Aqueous polyolefin dispersions with ionomer dopants and methods of production thereof

Abstract

Embodiments of aqueous polyolefin dispersions and methods for producing same are provided wherein the aqueous polyolefin dispersions comprise a blend of ethylene acid copolymer dispersant, which comprises the polymerized reaction product of 90.2 to 93.3 mol.% ethylene and 6.7 to 9.8 mol.% carboxylic acid containing comonomer based on the total weight of monomers present in the dispersant and partially neutralized ionomer dopant, which is an ethylene acid copolymer comprising the polymerized reaction product of 94.2 to 98.3 mol.% ethylene and 1.7 to 5.8 mol.% carboxylic acid containing comonomer, based on the total weight of monomers present in the ethylene acid copolymer.

Description

AQUEOUS POLYOLEFIN DISPERSIONS WITH IONOMER DOPANTS AND METHODS OF PRODUCTION THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 579,619 filed August 30, 2023, the contents of which are incorporated in their entirety herein.FIELD

[0002] Embodiments disclosed herein generally relate to methods for making aqueous polyolefin dispersions and more specifically, to aqueous polyolefin dispersions that include an ionomer as a dopant.TECHNICAL BACKGROUND

[0003] Ethylene acrylic acid (EAA) and ethylene methacrylic acid (EMAA) copolymers are commonly used as dispersants in making dispersions of various polyolefin polymers. When used in such dispersions, EAA / EMAA copolymers often do not achieve robust, stable dispersions of polyolefin resins, especially when the EAA or MAA content is not high enough.

[0004] Accordingly, there is a continual need for improved EAA or EMAA dispersants to make processable and stable aqueous dispersions of polyolefins.SUMMARY

[0005] Embodiments of the present disclosure meet this need for improved aqueous polyolefin dispersions by melt blending a polyolefin with an ethylene acid copolymer dispersant having at least 6.5 mol.% acid content and at least a partially neutralized ionomer dopants to form a polymer melt blend. Without being limited by theory, it was surprisingly found that the inclusion of partially neutralized ionomer dopant enables better dispersion of the polymer blend resulting in more stable dispersions.

[0006] According to one or more embodiments of the present disclosure, an aqueous polyolefin dispersion that comprises polymer solid particles dispersed in water is provided,wherein the polymer solid particles comprise a polyolefin, at least an ethylene acid copolymer dispersant, and at least a partially neutralized ionomer dopant. The ethylene acid copolymer dispersant comprises the polymerized reaction product of 88.5 to 93.5 mol.% ethylene and6.5 to 11.5 mol.% carboxylic acid containing comonomer based on the total moles of monomers present in the dispersant, wherein the dispersant has a melt index (h) from 25 to 500 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg). The at least partially neutralized ionomer dopant comprises an ethylene acid copolymer, wherein the ethylene acid copolymer comprises the polymerized reaction product of 93.0 to 98.5 mol.% ethylene and 1.5 to 7.0 mol.% carboxylic acid containing comonomer, based on the total moles of monomers present in the dopant, wherein the dopant has a melt index (I2) from 0.5 to 50 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg), and wherein from 10 to 70 mol.% of total acid units of the dispersant are neutralized by metal cations. Further, the ratio by weight of dispersant to dopant is from 200: 1 to 10: 1.

[0007] According to one or more embodiments of the present disclosure, a method of producing an aqueous polyolefin dispersion is provided. The method comprises providing melt blending a polyolefin, an ethylene acid copolymer dispersant, and a partially neutralized ionomer dopant to produce a polymer melt blend. The ethylene acid copolymer dispersant comprises an ethylene acid copolymer, and the ethylene acid copolymer comprises the polymerized reaction product of 88.5 to 93.5 mol.% ethylene and 6.5 to 11.5 mol.% carboxylic acid containing comonomer based on the total moles of monomers present in the dispersant. The dispersant has a melt index (I2) from 25 to 500 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg). The method further comprises providing at least a partially neutralized ionomer dopant, which comprises an ethylene acid copolymer, wherein the ethylene acid copolymer comprises the polymerized reaction product of 93.0 to98.5 mol.% ethylene and 1.5 to 7.0 mol.% carboxylic acid containing comonomer, based on the total moles of monomers present in the dopant. The dopant has a melt index (I2) from 0.5 to 50 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg). Additionally, 10 to 70 mol.% of total acid units of the dispersant are neutralized by metal cations, and the ratio by weight of dispersant to dopant is from 200: 1 to 10: 1. In further embodiments, the ratio by weight is 150: 1 to 50: 1, or from 125: 1 to 75: 1. The method further comprises emulsifying the polymer melt blend in the presence of water and additional base to producean emulsion, wherein the additional base further neutralizes a fraction or all of the acid units of the ethylene acid copolymer dispersant, and diluting the emulsion with additional water to produce the aqueous polyolefin dispersion.

