EP4615913A1

EP4615913A1 - Polymer blend and packaging article formed from the blend

Info

Publication number: EP4615913A1
Application number: EP23838317.8A
Authority: EP
Inventors: Jun Wang; Mona Alinejad; Hope TOWNSEND; Kenneth REED III
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 2022-12-15
Filing date: 2023-12-11
Publication date: 2025-09-17
Also published as: WO2024129583A1; CN120322505A; AU2023396788A1; MX2025006759A

Abstract

Polymer blends and packaging articles produced via extrusion blow molding using the polymer blends are described. The polymer blends may include cyclic olefin copolymer and high-density polyethylene. The polymer blends may be substantially homogeneous. Reduced wall thicknesses and/or comparable or improved mechanical properties of the packaging articles made from the polymer blends may be achieved when compared to packaging articles made from high-density polyethylene only.

Description

POLYMER BLEND AND PACKAGING ARTICLE FORMED FROM THE BLEND

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority from U.S. Provisional Application No. 63/387,526, filed December 15, 2022, the contents of which are hereby incorporated herein by reference in their entirety.

BACKGROUND

[0002] Plastic materials arc widely used in packaging applications. Due to environmental sustainability considerations, reduced plastic usage in production of packaging articles is desired, which can be achieved in part by reducing the wall thickness of the package articles. However, reduced wall thickness can lead to reduced mechanical strengths, limiting the utility of such thinwalled packaging articles. Thus, a need exists for packaging articles that use less plastic while still exhibiting satisfactory mechanical strengths.

BRIEF SUMMARY

[0003] According to some embodiments, a packaging article may be produced via extrusion blow molding using a polymer blend. In some embodiments, the polymer blend may include cyclic olefin copolymer and high-density polyethylene. In some embodiments, the polymer blend may be substantially homogeneous. In some embodiments, the cyclic olefin copolymer may be present in the polymer blend in an amount greater than 8 wt. %.

[0004] According to some embodiments, a packaging article may be produced via extrusion blow molding using a polymer blend. In some embodiments, the polymer blend may include cyclic olefin copolymer and high-density polyethylene. In some embodiments, the polymer blend may be substantially homogeneous. In some embodiments, the cyclic olefin copolymer may be present in the polymer blend in an amount ranging from about 5 wt. % to about 20 wt. %. In some embodiments, the packaging article produced via extrusion blow molding may include an interior surface and an exterior surface collectively defining a wall thickness of the packaging article. In some embodiments, the wall thickness of the packaging article may be about 2 mm or less. [0005] In some embodiments, a method of producing a packaging article may include providing a polymer blend and forming the packaging article from the polymer blend via extrusion blow molding. In some embodiments, the polymer blend may include cyclic olefin copolymer and high- density polyethylene. In some embodiments, the polymer blend may be substantially homogeneous. In some embodiments, the cyclic olefin copolymer may be present in the polymer blend in an amount ranging from about 5 wt. % to about 20 wt. %. In some embodiments, the packaging article formed via extrusion blow molding may include an interior surface and an exterior surface collectively defining a wall thickness of the packaging article. In some embodiments, the wall thickness of the packaging article may be about 2 mm or less.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 schematically illustrates a packaging article according to some embodiments.

[0007] FIGS. 2A-2F schematically illustrate an extrusion blow molding process for producing a packaging article according to some embodiments.

[0008] FIG. 3 shows mechanical properties, in particular, Young’s modulus and elongation at break, of various specimens.

[0009] FIGS. 4A-4B are scanning electron microscope (SEM) images showing the morphology of various specimens.

[0010] FIGS. 5A-5C are atomic force microscope (AFM) images showing the morphology of various specimens.

[0011] FIG. 6 shows force at yield in top load tests and major wall load tests of various packaging articles.

[0012] FIG. 7 shows wall thicknesses in various portions of packaging articles.

[0013] FIG. 8 shows material properties of various specimens.

[0014] FIG. 9 shows material properties of various specimens.

[0015] FIGS. 10A-10G are atomic force microscope (AFM) images showing the morphology of various specimens.

[0016] FIG. 11 shows wall thicknesses in various portions of packaging articles.

[0017] FIG. 12 shows wall thicknesses in various portions of packaging articles.

[0018] FIG. 13 shows wall thicknesses in various portions of packaging articles.

[0019] FIG. 14 shows material properties of various specimens. [0020] FIGS. 15A-15D are atomic force microscope (AFM) images showing the morphology of various specimens.

[0021] FIGS. 16A-16D are atomic force microscope (AFM) images showing the morphology of various specimens.

[0022] FIGS. 17A-17D are scanning electron microscope (SEM) images showing the morphology of various specimens.

[0023] FIGS. 18A-18D are scanning electron microscope (SEM) images showing the morphology of various specimens.

DETAILED DESCRIPTION

[0024] For illustrative purposes, the principles of the present invention are described by referencing various exemplary embodiments thereof. Although certain embodiments of the invention are specifically described herein, one of ordinary skill in the art will readily recognize that the same principles are equally applicable to, and can be employed in other apparatuses and methods. Before explaining the disclosed embodiments of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of any particular embodiment shown. The terminology used herein is for the purpose of description and not of limitation.

[0025] The description of illustrative embodiments according to principles of the present invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description of embodiments of the invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top,” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms arc for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation unless explicitly indicated as such. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto.

