Aqueous polyolefin dispersion containing an ionomer dopant and method for producing the same

Abstract

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

Description

Technical Field

[0001] (Cross-Reference to Related Application) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 579,619 filed on August 30, 2023, the entire content of which is incorporated herein by reference.

[0002] (Field of the Invention) Embodiments disclosed herein generally relate to methods for preparing aqueous polyolefin dispersions, and more specifically to aqueous polyolefin dispersions comprising an ionomer as a dopant. Background Art

[0003] Ethylene acrylic acid (EAA) and ethylene methacrylic acid (EMAA) copolymers are generally used as dispersants in the preparation of dispersions of various polyolefin polymers. When used in such dispersions, EAA / EMAA copolymers often fail to achieve robust and stable polyolefin resin dispersions, particularly when the EAA or MAA content is not sufficiently high.

[0004] Accordingly, there remains a need for improved EAA or EMAA dispersants for preparing processable and stable aqueous polyolefin dispersions. Summary of the Invention

[0005] Embodiments of the present disclosure satisfy 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 dopant to form a polymer melt blend. Surprisingly, without being bound by theory, it was found that including a partially neutralized ionomer dopant enables better dispersion of the polymer blend and results in a more stable dispersion.

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

[0007] One or more embodiments of this disclosure provide a method for producing an aqueous polyolefin dispersion. This method comprises 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, which comprises a polymerization 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) of 25 to 500 dg / min, as determined according to ASTM D1238 (at 190°C, 2.16 kg). This method further comprises providing at least a partially neutralized ionomer dopant comprising an ethylene acid copolymer, which comprises a polymerization 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. The dopant has a melt index (I2) of 0.5 to 50 dg / min, as determined according to ASTM D1238 (at 190°C, 2.16 kg). Furthermore, 10 to 70 mol% of the total acid units of the dispersant are neutralized by metal cations, and the weight ratio of dispersant to dopant is 200:1 to 10:1. In further embodiments, the weight ratio is 150:1 to 50:1, or 125:1 to 75:1. The method further comprises emulsifying a polymer melt blend in the presence of water and an additional base to produce an emulsion, wherein the additional base further neutralizes some or all of the acid units of the ethylene acid copolymer dispersant, and diluting the emulsion with additional water to produce an aqueous polyolefin dispersion.

[0008] It should be understood that both the general description above and the detailed description below describe various embodiments and are intended to provide an overview or framework for understanding the nature and features of the claimed subject matter. Additional features and advantages of the embodiments are described in the detailed description, some of which will be readily apparent to those skilled in the art from the description, including the accompanying drawings and claims, or will be 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 illustrate the principles and operation of the claimed subject matter. However, the embodiments are in essence illustrative and exemplary and are not intended to limit the claimed subject matter. [Brief explanation of the drawing]

[0009] The following detailed description of specific embodiments of this disclosure can be best understood in conjunction with the following drawings. [Figure 1] This graph illustrates the calculation of the processability coefficient according to Examples 2 and 3 of the present invention, which will be explained in more detail in the following examples. [Modes for carrying out the invention]

[0010] Herein, specific embodiments of this application are described. These embodiments are provided so as to ensure that this disclosure is detailed and complete, and so as to fully convey the scope of the subject matter to those skilled in the art.

[0011] The term "polymer" refers to polymer compounds prepared by polymerizing monomers, whether of the same or different types. Therefore, the general term "polymer" typically includes the term "homopolymer," which refers to polymers prepared from only one type of monomer, and the term "copolymer," which refers to polymers prepared from two or more different monomers. As used herein, the term "interpolymer" refers to polymers prepared by polymerizing at least two different types of monomers. Therefore, the general term "interpolymer" includes copolymers or polymers prepared from more than two different types of monomers, such as terpolymers.

[0012] "Polyethylene" or "ethylene polymer" means a polymer containing units derived from more than 50 mol% of ethylene monomers. This includes ethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of ethylene polymers known in the art include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (ULDPE), very low-density polyethylene (VLDPE), single-site catalyst linear low-density polyethylene (m-LLDPE) including both linear low-density resins and substantially linear low-density resins, medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0013] "Polypropylene" or "propylene polymer" means a polymer containing more than 50 mol% of units derived from propylene monomer. This includes propylene homopolymers or copolymers (meaning that the units are derived from two or more comonomers). Common forms of propylene 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.