[0008] It is to be understood that both the preceding general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. Additional features and advantages of the embodiments will be set forth in the detailed description, and, in part, will be readily apparent to persons of ordinary skill in the art from that description, which includes the accompanying drawings and claims, or recognized by practicing the described embodiments. The drawings are included to provide a further understanding of the embodiments, and together with the detailed description, serve to explain the principles and operations of the claimed subject matter. However, the embodiments are illustrative and exemplary in nature, and not intended to limit the claimed subject matter.BRIEF SUMMARY OF THE FIGURE

[0009] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawing, wherein:

[0010] FIG. l is a graph illustrating the calculation of the processability factor for Inventive Examples 2 and 3 as further detailed in the Examples below.DETAILED DESCRIPTION

[0011] Specific embodiments of the present application will now be described. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0012] The term “polymer” refers to a polymeric compound prepared by polymerizing monomers, whether of a same or a different type. The generic term polymer thus embraces the term “homopolymer,” which usually refers to a polymer prepared from only one type of monomer as well as “copolymer,” which refers to a polymer prepared from two or more different monomers. The term “interpolymer,” as used herein, refers to a polymer prepared by the polymerization of at least two different types of monomers. The generic terminterpolymer thus includes a copolymer or polymer prepared from more than two different types of monomers, such as terpolymers.

[0013] “Polyethylene” or “ethylene-based polymer” shall mean polymers comprising greater than 50% by mole of units derived from ethylene monomer. This includes ethylenebased homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of ethylene-based polymers known in the art include, but are not limited to, Low Density Polyethylene (LDPE); Linear Low Density Polyethylene (LLDPE); Ultra Low Density Polyethylene (ULDPE); Very Low Density Polyethylene (VLDPE); single-site catalyzed Linear Low Density Polyethylene, including both linear and substantially linear low density resins (m- LLDPE); Medium Density Polyethylene (MDPE); and High Density Polyethylene (HDPE).

[0014] "Polypropylene" or "propylene based polymer" shall mean polymers comprising greater than 50% by mole of units derived from propylene monomer. This includes propylene-based homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of propylene-based polymers known in the art include, but are not limited to, impact polypropylene copolymers (icPP), random copolymers (rcPP), polypropylene homopolymers (hPP), propylene / ethylene copolymers (POE plastomers), and polypropylene reactor blends.

[0015] “Ethylene acid copolymer” is a polymerized reaction product of ethylene and one or more unsaturated carboxylic acids.

[0016] As used herein, “dispersion” and related terms refer to solid particles, such as, polymer particles suspended within an aqueous liquid phase. Further, as used herein, “dispersant” refers to a copolymer directed to maintaining the suspension of the polymer particles within the aqueous liquid phase.

[0017] Embodiments of the present disclosure are directed to systems and methods for producing an aqueous polyolefin dispersion by utilizing an ethylene acid copolymer dispersant and a partially neutralized ionomer dopant. The ethylene acid copolymer dispersant comprises the polymerized reaction product of 88.5 to 93.5 mol.% ethylene and 6.5 to 11.5 mol.% carboxylic acid-containing comonomer, based on the total moles ofmonomers present in the ethylene acid copolymer dispersant. The partially neutralized ionomer dopant comprises an ethylene acid copolymer, which comprise the polymerized reaction product of an 93.0 to 98.5 mol.% ethylene and 1.5 to 7.0 mol.% carboxylic acid containing comonomer, based on the total moles of monomers present in the ethylene acid copolymer, of which 10 to 70 mole % of the acid units are neutralized by metal cations. The ethylene acid copolymer dispersant, partially neutralized ionomer dopant, and one or more polyolefins are melt blended to produce a polymer melt blend and then the polymer melt blend is emulsified in the presence of water and additional base to produce an emulsion, wherein the additional base further neutralizes acid units of the partially neutralized ionomer. Then, the emulsion is diluted with additional water to produce the aqueous polyolefin dispersion.

[0018] Aqueous .Poly ;olefin Di spersion

[0019] In embodiments herein, the aqueous polyolefin dispersion may comprise a total resin solids content of from 30 to 60 wt.%, or from 40 to 50 wt.%. All individual values and subranges are included and disclosed herein. As used herein, the total resin solids content is comprised of the ethylene acid copolymer dispersant (after at least partial neutralization), ionomer dopant, polyolefin, and potentially some alkali metal cation-containing base. Various amounts are contemplated within the total resin solids content. There may be 70 wt.% to 90 wt.% polyolefin, 5 wt.% to 30 wt.% dispersant, and less than 5 wt.% dopant. In further embodiments, there may be 80 wt.% to 90 wt.% polyolefin, 10 wt.% to 20 wt.% dispersant, and from 0.01 to 1.5 wt.% dopant. In yet further embodiments, there may be 60 wt. % to 70 wt.% polyolefin, 30 wt.% to 40 wt.% dispersant, and from 0.01 to 1.5 wt.% dopant.

