Acrylic-Based Adhesive Composition with Ethylene/Ester Copolymer

Abstract

The present disclosure is directed to a water-based pressure-sensitive adhesive composition. In an embodiment, the water-based pressure-sensitive adhesive composition includes (A) an acrylic dispersion composed of particles of (i) an acrylic-based polymer with a glass transition temperature (Tg) less than -20° C., and (ii) a surfactant. The water-based pressure-sensitive adhesive composition also includes (B) an ethylene ester dispersion composed of (i) particles of an ethylene ester copolymer having from 1 wt % to less than 50 wt% acrylate comonomer, and (ii) a dispersant. Further disclosed are articles with the water-based pressure-sensitive adhesive composition.

Claims

1. A water-based pressure-sensitive adhesive composition comprising: (A) an acrylic dispersion comprising particles of (i) an acrylic-based polymer with a glass transition temperature (Tg) less than -20° C.; and (ii) a surfactant; and (B) an ethylene ester dispersion comprising (i) particles of an ethylene ester polymer having from 1 wt% to less than 50 wt% of an acrylate comonomer; and (ii) a dispersant.

2. The water-based pressure-sensitive adhesive composition of claim 1 wherein the acrylic-based polymer includes one or more acrylic-based monomers selected from the group consisting of acrylic acid (AA), butyl acrylate (BA), ethylhexyl acrylate (2-EHA), ethyl acrylate (EA), methyl acrylate (MA), butyl methacrylate (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, C.sub.12 to C.sub.18 alkyl methacrylates, cyclohexyl methacrylate, methacrylic acid, and combinations thereof.

3. The water-based pressure-sensitive adhesive of claim 1 wherein the acrylic-based polymer includes a monomer selected from the group consisting of styrene, vinyl ester, and combinations thereof.

4. The water-based pressure-sensitive adhesive composition of claim 1 wherein the acrylic-based polymer has a Tg from -80° C. to -20° C.

5. The water-based pressure-sensitive adhesive composition of claim 1 wherein the particles of the ethylene ester polymer have a volume average particle size from 0.1 micron to 2.0 microns.

6. The water-based pressure-sensitive adhesive composition of claim 1 wherein the ethylene ester polymer comprises units of ethylene and a comonomer selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl methacrylate, and combinations thereof.

7. The water-based pressure-sensitive adhesive composition of claim 1 wherein the ethylene ester polymer has a melt index from 1 g/10 min to 60 g/10 min.

8. The water-based pressure-sensitive adhesive composition of claim 1 wherein the ethylene ester polymer has a density from 0.920 g/cc to 0.960 g/cc, a melting point, Tm, from 70° C. to 110° C., and a Vicat softening point from 40° C. to 80° C.

9. The water-based pressure-sensitive adhesive composition of wherein the dispersant is selected from the group consisting of a long chain fatty acid having from 14 to 40 carbon atoms, an anionic surfactant, a cationic surfactant, a nonionic surfactant, a polyethylene with acid functionality, a polypropylene with acid functionality, and combinations thereof.

10. The water-based pressure-sensitive adhesive composition of claim 1 wherein the ethylene ester dispersion comprises a neutralizing agent.

11. The water-based pressure-sensitive adhesive composition of claim 1 comprising (A) from 40 wt% to 99.8 wt% of the acrylic dispersion; (B) from 10 wt % to 0.2 wt% of the ethylene-based polymer dispersion; (C) from 0 wt% to 50 wt% tackifier; wherein weight percent is based on the total dry weight of the water-based pressure-sensitive adhesive composition.

12. An article comprising: a first substrate; and a layer of a water-based pressure-sensitive adhesive composition on the first substrate, the water-based pressure-sensitive adhesive composition comprising (A) an acrylic dispersion comprising particles of (i) an acrylic-based polymer with a glass transition temperature (Tg) less than -20° C.; and (ii) a surfactant; and (B) an ethylene ester dispersion comprising: (i) particles of an ethylene ester polymer having from 1 wt% to less than 50 wt% of an acrylate comonomer; and (ii) a dispersant.

Description

DETAILED DESCRIPTION

[0041] The present disclosure relates to a water-based pressure-sensitive adhesive composition. In an embodiment, the water-based pressure-sensitive adhesive composition includes (A) an acrylic dispersion composed of particles of (i) an acrylic-based polymer with a glass transition temperature (Tg) less than -20° C., and (ii) a surfactant. The water-based pressure-sensitive adhesive composition also includes (B) an ethylene ester dispersion. The ethylene ester dispersion is composed of (i) an ethylene/ester polymer (EEP) and (ii) a dispersant. The EEP contains from 1 wt% to less than 50 wt% acrylate-based comonomer and is in the form of particles.

A. Acrylic Dispersion

[0042] The water-based PSA composition includes an acrylic dispersion. The term “water-based PSA composition” is a pressure sensitive adhesive composition wherein water is the continuous phase, i.e., a composition having an aqueous medium. The acrylic 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 reacts with the 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 an acrylic dispersion 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.

[0043] The acrylic-based polymer has a Tg less than -20° C., or from -80° C. to -20° C., or from -70° C. to -30° C., or from -60° C. to -40° C. and a Mw from greater than 100,000 daltons to 10,000,000 daltons. Nonlimiting examples of suitable acrylic-based monomers include acrylic acid (AA), butyl acrylate (BA), ethylhexyl acrylate (2-EHA), ethyl acrylate (EA), methyl acrylate (MA), butyl methacrylate (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, C.sub.12 to C.sub.18 alkyl methacrylates, cyclohexyl methacrylate, methacrylic acid, and combinations thereof. In addition to acrylic-based monomer, the acrylic-based polymer may also include monomer such as 2-hydroxyethyl acrylate (2-HEA), styrene (STY), vinyl ester, vinyl acetate, and combinations thereof.

[0044] The acrylic-based dispersion includes a surfactant. Nonlimiting examples of suitable surfactant 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.

[0045] 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.

[0046] In an embodiment, the acrylic dispersion includes particles of an acrylic-based polymer having the following properties: [0047] (i) two or more monomer subunits selected from any combination of 2-EHA, MA, MMA, STY, 2-HEA, AA, BA, EA, VA, and BMA; and [0048] (ii) a Tg from -60° C. to -30° C.

[0049] In an embodiment, the acrylic dispersion includes particles of an acrylic-based polymer having the following properties: [0050] (i) monomer subunits of 2-EHA, EA, MMA, and AA; and [0051] (ii) a Tg from -60° C. to -30° C.

[0052] In an embodiment, the acrylic dispersion includes particles of an acrylic-based polymer having the following properties: [0053] (i) monomer subunits of 2-EHA, MMA, STY, 2-HEA, AA, and BA; and [0054] (ii) a Tg from -60° C. to -30° C.

B. Ethylene Ester Dispersion

[0055] The water-based PSA composition includes an ethylene ester dispersion. The ethylene ester dispersion includes particles of an ethylene/ester polymer (EEP), a dispersant, and water. The ethylene/ester polymer consists of (i) ethylene, (ii) an acrylate comonomer, and (iii) optionally one or more termonomers. The EEP contains greater than 50 wt% ethylene monomer and from 1 wt% to less than 50 wt% acrylate comonomer. Weight percent is based on the total weight of the EEP.

[0056] An “ethylene/ester polymer,” (interchangeably referred to as “EEP”) as used herein, is an ethylene-based polymer composed of (i) ethylene and (ii) an acrylate-based comonomer, and (iii) optionally one or more termonomers. The acrylate-based comonomer is an acrylic-based monomer, having Structure (1) below:

##STR00002##

[0057] wherein R.sub.1 is a C.sub.1-C.sub.18 alkoxy group and R.sub.2 is hydrogen or a methyl group. The R.sub.1 group may be functionalized with one to three, moieties such as hydroxy, alkoxy, and oxirane, for example. The acrylate comonomer includes acrylates and methacrylates.