[0026] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context dictates otherwise. The singular form of any class of the ingredients refers not only to one chemical species within that class, but also to a mixture of those chemical species. The terms “a” (or “an”), “one or more” and “at least one” may be used interchangeably herein. The terms “comprising”, “including”, and “having” may be used interchangeably. The term “include” should be interpreted as “include, but are not limited to”. The term “including” should be interpreted as “including, but are not limited to”.

[0027] As used throughout, ranges are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. Thus, a range from 1-5, includes specifically 1, 2, 3, 4 and 5, as well as sub ranges such as 2-5, 3-5, 2-3, 2-4, 1-4, etc.

[0028] The term “about” when referring to a number means any number within a range of 5% of the number. For example, the phrase “about 2.0 wt. %” refers to a number between and including 1.900 wt. % and 2.100 wt. %.

[0029] All references cited herein are hereby incorporated by reference in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls.

[0030] The abbreviations and symbols as used herein, unless indicated otherwise, take their ordinary meaning. The abbreviation “wt. %” means percent by weight. The symbol “°” refers to a degree, such as a temperature degree or a degree of an angle. The symbols “h”, “min”, “mL”,” nm”, “pm” means hour, minute, milliliter, nanometer, and micrometer, respectively.

[0031] Any member in a list of species that are used to exemplify or define a genus, may be mutually different from, or overlapping with, or a subset of, or equivalent to, or nearly the same as, or identical to, any other member of the list of species. Further, unless explicitly stated, such as when reciting a Markush group, the list of species that define or exemplify the genus is open, and it is given that other species may exist that define or exemplify the genus just as well as, or better than, any other species listed.

[0032] FIG. 1 schematically illustrates a packaging article 100 according to some embodiments. The packaging article 100 may include a body 102. The packaging article 100 may be configured for receiving in the body 102 a substance and for dispensing therefrom the substance. In some embodiments, the packaging article 100 may further include a closure component (not shown) that can be detachably coupled to the body 102. Although a bottle is shown in FIG. 1, the packaging article 100 or the body 102 may take any suitable form, such as a tube, a box, a can, etc., so long as it can be configured for receiving or storing therein a substance and for subseqently dispensing the substance.

[0033] The body 102 may include a first end or a top end 104 and a second end or a bottom end 106. The top end 104 may define an opening for filling the body 102 with a substance and for dispensing therefrom the substance. The bottom end 106 may form a base for supporting the packaging article 100 on a platform. A longitudinal axis of the body 102 may extend between the top end 104 and the bottom end 106.

[0034] In some embodiments, the body 102 may be axially symmetrical around the longitudinal axis. In some embodiments, the body 102 may not be axially symmetrical around the longitudinal axis. In some embodiments, the body 102 may include a width dimension (perpendicular to the longitudinal axis) different from a depth dimension (perpendicular to the longitudinal axis and the width dimension). The body 102 may include a first major wall 112, a second major wall opposite the first major wall 112, and opposite first and second side walls 116, 118 extending between the first major wall 112 and the second major wall. In some embodiments, the body 102 may further include shoulders 120, 122 defining transitions from the side walls 116, 118 to a neck 124 of the body 102. The transitions between the side walls 116, 118 and the bottom end 106 of the body 102 may define bottom comers 126, 128 of the body 102. A width of the body 102 may be defined by a distance between the side walls 116, 118. A depth of the body 102 may be defined by a distance between the first major wall 112 and the second major wall.

[0035] In some embodiments, the major walls 112 and/or side walls 116, 118 may be substantially planar or flat. In some embodiments, the major walls 112 and/or side walls 116, 118 may be contoured. In some embodiments, the transitions between the major walls 112 and the side walls 116, 118 may form comers of the body 102. In some embodiments, the transitions between the major walls 112 and/or the side walls 116, 118 may be continuous. Tn some embodiments, the body 102 may have a consistent width and/or a consistent depth. In some embodiments, the body 102 may have a varying width and/or a varying depth. In some embodiments, the width of the body 102 may be generally greater than the depth of the body 102, and a curvature defined by the first major wall 112 and/or the second major wall may be less than a curvature defined by the side walls 116, 118.

[0036] The body 102 may include an interior surface and an exterior surface. The exterior surface of the body 102 may be collectively defined by the exterior surfaces of the first major wall 112, the second major wall, the side walls 116, 118, the shoulders 120, 122, and the bottom end 106. The interior surface of the body 102 may be collectively defined by the interior surfaces of the first major wall 112, the second major wall, the side walls 116, 118, the shoulders 120, 122, and the bottom end 106.

[0037] The interior surface and the exterior surface of the body 102 may collectively define a wall thickness of the body 102 or the packaging article 100. The wall thickness of the body 102 may range from about 0.1 mm to about 2 mm - including all values and sub-ranges thereof. For example, in some embodiments, the wall thickness of the packaging article 100 may range from about 0.2 mm to about 2 mm, from about 0.2 mm to about 1.8 mm, from about 0.4 mm to about 1.6 mm, or from about 0.6 mm to 1.4 mm. Depending on the shape and form of the body 102 and/or the manufacturing process, the body 102 may have a generally consistent wall thickness in some embodiments. In some embodiments, the body 102 may have a varying wall thickness. For example, in some embodiments, the side walls 116, 118 may have a wall thickness that may be greater than the wall thickness of the major walls 112. The shoulders 120, 122 may have a wall thickness that may be greater than the wall thickness of the major walls 112 and/or the side walls 116, 118. The bottom end 106 and/or the bottom corners 126, 128 may have a wall thickness greater than the wall thickness of the shoulders 120, 122, the major walls 112, and/or the side walls 116, 118.

