Acrylic adhesive composition containing ethylene / ester copolymer

Abstract

The present disclosure relates to a water-based pressure-sensitive adhesive composition. In one embodiment, the water-based pressure-sensitive adhesive composition includes (A) an acrylic dispersion comprising particles of (i) an acrylic polymer having a glass transition temperature (Tg) of less than -20°C and (ii) a surfactant. The water-based pressure-sensitive adhesive composition also includes (B) an ethylene ester dispersion comprising (i) particles of an ethylene ester copolymer having 1% to less than 50% by weight of an acrylate comonomer and (ii) a dispersing agent. Articles comprising the water-based pressure-sensitive adhesive composition are also disclosed.

Description

[Background technology]

[0001] Pressure-sensitive adhesives (PSAs) are adhesives that bond to a substrate when pressure is applied. PSAs differ from adhesives that are activated by, for example, heat, irradiation, or chemical reactions. Typically, aqueous PSAs are applied to a substrate as an emulsion or dispersion and then dried to remove the liquid solvent.

[0002] Pressure-sensitive adhesives are typically characterized by their adhesiveness and cohesiveness. Adhesion is indicated by the peel strength and / or tackiness of the PSA to the substrate. Cohesiveness is indicated by the shear resistance of the PSA. Since there is an inverse correlation between adhesiveness and cohesiveness, PSAs with high adhesiveness have low cohesiveness, and PSAs with low adhesiveness have high cohesiveness.

[0003] However, certain adhesive applications require both high adhesion and high cohesiveness. It is known that adding tackifiers to acrylic PSAs enhances adhesion. However, typically, when added to acrylic PSAs, tackifiers reduce cohesiveness. Therefore, this technology recognizes the need for acrylic PSAs with increased cohesiveness without reducing adhesion. Furthermore, there is a need for acrylic PSA compositions that exhibit increased adhesion without reduced cohesiveness, without the use of tackifiers. [Overview of the project]

[0004] This disclosure relates to aqueous pressure-sensitive adhesive compositions. In one embodiment, the aqueous pressure-sensitive adhesive composition comprises an acrylic dispersion comprising (A) an acrylic dispersion comprising particles of (i) an acrylic polymer having a glass transition temperature (Tg) of less than -20°C and (ii) a surfactant. The aqueous pressure-sensitive adhesive composition also comprises an ethylene ester dispersion comprising (B) an ethylene ester dispersion comprising (i) particles of an ethylene ester copolymer having 1% to less than 50% by weight of an acrylate comonomer and (ii) a dispersant. Articles comprising aqueous pressure-sensitive adhesive compositions are also disclosed.

[0005] This disclosure provides articles. In one embodiment, the article comprises a first substrate and a layer of an aqueous pressure-sensitive adhesive composition on the first substrate. The aqueous pressure-sensitive adhesive composition comprises an acrylic dispersion comprising (A) an acrylic dispersion comprising particles of (i) an acrylic polymer having a glass transition temperature (Tg) of less than -20°C and (ii) a surfactant. The aqueous pressure-sensitive adhesive composition also comprises an ethylene ester dispersion comprising (B) an ethylene ester dispersion comprising particles of (i) an ethylene ester copolymer having 1% to less than 50% by weight of an acrylate comonomer and (ii) a dispersant. Articles comprising an aqueous pressure-sensitive adhesive composition are also further disclosed.

[0006] definition Any references to the periodic table refer to the edition published by CRC Press, Inc., 1990–1991. References to element groups in this table are based on a new notation for numbering groups.

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

[0008] The numerical ranges disclosed in this specification include all values from the lower limit to the upper limit, including the lower and upper limits. In the case of ranges containing explicit values (e.g., 1 or 2, or 3 to 5, or 6, or 7), any sub-range between any two explicit values is included (e.g., the range of 1 to 7 above includes sub-ranges such as 1 to 2, 2 to 6, 5 to 7, 3 to 7, 5 to 6, etc.).

[0009] Unless otherwise stated, implied by the context, or not customary in the art, all parts and percentages are by weight, and all test methods are the latest as of the filing date of this disclosure.

[0010] As used herein, "acrylic monomer" means the following:

[0011]

Chemical formula

[0012] As used herein, the term "blend" or "polymer blend" refers to a blend of two or more polymers. Such blends may or may not be miscible (not phase - separated at the molecular level). Such blends may or may not be phase - separated. Such blends may or may not contain one or more domain structures determined by transmission electron spectroscopy, light scattering, X - ray scattering, and other methods known in the art.

[0013] The term "composition" refers to a mixture of materials containing the composition, as well as reaction and decomposition products formed from the materials of the composition.

[0014] The terms “comprising,” “including,” and “having,” and their derivatives, are not intended to exclude the presence of any additional components, steps, or procedures, whether or not they are specifically disclosed. To avoid doubt, all compositions claimed through the use of the term “comprising” may include any additional additives, adjuvants, or compounds, whether polymers or otherwise, unless otherwise stated. In contrast, the term “essentially consisting of” excludes any other components, steps, or procedures from the scope of any subsequent description, except those not essential to the operability. The term “consisting of” excludes any components, steps, or procedures not explicitly described or enumerated. The term “or” refers to the enumerated members individually and in any combination, unless otherwise specified. The use of the singular includes the use of the plural, and vice versa.

[0015] An "ethylene-based polymer" is a polymer containing more than 50 weight percent (wt%) of polymerizable ethylene monomers (based on the total amount of polymerizable monomers) and optionally containing at least one comonomer. Ethylene-based polymers include ethylene monopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used synonymously.

[0016] An "olefin polymer" or "polyolefin" is a polymer containing more than 50 weight percent of polymerizable olefin monomers (based on the total amount of polymerizable monomers), and may optionally contain at least one comonomer. An unrestricted example of an olefin polymer is an ethylene polymer.

[0017] A “polymer” is a compound prepared by polymerizing monomers that provide multiple and / or repeating “units” or “mer units” that constitute a polymer in polymeric form, whether of the same or different types. Therefore, the general term polymer encompasses both the term homopolymer, commonly used to refer to polymers prepared from only one type of monomer, and the term copolymer, commonly used to refer to polymers prepared from at least two types of monomers. It also encompasses all forms of copolymers, such as random, block, etc. The terms “ethylene / α-olefin polymer” and “propylene / α-olefin polymer” refer to the aforementioned copolymers prepared by polymerizing ethylene or propylene with one or more additional polymerizable α-olefin monomers, respectively. While polymers are often described as “made from” one or more specific monomers, “based on” a specific monomer or monomer type, and “containing” a specific monomer content, etc., it should be noted that in this context, the term “monomer” is understood to refer to the polymerized residue of a specific monomer, and not to the non-polymerized species. In general, polymers in this specification are referred to as "units," which are the polymerized forms of the corresponding monomers.

[0018] A “propylene polymer” is a polymer containing more than 50 weight percent of polymerizable propylene monomer (based on the total amount of polymerizable monomers), and may optionally contain at least one comonomer. Propylene polymers include propylene homopolymers and propylene copolymers (meaning units derived from propylene and one or more comonomers). The terms “propylene polymer” and “polypropylene” may be used interchangeably. Non-limiting examples of suitable propylene copolymers include propylene impact copolymers and propylene random copolymers.

[0019] Test method Adhesion / Tackiness Test: Samples are tested on both stainless steel ("SS") and high-density polyethylene (HDPE) test plates according to the Federation Internationale des fabricants et transformateurs d'Adhesives et Thermocollants ("FINAT") Test Method No. 2. Cohesion / Shear Test: For shear resistance testing of stainless steel plates, FINAT Test Method No. 8 is used. Failure characteristics are recorded after the test value: "AF" indicates poor adhesion. "AFB" indicates poor adhesion from the backing material, i.e., the release liner. "CF" indicates poor cohesion. "MF" indicates poor mixing. Peel Strength Test: For the 90° peel strength test on high-density polyethylene (HDPE) test plates, FINAT Test Method No. 2 was followed. FINAT is the European association for the self-adhesive label industry (Laan van Nieuw-Oost Indie131-G, 2593 BM The Hague, POBox 85612, 2508 CH The Hague, The Netherlands). Before testing, sample pieces were applied to test plates with a residence time of 20 minutes.

[0020] The density is measured according to ASTM D792, Method B. The results are recorded in grams per cubic centimeter (g / cc).

