness from 5 pm more, or 10 pm, or 15 pm, or 20 pm, 25 pm, or 30 pm, or 40 pm, or 50 pm, or 100 pm, or 200 pm, or 300 pm, , or 400 pm, or 500 pm. In an embodiment, the substrate (film) has a thickness 500 pm or less, or 400 pm less, or 300 pm less.

[0058] In an embodiment, the first substrate is a film having a layer that is a metal foil layer; and the second substrate is a monolayer film having a single layer that is an ethylene-based polymer layer (such as linear low density polyethylene (LLDPE)) or a propylene-based polymer layer (such as polypropylene).

[0059] The first substrate may comprise two or more embodiments disclosed herein.

[0060] The second substrate may comprise two or more embodiments disclosed herein.

[0061] The present composition is applied onto the first substrate and then laminated it with the second substrate by contacting the adhesive layer, such as with a Nordmeccanica La bo Combi laminator, for example.

[0062] Nonlimiting examples of suitable application methods include brushing, pouring, spraying, coating, rolling, spreading, and injecting.

[0063] In an embodiment, the present composition is applied between the first substrate and the second substrate at a coat weight (dry) from 0.5 grams per square meter (g / m2) to 5.0 g / m2.

[0064] In an embodiment, the present composition is uniformly applied on the first substrate, or on the second substrate, or on both first and second substrates, the water is removed, or is otherwise evaporated, to form the adhesive composition, the adhesive composition forms the adhesive layer and then the adhesive layer is brought into contact with the second substrate. A "uniform application" is a layer of the present composition that is continuous (not intermittent) across a surface of the substrate, and of the same, or substantially the same, thickness across the surface of the substrate. In other words, a composition that is uniformly applied to a substrate directly contacts the substrate surface, and the composition is coextensive with the substrate surface.

[0065] The present adhesive composition and the first substrate are in direct contact with each other. The term "direct contact," or "directly contacts," as used herein, is a layer configuration whereby a substrate is located immediately adjacent to the present composition, or immediately adjacent to the adhesive layer, and no intervening layers, or no intervening structures, are present between the substrate and the present composition, or the adhesive layer. The present adhesive composition directly contacts the surface of the first substrate. The structure containing the first substrate and the present composition has the following Structure (D):First Substrate / Present Adhesive Composition Structure (D)

[0066] In an embodiment, the Structure (D) is dried to form an adhesive layer in direct contact with the first substrate. In a further embodiment, the Structure (D) is dried by passing it through an oven at a temperature sufficient to evaporate all, or substantially all, of the water from the present composition. Then, the adhesive layer is contacted with the second substrate through a lamination process to form a laminate. The first substrate is in direct contact with the adhesivelayer and the second substrate is in direct contact with the adhesive layer and the laminate has the following Structure (E):First Substrate / Adhesive Layer / Second Substrate Structure (E).

[0067] In an embodiment, the adhesive layer and the second substrate are in direct contact with each other. The adhesive layer directly contacts a surface of the second substrate.

[0068] The adhesive layer of Structure (E) is formed from curing or drying the present composition.

[0069] The laminate includes the first substrate in direct contact with the adhesive layer, and the second substrate in direct contact with the adhesive layer.

[0070] The present disclosure also provides an article containing, or otherwise formed from, the laminate. Nonlimiting examples of suitable articles include packages, bags, pouches, deep-drawn cans, and containers.

[0071] In an embodiment, the laminate contacts a comestible. A "comestible" is an edible food item.

[0072] In an embodiment, the laminate contacts a non-comestible. A "non-comestible" is industrial item.

[0073] The present composition is a crosslinked one-component ("IK") water-borne acrylic adhesive and can be used with polyolefin films / substrates to make laminates (such as food packaging) that are recyclable. Compared to conventional two-component polyurethane adhesive compositions, the present composition not only meets or exceeds the adhesion performance of two-component polyurethane adhesive compositions but does so without requiring in situ mixing and has no pot life concern as do two component adhesives.

[0074] The present composition is a one-component water-borne acrylic adhesive composition and contains no isocyanate and thereby avoids: (i) the risks associated with isocyanate monomer toxicity, (ii) primary aromatic amine toxicity, (iii) the pot-life limitations of conventional two- component polyurethane adhesive compositions, (iv) outgassing found in polyurethane adhesives which cause appearance issues due to isocyanate reaction moisture during curing. When the present composition is used with polyolefin substrates / films (such as polyethylene) to produce packaging, the packaging is mechanically recyclable.