[0038] In some embodiments, the packaging article 100 may be produced via extrusion blow molding (EBM), as will be described in more detail below, using a polymer blend. The polymer blend may include a substantially homogeneous blend or mixture of cyclic olefin copolymer (COC) and high-density polyethylene (HDPE). In some embodiments, the homogeneous blend of COC and HDPE may be in the form of pellets. The pellets may be formed from, e.g., via extrusion, a homogeneous blend of COC and HDPE in a melted state. Consequently, the pellets may include a homogeneous blend or mixture of COC and HDPE.

[0039] In some embodiments, the COC may be present in the polymer blend in an amount ranging from about 1 wt. % to about 30 wt. % - including all values and sub-ranges thereof. In some embodiments, the COC may be present in the polymer blend in an amount ranging, e.g., from about 1 wt. % to 25 wt. %, from about 1 wt. % to about 20 wt. %, from about 1 wt. % to about 15 wt. %, from about 1 wt. % to about 10 wt. %, from about 5 wt. % to 25 wt. %, from about 5 wt. % to about 20 wt. %, from about 5 wt. % to about 15 wt. %, from about 5 wt. % to about 10 wt. %, from about 8 wt. % to 25 wt. %, from about 8 wt. % to about 20 wt. %, from about 8 wt. % to about 15 wt. %, from about 10 wt. % to 25 wt. %, or from about 10 wt. % to about 20 wt. %. In one or more examples, the COC is present in the polymer blend in an amount of about 5% to about 15%. In another example, the COC is present in the polymer blend in an amount of about 5%, in an amount of about 8%, in an amount of about 10%, in an amount of about 12%, or in an amount of about 15%.

[0040] In some instances, the inventors have unexpectedly discovered that the improvement in the mechanical strength may be of lesser degree when the amount of COC is greater than or about 10 wt. %. For example, when the amount of COC is about 10 wt. % or less, the mechanical strength of the polymer blend may increase at a greater rate as compared to polymer blends having 10 wt. % or more of COC. Thus, in some examples, the COC is present in an amount of about 10%, about 8%, or about 5%.

[0041] In some examples, because COC generally has a higher modulus than HDPE, the mechanical strength of the polymer blend may generally improve as the amount of COC in the polymer blend increases. Thus, in some embodiments, COC may be present in the polymer blend in an amount of about 10 wt. % or greater to achieve desired mechanical properties of the polymer blend. In order to maintain the recyclability of the polymer blend and/or to balance cost and performance, COC may be present in an amount of up to about 20 wt. %, e.g., less than or about 20 wt. %.

[0042] In some embodiments, the COC used for forming the polymer blend may have a density ranging from about 1.01 g/cm³ to about 1.2 g/cm³ (ISO 1183) - including all values and sub-ranges thereof. In some embodiments, the COC may have a density of about 1.02 g/cm³. In some embodiments, the COC may have a glass transition temperature (Tg) ranging from 100 °C to 180 °C (ISO 11357-1 , -2, -3) - including all values and sub-ranges thereof. In some embodiments, the COC may have a glass transition temperature of about 134 °C. In some embodiments, the COC may have a Vicat softening temperature ranging from about 68 °C to about 178 °C (ISO 306) - including all values and sub-ranges thereof. In some embodiments, the COC may have a Vicat softening temperature of about 133 °C. In some embodiments, the COC may have a melt volume flow rate ranging from about 4 to about 60 cm³/10 min @260 °C/2.16 kg (ISO 1133). In some embodiments, the COC may have a melt volume flow rate of about 48 cm³/10 min @260 °C/2.16 kg-

[0043] In some embodiments, the COC may have a modulus ranging from about 2 GPa to about 6.4 GPa (ISO 527-2/1A or ASTM D638) - including all values and sub-ranges thereof. In some embodiments, the COC may have a modulus of about 3.2 GPa. In some embodiments, the COC may have a tensile strength at break ranging from about 30 MPa to about 70 MPa (ASTM D638) - including all values and sub-ranges thereof. In some embodiments, the COC may have a tensile strength at break of about 46 MPa. In some embodiments, the COC may have an elongation at break ranging from about 1.5% to about 4.5% (ASTM D638) - including all values and sub-ranges thereof. In some embodiments, the COC may have an elongation at break of about 1.7%. In some embodiments, the COC may have an impact value ranging from about 1 KJ/m² to about 5.2 KJ/m² (ISO 527-2/1A or ASTM D638) including all values and sub-ranges thereof. In some embodiments, the COC may have an impact value of about 1.6 KJ/m².

[0044] The COC may have the following general formula:

[0045] In some embodiments, the ethylene repeating units may be present in the COC in an amount ranging from about 20 wt. % to about 90 wt. % - including all values and sub-ranges thereof. In some embodiments, the norbomene repeating units may be present in the COC in an amount ranging from about 10 wt. % to about 80 wt. % - including all values and sub-ranges thereof.

