HK1156650B - Polymeric compositions and articles comprising polylactic acid and polyolefin - Google Patents

Description

Polymer compositions and articles comprising polylactic acid and polyolefins

Technical Field

The present invention relates to polymer compositions comprising polylactic acid (PLA), polyolefin, and optionally a non-reactive melt strength enhancing additive (NRMSEA), as well as articles molded from the compositions and methods of making the compositions.

Background

Polyolefins are now found in widespread use in many applications, from packaging to functional products such as medical devices and disposable consumer products. They are not only safe, but also lightweight and relatively inexpensive. Polyolefins are relatively easy to melt process into their final form by various shaping operations, and also are easily recycled due to their good thermal stability and inert character. They are ubiquitous in modern society due to such diverse characteristics.

Currently commercially available polyolefins are derived from petroleum and/or natural gas, which are limited natural resources. Since the sources of polyolefins are limited, the price of polyolefins is linked to the price fluctuations of crude oil and natural gas. Recently, there has been an increase in economic, social, environmental and political pressure to reduce reliance on limited resources, such as oil and gas, and to replace them with materials derived from renewable feedstocks. Most desirably, such renewable materials have processability and performance characteristics and cost structure similar to those of conventional polyolefins. It is also desirable that such renewable materials maintain the recyclability of traditional polyolefins and not significantly alter the recycling infrastructure of High Density Polyethylene (HDPE) in today's locations.

An example of a renewable thermoplastic material is polylactic acid (PLA), which is an aliphatic polyester derived from renewable agricultural products. PLA has been used in many applications, such as water bottles and blister packaging for freshness processes, to completely replace polyolefin or polyethylene terephthalate (PET). However, PLA has not gained widespread use due to its limited processability (i.e., poor melt strength, which does not allow it to be extrusion blow molded into bottles), limited recyclability (i.e., lack of specialized recycle streams that may contaminate PET recycle streams, as described below), and other adverse properties of the material (i.e., low heat distortion temperature, poor water barrier, poor resistance to solvents and surfactants encountered in non-food packaging applications).

Efforts have been made to alter some of the properties of PLA (i.e., poor melt strength) by adding other components to lower concentrations (less than about 50 wt%) of PLA. For example, polyolefins and copolymers thereof have been added to PLA at concentrations of less than about 50 wt% to improve the impact properties of PLA. However, unlike the processing of polyolefins, such as HDPE, the processing of such PLA and polyolefin blends requires additional pre-processing steps and the use of twin screw extruders as well as Reactive Melt Strength Enhancing Additives (RMSEA) to achieve adequate dispersion of the minor polyolefin phase in the PLA continuous phase. Pre-processing entails melting, mixing, cooling, solidifying PLA and polyolefin pellets, then cutting into PLA/polyolefin pellets, which are then fed into a twin screw extruder. The use of twin screw extruders and/or RMSEA significantly increases the cost and complexity of the production process. In extrusion blow molding, the molder typically incorporates a single screw extruder rather than a twin screw extruder. For RMSEA, the use of these additives requires monitoring and greater control of the production process. The use of RMSEA also requires a purification step to remove unreacted reactants and it can produce volatile products that must be vented using a twin screw extruder. Thus, the past teaches that blends of PLA and polyolefin cannot simply replace polyolefins such as HDPE and be processed on conventional polyolefin processing stations (i.e., conventional extrusion blow molding stations) using a single screw extruder and without pre-processing or using RMSEA.

Furthermore, such products cannot be recovered at present due to the difficulty in separating such products made from PLA and polyolefin mixtures from the main PET recovery stream. There are two main plastic recycling streams: HDPE flow and PET flow (PET is a clear plastic that is contaminated with HDPE to the detriment of its clarity, i.e. PET becomes cloudy). Before recycling, the two plastics are separated by density using a water-based separation system. The density of PET is greater than that of water by 1g/cm³Which sinks in the water-based separation system. The density of HDPE is less than 1g/cm³And it floats in the water-based separation system. Containers made from blends of HDPE and PLA having a density greater than 1g/cm³Wherein the concentration of PLA is about 30% or greater. Such containers sink in water-based separation systems and therefore contaminate the PET stream.