[0075] It is known that acyl hydrazides such as ADH react with ketones and aldehydes to form hydrazone linkages. When a multi-functional hydrazide such as ADH reacts with polymerscontaining ketones or aldehydes, the resulting hydrazone linkages cause crosslinking of the polymers. Bounded by no particular theory, it is known that acrylic polymers which do not contain ketone functionality do not crosslink with ADH. It would therefore be expected that blending the present crosslinkable acrylic-based polymer with the present non-crosslinkable acrylic-based polymer would lead to poor laminating adhesive performance because the non-crosslinkable polymer would disrupt the full crosslinking of the adhesive / adhesive film layer. Applicant discovered the present composition that is a polymer blend of the crosslinkable acrylic-based polymer and the noncrosslinkable acrylic-based polymer (and crosslinking agent) unexpectedly has acceptable laminating adhesive performance for food packaging in particular.

[0076] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.EXAMPLES

[0077] Materials used in the comparative samples (CS) and inventive examples (IE) are provided in Table 1 below.

[0078] Table 1

[0079] A. Comparative Sample 1 (CS1)

[0080] A first polymer dispersion with an acrylic-based polymer composed of 85.9% EA / 10.1% MMA / 4.0% AA (based on total weight of the acrylic-based polymer) was prepared by the following procedure.

[0081] Using a 5L flask equipped with a mechanical stirrer, a charge of 546 g of deionized water was warmed to 96°C. Next, 23.8 g of 26.4 % concentration ammonium persulfate in water waspoured into the flask. Subsequently, 122.8 g of a polymer seed latex with a diameter of 100 nm at 43 % concentration in water was poured into the flask. Then, 8.7 g of 3.3 % concentration ammonia in water was poured into the flask.

[0082] Over a span of 180 minutes with a constant feed rate, a monomer emulsion feed made up of 74.4 g of acrylic acid (AA), 1603.1 g of ethyl acrylate (EA), 189.3 g of methyl methacrylate (MMA), 543 g of deionized water, and 7.72 g of 22 % concentration sodium dodecylbenzenesulfonate in water, was gradually dispensed into the flask. From the outset of the emulsion feed, 94.1 g of an ammonium peroxodisulfate (2.0 wt % concentration) solution in water was added at a constant rate over 180 minutes to form a reaction medium; and the reaction medium was maintained from 83 °C to 85 °C during the 180 minutes. In addition, at 140 minutes from the outset of the emulsion feed, 94.4 g of a sodium carbonate (3.0% concentration) solution in water was added starting at a rate of 1.05 g per min for 40 minutes. After 170 minutes of the feed period of the monomer emulsion had elapsed, the temperature of the reaction medium was allowed to rise to 88 °C to 90 °C and maintained at this temperature until 200 minutes from the outset of the monomer emulsion feed. After 180 minutes of the feed period of the monomer emulsion had elapsed, the addition rate of the sodium carbonate solution was increased to a rate of 2.62 g per min and maintained at this rate for 20 minutes. At 200 minutes from the outset of the monomer emulsion feed, the reaction medium was cooled to 75°C over 15 minutes.

[0083] When the temperature of the reaction medium was 75°C, a solution of iron (II) sulfate heptahydrate (0.01 g) in 8.2 g of water was added to the flask; and the following two mixtures were fed to the flask: the first mixture (mixl) was 30.4 g of a solution of 8.7 % concentration aqueous solution of tert-butyl hydroperoxide; and the second mixture (mix2) was 57.2 g of a 2.4 % concentration aqueous solution of sodium formaldehyde sulfoxylate. Mixl was fed to the flask over the span of 30 minutes; and mix2 was fed to the flask over the span of 30 minutes. During the addition of these two mixtures (mixl and mix2), the contents of the flask were cooled to 65 °C over the course of 30 minutes. The foregoing method yields a first polymer dispersion with 85.9% EA / 10.1% MMA / 4.0% AA, based on total dry weight of the first polymer dispersion.

[0084] The second polymer dispersion prepared in comparative sample 1 was N-CAP water-borne binder which does not contain any DAAM.