[0058] The ethylene/ester polymer is an ethylene-based polymer (containing greater than 50 wt% of units derived from ethylene) and is therefore distinct compared to the acrylic-based polymer in the acrylic dispersion. The ethylene/ester polymer is an ethylene-based polymer (containing greater than 50 wt% of units derived from ethylene) and is present to the exclusion of ethylene/ester copolymer prepared by emulsion polymerization in water.

[0059] In an embodiment, the ethylene ester dispersion includes particles of an EEP consisting of (i) ethylene, (ii) from 10 wt% to less than 50 wt% of an acrylate comonomer, and (iii) optionally one or more termonomers. It is understood that the particles of the EEP are distinct from the particles of the acrylic-based polymer present in the acrylic dispersion Nonlimiting examples of suitable termonomers include C.sub.3-C.sub.12 a-olefins, acrylate/methacrylate (that is different than the acrylate-based comonomer), glycidyl methacrylate, vinyl acetate, acrylic acid, and methacrylic acid. When present, the amount of termonomer in the EEP is from greater than 0 wt% to less than 30%, or from 1 wt% to 10 wt%, or from 3 wt% to 8 wt%, with weight percent based on the total weight of the EEP. When the termonomer is present, it is understood the total weight percent of (i) units derived from ethylene, (ii) units derived from acrylate-based comonomer, and (iii) units derived from the termonomer amount to 100 wt% of the EEP.

[0060] The EEP has a melt index (MI) from 1.0 g/10 min to 600 g/10 min, or from 1.0 g/10 min to 125 g/10 min, or from 5.0 g/10 min to 60 g/10 min, or from 6.0 g/10 min to 50 g/10 min.

[0061] The EEP has a density from 0.90 g/cc to 0.980 g/cc, or from 0.920 g/cc to 0.950 g/cc, or from 0.924 g/cc to 0.950 g/cc.

[0062] The EEP has a melting point, Tm, from 70° C. to 110° C., or from 80° C. to 105° C., or from 82° C. to 101° C.

[0063] The EEP has a Vicat softening point from 40° C. to 80° C., or from 45° C. to 75° C., or from 49° C. to 70° C.

[0064] The EEP is in the form of particles, the particles having a volume average particle size from 0.1 micron to 4.0 microns, or from 0.3 microns to 1.9 microns, or from 0.4 microns to 1.8 microns.

[0065] In an embodiment, the EEP is an ethylene-based copolymer consisting of (i) ethylene and (ii) acrylate comonomer. The EEP contains from 1 wt% to less than 50 wt%, or from 5 wt% to 40 wt%, or from 9 wt% to 35 wt% of acrylate comonomer. Weight percent is based on the total weight of the EEP.

[0066] In an embodiment, the ethylene ester dispersion includes particles of EEP consisting of

[0067] (i) ethylene and (ii) an acrylate with a C.sub.1-C.sub.8 alkoxy group, or C.sub.1-C.sub.4 alkoxy group, and having one, some, or all of the following properties: [0068] (i) an acrylate comonomer content from 5 to 40 wt%, or from 9 to 35 wt%; and/or [0069] (ii) a volume average particle size from 0.1 to 2.0 microns, or from 0.3 to 1.9 microns; and/or [0070] (iii) a melt index (MI) from 1.0 to 125 g/10 min, or from 6.0 to 50 g/10 min; and/or [0071] (iv) a density from 0.920 to 0.960 g/cc, or from 0.924 to 0.944 g/cc; and/or [0072] (v) a melting point, Tm, from 70° C. to 110° C., or from 88° C. to 101° C.; and/or [0073] (vi) a Vicat softening point from 40° C. to 80° C., or from 49° C. to 70° C.

[0074] In an embodiment, the ethylene ester dispersion includes particles of EEP consisting of

[0075] (i) ethylene, (ii) an acrylate comonomer, and (iii) an acrylate-based termonomer (that is different than the acrylate based comonomer) or vinyl acetate, and having one, some, or all of the following properties: [0076] (i) an acrylate comonomer content from 1 wt% to 20 wt%, or from 4 wt% to 10 wt%; and/or [0077] (ii) an acrylate termonomer content from 5 wt% to 40 wt%, or from 15 wt% to 30 wt%; and/or [0078] (ii) a volume average particle size from 0.1 to 2.0 microns, or from 0.3 to 1.9 microns; and/or [0079] (iii) a melt index (MI) from 1.0 to 20 g/10 min, or from 5.0 to 10 g/10 min; and/or [0080] (iv) a density from 0.90 to 0.980 g/cc, or from 0.3 to 0.96 g/cc; and/or [0081] (v) a melting point, Tm, from 70° C. to 90° C., or from 80° C. to 85° C.

[0082] Commercially available examples of suitable ethylene ester polymers include, but are not limited to, ELVALOY™ AC 15024S, ELVALOY™ AC 34035, ELVALOY™ AC 1609, ELVALOY™ AC 1820, ELVALOY™ AC 3717, ELVALOY™ AC 3427, and AMPLIFY™ EA 103, available from Dow Inc.

[0083] The ethylene ester dispersion includes a dispersant. The dispersant provides colloidal stability for the EEP while in the ethylene ester dispersion. The dispersant is selected from a long chain fatty acid having from 14 to 40 carbon atoms, an anionic surfactant, a cationic surfactant, a nonionic surfactant, a polyethylene with acid functionality, a polypropylene with acid functionality, a polyethylene/polypropylene block copolymer, and combinations thereof. In an embodiment, the dispersant is a long chain fatty acid having from 14 to 40 carbon atoms, or from 16 to 36 carbon atoms, or from 18 to 24 carbon atoms. The dispersant may optionally be neutralized with a base such as, potassium hydroxide, sodium hydroxide, and/or dimethylethanolamine. Nonlimiting examples of long chain fatty acids suitable for the dispersant include lauric acid (C.sub.12), palmitic acid (C.sub.16), oleic acid (C.sub.18) stearic acid (C.sub.18), arachidic acid (C.sub.20), euricic acid (C.sub.22), behenic acid (C.sub.22), and combinations thereof.

[0084] In an embodiment, the dispersant is an anionic surfactant. Nonlimiting examples of anionic surfactants suitable for the dispersant include sodium lauryl ether sulfonate, sodium dodecylbenzene sulfonate, sodium C.sub.14-C.sub.16 alpha olefin sulfonate, and DOWFAX™ 2A1 available from Dow Inc.

[0085] In an embodiment, the dispersant is a cationic surfactant. Nonlimiting examples of cationic surfactants suitable for the dispersant include stearamidopropyl dimethylamine.

[0086] In an embodiment, the dispersant is a nonionic surfactant. Nonlimiting examples of nonionic surfactants suitable for the dispersant include poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) and poly(ethylene glycol) (PEG-PPG-PEG) alkyl ethers.

[0087] In an embodiment, the dispersant is polyethylene or polypropylene with acid functionality. Nonlimiting examples of polyethylene or polypropylene with acid functionality include ethylene copolymers with acrylic acid, methacrylic acid, maleic acid, or maleic anhydride.

[0088] In an embodiment, the dispersant is an ethylene acid copolymer. An “ethylene acid copolymer,” (interchangeably referred to as “EAC”) as used herein, includes copolymerized comonomers of (a) ethylene; (b) from 3 wt % to less than 50 wt % of at least one C.sub.3 to C.sub.8 α,β ethylenically unsaturated carboxylic acid; and, optionally, (c) from 10 wt % to 30 wt % of at least one C.sub.3 to C.sub.8 α,β ethylenically unsaturated carboxylic acid ester, based on the total weight of monomers present in the ethylene acid copolymer.

