Field

The present invention relates to packages having inner surfaces that facilitate the release of flowable products such as liquids.

Background

Product retention in packaging in various applications such as personal care, food, beverage, and household products results in product waste and lessens consumer value. Improved product release can result in less product waste as well as less container waste. Furthermore, improved product release characteristics could reduce recycling costs where retained products must be removed prior to recycling. In addition, improved product release characteristics would give product manufacturers more formulation flexibility, allowing them to introduce more viscous and/or higher solids products. There remains a need for packages having improved product release characteristics and other properties.

Summary

The present invention advantageously provides packages that provide desirable release or evacuation of products (e.g., liquids) contained therein. Packages that provide improved release of products can result in a number of advantages. For example, in some embodiments, packages of the present invention can provide a reduction in waste, value to consumers due to the retrieval of more product from the package, reduction in recycling costs, and other advantages.

In one embodiment, a package of the present invention comprises an inner surface comprising a polyalkylene ether modified polyolefin. In one embodiment, the polyalkylene ether modified polyolefin comprises:

where R, R _l5 R ₂ , R ₃ , and R4 independently comprise H or alkyl, where PO represents an olefin or alpha olefin monomer repeat unit, where x +y + z = 100 mole percent, and where n + m = 100 mole percent. In some embodiments, x ranges from at least 83 mole % to 99.5 mole %, y ranges from at least 0.5 mole % to 13 mole %, and z ranges from at least 0.025 mole % to 4.25 mole %. In some embodiments, both R and R ₂ are independently alkyl groups and Ri is H, and n is at least 50 mole % and, in some embodiments, n is at least 75 mole %. When Ri is not the same as R ₂ , the polyalkylene ether functional group is a copolymer, and the copolymer can be a random copolymer, a block copolymer, or a segmented copolymer (including mixtures thereof). In some such embodiments, Ri is H, R ₂ is an alkyl group, and n is at least 50 mole %.

In some embodiments, packages of the present invention can provide improved release of complex fluids as discussed further herein.

These and other embodiments are described in more detail in the Detailed

Description.

Brief Description of Drawings

FIG. 1 shows an adjustable test platform for conducting fluid flow tests.

FIG. 2 shows a system for adjusting the angle of the test platform in FIG. 1.

FIG. 3 illustrates the placement of cat food on the adjustable test platform covered with a film at the outset of a fluid flow test.

Detailed Description

Unless specified otherwise herein, percentages are weight percentages (wt%) and temperatures are in °C.

The term "composition," as used herein, includes material(s) which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

The terms "comprising," "including," "having," and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term,

"consisting essentially of excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term "consisting of excludes any component, step or procedure not specifically delineated or listed. "Polymer" means a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term interpolymer as defined hereinafter. Trace amounts of impurities (for example, catalyst residues) may be incorporated into and/or within the polymer. A polymer may be a single polymer, a polymer blend or polymer mixture.

The term "interpolymer," as used herein, refers to polymers prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes copolymers (employed to refer to polymers prepared from two different types of monomers), and polymers prepared from more than two different types of monomers.

The terms "olefin-based polymer" or "polyolefin", as used herein, refer to a polymer that comprises, in polymerized form, a majority amount of olefin monomer, for example ethylene or propylene (based on the weight of the polymer), and optionally may comprise one or more comonomers.

The term, "ethylene-based polymer," as used herein, refers to a polymer that comprises, in polymerized form, a majority amount of ethylene monomer (based on the weight of the polymer), and optionally may comprise one or more comonomers.

The term, "ethylene/a-olefin interpolymer," as used herein, refers to an interpolymer that comprises, in polymerized form, a majority amount of ethylene monomer (based on the weight of the interpolymer), and an a-olefin.

The term, "ethylene/a-olefin copolymer," as used herein, refers to a copolymer that comprises, in polymerized form, a majority amount of ethylene monomer (based on the weight of the copolymer), and an a-olefin, as the only two monomer types.

"Polyethylene" or "ethylene-based polymer" shall mean polymers comprising greater than 50% by weight of units which have been derived from ethylene monomer. This includes polyethylene homopolymers or copolymers (meaning units derived from two or more comonomers). Common forms of polyethylene 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 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). These polyethylene materials are generally known in the art; however, the following descriptions may be helpful in understanding the differences between some of these different polyethylene resins.

The term "LDPE" may also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene" and is defined to mean that the polymer is partly or entirely homopolymerized or copolymerized in autoclave or tubular reactors at pressures above 14,500 psi (100 MPa) with the use of free-radical initiators, such as peroxides (see for example US 4,599,392, which is hereby incorporated by reference). LDPE resins typically have a density in the range of 0.916 to 0.935 g/cm ³ .

The term "LLDPE", includes both resin made using the traditional Ziegler-Natta catalyst systems as well as single-site catalysts, including, but not limited to, bis-metallocene catalysts (sometimes referred to as "m-LLDPE") and constrained geometry catalysts, and includes linear, substantially linear or heterogeneous polyethylene copolymers or

homopolymers. LLDPEs contain less long chain branching than LDPEs and includes the substantially linear ethylene polymers which are further defined in U.S. Patent 5,272,236, U.S. Patent 5,278,272, U.S. Patent 5,582,923 and US Patent 5,733,155; the homogeneously branched linear ethylene polymer compositions such as those in U.S. Patent No. 3,645,992; the heterogeneously branched ethylene polymers such as those prepared according to the process disclosed in U.S. Patent No. 4,076,698; and/or blends thereof (such as those disclosed in US 3,914,342 or US 5,854,045). The LLDPEs can be made via gas-phase, solution-phase or slurry polymerization or any combination thereof, using any type of reactor or reactor configuration known in the art.

The term "MDPE" refers to polyethylenes having densities from 0.926 to 0.935 g/cm ³ . "MDPE" is typically made using chromium or Ziegler-Natta catalysts or using single- site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts, and typically have a molecular weight distribution ("MWD") greater than 2.5.

The term "HDPE" refers to polyethylenes having densities greater than about 0.935 g/cm3, which are generally prepared with Ziegler-Natta catalysts, chrome catalysts or single- site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts.