[0020] The particles present in the aqueous polyolefin dispersion may have a mean particle size of less than or equal to 2.00 pm, or less than 1.50 pm. All individual values and subranges are included and disclosed herein. For example, the aqueous polyolefin dispersion may have a mean particle size from 0.1 to 1.50 pm, from 0.50 to 1.50 pm, from 0.75 to 1.50 pm, from 0.80 to from 1.40 pm, or from 0.80 to from 1.30 pm. Without being limited by theory, the particles tend not to maintain colloidal stability i.e., remain suspended in the aqueous phaseat particle sizes greater than 2.0 pm, and furthermore colloidal stability tends to improve at mean particle sizes less than or equal 1.50 pm.

[0021] Various viscosities are contemplated for the aqueous polyolefin dispersion. The aqueous polyolefin dispersion may have a viscosity from 45 cP to 70 cP or from 50 cP to 65 cP. All individual values and subranges are included and disclosed herein. For example, the aqueous polyolefin dispersion may have a viscosity from 50 cP to 2000 cP, from 250 to 2000 cP, from 500 cP to 2000 cP, from 750 cP to 2000 cP, from 1000 cP to 2000 cP, from 1250 cP to 2000 cP, from 1500 cP to 2000 cP, or even from 1750 cP to 2000 cP.

[0022] Moreover, various neutralization levels are contemplated for the aqueous polyolefin dispersion, referring to the total acid units neutralized, the calculation of percent neutralization is based on the number of acid units considered to be present, based on the known amount of moles of the carboxylic acid containing comonomer and the number of mole equivalents of metal ions added. The aqueous polyolefin dispersion may be 85 mol.% neutralized, or between 80% and 90 mol.% neutralized. All individual values and subranges are included and disclosed herein. For example, the aqueous polyolefin dispersion may be 60% to 90 mol.% neutralized, 62% to 90 mol.% neutralized, 64% to 90 mol.% neutralized,66% to 90 mol.% neutralized, 68% to 90 mol.% neutralized, 70% to 90 mol.% neutralized,72% to 90 mol.% neutralized, 74% to 90 mol.% neutralized, 76% to 90 mol.% neutralized,78% to 90 mol.% neutralized, 80% to 90 mol.% neutralized, 82% to 90 mol.% neutralized,84% to 90 mol.% neutralized, 86% to 90 mol.% neutralized, 88% to 90 mol.% neutralized,60% to 85 mol.% neutralized, 60% to 80 mol.% neutralized, 60% to 75 mol.% neutralized,60% to 70 mol.% neutralized, 60% to 65 mol.% neutralized, 80% to 85 mol.% neutralized,82% to 85 mol.% neutralized, or even 84% to 85 mol.% neutralized.

[0023] Ethylene Acid Copolymer Dispersant

[0024] The ethylene acid copolymer dispersant comprises an ethylene acid copolymer, and the ethylene acid copolymer comprises the polymerized reaction product of 88.5 to 93.5 mol.% ethylene and 6.5 to 11.5 mol.% carboxylic acid containing comonomer based on the total moles of monomers present in the dispersant. Various carboxylic acid containing comonomers may be utilized in the ethylene acid copolymers. For example, the carboxylic acid containing comonomer may comprise a monocarboxylic acid, which may include acrylicacid, methacrylic acid, or both. In further embodiments, the ethylene acid copolymer dispersant may have carboxylic acid-containing comonomer ranging from a lower limit of6.5, 6.7, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, or 11 mol.% to an upper limit of 7.0, 7.5, 8.0,8.5, 9.0, 9.5, 9.8, 10, 10.5, 11.0, or 11.5 mol.%. The ethylene acid copolymer may be polymerized according to processes disclosed in U.S. Pat. Nos. 3,404,134; 5,028,674; 6,500,888; and 6,518,365. In some embodiments, blends of two or more ethylene acid copolymers may be used, provided that the aggregate components and properties of the blend fall within the limits described above for the ethylene acid copolymers.