Thus, there remains a need for polymer compositions comprising renewable polymers that are comparable to the processability, performance, recyclability, and cost of polyolefins.

Disclosure of illustrative embodiments

The present invention relates to compositions for producing articles comprising renewable materials, in particular polymer compositions for moulding into such articles. The composition comprises PLA at a concentration of greater than about 0.1 wt% and polyolefin at less than about 15 wt%, and optionally NRMSEA. NRMSEA may or may not be included in the composition, depending on the concentration of PLA in the composition.

Also provided is a method of making an article comprising PLA at a concentration of greater than about 0.1 wt% and less than about 15 wt%, a polyolefin, and optionally NRMSEA. Depending on the concentration of PLA, NRMSEA may or may not be included.

Detailed description of illustrative and preferred embodiments

While the specification concludes with claims particularly pointing out and distinctly claiming the invention, it is believed that the present invention will be better understood from the following description.

The present invention relates to a polymer composition comprising a mixture of PLA, polyolefin, and optionally NRMSEA.

As used herein, the term "renewable" refers to a natural resource that is replenished by natural processes at a rate comparable to the rate at which it is consumed by a user. Natural resources that can be referred to as renewable resources include oxygen, fresh water, wood, and plants.

All percentages, parts and ratios are based on the total weight of the composition of the present invention, unless otherwise specified. Unless otherwise indicated, all such weights as they pertain to listed ingredients are based on the active level and, therefore, do not include solvents, catalysts, residual monomers, contaminants, or by-products that may be included in commercially available materials. The term "weight percent" herein may be expressed as "% by weight".

Unless otherwise indicated, all amounts, including parts, percentages, and ratios, are understood to be modified by the word "about," and amounts are not intended to indicate significant digits. The articles "a", "an" and "the" mean "one or more", unless stated otherwise.

I. Polylactic acid

The polymer compositions described herein comprise polylactic acid. PLA is generally a homopolymer or copolymer derived from renewable starch-rich materials such as corn, sugarcane, wheat, and rice. Lactic acid is produced from this starch-rich source using bacterial fermentation. PLA is typically prepared by polymerization of lactic acid. However, one skilled in the art will recognize that chemically equivalent materials can be prepared by polymerization of lactide, a derivative of lactic acid. Likewise, as used herein, the term "PLA" is intended to mean a polymer prepared by polymerization of lactic acid or lactide.

Examples of PLA polymers suitable for use in the present invention include a variety of PLA polymers available from NatureWorks LLC, Minnetonka, Minnesota.

It is generally desirable that PLA be melt processable. Thus, it is desirable that PLA exhibit a melt flow rate at about 210 ℃ of preferably between about 0.1g/10min to about 1000g/10min, preferably between about 1g/10min to about 200g/10min, and more preferably between about 5g/10min to about 50g/10 min. The melt flow rate of a material can be determined according to ASTM test method D1238-E, which is incorporated herein by reference in its entirety.

It is generally desirable that the amount of PLA present in the polymer composition be effective so that the composition exhibits desirable processability, mechanicals, and recyclability. If the concentration of PLA present in the polymer composition is too great, the composition will generally exhibit poor processability (i.e., melt strength) and poor recyclability.

In certain embodiments, PLA is present in the polymer composition at a concentration of about 0.1 wt% to 10 wt%, more preferably between about 1 wt% and about 8 wt%, preferably between about 2 wt% and about 6 wt%, and more preferably about 5 wt%, all weight percentages being based on the total weight of polyolefin, PLA, optional NRMSEA, and optional additives in the composition.

In some embodiments, PLA is present in the polymer composition at a concentration of about 10 wt% to about 15 wt%, preferably between about 11 wt% and about 14 wt%, preferably about 13 wt%. When PLA is present in the polymer composition at a concentration greater than about 10 wt%, the composition typically also includes NRMSEA. When the concentration of PLA is less than 10 wt%, NRMSEA may or may not be present.