[0089] The α,β-ethylenically unsaturated C.sub.3 to C.sub.8 carboxylic acid, component (b) includes, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid (trans-butenoic acid), isocrotonic acid (cis- butenoic acid), vinylacetic acid, (E)-4-methoxy-4-oxo-but-2-enoic acid, (Z)-4-ethoxy-4- oxo-but-2-enoic acid, vinyllactic acid, maleic acid, 2-methylmaleic acid or aconitic acid; or mixtures thereof. In an embodiment, the C.sub.3 to C.sub.8 α,β ethylenically unsaturated carboxylic acid is acrylic acid, methacrylic acid, or a combination of acrylic acid and methacrylic acid.

[0090] The ethylene acid copolymer may optionally include C.sub.3 to C.sub.8 α,β ethylenically unsaturated carboxylic acid ester, component (c). When the C.sub.3 to C.sub.8 α,β ethylenically unsaturated carboxylic acid ester component (c) is present, component (c) may include monoesters or, in some examples, diesters of α,β- unsaturated dicarboxylic acids with primary, secondary and/or tertiary saturated monohydric alcohols having from 1 carbon atom to 20 carbon atoms. The acid esters may be, for example, methyl, ethyl, propyl, butyl or the 2-ethylhexyl esters of acrylic acid, of methacrylic acid and/or itaconic acid, or the corresponding monoesters or diesters of maleic acid, fumaric acid or citraconic acid.

[0091] In an embodiment, the ethylene acid dispersion includes the neutralizing agent. A “neutralizing agent,” as used herein, is a base which reacts with the acid functionality in the EAC in an acid-base reaction to form a salt. When present, the neutralizing agent is used to control pH and provide stability to the formulated pressure sensitive adhesive composition. The neutralizing agent is present in an amount from greater than 0 wt% to 2 wt%, or from 0.1 wt% to 1.5 wt% based on total dry weight of the water based pressure-sensitive adhesive composition.

[0092] In an embodiment, neutralization of the EAC, is from 25% to 200% on a molar basis; or from 50% to 150% percent on a molar basis, or from 50% to 120% on a molar basis; or or from 50% to 110% percent on a molar basis. Nonlimiting examples of suitable neutralizing agents include hydroxides, carbonates, hydrogen carbonates, amines, and combinations thereof.

[0093] Nonlimiting examples of suitable hydroxides include ammonium hydroxide, potassium hydroxide, lithium hydroxide, and sodium hydroxide.

[0094] Nonlimiting examples of suitable carbonates include sodium carbonate, sodium bicarbonate, potassium carbonate, and calcium carbonate.

[0095] Nonlimiting examples of suitable amines include aqueous ammonia, monoethanolamine, diethanolamine, triethanolamine, ammonia, monomethylamine, dimethylamine, trimethylamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, diisopropanolamine, N,N-dimethylethanolamine, mono-n-propylamine, dimethyl-n propylamine, N-methanol amine, N-aminoethylethanolamine, N-methyldiethanolamine, monoisopropanolamine, N,N-dimethyl propanolamine, 2-amino-2-methyl-1-propanol, tris(hydroxymethyl)-aminomethane, N,N,N′N′-tetrakis(2-hydroxylpropyl)ethylenediamine, 1,2-diaminopropane, 2-amino-2-hydroxymethyl-1,3-propanediol, N,N′-ethylenebis[bis(2-hydroxypropyl)amine]toluene-p-sulphonate, or cyclic amines such as morpholine, piperazine, piperidine, and combinations thereof.

[0096] In an embodiment, the water-based pressure-sensitive adhesive composition includes from 0.1 to 25 wt%, or from 0.1 to 10 wt%, or from 0.2 to 6 wt%, or from 0.3 to 4 wt% of the ethylene ester dispersion, based on the total weight of the water-based pressure-sensitive adhesive composition.

[0097] In an embodiment, the water-based pressure-sensitive adhesive composition includes from 0.1 to 25 wt%, or from 0.1 to 10 wt%, or from 0.2 to 6 wt%, or from 0.3 to 4 wt% of the EEP, based on the total dry weight of the adhesive composition.

C. Tackifier

[0098] In an embodiment, the water-based pressure sensitive adhesive composition includes a tackifier. Suitable tackifiers include, but are not limited to, rosin resins including rosin acid and/or rosin ester obtained by esterifying rosin acid with alcohols or an epoxy compound and/or its mixture, non-hydrogenated aliphatic C.sub.5 resins, hydrogenated aliphatic C.sub.5 resins, aromatic modified C.sub.5 resins, terpene resins, hydrogenated C.sub.9 resins, (meth)acrylic resins, and combinations thereof. (Meth)acrylic resins suitable as tackifiers are described in references US 4,912,169, US 2002/055587, and US 9,605,188. The water-based pressure-sensitive adhesive composition contains from greater than 0 wt% to 50 wt%, or from 5 wt% to 40 wt%, or from 7 wt% to 30 wt%, or from 8% to 15 wt% of the tackifier based on total dry weight of the water-based pressure sensitive adhesive composition.

D. Additives

[0099] The water-based pressure sensitive adhesive composition may further 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, plasticizer, adhesion promoter, and combinations thereof.

[0100] In an embodiment, the water-based pressure sensitive adhesive composition includes from greater than 0 wt% to 5 wt% thickener, based on the total dry weight of the water-based pressure sensitive adhesive composition. Suitable thickeners include, but are not limited to, ACRYSOL™, UCAR™ and CELLOSIZE™ which are commercially available from The Dow Chemical Company, Midland, Michigan.

E. PSA Composition

[0101] The water-based PSA composition contains [0102] (A) from 40 wt% to 99.9 wt%, or from 93 wt% to 99.8 wt%, or from 95 wt% to 99.7 wt% of the acrylic-based dispersion; [0103] (B) from 10 wt% to 0.1 wt%, or from 7 wt% to 0.2 wt%, or from 5 wt% to 0.3 wt% of the ethylene-based polymer dispersion; and [0104] (C) 0 wt%, or from greater than 0 wt% to 50 wt%, or from 5 wt% to 40 wt%, or from 7 wt% to 30 wt%, or from 8% to 15 wt% tackifier, wherein weight percent is based on the total dry weight of the water-based pressure-sensitive adhesive composition. It is understood that the aggregate dry weight of components (A), (B), and (C) amount to 100 dry wt%.

F. Article

[0105] The present disclosure provides an article. The article includes a first substrate and a layer of a water-based PSA composition on the first substrate (hereafter PSA layer). The water-based PSA composition is any water-based PSA composition as previously disclosed herein and includes: the acrylic dispersion (A) composed of (i) the acrylic-based polymer with a glass transition temperature (Tg) less than -20° C., and (ii) the surfactant; the ethylene ester dispersion (B) composed of (i) particles of an ethylene/ester polymer (EEP) and (ii) a dispersant; and (C) optional tackifier. The ethylene/ester polymer contains from 1 wt% to less than 50 wt% acrylate comonomer.

[0106] In an embodiment, the article is a pressure sensitive adhesive article. A “pressure sensitive adhesive article,” as used herein, is an article in which a pressure sensitive adhesive (PSA) is adhered to a first substrate, the PSA having an “available surface,” the available surface being an exposed surface, available to make contact with a second substrate. The “available surface” is composed of any water-based PSA composition as previously disclosed herein. The available surface of the PSA may or may not be in contact with a release material. A “release material,” as used herein, is a material that forms a weak bond with the PSA, such that the PSA may be readily removed by hand to expose the available surface.

[0107] The article includes a first substrate. The first substrate is a film, a cellulose-based material, a fabric, a tape, or a release liner, and combinations thereof.