[0046] In some embodiments, the HDPE may be present in the polymer blend in an amount ranging from about 70 wt. % to about 99 wt. %, e.g., from about 75 wt. % to about 99 wt. %, from about 80 wt. % to about 99 wt. %, from about 85 wt. % to about 99 wt. %, from about 90 wt. % to about 99 wt. %, from about 95 wt. % to about 99 wt. %, from about 70 wt. % to about 95 wt. %, from about 75 wt. % to about 95 wt. %, from about 80 wt. % to about 95 wt. %, from about 85 wt. % to about 95 wt. %, from about 90 wt. % to about 95 wt. %, from about 70 wt. % to about 90 wt. %, from about 75 wt. % to about 90 wt. %, from about 80 wt. % to about 90 wt. %, from about 85 wt. % to about 90 wt. %, from about 70 wt. % to about 85 wt. %, from about 75 wt. % to about 85 wt. %, or from about 80 wt. % to about 85 wt. %. In some examples, the HDPE may be present in the polymer blend in an amount of about 85%, 88%, 90%, 92%, of 95%. In some embodiments, the polymer blend may include at least about 80 wt. %, e.g., from about 80 wt. % to about 99 wt. %, of HDPE to allow the polymer blend to be recycled. In some embodiments, the HDPE may be present in the polymer blend in an amount ranging from about 80 wt. % to about 95 wt. % or less. In some embodiments, the HDPE may be present in the polymer blend in an amount ranging from about 80 wt. % to about 90 wt. % or less. In some embodiments, the HDPE may be present in the polymer blend in an amount less than about 90 wt. %.

[0047] In some embodiments, the HDPE may have a density ranging from about 0.93 g/cm³ to about 0.97 g/cm³ - including all values and sub-ranges thereof. In some embodiments, the HDPE may have a density of about 0.953 g/cm³. In some embodiments, the HDPE may include a molecular weight ranging from about 130,000 Dalton to about 300,000 Dalton - including all values and sub-ranges thereof. In some embodiments, the HDPE may include or may be unimodal high-density polyethylene. Thus, the molecular weight distribution curve of the HDPE used for the polymer blend may include only one peak in the distribution. In some embodiments, the distribution may be narrow. In some embodiments, the poly dispersity index may be close to 1.

[0048] In some embodiments, the HDPE may have a melting point ranging from about 120 °C to about 130 °C (ASTM D3418) - including all values and sub-ranges thereof. In some embodiments, the HDPE may have a melting point of about 135 °C. In some embodiments, the HDPE may have a melt index ranging from about 0.01 to about 1.5 g/10 min @ 190 °C/2.16 kg (ASTM D1238). In some embodiments, the HDPE may have a melt index of about 0.35 g/10 min @ 190 °C/2.16 kg.

[0049] In some embodiments, the HDPE may have a modulus ranging from about 0.56 GPa to about 1.5 GPa (ASTM D638) - including all values and sub-ranges thereof. In some embodiments, the HDPE may have a modulus of about 1.37 GPa. In some embodiments, the HDPE may have a tensile strength at yield ranging from about 11 MPa to about 43 MPa (ASTM D638) - including all values and sub-ranges thereof. In some embodiments, the HDPE may have a tensile strength at yield of about 25 MPa. In some embodiments, the HDPE may have an elongation at break ranging from about 3.2% to about 2230% (ASTM D638) - including all values and sub-ranges thereof. In some embodiments, the HDPE may have an elongation at break of about 515 %. In some embodiments, the HDPE may have an Izod impact strength ranging from about 50 J/m to about 400 J/m (ASTM D256) - including all values and sub-ranges thereof. In some embodiments, the HDPE may have an Izod impact strength of about 110 J/m.

[0050] In some embodiments, the HDPE used for forming the polymer blend may include recycled HDPE. In some embodiments, the recycled HDPE may include pigment. In some embodiments, the HDPE used for forming the polymer blend, whether recycled or not, may include pigment. The pigment may include titanium oxide, calcium carbonate, etc. In some embodiments, the pigment may be present in the HDPE in an amount ranging from about 0 wt. % to about 30 wt. %, e.g., from about 0.01 wt. % to about 30 wt. % - including all values and sub-ranges thereof. In some embodiments, the pigment may be present in the polymer blend in an amount ranging from about 0 wt. % to about 20 wt. %, e.g., from about 0.01 wt. % to about 20 wt. % - including all values and sub-ranges thereof, based on the total weight of the polymer blend. In some embodiments, pigment may be added to the polymer blend independent of the HDPE and/or the COC used for forming the polymer blend. In some embodiments, the HDPE used for forming the polymer blend, whether recycled or not, may not include pigment. In some embodiments, the polymer blend may not include pigment.

[0051] As mentioned above, the polymer blend of COC and HDPE may be substantially homogeneous. In some embodiments, the polymer blend may be substantially homogeneous such that the polymer blend may include substantially no phase segregation.

[0052] FIGS. 2A-2F schematically illustrate a process of producing a packaging article as described herein. The packaging article may be produced via extrusion blow molding (EBM) using the polymer blend described herein. In some embodiments, the polymer blend may be provided in the form of pellets or any other suitable form, which may be heated and extruded into a hollow tube or parison that can be fed into an EBM mold as shown in FIG. 2A. As shown in FIG. 2B, the EBM mold may then be closed, gripping the parison in place. With reference to FIG. 2C, compressed air may be blown into the parison, causing the parison to inflate. Once the parison fills the EBM mold as shown in FIG. 2D, the EBM mold may be opened, and the blow molded product may be trimmed and removed from the EBM mold as shown in FIG. 2E, forming an extrusion blow molded product or packaging article, as shown in FIG. 2F. As discussed above, the extrusion blow molded packaging article may have a wall thickness of less than 2 mm, e.g., from about 0.1 mm to about 2 mm, from about 0.2 mm to about 2 mm, from about 0.2 mm to about 1.8 mm, from about 0.4 mm to about 1.6 mm, or from about 0.6 mm to 1.4 mm.