[0025] Moving from mole percent to weight percent, the ethylene acid copolymer dispersant comprises the polymerized reaction product of 75 wt.% to 82 wt.% ethylene and 18 wt.% to 25 wt.% carboxylic acid-containing comonomer, based on the total weight of monomers present in the ethylene acid copolymer dispersant. In further embodiments, the ethylene acid copolymer dispersant may have carboxylic acid-containing comonomer ranging from a lower limit of 18, 19, 20, 21, 22, 23, or 24 wt.% to an upper limit of 19, 20, 21, 22, 23, 24, or 25 wt.%.

[0026] The melt index (b) of the ethylene acid copolymer dispersant ranges from 25 to 500 g / 10 min as determined according to ASTM D1238 (at 190 °C, 2.16 kg). In other embodiments, the melt index of the ethylene acid copolymer ranges may be from 25 to 100 g / 10 min, from 40 to 100 g / 10 min, or from 50 to 70 g / 10 min. All individual values and subranges are contained herein. The ethylene acid copolymer dispersant is not partially neutralized until the emulsification step, as described below.

[0027] Moreover, the ethylene acid copolymer dispersant may have a density from 0.910 to 0.975 g / cc, from 0.920 to 0.970 g / cc, or from 0.930 to 0.960 g / cc.

[0028] Ionomer. Dopant

[0029] The ionomer dopant is an ethylene acid copolymer that is partially neutralized by metal cations. The ethylene acid copolymer in the ionomer dopant is the polymerized reaction product of 93.0 to 98.5 mol.% ethylene and 1.5 to 7.0 mol.% carboxylic acid containing comonomer, based on the total moles of monomers present in the ethylene acid copolymer. In further embodiments, the ethylene acid copolymer in the ionomer dopant may havecarboxylic acid-containing comonomer ranging from a lower limit of 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, or 6.5 mol.% to an upper limit of 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, or 7.0 mol.%. Without being limited by theory, the ionomer dopant has a lower acid (i.e., carboxylic acid containing comonomer) content than the ethylene acid copolymer dispersant and it has been found that this lower acid content in the ionomer dopant assists the ethylene acid copolymer dispersant in producing a stabilized aqueous polyolefin dispersion.

[0030] Moving from mole percent to weight percent, the ethylene acid copolymer in the ionomer dopant may have from 86 to 95 wt. % of ethylene; and from 5 to 14 wt. % carboxylic acid containing comonomer, based on the total weight of monomers present in the ionomer dopant. In further embodiments, the ethylene acid copolymer in the ionomer dopant may have carboxylic acid-containing comonomer ranging from a lower limit of 5, 6, 7, 8, 9, 10, 11, 12, or 13 wt.% to an upper limit of 6, 7, 8, 9, 10, 11, 12, 13, or 14 wt.%

[0031] Like the above dispersant discussion, the ethylene acid copolymer of the ionomer dopant may be polymerized according to processes disclosed in U.S. Pat. Nos. 3,404,134; 5,028,674; 6,500,888; and 6,518,365. In some embodiments, blends of two or more ethylene acid copolymers may be used, provided that the aggregate components and properties of the blend fall within the limits described above for the ethylene acid copolymers.

[0032] Various carboxylic acid containing comonomers may be utilized in the ethylene acid copolymers. For example, the carboxylic acid containing comonomer may comprise a monocarboxylic acid, which may include acrylic acid, methacrylic acid, or both.

[0033] As noted above, the ethylene acid copolymer is already partially neutralized by a metal cation (to form an ionomer) at the point when incorporated into the polymer melt blend to make the dispersion. Cations may include, but are not limited to, sodium, zinc, potassium, lithium, magnesium, calcium, aluminum, or combinations thereof. Referring to the total acid units neutralized, the calculation of percent neutralization is based on the number of acid units considered to be present, based on the known amount of moles of the carboxylic acid containing comonomer and the number of mole equivalents of metal ions added. In embodiments herein, from 5 mole % to 70 mole % of total acid units of the ethylene acid copolymer are neutralized by a metal cation. All individual values and subranges are included and disclosed herein. In further embodiments, from 10 mole % to 70 mole %, from 20 mole% to 70 mole %, from 30 mole % to 70 mole %, from 20 mole % to 60 mole %, or from 30 mole % to 50 mole % of total acid units may be neutralized.

[0034] After neutralization, the partially neutralized ionomer dopant may have a melt index (I2) from 0.5 to 50 g / 10 min as determined according to ASTM D1238 (at 190 °C, 2.16 kg). All individual values and subranges are included and disclosed herein. For example, in some embodiments, the ionomer dopant may have a melt index (I2) from 0.5 to 45 g / 10 min, from 1 to 20 g / 10 min, from 1 to 10 g / 10 min, or from 1 to 7 g / 10 min.