[0014] "Ethylene acid copolymer" is a polymerization reaction product of ethylene and one or more unsaturated carboxylic acids.

[0015] As used herein, “dispersion” and related terms refer to solid particles, such as polymer particles, suspended in an aqueous liquid phase. Furthermore, as used herein, “dispersant” refers to a copolymer intended to maintain the suspension of polymer particles in an aqueous liquid phase.

[0016] Embodiments of this disclosure relate to systems and methods for producing aqueous polyolefin dispersions using an ethylene acid copolymer dispersant and a partially neutralized ionomer dopant. The ethylene acid copolymer dispersant comprises a polymerization product of 88.5 to 93.5 mol% ethylene and 6.5 to 11.5 mol% carboxylic acid-containing comonomers, based on the total moles of monomers present in the ethylene acid copolymer dispersant. The partially neutralized ionomer dopant comprises an ethylene acid copolymer, which comprises a polymerization product of 93.0 to 98.5 mol% ethylene and 1.5 to 7.0 mol% carboxylic acid-containing comonomers, based on the total moles of monomers present in the ethylene acid copolymer, of which 10 to 70 mol% of the acid units are neutralized by metal cations. An ethylene acid copolymer dispersant, a partially neutralized ionomer dopant, and one or more polyolefins are melt-blended to produce a polymer melt blend. The polymer melt blend is then emulsified in the presence of water and an additional base to produce an emulsion, the additional base further neutralizing the acid units of the partially neutralized ionomer. The emulsion is then diluted with additional water to produce an aqueous polyolefin dispersion.

[0017] Aqueous polyolefin dispersion In embodiments of this specification, aqueous polyolefin dispersions may contain a total resin solids content of 30–60% by weight, or 40–50% by weight. All individual values ​​and partial ranges are included and disclosed herein. As used herein, the total resin solids content consists of an ethylene acid copolymer dispersant (at least after partial neutralization), an ionomer dopant, a polyolefin, and optionally some alkali metal cation-containing base. Various amounts are possible within the total resin solids content. There may be 70%–90% by weight of polyolefin, 5%–30% by weight of dispersant, and less than 5% by weight of dopant. In further embodiments, there may be 80%–90% by weight of polyolefin, 10%–20% by weight of dispersant, and 0.01–1.5% by weight of dopant. In yet another embodiment, there may be 60%–70% by weight of polyolefin, 30%–40% by weight of dispersant, and 0.01–1.5% by weight of dopant.

[0018] Particles present in an aqueous polyolefin dispersion may have an average particle diameter of 2.00 μm or less, or less than 1.50 μm. All individual values ​​and subranges are included and disclosed herein. For example, an aqueous polyolefin dispersion may have an average particle diameter of 0.1–1.50 μm, 0.50–1.50 μm, 0.75–1.50 μm, 0.80–1.40 μm, or 0.80–1.30 μm. Without being limited by theory, when the particle diameter exceeds 2.0 μm, the particles tend not to maintain colloidal stability, i.e., they remain suspended in the aqueous phase, and furthermore, when the average particle diameter is 1.50 μm or less, colloidal stability tends to improve.

[0019] Aqueous polyolefin dispersions can have a variety of viscosities. They may have viscosities ranging from 45 cP to 70 cP or 50 cP to 65 cP. All individual values ​​and subranges are included and disclosed herein. For example, aqueous polyolefin dispersions may have viscosities of 50 cP to 2000 cP, 250 to 2000 cP, 500 cP to 2000 cP, 750 cP to 2000 cP, 1000 cP to 2000 cP, 1250 cP to 2000 cP, 1500 cP to 2000 cP, or even 1750 cP to 2000 cP.