[0108] In an embodiment, the first substrate is a film. Nonlimiting examples of films suitable for the first substrate include plastic films (unstretched film, or uniaxially stretched film, or biaxially stretched film) such as propylene-based polymer film, ethylene-based polymer film, ethylene/propylene copolymer films, polyester films, poly(vinyl chloride) films, metallized films, foam substrates such as polyurethane foams, and polyethylene foams; and metal foils such as aluminum foils or copper foils.

[0109] In an embodiment, the first substrate is a cellulose-based material. Nonlimiting examples of cellulose-based material suitable for the substrate include paper such as craft paper, crepe paper and Japanese paper, labels, and cardboard.

[0110] In an embodiment, the first substrate is a fabric. Nonlimiting examples of fabric suitable for the substrate included cotton fabrics, staple-fiber fabrics, nonwoven fabrics such as polyester nonwoven fabrics, vinyl on nonwoven fabrics, and combinations thereof.

[0111] In an embodiment, the first substrate is a release liner. Nonlimiting examples of suitable materials for the release liner include fluorocarbon polymers (e.g., polytetrafluoroethylene, polychlorotrifluoro-ethylene, polyvinyl fluoride, polyvinylidene fluoride, a tetrafluoroetylene-hexafluoropropylene copolymer, a chlorofluoroethylene-vinylidene fluoride copolymer, etc.), siliconized paper or film, and non-polar polymers (e.g., olefin-based resins such as ethylene-based polymers and propylene-based polymers.

[0112] In an embodiment, the thickness of the first substrate (film, cellulose-based material, fabric, tape, or release liner) is from 10 microns to 10000 microns, or from 10 microns to 1000 microns, or from 20 microns to 500 microns, or from 50 microns to 100 microns, or from 100 microns to 200 microns, or from 200 microns to 500 microns.

[0113] The PSA layer is formed by applying, on one, or both, first substrate surface(s), the water-based PSA composition, followed by drying or curing. The water-based PSA composition can be any water-based PSA composition as previously disclosed herein. For the application of the PSA composition a coater, e.g., a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, curtain coater, slot die coater, comma coater, knife coater or the like, can be employed. In an embodiment, the surface(s) of the substrate to which the pressure-sensitive adhesive layer is applied is/are subjected to a surface treatment. Nonlimiting examples of suitable surface treatments include a primer coating, and a corona discharge treatment prior to application of the PSA layer onto the substrate surface(s).

[0114] In an embodiment, the thickness of the PSA layer on the substrate surface is from 1 micron to 500 microns, or from 10 microns to 110 microns, or from 30 microns to 90 microns, or from 1 micron to 10 microns, or from 10 microns to 50 microns.

[0115] In an embodiment, the article is a multi-layer PSA article. A “multi-layer PSA article,” as used herein, includes a substrate and two or more PSA layers such that a first PSA layer is in contact with the substrate and a second PSA layer is in contact with the first PSA layer. The multi-layer PSA article may include additional PSA layers wherein each additional PSA layer is in contact with a preceding PSA layer, the PSA layers arranged in a stacked manner. For example, the multi-layer PSA article can include a third PSA layer, the third PSA layer in contact with, and stacked upon, the second PSA layer. The multi-layer PSA article can include a fourth PSA layer, the fourth PSA layer in contact with, and stacked upon, the third PSA layer. The multi-layer PSA article can include a fifth PSA layer, the fifth PSA layer in contact with, and stacked upon, the fourth PSA layer. At least one of the PSA layers of the multi-layer PSA article is composed of any water-based PSA composition as previously disclosed herein.

[0116] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.

EXAMPLES

[0117] Materials used in the examples are provided in Table 1A and 1B below.

TABLE-US-00001 Materials used in the comparative samples (CS) and inventive examples (IE) Material/Description Properties Source TERGITOL™ 15-S-9 Nonionic surfactant The Dow Chemical Company AEROSOL OT-75 Anionic surfactant Cytec Solvay Group DISPONIL FES 77 Anionic surfactant BASF SE SURFYNOL 440 Nonionic dynamic wetting agent Evonik ACRYSOL™ RM-2020 Rheology modifier/thickener Dow Inc. Sodium carbonate, ammonium persfulate, tert-butyl hydroperoxide, sodium formaldehyde bisulfite, n-dodecyl mercaptan Various chemicals Sinoreagent Company 2-ethylhexyl acrylate (“2-EHA”), ethyl acrylate (“EA”), methyl methacrylate (“MMA”), acrylic acid (“AA”), butyl acrylate (“BA”) Acrylic dispersion monomers The Dow Chemical Company Oleic acid C.sub.18H.sub.34O.sub.2, 282.5 g/mol d= 0.89 g/cc 90% purity reagent grade Sigma-Aldrich Licocene 4351 Grafted maleic anhydride polyethylene wax Clariant Dimethylethanolamine Neutralizing agent Sigma-Aldrich 30% potassium hydroxide Neutralizing agent Sigma-Aldrich PRIMACOR™ 5980i Dispersant Ethylene acrylic acid copolymer (20 wt% acrylic acid) The Dow Chemical Company Pluronic F-108 Dispersant Poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEG-PPG-PEG) BASF SE NUCREL™ 960 Dispersant Ethylene methacrylic acid copolymer (15 wt% methacrylic acid) The Dow Chemical Company

TABLE-US-00002 Ethylene ester resins (EER) Density (g/cc) DSC Melt Point, (Tm) (°C) Vicat Softening Point (°C) MI % MA %EA %BA %2-EHA %GMA %VA %AA ELVALOY™ AC 15024S 0.944 88 --- 50 24 --- --- --- --- --- --- ELVALOY™ AC 34035 0.93 90 --- 40 --- --- 35 --- --- --- --- ELVALOY™ AC 1609 0.93 101 70 6 9 --- --- --- --- --- --- ELVALOY™ AC 3717 0.924 96 55 7 --- --- 17 --- --- --- --- AMPLIFY™ EA 103 0.93 95 49 21 --- 19.5 --- --- --- --- --- ELVALOY™ AC 1820 0.942 92 54 8 20 --- --- --- --- --- --- ELVALOY™ AC 3427 0.926 94 45 4 --- --- 27 --- --- --- --- EER1 0.95 82 52.5 8 --- --- --- --- 9 15 --- EER2 --- --- --- 125 --- --- --- 20 --- --- 2 EER3 --- --- --- 25 --- --- --- 20 --- --- 2

[0118] EER1, EER2, and EER3

[0119] Experimental copolymers EER1, EER2, and EER3 may be prepared by standard free-radical copolymerization methods, using high pressure, operating in a continuous manner. Monomers are fed into the reaction mixture in a proportion which relates to the monomer’s reactivity, and the amount desired to be incorporated. In this way, uniform, near-random distribution of monomer units along the chain is achieved. Polymerization in this manner is well known and is described for example, in U.S. Pat. number 4,351,931.

A. Melt Index (MI)-Melt Viscosity (Mv) Relationship

[0120] Melt Index at 190° C. may be estimated from Melt Viscosity at 140° C. according to the following calculation taken from Shenoy, A.V.; Saini, D.R.; Nadkarni, V.M. Polymer 1983, 24, 722-728. MI at a given temperature, e.g., 140° C., may be estimated from Melt Viscosity at the same temperature as follows:

[00003]$MI=\frac{49,800\times \rho \times L}{MeltViscosity}$

[0121] where MI is given in g/10 min, ρ is the polymer density in g/cm.sup.3, L is the weight used in the MI measurement in kg (typically 2.16 kg), and the melt viscosity is given in poise. Next, a rearrangement of the form of the Williams-Landel-Ferry equation provided by Shenoy et al. in the above reference may be used to estimate the MI at one temperature, MI(T.sub.2) e.g., 190° C., from the MI at another temperature, MI(T.sub.1) e.g. 140° C.:

[00004]$MI\left(T_2\right)=MI\left(T_1\right)\times {10}^{\left(\frac{8.86\left(T_2-T_S\right)}{101.6+\left(T_2-T_S\right)}-\frac{8.86\left(T_1-T_S\right)}{101.6+\left(T_1-T_S\right)}\right)}$

[0122] where T.sub.s is the standard reference temperature which is the polymer glass transition temperature plus 50 K, T.sub.2 is the temperature in K at which MI is to be calculated, and T.sub.1 is the temperature in K at which the MI is known. If the polymer glass transition temperature is not known, it may be estimated using the Fox equation from the glass transition temperature of the homopolymers of the component monomers:

[00005]$\frac{1}{T_g}={\displaystyle .Math.\frac{w_i}{T_{g.i}}}$

where T.sub.g is the estimated T.sub.g of the desired copolymer, w.sub.l is the weight fraction of the i-th component monomer in the desired copolymer, and T.sub.g,l is the glass transition temperature of the homopolymer of the i-th component monomer.