[0053] The polymer blend as described herein may be produced using any suitable methods, such as extrusion. In some embodiments, COC and HDPE may be melt mixed to produce a mixture of the COC and the HDPE. The mixture of the COC and the HDPE may then be extruded. In some embodiments, the extruded mixture of the COC and the HDPE may be pelletized to form pellets of the polymer blend. In some embodiments, after melt mixing, extrusion, and optionally pelletizing, the resultant mixture or blend may be melt mixed, extruded, and optionally pelletized for one or more times. In other words, one or more cycles or repetitions of melt mixing, extrusion, and/or pelletizing may be carried out so as to obtain a substantially homogeneous blend of the COC and the HDPE.

[0054] In one or more examples, a mixture of COC dry pellets and HDPE dry pellets are loaded into a hopper directly for EBM. In another example, a pre-blend of COC and HDPE pellets are made (e.g., by using a two-screw extruder) to produce pellets of pre-blended COC and HDPE (e.g., by melt-mixing), and those dry pellets of the pre -blended COC and HDPE are loaded into a hopper for manufacturing via EBM.

[0055] In some embodiments, the polymer blend may be produced using a twin-screw extruder. In some embodiments, a temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C )/(210 °C to 230 °C) /(230 °C to 250 °C)Z (230 °C to 250 °C)/(220 °C to 240 °C)/(210 °C to 230 °C)/(190 °C to 210 °C) may be used. In some embodiments, a temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C)/(200 °C to 220 °C)/(210 °C to 230 °C)/(210 °C to 230 °C)/(200 °C to 230 °C)/(190 °C to 210 °C)/(170 °C to 190 °C) may be used. In some embodiments, when multiple cycles or repetitions of melt mixing and extrusion may be performed, the temperature profile for each cycle or repetition of melt mixing and extrusion may be the same or may vary from cycle to cycle. In some embodiments, a temperature profile that have one or more reduced temperatures may be implemented in subsequent cycle(s) since the homogeneity of the polymer blend may generally improve as more cycles of melt mixing and extrusion are performed.

[0056] Implementation of the present disclosure is provided by way of the following examples. The examples serve to illustrate the technology without being limiting in nature. EXAMPLES

Experiment 1

[0057] Non-limiting exemplary polymer blends with different COC contents in accordance with some embodiments were made through extrusion using a twin-screw extruder. For each blend, two or three cycles of melt mixing and extrusion were performed. During the first two cycles, the temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C )/(210 °C to 230 °C) /(230 °C to 250 °C)Z (230 °C to 250 °C)/(220 °C to 240 °C)/(210 °C to 230 °C)/(190 °C to 210 °C) with the screw rotation of 60 rpm was used. During the third cycle (if performed), the temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C)/(200 °C to 220 °C)/(210 °C to 230 °C)/(210 °C to 230 °C)/(200 °C to 230 °C)/(190 °C to 210 °C)/(170 °C to 190 °C) with the screw rotation of 60 rpm was used.

[0058] Table 1 lists Examples 1-6 of the polymer blends produced using the process described above. Table 1 further lists Comparative Examples 1-3. As also listed in Table 1, some of the examples and comparative examples were made using HDPE containing pigment, such as titanium oxide.

Table 1

[0059] Dog bone specimens were prepared using polymer blends of Examples 1-6 and Comparative Examples 1-3 through injection molding with a temperature of 250 °C under 450 psi pressure.

[0060] FIG. 3 shows the mechanical properties, in particular, Young’s modulus and elongation at break, of the various dog bone specimens. As shown, increasing the number of extrusion cycles and/or increasing the amount of COC in the polymer blends improved the mechanical strength of the polymer blends. Additionally, the inclusion of pigment also increased the rigidity of the polymer blends.

Experiment 2

[0061] FIGS. 4A and 4B are scanning electron microscope (SEM) images showing the morphology of the polymer blend Example 2 and the polymer blend Example 5, respectively. FIGS. 5A-5C are atomic force microscope (AFM) images showing the morphology of Comparative Example 1, Comparative Example 3, and the polymer blend Example 2, respectively. The inventors have unexpectedly discovered that no phase segregation existed in the polymer blend examples, as shown in the SEM or AFM images. White dots in the SEM images were titanium oxide particles. The lack of phase segregation indicates that the polymer blends of COC and HDPE as described herein are substantially homogeneous.

Experiment 3

[0062] Non-limiting exemplary packaging articles were made via extrusion blow molding using polymer blend Examples 7, 8, and 9 as listed in Table 2 and pure HDPE (Comparative Example 4). Different from Experiment 1 where the polymer blend Examples 1-6 were made via melt mixing followed by extrusion through two to three cycles, polymer blend Examples 7-9 were only dry mixed and then fed into the extrusion blowing molding machine through one cycle for making the packaging articles.

Table 2

[0063] FIG. 6 shows the force at yield in the top load tests and major wall load tests of the packaging articles. The top load tests showed that increasing the amount of COC in the polymer blend up to 20 wt. % improved the force at yield of the packaging article by 11% compared to the packaging article made from 100 wt. % HDPE without COC or pigment. In the major wall load tests, the force at yield of the packaging articles made from polymer blends containing COC was comparable to the force at yield of the packaging article made from 100 wt. % HDPE without COC, although a slight decrease was observed. Without intending to be bound by theory, the slight decrease in the force at yield in the major wall load tests could be related to the reduced wall thickness of the major walls of the packaging articles made from the polymer blends containing coc.

[0064] FIG. 7 shows the wall thicknesses of various portions of the packaging article. Overall, packaging articles with higher COC contents (e.g., 10 wt. % and 20 wt. %) had lower wall thicknesses, especially in the major walls, as compared to the packaging article made from 100 wt. % HDPE without COC. The results from FIGS. 6 and 7 demonstrate that by using polymer blends of COC and HDPE, reduction in wall thickness and/or weight of the packaging articles, and thus, overall plastic usage, may be achieved while providing mechanical properties comparable to, or even better than, packaging articles made from 100 wt. % HDPE without COC.