[0020] Furthermore, various levels of neutralization are possible for aqueous polyolefin dispersions, and the calculation of the neutralization rate is based on the number of acid units that are thought to be present, based on the molar amount of known carboxylic acid-containing comonomers and the molar equivalents of added metal ions, with reference to the total acid units neutralized. Aqueous polyolefin dispersions can be neutralized to 85 mol% or 80 mol% to 90 mol%. All individual values ​​and subranges are included and disclosed herein. For example, aqueous polyolefin dispersions can be neutralized to 60% to 90 mol%, 62% to 90 mol%, 64% to 90 mol%, 66% to 90 mol%, 68% to 90 mol%, 70% to 90 mol%, 72% to 90 mol%, 74% to 90 mol%, 76% to 90 mol%, 78% to 90 mol%, 80% to 90 mol%, and 8 Neutralization may occur at 2%-90 mol%, 84%-90 mol%, 86%-90 mol%, 88%-90 mol%, 60%-85 mol%, 60%-80 mol%, 60%-75 mol%, 60%-70 mol%, 60%-65 mol%, 80%-85 mol%, 82%-85 mol%, or even 84%-85 mol%.

[0021] Ethylene acid copolymer dispersant The ethylene acid copolymer dispersant comprises an ethylene acid copolymer, which comprises a polymerization 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 can be used in the ethylene acid copolymer. For example, the carboxylic acid-containing comonomer may include monocarboxylic acids that may contain acrylic acid, methacrylic acid, or both. In further embodiments, the ethylene acid copolymer dispersant may have carboxylic acid-containing comonomers ranging from a lower limit of 6.5, 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%. Ethylene acid copolymers can be polymerized according to the processes disclosed in U.S. Patents 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 range described above for ethylene acid copolymers.

[0022] Converting from mole percent to weight percent, the ethylene acid copolymer dispersant contains a polymerization reaction product of 75% to 82% by weight of ethylene and 18% to 25% by weight of carboxylic acid-containing comonomers, 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 comonomers ranging from a lower limit of 18, 19, 20, 21, 22, 23, or 24% by weight to an upper limit of 19, 20, 21, 22, 23, 24, or 25% by weight.

[0023] When determined in accordance with ASTM D1238 (at 190°C under a load of 2.16 kg), the melt index (I₂) of the ethylene acid copolymer dispersant is in the range of 25 to 500 g / 10 min. In other embodiments, the melt index of the ethylene acid copolymer may range from 25 to 100 g / 10 min, 40 to 100 g / 10 min, or 50 to 70 g / 10 min. All individual values and subranges are included herein. The ethylene acid copolymer dispersant is not partially neutralized prior to the emulsification step, as described below.

[0024] Further, the ethylene acid polymer dispersant may have a density of 0.910 to 0.975 g / cc, 0.920 to 0.970 g / cc, or 0.930 to 0.960 g / cc.

[0025] Ionomer dopant The ionomer dopant is an ethylene acid copolymer partially neutralized by metal cations. The ethylene acid copolymer in the ionomer dopant is a polymerization reaction product of 93.0 to 98.5 mol% of ethylene and 1.5 to 7.0 mol% of a 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 comprise the carboxylic acid-containing comonomer in a range 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 bound by theory, it has been found that the ionomer dopant has a lower acid (i.e., carboxylic acid-containing comonomer) content than the ethylene acid copolymer dispersant, and this lower acid content in the ionomer dopant helps the ethylene acid copolymer dispersant produce a stabilized aqueous polyolefin dispersion.

[0026] When converted from mole percent to weight percent, the ethylene acid copolymer in the ionomer dopant may comprise 86 to 95 weight percent of ethylene and 5 to 14 weight percent of a 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 comprise a carboxylic acid-containing comonomer in a range from a lower limit of 5, 6, 7, 8, 9, 10, 11, 12, or 13 weight percent to an upper limit of 6, 7, 8, 9, 10, 11, 12, 13, or 14 weight percent.

[0027] Similar to the discussion of dispersants above, the ethylene acid copolymer of the ionomer dopant can be polymerized according to the processes disclosed in U.S. Pat. Nos. 3,404,134, 5,028,674, 6,500,888, and 6,518,365. In some embodiments, a blend of two or more ethylene acid copolymers may be used, provided that the aggregate components and properties of the blend fall within the ranges described above for ethylene acid copolymers.

[0028] Various carboxylic acid-containing comonomers may be used in the ethylene acid copolymer. For example, the carboxylic acid-containing comonomer may comprise a monocarboxylic acid, which may include acrylic acid, methacrylic acid, or both.