[0021] Differential Scanning Calorimetry (DSC) Differential scanning calorimetry (DSC) can be used to measure the melting, crystallization, and glass transition behavior of polymers over a wide range of temperatures. For example, this analysis is performed using a TA Instruments Q1000DSC equipped with an RCS (refrigerated cooling system) and an autosampler. A nitrogen purge gas flow rate of 50 mL / min is used during the test. Each sample is melted and compressed into a thin film at approximately 175°C, and then the molten sample is air-cooled to room temperature (approximately 25°C). Test specimens of 3–10 mg, 6 mm in diameter are extracted from the cooled polymer, weighed, placed in a lightweight aluminum pan (approximately 50 mg), and pressed shut. Analysis is then performed to determine its thermal properties.

[0022] The thermal behavior of the sample is determined by raising and lowering the sample temperature to create a heat flow versus temperature profile. First, to remove its thermal history, the sample is rapidly heated to 180°C and held isothermally for 3 minutes. Next, the sample is cooled to -40°C at a cooling rate of 10°C / min and held isothermally at -40°C for 3 minutes. Then, the sample is heated to 180°C at a heating rate of 10°C / min (this is the "second heating" gradient). The cooling curve and the second heating curve are recorded. The cooling curve is analyzed by setting the baseline endpoint at -20°C from the start of crystallization. The heating curve is analyzed by setting the baseline endpoint from -20°C to the end of melting. The values ​​to be obtained are the extrapolated melting start point Tm and the extrapolated crystallization start point Tc. Heat of fusion (H f Crystallinity % of polyethylene samples is calculated using the following formula: (Joules / gram), and crystallinity % = ((H f ) / 292J / g)x100

[0023] From the second heating curve, the heat of fusion (H f We report the enthalpy of melting (also known as the melting enthalpy) and the peak melting temperature.

[0024] The melting point Tm is first determined from the DSC heating curve by drawing a baseline between the start and end of the melting transition. Next, a tangent line is drawn to the data on the lower temperature side of the melting peak. The point where this line intersects the baseline is the extrapolated melting start point (Tm). This is as described in Bernhard Wunderlich, The Basis of Thermal Analysis, in Thermal Characterization of Polymeric Materials 92, 277-278 (Edith A. Turi ed., 2d ed. 1997).

[0025] The glass transition temperature (Tg) is determined from the DSC heating curve, as described in Bernhard Wunderlich, *The Basis of Thermal Analysis, in Thermal Characterization of Polymeric Materials* 92, 278-279 (Edith A. Turi ed., 2d ed. 1997), where half of the sample has acquired the heat capacity of a liquid. Baselines are drawn below and above the glass transition region and extrapolated through the Tg region. The temperature at which the heat capacity of the sample is midway between these baselines is Tg.

[0026] The loop tack test (PSTC Test Method 16) (Pressure Sensitive Tape Council, One Parkview Plaza, Suite 800, Oakbrook Terrace, IL 60101, USA) was performed as follows. The loop tack test measures the initial adhesive strength when the adhesive comes into contact with the substrate. The adhesive laminate was conditioned in a controlled environment (22.2–23.3°C (72–74°F), 50% relative humidity) for at least one day before being tested. A 2.54 cm (1 inch) wide test piece was cut and folded to form a loop, exposing the adhesive surface. This was then mounted between the jaws of an Instron® tensile testing machine, and the lower jaw was lowered against the substrate at a speed of 12 inches / min so that a 2.54 cm × 2.54 cm (1 inch × 1 inch) square area of ​​adhesive was in contact with the substrate for 1 second. The adhesive was then peeled off, and the peak force required to peel the adhesive from the substrate was recorded.

[0027] The melt index (MI)(I2) was measured at g / 10 min using ASTM D1238 (190℃ / 2.16kg).

[0028] The melt flow rate (MFR) is measured at g / 10 min using ASTM D1238 (230℃ / 2.16kg).

[0029] The melt viscosity at 140°C is measured using a Brookfield viscosity model and a Brookfield RV-DV-II-Pro viscometer spindle 31. The sample is poured into the chamber, then inserted into the Brookfield Thermosel and secured in place. The sample chamber has a notch at the bottom that fits into the bottom of the Brookfield Thermosel to ensure that the chamber does not rotate when the spindle is inserted and rotating. The sample (approximately 8-10 grams of resin) is heated to the required temperature until the molten sample is about 1 inch below the top of the sample chamber. The viscometer device is lowered, and the spindle is immersed in the sample chamber. The lowering is continued until the viscometer bracket and thermocell are aligned. The viscometer is powered on and set to operate at a shear rate that yields torque readings within 40-60 percent of the total torque capacity, based on the viscometer's rpm output. A reading is taken every minute for 15 minutes, or until the value stabilizes, and the final reading at that point is recorded.

[0030] Measure the emulsion viscosity or dispersion viscosity at 25°C using the Brookfield viscosity model and Brookfield RV-DV-II-Pro viscometer spindle #2 or #3. Pour the sample into a wide-mouth cup, pouring enough so that the spindle is completely submerged in the dispersion when the viscometer instrument is lowered. Start the viscometer and set it to operate at a shear rate of 12 RPM, 30 RPM, or 60 RPM. Observe the readings for 15 minutes, or until the values ​​stabilize, and record the final reading at that point.

[0031] Molecular weight is determined using gel permeation chromatography (GPC) on a Waters high-temperature chromatography unit at 150°C, equipped with three mixed porous columns (Polymer Laboratories 103, 104, 105, and 106) operating at a system temperature of 140°C. The solvent is 1,2,4-trichlorobenzene, from which a solution of approximately 0.3 wt% of the sample for injection is prepared. The flow rate is 1.0 mL / min, and the injection size is 100 microliters.

[0032] The molecular weight is estimated by using narrow molecular weight distribution polystyrene standards (from Polymer Laboratories) in combination with their elution volumes. The equivalent polypropylene molecular weight is determined using the appropriate Mark-Houwink coefficients for polyethylene and polypropylene (described in T. Williams & I. M. Ward, The Construction of a Polyethylene Calibration Curve for Gel Permeation Chromatography Using Polystyrene Fractions, 6 J. Polymer Sci. Pt. B: Polymer Letter 621, 621 - 624 (1968)) and the following equation: M polyethylene = a × (M polystyrene) b is derived. In this equation, a = 0.4316 and b = 1.0.

[0033] The number average molecular weight of the polymer, Mn, is expressed as the sum average of the plot of the number of molecules within each molecular weight range against the molecular weight. In practice, this is the total molecular weight of all molecules divided by the number of molecules, and the following equation: Mn = Σn i * M i / (Σn I ) = (Σw i ) / (Σ(w i / (M i ))) (where n i = the number of molecules having molecular weight M i and w i = the weight fraction of the material having molecular weight M i and Σn i = the total number of molecules) is calculated in the usual way. The weight average molecular weight, M W is given by the following equation: M W = Σw i * M iIt is calculated in the usual way according to the formula, where w i and M i These are the weight fraction and molecular weight of the i-th fraction eluted from the GPC column, respectively. The molecular weight distribution (MWD or M) is the ratio of the averages of these two. w / M n ) is used herein to define the width of the molecular weight distribution.

[0034] The Vicat softening point is measured according to ASTM D1525.

[0035] Volume-averaged particle size analysis is performed using a standard procedure with a Beckman Coulter LS13320 laser light scattering particle size analyzer (Beckman Coulter Inc., Fullerton, California), and the results are recorded in microns. [Modes for carrying out the invention]

[0036] This disclosure relates to aqueous pressure-sensitive adhesive compositions. In one embodiment, the aqueous pressure-sensitive adhesive composition comprises (A) an acrylic dispersion, which comprises particles of (i) an acrylic polymer having a glass transition temperature (Tg) of less than -20°C and (ii) a surfactant. The aqueous pressure-sensitive adhesive composition also comprises (B) an ethylene ester dispersion. The ethylene ester dispersion comprises (i) an ethylene / ester polymer (EEP) and (ii) a dispersant. The EEP contains 1% to less than 50% by weight of an acrylate comonomer, which is in particulate form.

[0037] A. Acrylic dispersion The aqueous PSA composition contains an acrylic dispersion. The term "aqueous PSA composition" refers to a pressure-sensitive adhesive composition in which water is the continuous phase, i.e., the aqueous medium. The acrylic dispersion contains, in addition to the ethylene polymer, one or more acrylic monomers, a surfactant, and water. The surfactant acts as an emulsifier, thereby enabling the formation of droplets of the hydrophobic acrylic monomer throughout the aqueous medium. Next, an initiator is introduced into the emulsified mixture. The initiator reacts with the one or more acrylic monomers dispersed throughout the aqueous medium until all or substantially all of the one or more acrylic monomers are polymerized. The final result is an acrylic dispersion consisting of dispersions of acrylic polymer particles in an aqueous medium, where the acrylic polymer particles consist of one or more acrylic monomer subunits in addition to the ethylene polymer.