Polyolefins

Generally, any polyolefin capable of being processed into an article is suitable for use in the present invention. The term polyolefin refers to a homopolymer of an olefin or a copolymer of an olefin and another comonomer, which may or may not be an olefin. Polyolefins include, but are not limited to, linear or branched polyalphaolefins and cyclic polyolefins. Non-limiting examples of linear polyalphaolefins include High Density Polyethylene (HDPE) and polypropylene (PP). A non-limiting example of a branched poly-alpha-olefin homopolymer is Low Density Polyethylene (LDPE). A non-limiting example of a branched poly alpha olefin copolymer is Linear Low Density Polyethylene (LLDPE). Non-limiting examples of polyethylene copolymers include poly (ethylene-vinyl acetate), poly (ethylene-maleic anhydride), and poly (ethylene-vinyl alcohol).

HDPE is generally a homopolymer of ethylene or a copolymer of ethylene and another alpha-olefin, the final solid polymer concentration being about 0.945g/cm³And 0.968g/cm³In the meantime. PP is generally a homopolymer of propylene or a copolymer of propylene and a comonomer, wherein the propylene content is greater than about 75 mole%.

In some embodiments, the polyolefin is a homopolymer or copolymer selected from the group consisting of: HDPE, LDPE, LLDPE, and mixtures thereof. In a further embodiment, the polyolefin is a HDPE homopolymer or copolymer. Suitable HDPE polymers are known and available, for example, from INEOS Olefins&Polymers USA (League City, TX) polyethylene copolymer named B54-25H-127, or under the name Paxon^TMAA60-003From ExxonMobil Corp. (Irving, TX).

It is generally desirable that the amount of polyolefin present in the polymer composition be effective such that the composition exhibits the desired properties. If the polyolefin is present in the polymer composition at too low a concentration, the composition will generally exhibit poor extrusion processability, i.e., exhibit low extrusion strength, rough extrudate, sticking to the die or mold. Also, if the polyolefin is present in the polymer composition at too low a concentration, containers produced from the composition by a forming process such as extrusion blow molding may have poor appearance and poor mechanical properties.

In certain embodiments, the polyolefin polymer is present in the polymer composition at a concentration of about 80 weight percent to about 99.9 weight percent, more preferably between about 85 weight percent and about 98 weight percent, and preferably between about 90 weight percent and about 95 weight percent, wherein all weight percents are based on the total weight of the polyolefin, PLA, optionally NRMSEA, and any optional additives in the polymer composition.

Non-reactive melt strength enhancing additives

In certain embodiments, the polymer compositions described herein comprise a non-reactive melt strength enhancing additive (NRMSEA). As used herein, NRMSEA is defined as an additive that improves the melt strength of a composition, for example, to enable the composition to be blow molded into a container using typical extrusion blow molding equipment. NRMSEA also improves the surface finish of the cast product, ultimately resulting in improved surface quality of the blow-molded part. In contrast to RMSEA, NRMSEA generally does not form a permanent covalent bond with the other components of the composition.

The non-reactive nature of NRMSEA is believed to contribute to the processability and recyclability of the product polymer composition. NRMSEA can improve the processability of a polymeric composition comprising PLA and polyolefin, particularly when PLA is present at a concentration of greater than about 10 wt% or when complex containers are produced from the polymeric composition. The complexity of the container is related to the geometry of the container. For example, a simple container would be symmetrical, have a large radius of curvature and have few sharp corners. The complex container will be asymmetric, for example elliptical, with many sharp corners. Likewise, in some cases, the design of a die-off single screw extruder for an extrusion blow molding process may require the addition of NRMSEA to improve the processability of the polymer composition. Inclusion of colorants or other additives may likewise require the addition of NRMSEA.