The term "ULDPE" refers to polyethylenes having densities of 0.880 to 0.912 g/cm ³ , which are generally prepared with Ziegler-Natta catalysts, chrome catalysts, or single-site catalysts including, but not limited to, bis-metallocene catalysts and constrained geometry catalysts. The term "multilayer structure" refers to any structure comprising two or more layers having different compositions and includes, without limitation, multilayer films, multilayer sheets, laminated films, multilayer rigid containers, multilayer pipes, and multilayer coated substrates.

As used herein, the term "inner product facing surface" means the surface which is in contact with product in a package, when a monolayer structure or multilayer structure is formed into a package and filled with product.

Unless otherwise indicated herein, the following analytical methods are used in the describing aspects of the present invention:

Melt index: Melt indices I ₂ (or I ₂ ) and I ₁₀ (or I ₁₀ ) are measured in accordance to

ASTM D-1238 at 190° C and at 2.16 kg and 10 kg load, respectively. Their values are reported in g/10 min.

Density: Samples for density measurement are prepared according to ASTM D4703. Measurements are made, according to ASTM D792, Method B, within one hour of sample pressing.

The term molecular weight distribution or "MWD" is defined as the ratio of weight average molecular weight to number average molecular weight (M _w /M _n ). M _w and M _n are determined according to methods known in the art using conventional gel permeation chromatography (conventional GPC).

As used herein, the term "small scale root mean square roughness" refers to the root mean square roughness measured by atomic force microscopy using a sample size of 25 square microns. Samples are mounted onto a glass slide using double-sided tape. Four areas are analyzed on each sample. PeakForce tapping mode is obtained on a Dimension Icon (Bruker) using a Nanoscope V controller (software v 8.10b47). A ScanAsyst Air probe (Bruker Corporation) is used for all images (resonant frequency: 70 kHz; spring constant: 0.4 N/m). All images are obtained with a set point of 0.05 V and a peak force engage set point of 0.15 V. Images are collected over a 5 μηι x 5 μηι area with 1024 x 1024 resolution at a scan rate of 0.48 Hz. Images are post-processed using SPIP v.5.1.11 (Image Metrology). An average profile fit with a LMS Fit Degree of zero is applied to all images. Noise is removed with a Median_3x3_l_HighandLow_Circle filter. Surface roughness is averaged over four areas on each sample and reported for Sq (root mean square). The average value is reported.

As used herein, the term "large scale root mean square roughness" refers to the root mean square roughness measured using laser scanning microscopy on a sample size of 372240 square microns. All samples are analyzed as received over five areas. CLSM is obtained with a Keyence VK-9700 microscope (application viewer VK-H1 VIE) with a 20x objective lens and superfine resolution. All areas analyzed are 705 μηι x 528 μηι. All images are post-processed and analyzed using VK Analyzer Plus v.2.4.0.0 (Keyence).

Images are plane fit and flattened using a tilt correction function, and noise was removed by a normal height cut level filter. Surface roughness measurements are calculated across all height images for each sample and averaged together using SPIP v.5.1.11 (Image Metrology) and reported in Sq (root mean square). Prior to analysis, images are plane flattened with the z-offset mean set to zero.

Additional properties and test methods are described further herein.

The present invention relates generally to packages having improved product release properties. In some embodiments, the present invention advantageously incorporates certain resins in an inner surface of a package that results in the package exhibiting improved release of complex fluids such as personal care products (e.g., lotions, shampoos, body wash, etc.), consumer goods, food, pet food, and other products. Release of complex fluids can be considered in terms of efficient release and quick release. In general, an efficient release application is typically one where a product is used over a period of time and product is released from the package multiple times. Non-limiting examples of efficient release applications are packages for shampoo, body lotions, conditioners, and the like. A quick release application is typically one where the product is used a single time such that the product is released from the package once. Non-limiting examples of quick release applications include pet food, oils, salad dressing, liquid detergent pouches, and the like. While some embodiments of the packages of the present invention are better suited for efficient release applications, such embodiments, or other embodiments, may also be used in quick release applications.

Some embodiments of packages of the present invention are characterized based on their ability to release complex fluids. As used herein, a "complex fluid" is a fluid having a yield stress of at least 5 Pa and a viscosity of at least 10 Pa- s at a strain rate of 1 s ^"1 , when determined according to the following procedure: The yield stress of the fluid is determined using an MCR301 rheometer from Anton Paar GmbH (Austria). The instrument is equipped with stainless steel parallel plates of 50 mm diameter. The gap used is 400 or 500 μηι. Once loaded into the instrument, the sample is covered with a solvent trap to avoid loss of moisture. The temperature is controlled at 23 °C using Peltier heating elements. The sample is subjected to an upward stress ramp from 1 Pa to 100 Pa, followed by a downward stress ramp from 100 Pa to 1 Pa. The stress is increased and decreased linearly with a ramp rate of 100 Pa/min. A measurement is taken every 2 s. To quantify the value of the yield stress, a Herschel-Bulkley model is fitted with the data from the downward stress ramp using Rheoplus V3.61 software. The viscosity at 1 s ^"1 is determined from this data set.

Improved product release from packages can provide a number of advantages. With such improved release, a consumer or other user can remove and/or use more of the product that was originally provided in the package. To the extent residual product needs to be removed prior to recycling, some embodiments of the present invention can reduce recycling costs as less amount of residual product will need to be removed from the package. As another potential benefit, with some embodiments, a product manufacturer may have more formulation flexibility with its products (e.g., potential use of more viscous products or products with higher solids content).

Packages of the present invention generally include any type of container configured to hold complex fluids. Such packages are typically multilayer structures that can be prepared by blow molding, injection molding, compression molding, rotomolding, multilayer molding/extrusion processes, inject-over-inject molding processes, and others. Such packages can be in a variety of forms including, for example, bottles, pouches, cups, containers, and others from which a fluid can flow. Some particularly useful embodiments of the present invention are rigid packages.