[0029] As described above, ethylene acid copolymers are already partially neutralized by metal cations (forming ionomers) when incorporated into a polymer melt blend to prepare a dispersion. Examples of cations include, but are not limited to, sodium, zinc, potassium, lithium, magnesium, calcium, aluminum, or combinations thereof. Referring to the total neutralized acid units, the calculation of the neutralization rate is based on the number of acid units that are thought to be present, given the molar amounts of known carboxylic acid-containing comonomers and the molar equivalents of the added metal ions. In embodiments herein, 5 mol% to 70 mol% of the total acid units of the ethylene acid copolymer are neutralized by metal cations. All individual values ​​and partial ranges are included and disclosed herein. In further embodiments, 10 mol% to 70 mol%, 20 mol% to 70 mol%, 30 mol% to 70 mol%, 20 to 60 mol%, or 30 to 50 mol% of the total acid units may be neutralized.

[0030] After neutralization, the partially neutralized ionomer dopant may have a melt index (I2) of 0.5 to 50 g / 10 min, as determined according to ASTM D1238 (at 190°C, 2.16 kg). All individual values ​​and partial ranges are included and disclosed herein. For example, in some embodiments, the ionomer dopant may have a melt index (I2) of 0.5 to 45 g / 10 min, 1 to 20 g / 10 min, 1 to 10 g / 10 min, or 1 to 7 g / 10 min.

[0031] Furthermore, ionomer dopant may have densities of 0.910-0.975 g / cc, 0.920-0.970 g / cc, or 0.930-0.960 g / cc.

[0032] Polyolefins As described above, the aqueous polyolefin dispersions described herein contain a polyolefin. The polyolefin may be selected from the group consisting of polyethylene, polypropylene, or a combination thereof. In one embodiment, the polyolefin contains polypropylene. In another embodiment, the polyolefin contains a propylene / ethylene copolymer.

[0033] A variety of densities are considered suitable for polyolefins. In some embodiments described herein, polyolefins may have densities ranging from 0.850 g / cc to 0.975 g / cc. At least all individual values ​​and subranges within the range of 0.850 g / cc to 0.975 g / cc are included and disclosed herein. For example, in some embodiments, polyolefins may have densities 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. Densities may be measured according to ASTM D792.

[0034] In one or more embodiments of polypropylene, the melt flow rate, when measured according to ASTM D-1238, Procedure B (conditions 230°C / 2.16 kg), may be less than 10 g / 10 min or less than 6 g / 10 min. In further embodiments, polypropylene may have melt flow rates 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 7 to 10.0 g / 10 min.

[0035] In one or more embodiments of polyethylene, when measured according to ASTM D-1238, Procedure B (conditions 190°C / 2.16 kg), the polyethylene may have melt indices (I2) of 0.1–100 g / 10 min, 0.5–75 g / 10 min, 1.0–50 g / 10 min, 2.0–25.0 g / 10 min, 2.5–10.0 g / 10 min, or 2.5–7.5 g / 10 min. All individual values ​​and partial ranges are disclosed herein.

[0036] Additional additives The aqueous polyolefin dispersion may contain other optional additives known in the art. Exemplary additives include, but are not limited to, antioxidants, processing aids, flow-enhancing additives, lubricants, pigments, dyes, flame retardants, impact-resistant agents, nucleating agents, anti-blocking agents such as silica, heat stabilizers, UV absorbers, UV stabilizers, surfactants, chelating agents, and coupling agents. Additives may be used in amounts ranging from 0.0001% to 5% by weight, based on the weight of the total resin solids content in the aqueous polyolefin dispersion.

[0037] method As described 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 an additional base to produce an emulsion. During emulsification, the additional base may further neutralize the acid units of the ethylene acid copolymer dispersant and also the 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. Organic bases such as amines and ammonia are also suitable. In embodiments, the additional base may consist of multiple bases or a single base. The mixing of the polymer melt blend with water and the base may be carried out at a temperature of 100°C to 250°C. A further optional step after dilution may include cooling the heated aqueous polyolefin dispersion to a temperature of 20 to 30°C, at which point the ionomer remains dispersed in the liquid phase. The emulsion is then diluted with additional water to produce an aqueous polyolefin dispersion.