[0035] Moreover, the ionomer dopant may have a density from 0.910 to 0.975 g / cc, from 0.920 to 0.970 g / cc, or from 0.930 to 0.960 g / cc.

[0036] Polyolefin

[0037] As described above, the aqueous polyolefin dispersion described herein comprises a polyolefin. The polyolefin may be selected from the group consisting of polyethylene or polypropylene, or combinations thereof. In one embodiment, the polyolefin comprises polypropylene. In another embodiment, the polyolefin comprises propylene / ethylene copolymer.

[0038] Various densities are considered suitable for the polyolefin. In some embodiments described herein, the polyolefin may have a density of 0.850 g / cc to 0.975 g / cc. All individual values and subranges of at least 0.850 g / cc to 0.975 g / cc are included and disclosed herein. For example, in some embodiments, the polyolefin may have a density of 0.855 to 0.905 g / cc, 0.855 to 0.900 g / cc, 0.855 to 0.900 g / cc, or 0.865 to 0.895 g / cc. Density may be measured in accordance with ASTM D792.

[0039] In one or more polypropylene embodiments as measured according to ASTM D- 1238, Procedure B (condition 230°C / 2.16 kg), the melt flow rate may be less than 10 g / 10 min, or less than 6 g / 10 min. In further embodiments, the polypropylene may have a melt flow rate of 0.5 to 75 g / 10 min, 1.0 to 50 g / 10 min, 2.0 to 25.0 g / 10 min, 5.0 to 15.0 g / 10 min, or from 7 to 10.0 g / 10 min.

[0040] In one or more polyethylene embodiments as measured in accordance with ASTM D-1238, Procedure B (condition 190°C / 2.16 kg), the polyethylene may have a melt index (I2)of 0.1 to 100 g / 10 mins, 0.5 to 75 g / 10 min, 1.0 to 50 g / 10 min, 2.0 to 25.0 g / 10 min, 2.5 to 10.0 g / 10 min, or from 2.5 to 7.5 g / 10 min. All individual values and subranges are disclosed herein.

[0041] Additional Additives

[0042] The aqueous polyolefin dispersion may contain other optional additives known in the art. Exemplary additives may include, but are not limited to, antioxidants, processing aids, flow enhancing additives, lubricants, pigments, dyes, flame retardants, impact modifiers, nucleating agents, anti-blocking agents such as silica, thermal stabilizers, UV absorbers, UV stabilizers, surfactants, chelating agents, and coupling agents. Additives can be used in the amount ranging from 0.0001 to 5 wt. % based on the weight of the total resin solids content in the aqueous polyolefin dispersion.

[0043] Methods

[0044] As previously noted above, the ethylene acid copolymer dispersant, the partially neutralized ionomer dopant, and one or more polyolefins are melt blended to produce a polymer melt blend. The polymer melt blend is emulsified in the presence of water and additional base to produce an emulsion. During the emulsification, the additional base further neutralizes acid units of the ethylene acid copolymer dispersant and may also further neutralize acid units of the partially neutralized ionomer dopant. Various bases are considered suitable for the neutralization step. In one embodiment, the base is an inorganic base such as potassium hydroxide, or sodium hydroxide. Additionally, organic bases such as amines, and ammonia are also suitable. In embodiments, the additional base may comprise multiple bases or a single base. Mixing of the polymer melt blend with the water and base may take place at a temperature of from 100 °C to 250 °C. A further optional step after dilution may include cooling the heated aqueous polyolefin dispersion to a temperature of 20-30 °C, wherein the ionomer remains dispersed in the liquid phase. Then, the emulsion is diluted with additional water to produce the aqueous polyolefin dispersion.

[0045] Uses

[0046] The aqueous polyolefin dispersions described herein may be used to coat a substrate, such as, flooring, plastic parts, wood, textiles, metal, ceramic, fibers, glass, or paper. Suitablesubstrates may include paperboard, cardboard, pulp-molded shape, woven fabric, nonwoven fabric, film, open-cell foam, closed-cell foam, or metallic foil. In some embodiments herein, a method for coating a substrate comprises: providing an aqueous polyolefin dispersion as described in embodiments herein, applying the aqueous polyolefin dispersion to the substrate to form a coated substrate. Applying may be performed by a dipping method, a spray method, a roll coating method, a doctor blade method, a flow coating method, or other suitable methods for applying liquid coatings that are known in the art. The method may further comprise a drying step.

[0047] In other embodiments herein, a method of forming a coated article comprises coating the aqueous polyolefin dispersion as described in one or more embodiments herein onto a substrate to form a coated substrate; and drying the coated substrate to form a coated article.