An inner surface of the package is in contact with the complex fluid or other product in the package. When the package is a multilayer structure, the inner surface is part of an inner layer of the multilayer structure, again with the inner surface being in contact with the complex fluid or other product. In some embodiments, the package is a rigid package.

The package may comprise one embodiment as disclosed herein, or a combination of two or more embodiments.

In one embodiment, a package of the present invention comprises an inner surface comprising a polyalkylene ether modified polyolefin. The polyalkylene ether modified polyolefin, in some embodiments, comprises an imide moiety.

In some embodiments, the polyalkylene ether modified polyolefin is the reaction product of a maleated polyolefin (e.g., maleated polyethylene) and an amine terminated polyalkylene ether. In some such embodiments, the maleated polyolefin comprises a maleic anhydride grafted polyethylene. The polyethylene, in some such embodiments, comprises low density polyethylene or linear low density polyethylene. In some embodiments, the maleated polyolefin comprises a maleated polyolefin plastomer, such as a maleated polyethylene plastomer. In some embodiments, the maleated polyolefin comprises a copolymer comprising ethylene and maleic anhydride. In some embodiments where the maleated polyolefin comprises maleic anhydride, the maleated polyolefin comprises up to 10 weight percent maleic anhydride based on the weight of maleated polyolefin.

In some embodiments where the polyalkylene ether modified polyolefin is the reaction product of a maleated polyolefin (e.g., maleated polyethylene) and an amine terminated polyalkylene ether, the amine terminated polyalkylene ether comprises a monoamine terminated polyalkylene ether. In some such embodiments, the molecular weight of the amine terminated polyalkylene ether is between 250 and 15,000. In some such embodiments, the molar ratio of amine in the amine terminated polyalkylene ether to the maleic anhydride or maleic acid in the maleated polyolefin is 0.05 to 5.

In some embodiments, the polyalkylene ether modified polyolefin comprises the following compound:

where R, R _l5 R ₂ , R ₃ , and R4 independently comprise H or alkyl, where PO represents an olefin or alpha olefin monomer repeat unit, where x +y + z = 100 mole %, and where n + m = 100 mole %. In some embodiments, x ranges from at least 83 mole % to 99.5 mole %, y ranges from at least 0.5 mole % to 13 mole %, and z ranges from at least 0.025 mole % to 4.25 mole %. In other embodiments, x ranges from at least 86 mole % to 98 mole %. In other embodiments, x ranges from at least 87 mole % to 95 mole %. In some embodiments, when R4 is an alkyl group, y ranges from at least 0.5 mole % to 13 mole %. In other embodiments, when R4 is an alkyl group, y ranges from at least 2.5 mole% to 13 mole %. In some embodiments, when R4 is an alkyl group, y ranges from at least 5 mole% to 13 mole%. In other embodiments, z ranges from at least 0.070 mole % to 2.10 mole %. In some embodiments, z ranges from at least 0.070 mole % to 1.00 mole %. In other embodiments, z ranges from at least 0.14 mole % to 0.40 mole % .

In some embodiments, both R and R ₂ are independently alkyl groups and Ri is H, n is at least 50 mole % and in some embodiments, n is at least 75 mole %. When Ri is not the same as R ₂ , the polyalkylene ether functional group is a copolymer, and the copolymer can be either a random copolymer, a block copolymer, or a segmented copolymer (including mixtures thereof). In some such embodiments, Ri is H, R ₂ is an alkyl group, and n is at least 50 mole %. In some embodiments, R4 is -CH ₂ CH ₃ . In some embodiments, R4 is -CH.

2CH ₂ CH ₂ CH ₃ . In some embodiments, R4 is -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₃ .

In some embodiments, the polyalkylene ether modified polyolefin comprises the following compound:

where R, R _l5 R ₂ , and R ₃ independently comprise H or alkyl, where x' +y' = 100 mole %, and where n + m = 100 mole %. In some embodiments, both R and R ₂ are independently alkyl groups and Ri is H, n is at least 50 mole % and in some embodiments, n is at least 75 mole %. When Ri is not the same as R ₂ , the polyalkylene ether functional group is a copolymer, and the copolymer can be either a random copolymer, a block copolymer, or a segmented copolymer (including mixtures thereof). In some such embodiments, Ri is H, R ₂ is an alkyl group, and n is at least 50 mole %.

In some embodiments, the package comprises an interior volume, and further comprises a flowable product in the interior volume. In some embodiments, the flowable product is a liquid. The flowable product, in some embodiments, is a food product. In some embodiments, the flowable product is a body care product.

In some embodiments, a package of the present invention exhibits less product retention than a comparative package of the same size and shape when the comparative package does not include the inner surface. As noted above, packages of the present invention have an inner surface that includes a polyalkylene ether modified polyolefin. The polyolefin that is modified with polyalkylene ether can be polyethylene, polypropylene, or other poly-a-olefins. Such polyolefins can be hompolymers, random copolymers, or block copolymers in various embodiments.

In some embodiments, the polyolefin that is modified with polyalkylene ether is a maleated polyolefin. The polyolefin that is modified with polyalkylene ether is preferably a maleated polyethylene, but could also be, for example, maleated polypropylene. Such maleated polyolefins can be homopolymers, random copolymers, or block copolymers.

In some embodiments, the maleated polyolefin comprises maleic anhydride radically grafted on to the polyolefin. In some embodiments, the maleated polyolefin comprises maleic anhydride radically copolymerized with the polyolefin. The maleated polyolefins regardless of whether maleic anhydride is grafted on or copolymerized with the polyolefin, in some embodiments, comprise up to 10 weight percent maleic acid/maleic anhydride based on the total weight of the maleated polyolefin. In some embodiments, the maleated polyolefins comprise 0.1 to 10 weight percent maleic acid/maleic anhydride based on the total weight of the maleated polyolefin. All individual values and subranges from 0.1 to 10 percent by weight (wt%) are included herein and disclosed herein; for example the amount of the maleic acid/maleic anhydride can be from a lower limit of 0.1, 0.2, 0.3, 0.4, or 0.5 wt% to an upper limit of 2, 2.5, 3, 4, 5, 6, 7, 8, 9, or 10 wt% based on the total weight of the maleated polyolefin. For example, the amount of maleic acid/maleic anhydride is preferably from 0.2 to 5 wt%, or, more preferably, from 0.5 to 2.5 wt%.