Experiment 4

[0065] Non-limiting exemplary polymer blends with different COC contents (5, 8, 10, 12 and 15%) in accordance with some embodiments were made through extrusion using an extruder. The blended pellets were made through extrusion. The temperature profile used during processing for all three cycles was 160/190/220/240/240/230/220/200°C with a screw rotation of 60 rpm. To obtain better dimensional stability of the pellets, each blended example coming out of the extruder was cooled in water. Then, the dog-bone specimens were prepared by injection molding at a temperature of 250 °C under the 450 psi pressure. Mechanical and morphological properties of dogbone specimens were characterized. In the second step, resins were blended with three cycles of extrusion, and the pre -blended pellets were made with three different weights (30, 36 and 42 gram). The mechanical and physical properties of the prepared bottles (0/100, 5/95, 8/92 and 12/88 COC/HDPE) were tested.

Table 3

[0066] FIG. 8 illustrates the tensile strength and elongation of the examples and FIG. 9 illustrates the Young modulus of the examples and comparison 5 of table 3. Overall, by increasing COC, elongation decreases while tensile strength and rigidity increases. Examples made with 8% and 12% COC showed highest tensile strength among all which was about 20% improvement compared to the control example. Based on Figure 9, 15% example had highest rigidity, while “15% no extrusion” example showed highest elongation with low rigidity and strength and that could be representative of the heterogeneity of the prepared examples in the injection molding process. This data indicates the importance of preparing using extrusion before injection molding on the mechanical properties improvement. Based on this data, bottles made out of 5, 8 and 12% COC using pre-blending process and their physical and mechanical properties have been investigated.

[0067] FIGS. 10A to 10G illustrate the morphology of the dog-bone specimens of Table 3 through atomic force microscopy (AMF). FIG. 10A is an image of comparison 5 having 100% HDPE, FIG. 10B is an image of Ex. 10, FIG. 10C is an image of Ex. 11, FIG. 10D is an image of Ex. 12, FIG. 10E is an image of Ex. 13, FIG. 10F is an image of Ex. 14, and FIG. 10G is an image of Ex. 15. As shown in the images, no clear phase separation was observed by AFM for the examples made via injection molding.

Table 4

[0068] FIGS. 11 to 13 illustrate the thickness distribution of the comparisons and examples of Table 4. Specifically, FIG. 11 illustrates 100% HDPE (Comp. 6), 5% COC/HDPE (Ex. 17), 8% COC/HDPE (Ex. 18), and 12% COC/HDPE (Ex. 19) bottles with 42 g weight. FIG. 12 illustrates the thickness distribution of 100%HDPE (Comp. 7), 5% COC/HDPE (Ex. 20), 8% COC/HDPE (Ex. 21), and 12% COC/HDPE (Ex. 22) bottles with 36 g weight. FIG. 13 the thickness distribution of 100%HDPE (Comp. 8), 5% COC/HDPE (Ex. 23), 8% COC/HDPE (Ex. 24), and 12% COC/HDPE (Ex. 25) bottles with 30 g weight. Control bottles, represented as comparisons, exhibited high thickness in the shoulder and side wall portions, and low thickness in the major wall portion. By adding COC, the thickness of flat and bottom parts of bottles increased. Based upon the data herein, the added COC improved the processability and homogeneity of the examples.

[0069] Referring to FIG. 14, the mechanical properties of the examples in Table 4 were tested with a top load test. In the top load test, the force at yield for top load was tested. As shown in FIG. 14, adding 8% COC increased 17% and 20% of bottle strength in 42 g and 36 g bottles respectively. No significant increase was observed in 30 g bottles.

[0070] The examples of Table 4 were also subject to a drop test. Drop test has been tested for all three weights of bottles (30, 36 and 42 g). Results showed that none of the 8% bottles leaked within 6 times of dropping, and many of the examples exhibited some damage and leaking around the bottom comer area of those bottles. Contrarily, most damage to the control bottles were located in the middle flat area. Due to high thickness of the side wall of the control bottles, not major side wall damage was observed. No leaking was observed for control bottles but some damage was observed in the side/middle part of bottles. Two of 12% COC bottles at all weights (30, 36 and 42%) exhibited leaking from bottom area after two to three times of dropping.

[0071] Referring to FIGs. 15A to 15D, the bottles from examples 18 and 19 were further observed and compared to example 9 via atomic force microscopy to study the morphology of the examples. FIG. 15A illustrates Comp. 6 having 100% HDPE, FIG. 15B illustrates Ex. 18 having 8% COC, FIG. 15C illustrates Ex. 19 having 12% COC, and FIG. 15D illustrates Ex. 9 having 20% COC. As shown in FIGs. 15A to 15D, no significant phase segregation was observed in 8% bottle while some phase separation was observed in 12% and 20% bottle.

[0072] Referring to FIGs. 16A to 16D, the bottles from examples 17, 18, and 19 were further observed via atomic force microscopy to study the morphology of the examples. FIG. 16A illustrates Comp. 6 having 100% HDPE, FIG. 16B illustrates Ex. 17 having 5% COC, FIG. 16C illustrates Ex. 18 having 8% COC, and FIG. 16D illustrates Ex. 19 having 12% COC. As shown in FIGs. 16A to 16D, no significant phase segregation was observed in 8% bottle.