[0085] The one-component waterborne acrylic adhesive composition of CS1 was prepared by blending 57.5 g of the first polymer dispersion with 38.3 g of the second polymer dispersion, 1.0 g of Surfynol 420, 2.6 g of deionized water, 0.2 g of Foamaster MO 5090, and 0.5 g of TERGITOL™ 15-5-3 Surfactant. CS1 was pH 7.14, Brookfield viscosity 120 mPa.s, and 41.3% solids. No further formulation components were added to CS1.

[0086] CS1 first polymer dispersion 76 wt% (acrylic-based polymer: 85.9% EA / 10.1% MMA / 4.0% AA weight percent based on total weight of acrylic-based polymer); and second polymer dispersion 20 wt% (N-CAP water-borne binder), weight percent based on total dry weight of the final composition; andSurfynol 420 2.3 wt%, weight percent based on total dry weight of the final composition;Foamaster MO 5 090 0.5 wt%, weight percent based on total dry weight of the final composition; andTERGITOL™ 15-5-3 1.2 wt%, weight percent based on total dry weight of the final composition.

[0087] B. Aqueous Dispersion 1

[0088] A first polymer dispersion with a crosslinkable acrylic-based polymer composed of 85.9% ethyl acrylate (EA) / 8.2% methyl methacrylate (MMA) / 4.0% acrylic acid (AA) / 1.9% diacetone acrylamide (DAAM) (based on total dry weight of the crosslinkable acrylic-based polymer) was prepared by the following procedure.

[0089] Using a 5L flask equipped with a mechanical stirrer, a charge of 546 g of deionized water was warmed to 96°C. Next, 23.8 g of 26.4 % concentration ammonium persulfate in water was poured into the flask. Subsequently, 122.8 g of a polymer seed latex with a diameter of 100 nm at 43 % concentration in water was poured into the flask. Then, 8.7 g of 3.3 % concentration ammonia in water was poured into the flask.

[0090] Over a span of 180 minutes with a constant feed rate, a monomer emulsion feed made of 74.4 g of acrylic acid (AA), 1603.1 g of ethyl acrylate (EA), 153.9 g of methyl methacrylate (MMA), 35.4 g of diacetone acrylamide (DAAM), 543 g of deionized water, and 7.72 g of 22 %concentration sodium dodecylbenzenesulfonate in water, was gradually dispensed into the flask. From the outset of the emulsion feed, 94.1 g of an ammonium peroxodisulfate (2.0 wt % concentration) solution in water was added at a constant rate over 180 minutes to form a reaction medium; and the reaction medium was maintained from 83 °C to 85 °C during the 180 minutes. In addition, at 140 minutes from the outset of the emulsion feed, 94.4 g of a sodium carbonate (3.0% concentration) solution in water was added starting at a rate of 1.05 g per minute for 40 minutes. After 170 minutes of the feed period of the monomer emulsion had elapsed, the temperature of the reaction medium was allowed to rise from 88 °C to 90 °C and was maintained at this temperature until 200 minutes from the outset of the monomer emulsion feed. After 180 minutes of the feed period of the monomer emulsion had elapsed, the addition rate of the sodium carbonate solution was increased to a rate of 2.62 g per minute and maintained at this rate for 20 minutes. At 200 minutes from the outset of the monomer emulsion feed, the reaction medium was cooled to 75°C over 15 minutes.

[0091] When the temperature of the reaction medium was 75°C, a solution of iron (II) sulfate heptahydrate (0.01 g) in 8.2 g of water was added to the flask; and the following two mixtures were fed to the flask: the first mixture (mixl) was 30.4 g of a solution of 8.7 % concentration aqueous solution of tert-butyl hydroperoxide; and the second mixture (mix2) was 57.2 g of a 2.4 % concentration aqueous solution of sodium formaldehyde sulfoxylate. Mixl was fed to the flask over the span of 30 minutes; and mix2 was fed to the flask over the span of 30 minutes. During the addition of these two mixtures (mixl and mix2), the contents of the flask were cooled to 65 °C over the course of 30 minutes. The first polymer dispersion was obtained by the method described above.

[0092] The second polymer dispersion prepared in Aqueous Dispersion 1 was N-CAP water-borne binder which does not contain any DAAM.