When the maleated polyolefin is maleated polyethylene, the polyethylene can be a low density polyethylene (HDPE), a low density polyethylene (LDPE), a linear low density polyethylene (LLDPE), or a polyethylene plastomer. The maleated polyethylene is a maleated LDPE. In some embodiments, the maleated polyethylene is a maleated

polyethylene plastomer. In some embodiments, the maleated polyolefin comprises maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, or maleic anhydride grafted polyolefin plastomer. In some embodiments, the maleated polyolefin comprises maleic anhydride grafted low density polyethylene. In some embodiments, the maleated polyolefin comprises maleic anhydride grafted polyethylene plastomer.

Examples of commercially available maleated polyolefins that can be modified with polyalkylene ether include maleic anhydride grafted polyethylene commercially available from The Dow Chemical Company under the names AMPLIFY™ GR including, for example, AMPLIFY™ GR 202 and AMPLIFY™ GR 216; from DuPont under the name FUSABOND® including, for example, FUSABOND M series and FUSABOND® E series; from Addivant in its POLYBOND®3000 series; and from Mitsui Chemical America Inc. in its ADMERseries. Another example of a commercially available maleated polyolefins that can be modified with polyalkylene ether is Eastman G-3003 polymer, which is a maleic anhydride grafted polypropylene commercially available from Eastman Chemical Company.

As will be clear from further discussed further herein, when the polyolefin is modified with a polyalkylene ether, any functional groups on the polyolefin may also be modified. For example, with maleated polyolefins, such as maleic anhydride grafted polyethylene, the polyolefin may no longer have a maleic moiety once modified with the polyalkylene ether. The chemical structure of the polyalkylene ether modified polyolefin will thus depend on the particular reactants used.

In some embodiments, the polyalkylene ether modified polyolefin comprises an imide moiety. An imide moiety can result when, for example, a maleated polyolefin is reacted with an amine terminated polyalkylene ether. The following reaction scheme illustrates the formation of one embodiment of a polyalkylene ether modified polyolefin that is formed when a maleic anhydride grafted polyethylene is reacted with a primary, monoamine- terminated polyalkylene ether:

where R, R _l5 R ₂ , R ₃ , and R4 independently comprise H or alkyl, where PO represents an olefin or alpha olefin monomer repeat unit to which maleic anhydride had been grafted, where x +y + z = 100 mole %, and where n + m = 100 mole %. The reactivity of a primary amine with maleated olefin is fast and efficient with the anhydride being completely consumed and converted to an imide moiety as shown above.

As indicated in the above reaction scheme, in some embodiments, the polyalkylene ether modified polyolefin used to form packages of the present invention can be the reaction product of a maleated polyolefin with an amine-terminated polyalkylene ether. In such embodiments, the amine-terminated polyalkylene ether can be a homopolymer, a random copolymer, a block copolymer, or a segmented copolymer of hydrophilic polyalkylene oxides. Examples of such polyalkylene oxides can include polyethylene oxide, polyethylene glycol, or combinations thereof. Other examples of polyalkylene oxides that can be part of amine-terminated polyalkylene ethers include polypropylene oxide, polybutylene oxide, polytetramethylene oxide, as well as higher alkylene oxides, and combinations thereof. In some preferred embodiments, the majority (if not all) of the alkylene oxide in the amine- terminated polyalkylene ether is derived from or equivalent to ethylene oxide. In some embodiments, the amine-terminated polyalkylene ether is an ethylene oxide rich polyalkylene ether such that at least 50 mole % of the polyalkylene ether comprises ethylene oxide based repeat units/moieties. In some embodiments, the amine-terminated polyalkylene ether comprises at least 75 mole % ethylene oxide based repeat units/moieties. In some

embodiments, the amine-terminated polyalkylene ether is a propylene oxide rich

polyalkylene ether such that at least 50% of the polyalkylene ether comprises propylene oxide based repeat units/moieties. In some embodiments, the amine-terminated polyalkylene ether comprises at least 75 mole % propylene oxide based repeat units/moieties.

The amine terminated polyalkylene ether can be a monoamine terminated or polyamine terminated in various embodiments, but is preferably monoamine terminated.

Amine terminated polyalkylene ethers useful in forming some embodiments of polyalkylene ether modified polyolefins comprise the structure:

RO (CH ₂ CHO) _n (CH ₂ CHO) _m — CH ₂ CHNH ₂

Ri f¾ R3

wherein R, R _{l 5} R2, and R ₃ independently comprise H or an alkyl group and wherein n + m = 100 mole %. In some preferred embodiments of the above monoamine terminated polyalkylene ether, both R and R ₂ are independently alkyl groups and Ri is H, and n is at least 50 mole %, and more preferably at least 75 mole %. In some embodiments when Ri is not the same as R ₂ , the polyalkylene ether is a copolymer and the copolymer can be either a random copolymer, a block copolymer, or a segmented copolymer (including their mixtures). In some such embodiments of the above monoamine terminated polyalkylene ether, Ri is H, R ₂ is an alkyl group, and n is at least 50 mole %.

The molecular weight (M _n ) of the amine-terminated polyalkylene ether can range from 250 to 15,000. Preferably, the molecular weight (M _n ) of the amine-terminated polyalkylene ether is from 400 to 10,000, more preferably, from about 600 to 5,000, and most preferably from about 750 to 3,000.

In embodiments where an amine terminated polyalkylene ether is reacted with a maleated polyolefin, the molar ratio of amine in the amine terminated polyalkylene ether to the maleic anhydride/maleic acid on/in the polyolefin can range from 0.05 to 5. All individual values and subranges from 0.05 to 5 are included herein and disclosed herein; for example, the molar ratio of amine to maleic anhydride/maleic acid can be from a lower limit of 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5 to an upper limit of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5. For example, the molar ratio of amine to maleic anhydride/maleic acid is preferably from 0.2 to 2.5, or, more preferably, from 0.5 to 1.5. In some embodiments, the molar ratio of amine to maleic anhydride/maleic acid is less than or equal to 1.0.