[0048] The aqueous polyolefin dispersion may be utilized in various applications, for example, in water barrier applications, gas barrier applications, oil and grease barrier coatings, heat seal coatings, artificial turf, etc.TEST METHODS

[0049] Density

[0050] Density was measured in accordance with ASTM D-792 and reported in grams per cubic centimeter (g / cc).

[0051] Melt.Index..(l2).

[0052] For ethylene-based polymers, melt index (I2) was measured in accordance with ASTM D-1238, Procedure B (condition 190°C / 2.16 kg) and reported in grams eluted per 10 minutes (g / 10 min).

[0053] Melt Flow Rate

[0054] For propylene-based polymers, melt flow rate was measured in accordance with ASTM D-1238, Procedure B (condition 230°C / 2.16 kg) and reported in grams eluted per 10 minutes (g / 10 min).

[0055] Mean Particle Size

[0056] Mean particle size is defined as the volume average particle diameter and was measured with a Beckman Coulter LS 13-320 Laser Light Scattering Particle Sizer (Beckman Coulter Inc., Fullerton, California) implementing an epoxy particle model (real fluid refractive index = 1.332, real sample refractive index = 1.5, imaginary sample refractive index = 0). The samples were diluted into an aqueous KOH solution with pH >10 before measuring.

[0057] Dynamic Vi scosity

[0058] Dynamic viscosity was measured via a Brookfield DVII+ instrument with an RV3 spindle. The spindle is submerged in the dispersion to the level line on the spindle at an appropriate rpm to obtain a stable viscosity reading for 15 seconds.

[0059] Processability Factor

[0060] The Processability Factor is defined by plotting a curve of particle size (y-axis) versus initial aqueous / polymer ratio (x-axis), and then by calculating the width of the curve at particle size < 2.0 microns. It is calculated by subtracting the lowest measured value on the x-axis of the graph where the particle size on the y-axis on the graph is less than 2.0 microns from the highest measured value on the x-axis of the graph where the particle size on the y-axis on the graph is less than 2.0 microns. To illustrate how the calculation is performed, FIG. 1, which depicts graphical plots of particle size versus initial aqueous / polymer ratio for Inventive Examples 2 and 3 is provided. The data for FIG. 1 are shown below in the following Tables 1 and 2.Table 1 - Data for FIG. 1, Inventive Example 2Table 2 - Data for FIG. 1, Inventive Example 3EXAMPLES

[0061] The aqueous polyolefin dispersion examples were prepared using a Berstorf (KraussMaffei) twin screw extruder having a 48 L / D and 25 mm screw diameter. The polyolefin resin (VERSIFY™ 3200), ethylene acid copolymer dispersant, and partially neutralized ionomer dopant of Table 3 were supplied to the feed throat of the extruder via a Schneck Mechatron loss-in-weight feeder and a K-Tron pellet feeder, respectively. The polyolefin resin, the ethylene acid copolymer dispersant, and the partially neutralized ionomer dopant were melt blended to form a polymer melt blend. The polymer melt blend was then emulsified in the presence of an initial aqueous stream and further neutralized with additional base (KOH) to form an emulsion phase. The initial aqueous feed, and additional base are supplied at the rates shown in Table 4 and are injected using ISCO syringe pumps (from Teledyne Isco, Inc., Lincoln NE, USA). The emulsion phase was then conveyed forward to a dilution and cooling zone of the extruder, where additional diluting water was added to the emulsion at the rates shown in Table 4 also by ISCO dual syringe pumps to form aqueous polyolefin dispersions having the solid level content shown in Table 5. The barrel temperature of the extruder was set to 150 °C and the extruder speed was 450 rpm. After the dispersion exited the extruder, it was allowed to cool to room temperature and then filtered via a 200 pm mesh size bag filter. The aqueous polyolefin dispersion examples had a final neutralization of 85 mol% of acid groups neutralized.

[0062] The ethylene acid copolymers were 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 in U.S. Pat. No. 4,351,931 (Armitage), which is hereby incorporated by reference. Other polymerization techniques are described in U.S. Pat. No. 5,028,674 (Hatch et al.) and U.S. Pat. No. 5,057,593 (Statz), both of which are also herebyincorporated by reference. Additional aspects of the ionomer are provided below in Table 1. The ionomers of these acid copolymers were prepared as stated above.

[0063] The base resin (VERSIFY™ 3200) and the dispersant blend (including the ionomer dopant) had a feed rate ratio of 5.7 to 1. The pellets of dispersant and dopant were blended together at ratio by weight of 99:1 in a “salt and pepper” fashion and fed together.

[0064] VERSIFY™ 3200, which is produced by Dow Inc., Midland, MI, is a plastomer having a density of 0.876 g / cc and a melt flow rate of 8 g / 10 min according to ASTM D1238 (230°C / 2.16 kg).