[0093] The one-component waterborne acrylic adhesive of Aqueous Dispersion 1 was prepared by blending 57.5 g of the first polymer dispersion, 38.3 g of N-CAP water-borne binder, 1.0 g of Surfynol 420, 2.6 g of deionized water, 0.2 g of Foamaster MO 5090, and 0.5 g of TERGITOL™ 15- S-3 Surfactant. Aqueous Dispersion 1 was pH 6.92, Brookfield viscosity 125 mPa.s, and 41.4% solids.

[0094] Aqueous Dispersion 1 with 1.9% crosslinkable functional group: first polymer dispersion 76 wt% (crosslinkable acrylic-based polymer 85.9% EA / 8.2% MMA / 4.0% AA / 1.9% DAAM weight percent based on total weight of the crosslinkable acrylicbased polymer); and second polymer dispersion 20 wt% (N-CAP waterborne binder), weight percent based on total dry weight of the final composition;Surfynol 420 2.3 wt%, weight percent based on total dry weight of the final composition;Foamaster MO S 090 0.5 wt%, weight percent based on total dry weight of the final composition; andTERGITOL™ 15-S-3 1.2 wt%, weight percent based on total dry weight of the final composition.

[0095] C. Aqueous Dispersion 2

[0096] A first polymer dispersion with a crosslinkable acrylic-based polymer composed of 85.9% EA / 5.1% MMA / 4.0% AA / 5.0% DAAM (based on total dry weight of the crosslinkable acrylic-based polymer) was prepared by the following procedure.

[0097] Using a 5Lflask equipped with a mechanical stirrer, a charge of 546 g of deionized water was warmed to 96°C. Next, 23.8 g of 26.4 % concentration ammonium persulfate in water was poured into the flask. Subsequently, 122.8 g of a polymer seed latex with a diameter of 100 nm at 43 % concentration in water was poured into the flask. Then, 8.7 g of 3.3 % concentration ammonia in water was poured into the flask.

[0098] Over a span of 180 minutes with a constant feed rate, a monomer emulsion feed made up of 74.4 g of acrylic acid (AA), 1603.1 g of ethyl acrylate (EA), 95.6 g of methyl methacrylate (MMA), 93.7 g of diacetone acrylamide (DAAM), 543 g of deionized water, and 7.72 g of 22 % concentration sodium dodecylbenzenesulfonate in water, was gradually dispensed into the flask. From the outset of the emulsion feed, 94.1 g of an ammonium peroxodisulfate (2.0 wt % concentration) solution in water was added at a constant rate over 180 minutes to form a reaction medium; and the reaction medium was maintained from 83 °C to 85 °C during the 180 minutes. In addition, at 140 minutes from the outset of the emulsion feed, 94.4 g of a sodium carbonate (3.0% concentration) solution in water was added starting at a rate of 1.05 g perminute for 40 minutes. After 170 minutes of the feed period of the monomer emulsion has elapsed, the temperature of the reaction medium was allowed to rise from 88 °C to 90 °C and maintained at this temperature until 200 minutes from the outset of the monomer emulsion feed. After 180 minutes of the feed period of the monomer emulsion has elapsed, the addition rate of the sodium carbonate solution was increased to a rate of 2.62 g per minute and maintained at this rate for 20 minutes. At 200 minutes from the outset of the monomer emulsion feed, the reaction medium was cooled to 75°C over 15 minutes.

[0099] When the temperature of the reaction medium was 75°C, a solution of iron (II) sulfate heptahydrate (0.01 g) in 8.2 g of water was added to the flask; and the following two mixtures were fed to the flask: the first mixture (mixl) was 30.4 g of a solution of 8.7 % concentration aqueous solution of tert-butyl hydroperoxide; and the second mixture (mix2) was 57.2 g of a 2.4 % concentration aqueous solution of sodium formaldehyde sulfoxylate. Mixl was fed to the flask over the span of 30 minutes; and mix2 was fed to the flask over the span of 30 minutes. During the addition of these two mixtures (mixl and mix2), the contents of the flask were cooled to 65 °C over the course of 30 minutes.

[0100] The second polymer dispersion was N-CAP water-borne binder which does not contain any DAAM.

[0101] The one-component waterborne acrylic adhesive of composition of Aqueous Dispersion 2 was prepared by blending 57.5 g of the first polymer dispersion with 38.3 g of the second polymer dispersion (N-CAP water-borne binder), 1.0 g of Surfynol 420, 2.6 g of deionized water, 0.2 g of Foamaster MO S090, and 0.5 g of TERGITOL™ 15-S-3 Surfactant. Aqueous Dispersion 2 was pH 6.98, Brookfield viscosity 125 mPa.s, and 41.8% solids.