[0038] Purpose The aqueous polyolefin dispersions described herein may be used to coat substrates such as floors, plastic parts, wood, textiles, metals, ceramics, fibers, glass, or paper. Suitable substrates may include cardboard, pulp-molded shapes, woven fabrics, nonwoven fabrics, films, open-cell foams, closed-cell foams, or metal foils. In some embodiments described herein, a method for coating a substrate comprises providing an aqueous polyolefin dispersion as described in the embodiments described herein, and applying the aqueous polyolefin dispersion to the substrate to form a coated substrate. The application may be carried out by dipping, spraying, roll coating, doctor blade, flow coating, or other suitable methods for applying liquid coatings known in the art. The method may further include a drying step.

[0039] In other embodiments of this specification, a method for forming a coated article includes coating a substrate with an aqueous polyolefin dispersion as described in one or more embodiments described herein to form a coated substrate, and drying the coated substrate to form a coated article.

[0040] Aqueous polyolefin dispersions can be used in a variety of applications, such as water barriers, gas barriers, oil and grease barrier coatings, heat seal coatings, and artificial turf.

[0041] Test method density Density is measured according to ASTM D-792 and reported in grams per cubic centimeter (g / cc).

[0042] Melt Index (I2) For ethylene-based polymers, the melt index (I2) is measured according to ASTM D-1238, Procedure B (conditions: 190°C / 2.16 kg) and reported as grams dissolved per 10 minutes (g / 10 min).

[0043] Meltflow rate For propylene polymers, the melt flow rate is measured according to ASTM D-1238, Procedure B (under conditions of 230°C / 2.16 kg) and reported as grams eluted per 10 minutes (g / 10 min).

[0044] Average particle size The average particle size is defined as the volume-average particle size measured using a Beckman Coulter LS 13-320 laser light scattering particle size analyzer (Beckman Coulter Inc., Fullerton, California) that implements an epoxy particle model (actual fluid refractive index = 1.332, actual sample refractive index = 1.5, virtual sample refractive index = 0). The sample is diluted in an aqueous KOH solution with pH > 10 before measurement.

[0045] Dynamic viscosity Dynamic viscosity was measured using a Brookfield DVII+ instrument equipped with an RV3 spindle. The spindle was submerged in the dispersion up to the level line on the spindle, and a stable viscosity reading was obtained for 15 seconds at an appropriate rpm.

[0046] Processability coefficient The processability coefficient is defined by plotting a curve between particle size (y-axis) and the initial aqueous solution / polymer ratio (x-axis), and then calculating the width of the curve for particle size < 2.0 microns. This is calculated by subtracting the lowest value on the x-axis of the graph where the particle size on the y-axis is less than 2.0 microns from the highest value on the x-axis of the graph where the particle size on the y-axis is less than 2.0 microns. To illustrate how the calculation is performed, Figure 1 is provided, showing graphs of particle size and the initial aqueous solution / polymer ratio for Examples 2 and 3 of the present invention. The data for Figure 1 are shown in Tables 1 and 2 below.

[0047] [Table 1]

[0048] [Table 2] [Examples]

[0049] Examples of aqueous polyolefin dispersions were prepared using a Bersterf (KraussMaffei) twin-screw extruder with a flow rate of 48 L / D and a screw diameter of 25 mm. The polyolefin resin (VERSIFY® 3200), ethylene acid copolymer dispersant, and partially neutralized ionomer dopant shown in Table 3 were fed into the extruder's feed port via a Schneck Mechatron loss-in-weight feeder and a K-Tron pellet feeder, respectively. The polyolefin resin, ethylene acid copolymer dispersant, and 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 were supplied at the rates shown in Table 4 and injected using an ISCO syringe pump (Teledyne Isco, Inc., Lincoln NE, USA). Subsequently, the emulsion phase was transported to the extruder's dilution and cooling zone, where additional dilution water was added to the emulsion by an ISCO dual syringe pump at the rates shown in Table 4 to form an aqueous polyolefin dispersion with the solid content levels shown in Table 5. The extruder barrel temperature was set to 150°C and the extruder speed was 450 rpm. After being discharged from the extruder, the dispersion was cooled to room temperature and then filtered through a 200 μm mesh bag filter. An example of the aqueous polyolefin dispersion had a final neutralization with 85 mol% of acidic groups neutralized.