In some embodiments, NRMSEA is ethylene, CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴Of (2), wherein R is¹Is hydrogen or alkyl having 1 to 8 carbon atoms, R²Is an alkyl radical having from 1 to 8 carbon atoms, R³Is hydrogen or alkyl having 1 to 6 carbon atoms, and R⁴Is a glycidyl group. In certain embodiments, the NRMSEA is an ethylene copolymer of ethylene, butyl acrylate, and glycidyl methacrylate, or a blend of an ethylene copolymer and an ionomer, or an ethylene blend of ethylene and an acrylate or vinyl acetate, or an acrylic copolymer of methyl methacrylate, butyl acrylate, butyl methacrylate, and optionally, styrene. Examples of suitable NRMSEAs include those available under the trade name dupont De nerves and Company (Wilmington, Delaware), e.g., asStrong 100andStrong 120 ethylene copolymer and having the trade name Biostrength available from Arkema Inc. (Philadelphia, Pennsylvania)^TM 130、Biostrength^TM150. And Biostrength^TM700 to a polymer.

It is generally desirable that the amount of NRMSEA present in the polymer composition be effective to cause the composition to exhibit the desired properties, i.e., surface finish and melt strength of the molten product. Generally, the weight ratio of NRMSEA to PLA is present in the polymer composition from about 1: 1 to about 1: 25, more preferably from about 1: 8 to about 1: 12, and preferably about 1: 10.

Optional Components

While the major components of the polymer compositions have been described in the foregoing, these compositions are not so limited and may include other components that do not adversely affect the desired properties of the compositions. Exemplary materials that can be used as additional components include, but are not limited to, dyes, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, plasticizers, nucleating agents, physical and chemical blowing agents, particulates, starches, and additional materials that enhance processability of the polymer composition. If such additional components are included in the polymer composition, it is generally desirable that such additional components be used in an amount of preferably less than about 5 weight percent, more preferably less than about 3 weight percent, and preferably less than about 1 weight percent, wherein all weight percents are based on the total weight of the polyolefin, PLA, optionally, NRMSEA, and any such optional additives present in the composition.

V. Process for preparing Polymer compositions

Generally, the processing steps for the polymer compositions of the present invention are largely the same as those known in the art for processing polyolefins, such as HDPE. The equipment used, i.e., the extrusion blow molding machine, the dies, and the molds, and the processing conditions, i.e., time, pressure, temperature, are also the same as those used in conventional polyolefin processing.

As an initial step, the polymer, PLA and polyolefin, optional NRMSEA and any other optional components may be physically mixed (in any order), each in pellet or powder form, to form a dry blend of the polymer composition. In some embodiments, the composition dry mixture may then be mixed at room temperature with shaking, stirring, or otherwise mixing to mix the components such that a substantially macroscopically homogeneous mixture is formed. The term "microscopically homogeneous" as used herein means that the particle size of the mixture is uniformly on a 10 to 50 μm scale as determined by electron microscopy. As used herein, the term "macroscopically homogeneous" means that the gradation ratio of about 1000 polymer pellets or powder particles of a mixture is uniform, but the gradation ratio of a few pellets or powder particles is not uniform. The mixture can then be melt mixed in, for example, a single screw extruder to distribute and disperse the components so that a substantially microscopically homogeneous melt mixture is formed. Optionally, the substantially microscopically homogeneous molten mixture may then be separately cooled, i.e., in a quench tank.

More typically, however, the substantially microscopically homogeneous molten mixture is delivered directly to the molding apparatus through a die using a single screw mixing apparatus, i.e., the pressure generated by the extrusion blow molding apparatus in which the mixture is molded and cooled. It is generally desirable that the melting or softening temperature of the polymer composition be within the range typically encountered in most applications.

Other methods of mixing, melting and molding the components of the thermoplastic mixture are also acceptable and will be readily recognized by those skilled in the art. For example, when NRMSEA is included in the polymer composition, the polyolefin and PLA polymer may be first dried and melt mixed together, and then the NRMSEA may be added to the molten polyolefin/PLA mixture (which may be subsequently melt mixed). Alternatively, the polyolefin or PLA and NRMSEA together may be first dried and melt blended, and then the remaining polymer (polyolefin or PLA) may be added to the molten polymer/NRMSEA mixture (which may then be melt blended). Typically, when NRMSEA is included in a dry blend of polymer compositions, all three components of the blend are: the polyolefin, PLA and NRMSEA are dried and melt mixed together. Other methods of mixing the components of the present invention together are also acceptable and will be readily recognized by those skilled in the art.