[0038] The Tg of the acrylic polymer is below -20°C, or between -80°C and -20°C, or between -70°C and -30°C, or between -60°C and -40°C, and the Mw is greater than 100,000 Daltons and up to 10,000,000 Daltons. Non-limiting examples of suitable acrylic 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 12 ~C 18 Examples include alkyl methacrylate, cyclohexyl methacrylate, methacrylic acid, and combinations thereof. In addition to acrylic monomers, acrylic polymers may also contain monomers such as 2-hydroxyethyl acrylate (2-HEA), styrene (STY), vinyl esters, vinyl acetate, and combinations thereof.

[0039] Acrylic dispersions contain surfactants. Non-limiting examples of suitable surfactants include cationic surfactants, anionic surfactants, zwitterionic surfactants, nonionic 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 nonionic surfactants include, but are not limited to, block copolymers containing ethylene oxide, and silicone surfactants such as ethoxylated alcohols, ethoxylated fatty acids, sorbitan derivatives, lanolin derivatives, ethoxylated nonylphenol, or alkoxylated polysiloxanes. Suitable commercially available surfactants include, but are not limited to, surfactants sold by Dow Chemical Company under the commercial names TERGITOL® 15-S-9 and DOWFAX® 2A1, as well as products sold by BASF under the commercial name DISPONI, such as DISPONIL FES 77 IS and DISPONIL FES 993.

[0040] The initiator may be either a thermal initiator or a redox initiator. Examples of thermal initiators include, but are not limited to, ammonium persulfate, sodium persulfate, and potassium persulfate. When the initiator is a redox initiator, the reducing agent may be, for example, ascorbic acid, sulfoxylic acid, or erythorbic acid, while the oxidizing agent may be, for example, a peroxide or persulfate.

[0041] In one embodiment, the acrylic dispersion has the following properties: (i) subunits of two or more monomers selected from any combination of 2-EHA, MA, MMA, STY, 2-HEA, AA, BA, EA, VA, and BMA; and (ii) Contains particles of an acrylic polymer having a Tg of -60℃ to -30℃.

[0042] In one embodiment, the acrylic dispersion has the following properties: (i) monomer subunits from 2-EHA, EA, MMA, and AA; and (ii) Contains particles of an acrylic polymer having a Tg of -60℃ to -30℃.

[0043] In one embodiment, the acrylic dispersion has the following properties: (i) monomer subunits from among 2-EHA, MMA, STY, 2-HEA, AA, and BA; and (ii) Contains particles of an acrylic polymer having a Tg of -60℃ to -30℃.

[0044] B. Ethylene ester dispersion The aqueous PSA composition contains an ethylene ester dispersion. The ethylene ester dispersion contains ethylene / ester polymer (EEP) particles, a dispersant, and water. The ethylene / ester polymer consists of (i) ethylene, (ii) acrylate comonomer, and (iii) one or more termonomers as needed. The EEP contains more than 50% by weight of ethylene monomer and 1% to less than 50% by weight of acrylate comonomer. The weight percentage is based on the total weight of the EEP.

[0045] As used herein, “ethylene / ester polymer” (synonymous with “EEP”) is an ethylene-based polymer comprising (i) ethylene and (ii) an acrylate-based comonomer and (iii) optionally one or more termonomers. The acrylate-based comonomers are acrylic monomers, and include the following:

[0046] [ka] In the formula, R1 is C1-C 18The structure (I) is an alkoxy group, where R2 is a hydrogen or methyl group. The R1 group may be functionalized with 1 to 3 moieties, such as hydroxy, alkoxy, and oxirane. Acrylate comonomers include acrylates and methacrylates.

[0047] Ethylene / ester polymers are ethylene-based polymers (containing more than 50% by weight of ethylene-derived units) and are therefore different from acrylic polymers in acrylic dispersions. Ethylene / ester polymers are ethylene-based polymers (containing more than 50% by weight of ethylene-derived units) and exist without containing ethylene / ester copolymers prepared by emulsion polymerization in water.

[0048] In one embodiment, the ethylene ester dispersion contains EEP particles consisting of (i) ethylene, (ii) 10% to less than 50% by weight of an acrylate comonomer, and (iii) optionally one or more ter monomers. It is understood that the EEP particles are different from the acrylic polymer particles present in the acrylic dispersion. Non-limiting examples of suitable ter monomers include C3-C 12 Examples include α-olefins, acrylates / methacrylates (different from acrylate-based comonomers), glycidyl methacrylate, vinyl acetate, acrylic acid, and methacrylic acid. If present, the amount of ter monomer in EEP is greater than 0% to less than 30% by weight, or 1% to 10% by weight, or 3% to more than 8% by weight, based on the total weight percentage of EEP. If ter monomers are present, it is understood that the sum of the total weight percentages of (i) units derived from ethylene, (ii) units derived from acrylate-based comonomers, and (iii) units derived from ter polymers reaches 100% by weight of EEP.

[0049] The melt index (MI) for EEP is 1.0g / 10 min to 600g / 10 min, or 1.0g / 10 min to 125g / 10 min, or 5.0g / 10 min to 60g / 10 min, or 6.0g / 10 min to 50g / 10 min.

[0050] The density of EEP is 0.90 g / cc to 0.980 g / cc, or 0.920 g / cc to 0.950 g / cc, or 0.924 g / cc to 0.950 g / cc.

[0051] The melting point Tm of EEP is 70°C to 110°C, or 80°C to 105°C, or 82°C to 101°C.

[0052] The Vicat softening point of EEP is 40°C to 80°C, or 45°C to 75°C, or 49°C to 70°C.

[0053] EEP refers to the particle shape, where the volume-average particle size is 0.1 microns to 4.0 microns, or 0.3 microns to 1.9 microns, or 0.4 microns to 1.8 microns.

[0054] In one embodiment, EEP is an ethylene copolymer comprising (i) ethylene and (ii) acrylate comonomer. EEP contains 1% to less than 50% by weight, or 5% to 40% by weight, or 9% to 35% by weight of acrylate comonomer. The weight percentage is based on the total weight of EEP.

[0055] In one embodiment, the ethylene ester dispersion contains particles of EEP consisting of (i) ethylene and (ii) an acrylate having a C1-C8 alkoxy group or a C1-C4 alkoxy group, and has the following characteristics: (i) an acrylate comonomer content of 5-40% by weight, or 9-35% by weight; and / or (ii) Volume-average particle size of 0.1 to 2.0 microns, or 0.3 to 1.9 microns; and / or (iii) Melt index (MI) of 1.0 to 125 g / 10 min or 6.0 to 50 g / 10 min; and / or (iv) Density of 0.920 to 0.960 g / cc, or 0.924 to 0.944 g / cc; and / or (v) Melting point Tm of 70-110°C or 88-101°C; and / or (vi) Having one, some, or all of the following properties: a Vicat softening point of 40-80°C or 49-70°C.

[0056] In one embodiment, the ethylene ester dispersion contains particles of EEP consisting of (i) ethylene, (ii) acrylate comonomer, and (iii) acrylate-based termonomer (different from acrylate-based comonomer) or vinyl acetate, and has the following properties: (i) an acrylate comonomer content of 1% to 20% by weight, or 4% to 10% by weight; and / or (ii) an acrylate monomer content of 5% to 40% by weight, or 15% to 30% by weight; and / or (ii) Volume-average particle size of 0.1 to 2.0 microns, or 0.3 to 1.9 microns; and / or (iii) Melt index (MI) of 1.0-20 g / 10 min or 5.0-10 g / 10 min; and / or (iv) Density of 0.90 to 0.980 g / cc, or 0.3 to 0.96 g / cc; and / or (v) Having one, some, or all of the following properties: melting point Tm of 70°C to 90°C, or 80°C to 85°C.

[0057] Suitable commercially available 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, all available from Dow Inc.