[0102] Aqueous Dispersion 2 with 5% crosslinkable functional group: first polymer dispersion 76 wt% (crosslinkable acrylic-based polymer 85.9% EA / 5.1% MMA / 4.0% AA / 5.0% DAAM weight percent based on total weight of the crosslinkable acrylicbased polymer), and second polymer dispersion 20 wt% N-CAP water-borne binder, weight percent based on total dry weight of the final composition;Surfynol 420 2.3 wt%, weight percent based on total dry weight of the final composition;Foamaster MO S 090 0.5 wt%, weight percent based on total dry weight of the final composition; andTERGITOL™ 15-S-3 1.2 wt%, weight percent based on total dry weight of the final composition.

[0103] Preparation of Comparative Sample CS2.

[0104] CS1 (100 parts by weight) was blended with DOW™ CR9-101 (2 parts by weight).

[0105] Preparation of Inventive Examples IE1-IE5.

[0106] A solution (ADH solution) of 10 parts by weight of adipic dihydrazide and 90 parts by weight water was prepared. IE1 was prepared by blending 3.23 parts of the ADH solution with 100 parts of Aqueous Dispersion 1. IE2 was prepared by blending 2.42 parts of the ADH solution with 100 parts ofAqueous Dispersion 1. IE3 was prepared by blending 8.06 parts of the ADH solution with 100 parts ofAqueous Dispersion 2. IE4 was prepared by blending 6.05 parts of the ADH solution with 100 parts ofAqueous Dispersion 2. IE5 was prepared by blending 4.03 parts of the ADH solution with 100 parts ofAqueous Dispersion 2.

[0107] Comparative samples (CS) and inventive examples (IE) of the present composition (waterborne adhesive composition) are provided in Table 2 below.

[0108] Table 2

[0109] D. Laminate preparation

[0110] GF-19 film (linear low density polyethylene film) was pretreated with a corona treater before lamination. GF-19 / adhesive / GF-19 laminates were prepared by a hot oil laminator at 150°F (65.6°C) nip temperature, 40 psi(0.276MPa) nip pressure, and at 27 inch / min (68.6cm / min) speed. Water-borne acrylic adhesive compositions from Table 2 were coated on a first GF-19 film with a Meyer bar to achieve a dried coat weight from 3.2 g / m2to 4.1 g / m2. Then the coated firstGF-19 film was laminated onto another (a second) GF-19 film by the hot oil laminator. The green bond strength was measured immediately after lamination. Then the laminates were cured in 50°C oven and post-lamination bond strength was evaluated at 4 days, 6 days, and 14 days as provided in Table 3 below.

[0111] Table 3. Green bond strength of the water-borne crosslinkable adhesive in LLDPE / Adhesive layer / LLDPE structure (g / 2.54cm)

[0112] E. Chemical resistance

[0113] Chemical resistance was evaluated with boil-in-bag test and 30% ethanol aqueoussolution resistant test.

[0114] Boil in bag (BIB) test of laminates: A cured laminate (22.9cmx27.9cm) was folded over to form a double layer such that the polyethylene film of one layer was in contact with the polyethylene film of the other layer. The edges were then trimmed with a paper cutter to obtain a folded piece about 12.7cmxl7.8cm. The edges were then heat sealed to form a pouch with an interior size of 10.2cmxl5.2 cm. The pouches were then filled with 100 mL of 1 / 1 / 1 sauce (blend of equal parts by weight of catsup, vinegar, and vegetable oil) through the open edge. After filling, the pouch was sealed in a manner that minimized the air entrapment inside of the pouch. The filled pouches were then carefully placed in boiling water and kept immersed in the water for 30 minutes. When completed, the extent of tunneling, delamination or leakage was compared with marked pre-existing flaws. The bags were then emptied and at least three 2.54-cm strips were cut from the pouches and T-peel bond strength was measured as soon as possible.

[0115] Table 4. Chemical resistance by Boil-in-bag test with 1 / 1 / 1 sauce (adhesion bond strength)

[0116] F. Alcohol resistance

[0117] 30% ethanol aqueous solution resistance to test the chemical resistance by immersing the lin (2.54cm) laminate strips in the ethanol solution in a 50ml glass jar and aging in 50°C for lOOhrs. The strips were then observed and evaluated for any delamination. If no delamination, bond strength was tested.