[0123] As an example, the MI at 190° C. for the EAA Honeywell A-C 5120 polymer may be estimated from its melt viscosity at 140° C. (6 poise), density (0.93 g/cm.sup.3), and glass transition temperature calculated for a copolymer of 85% ethylene and 15% acrylic acid.

TABLE-US-00003 MI- Mv relationship for various dispersion components Type Name E VA AA Melt Viscosity 140° C. MI 140° C. p T.sub.g (K, calculated) MI 190° C. (calculated) EAA Honeywell A-C 5120 85% 15% 6 16673 0.93 208 62309 Oxidized EVA Honeywell A-C 645P* 94% 6% 3.75 26964 0.94 201 92657 Oxidized PE Honeywell A-C 655 100% 2.1 47637 0.93 193 156040 Oxidized PE Honeywell A-C 656 100% 1.85 53493 0.92 193 175222 EVA Honeywell A-C 405 91.5% 8.5% 6 16494 0.92 211 63329 EAA Honeywell A-C 540 95% 5% 5.75 17398 0.93 198 59286 EAA Honeywell A-C 580 90% 10% 6.5 15473 0.935 203 55084 EAA Honeywell A-C 5180 80% 20% 6.25 16092 0.935 214 63491 *Monomer composition estimated, wt% based on total weight of material E-ethylene, VA-vinyl acetate, AA-acrylic acid

1. Preparation of Acrylic Dispersion

A. Acrylic Dispersion 1

[0124] Acrylic dispersion 1 is prepared according to the following procedure. A four liter, five-neck reactor equipped with a condenser, a mechanical stirrer, a temperature-controlled thermocouple and inlets for initiators and monomers, is fed with 540 g of deionized (“DI”) water and heated to 87° C. under a gentle nitrogen flow. In a separate container, a monomer emulsion is prepared by mixing 400 g of DI water, 11.9 g of DISPONIL FES 77, 5 g of TERGITOL™ 15-S-9, 4 g of sodium carbonate, and 2,024 g of a monomer mixture composed of 71.5 wt% of 2-ethylhexyl acrylate (“2-EHA”), 18.5 wt% of ethyl acrylate (“EA”), 9 wt% of methyl methacrylate (“MMA”), and 1 wt% of acrylic acid (“AA”). Next, a solution of a mixture of 1.3 g of sodium carbonate and 8.3 g of ammonium persulfate (“APS” as initiator) in 32 g DI water is added into the reactor. Immediately after addition of the solution of sodium carbonate and APS, the monomer emulsion is fed into the reactor. The feeding proceeds for 80 minutes. Upon completion of the monomer emulsion addition, the reaction mixture is cooled to 60° C. before gradual addition of a solution of tert-butyl hydroperoxide (70%) (“t-BHP”) (4.7 g in 23 g DI water) and 2.8 g of sodium formaldehyde bisulfite in 28 g DI water, via two separate feeds over 25 minutes. Upon completion of the feeds, the reaction is cooled to room temperature. The obtained acrylic dispersion 1 is then filtered through 325 mesh filter cloth to prepare the composition for subsequent evaluation work. The obtained acrylic dispersion 1 includes an acrylic-based polymer composed of 71.5 wt % 2-EHA/18.5 wt% EA/9 wt% MMA/1 wt% AA, and has a glass transition temperature of -41° C. Weight percent is based on the total dry weight of the acrylic-based polymer.

B. Acrylic Dispersion 2

[0125] Acrylic Dispersion 2 is INVISU™ 4100 available from The Dow Chemical Company.

C. Acrylic Dispersion 3

[0126] Acrylic Dispersion 3 is INVISU™ 3000 available from The Dow Chemical Company.

D. Acrylic Dispersion 4

[0127] A flask set up for semi-continuous emulsion polymerization containing 270 g of water at 90° C. was charged first with sodium peroxodisulfate (1.26 g) in 13 g deionized water and second with 21.2 g of a seed consisting of an aqueous dispersion of an acrylic polymer with mean particle diameter 60 nm at 12% solids content. After two minutes, addition of a feed stream containing sodium peroxodisulfate (3.79 g) in 59.8 g deionized water and a monomer emulsion was begun and continued at a constant rate over 120 minutes at 90° C. The monomer emulsion consisted of 1250 g of monomers in proportions by weight according to Table 2, 180 g of a 33% concentration solution of a sulfuric ester sodium salt of lauryl alcohol ethoxylated by 30 moles of ethylene oxide in water, 5.6 g of a 44% strength solution of DOWFAX™ 2A1 in water, 6.7 g of a 75% concentration solution of dioctylsulfosuccinate sodium salt in ethanol/water, and 295 g of deionized water. After half of the weight of the monomer emulsion was added to the reactor, 72 g of a seed consisting of an aqueous dispersion of an acrylic polymer with mean particle diameter 60 nm at 26% solids content was charged to the reactor within one minute. After the monomer emulsion and the feed stream were fully added to the reactor, an additional 35 g of deionized water was added while the reactor temperature was maintained at 90° C. Next, ammonia (17.9 g of 4.4% concentration in water) was added to the reactor. Finally, a solution of 8% tert-butyl hydroperoxide in water (23 g) and a solution of 10% sodium formaldehyde sulfoxylate in water (19.5 g) were added to the reactor at 90° C. at a constant rate over 60 minutes. After the completion of these feed streams, the reactor contents were cooled to room temperature.

E. Acrylic Dispersion 5

[0128] Using a flask equipped with a mechanical stirrer, an initial aqueous charge composed of 0.51 grams tetrasodium pyrophosphate, 640 grams of deionized water, 1.80 grams anhydrous sodium sulfate, and 1.36 grams ascorbic acid is warmed to 87° C. Next, 28.4 grams of 19% concentration sodium persulfate in water is poured into the flask. Over a period of 2.0 hours, an emulsion made up of 14.7 grams of 50% strength aqueous sodium hydroxide solution, 39.4 grams of a 30% concentration solution of a sulfuric ester sodium salt of lauryl alcohol ethoxylated by 12 moles of ethylene oxide in water, 21.2 grams of 25.0% concentration sodium vinyl sulfonate solution in water, 28.8 grams of a 22% strength solution of sodium dodecylbenzene sulfonate in water, 6.6 grams of itaconic acid, 236 grams of water, 321.2 grams of methyl methacrylate, 55.2 grams of styrene, 1,592.4 grams of 2-ethylhexyl acrylate, 679.3 grams of ethyl acrylate, and 14.4 grams of acrylic acid is gradually fed into the flask. At the outset, the rate of addition is 5.0 grams per minute for the first 5.0 minutes. It is then raised steadily to 25.0 grams per minute over the span of 35 minutes. After 75 minutes of total feed time, the rate is raised to 35.0 grams per minute. From the outset of the emulsion feed, 94 grams of a sodium peroxodisulfate solution at 11% strength in water is added at a constant rate over 2.3 hours, and the reactor temperature is kept at 85 to 87° C.