[0058] The ethylene ester dispersion contains a dispersant. The dispersant provides colloidal stability of EEP in the ethylene ester dispersion. The dispersant is selected from long-chain fatty acids having 14 to 40 carbon atoms, anionic surfactants, cationic surfactants, nonionic surfactants, polyethylene having acidic functional groups, polypropylene having acidic functional groups, polyethylene / polypropylene block copolymers, and combinations thereof. In one embodiment, the dispersant is a long-chain fatty acid having 14 to 40 carbon atoms, or 16 to 36 carbon atoms, or 18 to 24 carbon atoms. The dispersant may be neutralized with a base such as potassium hydroxide, sodium hydroxide and / or dimethylethanolamine as needed. Non-limiting examples of long-chain fatty acids suitable as dispersants include lauric acid (C 12 ), palmitic acid (C 16 ), oleic acid (C 18 ), stearic acid (C 18 ), arachidic acid (C 20 ), euric acid (C 22 ), behenic acid (C 22 ) and combinations thereof are examples.

[0059] In one embodiment, the dispersant is an anionic surfactant. Non-limiting examples of anionic surfactants suitable as dispersants include sodium lauryl ether sulfonate, sodium dodecylbenzenesulfonate, and C 14 -C 16 Examples include sodium α-olefin sulfonate and DOWFAX® 2A1, available from Dow Inc.

[0060] In one embodiment, the dispersant is a cationic surfactant. A non-limiting example of a cationic surfactant suitable as a dispersant is stearamidopropyldimethylamine.

[0061] In one embodiment, the dispersant is a nonionic surfactant. Non-limiting examples of nonionic surfactants suitable as dispersants include poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) and poly(ethylene glycol)(PEG-PPG-PEG) alkyl ethers.

[0062] In one embodiment, the dispersant is polyethylene or polypropylene having an acidic functional group. Non-limiting examples of polyethylene or polypropylene having an acidic functional group include ethylene copolymers with acrylic acid, methacrylic acid, maleic acid, or maleic anhydride.

[0063] In one embodiment, the dispersant is an ethylene acid copolymer. As used herein, "ethylene acid copolymer" (synonymously referred to as "EAC") refers to copolymerized comonomers of (a) ethylene; (b) at least one C3-C8α,β ethylenically unsaturated carboxylic acid in an amount of 3% to less than 50% by weight; and optionally (c) at least one C3-C8α,β ethylenically unsaturated carboxylic acid ester in an amount of 10% to 30% by weight, based on the total weight of monomers present in the ethylene acid copolymer.

[0064] Examples of α,β-ethylenically unsaturated C3-C8 carboxylic acids (component (b)) include acrylic acid, methacrylic acid, itaconic acid, crotonic acid (trans-butenic acid), isocrotonic acid (cis-butenic acid), vinyl acetic acid, (E)-4-methoxy-4-oxobuta-2-enoic acid, (Z)-4-ethoxy-4-oxobuta-2-enoic acid, vinyl lactic acid, maleic acid, 2-methylmaleic acid, or aconitic acid, or mixtures thereof. In one embodiment, the C3-C8 α,β-ethylenically unsaturated carboxylic acid is acrylic acid, methacrylic acid, or a combination of acrylic acid and methacrylic acid.

[0065] The ethylene acid copolymer may optionally contain a C3-C8 α,β ethylenically unsaturated carboxylic acid ester (component (c)). If a C3-C8 α,β ethylenically unsaturated carboxylic acid ester (component (c)) is present, component (c) may include a monoester, or in some examples, a diester of an α,β-unsaturated dicarboxylic acid with a primary, secondary, and / or tertiary saturated monohydric alcohol having 1 to 20 carbon atoms. The acid ester may be, for example, a methyl ester, ethyl ester, propyl ester, butyl ester, or 2-ethylhexyl ester of acrylic acid, methacrylic acid, and / or itaconic acid, or a corresponding monoester or diester of maleic acid, fumaric acid, or citraconic acid.

[0066] In one embodiment, the ethylene acid dispersion may include a neutralizing agent. As used herein, “neutralizing agent” is a base that reacts with an acidic functional group in an EAC in an acid-base reaction to form a salt. The neutralizing agent is used to control the pH, if present, and provides stability to the formulated pressure-sensitive adhesive composition. The neutralizing agent is present in an amount greater than 0% to 2% by weight, or 0.1% to 1.5% by weight, based on the total dry weight of the aqueous pressure-sensitive adhesive composition.

[0067] In one embodiment, the neutralization of EAC is 25% to 200% on a molar basis; or 50% to 150% on a molar basis; or 50% to 120% on a molar basis; or 50% to 110% on a molar basis. Non-limiting examples of suitable neutralizing agents include hydroxides, carbonates, bicarbonates, amines, and combinations thereof.

[0068] Non-limiting examples of suitable hydroxides include ammonium hydroxide, potassium hydroxide, lithium hydroxide, and sodium hydroxide.

[0069] Non-limiting examples of suitable carbonates include sodium carbonate, sodium bicarbonate, potassium carbonate, and calcium carbonate.

[0070] Non-limiting 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-methanolamine, N-aminoethylethanolamine, N-methyldiethanolamine, monoisopropanolamine, N,N-dimethylpropanolamine, 2-amino-2-methyl-1-propanol, tris(hydroxymethyl)-aminomethane, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, 1,2-diaminopropane, 2-amino-2-hydroxymethyl-1,3-propanediol, N,N'-ethylenebis[bis(2-hydroxypropyl)amine]toluene-p-sulfonate, or cyclic amines such as morpholine, piperazine, and piperidine, and combinations thereof.

[0071] In one embodiment, the aqueous pressure-sensitive adhesive composition contains 0.1 to 25% by weight, or 0.1 to 10% by weight, 0.2 to 6% by weight, or 0.3 to 4% by weight of an ethylene ester dispersion, based on the total weight of the aqueous pressure-sensitive adhesive composition.

[0072] In one embodiment, the water-based pressure-sensitive adhesive composition contains 0.1 to 25% by weight, or 0.1 to 10% by weight, or 0.2 to 6% by weight, or 0.3 to 4% by weight of EEP, based on the total dry weight of the adhesive composition.

[0073] C. Tackifiers In one embodiment, the water-based pressure-sensitive adhesive composition includes a tackifier. Suitable tackifiers include, but are not limited to, rosin resins containing rosin acid and / or rosin esters obtained by esterifying rosin acid with alcohol, epoxy compounds and / or mixtures thereof, non-hydrogenated aliphatic C5 resins, hydrogenated aliphatic C5 resins, aromatically modified C5 resins, terpene resins, hydrogenated C9 resins, (meth)acrylic resins, and combinations thereof. Suitable (meth)acrylic resins as tackifiers are described in reference to U.S. Patent No. 4,912,169, U.S. Patent Application Publication No. 2002 / 055587, and U.S. Patent No. 9,605,188. The water-based pressure-sensitive adhesive composition contains more than 0% to 50% by weight, or 5% to 40% by weight, or 7% to 30% by weight, or 8% to 15% by weight of the tackifier, based on the total dry weight of the water-based pressure-sensitive adhesive composition.

[0074] D. Additives The water-based pressure-sensitive adhesive composition may further contain one or more optional additives. If additives are present, non-limiting examples of suitable additives include thickeners, defoamers, wetting agents, mechanical stabilizers, pigments, fillers, freeze-thaw agents, plasticizers, adhesion promoters, and combinations thereof.

[0075] In one embodiment, the water-based pressure-sensitive adhesive composition contains more than 0% to 5% by weight of a 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 available on the market from The Dow Chemical Company in Midland, Michigan.

[0076] E.PSA composition Aqueous PSA composition, (A) Acrylic dispersions in a concentration of 40% to 99.9% by weight, or 93% to 99.8% by weight, or 95% to 99.7% by weight; (B) Ethylene polymer dispersion in a concentration of 10% to 0.1% by weight, or 7% to 0.2% by weight, or 5% to 0.3% by weight; (C) Based on the total dry weight of the water-based pressure-sensitive adhesive composition, it contains 0% by weight, or greater than 0% by weight to 50% by weight, or 5% to 40% by weight, or 7% to 30% by weight, or 8% to 15% by weight of a tackifier. It is understood that the total dry weight of components (A), (B), and (C) reaches 100% by dry weight.

[0077] F. Goods This disclosure provides articles comprising a first substrate and a layer of an aqueous PSA composition on the first substrate (hereinafter referred to as the PSA layer). The aqueous PSA composition is any aqueous PSA composition already disclosed herein and comprises (A) an acrylic dispersion comprising (i) an acrylic polymer having a glass transition temperature (Tg) of less than -20°C and (ii) a surfactant; (B) an ethylene ester dispersion comprising (i) particles of an ethylene / ester polymer (EEP) and (ii) a dispersant; and (C) any tackifier. The ethylene / ester polymer contains 1% to less than 50% by weight of an acrylate comonomer.