Examples of commercially available amine terminated polyalkylene ethers that can be reacted with maleated polyolefins to provide polyalkylene ether modified polyolefins for use in some embodiments of packages of the present invention include primary, monoamine- terminated polyalkylene ethers commercially available from Huntsman Corporation as part of its JEFF AMINE M series such as the following:

As set forth in the examples, polyalkylene ether modified polyalkylene for use in some embodiments of the present invention can be prepared by both solution and melt processes. For example, temperatures for melt reacting maleated polyolefins (e.g., maleic anhydride grafted polyolefin) with amine-terminated polyalkylene ethers range from just above the melting point of the polyolefin to just below its degradation temperature— e.g., from 140° C to 300° C, preferably from 160° C to 260° C, and more preferably from 180° C to 240° C. In connection with the solution reaction of maleated polyolefins (e.g., maleic anhydride grafted polyolefin) with amine-terminated polyalkylene ethers, any solvent can be used that sufficiently dissolves each component for reaction and dissolution to occur.

Examples of preferred solvents include toluene and xylene isomers with reaction

temperatures ranging from 60° C to the boiling point of the solvent.

Examples of polyalkylene ether modified polyolefins that can be used to form packages according to some embodiments of the present invention include: where x +y + z = 100 weight mole %. The above structure illustrates an embodiment where a linear low density polyethylene (utilizing octene as a comonomer) is radically grafted with maleic anhydride, and then reacted with a polyalklylene ether amine.

Other examples of polyalkylene ether modified polyolefins that can be used to form packages according to some embodiments of the present invention include:

This structure illustrates an embodiment where a low density polyethylene (LDPE) is radically grafted with maleic anhydride and then reacted with a polyalkylene ether amine. In this structure, butyl and ethyl branches are shown on the LDPE backbone for exemplary purposes, and persons of skill in the art will recognize that a variety of alkyl branches can be part of a typical LDPE structure. Further, the total amount of monomer units in this structure equal 100 mole %, and none of the repeat units would be zero mole % (i.e., at least some amount of each unit is present), in one embodiment.

The polyalkylene ether modified polyolefins disclosed herein can form at least part of an inner surface of a package according to embodiments of the present invention. In some embodiments, the package is a multilayer structure and the polyalkylene ether modified polyolefin is incorporated at least into the inner layer (i.e., the layer that would contact the product to be contained in the package).

In some embodiments, the inner layer of the package comprises up to 100% by weight polyalkylene ether modified polyolefin based on the weight of the inner layer. The inner layer, in some embodiments comprises at least 30% by weight polyalkylene ether modified polyolefin based on the weight of the inner layer. All individual values and subranges from 30 percent to 100 percent by weight (wt%) are included herein and disclosed herein; for example the amount of the polyalkylene ether modified polyolefin can be from a lower limit of 30, 35, 40, 45, or 50 wt% to an upper limit of 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 wt% based on the total weight of the inner layer. For example, the amount of polyalkylene ether modified polyolefin can be from 50 to 90 wt% in some embodiments.

In some embodiments, the polyalkylene ether modified polyolefin can be blended in the inner layer with an ethylene-based polymer. In such embodiments, the inner layer comprises at least 5% by weight ethylene-based polymer and up to 70% by weight ethylene- based polymer based on the weight of the inner layer. All individual values and subranges from 5 to 70 percent by weight (wt%) are included herein and disclosed herein; for example the amount of the ethylene-based polymer can be from a lower limit of 5, 10, 15, 20, or 25 wt% to an upper limit of 30, 35, 40, 45, 50, 55, 60, 65, or 70 wt% based on the total weight of the inner layer. For example, the amount of ethylene-based polymer can be from 10 to 50 wt% in some embodiments. Exemplary ethylene-based polymers for use in the inner product facing layer include DOWLEX, ELITE and ENGAGE, all of which are commercially available from The Dow Chemical Company (Midland, ML USA) and EXCEED, which is commercially available from ExxonMobil Chemical Corporation (Baytown, TX, USA).

In some embodiments, the inner layer comprises one or more low density

polyethylene polymers (LLDPE or LDPE or VLDPE). In some embodiments, when the polyalkylene ether modified polyolefin is formed from the reaction of an amine-terminated polyalkylene ether and a maleated LLDPE, the inner layer can further comprise an LLDPE. Any LLDPE, such as described in U.S. Patents 5,272,236 and 5,278,272, the disclosures of which are incorporated herein by reference, may be used in such embodiments.

It should be understood that the inner layer can further comprise one or more additives as known to those of skill in the art such as, for example, antioxidants, ultraviolet light stabilizers, thermal stabilizers, slip agents, antiblock, pigments or colorants, processing aids, crosslinking catalysts, flame retardants, fillers and foaming agents. While packages of the present invention comprise an inner surface comprising polyalkylene ether modified polyolefin, it should be understood that the remainder of the package can be formed using techniques known to those of skill in the art based on the desired size of the package, the desired shape of the package, the manufacturing technique used to form the package, compatibility with an inner surface or inner layer comprising functionalized polyolefin, the desired properties of the package, the product to be contained in the package, and other factors.

According to embodiments of packages wherein the package comprises a multilayer structure, the thickness of the inner layer comprising polyalkylene ether oxide can be from 5 to 50% of the total thickness of the multilayer structure. All individual values and subranges from 5 to 50 % are included and disclosed herein; for example the thickness of the inner layer facing layer can range from a lower limit of 5, 15, 30, or 45 % of the total thickness of multilayer structure to an upper limit of 10, 20, 35 or 50 % of the total thickness of multilayer structure. For example, the thickness of the inner layer may be from 5 to 50% of the total multilayer structure thickness, or in the alternative, from 5 to 30%, or in the alternative, from 25 to 50%, or in the alternative, from 15 to 45%. The percentage thickness of the package contributed by the inner layer is a function of, inter alia, the intended use of the package and the product to be contained.