[0129] After the completion of the feeds and at roughly 70° C., a solution of 2.76 grams sodium bisulphite, 1.8 grams acetone and 44.4 grams water, and, at the same time, 47.6 grams of a 5.5% concentration solution of tert-butyl hydroperoxide is dispensed to the flask over a period of 45 minutes. A copolymer dispersion of pressure-sensitive adhesive is produced with 70% solids by weight.

F. Acrylic Dispersion 6

[0130] Using a flask equipped with a mechanical stirrer, a charge composed of 1.34 g tetrasodium pyrophosphate, 269 g of deionized water, and 0.68 g ascorbic acid is warmed to 86° C. Next, 28 g of 6.6% concentration sodium persulfate in water is poured into the flask. Over a span of four hours, an emulsion made up of 24.5 g of 10% strength aqueous sodium hydroxide solution, 30 g of a 33% concentration solution of a sulfuric ester sodium salt of lauryl alcohol ethoxylated by 30 moles of ethylene oxide in water, 10.6 g of 25.0% concentration sodium vinylsulfonate solution in water, 5 g of a 44% strength solution of DOWFAX™ 2A1 in water, 2.2 g of lauryl alcohol ethoxylated with 7 mol of ethylene oxide, 172 g of water, 27.6 g of styrene, 1,079.2 g of 2-ethylhexyl acrylate, 55.2 g of vinyl acetate, 162 g of methyl methacrylate, and 7.2 g of acrylic acid is gradually dispensed into the flask. At the outset, the rate of addition is 1.42 g/minute for the first six minutes. The rate of addition is then raised steadily to 7.1 g/minute over the span of forty minutes. From the outset of the emulsion feed, 148 g of a sodium peroxodisulfate solution at 5% strength in water is added at a constant rate over five hours, and the reaction medium is maintained from 85 to 87° C.

[0131] After the completion of the feeds and at roughly 70° C., a solution of 1.38 g sodium bisulphite, 0.9 g acetone and 22.2 g water, and, at the same time, 23.8 g of a 5.5% concentration solution of tert-butyl hydroperoxide is dispensed to the flask during the span of sixty minutes.

G. Acrylic Dispersion 7

[0132] Sodium carbonate (0.01% BOM, 0.55 g) was added as buffer to a 96° C. kettle charge of a water (518 g) swept with nitrogen, equipped with overhead stirring, thermometer, and reflux condenser. This was followed by ammonium persulfate (0.217% BOM, 5.9 g) as initiator and a preform seed charge (100 nm starting particle size, 1.251% BOM, 70.79 g) to set the initial particle size. A monomer emulsion feed and cofeed were started. The monomer emulsion consisted of sodium carbonate (0.02% BOM, 1.4 g), itaconic acid (0.2%, 5.1 g), acrylic acid (0.8% BOM, 20.4 g), disodium ethoxylated alcohol half ester of sulfosuccinic acid (0.17%, 14.3 g), sodium dodecylbenzenesulfonate (0.21% BOM, 24.2 g), butyl acrylate (71.1% BOM, 1818 g), methyl methacrylate (6.0% BOM, 152.8 g), styrene (1.6% BOM, 40.8 g) and water (16.8% of total monomer emulsion, 4 1lg) and was fed for 75 minutes. The co-feed of ammonium persulfate (0.173% BOM, 4.6 g) was fed for 75 minutes. The temperature of the reaction was controlled between 88-90° C. Partway through the monomer emulsion feed an intercept of sodium dodecylbenzenesulfonate (0.235% BOM, 26.5 g) was added to the kettle. Once the addition of the monomer emulsion concluded, it was held at temperature. After fifteen minutes the kettle was cooled to 75° C. and dilute iron sulfate (0.001%BOM, 0.03 g) and tetrasodium ethylenediaminetetraacetate (0.001%BOM, 0.03 g) was added to the kettle. Subsequently a monomer emulsion feed and cofeeds were started. The monomer emulsion consisted of tetrasodium 1,1-diphosphonatoethanol (0.002%, 0.1 g), acetic acid (0.03%BOM, 0.6 g), sodium dodecylbenzenesulfonate (0.05% BOM, 5.3 g), butyl acrylate (5%BOM, 127.8 g), butyl methacrylate (15% BOM, 353.3 g), 3-methylmercaptopropionate (0.38%BOM, 9.8 g) and water (105.7 g) for 20 minutes. One cofeed consisted of t-butlyhydroperoxide (0.4% BOM, 15.1 g) and was fed for 50 minutes. The other cofeed consisted of sodium hydroxymethanesulfonate (0.24%BOM, 8.1 g) and was fed for 50 minutes. During the monomer emulsion feed the temperature was controlled at 74-76° C. Once the monomer emulsion finished, the batch was allowed to cool to 65° C. The dispersion was then neutralized with ammonium hydroxide until a pH of 7 was obtained. After neutralization the batch was cooled to below 35° C.

[0133] Table 2 below summarizes the properties for acrylic dispersions 1-7 where component amounts are shown as weight percent based on dry weight of the acrylic dispersion.

TABLE-US-00004 Acrylic dispersions composition and properties Component Acrylic Dispersion 1 Acrylic Dispersion 2 Acrylic Dispersion 3 Acrylic Dispersion 4 Acrylic Dispersion 5 Acrylic Dispersion 6 Acrylic Dispersion 7 2-EHA 71.5 80 59.5 80.9 - MA - 8 - - - MMA 9 8 12.0 12.1 6.0 Styrene - 2 2.1 2.1 1.6 2-hydroxyethyl acrylate - 1 - - - AA 1 1 0.55 0.55 0.8 BA - 0 - - 76.1 EA 18.5 0 25.4 - Itaconic acid - - 0.2 - 0.2 Component Acrylic Dispersion 1 Acrylic Dispersion 2 Acrylic Dispersion 3 Acrylic Dispersion 4 Acrylic Dispersion 5 Acrylic Dispersion 6 Acrylic Dispersion 7 Sodium vinyl sulfonate - - 0.25 0.25 - VA - - - 4.1 - n-butyl methacrylate - - - - 15 Property pH 7.5 7.75 4.75 6.1 4.5 4.2 7.0 Solids (%) 66.4 62 68 61 70 66 64 Viscosity (cP) - 1000 - - - - - Tg -41° C. -45° C. -53° C. -40° C. -33° C. -46 -26° C. Wt% based on dry weight of acrylic dispersion

2. Preparation of Ethylene Ester Dispersion

[0134] Aqueous ethylene ester dispersions EEP1-8 were prepared utilizing a Bersdorf ZE25 48 L/D 25 mm twin screw extruder (Kraus-Maffei Corporation, Florence KY, USA) rotating at 450 rpm according to the following procedure. The ethylene ester polymer (EEP feed 1 in Table 3 below) was supplied to the feed throat of the extruder via a Schenck Mechatron loss-in-weight feeder and additional resins (Resin Feed 2) were added via K-tron loss in weight feeders to control blend composition. The EEP resin and any addtives were melt blended, and then emulsified in the presence of initial aqueous stream (IA) and a dispersant, neutralized if applicable with potassium hydroxide (KOH) or dimethylethanolamine, both injected using ISCO dual syringe pumps (from Teledyne Isco, Inc., Lincoln NE, USA). The dispersion phase was then conveyed forward to the dilution and cooling zone of the extruder where additional dilution water was added by ISCO dual syringe pumps to form the aqueous dispersion having solid level content less than 70 weight percent. The barrel temperature of the extruder was set to 140-150° C. After the ethylene ester dispersion exited the extruder, it was further cooled and filtered via a 200 .Math.m mesh size bag filter.

[0135] Specific feed rates and results are shown in Table 3 below.