[0078] In one embodiment, the article is a pressure-sensitive adhesive article. As used herein, “pressure-sensitive adhesive article” is an article to which a pressure-sensitive adhesive (PSA) is bonded to a first substrate, having an exposed surface which is an available surface that can be brought into contact with a second substrate. The “available surface” consists of any of the aqueous PSA compositions already disclosed herein. The available surface of the PSA may or may not be in contact with a release material. As used herein, the “release material” is a material that forms a weak bond with the PSA and can be easily removed by hand to expose the available surface.

[0079] The article includes a first substrate. The first substrate is a film, a cellulose-based material, a fabric, a tape or release liner, or a combination thereof.

[0080] In one embodiment, the first substrate is a film. Non-limiting examples of films suitable for the first substrate include plastic films (unstretched films, uniaxially oriented films, or biaxially oriented films) such as propylene polymer films, ethylene polymer films, ethylene / propylene copolymer films, polyester films, poly(vinyl chloride) films, and metal vapor-deposited films; foam substrates such as polyurethane foam and polyethylene foam; and metal foils such as aluminum foil or copper foil.

[0081] In one embodiment, the first substrate is a cellulose-based material. Non-limiting examples of cellulose-based materials suitable for the substrate include paper such as kraft paper, crepe paper, and Japanese paper, as well as labels and cardboard.

[0082] In one embodiment, the first base material is a fabric. Non-limiting examples of fabrics suitable for the base material include cotton fabrics, staple fiber fabrics, nonwoven fabrics such as polyester nonwovens, vinyl on nonwoven fabrics, and combinations thereof.

[0083] In one embodiment, the first substrate is a release liner. Non-limiting examples of materials suitable for the release liner include fluorocarbon polymers (e.g., polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chlorofluoroethylene-vinylidene fluoride copolymer, etc.), silicone-coated paper or film, and non-polar polymers (e.g., olefin resins such as ethylene-based polymers and propylene-based polymers).

[0084] In one embodiment, the thickness of the first substrate (film, cellulose-based material, fabric, tape, or release liner) is 10 microns to 10,000 microns, or 10 microns to 1,000 microns, or 20 microns to 500 microns, or 50 microns to 100 microns, or 100 microns to 200 microns, or 200 microns to 500 microns.

[0085] The PSA layer is formed by applying an aqueous PSA composition to one or both sides of a first substrate and then drying or curing it. The aqueous PSA composition may be any aqueous PSA composition already disclosed herein. For applying the PSA composition, coaters such as gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roller coaters, bar coaters, knife coaters, spray coaters, curtain coaters, slot die coaters, comma coaters, and knife coaters can be used. In one embodiment, one or both sides of the substrate to which the pressure-sensitive adhesive layer is applied are surface-treated. Non-limiting examples of suitable surface treatments include primer coating and corona discharge surface treatment on one or both sides of the substrate before application of the PSA layer.

[0086] In one embodiment, the thickness of the PSA layer on the substrate surface is 1 micron to 500 microns, or 10 microns to 110 microns, or 30 microns to 90 microns, or 1 micron to 10 microns, or 10 microns to 50 microns.

[0087] In one embodiment, the article is a multilayer PSA article. As used herein, “multilayer PSA article” includes a substrate and two or more PSA layers, each having a first PSA layer in contact with the substrate and a second PSA layer in contact with the first PSA layer. The multilayer PSA article may include further PSA layers, each of which is in contact with a previously applied PSA layer, and the PSA layers are arranged in a laminated manner. For example, the multilayer PSA article includes a third PSA layer, the third PSA layer is in contact with a second PSA layer, and the third PSA layer can be laminated thereon. The multilayer PSA article includes a fourth PSA layer, the fourth PSA layer is in contact with a third PSA layer, and the fourth PSA layer can be laminated thereon. The multilayer PSA article includes a fifth PSA layer, the fifth PSA layer is in contact with a fourth PSA layer, and the fifth PSA layer can be laminated thereon. At least one PSA layer of the multilayer PSA article is composed of any of the aqueous PSA compositions already disclosed herein.

[0088] Rather than being limiting, some embodiments of the present disclosure are described in detail below in the following examples. [Examples]

[0089] The materials used in the examples are provided in Tables 1A and 1B below.

[0090] [Table 1]

[0091] [Table 2]

[0092] EER1, EER2, and EER3 The experimental copolymers EER1, EER2, and EER3 can be prepared by a standard free radical copolymerization method using high pressure and operating in a continuous manner. Monomers are supplied to the reaction mixture in proportions related to the reactivity of the monomers and the amount to be incorporated. In this way, a uniform and nearly 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. Patent No. 4,351,931.

[0093] A. Melt Index (MI) - Melt Viscosity (Mv) Relationship The following calculation, cited from Shenoy, AV; Saini, DR; Nadkarni, VMPolymer 1983, 24, 722-728, allows us to estimate the melt index at 190°C from the melt viscosity at 140°C. (See below)

[0094]

number

[0095]

number

[0096]

number

[0097] As an example, for EAA Honeywell AC 5120 polymer, its melt viscosity at 140°C is 6 poise and its density is 0.93 g / cm³. 3 ), the MI at 190°C can be estimated from the calculated glass transition temperature for a copolymer of 85% ethylene and 15% acrylic acid.

[0098] [Table 3] * Estimated monomer composition, weight % based on the total weight of the material E-ethylene, VA-vinyl acetate, AA-acrylic acid.

[0099] 1. Preparation of acrylic dispersion A. Acrylic dispersion 1 Acrylic dispersion 1 is prepared according to the following procedure: 540 g of deionized ("DI") water is supplied to a 4-liter five-port reactor equipped with a condenser, a mechanical stirrer, a temperature-controlled thermocouple, and inlets for the initiator and monomer, and heated to 87°C under a gentle nitrogen flow. In a separate vessel, 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 monomer mixture consisting of 71.5 wt% 2-ethylhexyl acrylate ("2-EHA"), 18.5 wt% ethyl acrylate ("EA"), 9 wt% methyl methacrylate ("MMA"), and 1 wt% acrylic acid ("AA"). Next, a mixture of 1.3 g of sodium carbonate and 8.3 g of ammonium persulfate ("APS" as an initiator) in 32 g of DI water is added to the reactor. Immediately after adding the sodium carbonate and APS solution, the monomer emulsion is supplied to the reactor. The supply is continued for 80 minutes. Upon completion of the monomer emulsion addition, the reaction mixture is cooled to 60°C, and then, over 25 minutes, a solution of tert-butyl hydroperoxide (70%) ("t-BHP") (4.7 g in 23 g of DI water) and sodium hydroxymethanesulfonate (2.8 g in 28 g of DI water) is gradually added through two separate feed pipes. After the supply is complete, the reaction mixture is cooled to room temperature. Next, the resulting acrylic dispersion 1 is filtered through a 325 mesh filter cloth to prepare a composition for subsequent evaluation. The resulting acrylic dispersion 1 contains an acrylic polymer composed of 71.5% by weight of 2-EHA, 18.5% by weight of EA, 9% by weight of MMA, and 1% by weight of AA, and has a glass transition temperature of -41°C. The weight percentages are based on the total dry weight of the acrylic polymer.

[0100] B. Acrylic dispersion 2 Acrylic dispersion 2 is INVISU® 4100, available from Dow Chemical Company.

[0101] C. Acrylic dispersion 3 Acrylic dispersion 3 is INVISU® 3000, available from Dow Chemical Company.