It is desirable that the polyolefin and PLA polymer, and optionally the NRMSEA, remain substantially unreacted with each other in the mixture so that a copolymer comprising any of the various components is not formed. To determine whether the various components are substantially unreacted, analytical techniques such as nuclear magnetic resonance and infrared analysis can be used to evaluate the chemistry of the final polymer mixture.

For molding, the components of the polymer dry mixture: the polyolefin and PLA, and optionally NRMSEA, are molded in a single screw extruder. To produce a polymer composition having the desired properties and performance, more complex molding equipment, such as a twin screw extruder, may be used, but this is not required. Pre-processing of the polymer composition, i.e.pre-melting of certain components, is likewise not required. In particular, the polymer compositions generally exhibit improved processability properties compared to polymer compositions comprising greater than about 15 wt% PLA.

Articles prepared from the polymer compositions

The polymer compositions described herein can be molded into various articles, including products and product packaging, i.e., containers. The composition may be extrusion blow molded or injection molded depending on the product or package. Typically, the compositions described herein are used in an extrusion blow molding process. The polymer compositions of the present invention are suitable for the production of articles, such as personal care products, furniture cleaning products, and laundry detergent products, and packaging for such articles. Personal care products include cosmetics, hair care, skin care, oral care products, i.e. shampoos, soaps, toothpastes. Accordingly, other aspects of the invention relate to product packaging, such as containers or bottles, comprising the polymer compositions described herein. As used herein, the term "container" refers to one or more component parts of the container, i.e., the body, the cap, the nozzle, the handle, or all of the container, i.e., the body and the cap. When used in a container, it is generally desirable that the polymer composition exhibit suitable mechanical properties.

The product may include a container made from the polymer composition and a label associated with the container that provides information about the container to a potential purchaser, i.e., the container includes renewable materials. Such container-related indicia include labels, inserts, pages in magazines or newspapers, stickers, coupons, flyers, displays in or at the end of an aisle, and sales items intended to be taken by a potential purchaser or left in the area proximate to the product.

Products made from the polymer compositions described herein can be recovered in existing polyolefin recovery infrastructure.

Test methods

The compositions and containers of the present invention were evaluated using the following procedures. The mechanical properties of the containers were tested using an impact drop test. The mechanical properties of the recycle containers of the invention were evaluated using a recycle simulation method.

Impact drop test：

The container was filled with ambient tap water (to about 0.5 inches from the top of the container) and then sealed. The container was placed on the platform of an l.a.b. impact drop test apparatus (Columbus McKinnon Corporation, Amherst, NY) having an initial drop height of about 1 foot. The release arm of the l.a.b. device is then actuated to drop the container onto the control surface of the l.a.b. device. If the container is able to withstand the drop (no leak), the height of the l.a.b. apparatus is increased in 1 foot increments, up to 7 feet. The same container is dropped until the container fails to withstand the drop or the drop height has reached 7 feet (i.e., the container is able to withstand a drop of 7 feet height). The maximum height (up to 7 feet) that the container can withstand is recorded as the drop height. The test was then repeated at least twice according to the following procedure: the drop height of the l.a.b. equipment was then set to the previous container test minus a drop height of 2 feet (if the drop height of the previous container test did not reach two feet or more, the height of the l.a.b. equipment was set to zero). After three or more containers were tested according to the above procedure, the average drop height was calculated.

The above test can be performed with the container in either the horizontal or vertical direction. In the horizontal direction, one side of the container is placed on the platform of the l.a.b. apparatus, while in the vertical direction the container is erected upright on the platform of the apparatus.