TABLE-US-00005 Preparation parameters for ethylene ester dispersions made via continuous process Sample Description Resin Feed 1, g/min Resin Feed 2, g/min Dispersant, g/min IA, mL/min Neutralizing Base, mL/min Dilution Water, mL/min Vmean Particle size (.Math.m) EEP1 42% solids aqueous dispersion of AMPLIFY™ EA103 (65% by weight) co-dispersed with Licocene 4351 (10% by weight) and ­­­­­PRIMACOR™ 5980i (25% by weight) 49.1 7.6 PRIMACOR™ 5980i, 18.9 21.9 Dimethylethanolamine, 9.0 100 0.460 EEP2 95.5% ELVALOY™ AC 15024S 75.7 --- Oleic acid, 3.6 2.2 30% potassium hydroxide, 2.1 110 1.195 EEP3 95.5% ELVALOY™ AC 34035 75.7 --- Oleic acid, 3.6 2.5 30% potassium hydroxide, 2.1 110 1.406 EEP4 95.5% ELVALOY™ AC 1609 75.7 --- Oleic acid, 3.6 2.2 30% potassium hydroxide, 2.3 110 1.615 EEP5 86% ELVALOY™ AC 1609 / 9.5% Licocene 4351 68.1 7.6 Oleic acid, 3.6 1.0 30% potassium hydroxide, 3.4 110 0.497 EEP6 86% ELVALOY™ AC 3717/9.5% Licocene 4351 68.1 7.6 Oleic acid, 3.6 2.5 30% potassium hydroxide, 3.6 110 0.959 EEP7 84% ELVALOY™ AC1820 / 16% NUCREL™ 960 61.3 11.4 Oleic acid, 3.0 6.0 30% potassium hydroxide, 5.1 85 1.128 EEP8 ELVALOY™ AC3427 / 16% NUCREL™ 960 61.3 11.4 Oleic acid, 3.0 6.7 30% potassium hydroxide, 4.0 85 1.569

[0136] Aqueous ethylene ester dispersions EEP9-11 were prepared using a 2CV Helicone mixer (DIT), a jacketed conical batch mixer that uses dual intermeshing conical blades to mix high viscosity materials (max 12 MM cP). The unit incorporates a bottom discharge valve and the mixer blades can be used to extrude materials through the valve after mixing. The 2CV unit has a working volume of 50-250 mL. A large capacity re-circulation bath was connected to the mixing bowl jacket to heat the unit and an ISCO pump was used to inject dilution water into the system while mixing. In addition, the Helicone utilized a secondary oil pump to maintain constant pressure on the mechanical seals for the blade shafts to counterbalance pressure within the vessel.

[0137] The dispersions were made as described in Table 4. The resin, surfactant, base, and initial aqueous (IA) were loaded into the Helicone which was then pressurized to 70 psi under a nitrogen blanket and the heater was set to 140° C. After 30 minutes, the components had reached the prescribed temperature and were mixed for 30 minutes at 50 rpm to create the initial emulsion. Next, the impellers were increased to 100 rpm emulsion was diluted to 60% solids by adding deionized water at 1.5 mL/min, before diluting to the final target concentration of approximately 40% solids at 2.5 mL/min. After dilution, the mixing was stopped and the dispersion was allowed to cool for 30 min until it was below 80° C. at which point the Helicone was vented and the dispersion collected through the gate valve.

TABLE-US-00006 Preparation parameters for ethylene ester dispersions made via batch process Sample Description Resin Feed 1, g Resin Feed 2, g Dispersant, g IA, mL Neutralizing Base, mL Dilution Water, mL Vmean Particle size (.Math.m) EEP9 EER1/Pluronic F108 (90/10) 68.0 --- Pluronic F-108, 7.6 8.4 --- 104 1.771 EEP10 88% EER2/12% EMPICOL® ESB70 50.0 --- EMPICOL® ESB70, 6.9 2.3 50% sodium hydroxide, 0.75 75 0.501 EEP11 91% EER3/9% EMPICOL® ESB70 50.0 --- EMPICOL® ESB70, 6.3 13 50% sodium hydroxide, 0.6 60 3.986

3. Preparation of Pressure Sensitive Adhesive Composition

[0138] The water-based pressure sensitive adhesive composition was formulated as follows. All samples were formulated with a wetting agent, 0.3% (wet/wet) SURFYNOL 440 wetting agent obtained from Evonik (“440”), based on total dispersion, to improve wet-out for lab drawdowns unless otherwise specified. The viscosity was then adjusted to approximately 600 mPa.s (600 cps) (Brookfield, RVDV, 30 rpm, 63#) using a thickener, ACRYSOL™ DR-5500, available from Dow, Inc., Midland, Michigan (“DR-5500”), and final pH was adjusted to 7.0 to 7.5 using ammonium hydroxide.

[0139] The acrylic dispersion was blended with the ethylene ester dispersion according to the dosage level shown in the respective table (wet or dry weight based on total weight of acrylic dispersion) under proper agitation.

4. Preparation of PSA Article

Lab Drawdowns:

[0140] Polypropylene (“PP”) film (60 microns in thickness) was pre-treated by corona treatment before lamination. Samples of the water-based PSA composition were coated onto a release paper and dried at 80° C. for 5 minutes. The PP film was laminated with the water-based pressure-sensitive adhesive coated release liner (“adhesive laminate”).

[0141] Performance testing was conducted after the adhesive laminate was conditioned in a controlled environment (22.2 to 23.3° C. (72 to 74° F.), 50% relative humidity) for at least 1 day (24 hours).

[0142] High density polyethylene (HDPE) panels purchased from Cheminstruments (510 Commercial Dr., West Chester Township, OH 45014) are cleaned and conditioned prior to being used for adhesive testing. Panels are wiped with lint-free, non-abrasive cloth soaked in isopropanol to remove any adhesive residue from prior testing. Care is taken not to scratch the surface. Once panel surface appears clean, an additional wipe is performed using isopropanol. The HDPE panel is conditioned for a minimum of 4 hours but no more than 24 hours at 22.2 to 23.3° C. (72 to 74° F.), 50% relative humidity.

5. PSA Application Tests Evaluating EEP1

[0143] Performance testing was conducted after the water-based PSA composition in the adhesive laminate was completely dried and conditioned in a controlled environment (22.2 to 23.3° C., 50% relative humidity) testing laboratory for at least overnight, and in some instances after as many as 120 hours under 12 kg of weight.

[0144] The peel adhesion, loop tack, and shear data for adhesive laminates with the dried PSA compositions composed of (i) acrylic dispersion 2 and (ii) ethylene ester dispersion are provided in Table 5 to Table 7 below.

TABLE-US-00007 Peel adhesion, loop tack, and shear data for adhesive laminates with dried PSA compositions. Acrylic dispersion 2 (parts by wet weight) Additive (Parts by dry Weight) Additive (dry wt %) 90° Peel HDPE, N/2.54 cm, 20 min 90° Peel HDPE, N/2.54 cm, 24 hr Loop Tack SS, N/6.45 cm.sup.2 Loop Tack HDPE, N/6.45 cm.sup.2 Shear, SS, h CS1 100 0 0 2.8 4.0 10.3 5.7 25 IE1 100 EEP1 (0.4) 0.6 2.8 5.3 11.6 5.6 33 IE2 100 EEP1 (2.0) 3.1 3.7 5.1 11.1 5.6 37 CS - comparative sample, IE - inventive example

[0145] The 90° HDPE peel adhesion (24 hr and 20 min) observed for PSA articles (laminates) prepared from formulations of acrylic dispersion 2 unexpectedly increases with the addition of EEP copolymer dispersions. CS1, which is void of an EEP copolymer dispersion, exhibits 90° HDPE peel adhesion (24 hr) of 4.0 N/in compared to IE2, which has 2 parts EEP1, that exhibits 90° HDPE peel adhesion (24 hr) of 5.1 N/in. Also unexpectedly, addition of less EEP1 (only 0.4 parts) actually increases 90° HDPE peel adhesion (24 hr) even more, to 5.3 N/in. Also unexpectedly, the addition of 2 parts EEP1 increased 90° HDPE peel adhesion (20 min), while the addition of only 0.4 parts EEP1 did not.