[0102] D. Acrylic dispersion 4 In a flask containing 270 g of water (90°C) prepared for semi-continuous emulsion polymerization, 13 g of a deionized aqueous solution of sodium peroxodisulfate (1.26 g) was added first, followed by 21.2 g of crystalline species consisting of an aqueous dispersion of acrylic polymer with 12% solids and an average particle size of 60 nm. After 2 minutes, a feed stream containing 59.8 g of a deionized aqueous solution of sodium peroxodisulfate (3.79 g) and a monomer emulsion was added and continued at a constant rate at 90°C for 120 minutes. The monomer emulsion consisted of 1250 g of monomers in the weight ratios listed in Table 2, consisting of 180 g of a 33% aqueous solution of sodium lauryl alcohol sulfate ethoxylated with 30 mol of ethylene oxide, 5.6 g of a 44% aqueous solution of DOWFAX® 2A1, 6.7 g of an ethanol / aqueous solution of sodium dioctyl sulfosuccinate at 75% concentration, and 295 g of deionized water. After adding half the weight of the monomer emulsion to the reactor, 72 g of crystalline species consisting of an aqueous dispersion of acrylic polymer with 26% solids and an average particle size of 60 nm was added to the reactor within 1 minute. After the monomer emulsion and feed stream were completely added to the reactor, a further 35 g of deionized water was added while maintaining the reactor temperature at 90°C. Next, 17.9 g of ammonia (at a concentration of 4.4% in water) was added to the reactor. Finally, 23 g of an 8% aqueous solution of tert-butyl hydroperoxide and 19.5 g of an aqueous solution of sodium hydroxymethanesulfinate were added to the reactor at a constant rate over 60 minutes at 90°C. After these feed streams were completed, the reactor contents were cooled to room temperature.

[0103] E. Acrylic dispersion 5 Using a flask equipped with a mechanical stirrer, the initial aqueous input consisting of 0.51 g of tetrasodium pyrophosphate, 640 g of deionized water, 1.80 g of anhydrous sodium sulfate, and 1.36 g of ascorbic acid is heated to 87°C. Next, 28.4 g of 19% aqueous sodium persulfate solution is poured into the flask. Over 2.0 hours, an emulsion consisting of 14.7 g of 50% aqueous sodium hydroxide solution, 39.4 g of 30% aqueous solution of sodium sulfate of lauryl alcohol ethoxylated with 12 moles of ethylene oxide, 21.2 g of 25.0% aqueous sodium vinyl sulfonate solution, 28.8 g of 22% aqueous sodium dodecylbenzenesulfonate solution, 6.6 g of itaconic acid, 236 g of water, 321.2 g of methyl methacrylate, 55.2 g of styrene, 1,592.4 g of 2-ethylhexyl acrylate, 679.3 g of ethyl acrylate, and 14.4 g of acrylic acid is gradually supplied to the flask. Initially, the supply rate for the first 5.0 minutes is 5.0 g per minute. Then, this rate is steadily increased to 25.0 g per minute over 35 minutes. After a total supply time of 75 minutes, the rate is increased to 35.0 g per minute. From the start of emulsion supply, 94 g of 11% sodium peroxodisulfate aqueous solution is added at a constant rate over 2.3 hours, while maintaining the reactor temperature at 85-87°C.

[0104] After the supply is complete, a solution of 2.76 g of sodium bisulfite, 1.8 g of acetone, and 44.4 g of water, along with 47.6 g of a 5.5% tert-butyl hydroperoxide solution, is dispensed into the flask at approximately 70°C over a period of 45 minutes. The copolymer dispersion of the pressure-sensitive adhesive is produced with a solid content of 70% by weight.

[0105] F. Acrylic dispersion 6 Using a flask equipped with a mechanical stirrer, heat the input consisting of 1.34 g of tetrasodium pyrophosphate, 269 g of deionized water, and 0.68 g of ascorbic acid to 86°C. Next, pour 28 g of 6.6% sodium persulfate in water into the flask. Over a period of 4 hours, an emulsion consisting of 24.5 g of 10% sodium hydroxide solution, 30 g of a 33% aqueous solution of sodium sulfate of lauryl alcohol ethoxylated with 30 moles of ethylene oxide, 10.6 g of a 25.0% aqueous solution of sodium vinyl sulfonate, 5 g of a 44% aqueous solution of DOWFAX® 2A1, 2.2 g of lauryl alcohol ethoxylated with 7 moles 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 a flask. At the start, the addition rate for the first 6 minutes is 1.42 g / min. Thereafter, the addition rate is increased to a constant 7.1 g / min over a period of 40 minutes. From the start of emulsion supply, 148 g of a 5% sodium peroxodisulfate solution in water is added at a constant rate over 5 hours, while maintaining the reaction medium at 85-87°C.

[0106] After the supply has finished, at approximately 70°C, a solution of 1.38 g of sodium bisulfite, 0.9 g of acetone, and 22.2 g of water, along with 23.8 g of a 5.5% solution of tert-butyl hydroperoxide, are dispensed into the flask over a period of 60 minutes.

[0107] G. Acrylic dispersion 7 Sodium carbonate (0.01% BOM, 0.55 g) was added as a buffer to a kettle (518 g) of 96°C water swept with nitrogen and equipped with an overhead stirrer, thermometer, and reflux condenser. Subsequently, ammonium persulfate (0.217% BOM, 5.9 g) and a matrix crystal species input set to the initial particle size (100 nm starting particle size, 1.251% BOM, 70.79%) were added as initiators. Monomer emulsion feeding and co-feeding were initiated. The monomer emulsion consisted of sodium carbonate (0.02% BOM, 1.4g), itaconic acid (0.2g, 5.1g), acrylic acid (0.8% BOM, 20.4g), disodium ethoxylated alcohol hemiester of sulfosuccinic acid (0.17%, 14.3%), sodium dodecylbenzenesulfonate (0.21% BOM, 24.2g), butyl acrylate (71.1% BOM, 1818g), methyl methacrylate (6.0% BOM, 152.8g), styrene (1.6% BOM, 40.8g), and water (16.8% total monomer emulsion, 4.11g), which was supplied over 75 minutes. Ammonium persulfate (0.173% BOM, 4.6%) was supplied as a co-supply over 75 minutes. The reaction temperature was controlled at 88-90°C. The monomer emulsion supply was interrupted, and sodium dodecylbenzenesulfonate (0.235% BOM, 26.5 g) was added to the kettle. After adding the monomer emulsion, the temperature was maintained. After 15 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) were added to the kettle. Subsequently, the supply and co-supply of the monomer emulsion were started. The monomer emulsion consisted of tetrasodium 1,1-diphosphonatoethanol (0.002%, 0.1%), acetate (0.03% BOM, 0.6g), sodium dodecylbenzenesulfonate (0.05% BOM, 5.3g), butyl acrylate (5% BOM, 127.8g), butyl methacrylate (15% BOM, 353.3g), methyl 3-mercaptopropionate (0.38% BOM, 9.8g), and water (105.7g), which was supplied over a period of 20 minutes.One co-supply consisted of t-butyl hydroperoxide (0.4% BOM, 15.1 g) and was supplied for 50 minutes. The other co-supply consisted of sodium hydroxymethanesulfonate (0.24% BOM, 8.1 g) and was supplied for 50 minutes. The temperature was controlled to 74-76°C while supplying the monomer emulsion. After the monomer emulsion was complete, the batch was cooled to 65°C. Next, the dispersion was neutralized with ammonium hydroxide until the pH reached 7. After neutralization, the batch was cooled to below 35°C.

[0108] Table 2 below provides an overview of the properties of acrylic dispersions 1 to 7, with the amounts of each component expressed as weight percentages based on the dry weight of the acrylic dispersion.

[0109] [Table 4] Weight percentage based on the dry weight of the acrylic dispersion.

[0110] 2. Preparation of ethylene ester dispersion Aqueous ethylene ester dispersions EEP1-8 were prepared using a Bersdorf ZE25 48 L / D 25 mm twin-screw extruder (Kraus-Maffei Corporation, Florence KY, USA) rotating at 450 rpm, following the procedure below. The ethylene ester polymer (EEP feed 1 in Table 3 below) was supplied to the extruder's feed port via a Schenck Mechatron gravimetric continuous quantitative feeder, and additional resin (resin feed 2) was added via a K-tron gravimetric continuous quantitative feeder to control the blend composition. The EEP resin and any additive were melt-blended, then emulsified in the presence of the initial aqueous solution stream (IA) and dispersant, neutralized with potassium hydroxide (KOH) or dimethylethanolamine where applicable, and both were injected using an ISCO dual syringe pump (Teledyne Isco, Inc., Lincoln NE, USA). Next, the dispersed phase was transported to the dilution and cooling zones of the extruder, where further dilution water was added using an ISCO dual syringe pump to form an aqueous dispersion with a solid content of less than 70% by weight. The extruder barrel temperature was set to 140-150°C. After the ethylene ester dispersion exited the extruder, it was further cooled and filtered through a 200 μm mesh bag filter.

[0111] The specific supply speed and results are shown in Table 3 below.