In some embodiments, the inner product facing surface has a small scale root mean square roughness of equal to or less than 40 nm. All individual values and subranges from equal to or less than 40 nm are included and disclosed herein. For example, the small scale root mean square roughness can be equal to or less than 40 nm, or in the alternative, equal to or less than 35 nm, or in the alternative, equal to or less than 30 nm, or in the alternative, equal to or less than 25 nm. In a particular embodiment, the small scale root mean square roughness is equal to or greater than 1 nm. All individual values and subranges from equal to or greater than 1 nm are included and disclosed herein. For example, the small scale root mean square roughness may be equal to or greater than 1 nm, or in the alternative, equal to or greater than 5 nm, or in the alternative, equal to or greater than 10 nm, or in the alternative, equal to or greater than 15 nm.

In certain embodiments, the inner product facing surface has a large scale root mean square roughness of equal to or less than 500 nm. All individual values and subranges of equal to or less than 500 nm are included and disclosed herein. For example, the large scale root mean square roughness of the inner product facing layer can be equal to less than 500 nm, or in the alternative, equal to less than 450 nm, or in the alternative, equal to less than 400 nm, or in the alternative, equal to less than 350 nm.

Packages of the present invention generally include any type of container configured to hold complex fluids. Such packages are typically multilayer structures that can be prepared by blow molding (e.g., continuous blow molding, reciprocating blow molding, accumulator blow molding, sequential blow molding, injection blow molding, stretch blow molding), injection molding, compression molding, rotomolding, multilayer

molding/extrusion processes, inject-over-inject molding processes, coextrusion,

thermoforming, lamination, and others.

Packages of the present invention can be used to contain a variety of products. In particular, packages of the present invention are particularly well-suited for containing complex fluids for which improved release from the package is desired. As noted above, a "complex fluid" is a fluid having a yield stress of at least 5 Pa and a viscosity of at least 10 Pa s at a strain rate of 1 s ^"1 , when measured using the procedure described above. Examples of such complex fluids include, without limitation, personal care products (e.g., lotions, shampoos, body wash, etc.), consumer goods, food (e.g., salad dressing), pet food (e.g., soft dog or cat food), and other products.

In some embodiments, packages of the present invention exhibit less product retention than a comparative package of the same size and shape when the comparative package does not include polyalkylene ether modified polyolefin on its inner surface. In other words, product within packages according to some embodiments of the present invention can more readily release from the inner surface (and thus, the package itself) than from comparative package.

Some embodiments of the invention will now be described in detail in the following Examples.

Examples

Example 1

Melt Extrusion Synthesis of Polvalklylene Ether Modified Polyolefin:

A polyalkylene ether modified polyolefin is formed using melt extrusion as follows. A Krupp Werner & Pfleiderer twin-screw co-rating extruder system (ZSK-25) is used. The system includes an extruder with 12 barrel sections, 11 of which are independently controlled with electric heating and water cooling, a loss-in weight feeder (K-Tron, model KCLQX3), a heat traced gear pump system to inject amino-terminated poly(ethylene oxide-co-propylene oxide) liquid, and a Gala LPU underwater pelletizer. The length to diameter ratio of the extruder is 48.

The K-Tron feeder feeds maleic anhydride grafted polyethylene plastomer pellets (density = 0.875 g cm ³ ; I ₂ = 1.3 g/10 minutes; 0.79 weight percent maleic anhydride graft level) under a nitrogen purge into the extruder feed throat (Barrel #1). A gear pump injects preheated amino-terminated poly(ethylene oxide-co-propylene oxide) (Jeffamine M-1000 from Huntsman Corporation) liquid into the 4th barrel section (Zone #3 in Table 1) of the extruder. Table 1 summarizes other process parameters associated with a typical extrusion to produce the polyalkylene ether modified polyolefin.

Table 1

The resulting modified polymer (polyalkylene ether modified polyolefin) is pumped by the extruder through a two-hole die into the cutting chamber of the Gala LPU underwater pelletizer. The cutting speed ranges from 2800 to 3300 rpm depending on the pellet size desired. In addition, the water temperature of the pelletizing system is 4.4° C. The total feed rate (6.80 kg/h) and screw speed (500 rpm) is held constant for all samples. The extruder torque load varies from 60-78 %. The polyalkylene ether modified polyolefin pellets are used to produce coextruded blow molded bottles as described below.

Coextruded blow molded bottles are produced on a BEKUM BM-502S commercial blow molding line. A BEKUM BM-502S unit is used to coextrude a three-layer A/B/C blow molded structure (A= inner product facing layer, B= core layer and C= outer layer). The BM-502S is composed of two 38 mm diameter single-screw extruders for outer and inner skin materials and one 60 mm diameter single-screw extruder for a core layer. It has a multi- manifold coextrusion blow molding head where individual layers are formed separately and merged together before the exit of annular die. Materials are extruded at 6.8 kg/h at 188 °C into a tubular parison through a converging die tool with an annular opening between a die bushing, 0 17.8 mm x 20° and a die pin (0 14.0 mm x 15°). Extruded parisons are blow molded with pressurized air at 4.1 bar for 13 s into 0.89 mm thick wall, 19.9 cm tall, 0 5.9 cm, 414 ml Boston Round bottles. Core Layer B and outer Layer C are kept constant and are formed from a bimodal high density polyethylene having a density of 0.958 g/cm ³ and a melt index (I ₂ ) of 0.28 g/10 min at 190 °C/2.16 kg.

The inner product facing layer is Layer A and has a thickness that is 10% of the total thickness of the wall (Layers B and C combine to provide the remaining 90% of the wall thickness). In Comparative Bottle A, the inner product facing layer (Layer A) is formed from the same resin as Layers B and C. In Inventive Bottle 1, the inner product facing layer (Layer A) is formed from the pellets of polyalkylene ether modified polyolefin that were prepared as described above.

The Bottles are evaluated for product release performance using the following protocol:

1) Weigh the empty bottle without cap to get a tare weight.

2) Fill the blow molded bottle to -70% of its volume capacity with body wash. The body wash has a viscosity of 72 Pa s at a strain rate of 1 s ^"1 , when measured using the procedure described above. The body wash has a yield stress of 39 Pa.