[0065] Ionomer l is a sodium ionomer, the sodium ionomer being comprised of an ethylene acid copolymer comprising 3.49 wt% methacrylic acid. Ionomer 1 has a melt index (h) of 1.3 g / 10 min according to ASTM D1238 (190 °C / 2.16 kg).

[0066] Ionomer 2 is a zinc ionomer, the zinc ionomer being comprised of an ethylene acid copolymer comprising 5.44 wt.% methacrylic acid. Ionomer 2 has a melt index (I2) of 5.5 g / 10 min according to ASTM D1238 (190°C / 2.16 kg).

[0067] Ethylene acid copolymer 1 (EAC 1) is a copolymer of ethylene and 7.1 mol.% methacrylic acid having a melt index (I2) of 60 g / 10 min according to ASTM DI 238 (190°C / 2.16 kg).

[0068] Ethylene acid copolymer 2 (EAC 2) is a copolymer of ethylene and 3.0 mol.% methacrylic acid having a melt index (I2) of 10 g / 10 min according to ASTM DI 238 (190°C / 2.16 kg).Table 3: Properties of Polyolefins, Dispersants, and DopantsTable 4: Processing ConditionsTable 5: Properties of Polyolefin Dispersion

[0069] In Table 5, samples that formed robustly processable dispersions are denoted as having a processability factor > 0. A processability factor of 0 means that a dispersion was possible to form, but only at one tested condition of initial aqueous to polymer ratio, which is an indication that this dispersion would not be robust to different processing conditions.

[0070] As shown by the dispersion results in Table 5 above, Comparative Example 1, which did not contain a dopant, did not form an aqueous polyolefin dispersion with a high processability factor. A high processability factor, which is also indicative of a broad processability window, denotes a dispersion with a small particle size is formed using a wide range of initial aqueous / polymer ratios, as opposed to only being formed at one particular ratio. This is an indicator that the formulation is more resistant to small variations in the process. Comparative Example 4, which included a non-neutralized ethylene acid copolymer dopant instead of an ionomer dopant, was processable (as its processability factor was >0), but the formed dispersion was not stable.

[0071] The Inventive Examples formed dispersions that were all processable, contained fine particles with an average particle size < 2 pm, and a processability factor above 0.02 indicating a high processability factor.

[0072] It will be apparent to persons of ordinary skill in the art that various modifications and variations can be made without departing from the scope disclosed herein. Since modifications, combinations, sub-combinations, and variations of the disclosed embodiments, which incorporate the spirit and substance disclosed herein, may occur to persons of ordinary skill in the art, the scope disclosed herein should be construed to include everything within the scope of the appended claims and their equivalents.

[0073] For the purposes of defining the present technology, the transitional phrase “consisting of’ may be introduced in the claims as a closed preamble term limiting the scope of the claims to the recited components or steps and any naturally occurring impurities. For the purposes of defining the present technology, the transitional phrase “consisting essentially of’ may be introduced in the claims to limit the scope of one or more claims to the recited elements, components, materials, or method steps as well as any non-recited elements, components, materials, or method steps that do not materially affect the novel characteristics of the claimed subject matter. The transitional phrases “consisting of’ and “consistingessentially of’ may be interpreted to be subsets of the open-ended transitional phrases, such as “comprising” and “including,” such that any use of an open ended phrase to introduce a recitation of a series of elements, components, materials, or steps should be interpreted to also disclose recitation of the series of elements, components, materials, or steps using the closed terms “consisting of’ and “consisting essentially of.” For example, the recitation of a composition “comprising” components A, B, and C should be interpreted as also disclosing a composition “consisting of’ components A, B, and C as well as a composition “consisting essentially of’ components A, B, and C. Any quantitative value expressed in the present application may be considered to include open-ended embodiments consistent with the transitional phrases “comprising” or “including” as well as closed or partially closed embodiments consistent with the transitional phrases “consisting of’ and “consisting essentially of.”

[0074] As used in the Specification and appended Claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly indicates otherwise. The verb “comprises” and its conjugated forms should be interpreted as referring to elements, components or steps in a non-exclusive manner. The referenced elements, components or steps may be present, utilized or combined with other elements, components or steps not expressly referenced.