[0112] [Table 5]

[0113] Aqueous ethylene ester dispersions EEP9-11 were prepared using a 2CV Helicone mixer (DIT), a jacketed batch mixer employing twin-screw meshing conical blades for mixing high-viscosity materials (up to 12 mm cP). This unit incorporates a bottom discharge valve, allowing the mixer blades to be used to push the material through the valve after mixing. The working volume of the 2CV unit is 50-250 mL. A large-capacity recirculation bath was connected to the mixing bowl jacket to heat the unit, and dilution water was injected into the system using ISCO during mixing. Additionally, the Helicone utilized a secondary oil pump to maintain constant pressure to the mechanical seal of the blade shaft, offsetting the pressure within the vessel.

[0114] As shown in Table 4, dispersions were prepared. The resin, surfactant, base, and initial aqueous solution (IA) were packed into a helicone, then pressurized to 70 psi under a nitrogen atmosphere generator, and the heater was set to 140°C. After 30 minutes, the components reached the desired temperature, and the mixture was mixed at 50 rpm for 30 minutes to produce an initial emulsion. Next, the impeller speed was increased to 100 rpm, and deionized water was added at a rate of 1.5 mL / min to dilute the emulsion to 60% solid, and then diluted at a rate of 2.5 mL / min to the final target concentration of approximately 40% solid. After dilution, mixing was stopped, and the dispersion was cooled for 30 minutes until the temperature fell below 80°C. At this point, the helicone was evacuated, and the dispersion was recovered through a gate valve.

[0115] [Table 6]

[0116] 3. Preparation of pressure-sensitive adhesive composition The water-based pressure-sensitive adhesive compositions were formulated as follows. Unless otherwise specified, all samples were formulated with a 0.3% (wet / wet) SURFYNOL 440 wetting agent obtained from Evonik ("440") based on the total dispersion to improve wet-out during laboratory drawdown. Next, the viscosity was adjusted to approximately 600 mPa·s (600 cps) (Brookfield, RVDV, 30 rpm, 63#) using ACRYSOL® DR-5500 ("DR-5500"), a thickening agent available from Dow, Inc., Midland, Michigan, and the final pH was adjusted to 7.0–7.5 using ammonium hydroxide.

[0117] The acrylic dispersion was mixed with an ethylene ester dispersion in accordance with the dose levels shown in each table (wet weight or dry weight based on the total weight of the acrylic dispersion), after proper stirring.

[0118] 4. Preparation of PSA articles Laboratory drawdown A polypropylene ("PP") film (60 microns thick) was pre-treated with corona treatment before lamination. A sample of an aqueous PSA composition was coated onto release paper and dried at 80°C for 5 minutes. The PP film was laminated with a release liner coated with an aqueous pressure-sensitive adhesive ("adhesive lamination").

[0119] The adhesive laminates were conditioned in a controlled environment (22.2–23.3°C (72–74°F), 50% relative humidity) for at least one day (24 hours) before performance testing was conducted.

[0120] Before use in adhesive testing, clean and condition the high-density polyethylene (HDPE) panels purchased from Cheminstruments (510 Commercial Dr., West Chester Township, OH 45014). Wipe the panels with a lint-free, non-abrasive cloth soaked in isopropanol to remove any adhesive residue before testing. Take care not to scratch the surface. Once the panel surface is visually clean, wipe it again with isopropanol. Condition the HDPE panels at 22.2–23.3°C (72–74°F) and 50% relative humidity for a minimum of 4 hours and no more than 24 hours.

[0121] 5. PSA application test to evaluate EEP1 The water-based PSA composition in the adhesive laminate was completely dried and then conditioned at a controlled environment (22.2–23.3°C, 50% relative humidity) in a testing laboratory for at least one night, and in some cases 120 hours at a weight of 12 kg, before performance testing was performed.

[0122] Tables 5 to 7 below provide peel tack, loop tack, and shear data for adhesive laminates containing a dry PSA composition comprising (i) an acrylic dispersion 2 and (ii) an ethylene ester dispersion.

[0123] [Table 7] CS = Comparative Sample, IE = Example of the Invention

[0124] The 90° peel adhesion (24 hours and 20 minutes) of HDPE obtained from PSA articles (laminates) prepared from the acrylic dispersion 2 formulation increased more than expected with the addition of EEP copolymer dispersion. CS1 without EEP copolymer showed a 90° peel adhesion (24 hours) of HDPE of 4.0 N / inch, compared to IE2 which showed a 90° peel adhesion (24 hours) of HDPE of 5.1 N / inch with 2 parts of EEP1. Furthermore, unexpectedly, the 90° peel adhesion (24 hours) of HDPE actually increased further to 5.3 N / inch with the addition of less EEP1 (only 0.4 parts). Even more unexpectedly, the 90° peel adhesion (24 hours) of HDPE increased with the addition of 2 parts of EEP1 (20 minutes), but not with the addition of only 0.4 parts of EEP1.

[0125] 6. PSA application test to evaluate EEP2, EEP3, EEP4, EEP5, and EEP6. Acrylic dispersion 2 was added to EEP, and a PSA application test was conducted according to the method described above.

[0126] [Table 8]

[0127] The 90° peel adhesion (24 hours and 20 minutes) of HDPE obtained from PSA articles (laminates) prepared from the acrylic dispersion 2 formulation increased more than expected with the addition of EEP copolymer dispersion. CS2 without EEP copolymer dispersion, containing 0.4 to 4 parts EEP, exhibited a 90° peel adhesion (20 minutes) of 3.9 N / 2.54 cm for HDPE, compared to the examples of the present invention in this experiment which showed a 90° peel adhesion (20 minutes) of 4.1 to 5.6 N / 2.54 cm for HDPE. Similar observations were also made for the 90° peel adhesion (24 hours) of HDPE, and all examples of the present invention containing EEP showed even higher adhesion compared to CS2.

[0128] 7. PSA application test to evaluate EEP9 Acrylic dispersion 2 was added to EEP, and a PSA application test was conducted according to the method described above.

[0129] [Table 9]

[0130] The 90° peel adhesion and loop tack of HDPE obtained from PSA articles (laminates) prepared from the acrylic dispersion 2 formulation increased more than expected with the addition of EEP9 copolymer dispersion. Compared to the examples of the present invention in this experiment, CS2 without EEP9 dispersion, which contains 0.4 to 4 parts of EEP9, shows a 90° peel adhesion of HDPE of 5.3 to 5.5 N / 2.54 cm (24 hours) and a loop tack of 6.2 to 6.6 N, CS2 shows a 90° peel adhesion of HDPE of 5.1 N / 2.54 cm (24 hours) and a loop tack of 5.0 N.

[0131] 8. Performance testing of formulations of EEP5 and EEP9 with other acrylic dispersions. The acrylic dispersion was mixed with an EMAA-based dispersion according to the dosage levels shown in each table (wet weight based on the total weight of the acrylic dispersion), after being properly stirred until mixed.

[0132] [Table 10]

[0133] 9. PSA application test to evaluate EEP7 and EEP8 Acrylic dispersion 2 was added to EEP, and a PSA application test was conducted according to the method described above.

[0134] [Table 11]

[0135] The 90° peel adhesion (20 min and 24 hPa) of HDPE obtained from PSA articles (laminates) prepared from the acrylic dispersion 2 formulation increased more than expected with the addition of EEP copolymer dispersion. CS2 without EEP copolymer dispersion, containing 0.4 parts EEP, exhibited a 90° peel adhesion (20 min) of 3.8 N / 2.54 cm for HDPE, compared to the embodiment of the present invention in this experiment, which showed a 90° peel adhesion (20 min) of 4.4-4.0 N / 2.54 cm for HDPE. Similar observations were also made for the 90° peel adhesion of HDPE at IE25 over 24 hours, indicating that all embodiments of the present invention containing EEP exhibited even higher adhesion compared to CS2.

[0136] 10. PSA application test to evaluate EEP10 and EEP11 Acrylic dispersion 2 was added to EEP, and a PSA application test was conducted according to the method described above.

[0137] [Table 12]

[0138] The 90° peel adhesion (20 minutes and 24 hours) of HDPE obtained for PSA articles (laminates) prepared from the acrylic dispersion 2 formulation increased more than expected with the addition of EEP copolymer dispersion. Compared to the examples of the present invention in this experiment, CS2 without EEP copolymer dispersion, which contains 0.4 to 2 parts EEP, shows a 90° peel adhesion (24 hours) of HDPE of 3.2 to 3.5 N / 2.54 cm, while CS2 shows a 90° peel adhesion (24 hours) of HDPE of 2.9 N / 2.54 cm. Therefore, after a residence time of 24 hours, EEP copolymer dispersion increases the adhesion of articles containing such dispersions more than expected.