3) Cap the bottle tightly.

4) Invert the bottle and rest it on its cap. (Time (t) = 0)

5) Record the time and wait 24 +/- 1 hour.

6) At 24 +/- 1 hour, take the cap off the bottle and squeeze it until 50% of product is dispensed. Record the weight of the bottle + remaining body wash at this point. (t=24h)

7) Recap the bottle and place it in the inverted position for 4 hours.

8) At 4 hours after half emptying (t=28h), again uncap the bottle. Squeeze, but do not shake, the bottle repeatedly until 3 successive squeezes do not remove any material. Record the weight of the bottle + remaining body wash again.

9) Recap and allow the bottle to sit for an additional 20 hours in the inverted position, for a total of 24 hours since the first emptying, and 48 hours since filling.

10) At 24 hours after the first emptying, shake the bottle and squeeze it to remove as much remaining material as possible. Alternate between three shakes and a squeeze. Repeat this cycle until 3 successive shakes and a squeeze do not remove any body wash. (t=48h)

11) Record the final weight of the bottle + body wash. (t=48h)

5 replicates of each Bottle are measured. The results are shown in Table 2:

Table 2

The data demonstrate that Inventive Bottle 1 exhibits -50% of the product retention exhibited by Comparative Bottle A.

Example 2

Solution Based Synthesis of Polvalkylene Ether Modified Polyolefin:

50.0 grams of maleic anhydride grafted low density polyethylene pellets (density = 0.930 g/cm ³ ; I ₂ = 8.0 g/10 minutes; 0.89 weight percent maleic anhydride graft level) are dissolved in 495 mL of xylenes in a 3 neck 500 mL flask at 85° C. After the pellets dissolve in the xylenes to form a homogeneous solution, 4.60 mL of amino-terminated poly(ethylene oxide-co-propylene oxide) (Jeffamine M-1000 from Huntsman Corporation) is added to the solution and reacted for 18 hours. The reaction is monitored by infrared spectroscopy. When the shift of the COOH peak (1715 cm ^"1 ) to maleimide (1724 cm ^"1 ) is observed, the product is retrieved from solution by precipitation from acetone (3:1 ratio of acetone to xylenes) and vacuum filtration. After drying the product in vacuo at 40° C overnight, the product is redissolved in xylenes (500 mL) at 100° C, re-precipitated from acetone (2 L), and filtered. The product is then dried in vacuo at 40° C again and pressed into films (140° C) between Mylar sheets on a carver press at 1034 bar. The films are soxhleted in chloroform overnight to remove trace amounts of unreacted amino terminated polyethylene glycol and dried in vacuo at 40° C in a vacuum oven until a constant weight is obtained. Finally, several films are prepared for analysis by compression molding on a Tetrahedron press. These films are referred to as Inventive Film 1.

49.9 grams of maleic anhydride grafted polyethylene plastomer pellets (density = 0.875 g/cm ³ ; I ₂ = 1.3 g/10 minutes; 0.79 weight percent maleic anhydride graft level) are dissolved in 490 mL of xylenes in a 3 neck 1 L flask at 85° C. After the pellets dissolve in the xylenes to form a homogeneous solution, 4.15 mL of amino-terminated poly(ethylene oxide-co-propylene oxide) (Jeffamine M-1000 from Huntsman Corporation) is added to the solution and reacted for 18 hours. The reaction is monitored by infrared spectroscopy. When the shift of the COOH peak (1712 cm ^"1 ) to maleimide (1701cm ¹ ) is observed, the product is retrieved from solution by precipitation from acetone (3:1 ratio of acetone to xylenes) and vacuum filtration. After drying the product in vacuo at 40° C overnight, the product is re- dissolved in xylenes (500 mL) at 100° C, re-precipitated from acetone (2L), and filtered. The product is then dried in vacuo at 40° C again and pressed into films (140° C) between Mylar sheets on a carver press at 1034 bar. The films are soxhleted in chloroform overnight to remove trace amounts of unreacted amino terminated polyethylene glycol and dried in vacuo at 40° C in a vacuum oven until a constant weight is obtained. Finally, several films are prepared for analysis by compression molding on a Tetrahedron press. These films are referred to as Inventive Film 2.

A clamp hot press with controllable temperature ramp and internal timing with water cooling control is used for melting and compressing films. Mylar sheets are cut to 25 cm x 25 cm and placed over and under the chase (dimensions 10 cm x 10 cm x 0.013 mm).

Underneath and overtop of the Mylar, sheets of DuoFoil were used to negate imperfections permeating from the plates of the press. Polymer product is placed in the center of the chase, covered with Mylar and DuoFoil, and placed in the preheated press set to 145° C with no pressure applied for 3 minutes. A force of 2721 kg is applied and held for 1 minute. Then, a larger force (13,608 kg) is applied and held for 5 minutes at 145° C. After 5 minutes under high force, a cooling cycle is initiated (cooling rate of 60° C/min) with the 13,608 kg force applied. Cooling is applied until the plates reach 40° C. The press then automatically disengages the force, and the clamps open. Films are removed from the press and cooled to ambient temperature for 3 minutes before removal from the Mylar and DuoFoil sandwiched setup. The films are stored in aluminum foil until analysis.

Example 3

Product Evacuation (Flow Test):

An adjustable incline plane is designed to perform complex fluid flow tests as shown in FIG. 1. A solid frame of aluminum channel is used to mount a camera with the focal plane parallel to a test platform in order to video capture complex fluid flow. A Wixey digital inclinometer accurate to 0.1° is used to ensure the angle of the test platform is correct. An air cylinder driven system is adapted to gradually change the angle of incline of the test platform. The system consists of a pressure regulated air supply, a needle valve to control flow of air into the cylinder, a double acting air cylinder, and a control valve as shown in FIG. 2. The adjustable angle of the test platform is designed to simulate the emptying of a flexible pouch containing a product.