6. PSA Application Tests Evaluating EEP2, EEP3, EEP4, EEP5, and EEP6

[0146] The EEPs were formulated with Acrylic Dispersion 2 and PSA application tests were performed according to the methods described above.

TABLE-US-00008 Peel adhesion and loop tack data for adhesive laminates with dried PSA compositions. Acrylic dispersion 2 (parts by wet weight) Additive (Parts by Dry Weight) Additive (dry wt %) 90° Peel (HDPE), 20 min, N/2.54 cm 90° Peel (HDPE), 24 h, N/2.54 cm Loop Tack (HDPE), N CS2 100 0 0 3.9 4.2 6.4 IE3 100 EEP2 (0.4) 0.6 4.1 5.0 4.4 IE4 100 EEP2 (4) 6.0 4.2 4.7 4.9 IE5 100 EEP3 (0.4) 0.6 5.4 5.3 5.8 IE6 100 EEP3 (4) 6.0 4.5 4.5 4.8 IE7 100 EEP4 (0.4) 0.6 6.1 6.1 5.5 IE8 100 EEP4 (4) 6.0 4.9 5.1 6.2 IE9 100 EEP5 (0.4) 0.6 5.6 6.3 6.7 IE10 100 EEP5 (4) 6.0 5.5 5.6 5.7 IE11 100 EEP6 (0.4) 0. 5.2 5.4 4.8 IE12 100 EEP6 (4) 6.0 4.6 4.7 4.4

[0147] The 90° HDPE peel adhesion (24 hr and 20 min) observed for PSA articles (laminates) prepared from formulations of acrylic dispersion 2 unexpectedly increases with the addition of EEP copolymer dispersions. CS2, which is void of an EEP copolymer dispersion, exhibits 90° HDPE peel adhesion (20 min) of 3.9 N/2.54 cm compared to the inventive examples in this experiment which contain 0.4 to 4 parts of EEP, that exhibit 90° HDPE peel adhesion (20 min) of 4.1 to 5.6 N/2.54 cm. The same observation holds with 90° HDPE peel adhesion (24 h): all of the inventive examples containing EEP have higher adhesion when compared to CS2. 7. PSA Application Tests Evaluating EEP9

[0148] The EEP was formulated with Acrylic Dispersion 2 and PSA application tests were performed according to the methods described above.

TABLE-US-00009 Peel adhesion and loop tack data for adhesive laminates with dried PSA compositions. Acrylic dispersion 2 (parts by wet weight) Additive (Parts by Dry Weight) Additive (dry wt %) 90° Peel (HDPE), 20 min, N/2.54 cm 90° Peel (HDPE), 24 h, N/2.54 cm Loop Tack (HDPE), N CS2 100 0 0 4.7 5.1 5.0 IE13 100 EEP9 (0.4) 0.6 4.7 5.5 6.2 IE14 100 EEP9 (4) 6.0 4.9 5.3 6.6

[0149] The 90° HDPE peel adhesion and loop tack observed for PSA articles (laminates) prepared from formulations of acrylic dispersion 2 unexpectedly increases with the addition of EEP9 copolymer dispersions. CS2, which is void of an EEP copolymer dispersion, exhibits 90° HDPE peel adhesion (24 h) of 5.1 N/2.54 cm and loop tack of 5.0 N compared to the inventive examples in this experiment which contain 0.4 to 4 parts of EEP9, that exhibit 90° HDPE peel adhesion (24 h) of 5.3 to 5.5 N/2.54 cm and loop tack of 6.2 to 6.6 N.

8. Performance Testing of Formulations With EEP5 and EEP9 With Other Acrylic Dispersions

[0150] The acrylic dispersion was blended with the EMAA dispersion according to the dosage level shown in the respective table (wet weight based on total weight of acrylic dispersion) under proper agitation to achieve mixing.

TABLE-US-00010 Acrylic dispersion (parts by wet weight) EEP5 parts by dry weight EEP9 parts by dry weight Additive (dry wt %) IE15 Acrylic dispersion 3 (100) 1 1.6 IE16 Acrylic dispersion 3 (100) 1 1.6 IE17 Acrylic dispersion 4 (100) 1 1.6 IE18 Acrylic dispersion 4 (100) 1 1.6 IE19 Acrylic dispersion 5 (100) 1 1.6 IE20 Acrylic dispersion 5 (100) 1 1.6 IE21 Acrylic dispersion 6 (100) 1 1.6 IE22 Acrylic dispersion 6 (100) 1 1.6 IE23 Acrylic dispersion 7 (100) 1 1.6 IE24 Acrylic dispersion 7 (100) 1 1.6

9. PSA Application Tests Evaluating EEP7 and EEP8

[0151] The EEPs were formulated with Acrylic Dispersion 2 and PSA application tests were performed according to the methods described above.

TABLE-US-00011 Peel adhesion and loop tack data for adhesive laminates with dried PSA compositions. Acrylic dispersion 2 (parts by wet weight) Additive (Parts by Dry Weight) Additive (dry wt %) 90° Peel (HDPE), 20 min, N/2.54 cm 90° Peel (HDPE), 24 h, N/2.54 cm CS2 100 0 0 3.8 4.7 IE25 100 EEP7 (0.4) 0.6 4.4 5.1 IE26 100 EEP8 (0.4) 0.6 4.0 4.2

[0152] The 90° HDPE peel adhesion (20 min and 24 h) observed for PSA articles (laminates) prepared from formulations of acrylic dispersion 2 unexpectedly increases with the addition of EEP copolymer dispersions. CS2, which is void of an EEP copolymer dispersion, exhibits 90° HDPE peel adhesion (20 min) of 3.8 N/2.54 cm compared to the inventive examples in this experiment which contain 0.4 parts of EEP, that exhibit 90° HDPE peel adhesion (20 min) of 4.4 to 4.0 N/2.54 cm. The same observation holds with 90° HDPE peel adhesion at 24 h of IE25: this inventive example containing EEP has higher adhesion when compared to CS2.

10. PSA Application Tests Evaluating EEP10 and EEP11

[0153] The EEPs were formulated with Acrylic Dispersion 2 and PSA application tests were performed according to the methods described above.

TABLE-US-00012 Peel adhesion and loop tack data for adhesive laminates with dried PSA compositions. Acrylic dispersion 2 (parts by wet weight) Additive (Parts by Dry Weight) Additive (dry wt %) 90° Peel (HDPE), 20 min, N/2.54 cm 90° Peel (HDPE), 24 h, N/2.54 cm CS2 100 0 0 2.5 2.9 IE27 100 EEP10 (0.4) 0.6 2.6 3.2 IE28 100 EEP10 (2.0) 3 2.3 3.4 IE29 100 EEP11 (0.4) 0.6 2.5 3.5

[0154] The 90° HDPE peel adhesion (20 min and 24 h) observed for PSA articles (laminates) prepared from formulations of acrylic dispersion 2 unexpectedly increases with the addition of EEP copolymer dispersions. CS2, which is void of an EEP copolymer dispersion, exhibits 90° HDPE peel adhesion (24 h) of 2.9 N/2.54 cm compared to the inventive examples in this experiment which contain 0.4 to 2 parts of EEP, that exhibit 90° HDPE peel adhesion (24 h) of 3.2 to 3.5 N/2.54 cm. Hence, after the 24 h dwell time, the EEP copolymer dispersions unexpectedly increase the adhesion of the articles containing them.

[0155] 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.