[0075] It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure. The subject matter disclosed herein has been described in detail and by reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or feature is essential to the particular embodiment or to any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

CLAIMS1. An aqueous polyolefin dispersion comprising polymer solid particles dispersed in water, wherein the polymer solid particles comprise: polyolefin; ethylene acid copolymer dispersant, wherein the ethylene acid copolymer dispersant comprises the polymerized reaction product of 88.5 to 93.5 mol.% ethylene and 6.5 to 11.5 mol.% carboxylic acid containing comonomer based on the total moles of monomers present in the ethylene acid copolymer dispersant, wherein the ethylene acid copolymer dispersant has a melt index (h) from 15 to 500 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg); and at least partially neutralized ionomer dopant, which comprises an ethylene acid copolymer, wherein the ethylene acid copolymer comprises the polymerized reaction product of 93.0 to 98.5 mol.% ethylene and 1.5 to 7.0 mol.% carboxylic acid containing comonomer, based on the total moles of monomers present in the partially neutralized ionomer dopant, wherein the partially neutralized ionomer dopant has a melt index (I2) from 0.5 to 50 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg), and wherein from 10 to 70 % of total acid units of the partially neutralized ionomer dopant are neutralized by metal cations; wherein the ratio by weight of ethylene acid copolymer dispersant to partially neutralized ionomer dopant is from 200: 1 to 10: 1.

2. The aqueous polyolefin dispersion of claim 1, wherein the carboxylic acid containing comonomer comprises methacrylic acid, acrylic acid, or combinations thereof.

3. The aqueous polyolefin dispersion of claim 1 or 2, wherein the ratio by weight of dispersant to dopant is from 150: 1 to 50: 1.

4. The aqueous polyolefin dispersion of any one of claims 1 to 3, wherein the aqueous polyolefin dispersion comprises 30 to 60 wt.% of the polymer solid particles, or from 40 to 50 wt.% of the polymer solid particles.

5. The aqueous polyolefin dispersion of any one of claims 1 to 4, wherein the polymer solid particles have an average particle size of less than or equal to 2 pm.

6. The aqueous polyolefin dispersion of any one of claims 1 to 5, wherein the metal cation comprises sodium, zinc, or combinations thereof.

7. The aqueous polyolefin dispersion of any one of claims 1 to 6, wherein the melt index (I2) of the ethylene acid copolymer dispersant is from 15 to 90 dg / min, or from 50 to 70 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg).

8. The aqueous polyolefin dispersion of any one of claims 1 to 7, wherein the melt index (I2) of the partially neutralized ionomer dopant is from 0.5 to 10 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg).

9. The aqueous polyolefin dispersion of any one of claims 1 to 8, wherein the polyolefin comprises ethylene / alpha-olefin copolymer having a melt index (I2) of 0.1 to 100.0 g / 10 min as determined according to ASTM D1238 (at 190 °C 2.16 kg).

10. The aqueous polyolefin dispersion of any one of claims 1 to 8, wherein the polyolefin comprises propylene / ethylene copolymer having a melt flow rate of 0.5 to 75 g / 10 min as determined according to ASTM D-1238, Procedure B (condition 230°C / 2.16 kg).

11. The aqueous polyolefin dispersion of any one of claims 1 to 8, wherein the polyolefin is selected from the group consisting of polyethylene or polypropylene.

12. A method of producing an aqueous polyolefin dispersion comprising: melt blending polyolefin, ethylene acid copolymer dispersant, and partially neutralized ionomer dopant to produce a polymer melt blend, wherein the ethylene acid copolymer dispersant comprises an ethylene acid copolymer, wherein the ethylene acid copolymer comprises the polymerized reaction product of 88.5 to 93.5 mol.% ethylene and 6.5 to 11.5 mol.% carboxylic acid containing comonomer based on the total weight of monomers present in the ethylene acid copolymer dispersant, wherein the ethylene acid copolymer dispersant has a melt index (12) from 25 to 500 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg); and at least partially neutralized ionomer dopant, which comprises an ethylene acid copolymer, wherein the ethylene acid copolymer comprises the polymerized reaction product of 93.0 to 98.5 mol.% ethylene and 1.5 to 7.0mol.% carboxylic acid containing comonomer, based on the total weight of monomers present in the partially neutralized ionomer dopant, wherein the partially neutralized ionomer dopant has a melt index (I2) from 0.5 to 50 dg / min as determined according to ASTM D1238 (at 190 °C, 2.16 kg), and wherein 10 to 70% of total acid units of the partially neutralized ionomer dopant are neutralized by metal cations; and the ratio by weight of part of ethylene acid copolymer dispersant to partially neutralized ionomer dopant is from 200: 1 to 10: 1; emulsifying the polymer melt blend in the presence of water and additional base to produce an emulsion, wherein the additional base further neutralizes at least a fraction of the acid units of the ethylene acid copolymer dispersant; and diluting the emulsion with additional water to produce the aqueous polyolefin dispersion.

13. The method of claim 12, wherein the additional base comprises KOH.

14. The aqueous polyolefin dispersion produced by the method of claims 12 or 13.

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