[0050] Ethylene acid copolymers were prepared by a standard free radical copolymerization method carried out continuously under high pressure. Monomers are supplied to the reaction mixture in proportions related to the reactivity of the monomers and the desired amount of incorporation. 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 in U.S. Patent No. 4,351,931 (Armitage), which is incorporated herein by reference. Other polymerization techniques are described in U.S. Patent No. 5,028,674 (Hatch et al.) and U.S. Patent No. 5,057,593 (Statz), both of which are incorporated herein by reference. Additional embodiments of ionomers are provided in Table 1 below. Ionomers of these acid copolymers were prepared as described above.

[0051] The base resin (VERSIFY® 3200) and dispersant blend (containing ionomer dopant) had a feed rate ratio of 5.7:1. The pellets of dispersant and dopant were blended together in a 99:1 weight ratio using a "salt and pepper" method and fed together.

[0052] VERSIFY® 3200, manufactured by Dow Inc., Midland, MI, is a plastomer with 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).

[0053] Ionomer 1 is a sodium ionomer, which is composed of an ethylene acid copolymer containing 3.49% by weight of methacrylic acid. Ionomer 1 has a melt index (I2) of 1.3 g / 10 min according to ASTM D1238 (190°C / 2.16 kg).

[0054] Ionomer 2 is a zinc ionomer, which is composed of an ethylene acid copolymer containing 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).

[0055] 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 D1238 (190°C / 2.16 kg).

[0056] 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 D1238 (190°C / 2.16 kg).

[0057] [Table 3]

[0058] [Table 4]

[0059] [Table 5]

[0060] Table 5 indicates that samples forming a robustly processable dispersion have a processability coefficient > 0. A processability coefficient of 0 means that the dispersion can be formed, but only under one test condition of the initial aqueous solution-to-polymer ratio, indicating that this dispersion will not be robust under different processing conditions.

[0061] As shown in 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 coefficient. A high processability coefficient, which also represents a wide processability window, indicates that dispersions with small particle sizes are formed using a wide range of initial aqueous solution / polymer ratios, rather than being formed at only one specific ratio. This is an indicator that this formulation has better tolerance to small variations in the process. Comparative Example 4, which contained an unneutralized ethylene acid copolymer dopant instead of an ionomer dopant, was processable (its processability coefficient was >0), but the resulting dispersion was not stable.

[0062] All of the embodiments of the present invention are processable, contain fine particles with an average particle diameter of <2 μm, and form a dispersion with a processability coefficient exceeding 0.02, exhibiting a high processability coefficient.

[0063] It will be apparent to those skilled in the art that various modifications and changes are possible without departing from the scope disclosed herein. Since modifications, combinations, partial combinations, and variations of the disclosed embodiments incorporating the spirit and substance disclosed herein can be conceived by those skilled in the art, the scope disclosed herein should be construed as encompassing the entirety of the appended claims and their equivalents.

[0064] For the purpose of defining this technology, the transitional phrase "consisting of" may be introduced into the claims as a closed preamble term limiting the claims to the enumerated components or steps and any naturally occurring impurities. For the purpose of defining this technology, the transitional phrase "consisting essentially of" may be introduced into the claims to limit one or more claims to the described elements, components, materials, or method steps, and any undescribed elements, components, materials, or method steps that do not substantially affect the novel features of the claimed subject matter. The transitional phrases "consisting of" and "consisting essentially of" can be interpreted as a subset of open-ended transitional phrases such as "comprising" and "including," and consequently, any use of an open-ended phrase to introduce an enumeration of a set of elements, components, materials, or steps should also be interpreted as disclosing an enumeration of a set of elements, components, materials, or steps using the closed terms "consisting of" and "consisting essentially of." For example, a description of a composition "containing" components A, B, and C should also be interpreted as disclosing a composition "consisting of" components A, B, and C, as well as a composition "essentially consisting of" components A, B, and C. Any quantitative values ​​expressed in this application may be considered to include open-end embodiments that correspond to the transitional phrases “comprising” or “including,” as well as closed or partially closed embodiments that correspond to the transitional phrases “consisting of” and “consisting essentially of.”