[0073] Referring to FIGs. 17 A to 17D (4X magnification) and 18A to 18D (20X magnification), the bottles from examples 17. 18, and 19 were further observed via scanning electron microscopy to study the morphology of the examples. FIG. 17A illustrates Comp. 6 having 100% HDPE, FIG. 17B illustrates Ex. 17 having 5% COC, FIG. 17C illustrates Ex. 18 having 8% COC, and FIG. 17D illustrates Ex. 19 having 12% COC. FIG. 18A illustrates Comp. 6 having 100% HDPE, FIG. 18B illustrates Ex. 17 having 5% COC, FIG. 18C illustrates Ex. 18 having 8% COC, and FIG. 18D illustrates Ex. 19 having 12% COC. As shown in the images, no significant phase segregation was observed in 8% bottle.

[0074] To summarize, the dog-bone examples (control, 5%, 8%, 12% and 15%) prepared using pre-blending through extruder and processed by injection molding exhibited no phase separation in any HDPE/COC examples. It is understood that a higher content of COC into HDPE causes non-recyclability issues as well as increases the cost, thus it is advantageous to control the COC content to balance mechanical and recyclability properties. Based on properties of prepared dogbone examples, it was observed that pre-blending of two resins helps homogenizing the example while improving the properties. As a result, bottles were made using 5/95, 8/92 and 12/88 %wt. pre-blended COC/HDPE resins through an EBM method. AFM of 8% bottles reveled no phase separation which indicates a good homogeneity of COC within HDPE matrix. According to the top load and drop test results, decreasing the weight of bottle for 15% wt. COC (42 to 36 g) along with 8% wt. COC in the matrix achieves similar performance as pure HDPE at a weight of 42 g. It is also observed that the presence of COC improves the bottle processing and uniformity by changing the rate of crystallinity.

EXEMPLARY CLAIM SET

[0075] Exemplary Claim 1. A packaging article produced via extrusion blow molding using a polymer blend, wherein: the polymer blend comprises cyclic olefin copolymer and high-density polyethylene; the polymer blend is substantially homogeneous; and the cyclic olefin copolymer is present in the polymer blend in an amount equal to or greater than 8 wt. %.

[0076] Exemplary Claim 2. The packaging article according to claim 1, wherein the cyclic olefin copolymer is present in the polymer blend in an amount of up to about 20 wt. %.

[0077] Exemplary Claim 3. The packaging article according to any one of claims 1 to 2, wherein the polymer blend has substantially no phase segregation.

[0078] Exemplary Claim 4. The packaging article according to any one of claims 1 to 3, wherein the cyclic olefin copolymer has a melting point ranging from about 75 °C to 185 °C. [0079] Exemplary Claim 5. The packaging article according to any one of claims 1 to 4, wherein the high-density polyethylene is present in the polymer blend in an amount ranging from about 80 wt. % to about 95 wt. %.

[0080] Exemplary Claim 6. The packaging article according to any one of claims 1 to 5, wherein the high-density polyethylene has a density ranging from about 0.93 g/cm³ to about 0.97 g/cm³ or about 0.953 g/cm³.

[0081] Exemplary Claim 7. The packaging article according to any one of claims 1 to 6, wherein the high-density polyethylene has a molecular weight ranging from about 130,000 Dalton to about 300,000 Dalton.

[0082] Exemplary Claim 8. The packaging article according to any one of claims 1 to 7, wherein the high-density polyethylene comprises unimodal high-density polyethylene.

[0083] Exemplary Claim 9. The packaging article according to any one of claims 1 to 8, wherein the polymer blend further comprises pigment.

[0084] Exemplary Claim 10. The packaging article according to claim 9, wherein the pigment is present in the polymer blend in an amount ranging from about 0.01 wt. % to about 20 wt. %.

[0085] Exemplary Claim 11. The packaging article according to any one of claims 1 to 10, wherein: the packaging article comprises an interior surface and an exterior surface collectively defining a wall thickness of the packaging article; and the wall thickness of the packaging article is about 2 mm or less.

[0086] Exemplary Claim 12. A packaging article produced via extrusion blow molding using a polymer blend, wherein: the polymer blend comprises cyclic olefin copolymer and high-density polyethylene; the polymer blend is substantially homogeneous; the cyclic olefin copolymer is present in the polymer blend in an amount ranging from about 5 wt. % to about 20 wt. %; the packaging article produced via extrusion blow molding comprises an interior surface and an exterior surface collectively defining a wall thickness of the packaging article; and the wall thickness of the packaging article is about 2 mm or less.

[0087] Exemplary Claim 13. A method of producing a packaging article, comprising providing a polymer blend, and forming the packaging article from the polymer blend via extrusion blow molding; wherein: the polymer blend comprises cyclic olefin copolymer and high-density polyethylene; the polymer blend is substantially homogeneous; the cyclic olefin copolymer is present in the polymer blend in an amount ranging from about 5 wt. % to about 20 wt. %; and the packaging article formed via extrusion blow molding comprises an interior surface and an exterior surface collectively defining a wall thickness of the packaging article; and the wall thickness of the packaging article is about 2 mm or less.

[0088] Exemplary Claim 14. The method of claim 13, wherein the polymer blend comprises pellets.

[0089] Exemplary Claim 15. The method of any one of claims 13 to 14, wherein the polymer blend is formed by: a) melt mixing cyclic olefin copolymer and high-density polyethylene to produce a mixture of the cyclic olefin copolymer and the high-density polyethylene; and b) extruding the mixture of the cyclic olefin copolymer and the high-density polyethylene.