Table 1 summarizes the mechanical properties (according to the impact drop test described previously) and processability of several different bottles. The bottles were extrusion blow-molded (according to the method described in examples 1-1 h) and contained varying amounts of PLA and NRMSEA,Strong 100 (some bottles do not contain PLA or NRMSEA). The quality of the extrudate and bottles was qualitatively assessed as good, medium, poor, very poor, or unacceptable. Good quality extrudates and bottles are characterized by: the wall thickness of the extrudate (parison) and bottle is uniform and the inner and outer surfaces are not rough. The medium quality extrudates and bottles are characterized by: the wall thickness is uniform but the surface is somewhat rough, especially inside the bottle. Poor quality extrudates and bottles are characterized by: there are areas of uneven wall thickness and more widely distributed surface roughness. Poor quality extrudates and bottles are characterized by: blocking of the extruded melt, non-uniform wall thickness throughout the area, and widely distributed surface roughness. Finally, extrudates and bottles of unacceptable quality are characterized by: low melt strength of the extrudate and holes in the bottle. The defects in the extrudate generally propagate in the resulting bottle.

TABLE 1

The processability and properties of the bottles of examples 1a and 1b are comparable to those of the bottle of comparative example 1. The processability and performance of the bottle of example 1c was reduced compared to examples 1, 1a, and 1 b. The processability of the bottle of example 1d was similar to the processability of the bottles of examples 1, 1a, and 1b and improved compared to example 1 c. The mechanical properties of the bottle of example 1d were also improved compared to example 1 c. For example 1e, bursting (parison tear) was common and almost 75% of the bottles produced had holes. The processability and properties of the bottle of example 1e are reduced compared to example 1 c. For example 1f, the processability and mechanical properties of the bottles were significantly improved compared to the bottles of example 1 e; the bottles with holes were less than 10%. For example 1g, the bursting problem was outstanding and all bottles produced had holes (no drop test was performed). The processability of the bottle of example 1g is reduced compared to all other examples. The bottle of example 1h had improved processability compared to the bottle of example 1 g. However, the quality of the extrudates and bottles in example 1g was still unacceptable (no drop test was performed).

Recovery simulation：

To simulate the recovery process, the containers were pelletized using a pelletizer (model TFG1624.50, available from Granutec, eastdoughlas, MA). The granulated material was washed in a 1 wt% aqueous NaOH solution containing 0.1 wt% Triton-X surfactant for 30 minutes at 85 ℃. The washed particles were then rinsed with cold water and then placed in a room of constant temperature and humidity (90 ° F and 60% RH) for seven days. The granules were then dried at 180 ° F for 1 day.

The particles produced by this simulated recovery method were then used to produce a recycle container according to the method described in examples 2 '-2 d'. The recycled container is then subjected to the shock drop test described above.

Table 2 summarizes the mechanical properties (according to the impact drop test described above) and processability of several different recycled bottles (2a '-2 d') compared to similar bottles (2a-2d) prepared from the original material.

The bottles are extrusion blow molded and contain varying amounts of PLA and NRMSEA,Strong 100 (some bottles do not contain PLA or NRMSEA). The quality of the extrudates and bottles was qualitatively assessed as described above.

TABLE 2

Overall, the data in table 2 demonstrate similar or even slight improvements in the processability and performance of the recycled bottles compared to the original bottles.

Examples

Example 1 (comparative)

100% of B54-25H-127HDPE copolymer (INEOS Olefins & Polymers USA, Legue City, TX) was added to the hopper of a Kautex single-chamber extrusion blow molding machine (Kautex MaschinenbauGmbH, Bonn, Germany). The temperature of the extrusion zone was set at 320 ° F, 340 ° F, 360 ° F, and 380 ° F and a general purpose screw having a pineapple kneading section was used. Boston bottles were produced having a volume of about 400mL and a weight of about 30 g.

Example 1a

Pellets of 95% B54-25H-127HDPE copolymer and 5% 4042D PLA from NatureWorks LLC (dried according to the manufacturer's instructions) were added to a mechanical paddle mixer. The mechanical paddle stirrer was run at 60rpm for 1 minute to achieve good macro-uniformity. The dry blend was transferred from the paddle stirrer to the hopper of a Kautex blow molding machine. The extrusion zones were set at 320 ° F, 340 ° F, 360 ° F, and 380 ° F and a general screw with a pineapple kneading zone was used. About 400mL boston bottles were produced with a target weight of about 30 g.