[0139] This disclosure is not limited to the embodiments and examples contained herein, but is particularly intended to include some embodiments and modified forms of those embodiments, including combinations of elements of different embodiments, to the extent that they fall within the scope of the following claims. Furthermore, although this application relates to the invention described in the claims, it may also encompass the following as other embodiments. (1) A water-based pressure-sensitive adhesive composition, (A) Acrylic dispersion, (i) Acrylic polymers having a glass transition temperature (Tg) of less than -20°C, (ii) A surfactant and an acrylic dispersion containing particles of the surfactant, (B) Ethylene ester dispersion, (i) Particles of an ethylene ester polymer having an acrylate comonomer content of 1% to less than 50% by weight, (ii) A water-based pressure-sensitive adhesive composition comprising a dispersant and an ethylene ester dispersion containing a dispersant. (2) The acrylic polymer is 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 12 ~C 18 The aqueous pressure-sensitive adhesive composition according to (1) above, comprising one or more acrylic monomers selected from the group consisting of alkyl methacrylate, cyclohexyl methacrylate, methacrylic acid, and combinations thereof. (3) The water-based pressure-sensitive adhesive composition according to (1) or (2) above, wherein the acrylic polymer comprises a monomer selected from the group consisting of styrene, vinyl esters, and combinations thereof. (4) The water-based pressure-sensitive adhesive composition according to any one of (1) to (3) above, wherein the Tg of the acrylic polymer is -80°C to -20°C. (5) The aqueous pressure-sensitive adhesive composition according to any one of (1) to (4) above, wherein the volume average particle size of the ethylene ester polymer particles is 0.1 microns to 2.0 microns. (6) The aqueous pressure-sensitive adhesive composition according to any one of (1) to (5) above, wherein the ethylene ester polymer comprises ethylene units and comonomers selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl methacrylate and combinations thereof. (7) The aqueous pressure-sensitive adhesive composition according to any one of the above items (1) to (6), wherein the melt index of the ethylene ester polymer is 1 g / 10 min to 60 g / 10 min. (8) The ethylene ester polymer The density is 0.920 g / cc to 0.960 g / cc. The melting point Tm is 70°C to 110°C. A water-based pressure-sensitive adhesive composition according to any one of the above items (1) to (7), wherein the Vicat softening point is 40°C to 80°C. (9) The aqueous pressure-sensitive adhesive composition according to any one of (1) to (8) above, wherein the dispersant is selected from the group consisting of long-chain fatty acids having 14 to 40 carbon atoms, anionic surfactants, cationic surfactants, nonionic surfactants, polyethylene having acidic functional groups, polypropylene having acidic functional groups, and combinations thereof. (10) The aqueous pressure-sensitive adhesive composition according to any one of (1) to (9) above, wherein the ethylene ester dispersion contains a neutralizing agent. (11) A water-based pressure-sensitive adhesive composition according to any one of the above items (1) to (10), (A) The acrylic dispersion liquid in an amount of 40% to 99.8% by weight; (B) 10% to 0.2% by weight of the ethylene polymer dispersion; (C) Contains 0% to 50% by weight of a tackifier; A water-based pressure-sensitive adhesive composition, wherein the weight percentage is based on the total dry weight of the water-based pressure-sensitive adhesive composition. (12) Articles, The first substrate and The first substrate comprises a layer of water-based pressure-sensitive adhesive composition, wherein the water-based pressure-sensitive adhesive composition is (A) Acrylic dispersion, (i) Acrylic polymers having a glass transition temperature (Tg) of less than -20°C, (ii) A surfactant and an acrylic dispersion containing particles of the surfactant, (B) Ethylene ester dispersion, (i) Particles of an ethylene ester polymer having an acrylate comonomer content of 1% to less than 50% by weight, (ii) An article comprising a dispersant and an ethylene ester dispersion containing a dispersant.

Claims

1. A water-based pressure-sensitive adhesive composition, (A) An acrylic dispersion liquid in an amount of 93% to 99.8% by weight, based on the total dry weight of the aqueous pressure-sensitive adhesive composition, (i) Acrylic polymers having a glass transition temperature (Tg) of less than -20°C, (ii) A surfactant and an acrylic dispersion containing particles An acrylic dispersion containing, (B) comprising 0.2% to 7% by weight of an ethylene ester dispersion based on the total dry weight of the aqueous pressure-sensitive adhesive composition, wherein the aqueous pressure-sensitive adhesive composition is a mixture of the (A) acrylic dispersion and the (B) ethylene ester dispersion, The (B) ethylene ester dispersion is (i) Particles of ethylene ester polymer, (1) Units derived from ethylene, (2) An acrylate comonomer in an amount of 1% to less than 50% by weight, selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, glycidyl methacrylate and combinations thereof, (3) If necessary, containing one or more ter monomers selected from the group consisting of vinyl acetate and acrylic acid, Particles of ethylene ester polymer, (ii) A dispersant and an ethylene ester dispersion containing, The ethylene ester polymer The density is 0.920 g / cc to 0.960 g / cc. The melting point Tm is 70°C to 110°C. A water-based pressure-sensitive adhesive composition having a Vicat softening point of 40°C to 80°C.

2. The aforementioned acrylic polymers 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, and C. １２ ~C １８ The aqueous pressure-sensitive adhesive composition according to claim 1, comprising one or more acrylic monomers selected from the group consisting of alkyl methacrylate, cyclohexyl methacrylate, methacrylic acid, and combinations thereof.

3. The aqueous pressure-sensitive adhesive composition according to claim 1 or 2, wherein the acrylic polymer comprises a monomer selected from the group consisting of styrene, vinyl esters, and combinations thereof.

4. The aqueous pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the Tg of the acrylic polymer is -80°C to -20°C.

5. The aqueous pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the volume-average particle size of the ethylene ester polymer particles is 0.1 microns to 2.0 microns.

6. The aqueous pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the ethylene ester polymer comprises ethylene units and a comonomer selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl methacrylate, and combinations thereof.

7. The aqueous pressure-sensitive adhesive composition according to any one of claims 1 to 6, wherein the melt index of the ethylene ester polymer, as measured by ASTM D1238 (190°C / 2.16 kg), is 1 g / 10 min to 60 g / 10 min.

8. The aqueous pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the dispersant is selected from the group consisting of long-chain fatty acids having 14 to 40 carbon atoms, anionic surfactants, cationic surfactants, nonionic surfactants, polyethylene having acidic functional groups, polypropylene having acidic functional groups, and combinations thereof.

9. The aqueous pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the ethylene ester dispersion contains a neutralizing agent.

10. A water-based pressure-sensitive adhesive composition according to any one of claims 1 to 9, (A) The acrylic dispersion in an amount of 95% to 99.7% by weight; (B) 0.3% to 5% by weight of the ethylene ester dispersion; (C) comprising 0% to 50% by weight of a tackifier; A water-based pressure-sensitive adhesive composition, wherein the weight percentage is based on the total dry weight of the water-based pressure-sensitive adhesive composition.

11. Articles, The first substrate and The first substrate comprises a layer of water-based pressure-sensitive adhesive composition, wherein the water-based pressure-sensitive adhesive composition is (A) An acrylic dispersion liquid in an amount of 93% to 99.8% by weight, based on the total dry weight of the aqueous pressure-sensitive adhesive composition, (i) Acrylic polymers having a glass transition temperature (Tg) of less than -20°C, (ii) A surfactant and an acrylic dispersion containing particles (B) comprising 0.2% to 7% by weight of an ethylene ester dispersion based on the total dry weight of the aqueous pressure-sensitive adhesive composition, wherein the aqueous pressure-sensitive adhesive composition is a mixture of the (A) acrylic dispersion and the (B) ethylene ester dispersion, The (B) ethylene ester dispersion is (1) Units derived from ethylene, (2) An acrylate comonomer in an amount of 1% to less than 50% by weight, selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, glycidyl methacrylate and combinations thereof, (3) If necessary, containing one or more ter monomers selected from the group consisting of vinyl acetate and acrylic acid, Particles of ethylene ester polymer, (ii) A dispersant, The ethylene ester polymer The density is 0.920 g / cc to 0.960 g / cc. The melting point Tm is 70°C to 110°C. The Vicat softening point is 40°C to 80°C. Goods.

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