[0118] Alcohol aging was conducted by immersing the 1 inch (2.54cm) laminate strips into30% Ethanol aqueous solution and aged at 50°C for lOOhrs. The T-bond strength was measured, and the appearance was observed.

[0119] Table 5. 30% ethanol aging for lOOhrs

[0120] When compared to CS1, the inventive examples IE1 to IE5 have significantly improved adhesion bond strength and chemical resistance (both boil-in-bag and alcohol resistance). When compared to CS2 which uses a conventional isocyanate crosslinker, the inventive examples IE1 to IE5 have improved adhesion strength. The inventive examples IE1 to IE5 also have acceptable chemical resistance although the chemical resistance is lower than that of CS2. Increased oven drying time before lamination does not lead to further performance improvement indicating the standing drying process (2min at the lamination condition) is suitable for the inventive waterborne adhesive application.

[0121] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.

Claims

CLAIMS1. A composition comprising:(A) a first polymer dispersion comprising a crosslinkable acrylic-based polymer comprising a. at least two C1-C20 alkyl (meth)acrylate monomers, b. a monomer having an acid group, c. an ethylenically unsaturated compound having at least one keto group or at least one aldehyde group, and(B) a second polymer dispersion comprising a non-crosslinkable acrylic polymer comprising a C1-C20 alkyl (meth)acrylate monomer; and(C) a crosslinking agent.

2. The composition of claim 1 wherein the crosslinkable acrylic-based polymer comprises ethyl acrylate, methyl methacrylate, acrylic acid, and diacetone acrylamide (DAAM).

3. The composition of any of claims 1-2 wherein the non-crosslinkable acrylic polymer comprises a C1-C20 alkyl (meth)acrylate monomer and greater than 5 wt% of a meth(acrylic) acid monomer.

4. The composition of any of claims 1-3 wherein the crosslinking agent is adipic acid dihydrazide (ADH).

5. The composition of any of claims 1-4 wherein the composition comprises from 59.9 wt% to 84.9 wt% of the crosslinkable acrylic-based polymer; from 15 wt% to 35 wt% of the non-crosslinkable acrylic polymer; and from 0.1 wt% to 5 wt% of the crosslinking agent, wherein weight percent is based on total dry weight of the composition.

6. The composition of any of claims 1-5 wherein the composition comprises from 59.9 wt% to 84.9 wt% of the crosslinkable acrylic-based polymer comprising monomers of ethyl acrylate, methyl methacrylate, acrylic acid, and diacetone acrylamide (DAAM); from 15 wt% to 35 wt% of the non-crosslinkable acrylic polymer; and from 0.1 wt% to 5 wt% of the crosslinking agent comprising ADH, wherein weight percent is based on total dry weight of the composition.

7. The composition of any of claims 1-6 wherein the composition is void of styrene.

8. A laminate comprising: a first substrate; a second substrate; and an adhesive layer disposed between the first substrate and the second substrate, the adhesive layer comprising an adhesive composition comprising(A) a crosslinked acrylic-based polymer comprising(i) at least two C1-C20 alkyl (meth)acrylate monomers,(ii) a monomer having an acid group,(iii) an ethylenically unsaturated compound having at least one keto group or at least one aldehyde group, and(B) a non-crosslinkable acrylic polymer comprising a C1-C20 alkyl (meth)acrylate monomer; and(C) a crosslinking agent.

9. The laminate of claim 8 wherein the adhesive composition comprises from 60 wt% to 80 wt% of the crosslinked acrylic-based polymer; from 15 wt% to 25 wt% of the non-crosslinkable acrylic polymer; and from 2 wt% to 10 wt% of the crosslinking agent, wherein weight percent is based on total weight of the adhesive layer.

10. The laminate of any of claims 8-9 wherein the adhesive composition comprises from 60 wt% to 80 wt% of the crosslinked acrylic-based polymer comprising monomers of ethyl acrylate, methyl methacrylate, acrylic acid, and diacetone acrylamide (DAAM); from 15 wt% to 25 wt% of the non-crosslinkable acrylic polymer; and from 2 wt% to 10 wt% of the crosslinking agent comprising ADH, wherein weight percent is based on total weight of the adhesive layer.

11. An article comprising a laminate from any of claims 8-10.

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