Example 1b

94.4% of B54-25H-127HDPE copolymer, 5.0% of 4042D PLA (dried according to the manufacturer's instructions), and 0.6% of a blend obtained from E.I. DuPont De memories and CompanyThe pellets of Strong 100 were added to a mechanical paddle stirrer and processed as described in example 1a to make 400mL Boston bottles.

Example 1c

Pellets of 90% B54-25H-127HDPE copolymer and 10% 4042D PLA (dried according to the manufacturer's instructions) were added to a mechanical paddle mixer and processed as described in example 1a to make 400mL Boston bottles.

Example 1d

88.8% of B54-25H-127HDPE copolymer, 10.0% of 4042D PLA (dried according to the manufacturer's instructions), and 1.2% ofThe pellets of Strong 100 were added to a mechanical paddle stirrer and then added as described in example 1aA400 mL Boston vial was prepared.

Example 1e

Pellets of 85% B54-25H-127HDPE copolymer and 15% 4042D PLA (dried according to the manufacturer's instructions) were added to a mechanical paddle mixer and processed as described in example 1a to make 400mL Boston bottles.

Example 1f

83.4% of B54-25H-127HDPE copolymer, 15.0% of 4042D PLA (dried according to the manufacturer's instructions), and 1.6% ofThe pellets of Strong 100 were added to a mechanical paddle stirrer and processed as described in example 1a to make 400mL Boston bottles.

Example 1g

Pellets of 80.0% B54-25H-127HDPE copolymer and 20.0% 4042D PLA (dried according to the manufacturer's instructions) were added to a mechanical paddle mixer and processed as described in example 1a to make 400mL Boston bottles.

Example 1h

77.8% of B54-25H-127HDPE copolymer, 20% of 4042D PLA (dried according to the manufacturer's instructions), and 2.2% ofThe pellets of Strong 100 were added to a mechanical paddle stirrer and processed as described in example 1a to make 400mL Boston bottles.

Example 2 (comparative)

Pellets of 100% B54-25H-127HDPE copolymer were added to the feed hopper of a Kautex single cavity extrusion blow molding machine. The extrusion zones were set at 320 ° F, 340 ° F, 360 ° F, and 380 ° F and a general screw with a pineapple kneading zone was used. About 400mL boston bottles were produced with a target weight of about 30 g.

Example 2' (comparative)

To simulate the recycling process, the bottles of example 2 were pelletized as described above. The pellets were added to the feed hopper of a Kautex single chamber extrusion blow molding machine and processed as in example 2 to make 400mL boston bottles.

Example 2a

Pellets of 90% B54-25H-127HDPE copolymer and 10% 4042D PLA (dried according to the manufacturer's instructions) were added to a mechanical paddle mixer and processed as described in example 2 to make 400mL Boston bottles.

Example 2 a'

To simulate the recycling process, the bottles of example 2a were pelletized as described above. The pellets were added to the feed hopper of a Kautex single chamber extrusion blow molding machine and processed as in example 2' to make 400mL boston bottles.

Example 2b

88.8% of B54-25H-127HDPE copolymer, 10.0% of 4042DPellets of PLA (dried according to the manufacturer's instructions), and 1.2% ofThe Strong 100 pellets were added to a mechanical paddle stirrer and then processed as described in example 2 to make 400mL boston bottles.

Example 2 b'

To simulate the recycling process, the bottles of example 2b were pelletized as described above. The pellets were added to the feed hopper of a Kautex single chamber extrusion blow molding machine and processed as in example 2' to make 400mL boston bottles.

Example 2c

Pellets of 85.0% B54-25H-127HDPE copolymer and 15% 4042D PLA (dried according to the manufacturer's instructions) were added to a mechanical paddle stirrer and then processed as described in example 2 to make 400mL Boston bottles.

Example 2 c'

To simulate the recycling process, the bottles of example 2c were pelletized as described above. The pellets were added to the feed hopper of a Kautex single chamber extrusion blow molding machine and processed as in example 2' to make 400mL boston bottles.

Example 2d

82.8% of B54-25H-127HDPE copolymer, 15.0% pounds of 4042D PLA (dried according to the manufacturer's instructions), and 2.2% ofThe pellets of Strong 100 were added to a mechanical paddle stirrer and then processed as described in example 2 to make 400mL Boston bottles.