[0090] Exemplary Claim 16. The method of claim 15, wherein the polymer blend is formed by further: c) pelletizing the extruded mixture of the cyclic olefin copolymer and the high-density polyethylene.

[0091] Exemplary Claim 17. The method of any one of claims 15 to 16, wherein the polymer blend is formed by further repeating steps a) and b).

[0092] Exemplary Claim 18. The method of claim 17, wherein a same temperature profile is used in every repetition of steps a) and b).

[0093] Exemplary Claim 19. The method of any one of claims 15 to 18, wherein during step a), a temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C )/(210 °C to 230 °C) /(230 °C to 250 °C)/ (230 °C to 250 °C)/(220 °C to 240 °C)/(210 °C to 230 °C)/(190 °C to 210 °C) is used.

[0094] Exemplary Claim 20. The method of any one of claims 15 to 19, wherein during step b), a temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C)/(200 °C to 220 °C)/(210 °C to 230 °C)/(210 °C to 230 °C)/(200 °C to 230 °C)/(190 °C to 210 °C)/(170 °C to 190 °C) is used.

[0095] Exemplary Claim 21. The method of any one of claims 15 to 20, wherein the polymer blend is formed using a twin-screw extruder.

Claims

CLAIMS What is claimed is:

1. A packaging article produced via extrusion blow molding using a polymer blend, wherein: the polymer blend comprises: cyclic olefin copolymer; and high-density polyethylene; the polymer blend is substantially homogeneous; and the cyclic olefin copolymer is present in the polymer blend in an amount equal to or greater than 8 wt. %.

2. The packaging article according to claim 1, wherein the cyclic olefin copolymer is present in the polymer blend in an amount of up to about 20 wt. %.

3. The packaging article according to any one of claims 1 to 2, wherein the polymer blend has substantially no phase segregation.

4. The packaging article according to any one of claims 1 to 3, wherein the cyclic olefin copolymer has a melting point ranging from about 75 °C to 185 °C.

5. The packaging article according to any one of claims 1 to 4, wherein the high-density polyethylene is present in the polymer blend in an amount ranging from about 80 wt. % to about 95 wt. %.

6. The packaging article according to any one of claims 1 to 5, wherein the high-density polyethylene has a density ranging from about 0.93 g/cm³ to about 0.97 g/cm³ or about 0.953 g/cm³.

7. The packaging article according to any one of claims 1 to 6, wherein the high-density polyethylene has a molecular weight ranging from about 130,000 Dalton to about 300,000 Dalton.

8. The packaging article according to any one of claims 1 to 7, wherein the high-density polyethylene comprises unimodal high-density polyethylene.

9. The packaging article according to any one of claims 1 to 8, wherein the polymer blend further comprises pigment.

10. The packaging article according to claim 9, wherein the pigment is present in the polymer blend in an amount ranging from about 0.01 wt. % to about 20 wt. %.

11. The packaging article according to any one of claims 1 to 10, wherein: the packaging article comprises an interior surface and an exterior surface collectively defining a wall thickness of the packaging article; and the wall thickness of the packaging article is about 2 mm or less.

12. A packaging article produced via extrusion blow molding using a polymer blend, wherein the polymer blend comprises: cyclic olefin copolymer; and high-density polyethylene; the polymer blend is substantially homogeneous; the cyclic olefin copolymer is present in the polymer blend in an amount ranging from about 5 wt. % to about 20 wt. %; the packaging article produced via extrusion blow molding comprises an interior surface and an exterior surface collectively defining a wall thickness of the packaging article; and the wall thickness of the packaging article is about 2 mm or less.

13. A method of producing a packaging article, comprising: providing a polymer blend; and forming the packaging article from the polymer blend via extrusion blow molding; wherein: the polymer blend comprises: cyclic olefin copolymer; and high-density polyethylene; the polymer blend is substantially homogeneous; the cyclic olefin copolymer is present in the polymer blend in an amount ranging from about 5 wt. % to about 20 wt. %; the packaging article formed via extrusion blow molding comprises an interior surface and an exterior surface collectively defining a wall thickness of the packaging article; and the wall thickness of the packaging article is about 2 mm or less.

14. The method of claim 13, wherein the polymer blend comprises pellets.

15. The method of any one of claims 13 to 14, wherein the polymer blend is formed by: a) melt mixing cyclic olefin copolymer and high-density polyethylene to produce a mixture of the cyclic olefin copolymer and the high-density polyethylene; and b) extruding the mixture of the cyclic olefin copolymer and the high-density polyethylene.

16. The method of claim 15, wherein the polymer blend is formed by further: c) pelletizing the extruded mixture of the cyclic olefin copolymer and the high-density polyethylene.

17. The method of any one of claims 15 to 16, wherein the polymer blend is formed by further repeating steps a) and b).

18. The method of claim 17, wherein a same temperature profile is used in every repetition of steps a) and b).

19. The method of any one of claims 15 to 18, wherein during step a), a temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C )/(210 °C to 230 °C) /(230 °C to 250 °C)/ (230 °C to 250 °C)/(220 °C to 240 °C)/(210 °C to 230 °C)/(190 °C to 210 °C) is used.

20. The method of any one of claims 15 to 19, wherein during step b), a temperature profile of (150 °C to 170 °C)/(180 °C to 200 °C)/(200 °C to 220 °C)/(210 °C to 230 °C)/(210 °C to 230 °C)/(200 °C to 230 °C)/(190 °C to 210 °C)/(170 °C to 190 °C) is used.

21. The method of any one of claims 15 to 20, wherein the polymer blend is formed using a twin-screw extruder.