In this example, the flow of cat food (chicken chunks in gravy) on a surface (6.35 cm x 10.16 cm) is evaluated as follows:

1. 5 grams of cat food (from a master batch to eliminate product variability) is dispensed on a film on the test platform in the flat position (0° incline, horizontal position). The cat food is dispensed on one end of the test platform so that the cat food slides down about 7.62 cm along the long axis (see FIG. 3). The starting position of the cat food on the test surface is monitored to make sure that the cat food slides through the same distance before falling off the test surface.

2. The air cylinder system is used to gradually change the angle of inclination from 0° (horizontal orientation) to 90° (vertical orientation) in ~5 seconds.

3. The test platform rests at 90° (vertical orientation) for 10 seconds.

4. The test platform is returned to 0° (horizontal orientation) from 90° (vertical orientation) in ~5 seconds.

5. The weight of the cat food retained on the film surface is measured. A film that retains less cat food than a comparative film can be said to exhibit better product release (or less product retention).

Three films are evaluated for cat food retention. Comparative Film A is formed from the maleic anhydride grafted low density polyethylene pellets (density = 0.930 g cm ³ ; I ₂ = 8.0 g/10 minutes; 0.89 weight percent maleic anhydride graft level) that were used to form Inventive Film 1, except the maleic anhydride grafted low density polyethylene is not reacted with amino-terminated polyethylene glycol. Comparative Film B is a commercially available laminate having an inner surface that does not include polyalkylene ether modified polyolefin. The third film is Inventive Film 1. Each film is measured for cat food retention 3times, and the average values are determined. The results are summarized in Table 3:

Table 3

Inventive Film 1 is statistically different from Comparative Film A and Comparative Film B, and shows a substantial reduction in cat food retention. Inventive Film 1 comprises an inner surface having a polyalkylene ether modified polyolefin, whereas Comparative Films A and B do not. These results are surprising and indicate that polyalkylene ether functionalization of the polyolefin reduces the interaction between the cat food and the polyolefin surface. Example 4

Two additional films are evaluated for cat food retention using the Product

Evacuation (Flow Test) described above. Comparative Film C is formed from the maleic anhydride grafted polyethylene plastomer pellets (density = 0.875 g/cm ³ ; I ₂ = 1.3 g/10 minutes; 0.79 weight percent maleic anhydride graft level) that were used to form Inventive Film 2, except the maleic anhydride grafted polyethylene plastomer is not reacted with amino-terminated polyethylene glycol. The third film is Inventive Film 2. Each film is measured for cat food retention 3 times, and the average values are determined. The results (along with the prior results for Comparative Film B from Example 2) are summarized in

Table 4:

Table 4 Inventive Film 2 is statistically different from Comparative Film B and Comparative Film C, and shows a substantial reduction in cat food retention. Inventive Film 2 comprises an inner surface having a polyalkylene ether modified polyolefin, whereas Comparative Films B and C do not. These results are surprising and indicate that polyalkylene ether functionalization of the polyolefin reduces the interaction between the cat food and the polyolefin surface. Example 5

In this example, four compression molded plaques are evaluated for product retention in connection with a personal care product (body wash).

The plaques are prepared by compression molding pellets as follows. The frames (chases) used are either 20.32 cm x 25.4 cm x 0.051 cm or 15.24 cm x 20.32 cm x 0.064 cm. Polyethylene terephthalate film having a thickness of 0.051 cm and a width of 20.32 cm is used as a release film. It is backed with a disposable aluminum slip sheet that is in turn backed with a 0.3175 cm thick steel plate. This configuration resulted in smooth surface finish of the plagues while providing rigid backing. Comparative Plaque A is compression molded at 190° C, while each of the other plaques are compression molded at 210° C. The molding cycle for each of the plaques is as follows: (a) 7 minute hold time at low pressure (-0.34 bar for an 20.32 cm x 25.4 cm frame); (b) 5 minute hold time at high pressure (-13.1 bar for an 20.32 cm x 25.4 cm frame); and (c) Hold at high pressure and cool using water jacketed mold platens. Cooling takes -10 minutes to reach 30° C from a starting temperature of -200° C. The plaque is then de-molded, and allowed to sit for -24 hours at room temperature/humidity before testing.

Comparative Plaque A is formed from pellets of a non-functionalized random polyethylene copolymer having a density of 0.87 g/cm ³ and a melt index (I ₂ ) of 5 g/10 minutes. Comparative Plaque B is formed from maleic anhydride grafted polyethylene plastomer pellets (density = 0.875 g/cm ³ ; I ₂ = 1.3 g/10 minutes; 0.79 weight percent maleic anhydride graft level). Comparative Plaque C is formed from pellets of a high density polyethylene (density = 0.958 g/cm ³ ; I ₂ = 0.28 g/10 minutes). Inventive Plaque 1 is formed from the same polymer used to form Inventive Film 2 above.

In this example, the flow of body wash on a surface (2.5 inches x 4 inches) is evaluated as follows:

1. 5 grams of body wash (from a master batch to eliminate product variability) is dispensed on a plaque on the test platform (same test platform as used in connection with

Examples 2 and 3) in the flat position (0° incline, horizontal position). The body wash is dispensed on one end of the test platform.

2. The air cylinder system is used to gradually change the angle of inclination from 0° (horizontal orientation) to 70°. The body wash begins to start sliding down the surface.

3. After the front end of the body wash slips off the edge of the test platform, the angle of inclination is changed from 70° to 90°. At this point of the test, a thin film of the body wash is usually observed.

4. The 90° (vertical orientation) is maintained for one hour. Weight measurements are made to calculate the amount of body wash (%) retained on the test surface.

Each plaque is measured for body wash retention 3 times, and the average values are determined. The results are summarized in Table 5:

Table 5

The body wash retention results indicate that Inventive Plaque 1 comprising an inner surface with a polyalkylene ether modified polyolefin reduces product retention with respect to the non-functionalized alpha olefin random copolymer (Comparative Plaque A). Inventive Plaque 1 also exhibits significantly lower weight retention with respect to the Comparative Plaques B and C (-80% improvement). These results suggest that polyolefins can be modified with polyalkylene ethers to reduce product weight retention and can be used as inner layers in packages to improve product release.