Example 2 d'

To simulate the recycling process, the bottles of example 2d were pelletized as described above. The pellets were added to the feed hopper of a Kautex single chamber extrusion blow molding machine and processed as in example 2' to make 400mL boston bottles.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Rather, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, the disclosed dimension "40 mm" is intended to mean "about 40 mm".

Each document cited herein, including any cross-referenced or related patent or patent application, is hereby incorporated by reference in its entirety unless expressly stated otherwise or limited otherwise. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to the term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims (17)

1. A polymer composition for molding into an article, the polymer composition comprising ethylene, CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴Wherein R is a linear or branched alkyl group, a polylactic acid polymer and a polyolefin polymer, wherein R is a linear or branched alkyl group¹Is hydrogen or alkyl having 1 to 8 carbon atoms, R²Is an alkyl radical having from 1 to 8 carbon atoms, R³Is hydrogen or alkyl having 1 to 6 carbon atoms, and R⁴The concentration of the polylactic acid polymer is more than 0.1% by weight as glycidyl groupsAnd less than 15 wt%.

2. The polymer composition for molding into articles of claim 1 wherein the concentration of said polylactic acid polymer is greater than 10 weight percent and less than 15 weight percent.

3. The polymer composition for molding into articles of claim 1 wherein the concentration of said polylactic acid polymer is greater than 0.1 weight percent and less than 10 weight percent.

4. The polymer composition for molding into articles of claim 1 wherein the concentration of said polylactic acid polymer is greater than 1 weight percent and less than 8 weight percent.

5. The polymer composition for molding into articles of claim 1 wherein the concentration of said polylactic acid polymer is greater than 2 weight percent and less than 6 weight percent.

6. The polymer composition of claim 1, wherein the polyolefin is a polyalphaolefin homopolymer or copolymer selected from the group consisting of: linear or branched polyalphaolefins.

7. The polymer composition of claim 6, wherein the polyalphaolefin homopolymer or copolymer is a linear polyalphaolefin.

8. The polymer composition of claim 7, wherein the linear polyalphaolefin is a linear polyalphaolefin selected from the group consisting of: high density polyethylene and polypropylene.

9. The polymer composition of claim 8, wherein the linear polyalphaolefin is high density polyethylene.

10. The polymer composition of claim 6, wherein the polyalphaolefin homopolymer or copolymer is a branched polyalphaolefin.

11. The polymer composition of claim 1, wherein the ethylene, CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴Is present in a weight ratio of from 1: 1 to 1: 25 with the polylactic acid polymer.

12. The polymer composition of claim 1, wherein the ethylene, CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴Is present in a weight ratio of from 1: 8 to 1: 12 with the polylactic acid polymer.

13. The polymer composition of claim 1, wherein the ethylene, CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴Is present in a 1: 10 weight ratio to the polylactic acid polymer.

14. An article made from the polymer composition of claim 1, wherein the article is a container.

15. A method of forming a polymeric article, the method comprising:

mixing ethylene and CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴With a polylactic acid polymer and a polyolefin polymer, wherein R is¹Is hydrogen or alkyl having 1 to 8 carbon atoms, R²Is an alkyl radical having from 1 to 8 carbon atoms, R³Is hydrogen orAlkyl having 1 to 6 carbon atoms, and R⁴Is a glycidyl group, the concentration of the polylactic acid polymer being more than 0.1 wt% and less than 15 wt%;

mixing ethylene and CH₂＝C(R¹)CO₂R²And CH₂＝C(R³)CO₂R⁴Extruding a blend of the ethylene copolymer, the polylactic acid polymer, and the polyolefin polymer of (a); and molding the extruded blend into an article, wherein the molding comprises extrusion blow molding.

16. The method of forming a polymeric article of claim 15, wherein the concentration of the polylactic acid polymer is greater than 0.1 wt% and less than 10 wt%.

17. The method of forming a polymeric article of claim 15, wherein the concentration of the polylactic acid polymer is greater than 10 weight percent and less than 15 weight percent.