[0065] In this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. The verb “comprises” and its conjugations should be interpreted as referring non-exclusively to elements, components, or steps. The elements, components, or steps being referenced may exist, be used, or be combined with other elements, components, or steps that are not explicitly referenced.

[0066] Any two quantitative values ​​assigned to a characteristic may constitute a range for that characteristic, and it should be understood that all combinations of ranges formed from all described quantitative values ​​of a given characteristic are contemplated in this disclosure. The subject matter disclosed herein is described in detail with reference to specific embodiments. It should be understood that no detailed description of any component or feature of an embodiment necessarily implies that such component or feature is essential to a particular embodiment or any other embodiment. Furthermore, it will be apparent to those skilled in the art that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

1. An aqueous polyolefin dispersion containing polymer solid particles dispersed in water, wherein the polymer solid particles are Polyolefins and An ethylene acid copolymer dispersant, wherein the ethylene acid copolymer dispersant comprises a polymerization 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, and the ethylene acid copolymer dispersant has a melt index (I) of 15 to 500 dg / min when determined according to ASTM D1238 (at 190°C, 2.16 kg). ２ An ethylene acid copolymer dispersant having ) A partially neutralized ionomer dopant comprising an ethylene acid copolymer, wherein the ethylene acid copolymer comprises a polymerization 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, and the partially neutralized ionomer dopant has a melt index (I) of 0.5 to 50 dg / min as determined according to ASTM D1238 (at 190°C, 2.16 kg). ２ The partially neutralized ionomer dopant comprises a ) having ), wherein 10 to 70% of the total acid units of the partially neutralized ionomer dopant are neutralized by metal cations, An aqueous polyolefin dispersion having a weight ratio of 200:1 to 10:1 between the ethylene acid copolymer dispersant and a partially neutralized ionomer dopant.

2. The aqueous polyolefin dispersion according to claim 1, wherein the carboxylic acid-containing comonomer comprises methacrylic acid, acrylic acid, or a combination thereof.

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

1.

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

5. The aqueous polyolefin dispersion according to any one of claims 1 to 4, wherein the polymer solid particles have an average particle diameter of 2 μm or less.

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

7. The melt index (I) of the ethylene acid copolymer dispersant. ２ The aqueous polyolefin dispersion according to any one of claims 1 to 6, wherein the concentration is 15 to 90 dg / min or 50 to 70 dg / min, as determined according to ASTM D1238 (at 190°C, 2.16 kg).

8. The melt index (I) of the partially neutralized ionomer dopant. ２ The aqueous polyolefin dispersion according to any one of claims 1 to 7, wherein the concentration is 0.5 to 10 dg / min when determined according to ASTM D1238 (at 190°C and 2.16 kg).

9. When the polyolefin is determined according to ASTM D1238 (at 190°C, 2.16 kg), the melt index (I) is 0.1 to 100.0 g / 10 min. ２ An aqueous polyolefin dispersion according to any one of claims 1 to 8, comprising an ethylene / alpha-olefin copolymer having ).

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

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

12. A method for producing an aqueous polyolefin dispersion, The process involves 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, the ethylene acid copolymer comprising a polymerization 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, and the ethylene acid copolymer dispersant has a melt index (I2) of 25 to 500 dg / min as determined according to ASTM D1238 (at 190°C, 2.16 kg). A partially neutralized ionomer dopant comprising an ethylene acid copolymer, wherein the ethylene acid copolymer comprises a polymerization 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 weight of monomers present in the partially neutralized ionomer dopant, and the partially neutralized ionomer dopant has a melt index (I) of 0.5 to 50 dg / min as determined according to ASTM D1238 (at 190°C, 2.16 kg). ２ ) and 10 to 70% of the total acid units of the partially neutralized ionomer dopant are neutralized by metal cations, The process involves producing a polymer melt mixture in which the weight ratio of the ethylene acid copolymer dispersant to the partially neutralized ionomer dopant is 200:1 to 10:

1. The polymer melt blend is emulsified in the presence of water and an additional base to produce an emulsion, wherein the additional base further neutralizes at least a portion of the acid units of the ethylene acid comonomer dispersant to produce the emulsion. A method comprising diluting the emulsion with additional water to produce the aqueous polyolefin dispersion.

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

14. An aqueous polyolefin dispersion produced by the method described in claim 12 or 13.

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